JP2008288123A - LIGHT EMITTING DEVICE, IMAGE FORMING DEVICE, AND DISPLAY DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make formation of a light-emitting layer easy in a light-emitting device constituted by pinching the light-emitting layer of an organic membrane by an anode and a cathode. <P>SOLUTION: This is the light-emitting device constituted by pinching the light-emitting layer 10 of the organic membrane by a first electrode 20 to function as the anode and a second electrode 30 to function as the cathode. The first electrode 20 is formed to be a light-emitting unit, and a third electrode 40 of the same electrode as the second electrode 30 is mutually installed between the first electrodes 20, and the light-emitting layer 10 is continuously formed so as to cover the first electrode 20 and the third electrode 40. Moreover, an insulating material is installed between the first electrode 20 and the second electrode 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device, an image forming apparatus, and a display device configured by sandwiching a light emitting layer of an organic film between an anode and a cathode.

  In recent years, organic light emitting diodes (hereinafter referred to as “OLED elements”) elements called organic electroluminescence (organic EL) elements or light emitting polymer elements have attracted attention as next-generation light-emitting devices that replace liquid crystal elements. Has been. A panel using this OLED element is less dependent on the viewing angle because the OLED element is a self-luminous type, and is suitable for low power consumption and thinning because no backlight or reflected light is required. .

  FIG. 11 is a cross-sectional view illustrating an example of a light-emitting device using an OLED element. FIG. 11A illustrates a basic structure, and FIG. 11B illustrates a specific configuration. As shown in FIG. 11A, a light emitting device using an OLED element has a structure in which a light emitting layer 10 composed of an organic film is sandwiched between an anode 20 and a cathode 30 from both sides. In this structure, when a positive DC voltage is applied to the anode 20 and a negative DC voltage is applied to the cathode, an electric field as shown in the figure is generated in the light emitting layer 10, holes are injected from the anode 20, and travel toward the cathode 30. It is injected from the cathode 30 and proceeds toward the anode 20. Both are recombined in the light emitting layer 10 to be in an excited state, but since this state is unstable, it immediately returns to the ground state. The OLED element emits light by the energy released at this time.

A specific configuration of the light emitting device using the OLED element is as follows. That is, as shown in FIG. 11B, the anode 20 is formed on a transparent base material 60 such as glass through the wiring 25 and patterned in units of pixels (color pixels) that are light emission units. The anode 20 is generally made of transparent electrode ITO (Indium Tin Oxide). The light emitting layer 10 patterned in the same shape is formed on the anode 20, and the cathode 30 is formed so as to cover them. And the light-emitting device is comprised by sealing with the sealing material 70 (for example, patent document 1). Each light emitting layer 30 is electrically separated from other light emitting layers 30 by an insulating material 50. In this example, a single layer type using only a light emitting layer as an organic film is taken as an example for simplicity, but a multilayer type in which an electron transport layer, a hole transport layer, an electron injection layer, a hole injection layer, etc. are separately provided is used. There are many cases. In some cases, the light emitting layer also serves as an electron transporting layer.
JP 2003-7460 A (see FIG. 1)

  As described above, the anode 20 used as the pixel electrode is patterned on a pixel basis, and the light emitting layer 30 formed on the anode 20 is also formed by the same patterning. Insulated. Here, the pattern formation of the light emitting layer 30 is performed by vapor deposition using a mask or coating using inkjet.

  In recent years, light-emitting devices using OLED elements have been put into practical use as printer optical heads or display devices. In order to form a fine image with such a printer or display device, it is necessary to make the pixel pitch fine. When the pixel pitch is reduced, the light emitting layer 30 must be finely patterned. For this reason, the accuracy of the mask is required, or accurate color separation is required, resulting in a decrease in productivity and an increase in cost.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to facilitate the formation of a light emitting layer in a light emitting device configured by sandwiching a light emitting layer between an anode and a cathode.

  In order to solve the above-described problems, a light-emitting device according to the present invention includes a plurality of first electrodes, a single second electrode, and a light-emitting layer provided between the first electrode and the second electrode. A plurality of third electrodes provided between the first electrodes, to which a potential having the same polarity as the second electrode is supplied with reference to the potential of the first electrode; An insulating material provided between the third electrode and the first electrode, and the light emitting layer is continuously formed so as to cover the first electrode and the third electrode. And

  According to this invention, by providing the third electrode between the first electrodes, to which the potential of the same polarity as the second electrode is supplied when the potential of the first electrode is used as a reference, the light emitting layer is used as the light emitting unit. No need to form. For this reason, it becomes possible to form the light emitting units in a lump without coating them separately, and the light emitting layer can be easily formed. Note that the light emitting layer may be formed using, for example, an organic EL material, or may be formed using an inorganic EL material. The light emitting device supplies a fixed potential to the second electrode, supplies a potential corresponding to the gradation of the image to be displayed to the first electrode, and uses the potential of the first electrode as a reference for the third electrode. A drive circuit that supplies a potential having the same polarity as that of the second electrode may be provided.

  Specifically, the first electrode can be an anode, and the second and third electrodes can be cathodes. In this case, the third electrode is made of a material having a work function larger than that of the second electrode. It is desirable. This is because light emission between the first electrode and the third electrode can be prevented by reducing the electron injection efficiency of the third electrode.

On the other hand, when the first electrode is a cathode and the second electrode and the third electrode are anodes, it is desirable to use a material having a work function smaller than that of the second electrode. This is because light emission between the first electrode and the third electrode can be prevented by reducing the hole injection efficiency of the third electrode.
Furthermore, the second electrode and the third electrode can be at the same potential for easy voltage management. In order to prevent a short circuit, the first electrode and the third electrode are preferably electrically separated by the insulating material.

  Next, an image forming apparatus according to the present invention includes a photoconductor on which an image is formed by light irradiation, and a head unit that forms the image by irradiating the photoconductor with light. It is preferable to use the head portion. Next, the display device according to the present invention preferably includes the light emitting device described above.

  In order to solve the above-described problems, a method of manufacturing a light emitting device according to the present invention includes forming a plurality of first electrodes on a substrate by patterning light emitting units, and forming an auxiliary electrode between the first electrodes. And a step of continuously forming a light emitting layer so as to cover the first electrode and the auxiliary electrode, and a step of forming a second electrode on the light emitting layer. According to this invention, since the light emitting layer is continuously formed so as to cover the first electrode and the auxiliary electrode, the light emitting layer can be easily formed.

Embodiments of the present invention will be described below with reference to the drawings.
<Light emitting device>
FIG. 1 is a diagram showing a basic structure of a light emitting device according to an embodiment of the present invention. The same members as those in the “background art” described above are denoted by the same reference numerals. As shown in the figure, the light emitting device according to the present embodiment uses the anode 20 divided into pixel units as pixel electrodes, but the light emitting layer 10 is continuously formed without being patterned in pixel units. An auxiliary electrode 40 is provided between the anodes 20 to separate the displayed pixels. The cathode 30 is formed as a common electrode as usual.

  In this structure, when a positive DC voltage is applied to the anode 20, negative to the cathode 30, and negative voltage to the auxiliary electrode 40, an electric field as shown in the figure is generated, and holes are injected from the anode 20 and travel toward the cathode 30. Electrons are injected from the cathode 30 and travel toward the anode 20. Both are recombined in the light emitting layer 10 to be in an excited state, but since this state is unstable, it immediately returns to the ground state. The OLED element emits light by the energy released at this time. In the present embodiment, the light emitting layer 10 is continuous without being patterned in units of pixels. However, since the negative auxiliary electrode 40 is provided between the anodes 20, the light emitting layer 10 corresponding to the pixel has an anode. Since the recombination of the holes injected from 20 and the electrons injected from the cathode 30 does not occur, the light emission can be controlled on a pixel basis without coating the light emitting layer 10 separately.

  In the present embodiment, the negative voltage applied to the cathode 30 and the auxiliary electrode 40 is set to the same value, but both are applied in a range where no light emission occurs between the anodes 20 and between the auxiliary electrode 40 and the anode 20 in the light emitting layer 10. Different values may be used. Light emission between the auxiliary electrode 40 and the anode 20 in the light emitting layer 10 will be described later.

  FIG. 2 is a cross-sectional view showing a specific configuration of the light-emitting device according to the embodiment of the present invention. As shown in the drawing, the light emitting device is formed by patterning the anode 20 on a transparent base material 60 such as glass through the wiring 25 for each pixel. The anode 20 is generally made of transparent electrode ITO (Indium Tin Oxide). An auxiliary electrode 40 is formed between the adjacent anodes 20. The auxiliary electrode 40 is formed on the base material 60 via the wiring 45, and includes a transparent electrode ITO42 and an auxiliary electrode metal 41 for functioning as a cathode. Each anode 20 and auxiliary electrode 40 are electrically insulated by an insulating material 50. The light emitting layer 10 composed of an organic film is sandwiched between the anode 20, the auxiliary electrode 40 and the cathode 30 and sealed with a sealing material 70 to form a light emitting device. As described above, the light emitting layer 10 does not require patterning in units of pixels and can be formed continuously.

  FIG. 3 is a diagram illustrating an example when the anode 20 and the auxiliary electrode 40 are viewed from the light emitting layer 10 side. As shown in the drawing, the auxiliary electrode 40 is formed so as to surround the anode 20a and the anode 20b patterned in pixel units. However, the shapes of the anode 20 and the auxiliary electrode 40 are not limited to such shapes. Note that the light emitting layer 10 formed so as to cover them may use either a low molecular material or a high molecular material. In addition, the electrode driving method may be either a passive type or an active type.

  Next, materials used for the cathode 30 and the auxiliary electrode metal 41 will be described. In general, a material having a small work function is used for the cathode of the OLED. Typical materials having a small work function include magnesium, lithium, calcium, and the like. Here, magnesium is used for the cathode 30. Since the auxiliary electrode metal 41 is also used as a cathode, a material having a small work function is preferable. However, if the work function is too small, exchange of holes and electrons occurs between the anode 20 and the auxiliary electrode 40, and unnecessary light emission occurs in the light emitting layer 10. For this reason, a substance having a work function larger than that of the material of the cathode 30 is used. When magnesium is used as the cathode 30, for example, aluminum can be used as the auxiliary electrode metal 41.

  FIG. 4 is a diagram showing the energy levels of the light emitting layer 10, the anode 20, the cathode 30, and the auxiliary electrode 40. FIG. 4A shows the level before bonding. As shown in the figure, the light emitting layer 10 has a band structure of a conduction band and a valence band, and the energy level of ITO of the anode 20 and the energy level of magnesium of the cathode 30 are −4.6 eV, respectively. , −3.7 eV. The energy level of aluminum used as the auxiliary electrode metal 41 is lower than that of magnesium (that is, the work function is large) −4.3 eV.

  When the light emitting layer 10 and the electrode are joined, in the state where no voltage is applied, the energy levels are aligned and an electric field is generated in the light emitting layer 10 as shown in FIG. When a positive voltage is applied to the anode 20 and a negative voltage is applied to the cathode 30 and the auxiliary electrode 40, as shown in FIG. 4C, electrons are injected from the cathode 30 made of magnesium having a small work function, The holes injected from the anode 20 are recombined in the light emitting layer 10 to be in an excited state. Since this state is unstable, the state immediately returns to the ground state, and light is emitted from the light emitting layer 10 by the energy released at this time.

  In the present embodiment, the light emitting layer 10 is not patterned, but an auxiliary electrode 40 functioning as a cathode is provided around the anode 20. Since electrons and holes are not recombined in the auxiliary electrode 40 portion, light emission is performed only in the region of the light emitting layer 10 corresponding to the anode 20 patterned as a unit pixel.

  On the other hand, aluminum used as the auxiliary electrode metal 41 has a work function larger than that of the magnesium of the cathode 30, so that the injection of electrons into the light emitting layer 10 becomes low efficiency. For this reason, light emission between the auxiliary electrode 40 and the anode 20 can be avoided. As described above, according to the present embodiment, it is possible to emit light in units of pixels without patterning the light emitting layer.

  Next, with reference to FIG. 5 and FIG. 6, the manufacturing process of the light emitting part of the light emitting device according to this embodiment will be briefly described. FIG. 5A is a diagram in which the insulating material 50, the ITO of the anode 20, and the ITO 42 for the auxiliary electrode 40 are formed on the base material 60.

  As shown in FIG. 5B, a resist material is applied to the surface, and photolithography etching is performed so that the ITO 42 for the auxiliary electrode 40 is exposed, and the structure as shown in FIG. obtain. Next, as shown in FIG. 5D, by depositing aluminum on the surface and lifting off, the auxiliary electrode metal 41 can be formed as shown in FIG. 6A. The structure shown in FIG. 6B is obtained by evaporating or applying an EL material constituting the light emitting layer 10 on the surface. The deposition or application of the EL material can be continuously performed without patterning on a pixel basis. And the light emission part of a light-emitting device can be manufactured by vapor-depositing the magnesium used as the cathode 30. FIG.

In the above example, the anode is used as the pixel electrode. However, when the cathode is used as the pixel electrode, the auxiliary electrode also functions as the anode, and a material that is less likely to inject holes than the material used for the anode, That is, a material having a small work function is used as the auxiliary electrode metal. Also in this case, the light emitting layer can be continuously formed without patterning in units of pixels.
<Image forming apparatus>
The light emitting device according to the embodiment of the present invention can be used, for example, as an optical head of a printer as an image forming apparatus. FIG. 7 is a perspective view illustrating a partial configuration of an image forming apparatus to which the light emitting device according to the embodiment is applied. As shown in the figure, the image forming apparatus includes an optical head 100, a condensing lens array 150, and a photosensitive drum (image carrier) 110.

  The optical head 100 has a large number of light emitting elements arranged in an array. These light emitting elements selectively emit light according to an image to be printed on a recording material such as paper. In this example, since an OLED element is used as the light emitting element, the light emitting device according to this embodiment can be applied. The condensing lens array 150 is disposed between the optical head 100 and the photosensitive drum 110. The condensing lens array 150 includes a large number of gradient index lenses arranged in an array with each optical axis directed toward the optical head 100. The light emitted from each light emitting element of the optical head 100 passes through each gradient index lens of the condensing lens array 150 and forms an image on the surface of the photosensitive drum 110. The photosensitive drum 110 rotates, and a latent image corresponding to a desired image is formed at a predetermined exposure position on the surface of the photosensitive drum 110.

  FIG. 8 is a longitudinal side view showing an example of an image forming apparatus using the optical head 100 described above. This image forming apparatus includes four organic EL array exposure heads 100K, 100C, 100M, and 100Y having the same configuration and four corresponding photosensitive drums (image carriers) 110K, 110C, and 110M having the same configuration. , 110Y, respectively, and is configured as a tandem image forming apparatus. The organic EL array exposure heads 100K, 100C, 100M, and 100Y are configured by the optical head 100 described above.

  As shown in FIG. 8, the image forming apparatus includes a driving roller 121 and a driven roller 122, and includes an intermediate transfer belt 120 that is circulated and driven in the direction indicated by the arrow in the drawing. Photosensitive members 110K, 110C, 110M, and 110Y having photosensitive layers are arranged on the outer peripheral surface as four image carriers arranged at predetermined intervals with respect to the intermediate transfer belt 120. K, C, M, and Y added after the reference sign mean black, cyan, magenta, and yellow, respectively, and indicate that the photoconductors are black, cyan, magenta, and yellow, respectively. The same applies to other members. The photoreceptors 110K, 110C, 110M, and 110Y are rotationally driven in synchronization with the driving of the intermediate transfer belt 120.

  Around each photoconductor 110 (K, C, M, Y), charging means (corona charger) 111 (K) for uniformly charging the outer peripheral surface of the photoconductor 110 (K, C, M, Y), respectively. , C, M, Y) and the outer peripheral surface uniformly charged by the charging means 111 (K, C, M, Y) are synchronized with the rotation of the photoconductor 110 (K, C, M, Y). The organic EL array exposure head 100 (K, C, M, Y) as described above according to the present invention for sequentially scanning the lines is provided.

  Further, a developing device 114 (K) which applies toner as a developer to the electrostatic latent image formed by the organic EL array exposure head 100 (K, C, M, Y) to form a visible image (toner image). , C, M, Y).

  Here, in each organic EL array exposure head 100 (K, C, M, Y), the array direction of the organic EL array exposure head 100 (K, C, M, Y) is the photosensitive drum 110 (K, C, M). , Y) along the bus. Then, the emission energy peak wavelength of each organic EL array exposure head 100 (K, C, M, Y) and the sensitivity peak wavelength of the photoconductor 110 (K, C, M, Y) are set so as to substantially coincide. ing.

  The developing device 114 (K, C, M, Y) uses, for example, a non-magnetic one-component toner as a developer, and the one-component developer is conveyed to the developing roller by a supply roller, for example, and adhered to the developing roller surface. The film thickness of the developer is regulated by a regulation blade, and the developing roller is brought into contact with or increased in thickness by the photoreceptor 110 (K, C, M, Y). The toner image is developed by attaching a developer according to the potential level.

  The black, cyan, magenta, and yellow toner images formed by the four-color single-color toner image forming station are sequentially primary-transferred onto the intermediate transfer belt 120 and sequentially superimposed on the intermediate transfer belt 120 to form a full color. It becomes. The recording medium 102 fed one by one from the paper feed cassette 101 by the pickup roller 103 is sent to the secondary transfer roller 126. The toner image on the intermediate transfer belt 120 is secondarily transferred to the recording medium 102 such as a sheet by the secondary transfer roller 126 and is fixed on the recording medium 102 by passing through the fixing roller pair 127 as a fixing unit. Thereafter, the recording medium 102 is discharged onto a paper discharge tray formed in the upper part of the apparatus by a paper discharge roller pair 128.

  As described above, since the image forming apparatus of FIG. 8 uses the organic EL array as the writing means, the apparatus can be reduced in size as compared with the case where the laser scanning optical system is used.

  Next, another example of the image forming apparatus using the above-described optical head 100 will be described. FIG. 9 is a vertical side view of the image forming apparatus. In FIG. 9, the image forming apparatus includes, as main constituent members, a rotary developing device 161, a photosensitive drum 165 that functions as an image carrier, an exposure head 167 provided with an organic EL array, an intermediate transfer belt 169, and a sheet. A conveyance path 174, a fixing roller heating roller 172, and a paper feed tray 178 are provided. The exposure head 167 is configured by the optical head 100 described above.

  In the developing device 161, the developing rotary 161a rotates counterclockwise about the shaft 161b. The inside of the development rotary 161a is divided into four, and image forming units for four colors of yellow (Y), cyan (C), magenta (M), and black (K) are provided. The developing rollers 162a to 162d and the toner supply rollers 163a to 163 are respectively arranged in the image forming units for the four colors. Further, the toner is regulated to a predetermined thickness by the regulation flades 164a to 164d.

  The photosensitive drum 165 is charged by a charger 168 and is driven in a direction opposite to the developing roller 162a by a drive motor (not shown), for example, a step motor. The intermediate transfer belt 169 is stretched between the driven roller 170b and the drive roller 170a, and the drive roller 170a is connected to the drive motor of the photosensitive drum 165 to transmit power to the intermediate transfer belt. By driving the drive motor, the drive roller 170a of the intermediate transfer belt 169 is driven in the opposite direction to the photosensitive drum 165.

  The paper conveyance path 174 is provided with a plurality of conveyance rollers, a pair of paper discharge rollers 176, and the like, and conveys the paper. An image (toner image) on one side carried on the intermediate transfer belt 169 is transferred to one side of the paper at the position of the secondary transfer roller 171. The secondary transfer roller 171 is brought into contact with the intermediate transfer belt 169 by a clutch, and is brought into contact with the intermediate transfer belt 169 when the clutch is turned on to transfer an image onto a sheet.

  The sheet on which the image has been transferred as described above is then subjected to a fixing process by a fixing device having a fixing heater. The fixing device is provided with a heating roller 172 and a pressure roller 173. The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the arrow F direction. When the paper discharge roller pair 176 rotates in the opposite direction from this state, the paper reverses its direction and advances in the double-sided printing conveyance path 175 in the arrow G direction. The sheets are picked up one by one from the paper feed tray 178 by the pickup roller 179.

  For example, a low-speed brushless smoke is used as a drive motor for driving the conveyance roller in the sheet conveyance path. The intermediate transfer belt 169 uses a step motor because it requires color misregistration correction. Each of these motors is controlled by a signal from a control means (not shown).

  In the state shown in the drawing, a yellow (Y) electrostatic latent image is formed on the photosensitive drum 165, and a high voltage is applied to the developing roller 128a, whereby a yellow image is formed on the photosensitive drum 165. When all of the yellow back side and front side images are carried on the intermediate transfer belt 169, the development rotary 161a rotates 90 degrees.

  The intermediate transfer belt 169 rotates once and returns to the position of the photosensitive drum 165. Next, two images of cyan (C) are formed on the photosensitive drum 165, and this image is carried on the yellow image carried on the intermediate transfer belt 169. Thereafter, the 90-degree rotation of the development rotary 161 and the one-rotation process after the image is carried on the intermediate transfer belt 169 are repeated in the same manner.

For carrying four color images, the intermediate transfer belt 169 rotates four times, and then the rotation position is further controlled to transfer the image onto the sheet at the position of the secondary transfer roller 171. The sheet fed from the sheet feed tray 178 is conveyed by the conveyance path 174, and the color image is transferred to one side of the sheet at the position of the secondary transfer roller 171. The sheet on which the image is transferred on one side is reversed by the discharge roller pair 176 as described above, and stands by on the conveyance path. Thereafter, the sheet is conveyed to the position of the secondary transfer roller 171 at an appropriate timing, and the color image is transferred to the other side. The housing 180 is provided with an exhaust fan 181.
<Display device>
Next, a case where the above-described light emitting device is applied to a display device will be described. FIG. 10 is a block diagram illustrating a configuration of the display device. This display device includes a pixel area AA, a scanning line driving circuit 210, a data line driving circuit 220, a control circuit 230, and a power supply circuit 250. Among these, m scanning lines 201 are formed in the pixel area AA in parallel with the X direction. In addition, n data lines 203 are formed in parallel with the Y direction orthogonal to the X direction. A pixel circuit P is provided corresponding to each intersection of the scanning line 201 and the data line 203. Each pixel circuit 400 is supplied with the power supply voltage VDDEL via the power supply line 205. In this example, since the OLED is used as the light emitting element of the pixel circuit P, the above-described light emitting device can be applied.

  The scanning line driving circuit 210 generates scanning signals Y1, Y2, Y3,..., Ym for sequentially selecting a plurality of scanning lines 201. The scanning signals Y1 to Ym are generated by sequentially transferring the Y transfer start pulse DY in synchronization with the Y clock signal YCLK. The data line driving circuit 220 supplies gradation signals X1, X2, X3,..., Xn to each of the pixel circuits 400 located on the selected scanning line 201 based on the output gradation data Dout. In this example, the gradation signals X1 to Xn are given as voltage signals indicating gradation luminance.

  The control circuit 230 generates various control signals such as a Y clock signal YCLK, an X clock signal XCLK, an X transfer start pulse DY, and a Y transfer start pulse DY, and sends them to the scanning line driving circuit 210 and the data line driving circuit 220. Output. In addition, the control circuit 230 performs image processing such as gamma correction on the input gradation data Din supplied from the outside to generate output gradation data Dout.

  Electronic devices using display devices include mobile phones, personal computers, personal digital assistants, digital still cameras, television monitors, viewfinder type, monitor direct-view type video tape recorders, car navigation devices, pagers, and electronic notebooks. , Calculators, word processors, workstations, videophones, POS terminals, devices equipped with touch panels, and the like. And the display apparatus mentioned above is applicable as a display part of these various electronic devices.

It is a figure which shows the basic structure of the light-emitting device of this invention. It is sectional drawing which shows the specific structure of a light-emitting device. It is a figure which shows an example when an anode and an auxiliary electrode are seen from the light emitting layer side. It is a figure which shows the energy level of a light emitting layer, an anode, a cathode, and an auxiliary electrode. It is a figure explaining the manufacturing process of the light emission part of a light-emitting device. It is a figure explaining the manufacturing process of the light emission part of a light-emitting device. 1 is a perspective view illustrating a partial configuration of an image forming apparatus. It is a vertical side view which shows an example of an image forming apparatus. It is a vertical side view which shows the other example of an image forming apparatus. It is a block diagram which shows the structure of a display apparatus. It is sectional drawing which shows an example of the conventional light-emitting device using an OLED element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light emitting layer, 20 ... Anode, 25 ... Wiring, 30 ... Cathode, 30 ... Light emitting layer, 40 ... Auxiliary electrode. 41 ... Metal for auxiliary electrode, ITO ... 42, 45 ... Wiring, 50 ... Insulating material, 60 ... Base material, 70 ... Sealing material, 100 ... Optical head

Claims (8)

A light emitting device comprising a plurality of first electrodes, a single second electrode, and a light emitting layer provided between the first electrode and the second electrode,
A plurality of third electrodes provided between the first electrodes, to which a potential having the same polarity as the second electrode is supplied with reference to the potential of the first electrode;
An insulating material provided between the third electrode and the first electrode;
The light emitting layer is continuously formed so as to cover the first electrode and the third electrode.
A light emitting device characterized by that. The first electrode is an anode, the second electrode and the third electrode are cathodes;
The third electrode uses a material having a work function larger than that of the second electrode.
The light-emitting device according to claim 1. The first electrode is a cathode, the second electrode and the third electrode are anodes;
The third electrode uses a material having a work function smaller than that of the second electrode.
The light-emitting device according to claim 1.   4. The light emitting device according to claim 1, wherein the second electrode and the third electrode have the same potential. 5.   4. The light emitting device according to claim 1, wherein the first electrode and the third electrode are electrically separated by the insulating material. 5. A photoreceptor on which an image is formed by light irradiation;
A head unit for irradiating the photosensitive member with light to form the image;
An image forming apparatus using the light emitting device according to claim 1 for the head portion.   A display device comprising the light-emitting device according to claim 1. Forming a plurality of first electrodes on the substrate by patterning the light emitting units, and forming an auxiliary electrode between the first electrodes;
Continuously forming a light emitting layer so as to cover the first electrode and the auxiliary electrode;
And a step of forming a second electrode on the light emitting layer.

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