JPH0817216A - Daylighting device - Google Patents

Abstract

PURPOSE:To decrease the quantity of beam reflected on the surface of each of prism plates in the daylighting part of a daylighting device which daylights from the sun for use for lighting, heating, etc., and to increase the quantity of the transmitted light. CONSTITUTION:A daylighting device is constructed in such a manner that its daylighting part 1 may have daylighting elements having antireflection treatment preventing beams from being reflected on their surfaces given thereto. Members used for the respective elements are at least two daylighting prism plates 2, 3 each being independently rotatable in its horizontal direction. And the antireflection treatment is given to the plates 2, 3 in such a manner that each of the plates 2, 3 may be coated with at least the monolayer of a fluorine group antireflection film 4 of constant thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to lighting, heating, etc., and more particularly to improvement of a daylighting device for collecting light rays from the sun for use in lighting, heating, etc.

[0002]

2. Description of the Related Art Conventionally, as a daylight collecting device for collecting sunlight, as shown in Japanese Patent Laid-Open No. 61-180217, at least one prism plate is rotated while two prism plates or Fresnel prisms are stacked. By doing so, a direct light ray from the sun is sent out in a fixed direction regardless of the position of the sun (an antireflection film is not shown in FIG. 1, which will be described later).

[0003]

However, in the above-mentioned Japanese Patent Laid-Open No. 61-180217, the surface reflection of the prism plate, which is the light-collecting portion, is large, and the surface reflection increases as the number of prism plates through which light rays pass increases. However, there is a drawback that the effective amount of transmitted light is reduced due to the increase of the above, and it has been desired to reduce the surface reflection.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention prevents the surface reflection of light rays at a light collecting portion in a daylight collecting device that collects light rays from the sun for use in lighting, heating, etc. Provided is a daylighting device having a daylighting element that has been subjected to antireflection treatment, wherein the daylighting element is at least two independently-rotatable daylighting prism plates, and the antireflection treatment is performed using a fluorine-based antireflection film. The thickness is such that at least a single layer is coated.

[0005]

First, the reflection of light will be described with reference to FIG.

In FIG. 2, light of wavelength λ is generally air A.
In the (refractive index n0 = 1) direction, the thickness of the thin film B that maximizes the antireflection effect when hitting the substrate C (refractive index n2) coated with the thin film B (refractive index n1) is determined. It is known that when t, t = λ / 4n1 ... (1), and the closer to n1-n0 = n2-n1 ... (2), the less the reflection. Therefore, a preferable antireflection effect can be obtained by selecting a substance satisfying these equations.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a daylighting device according to the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic explanatory view of a daylighting device, FIG. 2 is an explanatory view of light reflection, FIG. 3 is a graph of a surface reflectance calculation result by a surface reflection simulation, and FIG. 4 is a transmittance actual measurement result of a daylighting prism plate. Is a graph of.

In FIG. 1, a daylighting section 1 is composed of an upper daylighting prism plate 2 and a lower daylighting prism plate 3, both made of polycarbonate (abbreviated as PC), and the upper and lower surfaces thereof are covered with a fluorine-based antireflection film 4. And the vertical center axis O-O
Each of them can rotate independently.
The light 5 from the sun is directed downward as indicated by an arrow 6 even if the height of the sun is changed by rotating the upper light collecting prism plate 2 and the lower light collecting prism plate 3, respectively.

That is, the daylighting device according to the present invention is a daylighting device that collects light rays from the sun for use in lighting, heating, etc. The element includes an upper light collecting prism plate 2 and a lower light collecting prism plate 3 each of which is independently rotatable in the horizontal direction, and the antireflection treatment includes a fluorine-based antireflection film 4. At least a single layer is coated with a constant thickness.

The conditions for the above-mentioned daylighting device, the surface reflection simulation, and the actual measurement results of the transmittance of the daylighting prism plate will be described below.

(A) Conditions The upper prism plate is 0 ° / 42 °, that is, the upper face is flat and the lower prism apex angle is 42 ° (see FIG. 1), and the lower prism plate is 0 ° / 51.48 °, antireflection Film (see Fig. 2) B is a fluorine-based antireflection film "CYTO" from Asahi Glass Co., Ltd.
P ”, refractive index 1.34, He-Ne instead of sunlight
Since the laser (d line, λ = 588 nm) was used, the film thickness t = λ / 4n1 = 588/4 × 1.34 (about 110 nm) from the equation (1).

(B) Surface reflection simulation (see FIG. 3) As a result of calculating the reflectance on the PC surface, the surface reflectance is reduced by about 5 points for each interface regardless of the incident angle.

(C) Results of actual measurement of transmittance of the daylighting prism plate (see FIG. 4).
Alternatively, by rotating both the upper and lower prism plates, the arrow 6 (see FIG.
(See), the light beam is controlled so that it is directed downward, and the output energy with respect to the incident energy is measured.
By coating an antireflection film, the transmittance is improved by about 6 points.

(D) Incidentally, PC (n2 = 1.
583) and polymethyl methacrylate (abbreviated as PMMA, n2 = 1.492) are compared, the above formula (2) shows that in the case of PC, n2-n1 = 1.5833-1.34 = 0. In the case of 243 PMMA, n2-n1 = 1.492-1.34 = 0.152, and in the case of PC n1-n0 = 1.34 = 1 = 0.3
Although it is close to 4 and the antireflection effect is large, (b)
The reflectance calculated by the term is only 3.5 points in the case of PMMA.

[0016]

EFFECT OF THE INVENTION Fluorine-based antireflection film (amorphous polymer)
Unlike the conventional distillation method, the coating can be performed by spin coating or dip coating simply and in a short time, so that the above-described antireflection and thus the increase in transmittance can be obtained relatively inexpensively.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of a daylighting device according to the present invention.

FIG. 2 is an explanatory diagram related to light reflection.

FIG. 3 is a graph showing calculation results of surface reflectance by surface reflection simulation.

FIG. 4 is a graph of the actual measurement results of the transmittance of the daylighting prism plate.

[Explanation of symbols]

 1 Light collecting unit 2 Upper light collecting prism plate 3 Lower light collecting prism plate 4 Fluorine-based antireflection film t Film thickness

Claims (4)

[Claims] 1. A daylighting device for collecting light rays from the sun for use in lighting, heating, etc., wherein the daylighting part has a daylighting element subjected to antireflection treatment for preventing surface reflection of the light rays. . 2. A lighting device for collecting light rays from the sun for use in lighting, heating, etc., wherein the lighting portion has a lighting element subjected to an antireflection treatment for preventing surface reflection of the light rays, and the lighting element is at least A daylighting device comprising two light-collecting prism plates that can rotate independently in the horizontal direction. 3. A lighting device that collects light rays from the sun for use in lighting, heating, etc., has a lighting element that has been subjected to antireflection treatment for preventing surface reflection of the light rays in the lighting portion, and the antireflection treatment is A daylighting device, characterized in that a fluorine-based antireflection film is coated at least in a single layer with a constant thickness. 4. A lighting device for collecting light rays from the sun for use in lighting, heating, etc., wherein the lighting portion has a lighting element subjected to an antireflection treatment for preventing surface reflection of the light rays, and the lighting element is at least 2. A daylighting device, comprising two light-collecting prism plates that can be independently rotated in the horizontal direction, and in which the antireflection treatment covers at least a single layer of a fluorine-based antireflection film with a constant thickness.