JPH0582107A - Halogen lamp having dichroic mirror - Google Patents

Abstract

PURPOSE:To improve a color rendering property and a light-proof characteristic by arranging a halogen lamp housing a vertical type filament inside of a dichroic mirror, and providing an interference filter on the front glass inside surface of the mirror. CONSTITUTION:When lamp voltage is impressed between power receiving pins 21a and 21b, a vertical type filament 18 emits light spontaneously, and it is radiated to a visible radiation reflecting infrared ray transmittable film 15 of a dichroic mirror 12 and an interference filter 24. The dichroic mirror 12 transmits infrared rays, and releases heat, on the one hand, it reflects visible radiation so as to be radiated to the interference filter 24. The interference filter 24 is formed, so that a wave length among incident light can have a reflection peak with 650 (nm) as its center. In this constitution, both a color rendering property and a light-proof characteristic can significantly be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halogen light bulb with a dichroic mirror suitable for spotlights for shops,
In particular, it relates to a halogen light bulb with a dichroic mirror having an improved front glass.

[0002]

2. Description of the Related Art Conventionally, a halogen light bulb 1 with a dichroic mirror of this kind is provided in a bowl-shaped dichroic mirror 2.
It contains a halogen bulb 3.

In the dichroic mirror 2, a parabolic inner peripheral surface of a bowl-shaped transparent glass substrate 4 is covered with a visible light-reflecting infrared ray transmitting film 5 that reflects visible light and transmits infrared rays almost entirely. , Its front open end is closed by a front glass 6.

On the other hand, the halogen light bulb 3 has a vertical filament 8 formed in a coiled cylindrical glass bulb 7 along the axial direction of the bulb.

By the way, in order to give a high color rendering property to the object to be irradiated, it is more preferable to irradiate light having a high color temperature of 3600 K or higher, which is closer to natural light, but it is obtained by the conventional halogen bulb 1 with a dichroic mirror. In order to achieve this, a method of replacing the front glass 6 with a color temperature change filter made of colored glass, and a method of reducing the red component reflected light of the dichroic mirror 2 to increase the color temperature by the dichroic mirror 2 itself Etc. have been put to practical use.

[0006]

However, in the former case as described above, the illuminance is lowered due to the low transmittance of the colored glass. Further, since the heat resistance is low, the dichroic mirror 2 has to be upsized, which causes a problem of cost increase.

The latter is to absorb and transmit the infrared component to the rear of the dichroic mirror 2 by changing the film structure of the interference filter of the dichroic mirror 2. For this reason, the number of film layers of the interference filter is limited due to the cost of the interference filter. Therefore, an ideal reflection characteristic cannot be obtained by the interference filter having the infrared cut function and the color temperature conversion function. As shown, some unevenness is formed.

Further, the incident angle of light to the dichroic mirror 2 is not constant, and there is a problem that it is difficult to make the light color and color temperature uniform on the irradiation surface due to the incident angle dependency of the interference filter. These problems become more remarkable as the dichroic mirror 2 becomes smaller.

That is, when the color temperature is increased by the dichroic mirror 2 itself, the light color and the color temperature on the irradiation surface greatly vary.

Therefore, the present invention has been made in consideration of such circumstances, and an object thereof is to provide a halogen bulb with a dichroic mirror capable of improving color rendering.

[0011]

The first invention of the present application was made in view of the fact that the color rendering property can be improved by reducing the light having a wavelength of 650 nm and its surroundings. Is composed of.

The invention according to claim 1 of the present application (hereinafter referred to as the first invention) is a front surface of a dichroic mirror having a parabolic inner surface formed with a visible light reflecting infrared reflecting film for reflecting visible light and transmitting infrared rays. Halogen bulb with a dichroic mirror that has a halogen glass bulb inside with the open end closed by a front glass and a vertical filament that is coiled along the axial direction of the mirror. In, on the inner surface of the front glass,
It is characterized in that an interference filter is formed to reduce light having a wavelength of about 650 nm and its periphery.

The invention according to claim 2 of the present application (hereinafter referred to as the second invention) is a dichroic mirror having a parabolic inner surface formed with a visible light reflecting infrared reflecting film for reflecting visible light and transmitting infrared rays. The front open end of is closed by a front glass, and a halogen bulb is built in the inside, and in the spherical bulb of this halogen bulb, a vertical filament formed in a coil shape along the axial direction of the mirror. In a halogen bulb with a built-in dichroic mirror,
A light reflection film is formed on at least a tip end surface of the bulb, which is at a position ahead of a surface connecting a center of the filament and an opening end of the front surface of the mirror.

[0014]

[Action]

<First Invention> Light emitted from a halogen bulb is directly or after being reflected by a dichroic mirror, applied to an interference filter on a front glass. The interference filter has a wavelength of about 6
The light around 50nm and its periphery is reduced and transmitted.
Irradiate the front irradiation surface. Light having a wavelength of 650 nm and light around the wavelength is light that deteriorates the color rendering property. Therefore, the color rendering property can be enhanced by reducing this light with an interference filter.

<Second Invention> Since the halogen bulb has a reflective film formed on the front end surface of its spherical bulb, the light emitted from the filament behind the reflective film is reflected or diffused by the reflective film and the inside of the bulb. Part of the light is returned to the filament, and the other is reflected again by the dichroic mirror to irradiate the front irradiation surface.

That is, since the light which is about to be emitted from the filament toward the area other than the front irradiation surface is reflected or diffused by the reflection film on the front surface of the bulb, and further reflected by the dichroic mirror to be irradiated on the front irradiation surface, Since most of the light emission of (1) can be intensively applied to the front irradiation surface, the central luminous intensity of the front irradiation surface can be increased and the light distribution characteristics can be improved.

<Third Invention> Since the halogen light bulb with a dichroic mirror of the first or second invention has an infrared reflection film formed on the inner peripheral surface of the halogen light bulb, the light emitted by the filament in the halogen light bulb is used. Of these, the infrared rays of the heat rays are reflected by the infrared reflection film and return to the filament to heat it. Therefore, the luminous efficiency of the filament can be increased.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the first and second inventions of the present application will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of an embodiment of the first invention of the present application. In the figure, a halogen bulb 11 with a dichroic mirror is a spheroid and a bowl-shaped dichroic with a beam angle set to, for example, 12 °. A halogen bulb 13 is built in the mirror 12.

The dichroic mirror 12 is provided with a visible light reflection / transmission film 15 for reflecting visible light and transmitting infrared rays on substantially the entire inner peripheral surface of a bowl-shaped transparent glass substrate 14, and an insertion hole at the center of the bowl-shaped bottom. 16a is provided and this insertion hole 16
A sleeve-shaped neck portion 16 is integrally provided at the outer end of a so as to project outward in the horizontal direction.

On the other hand, the halogen bulb 13 has a vertical filament 18 in which a vertical filament 18 is incorporated together with an appropriate amount of halide and a rare gas in a bulb 17 having a glass lid and having a cylindrical shape. The filament 18 is formed in a coil shape along the axial direction of the cylindrical valve 17 and has a vertical structure.
8, a pair of upper and lower legs 19a, 1 are provided at the left and right ends in FIG.
9b is connected.

The pair of legs 19a, 19b are a pair of molybdenum foils 20 embedded in the sealing end 17a of the valve 17.
It is connected to the pair of power receiving pins 21a and 21b via a, 20b and the like.

The halogen bulb 13 has its sealed end portion 17a inserted into the neck portion 16 of the dichroic mirror 12 and filled with an adhesive 22 such as cement to be fixed.

The dichroic mirror 12 has its front open end closed by a front glass 23, and an interference filter 24 is formed on almost the entire inner surface of the front glass 23.

The interference filter 24 includes a TiO ₂ layer and a SiO ₂ layer.
A plurality of layers are alternately laminated to reduce light of, for example, ± 10% around a wavelength of 650 nm.

Next, the operation of this embodiment will be described.

When a required lamp voltage is applied between the pair of power receiving pins 21a and 21b, the vertical filament 18 emits incandescent light, and the emitted light is emitted from the visible light reflecting infrared ray transmitting film 15 of the dichroic mirror 12 and the interference filter 24. Is irradiated.

In the dichroic mirror 12, infrared rays, which are heat rays, of the incident light are transmitted to be radiated to the outside to radiate heat, while visible light is reflected and applied to the interference filter 24.

The interference filter 24 is formed so as to have a reflectance peak in the wavelength of 650 nm (650 nm ± 10%) of the incident light (at least 50% reflectance at 650 nm).

FIGS. 2B and 3 show the spectral distribution of the central portion of the irradiation surface 1 m away from the front glass 23 in this embodiment, and the conventional dichroic mirror without the interference filter 24 is shown. Halogen bulb 1 (Fig. 11
The spectral distribution of (see) is shown in FIG. Further, in Table 1 below, the color rendering properties and color temperatures of this example and the conventional example are shown in comparison.

[0031]

[Table 1]

According to Table 1, the color temperature of this embodiment is 3838K and that of the conventional example is 3883K, both of which are almost the same, but in the visible light region where the wavelength affecting the color rendering property is 650 nm or less. (B), as shown in FIG. 3, the present embodiment shows a curve substantially close to a black body locus, whereas the spectral distribution curve of the conventional example has a wavelength of 65 as shown in FIG. 2 (A).
The reflectance around 0 nm is high, showing unevenness, showing a remarkable difference.

In other words, as shown in Table 1 above, since the red light rays Ra and R9 to R15 are improved in this embodiment, the color rendering property of this embodiment is improved as compared with the conventional example. Has been done.

The reason why the color temperature does not decrease can be considered as follows. That is, considering light emitted from one point F on the filament 18 as shown in FIG. 1, visible light of the light emitted from the point F to one point A on the dichroic mirror 12 is reflected here and then the interference filter 24. Is incident on. When the interference filter 15 is a normal visible light reflecting / infrared transmitting film, the visible light region, for example, 38
Reflects flat around 0 to 700 to 780 nm. This reflected light is incident on the interference filter 24, and 650
This is because light near nm will be cut.

Therefore, according to this embodiment, the color temperature distribution and the color rendering properties can be improved. FIG. 4 is a vertical cross-sectional view of another embodiment. In the figure, a halogen light bulb 31 with a dichroic mirror is characterized in that reinforcing films 32, 32 are formed on both inner and outer surfaces of a front glass 23. Since it is the same as the above-mentioned embodiment except that 24 is omitted, in FIG. 4, the same parts as those shown in FIG. 1 are designated by the same reference numerals to simplify the description of the overlapping parts, or Omitted.

In the conventional halogen light bulb 1 with a dichroic mirror shown in FIG. 10, the front glass 6 is usually 2 to 3 mm.
A thick hard glass is used, and further, it is formed into a curved surface so as to withstand the impact at the time of rupture of the halogen light bulb 3, thereby improving the mechanical strength.

However, if the thickness of the front glass 23 is increased or curved, when the light reflected from the dichroic mirror 12 is transmitted through the front glass 23, the light path is changed by refraction and the light distribution is shifted.

Further, since the front glass 23 itself has a reflectance of around 8%, there is a problem that the central illuminance of the front irradiation surface is reduced by 5 to 15% due to the front glass 23.

Therefore, in the present invention, in order to enhance the strength of the front glass 23 without lowering the central illuminance of the front irradiation surface, the reinforcing films 32 are formed almost entirely on both the inner and outer surfaces of the front glass 23. ..

That is, flat soda lime glass is used as the front glass 23, and the SiO ₂ film which is the reinforcing film 32 is applied to both inner and outer surfaces thereof by dipping to a film thickness of about 0.1 μm, which is, for example, about 450 ° C. Bake at the temperature of about 10 minutes.

FIG. 5 shows the correlation between the breaking strength of the front glass 23 of this embodiment and the thickness of the SiO ₂ film of the reinforcing film 32. Reference numeral D in the drawing indicates this embodiment, and E indicates a conventional example. Are shown respectively.

The front glass 23 of this embodiment has a plate thickness of 1.5.
mm, and although the plate thickness of the conventional example is 2.5 mm, which is about 1 mm thinner, the breaking strength is equal to or more than that.

The reason is considered as follows.
That is, the surface of the front glass 23 is covered with the reinforcing film 3 of SiO ₂ film.
It is considered that the coating with 2 improves the strength because the dense and high-strength SiO ₂ layer fills minute cracks and scratches on the glass surface that cause the breakage of the glass.

However, if the thickness of the SiO ₂ film is thin, large cracks, scratches, etc. cannot be filled up, so the strengthening effect is low, and about 300 Å or more is required.

However, if the SiO ₂ film is too thick,
This time, it is considered that the defects of the SiO ₂ film itself become prominent, and this causes the destruction, so that the strength also decreases.

By the way, the front glass 23 is refracted according to Snell's law and a difference occurs in the optical path when the front glass 23 is not present. This optical path difference causes a shift in the light distribution and a decrease in the central illuminance as the thickness of the front glass 23 increases or the curvature of the curvature increases. Therefore, the flatter and thinner the front glass 23, the better.

The front glass 23 has a refractive index (n).
Is about 1.52, and the reflectance on both sides of the glass is about 8.0%. Therefore, the illuminance is reduced by the front glass 23.

On the other hand, in this embodiment, the refractive index n = 1.
The SiO ₂ film (n =
1.45) has an antireflection effect,
Moreover, since the plate thickness is thin, the transmittance is improved.

Further, since the reflectance of the glass plate generally increases depending on the incident angle, the front glass 23
The effect is large when the incident angle is large (for example, a wide-angle mirror).

FIG. 6 shows a comparison of the light distributions of the present embodiment and the conventional example when the dichroic mirrors 2 and 12 having the same beam angle and size are used. In the example, the light distribution is sharper than that of the conventional example shown by H, and the 1/2 beam angle is almost the same as that of the conventional example, but the central illuminance is improved by about 6%. Is shown.

FIG. 7 is a schematic side view of an embodiment of the second invention of the present application. In the figure, a halogen light bulb 41 with a dichroic mirror has a reflecting film 43 formed mainly on the inner surface of the tip of a spherical halogen light bulb 42. 1 is the same as that of the embodiment shown in FIG. 1 except for this point.
The parts common to the parts shown by are denoted by the same reference numerals, and the description of the overlapping parts is simplified or omitted.

Halogen bulb 41 with dichroic mirror
Has its dichroic mirror 12 with a diameter of, for example, about 5
It is formed by a spheroid of 0 mm, and the beam angle is set to about 20 ° by facets.

On the other hand, the halogen bulb 42 has a vertical coil-shaped filament 1 in the spherical portion 44a of the glass bulb 44.
8 built-in.

The halogen bulb 42 has a spherical portion 44a at least inside the conical surface connecting the center of the filament 18 and the front open end of the dichroic mirror 12.
A reflective film 43 having a spherical shape is formed on the inner surface of the tip of the. Since the temperature of the bulb 44 of the reflective film 43 rises to, for example, about 500 ° C., the high heat resistant Ni—Cr (60-40)
%) Electroless plating.

Therefore, for example, the light emitted at the center of the filament 18 is radially emitted from the center,
The dichroic mirror 12 and the reflection film 43 of the halogen bulb 41 are irradiated.

Visible light is reflected by the dichroic mirror 12 to form parallel rays, which are then radiated to the front irradiation surface.

On the other hand, the reflection film 43 reflects or scatters the incident light to the rear side of the filament 18 and returns a part of the heat rays to the filament 18 to raise the temperature to a high temperature to enhance the luminous efficiency. Other light is applied to the rear dichroic mirror 12 at various angles. Therefore, the light is reflected again by the dichroic mirror 12 and is irradiated onto the front irradiation surface.

Therefore, as shown by the broken line in FIG.
Since the direct light emitted from the halogen light bulb 42 without being reflected by the dichroic mirror 12 and shifted from the front irradiation surface can be focused on the center of the front irradiation surface, the conventional halogen lamp 51 with a dichroic mirror shown in FIG. In comparison with the above, the central illuminance of the front irradiation surface can be increased. The conventional halogen bulb 51 with a dichroic mirror has a reflection film 4
Since it is almost the same as the halogen light bulb 41 with a dichroic mirror of the present embodiment except that it does not have the structure shown in FIG.
The same parts as those of the above are denoted by the same reference numerals.

FIG. 9A shows the bidirectional light distribution characteristics of this embodiment, and FIG. 9B shows the same light distribution characteristics of the conventional halogen light bulb 51 with a dichroic mirror. The central illuminance is improved by, for example, about 8% as compared with the conventional example.

Further, in the present embodiment, as in the conventional example, a part of one leg 19b forms a side portion passing through the side of the filament 18, so that this side portion becomes a shadow and has a light distribution characteristic. There is a possibility that turbulence may occur, but the spherical reflective film 4
Due to the reflection or scattering effect of No. 3, the light distribution characteristics are improved as shown in FIG.

The reflective film 43 has a valve temperature of, for example, 4
Any material that can withstand about 100 to 500 ° C., C
It may be formed of r, Rh, Re, Ru, or the like, or an Inconel or Hastelloy alloy.

Further, the reflection film 43 does not have to be a metal mirror surface, but may be, for example, a diffuse total reflection film made of fine particles such as Al ₂ O ₃ or a visible light reflection multilayer interference filter.

Furthermore, an infrared reflection film may be formed on almost the entire spherical portion 44a of the bulb 44, and the reflection film 43 may be formed on a part of the film.
It is possible to increase the luminous efficiency by heating the filament 18 to a high temperature by reflecting the infrared ray from No. 8 back to the filament 18 by the infrared reflecting film and returning it.

[0064]

As described above, according to the first invention of the present application, since the front glass is provided with the interference filter for reducing the wavelength of 650 nm which adversely affects the color rendering property and the light around it, the color rendering property is enhanced. You can

Further, in the second invention of the present application, since the reflecting film is formed on the inner surface of the tip portion of the spherical bulb of the halogen bulb, the light emitted by the filament and reflected from the front irradiation surface is reflected. The film reflects or scatters to the dichroic mirror side, reflects again by the dichroic mirror, and irradiates the front irradiation surface, so that the light emitted deviating from the front irradiation surface can be condensed to the front irradiation surface. As a result, the illuminance of the front irradiation surface can be increased and the central luminous intensity thereof can be increased.

Further, according to the third invention of the present application, since the halogen light bulb with a dichroic mirror of the first or second invention has an infrared reflecting film formed on the inner peripheral surface of the halogen light bulb, the filament in the halogen light bulb is used. Of the emitted light, infrared rays of heat rays are reflected by the infrared reflecting film and return to the filament to heat it. Therefore,
The luminous efficiency of the filament can be increased.

[Brief description of drawings]

FIG. 1 is a partially cutaway vertical sectional view of an embodiment of a halogen light bulb with a dichroic mirror according to a first invention of the present application.

2A is a spectral distribution diagram of a conventional example, and FIG. 2B is a spectral distribution diagram of the embodiment shown in FIG.

FIG. 3 is a spectral distribution chart of the embodiment shown in FIG.

FIG. 4 is a partial vertical cross-sectional view of another embodiment of the present application.

5 is a graph showing the relationship between the film thickness and strength of the reinforcing film of the example shown in FIG.

6 is a graph showing the breaking strength of the front glass shown in FIG. 4 in comparison with a conventional example.

FIG. 7 is a schematic side view of an embodiment of the second invention of the present application.

8 is a schematic side view of a halogen light bulb with a dichroic mirror according to the embodiment shown in FIG.

9A is a light distribution characteristic diagram on the front irradiation surface of the embodiment shown in FIG. 7, and FIG. 9B is a light distribution characteristic diagram of the conventional example shown in FIG.

FIG. 10 is a partially cutaway vertical sectional view of a conventional halogen light bulb with a dichroic mirror.

11 is a graph showing the reflection characteristic of the dichroic mirror shown in FIG.

[Explanation of symbols]

11, 31, 41, 51 Halogen light bulb with dichroic mirror 12 Dichroic mirror 13, 42 Halogen light bulb 15 Visible light reflection infrared ray transmissive film 17,44 Valve 18 Filament 19a, 19b Pair of legs 20a, 20b Pair of molybdenum foil 21a, 21b Power reception Pin 23 Front glass 24 Interference filter 32 Reinforcement film 43 Reflection film

Claims (3)

[Claims] 1. A front open end of a dichroic mirror having a curved surface on which a visible-light-reflecting infrared-reflecting film that reflects visible light and transmits infrared rays is closed by a front glass, and a halogen bulb is incorporated therein. In a halogen bulb with a dichroic mirror, which has a vertical filament formed in a coil shape along the axis of the mirror in the halogen bulb, a wavelength of approximately 650 nm and the light around it are centered on the inner surface of the front glass. A halogen light bulb with a dichroic mirror, characterized in that it has an interference filter that reduces it. 2. The front open end of a dichroic mirror, which has a curved visible light reflection infrared reflection film that reflects visible light and transmits infrared light, is closed by a front glass, and a halogen bulb is built therein. In a spherical bulb of a halogen bulb, in a halogen bulb with a dichroic mirror having a vertical filament formed in a coil shape along the axial direction of the mirror, the center of the filament and the front open end of the mirror. A halogen light bulb with a dichroic mirror, characterized in that a light reflecting film is formed on at least the tip end surface of the bulb at a point farther from the connecting surface. 3. A halogen bulb has a bulb inner peripheral surface,
An infrared reflective film is formed, and the infrared reflective film is formed.
Or a halogen bulb with a dichroic mirror according to 2.