JPH075502A - Angle selective light transmission plate - Google Patents

Abstract

PURPOSE:To provide the transmission plate which maintains good angle selective light transmittance and has high adhesive power and excellent weatherability and reliability by laminating a resin film for adhesion and a silicone resin film which contains many bar-shaped particulate assemblies and is subjected to an oxidation treatment on the side facing this resin film for adhesion between a pair of transparent substrates. CONSTITUTION:This light transmission plate consists of the transparent substrates 1, a transparent conductive film 2, the particulate assemblies 4, the silicone resin film 5 and the resin film 6 for adhesion. The shape of the particulates 3 is preferably a needle-like or planar from the reason that the absorption sectional area of he bar- shaped particulate assemblies 4 obtd. by impression of an external field to the light of the direction perpendicular to the transparent substrates 1 is reduced. The surface of the silicone resin film 5 is subjected to the oxidation treatment and is thereby provided with polar power components, by which the adhesive power to the resin film 6 for adhesion is improved. Gels shrink when the silicone resin film is subjected to the oxidation treatment but the gels near the particulate assemblies 4 hardly shrink and, therefore, rugged shapes are formed on the film surface and the adhesive power is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle-selective light transmitting plate used as an energy-saving glass in applications such as construction and automobiles.

[0002]

2. Description of the Related Art Conventionally, as a technique relating to glass whose transmittance changes depending on the incident angle of light, that is, so-called angle-selective light transmitting glass, for example, chromium [G. Mbise et al., Appl. P
hys. Lett. 54.987 (1989)], or aluminum [J. Appl. Phys. , 69,
3769 (1991)] has been reported.

However, in these angle-selective light-transmitting glasses, for example, the visible light transmittance change width T (0 ° -60 °) at incident angles φ = 0 ° and φ = 60 ° is only 1.
It remained around 5 to 20%.

On the other hand, it is known that a resin plate containing an aggregate of light-absorptive anisotropic fine particles aligned in the electric field direction has a large light transmittance angle selectivity, and a patent application has already been filed. (For example, Japanese Patent Laid-Open No. 4-368830).

[0005]

Silicone resin is the most suitable material for the resin plate from the viewpoint of weather resistance and electrical insulation, but since the silicone is a flexible resin, it is used for automobile or building glass. When it is used as, it is necessary to form a structure with the transparent substrate through the intermediate film. However, since the silicone resin has a small surface free energy, there is a problem that the adhesive force with the intermediate film is small.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an angle that maintains good angle-selective light transmittance, has high adhesive strength, and has improved weather resistance and reliability. It is intended to provide a selective light transmitting plate.

[0007]

That is, the present invention comprises a pair of transparent substrates, an adhesive resin film, and a large number of fine particle aggregates formed in a rod shape in which a plurality of fine particles are arranged in a substantially constant direction. The angle-selective light-transmitting plate is characterized in that a silicone resin film whose surface facing at least the adhesive resin film is oxidized is laminated.

The present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of an essential part showing an angle-selective light transmitting plate of the present invention. In the figure, (1) is a transparent substrate,
(2) shows a transparent conductive film, (3) shows fine particles, (4) shows a fine particle aggregate, (5) shows a silicone resin film, and (6) shows an adhesive resin film.

FIG. 2 is a schematic explanatory view showing the manufacturing process of the present invention. In FIG. 2 (a), fine particles in which a transparent conductive film (2) and fine particles (3) are dispersedly contained on a transparent substrate (1). The dispersion liquid (5 ') is sequentially formed, and the external electrodes (8) facing each other via the gap (7) are arranged.

FIG. 2B shows that by applying an electric field as an external field between the transparent conductive film (2) and the external electrode (8) through the gap (7), the fine particle dispersion liquid (5 '). The fine particles (3) in () are aligned in a certain direction to form a rod-shaped fine particle aggregate (4). In addition, in the present invention, the rod shape is a shape as a fine particle aggregate formed by arranging a plurality of fine particles in a certain direction.
In this case, each fine particle may form a chain or a bundle.

FIG. 1 (c) shows that the fine particle dispersion liquid (5 ') in which the fine particle aggregates (4) are formed is irradiated with UV light.
Alternatively, it is shown that the fine particle dispersion liquid (5 ′) is cured by heating to form a gel or solid film-shaped silicone resin film (5). Furthermore, changes in the surface shape of the silicone resin film (5) due to curing are also shown.

FIG. 1D shows the structure of the angle-selective light-transmitting plate having a structure in which the transparent substrate (1) and the silicone resin film (5) are combined via the adhesive resin film (6). .

As the transparent substrate (1), in addition to a glass substrate such as soda lime glass, a light transmissive member, for example, a polymer such as polycarbonate or polyethylene terephthalate can be used.

The transparent conductive film (2) is not an essential constituent element in the present invention, but when it is arranged on the transparent substrate (1), a conventionally known one can be used and is not particularly limited. . Specific examples thereof include ITO film and Sn.
An example is an O ₂ film, and a resistance value of about 20Ω / □ is sufficient. Further, the film thickness is not particularly limited. As a method for forming the transparent conductive film (2), various conventionally known methods, that is, a vapor deposition method, a sputtering method, or the like can be applied. When the electric field is applied from the outside of the transparent substrate (1), the transparent conductive film (2) can be omitted.

As the fine particles (3), any fine particles can be used as long as they can absorb light and form a fine particle aggregate by an electric field or a magnetic field.
There is no particular limitation.

Examples of such fine particles (3) include graphite, TiO _x (1 ≦ x ≦ 1.5), TiO _x N.
_y (1.37 ≦ x + y ≦ 1.95, 0.15 ≦ y ≦ 0.
92), TiO _x coated mica (1 ≦ x ≦ 1.5), Ti
O _x N _y coated mica (1.37 ≦ x + y ≦ 1.95, 0.
15 ≦ y ≦ 0.92), TiO _x coated glass flakes (1 ≦ x ≦ 1.5), TiO _x N _y coated glass flakes (1.37 ≦ x + y ≦ 1.95, 0.15 ≦ y ≦ 0. 9
2), γ-iron oxide, metal titanate, iron, cobalt, magnetite, barium ferrite and chromium dioxide (I
V) etc. can be mentioned.

As for the shape of the fine particles (3), the rod-shaped fine particle aggregate (4) obtained by applying an external field has a small absorption cross section for light in the direction perpendicular to the transparent substrate (1). For this reason, it is preferable to have a needle shape or a plate shape.

The size of the fine particles (3) has a short axis of 100 n in order to increase the light transmittance when an external field acts.
It is preferably m or less.

Further, when the fine particles (3) have conductivity, it is preferable to coat the fine particles (3) with a silica film in order to impart electric insulation.

As the fine particle dispersion liquid (5 '), the fine particles (3) to be dispersed and contained are easily dispersed to form the silicone resin film (5), and then the rod-shaped fine particle aggregate (4) is retained. In addition, those having excellent insulation and weather resistance are preferable. Specific examples thereof include a photocurable silicone material and a thermosetting silicone material.

Further, as the adhesive resin film (6) used for obtaining a sufficient adhesive force between the silicone resin film (5) and the transparent substrate (1), for example, Dumilan [trade name, Takeda Pharmaceutical Co., Ltd. Manufactured (four-dimensional copolymer produced by saponifying ethylene-vinyl acetate copolymer having a specific vinyl acetate group content and produced by a high-pressure method after a saponification reaction by a special method and then acid-modifying) ] A film, a polyvinyl butyral film, or the like can be used. The adhesive resin film (6)
Has a large polar force component of the surface tension, so that good adhesion with the transparent substrate (1) can be obtained. The adhesive resin film (6) also has a function as an adhesive intermediate film, and even if the transparent substrate (1) is destroyed by an external force, the transparent substrate (1) does not scatter. However, it is only useful in terms of safety, because it only cracks.

On the other hand, the dispersive force component is dominant as the surface tension component of the silicone resin film (5). Therefore, the surface of the silicone resin film (5) is subjected to an oxidation treatment to have a polar component, so that the adhesive force with the adhesive resin film (6) can be improved. Further, in the silicone resin film (5), the gel shrinks when subjected to an oxidation treatment, but the portion near the fine particle aggregate (4) does not easily shrink, so that an uneven shape is formed on the film surface. In the present invention, the adhesive force with the adhesive resin film (6) is improved by utilizing these characteristics of the silicone resin film (5).

As a method for oxidizing the surface of the silicone resin film (5), oxygen plasma treatment or the like can be used in addition to heat treatment in an oxidizing atmosphere. When the silicone resin film (5) is heat-treated, it is necessary to heat the silicone resin film (5) within the range of 200 to 300 ° C. so that at least the surface is oxidized. If the heat treatment temperature is less than 200 ° C,
No oxidation of silicone gel occurs. On the other hand, when the heat treatment temperature exceeds 300 ° C., oxidative decomposition of the silicone gel proceeds too much, resulting in separation from the transparent substrate surface.

Next, the method for evaluating the optical characteristics of the angle-selective light transmitting plate of the present invention will be described. FIG. 3 is an apparatus for explaining the measurement principle, and only the main parts are drawn. The measuring device comprises a light source (9) and a detector (10), and a sample (11) is arranged between the light source (9) and the detector (10) and on the line connecting the two. ,
Further, the center position in the lengthwise direction is clamped from both side surfaces by an auxiliary tool (not shown), and is further rotatable by a shaft.

As the light source (9), it is preferable to use a white light source containing each light component and capable of obtaining a parallel beam. The detector (10) is an optical-electrical converter that receives the detection light emitted from the light source (9) and converts the input optical signal into an electrical signal.

The surface of the sample (11) is irradiated with the detection light from the light source (9), and the angle formed by the normal line of the incident detection light and the normal line of the surface of the sample (11) is defined as the incident angle φ, and the sample (11). Is rotated clockwise, for example, by 5 ° about the axis, and the transmitted light intensity at each angle is detected by the detector (10).

[0027]

The angle-selective light-transmitting plate of the present invention has good angle-selectivity of transmittance, and at least the surface of the silicone resin film facing the adhesive resin film is subjected to oxidation treatment. Since it has excellent adhesiveness to a resin film, it can be suitably used as an energy-saving glass in applications such as construction and automobiles.

[0028]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples.

(Example) Needle-like T having an extinction coefficient of about 10 ⁵ cm ^-1 and a major axis length of about 0.5 μm (aspect ratio = about 10).
A silica film (film thickness 5 nm) was coated on the iO _x N _y fine particles by a liquid phase method, and this was mixed with a raw material solution of silicone gel (KE1052 manufactured by Shin-Etsu Chemical Co., Ltd .; solutions A and B). (Solution B) / (solution B / solution A = 2.5 (weight ratio)) to prepare a suspension having a fine particle content of about 1.5 wt%.

A glass substrate (300 mm × 100 mm, thickness 1.1 mm) with an ITO film (thickness 30 ± 10 nm) coated with silica (thickness about 500 nm) was suspended on the substrate using an applicator. The liquid is coated (layer thickness, about 50 μm) and a gap (about 400 μm) is placed on the suspension surface.
μm) is provided to face the ITO film and a planar electrode is provided, and a DC voltage of 950 V is applied between the electrode and the ITO film to form a fine particle aggregate, and then 2 ° C. at about 70 ° C.
The gelation reaction proceeded by heating for a time.

Further, the silicone resin film containing this fine particle aggregate is heated in air at 300 ° C. for 15 minutes,
The film surface was oxidized. The silicone resin film containing the obtained fine particle aggregate was observed by an optical microscope, and it was confirmed that the fine particle chain was maintained as it was even after the heat treatment.

Next, in order to bond the silicone resin film whose surface has been oxidized to the other glass substrate, a film of Dumilan (trade name: manufactured by Takeda Pharmaceutical Co., Ltd.) (thickness: about 20) is used.
It was sandwiched between opposing glass substrates with a thickness of 0 μm). This was introduced into a chamber, decompressed to about 30 Torr to remove bubbles, and further heated at 95 ° C. for 30 minutes for vacuum fusion to manufacture a laminated glass. This was used as a sample for evaluation.

The optical performance of the sample obtained in this example was measured using the apparatus shown in FIG. The result is shown in Figure 4.
Shown in. As is clear from the figure, the transmittance sharply decreased as the incident angle φ increased. Also, the incident angle φ =
Transmittance change width T for 0 ° and φ = 60 °
When (0 ° -60 °) was obtained, it was about 40%, and it was confirmed that the value was improved at least twice as compared with the value reported conventionally.

The symmetry of the transmittance with respect to the incident angle was very good. It is considered that this is because the fine particle aggregates grow vertically to the glass substrate surface.

Comparative Example A sample for evaluation was prepared in the same manner as in Example except that the surface of the silicone resin film was not oxidized.

The shear adhesive strength of each sample of the silicone resin film surface of this example, which was subjected to the oxidation treatment, and the untreated sample of the comparative example, was examined and found to be 0.985 kg.cm.
^-2 and 0.908 kg-cm ^-2 . Next, when the peeled surface of each sample was observed, peeling occurred at the interface between the silicone resin film and the adhesive resin film, which had the poorest adhesive strength in each layer structure in both samples. From these results, it was confirmed that the adhesive force on the film surface is improved by subjecting the silicone resin film surface to the oxidation treatment.

[0037]

As described above, the present invention contains a bonding resin film and a large number of rod-shaped fine particle aggregates between a pair of transparent substrates and faces at least the bonding resin film. Since the silicone resin film whose side surface is oxidized is laminated, it is possible to obtain an angle-selective light-transmitting plate having excellent adhesiveness while maintaining the angle selectivity with good transmittance.

Therefore, the angle-selective light-transmitting plate of the present invention can be suitably used as a highly safe energy-saving glass in applications such as construction and automobiles.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an angle-selective light transmitting plate of the present invention.

2A to 2D are explanatory views showing a manufacturing process of the angle-selective light transmitting plate of the present invention.

FIG. 3 is an explanatory diagram showing the measurement principle of the optical characteristic evaluation apparatus.

FIG. 4 is a graph showing the relationship between the incident angle and the transmittance of the angle-selective light transmitting plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent plate 2 Transparent conductive film 3 Fine particle 4 Fine particle aggregate 5 Silicone resin film 5'Fine particle dispersion liquid 6 Adhesive resin film 7 Gap 8 External electrode 9 Light source 10 Detector 11 Sample

Claims (4)

[Claims] 1. An adhesive resin film between a pair of transparent substrates,
A plurality of fine particles are arranged in a substantially constant direction and include a large number of fine particle aggregates formed in a rod shape, and at least the surface on the side facing the adhesive resin film is laminated with an oxidized silicone resin. An angle-selective light-transmitting plate characterized in that 2. The angle-selective light-transmitting plate according to claim 1, wherein the oxidation treatment is a heat treatment or an oxygen plasma treatment. 3. The angle-selective light-transmitting plate according to claim 1, wherein the fine particles are light-absorbing fine particles. 4. The fine particles are graphite or TiO.
_x (1 ≦ x ≦ 1.5), TiO _x N _y (1.37 ≦ x + y)
≦ 1.95, 0.15 ≦ y ≦ 0.92), TiO _x coated mica (1 ≦ x ≦ 1.5), TiO _x N _y coated mica (1.37 ≦ x + y ≦ 1.95, 0.15) ≤ y ≤ 0.9
2), TiO _x coated glass flakes (1 ≦ x ≦ 1.
5), TiO _x N _y coated glass flakes (1.37 ≦ x +
y ≦ 1.95, 0.15 ≦ y ≦ 0.92), γ-iron oxide, a metal titanate, iron, cobalt, magnetite, barium ferrite, and at least one selected from the group consisting of chromium (IV) dioxide. The angle-selective light-transmitting plate according to claim 1, which is a kind of fine particles.