JPH05325900A - Metal halide lamp with inclining function film and its luminaire - Google Patents

Abstract

PURPOSE:To provide a metal halide lamp and its luminous fixture in which the color temperature is reduced, and the color temperature is not changed even through the angle observing the luminous center of the lamp is changed, and a specific color temperature is maintained in any radiating direction. CONSTITUTION:Heat insulating membranes 4 and 5 are provided on the periphery of the electrode of a metal halide lamp luminous tube 1 in which electrodes 2 and 3 are provided on body ends, and mercury, a rare gas, and a metal halide are sealed. A sleeve 6 made of a quartz glass is arranged around the luminous tube 1; and an inclining function membrane 7 which consists of a thin film of a titanium oxide and a silicon dioxide, and the composition ratio is converted continuously in the membrane thickness direction; is provided to the surface of the above sleeve 6.

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 whose color temperature is corrected and a lighting fixture containing the metal halide lamp.

[0002]

2. Description of the Related Art Metal halide lamps have been widely used for indoor lighting and the like because of their excellent color rendering properties and high luminous efficiency. However,
Since the metal halide lamp has a color temperature of 4000 K or higher and the color temperature is too high for applications such as indoor lighting, some attempts have been made to reduce the color temperature.

One of the attempts to reduce the color temperature is to improve the lamp itself, such as changing the type of the filling material (in particular, metal halide) in the arc tube. In addition, the arc tube of a metal halide lamp and the arc tube are also included. A cylindrical glass tube (hereinafter abbreviated as "sleeve") surrounding the arc tube disposed in the vicinity of the light emitting tube, an outer bulb, or an optical interference film formed on the surface of a front glass of a lighting fixture that houses a metal halide lamp. It has been proposed to use it and has been partially put into practical use.

Since the light interference film can function as a color temperature conversion filter if the spectral transmission characteristics are appropriately designed, it is possible to correct the color temperature of the metal halide lamp to bring it closer to a desired color temperature. However, since a single layer of the optical interference film has a small effect of reducing the color temperature, a multilayered film structure of two or more layers is usually used.

In the conventional optical interference multilayer film, each layer is made of a transparent dielectric material, a metal, a transparent conductive material or the like, and one of these materials or a mixture of two or more materials. In each of the individual layers, there is no bias in terms of material composition and they are substantially uniform. Further, there is an interface between layers, and each layer is independent.

[0006]

By the way, in the case of the conventional optical interference multilayer film, its spectral transmittance changes depending on the incident angle of light on the film surface, and the incident angle becomes large, and the spectral transmittance curve is Is characterized by moving to the short wavelength side.

Therefore, when the conventional light interference multilayer film is used as a color temperature conversion filter, the color temperature of the lamp changes depending on the incident angle of the light from the light emission center with respect to the light interference multilayer film. There is a drawback that the color temperature differs depending on the type, and the color appearance of the object illuminated by the lamp is not uniform in all directions.

This tendency becomes more remarkable as the number of layers of the optical interference multilayer film increases, and if the number of layers is decreased, it is alleviated, but it has not been a fundamental solution. Further, the above-mentioned drawbacks are relatively slight when the formation site of the light interference multilayer film is close to the emission center such as the surface of the arc tube. The interference multi-layered film becomes more prominent as the formation position of the interference multi-layered film moves away from the emission center and the range of possible incident angles of light on the film surface expands.

The present invention has been made in order to solve the above problems in a conventional metal halide lamp having a light interference multilayer film and its luminaire. The color temperature is lowered and the emission center of the lamp is reduced. It is an object of the present invention to provide a metal halide lamp and a lighting device for the metal halide lamp, in which the color temperature value does not change even if the angle of view changes, and the color temperature is constant in any irradiation direction.

[0010]

In order to solve the above problems, the present invention uses a functionally graded film instead of the conventional optical interference multilayer film.

The functionally graded film is a thin film in which the composition ratio of substances constituting the film changes continuously in the film thickness direction. Unlike the conventional optical interference multilayer film, this thin film has no difference in that there is no interface separating the layers, and the film constituent substances are mixed to form one layer as a whole. By using the same film interference substance as the optical interference multilayer film, it is possible to provide a function similar to that of the conventional optical interference multilayer film.

This functionally graded film can be formed by a known film forming method such as a vacuum vapor deposition method, a sputtering method or a CVD method. The film formation principle is, for example, substance A and substance B.
The film formation rate of the substance A is gradually increased with time, and the film formation rate of the substance B is gradually decreased with time, for example. If the film forming conditions are set to, and both are simultaneously deposited on the surface of the substrate, the composition ratio of the substance B becomes higher as it gets closer to the substrate, and conversely the composition ratio of the substance A becomes higher as it gets farther from the substrate. A functionally gradient film having a distribution is formed.

[0013]

The function of the functionally graded film is that the change in the spectral transmission characteristic (spectral reflection characteristic) due to the change in the incident angle of light with respect to the film surface is small. Therefore, when the functionally gradient film is arranged so as to surround the light source, in addition to the color temperature of the light source after passing through the functionally gradient film being reduced by a predetermined value due to the function of the functionally gradient film as an optical interference film, It is maintained almost constant in any irradiation direction of light.

Therefore, the above-mentioned functionally gradient film is formed on at least one surface of the sleeve in the case of a metal halide lamp having the arc tube of the metal halide lamp, the outer bulb of the lamp, and the sleeve, or on the surface of the front glass of the luminaire. By doing so, not only the color temperature of the metal halide lamp is lowered by a predetermined value as compared with the case without the film, but the color temperature value hardly changes even if the angle at which the emission center of the lamp is viewed changes. It is possible to realize a low color temperature which is almost constant in the irradiation direction.

[0015]

First, prior to the description of the embodiments, the function and effect of the functionally gradient film according to the present invention in theoretical calculation will be described in comparison with the function of a conventional optical interference multilayer film. Therefore, as an example of the translucent member surrounding the arc tube of the metal halide lamp, for example, an optical interference multilayer film formed on the outer surface of the sleeve or the functionally gradient film according to the present invention is used to convert the color temperature of the metal halide lamp. Think about what to do.

FIG. 1 is a schematic cross-sectional view in the axial direction around the arc tube of a metal halide lamp provided with a functionally graded film according to each invention or a conventional light interference multilayer film, and the other parts of the metal halide lamp are not shown. I am doing it. In the figure, 1 is an arc tube, 2 and 3 are electrodes, 4 and 5 are heat insulating films,
6 is a sleeve arranged around the arc tube 1, and 7 is a functionally graded film or an optical interference multilayer film provided on the surface of the sleeve 6. Further, l _T and l _S are the total lengths of the arc tube 1 and the sleeve 6, respectively, D _T and D _S are the outer diameters of the arc tube 1 and the sleeve 6, respectively, and d is the distance between the electrodes 2 and 3. 150
An example of dimensions for a W metal halide lamp is
l _T = l _S = 56 mm, D _T = 15 mm, D _S = 26 mm, d = 20 mm
Is. Further, the gap between the two heat insulating films 4 and 5 is usually 10 mm or more, although a distance of at least half the distance between the electrodes is usually secured.

In FIG. 1, reference numeral 8 represents the center point of the arc tube 1. Further, 9 is the path of the light (incident angle 0 °) emitted from the central point 8 and perpendicularly incident on the film surface of the functionally graded film or the optical interference multilayer film 7, and 10 is also emitted from the central point 8. The path of light having the maximum incident angle θ ₁ that is not blocked by the heat insulating film 4 applied to the surface of the arc tube around the one electrode 2 is shown. Further, 11 indicates the path of light emitted from the surface of the electrode 3 and having the maximum incident angle θ ₂ which is not blocked by the heat insulating film 4. 150 W with said dimensions
In the case of a metal halide lamp, θ _{1 is} approximately 36 ° and θ _{2 is} approximately 63 °.

From the above, the center point of the arc tube (or the middle point between the electrodes) that mainly contributes to the lamp characteristics 8
The angle of incidence of the light from the film on the film surface is almost 0 ° near the center of the sleeve 6, but the angle of incidence increases as the distance from the center of the sleeve 6 increases, and the maximum angle of incidence not blocked by the heat retaining film 4 or 5. It can be seen that the incident angle exceeds 30 ° at the position where (θ ₁ ) is reached. It can also be understood that the incident angle can be more than 60 ° in the case of light emitted from the electrode that contributes little to the lamp characteristics and its surroundings.

In the case of metal halide lamps having other lamp powers, as in the case of 150 W described above, the ratio of the arc tube overall length to the arc tube outer diameter l _T / D _T and the sleeve outer diameter to the sleeve outer diameter l _{Most of S} / D _S respectively
The above conclusions also apply to metal halide lamps with other lamp powers (other arc tube dimensions), since they are in the range 3.5-4.0 and 1.7-2.3.

A seven-layer film and a two-layer film are taken as examples of the conventional optical interference multilayer film, and the comparison between the optical interference multilayer film and the functionally gradient film according to the present invention will be described below. First, for example, consider a seven-layer film having a spectral transmittance curve shown by the solid line in FIG. 2 when the incident angle is 0 °. This is often used as a bandpass filter for lowering the color temperature of a lamp. For example, titanium oxide (TiO ₂ ) (refractive index 2.1 to ₂ .
3) and a thin layer of both silicon dioxide (SiO ₂ ) (refractive index 1.45 to 1.46), the first layer is a TiO ₂ layer and the second layer is a SiO 2 layer.
_{The second} layer, ..., And the seventh layer can be constituted by alternately laminating like a TiO ₂ layer. According to theoretical calculation, the spectral transmittance curve of the seven-layer film moves to the shorter wavelength side as a whole with the increase of the incident angle, and reaches the position shown by the broken line in FIG. 2 at the incident angle of 60 °.

The color temperature of a metal halide lamp without a film, that is, the color temperature of the arc tube 1 is, for example, 4700.
When it is K, the color temperature of the light transmitted through the 7-layer film is 43 from the theoretical calculation when the incident angle is 0 °, as shown in Table 1.
It becomes 42K, and brings about a decrease in color temperature of 300K or more. However, at an incident angle of 30 °, the degree of decrease in color temperature decreases as the incident angle increases to 4528K, and the incident angle becomes 45 °.
In the case of, the color temperature is hardly decreased, and when the incident angle is further increased, for example, the color temperature is increased, such as 4803K at the incident angle of 60 °.

[0022]

[Table 1]

Next, for example, when the incident angle is 0 °, as shown in FIG.
Consider a two-layer film having a spectral transmittance curve indicated by the solid line.
The two-layer film also uses, for example, a TiO ₂ thin layer and a SiO ₂ thin layer,
The layer may be a TiO ₂ layer and the second layer may be a SiO ₂ layer. According to the theoretical calculation, in the case of the two-layer film as well, the tendency of the spectral transmittance curve to shift to the short wavelength side with the increase of the incident angle is the same as in the case of the seven-layer film, and the incident angle is 60 °. Then, the spectral transmittance curve shown by the broken line in FIG. 3 is obtained.
Also in the case of the two-layer film, the degree of decrease in the color temperature of the transmitted light becomes smaller as the incident angle increases as shown in Table 1, and is improved as compared with the above seven-layer film, but the incident angle is improved. Is 45 °
If it exceeds, the color temperature of the lamp without a film is almost the same as the color temperature.

On the other hand, when the functionally gradient film according to the present invention is used, by optimizing the film design, it is possible to form a film in which the color temperature of the transmitted light changes little with the change of the incident angle. .. Here, for example, a high refractive index material such as TiO ₂
For example, consider a functionally graded film made of a low refractive index material such as SiO ₂ . Then, in order to assume a functionally graded film having the same effect as the color temperature reduction at the incident angle of 0 ° of the optical interference multilayer film (7-layer film and 2-layer film) described above, the refractive index of 2.1 to 2 is used. .3
₂ of TiO ₂ having a refractive index and SiO ₂ having a refractive index of 1.45 to 1.46
When a graph is drawn with the substance as a constituent element and the composition percentage of TiO ₂ as the ordinate and the distance from the substrate surface in the film thickness direction as the abscissa, as shown in FIG. 4, a TiO ₂ composition percentage curve is obtained. It is assumed that the functionally gradient film has an asymmetric V shape (thick solid line in the figure). That is, the film thickness of the functionally gradient film is set to 168 nm, and the film thickness of 14
The composition percentage of TiO ₂ decreases linearly from 100% to 0% up to 0 nm, and the composition percentage of TiO ₂ extends from the 140 nm film thickness to the surface of the functionally gradient film (168 nm). Is 0
Assuming a linear increase from% to 100%. Of course, if attention is paid to the composition percentage of SiO ₂ , the relationship of increase and decrease is opposite to the case of TiO ₂ .

Further, for convenience of the simulation calculation, the functionally graded film is divided into some in the film thickness direction of the functionally graded film. That is, the composition percentage of TiO ₂ is 0%.
With the point (bottom of the V-shaped valley) as the boundary point, the front and rear sides are divided into 10 equal parts for the film thickness, and for each of the subdivided films, the refractive index is from the substrate surface to the boundary point. A total of 20 (including the same value) refractive index values are assigned so that the values decrease linearly and increase linearly after the boundary point. In this way, the functionally graded film is replaced with a 20-layer film that is asymmetrically divided into 20 layers assuming an interlayer interface for convenience. Table 2 shows the film constitution of the 20-layer film when the substrate material is quartz glass, the refractive index of TiO ₂ is 2.30, and the refractive index of the SiO ₂ layer is 1.46. If the number of divisions in the film thickness direction is increased infinitely, it is possible to approach the ideal film structure of the functionally gradient film.

[0026]

[Table 2]

The asymmetric 20-division functionally gradient film having the film structure shown in Table 2 is theoretically calculated as shown in FIG.
When the incident angle is 0 °, the spectral transmittance curve becomes like a solid line,
Also, when the incident angle is 60 °, it becomes like a broken line. The tendency of the spectral transmittance curve to shift to the short wavelength side with the increase of the incident angle is the same as in the case of the conventional 7-layer and 2-layer optical interference multilayer films.

Asymmetric 20 having such a spectral transmission characteristic
For the split functionally graded film, the color temperature of the light emitted from the same metal halide lamp as that of the 7-layer film and the 2-layer film after passing through the film was calculated, and as shown in Table 1, the color temperature with the increase of the incident angle was calculated. The degree of increase is considerably smaller than that of the 7-layer film and the 2-layer film, and the color temperature decrease of about 500 K at an incident angle of 0 ° is maintained at about 400 K even at an incident angle of 60 °. ..

Next, the practical function and effect of the functionally graded film in a specific embodiment of the present invention will be described in comparison with a conventional example. First, an arc tube containing at least mercury, argon, dysprosium iodide, thallium iodide, and cesium iodide, a quartz glass sleeve surrounding the arc tube and having no film formed on its surface, the arc tube and the arc tube. One metal halide lamp having an outer bulb containing a sleeve was prepared. The above arc tube has a total length of 56m, similar to that shown in FIG.
m, outer diameter 15 mm, wall thickness 1.2 mm, distance between electrodes 20 mm, and the sleeve has a total length of 56 mm, outer diameter 26 mm, wall thickness 2.5 mm. The arc tube is arranged such that its central axis coincides with the central axis of the sleeve and does not protrude from the sleeve in the axial direction. In addition, when the input voltage is adjusted so that the lamp power is constant at 150 W, the metal halide lamp has a lamp voltage of 90 V and a lamp current of
It was 1.9A. At this time, the color temperature is 4880K, the general color rendering index R _a is 94, then the light emitting spectral distribution was as indicated by a broken line in FIG. 6.

Next, three quartz glass sleeves having the same material, size, and shape as the above-mentioned sleeves were prepared, and the seven-layer optical interference films (conventional example 1) and 2 were formed on the outer surfaces of the respective sleeves.
The layered light interference film (conventional example 2) and the functionally gradient film according to the present invention (example 1) were formed to prepare three types of film-coated sleeves. The creation method is as follows.

The 7-layer optical interference film and the 2-layer optical interference film are designed to have the same film configurations as those shown in the explanation of the theoretical calculation, and the vacuum vapor deposition method, the sputtering method, the CVD method, the sol-gel are used. It was formed by laminating a TiO ₂ thin layer and a SiO ₂ thin layer by using a known method such as a method (immersion firing method). Further, it was confirmed by the measurement of the spectral transmittance that the spectral transmission characteristics of the 7-layer optical interference film and the 2-layer optical interference film were in good agreement with the characteristics shown in FIGS. 2 and 3, respectively.

The functionally graded film according to the present invention is formed by the vacuum deposition method,
It was formed using a known method such as a sputtering method or a CVD method. For example, a film was formed by the following procedure using a vacuum vapor deposition method. First, FIG. 7 shows a system configuration of a film forming apparatus used for forming the functionally gradient film on the sleeve of the first embodiment. Titanium oxide (TiO ₂ ) solid and silicon dioxide (SiO ₂ ) solid were used as raw materials for the film material. A sleeve (sample sleeve) 23 on which the functionally gradient film is to be formed is supported by a holder 24 in the vapor deposition chamber 20 and is kept at a predetermined temperature by a heater 22. For film formation, the two shutters 27 are opened simultaneously, the TiO ₂ raw material 28 and the SiO ₂ raw material 29 are heated at the same time, and vapor deposition is performed while independently controlling the evaporation rates of both raw materials. At the time of vapor deposition, the sample sleeve 23 revolves around the central axis of the vapor deposition chamber 20 by rotation of the holder 24 itself, and also rotates about the central axis of each sleeve individually by a rotation mechanism (not shown). .. The TiO ₂ raw material 28 is an electron gun 30 and an electron gun power source.
The desired TiO ₂ is heated by the crystal oscillator sensor 26 and the crystal type film thickness meter 34 calibrated for the TiO ₂ film.
The evaporation rate is controlled so that the film formation rate is obtained. On the other hand, the SiO ₂ raw material 29 includes an electron gun 31 and an electron gun power source 33.
It is heated by, so that a desired SiO ₂ deposition rate by a quartz oscillator sensor 26 and the crystal film thickness meter 35 calibrated for the SiO ₂ film, the evaporation rate is controlled.
The end point of the vapor deposition is performed by performing vapor deposition on the monitor glass 25 at the same time as the sample sleeve 23, and measuring the measured value of the light transmittance of the monitor glass by converting it to the film thickness by the optical film thickness meter 21.

In the film-forming apparatus constructed as described above, the evaporation operation is actually performed by the system control system 36 by automatically controlling the entire system. It is necessary to set conditions in advance. First, the optical film thickness meter 21 is set with conditions for converting the light transmittance to the film thickness in the case of a functionally gradient film according to the intended film configuration. Next, for the control of the evaporation rate of the raw material, the TiO ₂ film formation rate is 14.0 nm / min every 1 minute until the optical film thickness meter 21 detects the film thickness of 140 nm.
min, 12.4nm / min, 10.9nm / min, 9.3nm / min, ...
・, And 0.0 nm / min, gradually decreasing in 10 steps, while the SiO ₂ film forming rate is 0.0 nm / min, 1.6 nm / min
, 3.1nm / min, 4.7nm / min, ..., 14.0nm / min
In this way, set the condition so that it gradually increases in 10 steps,
In addition, subsequently, until the optical film thickness meter 21 detects the film thickness of 168 nm (end point), the TiO ₂ film formation rate becomes 0.
0nm / min, 1.6nm / min, 3.1nm / min, 4.7nm / mi
n, ..., 14.0 nm / min, gradually increasing in 10 steps, while the SiO ₂ film forming rate is 14.0 nm / min, 12.4 nm / mi
n, 10.9nm / min, 9.3nm / min, ..., 0.0nm / min
In this way, the condition is set so that it gradually decreases in 10 steps. In this condition setting, it takes 12 minutes in total for one vapor deposition operation of the functionally gradient film.

When the spectral transmittance of the sleeve formed with the functionally gradient film was measured under the above conditions, the spectral transmittance curve was as shown in FIG. 8, which is in good agreement with the theoretical calculated value of FIG. It was confirmed. In FIG. 8, the solid line is for an incident angle of 0 ° and the broken line is for an incident angle of 60 °. Such agreement between the theoretical value and the measured value is the same as one vapor deposition process under the above condition setting is subdivided into 20 small processes, and the film structure of the functionally gradient film formed is In fact, it is considered that the film has the same film structure as the asymmetric 20-division functionally-graded film described in the explanation of the theoretical calculation.

Next, the measurement of the color temperature of the metal halide lamp equipped with the film-coated sleeve will be described. FIG. 9 shows a schematic longitudinal sectional view of the arc tube 1 in the axial direction and an outline of a method for measuring color temperature. Although the outer bulb and other parts are omitted in FIG. 9, in the actual measurement, the arc tube 1 and the sleeve 6 were housed in the outer bulb, and the measurement was performed with a normal lamp configuration. Therefore, in the case of measurement, the above-mentioned 3
For each of the types of film-coated sleeves, after each measurement, the film-coated sleeve was fixed in such a position that the central axis of the film-coated sleeve coincided with the central axis of the arc tube 1 and the arc tube 1 did not protrude from the sleeve 6. A lamp was completed by attaching an outer bulb and the like to and measured, and then the outer bulb of this lamp was destroyed and replaced with the next film-coated sleeve. The arc tube 1 is the same as that described above for any film-coated sleeve.

The color temperature was measured by turning on the lamp with a lamp power of 150 W and at two incident angles of 0 ° and 30 °. As shown in FIG. 9, the spectrophotometer light receiving unit 15 is arranged at a position where the center point 8 of the arc tube 1 is always expected. The angle when the straight line of the light receiving portion 15 looking into the center point 8 coincides with the line passing through the center point 8 and orthogonal to the center axis of the sleeve 6 (arc tube 1) is taken as the reference of the incident angle, and this is set to 0 °. .. For incident angles over 30 °, the spectrophotometer receiver
It was not measured due to the arrangement of 15. In FIG. 9, 9 and 12 represent the paths of light having incident angles of 0 ° and 30 °, respectively. Table 3 shows the measurement results of the color temperature.

[0037]

[Table 3]

As shown in Table 3, in the case of the seven-layer optical interference film (conventional example 1), the degree of color temperature decrease at an incident angle of 0 ° is the smallest among the three kinds of films, and the incidence is small. The degree of increase of the color temperature with the increase of the angle was the largest, and the color temperature at the incident angle of 30 ° was increased by about 250 K as compared with the case of 0 °. On the other hand, in the case of the two-layer optical interference film (conventional example 2), the effect of reducing the number of layers is exhibited, and the increase in color temperature due to the increase of the incident angle is suppressed to be smaller than that in the case of conventional example 1 described above. The increase was only about 200K. On the other hand, in the case of the functionally gradient film (Example 1), in addition to the decrease in the color temperature of 500 K or more at the incident angle of 0 °, the incident angle increased from 0 ° to 30 °. The increase in color temperature was suppressed to less than 100K.

The emission spectral distribution of the transmitted light of the functionally gradient film had the distribution shown by the solid line in FIG. 6 when the incident angle on the film surface was 0 °. In comparison with the distribution of the broken line in the case without a film in FIG. 6, the light after passing through the film shows that the light on the short wavelength side (38
The emission component from 0 to 500 nm) decreases and the long wavelength side (550 to 70 nm)
It can be seen that the emission component at 0 nm) is increasing.

The above-mentioned actual measurement results fully support the above-mentioned theoretical calculation results, and clearly show the excellent color temperature conversion action of the functionally graded film which is not affected by the change in the incident angle of light.

Next, a second embodiment will be described. In this embodiment, a functionally graded film is formed on the front glass of a lighting fixture that houses a metal halide lamp. Figure 10
A schematic vertical sectional view of the luminaire and an outline of a method for measuring color temperature are shown in FIG. In the figure, 17 is a mirror and 18 is a front glass with film. The front glass with film 18 is attached so that the surface on which the functionally gradient film 19 is formed faces the outside of the lighting fixture.
The central axis of the metal halide lamp 16 is substantially parallel to the front glass 18, and the central axis of the arc tube 1 is fixed by adjusting the respective arrangements so as to substantially coincide with the central axis of the metal halide lamp 16. Metal halide lamp 16
The type of the filling material in the arc tube is the same as in the conventional example 2 and the example 1, and the size of the arc tube 1 is almost the same as in the conventional example 2 and the example 1. Further, in the metal halide lamp 16, there is no portion where a film is formed on the surface of the arc tube 1 except that a heat insulating film is provided on the end surface thereof. The lamp characteristics when the front glass without any film is attached are as follows: when the lamp power is 150 W and the metal halide lamp 16 is turned on, the lamp voltage is 102 V,
The lamp current is 1.7A, the color temperature is 4370K, the general color rendering index R _a was 96.

Next, in order to confirm the effect of the luminaire thus constructed, the conventional two-layer optical interference film (conventional example 3) and the functionally gradient film of the present invention (example 2) are both used. Replace the front glass formed on one side with the same lighting fixture that houses the same metal halide lamp and install it,
The metal halide lamp was turned on, the color temperature of the light transmitted through the front glass was measured, and the results were compared with each other. The two-layer optical interference film and the functionally gradient film were formed on the front glass surface by the same methods as those in the conventional example 2 and the example 1, respectively. The front glass is hard glass, and the two-layer optical interference film and the functionally gradient film both use TiO ₂ and SiO ₂ as film materials, and are the same films as in the conventional example 2 and the example 1, respectively. It was composed.

The color temperature was measured in the same manner as in the conventional example 2 and the example 1 by turning on the lamp with a lamp power of 150 W and at two incident angles of 0 ° and 30 °.
The spectrophotometer light-receiving portion 15 is arranged at a position where the center point 8 of the arc tube 1 of the metal halide lamp 16 is always seen, and the perpendicular line from the center point 8 to the front glass 18 and the light-receiving portion 15 are the center points 8.
The angle at which the straight line matching the angle of view coincides with the angle of incidence was set as 0 °. The incident angle exceeding 30 ° was not measured due to the arrangement of the light receiving unit 15. In FIG. 10, 13 and 14 represent the paths of the light having the incident angles of 0 ° and 30 °, respectively. Table 4 shows the color temperature measurement results.

[0044]

[Table 4]

As can be seen from Table 4, in the case of the two-layer optical interference film (conventional example 3), the color temperature drops to 3860K when the incident angle is 0 °, but when the incident angle increases to 30 °, the Color temperature increased by just over 200K. On the other hand, in the case of the functionally gradient film of the present invention (Example 2), when the incident angle is 0 °, it is 3820K, and even if the incident angle is increased to 30 °, its color temperature hardly increases. It was In this way, the functionally graded film formed on the front glass surface is the same as when formed on the sleeve surface.
It was confirmed that it has an excellent color temperature conversion action that is not affected by changes in the incident angle of light.

In the metal halide lamp and the metal halide lamp housed in the lighting device according to the present invention,
The kind of the enclosed substance in the arc tube is not limited to the substance of the above-mentioned embodiment, but may be a combination of other substances such as a combination of mercury, argon, sodium iodide, thallium iodide and indium iodide. Good. Furthermore, the dimensions and shapes of lamp components such as arc tubes and sleeves are
Similar effects can be obtained even in cases other than those of the above-mentioned embodiment. And, it goes without saying that the lamp characteristics such as the lamp power of the metal halide lamp are not limited to those of the above embodiment. The posture of the metal halide lamp housed in the lighting fixture is horizontal in the above-mentioned embodiment, but the same effect can be obtained when it is vertical.

Further, in the metal halide lamp according to the present invention, the portion where the functionally gradient film is formed is not limited to the surface of the sleeve shown in the above embodiment, but an arc tube,
In addition, the functionally gradient film may be formed on at least one surface of the member group including all the translucent members surrounding the arc tube, such as the sleeve and the outer bulb. Therefore, the metal halide lamp according to the present invention does not have to have a sleeve, and in that case, a functionally gradient film may be formed on the surface of at least one of the arc tube and the outer bulb. As a modified example of the metal halide lamp according to the present invention, a sleeve is not provided and the outer bulb (envelope) is doubled. You may take the form that the functionally gradient film is formed on the surface. Also in the luminaire according to the present invention, it is not limited to the case where the functionally gradient film is formed only on the front glass as in the above embodiment, and at least the functionally gradient film is formed on the front glass. This is an essential requirement, and for example, the functionally gradient film may be formed not only on the front glass but also on the sleeve of the metal halide lamp housed inside.

The location of the functionally gradient film formation is not limited to the outer surface in the case of the sleeve, but may be the inner surface or both the inner and outer surfaces. Also, when the functionally gradient film is formed on the outer sphere, either the inner surface, the outer surface, or both may be used. Further, also in the case of the front glass of the lighting fixture, the functionally gradient film forming portion may be not only the surface facing the outside of the lighting fixture as in the above-described embodiment, but also the surface facing the inside, It may be formed on both sides. As for the arc tube only, a functionally graded film is formed on the outer surface of the arc tube after completion of the arc tube due to reasons such as difficulty in manufacturing the lamp when a film is formed on the inner surface and deterioration of film quality during operation of the arc tube. Preferably. There is no limitation on the material of the substrate on which the functionally gradient film is formed, and any material having transparency such as quartz glass, hard glass, and soft glass can be used.

The functionally gradient film according to the present invention is not limited to the film structure of the above-mentioned embodiment, and may have another film structure. That is, first, the film substance is not limited to the two components of titanium oxide (TiO ₂ ) and silicon dioxide (SiO ₂ ) of the above-mentioned embodiment, but is generally used as a thin film constituent material, and includes vacuum deposition method, sputtering method, and CVD method. Any substance may be used as long as a film can be formed by a known method such as, and may be composed of not only two components but also three or more components. Therefore, although there are many kinds of film substances and combinations thereof that can be used, the combination of substances having similar refractive index values is less effective as a functionally gradient film, and thus the refractive index values are different from each other. A combination of substances is preferred.

Of the combinations other than TiO ₂ —SiO ₂ ,
Some of the most preferable combinations in the present invention are listed, zirconium oxide (ZrO ₂ ) -SiO ₂ , tantalum oxide (Ta ₂ O ₅ ) -SiO ₂ , niobium oxide (Nb ₂ O ₅ ) -Si.
O _2, silicon nitride (Si ₃ N ₄₎ is -SiO _2. Besides this,
_{2 such as} cerium oxide (CeO ₂ ) -cerium fluoride (CeF ₃ ), zinc sulfide (ZnS) -magnesium fluoride (MgF ₂ ).
A combination of component systems may be used. Depending on the purpose, for example, aluminum oxide (Al
₂ O ₃ ) -added TiO ₂ —Al ₂ O ₃ —SiO ₂ 3 component system may be combined. The film thickness of the functionally gradient film is not limited in the present invention, and various film thicknesses can be used according to the purpose.

Further, the compositional percentage curve of the functionally gradient film according to the present invention is not limited to the asymmetric V-shaped one in the above embodiment, and one having an optimum compositional distribution may be selected according to the purpose. Good. Generally, the functionally gradient film according to the present invention is not limited to a metal halide lamp and can be provided for any light source, and the color temperature thereof is largely converted,
A characteristic effect of maintaining the converted color temperature value less affected by changes in the incident angle of light can be produced. However, this is not always possible, and it is necessary to select a film configuration that exhibits optimum spectral transmission characteristics that match the emission spectral distribution of the target light source and the target color temperature value. ..

Any of the conventionally known film forming methods can be used for forming the functionally graded film according to the present invention, but the vacuum vapor deposition method and the sputtering method are capable of precise film thickness control. Alternatively, it is preferable to use the CVD method.

[0053]

As described above on the basis of the embodiments,
The metal halide lamp according to the present invention is an arc tube, and, for example, at least one surface of all translucent members surrounding the arc tube, such as a sleeve and a lamp outer bulb, and a lighting fixture according to the present invention is Metal halide lamp arc tube,
For example, since the functionally gradient film is formed on at least the surface of the front glass among all the translucent members surrounding the arc tube, such as the sleeve and the outer bulb, and the front glass, the case without the functional gradient film is taken as a reference. The degree of decrease in the color temperature of the metal halide lamp is larger than that in the case where the conventional optical interference multilayer film is formed, and the change in the color temperature of the metal halide lamp with the change of the angle of viewing the emission center of the metal halide lamp. Is small and realizes a substantially constant color temperature that does not cause discomfort in any irradiation direction, which is a unique effect that cannot be obtained by the conventional optical interference multilayer film.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of a metal halide lamp according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of calculated values of a spectral transmittance curve when a conventional 7-layer optical interference film is used.

FIG. 3 is a diagram showing an example of calculated values of a spectral transmittance curve when a conventional two-layer optical interference film is used.

FIG. 4 is a diagram showing an example of a composition percentage curve in a film thickness direction of a functionally gradient film according to the present invention.

FIG. 5 is a diagram showing an example of calculated values of a spectral transmittance curve when a functionally gradient film according to the present invention is used.

FIG. 6 is a diagram showing an example of actually measured values of an emission spectral distribution in a metal halide lamp with and without a functionally gradient film.

FIG. 7 is a diagram showing an example of a system configuration of a vacuum vapor deposition apparatus used for forming a functionally gradient film according to the present invention.

FIG. 8 is a diagram showing an example of actually measured values of a spectral transmittance curve of a functionally gradient film according to the present invention.

FIG. 9 is a diagram showing a color temperature measuring method of the metal halide lamp of Example 1 of the present invention.

FIG. 10 is a diagram showing a lighting fixture according to a second embodiment of the present invention in which a metal halide lamp is housed and a front glass with a film is attached.

[Explanation of symbols]

 1 arc tube 2,3 electrode 4,5 heat insulating film 6 sleeve 7 functionally graded film 8 arc tube center point 15 spectrophotometer light receiving part 16 metal halide lamp 17 mirror 18 front glass 19 functionally graded film

Claims (4)

[Claims] 1. A metal halide lamp comprising at least an arc tube containing mercury, a rare gas, and a metal halide, and an outer bulb containing the arc tube. The arc tube and the arc tube are surrounded by the arc tube. A metal halide lamp characterized in that a functionally gradient film is formed on the surface of at least one member of a member group consisting of all translucent members. 2. A metal halide lamp comprising an arc tube in which mercury, a rare gas, and a metal halide are enclosed, a glass cylinder surrounding the arc tube, and an outer bulb containing the arc tube and the cylinder. A metal halide lamp, wherein a functionally gradient film is formed on the surface of at least one member of the member group consisting of the arc tube, the cylinder, and the outer sphere. 3. A luminaire having a front glass, wherein a metal halide lamp having mercury, a rare gas and a metal halide enclosed therein is housed in an arc tube, and a functionally gradient film is formed on at least the surface of the front glass. Lighting equipment that is characterized. 4. The functionally graded film is made of titanium oxide (Ti
O ₂ ), zirconium oxide (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), niobium oxide (Nb ₂ O ₅ ), and at least one substance selected from the group consisting of silicon nitride (Si ₃ N ₄ ), becomes because the silicon dioxide (SiO _2), luminaire metal halide lamp or claim 3, wherein according to claim 1 or 2, wherein the composition ratio in the thickness direction is composed of continuously varying film ..