Filament lamp

Abstract

To provide a filament lamp with an excellent life time by suppressing a short circuit of a filament even in the case where the filament is extended to a pipe shaft direction.SOLUTION: A filament lamp comprises: a light emission pipe in which a power supply part is formed to a first end part side; a filament that includes a plurality of coil parts and a coupling part, and to which each coil part and the coupling part between a pair of power supply parts are alternately connected; a support member that is fixed to a second end part side of the light emission pipe; a fixing part that is supported by the support member; and a supporter that engages a folding part with the coupling part of the filament in a state of being supported by the support member, where a first part connecting the folding part, a one end part of the folding part, and the fixing part and a second part that is extended from the other end part of the folding part. In the first and second parts, a shape that is separated from the pipe shaft of the light emission pipe as far from the filament or a separation distance from a pipe shaft has a constant shape.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a filament lamp for heating. [Background technology]

[0002] 2. Description of the Related Art Conventionally, single-ended filament lamps have been widely used as point-light-source type heat sources in optical heating devices for heat-treating semiconductor wafers (see Patent Document 1 below).

[0003] In optical heating devices, a large amount of heating light (hereinafter simply referred to as "heating light") is required to raise the temperature of the wafer to a high temperature of, for example, 1000°C or more. For this reason, filament lamps are used in which the filament is provided with multiple coil sections and the multiple coil sections are arranged around the axis of the light-emitting tube to increase the heat radiation from the filament. For example, as shown in Patent Document 2 below, in filament lamps, a supporter is arranged that engages with a section that connects the multiple coil sections (hereinafter simply referred to as the "connecting section"), and the supporter holds the filament within the light-emitting tube.

[0004] Furthermore, in optical heating devices, from the viewpoint of making it easier to uniform the temperature within the wafer surface, multiple single-ended type filament lamps are arranged opposite the peripheral edge of the wafer, which requires more heating light than the center. In other words, in such optical heating devices, the tube axis of the filament lamps is arranged parallel to the main surface of the wafer (see also Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 2945661 [Patent Document 2] JP 2002-56817 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a light heating device in which the tube axis of the filament lamp is arranged parallel to the main surface of the wafer, a large amount of heating light travels to the opposite side of the wafer, resulting in poor efficiency of the light heating device.

[0007] Therefore, from the viewpoint of directing as much heating light as possible toward the wafer, a reflector that reflects the heating light is installed on the opposite side of the filament lamp from the wafer. However, some of the light reflected by the reflector (hereinafter simply referred to as "reflected light") is blocked by the filament lamp before it is irradiated onto the wafer, making it difficult for the reflected light to be irradiated onto the wafer. For this reason, optical heating devices in which the filament lamp is positioned perpendicular to the main surface of the wafer are being considered.

[0008] By arranging a single-ended type filament lamp perpendicular to the main surface of the wafer, it becomes possible to arrange a reflector that reflects the heating light around the light emitting tube of the filament lamp. As a result, the reflected light absorbed by the filament lamp is reduced compared to when the filament lamp is arranged parallel to the main surface of the wafer, and it is expected that the efficiency of the optical heating device will be improved.

[0009] In a light heating device, the direction perpendicular to the main surface of the wafer is typically the vertical direction. In light of this, the inventors of the present invention considered lighting a filament lamp with its tube axis oriented vertically, and discovered that multiple coils arranged inside the light emitting tube would come into contact with each other and be prone to short-circuiting.

[0010] Fig. 14 is a cross-sectional view showing a schematic view of part of the structure of a conventional filament lamp 51, as typified by Patent Document 2. Fig. 14 shows the location where the supporter 50 fixed to the support member 4a engages with the filament 3. Fig. 14 also shows an XYZ coordinate system in which the direction in which the tube axis A1 of the arc tube 2 extends is the Z direction, and the plane perpendicular to the Z direction is the XY plane. As shown in Fig. 14, in the filament lamp 51, the supporter 50 engages with the connecting portion 11 of the filament 3 to hold the filament 3.

[0011] Filament lamps have the property that when the filament 3 inside the light emitting tube 2 becomes hot, the wire that makes up the filament 3 softens and stretches under its own weight. For this reason, if the filament lamp 51 is positioned so that the +Z direction corresponds to the vertical downward direction, the filament 3 stretches in the +Z direction.

[0012] In other words, when the filament 3 extends in the +Z direction while the connecting portion 11 of the filament 3 is held by the supporter 50, the connecting portion 11 moves along the supporter 50. For this reason, the present inventors have inferred that the multiple coil portions 10 are deformed so as to approach each other, which makes the filament 3 more likely to short-circuit.

[0013] In a filament lamp, for example, a tungsten filament evaporates when turned on, or wears down due to repeated temperature increases and decreases, eventually breaking at a certain point and reaching the end of its life (natural lifespan). However, if the filament shorts out, the lifespan of the filament lamp will be shortened. This is because, for example, if the coil part of the filament shorts out, the resistance value of the filament decreases, causing a large current to flow, which significantly increases the temperature of the filament and causes it to melt. In other words, from the perspective of extending the lifespan of a filament lamp, it is essential to prevent filament shorts.

[0014] In view of the above circumstances, an object of the present invention is to provide a filament lamp in which short circuits of the filament are suppressed and which has an excellent life span even when the filament is stretched in the axial direction of the tube. [Means for solving the problem]

[0015] The filament lamp according to the present invention comprises: a light emitting tube having a pair of power supply parts formed on a first end side; a filament having a plurality of coil portions and at least one connecting portion, the coil portions and the connecting portions being alternately connected between the pair of power supply portions; a support member fixed to a second end side of the arc tube opposite to the first end side; a supporter having a fixed portion supported by the supporting member, a bent portion, a first portion connecting one end of the bent portion and the fixed portion, and a second portion extending from the other end of the bent portion, the bent portion engaging with the connecting portion of the filament when supported by the supporting member, The first and second portions are characterized in that they are shaped so that they move away from the axis of the light-emitting tube as they move away from the filament, or are shaped so that the distance between them and the axis is constant.

[0016] As a result of extensive research, the inventors have found that when the filament expands in the tube axial direction during lighting, the connecting portion of the filament that engages with the supporter moves along the supporter, as described above with reference to Fig. 14. In other words, depending on the shape of the supporter, the filament deforms so that the multiple coil portions arranged inside the light-emitting tube approach each other, causing the coil portions to come into contact with each other and short-circuit.

[0017] In contrast, in the above configuration, the first and second parts of the supporter are shaped to move away from the tube axis of the light-emitting tube as they move away from the filament. As a result, even if the filament extends in the tube axis direction and the connecting part of the filament moves along the supporter, the multiple coil parts deform to move away from each other, thereby preventing a short circuit of the filament.

[0018] Furthermore, in the case where the first and second portions of the supporter have a shape in which the distance between them and the axis of the arc tube is constant, even if the filament connection portion moves along the supporter as described above, the coil portions are prevented from approaching each other. In other words, with the above configuration, short-circuiting between the coil portions due to deformation of the filament is prevented.

[0019] In the above filament lamp, the first portion and the second portion may be linear.

[0020] Here, "straight line" means that when viewing a target line connecting two points and a virtual line connecting the two points in the shortest distance, the amount of displacement of the target line relative to the virtual line in a direction perpendicular to the virtual line is within 10% of the length of the virtual line.

[0021] If the coil portion were to bend when the filament stretches and the connecting portion moves along the supporter, the coil portions would approach each other, making the filament more susceptible to short-circuiting. In contrast, with the above configuration, the filament moves more smoothly along the first or second portion of the supporter when the filament is deformed. In other words, the smooth movement of the filament over the supporter prevents the coil portions from bending when the filament stretches, making the above configuration preferable.

[0022] In the filament lamp, The first and second portions have a shape that moves away from the tube axis of the light-emitting tube as it moves away from the filament, and if the angle between the first portion and the tube axis is θ1, θ1 may be set to satisfy the following formula (1). 0°<θ1≦30° (1)

[0023] The above-mentioned configuration provides a filament lamp with a longer lifespan, as will be described in detail later in the section entitled "Description of the Preferred Embodiments of the Invention."

[0024] In the above filament lamp, The second portion is disposed at a position farther from the tube axis than the first portion, When the angle between the first portion and the tube axis is θ1 and the angle between the second portion and the tube axis is θ2, θ1 and θ2 may satisfy the following formula (2). θ1<θ2 (2)

[0025] According to the above configuration, when the filament is elongated in the tube axis direction, it is likely to move along the second portion disposed on the outer side of the first portion, which makes it easier to deform the filament so that the coil portion moves outward, and therefore the above configuration is preferable.

[0026] In the above filament lamp, The second portion may have a length in the tube axis direction of an extending portion from the bent portion that is equal to or greater than ¼ of a length of the coil portion.

[0027] The details will be described in the verification section below, but according to the above configuration, a filament lamp with a long life can be realized with a simpler configuration. The length of the extension part of the second part from the bent part will be explained for each embodiment with reference to the drawings.

[0028] The supporter may also have a third portion extending from an end of the second portion opposite the bent portion and in contact with the first portion. Effect of the Invention

[0029] According to the present invention, even if the filament is stretched in the tube axial direction, short circuits of the filament are suppressed, and a filament lamp having an excellent life span is provided. [Brief description of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view showing a schematic diagram of one embodiment of a filament lamp. [Diagram 2]2 is a cross-sectional view of the filament lamp in FIG. 1 as viewed in the Y direction. [Diagram 3] FIG. 2 is a plan view showing a schematic structure of a filament provided in a filament lamp. [Figure 4] 2 is an enlarged view of the +Z side of the arc tube of FIG. 1. [Diagram 5] 5 is an enlarged view of the supporter in FIG. 4. [Figure 6] 13 is a diagram showing another example of the configuration of the supporter. [Figure 7] 1 is a diagram showing the definition of positive and negative of angle θ1 in Verification 1. [Figure 8A] 5 is a diagram showing a schematic diagram of a case where the filament is stretched in the +Z direction from the state shown in FIG. 4. [Figure 8B] 15 is a diagram showing a schematic diagram of a case where the filament is extended in the +Z direction from the state of FIG. 14, following FIG. 8A. [Figure 9] 11 is a diagram illustrating a schematic structure of a supporter when a first portion and a second portion are parallel to a tube axis. [Figure 10] 6 is a diagram showing a schematic diagram of another example of the configuration of the supporter in accordance with FIG. 5. [Figure 11A] 13 is a diagram showing yet another configuration example of the supporter. [Figure 11B] 11B is an enlarged view of the supporter of FIG. 11A. [Figure 12A] 11 is a view showing another example of the configuration of the supporter in accordance with FIG. 10. [Figure 12B] 12B is an enlarged view of the supporter of FIG. 12A. [Figure 13A] 13 is a diagram showing yet another configuration example of the supporter. [Figure 13B] 13B is an enlarged view of the supporter of FIG. 13A. [Figure 14] FIG. 1 is a cross-sectional view showing a schematic view of a portion of the structure of a conventional filament lamp. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] An embodiment of a filament lamp according to the present invention will be described with reference to the drawings. Note that the following drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios. Furthermore, the dimensional ratios between the drawings do not necessarily match.

[0032] In addition, in the following figures, as in Fig. 14, explanations will be given with appropriate reference to an XYZ coordinate system in which the axial direction of the light emitting tube of the filament lamp is the Z direction and the plane perpendicular to the Z direction is the XY plane. Fig. 1 is a cross-sectional view showing a schematic representation of one embodiment of a filament lamp, and Fig. 2 is a cross-sectional view of the filament lamp of Fig. 1 as viewed in the Y direction. Also, Fig. 3 is a plan view showing a schematic representation of the structure of a filament provided in a filament lamp.

[0033] In the following description, when a positive or negative direction is to be distinguished from a positive or negative direction, the direction is described with a positive or negative sign, such as "+X direction" and "-X direction". When a direction is to be described without distinguishing between positive and negative directions, the direction is simply described as "X direction". In other words, in this specification, when the direction is simply described as "X direction", both the "+X direction" and the "-X direction" are included. The same applies to the Y direction and the Z direction.

[0034] As shown in FIG. 1, the filament lamp 1 includes an arc tube 2, a filament 3, supporting members (4a, 4b), supporters (5a, 5b), and a base .

[0035] The arc tube 2 is made of a glass material such as quartz glass, and has a sealing portion 9 at an end 30 on the -Z side and an exhaust tube remaining portion 13 at an end 31 on the +Z side. The sealing portion 9 has a flat shape when viewed from the X direction (see FIG. 1). In this embodiment, the end 30 corresponds to the "first end" and the end 31 corresponds to the "second end". The internal space of the arc tube 2 is filled with a halogen gas such as iodine, bromine, or chlorine, together with an inert gas such as nitrogen or argon.

[0036] As an example, the inner diameter of the arc tube 2 is 2.5 cm, and the overall length of the arc tube 2, that is, the distance between the end 30 and the end 31 in the Z direction, is 10.5 cm.

[0037] A pair of metal foils (7a, 7b) are embedded in the sealing portion 9 of the light-emitting tube 2 to form the power supply portion 6. The metal foils (7a, 7b) are made of a metal material such as molybdenum.

[0038] The arc tube 2 also includes a pair of internal leads (8a, 8b) in the internal space. One end of the internal lead 8a is wound around and connected to the end 3a of the filament 3, and the other end is connected to the metal foil 7a. One end of the internal lead 8b is wound around and connected to the end 3b of the filament 3, and the other end is connected to the metal foil 7b.

[0039] The base 14 is made of an insulating material such as alumina, and has a bottomed hole (not shown) on the +Z side into which the sealing part 9 of the arc tube 2 is inserted. By inserting the sealing part 9 into this bottomed hole, the base 14 and the arc tube 2 are fixed together. As shown in Figs. 1 and 2, a terminal 15 for supplying power to the filament 3 protrudes from the -Z side of the base 14. The terminals 15 are provided in a pair, and by connecting each terminal 15 to the metal foils (7a, 7b), power is supplied to the filament 3 from the outside via the terminals 15. In other words, the filament lamp 1 is a single-ended type having a pair of terminals 15 on the -Z side.

[0040] As shown in Fig. 3, the filament 3 is formed by alternately forming a plurality of coil portions 10 and connecting portions 11 that connect the coil portions 10. The filament 3 is formed by winding a wire made of tungsten, for example. Note that, for convenience of illustration, the number of coil portions 10 is omitted in Fig. 3, but in this embodiment, a filament 3 having eight coil portions 10 is housed in the light emitting tube 2.

[0041] In a single-end type filament lamp used in a light heating device, the length L1 of the coil portion 10 of the filament 3 is typically set to 20 mm to 26 mm. In this embodiment, as an example, the length L1 of the coil portion 10 of the filament 3 is set to 24 mm.

[0042] The support member 4a is fixed to the end 31 side of the arc tube 2 (see Figs. 1 and 2). Fig. 4 is an enlarged view of the end 31 side of the arc tube 2 in Fig. 1. As shown in Fig. 4, a supporter 5a and a support rod 12 are embedded in the support member 4a.

[0043] 1 and 2, in this embodiment, a support member 4b is fixed to the end portion 30 side of the light emitting tube 2. A pair of internal leads (8a, 8b), a supporter 5b, and a support rod 12 are embedded in the support member 4b.

[0044] The support members (4a, 4b) are made of a glass material such as quartz glass. For example, the supporter 5a and the support rod 12 are inserted into the support member 4a which is in a heated and molten state, and then the support member 4a is cooled and solidified, so that the supporter 5a and the support rod 12 can be embedded in the support member 4a. An insulating material is selected for the support member 4a so that the supporter 5a and the support rod 12 are not electrically connected to each other. The same applies to the support member 4b.

[0045] The support members (4a, 4b) may have any shape, but as an example, a cylindrical shape as shown in Figs. 1 and 2 may be adopted.

[0046] One end of the support rod 12 is disposed in the remaining exhaust pipe portion 13 (see FIG. 1). The support members (4a, 4b) are fixed within the arc tube 2 by the support rod 12.

[0047] Fig. 5 is an enlarged view of the supporter 5a in Fig. 4, excluding the illustration of the filament 3, etc. As shown in Fig. 5, the supporter 5a has a fixed portion 20 supported by the support member 4a, a bent portion 24, a first portion 21 connecting one end of the bent portion 24 to the fixed portion 20, and a second portion 22 extending from the other end of the bent portion 24, and is U-shaped. The bent portion 24 engages with the connecting portion 11 of the filament 3.

[0048] More specifically, the fixing portion 20 corresponds to a portion of the supporter 5a that is supported by the support member 4a. The second portion 22 of this embodiment corresponds to a portion of the supporter 5a that extends from a portion located on the -Z side toward an end portion farthest from the tube axis A1. The first portion 21 corresponds to a portion between the fixing portion 20 and the second portion 22 of the supporter 5a that moves away from the tube axis A1 as it moves toward the +Z side. The bent portion 24 corresponds to a position between the first portion 21 and the second portion 22 of the supporter 5a.

[0049] The bent portions 24 engage with the connecting portions 11 of the filament 3, so that the winding axes of the coil portions 10 are arranged substantially parallel to the tube axis A1 of the light emitting tube 2. Note that "substantially parallel" means that the angle between the winding axis of the coil portion 10 and the tube axis A1 is within 5°.

[0050] In this embodiment, the fixed portion 20 has a shape extending in a direction parallel to the XY plane.

[0051] 5, the first portion 21 and the second portion 22 have a shape that moves away from the tube axis A1 of the light-emitting tube 2 as they move away from the filament 3. The first portion 21 having the above shape means that the angle θ1 between the first portion 21 and the tube axis A1 is greater than 0°.

[0052] In this embodiment, the first portion 21 and the second portion 22 are configured to be parallel to each other. That is, in this embodiment, the angle θ2 (see also FIG. 10 described later) between the second portion 22 of the supporter 5a and the tube axis A1 is equal to the angle θ1.

[0053] 5 also illustrates lengths d1 and d2. Length d1 corresponds to the length in the Z direction of first portion 21. Length d2 corresponds to the length in the Z direction of an extension portion of second portion 22 from bent portion 24. In this embodiment, length d2 is 6 mm.

[0054] As mentioned above, when the filament 3 expands during lighting of the filament lamp 1, the filament 3 moves along the first portion 21 and the second portion 22. For this reason, it is easy to imagine that if the length d2 is too short, the filament 3 will come off the supporter 5a. Details will be described later in the section "Verification 2," but it is preferable that the length d2 be ¼ or more of the length L1 of the coil portion 10.

[0055] The filament lamp 1 according to this embodiment has a supporter 5b that is disposed on the -Z side of the filament 3 and engages with the connecting portion 11 of the filament 3. Like the supporter 5a, the supporter 5b is shaped so that it moves away from the tube axis A1 as the first portion 21 and the second portion 22 move away from the filament 3.

[0056] The supporters (5a, 5b) are made of a metal wire such as tungsten.

[0057] Fig. 6 is a diagram showing another example of the configuration of the supporter 5a. Fig. 4 shows an example in which the fixing portion 20 of the supporter 5a is parallel to the XY plane, but as shown in Fig. 6, the fixing portion 20 may be non-parallel to the XY plane. Also, as shown in Fig. 6, the second portion 22 may be disposed adjacent to the inner wall surface of the arc tube 2.

[0058] [Verification 1] The effect that the structure of the supporter 5a has on the lifespan of the filament lamp 1 has been examined and will be explained below.

[0059] In this verification, filament lamps were produced in which the angle θ1 between the first portion 21 of the supporter 5a and the tube axis A1 was varied, and the lifespan of each filament lamp was tested. Note that in this verification, as a comparative example, a case was also verified in which the supporter 5a has a shape that approaches the tube axis A1 the further it is from the filament 3, as described with reference to Figure 14.

[0060] FIG. 7 is a diagram showing the definition of positive and negative of the angle θ1 in this verification. Specifically, in this verification, as shown in FIG. 7, when a virtual line B1 that passes through the connection part of the first part 21 of the supporter 5a and the bent part 24 and is parallel to the tube axis A1 is used as a reference, θ1 is defined as having a positive value when the first part 21 is inclined away from the tube axis A1 with respect to the virtual line B1. On the other hand, for convenience, θ1 is defined as having a negative value when the supporter 5a is inclined toward the virtual line B1 from the tube axis A1. That is, in FIG. 7, the direction moving toward the direction C1 with respect to the virtual line B1 corresponds to the positive direction of θ1, and the direction moving toward the direction C2 with respect to the virtual line B1 corresponds to the negative direction of θ1. In this verification, the case where θ1 is a negative value corresponds to the comparative example (see also FIG. 14).

[0061] In this verification, the filament lamp configuration according to the embodiment described above was adopted, except that the angle θ1 was made different for each filament lamp. Also, the filament lamps were arranged so that the Z direction corresponded to the vertical downward direction.

[0062] In an optical heating device, for example, the voltage applied to the filament lamp is repeatedly increased and decreased in order to set the temperature condition of the wafer to the desired temperature. Therefore, in this verification, an operation was performed in which the filament lamp was repeatedly switched between a first state in which the desired brightness was obtained from the filament lamp, and a second state in which the brightness was obtained below a certain threshold value, in accordance with the lighting operation of an actual optical heating device.

[0063] As mentioned above, the life of a filament lamp comes to an end when the filament 3 breaks. This includes natural lifespans caused by evaporation and wear of the filament, and lifespans caused by a short circuit in the coil section 10. In light of this, in this verification, the above-mentioned operation was repeated, and the time until the filament 3 broke was evaluated as the lifespan of the filament lamp.

[0064] In this verification, three filament lamps were tested for each θ1 condition.

[0065] [Results and Considerations of Test 1] The results obtained in this experiment are shown in Table 1. In Table 1, the average value of the lifespan of the filament lamp obtained for each θ1 is shown.

[0066] [Table 1]

[0067] From Table 1, it can be seen that the lifespan of a filament lamp is affected by the angle θ1. This is because when the filament 3 expands in the tube axis direction during lighting, the connecting part 11 of the filament 3 that engages with the supporter 5a moves along the supporter 5a.

[0068] Furthermore, the inventors have observed that when θ1 is a negative value, the filament 3 is deformed by lighting, resulting in a short circuit of the multiple coil portions 10 of the filament 3. On the other hand, when the angle θ1 is in the range of 0° or more, no short circuit of the multiple coil portions 10 was observed even if the filament 3 was deformed by lighting.

[0069] This point will be described with reference to Figures 8A and 8B. Figure 8A is a diagram that shows a schematic diagram of a state in which the filament 3 becomes hotter and deforms so as to extend in the +Z direction from the state shown in Figure 4. Figure 8B is a diagram that shows a schematic diagram of a state in which the filament 3 becomes hotter and deforms so as to extend in the +Z direction from the state shown in Figure 14, following Figure 8A.

[0070] As shown in FIG. 8A, in the case where the first portion 21 is shaped to move away from the tube axis A1 as it moves away from the filament 3, the connecting portion 11 of the filament 3 moves along the first portion 21 or the second portion 22, and as a result, the coil portion 10 moves so as to move away from the other coil portions 10. More specifically, in the example shown in FIG. 8A, even if the filament 3 extends in the +Z direction, the multiple coil portions 10 on the +Y side of the tube axis A1 move away from the multiple coil portions 10 on the -Y side of the tube axis A1. This prevents the multiple coil portions 10 from contacting each other and causing a short circuit in the filament 3. In FIG. 8A, the movement direction of the coil portion 10 is typically indicated by a double arrow A2.

[0071] On the other hand, as shown in FIG. 8B, when the supporter 5a is shaped to approach the tube axis A1 as it moves away from the filament 3, the connecting portion 11 of the filament 3 moves along the supporter 5a, and as a result, the coil portion 10 approaches the tube axis A1. As a result, the coil portions 10 are more likely to come into contact with each other, causing the filament 3 to short-circuit. This is consistent with the fact that the lifespan becomes shorter as θ1 increases in the negative direction in Table 1. In other words, when θ1 increases in the negative direction, a short circuit between the coil portions occurs more quickly.

[0072] Also, Fig. 9 is a diagram showing a schematic structure of the supporter 5a when the first portion 21 and the second portion 22 have a shape with a constant distance from the tube axis A1. That is, the example of Fig. 9 corresponds to the case where θ1 in this verification 1 is 0°. As shown in Fig. 9, when the first portion 21 and the second portion 22 are parallel to the tube axis A1, it is considered that the filament 3 extends in the +Z direction, and as a result, the connecting portion 11 also moves in the +Z direction. In other words, even in this case, the coil portions 10 of the filament 3 are prevented from approaching each other. It is considered that this has made the life of the filament lamp longer than the case described with reference to Fig. 8B (Table 1).

[0073] In this way, it can be seen that by making the angle θ1 0° or more, even if the filament 3 is deformed so as to expand in the +Z direction, the multiple coil portions 10 are less likely to approach each other. In other words, by making the angle θ1 0° or more, short circuits in the filament 3 are suppressed, and the life of the filament lamp is extended (Table 1).

[0074] Incidentally, it is preferable to set the angle θ1 to a positive value from the viewpoint of reducing the possibility of shorting out the filament 3. This can also be understood from the fact that the life of the filament lamp is longer when θ1 is 15° or 30° than when θ1 is 0°.

[0075] In addition, when θ1 is set to 45°, the life is shorter than when θ1 is set to 30°. In view of this, it is presumed that as θ1 increases, the stress applied to the filament 3 increases when the filament 3 is significantly deformed along the supporter 5a. In view of the above, it is more preferable that θ1 is set to 0°<θ1≦30°.

[0076] In addition, in view of the results of this verification, it can be understood that θ1 may be different for each supporter 5a within the arc tube 2.

[0077] In addition, it is optional whether the first portion 21 and the second portion 22 of the supporter 5a are parallel to each other. Fig. 10 is a diagram showing a schematic diagram of another configuration example of the supporter 5a following Fig. 5. As shown in Fig. 10, the angle θ2 between the second portion 22 and the tube axis A1 and the angle θ1 between the first portion 21 and the tube axis A1 may be different, and the supporter 5a may be V-shaped.

[0078] In view of the results of this verification, the same discussion as for θ1 can be made about the angle θ2 between the second portion 22 and the tube axis A1. In other words, it is preferable that the angle θ2 is 0° or more, and more preferably 0°<θ2≦30°. Furthermore, as shown in FIG. 10, if θ1<θ2, it becomes easier to deform the filament 3 along the second portion 22, which is preferable.

[0079] In view of the results of Verification 1 above, it can be seen that by configuring the supporter 5a as described in the above embodiment, a filament lamp with an excellent life span can be realized.

[0080] [Verification 2] As described above, if the length d2 of the second portion 22 is too short, it is easily assumed that the filament 3 will come off the supporter 5a when the filament 3 is stretched. If the engagement between the filament 3 and the supporter 5a comes off, it becomes difficult to control the position of the filament 3 inside the arc tube 2, and the filament 3 will easily come into contact with another filament 3 and short-circuit. In view of this, it is considered preferable that the end of the second portion 22 is close to the inner wall surface of the arc tube 2, as described with reference to Fig. 6. In other words, according to the configuration of Fig. 6, even if the connecting portion 11 of the filament 3 moves along the second portion 22, the movement of the filament 3 is restricted by the inner wall of the arc tube 2, and the filament 3 is prevented from coming off the supporter 5a.

[0081] However, if the supporter 5a and the inner wall of the arc tube 2 are placed close to each other, there is a high possibility that the inner wall surface of the arc tube 2 will be scratched when the supporter 5a is placed inside the arc tube 2. In order to avoid such scratches, great care must be taken when manufacturing the filament lamp 1. If there are scratches on the inner wall surface of the arc tube 2, the thermal stress caused by the rise in temperature due to light emission will concentrate, increasing the risk of the arc tube 2 cracking. Therefore, for example, the configuration shown in Figure 6 is highly likely to make it difficult to manufacture the filament lamp 1.

[0082] In view of the above, it would be preferable to be able to more simply configure the supporter 5a that is less likely to come loose from the filament 3 even if the filament 3 stretches in the Z direction. In view of this, the inventors produced filament lamps in which the length d2 (see FIG. 5) of the extension portion from the bent portion 24 of the second portion 22 in the supporter 5a was varied, and lit each filament lamp following the above verification 1. They then considered the preferred length d2 for preventing the connection portion 11 of the filament 3 from coming loose from the supporter 5a.

[0083] In this verification, filament lamps were produced with different lengths d2, with the length L1 of the coil portion 10 set to 24 mm, and lighting tests were conducted following the above verification 1. In addition, in light of the results of the above verification 1, θ1 was set to 30° in this verification. The other conditions of the filament lamp were the same as in verification 1.

[0084] [Results and Considerations of Verification 2] The evaluation results of the filament lamps under each d2 condition are shown in Table 2. The evaluation criteria in Table 2 are as follows: Evaluation (A): No loss of filament 3 was observed. Evaluation (B): The percentage of filament lamps in which the filament 3 has come off the supporter 5a (hereinafter, for convenience, referred to as the "fall-off percentage") is 10% or less of the total number of samples. Rating (C): Dropout rate is 50% or more

[0085] [Table 2]

[0086] According to Table 2, it can be seen that the detachment of the filament 3 from the supporter 5a can be suppressed if the length d2 is 6 mm or more, that is, if the length d2 is 1 / 4 or more of the length L1 of the coil portion 10. Note that this verification was carried out in an environment where the load on the filament 3 is higher than during actual use of a filament lamp, and in this verification, if the rate of detachment is 10% or less (rating B), it is considered that there is no substantial problem with the product.

[0087] In addition, in the above-mentioned verification 1, d2 was set to 6 mm. Therefore, in the verification 1, it can be said that there was no result in which the filament 3 came off the supporter 5a.

[0088] The filament 3 softens when heated to a high temperature and sags in the direction of gravity due to its own weight. In view of this, it is considered that the length to which the filament 3 extends when heated to a high temperature depends on the length L1 of the coil portion 10. As mentioned above, in a single-end type filament lamp for heating, the length L1 of the coil portion 10 is typically set to 20 mm to 26 mm. In this verification, a filament lamp with L1 of 24 mm was used as an example, but it is presumed that a similar tendency will be obtained within the above range of length L1. Therefore, it can be said that the detachment of the filament 3 from the supporter 5a can be suppressed by setting the length d2 by which the second portion 22 extends in the tube axial direction to ¼ or more of L1.

[0089] Furthermore, by making the length d2 equal to or greater than ¼ of the length L1 of the coil portion 10, as shown in Fig. 6, for example, it is possible to prevent the filament 3 from coming off the supporter 5a even if the second portion 22 is not brought close to the inner wall of the arc tube 2. In other words, by setting the length d2 to the above length, it is possible to easily manufacture a filament lamp in which the filament 3 is prevented from coming off.

[0090] In addition, when the lengths L1 of the multiple coil portions 10 of the filament 3 are different, the length d2 to which the second part 22 of the supporter 5a extends may be determined based on the length L1 of the coil portion 10 connected to the connecting portion 11 that engages with the supporter 5a.

[0091] Furthermore, according to the results of this verification, it is preferable that the length d1 (see FIG. 5) of the first portion 21 in the Z direction is equal to or greater than ¼ of the length L1 of the coil portion 10. Since the first portion 21 is connected to the fixed portion 20 of the supporter 5a, even if the length d1 is shorter than ¼ of L1, the filament 3 is unlikely to come off the supporter 5a. However, from the viewpoint of moving the coil portion 10 away from the tube axis A1 within the range in which the filament 3 extends at high temperatures, as described in FIG. 8A, it is preferable that the length d1 is equal to or greater than ¼ of the length L1 of the coil portion 10.

[0092] [Variations] Below, modified examples of the filament lamp according to the present invention will be explained.

[0093] <1> Figure 11A is a drawing showing yet another example of the configuration of the supporter 5a of the filament lamp 1. In the above, the first portion 21 and the second portion 22 have been described as being linear, but as shown in Figure 11A, the supporter 5a may have the first portion 21 and the second portion 22 that are curved.

[0094] Fig. 11B is an enlarged view of the supporter 5a shown in Fig. 11A. In the example of Fig. 11B, similarly to the above embodiment, the second portion 22 corresponds to the portion of the supporter 5a that extends from the portion located on the -Z side toward the end farthest from the tube axis A1, and the first portion 21 corresponds to the portion between the fixing portion 20 and the second portion 22 that moves away from the tube axis A1 as it moves toward the +Z side. The same is true for the fixing portion 20 and the bent portion 24.

[0095] As shown in Figures 11A and 11B, even when the supporter 5a is curved, the first portion 21 and the second portion 22 have a shape that moves away from the tube axis A1 as they move away from the filament 3, thereby preventing short circuits of the multiple coil portions 10.

[0096] <2> Fig. 12A is a drawing showing another example of the configuration of the supporter 5a of the filament lamp 1, following Fig. 11A. Also, Fig. 12B is a drawing showing an enlarged view of the supporter 5a shown in Fig. 12A. As shown in Fig. 12A, the second portion 22 of the supporter 5a may be disposed closer to the tube axis A1 than the first portion 21.

[0097] 12A and 12B, the fixing part 20 corresponds to a part of the supporter 5a supported by the support member 4a. The first part 21 corresponds to a part that is connected to the fixing part 20 and extends from a part of the supporter 5a located on the -Z side toward the fixing part 20 so as to move away from the tube axis A1 as it moves toward the +Z side. The bent part 24 corresponds to a part that extends from the first part 21 on the opposite side to the fixing part 20, and the second part 22 corresponds to a part that extends from the bent part 24 on the opposite side to the first part 21 so as to move away from the tube axis A1 as it moves toward the +Z side.

[0098] <3> Fig. 13A is a drawing showing yet another example of the configuration of the supporter 5a of the filament lamp 1. Fig. 13B is a drawing showing an enlarged view of the supporter 5a shown in Fig. 13A. As shown in Fig. 13A, the supporter 5a may have a third portion 23 that extends from the end of the second portion 22 opposite the bent portion 24 and contacts the first portion 21.

[0099] As shown in FIG. 13A, by holding the filament 3 within a closed area consisting of the first portion 21, the second portion 22, the third portion 23, and the folded portion 24, the filament 3 is prevented from coming off the supporter 5a, for example, when the filament lamp 1 is subjected to an impact during transportation or when it is attached to a light heating device or the like.

[0100] In addition, when the supporter 5a has the third portion 23, the length d2 of the extension portion of the second portion 22 corresponds to the length from the bent portion 24 in the tube axis direction to the third portion 23 as shown in FIG. 13B. In consideration of the results of the above-mentioned verification 2, if the length d2 is shorter than 1 / 4 of the length L1, the filament 3 will further extend in the tube axis direction after it extends and abuts against the third portion 23. In this case, the filament 3 will have nowhere to go and will bend, increasing the possibility of short-circuiting with other filaments 3. In other words, the length d2 can be said to be a range within which the filament 3 can move when it extends. Therefore, the length d2 is preferably set to 1 / 4 or more of the length L1 of the coil portion 10.

[0101] In FIG. 13A, the supporter 5a has the third portion 23, thereby forming the above-mentioned blocked area. However, the above-mentioned blocked area may be formed by making the first portion 21 and the second portion 22 contact each other, so that 0°<θ2<θ1 holds.

[0102] <4> In the above description, the filament 3 having eight coil portions is disposed within the arc tube 2, but the number of coil portions 10 of the filament 3 is arbitrary.

[0103] For example, a filament 3 having two coil portions 10 and one connecting portion 11 may be disposed within the arc tube 2. In this case, one supporter 5a disposed on the +Z side of the arc tube 2 engages with the connecting portion 11 of the filament 3. In other words, in the above, the supporter 5b disposed on the -Z side of the filament 3 is an optional configuration.

[0104] Even in this case, by configuring the supporter 5a as described in the above embodiment, when the filament 3 becomes hot and expands, the connection portion 11 is prevented from coming off the supporter 5a. Also, the supporter 5a restricts the direction in which the two coil portions 10 move to a direction away from the tube axis A1. This prevents the two coil portions from moving in unexpected directions, which prevents the filament 3 from shorting out, thereby extending the life of the filament lamp.

[0105] <5> In the above, it has been explained that the filament lamp 1 is lit with its tube axis A1 arranged to extend in the vertical direction. However, the tube axis A1 of the filament lamp 1 may also be arranged at an angle to the vertical direction. Even in this case, it is expected that the filament 3 will extend in the tube axis direction due to the vertical component of the filament 3's own weight. However, with the filament lamp 1 configured as described above, even if the filament 3 extends in the tube axis direction, short-circuiting of the filament 3 is suppressed, so that even if the filament lamp 1 is arranged at an angle to the vertical direction, the effect of an excellent lifespan is achieved.

[0106] The configuration of the filament lamp 1 according to the present invention is not limited to the embodiment described above. [Explanation of symbols]

[0107] 1,51 : Filament lamp 2: Arc tube 3: Filament 3a, 3b: Ends of the filament 4a, 4b: Support members 5a,5b,50: Supporter 6: Power supply section 7a,7b: Metal foil 8a,8b: Internal leads 9: Sealing part 10: Coil section 11 : Connection part 12: Support rod 13: Remaining part of exhaust pipe 14: Bass 15: Terminal 20: Fixed part 21: First part 22: Second part 23: Third part 24: Bending section 30,31: End of the arc tube A1: Tube shaft

Claims

1. an arc tube having a pair of power supply parts formed on a first end side; a filament having a plurality of coil portions and at least one connecting portion, the coil portions and the connecting portions being alternately connected between the pair of power supply portions; a support member fixed to a second end side of the arc tube opposite to the first end side; a supporter having a fixed portion supported by the supporting member, a bent portion, a first portion connecting one end of the bent portion and the fixed portion, and a second portion extending from the other end of the bent portion, the bent portion engaging with the connecting portion of the filament when supported by the supporting member, A filament lamp, characterized in that the first portion and the second portion have a shape in which the distance from the tube axis of the light-emitting tube increases as the distance from the filament increases, or a shape in which the distance from the tube axis is constant.

2. 2. A filament lamp as defined in claim 1, wherein said first portion and said second portion are linear.

3. The filament lamp described in claim 2, characterized in that the first portion and the second portion have a shape that moves away from the tube axis of the light-emitting tube as they move away from the filament, and when the angle formed by the first portion and the tube axis is θ1, θ1 satisfies the following formula (1). 0°<θ1≦30° (1)

4. The second portion is disposed at a position farther from the tube axis than the first portion, 3. A filament lamp as described in claim 2, characterized in that when the angle between the first portion and the tube axis is θ1 and the angle between the second portion and the tube axis is θ2, the following formula (2) is satisfied: θ1<θ2 (2)

5. A filament lamp as described in any one of claims 1 to 4, characterized in that the length of the second portion in the tube axial direction of the extension from the bent portion is 1 / 4 or more of the length of the coil portion.

6. 6. A filament lamp according to claim 5, wherein said supporter has a third portion extending from an end of said second portion opposite said bent portion and in contact with said first portion.

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