JP2007073286A - Method of manufacturing light emitting device, light-emitting device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a light emitting device equipped with a plurality of light emitting elements, of which, an organic light emitting layer hardly emits light at unintended regions by leak current, and to provide the light emitting device and electronic equipment using the same. <P>SOLUTION: The method of manufacturing a line head 1 as the light-emitting device, comprises a light emitting element-forming process forming a light emitting layer 60 made of an organic material on a whole surface of an element substrate 2 with a pixel electrode 23 formed, a process of forming a cathode 50 so as to oppose the pixel electrode 23 on the light-emitting layer 60 formed, and a degradation process of degrading the light emitting layer 60 existing in a region other than that in which the cathode is formed. In the degradation process, light is irradiated from an opposite side to a side in touch with the light emitting layer of the cathode 50 to degrade the light emitting layer 60 not covered with the cathode 50. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light-emitting device having an organic EL (electroluminescence) element, a light-emitting device, and an electronic apparatus using the same.

  As a method for manufacturing a light-emitting device having an EL element, a monochromatic organic EL element in which an anode layer as a first electrode, a hole injection layer, a light-emitting layer, and a cathode layer as a second electrode are stacked on a substrate A method of forming at least a light emitting layer by a spin coating method is known in an organic EL device having the above (Patent Document 1).

  There is also known an image forming apparatus having a line head in which a plurality of monochromatic organic EL elements (light emitting elements) are arranged on a line, a charging unit provided around an image carrier, a developing unit, and a transfer unit. (Patent Document 2).

JP 2002-124376 A (pages 5-6) JP 2005-153372 A (pages 15 to 17)

  In an organic EL device having an organic EL element in which a light emitting layer is formed on the entire surface of a hole injection layer using a spin coating method as described above, a region other than a pixel region that emits light (a portion where an anode layer and a cathode layer overlap) There is also a light emitting layer. Therefore, when the drive current flows out (leaks) outside the pixel region to be emitted, a so-called crosstalk phenomenon may occur in which the light emitting layer existing in the region other than the pixel region emits light unintentionally. there were.

  In addition, in an image forming apparatus having a line head using such an organic EL element as a light emitting element, there is a problem that a clear image cannot be obtained due to a problem such as an image blurring due to the occurrence of crosstalk. It was.

  The present invention has been made in order to improve the above-described problem, and a method for manufacturing a light-emitting device including a plurality of light-emitting elements that are difficult to emit light in an unintended region of an organic light-emitting layer due to a leakage current, and the light-emitting device An object of the present invention is to provide an electronic device using the.

  A method of manufacturing a light emitting device according to the present invention is a method of manufacturing a light emitting device including a plurality of light emitting elements each having a pair of electrodes and at least an organic light emitting layer disposed between the pair of electrodes. On the substrate on which one of the electrodes is formed, a light emitting layer forming step of forming an organic light emitting layer on the entire surface, and forming the other electrode on the formed organic light emitting layer so as to face one electrode And a deterioration step of deteriorating the organic light emitting layer existing outside the region where any one of the pair of electrodes is formed.

  Leakage current refers to a current that flows toward one of a pair of electrodes of adjacent light emitting elements when a current flows between a pair of electrodes of a desired light emitting element among a plurality of light emitting elements. Point to. According to this method, in the light emitting layer forming step, the organic light emitting layer is formed on the entire surface on the substrate on which one of the pair of electrodes is formed. Then, after the other electrode is formed on the formed organic light emitting layer so as to face the one electrode, in the deterioration process, one of the pair of electrodes is applied to the organic light emitting layer formed on the entire surface. The organic light emitting layer existing outside the region where one electrode is formed is deteriorated. In the deteriorated organic light emitting layer, unintended light emission (crosstalk) is difficult to occur even when a leak current flows. That is, the region of the organic light emitting layer that emits light due to leakage current can be reduced, and a method for manufacturing a light emitting device including a plurality of light emitting elements that are difficult to emit light in an unintended region of the organic light emitting layer can be provided.

  In addition, one of the pair of electrodes is formed to have a reflection function of reflecting light emitted from the organic light emitting layer, and in the deterioration process, the electrode having the reflection function of the pair of electrodes is in contact with the organic light emitting layer. The organic light emitting layer which is not covered with the electrode which has a reflective function is deteriorated by irradiating light from the opposite side.

  According to this method, in the deterioration process, light is irradiated from the opposite side to the side of the pair of electrodes that contacts the organic light emitting layer of the electrode having the reflection function, so that the light is reflected at the electrode portion having the reflection function. Then, only the organic light emitting layer that is not covered with the electrode having the reflecting function is irradiated with light, and the organic light emitting layer can be deteriorated. That is, the organic light emitting layer existing outside the region where one of the pair of electrodes is formed can be more selectively deteriorated.

  In addition, it is preferable that either one of the pair of electrodes is formed to have a reflective layer that does not transmit ultraviolet light or light including ultraviolet light, and irradiation with light including ultraviolet light or ultraviolet light is performed in the deterioration process. . The organic light emitting layer is relatively easily degraded by ultraviolet light. According to this, since the reflective layer does not transmit ultraviolet light or light including ultraviolet light, the organic light emitting layer existing in the region not covered with the reflective layer can be easily deteriorated, and even if a leak current flows. It is possible to make it difficult to emit light.

  In the pixel region where the pair of electrodes face each other, it is preferable that a reflective layer be formed on one of the pair of electrodes. According to this, since the reflective layer is formed on one of the pair of electrodes in the pixel region where the pair of electrodes are opposed to each other, the organic light emitting layer present in the region not covered with the reflective layer in the deterioration process As a result of the deterioration, it is possible to reduce the occurrence of unintended light emission due to leakage current in a region other than the pixel region.

  Moreover, it is preferable to irradiate the said light with the irradiation amount of the grade which deactivates an organic light emitting layer in the said deterioration process. According to this, since the light is irradiated at an irradiation amount enough to deactivate the organic light emitting layer, the organic light emitting layer is deteriorated without irradiating excessive light, and unintentional light emission due to the leakage current is more efficiently performed. Can be suppressed.

  The light-emitting device of the present invention is a light-emitting device including a plurality of light-emitting elements each having a pair of electrodes and at least an organic light-emitting layer disposed between the pair of electrodes. It was manufactured using.

  According to this configuration, using the method for manufacturing a light emitting device of the present invention, a plurality of light emitting elements in which an organic light emitting layer existing in a region other than a region where one of the pair of electrodes is formed in a deterioration process is deteriorated. Accordingly, the light-emitting device in which the deteriorated organic light-emitting layer hardly emits light even when a leak current flows and so-called crosstalk is reduced can be provided.

  Another light-emitting device of the present invention is a light-emitting device including a plurality of light-emitting elements each having a pair of electrodes each having a reflection function and at least an organic light-emitting layer disposed between the pair of electrodes. The light-emitting device is manufactured using the method for manufacturing a light-emitting device according to the invention.

  According to this configuration, using the method for manufacturing a light emitting device of the present invention, in the deterioration process, the light is reflected by the electrode portion having a reflection function, and only in the organic light emitting layer existing outside the region where the electrode is formed. A light-emitting element in which the organic light-emitting layer is deteriorated when exposed to the light is provided. Therefore, even if a leak current flows, the deteriorated organic light emitting layer hardly emits light. That is, crosstalk is reduced, and light emission from the organic light emitting layer is reflected and emitted by the electrode having a reflection function in the pixel region where the pair of electrodes face each other, thereby providing a light emitting device having higher luminance. can do.

  An electronic apparatus according to the present invention includes the light-emitting device according to the present invention. According to this, it is possible to provide an electronic apparatus including a light emitting device in which crosstalk that causes the organic light emitting layer to emit light due to a leakage current is reduced.

  In the embodiment of the present invention, a line head as a light emitting device having an organic EL element and an image forming apparatus as an electronic apparatus including the line head will be described as an example.

(Line head module)
First, a line head module having a line head will be described. FIG. 1 is a perspective sectional view showing the structure of the line head module. The line head module 101 of the present embodiment includes a line head 1 in which organic EL elements as light emitting elements are arranged and arranged, a lens array 31 in which lens elements for imaging light from the line head 1 are arranged, and the line head 1. And a head case 52 for holding the outer periphery of the lens array 31, and a condensing lens 58 is affixed to the light emitting side surface of the lens array 31.

  The line head 1 and the lens array 31 are bonded and held to the head case 52 using a sealing material 54 in a state of being aligned with each other. The lens array 31 and the condenser lens 58 are pasted and integrated in an aligned state. With such a configuration, the line head module 101 is aligned with the photosensitive drum described later, so that the line head 1, the lens array 31, and the condenser lens 58 are aligned.

  FIG. 2 is a schematic diagram showing the structure of the line head. The line head 1 of the present embodiment includes a light emitting element array 3A in which a plurality of organic EL elements 3 are arranged on a long and thin rectangular element substrate 2, and a drive element 4 that drives the organic EL element 3. A group and a control circuit group 5 for controlling the driving of these driving elements 4 are integrally formed. In the present embodiment, two (two) light emitting element arrays 3A are formed, and the organic EL elements 3 in the light emitting element arrays 3A and 3A are arranged in a staggered manner. Therefore, the apparent pitch between the organic EL elements 3 in the longitudinal direction is reduced, and the resolution of the image forming apparatus described later can be improved.

  The line head 1 has a light emitting side surface facing the photosensitive drum, and the row direction of the light emitting element row 3A (the alignment direction of the light emitting elements) is arranged in parallel with the rotation axis of the photosensitive drum. It has become so.

  The organic EL element 3 includes at least an organic light emitting layer disposed between a pair of electrodes, and emits light by supplying a current from the pair of electrodes to the organic light emitting layer. A power supply line 8 is connected to one electrode of the organic EL element 3, and a power supply line 7 is connected to the other electrode via a drive element 4. The drive element 4 is composed of a switching element such as a thin film transistor (TFT) or a thin film diode (TFD). When a TFT is adopted as the drive element 4, the power supply line 8 is connected to the source region, and the control circuit group 5 is connected to the gate electrode. The control circuit group 5 controls the operation of the drive element 4, and the drive element 4 controls the energization of the organic EL element 3.

  The organic light emitting layer of the organic EL element 3 is formed so as to cover the entire surface of the element substrate 2 on which one of the pair of electrodes is formed. In addition, the organic light emitting layer existing outside the region where at least one of the pair of electrodes is formed is treated so as not to cause unintentional light emission due to the leakage current. Detailed structures and manufacturing methods of the organic EL element 3 and the driving element 4 will be described later.

  FIG. 3 is a perspective view of the lens array. This lens array 31 is composed of, for example, a SELFOC (registered trademark) lens array (trade name of Nippon Sheet Glass Co., Ltd.), and the SELFOC (registered trademark) lens element or SL elements 31a having the same configuration are arranged in a staggered manner. Two rows are arranged (arranged). Further, a gap between the SL elements 31a arranged in a staggered manner is filled with a black silicone resin 32, and a frame 34 is arranged around it. Here, the SL element 31a is a cylindrical lens element and forms an erecting equal-magnification image. By arranging (arranging) such SL elements 31a in two rows in a zigzag manner, the lens array 31 enables imaging of a wide range of images. The lens array 31 is not limited to the SELFOC (registered trademark) lens array, and may be any lens array in which lens elements for imaging light from the organic EL elements 3 (light emitting elements) are arranged. Various types can be used.

(Organic EL element and driving element)
FIG. 4 is a schematic cross-sectional view showing the structure of the organic EL element and the drive element. FIG. 2A shows a bottom emission type, and FIG. 2B shows a top emission type organic EL element. The organic EL element 3 of the present embodiment may be either a bottom emission type or a top emission type.

  As shown in FIG. 4A, the bottom emission type organic EL element 3 is sequentially formed so as to cover the pixel electrode 23 (anode) as one electrode formed on the element substrate 2 and the pixel electrode 23. The stacked hole injection layer 70 and the light emitting layer 60 as an organic light emitting layer, and the cathode (opposite) as the other electrode formed so as to face the pixel electrode 23 through the hole injection layer 70 and the light emitting layer 60. Electrode) 50.

  The pixel electrode 23 is connected to one of the three terminals of the TFT element 123 as the driving element 4 formed on the element substrate 2, and is formed of a transparent electrode material such as ITO (Indium Tin Oxide). ing.

  For the cathode 50, for example, Ca is formed to a thickness of about 20 nm, a transparent conductive film such as ITO is stacked thereon, and Al is formed to a region facing the pixel electrode 23 (pixel region) to a thickness of about 200 nm. The laminated structure electrode is made to function as a reflective layer.

  When the organic EL element 3 is a bottom emission type, the light emitted from the light emitting layer 60 is reflected by the reflective layer of the cathode 50 and is taken out from the element substrate 2 side. Therefore, the element substrate 2 is transparent or semitransparent. Is adopted. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferably used.

The element substrate 2 is provided with a circuit unit 11 for driving the organic EL element 3. That is, a base protective layer 281 mainly composed of SiO ₂ is formed on the surface of the element substrate 2 as a base, and a silicon layer 241 is formed thereon. A gate insulating layer 282 mainly composed of SiO ₂ and / or SiN is formed on the surface of the silicon layer 241.

In the silicon layer 241, a region overlapping with the gate electrode 242 with the gate insulating layer 282 interposed therebetween is a channel region 241a. The gate electrode 242 is a part of a scanning line (not shown). On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surface of the gate insulating layer 282 that covers the silicon layer 241 and on which the gate electrode 242 is formed.

  Further, in the silicon layer 241, a low concentration source region 241b and a high concentration source region 241S are provided on the source side of the channel region 241a, while a low concentration drain region 241c and a high concentration drain are provided on the drain side of the channel region 241a. The region 241D is provided to form a so-called LDD (Light Doped Drain) structure. Among these, the high-concentration source region 241S is connected to the source electrode 243 through a contact hole 243a that opens over the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured as a part of a power supply line (not shown). On the other hand, the high-concentration drain region 241D is connected to the drain electrode 244 made of the same layer as the source electrode 243 through a contact hole 244a that opens through the gate insulating layer 282 and the first interlayer insulating layer 283.

  On the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed, for example, a planarizing film 284 mainly composed of an acrylic resin component is formed. The planarizing film 284 is formed of a heat-resistant insulating resin such as acrylic or polyimide, and has surface irregularities caused by the TFT element 123 (driving element 4), the source electrode 243, the drain electrode 244, and the like. It is a well-known thing formed in order to eliminate.

  A pixel electrode 23 made of ITO or the like is formed on the surface of the planarizing film 284 and connected to the drain electrode 244 through a contact hole 23a provided in the planarizing film 284. That is, the pixel electrode 23 is connected to the high concentration drain region 241D of the silicon layer 241 through the drain electrode 244.

  On the surface of the planarizing film 284 on which the pixel electrode 23 is formed, the hole injection layer 70 and the light emitting layer 60 are laminated in this order from the pixel electrode 23 side, thereby forming a functional layer.

  The element substrate 2 having such an organic EL element 3 is bonded to a sealing substrate 13 made of glass or metal via a sealing resin. A getter agent 12 is attached to the sealed inner surface of the sealing substrate 13. The getter agent 12 absorbs moisture, oxygen, and the like that have entered the space 14 between the element substrate 2 and the sealing substrate 13, and prevents the organic EL element 3 from being deteriorated by the moisture, oxygen, or the like that has entered. is there. The getter agent 12 may be omitted.

  As shown in FIG. 4B, the top emission type organic EL element 3 is sequentially formed so as to cover the pixel electrode 24 (anode) as one electrode formed on the element substrate 2 and the pixel electrode 24. A stacked hole injection layer 70 and a light emitting layer 60, and a cathode (counter electrode) 51 as the other electrode formed so as to face the pixel electrode 24 through the hole injection layer 70 and the light emitting layer 60. I have.

  The pixel electrode 24 is connected to one of three terminals of the TFT element 123 as the driving element 4 formed on the element substrate 2. For example, Al is formed to a thickness of about 200 nm, and Ca is formed thereon. Are formed to have a thickness of about 20 nm and laminated, and Al also functions as a reflective layer. That is, it has a structure having a reflective layer corresponding to the pixel region.

  The cathode 51 is made of a transparent electrode material such as ITO (Indium Tin Oxide).

  When the organic EL element 3 is a top emission type, the light emitted from the light emitting layer 60 is reflected by the reflective layer of the pixel electrode 24 and extracted from the sealing substrate 13 side. A substrate or the like is used. The element substrate 2 can be either a transparent substrate or an opaque substrate. Examples of the opaque substrate include a thermosetting resin and a thermoplastic resin in addition to a ceramic sheet such as alumina and a metal sheet such as stainless steel that has been subjected to an insulation treatment such as surface oxidation.

  Since the circuit unit 11 for driving the top emission type organic EL element 3 is basically the same as the bottom emission type, the description thereof is omitted. The structure for sealing the element substrate 2 having the organic EL element 3 and the sealing substrate 13 is also the same.

  In both the bottom emission type and the top emission type, as a material for forming the hole injection layer 70, a dispersion liquid of 3,4-polyethylenediosithiophene / polystyrene sulfonic acid (PEDOT / PSS), that is, as a dispersion medium. A dispersion in which 3,4-polyethylenedioxythiophene is dispersed in polystyrene sulfonic acid and further dispersed in water is preferably used. The material for forming the hole injection layer 70 is not limited to the above, and various materials can be used. For example, those obtained by dispersing polystyrene, polypyrrole, polyaniline, polyacetylene or a derivative thereof in an appropriate dispersion medium such as polystyrene sulfonic acid can be used.

  Similarly, as a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence is used. In the present embodiment, for example, the light emitting layer 60 whose emission wavelength band corresponds to red is adopted, but of course, a light emitting layer whose emission wavelength band corresponds to green or blue may be adopted. In this case, the photoconductor used has sensitivity in the light emitting region.

  Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinyl carbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (PMPS) are preferably used. In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as.

  In this example, the TFT element 123 is formed on the element substrate 2 as the driving element 4 for driving the organic EL element 3. However, the driving element 4 is not formed on the element substrate 2 and is driven. Element 4 is externally attached. Specifically, the driver IC is COG mounted on the terminal area of the element substrate 2. Alternatively, a flexible circuit board on which a driver IC is mounted may be mounted on the element substrate 2.

(Line head manufacturing method)
Next, a method for manufacturing a line head as a light emitting device will be described with reference to FIGS. FIG. 5 is a flowchart showing a method for manufacturing a line head, and FIG. 6 is a schematic sectional view showing the method for manufacturing a line head. FIG. 6 shows a method of manufacturing a line head having a bottom emission type organic EL element. For convenience of illustration, the circuit portion 11 formed on the element substrate 2 is omitted.

  As shown in FIG. 5, in the method of manufacturing the line head 1 according to this embodiment, the step of forming the hole injection layer 70 on the entire surface of the element substrate 2 on which the pixel electrode 23 is formed (Step S1), and the formation The light emitting layer forming step (step S2) for laminating the light emitting layer 60 on the entire surface of the hole injection layer 70 formed, and the step of forming the cathode 50 having a reflective function so as to face the pixel electrode 23 (step S3). And. In addition, a deterioration process (step S4) is provided for deteriorating the light emitting layer 60 existing outside the region where the cathode 50 having a reflecting function is formed. Furthermore, the process (step S5) which joins the element substrate 2 in which the organic EL element 3 was formed, and the sealing substrate 13 is provided.

  Step S1 in FIG. 5 is a process for forming the hole injection layer 70. In step S1, as shown in FIG. 6A, the surface of the element substrate 2 on which the pixel electrode 23 is formed is dispersed using the method for forming the hole injection layer 70 using a method such as spin coating. A liquid is applied to form a film. Then, the process proceeds to step S2.

  Step S2 in FIG. 5 is a light emitting layer forming step. In step S2, as shown in FIG. 6B, a dispersion liquid containing the material for forming the light emitting layer 60 is applied to the surface of the formed hole injection layer 70 by using a method such as spin coating. To form a film. Alternatively, the material for forming the light emitting layer 60 described above may be used for vapor deposition in vacuum to form a film. Then, the process proceeds to step S3.

  Step S3 in FIG. 5 is a cathode forming step. In step S3, first, as shown in FIG. 6C, after depositing Ca to a thickness of about 20 nm by mask deposition, ITO is also deposited to form a transparent conductive film 50a in a desired pattern shape. Next, as shown in FIG. 6D, a reflective layer 50b is formed by depositing Al in a thickness of about 200 nm on the pixel region corresponding to the pixel electrode 23 by mask vapor deposition. A cathode 50 is formed by laminating these thin films.

  In this case, the reflective layer 50b may be any film thickness and material that does not transmit ultraviolet light or light including ultraviolet light, efficiently reflects light having a wavelength emitted by the light emitting layer 60, and has a work function. Can be selected as desired. Accordingly, it is possible to use a mixture of Ca, Sr, Al, Ag, Mg and the like as appropriate.

  In this case, the organic EL element 3 is formed such that the reflective layer 50b of the cathode 50 corresponding to the pixel electrode 23 is formed in a substantially circular shape so that the pixel region to emit light has a substantially circular shape. The shape of the reflective layer 50b is not limited to a substantially circular shape, and may be an ellipse or a quadrangle. Then, the process proceeds to step S4.

  Step S4 in FIG. 5 is a deterioration process. In step S4, as shown in FIG. 6E, for example, an ultraviolet ray having a wavelength of 380 nm or less from the opposite side (in the direction of the arrow) to the side of the cathode 50 having the reflecting function, that is, the cathode 50 having the reflecting layer 50b in contact with the light emitting layer 60. Irradiate light or light including ultraviolet light. As a result, the light emitting layer 60 made of an organic material existing in the region B other than the pixel region A, that is, the light emitting layer 60 not covered with the reflective layer 50b absorbs ultraviolet light and deteriorates. The amount of light irradiation is set so that the light emitting layer 60 absorbs ultraviolet light and deteriorates and deactivates. Therefore, it is preferable to appropriately set the irradiation amount depending on the material for forming the light emitting layer 60. Then, the process proceeds to step S5.

  Step S5 in FIG. 5 is a process of bonding the sealing substrate 13 to the element substrate 2. In step S5, as shown in FIG. 6F, the organic EL element 3 including a pixel electrode 23 as a pair of electrodes, a cathode 50, a hole injection layer 70 and a light emitting layer 60 stacked between these electrodes. The sealing substrate 13 is bonded to the element substrate 2 on which is formed via a sealing resin (not shown). As the sealing resin, an adhesive made of a thermosetting epoxy resin or the like can be used. As the sealing substrate 13, a substrate in which the getter agent 12 is attached in advance to the surface on the opposite element substrate 2 side is used. The getter agent 12 is not essential. For example, the space 14 with the element substrate 2 may be filled with a sealing resin. Furthermore, after the cathode 50 is formed, for example, silicon oxide, silicon nitride, or silicon oxynitride is formed on the entire surface as an inorganic sealing thin film to prevent deterioration of the organic EL element 3 due to moisture or oxygen entering the space 14. It is good also as a structure.

  The line head 1 as a light-emitting device manufactured in this way has a plurality of organic EL elements 3, and the light-emitting layer 60 that is not covered by the reflective layer 50b formed corresponding to the pixel region A has ultraviolet light. It absorbs and deteriorates. Therefore, even if a leak current flows between adjacent organic EL elements 3, it is possible to suppress unintended light emission in the light emitting layer 60 existing in the region B other than the pixel region A.

  6A to 6F show the manufacturing method of the bottom emission type light emitting device, but in the case of the top emission type of FIG. 4B, the element substrate 2 side in the deterioration process of step S4. The light emitting layer 60 existing in a region other than the region where the pixel electrode 24 having a reflective function is formed may be deteriorated by irradiating light from the light source.

  In addition, the method for degrading the light emitting layer 60 in the degradation process of step S4 is not limited to irradiation with ultraviolet light or light including ultraviolet light. For example, the light emitting layer 60 existing in the periphery of the pixel region may be deteriorated by irradiating laser light such as excimer, carbon dioxide, YAG or the like.

(Image forming device)
Next, an image forming apparatus provided with the line head module 101 of this embodiment will be described. FIG. 7 is a schematic view showing the structure of the image forming apparatus. In this image forming apparatus 80, the line head modules 101K, 101C, 101M, and 101Y according to the present invention are exposed to four photosensitive drums (image carriers) 41K, 41C, 41M, and 41Y having the same configuration. It is configured as a tandem system arranged in each device.

  The image forming apparatus 80 includes a driving roller 91, a driven roller 92, and a tension roller 93. The intermediate transfer belt 90 is stretched around these rollers so as to circulate and drive in the direction of the arrow (counterclockwise) in FIG. Is. Photosensitive drums 41K, 41C, 41M, and 41Y are arranged at predetermined intervals with respect to the intermediate transfer belt 90. These photoreceptor drums 41K, 41C, 41M, and 41Y have a photosensitive layer as an image carrier on the outer peripheral surface thereof.

Here, K, C, M, and Y in the above symbols mean black, cyan, magenta, and yellow, respectively, and indicate that the photoconductors are for black, cyan, magenta, and yellow, respectively.
The meanings of these symbols (K, C, M, Y) are the same for the other members. The photosensitive drums 41K, 41C, 41M, and 41Y are driven to rotate in the arrow direction (clockwise) in FIG. 7 in synchronization with the driving of the intermediate transfer belt 90.

  Around each photosensitive drum 41 (K, C, M, Y), charging means (corona charger) 42 for uniformly charging the outer peripheral surface of the photosensitive drum 41 (K, C, M, Y), respectively. (K, C, M, Y) and rotation of the photosensitive drum 41 (K, C, M, Y) on the outer peripheral surface uniformly charged by the charging means 42 (K, C, M, Y) And a line head module 101 (K, C, M, Y) that sequentially scans the line in synchronization with each other. Here, as described above, the line head module 101 (K, C, M, Y) is integrated by the head case 52 in a state in which the line head 1, the lens array 31, and the condenser lens 58 are aligned with each other. Is.

  Further, a developing device 44 (K, C, and C) that forms a visible image (toner image) by adding toner as a developer to the electrostatic latent image formed by the line head module 101 (K, C, M, and Y). M, Y) and a primary transfer roller 45 (K, C) as transfer means for sequentially transferring the toner image developed by the developing device 44 (K, C, M, Y) to the intermediate transfer belt 90 as a primary transfer target. , M, Y). In addition, a cleaning device 46 (K, C, M, Y) is provided as a cleaning unit for removing toner remaining on the surface of the photosensitive drum 41 (K, C, M, Y) after being transferred. Yes.

  In each line head module 101 (K, C, M, Y), the array direction of each line head 1 (the alignment direction of the organic EL elements 3) is on the rotation axis of the photosensitive drum 41 (K, C, M, Y). It is installed to be parallel. The emission energy peak wavelength of each line head module 101 (K, C, M, Y) and the sensitivity peak wavelength of the photosensitive drum 41 (K, C, M, Y) are set so as to substantially match. Yes.

  The developing device 44 (K, C, M, Y) uses, for example, nonmagnetic one-component toner as a developer. Then, the one-component developer is conveyed to the developing roller by, for example, a supply roller, the film thickness of the developer adhered to the surface of the developing roller is regulated by a regulating blade, and the developing roller is moved to the photosensitive drum 41 (K, C, M , Y) is brought into contact with or pressed against the photosensitive drum 41 (K, C, M, Y) to cause the developer to adhere and develop as a toner image.

  The black, cyan, magenta, and yellow toner images formed by the four-color single-color toner image forming station are intermediated by the primary transfer bias applied to the primary transfer roller 45 (K, C, M, Y). Primary transfer is sequentially performed on the transfer belt 90. The toner images that are sequentially superimposed on the intermediate transfer belt 90 to become a full color are secondarily transferred to the recording medium P such as paper by the secondary transfer roller 66 and further pass through the fixing roller pair 61 that is a fixing unit. Is fixed on the recording medium P. Thereafter, the paper is discharged onto a paper discharge tray 68 formed in the upper part of the apparatus by the paper discharge roller pair 62.

  In FIG. 7, reference numeral 63 denotes a paper feed cassette in which a large number of recording media P are stacked and held, 64 denotes a pickup roller for feeding the recording media P from the paper feed cassette 63 one by one, and 65 denotes secondary transfer. A pair of gate rollers for defining the supply timing of the recording medium P to the secondary transfer portion of the roller 66; a secondary transfer roller 66 as a secondary transfer means for forming a secondary transfer portion with the intermediate transfer belt 90; A cleaning blade 67 serves as a cleaning unit that removes toner remaining on the surface of the intermediate transfer belt 90 after the secondary transfer.

  In the image forming apparatus 80 shown in FIG. 7, the line head module 101 having the line head 1 shown in FIG. 2 is provided as an exposure unit. Therefore, since the so-called crosstalk in which the light emitting layer 60 existing in the region other than the pixel region emits light unintentionally due to the leakage current is reduced, a clear image with less blur after exposure can be obtained. The image forming apparatus 80 including the line head 1 of the present invention is not limited to the above-described embodiment, and various modifications can be made.

The effect of the said embodiment is as follows.
(1) The manufacturing method of the line head 1 of the said embodiment irradiates the light which contains ultraviolet light or ultraviolet light from the opposite side with respect to the side which contact | connects the light emitting layer 60 of the cathode 50 which has the reflection layer 50b, and a reflection layer A degradation process for degrading the light emitting layer 60 not covered with 50b is provided. The reflective layer 50 b is formed corresponding to the pixel region A of the pixel electrode 23. Therefore, even if a drive current is passed between the pixel electrode 23 and the cathode 50 and the light emitting layer 60 disposed therebetween emits light, even if a leak current flows between the adjacent organic EL elements 3, the pixel Since the light emitting layer 60 existing in the region B other than the region A is deteriorated, the line head 1 as a light emitting device in which unintended light emission hardly occurs can be manufactured. Moreover, if this manufacturing method is used, the line head 1 as a light-emitting device provided with the some organic EL element 3 with which it is hard to produce unintentional light emission by leak current can be provided.

  (2) In the method of manufacturing the line head 1 of the above embodiment, in the deterioration process, the side of the cathode 50 having the reflective layer 50b that is in contact with the light emitting layer 60 is irradiated with ultraviolet light or light containing ultraviolet light from the opposite side. Thus, the light emitting layer 60 not covered with the reflective layer 50b is deteriorated. Therefore, in the light emitting layer forming step (step S2), an evaporation mask is not required as compared with the case where the light emitting layer forming material is mask-deposited to form the light emitting layer 60 only at a desired position. Further, even when the arrangement of the organic EL elements 3 becomes high density, it is not necessary to align the vapor deposition mask with respect to the element substrate 2 with high accuracy, and the light emitting layer 60 existing in the region B other than the pixel region A is deteriorated. Can be made. That is, it is possible to manufacture a line head 1 in which unintended light emission due to a leak current hardly occurs even if the organic EL elements 3 are arranged at a high density.

  (3) In the method of manufacturing the line head 1 according to the above embodiment, in the deterioration process (step S4) for deteriorating the light emitting layer 60 as the organic light emitting layer, ultraviolet light or ultraviolet light is irradiated with an irradiation amount enough to deactivate the light emitting layer 60. Irradiate light including light. Therefore, the light emitting layer 60 can be deteriorated without irradiating excessive light, and unintentional light emission due to leakage current can be more efficiently suppressed.

  (4) The image forming apparatus 80 as the electronic apparatus of the above embodiment includes the line head module 101 having the line head 1 of the above embodiment as an exposure unit. Therefore, the photosensitive drum 41 can be exposed by unintentional light emission of the light emitting layer 60 due to leakage current, that is, light emission from the plurality of organic EL elements 3 in which crosstalk is reduced. That is, it is possible to provide an image forming apparatus 80 that can reduce defects such as bleeding due to crosstalk and obtain a clear image.

Modifications other than the above embodiment are as follows.
(Modification 1) In the method of manufacturing the line head 1 of the above embodiment, the method of deteriorating the light emitting layer 60 existing outside the region where the cathode 50 is formed is limited to the method of irradiating the light deteriorating the light emitting layer 60. Not. For example, if plasma treatment using oxygen as a processing gas is performed on the element substrate 2 on which the organic EL element 3 shown in FIG. 6E is formed, the light emitting layer 60 not covered with the cathode 50 may be deteriorated. it can.

  (Modification 2) In the method of manufacturing the line head 1 of the above embodiment, the method of forming the cathode 50 of the bottom emission type organic EL element 3 is not limited to this. For example, the reflective layer 50b may be formed on the entire pattern of the cathode 50 including the wiring portion connected to the power supply line. According to this, when light is irradiated in step S4 of the next process, the light emitting layer 60 existing outside the region where the cathode 50 is formed can be deteriorated. That is, it is possible to manufacture a line head 1 including a plurality of organic EL elements 3 in which the area of the light emitting layer 60 in which unintentional light emission occurs due to leakage current is reduced.

  (Modification 3) In the line head 1 of the above embodiment, the structure of the pixel electrode 24 of the top emission type organic EL element 3 is not limited to this. For example, the source electrode 243 or the drain electrode 244 can be expanded to be a pixel electrode having a reflection function. According to this, the line head 1 which has the organic EL element 3 of a simpler structure can be provided.

  (Modification 4) In the line head 1 of the above embodiment, the structure of the pixel electrode 24 having the reflection function of the top emission type organic EL element 3 is not limited to this. For example, the pixel electrode 24 may be formed of a transparent electrode material, and the reflective layer may be formed between the circuit unit 11 and the surface of the element substrate 2. According to this, the light emitting wavelength of the organic EL element 3 can be adjusted by the interference with the light emission of the light emitting layer 60 reflected by the reflective layer having a DHM (dielectric half miller) structure as an interlayer insulating film covering the silicon layer 241. That is, the color purity can be improved.

  (Modification 5) In the line head 1 of the above embodiment, the driving method for driving the organic EL element 3 is not limited to the active driving method using the TFT element 123 or the like. The method for manufacturing a light emitting device of the present invention can also be applied to a matrix driving type organic EL element 3 in which a so-called pixel electrode 23 and a cathode 50 are arranged in a lattice pattern and a light emitting layer 60 is disposed therebetween. is there.

  (Modification 6) The light emitting device manufactured using the method for manufacturing a light emitting device of the present invention is not limited to the line head 1. For example, the present invention can be applied to an illumination device, a display device, and the like provided with a plurality of single-color organic EL elements 3.

  (Modification 7) An electronic apparatus equipped with a light emitting device manufactured by using the method for manufacturing a light emitting device of the present invention is not limited to the image forming apparatus 80. For example, the present invention can also be applied to an information processing terminal device equipped with a display device including a plurality of single-color organic EL elements 3.

The perspective sectional view showing the structure of a line head module. The schematic diagram which shows the structure of a line head. The perspective view of a lens array. The schematic sectional drawing which shows the structure of an organic EL element and a drive element. The flowchart which shows the manufacturing method of a line head. The schematic sectional drawing which shows the manufacturing method of a line head. 1 is a schematic diagram illustrating a structure of an image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Line head as a light-emitting device, 2 ... Element board | substrate as a board | substrate, 3 ... Organic EL element as a light-emitting element, 23, 24 ... Pixel electrode as one electrode among a pair of electrodes, 50, 51 ... A pair of Of the electrodes, a cathode as the other electrode, 50b ... a reflective layer, 60 ... a light emitting layer as an organic light emitting layer, 80 ... an image forming apparatus as an electronic device, A ... a pixel region, B ... a region other than the pixel region.

Claims (8)

A method of manufacturing a light emitting device comprising a plurality of light emitting elements having a pair of electrodes and at least an organic light emitting layer disposed between the pair of electrodes,
A light emitting layer forming step of forming the organic light emitting layer on the entire surface on a substrate on which one of the pair of electrodes is formed;
Forming the other electrode on the formed organic light emitting layer so as to face the one electrode;
A method of manufacturing a light emitting device, comprising: a deterioration step of deteriorating the organic light emitting layer existing in a region other than one of the pair of electrodes. Either one of the pair of electrodes is formed to have a reflection function of reflecting light emitted from the organic light emitting layer,
In the deterioration step, the organic light emission which is not covered with the electrode having the reflection function by irradiating light from the opposite side to the side of the pair of electrodes having the reflection function that contacts the organic light emitting layer. The method for manufacturing a light emitting device according to claim 1, wherein the layer is deteriorated. Either one of the pair of electrodes is formed to have a reflective layer that does not transmit ultraviolet light or light including ultraviolet light,
The method for manufacturing a light emitting device according to claim 2, wherein in the deterioration step, ultraviolet light or light including ultraviolet light is irradiated.   The method for manufacturing a light-emitting device according to claim 3, wherein the reflective layer is formed on one of the pair of electrodes in a pixel region where the pair of electrodes are opposed to each other.   5. The method of manufacturing a light emitting device according to claim 2, wherein, in the deterioration step, the light is irradiated with an irradiation amount such that the organic light emitting layer is deactivated.   A light-emitting device comprising a plurality of light-emitting elements each having a pair of electrodes and at least an organic light-emitting layer disposed between the pair of electrodes, wherein the light-emitting device manufacturing method according to claim 1 is used. A light-emitting device manufactured.   6. A light-emitting device comprising a plurality of light-emitting elements each having a pair of electrodes each having a reflecting function and at least an organic light-emitting layer disposed between the pair of electrodes, A light-emitting device manufactured using the method for manufacturing a light-emitting device according to claim 1. An electronic apparatus comprising the light-emitting device according to claim 6.

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