JP5157790B2 - Image forming apparatus and manufacturing method thereof - Google Patents

Description

  The present invention relates to an image forming apparatus using an organic EL (electroluminescence) element and a manufacturing method thereof.

  The organic EL element includes, for example, an anode electrode, a cathode electrode, and a plurality of carrier transport layers such as an electron injection layer, a light emitting layer, and a hole injection layer formed between these electrodes. In the organic EL element, light is emitted by energy generated by recombination of holes supplied from the hole injection layer and electrons supplied from the electron injection layer in the light emitting layer. Such an organic EL element is used as a display device as disclosed in Patent Document 1, and is driven by, for example, a TFT (Thin Film Transistor) provided in each pixel.

JP 2001-195012 A

  Incidentally, a light emitting device having an organic EL element is also used as an image forming apparatus. In order to extend the life of the organic EL element, it is important to remove heat generated when the organic EL element is driven. Furthermore, when temperature irregularity occurs in the light emitter substrate, there is a high possibility that luminance irregularity due to the temperature irregularity is likely to occur.

  In addition, when the organic EL element deteriorates as the temperature rises and the light emission luminance decreases, the exposure time must be increased in order to obtain the amount of light necessary for the photosensitive body or photosensitive material of the printing apparatus, and as a result There is a problem that the printing speed becomes slow.

  As described above, there is a demand for an image forming apparatus capable of satisfactorily removing heat generated in an organic EL element and a method for manufacturing the same.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an image forming apparatus capable of removing heat generated in an organic EL element satisfactorily and a manufacturing method thereof.

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention includes:
A luminescent pixel;
A light emitting pixel substrate formed with a groove having a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove ;
A sealing substrate for sealing the first groove portion of the light emitting pixel substrate;
A volatile liquid enclosed in the groove,
Furthermore, the heat transfer plate disposed so as to contact the sealing substrate at a position facing the second groove portion of the light emitting pixel substrate, or the light emitting pixel substrate facing the second groove portion of the light emitting pixel substrate. One of the heat transfer plates made of a metal plate arranged to contact,
A light emitting part having a heat radiating plate in contact with the surface opposite to the surface facing the second groove of the heat transfer plate ,
The heat transfer plate, and characterized that you transfer heat from the gas to move the volatile liquid is vaporized in the second groove in said first groove portion by the heat emitted from the light emitting pixels on the heat radiating plate To do.

  The sealing substrate and the light emitting pixel substrate may be bonded by an adhesive member.

  A metal film may be formed on a surface of the groove formed on the light emitting pixel substrate.

  A recess may be formed in the sealing substrate in a region facing the light emitting pixel.

In order to achieve the above object, an image forming apparatus manufacturing method according to a second aspect of the present invention includes:
Forming a light-emitting pixel light emission pixels on a substrate,
On the surface of the light emitting pixel substrate facing the sealing substrate, a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove. Forming a groove having ,
Sealing the groove of the light emitting pixel substrate and the sealing substrate;
A step of encapsulating the volatile liquid in the groove,
Disposing a heat transfer plate in contact with the sealing substrate at a position facing the second groove of the light emitting pixel substrate;
And a step of contacting a heat radiating plate to a surface opposite to the surface facing the second groove of the heat transfer plate .
And another method of manufacturing the image forming apparatus of the present invention is as follows.
Forming a light emitting pixel on the light emitting pixel substrate;
On the surface of the light emitting pixel substrate facing the sealing substrate, a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove. Forming a groove having,
Sealing the first groove portion of the light emitting pixel substrate and the sealing substrate, and sealing the second groove portion of the light emitting pixel substrate and a heat transfer plate made of a metal plate;
Enclosing a volatile liquid in the groove;
And a step of contacting a heat radiating plate to a surface opposite to the surface facing the second groove of the heat transfer plate.

  ADVANTAGE OF THE INVENTION According to this invention, the image forming apparatus which can remove favorably the heat which arises in an organic EL element by forming the groove | channel which functions as a cooling tube in a light emitting pixel substrate can be provided, and its manufacturing method. .

  An image forming apparatus and an image forming apparatus manufacturing method according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an image forming apparatus using a bottom emission type organic EL (electroluminescence) element as a light emitting unit will be described as an example.

(First embodiment)
An image forming apparatus and a method for manufacturing the image forming apparatus according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of an image forming apparatus 10 according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of the light emitting unit 20 of the image forming apparatus. 3 is a plan view showing the light-emitting panel 21, and FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. FIG. 5 is an equivalent circuit diagram showing a driving circuit for the light emitting pixels of the light emitting panel 21. 6 is a plan view of the luminescent pixel, and FIG. 7 is a cross-sectional view of the luminescent pixel taken along line VII-VII.

  The image forming apparatus 10 includes a drum-shaped photoconductor 11 that forms a latent image with a light emitting unit 20, a charging unit 12 that charges the photoconductor, a light emitting unit 20, and a developing unit 13 that forms a toner image on the photoconductor. The image forming apparatus includes a transfer unit 14 that transfers a toner image formed on the photosensitive member to transfer paper, a fixing device 16, a cleaner 17, and a static eliminator 18. In the image forming apparatus 10 of the present embodiment, charging, exposure, development, and transfer are performed, and a desired image is formed on the transfer paper 19.

The charging unit 12 charges the photoconductor 11.
The light emitting unit 20 causes the light emitting pixels in the light emitting unit to emit light with a light emission pattern corresponding to the image to be formed, and exposes the photoconductor 11. Thereby, an electrostatic latent image is formed on the photoreceptor 11.

  The developing unit 13 supplies toner onto the photoreceptor 11. On the photoconductor 11, toner is attracted to the photoconductor 11 in accordance with the electrostatic latent image, thereby forming a toner image corresponding to the electrostatic latent image.

The transfer unit 14 transfers the toner image formed on the photoconductor to the transfer paper 19.
The fixing device 16 is a device that heats the transfer paper 19, and the toner on the transfer paper 19 is fixed to the paper by applying heat. The transfer paper 19 is conveyed by a transfer paper conveyance unit (not shown).

The cleaner 17 transfers the toner on the photoconductor 11 to the transfer paper 19 and then removes the toner remaining on the photoconductor 11.
The static eliminator 18 neutralizes the surface of the photoreceptor 11 for the next charging.

  As shown in FIG. 2, the light emitting unit 20 of the present embodiment includes a light emitting panel 21, a housing 22 that holds the light emitting panel, a heat radiating plate 23, a heat transfer plate 24, and a rod lens 25.

  The housing 22 is formed of a light-shielding material, and includes a recess 22a where the light emitting panel 21 is installed, a recess 22b where the rod lens 25 is installed, and a recess 22c where the heat sink 23 is installed. The light emitting panel 21, the rod lens 25, and the heat sink 23 are held. The rod lens 25 is installed at a portion facing the photoconductor 11, and guides light emitted from each light emitting pixel of the light emitting unit 20 to the photoconductor 11.

  The heat radiating plate 23 is made of a material having high thermal conductivity, such as aluminum or stainless steel. The heat radiating plate 23 is installed on the side of the light emitting panel 21 that faces the light extraction surface. The heat emitted from the light emitting panel 21 is dissipated through the heat transfer plate 24 provided therebetween. The heat transfer plate 24 is also formed of a material having high thermal conductivity, such as aluminum or stainless steel.

  3 and 4, the light-emitting panel 21 includes a light-emitting pixel substrate 31, a light-emitting pixel 30, a sealing substrate 32 disposed opposite to the light-emitting pixel substrate 31, a thin tube 33, and a working liquid injection port. 34, an inlet sealing portion 35, and a working fluid 36.

  The light emitting pixel substrate 31 is formed of a light transmitting substrate, for example, a glass substrate. On the light emitting pixel substrate 31, a light emitting pixel array in which the light emitting pixels 30 made of the organic EL elements OLED are arranged in a line is formed. Each light emitting pixel 30 is provided with a wiring (not shown) connected to the light emitting pixel 30 and further connected to a drive unit (not shown) made of an IC chip or the like. Light emitted from the light emitting pixels 30 is extracted from the light emitting pixel substrate 31 side and guided to the photoconductor 11 through the rod lens 25. A groove 31 a is formed on the surface of the light emitting pixel substrate 31 that faces the sealing substrate 32. As shown in FIG. 3, the groove 31 a is formed to meander in a region adjacent to the light emitting pixel array, and is formed in a straight line in a region near the heat transfer plate 24. The light emitting pixel substrate 31 and the sealing substrate 32 are sealed with a sealing agent made of, for example, an ultraviolet curable resin or a thermosetting resin.

  A metal film 33a is formed on the surface of the groove 31a. The metal film 33a may be formed only on the surface of the groove 31a, or may be formed on the light emitting pixel substrate 31 around the groove 31a. As will be described in detail later, the metal film 33 a is formed at the same time in the step of forming the counter electrode 46 of the light emitting pixel 30 on the light emitting pixel substrate 31. Further, as will be described later, the counter electrode 46 is an electrode common to the plurality of light emitting pixels 30 and is connected to a common potential (for example, ground potential). Therefore, the metal film 33a and the counter electrode 46 are integrally formed. May be. Thus, by forming the counter electrode 46 and the metal film 33a integrally, it is possible to further increase the thermal conductivity from the light emitting pixel 30. In the present embodiment, the counter electrode 46 has a laminated structure including a layer made of a material having a low work function such as Li, Mg, Ca, Ba, and a light-reflective conductive layer such as Al. It is a single layer structure of only Al.

  In the present embodiment, a groove 31 a is formed in the light emitting pixel substrate 31, and sealing is performed on the opposing surface of the light emitting pixel substrate 31 and the sealing substrate 32 excluding the recess 32 a of the sealing substrate 32 and the groove 31 a of the light emitting pixel substrate 31. The groove 31a functions as a thin tube 33 (cooling tube) by sealing with the intervening stop agent. The thin tube 33 includes a thin tube 33b that is disposed on the light emitting pixel 30 side and has a relatively large surface area by meandering, and a thin tube 33c that is disposed on the outer side of the light emitting panel 21 and is connected to the thin tube 33b. . This thin tube 33 is partially filled with a liquid (working fluid) 36 that is easily vaporized under reduced pressure, such as water or alcohol. Thereby, the thin tube 33 functions as a heat pipe. As shown in FIG. 3, the thin tube 33 b is adjacent to the light emitting pixel 30 and is heated by heat generated from the light emitting pixel 30. Heat is dissipated from the heat radiating plate 23 through the heat transfer plate 24 to the thin tube 33c. Thereby, the thin tube 33c can be cooled. In this way, a part of the working fluid 36 is vaporized in the thin tube 33b on the light emitting pixel side by the heat from the light emitting pixel 30, and the heated gas moves to the thin tube 33c to release the heat of vaporization on the heat transfer plate side. To do. At this time, the vaporized vapor becomes a low temperature due to heat radiation, liquefies on the heat transfer plate side, becomes the working liquid 36, and moves again to the narrow tube 33b. By repeating this heat absorption and heat dissipation, heat can be moved to the heat sink, heat generated from the pixels can be moved to the heat sink, and the pixels can be cooled. In addition, since heat is transferred by the thin tubes 33, temperature unevenness in the arrangement direction of the light emitting pixels 30 can be reduced. Note that the working fluid is injected from the working fluid inlet 34 after sealing the sealing substrate 32 and the light emitting pixel substrate 31 as will be described in detail later. The hydraulic fluid injection port 34 is sealed by the injection port sealing part 35. The thin tubes 33 are formed in a continuous manner so that there are two paths between the thin tube 33 b on the light emitting pixel side and the thin tube 33 c on the heat transfer plate side. For this reason, the vapor of the working liquid 36 moves from the thin tube 33b on the light emitting pixel side to the thin tube 33c on the heat transfer plate side in one path, and the working liquid 36 flows from the thin tube 33c on the heat transfer plate side by the vapor pressure in the other path. By moving to the thin tube 33b on the light emitting pixel side, the working liquid 36 can flow efficiently.

  The sealing substrate 32 is a substrate made of glass, metal, plastic, or the like, and is installed so as to face the light emitting pixel substrate 31. A depression 32 a corresponding to the light emitting pixel 30 is formed on the surface of the sealing substrate 32 facing the light emitting pixel substrate 31. The light emitting pixel substrate 31 and the sealing substrate 32 are sealed with a sealing agent made of, for example, an ultraviolet curable resin or a thermosetting resin. A space formed by the recess 32a of the sealing substrate 32 and the light emitting pixel substrate 31 is filled with an inert gas, silicon oil, or the like. In addition, the sealing substrate 32 may be sealed by applying a sheet-like adhesive, a high-viscosity adhesive, or the like on the light emitting pixels 30 without providing the depressions 32 a corresponding to the light emitting pixels 30. (Solid sealing). In this case, since the step of the light emitting pixel 30 is absorbed by the thickness of the adhesive, the light emitting pixel 30 is hardly affected.

  The light emitting pixels 30 are formed on a light emitting pixel substrate 31 as shown in FIG. 4, and each light emitting pixel 30 includes an organic EL element OLED and a light emitting pixel circuit DS that actively operates the organic EL element.

  As shown in FIG. 5, the light emitting pixel circuit DS includes a selection transistor Tr11, a light emission drive transistor Tr12, a capacitor Cs, and an organic EL element OLED. Each of the selection transistor Tr11 and the light emission drive transistor Tr12 is an inverted staggered n-channel TFT (Thin Film Transistor) including a semiconductor layer having amorphous silicon.

  On the luminescent pixel substrate 31, anode lines La connected to the plurality of luminescent pixel circuits DS arranged in the row direction and a plurality of data lines respectively connected to the plurality of luminescent pixel circuits DS arranged in the row direction. Ld and a gate line Lg for selecting the transistors Tr11 of the plurality of light emitting pixel circuits DS arranged in the row direction are formed.

  As shown in FIG. 5, the selection transistor Tr11 has a gate terminal connected to the gate line Lg, a drain terminal connected to the data line Ld, and a source terminal connected to the contact N11. The light emission driving transistor Tr12 has a gate terminal connected to the contact N11, a drain terminal connected to the anode line La, and a source terminal connected to the contact N12. The capacitor Cs is connected to the gate terminal and the source terminal of the light emission drive transistor Tr12. Note that the capacitor Cs is an auxiliary capacitance additionally provided between the gate and the source of the light emission driving transistor Tr12 or a capacitance component including a parasitic capacitance and an auxiliary capacitance between the gate and the source of the light emission driving transistor Tr12. In the organic EL element OLED, the anode terminal (pixel electrode 42) is connected to the contact N12, and the reference voltage Vss is applied to the cathode terminal (counter electrode 46).

  The gate line Lg is connected to a scanning driver (not shown) arranged at the peripheral edge of the light emitting panel, and is a selection for setting a plurality of light emitting pixels 30 arranged in the row direction at a predetermined timing to a selected state. A voltage signal (scanning signal) is applied. The data line Ld is connected to a data driver (not shown) arranged at the peripheral edge of the light emitting panel, and a data voltage (grayscale signal) corresponding to the light emission data at a timing synchronized with the selection state of the light emitting pixel 30. ) Is applied. The plurality of light emission drive transistors Tr12 arranged in the row direction are set to a state in which a light emission drive current corresponding to the light emission data flows through the pixel electrode (for example, anode electrode) of the organic EL element OLED connected to the light emission drive transistor Tr12. As described above, the anode line La (supply voltage line) is directly or indirectly connected to a predetermined high potential power source. That is, a predetermined high potential (supply voltage Vdd) that is sufficiently higher than the reference voltage Vss applied to the counter electrode 46 of the organic EL element is applied to the anode line La. Further, the counter electrode 46 is connected directly or indirectly to a predetermined low potential power source, for example, and is a single unit for all the light emitting pixels (organic EL elements) arranged in an array on the light emitting pixel substrate 31. It is formed of an electrode layer, and is set so that a predetermined low voltage (reference voltage Vss, for example, ground potential GND) is applied in common.

  The insulating film 41 is made of an insulating material such as a silicon oxide film or a silicon nitride film, and is formed on the light emitting pixel substrate 31 so as to cover the data line Ld, the gate electrode Tr11g, and the gate electrode Tr12g.

  The anode line La and the gate line Lg are formed together with the source electrode and the drain electrode using a source-drain conductive layer that forms the source electrode and the drain electrode of each of the transistors Tr11 and Tr12. The data line Ld is formed together with the gate electrode using a gate conductive layer that becomes a gate electrode of each of the transistors Tr11 and Tr12. A contact hole 61 is formed in the insulating film 41 between the data line Ld and the drain electrode Tr11d, and the data line Ld and the drain electrode Tr11d are electrically connected via the contact hole 61. Contact holes 62 and 63 are formed in the insulating film 41 between the gate line Lg and both ends of the gate electrode Tr11g, respectively. The gate line Lg and the gate electrode Tr11g are electrically connected via the contact holes 62 and 63. . A contact hole 64 is formed in the insulating film 41 between the source electrode Tr11s and the gate electrode Tr12g, and the source electrode Tr11s and the gate electrode Tr12g are electrically connected via the contact hole 64.

  Next, the organic EL element OLED includes a pixel electrode 42, a hole injection layer 43, an interlayer 44, a light emitting layer 45, and a counter electrode 46. The hole injection layer 43, the interlayer 44, and the light emitting layer 45 serve as a carrier transport layer in which electrons and holes are transported as carriers. The carrier transport layer is disposed between the interlayer insulating film 47 and the partition wall 48 arranged in the column direction.

  On the light emitting pixel substrate 31 of each light emitting pixel, a selection transistor Tr11 formed by patterning a gate conductive layer and gate electrodes Tr11g and Tr12g of the light emission driving transistor Tr12 are formed. On the light emitting pixel substrate 31 adjacent to each light emitting pixel, a data line Ld extending in the column direction is formed by patterning a gate conductive layer.

  Each of the selection transistor Tr11 and the light emission drive transistor Tr12 is an n-channel thin film transistor (TFT). Each transistor is formed on the light emitting pixel substrate 31. As shown in FIG. 7, the light emission drive transistor Tr12 includes an insulating film 41, a semiconductor layer 121, a protective insulating film 122, a drain electrode Tr12d, a source electrode Tr12s, ohmic contact layers 123 and 124, and a gate electrode Tr12g. And comprising. Similarly to the light emission drive transistor Tr12, the selection transistor Tr11 also includes an insulating film 41, a semiconductor layer (not shown), a protective insulating film (not shown), a drain electrode Tr11d, a source electrode Tr11s, and an ohmic contact. A contact layer (not shown) and a gate electrode Tr11g are provided.

  In each of the transistors Tr11 and Tr12, the gate electrode is an opaque gate conductive layer made of, for example, a Mo film, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film or an AlNdTi alloy film, a MoNb alloy film, or the like. It is formed. The drain electrode and the source electrode are each formed of a source-drain conductive layer such as aluminum-titanium (AlTi) / Cr, AlNdTi / Cr, or Cr. In addition, an ohmic contact layer is formed between the drain electrode and the source electrode and the semiconductor layer for low resistance contact.

  The pixel electrode (anode electrode) 42 is made of a conductive material having translucency, for example, ITO (Indium Tin Oxide), ZnO, or the like. Each pixel electrode 42 is insulated from the pixel electrode 42 of another adjacent light emitting pixel 30 by an interlayer insulating film 47.

  The interlayer insulating film 47 is formed of an insulating material such as a silicon nitride film, and is formed between the pixel electrodes 42 to insulate and protect the transistors Tr11 and Tr12, the gate line Lg, and the anode line La. A substantially rectangular opening 47a is formed in the interlayer insulating film 47, and a light emitting region of the light emitting pixel 30 is defined by the opening 47a. Further, a groove-like opening 48 a extending in the column direction (vertical direction in FIG. 6) is formed in the partition wall 48 over the plurality of light emitting pixels 30 on the interlayer insulating film 47.

  The partition wall 48 is formed by curing an insulating material, for example, a photosensitive resin such as polyimide, and is formed on the interlayer insulating film 47. As shown in FIG. 6, the partition wall 48 is formed in a stripe shape so as to collectively open the light emitting pixel electrodes 42 of a plurality of light emitting pixels along the column direction. The planar shape of the partition wall 48 is not limited to this, and may be a lattice shape having an opening for each light emitting pixel electrode 42.

  The hole injection layer 43 is formed on the light emitting pixel electrode 42 and has a function of supplying holes to the light emitting layer 45. The hole injection layer 43 is made of an organic polymer material that can inject and transport holes. As an organic compound-containing liquid containing an organic polymer hole injection / transport material, for example, polyethylenedioxythiophene (PEDOT) which is a conductive polymer and polystyrene sulfonic acid (PSS) which is a dopant are dispersed in an aqueous solvent. A PEDOT / PSS aqueous solution that is a dispersion is used.

  The interlayer 44 is formed on the hole injection layer 43. The inter-layer 44 has a function of suppressing the hole injection property of the hole injection layer 43 and facilitating recombination of electrons and holes in the light emitting layer 45, in order to increase the light emission efficiency of the light emitting layer 45. Is provided.

  The light emitting layer 45 is formed on the interlayer 44. The light emitting layer 45 has a function of generating light by applying a voltage between the anode electrode and the cathode electrode. The light emitting layer 45 is made of a known polymer light emitting material capable of emitting fluorescence or phosphorescence, for example, a light emitting material containing a conjugated double bond polymer such as polyparaphenylene vinylene or polyfluorene. In addition, these luminescent materials are appropriately coated with a solution (dispersion) dissolved (or dispersed) in an aqueous solvent or an organic solvent such as tetralin, tetramethylbenzene, mesitylene, and xylene by a nozzle coating method, an inkjet method, or the like. It is formed by volatilizing.

  Further, in the case of the bottom emission type, the counter electrode (cathode electrode) 46 is provided on the light emitting layer 45 side, and is an electron injecting lower layer made of a conductive material, for example, a material having a low work function such as Li, Mg, Ca, Ba or the like. And a laminated structure having an upper layer made of a light-reflective conductive metal such as Al. In the case of a top emission type, it is provided on the light emitting layer 45 side and is extremely thin with a thickness of about 10 nm, for example, Li, Mg, Ca, Ba A transparent laminated structure having a light transmissive low work function layer made of a material having a low work function such as ITO and a light reflective conductive layer such as ITO having a thickness of about 100 nm to 200 nm. In the present embodiment, the counter electrode 46 is composed of a single electrode layer formed across the plurality of light emitting pixels 30 and is applied with a common voltage Vss, which is a ground potential, for example. In the present embodiment, as will be described in detail later, the metal film 33a formed on the surface of the groove 31a of the light emitting pixel substrate 31 and the counter electrode 46 are manufactured in the same process.

  As described above, the image forming apparatus 10 according to this embodiment forms the thin tubes 33 that function as heat pipes on the light emitting panel 21 of the light emitting unit 20, thereby favorably generating heat generated from the light emitting pixels 30. The heat generated in the light emitting pixel 30 can be removed, and the occurrence of temperature unevenness in the light emitting pixel 30 can be suppressed. Thereby, it is possible to suppress the occurrence of luminance unevenness due to the long life of the organic EL element of the light emitting pixel 30 and the temperature unevenness.

  Next, a method for manufacturing the image forming apparatus according to the present embodiment will be described with reference to FIGS. Here, since the selection transistor Tr11 is formed by the same process as the light emission drive transistor Tr12, a part of the description of the formation of the selection transistor Tr11 is omitted.

  First, as shown in FIG. 8A, a recess portion is formed on the surface of the sealing substrate 32 made of, for example, a glass substrate facing the light emitting pixel substrate 31 by physical polishing or chemical polishing such as sandblasting, photolithography, etching, or the like. 32a is formed. In addition, when sealing by apply | coating a sheet-like adhesive agent, a highly viscous adhesive agent, etc. also on the light emitting pixel 30, this process can be abbreviate | omitted.

  Next, as shown in FIG. 8B, a light emitting pixel substrate 31 made of a glass substrate or the like is prepared. A groove 31a is formed on the surface of the light emitting pixel substrate 31 facing the sealing substrate 32 by physical polishing or chemical polishing such as sand blasting, photolithography, or etching. At this time, the hydraulic fluid inlet 34 is also formed at the same time.

  Next, the light emitting pixel substrate 31 is made of, for example, a Mo film, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, an AlNdTi alloy film, a MoNb alloy film, or the like by sputtering, vacuum deposition, or the like. A gate conductive film is formed and patterned into the shapes of the gate electrodes of the transistors Tr11 and Tr12 and the data line Ld as shown in FIG. Subsequently, as shown in FIG. 8D, an insulating film 41 is formed on the gate electrode Tr12g and the data line Ld by a CVD (Chemical Vapor Deposition) method or the like.

  Next, an amorphous silicon layer and a silicon nitride layer are deposited on the insulating film 41 by a CVD method or the like, and the protective nitride film 122 is formed by patterning the silicon nitride layer by photolithography. Next, after depositing an amorphous silicon layer containing an n-type impurity, the ohmic contact layers 123 and 124 and the semiconductor layer 121 are formed by etching together with the lower amorphous silicon layer by photolithography.

  Next, a transparent conductive film such as ITO or a light-reflective conductive film and a transparent conductive film such as ITO are coated on the insulating film 41 by sputtering, vacuum vapor deposition, or the like, and then patterned by photolithography to form the pixel electrode 42. Form.

  Subsequently, after forming contact holes 61 to 64 as through holes in the insulating film 41, for example, a Mo film, a Cr film, an Al film, a Cr / Al laminated film, an AlTi alloy film, an AlNdTi alloy film, or a MoNb alloy film. A source-drain conductive film made of, for example, is coated by sputtering, vacuum deposition or the like, and patterned by photolithography to form the drain electrode Tr12d, source electrode Tr12s, and anode line La as shown in FIGS. Form. At this time, the source electrode Tr12s of the light emission drive transistor Tr12 is formed so as to overlap with a part of the pixel electrode 42, respectively.

  Subsequently, as shown in FIG. 9A, an interlayer insulating film 47 made of a silicon nitride film is formed by CVD or the like so as to cover the transistor Tr12 and the like, and then an opening 47a is formed by photolithography. Next, photosensitive polyimide is applied so as to cover the interlayer insulating film 47, and is patterned by exposure and development through a mask corresponding to the shape of the partition wall 48, and as shown in FIG. A partition wall 48 is formed.

  Subsequently, an organic compound-containing liquid containing a hole injection material is selected on the pixel electrode 42 surrounded by the opening 47a by a nozzle printing apparatus that continuously flows or an inkjet apparatus that discharges the liquid as a plurality of individual droplets. Apply it. Subsequently, the light-emitting pixel substrate 31 is heated in an air atmosphere to volatilize the solvent of the organic compound-containing liquid, thereby forming the hole injection layer 43. The organic compound-containing liquid may be applied in a heated atmosphere.

  Subsequently, an organic compound-containing liquid containing a material that becomes the interlayer 44 is applied onto the hole injection layer 43 using a nozzle printing apparatus or an inkjet apparatus. The interlayer 44 is formed by performing heat drying in a nitrogen atmosphere or heat drying in a vacuum to remove the residual solvent. The organic compound-containing liquid may be applied in a heated atmosphere.

  Next, an organic compound-containing liquid containing a light emitting polymer material (R, G, B) is similarly applied by a nozzle printing device or an ink jet device and heated in a nitrogen atmosphere to remove the residual solvent, and the light emitting layer 45 is formed. The organic compound-containing liquid may be applied in a heated atmosphere.

  On the light emitting pixel substrate 31 formed up to the light emitting layer 45, the counter electrode 46 and the metal film 33a on the surface of the groove 31a on the light emitting pixel substrate 31 are collectively formed by vacuum deposition or sputtering using a metal mask. Accordingly, each of the counter electrode 46 and the metal film 33a has a two-layer structure including a layer made of a material having a low work function such as Li, Mg, Ca, Ba, and a light-reflective conductive layer such as Al. The metal film 33a may have a single-layer structure including only a light-reflective conductive layer such as Al.

  Next, a sealing resin made of an ultraviolet curable resin or a thermosetting resin is applied on the light emitting pixel substrate 31 outside the light emitting region where the plurality of light emitting pixels 30 are formed, and the light emitting pixel substrate 31 and the sealing substrate 32 are applied. And paste together. Next, the sealing resin is cured by ultraviolet rays or heat to join the light emitting pixel substrate 31 and the sealing substrate.

  Next, the bonded light emitting pixel substrate 31 and the sealing substrate 32 are placed in a furnace under a reduced pressure atmosphere of 1 to 100 Pa, and the working fluid 36 is injected from one of the working fluid inlets 34 and 34. In the present embodiment, since the injection ports are provided at two places, the gas in the narrow tube 33 is exhausted from one injection port, and the working fluid 36 is injected into the narrow tube 33 from the other injection port 34. At this time, in order to leave a space in the narrow tube 33 where the working fluid 36 can be vaporized, the working fluid 36 is not filled in the entire space of the narrow tube 33 but is injected so that there is a space without the working fluid 36 partially. In addition, the injection port may be provided only in one place, and may be provided more than two places. When the injection port is provided at one place, for example, the light emitting pixel substrate 31 and the sealing substrate 32 are arranged in a furnace under a reduced pressure atmosphere of 1 to 100 Pa, and immersed in the working liquid 36 so as to close the injection port. The inside of the furnace is returned to atmospheric pressure, and the working fluid 36 is injected into the narrow tube 33 due to a pressure difference between the inside and outside of the narrow tube 33.

After injecting the hydraulic fluid, the inlets 34 and 34 are sealed by the inlet sealing part 35.
From the above steps, the light emitting panel 21 is manufactured.

Thus, the manufactured light-emitting panel 21 is installed in the recess 22 a of the housing 22, and the heat transfer plate 24 is further installed on the sealing substrate 32 of the light-emitting panel 21. Next, the heat radiating plate 23 is installed in the recess 22 c of the housing 22 so as to contact the heat transfer plate 24. Further, the rod lens 25 is installed in the recess 22 b of the housing 22.
From the above, the light emitting unit 20 is manufactured.

  The light emitting unit 20 manufactured in this manner is combined with a photoconductor 11, a charging unit 12, a developing unit 13, a transfer unit 14, a fixing unit 16, a cleaner 17, and a static eliminator 18, thereby obtaining an image. A forming device is manufactured.

  As described above, in the manufacturing method of the image forming apparatus 10 of the present embodiment, the groove 32b is formed in the sealing substrate 32 for sealing the light emitting pixels 30, and the light emitting pixel substrate 31 and the sealing substrate 32 are sealed. By stopping, the thin tube 33 functioning as a heat pipe can be formed. The thin tubes 33 can favorably move the heat generated from the light emitting pixels 30 to the heat transfer plate 24, remove the heat generated from the light emitting pixels 30, and suppress the occurrence of temperature unevenness in the light emitting pixels 30. it can. Thereby, it is possible to suppress the occurrence of luminance unevenness due to the long life of the organic EL element of the light emitting pixel 30 and the temperature unevenness.

(Second Embodiment)
An image forming apparatus according to the second embodiment will be described below with reference to the drawings. The image forming apparatus of the present embodiment is different from the image forming apparatus of the first embodiment in that a part of the light emitting panel of the light emitting unit is formed of metal in the present embodiment. Portions common to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 11 shows a light emitting unit 81 used in the image forming apparatus of this embodiment. 12 is a plan view of the light emitting panel 82 of the present embodiment, and FIG. 13 is a cross-sectional view taken along line XIII-XIII shown in FIG.

  As shown in FIG. 11, the light emitting unit 20 of the present embodiment includes a light emitting panel 82, a housing 22 that holds the light emitting panel 82, a heat radiating plate 23, a heat transfer plate 24, and a rod lens 25.

  As shown in FIGS. 12 and 13, the light-emitting panel 82 includes a light-emitting pixel substrate 31, a light-emitting pixel 30, a sealing substrate 32 disposed to face the light-emitting pixel substrate 31, a thin tube 83, and a working liquid injection port 34. And an inlet sealing portion 35.

  As in the first embodiment, the light-emitting pixel substrate 31 is made of a light-transmitting substrate, such as a glass substrate. On the surface of the sealing substrate 31 facing the sealing substrate 32, grooves 31a that function as the narrow tubes 83a and 83b are formed as in the first embodiment. The groove 31a is formed to meander in a region adjacent to the light emitting pixel array, and is formed in a straight line in a region facing the heat transfer plate 24. The surface where the sealing substrate 32 and the metal plate 84 are in contact is bonded so that the sealed working fluid 36 does not leak. Thus, in the present embodiment, the groove 83 is formed by the groove 31 a formed in the light emitting pixel substrate 31, the sealing substrate 32, and the heat transfer plate 24.

  In this embodiment, the groove 31a is formed in the light emitting pixel substrate 31, and the light emitting pixel substrate 31, the sealing substrate 32, and the heat transfer plate 24 are sealed with a sealant, so that the groove 31a is formed into the narrow tubes 83a and 83b. It functions as a (cooling pipe). The thin tube 83 includes a thin tube 83a that is disposed on the light emitting pixel side and has a relatively large surface area by meandering, and a thin tube 33b that is disposed on the outer side of the light emitting panel 82 and is connected to the thin tube 83a. The narrow tube 83 is filled with a liquid (working fluid) that is easily vaporized under reduced pressure, such as water or alcohol. Thereby, the thin tube 83 functions as a heat pipe. As shown in FIG. 12, one of the thin tubes 83 is adjacent to the light emitting pixel 30 and is heated by heat generated from the light emitting pixel 30. Heat is dissipated from the heat sink 23 through the heat transfer plate 24 to the other of the thin tubes. Thereby, the other side of the thin tube 33 can be cooled. In this way, the working liquid 36 is vaporized by the thin tube 83a on the light emitting pixel side, the heat is absorbed, the working liquid 36 is liquefied by the thin tube 83b on the heat transfer plate side, and the heat is released. By repeating this heat absorption and heat dissipation, heat can be moved to the heat dissipation plate, heat generated from the light emitting pixels can be moved to the heat dissipation plate, and the light emitting pixels can be cooled. In the present embodiment, the heat can be released more efficiently by forming the heat releasing region from the metal plate, so that the heat can be favorably transferred from the light emitting pixel to the heat radiating plate. .

  As described above, in the image forming apparatus of the present embodiment, the thin tube 83 functioning as a heat pipe is formed on the light emitting panel 82 of the light emitting unit 80, so that the heat generated from the light emitting pixels 30 can be satisfactorily transmitted to the heat transfer plate 24. It is possible to suppress the occurrence of luminance unevenness due to the longer life of the organic EL element of the light emitting pixel 30 and the temperature unevenness. In particular, in the present embodiment, by forming the grooves 32c and 84a in the sealing substrate 32 and the metal plate 84, heat can be released to the heat transfer plate 24 more favorably, and the light emitting pixels 30 can be favorably cooled. can do.

The present invention is not limited to the above-described embodiments, and various modifications and applications are possible.
In the second embodiment described above, the configuration in which the groove 31a is formed in the light emitting pixel substrate 31 and the groove or the like is not formed in the heat transfer plate 24 has been described as an example. In addition, a groove 24 a may be formed in the heat transfer plate 24.

  In the above-described embodiment, the groove functioning as the heat pipe has been described as an example of the configuration formed only in the light emitting pixel substrate. However, the present invention is not limited thereto, and is formed in the sealing substrate and the light emitting pixel substrate, respectively. May be.

  In the second embodiment described above, the configuration in which the heat transfer plate 24 is sealed to the light emitting pixel substrate 31 is described as an example. However, the metal plate that seals the light emitting pixel substrate, the metal plate, and the heat dissipation It can also be divided into a heat transfer plate installed between the plates.

In each of the above-described embodiments, the light-emitting pixel circuit DS has been described as an example including a total of two transistors, that is, the selection transistor Tr11 and the light-emission driving transistor Tr12. May be.
In each of the embodiments described above, the light emitting unit is used as the exposure head. However, the present invention is not limited to this, and the light emitting panel can also be applied to an image display panel that displays a moving image or a still image.

1 is a plan view illustrating a configuration example of an image forming apparatus according to a first embodiment. It is a figure which shows typically the light emission part which concerns on 1st Embodiment. It is a top view which shows typically the light emission panel which concerns on 1st Embodiment. It is the IV-IV sectional view taken on the line shown in FIG. It is an equivalent circuit diagram of a luminescent pixel drive circuit. It is a top view which shows a light emitting pixel. It is the VII-VII sectional view taken on the line shown in FIG. It is a figure which shows the manufacturing method of the image forming apparatus which concerns on 1st Embodiment. It is a figure which shows the manufacturing method of the image forming apparatus which concerns on 1st Embodiment. It is a figure which shows the manufacturing method of the image forming apparatus which concerns on 1st Embodiment. It is a figure which shows the light emission part of the image forming apparatus which concerns on 2nd Embodiment. It is a top view which shows typically the light emission panel which concerns on 2nd Embodiment. It is the XIII-XIII sectional view taken on the line shown in FIG. It is a figure which shows a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Photoconductor, 13 ... Developing part, 14 ... Transfer part, 16 ... Fixing device, 17 ... Cleaner, 18 ... Static eliminator, 19 ... Transfer paper, 20, 81 ... Light emitting part, 21,82 ... Light emitting panel, 22 ... Housing, 23 ... Heat sink, 24,84 ... Heat transfer plate, 25 ... Rod lens, 30 ... luminescent pixel, 31 ... luminescent pixel substrate, 32 ... sealing substrate, 32a, 84a ... groove, 33, 83 ... capillary, 34 ... hydraulic fluid injection Inlet, 35... Injection port sealing portion, 41... Insulating film, 42... Pixel electrode, 43 .. hole injection layer, 44. ... Counter electrode, 47 ... Interlayer insulating film, 48 ... Partition, 61, 62, 63, 64 ... Contact hole, Cs. Capacitors, La · · · anode lines, Ld · · · data lines, Lg · · · gate lines, Tr11 · · · select transistors, Tr12 · · · emission driving transistor

Claims (6)

A luminescent pixel;
A light emitting pixel substrate formed with a groove having a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove ;
A sealing substrate for sealing the first groove portion of the light emitting pixel substrate;
A volatile liquid enclosed in the groove,
Furthermore, the heat transfer plate disposed so as to contact the sealing substrate at a position facing the second groove portion of the light emitting pixel substrate, or the light emitting pixel substrate facing the second groove portion of the light emitting pixel substrate. One of the heat transfer plates made of a metal plate arranged to contact,
A light emitting part having a heat radiating plate in contact with the surface opposite to the surface facing the second groove of the heat transfer plate ,
The heat transfer plate, and characterized that you transfer heat from the gas to move the volatile liquid is vaporized in the second groove in said first groove portion by the heat emitted from the light emitting pixels on the heat radiating plate Image forming apparatus.   The image forming apparatus according to claim 1, wherein the sealing substrate and the light emitting pixel substrate are bonded by an adhesive member.   The image forming apparatus according to claim 1, wherein a metal film is formed on a surface of the groove formed in the light emitting pixel substrate. Wherein in a region facing the light emitting pixels on the sealing substrate, the image forming apparatus according to any one of claims 1 to 3, characterized in that recesses are formed. Forming a light emitting pixel on the light emitting pixel substrate;
On the surface of the light emitting pixel substrate facing the sealing substrate, a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove. Forming a groove having ,
Sealing the groove of the light emitting pixel substrate and the sealing substrate;
A step of encapsulating the volatile liquid in the groove,
Disposing a heat transfer plate in contact with the sealing substrate at a position facing the second groove of the light emitting pixel substrate;
And a step of contacting a heat radiating plate to a surface opposite to the surface facing the second groove of the heat transfer plate .   Forming a light emitting pixel on the light emitting pixel substrate;
  On the surface of the light emitting pixel substrate facing the sealing substrate, a first groove located on the light emitting pixel side, and a second groove connected to the first groove and separated from the light emitting pixel by the first groove. Forming a groove having,
  Sealing the first groove portion of the light emitting pixel substrate and the sealing substrate, and sealing the second groove portion of the light emitting pixel substrate and a heat transfer plate made of a metal plate;
  Enclosing a volatile liquid in the groove;
  And a step of contacting a heat radiating plate to a surface opposite to the surface facing the second groove of the heat transfer plate.

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