JP5183559B2 - Angle-selective light-shielding sheet and awning comprising the sheet - Google Patents

Description

  The present invention relates to an angle-selective light-shielding sheet and a sunshade comprising the sheet, and in particular, it is installed near a window to block only light irradiated at a high angle such as summer sunlight, and to be irradiated at a low angle such as sunlight in winter. The present invention relates to an angle-selective light-shielding sheet and an awning suitable for awning that can be guided indoors without blocking light.

  Conventionally, shades, curtains, blinds, and the like have been used as awnings for blocking the sunlight irradiated into the room from the window and adjusting the amount of light in the room. These can be removed or replaced depending on the season, or the angle of the blades can be changed as necessary to block out the outdoor light when it is strong, and incorporate the outdoor light when it is weak. Is adjusted. When the outdoor light is strong, the outdoor light may be blocked by hitting a curtain or the like, and part of the light may be diffused and transmitted to irradiate the interior with diffused light.

  A curtain that diffuses and transmits external light is characterized in that a light-refractive pattern such as a lenticular, linear prism, or pyramid prism is provided on at least one side of a curtain made of a light-transmitting material. A light distribution control curtain has been proposed (see Patent Document 1). According to this light distribution control curtain, for example, in the winter, sunlight can be guided almost horizontally deep from the window, and in the summer, the light can be directed to the ceiling, or conversely, the light can be directed to the window floor. To achieve this, it is necessary to prepare several types of light distribution control curtains and replace them according to the surrounding conditions. However, it is unavoidable to prepare curtains according to the seasons, and storage is troublesome, and it is extremely complicated to replace the curtains according to changes in the environment such as the seasons.

  On the other hand, as a light-shielding structure that does not need to be replaced depending on the season, for example, a daylighting surface that transmits sunlight is provided in part or all of the eaves protruding from the eaves of the building, and in close proximity to this daylighting surface. There has been proposed a buttock structure of a building characterized in that a louver is attached and the blades of the louver are inclined in a downward direction as they approach the opening of the building (see Patent Document 2). However, such a collar structure requires a large space and includes a problem that it is difficult to attach to an existing window later.

JP-A-6-33671 JP 2003-301578 A

  In view of such circumstances, the present invention solves the above-mentioned problems of the prior art, and in particular, it can be easily installed on an existing window by retrofitting, and there is no need to replace it depending on the season. An object of the present invention is to provide an angle-selective light-shielding sheet useful as an awning to be adjusted and a awning comprising the sheet.

The present invention was made to achieve the above object, and claim 1 of the present invention includes two prism sheets and a low refractive layer interposed between the prism sheets,
The low refractive layer comprises an air layer ;
The prism sheet has a prism surface provided with a prism array on the outer surface and a flat surface on the inner surface, and the unit prisms in the two prism sheets are arranged so as to be substantially parallel to each other,
The content of the angle-selective light-shielding sheet is that the light is shielded by total reflection at the interface between the prism sheet and the low refractive layer.

According to a second aspect of the present invention , the low refractive layer is interposed between the prism sheets by sticking the prism sheets to both sides of the lattice-shaped crosspiece. The content is a selective light-shielding sheet.

  According to a third aspect of the present invention, there is provided an awning comprising the angle-selective light-shielding sheet according to the first or second aspect.

  The angle-selective light-shielding sheet of the present invention is useful as a peep prevention sheet for mobile phones, but is particularly useful as an awning. That is, when direct sunlight is irradiated at a high angle, such as during summer daytime, the sunlight is reflected, and when direct sunlight is irradiated at a low angle, such as during winter, the sunlight is transmitted. The amount of sunlight entering the room can be adjusted by the awning, and it is not necessary to replace it with another awning that has a different amount of light transmission depending on the season. In addition, the space required for installation is small, and it is easy to retrofit to existing windows.

  If an air layer is used as the low refractive layer, the difference in refractive index with the prism sheet can be increased to increase the critical angle, so that light can be reflected more efficiently.

FIG. 1 is a schematic sectional view of an angle selective light shielding sheet according to the present invention. FIG. 2 is an explanatory diagram showing an optical path when sunlight irradiated from a high angle is reflected by the angle selective light shielding sheet according to the present invention. FIG. 3 is an explanatory diagram showing an optical path when sunlight irradiated from a low angle is transmitted by the angle selective light shielding sheet according to the present invention. FIG. 4 is a graph showing the relationship between the altitude of the sun and the time on the day of the summer solstice near Osaka. FIG. 5 is a graph showing the relationship between the altitude of the sun and the time of autumn day in the vicinity of Osaka. FIG. 6 is a graph showing the relationship between the altitude of the sun and the time on the winter solstice day in the vicinity of Osaka.

As shown in FIG. 1, the angle-selective light-shielding sheet 1 according to the present invention includes two prism sheets 2 and a low refractive layer 3 interposed between the prism sheets 2. The prism sheet 2 is formed of an air layer , and the prism sheet 2 has an outer surface as a prism surface 2a provided with the prism array 2 and an inner surface as a flat surface 2b. The unit prisms of the two prism sheets 2 are substantially the same. It arrange | positions so that it may become parallel, and it is comprised so that it may light-shield by the total reflection in the interface between a prism sheet and a low refractive layer.

  The prism sheet 2 used in the angle-selective light-shielding sheet 1 of the present invention is a film-like or plate-like member having one surface as a prism surface 2a and the other surface as a flat surface 2b. The material can be used as long as the material has high transparency and a relatively high refractive index. Specifically, acrylic resin, polycarbonate, polystyrene, polyvinyl chloride, polyolefin such as polypropylene and polymethylpentene, cyclic polyolefin, Transparent materials such as polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, thermoplastic resins such as polyamide resins, polyarylate, and polyimide, and curable resins that are cured by ionizing radiation such as acrylic resins Can be selected according to the required performance.

The prism surface 2a provided on one side of the prism sheet 2 is a surface provided with a prism array in which unit prisms are arranged, but the pitch of the prisms is not particularly limited. It can be arbitrarily selected from 10 μm to several hundred μm.
The apex angle of the prism may be designed according to the required performance. However, in the normal case, when the apex angle is less than 80 °, for example, in the case of the prism sheet 2 made of resin, the resin spreads to the tip of the prism. Therefore, it is preferable to set the angle to 80 ° or more because the performance of the prism sheet 2 is deteriorated or the tip of the prism is easily broken. Moreover, about the upper limit of an apex angle, when using as an awning, for example, in consideration of the solar altitude of the daytime from June to August in Japan, 140 degrees or less is preferable.

  The other surface side of the prism sheet 2 is a flat surface 2b. The flat surface 2b is a flat surface that is sufficiently smooth with respect to the wavelength of the light to be shielded, and totally reflects the irradiated light depending on the incident angle of the light, but the entire surface of the flat surface 2b does not need to be smooth, A protrusion, a protrusion, etc. may be provided in a part.

In the present invention, the low-refractive layer 3 is a layer interposed between the two prism sheets 2, and the material thereof may be a transparent substance having a lower refractive index than the material constituting the prism sheet 2, For example, using two types of transparent resins with different refractive indexes, create a prism sheet 2 with a material with a high refractive index, create a low refractive layer with a material with a lower refractive index, and paste them together to make angle selectivity. The light shielding sheet 1 can also be used. Preferably, an air layer may be adopted as the low refractive layer 3 in order to increase the refractive index with the prism sheet 2 and increase the critical angle.
The method of providing the air layer is not particularly limited. For example, vertical and horizontal grid-like bars 4 such as shoji bars are used, and the prism sheet 2 is attached to both sides of the bars so that the flat surface 2b is inside. A method is mentioned. In the example shown in FIG. 1, the crosspiece 4 is interposed between the two prism sheets 2. As the material of such a crosspiece 4, the same material as that of the prism sheet described above is preferably used. The crosspieces 4 are preferably as small as possible so as not to prevent light transmission.

The angle-selective light-shielding sheet 1 configured as described above is used by being erected in such a manner that the unit prisms of the prism sheet 2 face sideways when used as an awning. In other words, the awning 1 of the present invention is in a state in which the prism array in which the unit prisms extending in the horizontal direction are arranged in the vertical direction is provided on the prism surface when in use.
When the sunshade 1 according to the present invention is irradiated with sunlight from a high angle, as shown in FIG. 2, the light incident from the slope of the prism enters the interface between the prism sheet 2 and the low refractive layer 3. However, if the incident angle α is larger than the critical angle, total reflection occurs at this interface, so that direct sunlight is blocked by the awning 1.
Further, when sunlight is irradiated from a low angle, as shown in FIG. 3A, the light incident from the slope of the prism enters the interface between the prism sheet 2 and the low refractive layer 3, but the incident If the angle β is smaller than the critical angle, total reflection does not occur, and direct sunlight passes through the awning 1. However, the direction of the light that has passed through one prism sheet 2 is tilted downward, so that not only the sunlight cannot be guided to the back of the room, but also when the outside of the window is viewed through the prism sheet 2 Because the scenery looks distorted, the feeling of strangeness becomes stronger. Therefore, in the present invention, the prism sheet 2 is further provided on the indoor side of the low refractive layer 3, and the light is incident from the flat surface 2b side of the second prism sheet 2, thereby returning the direction of sunlight to the original direction, The distortion of the landscape when viewed through one prism sheet 2 is reduced.
Thus, according to the awning 1 of the present invention, the sun is blocked during the daytime in the summer when the solar altitude is high, and the sun is introduced into the room all day in the winter when the solar altitude is not high. It can handle both winter and summer.

In the present invention, the angle (hereinafter referred to as the critical reflection angle) between the light passing through the awning 1 and the light to be blocked is the inclination angle of the upper surface of the prism and the refraction of the prism sheet 2 and the low refractive layer 3. It can be adjusted by adjusting the ratio of the rates.
That is, within the range of 0 to 90 °, the smaller the inclination angle of the upper slope of the prism (the larger the angle formed by the surface parallel to the entire prism sheet 2 and the upper slope of the prism), the more the irradiated sunlight can be blocked. As the range becomes wider and the refractive index of the prism sheet 2 with respect to the low refractive layer 3 is higher, the range in which the irradiated sunlight can be blocked becomes wider.
Even if the critical angle of reflection of the awning 1 is the same, the time for blocking the sunlight can be slightly adjusted by tilting the awning 1. That is, if the sunshade 1 is tilted in the outdoor direction, it is easy to block direct sunlight, and if it is tilted in the indoor direction, it is easy to transmit. Therefore, it is preferable to provide an angle adjusting mechanism (not shown) for tilting the awning 1.

  As described above, the angle-selective light-shielding sheet 1 of the present invention is suitable as an awning, and is attached to the surface of a liquid crystal display device such as a mobile phone to prevent peeping from the side. It can also be used as a protective sheet.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples.

Example 1
A transparent resin of polyethylene naphthalate (PEN) “Teonex (trade name)” (manufactured by Teijin Chemicals Ltd., refractive index: 1.64) is extruded into a sheet from a die by melt extrusion, and the extruded sheet-shaped molten resin is A prism sheet was manufactured by a method of narrowing the pressure between the molding roll and the cooling roll.
The prism array engraved as a female mold on the mold roll is an isosceles triangle with a cross-sectional shape of an apex angle of 80 ° and a base angle of 50 °, and a prism sheet on which unit prisms having a bottom surface width of 50 μm are arranged. It is for creating.
The thickness of the part obtained by removing the prism array from the obtained prism sheet was 260 μm.
Separately, a grid-shaped crosspiece of 1 mm square rod-shaped members made of 100 mm vertically and horizontally is arranged, and the prism sheet prepared as described above is formed on both sides of the crosspiece with the flat surface on the inside. Thus, the angle-selective light-shielding sheet of the present invention was obtained by sticking so that the unit prisms of the two prism sheets were parallel to each other.

Example 2
The angle-selective light-shielding of the present invention is the same as in Example 1 except that a transparent resin “U-polymer (trade name)” (manufactured by Unitika Ltd., refractive index: 1.61) is used as the resin. A sheet was used.

Example 3
The angle selection according to the present invention is the same as in Example 1 except that the transparent resin “Iupilon (trade name)” (Mitsubishi Engineering Plastics Co., Ltd., refractive index: 1.585) of polycarbonate (PC) is used as the resin. A light-shielding sheet was obtained.

Example 4
The angle-selective light shielding of the present invention was carried out in the same manner as in Example 1 except that a transparent resin “Adekaoptomer (trade name)” (manufactured by ADEKA, refractive index: 1.55) was used as the resin. A sheet was used.

Example 5
As the resin, a transparent resin “Estyrene MS (trade name)” (manufactured by Nippon Steel Chemical Co., Ltd., refractive index: 1.51) of MMA-styrene copolymer (MS) was used in the same manner as in Example 1, The angle-selective light-shielding sheet of the present invention was used.

Example 6
The present invention is the same as in Example 1 except that a transparent resin “Acrypet (trade name)” (Mitsubishi Rayon Co., Ltd., refractive index: 1.49) of polymethyl methacrylate (PMMA) is used as the resin. The angle-selective light-shielding sheet.

Examples 7-12
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle with a cross-sectional shape of 90 ° apex and 45 ° with the base.

Examples 13-18
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle with a cross-sectional shape of an apex angle of 100 ° and an angle with the base of 40 °.

Examples 19-24
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle with a cross-sectional shape of 110 ° apex angle and a base angle of 35 °.

Examples 25-30
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle with a cross-sectional shape having an apex angle of 120 ° and an angle with the base of 30 °.

Examples 31-36
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle with a cross-sectional shape of an apex angle of 130 ° and an angle with the base of 25 °.

Examples 37-42
The angle-selective light-shielding sheet of the present invention was obtained in the same manner as in Examples 1 to 6, except that the prism had an isosceles triangle having a cross-sectional shape of an apex angle of 140 ° and a base angle of 20 °.

Measurement of reflection critical angle The angle-selective light-shielding sheets of Examples 1 to 42 were erected on a turntable so that the extending direction of the unit prisms was vertical, and light was irradiated from the front. Thereafter, the presence / absence of light transmitted through the angle-selective light-shielding sheet was measured while rotating the turntable, and the rotation angle of the turntable when there was no transmitted light was defined as the reflection critical angle.
The measurement results are shown in Table 1.

The light blocking time when the above angle selective light blocking sheet is used as a shade is calculated.
First, with reference to astronomical data (URL: http://homepage3.nifty.com/ueyama/sky2/calc/sunalt.html) published on the Internet, the summer solstice near Osaka (June 21, 2009) Of the sun altitude (September 23, 2009) and winter solstice (December 12, 2009) were calculated and graphed, and the reflection critical angles of Example 1 and Example 42 were overlaid on the graph. (FIGS. 4 to 6). The intersection of these lines was the beginning and end of the time when direct sunlight was blocked.

With a minimum of small Example 1 angular selectivity shielding sheet reflection critical angle in all examples as a sunshade, the temperature rise in the chamber is suppressed, saving the cost of cooling can. From 8:20 am to about 3:20 pm on the day of autumn, the time when direct sunlight is blocked slightly decreases (see Figure 5), and during the winter solstice day, direct sunlight is blocked. It is only 2 hours from 11:00 to 1 pm, and the remaining time can be saved by heating the room because direct sunlight is introduced into the room to warm the room (see FIG. 6).

  When the angle-selective light-shielding sheet of Example 42 having the largest reflection critical angle among all Examples is used as a sunshade, the time during which direct sunlight is irradiated into the room is extended. That is, direct sunlight is blocked by the light-shielding sheet on the summer solstice from 9:30 am to 2:30 pm (see FIG. 4), and direct sunlight is blocked on the autumn day. Is only about 1 hour from around 11:20 am to around 0:20 pm (see FIG. 5). On the day of the winter solstice, direct sunlight is introduced into the room throughout the day to warm the room, thus saving heating costs (see FIG. 6).

As shown in Table 1 above, the critical reflection angle can be freely designed at least between 29 ° and 54 °, and can be designed in a wider range by devising the prism sheet material and prism apex angle. The time for introducing direct sunlight into the room can be adjusted by selecting and using an appropriate sunshade in consideration of the difference between the sunshine time and the solar altitude in the region where the sunshade is installed.
Also, even if the sunshine hours and solar altitude are the same, the temperature is different between spring and autumn, so the time when you want to introduce direct sunlight is different, but the angle adjustment mechanism for tilting the awning of the present invention is provided, and the awning is placed outdoors. By tilting in, the time to block direct sunlight can be extended, and by tilting inward, the time can be shortened.

As described above, the angle-selective light-shielding sheet according to the present invention has, for example, a simple structure, blocks only direct sunlight irradiated from a high angle, and transmits direct sunlight irradiated from a low angle. Therefore, it can be easily installed on an existing window by retrofitting, and is useful as a sunshade that automatically adjusts the intensity of light to be taken into the room without having to be replaced according to the season.
In addition, the angle-selective light-shielding sheet of the present invention can be used not only as the above-mentioned sunshade, but also irradiates the front such as a protective sheet for attaching to the surface of a liquid crystal display device such as a mobile phone to prevent peeping. It can be widely used as a light shielding sheet that transmits only light and blocks light irradiated in an oblique direction.

1 Angle-selective light-shielding sheet (awning)
2 Prism sheet 2a Prism surface 2b Flat surface 3 Low refractive layer (air layer)
4 piers

Claims (3)

Two prism sheets and a low refractive layer interposed between the prism sheets,
The low refractive layer comprises an air layer ;
The prism sheet has a prism surface provided with a prism array on the outer surface and a flat surface on the inner surface, and the unit prisms in the two prism sheets are arranged so as to be substantially parallel to each other,
An angle-selective light-shielding sheet configured to shield light by total reflection at an interface between a prism sheet and a low refractive layer. The angle-selective light-shielding sheet according to claim 1 , wherein the low-refractive layer is interposed between the prism sheets by sticking the prism sheets to both sides of the lattice-shaped crosspiece .   An awning comprising the angle-selective light-shielding sheet according to claim 1.

Images