Laser induced thermal imaging apparatus, laser induced thermal imaging method using the apparatus, and method of fabricating organic light emitting display using the apparatus

A laser induced thermal imaging apparatus, and a laser induced thermal imaging method and a method of fabricating an organic light emitting display using the apparatus are provided. The laser induced thermal imaging apparatus includes a chuck for fixing an acceptor substrate. A lamination unit for laminating a donor film on the acceptor substrate is located on the chuck. The lamination unit includes a body having a cavity, a gas injection port for injecting a compression gas into the cavity and a gas discharge port for discharging the gas injected into the cavity onto the substrate. A laser irradiator for irradiating a laser beam on the laminated donor film through the lamination unit is located on the lamination unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 2004-108992, filed Dec. 20, 2004, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a laser induced thermal imaging apparatus and, more particularly, to a laser induced thermal imaging apparatus capable of simultaneously performing lamination and laser irradiation, and a laser induced thermal imaging method using the apparatus.

2. Description of the Related Art

In general, a laser induced thermal imaging (LITI) method requires at least a laser, an acceptor substrate, and a donor film. The donor film includes a base film, a light-heat conversion layer and a transfer layer. In an LITI process, the transfer layer is disposed opposite to the acceptor substrate to laminate the donor film on an entire surface of the acceptor substrate, and then to irradiate a laser beam on the base film. The beam irradiated on the base film is absorbed into the light-heat conversion layer to be converted into heat energy, and the transfer layer is transferred on the acceptor substrate by the heat energy. As a result, a transfer layer pattern is formed on the acceptor substrate. This is disclosed in U.S. Pat. Nos. 5,998,085, 6,214,520 and 6,114,088.

However, when the donor film is laminated on the entire surface of the acceptor substrate as described above, bubbles may locally remain between the acceptor substrate and the donor film. These bubbles may cause transfer failures.

In order to solve the problem, U.S. Pat. No. 6,226,020 discloses a method and apparatus for producing a print by means of laser induced thermal transfer. In accordance with '020 patent, a pattern is formed on the substrate by contacting a transfer tape having a width smaller than that of the substrate on the substrate provided on a substrate cylinder, and irradiating a laser beam on the transfer tape. At this time, contacting the transfer tape on the substrate is performed using a contact roll adjacent to the substrate. Additionally, a nozzle is disposed in a direction inclined to the laser beam, and a gas is ejected on the transfer tape using the nozzle to improve contact force between the transfer tape and the substrate.

Specifically, the contact roll functions to allow the transfer tape to surround the substrate cylinder with a predetermined wrap angle, and the wrap angle may form contact force and friction force between the transfer tape and the substrate on the substrate cylinder. However, when the transfer layer of the transfer tape is an organic layer, the friction force generated as described above is sufficient to damage the organic layer.

In addition, the nozzle is disposed in the direction inclined to the laser beam, since a distance between the nozzle and the substrate is too far, it may be difficult to obtain sufficient contact force between the transfer tape and the substrate using only the nozzle. In this case, in order to obtain the sufficient contact force, the nozzle should eject a plenty of high-pressure gas on the transfer tape. In particular, differently from '020 patent, when the substrate is not wound on the cylinder but located on a plane surface and the transfer tape and the substrate should be closely adhered to each other using only the gas pressure ejected from the nozzle without the contact roll, it may be more difficult to sufficiently obtain uniform contact force all over a predetermined region due to the far distance.

SUMMARY OF THE INVENTION

The present invention, therefore, solves aforementioned problems associated with conventional devices by providing a laser induced thermal imaging apparatus and a laser induced thermal imaging method using the apparatus capable of obtaining sufficient contact force between a donor film and an acceptor substrate without generating friction force between a transfer layer of the donor film and the acceptor substrate.

In an exemplary embodiment of the present invention, a laser induced thermal imaging apparatus is provided. The laser induced thermal imaging apparatus includes a chuck for fixing an acceptor substrate. A lamination unit for laminating a donor film on the acceptor substrate is located on the chuck. The lamination unit includes a body having a cavity, a gas injection port for injecting a compression gas into the cavity, and a gas discharge port for discharging the gas injected into the cavity onto the substrate. A laser irradiator for irradiating a laser beam on the laminated donor film through the lamination unit is located on the lamination unit. As a result, the laser beam may be irradiated on the donor film sufficiently laminated by means of the lamination unit. In addition, since the lamination unit performs a lamination process using gas ejection, it is possible to form a uniform gap between the body and the donor film, and the gap enables the lamination unit to move without direct friction when the lamination unit moves on the donor film.

The lamination unit may be installed at an upper portion of the body, and may include a light transmission window in contact with the cavity. In this case, the gas injection port may pass through a sidewall of the body. At this time, the laser beam may be irradiated on the donor film through the light transmission window, the cavity, and the gas discharge port.

The gas injection port may pass through an upper portion of the lamination unit body, and the gas discharge port may pass through a lower portion of the lamination unit body. At this time, the laser beam may be irradiated on the donor film through the gas injection port, the cavity, and the gas discharge port.

The lamination unit may further include an exhaust port for exhausting gas discharged in the chuck at an outer periphery of the body. The exhaust port may be connected to an exhaust pump.

The apparatus may further include a guide roll for contacting the donor film on the acceptor substrate to at least one side of the lamination unit. As a result, it is possible to more effectively laminate the donor film on the acceptor substrate.

Preferably, the laser irradiator and the lamination unit are simultaneously movable in a Y-direction crossing the chuck. On the other hand, in another embodiment of the present invention, the lamination unit may have a line shape extending the Y-direction crossing the chuck. In this case, the laser irradiator may irradiate a laser as moving in the Y-direction along the lamination unit.

The donor film may have a ribbon shape. The ribbon-shaped donor film may include protrusions at both edges thereof. In addition, the laser induced thermal imaging apparatus may further include film supply means at one side of the lamination unit, and film winding means at the other side of lamination unit. Further, preferably, the laser irradiator, the lamination unit, the film supply means and the film winding means are simultaneously movable in the Y-direction crossing the chuck.

The donor film may be located on an entire surface of the acceptor substrate. In this case, at least two corners of the donor film are preferably attached to a frame. Furthermore, the chuck may fix the frame.

In another exemplary embodiment of the present invention, a laser induced thermal imaging method is provided. The method includes locating an acceptor substrate on a chuck. A donor film including at least a light;heat conversion layer and a transfer layer is located to make the transfer layer opposite to the lower substrate. A portion of the donor film is locally laminated on the acceptor substrate using the lamination unit, and simultaneously, the laser is irradiated on the laminated donor film through the lamination unit to transfer at least a portion of the transfer layer on the acceptor substrate. As a result, the laser beam may be irradiated on the donor film sufficiently laminated by means of the lamination unit.

Further, the lamination unit may perform a lamination process using air pressure. As a result, since the lamination unit performs the lamination process using gas discharge, it is possible to make a uniform gap between the body and the donor film, and the gap enables to allow the lamination unit to move without direct friction when the lamination unit moves on the donor film.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, when it is described that a layer is existed “on” another layer or a substrate, the layer may be directly formed on another layer or a substrate, or a third layer may be interposed between them. Like reference numerals designate like elements throughout the specification.

FIG. 1is a schematic perspective view of a laser induced thermal imaging apparatus in accordance with an embodiment of the present invention, andFIG. 2is an enlarged perspective view of A-portion shown inFIG. 1.

Referring toFIGS. 1 and 2, a laser induced thermal imaging apparatus100includes a substrate stage110. A chuck115is located on the substrate stage110. The substrate stage110includes a chuck guide bar113for moving the chuck115in an X-direction. Therefore, the chuck115is movable along the chuck guide bar113in the X-direction. The chuck115fixes an acceptor substrate50to be located on the chuck115.

An optical stage120disposed in a direction crossing the chuck115is located on the chuck115. A laser irradiator130is installed on the optical stage120. The laser irradiator130may include a light source131, a beam shaping element132, a mask135, and a projection lens137. The light source131is an apparatus for generating a laser beam L. The laser beam L generated from the light source131passes through the beam shaping element132. The beam shaping element132may deform a beam having a Gaussian profile generated in the light source131to a beam L_i having a homogenized flat-top profile. The homogenized beam L_i may pass through the mask135. The mask135includes at least one light transmission pattern or at least one light reflection pattern. While only the light transmission patterns135aare shown in the drawings, it is not limited thereto. The beam passed through the mask135may have an image L_m patterned by the patterns135a. The beam having the patterned image L_m passes through the projection lens137.

The optical stage120includes a laser guide bar123for moving the laser irradiator130in a Y-direction. Further, the laser irradiator130is mounted on a top surface of the optical stage120, specifically on the laser guide bar123through a laser irradiator base125.

A lamination unit150is mounted on a side of the optical stage120. The lamination unit150is an element for locally laminating a donor film70on the acceptor substrate50. The laser irradiator130is located on the lamination unit150. The laser irradiator130irradiates a laser beam passed through the projection lens137on the lamination unit150. The lamination unit has a light transmission part in a passage through which the laser beam is passed. Therefore, the laser beam may be irradiated on the laminated donor film70through the lamination unit150, specifically, through the light transmission part of the lamination unit150. As a result, a laser induced thermal imaging process may be performed together with the lamination. In addition, since the lamination is locally performed, although bubbles are generated between the acceptor substrate50and the donor film70of the laminated part, the bubbles may escape through between the donor film70and the acceptor substrate50of the non-laminated part located at a periphery portion. Eventually, it is possible to prevent transfer failures due to the bubbles. Further, as the laser beam is irradiated through the lamination unit150, the laser beam may be irradiated on a portion where the lamination is sufficiently performed. As a result, it is possible to obtain an excellent transfer pattern profile.

The lamination unit150may be an apparatus for performing the lamination using air pressure. Specifically, the lamination unit150may include a body151having a cavity151a, a gas injection port151bfor injecting a compression gas Ca into the cavity151a, and a gas discharge port151cfor discharging the gas injected into the cavity151aonto the chuck. The donor film70may be laminated on the acceptor substrate50by the pressure of the compression gas Ca, and the gas discharged through the gas discharge port151cis exhausted to the exterior of the lamination unit150, thereby forming a predetermined gap between the body151and the donor film70.

The lamination unit150may include a light transmission window155installed at an upper portion of the body151, which may be in contact with the cavity151a. In this case, the laser irradiated from the laser irradiator130may be irradiated on the donor film70through the light transmission window155, the cavity151a, and the gas discharge port151c. Therefore, the light transmission window155, the cavity151aand the gas discharge port151cmay constitute a light transmission part. At this time, the gas injection port151bmay be installed to pass through a sidewall of the body151. The body151of the lamination unit150has a hexahedron shape as shown in figure, but it is not limited thereto, it may be a circular cylinder shape.

The donor film70may have a ribbon shape. Since the ribbon-shaped donor film70has a width smaller than that of the acceptor substrate50, it is easy to obtain uniformity in manufacturing the film in comparison with the case of manufacturing the donor film having a width similar to or larger than that of the substrate50. In this case, film supply means143may be installed at one side of the lamination unit150, and film winding means144may be installed at the other side of the lamination unit150. Preferably, the film supply means143and the film winding means144have roll shapes. The film supply means143and the film winding means144may apply a certain tension to the donor film70.

The lamination unit150and the laser irradiator130are simultaneously movable in a Y-direction being a moving direction of the laser irradiator130. As an example for implementing this, the lamination unit150is installed at a lamination unit base141, and the lamination unit base141may be connected to the laser irradiator base125. As a result, when the laser irradiator base125is moved in the Y-direction, the laser irradiator130installed on the laser irradiator base125and the lamination unit base141may be also moved in the Y-direction. Eventually, the lamination unit150installed at the lamination unit base141may be also moved in the Y-direction.

Further, preferably, the film supply means143and the film winding means144are simultaneously movable in the Y-direction together with the lamination unit150. As an example for implementing this, the film supply means143and the film winding means144may be individually installed at the lamination unit base141to be spaced apart form the lamination unit150. Therefore, the laser irradiator130, the lamination unit150, the film supply means143and the film winding means144are simultaneously movable in the Y-direction as a whole.

In addition, the lamination unit base141may include a lamination unit guide bar142for moving the lamination unit150up and down.

FIG. 3is a cross-sectional view of a donor film in accordance with an embodiment of the present invention, which is taken along the line III-III′ inFIG. 1.

Referring toFIG. 3, a donor film70includes a base film71, and a light-heat conversion layer73and a transfer layer77, which are sequentially deposited on a surface of the base film71. In addition, the donor film70is wound on the film winding means144(seeFIG. 1) and the film supply means143(seeFIG. 1) in a multi-layered manner. The base film71may be a substrate formed of a transparent polymer organic material such as polyethyleneterephthalate (PET) and so on. The light-heat conversion layer73, as a layer for converting incident light to heat, may include a light absorbing material such as aluminum oxide, aluminum sulfide, carbon black, graphite, and infrared dye. When a bottom substrate A is an organic light emitting display substrate, the transfer layer77may be an organic transfer layer. The organic transfer layer77may be one layer selected from a group consisting of a hole injection organic layer, a hole transport organic layer, an emissive organic layer, a hole blocking organic layer, an electron transport organic layer, and an electron injection organic layer.

Protrusions72may be located on a surface opposite to a surface, at which the transfer layer77of the base film71is deposited. As described above, the protrusions72may prevent the transfer layer from being damaged, when the donor film is deposited in a multi-layered manner. Further, preferably, the protrusions72are located at both edges of the base film71. In addition, preferably, a height of each of the protrusions72is larger than the sum of thicknesses of various layers deposited on the base film71, i.e., the light-heat conversion layer73and the transfer layer77.

FIG. 4is an enlarged cross-sectional view illustrating a partial region of an organic light emitting display substrate of an embodiment of the acceptor substrate inFIG. 1.

Referring toFIG. 4, a semiconductor layer52is located on a predetermined region of a substrate51. The semiconductor layer52may be an amorphous silicon layer or a polysilicon layer that the amorphous silicon layer is crystallized. A gate insulating layer53is located on the semiconductor layer52. A gate electrode54overlapping the semiconductor layer52is located on the gate insulating layer53. A first interlayer insulating layer55covering the semiconductor layer52and the gate electrode54is located on the gate electrode54. Source and drain electrodes56and57passing through the first interlayer insulating layer55and the gate insulating layer53to be in contact with both ends of the semiconductor layer52respectively are located on the first interlayer insulating layer55. The semiconductor layer52, the gate electrode54, and the source and drain electrodes56and57constitute a thin film transistor T. A second interlayer insulating layer58covering the source and drain electrodes56and57is located on the source and drain electrodes56and57. The second interlayer insulating layer58may include a passivation layer for protecting the thin film transistor T and/or a planarization layer for attenuating a step due to the thin film transistor. A pixel electrode59passing through the second interlayer insulating layer58to be in contact with the drain electrode57is located on the second interlayer insulating layer58. The pixel electrode59may be, for example, an ITO (indium tin oxide) layer or an IZO (indium zinc oxide) layer. A pixel defining layer60having an opening60afor exposing a portion of the pixel electrode may be located on the pixel electrode59.

Hereinafter, a laser induced thermal imaging method and method of fabricating an organic light emitting display using the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 and 2will be described.

FIG. 5is a cross-sectional view taken along the line I-I′ inFIG. 1, andFIG. 6is a cross-sectional view taken along the line II-II′ inFIG. 1.

Referring toFIGS. 1,5and6, an acceptor substrate50is located on a chuck115. The acceptor substrate50may be the organic light emitting display substrate described in conjunction withFIG. 4.

A donor film70is located on the acceptor substrate50. The donor film70includes at least a light-heat conversion layer73(seeFIG. 3) and a transfer layer77, and the transfer layer77is located opposite to the acceptor substrate50. The donor film70may have a ribbon shape.

Next, a lamination unit150moves downward along a lamination unit guide bar142. As a result, the donor film70under the lamination unit150may be also moved onto the acceptor substrate50. The lamination unit150may be an apparatus for performing lamination using air pressure. Specifically, the lamination unit150may include a body151having a cavity151a, a gas injection port151bfor injecting a compression gas Ca into the cavity151a, and a gas discharge port151cfor discharging the gas injected into the cavity151aonto the chuck. Further, the lamination unit150may include a light transmission window155installed at an upper portion of the body151, which may be in contact with the cavity151a. In addition, the gas injection port151bmay be installed to pass through a sidewall of the body151.

Next, the compression gas Ca is injected into the cavity151athrough the gas injection port151bof the lamination unit150. Herein, “compression gas” refers that its gas pressure is higher than atmospheric pressure of the exterior of lamination unit150. The compression gas injected into the cavity151ais discharged through the gas discharge port151c. At this time, a portion of the donor film70may be locally laminated on the acceptor substrate50by means of the pressure P of the compression gas, and the gas discharged through the gas discharge port151cmay be exhausted to the exterior of the lamination unit150, thereby forming a predetermined gap between the body151and the donor film70.

Simultaneously, a laser beam is emitted from a light source131(seeFIG. 2) of a laser irradiator130to transmit a projection lens137. The laser beam transmitted the projection lens137passes through the light transmission part of the lamination unit150, i.e., the light transmission window155, the cavity151aand the gas discharge port151cto be irradiated on the donor film70. At this time, the pressure applied to the donor film by the lamination unit150, i.e., the pressure P of the compression gas may be parallel to a direction that the laser beam is irradiated. Therefore, the laser beam is irradiated on a portion, at which the donor film70is sufficiently laminated on the acceptor substrate50, to enable to reduce transfer inferiority. As a result, it is possible to obtain an excellent transfer pattern profile.

The light-heat conversion layer73(seeFIG. 3) absorbs the laser beam to generate heat at a region of the donor film70, at which the laser beam is irradiated, and the transfer layer77under the light-heat conversion layer73is transferred on the acceptor substrate50due to variance of contact force with the light-heat conversion layer73caused by the heat. Finally, a patterned transfer layer77ais formed on the acceptor substrate50.

A laser irradiator base125continuously moves in a Y-axis direction along a laser guide bar123. Therefore, the laser irradiator130installed at the laser irradiator base125, a lamination unit base141connected to the laser irradiator base125, the lamination unit150installed at the lamination unit base141, donor film supply means143and donor film winding means144may be also continuously moved in the Y-axis direction. As a result, the lamination and the laser irradiation may be continuously performed in the Y-direction.

At this time, the donor film winding means144winds the donor film at a speed synchronized with a speed that the laser irradiator base125, i.e., the laser irradiator130moves. As a result, a portion having a non-patterned transfer layer77of the donor film70may be continuously located under the lamination unit150. At this time, the lamination unit150may be moved on the donor film70without friction by a direct contact with the donor film70due to a gap between the body151and the donor film70. As a result, when the transfer layer of the donor film70is an organic layer, it is possible to minimize damage of the organic layer.

When the laser irradiator130arrives at an edge of the acceptor substrate50, the compression gas is not supplied to the lamination unit150, and the lamination unit150moves upward along the lamination unit guide bar142. As a result, the donor film70under the lamination unit150is detached from the acceptor substrate.

Subsequently, the chuck115moves one step along the chuck guide bar113, and the lamination and the laser irradiation are repeated.

FIG. 7is an enlarged cross-sectional view illustrating a partial region of an organic light emitting display (OLED) substrate including a patterned transfer layer.

Referring toFIG. 7, a transfer layer pattern77ais located on a pixel electrode59exposed in an opening60aof the OLED substrate described in conjunction withFIG. 4. The transfer layer pattern77amay be an emission layer. Further, the transfer layer pattern77amay further include at least one layer selected from a group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

FIG. 8is a cross-sectional view of a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention. The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, except for the following descriptions.

Referring toFIG. 8, a lamination unit150may further include an exhaust port151dfor exhausting a gas discharged on a chuck115of an outer periphery of a body151. The exhaust port151dis connected to an exhaust pump.

In this case, a compression gas Ca injected into a cavity151afrom a gas injection port151bis discharged through a gas discharge port151c. At this time, a donor film70may be laminated on an acceptor substrate50by means of the pressure of the compression gas Ca, and the gas discharged through the gas discharge port151cis exhausted through the exhaust port151d, thereby forming a predetermined gap between the body151and the donor film70. The gas discharged through the gas discharge port151cmay escape through the exhaust port151das well as the exterior of the lamination unit150.

FIG. 9is a cross-sectional view of a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention. The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, except for the following descriptions.

Referring toFIG. 9, a gas injection port151eof a lamination unit passes through an upper portion of a body151of the lamination unit. In addition, a gas discharge port151cpasses through a lower portion of the body151. In this case, the laser irradiated from a laser irradiator130may be irradiated on the donor film70by passing through the gas injection port151e, the cavity151a, and the gas discharge port151c. Therefore, the gas injection port151e, the cavity151a, and the gas discharge port151cmay constitute a light transmission part. The laser induced thermal imaging apparatus may not require the light transmission window155(seeFIG. 1), unlike the laser induced thermal imaging apparatus described in conjunction withFIG. 1.

The compression gas Ca injected into the cavity151afrom the gas injection port151eis discharged through the gas discharge port151c. At this time, the donor film may be laminated on the substrate by means of the pressure of the compression gas Ca, and the gas discharged through the gas discharge port151cis exhausted to the exterior of the lamination unit150, thereby forming a predetermined gap between the body151and the donor film70.

FIG. 10is a cross-sectional view of a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention. The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, except for the following descriptions.

Referring toFIG. 10, the apparatus further includes guide rolls145and146for closely adhering the donor film70on the acceptor substrate50to at least one side of the lamination unit150. The guide rolls145and146function to press the donor film70to closely adhere the donor film70on the acceptor substrate50. As a result, the donor film70may be readily laminated on the acceptor substrate50.

FIG. 11is a cross-sectional view of a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention.

The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, except for the following descriptions.

Referring toFIG. 11, a sidewall of the lamination unit body151includes an upper sidewall and a lower sidewall, which are connected to each other by means of an elastic body153. As a result, even when the lamination unit150is too closely located on the donor film70, it is possible to maintain a uniform gap between the body151and the donor film70due to the elastic body153. Specifically, in order to sufficiently laminate the donor film70on the substrate50, preferably, the lamination unit150is closely located on the donor film70. However, since the substrate50may have unevenness due to a structure on its surface, and the lamination unit body151may be partially in contact with the donor film70, in this case, friction between the lamination unit body151and the donor film70may be generated. The donor film70may be damaged due to generation of the friction. However, since the elastic body153may shrink or release the sidewall of the lamination unit body151depending on the pressure of the gas exhausted to the exterior of the lamination unit150through the gas discharge port151c, even though the surface of the substrate50has the unevenness, it is possible to form a uniform gap between the body151and the donor film70.

For this, more preferably, a nozzle part154including a nozzle154amay be attached to the gas discharge port151cof the lamination unit body151. The nozzle154ahas a size smaller than that of the gas discharge port151cto more effectively laminate the donor film70, the nozzle part154is subjected to force in a direction of the donor film70due to the pressure P of the compression air Ca injected into the cavity151afrom the gas injection port151b, and the nozzle part154is subjected to force due to the pressure of the gas discharged to the exterior of the lamination unit150through the nozzle154a, thereby forming a predetermined gap between the nozzle part154and the donor film70. Further, although the surface of the substrate50has the unevenness due to the elastic body153, it is possible to form a uniform gap between the body151and the donor film70. As a result, it is possible to minimize friction between the lamination unit150and the donor film70.

Differently from this, the same effect may be obtained even when the nozzle part154is made of an elastic material without individual elastic body153.

Preferably, the lamination unit150includes a light transmission window155installed at an upper portion of the body151, which is in contact with the cavity151a. In this case, the laser passes through the light transmission window155, the cavity151a, and the nozzle154ato be irradiated on the donor film70. In addition, the gas injection port151bmay pass through an upper sidewall of the body151.

FIG. 12is a cross-sectional view of a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention. The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, except for the following descriptions.

Referring toFIG. 12, the lamination unit150further includes a pipe-shaped piston156attached to a lower end of the lamination unit body151, i.e., the gas discharge port of the lamination unit body151. The piston156is movable up and down along the lamination unit body151. At this time, a head part of the piston156is subjected to force in a direction of the donor film70, i.e., a downward direction, due to the pressure P of the compression air Ca injected into the cavity151afrom the gas injection port151b, and the piston156is subjected to force in an upward direction due to the pressure of the gas discharged to the exterior of the lamination unit150through an inner part of the piston, thereby forming a predetermined gap between the piston156and the donor film70. In addition, since the piston156is movable up or down along the lamination unit body151, even when the lamination unit150is too closely located on the donor film70, it is possible to maintain a uniform gap between the body151and the donor film70due to the pressure of the gas exhausted to the exterior of the lamination unit150through the inner part of the piston. As a result, it is possible to minimize friction between the lamination unit150and the donor film70.

Further, a nozzle part157including a nozzle157amay be additionally attached to a lower portion of the pipe-shaped piston156. The nozzle part157has functions similar to the nozzle part154of the laser induced thermal imaging apparatus as described in conjunction withFIG. 11.

FIG. 13is a partially exploded perspective view schematically illustrating a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention, andFIG. 14is a cross-sectional view taken along the line I-I′ inFIG. 13. Differently from the laser induced thermal imaging apparatus described in conjunction withFIGS. 1 to 7, the laser induced thermal imaging apparatus in accordance with the embodiment employs a donor film covering an entire surface of the acceptor substrate.

Referring toFIGS. 13 and 14, a chuck115fixes an acceptor substrate50to be located on the chuck115. A donor film70-1is disposed on the acceptor substrate50. At least two corners of the donor film70-1are preferably fixed to a frame80. As a result, the donor film70-1may maintain an appropriate tension, and it is possible to maintain a uniform gap between the donor film70-1and the acceptor substrate50at edges of the donor film70-1. In this case, preferably, the chuck115also fixes the frame80.

Differently from the drawings, the lamination unit150of the embodiment may include at least one of particular components of the lamination unit described in conjunction withFIGS. 8 to 12.

Hereinafter, a laser induced thermal imaging method using the laser induced thermal imaging apparatus in accordance with an embodiment of the present invention will be described in conjunction withFIGS. 13 and 14.

Referring toFIGS. 13 and 14, an acceptor substrate50is located on a chuck115. The acceptor substrate50may be an OLED substrate described in conjunction withFIG. 4. A donor film70-1, at least two corners of which are fixed to a frame80, is located on the acceptor substrate50. Locating the donor film70-1on the acceptor substrate50may be performed as the chuck115fixes the frame80. The donor film70-1includes at least a light-heat conversion layer73(seeFIG. 3) and a transfer layer77, and the transfer layer77is located opposite to the acceptor substrate50.

Next, a lamination unit150moves downward along a lamination unit guide bar142. As a result, the donor film70-1under the lamination unit150is also movable onto the acceptor substrate50.

Continuously, a compression gas Ca is injected into a cavity151athrough a gas injection port151bof the lamination unit150. The compression gas injected into the cavity151ais discharged through a gas discharge port151c. At this time, the donor film70-1may be laminated on the acceptor substrate50by the pressure P of the compression gas, and the gas discharged through the gas discharge port151cis exhausted to the exterior of the lamination unit150, thereby forming a predetermined gap between the body151and the donor film70-1.

In this case, although bubbles are generated between the acceptor substrate50and the donor film70-1due to the donor film70-1having an appropriate tension by virtue of the frame80, the bubbles may escape from the donor film70-1and the acceptor substrate50located adjacent to a portion where the lamination is not performed. As a result, it is possible to prevent transfer failures due to the bubbles.

Next, a laser beam is emitted from a light source131(seeFIG. 2) of a laser irradiator130to pass through a projection lens137. The laser beam passed through the projection lens137is irradiated on the donor film70-1through a light transmission part of the lamination unit150, i.e., a light transmission window155, the cavity151a, and the gas discharge port151c. At this time, at least a portion of the transfer layer77is transferred on the acceptor substrate50at a region of the donor film70-1where the laser beam is irradiated. As a result, a patterned transfer layer77ais formed on the acceptor substrate50.

At this time, a laser irradiator base125moves continuously in a Y-direction along a laser guide bar123. Therefore, the laser irradiator130installed at the laser irradiator base125, a lamination unit base141connected to the laser irradiator base125, and the lamination unit150installed at the lamination unit base141also continuously move in the Y-axis direction. On the other hand, the donor film70-1is fixedly located on the chuck115by the frame80. As a result, the lamination and the laser irradiation may be continuously performed in the Y-direction. At this time, the lamination unit150may move on the donor film70-1without friction caused by a direct contact with the donor film70-1, since a gap is generated between the body151and the donor film70-1.

In addition, the laser irradiator130continuously irradiates a laser beam. Therefore, the transfer layer pattern77ais continuously generated on the acceptor substrate50along the Y-axis direction.

When the laser irradiator130arrives at an edge of the acceptor substrate50, the compression gas is not supplied to the lamination unit150, and the lamination unit150moves upward along the lamination unit guide bar142. As a result, the donor film70under the lamination unit150is detached from the acceptor substrate.

Next, the chuck115moves one step along the chuck guide bar113, and the laser irradiation process is repeated.

FIG. 15is a partially enlarged perspective view schematically illustrating a laser induced thermal imaging apparatus in accordance with another embodiment of the present invention. The laser induced thermal imaging apparatus in accordance with the embodiment is similar to the laser induced thermal imaging apparatus described in conjunction withFIG. 13, except for the following descriptions.

Referring toFIG. 15, a lamination unit150-1has a line shape extending in a Y-direction crossing a chuck115. Therefore, a donor film70-1may be laminated on an acceptor substrate50in a Y-direction crossing the chuck115in an extended manner. Further, a body of the lamination unit150-1may include a plurality of compression gas injection ports to uniformly supply the compression gas into the cavity of the lamination unit. In this case, a laser irradiator130may continuously irradiate a laser beam while moving along the lamination unit150-1in the Y-direction. As a result, the laser beam may be irradiated along the laminated donor film in the Y-direction.

Differently from the drawings, the lamination unit150-1of the embodiment may include at least one of particular components of the lamination unit described in conjunction withFIGS. 8 to 12.

As can be seen from the foregoing, the donor film may be sufficiently laminated on the acceptor substrate without generating friction between the transfer layer of the donor film and the acceptor substrate, and it is possible to obtain an excellent transfer pattern profile by irradiating the laser beam on the sufficiently laminated donor film.

Although the present invention has been described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that a variety of modifications and variations may be made to the present invention without departing from the spirit or scope of the present invention defined in the appended claims, and their equivalents.