JP7521755B2 - Radiation-resistant straight tube LED lamp and lighting device - Google Patents

Description

The present invention relates to radiation-resistant straight-tube LED lamps and lighting devices for use in nuclear facilities and other facilities.

Traditionally, straight-tube mercury lamps have been used in nuclear facilities as lighting that can be used in high-radiation environments and nitric acid atmospheres. However, a treaty on mercury has banned their manufacture, making it difficult to obtain new mercury lamps. For this reason, efforts are underway to develop lamps that can replace mercury lamps (see, for example, Patent Document 1).

JP 2019-87334 A

Lamps for use in nuclear facilities must be radiation-resistant, resistant to nitric acid atmospheres, and have a high light output. In addition, because replacing lamps in nuclear facilities requires a lot of effort, lamps with a long lifespan are preferred.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a lamp suitable for use in nuclear facilities.

The radiation-resistant straight tube LED lamp according to one embodiment of the present invention includes a light source unit having a light source substrate with an inorganic insulating reflective film formed on its surface and an LED element mounted on the inorganic insulating reflective film of the light source substrate, a heat sink supporting the light source unit on its front surface and having a number of fins standing on its rear surface, a base attached to each of both longitudinal end surfaces of the heat sink and detachable from a socket to which power is supplied, a ring packing disposed between the end surface of the heat sink and the base, and a conductive wire electrically connecting the base and the LED element, the heat sink having an internal passage opening to the end surface and the front surface, and the conductive wire electrically connecting the base and the LED element through the inside of the ring packing and the internal passage.

The present invention makes it possible to obtain a radiation-resistant straight-tube LED lamp suitable for use in nuclear facilities.

FIG. 2 is a schematic diagram illustrating the configuration of a lighting device. FIG. FIG. FIG. 2 is an exploded perspective view of a radiation-resistant straight tube LED lamp. FIG. FIG. 2 is an external perspective view of a radiation-resistant straight-tube LED lamp. 7 is a cross-sectional view taken along line VII-VII in FIG. 6.

The lighting device 1 according to the embodiment will be described below with reference to the drawings. Note that the embodiment of the present invention described below is an example of how the present invention can be realized, and the scope of the present invention is not limited to the scope of the embodiment. Therefore, the present invention can be implemented by making various modifications to the embodiment.

Figure 1 is a schematic diagram of the lighting device 1. Figure 2 is a perspective view of the casing 2. Figure 3 is a front view of the casing 2. As shown in Figures 1 to 3, the lighting device 1 mainly comprises the casing 2, sockets 3a and 3b, an AC/DC converter 4, a power cable 5, and a radiation-resistant straight-tube LED lamp 10.

The lighting device 1 is suitable for use in high radiation environments (e.g., cumulative radiation dose of 100 kGy) such as nuclear facilities. The high radiation environment is surrounded by a thick radiation protection wall. In other words, almost no radiation leaks outside the radiation protection wall. In addition, the inside of the radiation protection wall may be a nitric acid atmosphere.

As shown in FIG. 1, among the components of the lighting device 1, the casing 2, sockets 3a and 3b, and radiation-resistant straight-tube LED lamp 10 are placed inside the radiation protection wall, while the facility power source (external power source) and AC/DC converter 4 are placed outside the radiation protection wall, and the AC/DC converter 4 and the sockets 3a and 3b are connected by a power cable 5.

The casing 2 is attached, for example, to the inside of a radiation protection wall. The casing 2 also supports the sockets 3a and 3b. The casing 2 according to this embodiment supports two sets of sockets 3a and 3b, but the number of sets of sockets 3a and 3b is not limited to this.

The sockets 3a and 3b are arranged opposite each other with a distance equal to the length of the radiation-resistant straight-tube LED lamp 10. The sockets 3a and 3b are configured to allow the bases 13a and 13b of the radiation-resistant straight-tube LED lamp 10 to be detachably attached. The sockets 3a and 3b supply DC power supplied through the power cable 5 to the bases 13a and 13b.

The AC/DC converter 4 converts AC power supplied from the facility power source into DC power and supplies the DC power to the sockets 3a and 3b via the power cable 5. The AC/DC converter 4 is composed of, for example, a diode bridge.

The casing 2, sockets 3a, 3b, and power cable 5 are the same as those in conventional lighting devices that use mercury lamps. In other words, these can be used with existing equipment. On the other hand, the AC/DC converter 4 is installed in place of the ballast in a lighting device that uses a mercury lamp.

Figure 4 is an exploded perspective view of the radiation-resistant straight-tube LED lamp 10. Figure 5 is a perspective view of the light source unit 12. Figure 6 is an external perspective view of the radiation-resistant straight-tube LED lamp 10. Figure 7 is a cross-sectional view taken along line VII-VII in Figure 6. As shown in Figures 4 to 7, the radiation-resistant straight-tube LED lamp 10 mainly includes a heat sink 11, a light source unit 12, bases 13a and 13b, ring packings 14a, 14b, 15a, and 15b, insulators 16a and 16b, a front cover 19, and conductive wires 28a and 28b.

The heat sink 11 has a generally rectangular parallelepiped outer shape. The heat sink 11 is formed as a single unit from, for example, an aluminum alloy. The heat sink 11 supports the light source unit 12 on the front surface 11a, and has multiple fins 11c standing on the back surface 11b opposite the front surface 11a. The multiple fins 11c are arranged at predetermined intervals in the longitudinal direction of the heat sink 11. The heat sink 11 is also an elongated member that is long in the direction of the opposing end surfaces 11d, 11e.

Furthermore, as shown in FIG. 4, the heat sink 11 has internal passages 11f and 11g formed therein. The internal passage 11f passes through the inside of the heat sink 11 and opens to the front surface 11a and end surface 11d. The internal passage 11g passes through the inside of the heat sink 11 and opens to the front surface 11a and end surface 11e. The internal passages 11f and 11g are spaces through which the conductive wires 28a and 28b pass.

The light source unit 12 is a member that emits light when DC power is supplied through the bases 13a and 13b and the conductive wires 28a and 28b. The light source unit 12 is supported on the front surface of the heat sink 11. As shown in FIG. 5, the light source unit 12 mainly includes a light source substrate 12a, a frame 12b, an LED element 12c, and electrodes 12d and 12e.

As shown in FIG. 5, the light source substrate 12a is a plate-shaped member. An inorganic insulating reflective film 12f is formed on the surface of the light source substrate 12a (the surface opposite the heat sink 11). The light source substrate 12a supports the frame 12b, the LED element 12c, and the electrodes 12d and 12e on the inorganic insulating reflective film 12f.

The inorganic insulating reflective film 12f is mainly composed of, for example, white inorganic powder (white inorganic pigment) and silicon dioxide (SiO ₂ ). The inorganic insulating reflective film 12f is formed on the light source substrate 12a by applying and baking an ink in which the white inorganic powder and silicon dioxide are mixed in a diethylene glycol monobutyl ether solvent containing organic phosphoric acid.

Examples of the white inorganic powder include titanium oxide, zinc oxide, alumina, or a combination of these. The content of the white inorganic powder in the inorganic insulating reflective film 12f is adjusted appropriately depending on the required reflectance, etc., but is preferably 40 to 70% by weight, and more preferably 50 to 65% by weight. A content of 40% by weight or more provides a sufficient reflective effect, while a content of 70% by weight or less ensures the ink fluidity required to form a uniform film.

The frame 12b is attached to the surface of the light source substrate 12a. The LED elements 12c are housed inside the frame 12b. In FIG. 5, two frames 12b are attached to one light source substrate 12a, and one frame 12b houses two LED elements 12c, but the number of frames 12b and LED elements 12c is not limited to this.

The inside of the frame 12b is filled with transparent resin 12g. In other words, the LED element 12c inside the frame 12b is molded with the transparent resin 12g. The transparent resin 12g is, for example, an epoxy-based or silicone-based resin. In addition, by mixing a phosphor of any color (for example, yellow, red, or green) into the transparent resin 12g, the light output from the LED element 12c can be converted to a desired color.

The electrodes 12d and 12e are attached to both longitudinal ends of the light source substrate 12a. One end of the conductive wires 28a and 28b passing through the internal passages 11f and 11g is electrically connected to the electrodes 12d and 12e. The electrode 12d, the multiple LED elements 12c, and the electrode 12e are connected in series.

As shown in FIG. 4, the bases 13a and 13b are attached to the end faces 11d and 11e on both sides of the heat sink 11 in the longitudinal direction. The distance between the tips of the bases 13a and 13b corresponds to the distance between the sockets 3a and 3b. As shown in FIG. 7, electrodes 27a and 27b are provided inside the bases 13a and 13b. The bases 13a and 13b are connected to the sockets 3a and 3b, so that the electrodes 27a and 27b are electrically connected to the power cable 5. Furthermore, the other ends of the conductive wires 28a and 28b that pass through the internal passages 11f and 11g are electrically connected to the electrodes 27a and 27b.

As shown in FIG. 4, the ring packings 14a, 15a and the insulator 16a have a ring-shaped outer shape with a through hole formed in the center. The ring packings 14a, 15a and the insulator 16a are arranged between one end face 11d of the heat sink 11 and the base 13a. More specifically, the ring packing 14a (first ring packing) abuts against the end face 11d so as to surround the opening on the end face 11d side of the internal passage 11f. The ring packing 15a (second ring packing) abuts against the base 13a. The insulator 16a is sandwiched between the ring packings 14a, 15a. This makes the space from the base 13a through the inside of the ring packings 14a, 15a and the insulator 16a to the internal passage 11f airtight.

The ring packing 14a and the insulator 16a are then fastened to the heat sink 11 by bolts 17a. The base 13a and the ring packing 15a are then fastened to the heat sink 11 by bolts 18a. However, the method of fastening the base 13a, the ring packings 14a and 15a, and the insulator 16a to the heat sink 11 is not limited to the above-mentioned example.

The ring packings 14a and 15a are formed, for example, from EPDM (ethylene propylene rubber), which has high radiation resistance. The insulator 16a is formed, for example, by cutting a PEEK (polyether ether ketone) material, which has high mechanical strength and radiation resistance. However, the materials of the ring packings 14a and 15a and the insulator 16a are not limited to the above examples.

The ring packings 14b, 15b and the insulator 16b are disposed between the other end face 11e of the heat sink 11 and the base 13b. The configuration, positional relationship, material, and fixing method of the ring packings 14b, 15b and the insulator 16b are the same as those of the ring packings 14a, 15a and the insulator 16a, so a repeated explanation will be omitted.

The front cover 19 is attached to the front surface 11a of the heat sink 11 as shown in FIG. 4. The front cover 19 transmits the light output from the LED elements 12c and airtightly seals the space in which the light source unit 12 and the openings on the front surface 11a side of the internal passages 11f and 11g are located. As shown in FIG. 4, the front cover 19 mainly comprises a body 20, a glass sheet 21, a pressing plate 22, and a number of frame-type gaskets 23, 24, and 25.

The body 20, the pressing plate 22, and the frame-type packings 23 to 25 are all frame-type that fit the outer edge of the front surface 11a of the heat sink 11. On the other hand, the glass sheet 21 is plate-shaped to match the shape of the front surface 11a of the heat sink 11.

The body 20 is integrally formed from an aluminum alloy or stainless steel. The body 20 is disposed so as to surround the light source unit 12 and the openings on the front surface 11a side of the internal passages 11f and 11g. The inner surface of the body 20 may be mirror-finished so as to reflect the light output from the LED element 12c.

The glass plate 21 is disposed outside the body 20 in a position facing the light source unit 12. The pressing plate 22 is disposed further outside than the glass plate 21. The pressing plate 22 is fastened to the heat sink 11 by bolts 26, thereby pressing the glass plate 21 and the body 20 against the front surface 11a of the heat sink 11.

The frame-type packings 23 to 25 are disposed between the front surface 11a of the heat sink 11, the body 20, the glass sheet 21, and the pressing plate 22. More specifically, the frame-type packing 23 is located between the front surface 11a of the heat sink 11 and the body 20, the frame-type packing 24 is located between the body 20 and the glass sheet 21, and the frame-type packing 25 is located between the glass sheet 21 and the pressing plate 22.

The conductive wires 28a and 28b are, for example, twisted pairs covered with an insulating coating. Typically, the conductive wires 28a and 28b are Kapton (registered trademark) wires. The conductive wire 28a passes through the through holes (inside) of the ring packings 14a and 15a and the insulator 16a and the internal passage 11f, and is connected to the electrodes 12d and 27a.

More specifically, as shown in FIG. 7, the conductive wire 28a extending from the electrode 27a enters the internal passage 11f through the airtight space inside the ring packings 14a, 15a and the insulator 16a. After passing through the internal passage 11f, the conductive wire 28a is connected to the electrode 12d in the airtight space formed between the front surface 11a of the heat sink 11 and the front cover 19. The same applies to the conductive wire 28b.

The above embodiment provides the following advantages:

According to the above embodiment, the space through which the conductive wire 28a connecting the electrodes 12d and 27a passes is made airtight, thereby suppressing performance degradation due to the nitric acid atmosphere. In addition, by using a twisted pair wire covered with an insulating coating as the conductive wire 28a, performance degradation due to the nitric acid atmosphere is further suppressed. Furthermore, by passing the conductive wire 28a through the ring packings 14a and 15a, the insulator 16a, and the internal passage 11f, the Kapton wire, which has low flexibility, can be appropriately arranged. The same applies to the conductive wire 28b.

In addition, according to the above embodiment, by using the inorganic insulating reflective film 12f, deterioration in a high radiation environment can be suppressed. As a result, a decrease in the illuminance of the radiation-resistant straight tube type LED lamp 10 can be suppressed. Furthermore, when the radiation-resistant straight tube type LED lamp 10 is used in an even higher radiation environment (e.g., an accumulated radiation dose of 100 kGy or more), the plate glass 21 can be made of synthetic quartz.

In addition, according to the above embodiment, by arranging the AC/DC converter 4 outside the radiation protection wall, it is possible to prevent performance degradation of the AC/DC converter 4 due to radiation. Furthermore, according to the above embodiment, by making maximum use of existing equipment, it is possible to introduce a radiation-resistant straight tube LED lamp 10 suitable for high radiation environments at low cost.

The above describes the embodiments of the present invention, but the conditions in the examples are merely an example of conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to this example of conditions. The present invention can adopt various conditions as long as they do not deviate from the gist of the present invention and achieve the object of the present invention.

1...Lighting device, 2...Casing, 3a, 3b...Socket, 4...AC/DC converter, 5...Power cable, 10...Radiation-resistant straight tube LED lamp, 11...Heat sink, 11a...Front, 11b...Rear, 11c...Fin, 11d, 11e...End surface, 11f, 11g...Internal passage, 12...Light source section, 12a...Light source board, 12b...Frame, 12c...LED element, 12d, 12e, 27a, 27b...electrodes, 12f...inorganic insulating reflective film, 12g...transparent resin, 13a, 13b...base, 14a, 14b, 15a, 15b...ring packing, 16a, 16b...insulator, 17a, 18a, 17b, 18b, 26...bolt, 19...front cover, 20...body, 21...plate glass, 22...pressing plate, 23, 24, 25...frame-type packing, 28a, 28b...conductive wire

Claims (6)

a light source unit including a light source substrate having an inorganic insulating reflective film formed on a surface thereof and an LED element mounted on the inorganic insulating reflective film of the light source substrate;
a heat sink supporting the light source unit at a front surface and having a plurality of fins standing on a rear surface;
a base attached to each of both end faces in the longitudinal direction of the heat sink and adapted to be detachably attached to a socket to which power is supplied;
a ring packing disposed between the end surface of the heat sink and the base;
A radiation-resistant straight tube LED lamp comprising the base and a conductive wire electrically connecting the LED element,
the heat sink has an internal passageway opening to an end face and a front face;
The radiation-resistant straight tube LED lamp is characterized in that the conductive wire passes through the inside of the ring packing and the internal passage to electrically connect the base and the LED element. The radiation-resistant straight tube LED lamp according to claim 1, characterized in that the conductive wire is a twisted pair wire covered with an insulating coating. The ring packing is
a first ring packing in contact with an end surface of the heat sink;
a second ring packing in contact with the base,
3. The radiation-resistant straight tube LED lamp according to claim 1, further comprising a ring-shaped insulator sandwiched between the first ring packing and the second ring packing. The radiation-resistant straight tube LED lamp according to any one of claims 1 to 3, characterized in that it is provided with a front cover that is disposed on the front surface of the heat sink so as to surround the light source unit, allows the light output from the LED element to pass through, and airtightly seals the space in which the light source unit and the front opening of the internal passage are disposed. The front cover is
A framed body and
a plate glass facing the light source unit on the outer side of the body;
a frame-shaped pressing plate that presses the glass plate and the body toward a front surface of the heat sink on the outer side of the glass plate;
5. The radiation-resistant straight tube LED lamp according to claim 4, further comprising a plurality of frame-type gaskets disposed between the front surface of the heat sink, the body, the glass plate, and the pressing plate. The radiation-resistant straight tube LED lamp according to any one of claims 1 to 4, which is installed in a radiation environment surrounded by a radiation protection wall;
and an AC/DC converter that is installed outside the radiation protection wall and converts AC power output from an external power source into DC power and supplies the DC power to the base of the radiation-resistant straight tube LED lamp.

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