JP2018180164A - Screen and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen and a display device having an optical sheet containing a plurality of particles, which can maintain a speckle reduction effect for a long period of time and can exhibit excellent diffuse reflection characteristics. A screen that is irradiated with image light from a projector and displays an image has an insulating liquid, a holding layer that is swollen by the insulating liquid, and a plurality of particles that are rotatably held by the holding layer. An optical sheet having a particle layer, an electrode that forms an electric field for rotating particles by applying a voltage, and an image light radiated from a projector to face the display surface of the optical sheet on which an image is displayed. It is provided with a reflective layer provided on the opposite surface side, and the particles include a first polymer portion and a second polymer portion. [Selection diagram] Fig. 1

Description

  The present disclosure relates to a screen and a display device using an optical sheet.

  Conventionally, a projector using a coherent light source is used. As coherent light, for example, laser light oscillated from a laser light source is used. When the image light emitted from the projector is formed by the coherent light, speckle is observed on the screen on which the image light is projected. Speckles, which are recognized as innumerable light and dark spots, degrade the displayed image on the screen and cause the viewer to feel uncomfortable. Heretofore, there has been proposed a technique of temporally changing the incident angle of the image light incident on each position on the screen for the purpose of reducing the speckle (see Patent Document 1). By this technique, an uncorrelated scattering pattern can be superimposed on the screen to reduce speckle.

  Further, as a technique for reducing the above-mentioned speckles, a charged light diffusing particle for diffusing projected light, a light diffusing layer having a dispersion medium for dispersing the light diffusing particle, and the light diffusing layer A video projection screen has been proposed that includes a pair of electrodes disposed so as to be sandwiched from the optical axis direction, applies a voltage between the electrodes, generates an electric field in the light diffusion layer, and moves the light diffusion particles Patent Document 2).

International Publication 2012/033174 Pamphlet JP, 2013-223176, A

  In the technology described in Patent Document 2, a light diffusion layer constituted by a plurality of containers containing a plurality of light diffusion particles together with a dispersion medium is sandwiched between a pair of electrodes, and the light diffusion layer is By applying a voltage between a pair of sandwiching electrodes, an electric field can be formed in the light diffusion layer, whereby the light diffusion particles contained in the light diffusion layer can be moved and speckle can be reduced. However, in a reflective screen that diffuses and reflects the image light emitted from the projector by the light diffusing particles and allows the observer to observe the image, light is emitted so as to exhibit desired diffuse reflection characteristics while reducing speckles. There is a problem that it is difficult to control the motion of the diffusing particles.

  In addition, since a plurality of light diffusion particles exist inside the container, the charged light diffusion particles adhere to each other inside the container by repeatedly applying an electric field to the light diffusion layer, whereby the light diffusion particles Exercise will be reduced. Therefore, there is a problem that the speckle reduction effect due to the movement of the light diffusion particles is deteriorated according to the use frequency of the screen.

  In view of the above problems, the present invention provides a screen and a display device having an optical sheet that includes a plurality of particles, and the speckle reduction effect can be sustained over a long period of time and can exhibit excellent diffuse reflection characteristics. One purpose is to provide.

  In order to solve the above-mentioned problems, according to an embodiment of the present invention, a screen on which an image light is irradiated from a projector and an image is displayed, and which is an insulating liquid and a holding layer swollen by the insulating liquid An optical sheet having a particle layer having a plurality of particles rotatably held by the holding layer, an electrode forming an electric field for rotating the particles by applying a voltage, and an image from the projector A reflective layer provided on the side opposite to the display surface of the optical sheet on which light is emitted and the image is displayed, and the particles include a first polymer portion and a second polymer portion A screen is provided.

  The first polymer portion and the second polymer portion may have different relative dielectric constants, and the reflective surface of the reflective layer located on the optical sheet side may have an uneven structure, and the unevenness thereof The structure may be periodic, for example, having a sawtooth shape.

  The reflection layer may be a wavelength selective reflection layer that reflects image light emitted from the projector but transmits light in a wavelength band different from that of the image light, and the image light emitted from the projector is And at least a first image light of a first wavelength band, a second image light of a second wavelength band, and a third image light of a third wavelength band, wherein the first wavelength band, the second wavelength band, and the third wavelength The bands are different wavelength bands, and the reflection layer selectively reflects the first image light but transmits the second image light and the third image light, and the second reflection layer A second reflective layer which selectively reflects image light but transmits the first image light and the third image light, and selectively reflects the third image light, the first image light and the second At least a third reflective layer for transmitting image light Or a laminate composed.

  The holding layer may include a plurality of holding portions rotatably holding each of the plurality of particles, and the particles may be a single color, and the first polymer portion of the particles and the second The polymer portion may be transparent.

  According to an embodiment of the present invention, there is provided a display device comprising a projector for emitting coherent light and the screen. In this display device, the reflective surface located on the opposite surface side of the optical sheet in the reflective layer can diffusely reflect the image light emitted from the projector in a direction substantially parallel to the normal direction of the screen The apparatus may have a structure, and may further include a power source for applying a voltage to the electrodes of the screen, and a control device for controlling a voltage applied from the power source to the electrodes, The control device can control the voltage applied from the power source to the electrode so that the particles repeatedly rotate within a range where the rotation angle of the particles is less than 180 °, the normal direction of the screen From the power source to the electrode such that at least a portion of the second polymer portion is covered by the first polymer portion when viewed from the viewer side along the The voltage to be pressurized, may control the orientation and / or position of the particle.

  According to the present invention, it is possible to provide a screen and a display device having an optical sheet which includes a plurality of particles, and the speckle reduction effect can be sustained over a long period of time and can exhibit excellent diffuse reflection characteristics. it can.

FIG. 1 is a schematic configuration view showing a display device according to an embodiment of the present invention. FIG. 2 is a plan view showing a method of irradiating image light from a projector of a display device on a screen according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a schematic configuration of a screen in an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a schematic configuration of another aspect of the screen in one embodiment of the present invention. FIG. 5 is a cross-sectional view showing a schematic configuration of another aspect of the screen in one embodiment of the present invention. FIG. 6 is a cross-sectional view showing a schematic configuration of another aspect of the screen in one embodiment of the present invention. FIG. 7 is a cross-sectional view showing a schematic configuration of another aspect of the screen in one embodiment of the present invention. FIG. 8 is a cross-sectional view (part 1) showing a schematic configuration of particles contained in an optical sheet according to an embodiment of the present invention. FIG. 9 is a cross-sectional view (part 2) showing a schematic configuration of particles contained in an optical sheet according to an embodiment of the present invention. FIG. 10 is a cross-sectional view (part 3) showing a schematic configuration of particles contained in an optical sheet according to an embodiment of the present invention. FIG. 11 is a graph showing waveforms of voltages applied to the first electrode and the second electrode according to an embodiment of the present invention. FIG. 12 is a cross-sectional view showing another aspect of the screen in an embodiment of the present invention. FIG. 13 is a cross-sectional view showing a schematic configuration of another aspect of the screen in one embodiment of the present invention. FIG. 14 is a cross-sectional view showing another aspect of an optical sheet containing particles in an embodiment of the present invention.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the shapes, scales, dimensional ratios of dimensions, etc. of the respective parts may be changed or exaggerated from the actual ones for easy understanding.

  The numerical range represented using "-" in this specification etc. means that it is the range which includes each of the numerical value described before and behind "-" as a lower limit and an upper limit.

  In the present specification and the like, terms such as "film", "sheet", "plate" and the like are not distinguished from each other based on difference in designation. For example, "plate" is a concept that also includes members that can be generally called "sheet" and "film".

  FIG. 1 is a schematic configuration view showing a display apparatus according to the present embodiment, and FIG. 2 is a plan view showing a method of irradiating image light from a projector of the display apparatus to the screen in the present embodiment. FIG. 7 is a cross-sectional view showing a schematic configuration of another aspect of the screen in the present embodiment, and FIGS. 8 to 10 are cross-sectional views showing a schematic configuration of particles contained in the optical sheet in the present embodiment and the operation thereof. It is.

  As shown in FIG. 1, the display device 1 according to the present embodiment includes a projector 10, a screen 20 on which image light (light for forming an image) is projected from the projector 10, and a voltage to the screen 20. The power source 30 to apply and the control apparatus 40 which controls the voltage applied to the screen 20 from the power source 30 are provided.

  The projector 10 which projects the image light onto the screen 20 has a coherent light source 11 which oscillates coherent light, and a scanning device (not shown) which adjusts the light path of the coherent light source 11. Examples of the coherent light source 11 include a laser light source that oscillates a laser beam. In the coherent light source 11, different wavelength bands (for example, a first wavelength band corresponding to blue (B), a second wavelength band corresponding to green (G), a third wavelength band corresponding to red (R), etc.) It may consist of a plurality of coherent light sources which generate the light of 2.).

  The projector 10 in the present embodiment projects coherent light on the screen 20 by a raster scan method. The projector 10 projects coherent light so as to scan the entire area on the screen 20 at high speed (see FIG. 2). The projector 10 projects coherent light only to the position on the screen 20 where the image is to be formed, depending on the image to be formed. Thus, an image is formed on the screen 20. The above operation of the projector 10 may be controlled by the control device 40 or may be controlled by a control device separate from the control device 40.

  The screen 20 includes an optical sheet 50 having a first surface 50 a and a second surface 50 b opposite to the first surface 50 a, a first electrode 21 extending in a planar manner on the first surface 50 a of the optical sheet 50, and a second surface of the optical sheet 50. 50b, a second electrode 22 extending in a plane, a first cover layer 23 covering the first electrode 21 to form one outermost surface of the screen 20, and a second cover layer 24 covering the second electrode 22 And a reflective layer 25 provided on the second cover layer 24 with the adhesive layer 26 interposed therebetween. The first electrode 21 and the second electrode 22 are electrically connected to the power source 30. The screen 20 includes a light diffusion layer (a layer formed by dispersing fine particles in an acrylic resin or the like), a tint layer (a layer that absorbs incident external light from the first cover layer 23 side), and the like. It is also good. Moreover, you may provide functional layers, such as a reflection prevention layer, as needed.

  The screen 20 in the present embodiment is a reflective screen, and the projector 10 projects image light on a display surface 20 a configured by the outer surface of the first cover layer 23. The image light projected onto the display surface 20 a is transmitted through the first cover layer 23 and the first electrode 21 and diffused and transmitted by the optical sheet 50. The diffusely transmitted image light passes through the second electrode 22 and the second cover layer 24 and is reflected by the reflective layer 25. The image light reflected by the reflective layer 25 is transmitted through the second cover layer 24 and the second electrode 22, diffused and transmitted by the optical sheet 50, and transmitted through the first electrode 21 and the first cover layer 23. Thus, the observer can observe the image by facing the display surface 20 a of the screen 20.

  The light transmittance (visible light transmittance) of the visible light region of the first electrode 21, the second electrode 22, the first cover layer 23, and the second cover layer 24 through which image light is transmitted is 80% or more. Preferably, it is 84% or more. In addition, the visible light transmittance | permeability in this embodiment is an average value of the transmittance | permeability in each wavelength when it measures within the measurement wavelength of 380 nm-780 nm using a spectrophotometer (Shimadzu Corporation make, UV-3100PC) etc. Defined as

  As a conductive material which comprises the 1st electrode 21 and the 2nd electrode 22, ITO (Indium Tin Oxide), InZnO (Indium Zinc Oxide), Ag nanowire, a carbon nanotube etc. are mentioned, for example. The first cover layer 23 and the second cover layer 24 are layers for protecting the first electrode 21, the second electrode 22 and the optical sheet 50, and, for example, polyethylene terephthalate, polycarbonate, cycloolefin having excellent stability It may be composed of a transparent resin such as a polymer.

  The reflective layer 25 is a reflective film capable of reflecting the image light transmitted through the first cover layer 23, the first electrode 21, the optical sheet 50, the second electrode 22 and the second cover layer 24, a reflective plate, a dielectric multilayer film, It comprises a holographic mirror etc.

  The reflective surface 25A located on the second cover layer 24 side in the reflective layer 25 may be a substantially flat surface as shown in FIG. 3, or a prism sheet having a sawtooth shape as shown in FIG. 4, a Fresnel lens, It may be a linear Fresnel lens or the like. In the case of a Fresnel lens, the center of the lens may or may not coincide with the center of the screen. In the case of a linear Fresnel lens, the centerline of the lens may or may not pass through the center of the screen. In addition, the reflecting surface 25A may have a periodic uneven shape other than the sawtooth shape, such as a microlens array, a lenticular lens, or a corner cube array. The reflective surface 25A may have a random uneven shape as shown in FIG. 5, or may be a retroreflective surface. Since the reflecting surface 25A has a sawtooth shape (see FIG. 4), the image is viewed from the direction inclined with respect to the normal direction of the screen 20 from the projector 10 installed at a short distance (about 10 cm to 50 cm) to the screen 20 By making light incident, it is possible to reflect the image light in the normal direction of the screen 20 and to prevent light other than the image light (for example, external light etc.) from being reflected to the front, so display The contrast of the image displayed on the surface 20a can be improved. In addition, since the reflecting surface 25A has a random uneven shape (see FIG. 5), the control of the diffuse reflection characteristics by the screen 20 is facilitated. Specifically, by controlling the roughness of the uneven shape of the reflecting surface 25A, it becomes possible to control the diffusion profile (reflection angle characteristic of the reflected light intensity). Note that the reflective layer 25 having the reflective surface 25A with random asperity shape shown in FIG. 5 may be manufactured by forming the asperity shape by sandblasting or shot blasting the flat surface, It may be manufactured by forming the uneven | corrugated shape by the forming process.

  As shown in FIG. 6, the reflective layer 25 is a wavelength selective reflective layer that reflects image light emitted from the projector 10 and transmits light of a wavelength different from that of the image light (for example, external light). It is also good. According to such a reflection layer 25, only image light can be selectively reflected, and the contrast of the image displayed on the display surface 20a can be improved. In the reflection layer 25 shown in FIG. 6, the image light emitted from the projector 10 is the first image light of the first wavelength band corresponding to blue (B) and the second wavelength band corresponding to green (G) Second image light and third image light of a third wavelength band corresponding to red (R), at least one of them image light of at least one wavelength band (for example, first image light of a first wavelength band and It may be a wavelength selective reflection layer that reflects the second image light of the second wavelength band and transmits image light of another wavelength band (for example, the third image light of the third wavelength band).

  Further, as shown in FIG. 7, the image light emitted from the projector 10 is the first image light of the first wavelength band corresponding to blue (B), and the second of the second wavelength band corresponding to green (G). A first reflective layer 251 that includes at least image light and third image light of a third wavelength band corresponding to red (R), and reflects the first image light among them, and second that reflects the second image light It may be a laminate of the reflective layer 252 and a third reflective layer 253 that reflects the third image light.

  As shown in FIGS. 3 to 7, the optical sheet 50 is provided with a particle layer 53 provided between the first base 51, the second base 52, and the first base 51 and the second base 52. And The first base 51 supports the first electrode 21, and the second base 52 supports the second electrode 22. The particle layer 53 is sealed between the first base 51 and the second base 52. The first base 51 and the second base 52 can be made of a material capable of sealing the particle layer 53 and having sufficient strength to support the first electrode 21 and the second electrode 22. The first base 51 and the second base 52 may be made of, for example, a polyethylene terephthalate resin film or the like. The first base 51 and the second base 52 are transparent to the extent that they can transmit image light, and are preferably similar to the first electrode 21, the second electrode 22, the first cover layer 23, and the second cover layer 24. The visible light transmittance of In the screen 20 according to the present embodiment, as shown in FIG. 13, the first base 51 of the optical sheet 50 has an electrode material layer 21 ′ on one side, and the second base 52 on one side. 22 and the electrode material layers 21 ′ and 22 ′ are directed to the particle layer 53 side, and the particles are formed by the first base material 51, the second base material 52, and the frame-like spacer member 58. The layer 53 may be sealed. In the screen 20 having such a configuration, the electrode material layers 21 ′ and 22 ′ function as the first electrode 21 and the second electrode 22, and the first base 51 and the second base 52 function as the first cover layer 23 In order to have the function as the second cover layer 24, the first electrode 21, the second electrode 22, the first cover layer 23 and the second cover layer 24 can be omitted.

  The particle layer 53 has a holding layer 54 and a plurality of particles 55 rotatably held by the holding layer 54. In the present embodiment, the holding layer 54 has a plurality of cavities 56 capable of containing each particle 55, and the inner dimension of each cavity 56 is larger than the outer dimension of the particles 55 contained in the cavity 56. . Thereby, the particles 55 are rotatably held in the cavity 56 of the holding layer 54.

  The holding layer 54 is swelled by the insulating liquid 57, and in the cavity 56, the insulating liquid 57 is filled between the holding layer 54 and the particles 55. Since the holding layer 54 is swollen by the insulating liquid 57, the particles 55 in each cavity 56 can be rotated stably and smoothly.

The insulating liquid 57 in this embodiment has a 5.5 mm ² / s or less kinematic viscosity (25 ° C.), preferably 0.65mm ² /s~5.5mm ² / s kinematic viscosity (25 ° C.) Have. When the kinematic viscosity (25 ° C.) of the insulating liquid 57 is 5.5 mm ² / s or less, an excellent speckle reduction effect can be exhibited over a long period of time.

  Examples of the insulating liquid 57 include silicone oils such as dimethyl silicone oil and modified silicone oil, isoparaffin solvents, straight chain paraffin solvents, straight chain alkane solvents such as dodecane and tridecane, mineral oil based processing oils, and the like And combinations of two or more of the above. In particular, it is preferable to use, as the insulating liquid 57, one prepared by mixing one silicone oil or two or more silicone oils.

  The holding layer 54 may be made of, for example, an elastomeric sheet made of an elastomeric material. The holding layer 54 constituted by the elastomer sheet can be swollen by the insulating liquid 57. Examples of the material of the elastomer sheet include silicone resin, (finely crosslinked) acrylic resin, (finely crosslinked) styrene resin, and polyolefin resin.

  The cavities 56 of the holding layer 54 are distributed with high density in the in-plane direction of the screen 20 and also distributed in the normal direction of the screen 20. In the embodiment shown in FIGS. 1 and 3 to 7, the cavities 56 are arranged substantially uniformly in three lines along the in-plane direction of the screen 20, but the invention is not limited to this embodiment.

  The particles 55 held in the cavity 56 of the holding layer 54 have a function of changing the traveling direction of the image light projected from the projector 10 and transmitting it, that is, a function of diffusing and transmitting the image light. The particle 55 includes a first portion 551 and a second portion 552 having different relative dielectric constants. Therefore, a dipole moment is generated in the particle 55 in the electric field. At this time, the particle 55 operates to make the vector of its dipole moment and the vector of the electric field antiparallel. Therefore, when a voltage is applied between the first electrode 21 and the second electrode 22 and an electric field is formed in the optical sheet 50 located between the first electrode 21 and the second electrode 22, the particles 55 ) In the cavity 56 so as to take a stable posture with respect to The screen 20 in the present embodiment can change the diffusion wavefront as the particle 55 having the light diffusion function rotates. In the present embodiment, as described later, as the particles 55 rotate by the electric field formed in the optical sheet 50, the speckle reduction effect is exhibited. Therefore, the relative permittivity of the first portion 551 and the second portion 552 is different if the particles 55 can be rotated by the electric field formed in the optical sheet 50 and the speckle reduction effect can be exhibited. Good. Whether or not the relative dielectric constants of the first portion 551 and the second portion 552 are different from each other can be determined based on whether or not the particles 55 can be rotated by the electric field formed in the optical sheet 50.

  A particle 55 including a first portion 551 and a second portion 552 different in relative dielectric constant, for example, is a resin in which spherical particles of organic or inorganic substance are arranged in a single layer by adhesive tape etc. Method of depositing a layer or inorganic layer on a hemispherical surface (vapor deposition method): Method of using a rotating disk; contacting two kinds of droplets different in relative dielectric constant from each other in air using a spray method, an ink jet method, etc. And a method of forming one droplet;

  According to the microchannel manufacturing method, the first portion 551 and the second portion 552 having different relative dielectric constants can be formed using materials having different charging characteristics. Specifically, using the continuous phase and the particulate phase in an oil / water (O / W type) or aqueous / oil (W / O type) relationship with each other, the first micro phase to which the continuous phase is transferred is used. By sequentially discharging a continuous phase containing two kinds of materials having different charging characteristics from the channel into the particleization phase of the flowing medium flowing to the second microchannel, it is a bilayer polymer particle, and charge- Dipolar particles having a polarity of ±) can be produced (see Japanese Patent Application Laid-Open No. 2004-197083).

  In a microchannel manufacturing method, in an oil-based or aqueous fluid medium containing a polymerizable resin component, the polymerizable resin components in the continuous phase which is insoluble in the medium are charged differently and positively or negatively. The continuous phase is continuously or intermittently discharged into the aqueous or oily particle-forming phase flowing in the second microchannel. Next, since the discharge material discharged into the particle formation phase is formed into particles during a series of discharge, dispersion, and transfer in the microchannel, the polymerizable resin component in the particles is subjected to UV irradiation and / or The particles 55 are produced by polymerization curing under heating.

  The polymerizable resin component or the polymerizable monomer used for the particles 55 may be, for example, (-) chargeability depending on the kind of functional group or substituent which the polymerizable resin component or the polymerizable monomer has in its chemical structure. Monomer species that tend to exhibit (+) chargeability can be used. Therefore, in the case where at least two or more kinds of polymerizable monomers are used as the polymerizable resin component, in consideration of their tendency to exhibit (+) and (-) chargeability, it is preferable to use the same tendency of chargeability. A plurality of certain polymerizable monomers can be used in combination as appropriate. In addition, additives other than monomers, such as a polymerization initiator, may be adjusted and added to such an extent that the chargeability of the entire material is not lost.

  As a functional group and / or a substituent which a polymeric resin component or a polymerizable monomer has in its chemical structure, for example, a carbonyl group, a vinyl group, a phenyl group, an amino group, an amido group, an imide group, a hydroxyl group, a halogen group , Sulfonic acid group, epoxy group, urethane group (urethane bond) and the like.

  Examples of the polymerizable monomer having a tendency of (-) chargeability include phenyl (meth) acrylate, benzyl (meth) acrylate and the like; (meth) acrylate 2-chloroethyl and the like; (meth) acrylonitrile and the like; Meta) glycidyl acrylate, mono or diglycidyl ester of maleic acid, mono or diglycidyl ester of fumaric acid, mono or diglycidyl ester of crotonic acid, mono or diglycidyl ester of tetrahydrophthalic acid, mono or diglycidyl of itaconic acid Esters, mono- or diglycidyl esters of butene tricarboxylic acid, mono- or di-glycidyl esters of citraconic acid, dicarboxylic mono- and alkyl glycidyl esters of mono- or di-glycidyl esters of allyl succinic acid, etc .; alkyl glycidyl esters of p-styrene carboxylic acid (Meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid and polypropylene glycol or polyethylene glycol monoester, lactones and (meth) acrylic acid Adducts with 2-hydroxyethyl and the like; (meth) acrylic acid trifluorodimethyl, (meth) acrylic acid 2-trifluoromethylethyl, (meth) acrylic acid 2-perfluoromethyl ethyl, (meth) acrylic acid -2-perfluoroethyl-2-perfluorobutylethyl, (meth) acrylic acid-2-perfluoroethyl, (meth) acrylic acid perfluoromethyl, (meth) acrylic acid diperfluoromethylmethyl etc .; acrylic acid, Methacrylic acid, tetrahydrophthalic acid, itaconic acid, citraconic , Crotonic acid, maleic acid, fumaric acid, isocrotonic acid, norbornene dicarboxylic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid; maleic anhydride as it derivatives, itaconic anhydride Citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid anhydride, acid halide etc .; γ-methacryloxypropyltrimethoxysilane etc .; ethylene glycol Diacrylic acid ester, diacrylic acid ester of diethylene glycol, diacrylic acid ester of triethylene glycol, diacrylic acid ester of polyethylene glycol, diacrylic acid ester of dipropylene glycol, diacrylic acid ester of tripropylene glycol, etc .; Acrylic acid ester, dimethacrylic acid ester of diethylene glycol, dimethacrylic acid ester of triethylene glycol, diacrylic acid ester of polyethylene glycol, dimethacrylic acid ester of propylene glycol, dimethacrylic acid ester of dipropylene glycol, dimethacrylic acid of tripropylene glycol Acid esters: styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, Chloromethylstyrene, nitrostyrene, acetylstyrene, methoxystyrene, α-methylstyrene , Vinyl toluene, sodium p-styrenesulfonate; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl acrylate and the like Esters of (meth) acrylic acid with bicyclic alcohols, etc .; perfluoroethylene, perfluoropropylene, vinylidene fluoride; vinyltrimethoxysilane, vinyltriethoxysilane; vinyl acetate, vinyl propionate, vinyl n-butyrate, Vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl acetate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl p-t-butyl benzoate, vinyl salicylate, etc .; vinylidene chloride, chlorohexane vinyl carboxylate , Β- Taku Lori acryloyloxyethyl hydrogen phthalate, and the like.

  Examples of the polymerizable monomer which tends to be (+) chargeable include methacrylamide, N-methylol methacrylamide, N-methoxyethyl methacrylamide, N-butoxymethyl methacrylamide, etc .; aminoethyl (meth) acrylate, (meth ) Alkyl ester derivatives of acrylic acid or methacrylic acid such as propylaminoethyl acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, etc. N-vinyldiethylamine And vinylamine derivatives such as N-acetylvinylamine; allylamine, methacrylamine, N-methylacrylamine, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide and the like Derivatives of rylamine series; acrylamide series derivatives such as acrylamide and N-methyl acrylamide; aminostyrenes such as p-aminostyrene; (meth) acrylamides such as N-methylol (meth) acrylamide and diacetone acrylamide; 6-amino Hexylsuccinimide, 2-aminoethylsuccinimide, aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, Acrylic acid or methacrylic acid alkyl ester derivatives such as cyclohexylaminoethyl methacrylate; vinylamine derivatives such as N-vinyldiethylamine, N-acetylvinylamine; allylamine, methacrylic acid Allylamine derivatives such as amines, N-methyl acrylamine, N, N-dimethyl acrylamide, N, N-dimethylaminopropyl acrylamide; acrylamide derivatives such as acrylamide, N-methyl acrylamide; aminostyrenes such as N-aminostyrene And monomers having an amino group-containing ethylenic unsaturated bond such as 6-aminohexyl succinimide and 2-aminoethyl succinimide.

  When particles 55 are manufactured by the microchannel manufacturing method, the speed and merging direction at the time of merging of two types of polymerizable resin components constituting the continuous phase, and the speed and discharging direction at the time of discharge to the particleization phase of the continuous phase are adjusted By doing this, it is possible to adjust the outer shape of the resulting particle 55, the shape of the interface between the first portion 551 and the second portion 552, and the like. In the particle 55 shown in FIGS. 8 to 10, the volume ratio of the first portion 551 and the second portion 552 is the same, and the interface between the first portion 551 and the second portion 552 is formed to be planar. The first portion 551 and the second portion 552 each have a hemispherical shape, and the particle 55 as a whole has a spherical shape.

  In addition, when the two polymerizable resin components forming the continuous phase contain a diffusion component, the first portion 551 and the second portion 552 of the particle 55 can be provided with an internal diffusion function. In the particle 55 shown in FIGS. 8 to 10, the first portion 551 has a first main portion 553 and a first diffusion component 555 dispersed in the first main portion 553. Similarly, the second portion 552 has a second main portion 554 and a second diffusion component 556 dispersed in the second main portion 554. That is, the particles 55 can exhibit a diffusion function to the light traveling in the first portion 551 and the light traveling in the second portion 552. Here, the first diffusion component 555 and the second diffusion component 556 mean components capable of changing the direction of the light in the particle 55 by refraction or the like. For example, the first diffusion component 555 and the second diffusion component 556 are made of a material having a refractive index different from the refractive index of the material forming the first main portion 553 and the second main portion 554 of the particle 55, A light diffusion function (light scattering function) may be performed by the first diffusion component 555 and the second diffusion component 556. As the first diffusion component 555 and the second diffusion component 556 having a refractive index different from the refractive index of the material constituting the first main portion 553 and the second main portion 554, for example, resin beads, glass beads, metal compounds And porous materials containing gas, bubbles and the like.

  In the present embodiment, the particles 55 are colorless and transparent or colored transparent, and if colored and transparent, they are constituted by a single color. That is, the surfaces of the first portion 551 and the second portion 552 are formed of the same color. The color of the surface of the first portion 551 and the second portion 552 can be adjusted by adding a coloring material such as a pigment or a dye to the first portion 551 and the second portion 552. The size and amount of the first and second diffusion components 555 and 556 contained in the particle 55 are adjusted so that the transmittance of light incident on the particle 55 is higher than the reflectance of light incident on the particle 55. Is preferred.

In the present embodiment, “single color” refers to the display surface 20 a of the screen 20 when the particle 55 rotates in the optical sheet 50 (the cavity 56 of the holding layer 54) in a state where an image is not displayed on the screen 20. It means that the color of the display surface 20a of the screen 20 can not be recognized even by the normal observation power by the observer who observes the light having a uniform color. That is, when the first portion 551 faces the display surface 20 a of the screen 20, the image is displayed on the screen 20 when the second portion 552 faces the display surface 20 a of the screen 20. If it is recognized that the color of the display surface 20a of the screen 20 is the same by the normal observation power of the observer, the particle 55 can be said to be a single color. More specifically, when the first portion 551 faces the display surface 20 a of the screen 20, the display surface 20 a of the screen 20 and the second portion 552 face the display surface 20 a of the screen 20. It is preferable that the color difference ΔE ^* ab (= [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2 ) with the display surface 20 a of the screen 20 is 1.5 or less. The color difference ΔE * ab is the lightness L ^* and the chromaticity a in the L ^* a ^* b ^* color system, which is measured using a colorimeter (CM-700d, manufactured by Konica Minolta) in accordance with JIS-Z8730. It is a value specified based on ^* , b ^* . When the screen 20 is of a reflective type, it is preferable that the color difference ΔE ^* ab specified based on the lightness L ^* and the chromaticity a ^* and b ^* of the reflected light is 1.5 or less, and it is a transmissive type. In this case, it is preferable that the color difference ΔE ^* ab specified based on the lightness L ^* and the chromaticity a ^* and b ^* of the transmitted light is 1.5 or less.

The particle layer 53 can be manufactured as follows.
First, an ink in which the particles 55 are dispersed in a polymerizable silicone rubber or the like (material constituting the holding layer 54) is prepared. Next, the ink is stretched using a coater or the like, and further polymerized by heating or the like to obtain an elastomer sheet. The elastomer sheet is swollen in the insulating liquid 57 by immersing the elastomer sheet in the insulating liquid 57 for a certain period. By swelling the elastomer sheet in the insulating liquid 57, a cavity 56 filled with the insulating liquid 57 is formed around the particles 55 contained in the elastomer sheet, and ultrasonic waves are applied as desired. , And the particle layer 53 is manufactured.

  The optical sheet 50 can be manufactured by covering the said particle layer 53 with the 1st base material 51 and the 2nd base material 52, and sealing the particle layer 53 using a lamination or an adhesive agent etc. By laminating the first electrode 21 and the second electrode 22, the first cover layer 23 and the second cover layer 24, and the reflective layer 25 in this order on the both sides of the optical sheet 50 manufactured in this manner, a screen can be obtained. 20 can be manufactured.

  In the display device 1 according to the present embodiment, the optical path by the scanning device (not shown) so that the coherent light from the coherent light source 11 of the projector 10 corresponds to the image to be displayed on the display surface 20a of the screen 20. And projected onto the display surface 20 a of the screen 20. The light projected onto the display surface 20 a of the screen 20 passes through the first cover layer 23 and the first electrode 21 and reaches the optical sheet 50. The light reaching the optical sheet 50 is diffused and transmitted by the particles 55, transmitted through the second electrode 22 and the second cover layer 24, and reflected by the reflective layer 25. The light reflected by the reflective layer 25 passes through the second cover layer 24 and the second electrode 22 and reaches the optical sheet 50 again. The reflected light reaching the optical sheet 50 is diffused and transmitted by the particles 55, transmitted through the first electrode 21 and the first cover layer 23, and emitted in various directions on the display surface 20a side of the screen 20. Thereby, an image corresponding to the area irradiated with the coherent light on the display surface 20a of the screen 20 is observed. When the coherent light source 11 includes a plurality of light sources that emit coherent light in different wavelength bands, a color image may be displayed on the display surface 20 a of the screen 20.

  By the way, when an image is displayed on the display surface 20a of the screen 20 by coherent light, speckle may be observed. Speckle is considered to be caused by causing an interference pattern on the light sensor surface (retina for human beings) after coherent light such as laser light is diffused on the display surface 20 a of the screen 20. In particular, when coherent light is irradiated to the screen 20 by raster scan, coherent light is incident on each position on the screen 20 from a certain incident direction. Therefore, when raster scanning is adopted, speckle wavefronts generated at each point on the screen become immobile as long as the screen 20 does not move, and the speckle pattern is visually recognized by the observer together with the image, and the image quality of the displayed image is significantly degraded. It will be.

The screen 20 of the display device 1 according to the present embodiment includes the first electrode 21 and the second electrode 22 electrically connected to the power source 30, and the power source 30 to the first electrode 21 and the second electrode 22. By applying a voltage, an electric field is formed in the optical sheet 50 located between the first electrode 21 and the second electrode 22. In the particle layer 53 of the optical sheet 50, a plurality of particles 55 each having a first portion 551 and a second portion 552 different in relative dielectric constant from each other are rotatably held. The particles 55 are charged or can generate a dipole moment by forming an electric field at least in the particle layer 53, and thus rotate according to the vector of the electric field formed in the particle layer 53. The particles 55 having a function of changing the traveling direction of light, such as a diffusion function, rotate to diffuse the diffusion characteristics of the screen 20, that is, diffuse the image light L1 projected from the projector 10 as shown in FIGS. The direction of the diffused light L2 that has been transmitted changes with time. Similarly, the reflected light reflected by the reflective layer 25 is diffused and transmitted, and the direction of the diffused light changes with time. This can reduce speckle. In particular, in the screen 20 in the present embodiment, the holding layer 54 holding the particles 55 is swollen by the insulating liquid 57 having a predetermined dynamic viscosity (5.5 mm ² / s or less), so that the particles 55 rotate. Even if the operation is repeated, the particles 55 do not stick to the cavity 56. Therefore, in the optical sheet 50 in the present embodiment and the screen 20 using the same, the speckle reduction effect can be maintained over a long period of time. In addition, since the reflected light for displaying an image on the display surface 20 a of the screen 20 is the light reflected by the reflective layer 25, excellent diffuse reflection characteristics can be exhibited.

  The rotation operation of the particle 55 in this embodiment is to change the orientation and position of the particle 55 so that the charge or dipole moment of the particle 55 has a stable positional relationship with the electric field vector. Therefore, when a constant electric field continues to be applied to the particle layer 53, the rotational movement of the particles 55 is stopped after a certain period. On the other hand, in order to reduce speckle, the rotational movement of the particles 55 needs to be continued. Therefore, the power source 30 applies a voltage to the first electrode 21 and the second electrode 22 so that the electric field (vector) formed in the particle layer 53 changes with time under the control of the control device 40. For example, the power source 30 applies a voltage to the first electrode 21 and the second electrode 22 so as to reverse the electric field vector formed on the optical sheet 50 at predetermined time intervals. Specifically, as shown in FIG. 11, the voltage of X (V) and the voltage of -Y (V) are repeatedly applied to the first electrode 21 and the second electrode 22 from the power source 30. By repeatedly inverting the electric field (vector) in this manner, it is possible to cause the particles 55 to repeatedly perform the rotating operation in one direction and the other direction (see arrows in FIGS. 8 to 10).

  The absolute values of the voltages (X (V) and -Y (V)) applied from the power source 30 to the first electrode 21 and the second electrode 22 may be the same or different. Also, three or more different voltages may be applied. Furthermore, the applied voltage may be changed continuously, such as adopting a normal alternating voltage.

  As described above, according to the screen 20 in the present embodiment, the holding layer 54 of the particle layer 53 is swollen by the insulating liquid 57 having a predetermined dynamic viscosity, and the particles 55 are rotatably accommodated in the cavity 56 As a result, the excellent speckle reduction effect can be maintained for a long time.

  The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

  In the above embodiment, the example of producing the charged particles 55 using the monomer having the chargeability of (+) and the monomer having the chargeability of (−) has been described, but the present invention is limited to this embodiment. It is not a thing. For example, the particles 55 may be produced by laminating two layers of plate-like members made of materials different in chargeability from one another and grinding the laminate to a desired size. As a material having chargeability, for example, a charge control agent (an ion conductivity imparting agent obtained by combining lithium perchlorate or the like with a polymer mainly composed of a polyalkylene glycol used as an antistatic agent) is added. Synthetic resin materials and the like.

  In the above embodiment, the spherical particles 55 are described as an example, but the present invention is not limited to this aspect. As a shape of particle | grains 55, a spheroid, a cube, a rectangular solid, a cone, a cylinder etc. are mentioned, for example. By using the particle 55 having an outer shape other than a spherical body, by operating the particle 55, the temporal change of the diffusion characteristic of the screen 20 by the surface reflection of the particle 55 regardless of the internal diffusion ability of the particle 55 Can cause.

  In the above embodiment, as a laminated structure of the screen 20, a structure in which the first cover layer 23, the first electrode 21, the optical sheet 50, the second electrode 22, and the second cover layer 24 are laminated in this order is exemplified. Although explained, it is not limited to this aspect. For example, a functional layer having an anti-reflection (AR) function, a hard coat (HC) function, an ultraviolet light shielding (reflection) function, an antifouling function, etc. may be separately provided, and the first cover layer 23, the second cover At least one of the layer 24, the first base 51, and the second base 52 may have the above function.

  In the above embodiment, the first electrode 21 and the second electrode 22 have been described as an example in which the first electrode 51 and the second electrode 52 are formed in a planar shape on the first substrate 51 and the second substrate 52, respectively. It is not limited to For example, as shown in FIG. 12, each of the first electrode 21 and the second electrode 22 may include a plurality of striped electrodes 21 a and 22 a and may be disposed on the second base material 52. .

  In the above embodiment, as shown in FIGS. 14A and 14B, at least two cavities 56a may form one cavity 56 continuously. In this case, one cavity 56a may contain one particle 55, and the particle 55 may be held immovably in another continuous cavity 56a.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

Example 1
[Preparation of particle 55]
The following monomer composition A for producing the first portion 551 of the particle 55 and the following monomer composition B for producing the second portion 552 were prepared.

<Monomer Composition A>
Isobornyl acrylate 68 parts by mass Trimethylolpropane triacrylate 28 parts by mass Acrylic acid 2 parts by mass Lauryl peroxide 5 parts by mass Polystyrene beads (manufactured by Sumitomo Chemical Industries, Ltd., product name: SBX-4) 10 parts by mass

<Monomer Composition B>
Isobornyl acrylate 69 parts by mass Trimethylolpropane triacrylate 30 parts by mass dimethylaminoethyl methacrylate 1 part by mass lauryl peroxide 5 parts by mass Polystyrene beads (manufactured by Sumitomo Chemical Industries, Ltd., product name: SBX-4) 10 parts by mass

  Particles 55 were produced by a microchannel method using the above-mentioned monomer composition A and monomer composition B, and an aqueous polyvinyl alcohol solution as a fluid medium. Specifically, the third microchannel and the fourth microchannel are joined to form a V-shape, and the monomer composition A is transferred into the third microchannel, and the monomer composition in the fourth microchannel Object B was transferred. Thus, the continuous phase separated into two phases of the monomer composition A phase and the monomer composition B phase, which is prepared by combining the two, is transferred into the first microchannel to form a fluid medium (polyvinyl alcohol The aqueous solution was intermittently discharged into the second microchannel in which the aqueous solution was flowing to form particles. Then, the particles flowing in the second microchannel were irradiated with UV to polymerize the monomer composition A and the monomer composition B, thereby producing particles 55.

[Manufacture of screen 20]
The particles 55 obtained as described above are dispersed in a mixture of a main component of silicone elastomer and a curing agent and an organic solvent to prepare an ink, and the ink is stretched using a bar coater and further heat polymerized to obtain an elastomer. I got a sheet. This elastomeric sheet was swollen by being immersed in polydimethylsiloxane (KF-96-0.65 CS, Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 0.65 mm ² / s) for a fixed period. An ultrasonic wave was applied to the elastomer sheet swollen with polydimethylsiloxane to produce a particle layer 53. ITO is deposited on the PET film as the first base 51 and the second base 52 to form the electrode material layers 21 ′ and 22 ′, and the electrode material layers 21 ′ and 22 ′ are brought into contact with the particle layer 53. Thus, the particle layer 53 is sealed by the first base material 51, the second base material 52, and the frame-like spacer member made of a PET film having an adhesive layer on both sides, and the durable mirror is formed on the second base material 52. The screen 20 was manufactured by sticking a film (type: 1-2926-01).

Test Example 1 Measurement of Speckle Contrast Laser light emitted from a DPSS laser oscillator (oscillation wavelength 532 nm) as the coherent light source 11 is converted to a spherical wave through a spatial filter, and the spherical wave is converted to a convex lens. The screen was converted to a plane wave via the light source and irradiated to the screen of Example 1. A speckle contrast measurement device (SM01VS09, manufactured by Oxide Corporation) is installed at a position on the light source side 0.6 m away from the screen in the direction of 20 degrees with respect to the normal direction of the screen, and at the time of voltage application (amplitude ± 100 V) , And the speckle contrast (Cs (on), Cs (off)) when no voltage is applied, according to IEC 62906-5-2, respectively, and the speckle reduction rate (= 1- [Cs (on) / Cs (off)] was calculated. As a result, the speckle contrast (Cs (on)) when voltage is applied is 0.09, the speckle contrast (Cs (off)) when voltage is not applied is 0.53, and the speckle reduction rate is 0. It was .83.

From this result, it was confirmed that the speckle can be reduced because the kinematic viscosity of the insulating liquid 57 (silicone oil) which swells the holding layer 54 is 5.5 mm ² / s or less. Also, it was confirmed by visual observation that speckle was reduced. The higher the speckle reduction rate, the better the visual speckle reduction effect.

Test Example 2 Reliability Test A voltage was continuously applied to the screen of Example 1 for 1000 hours (the applied voltage conditions were the same as those of Test Example 1), and then the screen was visually observed. As a result, it was confirmed that the speckle reduction effect was about the same as that immediately after the voltage application. From this, in the screen of Example 1, it is considered that the speckle reduction effect can be sustained without the particles 55 being fixed over a long period of time.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus 10 ... Projector 11 ... Coherent light source 20 ... Screen 21 ... 1st electrode 22 ... 2nd electrode 23 ... 1st cover layer 24 ... 2nd cover layer 50 ... Optical sheet 51 ... 1st base material 52 ... 2nd Base 53 Particle layer 54 Holding layer 55 Particle 551 First portion 552 Second portion 56 Cavity 57 Insulating liquid 58 Frame-like spacer member

Claims (15)

A screen on which image light is emitted from a projector and an image is displayed,
An optical sheet having an insulating liquid, a holding layer swelled by the insulating liquid, and a particle layer having a plurality of particles rotatably held by the holding layer;
An electrode forming an electric field for rotating the particles by applying a voltage;
The projector further comprises: a reflective layer provided on an opposing surface side facing the display surface of the optical sheet on which image light is emitted from the projector and the image is displayed;
The particle comprises a first polymer portion and a second polymer portion. The screen according to claim 1, wherein the first polymer portion and the second polymer portion have different relative dielectric constants. The screen according to claim 1, wherein a reflective surface located on the optical sheet side in the reflective layer has a concavo-convex structure. The screen according to any one of claims 1 to 3, wherein a reflective surface located on the optical sheet side in the reflective layer has a periodic uneven structure. The screen according to any one of claims 1 to 4, wherein the reflecting surface located on the optical sheet side in the reflecting layer has a sawtooth shape. The screen according to any one of claims 1 to 5, wherein the reflection layer is a wavelength selective reflection layer that reflects image light emitted from the projector but transmits light of a wavelength band different from that of the image light. The image light emitted from the projector includes at least a first image light of a first wavelength band, a second image light of a second wavelength band, and a third image light of a third wavelength band,
The first wavelength band, the second wavelength band, and the third wavelength band are different wavelength bands, respectively.
The reflective layer selectively reflects the first image light but transmits the second image light and the third image light, and selectively reflects the second image light. A second reflection layer for transmitting the first image light and the third image light, and a third reflection layer for selectively reflecting the third image light but transmitting the first image light and the second image light The screen according to any one of claims 1 to 6, which is a laminate formed by laminating at least.   The screen according to any one of claims 1 to 7, wherein the holding layer includes a plurality of holding portions rotatably holding each of the plurality of particles. The screen according to any one of claims 1 to 8, wherein the particles are single color. 10. A screen according to any of the preceding claims, wherein the first and second polymer parts of the particles are transparent. A projector that emits coherent light;
The display apparatus provided with the screen in any one of Claims 1-10. A reflective surface located on the opposite surface side of the optical sheet in the reflective layer has a concavo-convex structure capable of diffusely reflecting image light emitted from the projector in a direction substantially parallel to the normal direction of the screen. 11. The display device according to 11. A power source for applying a voltage to the electrodes of the screen;
The display device according to claim 11, further comprising: a control device that controls a voltage applied to the electrode from the power source.   The display device according to claim 13, wherein the control device controls a voltage applied from the power source to the electrode so as to repeatedly rotate the particles within a range where the rotation angle of the particles is less than 180 °.   The controller controls the electrode from the power source such that at least a portion of the second polymer portion is covered by the first polymer portion when viewed from the viewer side along the normal direction of the screen. The display device according to claim 13, wherein the orientation and / or position of the particles is controlled by a voltage applied to the

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