JP2008153280A - Light-emitting device and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which can suppress overheating and produce sufficient amount of light for exposure, and to provide a printer. <P>SOLUTION: The light-emitting device is provided with a plurality of organic EL elements 20A that is arranged like an array at the specified spacing. The organic EL element 20A is provided with an organic EL element 20A that is arranged on an element substrate 21 and is sealed tight for water and an optical guide 50 wherein a wedge-shaped optical guide 57 is formed to reflect/collect lights emitted from the organic EL element 20A and to radiate them in the specified direction. The element substrate 21 and the optical guide 50 are bonded by a sealing agent 81 containing a gap agent, and an area surrounded by the organic EL element 20A, the wedge-shaped optical guide 57 and the sealing agent 81 is filled with a liquid optical guide medium 58. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting device and a printing apparatus used for exposure such as printing.

2. Description of the Related Art Conventionally, printing apparatuses that use a light emitting device including an organic EL element for exposure are known. As a technique related to this, for example, Patent Document 1 discloses an exposure apparatus and an image forming apparatus including an organic EL element. In the technique disclosed in Patent Document 1, an organic EL element and a photoconductor are installed at a certain distance through a lens, and static light is placed on the photoconductor by focused light from the organic EL element. An electrostatic latent image is formed.
JP 2004-327217 A

  By the way, since the light emitting element utilized for a printing apparatus emits light with high brightness, it generates heat and causes deterioration.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light-emitting device and a printing apparatus that can suppress overheating and obtain a sufficient amount of light for exposure in a printing apparatus or the like.

In order to achieve the above object, a light emitting device according to the first aspect of the present invention comprises:
An element substrate on which a light emitting element is disposed;
A counter substrate facing the element substrate;
A light guide provided between the element substrate and the counter substrate;
A fluid medium containing a fluid liquid for cooling the light emitting element;
It is characterized by providing.

  In the light emitting device, the fluid medium is provided in the light guide unit.

  In the above light-emitting device, the light guide section includes a wedge-shaped light guide path.

  In the light emitting device, the light guide unit includes a reflective film that reflects light emitted from the light emitting element and emits the light from the element substrate.

  In the light-emitting device, the element substrate and the counter substrate are bonded to each other with a sealant.

  The light-emitting device further includes a drive circuit unit that electrically controls light emission of the light-emitting element.

  The printing apparatus includes the light-emitting device.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device which suppresses overheating and can obtain sufficient light quantity for exposure in a printing apparatus etc. can be provided.

[First embodiment]
Hereinafter, a light emitting device and a printing apparatus according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a configuration of a printing apparatus using the light emitting device according to the first embodiment. First, as shown in FIG. 1, a printing apparatus using the light emitting device according to the first embodiment is an exposure comprising a photosensitive drum 1, a light emitting device 2A according to the first embodiment, and a rod lens array 2B. The image forming apparatus includes a unit 2, a charging roller 3, an eraser light source photoconductor 4, a cleaning member 5, a developing device 6 including a developing roller 6 a, a transfer roller 8, a fixing roller 9, and a conveyance belt 11. . Note that reference numeral 7 denotes printing paper.

  The photoreceptor drum 1 is a negatively charged OPC (Organic Photo Conductor) photoreceptor (organic photoreceptor). In view of this, the charging roller 3 is a negative charger. The developing device 6 is a developing device for developing with negatively charged toner. The light emitting device 2A is configured by arranging a plurality of organic EL elements (light emitting elements) in an array, which will be described in detail later.

  By the way, in the printing apparatus shown in FIG. 1, printing is roughly performed by the following processes. First, when the charging roller 3 comes into contact with the surface of the rotating photosensitive drum 1, the contacted surface of the photosensitive drum 1 is uniformly charged with a negative potential. Subsequently, the light emitting device 2A irradiates the photosensitive drum 1 with light through the rod lens array 2B, and an electrostatic latent image is formed on the photosensitive drum 1. Thereafter, the developer 6 attaches toner to the electrostatic latent image. Then, the toner attached to the electrostatic latent image is transferred to the printing paper 7 by the transfer roller 8. Hereinafter, such a printing process will be described in detail.

  First, the photosensitive drum 1 is initialized to a negative potential supplied from a charging power source (not shown) and relatively close to or equal to a developing voltage output from a developing device 6 described later. A charging voltage is applied by the charging roller 3. As a result, the peripheral surface of the photosensitive drum 1 is uniformly negatively charged and is initialized in terms of potential (becomes an initialized charging state).

  Then, optical writing (exposure) according to the printing information is performed on the photosensitive drum 1 whose peripheral surface has been initialized and charged by the light emitting device 2A. As a result, the initialization charging portion that remains in the initialization charged state because no exposure is performed, and the exposure charging voltage of about −50 (V) that is a negative potential relatively higher than the initialization charging portion by the exposure. Is formed on the peripheral surface of the photosensitive drum 1.

  Here, the toner charged in the developing unit 6 and charged to a weak negative potential is rotated and conveyed by the developing roller 6a to the opposing portion between the developing roller 6a and the photosensitive drum 1. At this time, the developing roller 6a is applied with a developing voltage of about −250 (V), which is lower than the exposure charging unit, from a power source (not shown). Therefore, the exposure charging portion of about −50 (V) of the electrostatic latent image on the photosensitive drum 1 is about 200 (V) higher than the development voltage, and the initialization charging portion is different from the development voltage. Is a voltage whose absolute value is sufficiently smaller than 200 (V).

  Due to the difference in potential difference from the developing voltage in these electrostatic latent images, the exposure charging portion in the electrostatic latent image having a positive polarity relative to the developing roller 6a is charged with a negative polarity. On the other hand, the toner image does not adhere to the initialization charging portion because an electric field that attracts the toner electrostatically does not occur in the initialization charging portion. The toner image is conveyed to a transfer portion where the photosensitive drum 1 and the transfer roller 8 face each other by the rotation of the photosensitive drum 1.

  The toner adhesion amount (developed image density) in the toner image formed as described above is generated according to the exposure amount of the photosensitive drum 1 by the light emitting device 2A. It is determined by the potential on the peripheral surface, that is, the potential difference from the development voltage.

  By the way, as described above, when the toner image is transported to the transfer unit, the printing paper 7 is transported to the transfer unit by the transport belt 11. In the transfer unit, the toner image is transferred onto the printing paper 7 by the transfer roller 8. The printing paper 7 to which the toner image is transferred in this way is further conveyed downstream, and after the toner image is thermally fixed by the fixing roller 9, the printing paper 7 is discharged to the outside of the printing apparatus. The

  Hereinafter, the basic structure of the light emitting device 2A will be described with reference to FIGS. Here, the light-emitting device 2A includes a plurality of organic EL elements 20A that mainly emit light, a light guide unit 50 that sets the traveling direction of light emitted by the organic EL elements 20A to a predetermined direction, and emits the light. A drive circuit unit 40A that electrically controls light emission of the organic EL element 20A is provided.

  As shown in FIG. 2, the organic EL element 20 </ b> A is formed on an element substrate 21 made of glass or the like, and is sealed by a counter substrate 28 made of glass or the like disposed to face the element substrate 21. Specifically, as the organic EL element 20A on the element substrate 21, a light-reflective pixel electrode 23, a hole transport layer (HTL) 24, a light-emitting layer 25, an electron transport layer (ETL) 26, and a light-transmitting layer are provided. The counter electrode 27 is formed in this order. Here, the hole transport layer 24, the light emitting layer 25, and the electron transport layer (ETL) 26 are organic EL layers containing an organic compound. The organic EL layer is not limited to the above, and may be, for example, a hole transport layer and an electron transport light emitting layer, or only a hole transport / electron transport light emitting layer, or a hole transport light emitting layer and an electron transport layer. In addition, a carrier transport layer may be appropriately interposed therebetween, or a combination of other carrier transport layers may be used.

  The pixel electrode 23 functions as an anode, and is formed of a reflective metal layer such as an aluminum alloy provided on the lower layer side, and tin-doped indium oxide (ITO) or zinc-doped indium oxide provided on the upper layer side. It may be a laminated structure with a transparent conductive metal oxide layer having a transparent electrode material, or may be a single layer of a reflective metal layer such as an aluminum alloy.

  The counter electrode 27 functions as a transparent cathode, and has an electron injection layer having a low work function such as barium, magnesium, or lithium provided on the lower layer side, and a transparent conductive metal oxide similar to the above provided on the upper layer side. A laminated structure of layers may be used.

  When the pixel electrode 23 is a cathode and the counter electrode 27 is an anode, the carrier transport layer in contact with the pixel electrode 23 is an electron transport layer, and the carrier transport layer in contact with the counter electrode 27 is a hole transport layer. Become a layer.

  Then, by applying a predetermined voltage between the pixel electrode 23 and the counter electrode 27, holes are injected from the pixel electrode 23, and electrons are injected from the counter electrode 27 into the light emitting layer 25. In the light emitting layer 25, holes and electrons recombine to emit light. The light 100 generated by the light emission passes through the counter electrode 27 made of ITO and is completely diffused and radiated in the direction of the counter substrate 28. The counter electrode 27 may be a single electrode common to the plurality of organic EL elements 20A.

  By the way, in the first embodiment, a light beam having a small diameter is formed on the photosensitive drum 1 separated by a millimeter order distance from the exposure unit 2 by the exposure unit 2 including the light emitting device 2A and the rod lens array 2B. Create a light beam that forms spots and resolves each dot. Hereinafter, the detailed configuration of the exposure unit 2 will be described with reference to FIG.

  In the light emitting device 2A, a plurality of organic EL elements 20A are arranged in an array. Here, the organic EL element 20 </ b> A exists between the element substrate 21 and the counter substrate 28, and light whose traveling direction is controlled by the light guide unit 50 is emitted from the element substrate 21. Radiates from the region 33 to the outside of the element substrate 21. Therefore, although the organic EL element 20A is not shown in FIG. 3, since the organic EL element 20A and the light emitting region 33 have a one-to-one correspondence, the arrangement of the organic EL elements 20A is easy from the same figure. Can be guessed. Thus, in the light emitting device 2A, the organic EL elements 20A are arranged so that the light emitting region 33 of the element substrate 21 faces the rod lens array 2B.

  In the light emitting device 2A, a plurality of organic ELs are arranged so as to be aligned in the main scanning direction of the exposure scanning to the photosensitive drum 1 shown in FIG. 1 (the width direction of the photosensitive drum 1, that is, the width direction of the printing paper 7). The element 20A is disposed to form an organic EL array. If the printing apparatus is a printing apparatus capable of printing at a printing density of 1200 dpi (dots / inch) to the full width using, for example, A4 size printing paper in the vertical direction, this organic EL array is approximately 14,000 pieces. The organic EL element 20A is provided. A pulse voltage in accordance with print information output from a host device (not shown) is applied to each of the organic EL elements 20A. That is, each organic EL element 20A is selectively controlled to emit light.

  The light emitting region 33 is a region provided in the element substrate 21 in order to emit light emitted from the organic EL element 20A to the outside of the element substrate 21.

  The organic EL element 20A is electrically connected to the host device (not shown) by control cables 31A and 31B as shown in FIG. Here, the connection method between the control cables 31A and 31B and the organic EL element 20A may be any connection method as long as it can drive the organic EL element 20A.

  By the way, the element substrate 21 and the counter substrate 28 are bonded to each other by a sealing agent 81 (details will be described later) through a sealing resin 70. 6 to 8, the sealing agent 81 is applied so as to surround the organic EL element 20A.

  Hereinafter, the detailed structure of the organic EL element 20A included in the light emitting device 2A according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 4, the organic EL element 20 </ b> A is formed on the element substrate 21 and sealed by the counter substrate 28. Here, the counter substrate 28 is coated with a sealing resin 70 as shown in FIG. A plurality of light guide portions 50 are formed in the sealing resin 70 so as to correspond to the respective organic EL elements 20A. The sealing resin 70 has a recess that has a predetermined shape such that a fluid light guide medium 58 described later functions as a light guide path. An organic EL element 20 </ b> A is formed between the element substrate 21 and the light guide unit 50. Further, a drive circuit unit 40 is electrically connected to the organic EL element 20A. Hereinafter, the structure of the organic EL element 20A including the organic EL element 20A, the light guide unit 50, and the drive circuit unit 40 will be described in detail.

  The organic EL element 20A includes the pixel electrode 23, the HTL 24, the EL 25, the ETL 26, and the counter electrode 27. The details of the organic EL element 20A are as described with reference to FIG. Further, two insulating banks 35 are provided adjacent to the organic EL element 20A. The bank 35 prevents damage due to the organic EL element 20 </ b> A being pressed in the stacking direction and a short circuit between the pixel electrode 23 and the counter electrode 27.

  Here, a gap agent (not shown) having a predetermined diameter is provided in a region between the sealing agent 81 and the bank 35, and the element substrate 21 and the counter substrate are formed by the gap agent (not shown). 28 is kept at a predetermined interval. Of course, a gap agent may be included in the sealant 81. As long as the gap agent is insulative, it may be an inorganic compound such as ceramic or a resin, and the shape is not particularly limited, such as a spherical shape or a cylindrical shape, but is not provided on the organic EL element 20A. Thus, since a space is formed between the element substrate 21 and the counter substrate 28, when the element substrate 21 and the counter substrate 28 are bonded and bonded in the manufacturing process described later. The organic EL element 20A has no fear of being crushed.

  Further, as shown in FIG. 4, an insulating protective film 46 having an insulating material such as SiNx (refractive index 1.8) is formed on the drive circuit unit 40. In a space between the element substrate 21 and the counter substrate 28 surrounded by the sealant 81, a fluid light guide medium 58 containing fluid liquid for cooling the organic EL element 20 </ b> A and the drive circuit unit 40. Is filled. In other words, the organic EL element 20 </ b> A and the drive circuit unit 40 are sealed in a watertight and airtight manner by the insulating protective film 46 and the flowable light guide medium 58. Since the drive circuit unit 40 and the insulating protective film 46 are sufficiently thinner than the thickness between the element substrate 21 and the counter substrate 28, the height of the gap agent in the region where the drive circuit unit 40 and the insulating protective film 46 are present There is almost no difference in the height of the gap agent in the non-region.

  The light guide 50 includes a reflective film 59 provided on the inner surface of a wedge-shaped recess formed in the sealing resin 70 and a wedge-shaped light guide 57 serving as a space provided in the recess surrounded by the reflective film 59. And an emission path 53 serving as a space for guiding light propagating in the wedge-shaped light guide path 57 to the light emission region 33, and a flowable light guide medium 58 filled in the wedge-type light guide path 57 and the emission path 53. . For this reason, since the fluid light guide medium 58 becomes a medium for propagating light emitted from the organic EL element 20A, it must have good light transmittance and is preferably colorless.

  Here, the reflection film 59 is formed with a condensing reflection surface 55 and a downward radiation reflection surface 56. The condensing reflection surface 55 is disposed above the organic EL element 20A, and is inclined so that incident light is emitted downward toward the radiation reflection surface 56 side. The downward radiation reflection surface 56 is provided at a position corresponding to the light emission region 33, and is inclined so as to reflect incident light and emit it from the light emission region 33.

  Therefore, the light beam 51 from the organic EL element 20A travels in the fluid light guide medium 58 filled in the wedge-shaped light guide 57 as shown in FIG. Reflection between the reflection surface 55 and the pixel electrode of the organic EL element 20 </ b> A is repeated and condensed toward the downward radiation reflection surface 56, reflected by the downward radiation reflection surface 56, and provided in the element substrate 21. The light is emitted from 33. When the pixel electrode 20 does not have a reflective member and incident light is transmitted, a reflective film may be provided below the organic EL element 20A, for example, below the gate insulating layer 45.

  Examples of the fluid light guide medium 58 include fluorinated inert liquid Fluorinert (registered trademark) and silicone oil.

  More specifically, FC-3283 made by Sumitomo 3M can be mentioned as the fluorinate, and KF-96L-1cs made by Shin-Etsu Silicone can be mentioned as the silicone oil.

  The silicone oil is a chemically stable substance. Therefore, the silicone oil has an advantage that there is not much deterioration or deterioration with time due to irradiation with light generated in the organic EL element 20A. In addition, the organic EL element generates heat during light emission, and deterioration is accelerated by this heat. However, since the fluid light guide medium 58 functions as a refrigerant, the life of the organic EL element 20A can be extended. From the viewpoint of cooling, the fluid light guide medium 58 is preferably in direct contact with the organic EL element 20A. However, there is a thin sealing insulating film between the fluid light guide medium 58 and the organic EL element 20A. Also good. It is particularly preferable that the flowable light guide medium 58 has a refractive index that approximates or matches the refractive index of the adjacent member. In the case of Fluorinert, the refractive index is about 1.25 to 1.3.

  As shown in FIG. 4, the fluid light guide medium 58 is filled not only in the light guide part 50 but also in the space above the drive circuit part 40. Therefore, a sufficient amount can be filled between the element substrate 21 and the counter substrate 28, and a sufficient cooling effect can be obtained.

  The greater the difference in refractive index between two adjacent transparent media, the greater the degree of refraction at the interface between the transparent media, making it difficult to set the light to be guided in a predetermined direction. As described above, the boundary region between the organic EL element 20A and the light guide unit 50 is filled with the flowable light guide medium 58, so that the boundary region between the organic EL element 20A and the light guide unit 50 has low refraction. It is easy to control the traveling direction of light in the light guide unit 50. For this reason, it is possible to prevent light loss caused by the gas layer interposed in the optical path until the light emitted from the organic EL element 20A enters the light guide 50.

  The drive circuit unit 40 includes a thin film transistor having a drain electrode 41, a source electrode 42, a gate electrode 43, a semiconductor 44, and a gate insulating layer 45, and is covered with an insulating layer 46. The source electrode 42 is connected to the pixel electrode 23 of the organic EL element 20A. There may be a plurality of thin film transistors for each organic EL element 20A. The drive circuit unit 40 will be described later with reference to FIG.

  By the way, in general, organic EL elements are vulnerable to moisture. Therefore, in order to prevent the adverse effect of moisture on the organic EL element, in the present embodiment, the organic EL element 20A is formed between the element substrate 21 and the counter substrate 28 as shown in FIG. . As a result, the organic EL element 20A does not come into direct contact with moisture and outside air from above and below. Then, from the lateral direction, moisture and outside air can be blocked by the sealant 81 and the flowable light guide medium 58.

  In such a structure, in order to make the sealing of the organic EL element 20A in the lateral direction good, the distance from the organic EL element 20A to the sealing agent 81 is increased, and the lateral distance of the fluid light guide medium 58 is increased. Even if it is filled, the distance from the organic EL element 20A to the light emitting region 33 does not become long in the lateral direction, that is, since no light is emitted from the sealant 81 of the light emitting device 2A. The optical path length of 51 does not have to be long.

  Hereinafter, main processes for manufacturing the organic EL element 20 </ b> A and the light guide unit 50 will be described.

  On the element substrate 21 on which the drive circuit unit 40 is formed, a plurality of organic EL elements 20A are formed in a line so as to be aligned in the main scanning direction of the exposure scanning to the photosensitive drum 1 shown in FIG. Thus, an organic EL array is formed.

  First, a plurality of the organic EL elements 20A are formed on the element substrate 21. Each organic EL element 20A has a shape when viewed from the lower side of the element substrate 21 to be a rectangle whose longitudinal direction is the sub-scanning direction (paper transport direction). Therefore, the plurality of organic EL elements 20A are arranged along the main scanning direction (short direction). As a result, the light emitting area of the organic EL element 20A can be relatively increased even if the interval between the organic EL elements 20A in the main scanning direction is narrowed to have a high definition pitch.

  Further, after the organic EL elements 20A and the drive circuit section 40 are arranged in an array on the element substrate 21, a sealant made of a UV curable resin immediately before the element substrate 21 is bonded to and bonded to the counter substrate 28. 81 is applied to the element substrate 21 so as to surround the array of the organic EL elements 20A and the drive circuit section 40. When applying the sealant 81 to the element substrate 21, it is not applied so as to completely surround the organic EL element 20A and the drive circuit unit 40, but a predetermined one as shown in FIG. The location is provided with a sealant opening 85 where the sealant 81 is not applied. The element substrate 21 thus arranges the array of the organic EL elements 20A and the drive circuit unit 40 and seals the array of the organic EL elements 20A and the drive circuit unit 40 with the sealant 81.

  Here, a method of forming the light guide 50 will be described. First, the same wedge shape as the wedge light guide 57 shown in FIG. 5 is imprinted in an array on the sealing resin 70 coated on the counter substrate 28. Thus, the reflective film 59 made of metal is formed on the wedge-shaped light guide path 57 imprinted in the sealing resin 70 in a concave manner. Note that the organic EL light emitting surface 61 shown in FIG. 5 is the upper surface (the surface facing the wedge-shaped light guide 57) of the organic EL element 20A. The reflective film 59 is not electrically short-circuited with the organic EL element 20 </ b> A and the drive circuit unit 40 even when the element substrate and the counter substrate are bonded, and has a gap so that the fluid light guide medium 58 can be filled. Is preferred.

  Subsequently, the element substrate and the counter substrate are bonded to each other with the sealant 81 before curing in a state where a predetermined interval maintained by the gap agent (not shown) is maintained in accordance with a predetermined alignment mark. . Then, the sealing agent 81 is cured by irradiating ultraviolet rays, and the element substrate and the counter substrate are bonded together (hereinafter, the substrate obtained by the bonding is referred to as a panel).

  Thereafter, the inside of the manufacturing apparatus is under a pressure lower than the atmospheric pressure (hereinafter referred to as “reduced pressure”), and the inside surrounded by the sealing agent 81 and the surrounding exterior are set to the same pressure as under reduced pressure. Subsequently, as shown in FIG. 7, the sealing agent opening 85 in the panel 82 is immersed in a flowable light guide medium tank 86 filled with the flowable light guide medium 58 to perform a flowable light guide medium injection step. Start. Hereinafter, the fluid light guide medium injection step will be described.

  First, the sealant opening 85 is immersed in the fluid light guide medium tank 86 under reduced pressure so as to contact the fluid light guide medium 58. Subsequently, the pressure in the manufacturing apparatus is set to a higher atmospheric pressure, for example, atmospheric pressure than that under reduced pressure. As a result, the pressure in the space surrounded by the sealant 81 becomes lower than the pressure outside the space, and the fluid light guide medium 58 is filled from the sealant opening 85.

  After the fluid light guide medium 58 is filled in the space surrounded by the sealant 81, the panel 82 is taken out from the fluid light guide medium tank 86 and UV is applied to the sealant opening 85. Sealing is performed with a sealing cured resin 83 that is applied with a cured resin and cured by irradiation with ultraviolet rays. In this way, the flowable light guide medium 58 is sealed between the element substrate and the counter substrate, and a structure as shown in FIGS. 6A and 6B can be obtained.

  Although the gap between the element substrate and the counter substrate is controlled by the sealing resin 70 and the gap agent (not shown), the bank 35 is brought into contact with the opposing sealing resin 70 to replace the gap agent. Of course, it may be controlled by the height of the bank 35. Further, although the sealing agent 81 is provided on the edge of the sealing resin 70, the periphery of the sealing resin 70 may be shifted to the inside of the counter substrate 28 so that the sealing agent 81 surrounds the periphery of the sealing resin 70. .

  Hereinafter, a configuration example of the drive circuit unit 40 in the case where the organic EL element 20A is driven by active matrix drive will be described with reference to FIGS. 8A and 8B. The drive circuit unit 40 is not a feature of the present invention and will be described briefly.

  FIG. 8A shows a side sectional view of the panel 82. As shown in the figure, the drive circuit unit 40 includes, for each pixel, a selection transistor 101, a drive transistor 103 connected to the selection transistor 103 and the organic EL element 20A, and a capacitor 105 for data storage. Then, the selection transistor and the drive transistor are controlled so that each organic EL element 20A emits light or no light as appropriate. The source of the selection transistor 101 and the gate of the driving transistor 103 are connected through a contact hole 110. The counter electrode 27 is fixed at, for example, 0 (V), and the pixel electrode 23 is electrically connected to the source electrode 42 of the driving transistor. Note that the HTL 24, the EL 25, and the ETL 26 are collectively expressed as one layer in FIG. 8 as the light emitting layer 200 for the convenience of the size of the page.

  FIG. 8B is a top sectional view of the panel 82. As shown in the figure, the counter electrode 27 is a single common electrode common to all pixels, and extends in the main scanning direction.

  By the way, since an organic EL element generally requires a large current for driving, a current supply line 111 for supplying a large current to the driving transistor 103 is provided in addition to the data line 107 and the scanning line 109 for selecting a light emitting pixel. Cost.

  With such a structure, the light emitting layer which is a thin film layer in a region sandwiched between the counter electrode 27 and the pixel electrode 23 emits light by a current flowing through the light emitting layer.

  As described above, according to the present embodiment, the fluid light guide medium can suppress overheating of the organic EL element and obtain a sufficient amount of light for exposure in a printing apparatus or the like.

  Further, since the fluid light guide medium has a function also serving as a light guide path, the light emitting section itself can be reduced in size.

  Conventionally, a light emitting element is covered with a sealing resin in order to suppress deterioration of the light emitting element formed on the element substrate. However, when the element substrate is bonded to the counter substrate, the sealing resin that becomes a bonding surface is used. If there are irregularities on the surface or the bonding surface of the sealing substrate, the pressing force concentrates on the convex parts, and the organic EL element has a structure in which thin films are laminated. As a result, the anode and the cathode positioned above and below may be short-circuited.

  On the other hand, according to the structure and the manufacturing method of the present embodiment, even in bonding by bonding the element substrate 21 and the counter substrate 28, there is no fear of being crushed because there is a space on the organic EL element. . Then, in the subsequent fluid light guide medium injection step, the fluid light guide medium is filled without a gap due to the pressure difference between the inside and outside of the panel, so that even if the opposing surfaces of the element substrate and the counter substrate are uneven, The organic EL element is not pressed by the convex portion.

  And since the fluid light guide medium is interposed, since there is no low refraction air, the difference in refractive index at the interface of the same light portion is reduced, and light can be conducted well.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to embodiment mentioned above, Of course, a various deformation | transformation and application are possible within the range of the summary of this invention. is there.

  For example, an organic EL element is applied as a light emitting element, but any other element may be applied as long as it generates heat, and the printing apparatus emits light with high luminance. This is also effective in an LED having an inorganic material.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

1 is a diagram illustrating a configuration example of a printing apparatus using a light emitting device according to an embodiment of the present invention. The figure which shows the structure of the light-emitting device in an organic EL element. FIG. 3 is a diagram illustrating an appearance of an exposure unit of a printing apparatus using a light emitting device according to an embodiment of the invention. The figure which shows the structure of the organic EL element in the light-emitting device which concerns on one Embodiment of this invention. The figure which shows the shape of the wedge-shaped light guide of the organic EL element which the light-emitting device which concerns on one Embodiment of this invention has. The figure which shows the bonding structure of an element substrate and a counter substrate. The figure which shows a fluid light guide medium injection | pouring process. (A) is side surface sectional drawing of a panel. (B) is a top sectional view of the panel.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 2A ... Light-emitting device, 2B ... Rod lens, 2 ... Exposure part, 3 ... Charging roller, 4 ... Eraser light source photoconductor, 5 ... Cleaning member, 6a ... Developing roller, 6 ... Developer, 7 ... Printing paper 8 ... Transfer roller 9 ... Fixing roller 11 ... Conveying belt 20,20A ... Light emitting device 21 ... Element substrate 23 ... Pixel electrode 24 ... Hole transport layer 25 ... Light emitting layer 26 ... Electronic Transport layer 27 ... Counter electrode 28 ... Counter substrate 31A, 31B ... Control cable 33 ... Light emitting area 35 ... Bank 40 ... Drive circuit section 41 ... Drain electrode 42 ... Source electrode 43 ... Gate electrode 44 ... Semiconductor, 45 ... Gate insulation layer, 46 ... Insulation layer, 50 ... Light guide part, 51 ... Light beam, 55 ... Condensing reflection surface, 56 ... Downward radiation reflection surface, 57 ... Wedge Type light guide, 58 ... Fluid light guide medium, 59 ... Reflective film, 61 ... EL light emitting surface, 70 ... Sealing resin, 81 ... Sealing agent, 82 ... Panel, 83 ... Sealing film, 85 ... Sealing agent opening 86 ... Fluid light guide medium tank, 100 ... EL element drive circuit, 101 ... Switch TFT, 103 ... Drive transistor, 105 ... Capacitor, 107 ... Data line, 109 ... Scan line, 111 ... Current supply line, 200 ... Light emission layer.

Claims (7)

An element substrate on which a light emitting element is disposed;
A counter substrate facing the element substrate;
A light guide provided between the element substrate and the counter substrate;
A fluid medium containing a fluid liquid for cooling the light emitting element;
A light emitting device comprising:   The light emitting device according to claim 1, wherein the fluid medium is provided in the light guide unit.   The light-emitting device according to claim 1, wherein the light guide section includes a wedge-shaped light guide path.   The light-emitting device according to claim 1, wherein the light guide unit includes a reflective film that reflects light emitted from the light-emitting element and emits the light from the element substrate.   The light emitting device according to claim 1, wherein the element substrate and the counter substrate are bonded together by a sealing material.   The light emitting device according to claim 1, further comprising a drive circuit unit that electrically controls light emission of the light emitting element.   The printing apparatus according to claim 1, comprising the light-emitting device according to claim 1.

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