JP2014062980A - Transmission type screen and rear projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission type screen that is able to emit a sharp image even in the case of having a curved surface.SOLUTION: A transmission type screen 10 in which a plurality of layers, by which image light made incident on from an incident light surface side is transmitted to an emission light surface side, are arranged one on the other comprises: a Fresnel lens sheet 21 with a Fresnel lens part 23; and a laminate body 11 arranged on the emission light side of the Fresnel lens sheet. The Fresnel lens sheet and the laminate body are arranged so as to have a curved surface. The laminate body includes an optical function layer 13 having: light transmission parts 14 arranged with a predetermined space between them along a screen surface and made of a material that transmits light; and a light absorption part 15 arranged between the adjacent light transmission parts and formed so as to be able to absorb light by containing light absorption material. Light diffusion particles 14b are dispersed in the light transmission parts 14.

Description

  The present invention relates to a transmissive screen having a curved surface for transmitting image light projected from the back side to an observer side, and a rear projection display device including the transmissive screen.

  As one of display devices that display video and images, there is a rear projection display device. This rear projection display device is also referred to as a rear projection display device, and is a display device that projects image light from an image light source on the back side of a transmissive screen and emits an image on the front side (observer side) of the screen. . The transmissive screen provided in the rear projection display device is equipped with a Fresnel lens sheet, a light diffusion sheet, etc. so that an observer can observe the image light from the image light source as an appropriate and high-quality image when emitted to the front side. It has been.

  Japanese Patent Application Laid-Open No. H10-228867 further discloses a technique that provides an excellent appearance by having a three-dimensional curved surface. This also describes that a transparent plate mixed with light diffusing particles is disposed on the light output side of the Fresnel lens.

JP 2012-032513 A

  However, with such a transmission screen, it is possible to widen the viewing angle, but when image light is provided, there is a problem that the image is blurred and the sharpness is lowered. Furthermore, since the light-emitting surface is a curved surface, this problem is sometimes promoted.

  In view of the above problems, an object of the present invention is to provide a transmission screen that can emit a clear image even if it has a curved surface. A rear projection display device including the transmission screen is also provided.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  The invention according to claim 1 is a transmission type screen (10) in which a plurality of layers for transmitting image light incident from the light incident surface side to the light output surface side are laminated, and the Fresnel lens portion (23) is provided. A Fresnel lens sheet (21) having a laminate (11) disposed on the light output side of the Fresnel lens sheet, the Fresnel lens sheet and the laminate are curved so as to have a curved surface, A light-transmitting portion (14) formed of a light-transmitting sheet-like base material layer (12) and a material that transmits a plurality of light arranged at predetermined intervals along the surface of the base material layer And an optical function layer (13) that is disposed between adjacent light transmission portions and that is formed so as to be capable of absorbing light by containing a material that absorbs light. The light diffusing particles (14b) are dispersed in the part , A transmission type screen.

  According to a second aspect of the present invention, in the transmissive screen (10) according to the first aspect, light scattering is also performed between the base layer side end of the light absorbing portion (15) and the base layer (12). Sites in which the particles (14b) are dispersed are provided.

  According to a third aspect of the present invention, in the transmissive screen (10) according to the first or second aspect, the light transmissive portion (14) is provided with a dimming function for reducing the intensity of incident light and emitting the light. Yes.

  According to a fourth aspect of the present invention, in the transmissive screen (10) according to any one of the first to third aspects, the light diffusing particles (14b) are included in the light transmissive portion and protrude from the surface of the light transmissive portion. Absent.

  According to a fifth aspect of the present invention, there is provided a rear projection display comprising: the transmissive screen according to any one of the first to fourth aspects; and an image light source (3) disposed on the back side of the transmissive screen. Device (1).

  According to the present invention, the appearance is excellent by having a curved surface, and the sharpness of the provided image light can be improved even if the curved surface is provided.

It is a figure explaining one embodiment, and is a figure showing notionally the structure of the rear projection display device. It is a perspective view of a transmissive screen. It is sectional drawing explaining the layer structure of a transmissive screen. It is the figure which expanded and showed a part of optical function layer. It is a rear view of the transmission type screen explaining a Fresnel lens part. It is the figure which showed one scene of the preparation methods of an optical function layer. It is the figure which showed the other scene of the preparation methods of an optical function layer. It is a figure explaining the example of the optical path of the conventional transmissive screen.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings shown below, the size and ratio of members may be exaggerated for easy understanding. Moreover, the code | symbol which becomes repeated may be abbreviate | omitted for legibility.

  FIG. 1 is a diagram for explaining one embodiment, and is a diagram conceptually showing a part of the internal structure of a rear projection display device 1 (hereinafter sometimes referred to as “display device 1”). is there.

The display device 1 includes a transmissive screen 10, and the video light I emitted from the video light source 3 is provided to the viewer through the transmissive screen 10. For example, the display device 1 is built in a dashboard portion of an automobile, and the viewer side surface of the transmissive screen 10 is disposed so as to be exposed in the vehicle, and provides an image to the viewer.
As can be seen from FIG. 1, the display device 1 includes a housing 2, an image light source 3, and a transmissive screen 10. In addition, although illustration is omitted, the display device 1 includes various components for functioning as a display device.

  The housing 2 is a member that forms an outer shell of the display device 1 and that accommodates most of the members constituting the display device 1 therein. Moreover, the housing | casing 2 has an opening so that the transmissive screen 10 can be supported, and the transmissive screen 10 is fitted and attached to this opening.

The image light source 3 is disposed in the housing 2 and irradiates the image light on almost the entire light incident surface of the transmission screen 10 as diverging light whose irradiation area gradually expands. As such an image light source 3, a conventionally known light source, for example, a single tube type light source using DMD can be used. In the present embodiment, the image light source 3 is disposed below the center of the transmissive screen 10 on the back side (the side opposite to the observer side) of the transmissive screen 10.
Here, the light incident surface of the transmissive screen 10 means a surface of the transmissive screen 10 on the side where the image light source 3 is disposed. On the other hand, the light exit surface of the transmissive screen 10 means a surface directed toward the observer side.

Next, the transmission screen 10 will be described. 2 is a perspective view of the transmission screen 10, and FIG. 3 is a cross-sectional view in the thickness direction of the transmission screen 10 in the vertical direction along the line indicated by III-III in FIG. It is. As can be seen from FIGS. 1 and 2, the transmission screen 10 has a plate-like shape as a whole, but is formed in a convex curved surface whose center protrudes toward the viewer. Accordingly, it is possible to provide a screen having an excellent appearance and a display device including the screen. Note that FIG. 3 should be originally curved, but for the sake of clarity, the curve is omitted and is flat.
In the present embodiment, the transmission screen 10 having a curved surface convex toward the viewer will be described. However, the convex direction is not limited to this, and is convex toward the back (that is, concave when viewed from the viewer). There may be. Further, the direction of the unevenness may be changed depending on the part by one transmission type screen.
As can be seen from FIGS. 2 and 3, the transmission screen 10 has a plurality of layers laminated, and the laminate 11 and the Fresnel lens sheet 21 are arranged in the thickness direction. This will be described in detail below.

  The laminate 11 includes a base material layer 12, an optical function layer 13, and a hard coat layer 16, which are laminated.

  The base material layer 12 is a layer that becomes a base material for forming the optical functional layer 13. Therefore, the base material layer 12 has translucency, and should just have intensity | strength to such an extent that the optical function layer 13 can be formed and hold | maintained. Examples thereof include films of polycarbonate, cycloolefin, TAC (Triacetylcellulose), and the like. Among these, polycarbonate is preferable from the viewpoint of availability and cost. The polycarbonate used herein is one having polycarbonate as a main polymer, and may include, for example, a filler such as a deterioration inhibitor, a plasticizer, and a softener, or a composite with a methacrylic resin or the like.

  The optical functional layer 13 is a layer having a function of controlling the optical path of the image light incident from the image light source side and improving the quality of the image light provided by appropriately absorbing stray light and external light. The optical functional layer 13 has a shape that has the cross section shown in FIG. 3 and extends to the back / near side of the drawing. FIG. 4 shows an enlarged part of the optical functional layer 13 shown in FIG.

  The optical functional layer 13 is arranged in parallel along one surface of the base material layer 12 so that light can be transmitted between a plurality of light transmission parts 14 arranged in parallel so that light can be transmitted and between two adjacent light transmission parts 14. The light transmitting portion 14 and the light absorbing portion 15 have the shapes shown in FIGS. 3 and 4 and extending in the back / near side of the drawing. ing. That is, in this embodiment, the light transmission part 14 and the light absorption part 15 are extended in the horizontal direction, and the some light transmission part 14 and the light absorption part 15 are paralleled in the vertical direction.

  The light transmission portion 14 is a part having a function of transmitting image light, and is an element having a substantially trapezoidal cross section in the cross sections shown in FIGS. 3 and 4. The upper base and the lower base longer than the upper base in the substantially trapezoidal cross section are arranged in a direction along the layer surface of the optical functional layer 13. In this embodiment, an upper base is disposed on the observer side, and a lower base is disposed on the image light source side.

In the light transmission part 14, light diffusion particles 14b are dispersed in a binder 14a.
The binder 14a is formed of a light-transmitting material that holds the light diffusion particles 14b in a dispersed state and has a refractive index of Np. If it is such a material, it will not specifically limit. The value of the refractive index Np is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of the availability of the applied material. As a material constituting the binder 14a, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., an epoxy acrylate or urethane acrylate reactive resin (ionizing radiation curable type) Resin).

The light diffusion particles 14b are particulate members dispersed in the binder 14a. The light diffusing particles 14b diffuse light due to a difference in refractive index with the binder 14a or due to the reflectivity of the light diffusing particles themselves. As the light diffusing particles, organic fillers such as plastic beads can be preferably applied, and those having high transparency are particularly preferable. Examples of the plastic beads include melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, and vinyl chloride beads. Among these, acrylic beads are preferable. When no resin is used, glass beads or bubbles can be used.
Here, it is preferable that the light diffusion particles 14b are included in the binder 14a and do not protrude from the surface. This is a form of light diffusion by so-called internal diffusion, and internal diffusion is easier to control light than external diffusion using surface irregularities. Further, as will be described later along with an example of an optical path, according to internal diffusion, necessary light can be selectively advanced each time the image light travels, and a clear image light can be provided efficiently. Furthermore, from the viewpoint of manufacturing, the surface can be easily laminated on other layers by having no irregularities.

The light absorbing portion 15 is an element that is disposed between the adjacent light transmitting portions 14 and has a substantially trapezoidal shape in the cross section shown in FIGS. 3 and 4. The upper base and the lower base longer than the upper base in the substantially trapezoidal cross section are arranged in a direction along the layer surface of the optical functional layer 13. In this embodiment, a lower base is disposed on the viewer side, and an upper base is disposed on the image light source side.
Here, it is preferable that the hypotenuse (leg part) in the substantially trapezoidal cross section of the light absorption part 15 forms an angle of 0 degrees or more and 10 degrees or less with respect to the normal direction of the layer surface of the optical function layer 13. Note that when the angle of the hypotenuse is close to 0 degrees, the cross section of the light absorbing portion 15 is substantially rectangular. In addition, the slope of the oblique side of the light absorbing portion 15 is not necessarily constant, and may be a polygonal line that changes depending on the position of the optical function layer 13 in the thickness direction, or may be a curved line. Further, the length of the upper base of the light absorbing portion 15 can be reduced to make the cross section substantially triangular.

In the light absorbing portion 15, light absorbing particles 15b are dispersed in a binder 15a.
The binder 15a is formed of a light-transmitting material that holds the light diffusion particles 15b in a dispersed state and has a refractive index of Nb. If it is such a material, it will not specifically limit. As a material constituting the binder 15a, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., an epoxy acrylate or urethane acrylate reactive resin (ionizing radiation curable type) Resin).
The size of the refractive index Nb is preferably Np or less. When Nb is smaller than Np, it is possible to cause total reflection based on the refractive index difference and the incident angle at the interface between the light transmitting portion 14 and the light absorbing portion 15, deflecting the image light toward the viewer side, and bright image light Can be provided. The difference in refractive index between Np and Nb is not particularly limited, but is preferably 0 or more and 0.06 or less. The value of the refractive index Nb is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of the availability of the material to be applied.

As the light absorbing particles 15b, light absorbing colored particles such as carbon black can be preferably used. However, the present invention is not limited to this, and colored particles that selectively absorb a specific wavelength in accordance with the characteristics of the image light may be used. Specific examples include organic fine particles colored with metal salts such as carbon black, graphite, and black iron oxide, dyes, pigments, colored glass beads, and the like. In particular, colored organic fine particles are preferably used from the viewpoints of cost, quality, availability, and the like. More specifically, acrylic cross-linked fine particles containing carbon black, urethane cross-linked fine particles containing carbon black, and the like are preferably used.
The average particle diameter of the light absorbing particles is preferably 1.0 μm or more and 20 μm or less.

  With the configuration of the optical functional layer 13 as described above, the sharpness of the provided image light can be improved. Details will be described later.

  In the optical function layer 13 described above, a light reduction function may be further added to the light transmission portion 14. This is a function as a so-called Tint layer. Such a light reduction function can be exhibited by making the toning pigment turbid in the binder 14a.

  As the toning dye, a known dye having a maximum absorption wavelength in the visible region of 380 nm to 780 nm can be used in combination with any dye according to the purpose. Known dyes that can be used as toning dyes include the dyes described in JP 2000-275432 A, JP 2001-188121 A, JP 2001-350013 A, JP 2002-131530 A, and the like. Can be suitably used. In addition, other dyes such as anthraquinone, naphthalene, azo, phthalocyanine, pyromethene, tetraazaporphyrin, squarylium, and cyanine that absorb visible light such as yellow light, red light, and blue light. Can be used.

  Thus, if the light transmission part 14 is provided with a light reduction function, a new layer for that purpose is not required, so the number of layers can be reduced, and a thinner transmissive screen 10 can be provided.

  Furthermore, in the optical functional layer 13, as shown by the part 14c in FIG. It is preferable that the site | part which has the same structure is provided. That is, the binder 14a in which the light diffusion particles 14b are dispersed is disposed closer to the image light source 3 (base material layer 12) than the end of the light absorption portion 15 on the base material layer 12 side. Thereby, as will be described later, it is possible to emit image light that has been absorbed by the light absorption unit 15 to the observer.

Returning to FIG. 3, the hard coat layer 16 will be described. The hard coat layer 16 is a layer provided on the outermost surface on the viewer side of the transmissive screen 10 for the purpose of surface protection. The hard coat layer 16 can be formed as a transparent resin layer, and is preferably formed as a cured resin layer formed by curing a curable resin from the viewpoint of resistance to scratches and surface contamination.
Specifically, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to the required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins. For example, acrylate-based ionizing radiation curable resins include monofunctional (meth) acrylate monomers, bifunctional (meth) acrylate monomers, (meth) acrylate monomers such as trifunctional or higher (meth) acrylate monomers, urethane (meta ) Acrylate, epoxy (meth) acrylate, polyester (meth) acrylate and other (meth) acrylate ester oligomers or (meth) acrylate ester prepolymers. Examples of tri- or higher functional (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

Further, the hard coat layer 16 may be added with a function of improving the stain resistance. This can be achieved, for example, by adding a silicone compound, a fluorine compound, or the like. Further, as other functions, it may have a function of improving antistatic properties and water repellency.
As materials that can be used for improving the antistatic property, PEDOT-PSS (PEDOT (Poly (3,4-ethylenedioxythiophene); 3,4-ethylenedioxythiophene polymer) and PSS (polynesulfonate) are used for the electron conduction type. ); A styrene sulfonic acid polymer)), and the ionic conductive type includes lithium salt materials.
Examples of materials that can be used to improve water repellency include fluorine compounds.

  Next, the Fresnel lens sheet 21 will be described. The Fresnel lens sheet 21 includes a base portion 22, a Fresnel lens portion 23 formed on the surface of the base portion 22, and an incident-side transparent base material layer 24. FIG. 5 schematically shows a form when the transmission screen 10 is viewed from the front in order to explain the Fresnel lens portion 23.

  The base portion 22 is a layer that serves as a base for forming the Fresnel lens portion 23. Therefore, the base portion 22 has translucency, and it is sufficient that the base portion 22 is strong enough to form and hold the Fresnel lens portion 23. For this, for example, the same material as that of the base material layer 12 described above can be used.

  The Fresnel lens unit 23 has a function of deflecting the traveling direction of the image light projected from the image light source 3 onto the transmissive screen 10 as a divergent light beam. Specifically, the Fresnel lens unit 23 converts the image light incident as a divergent light beam into a parallel light beam traveling from the image light incident side toward the image light emitting side, for example, a parallel light beam traveling in the front direction. As described above, once the image light is collimated once using the Fresnel lens unit 23, the inner surface variation of the brightness of the image observed by the observer, in particular, the image observed from the oblique direction by the observer is reduced. Can be effectively mitigated.

As can be seen from FIG. 5, the Fresnel lens portion 23 of the present embodiment is a so-called circular Fresnel lens. Therefore, the longitudinal direction of each of the plurality of unit lenses 23a extends in an arc shape having a predetermined radius, and is arranged so as to form a concentric circle with the adjacent unit lenses 23a. As the cross-sectional shape of each unit lens 23a, a known one can be used as appropriate according to the purpose.
In the present embodiment, the unit lens 23a is symmetrical with respect to the vertical direction line A passing through the center position in the horizontal direction with respect to the horizontal direction. On the other hand, with respect to the vertical direction, the center O of the concentric circle in which the unit lenses 23a are arranged is below the transmission screen 10 on the vertical direction line A. In this way, by decentering the center O from the center of the Fresnel lens portion 23 in the vertical direction, even if image light is projected from below the transmission screen 10, the divergent light beam from the image light source 3 is efficiently converted into a parallel light beam. can do. Further, with the configuration in which the image light is irradiated from below the transmission screen in this way, the image light source 3 can be brought closer to the observer side, and the display device 1 can be made thin.

  However, the present invention is not limited to this, and a circular Fresnel lens in which the center of the concentric circle exists in the Fresnel lens portion or a plurality of unit lenses in a direction different from the direction in which the unit lens extends horizontally or vertically linearly. It does not preclude the application of a linear Fresnel lens in which is arranged.

As resin which comprises the Fresnel lens part 23, transparent resins, such as an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, an acryl-styrene copolymer resin, can be mentioned.
When the size of the transmission screen 10 is large, epoxy acrylate or urethane acrylate reactive resin (ionizing radiation curable resin or the like) can be used from the viewpoint of moldability.

  The incident side transparent base material layer 24 is configured to prevent the Fresnel lens sheet 21 from being deformed and to support the Fresnel lens sheet 21. From this point of view, specific examples of the material forming the incident-side transparent base material layer 24 include an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, and an acrylic-styrene copolymer resin. Moreover, it is preferable that the thickness of the incident side transparent base material layer 24 is 1 mm-3 mm. If the incident-side transparent base material layer 24 is less than 1 mm, the rigidity may be insufficient. On the other hand, if the incident-side transparent base material layer 24 is thicker than 3 mm, there is a high possibility that an image is defective.

The transmission screen 10 described above can be manufactured as follows, for example.
The Fresnel lens sheet 21 can be produced by a known method. For example, the Fresnel lens part 23 can be molded on the base part 22. Moreover, the base material layer 12, the hard-coat layer 16, and the incident side transparent base material layer 24 are each a smooth sheet form, and can be obtained by a well-known method.

The method for producing the optical functional layer 13 is not particularly limited, but can be obtained, for example, as follows. FIG. 6 and FIG. 7 are diagrams for explanation.
As shown in FIG. 6, the light transmission portion 14 is formed on the base material 12 ′ that first becomes the base material layer 12 or includes the layer that becomes the base material layer 12. In order to form the light transmitting portion 14, a mold roll 42 having grooves having a shape corresponding to the shape of the light transmitting portion 14 at a predetermined pitch is prepared. Next, the base material 12 ′ is fed between the mold roll 42 and the nip roll 41. An arrow VI shown in FIG. 6 is a direction in which the substrate 12 ′ is fed. In accordance with the feeding of the base material 12 ′, the droplets of the composition 40 constituting the light transmission portion are continuously supplied from the supply device 45 between the mold roll 42 and the base material 12 ′. When the composition 40 is supplied from the supply device 45 onto the base material 12 ′, a bank in which the composition 40 is accumulated is formed between the mold roll 42 and the base material 12 ′. In this bank, the composition 40 spreads in the width direction of the substrate 12 ′.

  The composition 40 supplied between the mold roll 42 and the base material 12 ′ as described above is caused by the pressing force between the mold roll 42 and the nip roll 41 between the base material 12 ′ and the mold roll 42. Filled in between. Thereafter, the light transmitting unit 14 can be formed by irradiating the composition 40 with ultraviolet rays or the like by the light irradiation device 44 and curing the composition 40. After the light transmissive part 14 is formed, the sheet on which the light transmissive part 14 is formed on the base material 12 ′ is pulled through the peeling roll 43 to be peeled off from the mold roll 42.

  Next, the light absorption part 15 is formed between the light transmission parts 14 of the sheet obtained through the process shown in FIG. Specifically, as shown in FIG. 7, the composition 46 constituting the light absorbing portion is supplied onto the light transmitting portion 14, and the composition 46 is put into the groove 14 ′ between the light transmitting portions 14 by the doctor blade 47. While filling, surplus composition 46 is scraped off. The light absorption part 15 can be formed by irradiating the composition 46 remaining in the groove 14 ′ between the light transmission parts 14 with ultraviolet rays or the like to cure. In this way, the optical functional layer 13 is formed on the base material layer 12. Note that an arrow VII shown in FIG. 7 is a sheet feeding direction.

The lamination of the layers obtained as described above can be fixed to each other by fusion or via an adhesive layer. In the transmissive screen 10, the optical functional layer 13 and the hard coat layer 16, and the base 22 and the incident side transparent base material layer 24 are fixed with an adhesive or the like.
The material of the adhesive is not particularly limited as long as it transmits light and has appropriate adhesiveness. Examples thereof include an acrylic pressure-sensitive adhesive.
Further, the adhesion may be performed by an ultraviolet curable resin.

  Here, when bonding each layer, each sheet is curved in advance. The method for bending each layer is not particularly limited. For example, each sheet is heated and softened to a temperature higher than the glass transition point, and cooled after being placed along a mold for bending the sheet. be able to.

  According to the display device 1 including the transmission screen 10 described above, it is possible to provide image light to an observer as follows, for example. An explanation will be given while showing an example of an optical path. However, the optical path examples shown here are conceptual and do not strictly represent reflection angles, refraction angles, or the like.

As shown in FIG. 1, the image light L <b> 1 emitted from the image light source 3 reaches the light incident surface side of the transmissive screen 10.
The image light that has reached the light incident surface side of the transmission screen 10 in this way is, as indicated by image light L31 in FIG. 3, the observer side (front direction) by the action of the Fresnel lens portion 23 of the Fresnel lens sheet 21. ) To be parallel to ().

The image light deflected in the Fresnel lens sheet 21 passes through each layer and reaches the optical function layer 13. In the optical function layer 13, the image light is emitted to the viewer side while being deflected by the light diffusion particles 14b as indicated by the image light L41 and L42 in FIG.
The direction of the image light L41 is changed by the light diffusion particles 14b, and the image light is emitted in a direction slightly widening the viewing angle with respect to the front.
In the image light L42, the image light whose direction is changed by the light diffusion particles 14b reaches the interface between the light transmission unit 14 and the light absorption unit 15. In this example, since there is a difference in refractive index between the light transmitting portion 14 and the light absorbing portion 15, if the total reflection condition is satisfied and the light enters the interface, the light is totally reflected here and emitted to the viewer side. At this time, if the interface is inclined at a predetermined angle as described above, total reflection is performed in a direction that further widens the viewing angle.
Further, the image light indicated by the image light L43 in FIG. 4 is image light that is incident on the image light source 3 side (the substrate layer 12 side, that is, the portion 14c) from the end of the light absorbing unit 15 on the substrate layer 12 side. Yes, according to the conventional example, it is absorbed by the light absorbing portion 15 as it is. However, in this embodiment, since the light diffusion particles 14b are dispersed here, the image light L43 is also deflected and emitted to the observer. Therefore, a brighter image can be provided to the observer.

  Further, the image light indicated by the image light L44 in FIG. 4 is reflected by the light diffusing particles 14b, finally enters the light absorbing portion 15, and is absorbed by the light absorbing particles 15b. If such image light is emitted to the viewer side, the image light has an angle that is emitted with a wider viewing angle than necessary. Therefore, the image light may affect other image light, resulting in blurring of the image light. There is. Therefore, the optical functional layer 13 can appropriately absorb this.

  On the other hand, as indicated by the light L32 in FIG. 3, a part of the external light (light from sunlight, room light, etc.) incident on the transmission screen 10 from the observer side is incident on the light absorbing portion 15. It is absorbed by the light absorbing particles 15b. As a result, the influence of external light on the image light can be reduced, and the contrast can be improved.

As described above, according to the transmissive screen 10, the light diffusion particles 14 b are disposed between the light absorption portions 15 by dispersing the light diffusion particles 14 b in the light transmission portion 14. That is, the light diffusing particles, which are a medium having a light diffusing function, are arranged so as to be dispersed both in the thickness direction and in the surface direction of the light transmitting portion.
Thereby, it is possible to prevent the light diffused by the light diffusing particles 14b from diffusing more than necessary, while the light diffusing particles 14b diffuse the light to widen the viewing angle. The light diffused more than necessary is absorbed by the light absorber 15 as shown in the video light L44 and is not provided to the observer. Since such image light affects other image light and reduces the clarity of the image light, a clear image can be provided by absorbing it.

For example, as in the conventional example shown in FIG. 8, when a layer containing light diffusing particles is separately provided and disposed on the viewer side, an image is displayed in a wider viewing angle direction than necessary, such as the image light L81. Since the light is emitted and affects other image light such as the normal image light L82, the sharpness of the image light is deteriorated. In particular, when the light exit surface is a curved surface, the exit angle may further spread outward, which may increase the reduction in sharpness.
In the present invention, as described above, such light can be appropriately absorbed by the light absorption unit 15, so that clear image light can be provided.

  If the light diffusing particles 14b are encapsulated in the binder 14a and dispersed, the light diffusing particles 14b are dispersed along the thickness direction of the light transmitting portion, which is the basic traveling direction of light. In addition, the light is sequentially diffused in the process of transmitting the image light through the light transmitting portion, so that the light that should not be emitted can be absorbed each time, and the light that should be emitted can be selectively advanced to the viewer side. It is possible to emit high quality video light efficiently.

1 Rear projection display device (display device)
DESCRIPTION OF SYMBOLS 2 Case 3 Image | video light source 10 Transmission type screen 11 Laminated body 12 Base material layer 13 Optical function layer 14 Light transmission part 14b Light diffusion particle 15 Light absorption part 15b Light absorption particle 16 Hard coat layer 21 Fresnel lens sheet 22 Base 23 Fresnel lens Part 24 Incident-side transparent substrate layer

Claims (5)

A transmission type screen in which a plurality of layers that transmit image light incident from the light incident surface side to the light output surface side are laminated,
A Fresnel lens sheet having a Fresnel lens part;
A laminate disposed on the light output side of the Fresnel lens sheet,
The Fresnel lens sheet and the laminate are curved to have a curved surface,
The laminate is
A sheet-like base material layer having translucency;
A light transmission part formed of a material that transmits a plurality of light having a predetermined interval along the surface of the base material layer;
A light absorbing portion that is disposed between the adjacent light transmitting portions and that is formed so as to be able to absorb light by containing a material that absorbs light, and an optical functional layer comprising:
A transmissive screen in which light diffusing particles are dispersed in the light transmissive portion.   The transmissive screen according to claim 1, further comprising a portion where light scattering particles are dispersed between the base layer side end of the light absorbing portion and the base material layer.   The transmissive screen according to claim 1, wherein the light transmissive portion is provided with a dimming function that emits light with reduced intensity of incident light.   The transmissive screen according to claim 1, wherein the light diffusing particles are included in the light transmissive portion and do not protrude from the surface of the light transmissive portion. The transmissive screen according to any one of claims 1 to 4,
A rear projection display device comprising: an image light source disposed on a back side of the transmissive screen.

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