JPS6275402A - Projection type multilayer film reflector - Google Patents

Abstract

PURPOSE:To remove a color glass filter and to prevent the surface of a reflector from damage by coating a multilayer film having film thickness enabling a specific color beam to reflect and project to the surface of the projecting reflector. CONSTITUTION:Since the projection type multilayer film reflector is constituted by coating the multilayer film 2 having selected film constitution and film thickness enabling a specific beam to reflect and project to the surface of the projection reflector 1 by projected illumination, various kinds of color beams having reflection bands in a specific wavelength area can be projected. Consequently, the use of a color glass filter can be removed and the surface of the reflector can be prevented from damage due to heat because a heat wire can be transmitted from the back of the reflector.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a floodlight type multilayer film reflector that makes it possible to project light of a specific color without using a single-color filter or the like in a floodlight.

[Technical background of the invention and its problems]

Conventionally, a lighting device as shown in FIG. 9 has been employed for flood lighting such as a spotlight. That is, metal aluminum is deposited on the inner surface of a glass reflector (a) by vapor deposition means to form a reflective mirror surface (b), light from a light source (c) is reflected on the reflective mirror surface (b), and the reflector Reflected light was projected through a colored glass filter (d) placed in front of (a). Therefore, this lighting device had the following problems.

1. A mounting device is required to attach and detach the colored glass filter (d).

2. The colored glass filter (d) is subject to strong heat rays caused by reflected light and is frequently damaged, making it extremely difficult to replace it.

3. The reflective surface (b) of the reflector (a) is the light source (c)
It is easily damaged by the heat rays.

[Purpose of the invention]

The present invention has been made in order to eliminate the various problems mentioned above, and is a light projection multilayer film that enables reflection and projection of a specific color by the reflection mirror itself, eliminates the need for colored glass filters, and prevents damage to the reflection mirror surface. The purpose is to provide a reflective mirror.

[Summary of the invention]

A multilayer film having a selected configuration and film thickness that enables reflection and projection of a specific color is coated on the light projection reflector surface.

[Embodiments of the invention]

In general, this kind of multilayer reflector is made by alternately laminating thin films of high refractive index material and low refractive index material on the inner surface of a glass reflector to form a multilayer film, and the more layers there are, the higher the reflectance. In addition, the larger the ratio of the refractive indexes of the laminated materials, the wider the reflection band.

For example, when zinc sulfide with a refractive index of 2.3 is used as a high refractive index material, and magnesium fluoride with a refractive index of 1.38 is used as a low refractive index material in combination (the ratio of the refractive index is 1.67). The reflectance characteristics are shown in FIG. 1, and the film structure and film thickness are shown in Table 1.

Here, the optical thickness of each substance is 1/4λ.

That is, as is clear from FIG. 1, the more layers there are, the higher the reflectance and the sharper the reflection characteristics. Also the second
The figure shows the spectral reflectance characteristics (transmittance ratio is 1.41) when zinc sulfide with a refractive index of 2.3 is used as a high refractive index material and alumina with a refractive index of 1.63 as a low refractive index material. Table 1-2 shows the film structure and film thickness at that time. The film thickness of each substance is 1/4λ of the optical film thickness, and the design wavelength is 550 nm. Furthermore, it can be seen from FIGS. 1 and 2 that the larger the ratio of refractive indexes, the wider the reflection band.

The present inventors focused on the above-mentioned points and found that it is possible to reflect and project light in a specific color by selecting the film structure and film thickness of a film material that reflects a limited range in the visible range. .

The details of the present invention will be explained below with respect to each embodiment.

In Figure 3, (1) is a glass floodlight reflector, (2
) indicates a multilayer film, and (3) indicates a light source. First, as a first example, the structure and thickness of a multilayer film adapted to blue light projection will be described. Generally, in the visible range, blue is located between 400 nm and 500 nm, and to obtain blue reflection, the wavelength is 500 nm.
High reflectance and sharp reflection characteristics are required in order to have a reflection band below nm and to emit clear blue light. Note that even if the reflection band is extended to the ultraviolet region of 400 nm or less, it will not be a problem because it will not be felt by the naked eye. FIG. 4 shows the spectral transmittance curve of a reflecting mirror in which the blue projection type multilayer film (2) is coated on the surface of the projection reflector (1), and Table 1-3 shows the film structure and film thickness.

That is, zinc sulfide (ZnS) is used as a high refractive index film, and silicon oxide (Si02) with a refractive index of 1.46 is used as a low refractive index film.
), and the ratio of their refractive indexes is 1.58. Further, the design wavelength λ of the film thickness was set to 430 nm. Further, as is clear from the figure, since the heat rays from the light source (3) are transmitted through the back surface of the projection reflector (1), the reflective surface is not heated. Therefore, it is possible to reduce heating of the object to be illuminated by the heat rays.

As a second example, the fifth example is for the case of yellow reflection.
This will be explained with reference to Figure and Table 4. In order to obtain yellow reflection, it is required to have a reflection band in the range of 550 nm to 750 nm and a high reflectance in the range of 570 nm to 630 r+m, and to obtain even clearer light projection, it is required to have sharp reflection characteristics. is also required. The film structure was the same as in the first example, but the film thickness was set at a design wavelength λ2 of 650 nm.

In addition, even in this yellow projecting multilayer reflector, the first
As in the embodiment described above, since the heat rays from the light source are transmitted through the back surface of the projection reflector, the reflecting surface is not heated, and heating of the illuminated object by the heat rays can be reduced.

As a third example, red reflection will be described.

First, in order to obtain red reflected light, it is necessary to have a reflection band at 630 nm or more, but even if the reflection band extends to the infrared region, this is not a problem because it cannot be felt with the naked eye.

However, the energy distribution of the light source is 1, OOO
Since it has a strong peak in the vicinity of nm, if it has a wide reflection band, the reflection surface may be heated by the heat rays from the light source and may be damaged. Therefore, it is ideal to have a reflection band in the range of 630 nm to 850 nm, and high reflectance and sharp reflection characteristics are required in order to project clear red light. Figure 6 shows the spectral transmittance curve of a reflective mirror actually coated with a multilayer film, and Table 5 shows its film structure and film thickness.The design wavelength λ3 is 720 nm.
It is I11.

Also, in this red light projecting multilayer reflector, the above-mentioned first. As in the second embodiment, heat rays are transmitted through the back surface of the reflector, thereby eliminating thermal effects on the object to be illuminated. As another example, the spectral transmittance of a green projecting multilayer reflector is shown in FIG. 8, and the film structure and film thickness are shown in Table 7. This green reflection is between 500nm and 570nm.
It is necessary to have a narrow reflection band, high reflectance, and sharp reflection characteristics. In this case, it is difficult to construct a reflection band to obtain green reflection. However, this is possible by adopting a special configuration as shown in FIG. 7 and Table 6, but with this film thickness configuration, a wide reflection band appears in the infrared region, and there is a risk that the reflective surface may be damaged by heat rays. Therefore, when a narrow reflection band such as green reflection is required, it is necessary to select a material with a small refractive index ratio.

Therefore, by using zirconium oxide with a refractive index of 2.05 as the high refractive index film and alumina with a refractive index of 1.63 as the low refractive index film shown in Figure 8 and Table 7, the refractive index ratio can be set to 1.26. Then, the design wavelength λ may be set to 550 nm and the light emitting reflector may be coated.

(Left below) Table-1 λ, = 50nm λ, = 430
nm [Effects of the Invention] As described in detail above, the present invention provides a multilayer film having a selected film structure and film thickness on the surface of a floodlight reflector in a floodlight to enable reflection and projection of specific light. Is it possible to use a colored glass filter that can project various colored lights with reflection bands in specific wavelength ranges? Can be eliminated. Furthermore, since the heat rays can be transmitted through the back surface of the reflector, it has various advantages such as preventing damage to the reflecting mirror surface due to heat.

[Brief explanation of drawings]

Figure 1 is a curve diagram showing the spectral reflectance characteristics based on theoretical calculations of each layer in the ZnS-MgFz configuration, and Figure 2 is a curve diagram showing the spectral reflectance characteristics of each layer in the ZnS-MgFz configuration.
A curve diagram showing the theoretically calculated spectral load-bearing characteristics of 11 layers in the Ω203 configuration, Figure 3 is a cross-sectional view of a light projection reflector in the third embodiment of the present invention, and Figure 4 is a curve diagram showing a light projection reflector coated with a pre-light projection type multilayer film. Curve diagram showing the spectral transmittance characteristics of the case, No. 5
Figure 16 is a curve diagram showing the spectral transmittance characteristics when three yellow floodlight multi-layer films are deposited, Figure 16 is a curve diagram showing the spectral transmittance characteristics when a red floodlight multilayer film is deposited, and Figure 7 The figure shows Zn
S-5in, a curve diagram showing the spectral reflectance characteristics based on theoretical calculations when a special film thickness configuration is adopted in the configuration, and Figure 8 is a curve diagram showing the spectral transmittance characteristics when a green light-emitting multilayer film is applied. FIG. 9 is a sectional view of a lighting device showing a conventional example.

Claims (1)

[Claims] 1. A light projecting multilayer film reflector, characterized in that a multilayer film having a selected configuration and film thickness is coated on a light projecting reflector surface to enable reflection and projection of a specific color.