WO2019004289A1

WO2019004289A1 - Reflective type screen

Info

Publication number: WO2019004289A1
Application number: PCT/JP2018/024394
Authority: WO
Inventors: 純一 ▲角▼田; 澁谷　崇; 雄一 ▲桑▼原
Original assignee: 旭硝子株式会社
Priority date: 2017-06-30
Filing date: 2018-06-27
Publication date: 2019-01-03
Also published as: CN209417512U; JPWO2019004289A1

Abstract

This reflective type screen has: a transparent member having a corrugated surface on one of the primary surfaces; and a light scattering layer provided on the other primary surface that is on the opposite side of the corrugated surface of the transparent member, wherein the corrugated surface satisfies equation (1) 0.0040 ≤ Ra/RSm ≤ 0.010 and equation (2) Sku ≤ 3.5, where Ra is the arithmetic surface roughness, RSm is the average length of a roughness curve element, and Sku is the Kurtosis.

Description

Reflective screen

The present invention relates to a reflective screen.

In recent years, a reflective screen has been developed which has an uneven surface on the front surface on which writing with the ink and erasing of the writing is performed and an image is projected from the front to the uneven surface (see, for example, Patent Document 1). The projected image can be written with ink.

The reflective screen described in Patent Document 1 has a glass plate and a layer containing a light diffusing paint or pigment. The glass plate has an uneven surface on the surface, and writing of characters and figures on the uneven surface and erasing of the writing are enabled. A layer containing a light diffusing paint or pigment is formed on the back of the glass plate to reflect light incident on the surface of the glass plate.

Japanese Patent Application Laid-Open No. 2003-237295

Conventionally, when the height difference of the uneven surface is too large, the ink is difficult to remove from the inside of the recess, and when the height difference of the uneven surface is too small, hot spots are easily generated, improving the erasability of writing and suppressing the generation of hot spots. It was difficult to achieve both.

Here, the hot spot is a phenomenon in which the central portion of the reflective screen appears bright when the image is projected on the reflective screen. This phenomenon occurs when the front of the reflective screen reflects incident light.

The present invention has been made in view of the above problems, and its main object is to provide a reflective screen in which the erasability of writing with ink is improved and the occurrence of hot spots is suppressed.

According to one aspect of the present invention, in order to solve the above problems,
A transparent member having an uneven surface on one of the main surfaces,
And a light scattering layer provided on the main surface of the transparent member opposite to the uneven surface,
The uneven surface is
0.0040 ≦ Ra / RSm ≦ 0.010 (1)
Sku ≦ 3.5 (2)
Ra: Arithmetic mean roughness RSm: Average length of roughness curvilinear elements Sku: A reflective screen is provided which satisfies the kurtosis.

According to one aspect of the present invention, there is provided a reflective screen in which the erasability of ink writing is improved and the occurrence of hot spots is suppressed.

FIG. 1 is a front view of a reflective screen according to one embodiment. FIG. 1 is a top view of a reflective screen according to one embodiment. FIG. 2 is a cross-sectional view of a reflective screen according to one embodiment. FIG. 7 illustrates diffuse reflection and diffuse transmission on a textured surface of a reflective screen according to one embodiment. It is a figure which shows the relationship between Sku and height distribution. It is a figure which shows the relationship between Sku and uneven | corrugated shape. It is a figure which shows the result of the high-speed write-out test by Experiment 1-12. It is a figure which shows the evaluation result of the hot spot by Experiment 1-12. It is a figure which shows the result of the continuous writing-out test by Experiment 1, 3, 6, 9, 12. It is sectional drawing which shows the transparent member by a modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and the description thereof will be omitted. In the present specification, “to” representing a numerical range means a range including the numerical values before and after that. Further, in the present specification, “plan view” means that it is viewed from the thickness direction of the reflective screen.

<Reflective screen>
FIG. 1 is a front view of a reflective screen according to one embodiment. FIG. 2 is a top view of a reflective screen according to one embodiment. In FIG. 2, P is a projector, U1 is a user facing the front of the central portion of the reflective screen 10, and U2 is a user who observes the reflected light at the same reflection angle as the incident light from the projector P to the reflective screen 10. Show. FIG. 3 is a cross-sectional view of a reflective screen according to one embodiment.

The reflective screen 10 has a front surface 21 and a rear surface that is the opposite surface of the front surface 21, and has an uneven surface 23 on the front surface 21. Writing with ink and erasing of the writing are performed on the uneven surface 23. Also, an image is projected from the front to the uneven surface 23.

For writing with ink, a writing instrument such as a dedicated marker or a printer head is used. For erasing the written data, a eraser, a solvent, etc. are used. On the other hand, a projector P or the like is used to project an image.

The ink contains, for example, a dye, a solvent for dissolving the dye, and a release agent. An alcohol etc. are used as a solvent. An oil etc. are used as a mold release agent. The dye is not soluble in the release agent. The writability of the ink is evaluated by both the high-speed writting test and the continuous writting test.

In the high-speed write-out test, writing is performed on the uneven surface 23 by moving the dedicated marker at high speed while touching the uneven surface 23. In order to move at a high speed, discharge of the release agent from the dedicated marker is suppressed, and writing with insufficient release agent is performed. In the high-speed write-off test, it is evaluated whether writing with insufficient release agent can be sufficiently erased by the eraser. Specific test conditions will be described in the section of Examples.

On the other hand, in the continuous writing out test, the ink is applied in a predetermined range of the concavo-convex surface 23 to repeat writing on the concavo-convex surface 23 and erasing the writing with the eraser 50 times repeatedly. As writing and erasing are repeatedly performed, a film of the release agent is likely to be formed on the uneven surface 23. When a film of the release agent is formed, the pigment is incorporated into the film, and the incorporated pigment becomes difficult to remove by the eraser. In the continuous writing out test, the degree of color remaining due to the formation of the film of the release agent is evaluated. Specific test conditions will be described in the section of Examples.

The reflective screen 10 may be surrounded by a frame (not shown). The frame may be provided with a hanger or a leg, and the leg may be attached with a caster. The reflective screen 10 is used indoors, for example. The use place of the reflective screen 10 is not particularly limited. For example, a reflective screen may be applied to a vehicle or a wall of a building.

The reflective screen 10 includes, for example, a transparent member 20, an adhesive layer 30, a light scattering layer 40, and a light reflecting layer 50 in this order from the front side to the rear side. Hereinafter, each configuration of the reflective screen 10 will be described in this order.

<Transparent member>
The transparent member 20 has a first main surface 21 and a second main surface 22 opposed to each other, and has an uneven surface 23 on the first main surface 21. Writing with ink and erasing of the writing are performed on the uneven surface 23. Also, an image is projected from the front to the uneven surface 23.

The uneven surface 23 occupies the entire surface of the first main surface 21 in FIGS. 1 to 2, but may occupy only a part of the first main surface 21. In the latter case, the remaining portion of the first main surface 21 may be a smooth surface without irregularities. Further, when the uneven surface 23 is partially formed on the first main surface 21, a plurality of uneven surfaces 23 smaller than the first main surface 21 may be arranged at intervals.

The uneven surface 23 may be formed in a rectangular shape in plan view as shown in FIG. The vertical dimension L1 of the uneven surface 23 is, for example, 300 mm or more. Moreover, the horizontal dimension L2 of the uneven surface 23 is 500 mm or more, for example. In addition, the shape in planar view of the uneven surface 23 may be various.

The uneven surface 23 satisfies the following formulas (1) and (2).
0.0040 ≦ Ra / RSm ≦ 0.010 (1)
Sku ≦ 3.5 (2)
Ra: Arithmetic mean roughness (unit: μm)
RSm: Average length of roughness curve element (unit: μm)
Sku: Kurtosis (no unit)
Arithmetic mean roughness Ra and mean length RSm of the roughness curvilinear element are measured in accordance with Japanese Industrial Standard (JIS B0601: 2013). Ra and RSm are measured without setting the cutoff value. Ra and RSm are measured with a laser microscope and a rectangular area of 0.26 mm long and 0.26 mm long at a magnification of 50 × and measured along each of 10 straight lines drawn randomly in the taken image, The average value of the measured values is adopted. Ra represents the height difference of the unevenness, and RSm represents the period of the unevenness (for example, the period of the convex apex).

FIG. 4 is a view showing diffuse reflection and diffuse transmission on the uneven surface of the reflective screen according to one embodiment. In FIG. 4, the arrow A indicates the incidence of light from the projector P (see FIG. 2) to the uneven surface 23, the arrow B indicates the diffuse reflection at the uneven surface 23 of the light incident from the projector P, and the arrow C indicates the unevenness The diffuse reflection of the light transmitted through the surface 23 at the light scattering layer 40 is shown, and the arrow D indicates the diffuse transmission at the uneven surface 23 of the light diffusely reflected by the light scattering layer 40.

When Ra / RSm of the concavo-convex surface 23 is 0.0040 or more, the height difference of the concavities and convexities is sufficiently large as compared with the concavo-convex period, so the incident light from the projector P is easily diffused and reflected on the concavo-convex surface 23 Reflected light from the reflective layer 50 is easily diffused and transmitted. This can suppress the occurrence of hot spots.

The presence or absence of the hot spot is confirmed, for example, at the position of the user U2 shown in FIG.

According to the present embodiment, since Ra / RSm of the concavo-convex surface 23 is 0.0040 or more, diffuse reflection and diffuse transmission easily occur on the concavo-convex surface 23 as described above. As a result, the occurrence of hot spots can be suppressed.

If Ra / RSm of the concavo-convex surface 23 is 0.010 or less, the height difference of the concavities and convexities is not too large compared to the concavo-convex cycle, so the ink written on the concavo-convex surface 23 is easily removed. The insufficient writing of the release agent can be sufficiently erased.

Ra of the uneven surface 23 is preferably 0.10 μm or more. Interference of light can be suppressed as Ra of the uneven surface 23 is 0.10 μm or more, and glare can be suppressed. Glare is a phenomenon in which a fine spotted pattern due to light and dark of light is seen. Speckled patterns are caused by light interference. Ra of the uneven surface 23 is preferably 2.0 μm or less.

Kurtiss Sku is measured in accordance with the international standard (ISO 25178). Sku measures without setting a cutoff value. In Sku, a rectangular area of 0.26 mm long and 0.26 mm long is photographed by a laser microscope and measured at a magnification of 50 and a mean value of the measured values is adopted.

Sku is represented by the following formula (3).

In the above equation (3), Sq represents the root mean square height of the surface, A represents the area, and Z (x, y) represents the height at the surface coordinates (x, y). Sku means kurtosis which is a measure of the sharpness of the surface and represents the sharpness (sharpness) of the height distribution.

FIG. 5 is a diagram showing the relationship between Sku and height distribution. FIG. 5A is a view showing an example of the height distribution when Sku is smaller than 3.0. FIG. 5B is a view showing an example of the height distribution when Sku is 3.0. FIG. 5C is a view showing an example of the height distribution when Sku is larger than 3.0.

As shown in FIG. 5A, when Sku is smaller than 3.0, the height distribution is a distribution more discrete from the average value than the Gaussian distribution, and has a flatter shape than the Gaussian distribution. When Sku is 3.0 as shown in FIG. 5 (b), the height distribution is Gaussian. As shown in FIG. 5C, when Sku is larger than 3.0, the height distribution is a distribution more concentrated on the average value than the Gaussian distribution, and has a shape sharper than the Gaussian distribution.

FIG. 6 is a diagram showing the relationship between Sku and the concavo-convex shape. FIG. 6A shows an example of the concavo-convex shape in the case where Sku is smaller than 3.0. FIG. 6B is a view showing an example of the concavo-convex shape in the case where Sku is larger than 3.0.

When Sku is smaller than 3.0 as shown in FIG. 6A, the convex apex and concave apex are relatively flat as compared with the case where Sku is larger than 3 as shown in FIG. 6B. .

When the Sku of the uneven surface 23 is 3.5 or less, since the peaks are flat and there are sufficiently many bumps and depressions, the ink is easily removed, and the color residue due to the formation of the film of the release agent is reduced in the continuous writing out test. it can. Sku of the uneven surface 23 is preferably 2.0 or more.

While the first main surface 21 of the transparent member 20 has the uneven surface 23, it is preferable that the second main surface 22 (see FIG. 3) of the transparent member 20 has almost no unevenness. The arithmetic mean roughness Ra of the second main surface 22 of the transparent member 20 is, for example, 5 μm or less, preferably 1 μm or less, more preferably 0.1 μm or less.

For example, as shown in FIG. 3, the transparent member 20 may have a transparent substrate 24 and a covering layer 25 provided on the opposite side of the light scattering layer 40 with respect to the transparent substrate 24. The covering layer 25 forms the uneven surface 23. The covering layer 25 may be omitted, and the transparent substrate 24 may form the uneven surface 23.

The transparent substrate 24 is formed of, for example, one selected from glass, polycarbonate resin, acrylic resin, and polyester resin, and is preferably formed of glass from the viewpoint of rigidity and design. Hereinafter, the transparent substrate 24 formed of glass is also referred to as a glass substrate 24.

The glass substrate 24 is formed of, for example, soda lime glass, aluminosilicate glass, alkali-free glass, borosilicate glass, or the like. The glass substrate 24 may be either untempered glass or tempered glass. Untempered glass is obtained by forming molten glass into a plate and annealing. The tempered glass may be either physically tempered glass or chemically tempered glass. Physically tempered glass is a glass surface strengthened by rapidly cooling a uniformly heated glass plate from a temperature near the softening point and generating a compressive stress on the glass surface by the temperature difference between the glass surface and the inside of the glass. . Chemically strengthened glass is one in which the glass surface is strengthened by generating compressive stress on the glass surface by an ion exchange method or the like.

The glass substrate 24 is formed by a float method, a fusion method, or the like. The glass substrate 24 is a flat plate in FIG. 2 but may be a curved plate. As bending for bending a flat plate into a curved plate, gravity forming, press forming or the like is used. In bending, the glass surface may be physically strengthened by quenching the uniformly heated glass plate from a temperature near the softening point and generating a compressive stress on the glass surface by the temperature difference between the glass surface and the inside of the glass . Chemically strengthened glass can be obtained by generating compressive stress on the glass surface by an ion exchange method or the like after bending.

The glass substrate 24 transmits light of an image. The glass substrate 24 is colorless and transparent, but may be colored and transparent. The haze value of the glass substrate 24 is 50% or less. If the haze value of the glass substrate 24 is 50% or less, sufficient transparency can be obtained. The haze value of the glass substrate 24 is usually 1% or less.

The haze value is measured in accordance with the Japanese Industrial Standard (JIS K7136), and of the transmitted light passing through the test plate to be measured in the thickness direction, the transmitted light deviated by 2.5 ° or more from the incident light by forward scattering. It is determined as a percentage of As a light source used for measurement of haze value, D65 light source as described in Japanese Industrial Standard (JIS Z8720: 2012) is used.

The thickness of the glass substrate 24 is not particularly limited, and is, for example, 0.1 mm to 20 mm. The thickness of the glass substrate 24 is preferably 0.3 mm to 8 mm. For example, when the reflective screen 10 is installed on a wall surface, the thickness of the glass substrate 24 tends to be thinner than 0.1 mm, and when the thickness of the glass substrate 24 is larger than 20 mm, the weight of the reflective screen 10 is heavy. It may be necessary to reinforce walls and the like.

The front surface of the glass substrate 24 has an uneven surface. As a processing method of the glass plate which forms a concavo-convex surface in the front of glass substrate 24, a general processing method is used, for example, mechanical methods, such as a blast method, and etching methods, such as wet and dry, are used. In the etching method, an aqueous solution in which hydrogen fluoride and ammonium fluoride are mixed, an ammonium hydrogen fluoride aqueous solution, or the like is used as an etching solution for the glass substrate 24, for example.

The etching method may be any one of a single step or a plurality of steps such as two steps, but a plurality of steps are preferable from the viewpoint of easily obtaining a desired surface shape, and a two step etching is more preferable from the viewpoint of productivity.

For example, after washing away the deposited crystals by washing with water, etc., the glass substrate 24 etched with an aqueous solution (first etching solution) in which hydrogen fluoride and ammonium fluoride are mixed is washed away, and then an aqueous solution containing hydrofluoric acid (first Etching treatment may be performed again with the etching solution 2), and this two-step etching treatment is preferable. The first etching solution may also contain an organic solvent such as alcohol or glycol for adjusting the solubility of the deposited crystals or dissolving the organic substance.

As a two-step etching process, for example, the following method may be used.
8 to 20 mass% of ammonium hydrogen fluoride as a first etching solution, and 0 to 3 of either a fluorinated alkali metal salt such as sodium hydrogen fluoride (NaHF ₂ ) or ammonium hydrogen fluoride (NH ₄ F ₂ ) Prepare an aqueous solution in which mass% and 15 to 40 mass% of propylene glycol are mixed. Next, a textured surface is formed on the surface by disposing the glass in a stationary or agitated first etching solution. The glass can be left in the first etchant for between 3 and 5 minutes, and conditioned by treatment for longer times to produce a rougher surface roughness.

Next, crystals formed on the glass surface by the treatment with the first etching solution are removed by rinsing the surface with water. Next, an aqueous solution containing 5 to 15% by mass of hydrofluoric acid is prepared as a second etching solution. The second etching solution may further contain 2 to 20% by mass of a mineral acid. Examples of mineral acids include sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid. By arranging the glass in the prepared second etching solution, the surface roughness of the uneven surface formed by the first etching solution is reduced, and the gloss of the uneven surface formed by the first etching solution is increased.

By optimizing the etching conditions (hydrofluoric acid concentration and processing time) using the first and second etching solutions, a desired uneven surface can be obtained.

The transparent substrate 24 has a single-layer structure in the present embodiment, but may have a multilayer structure, for example, laminated glass. A laminated glass has a 1st glass plate, a 2nd glass plate, and the intermediate film which joins a 1st glass plate and a 2nd glass plate.

The covering layer 25 covers at least a part of the front surface of the transparent substrate 24 and covers at least the uneven surface of the front surface of the transparent substrate 24. The cover layer 25 has an uneven surface on its front surface that follows the uneven surface of the transparent substrate 24.

The covering layer 25 is formed of, for example, at least one selected from a silicone resin, a fluorine resin, and a urethane resin. The covering layer 25 preferably has a lower affinity to the ink than the glass substrate 24. It becomes easy to erase the writing by the ink.

The cover layer 25 preferably contains a silicone-based cured product from the viewpoint of the affinity to ink and durability. The silicone-based cured product is obtained, for example, by condensation curing at least one of a curable silicone resin and a curable silicone oligomer.

Generally, the difference between silicone resins and silicone oligomers is molecular weight, and silicone resins of relatively low molecular weight are referred to as silicone oligomers. The silicone oligomer generally refers to one having a molecular weight of about 1,000 to a dimer or trimer. Silicone resins and silicone oligomers are composed of silicon-containing bonding units called M units, D units, T units, and Q units.

A curable silicone resin and a curable silicone oligomer are resins having a branched structure mainly composed of T units or Q units, and a resin composed only of T units, a resin composed only of Q units , T units and Q units. The resins may also contain small amounts of M units and D units.

In the curable silicone resin and the curable silicone oligomer, the T unit has one silicon atom and one hydrogen atom or monovalent organic group bonded to the silicon atom and another silicon atom. And a unit having three bonded oxygen atoms (or other functional groups capable of bonding to other silicon atoms).

Monomers forming the silicon-containing bond units _is represented by _{(R'-) a Si (-Z)} 4-a. However, a is an integer of 0 to 3, R 'is a hydrogen atom or a monovalent organic group, and Z is a hydroxyl group, a chlorine atom or a monovalent functional group capable of binding to another silicon atom. When Z is a hydrolyzable group, examples of the hydrolyzable group include an alkoxy group, an acyloxy group, and an isocyanate group.

From the viewpoint of hardness and durability, one having a T unit as a main constituent unit as a silicon-containing bonding unit is preferably used. Here, one having T units as the main constitutional units means organopolysiloxanes in which the ratio of the number of T units to the total number of M units, D units, T units and Q units is 50% to 100%. More preferably, an organopolysiloxane having a ratio of the number of T units of 70% to 100% is used. Moreover, as another unit contained in a small amount other than T unit, D unit and Q unit are preferable.

As the curable silicone resin and the curable silicone oligomer, commercially available compounds can be used. For example, as curable silicone resins, KR 220 L, KR 220 LP, KR 242 A, KR 251, KR 211, KR 255, KR 300, KR 300, KR 311, KR 262 1-1 manufactured by Shin-Etsu Chemical Co., Ltd. SR2402, AY 42-163, Z6018 manufactured by Toray Dow Corning, etc. can be used. . As a curable silicone oligomer, Shin-Etsu Chemical KC89S, KR515, KR500, X40-9225, X40-9246, X40-9250, KR401N, X40-9227, KR510, KR9218, KR213, KR400, X40-2327, KR401, etc. Can be used. One of these may be used alone, or a plurality of types may be used in combination.

The covering layer 25 may contain a fluorine-based compound in addition to the silicone-based cured product in order to improve the erasability of the writing by the ink. The fluorine-based _compound, a compound containing a C _{n F 2n + 1} group or _C n _{F 2n} O groups are preferred. Here, n is a natural number of 1 or more.

The coating layer 25 is formed by applying a coating solution to the glass substrate 24 and curing the applied coating solution. As the coating method, known methods can be used. For example, methods such as spray coating, slit coating, die coating, spin coating, dip coating, curtain coating and the like can be used. The coating liquid contains at least one of a curable silicone resin and a curable silicone oligomer, and a solvent. The coating liquid may further contain at least one of a curing catalyst, a fluorine-based compound, a leveling agent, and a pigment, as necessary. It is preferable to carry out heating and / or active energy ray irradiation to accelerate curing.

When the coating method is used as a method of forming the covering layer 25, the unevenness shape of the uneven surface 23 can be controlled by controlling the application amount of the coating solution and the solid content concentration (nonvolatile content concentration). When the concavo-convex shape of the concavo-convex surface of the glass substrate 24 is the same, the difference in height between the concavo-convex surface 23 of the covering layer 25 decreases as the application amount of the coating liquid increases. Moreover, when the concavo-convex shape of the concavo-convex surface of the glass substrate 24 is the same, the height difference of the concavo-convex surface 23 becomes lower as the solid content concentration of the coating liquid is higher. The coating solution is thinly stretched with a sponge or the like, and then used after wiping off the excess. The amount of coating solution applied can be adjusted by the amount of wiping.

0.01 micrometer or more and 20 micrometers are preferable, and, as for the layer thickness of the coating layer 25, 0.05 micrometer or more and 10 micrometers or less are more preferable. If the layer thickness of the covering layer 25 is less than 0.01 μm, the durability is insufficient. When the layer thickness of the covering layer 25 is more than 20 μm, the height difference of the uneven surface 23 becomes small, and the generation of the hot spot can not be sufficiently suppressed. The covering layer 25 is preferably formed to have an average layer thickness of 0.1 μm.

The transparent member 20 may further have a base layer 26 between the transparent substrate 24 and the covering layer 25 for improving the adhesion between the transparent substrate 24 and the covering layer 25 as shown in FIG.

Although the transparent member 20 has the covering layer 25 on the side opposite to the light scattering layer 40 with reference to the transparent substrate 24 in the present embodiment, the covering member 25 may not be provided. Writing with the ink or erasing of the writing, projection of an image, or the like may be performed on the uneven surface of the transparent substrate 24.

The front surface of the transparent substrate 24 is an uneven surface in the present embodiment, but may be a flat surface. In the latter case, as shown in FIG. 10, the transparent member 20 further includes an uneven layer 27 formed on the flat surface of the transparent substrate 24.

As a method of forming the concavo-convex layer 27, for example, a embossing method, an etching method, an imprint method, a coating method, etc. may be used alone or in any combination.

When the embossing method is used as a method of forming the concavo-convex layer 27, the concavo-convex layer 27 is formed by pressing the mold against the resin layer softened by heating and transferring the concavities and convexities of the mold to the resin layer.

When the etching method is used as a method of forming the uneven layer 27, the uneven surface is formed on the front surface of the resin layer by immersing the resin layer in the etching solution.

When the imprint method is used as a method of forming the concavo-convex layer 27, the concavo-convex layer 27 is formed by sandwiching the transfer material between the transparent substrate 24 and the mold, transferring the concavo-convex pattern of the mold to the transfer material, and solidifying the transfer material. Form Solidification includes light curing and heat curing.

When the coating method is used as a method of forming the concavo-convex layer 27, the concavo-convex layer 27 is formed by applying a coating liquid containing particles and a binder to the transparent substrate 24 and solidifying the applied coating liquid. As a coating method, a spray method is mentioned, for example.

When a spray method is used as a method for forming the uneven layer 27, droplets are applied to the transparent substrate 24 by spraying a coating liquid containing particles and a binder from a thin nozzle under pressure. The particles can be appropriately selected from inorganic particles, organic particles and the like. The binder can be appropriately selected from organic materials and inorganic materials.

Although writing with the ink or erasing of the writing may be performed on the concavo-convex layer 27 or image projection may be performed, writing on the covering layer 25 covering the concavo-convex layer 27 as shown in FIG. , And may be projected video. Further, as shown in FIG. 10, an underlayer 26 may be provided between the uneven layer 27 and the covering layer 25.

When the coating method is used as a method of forming the covering layer 25, the unevenness shape of the uneven surface 23 can be controlled by controlling the application amount of the coating solution and the solid content concentration (nonvolatile content concentration). When the concavo-convex shape of the concavo-convex layer 27 is the same, the difference in height between the concavo-convex surface 23 of the covering layer 25 decreases as the application amount of the coating liquid increases. Moreover, when the concavo-convex shape of the concavo-convex layer 27 is the same, the height difference of the concavo-convex surface 23 of the covering layer 25 becomes lower as the solid content concentration of the coating liquid is higher. The coating solution is thinly stretched with a sponge or the like, and then used after wiping off the excess. The amount of coating solution applied can be adjusted by the amount of wiping.

In the case where the transparent substrate 24 has an uneven surface and the base layer 26 and the covering layer 25 are not further formed on the uneven surface, the uneven surface of the transparent substrate 24 is the uneven surface 23 of the transparent member 20. When the transparent substrate 24 has an uneven surface, and the underlayer 26 and the covering layer 25 are further formed on the uneven surface, the uneven surface of the covering layer 25 is the uneven surface 23 of the transparent member 20.

On the other hand, in the case where the transparent substrate 24 has a flat surface, the uneven layer 27 is formed on the flat surface, and the underlayer 26 or the covering layer 25 is not further formed on the uneven layer 27, the uneven surface of the uneven layer 27 is It is the uneven surface 23 of the transparent member 20. In the case where the transparent substrate 24 has a flat surface, the uneven layer 27 is formed on the flat surface, and the underlayer 26 or the covering layer 25 is further formed on the uneven layer 27, the uneven surface of the covering layer 25 Is the uneven surface 23 of the transparent member 20.

<Adhesive layer>
The adhesive layer 30 is provided between the transparent member 20 and the light scattering layer 40 and bonds the transparent member 20 and the light scattering layer 40. The adhesive layer 30 is used when the light scattering layer 40 is formed into a sheet and then attached to the transparent member 20. As the adhesive layer 30, a general one is used.

In the present embodiment, the light scattering layer 40 is formed into a sheet and then attached to the transparent member 20. However, the light scattering layer 40 may be formed by applying a raw material liquid of the light scattering layer 40 to the transparent member 20. In the latter case, the adhesive layer 30 is unnecessary.

<Light scattering layer>
The light scattering layer 40 scatters the light transmitted through the transparent member 20. Thereby, the light scattering layer 40 has a white color, and the contrast of the image visually recognized by the users U1 and U2 is improved. The light scattering layer 40 is formed of a plurality of materials having different refractive indices. The light scattering layer 40 includes, for example, a matrix portion and light scattering portions scattered in the matrix portion.

The matrix part may contain either an inorganic material or an organic material. The inorganic material may, for example, be silicon dioxide. Examples of the organic material include polyvinyl alcohol resin, polyvinyl butyral resin, epoxy resin, acrylic resin, polyester resin, polycarbonate resin, melamine resin, polyurethane resin, urethane acrylate resin, silicone resin and the like. The organic material may be any of a thermosetting resin, a photocurable resin, and a thermoplastic resin.

The light scattering portion may contain either particles or cavities, or both. The particles may be either inorganic particles or organic particles. Materials of the inorganic particles include silicon dioxide, titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, calcium carbonate, phosphinate, diphosphinate, barium sulfate, talc, mica and the like. Examples of the material of the organic particles include polystyrene resin, acrylic resin, polyurethane resin and the like. The particles may also be porous particles. The pore diameter of the pores of the porous particles is preferably 2 nm to 50 nm. The number average particle size of the particles is 100 nm to 10 μm. The cavity is formed by a stretching operation, a foaming agent, and the like. When the light scattering portion includes a cavity, the light scattering layer 40 is a porous layer.

When the light scattering layer 40 is formed into a film and attached to the transparent member 20, the appropriate blending amount of the particles is in the case where the light scattering portion includes only the particles and both the particles and the cavities. It is different. When only particles are contained, the proportion of particles in the light scattering layer 40 is preferably 20% by volume to 98% by volume, and more preferably 30% by volume to 90% by volume. When both particles and cavities are included, the proportion of particles in the light scattering layer 40 is preferably 0.1% by volume to 50% by volume, and more preferably 0.5% by volume to 30% by volume.

The film used as the light scattering layer 40 may be a stretched film, and it may be a uniaxially stretched film stretched in the extrusion direction (longitudinal direction) of the film, or a biaxially stretched film stretched in the longitudinal direction and the transverse direction. Good.

The stretched film as the light scattering layer 40 is formed of a resin such as a polyester resin, and may include particles in the interior of the resin, and may include particles and cavities formed at the time of stretching starting from the particles. When the particles and the cavity are included, the plurality of particles and the plurality of cavities are dispersed and disposed inside the stretched film.

When the stretched film contains only particles, the particles are formed of, for example, barium sulfate, aluminum oxide, titanium oxide, or calcium carbonate. The particle diameter of the inorganic particles is preferably 1 μm or less.

When the stretched film contains particles and cavities, the particles are formed of talc, mica, calcium carbonate, phosphinate, diphosphinate or the like. The particle size of the particles is preferably 5 μm or less. The adhesion between the particles and the matrix resin is preferably as small as possible to create a void from the vicinity of the particles when the film is stretched. The cavity formed by stretching is a structure elongated in the stretching direction, and is a structure having a high aspect ratio between the thickness direction and the stretching direction. Therefore, even in the case of a thin stretched film, it is possible to include a large number of cavities in the light path, so that efficient reflection is possible even when the proportion of particles is smaller than in the case of particles alone. Including a cavity is likely to increase the contrast of the image.

The light scattering layer 40 may further include a light absorbing portion in addition to the matrix portion and the light scattering portion. The light absorbing portion contains light absorbing particles such as carbon black and titanium black. The ratio of the light absorbing portion to the light scattering layer 40 is, for example, 0.01% by volume to 5% by volume, preferably 0.1% by volume to 3% by volume. The light absorbing unit improves the contrast of the image.

The total light transmittance of the light scattering layer 40 is 15% to 40%. The “total light transmittance” refers to one remaining main surface (for example, the back surface) of the light scattering layer 40 with respect to incident light that is incident at an incident angle of 0 ° on one main surface (for example, the front surface) of the light scattering layer 40 The percentage of the total transmitted light transmitted is meant. The total light transmittance is measured in accordance with the Japanese Industrial Standard (JIS K7136), and is obtained as the transmittance including diffused light among the transmitted light which transmits the test plate to be measured in the thickness direction. As a light source used for measurement of total light transmittance, D65 light source as described in Japanese Industrial Standard (JIS Z8720: 2012) is used.

<Light reflecting layer>
The light reflecting layer 50 reflects the light from the light scattering layer 40 toward the light scattering layer 40. The light reflecting layer 50 is configured of one layer or multiple layers. Specifically as a constituent material of a layer, the following is mentioned. The light reflecting layer 50 includes at least one of (1) a metal layer, (2) a layer containing a resin and light reflecting particles dispersed in the resin, and (3) a dielectric multilayer film, Or more may be included. The combination is not particularly limited. The metal contained in the light reflecting layer 50 is preferably a single metal or alloy containing at least one of silver and aluminum from the viewpoint of reflectance and color.

When the light reflection layer 50 includes a metal layer, the metal layer may be formed by, for example, attaching a metal foil or a metal plate, physical vapor deposition such as sputtering or vacuum evaporation, silver mirror reaction or plating, etc. Can be mentioned.

The light reflecting layer 50 may also include a resin and light reflective particles dispersed in the resin. In this case, the light reflecting layer 50 is formed, for example, by applying a liquid in which a resin composition and light reflecting particles are mixed to the light scattering layer 40 and solidifying the applied liquid. The liquid may contain a solvent. Alternatively, when the resin is a thermoplastic resin, it is formed by extruding a resin material obtained by mixing the resin composition and the light reflective particles into a sheet. For example, metal particles are used as the light reflective particles. The metal is a single metal or alloy containing at least one of silver and aluminum. The shape of the light reflective particles may be spherical or plate-like, but is preferably plate-like from the viewpoint of reflectance.

The light reflecting layer 50 may also include a dielectric multilayer film. The dielectric multilayer film can be formed by a method of laminating a plurality of dielectrics having different refractive indexes. Examples of the high refractive index dielectric include Si ₃ N ₄ , AlN, NbN, SnO ₂ , ZnO, SnZnO, Al ₂ O ₃ , MoO, NbO, TiO ₂ and ZrO ₂ . Examples of dielectrics having a refractive index lower than that of the high refractive index dielectric include SiO ₂ , MgF ₂ , and AlF ₃ .

For the light reflection layer 50, the sum of the regular reflectance, the diffuse reflectance, the external transmittance and the absorptivity is set to 100%. The sum of the regular reflectance and the diffuse reflectance is the total reflectance. As a measurement sample of the regular reflectance and the diffuse reflectance, one in which the light reflection layer 50 is formed on a glass substrate (specifically, a 2 mm thick soda lime glass plate) is used.

The regular reflectance of the light reflecting layer 50 is measured as an absolute reflectance. The specular reflectance of the light reflection layer 50 is such that light having a wavelength of 550 nm is incident at an incident angle of 5 ° from the glass substrate side to the surface on the glass substrate side in the light reflection layer 50 of the measurement sample The detected light is detected by a spectrophotometer to obtain a measurement value. As the spectrophotometer, a commercially available one (for example, manufactured by Hitachi, Ltd., model: U-4100) is used.

On the other hand, the diffuse reflectance of the light reflecting layer 50 is calculated by subtracting the regular reflectance of the light reflecting layer 50 from the total reflectance of the light reflecting layer 50. The total reflectance of the light reflecting layer 50 is measured as an absolute reflectance. The total reflectance of the light reflection layer 50 is determined by placing the measurement sample inside the integrating sphere and setting the incident angle 5 ° from the glass substrate side to the surface of the light reflection layer 50 on the glass substrate side at a wavelength of 550 nm. Light is incident, and light reflected in various directions is collected by an integrating sphere and detected by a spectrophotometer to be a measurement value.

The specular reflectance of the light reflecting layer 50 is preferably 40% or more. If the specular reflectance of the light reflection layer 50 is 40% or more, the image is hardly blurred. The regular reflectance of the light reflecting layer is more preferably 50% or more.

The diffuse reflectance of the light reflecting layer 50 is preferably less than 40%. If the diffuse reflectance of the light reflecting layer 50 is less than 40%, blurring of the image does not occur.

The total of the specular reflectance and the diffuse reflectance of the light reflecting layer 50, that is, the total reflectance of the light reflecting layer 50 is preferably 30 to 100%.

The external transmittance of the light reflecting layer 50 is preferably less than 50%. If the external transmittance of the light reflecting layer 50 is less than 50%, sufficient brightness of the image can be obtained.

The light reflecting layer 50 is preferably a metal layer. In this case, the light reflection layer 50 is formed on the light scattering layer 40 by plating, sputtering, vapor deposition, or the like.

The light reflecting layer 50 is in close contact with the light scattering layer 40 in FIG. 3, but may not be in close contact with the light scattering layer 40, and a gap may be formed between the light reflecting layer 50 and the light scattering layer 40. The light reflecting layer 50 may be formed separately from the light scattering layer 40.

It is preferable that the front surface of the light reflecting layer 50 has almost no unevenness. The arithmetic mean roughness Ra of the front surface of the light reflecting layer 50 is, for example, 5 μm or less, preferably 1 μm or less.

The method of manufacturing the reflective screen has a step of manufacturing a laminate including the glass substrate 24, the light scattering layer 40 and the light reflecting layer 50. In addition, instead of the glass substrate 24, the above-mentioned resin substrate may be used as a transparent substrate.

<Application of reflective screen>
Reflective screens are suitable for applications where projection and scraping occur.

For example, there are display applications such as buildings, and more specifically, the following applications may be mentioned.
-Interior of living space, CM, display of educational images-Display of information and advertisements at car dealers-Supermarket, use as a glass door for retail and public buildings-Advertising display, information notification, applications such as events- Use as a glass wall that can change the pattern of wallpaper. Partitions of bathrooms in hotels, etc. Partitions of bathrooms, airports, stations, hospitals, schools, letters, signs, images, display of videos, temples, shrines, shrines, churches, etc. Display of regional and tourist information in the space, space presentation in commercial facilities, display of characters, signs, images and videos in the stadium, information in the kitchen and projection of images for individuals and use as whiteboards, writing and display are possible Used in schools and meeting rooms as Also used with the user interface.

Examples of applications in table tops, casings and the like include the following applications.
-Restaurant table tops, desks (desktops), kitchen counters, tabletop partitions Also, the following applications can be mentioned as applications in vehicles.
-Partition part of the Shinkansen-Display of TV and DVD images as an in-car partition in a car.

When the reflective screen 10 is installed on a wall or the like in these applications, it can be attached using a general adhesive or sealing material available for construction or the like.

Test Example 1 to Test Example 4 and Test Example 12 are Examples, and Test Examples 5 to 11 are Comparative Examples.

[Test Example 1]
In Test Example 1, a main surface of a glass plate (a soda lime glass made by Asahi Glass, thickness 3 mm) wet-etched was prepared as a transparent member. The wet etching process was performed in two steps using the first etching solution and the second etching solution. An ammonium hydrogen fluoride aqueous solution was used as the first etching solution. The treatment time with the first etching solution was 60 seconds, and then, before the treatment with the second etching solution, crystals formed on the glass surface by the treatment with the first etching solution were removed by water washing. An aqueous solution containing hydrofluoric acid, sulfuric acid, and hydrochloric acid was used as the second etching solution.

The underlayer and the covering layer were not formed on the uneven surface of the wet-etched glass plate.

In Test Example 1, a white PET film as a light scattering layer was previously formed with an aluminum deposition layer as a light reflection layer and bonded with an adhesive on the surface opposite to the uneven surface of the prepared glass plate. A mold screen was made.

As a white PET film, a biaxially stretched film (thickness 50 μm, total light transmittance: 28.5%) having a plurality of cavities formed with aluminum diethylphosphinate aluminum particles (average particle diameter 2 μm) as a starting point was used. .

The aluminum deposited layer was disposed on the opposite side of the white PET film to the glass plate.

[Test Example 2]
A two-step wet-etched glass plate was obtained in the same manner as in Test Example 1 except that the first etching liquid containing ammonium hydrogen fluoride at a higher concentration than the first etching liquid in Test Example 1 was used. The underlayer and the covering layer were not formed on the uneven surface of the wet-etched glass plate.

A light scattering layer and a light reflecting layer were formed on the obtained glass plate in the same manner as in Test Example 1 to prepare a reflective screen.

[Test Example 3]
A two-step wet-etched glass plate was obtained in the same manner as in Test Example 1 except that the first etching solution containing ammonium hydrogen fluoride at a higher concentration than the first etching solution in Test Example 2 was used. . The underlayer and the covering layer were not formed on the uneven surface of the wet-etched glass plate.

A light scattering layer was attached to the obtained glass plate in the same manner as in Test Example 1 to prepare a reflective screen.

[Test Example 4]
In Test Example 4, an uneven surface was formed on one main surface of the glass plate in the same manner as in Test Example 1 except for the conditions of the wet etching process. In the wet etching process, a first etching solution containing ammonium hydrogen fluoride at a higher concentration than that of Test Example 3 was used. Unlike the test example 1, the coating layer was formed in the uneven surface of the glass plate by which the wet etching process was carried out.

Specifically, a coating solution for the coating layer (KR 400 manufactured by Shin-Etsu Chemical Co., Ltd.) was dropped and spread with a sponge, and an excess coating solution for the coating layer was wiped using Bencot (Asahi Kasei Corporation). Then, the coating layer was formed by heat-processing for 30 minutes at 200 degreeC.

In Test Example 4, as in Test Example 1, a white PET film as a light scattering layer was formed with an aluminum deposition layer as a light reflection layer on the surface opposite to the uneven surface of the prepared glass plate. It stuck with the medicine.

[Test Example 5]
In Test Example 5, blasting and wet etching were used in this order as a method of forming an uneven surface on one of the main surfaces of the glass plate. In the blasting process, the blasting apparatus was a direct pressure type, the media was alumina # 480, the nozzle distance was 60 mm, the jetting pressure was 0.3 MPa, and the processing time per sheet was 6.72 seconds. The wet etching process was performed by treating with a 10 mass% hydrofluoric acid aqueous solution for 60 seconds. The base layer and the coating layer were not formed on the blasted surface. In Test Example 5, a white PET film as a light scattering layer on which an aluminum deposition layer as a light reflecting layer was formed in advance was adhered with an adhesive on the surface of the prepared glass plate opposite to the uneven surface. A mold screen was made.

As a white PET film, a biaxially stretched film (thickness 50 μm, total light transmittance: 28.5%) having a plurality of cavities formed with aluminum diethylphosphinate aluminum particles (average particle diameter 2 μm) as a starting point was used. .
The aluminum deposition layer was disposed on the opposite side of the white PET film to the glass plate.

[Test Example 6]
In Test Example 6, only blasting was used as a method of forming an uneven surface on one of the main surfaces of a glass plate. The blast treatment was performed in the same manner as the blast treatment in Test Example 5.

A light scattering layer and a light reflecting layer were formed on the obtained glass plate in the same manner as in Test Example 5 to prepare a reflective screen.

[Test Examples 7 to 11]
In Test Examples 7 to 11, only blasting was used as a method of forming an uneven surface on one of the main surfaces of a glass plate. The blasting was performed in the same manner as the blasting in Test Example 5 except for the type of media. In Test Example 7, alumina # 600 was used as the medium. In Test Example 8, alumina # 360 was used as the medium. In Test Example 9, alumina # 480 was used as the medium. In Test Example 10, alumina # 600 was used as the medium. In Test Example 11, alumina # 1000 was used as the medium.

In Test Example 7, a light scattering layer and a light reflection layer were formed on the obtained glass plate in the same manner as in Test Example 5 to produce a reflective screen. The underlayer and the covering layer were not formed on the uneven surface of the treated glass plate. On the other hand, in Test Examples 8 to 11, a light scattering layer and a light reflection layer were formed on the obtained glass plate in the same manner as in Test Example 5. And the coating layer was formed in the uneven surface of the processed glass plate. The coating layer was formed by applying the following coating solution to the entire uneven surface of the glass plate by a spin coater, and drying the applied coating solution at 150 ° C. for 30 minutes. As the coating solution, a solution obtained by diluting silicone oligomer-based coating agent KR400 (manufactured by Shin-Etsu Chemical Co., Ltd.) to 50% with toluene was used. The layer thickness of the coating layer was 0.5 μm.

[Test Example 12]
In Test Example 12, the glass plate obtained in Test Example 1 was used. The underlayer and the covering layer were not formed on the wet-etched surface.

In Test Example 12, a white paint (GLS-HF619 manufactured by Teikoku Ink Co., Ltd.) was applied as a light scattering layer on the surface of the prepared glass plate opposite to the uneven surface, and heat curing was performed at 150 ° C. for 30 minutes. The light reflection layer was not formed. No void was formed in the light scattering layer.

<Measurement of surface shape of uneven surface>
The surface shape of the uneven surface was measured by a laser microscope LEXT (OLS-4100) manufactured by Olympus.

Arithmetic mean roughness Ra and mean length RSm of the roughness curvilinear element were each measured according to Japanese Industrial Standard (JIS B0601: 2013). Ra and RSm were measured without setting the cutoff value. For Ra and RSm, a rectangular area of 260 μm by 260 μm is photographed with a laser microscope at a magnification of 50 times, and it is measured along each of 10 straight lines drawn randomly in the photographed image. The average value was adopted.

Kurtiss Sku was measured in accordance with the international standard (ISO 25178). Sku was measured without setting the cutoff value. Sku was measured at a magnification of 50 × in a rectangular area of 260 μm by 260 μm, and the average value of the measured values was adopted.

<Glossiness>
As a glossiness, a ratio (%) of reflected light reflected at a reflection angle of 60 ° to incident light incident at an incidence angle of 60 ° was measured using a Gloss meter (Rhopoint IQ-S, manufactured by Rhopoint Instruments). In the measurement of glossiness, the back side of the reflective screen was covered with a black felt cloth, and the reflection on the back side of the reflective screen was measured in a state of being suppressed. The glossiness is preferably less than 65%.

<Hot spot evaluation>
The hot spot was evaluated visually by projecting an image on a reflective screen from a liquid crystal projector (Qumi, maximum brightness: 800 lumens) which was directly faced to the reflective screen at a distance of about 1 m.

In the following Table 1 and FIG. 8 showing the evaluation results of the hot spot, “o” means that the presence of the hot spot was not recognized when the image was projected on the reflective screen, “x” means It means that the presence of a hotspot has been recognized.

<High-speed write-out test>
In the high-speed write-out test, a red whiteboard marker (Kokuyo product, whiteboard marker PM-B102NR) is used as a dedicated marker, and a eraser is a whiteboard eraser (Kokuyo product, RA-12NB-DM) Was used.

Three lines were drawn on the uneven surface of the reflective screen with a dedicated marker, and the color residue when these lines were erased with a eraser was visually evaluated. The moving speed (line drawing speed) of the dedicated marker pressed against the reflective screen was 20 cm / sec, and the load for pressing the dedicated marker against the reflective screen was 0.98 N.

In the following Table 1 and FIG. 7 showing the evaluation results of the high-speed write-out test, "o" means that no color residue was observed, and "x" means that a color residue was recognized. .

<Continuous write-out test>
In the continuous writing out test, a red whiteboard marker (BoardMarkerEZcapYYS17-R manufactured by Zebra) was used as a dedicated marker, and a whiteboard eraser (RA-12NB-DM manufactured by KOKUYO) was used as a eraser. .

A circle with a diameter of 50 mm was drawn on the irregular surface of the reflective screen with a dedicated marker, the inside of the circle was filled, and erasing of the drawn circle was repeated 50 times to evaluate the degree of color remaining. The moving speed of the dedicated marker pressed against the reflective screen was 1 cm / sec, and the load for pressing the dedicated marker against the reflective screen was 0.98 N.

Degree of color ^remaining, L ^* a * ^{b *} color system color difference in ^{(CIE 1976) ΔE * ab (} ΔE * ab = {(ΔL *) 2 + (Δa *) 2 + (Δb *) 2} 1 / ² ) rated it. ΔL ^* , Δa ^* , Δb ^* represent changes in L ^* , a ^* , b ^* before and after the continuous writing out test. ΔE ^* ab is preferably less than 2.0, more preferably 1.5 or less, and particularly preferably 1.0 or less. When ΔE ^* ab was less than 1.0, no color residue was visible.

<Glare>
The presence or absence of glare was evaluated based on whether or not a fine spot pattern of light and dark was visible at the position of the user U1 shown in FIG. 2 when an image was projected from a projector on a reflective screen as shown in FIG. In Table 1 below showing the evaluation results of glare, "o" means that no glare was observed, and "x" means that a glare was recognized.

<Contrast>
For evaluation of contrast, a stripe pattern in which white (highest luminance part) and black (lowest luminance part) are alternately repeated is projected from a liquid crystal projector (manufactured by Qumi, maximum luminance: 800 lumens), and luminance is saturated in bright white parts I adjusted the ISO sensitivity of the digital camera so as not to shoot an image. Next, the average luminance of the white part of the photograph obtained was divided by the average luminance of the black part to obtain a contrast. For the luminance analysis, for example, image analysis software such as ImageJ was used.

<Evaluation result>
The evaluation results are shown in Table 1 and FIGS. 7-9. Table 1 summarizes the various evaluation results of Test Examples 1 to 12. FIG. 7 is a diagram showing the results of the high-speed write-out test according to Test Examples 1-12. FIG. 8 is a diagram showing the evaluation results of hot spots according to Test Examples 1 to 12. FIG. 9 is a figure which shows the result of the continuous rewriting test by test example 1, 3, 6, 9, 12. FIG.

As is clear from Table 1 and FIG. 7, in Test Examples 1 to 4 and 9 to 12, the Ra / RSm of the uneven surface of the reflective screen was 0.010 or less, unlike Test Examples 5 to 8. No color residue was visible in the fast write-out test. This is because when the Ra / RS m of the uneven surface is 0.010 or less, the height difference of the unevenness is not too large compared to the period of the unevenness, so the ink written on the uneven surface is easily removed. This is because the insufficient writing can be sufficiently erased.

Further, as is clear from Table 1 and FIG. 8, in Test Examples 1 to 9 and 12, unlike in Test Examples 10 to 11, since the Ra / RSm of the uneven surface of the reflective screen was 0.0040 or more, We were able to suppress the occurrence of hotspots. This is because the height difference of the unevenness is sufficiently large compared to the period of the unevenness, so the incident light from the projector is easily diffused and reflected on the uneven surface of the reflective screen, and the reflected light from the light reflecting layer is easily diffused and transmitted It is for.

It can also be understood from Table 1 and FIG. 8 that there is a correlation between the evaluation result of the hot spot and the glossiness. Since the glossiness measures the specular reflectance, there is a correlation between the hot spots generated due to the specular reflection and the glossiness. Hot spots were observed when the glossiness was 50% or more.

Furthermore, as is clear from Table 1 and FIG. 9, in Test Examples 1, 3 and 12, unlike in Test Examples 6 and 9, since the kurtosis Sku of the uneven surface of the reflective screen was 3.5 or less, Before and after the writing-off test, ΔE ^* ab was less than 2.0, and there were few color residues. This is because the height difference of the unevenness is sufficiently large compared to the period of the unevenness, so the incident light from the projector P is easily diffused and reflected on the uneven surface 23, and the reflected light from the light reflecting layer 50 is easily diffused and transmitted. It is. This is because if the kurtosis Sku of the uneven surface is 3.5 or less, the peaks are flat and there are sufficiently many projections and depressions, so the ink can be easily removed and the color residue due to the formation of the film of the release agent can be reduced. It is. The continuous writing out test was performed in Test Examples 1, 3, 6, 9 and 12, and was not performed in Test Examples 2, 4-5, 7-8, 10-11.

<Deformation, improvement>
As mentioned above, although the embodiment etc. of a reflection type screen were explained, the present invention is not limited to the above-mentioned embodiment etc., within the range of the gist of the present invention described in the claim, various modification and improvement are possible It is.

For example, the reflective screen may further comprise a magnetic layer. The magnetic layer may include any of soft magnetic materials such as iron and hard magnetic materials such as permanent magnets. The attractive force of the magnet can be used, and paper can be fixed to the reflective screen, and the reflective screen can be attached to the wall.

The reflective screen may further have a protective layer such as a corrosion prevention layer on the opposite side to the light scattering layer 40 with respect to the light reflective layer 50. The light reflecting layer 50 can be protected.

Also, the reflective screen may have a transparent substrate on both sides of the light scattering layer 40 and the light reflecting layer 50. That is, the light scattering layer 40 or the light reflecting layer 50 may be provided between the first transparent substrate and the second transparent substrate, and the light scattering layer 40 or the light reflecting layer 50 is provided inside the laminated plate. May be When the first transparent substrate and the second transparent substrate are respectively glass plates, laminated glass can be obtained as a laminated plate. Incidentally, both of the first transparent substrate and the second transparent substrate may be a resin plate, or one may be a glass plate and the other may be a resin plate.

In addition, the light reflection layer 50 may be one in which diffuse reflection is dominant rather than regular reflection. As such a light reflection layer 50, a layer in which spherical reflective particles are dispersed, and a layer having a reflective uneven structure may be mentioned. The layer having a reflective uneven structure can be obtained, for example, by applying a metal reflective film along the uneven surface. The reflective uneven structure may be a random uneven structure, a regular uneven structure, a hologram or the like.

This application claims priority based on Japanese Patent Application No. 2017-128646 filed on Jun. 30, 2017, and the entire contents of Japanese Patent Application No. 2017-128646 are incorporated into the present application. Do.

DESCRIPTION OF REFERENCE NUMERALS 10 reflective type screen 20 transparent member 21 first main surface 22 second main surface 23 uneven surface 24 transparent substrate 25 covering layer 26 underlying layer 27 uneven layer 30 adhesive layer 40 light scattering layer 50 light reflecting layer

Claims

A transparent member having an uneven surface on one of the main surfaces,
And a light scattering layer provided on the main surface of the transparent member opposite to the uneven surface,
The uneven surface is
0.0040 ≦ Ra / RSm ≦ 0.010 (1)
Sku ≦ 3.5 (2)
Ra: Arithmetic mean roughness RSm: Average length of roughness curvilinear element Sku: Reflective screen satisfying kurtosis.
The reflective screen according to claim 1, wherein an arithmetic average roughness Ra of the uneven surface of the transparent member is 0.10 μm or more.
The reflective screen according to claim 1 or 2, wherein the total light transmittance of the light scattering layer is 15% to 40%.
The reflective screen according to any one of claims 1 to 3, wherein the light scattering layer contains a plurality of cavities therein.
The reflective screen according to any one of claims 1 to 4, wherein the light scattering layer is a stretched film having a plurality of cavities therein, and the cavities are formed from particles.
The reflective screen according to any one of claims 1 to 5, wherein the transparent member comprises a glass plate.
The reflective screen according to any one of claims 1 to 6, wherein the thickness of the light scattering layer is 10 μm to 150 μm.