Light irradiation apparatus

Abstract

To provide a light irradiation apparatus capable of suppressing increase in temperature of an enclosure by effectively cooling light emitting elements and a drive substrate while having a configuration in which an enclosure covers the entire light irradiation apparatus.SOLUTION: A light irradiation apparatus includes: a light source module including a substrate and light-emitting devices mounted on a first face of the substrate; a heat sink provided to come into contact with a second face of the substrate; a circuit substrate or circuit wiring electrically connected to the light source module; and an enclosure having a first space storing the heat sink and a second space storing the circuit substrate or circuit wiring. The enclosure is provided with: a first opening connecting the first space to the outside of the enclosure; a second opening connecting the second space to the outside of the enclosure; and a third opening connecting the first space to the second space.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light irradiation device that irradiates an object with light, and more particularly to a light irradiation device that includes a light source module and a heat sink that cools the light source module within a housing. [Background technology]

[0002] Conventionally, ultraviolet-curable inks that are cured by irradiation with ultraviolet light have been used as printing inks. In addition, ultraviolet-curable resins are used as sealants for 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. However, particularly in printing and FPD applications, it is necessary to irradiate a wide rectangular irradiation area with ultraviolet light of high irradiation intensity, so a light irradiation device in which a large number of light-emitting elements are arranged on a substrate and opposed to the irradiation area is used.

[0003] In such a light irradiation device using a large number of light-emitting elements, the temperature rises due to heat generated by the light-emitting elements, and the light-emitting efficiency of the light-emitting elements drops significantly. For this reason, a heat dissipation member such as a heat sink is provided in close contact with the substrate, and a coolant such as cooling water is passed through a flow path formed inside the heat dissipation member, forcibly dissipating the heat generated by the light-emitting elements (for example, Patent Document 1).

[0004] The light irradiation device of Patent Document 1 includes a light irradiation device in which a plurality of light emitting elements are arranged, a drive board for driving the plurality of light emitting elements, a heat dissipation member, and a housing that accommodates a cooling pipe for flowing a coolant through the heat dissipation member. The light irradiation device includes a base body having internal electrical wiring and a plurality of light emitting elements arranged on the base body, and functions as an ultraviolet irradiation light source. In addition, the base body of the light irradiation device is bonded to one main surface of the heat dissipation member, and the drive board is bonded to the other main surface of the heat dissipation member, and the heat of the light emitting elements stored in the base body of the light irradiation device and the heat of the electronic circuit stored in the drive board are absorbed by the heat dissipation member and released to the outside. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 034778 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the light irradiation device of Patent Document 1, the heat dissipation member absorbs and dissipates heat from the light emitting element and the driving board, so that it is possible to efficiently cool the light emitting element while suppressing the rise in temperature of the driving board. However, when the entire light irradiation device is housed in one housing as in the configuration of Patent Document 1, there is a problem that part of the ultraviolet light from the light emitting element hits the inner surface of the housing and is repeatedly reflected within the housing, causing the temperature of the housing itself to rise. Similarly, part of the ultraviolet light reflected from the outside of the light irradiation device (the irradiation target member such as paper) may hit the inner surface of the housing, causing a rise in temperature. If the temperature of the housing becomes high in this way, it becomes difficult to perform maintenance work on the light irradiation device, and it becomes difficult to arrange other devices or parts in the vicinity of the light irradiation device.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a light irradiation device that is configured to cover the entire light irradiation device with a housing, yet can efficiently cool the light-emitting elements and driving substrate and suppress a rise in temperature of the housing. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the light irradiation device of the present invention comprises a light source module having a substrate and a light-emitting element mounted on a first surface of the substrate, a heat sink arranged to abut against a second surface of the substrate, a circuit board or circuit wiring electrically connected to the light source module, and a housing having a first space in which the heat sink is housed and a second space in which the circuit board or circuit wiring is housed, and is characterized in that the housing is provided with a first opening connecting the first space to the outside of the housing, a second opening connecting the second space to the outside of the housing, and a third opening connecting the first space to the second space.

[0009] Moreover, it is preferable that the housing has a partition plate that separates the first space and the second space, and that the third opening is provided in the partition plate.

[0010] Also, the heat sink is preferably disposed between the first opening and the third opening.

[0011] Also, it is preferable that the circuit board or the circuit wiring is disposed between the second opening and the third opening.

[0012] It is also preferable to further include a dry air generator that reduces the amount of water vapor in the input air to generate dry air and supplies the generated dry air to the first opening.

[0013] In addition, it is preferable that a flow path is provided within the heat sink through which a coolant selected from the group consisting of water, ethylene glycol, propylene glycol, and mixtures of these with water flows.

[0014] In addition, it is preferable that the circuit board or the circuit wiring is a member that supplies power to the light source module or controls the light source module.

[0015] Moreover, it is preferable that the light emitting element emits light of a wavelength that acts on the ultraviolet curing resin. Effect of the Invention

[0016] As described above, according to the present invention, a light irradiation device is realized that can efficiently cool the light-emitting elements and driving substrate and suppress a rise in temperature of the housing, even while adopting a configuration in which the entire light irradiation device is covered with a housing. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an external appearance of a light irradiation device according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating an internal configuration of a light irradiation device according to an embodiment of the present invention. [Diagram 3] 2A to 2C are diagrams illustrating a configuration of a light irradiation unit mounted on the light irradiation device according to the embodiment of the present invention. [Figure 4] 5A to 5C are diagrams illustrating an internal configuration of a heat sink mounted on the light irradiation device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0019] FIG. 1 is a diagram for explaining the appearance of a light irradiation device 1 according to an embodiment of the present invention, in which FIG. 1(a) is a top view, FIG. 1(b) is a front view, FIG. 1(c) is a bottom view, FIG. 1(d) is a left side view, and FIG. 1(e) is a right side view. FIG. 2 is a diagram for explaining the internal configuration of the light irradiation device 1 according to an embodiment of the present invention, and is a cross-sectional view cut along line XX in FIG. 1. In FIG. 2, the configuration of a dry air generator 400 connected to the light irradiation device 1 is also shown diagrammatically, and the dashed line in FIG. 2 indicates the flow of dry air generated by the dry air generator 400.

[0020] The light irradiation device 1 of this embodiment is a device mounted on a light source device that cures ultraviolet curable ink used as printing ink and ultraviolet curable resin used as a sealant in FPD (Flat Panel Display) and the like, and is disposed facing an irradiation object (not shown) and emits ultraviolet light toward a predetermined area of ​​the irradiation object. The light irradiation device 1 of this embodiment is connected to a dry air generator 400, and the dry air generated by the dry air generator 400 is supplied into the housing 300 of the light irradiation device 1.

[0021] 1 and 2, the light irradiation device 1 is composed of a light irradiation unit 100 that emits ultraviolet light, a control circuit board 200 (circuit board or circuit wiring) electrically connected to the light irradiation unit 100, and a housing 300 that houses the light irradiation unit 100 and the control circuit board 200. Hereinafter, in this specification, the longitudinal direction (i.e., the left-right direction in FIG. 1(b)) of the ultraviolet light emitted from the light irradiation device 1 is defined as the X-axis direction, the lateral direction (i.e., the up-down direction in FIG. 1(b)) as the Y-axis direction, and the direction perpendicular to the X-axis and Y-axis as the Z-axis direction.

[0022] 1, an opening 312 is formed in a front surface 310, and a glass window 314 is attached to the opening 312. A refrigerant supply port 322 and an exhaust port 324 are provided in an upper surface 320 of the housing 300. An air intake port 332 (first opening) through which dry air is supplied from the dry air generator 400, and an air exhaust port 334 (second opening) through which air inside the housing 300 is exhausted are provided in a left side surface 330 of the housing 300. Power connectors 342 and 344 that are connected to an external power supply device (not shown) and supply power to the control circuit board 200 are provided in a right side surface 340 of the housing 300.

[0023] 2, a partition plate 350 is provided inside the housing 300 to divide the inside of the housing 300 into two spaces in the Z-axis direction, and the partition plate 350 divides the inside of the housing 300 into a first storage section 360 (first space) that stores the light irradiation unit 100 and a second storage section 370 (second space) that stores the control circuit board 200. A through hole 352 (third opening) that connects the first storage section 360 and the second storage section 370 is provided at an end of the partition plate 350 in the X-axis direction, and the dry air that has entered the housing 300 is supplied to the second storage section 370 via the through hole 352 through the first storage section 360 (details will be described later). In this embodiment, air intake port 332 penetrates left side surface 330 of housing 300 so as to connect first storage section 360 to the outside of housing 300, and air exhaust port 334 penetrates left side surface 330 of housing 300 so as to connect second storage section 370 to the outside of housing 300.

[0024] Fig. 3 is a plan view illustrating the configuration of the light irradiation unit 100. As shown in Fig. 3, the light irradiation unit 100 includes a light source module 110 and a heat sink 120. The light source module 110 is a unit that emits ultraviolet light toward an irradiation object and irradiates a predetermined area of ​​the irradiation object in a rectangular shape, and in this embodiment, is placed on and fixed to the heat sink 120.

[0025] The light source module 110 includes a rectangular LED substrate 112 on which a plurality of wiring patterns 112a to 112e are formed, and a plurality of LED elements 114 (light-emitting elements) arranged on a surface (first surface) of the LED substrate 112. As shown in Fig. 3, the light source module 110 of this embodiment is fixed to a heat sink 120 by six fixing screws 116 inserted into the LED substrate 112. Note that it is preferable to use a ceramic substrate or the like formed of aluminum nitride having high thermal conductivity as the LED substrate 112.

[0026] The LED elements 114 are, for example, LED chips that emit ultraviolet light, and in this embodiment, three LED elements 114 are arranged on each of the wiring patterns 112a to 112d, that is, four LED elements (X-axis direction) by three LED elements (Y-axis direction) in total, at predetermined intervals in the X-axis direction and the Y-axis direction. The anode terminal of each LED element 114 is die-bonded to the wiring pattern 112a to 112d directly below, and the cathode terminal is electrically connected to each of the adjacent wiring patterns 112b to 112e by the bonding wire 115. That is, in this embodiment, three LED elements 114 arranged in the Y-axis direction on each of the wiring patterns 112a to 112d are electrically connected in parallel, and the wiring patterns 112a to 112e are electrically connected in series by the bonding wire 115. In addition, an anode terminal 117 (positive terminal) electrically connected to the control circuit board 200 (Figure 2) is fastened to the wiring pattern 112a by a fixing screw 116, and a cathode terminal 118 (negative terminal) electrically connected to the control circuit board 200 is fastened to the wiring pattern 112e by a fixing screw 116.

[0027] The control circuit board 200 (FIG. 2) is electrically connected to an external power supply (not shown) via power connectors 342, 344, and is a member that generates a drive current for the LED elements 114 of the light source module 110 using power from the power supply (i.e., supplies power to the light source module 110) or controls the drive current (i.e., controls the light source module 110). The control circuit board 200 may be a circuit component in various forms, such as a board shape or an element shape, or may be a wiring member (circuit wiring) such as a wire. 2, the control circuit board 200 of this embodiment is disposed between the air exhaust port 334 and the through hole 352, and is fixed to the rear surface (the surface opposite to the light source module 110) of the partition plate 350. In order to make the drawing easier to see, wires connecting the control circuit board 200 to the power connectors 342, 344 and wires connecting the control circuit board 200 to the anode terminal 117 and the cathode terminal 118 are omitted in FIG.

[0028] As shown in Fig. 3, when a drive current (i.e., an anode current) is supplied from the control circuit board 200 to the anode terminal 117 connected to the wiring pattern 112a, the drive current flows through all the LED elements 114 arranged on the wiring patterns 112a to 112d, and each LED element 114 emits ultraviolet light of an amount of light according to the drive current. In this embodiment, each LED element 114 has substantially the same electrical characteristics, and is configured to emit ultraviolet light of substantially the same irradiation intensity distribution. The drive current flowing through each LED element 114 passes through the wiring pattern 112e, and a return current (i.e., a cathode current) is returned from the cathode terminal 118 connected to the wiring pattern 112e toward the control circuit board 200.

[0029] In this way, when a drive current flows through all the LED elements 114 mounted on the light source module 110 and ultraviolet light is emitted from each LED element 114, the temperature rises due to self-heating of the LED elements 114, causing a problem of a significant drop in light emission efficiency. For this reason, in this embodiment, a heat sink 120 is provided in close contact with the light source module 110, and the heat generated by the LED elements 114 is forcibly dissipated.

[0030] The heat sink 120 is a member for fixing the light source module 110 and dissipating heat generated by the light source module 110, and is made of a metal such as copper having high thermal conductivity. As shown in Figs. 2 and 3, the heat sink 120 is a rectangular flat plate-shaped member, and the front surface (surface on the Z-axis direction + side) of the heat sink 120 is a mounting surface for the light source module 110 (that is, it is adapted to abut against the rear surface (second surface) of the LED substrate 112) (Figs. 2 and 3). As shown in Fig. 2, the heat sink 120 is disposed between the air intake port 332 and the through hole 352, and the bottom surface of the heat sink 120 is fixed to the partition plate 350 of the housing 300 by a plurality of fixing screws (not shown).

[0031] Fig. 4 is a diagram for explaining the internal configuration of the heat sink 120, and is a cross-sectional view taken along line YY in Fig. 1. The heat sink 120 of this embodiment is a so-called water-cooled heat sink, and as shown in Fig. 4, a cylindrical flow path 122 through which a refrigerant flows is formed inside the heat sink 120 in a serpentine manner from a supply port 322 to a discharge port 324. The refrigerant used is water, ethylene glycol, propylene glycol, or a mixture of these with water.

[0032] As described above, in this embodiment, as shown in FIG. 2, the light irradiation unit 100 is accommodated in the housing 300, but there is a problem that the temperature of the housing 300 itself rises because part of the ultraviolet light from the LED element 114 hits the inner surface of the housing 300 and is repeatedly reflected inside the housing 300. In addition, when the light irradiation device 1 is used in a high-humidity environment, there is a problem that high-humidity air cannot be prevented from entering the housing 300, and when the high-humidity air enters the housing 300 and touches the cooled heat sink 120 and its surroundings, condensation occurs. In addition, even if the environment is not high-humidity, if a coolant flows through the heat sink 120 while the LED element 114 is not lit, the heat sink 120 and its surroundings are excessively cooled, and condensation occurs in the heat sink 120 and its surroundings. In order to solve such problems, the light irradiation device 1 of this embodiment is configured to generate dry air by the dry air generator 400 and supply the dry air into the housing 300 that houses the light irradiation unit 100, the heat sink 120, and the control circuit board 200. The dry air from the dry air generator 400 is always supplied into the housing 300 (at least when a refrigerant flows through the heat sink 120 (i.e., when the heat sink 120 is being cooled)) regardless of whether the LED elements 114 are lit or not.

[0033] As described above, the left side surface 330 of the housing 300 of the light irradiation device 1 of this embodiment is provided with the air intake port 332, and the dry air generator 400 is connected to the air intake port 332 (FIG. 2). Compressed air from an external air compressor (air supply device) is forced to pass through the dry air generator 400 and the air intake port 332 and be supplied to the first storage section 360 of the housing 300.

[0034] The dry air generator 400 of this embodiment is a device that generates dry air (i.e., dehumidified air) from input compressed air, and as shown in FIG. 2, is composed of an air filter 410, a mist filter 420, a dryer 430, a regulator 440, a flow valve 450, etc.

[0035] The air filter 410 is a filter for removing foreign matter such as dust and dirt from the compressed air input from the air compressor. The mist filter 420 is a filter for removing oil mist and the like (fine particles) contained in the compressed air that has passed through the air filter 410. The dryer 430 is a device for drying the compressed air that has passed through the mist filter 420 (reducing the amount of water vapor in the compressed air), and for example, a so-called refrigerant condenser or the like is used, which is configured by folding back a metal pipe through which a refrigerant flows in a serpentine shape. The regulator 440 is a device for reducing the pressure of the compressed air that has passed through the dryer 430. The flow rate valve 450 is a device for adjusting the flow rate of the compressed air supplied from the dry air generator 400 to the housing 300.

[0036] In this way, the compressed air input to the dry air generator 400 passes through the air filter 410, the mist filter 420, the dryer 430, the regulator 440, and the flow valve 450 in this order, thereby generating clean, dry air, which is supplied at a predetermined pressure and flow rate to the first housing section 360 of the housing 300 via the air intake port 332. In this specification, dry air refers to air with a lower humidity (lower water vapor content) than the compressed air input to the dry air generator 400, for example, air with a dew point of -20° or lower (atmospheric pressure, air humidity of 5% or lower, air temperature of 0°).

[0037] As described above, in this embodiment, the compressed air generated by the dry air generator 400 is forcibly supplied to the first storage section 360 of the housing 300, so that the dry air supplied to the first storage section 360 first flows through the space in which the light irradiation unit 100 (i.e., the light source module 110 and the heat sink 120) of the first storage section 360 is arranged. Then, when the first storage section 360 is filled with dry air, the dry air in the first storage section 360 is pushed out from the through hole 352 provided in the partition plate 350 into the second storage section 370. Then, as a result of the dry air in the first storage section 360 being pushed out one after another into the second storage section 370, the dry air supplied to the second storage section 370 flows through the space in which the control circuit board 200 is arranged, and is exhausted from the air exhaust port 334 formed on the left side surface 330 of the housing 300.

[0038] In this way, the dry air generated by the dry air generator 400 is supplied to the first storage section 360, flows through the first storage section 360 toward the through hole 352 (i.e., along the X-axis direction), flows from the through hole 352 into the second storage section 370, flows through the second storage section 370 toward the air exhaust port 334 (i.e., in the direction opposite to the X-axis direction), and is exhausted to the outside. In this embodiment, the flow rate is controlled so that the amount of compressed air introduced from the dry air generator 400 into the first storage section 360 of the housing 300 is greater than the amount of dry air exhausted to the outside from the air exhaust port 334, so that the first storage section 360 and the second storage section 370 are always filled with dry air. Therefore, even if the air (i.e., dry air) in the first storage section 360 is cooled by the heat sink 120, condensation does not occur.

[0039] Furthermore, the dry air in the first housing section 360 is cooled by the heat sink 120 arranged in the first housing section 360, so that the first housing section 360 is filled with cooled dry air. As a result, the housing 300 itself is cooled by the cooled dry air filling the first housing section 360, and even if part of the ultraviolet light from the LED elements 114 hits the inner surface of the housing 300 and the temperature of the housing 300 rises, the housing 300 can be cooled efficiently.

[0040] Furthermore, the dry air in the first accommodating section 360 is cooled by the heat sink 120 disposed in the first accommodating section 360, and the cooled dry air is supplied to the second accommodating section 370. Therefore, the control circuit board 200 disposed in the second accommodating section 370 is efficiently cooled by the cooled dry air.

[0041] In this manner, the light irradiation device 1 of the present embodiment is configured to introduce dry air from the dry air generator 400 into the housing 300, and to allow the dry air to flow constantly (at least when the refrigerant flows through the heat sink 120) through the first housing section 360 in which the light irradiation unit 100 (i.e., the light source module 110 and the heat sink 120) is disposed, and the second housing section 370 in which the control circuit board 200 is disposed. The configuration in which the periphery of the light irradiation unit 100 is filled with dry air suppresses or prevents the occurrence of condensation on the heat sink 120. The configuration in which the periphery of the control circuit board 200 is filled with dry air cooled by the heat sink 120 also suppresses an increase in the temperature of the control circuit board 200. That is, the light irradiation device 1 of this embodiment has a configuration in which the light irradiation unit 100 (i.e., the light source module 110 and the heat sink 120) and the control circuit board 200 are covered by the housing 300, and the humidity inside the housing 300 (i.e., the first housing section 360 and the second housing section 370) is always kept low and not high in temperature. Therefore, according to the configuration of this embodiment, the LED elements 114 on the LED board 112 are not shorted out by water droplets due to condensation, the electronic components on the control circuit board 200 are not shorted out, and the ion migration of the patterns on the LED board 112 and the control circuit board 200 is not accelerated. In addition, since the housing 300 is filled with cooled dry air, the increase in temperature of the housing 300 is also suppressed.

[0042] Although the present embodiment has been described above, 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.

[0043] For example, in the present embodiment, the inside of the housing 300 is described as being separated by the partition plate 350 into a first housing section 360 housing the light irradiation unit 100 and a second housing section 370 housing the control circuit board 200, but the present invention is not necessarily limited to such a configuration, and the light irradiation unit 100 and the control circuit board 200 may be disposed in one housing section in the housing 300. In this case, it is preferable that the dry air flows in order through the space in which the light irradiation unit 100 is disposed and the space in which the control circuit board 200 is disposed.

[0044] In addition, in this embodiment, the dry air flows through the first storage section 360 and then the second storage section 370, but this is not necessarily limited to such a configuration, and the dry air may flow through the second storage section 370 and then the first storage section 360 (i.e., in the opposite direction).

[0045] In the present embodiment, the dry air is generated by the dry air generator 400 which is separate from the light irradiation device 1. However, the dry air generator 400 may be integrated into the light irradiation device 1. Furthermore, if sufficiently dry compressed air can be supplied to the light irradiation device 1, the dry air generator 400 is not necessarily required.

[0046] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0047] 1:Light irradiation device 100: Light irradiation unit 110: Light source module 112: LED board 112a: Wiring pattern 112b: Wiring pattern 112c: Wiring pattern 112d: Wiring pattern 112e: Wiring pattern 114: LED element 115: Bonding wire 116: Fixing screw 117: Anode terminal 118: Cathode terminal 120: Heat sink 122: Flow path 200: Control circuit board 300: Housing 310:Front 312 :Aperture 314: Window section 320:Top surface 322: Supply port 324: Outlet 330: Left side 332: Air intake 334: Air exhaust port 340: Right side 342: Power connector 344: Power connector 350: Partition plate 352:Through hole 360: First storage section 370: Second storage section 400: Dry air generator 410: Air filter 420: Mist filter 430: Dryer 440: Regulator 450: Flow valve

Claims

1. a light source module having a substrate and a light emitting element mounted on a first surface of the substrate; a heat sink provided to abut against the second surface of the substrate; A circuit board or circuit wiring electrically connected to the light source module; a housing having a first space in which the heat sink is housed and a second space in which the circuit board or the circuit wiring is housed; Equipped with The housing is provided with a first opening connecting the first space to an outside of the housing, a second opening connecting the second space to an outside of the housing, and a third opening connecting the first space to the second space. A light irradiation device characterized by:

2. the housing has a partition plate that separates the first space and the second space, The light irradiation device according to claim 1 , wherein the third opening is provided in the partition plate.

3. The light irradiation device according to claim 1 , wherein the heat sink is disposed between the first opening and the third opening.

4. The light irradiation device according to claim 1 , wherein the circuit board or the circuit wiring is disposed between the second opening and the third opening.

5. 2. The light irradiation device according to claim 1, further comprising a dry air generator that reduces an amount of water vapor in input air to generate dry air and supplies the generated dry air to the first opening.

6. 2. The light irradiation device according to claim 1, wherein a flow path is provided in the heat sink through which a coolant selected from the group consisting of water, ethylene glycol, propylene glycol, and mixtures of these with water flows.

7. 2. The light irradiation device according to claim 1, wherein the circuit board or the circuit wiring is a member that supplies power to the light source module or controls the light source module.

8. 2. The light irradiation device according to claim 1, wherein the light emitting element emits light having a wavelength that acts on an ultraviolet curing resin.

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