JP2012252097A - Reflective screen and reflective projection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective screen capable of improving contrast even when a distance from an image source is short, and to provide a reflective projection system having the reflective screen.SOLUTION: The reflective screen comprises: from the side where image light is projected, an optical functional layer; a Fresnel lens layer; and a light-reflecting layer formed on a lens face of the Fresnel lens layer. The optical functional layer comprises: light-transmitting portions arranged in parallel to one another to transmit light; and light-absorbing portions formed between the light-transmitting portions to absorb light, in which the refractive index of the light-transmitting portion is equal to or lower than the refractive index of the light-absorbing portion. On a cross-sectional view in a layer thickness direction of the screen in such a posture that the arrangement direction of the light-absorbing portions is aligned to the vertical direction, one of an upper interface and a lower interface of the light-absorbing portion with the light-transmitting portion is formed based on an incident direction of image light that is estimated to enter the optical functional layer; and the other interface is formed based on an incident direction of light, except for the image light, estimated to enter the optical functional layer. The reflective projection system includes the reflective screen.

Description

  The present invention relates to a reflective screen that enables observation by reflecting light projected from an image source, and a reflective projection system including the reflective screen.

  The reflection type screen is a screen for reflecting the light from an image source such as a projector and emitting it to the viewer side and providing the image light. In such a reflection type screen, various techniques have been disclosed so far in order to satisfy the demand for obtaining an image with high contrast and the requirement for obtaining an image with the highest possible brightness. For example, Patent Literature 1 includes a light transmission portion arranged in parallel so as to transmit light in a cross section orthogonal to the screen surface, and a cavity formed between the light transmission portions, and the back surface of the light transmission portion. A reflective screen is disclosed in which a reflective portion for reflecting light is formed on the side, and a light absorbing layer for absorbing light is formed on the back side of the cavity and the reflective portion. Further, in Patent Document 2, in a cross section orthogonal to the screen surface, a light transmission part that transmits light, a light absorption part that absorbs light, and at least a back surface side of the light transmission part are provided. A light-reflecting layer that reflects light that has passed through the light-transmitting portion. The light-transmitting portion and the light-absorbing portion are alternately arranged along the screen surface, and the light-transmitting portion is orthogonal to the screen surface. A reflective screen is disclosed in which the shape in cross section changes depending on the position in the direction along the screen surface.

JP 2010-204572 A JP 2008-39901 A

  According to the reflection type screens disclosed in Patent Document 1 and Patent Document 2, it is considered that an image with high contrast can be obtained. However, in the conventional reflection type screen, when an image source is arranged at a position close to the screen (for example, a position within 1 m from the reflection type screen) and image light is projected from an oblique direction, the reflection type from the image source is reflected. The incident angle of light projected on the screen is increased, and it is difficult to appropriately guide the image light within the reflective screen and reflect it to the viewer side.

  Therefore, an object of the present invention is to provide a reflective screen that can improve the contrast even when the distance to the image source is short, and a reflective projection system including the reflective screen.

  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 reflective screen (10) that can be viewed by reflecting the image light (VL) projected from the image source (2), from the side on which the image light is projected, An optical functional layer (12, 12 '), a Fresnel lens layer (23), and a light reflecting layer (24) formed on the lens surface of the Fresnel lens layer, the optical functional layer being capable of transmitting light The light transmission part (13) arranged in parallel and the light absorption part (14, 14 ') formed so that light can be absorbed between this light transmission part is provided, and the refractive index of a light transmission part is a light absorption part. In the cross-sectional view in the layer thickness direction in a posture in which the parallel direction of the light absorbing portions is the vertical direction, the upper interfaces (14b, 14b ′) among the interfaces with the light transmitting portions of the light absorbing portions. ) And the lower interface (14a, 14a ') are assumed to be incident on the optical functional layer. Is formed on the basis of the incident direction of the light, the other is formed on the basis of the incident direction of light other than image light is supposed to enter the optical functional layer is a reflective screen.

  In the present invention, “comprising an optical functional layer, a Fresnel lens layer, and a light reflecting layer formed on the lens surface of the Fresnel lens layer from the side on which the image light is projected” means that the image light is projected. This means that at least an optical functional layer, a Fresnel lens layer, and a light reflecting layer are provided from the side to be provided, and another layer may be provided between these layers or on the surface.

  According to a second aspect of the present invention, in the reflective screen (10) according to the first aspect, in the posture in which the parallel direction of the light absorbing portions (14, 14 ') is a vertical direction, the arrangement position of the light absorbing portion is The higher the height, the larger the angle of the lower interface (14a, 14a ′) with respect to the horizontal plane among the interface between the light absorbing part and the light transmitting part.

  According to a third aspect of the present invention, in the reflective screen (10) according to the first or second aspect, the light absorbing portion is arranged in a posture in which the parallel direction of the light absorbing portions (14, 14 ') is a vertical direction. As the position is lower, the upper interfaces (14b, 14b ′) of the interfaces between the light absorbing section and the light transmitting section are closer to the horizontal.

  A fourth aspect of the invention includes a reflective screen (10) according to any one of the first to third aspects, and a video source (2) for projecting video light onto the reflective screen. This is a mold projection system (1).

  According to a fifth aspect of the present invention, in the reflective projection system (1) according to the fourth aspect, the horizontal direction from the light exit surface of the image source (2) to the surface on the viewer side of the reflective screen (10). The distance is 1 m or less.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the distance with an image source is near, a reflective screen which can improve contrast, and a reflective projection system provided with this reflective screen can be provided.

It is sectional drawing which shows schematically the reflection type projection system concerning one Embodiment. 2 is a diagram schematically showing an enlarged part of an optical functional layer provided in the reflective screen 10. FIG. FIG. 3A and FIG. 3B are cross-sectional views illustrating the specific shape of the light absorbing portion. It is a figure which shows typically an example of the process of forming the light transmission parts 13, 13, .... It is sectional drawing which shows schematically the optical function layer 12 'concerning other embodiment, and is a figure equivalent to FIG. It is a figure explaining the method of producing optical function layer 12 '. FIG. 3 is a diagram illustrating an example of an optical path of image light that is enlarged on a part of the Fresnel lens layer and is incident on the Fresnel lens layer. 3 is a plan view schematically showing a Fresnel lens layer 23. FIG.

  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. Each drawing is simplified by changing the scale and the like as appropriate for convenience of illustration and understanding. Moreover, in each drawing, the same code | symbol is attached | subjected to the thing of the same structure, and the code | symbol which becomes repeated may be abbreviate | omitted partially.

<Reflective projection system 1>
FIG. 1 is a cross-sectional view schematically showing a reflective projection system 1 according to one embodiment. As can be seen from FIG. 1, the reflective projection system 1 includes an image source 2 and a reflective screen 10. Each will be described below.

  The image source 2 is a device that projects image light toward the reflective screen 10, and a known projector can be used. As can be seen from FIG. 1, in the present embodiment, the video source 2 projects image light toward the reflective screen 10 from below the center of the screen of the reflective screen 10.

The reflection type screen 10 is a rectangular thin sheet as a whole, and is installed such that the sheet surface is unfolded during use and the sheet surface is erected in the vertical direction. In order to ensure the flatness of the reflective screen 10 in use, it is preferable that the reflective screen 10 be attached to a support means (not shown) having a predetermined rigidity with an adhesive or the like. The support means may be a plate or a sheet-like member, but is not particularly limited as long as the posture of the reflective screen 10 can be maintained. Further, when not in use, it may be made compact by winding in a roll.
The reflective screen 10 functions as a screen by reflecting the image light projected from the image source 2 toward the viewer A (see FIG. 1).

  As will be described later, according to the reflective screen 10, the contrast of the video displayed on the screen surface can be improved even when the distance between the video source 2 and the reflective screen 10 is short. Therefore, the horizontal distance between the light exit surface of the video source 2 and the surface on the viewer side of the reflective screen 10 can be within 1 m. For example, when an ultra-short projection distance front projector CP-A100J (manufactured by Hitachi, Ltd.) is used, an 80-inch image can be displayed from a distance of 0.63 m.

<Reflective screen 10>
Next, the reflective screen 10 will be described with reference to the drawings. The reflective screen 10 shown in FIG. 1 includes a hard coat layer 21, an optical functional layer 12, a base material layer 11, a diffusion layer 22, a Fresnel lens layer 23, and a reflective layer 24 in this order from the image source 2 side. ing. Hereinafter, these layers will be described in detail.

(Base material layer 11)
The base material layer 11 is a sheet-like member serving as a base material for forming the optical functional layer 12, and is formed with high translucency. Although the material which comprises the base material layer 11 is not specifically limited, Polyethylene terephthalate (PET), a polycarbonate (PC), methylmethacrylate butadiene styrene (MBS), an acrylic type, a triacetyl cellulose (TAC) etc. Each resin can be mentioned. MBS is preferably used from the viewpoints of availability, ease of handling, formability, and price.

  Here, the base material layer 11 may have other functions while having translucency. For example, a light scattering material can be mixed in order to enlarge the viewing angle or improve the uniformity of in-plane luminance. In addition, pigments and dyes are used to correct color tone or to absorb a part of light other than image light (hereinafter, light other than image light is sometimes referred to as “external light”) to improve contrast. May be mixed.

(Optical function layer 12)
As will be described in detail later, the optical functional layer 12 is a layer that contributes to improving the contrast of an image displayed on the reflective screen 10 by transmitting image light while absorbing external light. The optical functional layer 12 has a shape that has the cross section shown in FIG. 1 and extends to the back / near side of the drawing. That is, in the cross section shown in FIG. 1, the optical functional layer 12 is formed so as to be able to absorb light between the light transmission portions 13, 13,. .. Are provided. In FIG. 2, a part of the optical functional layer 12 is shown in an enlarged manner.

  The light transmitting portions 13, 13,... Are elements having a function of transmitting light, and are elements having a substantially rectangular cross section that is asymmetric in the vertical direction in the cross section shown in FIGS. In addition, the light transmitting portions 13, 13,... Have a refractive index of Np, and such light transmitting portions 13, 13,... Are configured by curing a light transmitting portion constituent composition that will be described later, for example. be able to. 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.

  Next, the light absorbers 14, 14,... Will be described. The light absorbing portions 14, 14,... Are portions having a function of absorbing light, and are disposed between the light transmitting portions 13, 13,. In addition, the light absorbing portion 14 has a substantially triangular cross section that is vertically asymmetric and has one apex on the light reflecting layer 24 side in a cross-sectional view orthogonal to the extending direction. The base 14c in the substantially triangular cross section of the light absorbing portions 14, 14,... Is disposed in a direction along the layer surface on the viewer side of the optical function layer 12. In addition, although the figure has illustrated the form in which the light absorption part 14 has a substantially triangular cross section, the cross-sectional shape of a light absorption part may be a substantially trapezoid which lacked the top part of the substantially triangle.

  The light absorbing portions 14, 14,... Are made of a predetermined material having a refractive index Nb, and the refractive index Nb of the light absorbing portions 14, 14,... Is greater than or equal to the refractive index Np of the light transmitting portions 13, 13,. is there. In this way, by satisfying the relationship of Np ≦ Nb, the light that has reached the interface between the light transmitting parts 13, 13... And the light absorbing parts 14, 14,. It can absorb with the absorption parts 14,14, .... The difference between Np and Nb is not particularly limited.

  The shape of the light absorbing portion 14 will be described in further detail below. 1 and FIG. 2, that is, in the cross-sectional view in the layer thickness direction in a posture in which the parallel direction of the light absorbing portions 14, 14,... Of these, one of the upper interface 14 b and the lower interface 14 a is formed based on the incident direction of the image light that is assumed to be incident on the optical function layer 12, and the other is assumed to be incident on the optical function layer 12. It is formed based on the incident direction of light other than image light.

  The interface between the light absorbing portion 14 and the light transmitting portion 13 will be described more specifically below. In the embodiment illustrated in FIGS. 1 and 2, it is assumed that the video source 2 projects the video light VL from the lower side of the screen center of the reflective screen 10. Therefore, as shown in FIG. 2, the image light VL is incident on the optical functional layer 12 from obliquely below. On the other hand, many external lights OL such as fluorescent lamps and sunlight enter the optical functional layer 12 obliquely from above. Here, the lower interface 14a of the interfaces between the light absorbing section 14 and the light transmitting section 13 is formed based on the incident direction of the image light VL that is assumed to be incident on the optical function layer 12, and the upper interface 14b is It is formed based on the incident direction of the external light OL assumed to be incident on the optical function layer 12. That is, the interface 14a is formed such that the angle θ1 formed with the horizontal plane is close to the incident angle of the image light VL, and the interface 14b is formed at an angle that intersects the incident direction of the external light OL from obliquely above. Has been.

  As described above, by forming the angle θ1 formed by the interface 14a with the horizontal plane so as to be an angle close to the incident angle of the image light VL, the image light VL that has reached the bottom surface 14c of the light absorber 14 (arrow in FIG. 2). The image light VL incident on the region indicated by x1 is absorbed by the light absorbing unit 14, but most of the image light VL incident on the other region passes through the light transmitting unit 13 without reaching the interface 14a. It is not absorbed by the light absorber 14. As will be described later, the image light transmitted through the light transmission part 13 is reflected by the Fresnel lens layer 23 and the reflection layer 24 at different angles, so that the light passes through the light transmission part 13 again and is observed from the observer side. can do.

  Thus, in the optical function layer 12, by appropriately adjusting the angle of the interface 14a based on the incident angle of the image light VL, the image light VL is transmitted even when the incident angle of the image light VL is large, It can be led to the Fresnel lens layer 23 and the reflective layer 24. Therefore, even when the image source 2 is disposed near the reflective screen 10, an image can be displayed on the screen surface.

  On the other hand, by forming the interface 14b at an angle that intersects the incident direction of the external light OL from obliquely above, the external light OL that has reached the bottom surface 14c of the light absorbing portion 14 (incident in the region indicated by the arrow y1 in FIG. 2) In addition to the external light OL), the external light OL that has reached the interface 14b (external light OL that has entered the region indicated by the arrow y2 in FIG. 2) is also absorbed by the light absorber 14. Therefore, in the optical function layer 12, the ratio that the external light OL is absorbed by the light absorbing unit 14 is higher than the image light VL.

  As described above, according to the reflective screen 10, the light absorbing unit 14 can absorb a lot of external light OL obliquely above the image light VL, so that the contrast of the image displayed on the screen surface is increased. be able to. In addition, as described above, even if the distance between the image source 2 and the reflective screen 10 is reduced, the image light VL can be transmitted and the external light OL can be absorbed. Even when installed near the screen 10, the contrast of the image displayed on the screen surface can be increased.

  In order to allow more image light VL to pass through the light transmission part 13 without being absorbed by the light absorption part 14, in the posture shown in FIG. 1, the higher the arrangement position of the light absorption part 14, the higher the horizontal plane of the interface 14a. It is preferable to increase the angle with respect to. That is, in the posture shown in FIG. 1, it is preferable to increase θ1 as the arrangement position of the light absorbing portion 14 is higher. This is because when the image light VL is projected obliquely from below the reflective screen 10 as illustrated in FIG. 1, the higher the reflective screen 10 is, the larger the incident angle of the image light VL.

  On the other hand, in order to efficiently absorb more external light OL by the light absorption unit 14, the interface 14b may be made closer to the horizontal as the arrangement position of the light absorption unit 14 is lower in the posture illustrated in FIG. preferable. As illustrated in FIG. 1, when light incident from obliquely above the reflective screen 10 is assumed as the external light OL, it is considered that the incident angle of the external light OL increases as the reflective screen 10 is positioned lower. .

  As described above, in the reflective screen, the shape of the light absorbing portion provided in the optical functional layer greatly contributes to increase the contrast of the image displayed on the screen surface. In addition, the appropriate shape and arrangement of the light absorbing portion vary depending on the positional relationship between the reflective screen and the video source that projects the video light on the reflective screen. Accordingly, the size of the light absorption unit, the arrangement interval, the angle of the interface between the light absorption unit and the light transmission unit, and the like can be appropriately changed according to the positional relationship between the reflective screen and the image source.

  For example, the width x1 of the region where the image light reaching the bottom 14c of the light absorbing portion 14 is preferably 5 μm or more and 50 μm or less, and more preferably about 10 μm. On the other hand, the width x2 of the region where the image light that does not reach the base 14c is preferably 25 μm or more and 250 μm or less, and more preferably about 50 μm. In the plan view from the viewer side of the optical functional layer 12, the ratio of the light absorbing portions 14, 14,... Occupying the screen surface is preferably 2% or more and 50% or less, and about 20%. Is more preferable. θ1 is preferably 20 degrees or greater and 85 degrees or less, and more preferably 32.9 degrees or greater and 77 degrees or less. Here, when θ1 is 77 degrees, it is assumed that the light emitting surface of the image source is arranged at a horizontal distance of 269.9 mm and a height of 174.3 mm from the lower end of the image display surface of the reflective screen. Yes. A specific form in the case where θ1 is 32.9 degrees and 77 degrees is illustrated in FIG. FIGS. 3A and 3B are cross-sectional views illustrating specific shapes of the light absorbing portion. FIG. 3A illustrates a case where θ1 is 32.9 degrees, and FIG. Indicates a case where θ1 is 77.0 degrees. As described above, θ1 is preferably changed according to the arrangement position (distance from the video source) of the light absorption unit, and x1 and x2 are constant according to the incident angle of the video light. It is preferable that each light absorption part is formed.

  For example, as described below, the optical functional layer 12 is formed with light transmitting portions 13, 13,... On the surface of the base material layer 11, and then light absorbing portions in the grooves between the light transmitting portions 13, 13,. It can be produced by forming 14, 14,.

  FIG. 4 is a diagram schematically showing an example of a process for forming the light transmitting portions 13, 13,... In order to form the light transmitting portions 13, 13,..., First, a die roll 42 having grooves having a shape corresponding to the shape of the light transmitting portions 13, 13,. Next, the base material 11 ′ to be the base material layer 11 or including the layer to be the base material layer 11 is fed between the mold roll 42 and the nip roll 41. The arrow shown in FIG. 4 is the direction in which the substrate 11 'is fed. Along with the feeding of the base material 11 ′, droplets of the light transmission part constituting composition 40 described later are continuously supplied from the supply device 45 between the mold roll 42 and the base material 11 ′. When the light transmitting portion constituting composition 40 is supplied from the supply device 45 onto the base material 11 ′, a bank in which the light transmitting portion constituting composition 40 is accumulated is formed between the mold roll 42 and the base material 11 ′. So that In this bank, the light transmitting portion constituting composition 40 spreads in the width direction of the base material 11 ′.

  The light transmitting portion constituting composition 40 supplied between the mold roll 42 and the base material 11 ′ as described above is formed by the pressing force between the mold roll 42 and the nip roll 41. It is filled between the rolls 42. Then, the light transmissive portions 13, 13... Can be formed by irradiating the light transmissive portion constituting composition 40 with ultraviolet rays or the like by the light irradiation device 44 and curing the light transmissive portion constituting composition 40. After the light transmitting portions 13, 13,... Are formed, the sheet on which the light transmitting portions 13, 13,. Torn off.

  Next, in order to form the light absorbing portions 14, 14,..., A light absorbing portion constituting composition described later is supplied onto the light transmitting portions 13, 13,. The excess light absorbing portion constituent composition is scraped off while filling the groove between the light transmitting portions 13, 13,. Thereafter, the light absorbing portions 14, 14,... Can be formed by irradiating the light absorbing portion constituting composition remaining in the grooves between the light transmitting portions 13, 13,.

  As the light transmission part constituting composition, a composition which is cured by light such as ultraviolet rays is preferable. As such a composition, the photocurable resin composition which mix | blended the photocurable prepolymer (P1), the reactive dilution monomer (M1), and photoinitiator (S1) which are mentioned below is preferably used, for example. .

  Examples of the photocurable prepolymer (P1) include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.

  Examples of the reactive dilution monomer (M1) include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.

  Furthermore, examples of the photopolymerization initiator (S1) include a hydroxybenzoyl compound, a benzoylformate compound, a thioxanthone compound, a benzophenone, a phosphate ester compound, and a benzyldimethyl ketal. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. From the viewpoint of preventing the light transmitting portion 13 from coloring, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) are preferable. ) -Phenylphosphine oxide.

  The photocurable prepolymer (P1), the reactive dilution monomer (M1), and the photopolymerization initiator (S1) can be used alone or in combination of two or more. In addition, in the light transmitting part constituting composition, if necessary, silicone additives, rheology control agents, It is also possible to add a defoaming agent, a release agent, an antistatic agent, an ultraviolet absorber and the like.

  In the present embodiment, the light absorbing parts 14, 14,... Are composed of a light absorbing part comprising a light absorbing particle 16, 16,... And a binder 15 in which the light absorbing particles 16, 16,. It is comprised by being filled in the groove | channel between 13, 13, .... Thereby, the light incident on the inner side of the light absorbing portions 14, 14,... Can be absorbed by the light absorbing particles 16, 16,.

  It should be noted that configuring the light absorbing portions 14, 14,... By a predetermined material having a refractive index Nb means that the binder 15 is configured by a material having a refractive index Nb, for example. Although what is used as the said binder 15 is not specifically limited, The composition hardened | cured by light, such as an ultraviolet-ray, is preferable. As such a composition, for example, a photocurable resin composition containing a photocurable prepolymer (P2), a reactive dilution monomer (M2) and a photopolymerization initiator (S2) exemplified below is preferably used. It is done.

  Examples of the photocurable prepolymer (P2) include urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate.

  Moreover, as said reactive dilution monomer (M2), a vinyl monomer, a (meth) acrylic acid ester monomer, and a (meth) acrylamide derivative are mentioned as a monofunctional monomer, for example. Moreover, (meth) acrylate type thing is mentioned as a polyfunctional monomer.

  Further, as the photopolymerization initiator (S2), 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane- Examples include 1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected.

  The photocurable prepolymer (P2), the reactive dilution monomer (M2), and the photopolymerization initiator (S2) can be used alone or in combination of two or more. Specifically, a photopolymerizable component composed of urethane acrylate, epoxy acrylate, tripropylene glycol diacrylate and methoxytriethylene glycol acrylate (specifically, photocurable prepolymer (P2) and reactive dilution monomer (M2)). In consideration of the refractive index, the viscosity, the influence on the performance of the optical function layer 12, etc., they can be arbitrarily mixed and used. Moreover, you may add a silicone, an antifoamer, a leveling agent, a solvent, etc. to an optical absorption part structure composition as an additive as needed.

  The light absorbing particles 16 are preferably light-absorbing colored particles such as carbon black, but are not limited thereto, and are colored particles that selectively absorb a specific wavelength in accordance with the characteristics of 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. The average particle diameter of the colored particles is preferably 1.0 μm or more and 20 μm or less. By using colored particles having an average particle diameter of 1.0 μm or more, in the process of forming the light absorbing portion, the colored particles are difficult to pass through the gap between the doctor blade and the upper portion of the light transmitting portion 13, and the light transmitting portion It is possible to prevent the colored particles from remaining on the top of 13.

  In addition, a light absorption part is not limited to the form using light absorption particles as mentioned above, You may comprise by coloring the whole light absorption part with a pigment.

  As described above, according to the optical function layer 12, the light absorbing unit 14 can absorb more external light OL than the image light VL, and thus the contrast of the image displayed on the screen surface can be increased. . From the viewpoint of absorbing more external light than image light by the light absorption unit, the optical functional layer may have the following form, for example. FIG. 5 is a cross-sectional view schematically showing an optical functional layer 12 ′ according to another embodiment, and corresponds to FIG. 2.

  The optical functional layer 12 ′ is a layer in which light transmitting portions 13 ′ and light absorbing portions 14 ′ are alternately formed. The lower interface 14a 'of the light absorbing portion 14' is formed so as to have an angle close to the incident direction of the video light VL, like the interface 14 described above. On the other hand, the upper interface 14b 'of the light absorbing portion 14' is formed substantially parallel to the interface 14a '. By adopting such a configuration, the amount of image light absorbed by the light absorbing portion 14 ′ can be reduced as compared with the optical function layer 12. In other words, the region where the image light VL is absorbed by the light absorbing portion 14 ′ in the optical function layer 12 ′ (the region indicated by the arrow x 3) is the region where the image light VL is absorbed by the light absorbing portion 14 in the optical function layer 12. (Area indicated by arrow x1 in FIG. 2). In addition, the amount of external light OL incident obliquely from above can be increased by the light absorbing portion 14 '. That is, in the optical function layer 12 ′, the region where the external light OL is absorbed by the light absorbing portion 14 ′ (region indicated by the arrow y 3), the region in the optical functional layer 12 where the external light OL is absorbed by the light absorbing portion 14. (Regions indicated by arrows y1 and y2 in FIG. 2). Therefore, if the optical functional layer 12 'is used, an image with high contrast can be provided. However, the above-described optical functional layer 12 is preferable from the viewpoint of productivity.

  The optical functional layer 12 ′ can be produced, for example, as described below. FIG. 6 is a diagram for explaining a method for producing the optical functional layer 12 ′. In order to produce the optical functional layer 12 ′, for example, as shown in FIG. 6, a laminated body in which light transmitting layers 31 and light absorbing layers 32 are alternately laminated is produced, and the laminated body Can be fabricated by cutting obliquely with respect to the stacking direction as indicated by broken lines in FIG. In this case, in the sheet produced by cutting, the portion of the layer 31 that transmits light becomes the light transmission portion 13 ′, and the portion of the layer 32 that absorbs light becomes the light absorption portion 14 ′.

  In the description of the optical functional layer so far, the case where the image light is transmitted obliquely from below the reflective screen has been described, but the image source may be disposed obliquely above the reflective screen. In this case, by reversing the upper and lower sides of the optical function layer described so far, the contrast of the image displayed on the screen surface can be increased as in the optical function layer described so far. In this case, external light that is reflected from the floor surface or the like and is incident from obliquely below the reflecting screen can be efficiently absorbed by the light absorbing portion.

(Fresnel lens layer 23)
Next, the Fresnel lens layer 23 will be described. As the Fresnel lens layer 23, a layer having a known Fresnel lens can be used without any particular limitation.

  FIG. 7 is an enlarged view of a part of the Fresnel lens layer 23 and shows an example of the optical path of the image light incident on the Fresnel lens layer 23. The Fresnel lens layer 23 includes a plurality of unit lenses 23a. The unit lens 23a has a lens surface including a slope 23b and a rising surface 23c for forming the slope 23b, and is formed to be convex on the side opposite to the observer side. . A light reflecting layer 24 to be described later is formed on the lens surface of the unit lens 23a, and the inclined surface 23b functions as a reflecting surface that reflects light reaching the inclined surface 23b.

  Here, the angle between the inclined surface 23b and the surface perpendicular to the screen surface is α. The α has a deflection function capable of reflecting the image light reaching the Fresnel lens layer 23 from the image source 2 and finally emitting it toward the observer, as shown below as an example of the optical path. It is configured. Therefore, the size of the angle α can be appropriately changed according to the position of the image source 2 that projects the image light. Moreover, it is not necessary to make α the same size in all of the plurality of lens portions 23a, and some of them may be changed or gradually changed along the arrangement direction. These shapes can be appropriately selected in consideration of the angle of light incident on the Fresnel lens layer 23 from the image source 2.

  An example of the optical path of the image light incident on the Fresnel lens layer 23 will be described with reference to FIG. However, the optical path example shown in the figure conceptually represents the path of light, and does not accurately represent the degree of refraction or the angle of reflection.

  As shown in FIG. 7, the image light L1 that has reached the inclined surface 23b from obliquely below is reflected by the light reflecting layer 24 and provided to the observer side. At this time, since the inclined surface 23b has an appropriate inclination angle (α) as described above, the optical path of the image light L1 is controlled so as to be easily seen by the observer.

  The configuration of the unit lens 23a provided in the Fresnel lens layer 23 will be exemplified below. FIG. 8 is a plan view schematically showing the Fresnel lens layer 23.

  Unit lenses 23a, 23a,... Provided in the Fresnel lens layer 23 shown in FIG. 8 are arranged so as to extend on arcs of concentric circles. Further, the configuration of the unit lenses 23a, 23a,... In the horizontal direction is line symmetric with respect to an axis Aa parallel to the vertical direction passing through the center position in the horizontal direction. The configuration of the unit lenses 23a, 23a,... Can be designed based on the arrangement of the image source and the like with respect to the reflective screen 10. For example, when the reflective projection system including the reflective screen 10 is observed from the front, the center O of the concentric circle related to the arrangement of the unit lenses 23a, 23a,... Is overlapped with the arrangement position of the video source 2. design. Thus, by decentering the center O from the center of the Fresnel lens layer 23 in the vertical direction, even when the image light VL is projected obliquely from below the reflective screen 10, the image source 2 is directed toward the reflective screen 10. The spreading light beam can be reflected to be a parallel light beam in the front direction of the reflective screen 10. By adopting a configuration in which the image light VL is irradiated obliquely from below the reflective screen 10, the distance between the reflective screen 10 and the image source 2 can be reduced.

  The material constituting the Fresnel lens layer 23 is not particularly limited, and various materials can be used. However, it is widely used as a material for screens and has excellent mechanical properties, optical properties, stability, workability, etc. and is available at low cost, such as acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc. A transparent resin mainly composed of one or more, or an epoxy acrylate or urethane acrylate-based reactive resin (such as an ionizing radiation curable resin) can be suitably used.

  In addition, although the circular Fresnel lens was illustrated and demonstrated as a Fresnel lens layer, the Fresnel lens layer may be comprised by the 2 or more linear Fresnel lens layer combined so that the arrangement | sequence direction of the unit lens might cross | intersect.

(Light reflecting layer 24)
Next, the light reflection layer 24 will be described. The light reflecting layer 24 is a layer that is formed on the lens surface of the Fresnel lens layer 23 and reflects image light. The light reflecting layer 24 is not particularly limited as long as it can reflect image light, and can be formed by a known means. For example, a boundary surface made of a metal such as aluminum can be formed by vapor deposition, and the boundary surface can be used as the light reflecting layer 24. Alternatively, the light reflecting layer 24 can be formed by spraying a reflective paint by spray coating and drying. As the reflective paint, a mirror paint containing an aluminum piece having a smooth surface and a metallic paint containing a flaky aluminum fine powder (both one liquid and two liquid containing a curing agent may be used). And so on. Further, the light reflection layer 24 can be formed by applying mirror ink or metallic ink by screen printing or other printing methods, and then heat-curing or UV-curing.
The light reflecting layer 24 is not limited to a layer that reflects 100% of the image light. For example, the reflectance can be adjusted as appropriate by mixing white ink (a pigment containing, for example, titanium oxide) and aluminum or black ink.

(Light diffusion layer 22)
Next, the light diffusion layer 22 will be described. The light diffusion layer 22 is a layer that isotropically diffuses the image light reflected by the light reflection layer 24 and emits it to the viewer side. Specifically, the light diffusion layer 22 has a base portion made of a transparent resin and a light diffusing agent dispersed in the base portion. The light diffusing layer 22 diffuses light isotropically, for example, due to the difference in refractive index between the base portion and the light diffusing agent or due to the reflectivity of the light diffusing agent itself. To express functions. However, in the present invention, the light diffusion layer 22 is not limited to a layer that diffuses light isotropically, and may be a layer that anisotropically diffuses light depending on the application of the reflective screen. For example, light can be diffused anisotropically by adjusting the distribution of the light diffusing agent and the shape of the light diffusing agent in the base portion. Image light is diffused by such light diffusing ability of the light diffusing layer 22, and an observer can observe the image within a viewing angle range corresponding to the light diffusing ability of the light diffusing layer 22.

  Examples of the transparent resin constituting the base portion of the light diffusion layer 22 include polyethylene terephthalate (PET), polycarbonate (PC), methyl methacrylate / butadiene / styrene (MBS), acrylic, and triacetyl cellulose (TAC). Resins can be mentioned. MBS is preferable from the viewpoints of availability, ease of handling, formability, and price.

  On the other hand, as an example of the light diffusing agent, particles made of a transparent substance such as silica (silicon dioxide), alumina (aluminum oxide), acrylic resin, polycarbonate resin, or silicone resin having an average particle diameter of about 1 μm to 100 μm are used. Can do. Alternatively, the diffusion component may be a bubble. According to these, light can be scattered by utilizing interface reflection due to a difference in refractive index between the base material and the light diffusing agent.

  The thickness of the light diffusion layer 22 is preferably from 0.1 mm to 2 mm, and more preferably from 0.2 mm to 1.5 mm. If the thickness of the light diffusion layer 22 is less than 0.1 mm, the light diffusion capability of the light diffusion layer 22 may be insufficient. On the other hand, if the thickness of the light diffusion layer 22 exceeds 2 mm, the resolution of the image displayed on the viewer side of the reflective screen 10 is degraded, and the image may be blurred.

(Hard coat layer 21)
Next, the hard coat layer 21 will be described. The hard coat layer 21 is disposed on the outermost surface of the reflective screen 10 and constitutes an image display surface of the reflective screen 10. Therefore, the hard coat layer 21 is given resistance to scratches caused by contact with the outside. As such a hard-coat layer 21, a well-known thing can be used. The hard coat layer 21 can be formed, for example, by curing an ionizing radiation curable resin. Specific examples of the ionizing radiation curable resin include acrylic urethane ionizing radiation curable resins.

(Other layers)
The layers described so far are fixed to each other by fusing or via an adhesive layer. The material of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer is not particularly limited as long as it transmits light and has appropriate adhesiveness. Examples thereof include an acrylic pressure-sensitive adhesive. The adhesive force is, for example, about several N / 25 mm to 20 N / 25 mm.

  In the above description, the hard coat layer, the optical functional layer, the base material layer, the light diffusion layer, the Fresnel lens layer, and the light reflection layer are exemplified. However, the reflection type screen of the present invention is at least optical. A functional layer, a Fresnel lens layer, and a light reflecting layer may be provided, and all the above layers are not essential. Further, other layers may be provided.

As said other layer, the layer with which the conventional reflection type screen was equipped can be used suitably, For example, a light attenuation layer can be mentioned. The light reducing layer is a layer having a function of improving contrast by absorbing a part of outside light. Such a light-reducing layer is configured by mixing a pigment or a dye in the light transmission portion of the light diffusion layer, the pressure-sensitive adhesive layer, or the optical functional layer described above and having these layers also have a function as a light-reducing layer. Alternatively, a layer having only a function as a light reducing layer may be separately formed.
According to such a light reducing layer, at least a part of the external light incident on the reflective screen can be absorbed, and the contrast of the image light provided to the observer can be improved. From such a viewpoint, it is preferable that the light reducing layer is disposed on the viewer side as much as possible.

DESCRIPTION OF SYMBOLS 1 Reflection type projection system 2 Image source 10 Reflection type screen 11 Base material layer 12 Optical functional layer 13 Light transmission part 14 Light absorption part 15 Binder 16 Light absorption particle 20 Light diffusion layer 21 Hard coat layer

Claims (5)

A reflection type screen that allows observation by reflecting image light projected from an image source,
From the side on which the image light is projected, an optical functional layer, a Fresnel lens layer, and a light reflection layer formed on the lens surface of the Fresnel lens layer,
The optical functional layer includes a light transmission portion arranged in parallel so as to transmit light, and a light absorption portion formed so as to be able to absorb light between the light transmission portions,
A refractive index of the light transmitting portion is equal to or lower than a refractive index of the light absorbing portion;
In a cross-sectional view in the layer thickness direction in a posture in which the parallel direction of the light absorption unit is a vertical direction, one of the upper interface and the lower interface among the interfaces with the light transmission unit of the light absorption unit, A reflection formed based on an incident direction of image light assumed to be incident on the optical functional layer, and the other is formed based on an incident direction of light other than the image light assumed to be incident on the optical functional layer. Mold screen.   2. The reflective screen according to claim 1, wherein, in a posture in which a parallel direction of the light absorbing portions is a vertical direction, an angle of the lower interface with respect to a horizontal plane is increased as the arrangement position of the light absorbing portions is higher. .   3. The reflective screen according to claim 1, wherein, in a posture in which the parallel direction of the light absorption units is a vertical direction, the lower interface is closer to the horizontal as the arrangement position of the light absorption units is lower.   A reflective projection system comprising: the reflective screen according to any one of claims 1 to 3; and an image source that projects image light onto the reflective screen.   The reflective projection system according to claim 4, wherein a horizontal distance from a light exit surface of the image source to a viewer-side surface of the reflective screen is 1 m or less.