JP2010149381A - Light irradiation head, liquid droplet curing device, and liquid droplet curing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To irradiate an object with a light of relatively high luminous energy, at a relatively small luminous energy distribution. <P>SOLUTION: This light irradiation head includes a base body including a groove part extended along one direction on one main face, and a light emitting body arranged on bottom face of the groove part, an inner face of the groove part has an sloped face getting near to the center of the groove part along with approach to a bottom face side, and the light emitting body has a plurality of light emitting areas arrayed along the one direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light irradiation head, a droplet curing device, and a droplet curing method.

  Ultraviolet curable resins and paints are widely used from the field of resist film formation and printing to the field of bonding and fixing small parts in an assembly process such as an optical pickup. In recent years, a printing method using ultraviolet curable ink (UV ink) has been attracting attention for reasons such as diversification of printing media, consideration for the environment, and increase in printing speed. In printing using UV ink, the UV ink is attached to a printing medium, and the attached ink is irradiated with ultraviolet light (UV light) to cure the UV ink in a short time.

Conventionally, fluorescent lamps such as a high-pressure mercury lamp and a low-pressure mercury lamp have been used as a light source of an ultraviolet irradiation head for curing such an ultraviolet curable resin. In recent years, for example, a printing apparatus using a UVLED array in which a plurality of UVLED elements emitting UV light are arranged as an irradiation light source has been proposed, such as an ink jet recording apparatus described in Patent Document 1 below. FIG. 7 is an example of a UVLED array described in Patent Document 1 below. In the conventional UVLED array, a plurality of concave reflecting structures 119 are arranged on the main surface of the substrate 118, and a light emitting element 119 such as an LED element is arranged in each reflecting mirror structure.
JP 2005-104108 A

  In such a conventional UVLED array, light from each light emitting element is formed by each reflecting mirror structure, and there is a problem that the unevenness of the amount of light irradiated from the UVLED array is relatively large. The present invention has been made for the purpose of solving such problems.

  In order to solve the above-mentioned problems, the present invention comprises a substrate having a groove portion extending in one direction on one main surface, and a light emitter disposed on the bottom surface of the groove portion, and the inner surface of the groove portion is There is provided a light irradiation head characterized by having a slope region that approaches the center of the groove as it approaches the bottom surface, and the light emitter has a plurality of light emitting regions arranged along the one direction.

  In addition, the light irradiation head, a moving mechanism for moving the light irradiation head relative to the target body opposed to the one main surface of the base, and the target body receiving light from the light irradiation head. There is also provided a droplet curing apparatus, comprising: a discharge unit that discharges a droplet of a photocurable material to be cured and attaches the droplet to the surface of the object.

  In addition, a photocurable material that is cured by receiving light emitted from the light irradiation head is attached to the surface of the object, and the liquid droplets attached to the surface of the object are irradiated to cure the liquid droplets. A droplet curing method is provided.

  According to the light irradiation head of the present invention, it is possible to irradiate an object with a relatively high light amount with a relatively small light amount distribution. According to the droplet curing apparatus and method of the present invention, it is possible to cure a droplet attached to an object in a relatively short time, and relatively little uneven curing on the surface of the object.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are illustrative, and the present invention is not limited to these embodiments.

  FIG. 1 is a diagram for explaining an irradiation head 10 that is an embodiment of the light irradiation head of the present invention, where (a) is a schematic perspective view of the irradiation head 10, and (b) is a schematic cross-sectional view of the irradiation head 10. is there. In the irradiation head 10, a plurality of long reflecting grooves 12 extending in one direction are arranged in parallel on one main surface of an insulating substrate 11 made of ceramic such as alumina. A light emitter 14 is disposed on the bottom surface of the reflection groove 12. In addition, on the bottom surface of the reflection groove 12, electrodes 24 a and 24 b for supplying electric power to the light emitters 14 and flip chip connecting the light emitters 14 are provided. Each electrode 24a, 24b is electrically connected to an input terminal provided outside via a wiring conductor 13 disposed inside the insulating substrate 11. In addition, the reflective groove 12 is filled with a sealing material 19 made of, for example, a silicone resin so as to cover the entire light emitter 14.

  The insulating substrate 11 has a configuration in which a reflecting portion 11B is disposed on the surface of a plate-like support portion 11A. The support portion 11A is made of, for example, an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, ceramics such as glass ceramics, or a resin such as an epoxy resin or a liquid crystal polymer (LCP). .

  When the support portion 11A is made of ceramics or the like, tungsten (W), molybdenum (Mo), manganese (Mn), in order to electrically connect the inside and outside of the light emitting device to a plurality of green sheets serving as the support portion 11A, By arranging the wiring conductor 13 made of a metal paste such as copper (Cu) and firing the support portion 11A, the metal paste is also fired at the same time, whereby the support portion 11A having the wiring conductor 13 is formed. Such a wiring conductor 13 may be formed using the known metallization method or plating method. When the support portion 11A is an insulator made of resin, the wiring conductor 13 is made of a metal material such as Cu, Ag, Al, iron (Fe) -nickel (Ni) -cobalt (Co) alloy, or Fe-Ni alloy. The lead terminal is embedded in the base body 1, one end of the lead terminal is led out to the mounting portion 1 a, and the other end is led out to the side surface and the bottom surface of the base body 1 to be exposed.

  The insulating substrate 11 is configured by disposing a reflecting portion 11B on the upper surface of the supporting portion 11A. The reflecting portion 11B is a slope inclined such that the side surface facing the light emitter 14 faces upward in the figure. In the irradiation head 10, the light component emitted from the light emitter 14 toward the reflecting portion 11 </ b> B is reflected upward at the side surface of the reflecting portion 11 </ b> B (that is, the inner slope of the groove portion 12), and the efficiency is increased upward in the figure. Is irradiated. The reflecting portion 11B of the present embodiment is made of porous ceramics that are visually recognized as white under a white light source, and has relatively good reflectivity with respect to light in the ultraviolet region, for example. The reflecting portion 11B may be made of ceramics such as an aluminum oxide sintered body, a zirconium oxide sintered body, and an aluminum nitride sintered body. Moreover, the reflection part 11B may be comprised with resin, such as an epoxy resin and a liquid crystal polymer (LCP). Further, in order to achieve a desired reflectivity, for example, a metallic material formed on the side surface of the reflective portion 11B by metal plating or vapor deposition according to the material of the reflective portion 11B, the wavelength of light emitted from the light emitter 14, or the like. A reflective film may be provided.

  The light-emitting body 14 is configured by providing a known LED light-emitting layer 17 made of a compound semiconductor such as GaN on one main surface of a substrate 15 made of sapphire or the like, for example. The substrate 15 of the light emitter 14 has a long shape along the longitudinal direction of the reflection groove 12. In the first embodiment, a plurality of light emitting layers 17 are arranged on one main surface of the substrate 15 along the length direction of the substrate 15. In the present embodiment, these light emitting layers 17 are provided on the main surface of the substrate 15 on the side facing the bottom surface of the groove 12 of the insulating substrate 11 (the lower side in FIG. 1B). For example, after a compound semiconductor layer made of GaN or the like is formed on the entire main surface of the substrate made of sapphire, it is partially removed by a known etching technique, so that it is formed on one main surface of the substrate 15 as in this embodiment. The light emitting layer 17 can be provided in a state of being separated. In the present embodiment, the light emitting layer 17 is a light emitting region.

  By disposing the plurality of light emitting layers 17 on the one main surface of the substrate 15 extending in the longitudinal direction so as to be spaced apart from each other, the interval along the longitudinal direction of each light emitting layer 17 can be made relatively small. For example, as in the conventional irradiation head shown in FIG. 7, in the case where each light emitting element is arranged in the reflecting structure, the geometric restrictions in manufacturing this reflecting structure, and the minute light emitting elements are Due to restrictions in holding and mounting, it is difficult to set the interval between the light emitting elements to, for example, 3.0 mm or less. On the other hand, when a plurality of separated light emitting layers 17 are formed on one main surface of the substrate 15 using, for example, a well-known semiconductor manufacturing technique, the interval along the longitudinal direction of each light emitting layer 17 is, for example, 1.0 mm. It is also possible to make it less than 0.5 mm, and even less than 0.5 mm.

  The light emitting layer 17 of the present embodiment is a so-called UVLED element having a light emission wavelength and a peak spectrum of 380 nm or less, for example. The light emitting layer 17 is formed by laminating a plurality of semiconductor crystal layers on one main surface of the substrate 15 (each semiconductor layer is not shown). More specifically, the light emitting layer 17 is formed from, for example, one of the substrate 15, one of the n-type and p-type conductive semiconductor layers, the contact layer, and one of the n-type and p-type. The other conductive type semiconductor layer and the contact layer are formed by being stacked in the order described.

  Further, on the surface of the light emitting layer 17 (the surface on the side facing the bottom surface of the groove 12), for example, an electrode 25a mainly composed of Ag and an electrode 25b are provided. The electrodes 25 a and 25 b provided on the surface of each light emitting layer 17 are flip-chip connected to the electrodes 24 a and 24 b provided on the bottom surface of the groove 12, so that each light emitter 14 is placed in the groove 12. The placement is fixed. The light emitting layer 17 emits light of a light amount corresponding to the magnitude of the voltage value when a voltage is applied to each electrode 25a and electrode 25b. The substrate 15 of the present embodiment is made of sapphire and has relatively good transparency with respect to light emission from the light emitting layer 17.

  In the embodiment shown in FIG. 1, each of the plurality of light emitting layers 17 includes an electrode 25a and an electrode 25b. In this embodiment, the voltage applied to each light emitting layer 17 can be controlled independently for each light emitting layer 17. The configuration of the electrodes is not particularly limited. For example, a configuration in which long electrodes that are simultaneously connected to the plurality of light emitting layers 17 are arranged in the groove portion 12 and the same voltage is applied to the plurality of light emitting layers 17 at once. It is good. Further, the light emitting layers 17 may be electrically connected in parallel, or may be electrically connected in series.

  The sealing member 19 is made of, for example, a silicone resin, and transmits light emitted from the LED light emitting layer 17 satisfactorily. The refractive index of the sealing material 19 is, for example, about 1.4, which is closer to the refractive index of the substrate 15 (for example, the refractive index of sapphire 1.7) compared to the refractive index of air (about 1.0). It has become.

  FIG. 2 is a diagram illustrating the light irradiation state in the irradiation head 10 of the present embodiment. 2A shows the AA cross section shown in FIG. 1, and FIG. 2B shows the BB cross section shown in FIG. In the light irradiation head 1, a current is supplied to each of the plurality of light emitting layers 17 provided on the surface of the substrate 15 through the wiring conductor 13, the electrode 24 a, and the electrode 24 b, and each light emitting layer 17 emits light. 2A and 2B show a case where a plurality of light emitting layers 17 emit light simultaneously.

  In the irradiation head 10, the interval along the longitudinal direction of each light emitting layer 17 is relatively small, for example, less than 1.0 mm, and the light amount distribution along the longitudinal direction of light emitted from the plurality of light emitting layers 17 is as follows. It is relatively small. For example, light emitted from each light emitting layer 17 made of LED elements does not have particularly strong directivity, and is spread and irradiated in all directions spatially. In the irradiation head 10, the light emitted from the light emitting layer 17 is reflected by the reflective electrode 25 provided on the surface of the light emitting layer 17, the bottom surface of the groove 12, and the inner side surface of the groove 12, and is directed upward in the drawing. And efficiently irradiated. At this time, as shown in FIG. 2A, the light emitted from each light emitting layer 17 is reflected, for example, at the interface between the substrate 15 and the sealing material 19 and extends in the longitudinal direction of the groove 12. The interior propagates relatively well along this longitudinal direction. That is, the light emitted from the plurality of light emitting layers 17 is irradiated upward from the inside of the groove 12 while spreading to some extent along the longitudinal direction of the groove 12. Note that the sealing material 19 of the present embodiment has a refractive index relatively close to that of the substrate 15, and the light from the light emitting layer 17 is totally reflected at the interface of the substrate 15 made of sapphire, and the inside of the substrate 15. To prevent being trapped more than necessary. In addition, by changing the refractive index of the sealing material 19, the refractive index difference at the interface of the substrate 15 is changed, the total reflection angle at the interface of the substrate 15 is adjusted, and as a result, the light irradiated from inside the groove portion 12 is changed. The light amount and the light amount distribution can also be adjusted. In addition, this invention is not limited to having a sealing material.

  According to the irradiation head 10 of the present embodiment, the light emitted from each light emitting layer 17 is irradiated upward from within the groove 12 while spreading in the longitudinal direction of the groove 12. For this reason, the distribution of the amount of emitted light along the longitudinal direction of the groove 12 of the light upward from the groove 12 is relatively suppressed. Further, the light emission from each light emitting layer 17 is suppressed from spreading in a direction substantially perpendicular to the longitudinal direction of the groove 12, and is efficiently condensed and irradiated toward the upper side in the drawing. According to the irradiation head 10 of this embodiment, it is possible to irradiate light having a relatively high light amount while making the light amount distribution of the light along the longitudinal direction of the groove portion 12 relatively small.

  FIG. 3 is a schematic perspective view for explaining a second embodiment of the irradiation head of the present invention. FIG. 4 is a diagram for explaining a light irradiation state in the irradiation head 20 of the second embodiment. 4A shows an AA cross section shown in FIG. 3, and FIG. 4B shows a BB cross section shown in FIG. The irradiation head 20 of the second embodiment is a so-called face-up type mounting head in which the light emitting layer 17 provided on the substrate 15 is mounted facing upward in the drawing. Also in the irradiation head 20 of the second embodiment, light from each light emitting layer 17 propagates through the substrate 15 that is long along the longitudinal direction of the groove portion 12 and is irradiated upward from the inside of the groove portion 12 in the drawing. Is done. According to the irradiation head 10 of this embodiment, it is possible to irradiate light having a relatively high light amount while making the light amount distribution of the light along the longitudinal direction of the groove portion 12 relatively small.

  FIG. 5 is a schematic perspective view illustrating an irradiation head 30 according to the third embodiment of the present invention. In the irradiation head 30 of the third embodiment shown in FIG. 5, the light emitting layer 17 is continuously formed over almost the entire surface of the one main surface of the substrate 15. That is, in the irradiation head 30 according to the third embodiment, the light emitting layer 17 continuously extends along the longitudinal direction of the groove 12. In the irradiation head of the present invention, the substrate on which the light emitting element is provided has a long shape extending along the longitudinal direction of the groove part extending in one direction, and the light emitting element itself is arranged along the longitudinal direction of the groove part. It can be formed continuously. Even with such an irradiation head 30, it is possible to irradiate light having a relatively high light amount while making the light amount distribution of the light along the longitudinal direction of the groove portion 12 relatively small. In the irradiation head 30 shown in FIG. 5, the light emitter 14 may be disposed in the groove portion 12 with the light emitting layer 17 facing upward in the drawing. Similarly in this case, it is possible to irradiate light having a relatively high light amount while making the light amount distribution of the light along the longitudinal direction of the groove portion 12 relatively small.

  FIGS. 6A and 6B are diagrams for explaining an ink jet printer 50 that is an example of a droplet curing apparatus of the present invention that includes the irradiation head 10, and FIG. 2 is a schematic top view of the inkjet printer 50. FIG. FIG. 5B is a schematic sectional view of the ink jet printer 50.

  The ink jet printer 50 ejects ink droplets from the ink jet head 70 onto the surface of the recording medium 52 such as paper, which is transported in one direction (X direction in the drawing), and is attached to the surface of the recording medium 52. The ink droplets attached to the recording medium 52 are cured by irradiating the droplets with light having a predetermined wavelength distribution. The ink jet printer 50 includes a platen 54 on which the recording medium 52 is placed, a transport unit 60 having a feed roller 62 and a presser roller 64, and a movement for moving the ink jet head 70 relative to the platen 54. A mechanism 80 and the irradiation head 10 are included.

  The ink jet head 70 ejects photocurable ink droplets onto the surface of the recording medium 52 that is placed on the platen 54 and conveyed in accordance with an image signal input from the outside. The inkjet head 70 is a known inkjet head such as a so-called thermal type or bubble type. The inkjet head 70 is reciprocated along the Y direction in the drawing along the guide rail 82 provided in the moving mechanism 80.

  The recording medium 52 is conveyed by the conveying means 60, for example, along the X direction in the figure. As the recording medium 52 moves, the inkjet head 70 is also moved along the Y direction in the drawing. As the recording medium 52 and the inkjet head 70 move, an image signal is sent to the inkjet head 70 from a control unit (not shown). In the ink jet head 70, photocurable ink droplets are ejected toward the recording medium according to the image signal, and an image pattern (ink droplet pattern) corresponding to the image signal is formed on the surface of the recording medium 52.

  The irradiation head 10 is arranged so that the longitudinal direction of the groove 12 is substantially perpendicular to the recording medium conveyance direction (X direction in the figure). In the groove part 12, a plurality of light emitters 14 are arranged in series along the longitudinal direction, and a plurality of light emitting layers 17 are arranged along the longitudinal direction. The irradiation head 10 is disposed downstream of the recording medium 52 with respect to the inkjet head 70. In other words, the ink jet printer 50 is configured such that light from the irradiation head 10 is irradiated onto ink droplets ejected from the ink jet head 70 and attached to the surface of the recording medium 52. As described above, according to the irradiation head 10, it is possible to irradiate light having a relatively high light amount while making the light amount distribution of the light along the longitudinal direction of the groove portion 12 relatively small. That is, it is possible to irradiate the surface of the recording medium 52 ejected from the inkjet head 70 with a relatively high amount of light relatively uniformly along the longitudinal direction of the groove 12.

  According to the ink jet printer 70 of the present embodiment, ink droplets attached to the surface of the recording medium 52 can be cured in a relatively short time, and ink curing unevenness on the surface of the recording medium 52 is relatively small. For example, in a specific location along the Y direction in the figure, ink spreading or spreading is greater than the surroundings at this specific location, such as when the ink is locally hardened. In this case, in the image recorded on the recording medium, linear image unevenness along the recording medium conveyance direction (X direction) appearing at a position corresponding to the specific portion may be visually recognized. In the inkjet printer 70 of this embodiment, the occurrence of such image unevenness is also suppressed.

  In the ink head printer 70 of the present embodiment, the memory (not shown) of the control unit 10 of the irradiation head 10 has data indicating light characteristics that are relatively good for curing the ink droplets ejected from the inkjet head 70. Specifically, data representing wavelength distribution characteristics and emission intensity (emission intensity in each wavelength region) suitable for curing the ejected ink droplet is input. In the irradiation head 10, the control unit 30 can also adjust the magnitude of the drive current input to the plurality of light emitting layers 17 based on the input data input in advance. According to the ink head printer head 70, it is possible to irradiate light with an appropriate amount of light according to the characteristics of the ink used, and it is possible to cure ink droplets with relatively low energy light.

  The form of the ink jet printer 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 an irradiation head is applied to an ink jet printer using an ink jet head is shown. The irradiation head of the present invention can be applied to the curing of various types of photo-curing resins such as a dedicated device for curing a photo-curing resin spin-coated on the surface of an object. Further, for example, it may be used as an irradiation light source in an exposure apparatus. This case is also preferable in that a relatively high light amount can be irradiated with a relatively small light amount distribution. Moreover, like the irradiation head 10 of the above-mentioned 1st Embodiment, light emission from a some light emitting element can also be independently controlled, for example, selectively irradiates the light to the surface of the photosensitive material, It can also be used for an image forming apparatus that forms an image corresponding to the irradiated light.

  The irradiation head, the surface emitting irradiation head, the droplet curing device, and the droplet effect method of the present invention have been described above, but the present invention is not limited to the above-described embodiment and does not depart from the gist of the present invention. Of course, various improvements and modifications may be made within the scope.

It is a figure explaining the irradiation head 10 which is one Embodiment of the light irradiation head of this invention, (a) is a schematic perspective view of the irradiation head 10, (b) is a schematic sectional drawing of the irradiation head 10. FIG. It is a figure explaining the irradiation state of the light in the irradiation head 10 of this embodiment, (a) is the AA 'cross section shown in FIG. 1, (b) has shown the BB' cross section shown in FIG. . It is a schematic perspective view explaining 2nd Embodiment of the irradiation head of this invention. It is a figure explaining the irradiation state of the light in the irradiation head 20 of 2nd Embodiment shown in FIG. 3, (a) is an AA 'cross section shown in FIG. 3, (b) is BB shown in FIG. 'A cross section is shown. It is a schematic perspective view explaining the irradiation head 30 of the 3rd Embodiment of this invention. (A) And (b) is the schematic of one Embodiment of the inkjet printer which is an example of the droplet hardening apparatus of this invention comprised with the irradiation head 10, (a) is an inkjet printer 50 is a schematic top view of the ink jet printer 50, and FIG. It is a schematic perspective view shown about an example of the conventional irradiation head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Irradiation head 11 Insulating substrate 50 Inkjet printer 52 Recording medium 54 Platen 60 Conveying means 62 Feed roller 64 Pressing roller 70 Inkjet head 80 Moving mechanism 82 Guide rail

Claims (8)

A base having a groove extending in one direction on one main surface;
A light emitter disposed on the bottom surface of the groove,
The inner surface of the groove has a slope region that approaches the center of the groove as it approaches the bottom surface,
The light emitting head, wherein the light emitter has a plurality of light emitting regions arranged along the one direction. The light emitter has a substrate and a light emitting layer provided on one main surface of the substrate,
The light irradiation head according to claim 1, wherein the substrate is transparent to light emitted from the light emitting layer.   The light emitting head according to claim 1, wherein the light emitting region of the light emitter is provided on a main surface of the substrate on a side facing the bottom surface of the groove.   4. The light irradiation head according to claim 1, wherein the light emitter and the bottom surface of the groove are joined via a conductive layer that reflects light emitted from the light emitting region.   5. The light irradiation head according to claim 1, wherein the base is made of ceramics, and ceramics are exposed in at least a part of the inclined region of the groove.   The light emitting head according to claim 1, wherein the light emitting layer emits UV light. The light irradiation head according to any one of claims 1 to 6,
A moving mechanism for relatively moving the object opposed to the one main surface of the base body and the light irradiation head;
Discharging means for discharging droplets of a photocurable material that is cured by receiving light emitted from the light irradiation head to the object, and attaching the droplets to the surface of the object;
A droplet curing apparatus comprising: A photocurable material that is cured by receiving light emitted from the light irradiation head according to any one of claims 1 to 6 is attached to the surface of the object,
A droplet curing method comprising irradiating a droplet attached to a surface of the object to cure the droplet.

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