JP2021150190A - Heat emission light source - Google Patents

Abstract

To provide a heat emission light source which can be installed in a state where a substrate and a heat emission layer are exposed in atmosphere, has a large emissivity in a wavelength of larger than 4 μm and 8 μm or smaller, and has a small emissivity in a wavelength of larger than 8 μm.SOLUTION: In an emission control part Na, a heat emission layer N and a substrate K heating the heat emission layer N are laminated, and a MIM lamination part M that the heat radiation layer N makes a resonance transparent oxide layer R formed with a transparent oxide position between platinum layers P arranged along a lamination direction is provided. In a formation that it is positioned at the side close to the substrate K in order of a discharge transparent oxide layer Nb formed by the transparent oxide, it is structured in a state where the emission control part Na and the discharge transparent oxide layer Nb are laminated. The thickness of the resonance transparent oxide layer R is 1200 nm or larger and 1500 nm or smaller, in which the region of larger than 4 μm and 8 μm or smaller is set as a resonance wavelength region.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermal radiant light source in which a thermal radiant layer and a substrate for heating the thermal radiant layer are laminated.

Such a thermal radiation light source radiates radiant light for heating an object to be heated from the thermal radiation layer by heating the thermal radiation layer to a high temperature state on a substrate.
As such a heat radiation light source, a substrate and a heat radiation layer are arranged in a sealed state inside a sealing tube formed of a translucent airtight member such as quartz glass, and the inside of the sealing tube is put into a vacuum state. Alternatively, there is a sealing tube in which an inert gas such as nitrogen gas is sealed (see, for example, Patent Document 1).

In Patent Document 1, the substrate is made of a refractory metal such as tungsten that generates heat when a current is passed, and the thermal radiant zone is formed of a metal layer such as tantalum or molybdenum. By arranging it inside the sealing tube in the sealed state, deterioration due to oxidation of the substrate and the thermal radiation layer is prevented.

JP-A-2015-138638

In the conventional thermal radiation light source, the substrate and the thermal radiation layer are arranged inside the sealing tube in a sealed state, so that the entire structure is complicated and expensive. Therefore, the substrate and the thermal radiation layer are placed in the atmosphere. There is a demand for a thermal radiation light source that can be installed in an exposed state.

Further, for the purpose of heating the object to be heated with infrared rays, etc., it is large in a narrow band wavelength larger than 4 μm and 8 μm or less (that is, a narrow band wavelength excluding the short wavelength side of the mid-infrared light). There is a demand for a thermal radiation light source having an emissivity (emissivity) and a small emissivity (emissivity) for a wavelength larger than 8 μm (that is, far-infrared light).

The present invention has been made in view of the above circumstances, and an object of the present invention is that the substrate and the heat radiant layer can be installed in a state of being exposed to the atmosphere, and the wavelength in a region larger than 4 μm and 8 μm or less. The point is to provide a thermal radiation light source having a large radiation rate and a small radiation rate at a wavelength larger than 8 μm.

The thermal radiant light source of the present invention is obtained by laminating a thermal radiant layer and a substrate for heating the thermal radiant layer, and its characteristic configuration is as follows.
The thermal radiation layer includes a MIM laminated portion in which a transparent oxide layer for resonance formed of a transparent oxide is located between a pair of platinum layers arranged along the stacking direction of the thermal radiation layer and the substrate. The radiation control unit and the radiation transparent oxide layer formed of the transparent oxide are positioned closer to the substrate in this order, and the radiation control unit and the radiation transparent oxide layer are laminated. Configured,
The thickness of the transparent oxide layer for resonance is 1200 nm or more and 1500 nm or less, with a region larger than 4 μm and 8 μm or less as a resonance wavelength region.

That is, the radiation control unit and the radiation transparent oxide layer are laminated in such a manner that the radiation control unit is located closer to the substrate in the order of the radiation control unit including the MIM laminated unit and the radiation transparent oxide layer. When the thermal radiation layer is heated to a high temperature state on the substrate, the radiation control unit including the MIM laminated portion emits radiant light, and the radiant light is transparently oxidized for radiation. It will be radiated from the material layer.

The substrate that becomes hot to heat the thermal radiation layer emits radiant light, but the platinum layer adjacent to the substrate in the MIM laminated part of the radiation control unit shields the radiant light of the substrate and the substrate Since it is suppressed that the radiated light is transmitted to the inside of the radiated control unit, it is suppressed that the radiated light of the substrate affects the radiated light radiated from the radiated control unit.
Further, since the transparent oxide layer for radiation, which has a lower refractive index than platinum and a higher refractive index than air, is located adjacent to the platinum layer located on the side where the transparent oxide layer for radiation exists in the radiation control unit. The reflectance of the platinum layer located on the existing side of the transparent oxide layer for radiation is reduced, and the radiated light radiated from the radiation control unit can be satisfactorily emitted to the outside.

The MIM laminated portion included in the radiation control unit positions the transparent oxide layer for resonance between the pair of platinum layers arranged along the laminating direction of the thermal radiation layer and the substrate, and is transparent for resonance. Since the thickness of the oxide layer is 1200 nm or more and 1500 nm or less, with the region larger than 4 μm and 8 μm or less as the resonance wavelength region, among the radiant light emitted from the platinum layer heated to a high temperature state. It has a large radiation rate (radiation rate) at wavelengths in the resonance wavelength range larger than 4 μm and 8 μm or less, and a small radiation rate (radiation rate) at wavelengths larger than 8 μm (that is, far-infrared light). As a result, radiant light having a resonance wavelength range larger than the amplified 4 μm and 8 μm or less is emitted to the outside from the transparent oxide layer for radiation.

To add an explanation, MIM means a metal integral metal, and the MIM laminated portion emits radiated light having a wavelength in a region larger than 4 μm and 8 μm or less among the radiated light emitted by the platinum layer. By repeatedly reflecting between the platinum layers (inside the transparent oxide layer for resonance) arranged along the stacking direction of the thermal radiation layer and the substrate, the radiant light having a wavelength in the region larger than 4 μm and 8 μm or less is amplified. Therefore, radiant light having a wavelength in the region larger than the amplified 4 μm and 8 μm or less is emitted to the outside from the transparent oxide layer for radiation.

That is, radiant light having a resonance wavelength range larger than 4 μm and 8 μm or less is amplified while being repeatedly reflected between the thermal radiation layer and the platinum layer arranged along the stacking direction of the substrate, and is larger than 4 μm and 8 μm or less. A part of the radiated light having a wavelength in the resonance wavelength range of the above is transmitted to the existing side of the transparent oxide layer for radiation and emitted to the outside from the transparent oxide layer for radiation, and as a result, it is amplified. Radiant light having a wavelength in the resonance wavelength range larger than 4 μm and 8 μm or less is emitted to the outside from the transparent oxide layer for radiation.

On the other hand, of the radiant light emitted from the platinum layer, the radiant light having a wavelength of 4 μm or less or a wavelength larger than 8 μm is less likely to be amplified by the resonance action from the transparent oxide layer for radiation. It will be released to the outside.
As a result, the radiated light emitted to the outside from the transparent oxide layer for radiation has a wavelength in the resonance wavelength range larger than 4 μm and 8 μm or less (that is, a narrow band excluding the short wavelength side of the mid-infrared light). It has a large emissivity (emissivity) at the wavelength) and a small emissivity (emissivity) at a wavelength larger than 8 μm (that is, the wavelength of far-infrared light).

Of the plurality of platinum layers provided in the MIM laminated portion, the platinum layer adjacent to the substrate needs to block the radiated light of the substrate, and the other platinum layers need to transmit a part of the radiated light. Therefore, the platinum layer adjacent to the substrate is formed thicker than the other platinum layers.

In this way, the thermal radiant layer is emitted from the transparent oxide layer for radiation to the outside while amplifying the radiant light having a wavelength in the resonance wavelength range larger than 4 μm and 8 μm or less, and in addition, it is installed in the air. Even so, the optical characteristics can be maintained for a long time by suppressing the deterioration of the radiation control unit and the substrate due to oxidation.

That is, the platinum layer of the MIM laminated portion is formed of platinum, and platinum is installed in the air because the standard Gibbs oxide energy is positively large in all temperature ranges and does not oxidize in the air. However, it does not deteriorate due to oxidation.
Further, even when the transparent oxide layer for radiation and the transparent oxide layer for resonance are formed of a material in which the substrate is oxidized in order to suppress the permeation of oxygen in the air toward the substrate. Therefore, deterioration of the substrate due to oxidation is suppressed over a long period of time.
Therefore, even if the thermal radiant zone is installed in the air, the optical characteristics can be maintained for a long time.

By the way, the platinum forming the platinum layer adjacent to the substrate may flow and aggregate on the substrate when heated to a high temperature, but the transparent oxide layer for resonance acts to suppress the movement of platinum. Platinum, which forms a platinum layer adjacent to the radiation transparent oxide layer on the side where the radiation transparent oxide layer exists with respect to the resonance transparent oxide layer, is a resonance transparent oxide layer when heated to a high temperature. There is a risk of flowing over and agglomerating, but since the transparent oxide layer for radiation exerts the effect of suppressing the movement of platinum, the agglomeration of platinum can be suppressed, and from this point as well, thermal radiation The layer can maintain its optical properties for a long time.

In short, according to the characteristic configuration of the present invention, the substrate and the thermal radiation layer can be installed in a state of being exposed to the atmosphere, and have a large radiance rate in a wavelength region larger than 4 μm and 8 μm or less, and more than 8 μm. It is also possible to provide a thermal radiation light source having a small radiation rate of a large wavelength.

A further characteristic configuration of the thermal radiation light source of the present invention is that a substrate adhesion layer is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control unit.

That is, since the substrate adhesion layer is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control unit, the radiation control unit is peeled off from the substrate when the radiation control unit is heated by the substrate. Can be suppressed.

That is, since the coefficient of thermal expansion of the substrate and the coefficient of thermal expansion of the radiation control unit in which a plurality of thin films are laminated are different, the radiation control unit may be peeled off from the substrate when the radiation control unit is heated on the substrate. However, since the adhesion between the substrate and the platinum layer adjacent to the substrate in the radiation control unit is enhanced by the adhesion layer for the substrate, it is possible to prevent the radiation control unit from peeling off from the substrate.

In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, it is possible to prevent the radiation control unit from peeling off from the substrate.

Further characteristic configurations of the thermal radiation light source of the present invention are the radiation between the platinum layer and the resonance transparent oxide layer in the MIM laminated portion, and the radiation in the radiation transparent oxide layer and the radiation control unit. The point is that an adhesive layer for platinum is laminated on each of the platinum layer adjacent to the transparent oxide layer for use.

That is, the adhesion layer for platinum is between the platinum layer in the MIM laminated portion and the transparent oxide layer for resonance, and the transparent oxide layer for radiation and the platinum layer adjacent to the transparent oxide layer for radiation in the radiation control unit. Since it is provided between the two, when the radiation control unit is heated to a high temperature on the substrate, it is possible to prevent the platinum layer in the MIM laminated unit from flowing and aggregating, and due to the difference in the coefficient of thermal expansion. , It is possible to prevent the platinum layer and the transparent oxide layer for resonance from peeling off, and the transparent oxide layer for radiation and the platinum layer from peeling off.

That is, since the adhesion between platinum and the transparent oxide is low, when the radiation control unit is heated to a high temperature state on the substrate, it becomes a platinum layer adjacent to the transparent oxide layer for resonance or a transparent oxide layer for radiation. Adjacent platinum layers may flow and aggregate, but by stacking the platinum adhesion layers, the adhesion of the platinum layer adjacent to the resonance transparent oxide layer to the resonance transparent oxide layer and radiation By enhancing the adhesion of the platinum layer adjacent to the transparent oxide layer for radiation to the transparent oxide layer for radiation, the platinum layer in the MIM laminated part flows when the radiation control unit is heated to a high temperature state on the substrate. It is possible to suppress the agglomeration, and also to prevent the platinum layer and the transparent oxide layer for resonance from being peeled off, and the transparent oxide layer for radiation and the platinum layer from being peeled off.

In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, when the radiation control unit is heated to a high temperature state on the substrate, the platinum layer in the MIM laminated unit can be suppressed from flowing and aggregating.

A further characteristic configuration of the thermal radiation light source of the present invention is that the adhesion layer for a substrate and the adhesion layer for platinum are formed of titanium.

That is, titanium adheres to the substrate of the platinum layer adjacent to the substrate, adheres to the transparent oxide layer for resonance of the platinum layer adjacent to the transparent oxide layer for resonance, and is adjacent to the transparent oxide layer for radiation. Since the adhesion of the platinum layer to the transparent oxide layer for radiation can be satisfactorily improved and the melting point is as high as 1668 ° C., MIM when the radiation control unit is heated to a high temperature state on the substrate. It is possible to appropriately suppress the flow and aggregation of the platinum layer in the laminated portion.

Incidentally, the titanium forming the substrate adhesion layer and the platinum adhesion layer may be gradually oxidized and changed to titanium oxide by using the thermal radiation light source in the atmosphere. In other words, when a thermal radiation light source is used in the atmosphere, it can be considered that the adhesion layer for the substrate and the adhesion layer for platinum are formed of titanium oxide.
However, not all of the titanium forming the substrate adhesion layer and the platinum adhesion layer changes to titanium oxide, and the titanium in the portion that adheres to the platinum layer is titanium that adheres to the platinum layer without being oxidized. (Metallic state) will be continued.

The substrate adhesion layer and the platinum adhesion layer formed of titanium are formed in a thin film state so as to have light transmission, and the titanium thus formed in the thin film state is oxidized. Although it will change to titanium, since titanium oxide has transparency, even if titanium is changed to titanium oxide, the performance of the thermal radiation layer will not be adversely affected.

In short, according to a further characteristic configuration of the thermal radiation light source of the present invention, when the radiation control unit is heated to a high temperature state on the substrate, the platinum layer in the MIM laminated unit is appropriately suppressed from flowing and aggregating. can.

A further characteristic configuration of the thermal radiant light source of the present invention is that the transparent oxide is aluminum oxide.

That is, since aluminum oxide has a small oxygen diffusion coefficient, oxygen in the atmosphere permeates by using aluminum oxide as the transparent oxide forming the transparent oxide layer for radiation and the transparent oxide layer for resonance. Even when the substrate is made of a material to be oxidized, it is possible to appropriately prevent the surface of the substrate on the side where the radiation control unit is laminated from being deteriorated by oxidation.

In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, it is possible to appropriately prevent the surface of the substrate on the side where the radiation control unit is laminated from being deteriorated by oxidation.

A further characteristic configuration of the thermal radiant light source of the present invention is that the substrate is configured to self-heat when energized.

That is, since the substrate is configured to self-heat when energized, the substrate can be self-heated and the radiation control unit can be heated by energizing the substrate. Since it is not necessary to provide a special external heating unit for heating, the overall configuration can be simplified.

Incidentally, as a material that self-heats when energized, a metal material such as cantal or nichrome can be mentioned, and the substrate can be composed of these materials.

In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, the overall configuration can be simplified.

A further characteristic configuration of the thermal radiant light source of the present invention is that the substrate is configured to be heated by an external heating unit.

That is, since the substrate is heated by the external heating unit, the substrate can be constructed by using various materials such as quartz (silicon dioxide) and sapphire.
That is, the substrate can be configured by using a non-oxidizing material such as quartz (silicon dioxide) or sapphire, and the oxidative deterioration of the substrate can be appropriately suppressed.

In short, according to the further characteristic configuration of the thermal radiation light source of the present invention, oxidative deterioration of the substrate can be appropriately suppressed.

It is a figure which shows the basic structure of a thermal radiant light source. It is a table which shows the structural example in the basic structure of a thermal radiant light source. It is a graph which shows the relationship between the structural example of a thermal radiant light source, and radiant intensity. It is a graph which shows the relationship between the type of transparent oxide of a thermal radiation light source, and radiant intensity. It is a table which shows the example of another structure in the basic structure of a thermal radiant light source. It is a graph which shows the relationship between another structure example of a thermal radiant light source, and radiant intensity. It is a graph which shows the relationship between the type of transparent oxide of a thermal radiation light source, and radiant intensity. It is a figure which shows the specific structure of the thermal radiant light source. It is a figure which shows the change of the adhesion layer for platinum. It is a perspective view which shows the relationship between a thermal radiation light source and a heating electrode. It is a perspective view which shows the relationship between a thermal radiation light source and a heating electrode. It is a perspective view which shows the relationship between a thermal radiant light source and a thermal radiant body. It is a perspective view which shows the relationship between a thermal radiant light source and a high temperature fluid source.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration of thermal radiation light source]
FIG. 1 shows the basic configuration of the thermal radiant light source Q, and the thermal radiant light source Q is configured in a form in which the thermal radiant layer N and the substrate K for heating the thermal radiant layer N are laminated. ..
The thermal radiation layer N is located closer to the substrate K in the order of the radiation control unit Na and the radiation transparent oxide layer Nb formed of the transparent oxide, and the radiation control unit Na and the radiation transparent oxidation It is configured in a state where the material layers Nb are laminated.

The radiation control unit Na positions the transparent oxide layer R for resonance formed of the transparent oxide between the pair of platinum layers P arranged along the stacking direction of the thermal radiation layer N and the substrate K. It is configured to include a part M.
The thickness of the transparent oxide layer R for resonance is set to a thickness of 1200 nm or more and 1500 nm or less, with a region larger than 4 μm and 8 μm or less as a resonance wavelength region.

In the basic configuration of the thermal radiation light source Q shown in FIG. 1, the radiation control unit Na includes one MIM laminated unit M.
That is, in the basic configuration of the thermal radiation light source Q, the platinum layer P, the transparent oxide layer R for resonance, the platinum layer P, and the transparent oxide layer Nb for radiation, which constitute the MIM laminated portion M, are described in this description. In order, they are sequentially laminated on the upper part of the substrate K.
In the following description, the platinum layer P adjacent to the substrate K in the MIM laminated portion M is referred to as a first platinum layer P1, and the platinum layer P adjacent to the radiation transparent oxide layer Nb in the MIM laminated portion M is referred to as a first platinum layer P1. , Called the second platinum layer P2.

Then, by heating the thermal radiation layer N to a high temperature state (for example, 300 ° C.) on the substrate K, the thermal radiation light source Q is configured to emit radiant light H from the thermal radiation layer N.
Specifically, the radiated light H has a large emissivity (emissivity: for example) at a wavelength in a region larger than 4 μm and 8 μm or less (that is, a narrow band wavelength excluding the short wavelength side of the mid-infrared light). It has an emissivity of 0.8) at 5 μm and a small emissivity (emissivity: eg, an emissivity of 0.3 at 10 μm) at wavelengths greater than 8 μm (ie, the wavelength of far-infrared light). It is configured to emit radiant light H.

Further, since the thickness of the transparent oxide layer R for resonance is set to a thickness of 1200 nm or more and 1500 nm or less with a region larger than 4 μm and 8 μm or less as a resonance wavelength region, the radiated light H is 4 μm or less. Radiant light H having a small radiation rate (radiation rate) is emitted at the wavelength of (that is, the wavelength on the short wavelength side of the mid-infrared light).

That is, when the thermal radiation layer N is heated to a high temperature state (for example, 300 ° C.) on the substrate K, the platinum layer P (first platinum layer P1 and second platinum layer P1 and second platinum layer) in the MIM laminated portion M included in the radiation control unit Na. P2) will radiate radiant light.
The thickness of the transparent oxide layer R for resonance included in the MIM laminated portion M is set to a thickness of 1200 nm or more and 1500 nm or less, with a region larger than 4 μm and 8 μm or less as a resonance wavelength region. Of the radiated light of the platinum layer P (first platinum layer P1 and second platinum layer P2) of part M, wavelengths larger than 4 μm and 8 μm or less (that is, the short wavelength side of the mid-infrared light was excluded. Narrowband wavelength) is amplified by resonance.

Therefore, the radiation control unit Na has a large emissivity (emissivity) at a wavelength in a region larger than 4 μm and 8 μm or less (that is, a narrow band wavelength excluding the short wavelength side of mid-infrared light). , Having a small emissivity (emissivity) at wavelengths greater than 8 μm (that is, wavelengths of far-infrared light) and wavelengths of 4 μm or less (that is, wavelengths on the short wavelength side of mid-infrared light). Become.
As a result, the radiant light H whose wavelength in the region larger than 4 μm and 8 μm or less is amplified is emitted to the outside from the transparent oxide layer Nb for radiation.

To add an explanation, MIM means a metal integral metal, and the MIM laminated portion M has a wavelength of the radiated light of the platinum layer P (the first platinum layer P1 and the second platinum layer P2). Radiant light in a region larger than 4 μm and 8 μm or less is repeated between a pair of platinum layers P (first platinum layer P1 and second platinum layer P2) arranged along the stacking direction of the thermal radiation layer N and the substrate K. By reflecting, the radiant light in the region having a wavelength larger than 4 μm and 8 μm or less is amplified, and the amplified radiant light H is emitted to the outside from the transparent oxide layer Nb for radiation.

That is, the radiated light in the region having a wavelength larger than 4 μm and 8 μm or less is between the platinum layers P (first platinum layer P1 and second platinum layer P2) arranged along the stacking direction of the thermal radiation layer N and the substrate K. A part of the radiated light having a wavelength in the region larger than 4 μm and 8 μm or less is transmitted to the existing side of the transparent oxide layer Nb for radiation, and is amplified while being repeatedly reflected in the radiation transparent oxide layer Nb. As a result, the radiant light H in which the wavelength in the region larger than 4 μm and 8 μm or less is amplified is emitted to the outside from the transparent oxide layer Nb for radiation.

On the other hand, of the radiated light emitted by the platinum layer P (first platinum layer P1 and second platinum layer P2), the radiated light having a wavelength larger than 8 μm and a wavelength less than 4 μm is amplified by the resonance action. In a rare state, it is released to the outside from the transparent oxide layer Nb for radiation.
As a result, the radiant light H (radiant light emitted to the outside from the transparent oxide layer Nb for radiation) emitted from the thermal radiant light source Q has a wavelength in a region larger than 4 μm and 8 μm or less (that is, mid-infrared light). It has a large radiation coefficient (radiation rate) in the narrow band wavelength excluding the short wavelength side of the wavelengths, and has a wavelength larger than 8 μm (that is, a wavelength of far infrared light) and a wavelength of 4 μm or less (that is, medium). It has a small radiation rate (radiation rate) at the wavelength on the short wavelength side of the infrared light).

By the way, radiant light is radiated from the substrate K which becomes a high temperature state for heating the thermal radiant layer N, but the transmission of the radiant light to the radiation control unit Na is blocked by the first platinum layer P1. Will be. In other words, the thickness of the first platinum layer P1 is a thickness capable of blocking the radiated light from the substrate K.

Further, since the transparent oxide layer Nb for radiation has a higher refractive index than platinum and a smaller refractive index than air, the platinum layer P (second platinum layer) located on the side where the transparent oxide layer Nb for radiation exists. The reflectance of P2) is reduced, and the radiated light radiated from the radiation control unit Na can be satisfactorily emitted to the outside.

The platinum layer P (first platinum layer P1) adjacent to the substrate K of the platinum layers P (first platinum layer P1 and second platinum layer P2) provided in the MIM laminated portion M is the radiated light of the substrate K. The other platinum layer P (second platinum layer P2) needs to transmit a part of radiated light, so that the platinum layer P (first platinum layer P1) adjacent to the substrate K needs to be shielded. , Since it is formed thicker than the other platinum layer P (second platinum layer P2), the platinum layer adjacent to the substrate K in the platinum layer P (first platinum layer P1 and second platinum layer P2). The radiation intensity of P (first platinum layer P1) is higher than that of other platinum layers P (second platinum layer P2).

[Explanation of structural example of basic configuration]
Next, a structural example in the basic configuration of the thermal radiation light source Q will be described. In the structural example described below, the transparent oxide forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance is alumina (aluminum oxide, Al ₂ O ₃ ). Any substrate K can be used, but the details of the substrate K will be described later.

As shown in the table of FIG. 2, the structural examples described below are four examples of structures 1 to 4. Incidentally, in the table of FIG. 2, the substrate K is layer No1, the first platinum layer P1 is layer No2, the resonance transparent oxide layer R is layer No3, the second platinum layer P2 is layer No4, and the radiation transparent oxide layer. Nb is described as layer No5.
The structure 2 and the structure 3 correspond to the heat radiant light source Q of the present invention, but the structure 1 and the structure 4 are the heat radiant light sources Q described for reference.
^{The radiation intensity (W / sr / m 2} / nm) when the thermal radiation zone N in the structures 1 to 4 is heated to 300 ° C. is shown in FIG. In addition, FIG. 3 also shows the radiation intensity of a blackbody at 300 ° C.

In the thermal emissivity light source Q of the structure 2 and the structure 3, the thickness of the layer No. 3 is 1200 nm and 1500 nm, and as shown in FIG. 3, the wavelength in the region larger than 4 μm and 8 μm or less (that is, of the mid-infrared light). Has a large emissivity (emissivity) in the narrow band wavelength excluding the short wavelength side of It has a small emissivity (emissivity) at the wavelength on the short wavelength side of light).

The thermal radiation light source Q of the structures 1 and 4 has a layer No. 3 having a thickness of 1000 nm, and as shown in FIG. 3, has a wavelength in a region of 4 μm or less (that is, a wavelength on the short wavelength side of the mid-infrared light). ) Has a large emissivity (emissivity).

Further, the structure 5 and the structure 6 will be described as another structural example in the basic configuration of the thermal radiation light source Q. In another structural example described below, the transparent oxide forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance is alumina (aluminum oxide, Al ₂ O ₃ ). Any substrate K can be used, but the details of the substrate K will be described later.

Another structural example will be described below. As shown in the table of FIG. 5, the substrate K is layer No1, the first platinum layer P1 is layer No2, and the resonance transparent oxide layer R is layer No3. The second platinum layer P2 is referred to as layer No4, and the transparent oxide layer Nb for radiation is referred to as layer No5.
Then, FIG. 6 shows ^{the radiation intensity (W / sr / m 2} / nm) when the thermal radiation layer N in the structures 5 and 6 as another structural example is heated to 300 ° C. In addition, FIG. 6 also shows the radiation intensity of a blackbody at 300 ° C.

In the thermal emissivity light source Q of the structures 5 and 6, the thickness of the layer No. 3 is 1200 nm and 1500 nm, and as shown in FIG. 6, the wavelength in the region larger than 4 μm and 8 μm or less (that is, of the mid-infrared light). Has a large emissivity (emissivity) in the narrow band wavelength excluding the short wavelength side of It has a small emissivity (emissivity) at the wavelength on the short wavelength side of light).

In the structure 2 of the structural example described above, the thickness of the second platinum layer P2 is 10 nm, whereas the structure 3 of the structural example described above and the structures 5 and 6 of another structural example are , The thickness of the second platinum layer P2 is 5 nm.

Since the first platinum layer P1 shields the radiated light of the substrate K and suppresses the radiated light of the substrate K from passing through the inside of the radiation control unit Na, the preferable range of the thickness thereof is, for example, 10 nm or more is preferable, and 50 nm is more preferable.
Further, since the second platinum layer P2 controls the reflection and transmission of radiated light, the preferable range of the thickness thereof is, for example, 1.5 nm or more, preferably 18 nm or less, and particularly 5 nm or more. 10 nm or less is more preferable.

Since the transparent oxide layer Nb for radiation exists for antireflection and improvement of durability, the preferable range of the thickness thereof is, for example, 100 nm or more, preferably 800 nm or less, and particularly 300 nm or more. , 800 nm or less is more preferable.

When the thickness of the second platinum layer P2 is as thin as 10 nm or less, the reflectance of the platinum layer P (the first platinum layer P1 and the second platinum layer P2) to the radiated light becomes low, so that it is transparent for radiation. It is considered that the oxide layer Nb is unnecessary, but from the viewpoint of durability, the transparent oxide layer Nb for radiation is required.
That is, when the platinum forming the second platinum layer P2 is heated to a high temperature, it may flow and aggregate on the resonance transparent oxide layer R, but the radiation transparent oxide layer Nb is made of platinum. Since it exerts an action of suppressing movement, it is possible to suppress the aggregation of platinum.
Then, in order to suppress the aggregation of platinum, it is preferable that the thickness of the transparent oxide layer Nb for radiation is 100 nm or more.

However, as the thickness of the transparent oxide layer Nb for radiation increases, the radiation intensity of a wavelength larger than 8 μm (that is, the wavelength of far-infrared light) increases, so that the transparent oxide layer Nb for radiation increases. The thickness of the light is preferably 800 nm or less.

[Types of transparent oxides]
_{In the above-mentioned structural example, alumina (aluminum oxide, Al 2} O ₃ ) was exemplified as the transparent oxide forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance.
As the transparent oxide, instead of alumina, tantalum pentoxide (Ta ₂ O ₅ ), silicon dioxide (SiO ₂ ), niobium pentoxide (NbO ₅ ), magnesium oxide (MgO), titanium oxide (TIO ₂ ), and oxidation Hafnium (HfO ₂ ) can be preferably used.
Since alumina (Al ₂ O ₃ ) and titanium oxide (TiO ₂ ) have a small oxygen diffusivity, they are particularly suitable as transparent oxides for forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance. preferable.

In FIG. 4, the thickness of the transparent oxide layer Nb for radiation is 500 nm, the thickness of the second platinum layer P2 is 10 nm, the thickness of the transparent oxide layer R for resonance is 1200 nm, and the thickness of the first platinum layer is shown. In a structure with an arbitrary substrate K of 100 nm, the transparent oxide forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance is changed to the above-mentioned various materials, and the thermal radiation layer is used. The radiation intensity (W / sr / m ² / nm) when N is heated to 300 ° C. is shown. In addition, FIG. 4 also shows the radiation intensity of a blackbody at 300 ° C.
Incidentally, the structural example shown in FIG. 4 has a structure similar to the above-mentioned structure 2, and in the structure 2, the thickness of the first platinum layer P1 is 50 nm, whereas the structural example shown in FIG. 4 is. , The thickness of the first platinum layer P1 is 100 nm.

As shown in FIG. 4, when the transparent oxide is changed to various materials, even if the thickness of the transparent oxide layer R for resonance is the same (1200 nm), the peak wavelength that resonates is silicon dioxide (SiO). ₂ ), Alumina (aluminum oxide, Al ₂ O ₃ ), magnesium oxide (MgO), hafonium oxide (HfO ₂ ), niobium pentoxide (NbO ₅ ), tantalum pentoxide (Ta ₂ O ₅ ) in this order on the long wavelength side. Will move to.
The resonating peak wavelengths of tantalum pentoxide (Ta ₂ O ₅ ) and titanium oxide (TiO ₂ ) are substantially the same.

Incidentally, the peak wavelength of silicon dioxide (SiO ₂ ) is 4.1 μm, the peak wavelength of alumina (aluminum oxide, Al ₂ O ₃ ) is 4.5 μm, and the peak wavelength of magnesium oxide (MgO) is 4.5 μm. It is 4.7 μm, _{the peak wavelength of hafnium oxide (HfO 2} ) is 5.4 μm, the peak wavelength of niobium pentoxide (NbO ₅ ) is 5.8 μm, and the peak wavelength of titanium oxide (TiO ₂ ) is 5.8 μm. , 6.1 μm, and _{the peak wavelength of tantalum pentoxide (Ta 2} O ₅ ) is 6.1 μm.

In FIG. 7, the thickness of the transparent oxide layer Nb for radiation is 100 nm, the thickness of the second platinum layer P2 is 5 nm, the thickness of the transparent oxide layer R for resonance is 1200 nm, and the thickness of the first platinum layer is shown. In a structure with an arbitrary substrate K of 100 nm, the transparent oxide forming the transparent oxide layer Nb for radiation and the transparent oxide layer R for resonance is changed to the above-mentioned various materials, and the thermal radiation layer is used. The radiation intensity (W / sr / m ² / nm) when N is heated to 300 ° C. is shown. In addition, FIG. 7 also shows the radiation intensity of a blackbody at 300 ° C.
Incidentally, the structural example shown in FIG. 7 is a structure corresponding to the above-mentioned structure 5.

As shown in FIG. 7, when the transparent oxide is changed to various materials, even if the thickness of the transparent oxide layer R for resonance is the same (1200 nm), the peak wavelength that resonates is silicon dioxide (SiO). _2), alumina (aluminum _oxide, Al _{2 O} 3), magnesium oxide (MgO), hafnium oxide _(HfO 2), niobium pentoxide _(NbO 5), titanium oxide _(TiO 2), titanium oxide _(TiO 2), five The tantalum oxide (Ta ₂ O ₅ ) shifts to the longer wavelength side in this order.

Incidentally, the peak wavelength of silicon dioxide (SiO ₂ ) is 4.4 μm, the peak wavelength of alumina (aluminum oxide, Al ₂ O ₃ ) is 4.8 μm, and the peak wavelength of magnesium oxide (MgO) is 4.8 μm. It is 5.1 μm, the peak wavelength of _{hafnium oxide (HfO 2 ) is 5.8 μm, the peak wavelength of niobium pentoxide (NbO 5} ) is 6.2 μm, and the peak wavelength of titanium oxide (TIO ₂ ). Is 6.4 μm, and _{the peak wavelength of tantalum pentoxide (Ta 2} O ₅ ) is 6.5 μm.

[Specific configuration of thermal radiation light source]
As shown in FIG. 8, the thermal radiation light source Q has a substrate adhesion layer S1 between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na. It is laminated, and between the platinum layer P (first platinum layer P1 and second platinum layer P2) and the transparent oxide layer R for resonance in the MIM laminated portion M, and between the transparent oxide layer Nb for radiation and radiation control. The platinum layer S2 is laminated on each of the platinum layer P (second platinum layer P2) adjacent to the radiation transparent oxide layer Nb in the portion Na.

That is, since the substrate adhesion layer S1 is laminated between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na, the radiation control unit Na is on the substrate K. When heated, the radiation control unit Na is prevented from peeling off from the substrate K.

That is, since the coefficient of thermal expansion of the substrate K and the coefficient of thermal expansion of the radiation control unit Na in which a plurality of thin films are laminated are significantly different, when the radiation control unit Na is heated by the substrate K, the radiation control unit Na becomes Although there is a risk of peeling from the substrate K, the adhesion between the substrate K and the platinum layer P (first platinum layer P1) adjacent to the substrate K in the radiation control unit Na is enhanced by the adhesion layer S1 for the substrate. This prevents the radiation control unit Na from peeling off from the substrate K.

Further, the platinum adhesion layer S2 is between the platinum layer P (first platinum layer P1 and second platinum layer P2) and the resonance transparent oxide layer R in the MIM laminated portion M, and the radiation transparent oxide layer. Since it is provided between Nb and the platinum layer P (second platinum layer P2) adjacent to the transparent oxide layer Nb for radiation in the radiation control unit Na, the radiation control unit Na is heated to a high temperature state on the substrate K. At that time, the platinum layer P (first platinum layer P1 and second platinum layer P2) in the MIM laminated portion M is suppressed from flowing and agglomerating, and the platinum layer P and the transparent oxide layer R for resonance are formed. Peeling and peeling of the platinum layer P and the transparent oxide layer Nb for radiation are suppressed.

That is, since the adhesion between platinum and the transparent oxide is low, when the radiation control unit Na is heated to a high temperature state on the substrate K, the platinum layer P adjacent to the transparent oxide layer R for resonance and the transparent for radiation The platinum layer P adjacent to the oxide layer Nb may flow and aggregate, but the platinum layer P adjacent to the transparent oxide layer R for resonance is transparent for resonance due to the lamination of the adhesion layer S2 for platinum. By enhancing the adhesion to the oxide layer R and the adhesion of the platinum layer P adjacent to the radiation transparent oxide layer Nb to the radiation transparent oxide layer Nb, the radiation control unit Na is in a high temperature state on the substrate K. When heated to, the platinum layer P in the MIM laminated portion M is prevented from flowing and aggregating.

As a material for forming the adhesion layer S1 for a substrate and the adhesion layer S2 for platinum, titanium (Ti) and chromium (Cr) are excellent from the viewpoint of melting point and adhesion. In particular, titanium (Ti) is desirable. Hereinafter, it is assumed that the adhesion layer S1 for a substrate and the adhesion layer S2 for platinum are formed of titanium (Ti).

That is, the titanium (Ti) has the adhesion of the platinum layer P (first platinum layer P1) adjacent to the substrate K to the substrate K and the platinum layer P (first platinum layer P1) adjacent to the transparent oxide layer R for resonance. And the adhesion of the second platinum layer P2) to the transparent oxide layer R for resonance and the adhesion of the platinum layer P (second platinum layer P2) adjacent to the transparent oxide layer Nb for radiation to the transparent oxide layer Nb for radiation. Since the properties can be satisfactorily improved and the melting point is as high as 1668 ° C., when the radiation control unit Na is heated to a high temperature state on the substrate K, the platinum layer P (the first) in the MIM laminated unit M. It is possible to appropriately prevent the 1-platinum layer P1 and the 2nd platinum layer P2) from flowing and aggregating.

[Thickness of adhesion layer for substrate]
When the substrate adhesion layer S1 is in a high temperature state, it emits radiant light having a wavelength larger than 4 μm (that is, far infrared light), but the radiant light emitted from the substrate adhesion layer S1 is the first. Since it is shielded by the platinum layer P1, there is no problem even if the thickness (thickness) of the substrate adhesion layer S1 is large in this regard.
However, if the adhesion layer S1 for the substrate is too thick, titanium (Ti) moves around due to heat when the radiation control unit Na is heated to a high temperature state by the substrate K, and the transparent oxide for resonance of the first platinum layer P1. There is a possibility that a phenomenon that appears on the surface of the layer R on the existing side may occur. When such a phenomenon occurs, the thermal radiation control structure of the radiation control unit Na is disrupted, which makes it difficult to control the thermal radiation.

Further, if the adhesion layer S1 for the substrate is too thin, it becomes impossible to cope with the difference between the coefficient of thermal expansion of the radiation control unit Na including the plurality of thin films and the coefficient of thermal expansion of the substrate K, and the radiation control unit Na is in a high temperature state on the substrate K. When heated to, the radiation control unit Na may be peeled off from the substrate K.
From such a viewpoint, the film thickness (titanium film thickness) of the substrate adhesion layer S1 is preferably 2 nm or more and 15 nm or less.

[Thickness of adhesion layer for platinum]
The thickness (film thickness) of the platinum adhesion layer S2 needs to be set from the two viewpoints of opticality and durability.
That is, if the thickness (film thickness) of the platinum adhesion layer S2 is too thick, it is not optically good. That is, when the platinum adhesion layer S2 is in a high temperature state, it emits radiant light having a large wavelength (that is, far infrared light). Therefore, if the platinum adhesion layer S2 is too thick (thickness). , The intensity of the radiant light from the platinum adhesion layer S2 increases, and the radiant light from the radiation control unit Na becomes a small emissivity (emissivity) at a wavelength larger than 8 μm (that is, far infrared light). It has an adverse effect on becoming.

Further, if the thickness (thickness) of the platinum adhesion layer S2 is too thick, radiated light is blocked. Therefore, it is necessary to avoid the platinum adhesion layer S2 being too thick (thickness). ..
However, since the platinum adhesion layer S2 does not adhere the substrate K and the thin film but adheres the thin films to each other, the adhesion effect can be obtained even if it is thinner than the substrate adhesion layer S1.
From this point of view, the thickness (film thickness) of the platinum adhesion layer S2 is preferably 0.1 nm or more and 10 nm or less.

[Oxidation of titanium]
Titanium (Ti) forming the adhesion layer S1 for the substrate and the adhesion layer S2 for platinum is likely to be _{gradually oxidized and changed to titanium oxide (TiO 2) by the use of the thermal radiation light source Q in the atmosphere.} .. In other words, when the thermal radiation light source Q is used in the atmosphere, it can be considered that the adhesion layer S1 for the substrate and the adhesion layer S2 for platinum are formed of _{titanium oxide (TiO 2).} can.

However, as shown in FIG. 9, not all of the titanium forming the platinum adhesion layer S2 is changed to titanium oxide, but the titanium at the portion that adheres to the platinum layer P (second platinum layer P2) is oxidized. The state of titanium (metal state) in close contact with the platinum layer P (second platinum layer P2) is continued without being carried out.
Although not shown, not all of the titanium forming the substrate adhesion layer S1 is changed to titanium oxide, but the titanium at the portion that adheres to the platinum layer P (first platinum layer P1) is oxidized. Instead, the state of titanium (metal state) in close contact with the platinum layer P (first platinum layer P1) is continued.

That is, not all of the titanium forming the substrate adhesion layer S1 and the platinum adhesion layer S2 is changed to titanium oxide, but the titanium at the portion that adheres to the platinum layer P is not oxidized and the platinum layer P is not oxidized. The state of titanium that is in close contact with the titanium will be continued, and the functions as the adhesion layer S1 for the substrate and the adhesion layer S2 for platinum will be continued.

To add an explanation, platinum (Pt) does not react with oxygen because the standard Gibbs energy change is + 200 k / mol / O ₂ (the chemical reaction proceeds in the direction in which the Gibbs energy change becomes negative. A positive energy change means no reaction.) This means that it is difficult to use an oxide as an adhesion layer of platinum (Pt) due to the binding energy. From this, if titanium is changed to titanium oxide by oxidation, there is a concern that it will not work as an adhesion layer of platinum (Pt), but in reality, even if titanium is oxidized, titanium at the interface with platinum (Pt) will not work. Since the bond with platinum is maintained, the functions as the substrate adhesion layer S1 and the platinum adhesion layer S2 will continue.

Incidentally, the adhesion layer S1 for a substrate and the adhesion layer S2 for platinum formed of titanium are formed in a thin film state so as to have light transmission, and the titanium formed in the thin film state is titanium oxide. However, since titanium oxide has transparency, even if titanium is changed to titanium oxide, the performance of the thermal radiation layer N is not adversely affected.
Considering that the materials forming the adhesion layer S1 for the substrate and the adhesion layer S2 for platinum are oxidized, chromium (Cr) becomes black when oxidized. Therefore, chromium which becomes black when oxidized is from the viewpoint of radiation control. _{Titanium (Ti), which forms titanium oxide (TiO 2} ) that is unsuitable as an adhesion layer and becomes transparent when oxidized, is excellent from the viewpoint of radiation control.

By the way, if the titanium (Ti) of the platinum adhesion layer S2 is oxidized over time, even if the platinum adhesion layer S2 is thick, it will eventually become heat radiation when the thickness (film thickness) of FIG. 9 is thin. It is thought that it will approach. However, when the thickness (film thickness) is large, when the radiation control unit Na is heated to a high temperature state on the substrate K, titanium (Ti) moves around due to heat and comes out on the surface of the second platinum layer P2. The phenomenon may occur. When such a phenomenon occurs, the thermal radiation control structure of the radiation control unit Na is disrupted, which makes it difficult to control the thermal radiation. In particular, since the platinum in the second platinum layer P2 is thin, the movement of titanium (Ti) has a great influence on the collapse of the thermal radiation control structure.
Therefore, it is desirable that the thickness (film thickness) of the platinum adhesion layer S2 is about sub nm (about 1 nm or less).

[About the board]
Considering that the thermal radiation of the substrate K, which is in a high temperature state, is shielded by the first platinum layer P1 and does not pass through the radiation control unit Na, the material (base material) of the substrate K is quartz (SiO _2). ), Sapphire, stainless steel (SUS), cantal, nichrome, aluminum, silicon, and various other materials can be used.

There is no particular problem when the substrate K made of an oxide-based material is used, but when the substrate K made of a metal-based material is used, the oxidative deterioration of the substrate K becomes a problem when it is used by heating it in the atmosphere. However, the presence of the transparent oxide layer R for resonance and the transparent oxide layer Nb for radiation prevents oxidative deterioration of the surface of the substrate K on the existence side of the thermal radiation layer N.
The surface of the substrate K on the side where the thermal radiation zone N exists is formed as a mirror surface to the extent that diffuse reflection does not occur.

The substrate K may be configured to self-heat when energized, or may be configured to be heated by the external heating unit U.
That is, when the substrate K is made of a material such as Kanthal or nichrome that generates heat when energized, the substrate K can be configured to self-heat when energized.
When the substrate K is made of quartz (SiO ₂ ), sapphire, stainless steel (SUS) or the like, it is configured to be heated by the external heating unit U as shown in FIGS. 10 to 13. When the substrate K is heated by the external heating unit U, a light absorber (heat absorber) may be provided on the surface of the substrate K facing the external heating unit U.

10 and 11 show a case where the external heating unit U is configured as a plate-shaped heating electrode Ud provided with a heater wire that generates heat when energized, and the substrate K of the thermal radiation light source Q is in close contact with the heating electrode Ud. It is arranged in.
Note that FIG. 11 shows a case where the heat radiant light source Q is arranged on one side of the heating electrode Ud, and FIG. 12 illustrates a case where the heat radiant light source Q is arranged on both sides of the heating electrode Ud. ..

FIG. 12 shows a case where the external heating unit U is configured as a thermal radiation source Ug that emits thermal radiation light G whose wavelength is not controlled, and the substrate K of the thermal radiation light source Q faces the thermal radiation source Ug. It is arranged in a state of being radiant.
FIG. 13 shows a case where the external heating unit U is configured as a fluid supply source Ut for supplying the high temperature fluid T, and the substrate K of the thermal radiation light source Q is arranged so as to face the fluid supply source Ut. There is.

[Another Embodiment]
Hereinafter, another embodiment will be listed.
(1) In the above embodiment, even if the back surface of the substrate K opposite to the surface on which the thermal radiant zone N is laminated is oxidized, if the thickness of the substrate K is thick, the thermal radiant zone N is adversely affected. The back surface of the substrate K opposite to the surface on which the thermal radiation zone N is laminated was exposed, but the back surface is an antioxidant film that suppresses oxidation. May be laminated.

(2) In the above embodiment, the case where the radiation control unit Na includes one MIM laminated unit M is illustrated, but the radiation control unit Na may be implemented in a form including two or more MIM laminated units M. ..
In addition, when a plurality of MIM laminated portions M are provided, three or more platinum layers P arranged along the stacking direction of the thermal radiation layer N and the substrate K are provided, and between adjacent ones in the platinum layer P. , It means a form in which the transparent oxide layer R for resonance is positioned.

The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

K Substrate N Thermal radiation layer Na Radiation control unit Nb Transparent oxide layer for radiation M MIM laminated part P Platinum layer R Transparent oxide layer for resonance S1 Adhesive layer for substrate S2 Adhesive layer for platinum

Claims (7)

A thermal radiant light source in which a thermal radiant layer and a substrate for heating the thermal radiant layer are laminated.
The thermal radiation layer includes a MIM laminated portion in which a transparent oxide layer for resonance formed of a transparent oxide is located between a pair of platinum layers arranged along the stacking direction of the thermal radiation layer and the substrate. The radiation control unit and the radiation transparent oxide layer formed of the transparent oxide are positioned closer to the substrate in this order, and the radiation control unit and the radiation transparent oxide layer are laminated. Configured,
A thermal radiation light source having a thickness of 1200 nm or more and 1500 nm or less, in which a region in which the thickness of the transparent oxide layer for resonance is larger than 4 μm and 8 μm or less is a resonance wavelength region. The thermal radiation light source according to claim 1, wherein an adhesion layer for a substrate is laminated between the substrate and the platinum layer adjacent to the substrate in the radiation control unit. Between the platinum layer and the transparent oxide layer for resonance in the MIM laminated portion, and between the transparent oxide layer for radiation and the platinum layer adjacent to the transparent oxide layer for radiation in the radiation control unit. The thermal radiation light source according to claim 2, wherein an adhesive layer for platinum is laminated on each of the spaces. The thermal radiation light source according to claim 3, wherein the adhesion layer for a substrate and the adhesion layer for platinum are formed of titanium. The thermal radiant light source according to any one of claims 1 to 4, wherein the transparent oxide is aluminum oxide. The thermal radiant light source according to any one of claims 1 to 5, wherein the substrate is configured to self-heat when energized. The thermal radiant light source according to any one of claims 1 to 5, wherein the substrate is heated by an external heating unit.

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