JP3078925B2 - Light source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source having an incandescent body.

[0002]

2. Description of the Related Art Conventionally, filaments have been used as incandescent bodies in incandescent lamps. However, most of the radiant energy from general filaments is infrared, and the energy of visible light is small and the efficiency is low. There is. As an incandescent lamp that solves such a problem, as shown in FIG. 6, a configuration in which a reflecting plate 4 is disposed in the vicinity of a filament 1a as an incandescent body is considered (Japanese Patent Laid-Open No. 56-1).
06364). The reflection plate 4 reflects the light emitted backward from the filament 1a forward and reflects the infrared light emitted from the filament 1a to the filament 1a.
By returning to, there is a function of improving the radiation efficiency of visible light. Therefore, the smaller the distance between the reflector 4 and the filament 1a, the higher the efficiency.

[0003]

By the way, the temperature of the filament 1a is as high as 2000-3000 ° K. If an aluminum vapor deposition film is used for the reflection plate 4, it has a high reflectance but low heat resistance. From filament 1a
Cannot be approached. Therefore, a high melting point metal is used for the reflection plate 4. On the other hand, since the reflection plate 4 formed of a high melting point metal has a low reflectance, if the reflection plate 4 is disposed close to the filament 1a, the temperature of the reflection plate 4 becomes high and infrared rays are radiated from the reflection plate 4. Since the reflector 4 has a larger surface area than the filament 1a, the amount of infrared light radiated from the reflector 4 is large, and the provision of the reflector 4 causes a problem that the efficiency is rather lowered.

An object of the present invention is to solve the above-mentioned problems, and to arrange a reflector near an incandescent body,
An object of the present invention is to provide a light source in which the radiation efficiency of visible light is improved by suppressing the amount of infrared radiation from a reflector.

[0005]

According to the first aspect of the present invention, in order to achieve the above object, the incandescent body is a filament, and the reflector has an opening diameter of at least one of the front and back surfaces.
Many cavities of less than nm are formed over the whole surface, and a plurality of reflectors are arranged in layers.

According to the second aspect of the present invention, there is provided a light emitting plate in which a large number of cavities having a fine opening dimension are formed over substantially the entire surface so that the incandescent body blocks light in a wavelength region of a predetermined wavelength or more. The reflection plate has an opening diameter of at least one of the front and back surfaces.
A large number of cavities of 000 nm or less are formed over the entire surface, and a plurality of reflectors are arranged in layers.

[0007]

According to the first aspect of the present invention, a plurality of reflectors having a large number of fine cavities formed on at least one surface of the front and back surfaces are disposed near the filament, and the reflectors are disposed in layers. Since a large number of fine cavities are formed on the surface of the reflection plate, the cavities function as a filter and block light having a wavelength about twice the aperture diameter. That is, the opening diameter of the cavity formed in the reflection plate is 1000 nm.
From the following, light in the infrared region having a wavelength of 2000 nm or more is cut off and not emitted from the reflector.

The function of the reflector will be described in more detail. The phenomenon of selective radiation due to fine cavities is disclosed in
It is known in, for example, Japanese Patent Application Publication No. 102701. For example, as shown in FIG. 3, when a large number of fine cavities are formed on one surface of a flat light emitting plate 1 (for example, the thickness t is 0.1 mm or less, the width W is 5 mm, and the length L is 25 mm or less). When the light emitting plate 1 is heated, the wavelength range of light emitted from the light emitting plate 1 can be limited. That is, as shown in FIGS. 4 and 5, the light radiating plate 1 has a large number of fine cavities 2 on the surface. When such cavities 2 are formed, the radiation field of light in the cavities 2 is increased. Due to the quantum electrodynamic effect that the probability of the existence of photons having energy less than a predetermined energy is significantly reduced, light in a wavelength region equal to or more than a predetermined wavelength can be blocked. That is, electrons and photons always interact in the cavity 2, but photons with a predetermined energy or less have a very low existence probability and are not observed within a finite time.

If the effect of the cavity 2 is interpreted in the classical physics, the cavity 2 can be regarded as a waveguide with low tuning. Therefore, it can be considered that transmission of light in a wavelength region equal to or longer than the cutoff wavelength among the electromagnetic waves radiated from the light emitting plate 1 is prohibited. If the cut-off wavelength is set to a size that blocks light in a region longer than visible light, that is, light in the infrared region, the emission of infrared light from the light emitting plate 1 can be suppressed.

As described above, by arranging a light emitting plate having such a cavity near the filament as a reflecting plate, even if the temperature of the reflecting plate becomes high, it is difficult for the reflecting plate to emit infrared rays. Energy loss due to infrared radiation from the plate can be greatly reduced. As a result, the efficiency as a whole is improved. By the way, if a reflector having a minute cavity as described above is used, the amount of infrared radiation from the reflector is suppressed, but infrared rays are radiated, so that a plurality of reflectors are arranged in layers. Accordingly, infrared rays emitted from the reflector near the filament can be blocked by the reflector far from the filament, and the amount of infrared radiation to the outside can be reduced to improve efficiency.

According to the second aspect of the present invention, the light emitting plate having the above-described minute cavity is used as the incandescent body. As a result, the amount of infrared rays emitted from the incandescent body can be suppressed.
Combined with the function of the reflector, the amount of infrared radiation to the outside can be further reduced. In particular, this type of light emitting plate is formed in a flat plate shape, and it is difficult to form fine cavities on both sides of the light emitting plate at the current technical level, so cavities are formed only on one side. At present, infrared rays are radiated from the other surface, but since the reflector is used in combination, the amount of infrared radiation to the outside can be greatly reduced.

[0012]

【Example】

(Embodiment 1) As shown in FIG. 1, a spherical tube 3 made of a light-transmitting material such as glass is provided. Inside the tube 3, a filament 1a as an incandescent body is disposed. A base 5 is attached to a part of the tube 3. The filament 1a is supported by a lead wire 6 fixed to a base 5.
A plurality of plate-like reflectors 4 are arranged in layers near the base 5 near the filament 1a. The reflection plate 4 is supported by a support 7 fixed to the base 5. Each reflecting plate 4 is formed of a high melting point metal such as tungsten, and a large number of fine cavities having an opening diameter of 1000 nm or less are formed on one surface of the front and back surfaces of the reflecting plate 4.

Although the case where the number of layers of the reflector 4 is two is illustrated, the number of layers is not particularly limited. If the number of layers is four or more, the surface on which the fine cavities are formed in all the reflection plates 4 is defined as the filament 1a side.
When the number of layers is less than the number of layers, the effect is high when only the reflector 4 farthest from the filament 1a is oriented so that the surface on which the cavity is formed is opposite to the filament 1a. However, the direction of the reflection plate 4 is not particularly limited, since there is an effect of reducing the amount of infrared radiation regardless of which direction the surface having the cavity is formed with respect to the filament 1a. If it is technically possible to form a cavity on both sides of the reflector 4, the cavity may be formed on both sides of the reflector 4. In addition, even if the reflection plate 4 is a single layer, there is an effect of increasing the efficiency as compared with the case where the reflection plate 4 is not provided.

(Embodiment 2) In this embodiment, as shown in FIG. 2, a flat light emitting plate 1b having a fine cavity formed on the surface is used as an incandescent body instead of a filament. It is different from 1. That is, as shown in FIG. 3, the light emitting plate 1b is formed in a plate shape from a high melting point metal such as tungsten or molybdenum, and an opening is formed on the surface of the light emitting plate 1b as shown in FIGS. Many fine cavities 2 having a square shape are formed on the surface. Further, in order to suppress the emission of infrared rays, the cutoff wavelength of each cavity 2 is set to 700 nm or the like, and the dimension a of one side of the opening cross section of the cavity 2 is set to 350 nm as a design condition satisfying the cutoff wavelength. The distance d between the adjacent cavities 2 is set to, for example, 100 nm in order to make it equal to or less than the skin depth for a wavelength of 700 nm. That is,
Each cavity 2 functions independently as a waveguide,
The connection of the cavity 2 prevents the cutoff wavelength from becoming longer. Further, the depth D of the cavity 2 is set to, for example, 7000 nm.

If the light emitting plate 1b having such a configuration is used, the amount of infrared radiation radiated forward is greatly reduced, and the efficiency is improved. Although the cavity 2 is not formed on the back surface side of the light emitting plate 1b due to technical difficulty, the infrared light emitted backward is reflected forward by the reflector 4, so that the infrared light as a whole is Very little light is emitted and a very efficient light source can be provided. Other configurations are the same as in the first embodiment.

[0016]

According to the present invention, as described above, a plurality of reflectors having a large number of fine cavities formed on at least one surface of the front and back surfaces are arranged near the incandescent body, and the reflectors are arranged in layers. Because of this, a large number of fine cavities formed on the surface of the reflection plate function as a filter, and can block light having a wavelength about twice the aperture diameter. Moreover, since the opening diameter of the cavity formed in the reflection plate is 1000 nm or less, light in the infrared region is blocked, and the effect of increasing the efficiency is exhibited. When the incandescent body is a filament, the efficiency is 20% or more when the incandescent body is a filament, and the efficiency is 60% or more when the incandescent body is a light emitting plate having fine cavities on the surface. became.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment.

FIG. 2 is a side view showing a second embodiment.

FIG. 3 is a perspective view showing a light emitting plate used in a second embodiment.

FIG. 4 is a plan view showing a light emitting plate used in the present invention.

FIG. 5 is a sectional view showing a light emitting plate used in the present invention.

FIG. 6 is a side view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-emitting plate 1a Filament 1b Light-emitting plate 2 Cavity 3 Tube 4 Reflector

Claims (2)

(57) [Claims] 1. A light source in which a reflector that reflects radiation light from an incandescent body disposed inside a tubular body to the incandescent body side is disposed close to the incandescent body, wherein the incandescent body is a filament; The reflector has an opening diameter of at least one surface on both sides.
A light source, comprising: a plurality of cavities each having a size of nm or less formed over the entire surface; and a plurality of reflectors arranged in layers. 2. A light source in which a reflection plate for reflecting radiation light from an incandescent body disposed inside a tubular body to the incandescent body side is disposed close to the incandescent body, wherein the incandescent body has a wavelength of a predetermined wavelength or more. A light emitting plate in which a large number of cavities having an opening size fine enough to block light in a region are formed over substantially the entire surface, and the reflecting plate has a large number of openings with a diameter of 1000 nm or less on at least one of the front and back surfaces. A light source, wherein a plurality of reflectors are arranged in a layered manner.