JP2013030574A - Optical irradiation device, optical irradiation module and printer - Google Patents

Abstract

【Task】
Provided is a light irradiation device that realizes a relatively high ultraviolet irradiation energy without being affected by the heat generated by the ultraviolet light emitting element itself even if the mounting density of the ultraviolet light emitting elements is relatively high.
[Solution]
A plurality of first light emitting elements; a first substrate having a plurality of openings each having at least one of the plurality of first light emitting elements disposed on one main surface; a plurality of second light emitting elements; And a second substrate on which the plurality of second light emitting elements are arranged. The second substrate is made of a material that transmits light emitted from the first light emitting element, and is disposed to cover at least one of the plurality of openings with the other main surface, and the plurality of second light emitting elements Is disposed in a region other than the region corresponding to the opening. In addition, a heat radiating portion is provided between the first substrate and the second substrate or in the second substrate.
[Selection] Figure 2

Description

  The present invention relates to a light irradiation device, a light irradiation module, and a printing apparatus used for curing an ultraviolet curable resin or a paint.

  2. Description of the Related Art Conventionally, ultraviolet irradiation apparatuses are widely used for the purpose of fluorescence reaction observation in medical and bio fields, sterilization applications, adhesion of electronic components, curing of ultraviolet curable resins and inks, and the like. A high-pressure mercury lamp is used as a lamp light source for UV irradiation devices used for curing UV curable resins used for bonding small parts in the field of electronic components, etc., and UV curable ink used for printing. And metal halide lamps are used.

  In recent years, there has been a strong desire to reduce the global environmental load on a global scale, and there has been an active movement to adopt an ultraviolet light emitting element as a lamp light source capable of suppressing the generation of ozone with a relatively long life, energy saving. .

  However, since the illuminance of the ultraviolet light emitting element is relatively low, for example, as described in Patent Document 1, a device in which a plurality of light emitting elements are mounted on one substrate is prepared, and the plurality of devices are mounted on a support. The module of the structure is generally used, and the ultraviolet irradiation energy necessary for the effect of the ultraviolet curable ink is secured.

  However, there is an increasing demand for improvement in ultraviolet irradiation energy, and attempts have been made to increase the mounting density of the ultraviolet light emitting elements. However, although the heat generation from the ultraviolet light emitting elements is relatively small, A device with a higher mounting density has a problem that heat radiation cannot be sufficiently performed, which hinders improvement of ultraviolet irradiation energy.

JP 2008-244165 A

  The present invention has been made in view of the above problems, and realizes relatively high UV irradiation energy by efficiently dissipating the heat generated from the UV light emitting elements even if the mounting density of the UV light emitting elements is relatively high. An object of the present invention is to provide a light irradiation device, a module, and a printing apparatus.

  The light irradiation device according to the present invention includes a plurality of first light emitting elements, a first substrate having a plurality of openings each having at least one of the plurality of first light emitting elements arranged on one main surface, and a plurality of first light emitting elements. And a second substrate having the plurality of second light emitting elements arranged on one main surface, the second substrate being made of a material that transmits light emitted from the first light emitting element. And at least one of the plurality of openings is disposed to cover the other main surface, and the plurality of second light emitting elements are disposed in a region other than the region corresponding to the opening, A heat dissipation portion is provided between or on the second substrate or on the second substrate.

  The heat dissipating part may include a flow path through which a coolant can flow inside the second substrate.

  Furthermore, the heat radiating part includes a flow path through which a coolant can flow between the first substrate and the second substrate.

  Further, a metal layer is formed in a region other than a region corresponding to the opening in at least one of the one main surface and the other main surface of the second substrate.

  Further, the wavelength of the light emitted from the first light emitting element is different from the wavelength of the light emitted from the second light emitting element.

  Further, the thermal conductivity of the first substrate is different from the thermal conductivity of the second substrate, and the wavelength of light emitted from the light emitting element disposed on the substrate having the higher thermal conductivity is disposed on the other substrate. It is characterized by being shorter than the wavelength of light emitted by the light emitting element.

  Furthermore, a light irradiation module is provided, in which a plurality of the above-described light irradiation devices are placed on a heat radiating member.

  Also provided is a printing apparatus comprising: a printing unit that performs printing on a recording medium; and the above-described light irradiation module that irradiates the printed recording medium with light.

  According to the light irradiation device of the present invention, a plurality of first light emitting elements, a first substrate having a plurality of openings each having at least one of the plurality of first light emitting elements disposed on one main surface, A second light-emitting element; and a second substrate on which the plurality of second light-emitting elements are arranged on one main surface. The second substrate is made of a material that transmits light emitted from the first light emitting element, and is disposed to cover at least one of the plurality of openings with the other main surface, and the plurality of second light emitting elements Is disposed in a region other than the region corresponding to the opening. In addition, a heat radiating portion is provided between the first substrate and the second substrate or in the second substrate. Therefore, each heat generated by the plurality of first light emitting elements and the plurality of second light emitting elements is radiated well, and the amount of heat transmitted from each light emitting element to the second substrate and the first substrate is reduced. Since the first substrate and the second substrate are well prevented from becoming excessively hot, the heat dissipation of the first substrate is maintained high.

  Therefore, according to the light irradiation device of the present embodiment, even if the mounting density of the ultraviolet light emitting elements is relatively high, it is hardly affected by the heat generated by the ultraviolet light emitting elements themselves and realizes a relatively high ultraviolet irradiation energy. A light irradiation device is realized.

FIG. 1 is a plan view of a light irradiation device according to an embodiment of the present invention. 2A is a cross-sectional view taken along line 1I-1I in the light irradiation device shown in FIG. FIG. 2B is a cross-sectional view taken along line 1II-1II in the light irradiation device shown in FIG. FIG. 3 is a plan view of a light irradiation module using the light irradiation device shown in FIG. 4A is a cross-sectional view of the light irradiation module shown in FIG. 3 taken along line 3I-3I. FIG. 4B is a cross-sectional view taken along the line 3II-3II of the light irradiation module shown in FIG. FIG. 5 is a top view of a printing apparatus using the light irradiation module shown in FIG. 6 is a side view of the printing apparatus shown in FIG. FIG. 7 is a plan view showing a first modification of the light irradiation device shown in FIG. FIG. 8 is a cross-sectional view showing a second modification of the light irradiation device shown in FIG. Fig.9 (a) is a top view of the 2nd board | substrate which comprises the light irradiation device shown in FIG. FIG. 9B is a cross-sectional view taken along the line 9I-9I in FIG. FIG. 10 is a plan view showing a third modification of the light irradiation device shown in FIG. Fig.11 (a) is sectional drawing along the 10I-10I line | wire of the light irradiation device shown in FIG. FIG.11 (b) is sectional drawing along the 10II-10II line | wire of the light irradiation device shown in FIG. FIG. 12 shows a fourth modification of the light irradiation device shown in FIG. Fig.13 (a) is sectional drawing along the 12I-12I line | wire of the light irradiation device shown in FIG. FIG. 13B is a cross-sectional view taken along line 12II-12II of the light irradiation device shown in FIG. FIG. 14 shows a fifth modification of the light irradiation device shown in FIG. Fig.15 (a) is sectional drawing along the 14I-14I line | wire of the light irradiation device shown in FIG. FIG.15 (b) is sectional drawing along the 14II-14II line | wire of the light irradiation device shown in FIG.

  Hereinafter, a light irradiation device, a light irradiation module, and a printing apparatus of the present invention will be described with reference to the drawings.

(Embodiment of light irradiation device)
The light irradiation device 1 shown in FIGS. 1 and 2 is incorporated in a printing apparatus such as an offset printing apparatus or an inkjet printing apparatus that uses ultraviolet curable ink, and the ultraviolet curable ink is deposited on an object (recording medium). It functions as an ultraviolet light generation light source of an ultraviolet irradiation module that cures the ultraviolet curable ink by irradiating ultraviolet rays later.

  The light irradiation device 1 includes a first substrate 10 having a plurality of openings 12 on one main surface 11 a, a plurality of connection pads 13 provided in each opening 12, and each opening 12 in the first substrate 10. A plurality of first light emitting elements 30a electrically connected to the connection pads 13, a plurality of sealing materials 40 filled in the respective openings 12 and covering the first light emitting elements 30a, and each opening. A flow path 80 in which a refrigerant disposed on one main surface 11a of the first substrate 10 via a first adhesive 71 so as to cover the first light emitting element 30a corresponding to the portion 12 can flow therein. Are disposed in a region other than the region corresponding to the opening 12 of the first substrate 10 on the second substrate 20 and the connection pads 23 provided on the second substrate 20. A plurality of second light emitting elements 30b electrically connected to the pads 23; To have. Here, the region other than the region corresponding to the opening 12 of the first substrate 10 corresponds to the one main surface 11a of the first substrate 10, and the second light emitting element 30b is seen through from the second substrate side, and is opened. It will be located on the one principal surface 11a other than the part 12.

  The first substrate 10 includes a stacked body 50 in which a first insulating layer 51 and a second insulating layer 52 are stacked, and a first electric wiring 61 that connects the first light emitting elements 30a to each other. The first light emitting element 30a is supported in the opening 12 provided on the one main surface 11a. In the case of the present embodiment, four first light emitting elements 30 a are arranged in the opening 12.

  The first insulating layer 51 includes, for example, an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, ceramics such as glass ceramics, and resins such as epoxy resins and liquid crystal polymers (LCP). , Etc.

Next, the first electrical wiring 61 is formed in a predetermined pattern from a conductive material such as tungsten (W), molybdenum (Mo), manganese (Mn), copper (Cu), and the like. It functions as a power supply wiring for supplying a current to the element 30a or a current from the first light emitting element 30a.

  Next, in the second insulating layer 52 laminated on the first insulating layer 51, an opening 12 that penetrates the second insulating layer 52 is formed.

  The opening 12 has an inner peripheral surface 14 inclined such that each opening has a larger opening area on the one main surface 11a side of the first substrate 10 than the mounting surface of the first light emitting element 30a. When viewed in plan, for example, it has a substantially circular shape. The opening shape is not limited to a circular shape, and may be a substantially rectangular shape.

  Such an opening 12 has a function of reflecting light emitted from the first light emitting element 30a upward on the inner peripheral surface 14 to improve light extraction efficiency.

  In order to improve the light extraction efficiency, as the material of the second insulating layer 52, a porous ceramic material having relatively good reflectivity with respect to light in the ultraviolet region, such as an aluminum oxide sintered body, oxidation It is preferable to form with a zirconium sintered body and an aluminum nitride sintered body. Further, from the viewpoint of improving the light extraction efficiency, a metal reflection film may be provided on the inner peripheral surface 14 of the opening 12.

  Such openings 12 are arranged vertically and horizontally over the entire main surface 11 a of the first substrate 10. For example, in this embodiment, they are arranged in a regular lattice.

  In the light irradiation device 1 according to the present embodiment, the arrangement shape of the openings 12 is a regular lattice shape, but may be arranged in a staggered lattice shape. It becomes possible to arrange them at a high density, and the illuminance per unit area can be made relatively high. Here, to arrange in a zigzag pattern is synonymous with arranging at the grid points of the diagonal grid.

  As a matter of course, the light outputs of the plurality of first light emitting elements 30a of the present embodiment have substantially the same value. For example, the variation in the light output as a whole of the plurality of first light emitting elements 30a of the present embodiment is within 10%.

  In the first substrate 10 including the laminate 50 including the first insulating layer 51 and the second insulating layer 52 as described above, the first insulating layer 51 and the second insulating layer 52 are made of ceramics or the like. In this case, it is manufactured through the following steps. First, a plurality of ceramic green sheets manufactured by a conventionally known method is prepared. A hole corresponding to the opening is formed in the ceramic green sheet corresponding to the opening 12 by a method such as punching. Next, a metal paste to be the first electric wiring 61 is printed (not shown) on the green sheet, and then the green sheet is laminated so that the printed metal paste is positioned between the green sheets. Examples of the metal paste used as the first electric wiring 61 include a paste containing a metal such as tungsten (W), molybdenum (Mo), manganese (Mn), and copper (Cu). Next, the first substrate 10 having the first electrical wiring 61 and the opening 12 can be formed by firing the laminate and firing the green sheet and the metal paste together.

Moreover, when the 1st insulating layer 51 and the 2nd insulating layer 52 consist of resin, the following methods can be considered as the manufacturing method of the 1st board | substrate 10, for example. First, a precursor sheet of a thermosetting resin is prepared. Next, a plurality of precursor sheets are laminated so that lead terminals made of a metal material to be the first electric wiring 61 are disposed between the precursor sheets and the lead terminals are embedded in the precursor sheets. Examples of the material for forming the lead terminal include metal materials such as Cu, Ag, Al, iron (Fe) -nickel (Ni) -cobalt (Co) alloy, and Fe-Ni alloy. And after forming the hole corresponding to the opening part 12 in a precursor sheet | seat by methods, such as a laser processing and an etching, the 1st board | substrate 10 is completed by thermosetting this.

  On the other hand, in the opening 12 of the first substrate 10, a connection pad 13 electrically connected to the first light emitting element 30a, and solder, gold (Au) wire, aluminum (Al) wire, etc. to the connection pad 13 are provided. The first light emitting element 30a connected by the bonding material 15 and the sealing material 40 for sealing the first light emitting element 30a are provided.

  The connection pad 13 is formed of a metal layer made of a metal material such as tungsten (W), molybdenum (Mo), manganese (Mn), and copper (Cu). If necessary, a nickel (Ni) layer, a palladium (Pd) layer, a gold (Au) layer, or the like may be further laminated on the metal layer. The connection pad 13 is connected to the first light emitting element 30a by a bonding material 15 such as solder, gold (Au) wire, or aluminum (Al) wire.

  The first light emitting element 30a includes, for example, a light emitting diode in which a p-type semiconductor layer and an n-type semiconductor layer made of a semiconductor material such as GaAs or GaN are stacked on a first element substrate 31a such as a sapphire substrate, The semiconductor layer is composed of an organic EL element made of an organic material.

  The first light emitting element 30a includes a first semiconductor layer 32a having a light emitting layer and a connecting pad 15 disposed on the first substrate 10 and a bonding material 15 such as solder, gold (Au) wire, aluminum (Al) wire, or the like. The first element electrodes 33 a and 34 a made of a metal material such as Ag are connected via a wire, and are wire-bonded to the first substrate 10. The first light emitting element 30a emits light having a predetermined wavelength according to the current flowing between the first element electrodes 33a and 34a with a predetermined luminance, and the light is transmitted through the first element substrate 31a or Directly exits to the outside. As is well known, the first element substrate 31a can be omitted. Further, the connection between the first element electrodes 33a, 34a of the first light emitting element 30a and the connection pad 13 may be performed by a conventionally known flip lip connection technique using solder or the like as the bonding material 15.

  In the present embodiment, an LED that emits UV light whose wavelength peak of light emitted from the first light emitting element 30a is, for example, 250 to 395 [nm] or less is employed. That is, in the present embodiment, a UV-LED element is employed as the first light emitting element 30a. The first light emitting element 30a is formed by a conventionally known thin film forming technique.

  And this 1st light emitting element 30a is sealed with the sealing material 40 mentioned above.

  The sealing material 40 is formed of an insulating material such as a light-transmitting resin material, and prevents the entry of moisture from the outside by sealing the first light emitting element 30a well, The first light emitting element 30a is protected by absorbing the impact from the light.

  The sealing material 40 has a refractive index between the refractive index of the first element substrate 31a constituting the first light emitting element 30a (1.7 for sapphire) and the refractive index of air (about 1.0). The light extraction efficiency of the first light emitting element 30a can be improved by forming it from a material such as a silicone resin (refractive index: about 1.4).

  The sealing material 40 is formed by mounting the first light emitting element 30a on the first substrate 10, filling the opening 12 with a precursor such as silicone resin, and curing the precursor.

  Next, the second substrate 20 is disposed on the one main surface 11a of the first substrate 10 via the first adhesive 71 so as to cover the plurality of openings 12 of the first substrate 10. ing. In the present embodiment, the areas of the first substrate 10 and the second substrate 20 in plan view are substantially equal. In addition, the 2nd board | substrate 20 does not necessarily need to cover the 1st board | substrate whole, What is necessary is just to change a magnitude | size and the position arrange | positioned as needed.

  The second substrate 20 is made of a light transmissive material, for example, soda lime glass, sapphire glass or quartz glass, low alkali borosilicate glass, silica glass or zirconia that transmits ultraviolet light emitted from the first light emitting element 30a. And heat-resistant glass such as super heat-resistant crystallized glass containing the above crystal nucleating agent.

  A flow path 80 through which a coolant can flow is formed inside the second substrate 20. In the present embodiment, the flow path 80 is formed over substantially the entire area of the second substrate 20 in plan view. An entrance and an exit of a flow path are provided at both ends of one end of the second substrate 20, and a flow path having a width approximately half that of the second substrate is formed from the entrance toward the inside of the second substrate 20. The channel is formed so as to be folded back on the part side and connected to the outlet.

  Heat generated by the plurality of second light emitting elements 30b is caused to flow through the flow path 80 by flowing a refrigerant such as a gas refrigerant such as carbon dioxide, nitrogen or helium, or a liquid refrigerant such as water, liquefied nitrogen, or acetone. Heat can be radiated from the second substrate 20. That is, the flow path 80 functions as a heat radiating part that radiates heat generated by the plurality of second light emitting elements 30b.

  In addition, it is preferable that the thermal conductivity of the material which comprises a 2nd board | substrate is lower than the thermal conductivity of the material which comprises a 1st board | substrate. This is because if the thermal conductivity of the second substrate is low, it is possible to suppress the diffusion of heat to the first substrate.

  In addition, when a resin such as an epoxy resin or a silicone resin is employed for the first adhesive 71, the first adhesive 71 also functions as a heat insulating material that thermally separates the first substrate 10 and the second substrate 20. Therefore, it is preferable. When the first adhesive is a light transmissive resin such as an epoxy resin or a silicone resin, the first adhesive 71 can be applied so as to cover the opening 12 of the first substrate 10. preferable. As a matter of course, when a material that does not transmit light is used as the first adhesive 71, the first adhesive 71 is not applied onto the opening 12 of the first substrate.

  The second substrate 20 is connected to the connection pad 23 electrically connected to the second light emitting element 30b and to the connection pad 23 by a bonding material 15 such as solder, gold (Au) wire, aluminum (Al) wire, or the like. A second light emitting element 30b is provided. The second light emitting elements 30 b are connected by a second electric wiring 62.

  Here, the second electric wiring 62 is formed by a conventionally known photolithography method or the like. That is, the metal material is formed as a metal film on the one principal surface 21a of the second substrate 20 by sputtering, vapor deposition, or chemical vapor deposition. A photosensitive resin is applied to the surface of the metal film, and a pattern having a desired shape is formed on the photosensitive resin by performing exposure processing and development processing on the applied photosensitive resin. Next, the metal film is etched with a chemical solution to make the metal film into a desired shape, and then the applied photosensitive resin is peeled off. Thus, the second electrical wiring 62 can be formed by forming and patterning a metal material.

Similarly to the first light emitting element 30a, the second light emitting element 30b has, for example, a p-type semiconductor layer and an n-type semiconductor layer made of a semiconductor material such as GaAs or GaN on the first element substrate 31a such as a sapphire substrate. Light-emitting diodes that are stacked and organic ELs that have semiconductor layers made of organic materials
It is comprised by the element etc.

  The second light emitting element 30b includes a bonding material 15 such as solder, gold (Au) wire, aluminum (Al) wire, etc., on the second semiconductor layer 32b having a light emitting layer and the connection pad 23 disposed on the second substrate 10. The second element electrodes 33b and 34b made of a metal material such as Ag are connected via a wire, and are connected to the second substrate 10 by wire bonding. The second light emitting element 30b emits light having a predetermined wavelength in accordance with the current flowing between the second element electrodes 33b and 34b with a predetermined luminance, and the light is transmitted through the second element substrate 31b or directly. Output to the outside. As is well known, the second element substrate 31b can be omitted. Further, the connection between the second element electrodes 33b, 34b of the second light emitting element 30b and the connection pad 23 may be performed by a conventionally known flip lip connection technique using solder or the like as the bonding material 15.

  In the present embodiment, an LED that emits UV light whose wavelength peak of light emitted from the second light emitting element 30b is, for example, 250 to 395 [nm] or less is employed. That is, in the present embodiment, a UV-LED element is employed as the second light emitting element 30b. The second light emitting element 30b is formed by a conventionally known thin film forming technique.

  In the present embodiment, the spectral peaks of the wavelengths of the light emitted by the first light emitting element 30a and the second light emitting element 30b are the same.

  According to the light irradiation device of the present embodiment, a plurality of first light emitting elements, a first substrate having a plurality of openings each having at least one of the plurality of first light emitting elements disposed on one main surface, and a plurality of first light emitting elements. And a second substrate on which the plurality of second light emitting elements are arranged on one main surface. The second substrate is made of a material that transmits light emitted from the first light emitting element, and is disposed to cover at least one of the plurality of openings with the other main surface, and the plurality of second light emitting elements Is disposed in a region other than the region corresponding to the opening. In addition, a heat radiating portion is provided between the first substrate and the second substrate or in the second substrate. Therefore, each heat generated by the plurality of first light emitting elements and the plurality of second light emitting elements is radiated well, and the amount of heat transmitted from each light emitting element to the second substrate and the first substrate is reduced. The first substrate and the second substrate are satisfactorily prevented from becoming excessively hot, and the heat dissipation of the first substrate is maintained high.

  Therefore, according to the light irradiation device 1 of the present embodiment, even if the mounting density of the ultraviolet light emitting elements is relatively high, it is hardly affected by the heat generated by the ultraviolet light emitting elements themselves and realizes a relatively high ultraviolet irradiation energy. A light irradiation device is realized.

(Embodiment of light irradiation module)
The light irradiation module 100 shown in FIGS. 3 and 4 includes a heat radiation member 110 and a plurality of light irradiation devices 1 arranged on the heat radiation member 110. Such a light irradiation module 100 is incorporated in a printing apparatus such as an offset printing apparatus or an inkjet printing apparatus that uses an ultraviolet curable ink, and irradiates ultraviolet rays after applying the ultraviolet curable ink to a recording medium, thereby irradiating ultraviolet rays. It functions as an ultraviolet irradiation device that cures the curable ink.

  The heat radiating member 110 functions as a support for the plurality of light irradiation devices 1. As a material for forming the heat radiating member 110, a material having a high thermal conductivity is preferable. Examples thereof include various metal materials, ceramics, and resin materials. The heat radiating member 110 of this embodiment is made of copper.

On the other hand, the light irradiation device 1 is bonded to the heat radiating member 110 via a second adhesive 72 such as a silicone resin or an epoxy resin and arranged in a row on the heat radiating member 110.

  In order to make the illuminance distribution in the column direction of the light irradiation module 100 uniform, it is preferable that the adjacent light irradiation devices 1 are in close contact with each other.

  Thus, the light irradiation module 100 in which the plurality of light irradiation devices 1 are arranged on the heat radiating member 110 can irradiate the recording medium with a relatively wide ultraviolet ray.

  Moreover, the light irradiation module 100 of this embodiment has the light irradiation device 1 arranged in a line on the heat radiating member 110, and can enjoy the above-described effects of the light irradiation device 1.

(Embodiment of printing apparatus)
As an embodiment of the printing apparatus of the present invention, the printing apparatus 200 shown in FIGS. 5 and 6 will be described as an example. The printing apparatus 200 includes a transport mechanism 210 for transporting the recording medium 250, an inkjet head 220 as a printing mechanism for printing on the transported recording medium 250, and an ultraviolet for the recording medium 250 after printing. The light irradiation module 100 which irradiates light and the control mechanism 230 which controls light emission of the light irradiation module 100 are provided. Here, the recording medium 250 corresponds to the above-described object.

  The transport mechanism 210 is for transporting the recording medium 250 so as to pass through the inkjet head 220 and the light irradiation module 100 in this order, and a pair of transports that are disposed opposite to the mounting table 211 and are rotatably supported. And a roller 212. The recording medium 250 supported by the mounting table 211 is sent between the pair of transport rollers 212, and the transport roller 212 is rotated to send the recording medium 250 in the transport direction.

  The inkjet head 220 has a function of attaching a photosensitive material to the recording medium 250 conveyed via the conveyance mechanism 210. The ink-jet head 220 is configured to eject droplets containing the photosensitive material toward the recording medium 250 and adhere to the recording medium 250. In the present embodiment, ultraviolet curable ink is employed as the photosensitive material. Examples of the photosensitive material include a photosensitive resist and a photocurable resin in addition to the ultraviolet curable ink.

  In the present embodiment, a line-type inkjet head is adopted as the inkjet head 220. The inkjet head 220 has a plurality of ejection holes 220a arranged in a line, and is configured to eject ultraviolet curable ink from the ejection holes 220a. The inkjet head 220 ejects ink from the ejection holes 220a to the recording medium 250 transported in a direction orthogonal to the arrangement of the ejection holes 220a, and deposits the ink on the recording medium, whereby the recording medium 250 Printing is performed.

  In the present embodiment, a line-type inkjet head has been described as an example of the printing mechanism, but the present invention is not limited to this. For example, a serial-type inkjet head may be employed, A serial type spray head may be employed. Further, as the printing mechanism, an electrostatic head that accumulates static electricity of the recording medium 250 and attaches the photosensitive material with the static electricity may be employed, or the recording medium 250 is immersed in a liquid photosensitive material and the photosensitive medium is used. An immersion apparatus for attaching a conductive material may be employed. Further, a brush, a brush, and a roller may be employed as the printing mechanism.

In the printing apparatus 200, the light irradiation module 100 has a function of exposing the photosensitive material attached to the recording medium 250 conveyed via the conveyance mechanism 210. The light irradiation module 100 is provided on the downstream side in the transport direction with respect to the inkjet head 220. In the printing apparatus 200, the first light emitting element 30 a and the second light emitting element 30 b have a function of exposing the photosensitive material attached to the recording medium 250.

  The control mechanism 230 has a function of controlling the light emission of the light irradiation module 100. The memory of the control mechanism 230 stores information indicating light characteristics that make it relatively good to cure the ink droplets ejected from the inkjet head 220. Specific examples of the stored information include wavelength distribution characteristics suitable for curing ejected ink droplets, and numerical values representing emission intensity (emission intensity in each wavelength range). In the printing apparatus 200 of the present embodiment, by including the control mechanism 230, the magnitude of the drive current input to the plurality of first light emitting elements 30a can be adjusted based on the stored information of the control mechanism 230. From this, according to the printing apparatus 200, light can be irradiated with an appropriate ultraviolet irradiation energy according to the characteristics of the ink to be used, and the ink droplet can be cured with a relatively low energy light.

  In the printing apparatus 200, the transport mechanism 210 transports the recording medium 250 in the transport direction. The inkjet head 220 discharges ultraviolet curable ink to the recording medium 250 being conveyed, and causes the ultraviolet curable ink to adhere to the surface of the recording medium 250. At this time, the ultraviolet curable ink to be attached to the recording medium 250 may be attached to the entire surface, partially attached, or attached in a desired pattern. In the printing apparatus 200, the ultraviolet curable ink adhered to the recording medium 250 is irradiated with ultraviolet rays emitted from the light irradiation module 100 to cure the ultraviolet curable ink.

  In the printing apparatus 200 of the present embodiment, the light irradiation devices 1 included in the light irradiation module 100 are arranged in a line on the heat radiation member 110, and the above-described effects of the light irradiation module 100 can be enjoyed.

  While specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, as in the first modification shown in FIG. 7, the flow path 80 formed in the second substrate 20 is formed in a region corresponding to the plurality of first light emitting elements 30 a arranged on the first substrate 10. It may not be done. With this configuration, the light emitted from the first light emitting element 30a is emitted only through the first adhesive 71 and the second substrate 20 without passing through the refrigerant, and thus the light extraction efficiency. Can be kept high. Note that the shape of the flow path is not particularly limited regardless of whether the flow path is formed on the first light emitting element 30a. What is necessary is just to design suitably so that the in-plane temperature variation of the light irradiation device 1 may become small in the state which the light irradiation device 1 drives.

  Further, in the present embodiment, the flow path 80 is provided inside the second substrate 20, but a recess is provided on the other main surface 21b of the second substrate 20 as in the second modification shown in FIG. A flow path may be formed between the first substrate 10 and the second substrate 20 by bonding the first substrate 10 and the second substrate. FIG. 9 shows a plan view and a sectional view of the second substrate 20. With such a structure, the processing of the second substrate 20 becomes easy.

Further, as in the third modification shown in FIGS. 10 and 11, a recess is provided on each of the contact surfaces of the first substrate 10 and the second substrate 20, and a flow path is provided between the first substrate and the second substrate. It may be formed. With such a structure, the flow path 80 is in direct contact with not only the second substrate 20 but also the first substrate 10, so that the heat of the first substrate 10 and the heat of the second substrate 20 are effectively radiated. be able to.

  Further, as in the fourth modification shown in FIGS. 12 and 13, the region other than the region corresponding to the opening 12 of the first substrate 10 on the one main surface 21 a of the second substrate 20, the second electrical wiring It is preferable to have a heat dissipation plate 90 made of a metal layer such as copper (Cu), aluminum (Al), or gold (Au) in a region excluding 62 and the electrode pad 23. The heat radiating plate 90 also functions as a heat radiating portion, like the channel 80. The heat generated by the plurality of second light emitting elements 30b is concentrated on the region of the second substrate 20 located immediately below the second light emitting element 30b. Therefore, a heat sink 90 made of a metal layer is provided, and heat generated by the plurality of second light emitting elements 30b is transferred to the heat sink 90, so that a region of the second substrate 20 located directly below the second light emitting element 30b is formed. Concentration of heat can be relatively suppressed.

  In the fourth modification, the heat radiating plate 90 made of a metal layer is formed on the one main surface 21a of the second substrate 20, but even if it is formed on the other main surface 21b of the second substrate 20, the one main surface 21a and the other main surface 21a. You may form in both the main surfaces 21b. When forming on the other main surface 21 b, the heat radiating plate 90 can be formed in a region other than the region corresponding to the opening 12 of the first substrate 10.

  In the fourth modification, the second substrate 20 having the flow path 80 and the heat radiating plate 90 at the same time is used as the heat radiating portion, but only the heat radiating plate 90 may be provided as the heat radiating portion. When both the flow path 80 and the heat radiating plate 90 are provided as the heat radiating portion, it is preferable because the heat generated by the plurality of second light emitting elements 30b can be radiated more effectively. Two substrates are preferable from the viewpoint of productivity and cost because they are easy to manufacture.

  Although not shown, the first light emitting element 30a and the second light emitting element 30b of the light irradiation device of the present embodiment are the same light emitting element having the same light wavelength spectrum, but different light wavelengths. The first light emitting element 30a and the second light emitting element 30b having the peak of the spectrum may be used. By arranging light emitting elements having a plurality of light wavelength spectrum peaks in one light irradiation device in this way, curing performance such as shortening the curing time of ultraviolet curable ink can be improved, or in the sensitive wavelength region. There is an advantage that different ultraviolet curable inks can be cured by the same light irradiation device.

  In this case, it is preferable to shorten the wavelength of light emitted from the light emitting element disposed on the substrate having higher thermal conductivity. This is because the currently provided ultraviolet light emitting elements generate a relatively large amount of heat as the wavelength of light emitted by the light emitting elements is shorter. That is, by increasing the thermal conductivity of the substrate on which the light emitting element that generates a large amount of heat is mounted, it is possible to dissipate the heat generated by the light emitting element satisfactorily.

  Furthermore, in the present embodiment, the second substrate 20 is bonded to the first substrate 10 via the first adhesive 71, but the first substrate 10 is separately provided between the first substrate 10 and the second substrate 20. In addition, a heat insulating material having a thermal conductivity lower than that of the second substrate 20 may be disposed (not shown). As a heat insulating material, it can form with fiber type heat insulating materials, such as glass wool and rock wool, and foam type heat insulating materials, such as a urethane foam, a phenol foam, a polystyrene foam, etc., for example. However, in the case of a heat insulating material that does not have optical transparency, an opening is similarly provided in the region of the heat insulating material corresponding to the opening 12 of the first substrate. In the case where a light-transmitting material such as an epoxy resin or a silicone resin is used as the heat insulating material, the heat-transmitting material may be disposed so as to cover the opening 12 of the first substrate. You may provide an opening part in the area | region corresponding to the opening part 12 of a 1st board | substrate like the case of the heat insulating material which does not have.

Further, as in the fifth modification shown in FIGS. 14 and 15, the optical lens 17a and the optical lens 17b may be disposed so as to cover the first light emitting element 30a and the second light emitting element 30b. The optical lenses 17a and 17b have a function of condensing light emitted from the first light emitting element 30a and the second light emitting element 30b, respectively. The optical lens 17a is disposed on the one main surface 21a of the second substrate 20 via a third adhesive 73 such as an epoxy resin or a silicone resin so as to correspond to the opening 12 of the first substrate 10. . The optical lens 17a is formed of, for example, silicone. In addition to the silicone described above, examples of the material of the optical lens include thermosetting resins such as urethane and epoxy, plastics such as thermoplastic resins such as polycarbonate and acrylic, sapphire, and inorganic glass. The optical lens 17b is formed integrally with the second substrate 20 by a conventionally known injection molding method or the like, for example, with silicone or the like so as to cover the second light emitting element. In the optical lenses 17a and 17b of the second modified example, one main surface is convex and the other main surface is flat, and the cross-sectional area decreases from the other main surface toward the one main surface. A plano-convex lens is used. The optical lens 17 is not limited to the plano-convex lens described above, and a Fresnel lens or the like may be used.

  The embodiment of the printing apparatus 200 is not limited to the above embodiment. For example, a so-called offset printing type printer that rotates a shaft-supported roller and conveys a recording medium along the roller surface may exhibit the same effect.

  In the present embodiment, an example in which the light irradiation module 100 is applied to the printing apparatus 200 using the inkjet head 220 is shown, but the light irradiation module 100 cures, for example, a photo-curing resin spin-coated on the surface of the object. It can also be applied to the curing of various types of photo-curing resins such as dedicated devices. Moreover, you may use the light irradiation module 100 for the irradiation light source etc. in an exposure apparatus, for example.

DESCRIPTION OF SYMBOLS 1 Light irradiation module 10 1st board | substrate 11a One main surface 12 Opening part 13 Connection pad 14 Inner peripheral surface 15 Joining material 17 Optical lens 20 2nd board | substrate 21a One main surface 21b The other main surface 23 Connection pad 30a 1st light emitting element 30b 1st Two light emitting elements 31a First element substrate 31b Second element substrate 32a First semiconductor layer 32b Second semiconductor layers 33a and 34a First element electrodes 33b and 34b Second element substrate 40 Sealant 50 Laminate 51 First insulating layer 52 2nd insulating layer 61 1st electrical wiring 62 2nd electrical wiring 71 1st adhesive agent 72 2nd adhesive agent 73 3rd adhesive agent 80 Flow path 90 Heat sink 100 Light irradiation module 110 Heat radiation member 200 Printing Device 210 Conveying Mechanism 211 Loading Table 212 Conveying Roller 220 Inkjet Head 220a Discharge Hole 230 Control Mechanism 250 Recording Medium 300 Heat material

Claims (8)

A plurality of first light emitting elements;
On the other hand, a first substrate having a plurality of openings each having at least one of the plurality of first light emitting elements disposed on the main surface;
A plurality of second light emitting elements;
And a second substrate on which the plurality of second light emitting elements are arranged on the main surface,
The second substrate is made of a material that transmits light emitted from the first light emitting element, and is disposed so as to cover at least one of the plurality of openings with the other main surface,
The plurality of second light emitting elements are arranged in a region other than a region corresponding to the opening,
A light irradiating device comprising a heat radiating portion between the first substrate and the second substrate or in the second substrate.   2. The light irradiation device according to claim 1, wherein the heat radiating portion includes a flow path through which a coolant can flow inside the second substrate.   2. The light irradiation device according to claim 1, wherein the heat radiation portion includes a flow path through which a coolant can flow between the first substrate and the second substrate.   The heat dissipation part includes a metal layer formed in a region other than a region corresponding to the opening in at least one of the one main surface and the other main surface of the second substrate. 4. The light irradiation device according to any one of 3 above.   5. The light irradiation device according to claim 1, wherein a wavelength of light emitted from the first light emitting element is different from a wavelength of light emitted from the second light emitting element. The thermal conductivity of the first substrate is different from the thermal conductivity of the second substrate,
6. The wavelength of light emitted from a light emitting element disposed on a substrate having higher thermal conductivity is shorter than the wavelength of light emitted from a light emitting element disposed on the other substrate. The light irradiation device according to any one of the above.   A light irradiation module, wherein a plurality of light irradiation devices according to claim 1 are placed on a heat dissipation member. Printing means for printing on a recording medium;
A printing apparatus comprising: the light irradiation module according to claim 7, which irradiates light onto the printed recording medium.

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