JP7488960B2 - Light irradiation device - Google Patents

Description

The present invention relates to a light irradiation device comprising an LED unit having a plurality of LED elements and a heat dissipation device that dissipates heat from the LED unit.

Conventionally, ultraviolet-curable inks that are cured by exposure to ultraviolet light have been used as printing inks. Also, ultraviolet-curable resins are used as adhesives around FPDs (Flat Panel Displays), such as liquid crystal panels and organic EL (Electro Luminescence) panels. To cure such ultraviolet-curable inks and ultraviolet-curable resins, an ultraviolet light irradiation device that irradiates ultraviolet light is generally used.

Conventionally, lamp-type irradiation devices that use a high-pressure mercury lamp or a mercury-xenon lamp as a light source have been known as ultraviolet light irradiation devices. However, in recent years, due to demands for reduced power consumption, longer life, and more compact device size, ultraviolet light irradiation devices that use LEDs (Light Emitting Diodes) as a light source instead of conventional discharge lamps have been put into practical use (for example, Patent Document 1).

The light irradiation device described in Patent Document 1 is equipped with an LED unit equipped with many LEDs. When LEDs are used as a light source in this way, most of the input power becomes heat, which causes problems such as reduced light emission efficiency and lifespan due to the heat generated by the LEDs themselves, making heat disposal an issue. Therefore, the light irradiation device described in Patent Document 1 is configured to include a water-cooled cooling device on the back side of the LED unit, which dissipates the heat generated by the LEDs.

Furthermore, because such water-cooled cooling devices require reliability against water leakage, a configuration has been proposed in which a stainless steel pipe that forms the flow path through which the cooling water flows is used as a core, and a heat sink is integrally molded around the pipe by die-casting (for example, Patent Document 2).

Patent No. 5834989 JP 2000-340728 A

When the heat sink of Patent Document 2 is applied to a light irradiation device, the LEDs are efficiently cooled by the cooling water. In addition, because the seamless stainless steel pipe is integrally molded, it is highly reliable against water leakage and has excellent corrosion resistance.

However, because the heat sink in Patent Document 2 is die-cast around a pipe, the aluminum of the heat sink body is interposed between the heat source (e.g., an LED unit) placed on the heat sink and the pipe through which the cooling water flows, which creates thermal resistance and reduces the cooling capacity.

The present invention has been made in consideration of these circumstances, and its object is to provide a light irradiation device that is highly reliable against water leakage, has excellent corrosion resistance, and is equipped with a heat dissipation device with high cooling capacity.

In order to achieve the above object, the light irradiation device of the present invention is a light irradiation device comprising an LED unit having a substrate and an LED element arranged on the substrate, and a heat dissipation device arranged in close contact with the LED unit and dissipating heat from the LED unit, characterized in that the heat dissipation device comprises a metal pipe through which cooling water flows, and a metal support member having a first main surface in close contact with the LED unit and supporting the pipe in the longitudinal direction such that a portion of the outer circumferential surface of the pipe is exposed from the first main surface, the portion of the outer circumferential surface of the pipe having a flat portion located on the same plane as the first main surface, and the flat portion being thermally joined to the LED unit.

With this configuration, the flat surface of the pipe is in direct contact with the LED unit, so the thermal resistance is extremely low and the heat from the LED unit is efficiently dissipated. In addition, because the configuration includes seamless metal pipes, it is highly reliable against water leakage and has excellent corrosion resistance.

It is also desirable that the thickness of the flat portion of the pipe is thinner than the thickness of the portions other than the flat portion.

It is also desirable that the cross section of the pipe be a D-shape formed by cutting off a portion of a circle or ellipse.

It is also desirable that the cross section of the pipe be oval in shape.

It is also desirable for the cross section of the pipe to be angular.

It is also desirable for the support member to have a groove portion into which portions of the pipe other than the flat surface fit.

It is also desirable to have a heat diffusion member between the LED unit and the flat surface of the pipe to diffuse heat from the LED unit. In this case, it is also desirable for the heat diffusion member to be either a vapor chamber, a heat pipe, or a thin heat pipe.

It is also desirable to have thermal grease or a thermal sheet between the LED unit and the first main surface.

In addition, it is desirable for the LED unit to have a base plate on which the substrate is placed, and to have thermal grease or a thermal dissipation sheet between the substrate and the base plate.

It is also desirable that the LED element is positioned opposite the flat portion of the pipe across the substrate.

It is also desirable that the pipe be made of stainless steel, aluminum alloy or copper alloy.

It is also desirable for the LED element to emit ultraviolet light.

As described above, the present invention provides a light irradiation device that is highly reliable against water leakage, has excellent corrosion resistance, and is equipped with a heat dissipation device with high cooling capacity.

FIG. 1 is a diagram illustrating the configuration of a light irradiation device according to a first embodiment of the present invention. FIG. 2 is a perspective view of a heat dissipation device provided in the light irradiation device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view for explaining the configuration of a light irradiation device provided with a conventional heat dissipation device as a comparative example of the present invention. FIG. 4 is a cross-sectional view illustrating the configuration of a light irradiation device according to a second embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating the configuration of a light irradiation device according to a third embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating the configuration of a light irradiation device according to a fourth embodiment of the present invention. 7A to 7C are diagrams illustrating a method for manufacturing a heat dissipation device provided in a light irradiation device according to a fourth embodiment of the present invention. FIG. 8 is a cross-sectional view illustrating the configuration of a light irradiation device according to a fifth embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating the configuration of a light irradiation device according to a sixth embodiment of the present invention.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals and their description will not be repeated.

First Embodiment
FIG. 1 is a diagram for explaining the configuration of a light irradiation device 1 according to a first embodiment of the present invention, in which FIG. 1(a) is a plan view, and FIG. 1(b) is a cross-sectional view taken along line A-A in FIG. 1(a). The light irradiation device 1 of this embodiment is a device for curing ultraviolet-curable ink used as printing ink or ultraviolet-curable resin used as an adhesive in FPD (Flat Panel Display) or the like, and is disposed opposite to an irradiation object, and emits ultraviolet light to a predetermined area of the irradiation object. In this specification, the direction in which the pipes 210 and 220 of the heat dissipation device 200 extend is defined as the X-axis direction, the emission direction of the ultraviolet light emitted from the LED element 103 is defined as the Z-axis direction, and the direction perpendicular to the X-axis and Z-axis is defined as the Y-axis direction.

(Configuration of the Light Irradiation Device 1)
As shown in FIG. 1 , a light irradiation device 1 of this embodiment includes an LED unit 100 and a heat dissipation device 200 .

(Configuration of LED unit 100)
The LED unit 100 includes a substrate 101 in the shape of a rectangular plate defined by an X-axis direction and a Y-axis direction, a plurality of LED elements 103 arranged on the substrate 101 , and a base plate 105 .
The substrate 101 is a rectangular wiring substrate made of a material with high thermal conductivity (e.g., copper, aluminum, aluminum nitride), and 19 (X-axis direction) x 5 (Y-axis direction) LED elements 103 are mounted on the surface of the substrate 101 at predetermined intervals in the X-axis direction and the Y-axis direction. In addition, an anode pattern (not shown) and a cathode pattern (not shown) for supplying power to each LED element 103 are formed on the substrate 101, and each LED element 103 is soldered to the anode pattern and the cathode pattern, respectively, and is electrically connected. The anode pattern and the cathode pattern are electrically connected to an LED drive circuit (not shown), and each LED element 103 is supplied with a drive current from the LED drive circuit via the anode pattern and the cathode pattern.

The LED element 103 is a semiconductor element that includes an LED chip (not shown) with a substantially square light-emitting surface, and receives a drive current from an LED drive circuit to emit ultraviolet light (e.g., wavelengths of 365 nm, 385 nm, 395 nm, and 405 nm). When a drive current is supplied to each LED element 103, each LED element 103 emits ultraviolet light with a quantity of light corresponding to the drive current. In this embodiment, the drive current supplied to each LED element 103 is adjusted so that each LED element 103 emits a substantially uniform quantity of ultraviolet light, and the ultraviolet light emitted from the LED unit 100 has a substantially uniform light quantity distribution in the X-axis direction and the Y-axis direction.

The base plate 105 is a rectangular plate-shaped member made of a metal (e.g., copper, aluminum) with high thermal conductivity. The substrate 101 is placed and fixed on the surface (the surface in the Z-axis direction) of the base plate 105. Note that a thermal grease (not shown) or a thermal sheet (not shown) may be provided between the substrate 101 and the base plate 105 (contact surface) to promote heat transfer between the two.

(Configuration of heat dissipation device 200)
2 is a perspective view illustrating the configuration of the heat dissipation device 200 of this embodiment. The heat dissipation device 200 is disposed so as to be in close contact with the rear surface (the surface opposite to the surface on which the substrate 101 is mounted) of the base plate 105, and is a device that dissipates heat generated by each LED element 103 (FIG. 1(b)).
The heat dissipation device 200 is composed of a pair of pipes 210, 220 and a support member 230. When a drive current flows through each LED element 103 and each LED element 103 emits ultraviolet light, the LED element 103 generates heat, causing a rise in temperature and a significant decrease in light emission efficiency. For this reason, in this embodiment, the heat dissipation device 200 is provided so as to be in close contact with the rear surface of the base plate 105, and the heat generated by the LED element 103 is conducted to the heat dissipation device 200 via the substrate 101 and the base plate 105, forcibly dissipating the heat.

The pair of pipes 210, 220 are seamless straight pipes made of metal (stainless steel, aluminum alloy, copper alloy, etc.) through which cooling water (e.g., water, etc.) passes. The cross section of the pair of pipes 210, 220 is substantially D-shaped with a part of a circle cut off, and flat surfaces 212, 222 (flat surface portions) are formed on parts of the outer circumferential surfaces of the pair of pipes 210, 220, respectively, and cylindrical surfaces 213, 223 continuous with the flat surfaces 212, 222, respectively, are formed on other parts of the outer circumferential surfaces.
The support member 230 is a rectangular plate-shaped metal (e.g., aluminum, copper, stainless steel) member that supports the pipes 210, 220. The surface (surface in the Z-axis direction) of the support member 230 is provided with a contact surface 231 (first main surface) that comes into close contact with the rear surface of the base plate 105, and grooves 235, 236 with a U-shaped cross section (partial circle shape) into which the cylindrical surfaces 213, 223 of the pair of pipes 210, 220 fit.
In this embodiment, the pair of pipes 210, 220 are attached to the grooves 235, 236 of the support member 230 after a thermally conductive adhesive 240 is applied to the cylindrical surfaces 213, 223. When the pair of pipes 210, 220 are attached to the support member 230, the flat surfaces 212, 222 face the Z-axis direction and are mechanically and thermally coupled while being exposed to the abutment surface 231. When the pair of pipes 210, 220 are attached to the support member 230, the abutment surface 231 of the support member 230 and the flat surfaces 212, 222 of the pair of pipes 210, 220 are positioned on approximately the same plane.
In this manner, the pair of pipes 210, 220 of this embodiment are supported (fixed) by the support member 230 so as to extend parallel to the X-axis direction with a predetermined gap therebetween in the Y-axis direction.

The end of the pipe 210 on the negative side in the X-axis direction is a water inlet 211, which is connected to a water supply device (not shown) via a joint (not shown) so that cooling water is supplied to the pipe 210. When cooling water is supplied to the pipe 210, the cooling water flows in the X-axis direction inside the pipe 210. In addition, the end of the pipe 210 on the positive side in the X-axis direction is connected to the end of the pipe 220 on the positive side in the X-axis direction by a U-shaped pipe (not shown), and the cooling water that flows through the pipe 210 flows in the direction opposite to the X-axis direction inside the pipe 220 and is drained from a drain outlet 221 formed at the end of the pipe 210 on the negative side in the X-axis direction. The drain outlet 221 is connected to a water supply device (not shown) via a joint (not shown), and the cooling water drained from the drain outlet 221 is collected in the water supply device, cooled, and then supplied to the pipe 210 again.
In this manner, in this embodiment, the seamless stainless steel pipes 210, 220 are used, which provides high reliability against water leakage and excellent corrosion resistance.
In addition, in Figures 1 and 2, the ends of the pipes 210, 220 protrude from the support member 230 to the + and - sides in the X-axis direction, but the pipes 210, 220 do not necessarily have to protrude from the support member 230 as long as they can cool the entire base plate 105.

As described above, in this embodiment, the heat dissipation device 200 is attached so as to be in close contact with the back surface of the base plate 105. When the heat dissipation device 200 is attached to the base plate 105, the abutment surface 231 of the support member 230 and the flat surfaces 212, 222 of the pair of pipes 210, 220, which are located on approximately the same plane, are in close contact with the back surface of the base plate 105. Therefore, the heat generated by the LED unit 100 is directly conducted to the pair of pipes 210, 220 and dissipated to the cooling water.
Thus, according to the configuration of this embodiment, the flat surfaces 212, 222 of the pair of pipes 210, 220 are in direct contact with the LED unit 100, which is a heat source, so that the thermal resistance between them is extremely low, and the heat of the LED unit 100 is efficiently dissipated. Note that between the abutment surface 231 of the support member 230 (and the flat surfaces 212, 222 of the pair of pipes 210, 220) and the base plate 105 (contact surface), a heat dissipation grease (not shown) or a heat dissipation sheet (not shown) may be provided to promote heat transfer between them.

(Effectiveness verification experiment)
Tables 1 and 2 show the results of an effect confirmation experiment conducted by the present inventor. Table 1 shows the experimental results of the light irradiation device 1 (six devices) of the present embodiment, and Table 2 shows the experimental results of the light irradiation device 1Z (one device) of the comparative example.

In the experiment shown in Table 1, six light irradiation devices 1 of this embodiment were prepared, 19 temperature sensors (CH1 to CH19) were attached at equal intervals along the X-axis direction on the substrate 101 of each light irradiation device 1, all LED elements 103 were turned on at maximum output, and the temperature was measured after 5 minutes. The maximum output of the LED unit 100 used in the experiment was 7600W.
The cooling water had a flow rate of 30 L/min and a water temperature of 25°C.

FIG. 3 is a cross-sectional view showing the configuration of a light irradiation device 1Z as a comparative example of this embodiment.
As shown in Fig. 3, in the experiment of Table 2, a heat dissipation device 200Z consisting of a pair of pipes 210Z and 220Z with circular cross sections and a support member 230Z through which the pipes 210Z and 220Z penetrate was fabricated to imitate the configuration of the heat sink in Patent Document 2, and the heat dissipation device 200Z was attached to the LED unit 100 of the present embodiment to form a light irradiation device 1Z of the comparative example. In other words, the light irradiation device 1Z of the comparative example differs from the light irradiation device 1 of the present embodiment in that the heat dissipation device 200Z has a conventional configuration.
In the experiment of Table 2, similarly to the experiment of Table 1, 19 temperature sensors (CH1 to CH19) were attached at equal intervals along the X-axis direction on the substrate 101 of the light irradiation device 1Z of the comparative example, and all the LED elements 103 were turned on to measure the temperature after 5 minutes. Note that the maximum output of the LED unit 100 used in this experiment was also 7600 W, but since there was a risk that the temperature would exceed 100°C if turned on at the maximum output, the light output was set to 50% of the maximum output (i.e., 3800 W).
The cooling water had a flow rate of 30 L/min and a water temperature of 25°C.

(Discussion of Experimental Results)
As shown in Table 1, it was confirmed that the light irradiation device 1 of this embodiment maintained a temperature of about 60° C. over the entire substrate 101 even in the maximum output state, and operated stably.
On the other hand, in the light irradiation device 1Z of the comparative example, the temperature reached approximately 65° C. over the entire substrate 101, even though the light output was 50%, which exceeded the experimental results in Table 1.
In this manner, the light irradiation device 1 of this embodiment is equipped with a heat dissipation device 200 configured such that the flat surfaces 212, 222 of a pair of pipes 210, 220 are in direct contact with the LED unit 100, which serves as a heat source, and therefore it has been found that the heat from the LED unit 100 is efficiently dissipated.
Moreover, in the heat dissipation device 200 of this embodiment, the cooling water travels back and forth through the pair of pipes 210, 220 while absorbing heat from the LED unit 100, so that it can be seen that the substrate 101 is cooled uniformly over the entire area in the X-axis direction.

Thus, according to the configuration of this embodiment, there is little variation in cooling capacity in the Y-axis direction and the X-axis direction, and the substrate 101 can be cooled uniformly (evenly), and the 200 LED elements 103 arranged on the substrate 101 are also cooled uniformly. Therefore, no temperature difference occurs between the LED elements 103, and no variation in irradiation intensity due to temperature characteristics occurs.

The above is a description of this embodiment, but the present invention is not limited to the above configuration, and various modifications are possible within the scope of the technical concept of the present invention.

For example, in the present embodiment, the flat surfaces 212, 222 of the pair of pipes 210, 220 are described as being in close contact with the back surface of the base plate 105, but this is not necessarily limited to such a configuration, and it is sufficient that a part of the outer circumferential surface of the pair of pipes 210, 220 is in close contact with the back surface of the base plate 105. However, from the viewpoint of thermal resistance, it is preferable that the contact area between the pair of pipes 210, 220 and the base plate 105 is large, and it is preferable that the flat surfaces 212, 222 are provided as in the present embodiment.

In addition, although the heat dissipation device 200 of this embodiment is provided with a pair of pipes 210, 220, it is not necessarily limited to such a configuration, and may be provided with one pipe or three or more pipes depending on the required cooling capacity and the size of the LED unit 100.

In addition, although the LED unit 100 of this embodiment is provided with a base plate 105 on which the substrate 101 is placed, the base plate 105 is not necessarily required, and the heat dissipation device 200 may be arranged so as to be in close contact with the rear surface of the substrate 101.

In addition, although the LED unit 100 of this embodiment is described as having multiple LED elements 103, it is not necessarily limited to such a configuration and may also be configured to have one LED element 103.

In addition, in this embodiment, the end of pipe 210 on the + side in the X-axis direction and the end of pipe 220 on the + side in the X-axis direction are connected by a U-shaped pipe (not shown) outside the support member 230, but this is not necessarily limited to such a configuration, and it is also possible to place the U-shaped pipe on the support member 230 in a state where it is attached to the pair of pipes 210, 220 (i.e., the U-shaped pipe and the pair of pipes 210, 220 are integrally constructed).

Second Embodiment
Fig. 4 is a cross-sectional view of a light irradiation device 1A according to a second embodiment of the present invention. As shown in Fig. 4, the light irradiation device 1A of this embodiment is different from the light irradiation device 1 of the first embodiment in that it includes a vapor chamber 300 (thermal diffusion member) sandwiched between the flat surfaces 212, 222 of the pair of pipes 210, 220 and the base plate 105A. Note that the base plate 105A of this embodiment has an accommodation groove 105Aa formed therein in which the vapor chamber 300 is accommodated.

The vapor chamber 300 is a plate-shaped member made of metal (e.g., metals such as copper, aluminum, iron, magnesium, etc., or alloys containing these metals) having a hollow portion P in which a working fluid (e.g., water, alcohol, ammonia, etc.) is sealed under reduced pressure. The vapor chamber 300 is attached so that the front surface (the surface on the base plate 105A side) is in close contact with the accommodation groove 105Aa via a heat conductive material such as grease, and receives heat from the LED unit 100, which is a heat source. The back surface (the surface on the heat dissipation device 200 side) of the vapor chamber 300 of this embodiment is attached so as to be in close contact with the flat surfaces 212, 222 of the pair of pipes 210, 220 and the abutment surface 231 of the support member 230.
The vapor chamber 300 of this embodiment has a function of receiving heat from the LED unit 100 and transmitting the heat while diffusing it in the XY plane. When the vapor chamber 300 receives heat from the LED unit 100, the working liquid in the vapor chamber 300 vaporizes, and the vapor moves in the hollow portion P. The heat transmitted to the vapor chamber 300 spreads in the XY plane and is transmitted from the back surface (the surface on the heat dissipation device 200 side) to the pair of pipes 210, 220. Then, when the heat transmitted to the vapor chamber 300 is transmitted to the pair of pipes 210, 220, the vapor of the working liquid releases heat and returns to liquid. By repeating this process, the heat from the LED unit 100 is efficiently transmitted to the pair of pipes 210, 220. Therefore, the heat of the LED unit 100 is more efficiently dissipated.

Although the light irradiation device 1A of this embodiment is provided with a vapor chamber 300, it is sufficient to provide a heat diffusion member that diffuses heat from the LED unit 100, and examples of the heat diffusion member that can be used include a vapor chamber, a heat pipe, a heat dissipation sheet (graphite sheet), heat dissipation grease, heat dissipation gel, etc.

Third Embodiment
5 is a cross-sectional view of a light irradiation device 1B according to a third embodiment of the present invention. As shown in Fig. 5, the light irradiation device 1B of this embodiment differs from the light irradiation device 1 of the first embodiment in that a plurality of LED elements 103 are arranged at positions facing flat surfaces 212, 222 of pipes 210, 220 with a substrate 101 therebetween.

According to the configuration of this embodiment, the distance between each LED element 103, which is a heat source, and the flat surfaces 212, 222 of the pipes 210, 220 is constant, so it is possible to cool each LED element 103 more uniformly. Therefore, there is no temperature difference between each LED element 103, and there is no variation in irradiation intensity due to temperature characteristics.

Fourth Embodiment
Fig. 6 is a cross-sectional view of a light irradiation device 1C according to a fourth embodiment of the present invention. As shown in Fig. 6, the light irradiation device 1C of this embodiment is different from the light irradiation device 1 of the first embodiment in that the wall thickness T1 of the pipes 210C, 220C at the portions where the flat surfaces 212C, 222C (flat surface portions) are formed is thinner than the wall thickness T2 of the other portions (portions where the cylindrical surfaces 213C, 223C are formed).

7A to 7C are diagrams illustrating a manufacturing method of the heat dissipation device 200C of this embodiment.
In manufacturing the heat dissipation device 200C of this embodiment, first, adhesive 240C is applied to the groove portions 235C, 236C of the support member 230C, and two stainless steel straight tube members PM (pipes 210C, 220C) with circular cross sections are inserted into the groove portions 235C, 236C with U-shaped (partially circular) cross sections formed in the support member 230C ( FIG. 7( a) ).
Next, the straight pipe member PM (pipes 210C, 220C) is pressed (pressed) from the + side to the - side in the Z axis direction by a pressing machine so that the portion of the straight pipe member PM (pipes 210C, 220C) protruding from the surface of the support member 230C (the surface on which the abutment surface 231C is formed) becomes approximately flat (FIG. 7B). Through this process, the straight pipe member PM (pipes 210C, 220C) is fixed (pressed) to the support member 230C.
Next, the front surface of the support member 230C is milled (cut) to form the contact surface 231C and the flat surfaces 212C, 222C of the pipes 210C, 220C (FIG. 7C).
Through the above steps, the heat dissipation device 200C is completed.

In other words, in this embodiment as well, as in the first embodiment, the cross section of the pipes 210C, 220C is approximately D-shaped with a portion of a circle cut out, but the abutment surface 231C and the flat surfaces 212C, 222C of the pipes 210C, 220C are milled (cut) so as to be positioned on approximately the same plane, and therefore the thickness T1 of the pipes 210C, 220C at the portions where the flat surfaces 212C, 222C are formed is thinner than the thickness T2 of the other portions (the portions in contact with the groove portions 235C, 236C (i.e., the portions where the cylindrical surfaces 213C, 223C are formed)).
In addition, by milling (cutting), the bent portions BP (portions connecting the planes 212C, 222C and the cylindrical surfaces 213C, 223C) (Figure 7 (b)) of the pipes 210C, 220C are machined into planes, thereby increasing the width of the planes 212C, 222C in the Y-axis direction.
In addition, since the abutment surface 231C and the flat surfaces 212C, 222C of the pipes 210C, 220C are formed by milling (cutting), the surface roughness of the contact surfaces with the LED unit 100 (i.e., the abutment surface 231C, the flat surfaces 212C, 222C) can be reduced and the flatness can be further improved.

Therefore, according to the configuration of this embodiment, compared to the first embodiment, the thickness T1 of the pipes 210C, 220C at the portions where the flat surfaces 212C, 222C are formed is thinner than the thickness T2 at other portions (portions where the cylindrical surfaces 213C, 223C are formed), so the thermal resistance of the pipes 210C, 220C is smaller, and the width of the flat surfaces 212C, 222C in the Y-axis direction is increased (i.e., the contact area with the LED unit 100 is increased), so the thermal resistance of the pipes 210C, 220C is smaller.
Furthermore, the surface roughness of the contact surfaces with the LED unit 100 (that is, the abutment surface 231C, the flat surfaces 212C, 222C) is reduced, and the flatness is increased, so that the thermal resistance between the heat dissipation device 200C and the LED unit 100 is reduced.
Therefore, the heat of the LED unit 100 can be dissipated more efficiently, and the temperature of the LED unit 100 can be further reduced compared to the first embodiment.

Fifth Embodiment
Fig. 8 is a cross-sectional view of a light irradiation device 1D according to a fifth embodiment of the present invention. As shown in Fig. 8, the light irradiation device 1D of this embodiment is different from the light irradiation device 1C of the fourth embodiment in that the cross-sectional shape of grooves 235D and 236D formed in a support member 230D is a partially elliptical shape with the major axis parallel to the Y-axis direction.

Like the heat dissipation device 200C of the fourth embodiment, the heat dissipation device 200D of this embodiment is manufactured by inserting two stainless steel straight tube members PM (pipes 210D, 220D) with circular cross sections into grooves 235D, 236D formed in the support member 230D, pressing (pushing) them from the + side to the - side in the Z-axis direction with a press, and milling (cutting) the surface side of the support member 230D.

In other words, in this embodiment, the cross section of the pipes 210D, 220D is approximately D-shaped with a portion of an ellipse cut out, but as in the fourth embodiment, the abutment surface 231D and the flat surfaces 212D, 222D of the pipes 210D, 220D are milled (cut) so as to be positioned on approximately the same plane, so that the thickness T1 of the pipes 210D, 220D at the portions where the flat surfaces 212D, 222D are formed is thinner than the thickness T2 of the other portions (the portions in contact with the groove portions 235D, 236D (i.e., the portions where the elliptical cylindrical surfaces 213D, 223D are formed)).
Furthermore, since the cross section of the pipes 210D, 220D is substantially D-shaped with a part of an ellipse cut off, the width of the planes 212D, 222D in the Y-axis direction is wider than that of the planes 212C, 222C of the fourth embodiment.

Therefore, according to the configuration of this embodiment, the width of the planes 212D and 222D in the Y-axis direction is wider (i.e., the contact area with the LED unit 100 is increased) compared to the fourth embodiment, and the thermal resistance of the pipes 210D and 220D is reduced accordingly. This allows the heat of the LED unit 100 to be dissipated more efficiently.

Sixth Embodiment
Fig. 9 is a cross-sectional view of a light irradiation device 1E according to a sixth embodiment of the present invention. As shown in Fig. 9, the light irradiation device 1E of this embodiment is different from the light irradiation device 1C of the fourth embodiment in that the cross-sectional shapes of the grooves 235E and 236E formed in the support member 230E are elliptical (a shape obtained by connecting two circles with the same radius by a common circumscribing line).

Like the heat dissipation device 200C of the fourth embodiment, the heat dissipation device 200E of this embodiment is manufactured by inserting two stainless steel straight tube members PM (pipes 210E, 220E) with circular cross sections into grooves 235E, 236E formed in the support member 230E, pressing (pushing) them from the + side to the - side in the Z-axis direction with a press, and milling (cutting) the surface side of the support member 230E.

In other words, in this embodiment, the cross sections of the pipes 210E, 220E are elliptical in shape, but as in the fourth embodiment, the abutment surface 231E and the flat surfaces 212E, 222E of the pipes 210E, 220E are milled (cut) so as to be positioned on approximately the same plane, so that the thickness T1 of the pipes 210E, 220E at the portions where the flat surfaces 212E, 222E are formed is thinner than the thickness T2 of the other portions (the portions in contact with the groove portions 235E, 236E (i.e., the portions where the elliptical cylindrical surfaces 213E, 223E are formed)).
Furthermore, since the cross sections of the pipes 210E, 220E are elliptical, the widths of the planes 212E, 222E in the Y-axis direction are wider than the planes 212C, 222C of the fourth embodiment.

Therefore, according to the configuration of this embodiment, the width of the planes 212E and 222E in the Y-axis direction is wider than in the fourth embodiment (i.e., the contact area with the LED unit 100 is increased), and the thermal resistance of the pipes 210E and 220E is reduced accordingly. This allows the heat of the LED unit 100 to be dissipated more efficiently.

As described above, the cross section of the pipes 210, 220 in the first to fourth embodiments is approximately D-shaped with part of a circle cut off, the cross section of the pipes 210D, 220D in the fifth embodiment is approximately D-shaped with part of an ellipse cut off, and the cross section of the pipes 210E, 220E in the sixth embodiment is oval-shaped; however, as long as the base plate 105 (105A) can be cooled, for example, a pipe having a rectangular (rectangular, square) or polygonal cross section can also be used.

It should be noted that the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

1: Light irradiation device 1A: Light irradiation device 1B: Light irradiation device 1C: Light irradiation device 1D: Light irradiation device 1E: Light irradiation device 1Z: Light irradiation device 100: LED unit 101: Substrate 103: LED element 105: Base plate 105A: Base plate 105Aa: Housing groove 200: Heat dissipation device 200C: Heat dissipation device 200D: Heat dissipation device 200E: Heat dissipation device 200Z: Heat dissipation device 210: Pipe 210C: Pipe 210D: Pipe 210E: Pipe 210Z: Pipe 211: Water intake port 212: Plane 212C: Plane 212D: Plane 212E: Plane 213: Cylindrical surface 213C: Cylindrical surface 213D: Elliptical cylindrical surface 213E: Long cylindrical surface 220: Pipe 220C : Pipe 220D : Pipe 220E : Pipe 220Z : Pipe 221 : Drain port 222 : Plane 222C : Plane 222D : Plane 222E : Plane 223 : Cylindrical surface 223C : Cylindrical surface 223D : Elliptical cylindrical surface 223E : Long cylindrical surface 230 : Support member 230C : Support member 230D : Support member 230E : Support member 230Z : Support member 231 : Contact surface 231C : Contact surface 231D : Contact surface 231E : Contact surface 235 : Groove 235C : Groove 235D : Groove 235E : Groove 236 : Groove 236C : Groove 236D : Groove 236E : Groove 240 : Adhesive 240C : Adhesive 240D : Adhesive 240E : Adhesive 300 : Vapor chamber

Claims (13)

An LED unit having a substrate and an LED element disposed on the substrate;
a heat dissipation device disposed in close contact with the LED unit and dissipating heat from the LED unit;
A light irradiation device comprising:
The heat dissipation device includes:
Metal pipes through which cooling water flows,
a metal support member having a first main surface that is in close contact with the LED unit and that supports the pipe in a longitudinal direction such that a portion of an outer circumferential surface of the pipe is exposed from the first main surface;
having
A part of the outer circumferential surface of the pipe has a flat portion located on the same plane as the first main surface,
A light irradiation device, characterized in that the planar portion is thermally joined to the LED unit. The light irradiation device according to claim 1, characterized in that the thickness of the flat portion of the pipe is thinner than the thickness of the portion other than the flat portion. The light irradiation device according to claim 1 or 2, characterized in that the cross section of the pipe is a D-shape obtained by cutting a part of a circle or an ellipse. The light irradiation device according to claim 1 or 2, characterized in that the cross section of the pipe is oval in shape. The light irradiation device according to claim 1 or 2, characterized in that the cross section of the pipe is angular. A light irradiation device as described in any one of claims 1 to 5, characterized in that the support member has a groove portion into which the portion of the pipe other than the flat portion fits. A light irradiation device as described in any one of claims 1 to 6, characterized in that a heat diffusion member that diffuses heat from the LED unit is provided between the LED unit and the flat portion of the pipe. The light irradiation device described in claim 7, characterized in that the heat diffusion member is either a vapor chamber, a heat pipe or a thin heat pipe. A light irradiation device as described in any one of claims 1 to 8, characterized in that a thermal dissipation grease or a thermal dissipation sheet is provided between the LED unit and the first main surface. The LED unit has a base plate on which the substrate is placed,
10. The light irradiation device according to claim 1, further comprising a heat dissipation grease or a heat dissipation sheet between the substrate and the base plate. A light irradiation device as described in any one of claims 1 to 10, characterized in that the LED element is arranged in a position facing the flat portion of the pipe across the substrate. The light irradiation device according to any one of claims 1 to 11, characterized in that the pipe is made of stainless steel, an aluminum alloy or a copper alloy. A light irradiation device as described in any one of claims 1 to 12, characterized in that the LED element emits ultraviolet light.

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