EP3261410A1

EP3261410A1 - Infrared heater

Info

Publication number: EP3261410A1
Application number: EP17161007.4A
Authority: EP
Inventors: Yumi MINEYAMA
Original assignee: Toshiba Lighting and Technology Corp
Current assignee: Toshiba Lighting and Technology Corp
Priority date: 2016-06-24
Filing date: 2017-03-15
Publication date: 2017-12-27
Anticipated expiration: 2037-03-15
Also published as: EP3261410B1; ES2731361T3; JP2017228493A; CN107548171A; JP6834188B2

Abstract

An infrared heater (1) includes a plurality of cylindrical light emitting tubes (5) that emit infrared light, a connection member (6) that connects end portions of the plurality of light emitting tubes (5) arranged along a radial direction of the light emitting tube (5), and a reflecting film (7) that is provided on a peripheral surface of the light emitting tube (5) and that reflects infrared light, in which the reflecting film (7) is formed of a material containing gold as a main component.

Description

FIELD

Embodiments described herein relate generally to an infrared heater.

BACKGROUND

For example, an infrared heater using a halogen lamp or the like is known. In this type of the infrared heater, a configuration, including a reflecting film reflecting infrared light emitted from a light emitting tube in a predetermined irradiation direction, is known. The reflecting film is formed on an outer peripheral surface of the light emitting tube over a predetermined covering range in a circumferential direction. As the reflecting film, a thin film containing alumina or silica as a main component is generally used.
However, the thin film, containing alumina or silica as a main component described above, cannot obtain a reflectivity close to 100% and some of infrared light emitted from the light emitting tube passes through the reflecting film. Therefore, in the irradiation direction of the infrared heater, irradiation efficiency of infrared light is lowered and it is preferable that the reflectivity of the reflecting film is increased.
An object of embodiments is to provide an infrared heater capable of increasing irradiation efficiency of infrared light.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an infrared heater according to an embodiment.
FIG. 2 is a perspective view illustrating the vicinity of a base member.
FIG. 3 is a side view illustrating the infrared heater.
FIG. 4 is a diagram illustrating a relationship between a film thickness of a reflecting film and an irradiation intensity ratio.
FIG. 5 is a view schematically illustrating a modification example of a covering range of the reflecting film.
FIG. 6 is a diagram illustrating a distribution of an irradiation intensity ratio when a center angle formed by an opening portion of the reflecting film is 180°.
FIG. 7 is a diagram illustrating a distribution of the irradiation intensity ratio when the center angle formed by the opening portion of the reflecting film is 160°.
FIG. 8 is a diagram illustrating a distribution of the irradiation intensity ratio if the center angle formed by the opening portion of the reflecting film is 140°.
FIG. 9 is a sectional view illustrating an infrared heater according to another embodiment.
FIG. 10 is a sectional view illustrating an infrared heater according to a modification example of the other embodiment.

DETAILED DESCRIPTION

An infrared heater according to an embodiment described below includes a plurality of light emitting tubes that emit infrared light, a connection member, and a reflecting film. The light emitting tube has a cylindrical shape. The plurality of light emitting tubes are arranged along a radial direction of the light emitting tube. The connection member connects end portions of the plurality of light emitting tubes arranged along the radial direction of the light emitting tube. The reflecting film is provided on a peripheral surface of the light emitting tube and reflects infrared light. The reflecting film is formed of a material containing gold as a main component.
In addition, in the infrared heater according to the embodiment described below, the reflecting film is provided over a covering range of 1/4 or more and 3/4 or less of an entire circumference of the light emitting tube.
In addition, in the infrared heater according to the embodiment described below, a film thickness of the reflecting film is 45 [nm] or more and 300 [nm] or less.
In addition, in the infrared heater according to the embodiment described below, in each of the light emitting tubes that are positioned on both sides in an arrangement direction of the plurality of light emitting tubes, the reflecting film is disposed to be offset toward a side opposite to an adjacent light emitting tube with respect to a center line of the light emitting tube orthogonal to the arrangement direction in a cross section orthogonal to a length direction of the light emitting tube.
In addition, in the infrared heater according to the embodiment described below, the plurality of light emitting tubes include at least three light emitting tubes. In the light emitting tube that is positioned at a center in the arrangement direction of the plurality of light emitting tubes, the reflecting film is disposed symmetrically with respect to the center line of the light emitting tube, orthogonal to the arrangement direction in the cross section orthogonal to the length direction of the light emitting tube.

Embodiments

Hereinafter, an infrared heater according to an embodiment will be described with reference to the drawings. FIG. 1 is a plan view illustrating the infrared heater according to the embodiment. FIG. 2 is a perspective view illustrating the vicinity of a base member included in the infrared heater according to the embodiment. FIG. 3 is a side view illustrating the infrared heater according to the embodiment.
An infrared heater 1 according to the embodiment includes a plurality of light emitting tubes 5 emitting infrared light, a base member 6 as a connection member, and a reflecting film 7. The infrared heater 1 is configured of a so-called halogen heater. Hereinafter, the infrared heater 1 having two light emitting tubes 5 is described, but the number of the light emitting tubes 5 is not limited. In the infrared heater 1, as illustrated in FIGS. 1, 2, and 3, an arrangement direction of the plurality of light emitting tubes 5 is defined as an X direction, a length direction of the light emitting tube 5 is defined as a Y direction, and a direction, in which the light emitting tube 5 faces an object (not illustrated) to be irradiated with infrared light, is defined as a Z direction.
The light emitting tube 5 is formed in a cylindrical shape with, for example, quartz glass. A filament 11 formed of, for example, tungsten is provided on an inside of the light emitting tube 5 along the length direction of the light emitting tube 5. The filament 11 may be formed of a material containing kanthal or carbon as a component. The filament 11 formed of the material described above is provided so that the infrared heater 1 can emit infrared light from a short wavelength band to a middle wavelength band.
A plurality of ring-shaped anchors 12, which support the filament 11, are disposed on the inside of the light emitting tube 5 at intervals in the length direction of the light emitting tube 5. The filament 11 is supported at predetermined positions in the radial direction in the light emitting tube 5 through the anchors 12.
Both ends of the filament 11 are elongated in the length direction of the light emitting tube 5 and are joined to one end portion of a metal foil 14, but the both ends of the filament 11 are not limited to those that are elongated, and for example, the both ends of the filament 11 may be linearly formed. A lead wire 15 is joined to the other end portion of the metal foil 14 and the lead wire 15 is drawn out from the light emitting tube 5. Sealing portions 16 that cover the metal foils 14 are formed at the both end portions of the light emitting tube 5. The sealing portion 16 is formed as a so-called pinch seal formed in a flat plate shape, but it may be formed as a so-called shrink seal formed in a cylindrical shape. In FIGS. 2 and 3, the flat plate shaped sealing portions 16 are provided side by side along the arrangement direction (X direction) of the plurality of light emitting tubes 5, but the orientation of the flat plate shaped sealing portions 16 is not limited, and, for example, the flat plate shaped sealing portions 16 may be disposed along the Z direction.
Therefore, the plurality of light emitting tubes 5 are arranged in parallel each other along the radial direction (X direction) of the light emitting tube 5. The light emitting tubes 5 are connected, for example, in parallel respectively via the lead wires 15, but it is not limited to parallel connection, and may be connected in series.
In addition, as illustrated in FIGS. 1 and 3, among the plurality of light emitting tubes 5, a gap D between adjacent light emitting tubes 5 in the arrangement direction (X direction) of the plurality of light emitting tubes 5 is set to 10 [mm] or less in a light emitting region A of the light emitting tube 5. From the viewpoint of suppressing a decrease in an irradiation intensity ratio due to the gap D, it is preferable that the gap D is reduced and it may be a state where outer peripheral surfaces of the adjacent light emitting tubes 5 are in contact with each other, that is, the gap D may be 0 [mm]. If the gap D exceeds 10 [mm], it is undesirable because the irradiation intensity ratio decreases due to the gap D.
The base members 6 connect the sealing portions 16 at the both end portions of the plurality of light emitting tubes 5 arranged along the radial direction of the light emitting tube 5. The base member 6 is formed of, for example, a heat-resistant resin material, ceramics, or the like, and is fixed to the sealing portion 16 by adhesive. The base member 6 has a plurality of holding portions 6a holding the sealing portions 16 of each light emitting tube 5. The holding portion 6a has holding grooves 6b that sandwiches the sealing portion 16 of the light emitting tube 5. In addition, the lead wire 15 drawn from the sealing portion 16 of the light emitting tube 5 passes through the base member 6, and the lead wire 15 is drawn out from the base member 6 to an outside of the infrared heater 1. The light emitting tube 5 is supplied with power from an external power supply (not illustrated) via the lead wire 15, and the light emitting tube 5 emits infrared light.
The reflecting film 7 is provided on an outer peripheral surface as a peripheral surface of the light emitting tube 5, and the reflecting film 7 reflects infrared light, emitted by the light emitting tube 5, in a predetermined irradiation direction. Moreover, the reflecting film 7 may be provided on an inner peripheral surface of the light emitting tube 5. The reflecting film 7 is formed of a material containing gold as a main component and a reflectivity thereof is higher than that of a reflecting film formed of a material containing alumina, silica, or the like as a main component.
As illustrated in FIG. 3, the reflecting film 7 is provided over a predetermined covering range in the circumferential direction of the light emitting tube 5 and, as illustrated in FIG. 1, is provided over the light emitting region A in the length direction (Y direction) of the light emitting tube 5. As the predetermined covering range, as illustrated in FIG. 3, the reflecting film 7 is provided over a covering range of 1/4 or more and 3/4 or less of an entire circumference of the light emitting tube 5 in the circumferential direction. In other words, the reflecting film 7 is provided over a covering range in which a center angle around a center axis O of the light emitting tube 5 is 90° or more and 270° or less. As an example, the reflecting film 7 illustrated in FIG. 3 is provided over a covering range of 1/2(180°) in the circumferential direction of the light emitting tube 5.
In addition, as illustrated in FIG. 3, the position of the reflecting film 7 in the circumferential direction of each light emitting tube 5 is provided on a side opposite to a side facing the object to be irradiated. In each light emitting tube 5, the reflecting film 7 is disposed symmetrically with respect to a center line C1 of the light emitting tube 5 orthogonal to the arrangement direction (X direction) of the plurality of light emitting tubes 5 in a cross section (X-Z plane) orthogonal to the length direction (Y direction) of the light emitting tube 5. Therefore, each reflecting film 7 of each light emitting tube 5 is also provided symmetrically with respect to a center line C2 in the arrangement direction of the plurality of light emitting tubes 5 in the cross section (X-Z plane). Moreover, although each modification example of the covering range of the reflecting film 7 will be described later, in the circumferential direction of the light emitting tube 5, the reflecting film 7 may be disposed to be offset toward one side with respect to the center line C1 of the light emitting tube 5.

Film Thickness of Reflecting Film

FIG. 4 is a diagram illustrating a relationship between a film thickness of the reflecting film 7 included in the infrared heater 1 according to the embodiment and an irradiation intensity ratio. In FIG. 4, a vertical axis indicates the irradiation intensity ratio [%] and a horizontal axis indicates the film thickness [nm] of the reflecting film 7. The irradiation intensity ratio [%] in FIG. 4 is illustrated as 100 [%] as a reference value if there is no reflecting film 7 in the light emitting tube 5 and indicates a ratio of a change in an irradiation intensity with respect to the reference value if a film thickness of the reflecting film 7 provided in the light emitting tube 5 is changed.
As illustrated in FIG. 4, in the reflecting film 7, the irradiation intensity ratio increases as the film thickness increases, and if the film thickness is approximately 130 [nm] or more, an increase in the reflectivity, that is, an increase in the irradiation intensity ratio becomes gentle, and the irradiation intensity ratio substantially tends to be almost stabilized. In the reflecting film 7, if the film thickness is approximately 180 [nm] or more, an increase in the irradiation intensity ratio peaks and even if the increase in the irradiation intensity ratio is 300 [nm] or more, the irradiation intensity ratio does not substantially change. Therefore, in FIG. 4, in the film thickness of the reflecting film 7, data from 0 [nm] to 240 [nm] is illustrated and data from 240 [nm] to 300 [nm], and data exceeding 300 [nm] are omitted. In addition, the reflecting film 7 becomes easier to peel off as the film thickness becomes thicker and a cost of a raw material increases as a using amount of gold increases. On the other hand, if the film thickness of the reflecting film 7 is less than 45 [nm], an amount of transmission of infrared light transmitted through the reflecting film 7 is large and a sufficient reflectivity cannot be obtained.
In consideration of such a trade-off relationship, the film thickness of the reflecting film 7 in the embodiment is set to 45 [nm] or more and 300 [nm] or less. In addition, it is preferable that the film thickness of the reflecting film 7 is, for example, within a range of approximately 90 [nm] or more and approximately 230 [nm] or less if improvement of the irradiation intensity, suppression of peeling of the reflecting film 7, and suppression of an increase in the cost of the raw material are appropriately ensured.

Covering Range of Reflecting Film

FIG. 5 is a view schematically illustrating a modification example of the covering range of the reflecting film 7 included in the infrared heater 1 according to the embodiment. Here, for the sake of convenience of description, a non-covering range in which the reflecting film 7 is not provided, which is positioned between both ends of the reflecting film 7 in the circumferential direction of the light emitting tube 5, is referred to as an opening portion of the reflecting film 7. In FIG. 5, an angle θ1 formed by the both ends of the reflecting film 7 in the circumferential direction of the light emitting tube 5 around the center axis O of the light emitting tube 5 is referred to as a center angle θ1 formed by the opening portion of the reflecting film 7, and each modification example, in which the center angle θ1 is changed to 180°, 160°, and 140°, is illustrated vertically in line.
In FIG. 5, when the center angle θ1 formed by the opening portion of the reflecting film 7 is 180°, an inclined angle θ2, in which a plane connecting the both ends of the reflecting film 7 is inclined around the center axis O of the light emitting tube 5, is referred to as an inclined angle θ2 of an opening surface of the reflecting film 7, and each modification example, in which the inclined angle θ2 is changed to 0°, 15°, 30°, and 45°, is illustrated horizontally in line. In addition, in each modification example in which the inclined angle θ2 is changed, each reflecting film 7 of two light emitting tubes 5 is inclined symmetrically with respect to the center line C2 in the arrangement direction of the two light emitting tubes 5.
Even if the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and 140°, similar to a case where the center angle θ1 is 180°, each modification example, in which the inclined angle θ2 is changed to 0°, 15°, 30°, and 45°, is illustrated horizontally in line. Moreover, if the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and 140°, in the cross section (X-Z plane) of the light emitting tube 5 orthogonal to the center axis O (length direction) of the light emitting tube 5, the inclined angle θ2, in which a line segment connecting one end of the reflecting film 7 and the center axis O of the light emitting tube 5 in the circumferential direction of the light emitting tube 5 is inclined around the center axis O, corresponds to the inclined angle θ2 of the opening surface of the reflecting film 7.
In FIG. 5, a configuration, in which the center angle θ1 formed by the opening portion of the reflecting film 7 is 180°, corresponds to a configuration, in which the reflecting film 7 is formed over a covering range of the center angle 180° around the center axis O. A configuration, in which the center angle formed by the opening portion of the reflecting film 7 is 160°, corresponds to a configuration, in which the reflecting film 7 is formed over a covering range of a center angle 200° around the center axis O. A configuration, in which the center angle formed by the opening portion of the reflecting film 7 is 140°, corresponds to a configuration, in which the reflecting film 7 is formed over a covering range of a center angle 220° around the center axis O.
As illustrated in FIG. 5, in the covering range of the reflecting film 7, the center angle θ1 and the inclined angle θ2 may be appropriately changed as necessary for adjusting light distribution characteristics and is not limited to the angle of one example described above. It is possible to increase an irradiation amount of infrared light irradiated in a direction facing the opening portion of the reflecting film 7 in an arbitrary radial direction of the light emitting tube 5 by changing the center angle θ1 and the inclined angle θ2.

Relationship Between Covering Range of Reflecting Film And Irradiation Intensity Ratio

FIG. 6 is a diagram illustrating a distribution of the irradiation intensity ratio if the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° in the infrared heater 1 according to the embodiment. FIG. 7 is a diagram illustrating a distribution of the irradiation intensity ratio if the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° in the infrared heater 1 according to the embodiment. FIG. 8 is a diagram illustrating a distribution of the irradiation intensity ratio if the center angle θ1 formed by the opening portion of the reflecting film 7 is 140° in the infrared heater 1 according to the embodiment.
In FIGS. 6, 7, and 8, a vertical axis indicates the irradiation intensity ratio [%] and a horizontal axis indicates a distance [mm] from the center line C2 in the arrangement direction (X direction) of two light emitting tubes 5. FIGS. 6, 7, and 8 are results of measuring the distribution of the irradiation intensity ratio of infrared light irradiated from the two light emitting tubes 5 in each modification example (example) illustrated in FIG. 5. Here, the irradiation intensity ratio is illustrated as 100 [%] as a reference value of the irradiation intensity if the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° and the inclined angle θ2 is 0°, and indicates a ratio of the irradiation intensity with respect to the reference value. For the infrared heater 1 having the light emitting tubes 5 of each example, a measurement of the irradiation intensity was performed by using a multipurpose spectral radiometer MSR-7000 (manufactured by Opto Research Co., Ltd), disposing a photodetector on the center line C2 in the arrangement direction of the two light emitting tubes 5, and setting a distance between the light emitting tube 5 and the photodetector in the Z direction to 30 [mm].
In FIG. 6, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° and the inclined angle θ2 is 0°, is indicated by a solid line as Example 1 (180°, 0°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° and the inclined angle θ2 is 15°, is indicated by a broken line as Example 2 (180°, 15°). In addition, in FIG. 6, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° and the inclined angle θ2 is 30°, is indicated by a one-dotted chain line as Example 3 (180°, 30°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 180° and the inclined angle θ2 is 45°, is indicated by a dotted line as Example 4 (180°, 45°).
As illustrated in FIG. 6, if the center angle θ1 formed by the opening portion of the reflecting film 7 is 180°, as the inclined angle θ2 increased, the irradiation intensity ratio of the center line C2 in the arrangement direction of the two light emitting tubes 5 was gradually increased and the irradiation intensity ratio at a position separated from the center line C2 in the arrangement direction decreased.
Similarly, in FIG. 7, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and the inclined angle θ2 is 0°, is indicated by a two-dotted chain line as Example 5 (160°, 0°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and the inclined angle θ2 is 15°, is indicated by a broken line as Example 6 (160°, 15°). In addition, in FIG. 7, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and the inclined angle θ2 is 30°, is indicated by a one-dotted chain line as Example 7 (160°, 30°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 160° and the inclined angle θ2 is 45°, is indicated by a dotted line as Example 8 (160°, 45°). In addition, also in FIG. 7, Example 1 (180°, 0°) is indicated by a solid line.
Similar to a case where the center angle θ1 is 180°, as illustrated in FIG. 7, also if the center angle θ1 formed by the opening portion of the reflecting film 7 is 160°, as the inclined angle θ2 increased, the irradiation intensity ratio of the center line C2 in the arrangement direction of the two light emitting tubes 5 was gradually increased and the irradiation intensity ratio at a position separated from the center line C2 in the arrangement direction decreased. In addition, in Example 5 (160°, 0°), the irradiation intensity ratio in the arrangement direction was increased more than that of a case of Example 1 (180°, 0°).
In addition, similarly, in FIG. 8, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 140° and the inclined angle θ2 is 0°, is indicated by a two-dotted chain line as Example 9 (140°, 0°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 140° and the inclined angle θ2 is 15°, is indicated by a broken line as Example 10 (140°, 15°). In addition, in FIG. 8, a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 140° and the inclined angle θ2 is 30°, is indicated by a one-dotted chain line as Example 11 (140°, 30°) and a case, where the center angle θ1 formed by the opening portion of the reflecting film 7 is 140° and the inclined angle θ2 is 45°, is indicated by a dotted line as Example 12 (140°, 45°). In addition, also in FIG. 8, Example 1 (180°, 0°) is indicated by a solid line.
Similar to a case where the center angle θ1 is 180°, as illustrated in FIG. 8, also if the center angle θ1 formed by the opening portion of the reflecting film 7 is 140°, as the inclined angle θ2 increased, the irradiation intensity ratio of the center line C2 in the arrangement direction of the two light emitting tubes 5 was gradually increased and the irradiation intensity ratio at a position separated from the center line C2 in the arrangement direction decreased. In addition, in Example 9 (140°, 0°), the irradiation intensity ratio in the arrangement direction was increased more than that of a case of Example 1 (180°, 0°).
In addition, as illustrated in FIGS. 6, 7, and 8, as the center angle θ1 formed by the opening portion of the reflecting film 7 decreased, that is, the covering range of the reflecting film 7 in the circumferential direction of the light emitting tube 5 increased, the irradiation intensity ratio in the vicinity of the center line C2 in the arrangement direction of the two light emitting tubes 5 gradually increased. This is because the center angle θ1 formed by the opening portion of the reflecting film 7 decreases and thereby infrared light, emitted from each light emitting tube 5, is collected, in the configuration having the two light emitting tubes 5. In addition, in the configuration having the two light emitting tubes 5, this is because the inclined angle θ2, in which the reflecting film 7 is inclined around the center axis O symmetrically with respect to the center line C2, increases and thereby infrared light, emitted from each light emitting tube 5, is collected toward the center line C2 in the arrangement direction of the two light emitting tubes 5.
As described above, the infrared heater 1 of the embodiment has the reflecting film 7 formed of a material containing gold as a main component. Therefore, infrared light, passing through the reflecting film 7 from the light emitting tube 5, is suppressed and the reflectivity of the reflecting film 7 is increased. Therefore, it is possible to increase irradiation efficiency of infrared light. In addition, the infrared heater 1 has the base member 6. Therefore, arbitrary number of light emitting tubes 5 can be connected at a desired gap D and a degree of freedom for adjusting light distribution characteristics is increased.
In addition, the reflecting film 7 included in the infrared heater 1 is provided over a covering range of 1/4 or more and 3/4 or less of an entire circumference of the light emitting tube 5. Therefore, the irradiation intensity is appropriately adjusted according to the covering range of the reflecting film 7 and desired light distribution characteristics can be obtained. In addition, the position of the reflecting film 7 in the circumferential direction of the light emitting tube 5 is appropriately adjusted. Therefore, the irradiation intensity ratio is appropriately adjusted in the arrangement direction of the plurality of light emitting tubes 5 and desired light distribution characteristics can be obtained.
In addition, the film thickness of the reflecting film 7 included in the infrared heater 1 is 45 [nm] or more and 300 [nm] or less. Therefore, improvement of the irradiation intensity, suppression of peeling of the reflecting film 7, and suppression of an increase in the cost of the raw material can be appropriately ensured.
In addition, in the infrared heater 1, among the plurality of light emitting tubes 5, the gap D between adjacent light emitting tubes 5 in the arrangement direction of the plurality of light emitting tubes 5 is 10 [mm] or less in the light emitting region A of the light emitting tube 5. Therefore, it is possible to reduce the gap, in which the irradiation of infrared light is reduced, between adjacent light emitting tubes 5, to suppress occurrence of variation in the distribution of the irradiation intensity in the arrangement direction of the plurality of light emitting tubes 5, and to obtain desired light distribution characteristics in the arrangement direction.
Hereinafter, an infrared heater of other embodiments will be described with reference to the drawings. Moreover, in the other embodiments, the same reference numerals are given to the same configuration members as those in the embodiment described above and description thereof will be omitted.

Other Embodiments

FIG. 9 is a sectional view illustrating an infrared heater according to another embodiment. FIG. 10 is a sectional view illustrating an infrared heater according to a modification example of the other embodiment. The other embodiments are different from the embodiment described above in that three light emitting tubes 5 are arranged.
As illustrated in FIG. 9, an infrared heater 2 of the other embodiment includes a base member 26 connecting each sealing portion 16 of both ends of the three light emitting tubes 5 arranged in a radial direction of a light emitting tube 5. The reflecting film 7 is provided over a covering range of 1/2 (180°) in a circumferential direction of the light emitting tube 5 on the outer peripheral surface of each light emitting tube 5. In addition, a position of the reflecting film 7 in the circumferential direction of the light emitting tube 5, is positioned on a side opposite to a side facing an object to be irradiated and is disposed symmetrically with respect to a center line C1 of the light emitting tube 5, orthogonal to an arrangement direction (X direction) of the three light emitting tubes 5 in a cross section orthogonal to a length direction (Y direction) of the light emitting tube 5.
As illustrated in FIG. 10, in an infrared heater 3 of a modification example of the other embodiment, in each light emitting tube 5 positioned at both sides in an arrangement direction (X direction) of three light emitting tubes 5, the reflecting film 7 is disposed so as to offset toward a side opposite to adjacent light emitting tube 5 with respect to center lines C1 of the light emitting tubes 5, orthogonal to the arrangement direction in a cross section (X-Z plane) orthogonal to length directions of the light emitting tubes 5. That is, the reflecting film 7 of each light emitting tube 5 positioned at both sides in the arrangement direction of the three light emitting tubes 5, is offset so that the opening portion, that is, a center region of the reflecting film 7 in the circumferential direction of the light emitting tube 5 faces on a center line C2 side in the arrangement direction. Therefore, the light emitting tube 5 can increase the irradiation amount irradiated with infrared light in a direction facing a side in which the reflecting film 7 is disposed so as to offset. In addition, each reflecting film 7 of each light emitting tube 5 positioned at both sides in the arrangement direction of the three light emitting tubes 5, is provided symmetrically with respect to the center line C2 in the arrangement direction in the cross section (X-Z plane) orthogonal to the length direction of the light emitting tube 5.
In addition, in one light emitting tube 5 positioned at the center in the arrangement direction of the three light emitting tubes 5, the reflecting film 7 is disposed symmetrically with respect to the center line C1 of the light emitting tube 5, orthogonal to the arrangement direction in the cross section (X-Z plane) orthogonal to the length direction of the light emitting tube 5. Moreover, for example, in a case of a configuration having six light emitting tubes 5, the light emitting tube 5, positioned at the center in the arrangement direction of the six light emitting tubes 5, includes two light emitting tubes 5. That is, in a case of a configuration having the odd number of the light emitting tubes 5, one light emitting tube 5 is positioned at the center in the arrangement direction of the plurality of light emitting tubes 5 and in a case of a configuration having the even number of the light emitting tubes 5, two light emitting tube 5 are positioned at the center in the arrangement direction of the plurality of light emitting tubes 5.
According to the infrared heater 2 of the other embodiment, the light emitting tube 5, in which reflection efficiency is enhanced by the reflecting film 7, is increased. Therefore, an irradiation range of infrared light can be expanded. Therefore, the distribution of the irradiation intensity ratio in the arrangement direction of the three light emitting tubes 5 is adjusted and desired light distribution characteristics can be obtained.
In addition, according to the infrared heater 3 of the modification example of the other embodiment, light is collected at the center that is the center line C2 side in the arrangement direction by the reflecting film 7 of two light emitting tubes 5 positioned on both sides in the arrangement direction of the three light emitting tubes 5, and the irradiation intensity ratio of the center can be increased. Therefore, the center in the arrangement direction of the three light emitting tubes 5, can be irradiated with a narrowed irradiation range and the object to be irradiated, disposed at a position facing the center line C2 in the arrangement direction, can be efficiently heated.
Moreover, a configuration, in which the disposition of the reflecting films 7 in the circumferential direction of the light emitting tube 5, or the covering range of the reflecting film 7 in the circumferential direction of the light emitting tube 5 is gradually changed from the light emitting tube 5 of the center in the arrangement direction of the plurality of light emitting tubes 5 toward each light emitting tube 5 at the both ends in the arrangement direction, may be provided. In the arrangement direction of the plurality of light emitting tubes 5, the disposition or the covering range of the reflecting films 7 is changed. Therefore, the distribution of the irradiation intensity ratio in the arrangement direction can be easily adjusted and desired light distribution characteristics can be obtained.
For example, in a case of a configuration having five light emitting tubes 5, in the arrangement direction of the five light emitting tubes 5, the covering range of each reflecting film 7 of two light emitting tubes 5 positioned at the both ends, one light emitting tube 5 positioned at the center, and two light emitting tubes 5 adjacent to each of the light emitting tubes 5 of the both ends, may be different in the circumferential direction of each light emitting tube 5. For example, the reflecting film 7 may gradually increase an offset amount toward both sides in the arrangement direction of the plurality of light emitting tubes 5 as going from the light emitting tube 5 of the center to the light emitting tubes 5 of the both ends, and it is possible to collect light toward the center side in the arrangement direction.
Otherwise, the covering range of the reflecting film 7 may be varied according to the position of each light emitting tube 5 in the arrangement direction so that the irradiation distribution in the arrangement direction of the plurality of light emitting tubes 5 becomes uniform. In addition, the reflecting film 7 is not limited to the configuration in which the reflecting films 7 are provided all the plurality of light emitting tubes 5. In the plurality of light emitting tubes 5, the light emitting tube 5, in which another reflecting film having reflectivity different from that of the reflecting film 7 formed of gold is provided, may be included, or a light emitting tube 5, in which the reflecting film 7 is not provided, may be included as necessary for adjusting light distribution characteristics.
In addition, as the reflecting film provided in one light emitting tube 5, the reflecting film 7 formed of gold and a reflecting film formed of alumina or silica may be used in combination in the circumferential direction of one light emitting tube 5. In this case, in one light emitting tube 5, a configuration, in which a ratio of each reflecting film of a plurality of types having different reflectivity is changed in the arrangement direction of the plurality of light emitting tubes 5, may be provided. In addition, the reflecting film 7 may be formed so that the covering range in the circumferential direction is gradually changed between the both sides and the center in the length direction (direction of the center line C1) of one light emitting tube 5. For example, in each light emitting tube 5, the covering range of the reflecting films 7 at the both ends in the length direction (Y direction), increases more than the covering range of the reflecting film 7 of the center in the length direction. Therefore, the irradiation distribution, generated in the length direction of the light emitting tube 5, may be appropriately adjusted.
In addition, in the infrared heater 1 of the embodiment, although the plurality of light emitting tubes 5 are aligned and arranged in a line, the position of each light emitting tube 5 may be disposed different in the length direction (Y direction) of the light emitting tube 5 or the direction (Z direction) facing the object to be irradiated in the arrangement direction (X direction) of the plurality of light emitting tubes 5 as necessary for adjusting desired light distribution characteristics.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

An infrared heater comprising:
a plurality of cylindrical light emitting tubes that emit infrared light;

a connection member that connects end portions of the plurality of light emitting tubes disposed along a radial direction of the light emitting tube; and

a reflecting film that is provided on a peripheral surface of the light emitting tube and that reflects infrared light,

wherein the reflecting film is formed of a material containing gold as a main component.
The heater according to claim 1,
wherein the reflecting film is provided over a covering range of 1/4 or more and 3/4 or less of an entire circumference of the light emitting tube.
The heater according to claim 1 or 2,
wherein a film thickness of the reflecting film is 45 [nm] or more and 300 [nm] or less.
The heater according to any one of claims 1 to 3,
wherein in each of the light emitting tubes that are positioned on both sides in an arrangement direction of the plurality of light emitting tubes, the reflecting film is disposed to be offset toward a side opposite to an adjacent light emitting tube with respect to a center line of the light emitting tube, orthogonal to the arrangement direction in a cross section orthogonal to a length direction of the light emitting tube.
The heater according to claim 4,
wherein the plurality of light emitting tubes include at least three light emitting tubes, and
in the light emitting tube that is positioned at a center in the arrangement direction of the plurality of light emitting tubes, the reflecting film is disposed symmetrically with respect to the center line of the light emitting tube, orthogonal to the arrangement direction in the cross section orthogonal to the length direction of the light emitting tube.