JP2001345066A - Orange-yellow colored metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent that human eye balls, which are exposed for a long time to lights of metal halide lamps at places with much traffic amount in an urban region and an express highway or the like, feel pale dazzling lights that are caused by numerous visible light components of short wavelength region. SOLUTION: The orange-yellow colored metal halide lamp is obtained wherein an optical type multi-layered film 8 is formed, that includes a layer in which high refractive index films and low refractive index films whose optical film thicknesses are specified from 30 to 200 nm are plurally laminated in alternation on a surface of light emitting tube 2 of the metal halide lamp 1 in which at least sodium iodide is enclosed or on a surface of light translucent member 3 surrounding the light emitting tube 2, and that has properties to cut blue short wavelength components in the visible light region and to make other long wavelength components pass. By this, the pale light which has visible light components of short wavelength region is cut to realize a new metal halide lamp which did not exist in the past and which emits lights of the orange- yellow color and which is friendly also to human eye balls, and problems are solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp used as a light source for a headlight of an automobile.

[0002]

2. Description of the Related Art Metal halide lamps have been significantly improved in luminous efficiency and color rendering by encapsulating a metal halide in addition to a rare gas and mercury in an arc tube. It is used as a light source for headlights and is receiving attention.

Generally, a metal halide lamp 90 of this kind is used.
For example, as shown in FIG. 12, an arc tube 91, a translucent member 92 surrounding the arc tube 91, and a socket 9 for mounting to a headlight (not shown) for an automobile.
3 and the like. At this time, the arc tube 91
Has a discharge section 9 as a space for causing discharge inside.
4 are provided, a pair of discharge electrodes 95 are held facing each other at an appropriate interval in the discharge portion 94, and a lead wire 96 is connected to each discharge electrode 95. In contrast, external power supply is possible.

The luminous tube 91 is covered with a substantially cylindrical light-transmitting member 92, so that the luminous tube 9 is formed.
1 is prevented from being kept at an appropriate temperature due to being cooled by the outside air or the like, thereby reducing the luminous efficiency.

The discharge portion 94 in the arc tube 91 is filled with a predetermined amount of a metal halide in addition to a rare gas such as xenon gas and mercury. When power is supplied to the discharge electrode 95 from the outside, Discharge is performed between the discharge electrodes 95, and the rare gas and the metal halide emit light to 4000
Lights with white light having a color temperature exceeding ° K, and provides superior color rendering properties as compared with filament lamps having a color temperature near 2800 ° K such as halogen bulbs. Utilizing the advantages of high output and high efficiency, it is used as a light source for automotive headlamps.

[0006]

However, such a conventional metal halide lamp 90 has excellent color rendering properties, but has a large amount of visible light components in a short wavelength range, and therefore has a high traffic volume such as an urban area or an expressway. When the human eyeball is exposed to this light for a long time, there is a problem that the human eyeball feels bluish and dazzling light due to a large amount of visible light components in a short wavelength range. Further, when traveling on snowy roads and the like, there is a problem that the light is pale and may become dazzling light for oncoming vehicles, and solving such a problem has been an issue.

[0007]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, at least a surface of an arc tube of a metal halide lamp in which sodium iodide is sealed or a light-transmitting material surrounding the arc tube. On the member surface,
The optical film thickness includes a layer in which a plurality of high-refractive-index films and low-refractive-index films each having a thickness set in the range of 30 to 200 nm are alternately laminated, and cuts a blue short-wavelength component in a visible light region. An object of the present invention is to solve the problem by providing an orange-yellow metal halide lamp characterized by forming an optical multilayer film having a characteristic of transmitting a long wavelength component.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 is a sectional view showing a first embodiment of a metal halide lamp 1 according to the present invention. As in the prior art, the metal halide lamp 1 has an arc tube 2 and a light-transmitting tube surrounding the arc tube 2. It is composed of a member 3 and a socket 4 for attaching to a headlight (not shown) for an automobile. At this time, a discharge portion 5 is provided in the arc tube 2 as a space for causing a discharge inside, and a pair of discharge electrodes 6 are held in the discharge portion 5 at appropriate intervals. At the same time, a lead wire 7 is connected to each of the discharge electrodes 6 so that external power can be supplied to the discharge electrodes 6.

The luminous tube 2 is covered with a substantially cylindrical light-transmitting member 3 to prevent the luminous tube 2 from being cooled by outside air or the like to maintain an appropriate temperature, thereby preventing a decrease in luminous efficiency. are doing. The operation up to this point is the same as that of the conventional example.

Here, in the present invention, a predetermined amount of scandium iodide and sodium iodide as a metal halide is sealed in the discharge portion 5 in the arc tube 2 in addition to a rare gas such as xenon gas and mercury. I have. As shown in FIG. 2, the emission spectrum of the metal halide lamp 1 in which scandium iodide and sodium iodide are sealed as such metal halides is shown as an orange-red component (600 nm to 600 nm).
750 nm).

In the present invention, an optical multilayer film 8 is formed on the entire surface of the translucent member 3 covering the arc tube 2.

FIG. 3 is a cross-sectional view showing a main part of a first embodiment of the optical multilayer film 8 according to the present invention. The high refractive index film 8a and the low refractive index film 8b are formed on the surface of the light transmitting member 3. Are formed by alternately laminating a plurality of layers each having an optical thickness of の of a target reflection wavelength (hereinafter referred to as a design wavelength) λ.
The light in the wavelength region centered on the design wavelength λ of the light emitted from the light source is reflected by light interference, and the light outside this wavelength region is transmitted.
Note that the optical film thickness is a value obtained by multiplying the physical film thickness of the layer by the refractive index. In the above film formation, the film is formed by an appropriate film formation method such as a vacuum evaporation method, a sputtering method, a dipping method, and an ion plating method.

Table 1 shows a specific film configuration of the optical multilayer film 8. The high refractive index film 8a and the low refractive index film 8b have a center wavelength λ of reflected light of 350 nm. The optical film thickness is set to λ / 4 = 87.5 nm. In the present embodiment, a Si film having a refractive index n _H = 3.3 is used as the high refractive index film 8a, and a low refractive index film 8b is used.
Used is a SiO ₂ film having a refractive index n _L = 1.46. The layer numbers in the table are numbered sequentially from the side closer to the surface of the translucent member 3, and the reference numerals in the figure correspond to those in FIG.

[Table 1]

Here, the optical film thickness of the high-refractive-index film 8a of the layer number 1 closest to the surface of the translucent member 3 and the optical film thickness of the high-refractive-index film 8a of layer number 7 which is the farthest uppermost layer are λ. / 8 ≒ 4
It is formed as 3.8 nm. This configuration is generally called an LW (long wavepass) type, whereby a portion on the long wavelength side of the transmittance characteristics of the entire film can be made flat and high transmittance characteristics.

Further, in this embodiment, the high refractive index film 8a
The Si film used as the material of the high-refractive-index film 8a has characteristics as a light-absorbing film (Abs) that absorbs short-wavelength light of 600 nm or less in general. In addition to the absorption of light on the short wavelength side by the above, the transmission of light on the short wavelength side of 600 nm or less can be suppressed by the reflection of light by the multilayer film of the Si film as the high refractive index film 8a and the low refractive index film 8b. it can.

In order to form the optical multilayer film 8 as described above, the cleaned translucent member 3 is first placed in an apparatus such as a vacuum evaporation apparatus, a plasma CVD apparatus, or a sputtering apparatus, and a high refractive index film is formed. Using Si and SiO ₂ as a low-refractive-index film as deposition sources, and using these devices to form films alternately while controlling the film thickness by a well-known vacuum deposition method, plasma CVD method, or sputtering method. be able to.

Hereinafter, a specific method for forming the optical multilayer film 8 of the present invention will be described with reference to an example using a vacuum evaporation method.

First, the cleaned translucent member 3 is fixed on a substrate in a vacuum vapor deposition apparatus, Si is placed on a crucible as a vapor deposition material, and the inside of the apparatus is evacuated to form a Si film on the translucent member 3. Is formed. Here, the substrate on which the translucent member 3 is fixed is configured to rotate around the central axis of the cylindrical shape of the translucent member 3, so that the entire surface of the translucent member 3 is evenly formed. The membrane can be used.

At this time, the conditions for forming the Si film are as follows: the substrate temperature (surface temperature of the translucent member 3) is 350 ° C .;
/ S, in oxygen-free atmosphere, as the ultimate vacuum degree of 1 × 10 ⁻⁴ Pa,
An Si film is formed on the translucent member 3. Then, this Si
For the light transmitting member 3 on which the film is formed, Si as a low refractive index film 8b similarly placed on a crucible in a vacuum evaporation apparatus is used.
O ₂ is deposited to form a film. At this time, the conditions for forming the SiO ₂ film are a substrate temperature of 350 ° C., a film forming speed of 10 ° / s, oxygen-free atmosphere, and an ultimate vacuum of 5 × 10 ⁻⁴ Pa. Thereafter, the Si film and the SiO ₂ film are alternately vapor-deposited and laminated under the same conditions.

The optical multilayer film 8 thus actually formed
FIG. 4 shows a transmittance characteristic of about 480 nm.
(Green light) wavelength gradually starts transmitting, yellow light,
The transmittance increases as the wavelength range of orange light and red light increases.

Here, as described above, in the metal halide lamp 1 of the present invention, scandium iodide and sodium iodide are used as the metal halide in the discharge portion 5 in the arc tube 2 in addition to the rare gas such as xenon gas and mercury. Is enclosed in a predetermined amount, the emission spectrum has a characteristic that the spectrum of the orange-red component (600 nm to 750 nm) is small as shown in FIG. 2, and the emission spectrum characteristic of the metal halide lamp 1 and the optical multilayer By utilizing the transmittance characteristics of the film 8, orange-yellow light emission can be obtained from the entire metal halide lamp 1.

FIG. 5 is a graph showing an emission spectrum of the metal halide lamp 1 in a state where the optical multilayer film 8 is formed in this manner. As compared with the emission spectrum of the metal halide lamp 1 before the formation in FIG. The optical multilayer film 8 has an orange-yellow emission characteristic in which transmission of light on the short wavelength side of 600 nm or less is suppressed.

At this time, as for the transmittance characteristics of the optical multilayer film 8 of the orange-yellow light emitting metal halide lamp, those having a characteristic of gradually starting to be transmitted from around 480 nm in the above-described embodiment are desirable. When it is desired to obtain a material having a characteristic of transmitting orange-yellow light, 400 nm to 55 nm
The transmission may be started within the range of 0 nm, the optical thickness of the Si film is 30 to 200 nm, and the optical thickness of the SiO ₂ is 50 to ₂ nm.
It has been confirmed from experiments that it can be obtained by appropriately setting within the range of 00 nm.

FIG. 6 is a sectional view showing a second embodiment of the optical multilayer film 8 according to the present invention, and Table 2 shows a specific film configuration thereof. As the film material, as in the first embodiment, Si having a refractive index n _H = 3.3, which is a light absorbing film (Abs), is used as the high refractive index film 8a, and the refractive index n _L = 1 as the low refractive index film 8b. .46 of SiO ₂ . Here, in this embodiment, the metal oxide film M is used as the seventh high-refractive-index film 8a on the outermost side farthest from the surface of the translucent member 3, and the metal oxide film M is n _H = 2.1 Ta ₂ O ₅ is used. This is because when the surface of the translucent member 3 of the first embodiment is heated to a high temperature of 300 ° C. or more, the Si film is oxidized and deteriorates, and the transmittance characteristic is changed. Therefore, a metal oxide film M without oxidation is formed and protected on the outermost seventh layer.

[Table 2]

The conditions for forming the Ta ₂ O ₅ film are as follows.
The surface temperature of the translucent member 3 is 350 ° C. (or room temperature to 500 ° C.), the film formation rate is 10 ° / s (or 1 to 10 ° / s), and the O ₂ partial pressure is 0.03 Pa in an atmosphere (0.01 to 0.
06 Pa), and a film is formed on the translucent member 3 at an ultimate vacuum of 5 × 10 ⁻⁴ Pa. The other film formation conditions are the same as in the first embodiment, and will not be described here.

The metal oxide film M serving as the high-refractive-index film 8a includes, in addition to the above-mentioned Ta ₂ O ₅ , TiO ₂ and ZrO ₂ .
₂ , Nb ₂ O ₅ , CeO ₂ , Al ₂ O ₃ or the like.

FIG. 7 shows the transmittance characteristics of the optical multilayer film 8 actually formed in this manner. As in the first embodiment, the optical multilayer film 8 gradually starts transmitting from a wavelength region of about 480 nm (green light). The transmittance increases in the wavelength region of yellow light, orange light, and red light. In addition, a film having a higher transmittance of orange light, particularly in the range of 600 to 700 nm, than the transmittance characteristics of the first embodiment was obtained. Similar characteristics can be obtained by appropriately setting the optical film thickness of the Si film within the range of 30 to 200 nm and Ta ₂ O ₅ and SiO ₂ within the range of 50 to 200 nm.

FIG. 8 is a sectional view showing a third embodiment of the optical multilayer film 8 according to the present invention, and Table 3 shows a specific film configuration thereof. As a film material, a light-absorbing film (Abs) is used as the high refractive index film 8a as in the first and second embodiments.
And a low-refractive-index film 8 with a refractive index n _H = 3.3.
As b, SiO ₂ having a refractive index n _L = 1.46 is used. Here, in this embodiment, the first high-refractive-index film 8 closest to the surface of the light-transmitting member 3 and the seventh outermost layer farthest to the farthest.
The metal oxide film M is used as a, and Ta ₂ O ₅ with n _H = 2.1 is used as the metal oxide film M. Thus, the effect of preventing the deterioration of the film is enhanced as compared with the second embodiment.

[Table 3]

The conditions for forming the Si film, the SiO ₂ film, and the Ta ₂ O ₅ film are the same as in the second embodiment, and will not be described here. Further, as the metal oxide film M as the high refractive index film 8a, in addition to Ta ₂ O ₅ , TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , CeO ₂ , A
It may be l ₂ O ₃ or the like.

FIG. 9 shows the transmittance characteristics of the optical multilayer film 8 actually formed in this manner. As in the first embodiment, the optical multilayer film 8 gradually starts transmitting from a wavelength region of about 480 nm (green light). The transmittance increases in the wavelength region of yellow light, orange light, and red light. Further, compared to the transmittance characteristics of the first and second embodiments, a film having a higher transmittance of orange light in the range of 600 to 700 nm could be obtained. The optical thickness of the Si film is 30 to 200 nm, and Ta ₂ O ₅
And SiO ₂ optical thickness similar characteristics can be obtained by appropriately set within a range of 50 to 200 nm.

FIG. 10 is a sectional view showing a fourth embodiment of the optical multilayer film 8 according to the present invention, and Table 4 shows a specific film configuration thereof. As the film material, as in the first embodiment, Si having a refractive index n _H = 3.3, which is a light absorbing film (Abs), is used as the high refractive index film 8a, and the refractive index n _L = 1 as the low refractive index film 8b. .46 of SiO ₂ . here,
In the present embodiment, the light absorbing film (Abs) of the high refractive index film 8a is only the fifth layer in the middle, and the remaining high refractive index film 8a uses the metal oxide film M. As the oxide film M, Ta ₂ O ₅ with n _H = 2.1 is used. In the present embodiment, the optical thickness is changed for each layer. The optical thickness of the first, second, eighth, and ninth layers is set to 150 nm, and the design wavelength λ = 150 × 4 = 6
Reflects light in the wavelength range centered on 00 nm,
The sixth, seventh, and seventh layers have an optical film thickness of 75 nm and are set to reflect light in a wavelength range centered on a design wavelength λ = 75 × 4 = 300 nm.

[Table 4]

The conditions for forming the Si film, the SiO ₂ film, and the Ta ₂ O ₅ film are the same as those in the above embodiments, and will not be described here. The metal oxide film M as the high refractive index film 8a is made of Ta ₂ O _5, as in the second embodiment.
TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , CeO ₂ ,
Al ₂ O ₃ or the like may be used.

FIG. 11 shows the transmittance characteristics of the optical multilayer film 8 actually formed in this manner. The transmittance as a whole is lower than that of the other embodiments and the light amount is slightly reduced. By setting the optical film thickness for each layer, the transmittance of light other than the wavelength region of orange-yellow light was suppressed, and a film having high transmittance in the orange-yellow wavelength region was obtained.

In the first to fourth embodiments,
Light absorption film (Abs) of high refractive index film 8a of optical multilayer film 8
Used a Si film, but instead of this Si film, a refractive index n
_{H x} = 2.5 Si _x O _y film (0 <x <1, 0 <y <1)
May be used.

[0036] At this time, _Si x _{O y} as the conditions for forming the film, the surface temperature of the light transmissive member 3 350 ° C. (room temperature to 500
C.), a film forming rate of 3 ° / s (1-10 ° / s may be used), an O ₂ partial pressure of 2 × 10 ⁻³ Pa atmosphere (3 × 10
^{−4 to} 5 × 10 ⁻² Pa), the ultimate vacuum degree 1 × 1
It is obtained by forming a film on the light transmitting member 3 as 0 ⁻⁴ Pa. The composition ratio of Si and O is x = 0 to 1,
When y = 1 to 0, and the oxygen partial pressure is increased, the ratio y of O increases, and the SiO ² film is formed at a partial pressure of O ₂ of about 1 × 10 ⁻² Pa.

Since the thus formed Si _x O _y film has an excellent absorption characteristic for short wavelength light of 600 nm or less as compared with the Si film, if this film is used as a light absorbing film (Abs), the light on the short wavelength side is used. , The optical multilayer film 8 having a high transmittance in the orange-yellow wavelength region can be obtained.

Further, as the light-absorbing film having a high refractive index film 8a of the optical multilayer film 8 (Abs), Si film, _Si x _{O y} amorphous silicon besides film (hereinafter referred to as a-Si) film or polysilicon A film (hereinafter, referred to as poly-Si) may be used.

At this time, the conditions for forming the a-Si film are as follows: the surface temperature of the translucent member 3 is 350 ° C. (or room temperature to 500 ° C.), and the film forming speed is 3 ° / s (1 to 10 ° / s). ,
An a-Si film is formed on the light transmitting member 3 in a hydrogen atmosphere at a pressure of 3 × 10 ⁻⁴ to 1 × 10 ⁻² Pa and a degree of ultimate vacuum of 1 × 10 ⁻⁴ Pa. Further, the poly-si film is formed by forming an a-Si film formed under the same conditions by setting the surface temperature of the light transmitting member 3 to 700.
It is obtained by placing it in the atmosphere for 4 hours or more at a temperature raised to ° C.

The a-Si film or poly-Si film, Si film or _Si x _O the absorption characteristics of light 600nm or less wavelength than the _y film is better, the light-absorbing layer of this film (Ab
When used as s), the optical multilayer film 8 having high transmittance in the orange-yellow wavelength region can be obtained while suppressing the transmittance of light on the short wavelength side.

In each of the above embodiments, the light absorbing film is used.
(Abs), Si film, Si_xO _yFilm, a-Si
Although a film and a poly-Si film were used, the present invention is not limited to this.
However, as another light absorbing film, a wavelength of 600 nm or less
Any film having a characteristic of absorbing light may be used.
ZnO film, In₂O₃, Fe₂O₃Metal oxide film
These films may be formed under the following conditions, respectively.
This results in a light absorbing film having the above characteristics.

First, the ITO film as the light absorbing film was formed at a substrate temperature of 200 ° C. (within a range from ordinary temperature to 500 ° C.) and a film forming rate of 5 ° C.
Å / s (within the range of 1Å10 Å / s), under oxygen-free conditions, and at a final vacuum degree of 1 × 10 ⁻³ Pa. The ZnO film and the In ₂ O ₃ film are obtained under the same conditions. Obtainable. For the Fe ₂ O ₃ film, the substrate temperature was 200 ° C. (within the range of ordinary temperature to 500 ° C.), and the film formation rate was 5 °.
/ S (within the range of 1 to 10 ° / s), oxygen-free to 0.02P
Each film is obtained by forming a film in an atmosphere a under a condition of an ultimate vacuum degree of 1 × 10 ⁻³ Pa.

In each of the embodiments of the optical multilayer film 8 of the present invention, the metal oxide film M used as the high refractive index film 8a is used.
Of Ta ₂ O ₅ as the material of the substrate and Si as the low refractive index film
Although O ₂ is used, other materials such as metal oxides may be used, and almost the same characteristics can be obtained. To give a specific example, TiO ₂ , ZrO ₂ , Z
_{nS, Zi 3 N 4, Nb} 2 O 5, CeO 2, Al 2 O 3
There are MgF ₂ , AlF _{6 and the} like as the low refractive index film.

In the present embodiment, the optical multilayer film 8 has been described as being formed on the surface of the translucent member 3 surrounding the arc tube 2, but may be formed directly on the surface of the arc tube 2. good.

Further, although the case where the metal halide lamp 1 is filled with scandium iodide and sodium iodide is described above, the present invention is not limited to this, and at least sodium iodide is filled. A combination of sodium iodide and other rare earth iodides such as dysprosium iodide or a combination of alkali metal iodides such as thallium iodide and indium iodide may be used.

[0046]

As described above, according to the present invention, an optical film thickness of 30 to 200 nm is formed on at least the surface of the arc tube of the metal halide lamp in which sodium iodide is sealed or the surface of the light-transmitting member surrounding the arc tube. The high refractive index film and the low refractive index film set in the range include a layer in which a plurality of layers are alternately laminated, cut a blue short wavelength component in a visible light region, and transmit other long wavelength components. By using an orange-yellow metal halide lamp having an optical multilayer film having characteristics, at least a predetermined amount of sodium iodide is sealed in the arc tube, the emission spectrum of the orange-red component (600 nm to 750 nm) is low. It has a small characteristic, and cuts the emission spectrum characteristic and the transmittance characteristic of the optical multilayer film, that is, the blue short wavelength component, and removes the other long wavelength component. In addition to the advantages inherent in conventional metal halide lamps, such as small size, high output, and high efficiency, by utilizing the characteristics that pass through, it also cuts the pale white light, which is the visible light component in the short wavelength range, and is orange that is gentle on the human eyeball. This realizes a novel metal halide lamp that emits yellow light.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a metal halide lamp according to the present invention.

FIG. 2 is a graph showing an emission spectrum of a metal halide lamp according to the present invention before an optical multilayer film is formed.

FIG. 3 is a sectional view showing a first embodiment of the optical multilayer film according to the present invention.

FIG. 4 is a graph showing transmittance characteristics of the first embodiment of the optical multilayer film according to the present invention.

FIG. 5 is a graph showing an emission spectrum of the metal halide lamp according to the present invention after an optical multilayer film is formed.

FIG. 6 is a sectional view showing a second embodiment of the optical multilayer film according to the present invention.

FIG. 7 is a graph showing transmittance characteristics of a second embodiment of the optical multilayer film according to the present invention.

FIG. 8 is a sectional view showing a third embodiment of the optical multilayer film according to the present invention.

FIG. 9 is a graph showing transmittance characteristics of a third embodiment of the optical multilayer film according to the present invention.

FIG. 10 is a sectional view showing a fourth embodiment of the optical multilayer film according to the present invention.

FIG. 11 is a graph showing transmittance characteristics of a fourth embodiment of the optical multilayer film according to the present invention.

FIG. 12 is a sectional view showing a metal halide lamp in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal halide lamp 2 ... Arc tube 3 ... Translucent member 4 ... Socket 5 ... Discharge part 6 ... Discharge electrode 7 ... Lead wire 8 ... Optical multilayer film 8a ... High refractive index film (Abs) Light absorbing film (M) Metal oxide film 8b Low refractive index film

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Hiramoto 1-3-1 Edanishi, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Stanley Electric Co., Ltd. F-term (reference) 5C043 AA02 CC03 CD05 DD27 EA14 EA15 EB11 EC13

Claims (4)

[Claims] An optical film having a thickness of 30 to 200 nm is formed on at least the surface of an arc tube of a metal halide lamp in which sodium iodide is sealed or on the surface of a light-transmitting member surrounding the arc tube.
The high refractive index film and the low refractive index film set in the range include a layer in which a plurality of layers are alternately laminated, cut a blue short wavelength component in a visible light region, and transmit other long wavelength components. An orange-yellow metal halide lamp having an optical multilayer film having characteristics. 2. The method according to claim 1, wherein at least one of the high refractive index films of the optical multilayer film is formed of a light absorbing film having a characteristic of absorbing light having a wavelength of 600 nm or less. Orange-yellow metal halide lamp. Wherein the light absorbing layer of the silicon film, Si _X O
3. The orange-yellow metal halide lamp according to claim 2, wherein a _y (0 <x <1, 0 <y <1) film, an amorphous silicon film or a polysilicon film is used. 4. The orange according to claim 1, wherein at least the outermost layer of the optical multilayer film farthest from the arc tube or the surface of the translucent member is formed of a metal oxide film. Yellow metal halide lamp.