JP2971773B2 - Multilayer film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly durable multilayer film provided on the surface of a reflecting substrate of a reflecting mirror such as a lamp with a reflecting mirror used in a floodlighting device.

[0002]

2. Description of the Related Art As is well known, a projector, a lighting device for a store,
Alternatively, a floodlighting device such as a medical lighting device is provided with a light source with a reflector, and a reflector having a multilayer film is provided behind the light source. In this reflecting mirror, much of the visible light emitted from the light source is reflected forward, and long-wavelength infrared light is transmitted backward. For this reason, such a floodlighting device emits visible light, which contains almost no infrared light, that is, so-called cold light, so that the illuminated object is less heated. Lighting with reduced loss is realized.

The reflecting mirror used in the above floodlighting device is composed of a high refractive index thin film made of a high refractive index material and a low refractive index thin film made of a low refractive index material alternately laminated on the surface of a reflecting substrate. The higher the ratio of the refractive indexes of the two materials to be laminated, the higher the reflectance and the wider the reflection area.

[0004] Table 1 shows the ratio of the refractive index to the combination of substances used in such a multilayer film.

[0005]

[Table 1]

The multilayer film is usually formed on the concave surface of the reflective substrate by a so-called gas scattering vapor deposition method, which is performed by vapor deposition in a gas atmosphere having a pressure of 10 ^-1 Pa class, and is uniformly formed on the surface of the reflective substrate. Is adhered to.

As shown in Table 1, the multilayer film is composed of a ZnS-MgF ₂ alternate layer in which a zinc sulfide (ZnS) thin film and a magnesium fluoride (MgF ₂ ) thin film are alternately laminated, or a zinc sulfide thin film. and so-called soft coat film of silicon oxide (SiO ₂₎ ZnS-SiO ₂ alternate layers alternately stacked and a thin titanium oxide (TiO ₂₎ TiO ₂ -SiO ₂ having a thin silicon oxide film are stacked alternately It is classified into a so-called hard coat film of an alternating layer or a TiO ₂ -MgF ₂ alternating layer in which a titanium oxide thin film and a magnesium fluoride thin film are alternately laminated.

[0008] Each multilayer film is selected and used according to its characteristics.

<Soft coat film> ZnS-MgF ₂ alternating layer; excellent in moisture resistance but inferior in heat resistance, so it is applied to a low-power, long-life halogen lamp having a low heat load and a long life. ZnS-SiO ₂ alternating layer; therefore has excellent heat resistance but inferior in moisture resistance, is applied to a high output and short life-type halogen lamp heat load is a high short-lived.

<Hard coat film> TiO ₂ -SiO ₂ alternating layer; excellent in moisture resistance and heat resistance, and applied to a light source which has a high heat load and a long life, such as a metal halide lamp and a high power / long life halogen lamp. Is done. TiO ₂ -MgF ₂ alternating layer; a high-power, long-life halogen lamp that is slightly inferior to the TiO ₂ -SiO ₂ alternating layer, but has better moisture resistance and heat resistance than a soft coat film, and has a high heat load and a long life. Applied to

Further, Table 2 shows the results of evaluating the moisture resistance and heat resistance of each of the above multilayer films.

[0012]

[Table 2]

[0013] Here, the moisture resistance of (Table 2) is 50 ° C.
It shows the time of peeling of the film when left in an atmosphere of 90 ° C. and 90% humidity. The heat resistance is 300 ° C. (using a 100 W halogen lamp) and 350 ° C.
The times at which film peeling occurs at a temperature of 300C (using a 300 W halogen lamp) are shown.

As the output of the light source increases and the life of the light source increases, the TiO ₂ —SiO ₂ alternating layer or the TiO ₂
Hard coat films of _2- MgF ₂ alternating layers have been used.

However, in the hard coat film of the TiO ₂ —SiO ₂ alternate layer and the TiO ₂ —MgF ₂ alternate layer,
Splash when bumping TiO ₂ thin film
Is likely to occur and may damage the reflective substrate, making the manufacturing apparatus and process more complicated than the soft coat film,
Manufacturing costs increase. In addition, the refractive index of the TiO ₂ thin film easily changes depending on the heating temperature of the reflective substrate, and it is difficult to obtain desired optical characteristics.

For this reason, the quality of the soft coat film is made to approach the durability of the hard coat film. For example, Japanese Patent No. 1779691 discloses that ZnS
(ZnS + ZrO ₂ ) thin film to which rO ₂ is added and MgF ₂
The thin films were alternately laminated, and the thus formed (ZnS
It has been shown that the durability performance is improved by using a + ZrO ₂ ) -MgF ₂ alternate layer as a multilayer film.

However, as shown in (Table 3), the durability is improved by adding ZrO ₂ to ZnS at a ratio of 99: 1. There is a demand for realizing a multilayer film having a higher durability performance with a soft coat film, which does not reach the durability performance.

[0018]

[Table 3]

[0019]

As described above, a multilayer film formed of a hard coat film has high durability but is difficult to manufacture, and is expensive. Further, a multilayer film formed of a soft coat film is difficult to manufacture. It has good properties, but not enough durability. In view of such circumstances, the present invention has been made, and the object thereof is to have good manufacturability constituted by a soft coat film,
An object of the present invention is to provide a multilayer film having high durability.

[0020]

Means for Solving the Problems] multilayer film of the present invention, the light projecting
In a multilayer film formed by alternately laminating high-refractive-index thin films and low-refractive-index thin films so as to form a soft coat film on a surface of a reflecting substrate of a lighting device facing a light source, The refractive index thin film is made of zinc sulfide containing 0.05 to 10% by weight of tin oxide.

[0021]

The multilayer film having the above-mentioned structure is formed by alternately stacking high-refractive-index thin films and low-refractive-index thin films made of zinc sulfide containing 0.05 to 10% by weight of tin oxide to form a soft coat film. Has formed. Therefore, if the tin oxide content is 0.05% by weight or more, the durability is improved on the basis that it is presumed to have an effect of blocking the oxidation of zinc sulfide due to heat and the adsorption of moisture, and conversely, the tin oxide has an effect of 0.1%. If it is less than 05% by weight, no improvement in durability can be seen. Further, when the content of tin oxide is 20% by weight or more, the film is cracked at the stage when the film is formed, and the durability becomes low. On the other hand, when the content of tin oxide is 15% by weight or more, the refractive index is remarkably reduced, which is not preferable when a high refractive index thin film having a large difference from a low refractive index thin film is to be obtained. Therefore, tin oxide is added to the high refractive index thin film in an amount of 0.05 to 1
By using zinc sulfide containing 0% by weight, there is no danger of splash during film formation, no danger of damaging the reflective substrate, and the manufacturing apparatus and process are not relatively complicated, and the manufacturing cost is low. It is possible to realize a multi-layer film having high durability performance with good productivity which does not increase by a soft coat film.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a sectional view of a lamp with a reflecting mirror of a floodlighting device, FIG. 2 is a partially enlarged sectional view schematically showing the reflecting mirror, and FIG. 3 shows the refractive index of a zinc sulfide film containing tin oxide. FIG.

In FIG. 1, reference numeral 1 denotes a lamp with a reflecting mirror of a floodlighting apparatus using a halogen lamp 2 as a light source.
Is a reflecting mirror opposite the halogen lamp 2.
The reflecting mirror 3 is constituted by a reflecting substrate 4 having an inner surface integrally formed of hard glass and forming a paraboloid of revolution, and a multilayer film 6 is applied to an inner surface 5 thereof. The reflecting mirror 3 has a base 7 projecting from the rear thereof, and the base 7 has a mounting hole 8 for mounting the halogen lamp 2.

On the other hand, in the halogen lamp 2, a tungsten coil filament 10 is sealed in a bulb 9 made of heat-resistant glass such as quartz glass, and one end thereof is crushed and sealed to form a sealing portion 11. Then, the sealing portion 11 is attached to the mounting hole 8.
The halogen lamp 2 is attached to the reflecting mirror 3 by inserting the halogen lamp 2 into the reflector 3 and fixing the halogen lamp 2 with the heat-resistant adhesive 12. Reference numeral 13 denotes a conductive wire connected to both ends of the tungsten coil filament 10 of the halogen lamp 2 and is led out of the sealing portion 11 exposed at the end of the base 7.

The multilayer film 6 provided on the reflecting mirror 3 is
0.05 tin oxide (SnO ₂ ) on the inner surface 5 of the reflective base 4
And the high refractive index film H composed by 10% the contained was zinc sulfide (ZnS) film, magnesium fluoride (MgF ₂₎ has a low refractive index film L ₁ made of a thin film by alternately stacking (ZnS
+ SnO ₂ ) —a so-called soft coat film of alternating layers of MgF ₂ .

Each of the thin films H and L ₁ has an alternate layer design with an optical thickness of １ ／ λ, and the reflecting substrate 4 (HL ₁ ) ⁶ Hλ ₁ (L ₁ H) ⁴ λ _2.
It is composed of air. Note that λ ₁ and λ ₂ are design wavelengths
₁ is 600 nm and λ ₂ is 450 nm. The deposition of the thin films H and L ₁ is performed six times alternately with H and L ₁ , one more layer of H is added to form 13 layers, and then L ₁ and H are alternately performed four times, for a total of 8 times. The multilayer film 6 has a total of 21 layers.

Usually, vacuum deposition is used to form such a multilayer film 6, and the deposition conditions in this embodiment are as follows: degree of vacuum: 2.67 × 10 ^{−1 to} 1.07 × 10 ⁻³ P
a Scattering gas: argon Substrate temperature: 150 to 200 ° C. Evaporation source: electron beam (electron gun), and after vapor deposition, heat treatment was performed at 400 ° C. for 1 hour in an electric furnace.

Next, a durability test of moisture resistance and heat resistance was performed on the multilayer film 6 of this embodiment, and the results are shown in Table 4.
As shown in FIG. The moisture resistance is the time when the film peels off when left in an atmosphere at a temperature of 50 ° C. and a humidity of 90%.
This is the time at which film peeling occurs at 50 ° C. Also (table
4), the high refractive index thin film H is a zinc sulfide thin film containing 0.01 to 20% by weight of tin oxide (ZnS + Sn)
O ₂₎ MgF ₂ is shown for alternating layers.

[0029]

[Table 4]

On the other hand, the refractive index of a zinc sulfide single layer film containing tin oxide of 0 to 90% by weight was measured. This is the same deposition condition as in the above embodiment, that is, the degree of vacuum: 2.67 × 10 ^{−1 to} 1.07 × 10 ⁻³ P
a Scattering gas: argon Substrate temperature: 150 to 200 ° C Evaporation source: After deposition treatment with an electron beam (electron gun), heat treatment at 400 ° C for 1 hour in an electric furnace is performed, and zinc oxide monolayer containing tin oxide is applied. A film was formed, and the film was measured. The measurement results were as shown in FIG.

From Table 4, it can be seen that the durability is not improved when the content of tin oxide in the zinc sulfide is less than 0.05% by weight. This is because the tin oxide contained is 0.05
It is considered that when the content is not less than% by weight, zinc sulfide has an effect of blocking oxidation by heat and adsorption of moisture, and durability is remarkably improved. Further, when the content is 20% by weight or more, cracks occur in the film at the stage of film formation, and peeling of the film occurs in a short time in the durability test.

As shown in FIG. 2, when the amount of tin oxide contained in zinc sulfide is 15% by weight or more, the refractive index is remarkably reduced, and when the multilayer film 6 is formed, the refractive index ratio becomes small and cold light is reflected forward. The function as a reflecting mirror (cold light mirror) cannot be satisfied.

Therefore, tin oxide is added to zinc sulfide in an amount of 0.05 to 1
By containing 0% by weight, the function as a cold light mirror can be sufficiently satisfied, and the multilayer film 6 having high moisture resistance and heat resistance and closer to the durability performance of the hard coat film can be obtained by the soft coat film. For this reason, the multilayer film 6 having excellent durability can be obtained without going through complicated manufacturing apparatuses and processes and without increasing the manufacturing cost.

When the lamp 1 with the reflecting mirror having the multilayer film 6 formed as described above is turned on, most of the visible light of the light emitted from the halogen lamp 2 is reflected by the multilayer film 6 of the reflecting mirror 3. Light of a long wavelength infrared region passes through the multilayer film 6 and the reflective base 4 and travels backward. As a result, visible light substantially free of infrared light, that is, so-called cold light, is emitted forward from the lamp 1 with a reflecting mirror, so that the illuminated object is less heated and less likely to cause heat loss.

Next, a second embodiment will be described. This embodiment is a multilayer film of a reflecting mirror in a lamp with a reflecting mirror of a floodlighting device configured in the same manner as the first embodiment, although not shown.
The structure of the multilayer film, particularly the constituent material of the low refractive index thin film, is different. Hereinafter, the multilayer film will be described.

The multilayer film provided on the reflecting mirror is a high refractive index thin film H composed of a zinc sulfide (ZnS) thin film containing 0.05 to 10% by weight of tin oxide (SnO ₂ ) on the inner surface of the reflecting substrate.
And a low refractive index thin film L _{2 made of a} silicon oxide (SiO ₂ ) thin film
And (ZnS + SnO ₂ ) -SiO ₂
It is a so-called soft coat film of alternating layers.

Each of the thin films H and L ₂ has an alternate layer design in which the optical film thickness is 同 じ く λ as in the first embodiment, and the reflecting substrate 4 · (HL ₂ ) ⁶ Hλ ₁ · (L ₂ H ) ⁴ λ ₂・
It is composed of air. Note that λ ₁ and λ ₂ are design wavelengths
₁ is 600 nm and λ ₂ is 450 nm. The deposition of each of the thin films H and L ₂ is performed alternately with H and L ₂ six times, and one layer of H is further added to form a 13 layer, and then L ₂ and H are alternately repeated four times, for a total of 8 times. The multilayer film 6 has a structure of a total of 21 layers, and is adhered to the inner surface of the reflective substrate by vacuum evaporation under the same evaporation conditions as in the first embodiment.

Further, the results of the durability test of the moisture resistance and the heat resistance of the multilayer film of this embodiment are shown in (Table 4), and the test conditions are the same as those of the first embodiment. . Table 4 shows that the high-refractive-index thin film H contains tin oxide 0.0%.
A zinc sulfide thin film containing 1 to 20% by weight (ZnS
+ SnO ₂ ) -SiO ₂ alternating layers are shown.

As a result, it can be seen that also in this embodiment, when the tin oxide contained in the zinc sulfide is less than 0.05% by weight, the durability is not improved. And the contained tin oxide is 0.0
It is considered that when the content is 5% by weight or more, as in the first embodiment, zinc sulfide has an effect of blocking heat oxidation and moisture adsorption, and the durability is remarkably improved.
Further, when the content is 20% by weight or more, cracks occur in the film at the stage of film formation, and peeling of the film occurs in a short time in the durability test.

When the amount of tin oxide contained in zinc sulfide is 15% by weight or more, the refractive index is remarkably reduced. When a multilayer film is formed, the refractive index ratio becomes small, and the reflecting mirror functions as a cold light mirror. I am not satisfied.

Therefore, in the present embodiment, the function as a cold mirror can be sufficiently satisfied by adding 0.05 to 10% by weight of tin oxide to zinc sulfide, and the hard coat film has high moisture resistance and heat resistance. A multilayer film closer to the durability performance can be obtained by the soft coat film. Therefore, a multilayer film having excellent durability can be obtained without going through complicated manufacturing apparatuses and processes, and without increasing manufacturing costs.

By using a reflector-equipped lamp provided with a reflector having a multilayer film as described above, cold light, which is visible light substantially containing no infrared light, is emitted forward, The illuminated object is less heated and less likely to cause heat loss.

As described above, according to the present invention, the infrared light with improved durability can be obtained without a complicated manufacturing apparatus or process, and without increasing the manufacturing cost. And a multi-layer film of a soft coat film that can reflect visible light and hardly contains any.

[0044]

As is clear from the above description, the present invention provides a soft coating by alternately laminating high-refractive-index thin films and low-refractive-index thin films of zinc sulfide containing 0.05 to 10% by weight of tin oxide. By forming so as to form the coat film, it is possible to obtain effects such as good productivity and high durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a reflector-equipped lamp of a floodlighting device according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view schematically showing the reflector according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a refractive index of a zinc sulfide film containing tin oxide according to an example of the present invention.

[Explanation of symbols]

1 ... reflector with lamp 3 ... reflecting mirror 4 ... reflective substrate 5 ... inner surface 6 ... multilayer H ... high refractive index film L _1, L ₂ ... low-refractive index thin film

Claims (1)

(57) [Claims] 1. A light source for a reflecting base of a reflecting mirror for a floodlighting device.
In a multilayer film in which high-refractive-index thin films and low-refractive-index thin films are alternately laminated so as to form a soft coat film on the surface opposed to the above, the high-refractive-index thin film is formed of tin oxide of 0.05 to 10 nm.
What is claimed is: 1. A multilayer film comprising zinc sulfide containing 1% by weight.