JP7124593B2 - heater - Google Patents

Description

Embodiments of the present invention relate to heaters.

Conventionally, it is known to use, for example, a heater as a heat source. It is known that the heater has a reflective film that reflects the light emitted from the arc tube in a predetermined irradiation direction.

Also, it is known that the reflective film uses alumina or gold as a material. A reflective film using alumina has excellent heat resistance, and a reflective film using gold has excellent reflective properties.

JP 2015-197959 A

However, with conventional reflective films, it has been difficult to improve both the light reflection efficiency and the heat resistance of the reflective film.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heater capable of enhancing both the reflection efficiency and heat resistance of a reflective film.

A heater according to an embodiment includes an arc tube, a first reflective film, and a second reflective film. The arc tube is cylindrical and transmits light. The first reflective film is provided on the outer surface of the arc tube and reflects light to the inside of the arc tube. The second reflective film is provided so as to cover the first reflective film, and has a lower light reflectance than the first reflective film.

According to the present invention, both the reflection efficiency and heat resistance of the reflective film can be enhanced.

It is a side view of a heater concerning an embodiment. It is a top view of a heater concerning an embodiment. It is a sectional view of a heater concerning an embodiment. FIG. 4 is a diagram comparing reflectances of heaters; It is the figure which compared the surface temperature of a reflective film. FIG. 10 is a diagram comparing reflectance for each wavelength;

A heater 1 according to an embodiment described below includes an arc tube 21 , a first reflective film 5 and a second reflective film 6 . The arc tube 21 is cylindrical and transmits light. The first reflective film 5 is provided on the outer surface 2 b of the arc tube 21 and reflects light to the inside of the arc tube 21 . The second reflective film 6 is provided so as to cover the first reflective film 5 and has a lower light reflectance than the first reflective film 5 .

Further, the first reflective film 5 according to the embodiment described below contains a metal as a main component, and the second reflective film 6 contains an inorganic compound as a main component.

Also, the thickness of the second reflective film 6 according to the embodiment described below is greater than the thickness of the first reflective film 5 .

Embodiments according to the present invention will be described below with reference to the drawings. It should be noted that the embodiments shown below do not limit the technology disclosed by the present invention. In addition, the embodiments and modifications described below can be appropriately combined within a consistent range. In addition, in the description of the embodiments, the same reference numerals are given to the same configurations, and the description later will be omitted as appropriate.

[Embodiment]
An embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a side view showing a heater according to an embodiment; FIG. FIG. 2 is a cross-sectional view showing the heater according to the embodiment. FIG. 3 is a cross-sectional view of the heater according to the embodiment. In addition, FIG. 1 is a diagram in which a part of the heater 1 in the tube axis direction is omitted. FIG. 2 is a further simplified diagram of the heater 1. As shown in FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. In order to make the explanation easier to understand, FIG. 1 shows a three-dimensional orthogonal coordinate system including the Z-axis in which the light irradiation direction of the heater 1 is the negative direction. Such an orthogonal coordinate system may also be shown in other drawings used in the following description.

The heater 1 according to the embodiment provides heat to an object to be irradiated or a space to be irradiated. It is envisioned for use in irradiation equipment that The heater 1, as shown in FIG. is composed of The heater 1 has a lamp power of 1500W to 2500W.

The bulb 2 transmits internal light to the outside, and includes a cylindrical portion 21 and seal portions 22 and 23 . The bulb 2 is made of, for example, quartz glass, is transparent and uncolored, and is long and has a long overall length compared to the diameter of the tube.

The tubular portion 21 has an interior 2a as an internal space, and the filament 3 is arranged in the interior 2a. The tubular portion 21 is an example of an arc tube.

The seal portions 22 and 23 are arranged at both end portions of the cylindrical portion 21 in the pipe axis direction. The seal portions 22 and 23 are sealing portions and seal the cylindrical portion 21 . The seal portions 22 and 23 in this embodiment are formed in a plate shape by pinch seal. In addition, the seal portions 22 and 23 may be formed in a cylindrical shape by shrink sealing.

The filament 3 is arranged along the tube axis inside 2a of the bulb 2, and a main portion 31, leg portions 32 and 33, and an anchor 34 are integrally formed. The filament 3 in this embodiment is a metal wire made of tungsten.

The main portion 31 is a portion that generates heat and emits light when lit, and is arranged inside the bulb 2 . The main portion 31 is formed by winding a metal wire. As shown in FIG. 3, the main portion 31 is formed in a circular shape when viewed from the tube axis direction. That is, the main portion 31 is formed in a cylindrical shape.

The leg portions 32 and 33 are arranged at both end portions of the main portion 31 in the pipe axis direction, and are partially embedded in the seal portions 22 and 23 . The leg portions 32 and 33 are portions that supply power to the main portion 31 . One ends of the leg portions 32 and 33 are connected to both ends of the main portion 31, respectively, and the other ends are electrically connected to the metal foils 61 and 62, respectively.

The anchor 34 is a support member for the main portion 31 and is configured as a separate member from the main portion 31 and the leg portions 32 and 33 . The anchor 34 is connected to the main portion 31 by winding several turns around the main portion 31 at one end. The anchor 34 is formed so that its central portion faces the inner wall 2 c of the valve 2 . The other end of the anchor 34 is formed in an arc shape along the inner wall 2c when viewed from the pipe axis direction. One or more anchors 34 are provided in the tube axial direction so as to maintain a predetermined pitch, and support the main portion 31 of the filament 3 so as to be positioned substantially in the center of the interior 2 a of the bulb 2 .

A gas 4 fills the interior 2 a of the valve 2 . The gas 4 in this embodiment is argon gas of about 0.8 atm containing a small amount of dibromomethane (CH ₂ Br ₂ ). The gas 4 preferably has a low thermal conductivity. Specifically, the gas 4 may contain one of krypton, xenon, argon, neon, or the like, or a combination of two or more of them. Further, it may contain one kind of halogen substance such as bromine and iodine, or a combination of two or more kinds thereof.

A first reflective film 5 is formed on the outer surface 2 b of the bulb 2 . The first reflective film 5 is formed in the region of the cylindrical portion 21 of the outer surface 2b. The first reflective film 5 is formed in an arc shape along the outer surface 2b when viewed from the tube axis direction. The first reflective film 5 reflects the light from the filament 3 toward the inside 2a of the bulb 2. As shown in FIG. In other words, the first reflective film 5 reflects part of the light that passes through the bulb 2 from the filament 3 and is irradiated to the outside of the bulb 2 toward the inside 2 a of the bulb 2 . The region where the first reflecting film 5 covers the outer surface 2b of the bulb 2 when viewed from the tube axis direction is determined arbitrarily. The area where the first reflective film 5 covers the outer surface 2b of the bulb 2 in the heater 1 having the bulb 2 in a linear shape forms an angle with respect to the axis O of the bulb 2, that is, the angle θ1 in the circumferential direction of the bulb 2 is 170° to 170°. 230° is preferred. The film angle of the first reflective film 5 in this embodiment is 180°.

Further, the width L2 of the first reflecting film 5 in the tube axis direction can satisfy L2≧L1, where L1 is the total length of the main portion 31 in the tube axis direction. By defining the width L2 of the first reflective film 5 in this manner, the reflection efficiency of the light emitted from the main portion 31 can be enhanced throughout the tube axis direction. Note that the width L2 of the first reflective film 5 is arbitrarily determined so as to have irradiation characteristics according to requirements, and may be L2<L1, for example.

The first reflective film 5 is made mainly of a metal containing gold or silver. Specifically, the first reflective film 5 is made of a metal material in which 50% or more of all components are gold or silver. The first reflective film 5 has higher reflection efficiency than the second reflective film 6 .

The second reflective film 6 is formed so as to cover the outside of the first reflective film 5 . The second reflective film 6 has higher heat resistance than the first reflective film 5 and reinforces the first reflective film 5 . In addition, the first reflective film 5 promotes the heat dissipation of the second reflective film 6, and can suppress, for example, deterioration of reflection characteristics due to aggregation due to overheating. Here, the thickness of the second reflective film 6 can be made larger than the thickness of the first reflective film 5 . By defining the thickness of the second reflective film 6 in this way, the heat dissipation of the first reflective film 5 can be further enhanced.

Further, in the area where the second reflecting film 6 covers the first reflecting film 5, the angle formed with respect to the axial center O of the bulb 2, that is, the angle θ2 in the circumferential direction of the bulb 2 is preferably θ1 or more, for example, 0. °≦(θ2−θ1)≦10°. Further, the width L3 of the second reflecting film 6 in the tube axis direction can satisfy L3≧L2 with respect to the width L2 of the first reflecting film 5 . By defining the angle θ2 and the width L3 of the second reflecting film 6 in this manner, the heat resistance of the first reflecting film 5 can be enhanced over the entire circumferential direction and the tube axis direction.

The second reflective film 6 is made of a material containing an inorganic compound as a main component. Specifically, 50% or more of all components of the second reflective film 6 are inorganic compounds. Inorganic compounds include, for example, alumina (Al ₂ O ₃ ), silica (SiO ₂ ) or barium sulfate (BaSO ₄ ).

When the second reflective film 6 contains alumina as a main component, it may contain titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ). As a result, the average particle size of the particles contained in the second reflective film 6 can be reduced, so that the physical strength of the second reflective film 6 can be enhanced.

The metal foils 61 and 62 have one end connected to the leg portions 32 and 33 of the filament 3 and the other end connected to the outer leads 71 and 72 . The metal foils 61 and 62 are embedded inside the seal portions 22 and 23, respectively. The metal foils 61 and 62 in this embodiment are molybdenum foils and are arranged along the plate-like surfaces of the seal portions 22 and 23 .

The outer leads 71, 72 connect the metal foils 61, 62 to an external power source (not shown). One ends of the outer leads 71 and 72 are connected to the metal foils 61 and 62 , respectively, and the other ends are exposed to the outside of the bulb 2 . Parts of the outer leads 71 and 72 are embedded in the seal portions 22 and 23, respectively. The other ends of the outer leads 71 and 72 are inserted into connectors (not shown) together with the seal portions 22 and 23, respectively, electrically connected to a cable (not shown) provided in the connector, and connected to a power source through the cable. . The outer leads 71, 72 are molybdenum rods.

Next, with reference to FIGS. 4 to 6, differences in reflection characteristics, surface temperature, and spectral distribution depending on the presence or absence of the second reflection film 6 will be described. FIG. 4 is a diagram comparing reflectances of heaters. FIG. 5 is a diagram comparing the surface temperatures of the reflective films. FIG. 6 is a diagram comparing spectral distributions for each wavelength. In FIGS. 4 to 6, a heater prototype using gold (Au) as the material of the first reflective film 5 and alumina (Al ₂ O ₃ ) as the material of the second reflective film 6 is referred to as a "second reflective film." A prototype of a heater having only the first reflective film 5 without forming the second reflective film 6 was produced and evaluated as ``without the second reflective film''. In FIG. 4, a handy spectral color difference meter NF 777 (manufactured by Nippon Denshoku Industries Co., Ltd.) was used as a measuring device. In FIG. 6, a multi-purpose spectroradiometer MSR-7000 (manufactured by Opto Research Co., Ltd.) was used as a measuring device.

First, the irradiation characteristics of the heater will be described with reference to FIG. The horizontal axis of FIG. 4 indicates the lighting load. The lighting conditions are as follows. First, after lighting at 3.5 W/mm, lighting is performed for a certain period of time at the desired lighting load (W/mm) (3.5, 4, 5, 6, 7, 8) shown on the horizontal axis, and then at 3.5 W/mm. mm. The desired lighting load is shown on the horizontal axis, and the relative reflection intensity is shown on the vertical axis. The relative reflection intensity is a value obtained by standardizing the reflectance after re-lighting, with the reflectance when the light is first lit at 3.5 W/mm under lighting conditions being 100%.

As shown in FIG. 4, in the case of "no second reflective film", the first reflective film 5 deteriorates at a lighting load of 5 W/mm or more, and the reflectance decreases. On the other hand, in the case of "with the second reflective film", even if the lighting load is 8 W/mm, the reflectance does not decrease, and it can be seen that a metallic reflective film can be used even with a high-load heater.

Further, as shown in FIG. 5, in the case of "with the second reflecting film", the heat capacity of the entire reflecting film increases, so that the film surface temperature is lower than in the case of "without the second reflecting film". Therefore, deterioration of the first reflective film 5 is unlikely to occur even under high load.

Next, the spectral distribution of the heater will be described with reference to FIG. The horizontal axis of FIG. 6 indicates wavelength, and the vertical axis indicates intensity. The intensity is a value obtained by normalizing the intensity with the peak illuminance without the second reflective film as 100%. As shown in FIG. 6, in the case of “with the second reflective film”, the peak value in the infrared region was higher than in the case of “without the second reflective film”, and the irradiation intensity increased by about 5% at maximum. .

As described above, the heater 1 according to the embodiment includes the arc tube 21, the first reflective film 5, and the second reflective film 6. As shown in FIG. The arc tube 21 is cylindrical and transmits light. The first reflective film 5 is provided on the outer surface of the arc tube 21 and reflects light to the inside of the arc tube 21 . The second reflective film 6 is provided so as to cover the first reflective film 5 and has a lower light reflectance than the first reflective film 5 . Thereby, both the reflection efficiency and the heat resistance of the reflection film can be improved.

Further, the first reflective film 5 according to the embodiment contains metal as a main component, and the second reflective film 6 contains an inorganic compound as a main component. Thereby, both the reflection efficiency and the heat resistance of the reflection film can be improved.

Also, the thickness of the second reflective film 6 according to the embodiment is greater than the thickness of the first reflective film 5 . Thereby, the heat resistance of the reflective film can be further improved.

In addition, although the heater 1 according to the above-described embodiment is formed in a straight line, the shape is not limited to this. The heater 1 may be curved.

While embodiments of the invention have been described, the embodiments are provided by way of example and are not intended to limit the scope of the invention. Embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. The embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and its equivalents.

REFERENCE SIGNS LIST 1 heater 2 bulb 2b outer surface 3 filament 4 gas 5 first reflective film 6 second reflective film

Claims (6)

a cylindrical arc tube that transmits light;
a first reflective film provided on the outer surface of the arc tube for reflecting the light to the inside of the arc tube;
a second reflecting film provided to cover the first reflecting film and having a lower reflectance of the light than the first reflecting film;
and
an angle θ1 of the first reflective film in the circumferential direction of the arc tube;
The angle θ2 of the second reflective film in the circumferential direction is
A heater having a relationship of θ1<θ2 . The angle θ1 and the angle θ2 are
2. The heater according to claim 1, having a relationship of 0°<(θ2−θ1)≦10°. a width L2 of the first reflective film in the tube axis direction of the arc tube;
The width L3 of the second reflecting film in the tube axis direction is
3. A heater according to claim 1 or 2, having a relationship of L3>L2. The heater according to any one of claims 1 to 3 , wherein said first reflective film contains metal as a main component, and said second reflective film contains an inorganic compound as a main component. The second reflective film contains alumina as a main component and titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ). 6. The heater according to claim 1, wherein the thickness of said second reflective film is greater than the thickness of said first reflective film.

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