JP2009272151A - Surface light-emitting device, method of driving the same, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface light-emitting device composed of an organic electroluminescent element which can show the exchange timing of a light source without increasing the number of components, and to provide a method of driving the same. <P>SOLUTION: The surface light-emitting device 200 includes a substrate 20, a surface light-emitting part 201 which is installed on one of faces of the substrate 20 and composed of an organic electroluminescent element, an outer frame part 202 which is installed on one of faces of the substrate 20 and surrounds the surface light-emitting part 201, and a resistance change detection means 207 at a part of the outer frame part 202. The resistance change detection means 207 has a set of organic electroluminescent elements 203A, 203B connected in parallel, and a resistive element is connected to either one of the positive electrode of the set of the organic electroluminescent elements 203A, 203B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface light emitting device, a driving method thereof, and an electronic apparatus.

In recent years, organic electroluminescence elements are light, thin, and have low power consumption, so that they have been applied not only to flat display devices but also to surface-emitting illumination devices (hereinafter referred to as surface light-emitting devices) in recent years.
However, a surface light emitting device using an organic electroluminescence element still has a problem in the luminance life and a reduction in brightness is faster than a general lighting device.

  When a surface emitting device is considered as a product, it will be used for a long time, so it becomes a problem at which point the light source should be replaced. In the case of a general lighting device, the light source is replaced when it becomes sensuously dark, not when no light is emitted.

Patent Literature 1 and Patent Literature 2 disclose a method of notifying the replacement timing of the light source of the lighting device. Patent Document 1 is an invention about an illumination control system with an energy saving function, and includes a system that measures the illuminance of a light source using an illuminance sensor and adjusts the illuminance according to the measurement result. Moreover, patent document 2 is invention about the illumination replacement | exchange time specific system, and is provided with the illumination intensity control part which makes the illumination intensity of a light source become constant. In any of the inventions, it is necessary to construct an illuminance sensor and a system in addition to the light source, and the number of parts and man-hours increases, so that the manufacturing process becomes complicated and the manufacturing cost increases.
JP 2002-1000048 A1 JP 2007-59133 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a surface light-emitting device including an organic electroluminescence element that can indicate the replacement timing of a light source without increasing the number of components, and a driving method thereof. And

In order to achieve the above object, the present invention employs the following configuration. That is,
The surface light-emitting device of the present invention includes a substrate, a surface light-emitting portion provided on one surface of the substrate and made of an organic electroluminescence element, and an outer frame provided on one surface of the substrate and surrounding the surface light-emitting portion. And a resistance value change detecting means in a part of the outer frame part, the resistance value change detecting means having a set of organic electroluminescence elements connected in parallel, A resistance element is connected to the anode of any one of the organic electroluminescence elements.

  The surface light-emitting device of the present invention includes a set of organic electroluminescence elements connected in parallel, and a resistance value in which a resistance element is connected to one of the anodes of the set of organic electroluminescence elements Since the change detection means is provided, the voltage (effective voltage) applied to the organic compound layer (functional layer) of the organic electroluminescence element to which the resistance element is not connected is changed to the organic electroluminescence to which the resistance element is connected. It can be made larger than the voltage (effective voltage) applied to the organic compound layer (functional layer) of the element. Thereby, the deterioration of the organic electroluminescence element to which the resistance element is not connected becomes faster than the deterioration of the organic electroluminescence element to which the resistance element is connected. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the set of organic electroluminescence elements can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit without increasing the number of parts.

  In the surface light emitting device of the present invention, the work function of the cathode material of the organic electroluminescence element to which the resistance element is connected is larger than the work function of the cathode material of the organic electroluminescence element to which the resistance element is not connected. Features.

  The surface light emitting device of the present invention has a configuration in which the work function of the cathode material of the organic electroluminescence element to which the resistance element is connected is larger than the work function of the cathode material of the organic electroluminescence element to which the resistance element is not connected. The voltage (effective voltage) applied to the organic compound layer (functional layer) of the organic electroluminescence element to which the element is not connected is applied to the organic compound layer (functional layer) of the organic electroluminescence element to which the resistance element is connected. Can be made larger than the voltage (effective voltage). Thereby, the deterioration of the organic electroluminescence element to which the resistance element is not connected becomes faster than the deterioration of the organic electroluminescence element to which the resistance element is connected. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the set of organic electroluminescence elements can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit without increasing the number of parts.

  The surface light-emitting device of the present invention includes a substrate, a surface light-emitting portion provided on one surface of the substrate and made of an organic electroluminescence element, and an outer frame provided on one surface of the substrate and surrounding the surface light-emitting portion. And a resistance value change detecting means in a part of the outer frame part, the resistance value change detecting means having a set of organic electroluminescence elements connected in parallel, The work function of the cathode material of any one of the organic electroluminescent elements is larger than the work function of the cathode material of the other organic electroluminescent element.

  The surface light-emitting device of the present invention includes a set of organic electroluminescence elements connected in parallel, and the work function of one of the cathode materials of the set of organic electroluminescence elements is the other organic electroluminescence element. Since the work function of the cathode material of the luminescence element is larger than the work function of the cathode material, the voltage (effective voltage) applied to the organic compound layer (functional layer) of the organic electroluminescence element having a small work function of the cathode material is The voltage (effective voltage) applied to the organic compound layer (functional layer) of a large organic electroluminescence element can be increased. Thereby, the deterioration of the organic electroluminescence element having a small work function of the cathode material is earlier than the deterioration of the organic electroluminescence element having a large work function of the cathode material. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the set of organic electroluminescence elements can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit without increasing the number of parts.

The surface light-emitting device of the present invention is characterized in that light emission colors of a set of organic electroluminescence elements provided in the resistance value change detecting means are different.
The surface light-emitting device of the present invention has a configuration in which the light emission color of the set of organic electroluminescence elements provided in the resistance value change detection means is different, and therefore recognizes the change in the light emission color as the light emission luminance changes. Thus, it is possible to more easily recognize the replacement time of the surface light emitting part without increasing the number of parts.

An electronic apparatus according to the present invention includes the surface light emitting device described above.
Since the electronic device of the present invention includes the surface light emitting device described above, it is possible to more easily recognize the replacement time of the surface light emitting unit without increasing the number of components.

  The surface light emitting device driving method of the present invention is the surface light emitting device driving method described above, and is provided in the resistance value change detecting means in conjunction with the light emission of the organic electroluminescence element of the surface light emitting portion. The set of organic electroluminescence elements emits light, and after a predetermined time of light emission, the magnitude of light emission luminance of the set of organic electroluminescence elements provided in the resistance value change detecting means is switched. .

  In the driving method of the surface light-emitting device of the present invention, the set of organic electroluminescence elements provided in the resistance value change detecting means emits light in conjunction with light emission of the organic electroluminescence elements of the surface light-emitting unit, and is constant. After the light emission for a period of time, the set of organic electroluminescence elements provided in the resistance value change detecting means is switched in magnitude, so that the set of organic electroluminescence provided in the resistance value change detecting means. By recognizing the switching of the emission luminance of the luminescence element, it is possible to easily recognize the replacement time of the surface light emitting unit without increasing the number of components.

  According to said structure, the surface emitting apparatus which consists of an organic electroluminescent element which can show the replacement time of a surface emitting part, and its drive method can be provided, without increasing the number of parts.

Hereinafter, modes for carrying out the present invention will be described.
In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

<Embodiment 1>
FIG. 1 is a plan view showing an example of a surface light emitting device according to an embodiment of the present invention.
As shown in FIG. 1, a surface light emitting device 200 according to an embodiment of the present invention includes a surface light emitting unit 201 made of an organic electroluminescence element and an outer frame portion 202 surrounding the surface light emitting unit 201 on a substrate. A replacement time display unit (resistance value change detecting means) 207 indicating the replacement time of the surface light emitting unit 201 is provided in a part of the outer frame unit 202.

FIG. 2 is an enlarged plan view of the replacement time display unit 207 of FIG.
The replacement time display unit 207 includes a pair of organic electroluminescence elements 203A and 203B connected in parallel, and a resistance element (not shown) is provided on one anode of the pair of organic electroluminescence elements 203A and 203B. ) Is connected. In order to make the description easy to understand, the following description will be given on the assumption that a resistance element is connected to the organic electroluminescence element 203B.

A set of organic electroluminescence elements 203A and 203B are connected in parallel, and a resistance element is connected to the organic electroluminescence element 203B, so that it is actually applied to the organic compound layer (functional layer) of the organic electroluminescence element. The applied voltage (effective voltage) of the organic electroluminescence element 203A to which the resistance element is not connected is larger than that of the organic electroluminescence element 203B to which the resistance element is connected.
Thereby, the initial luminance of the organic electroluminescence element 203A to which the resistance element is not connected becomes larger than the initial luminance of the organic electroluminescence element 203B to which the resistance element is connected.

  In addition, since the voltage (effective voltage) applied to the organic electroluminescence element 203A to which the resistance element is not connected is larger than the voltage (effective voltage) applied to the organic electroluminescence element 203B to which the resistance element is not connected, it is constant time. The deterioration of the organic electroluminescence element when the light is emitted is faster in the organic electroluminescence element 203A to which the resistance element is not connected than in the organic electroluminescence element 203B to which the resistance element is connected.

That is, the deterioration rate of the organic electroluminescence element 203A to which the resistance element is not connected is larger than the deterioration speed of the organic electroluminescence element 203B to which the resistance element is connected, and the luminance is half the initial luminance. The period until (half-life) is shortened.
By controlling the conditions such as the resistance value and the driving voltage of the resistance element, the luminance of the organic electroluminescence element 203A to which the resistance element is not connected in the half life of the organic electroluminescence element 203A to which the resistance element is not connected, The magnitude of the luminance of the organic electroluminescence element 203B to which the resistance element is connected can be switched.

  It is preferable that the pair of organic electroluminescence elements 203A and 203B provided in the replacement time display unit 207 emit light in conjunction with light emission of the organic electroluminescence element of the surface light emitting unit 201. Thereby, by controlling the conditions such as the resistance value and the driving voltage of the resistance element, the luminance of the organic electroluminescence element of the surface light emitting unit 201 is initially set in the half life of the organic electroluminescence element 203A to which the resistance element is not connected. The value can be set to half of the luminance.

  The set of organic electroluminescence elements 203A and 203B of the replacement time display unit 207 may have a material and a structure different from those of the organic electroluminescence elements of the surface light emitting unit 201, but the set of organic electroluminescence elements of the replacement time display unit 207 203A and 203B may have the same material and structure as those of the organic electroluminescence element of the surface light emitting unit 201.

  Thus, the organic electroluminescence element provided in the replacement time display unit 207 is driven by driving the pair of organic electroluminescence elements 203A and 203B of the replacement time display unit 207 under the same conditions as the organic electroluminescence elements of the surface light emitting unit 201. The switching point of the emission luminance of the luminescence element can be the half-life of the organic electroluminescence element of the surface light emitting part 201, and the replacement time of the surface light emitting part can be easily recognized without increasing the number of parts. be able to.

FIG. 3 is a diagram illustrating an example of the replacement time display unit 207, and is a schematic cross-sectional view taken along the line BB ′ of FIG.
As shown in FIG. 3, the replacement time display unit 207 is formed with a pair of organic electroluminescence elements 203A and 203B connected in parallel. In the organic electroluminescence elements 203A and 203B, an organic compound layer (functional layer) 12 including a hole injection layer 32 and a light emitting layer 30 is formed on the pixel electrode 10 formed on the substrate 20, and an organic compound layer ( A common electrode 50 is formed on the functional layer 12. The organic electroluminescence elements 203 </ b> A and 203 </ b> B are spaced apart by the pixel partition layer 22 and the common partition layer 24. The common electrode 50 includes an electron injection electrode 50A and a cathode 50B. In the following description, the upper and lower relations and the stacking relations of the respective components are shown with the side on which the substrate 20 is arranged as the lower side and the side on which the common electrode 50 is arranged as the upper side. Hereinafter, each component will be described in order.

<Board>
The substrate 20 includes a substrate body 20A and an element layer 20B formed on the substrate body substrate body 20A.

<Board body>
As the substrate body 20A, either a transparent substrate or an opaque substrate can be used.
As the transparent substrate, for example, an inorganic substance such as glass, quartz glass, or silicon nitride, or an organic polymer (resin) such as an acrylic resin or a polycarbonate resin can be used. In addition, a composite material formed by laminating or mixing the above materials can be used as long as it has optical transparency. In addition, as the opaque substrate, for example, ceramics such as alumina, a metal sheet such as stainless steel, which has been subjected to insulation treatment such as surface oxidation, thermosetting resin or thermoplastic resin, and its film (plastic film), etc. Is mentioned.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the substrate body 20A is formed using glass.

<Element layer>
The element layer 20B includes various wirings and driving elements for driving the organic electroluminescence elements 203A and 203B, and an inorganic or organic insulating film. Various wirings and driving elements can be appropriately formed by patterning by photolithography and then etching, and the insulating film can be appropriately formed by a generally known method such as vapor deposition or sputtering.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, a resistance element (not shown) is provided in the element layer 20B, and is connected to the pixel electrode 10 (anode) of the organic electroluminescence element 203B. Yes.

<Pixel electrode>
A pixel electrode 10 is formed on the element layer 20B. As a material for forming the pixel electrode 10, it is preferable to use a material having a work function of 5 eV or more. This is because a material having a work function of 5 eV or more has a high hole injection effect. Examples of such a material include metal oxides such as ITO (Indium Tin Oxide).
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the pixel electrode 10 is formed using ITO.

<Pixel partition layer>
In addition, a pixel partition layer 22 is formed on the element layer 20B so that a part of the pixel electrode 10 runs over the end portion of the pixel electrode 10. The pixel partition layer 22 includes an opening corresponding to the pixel electrode 10, and the pixel electrode 10 is exposed in the opening. The pixel partition layer 22 is formed of an inorganic insulating material such as silicon oxide (SiO ₂ ), silicon nitride (SiN), or silicon oxynitride (SiON), and is used for etching through a mask corresponding to the position of the opening. It can be formed by a known method.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the pixel partition layer 22 is formed using SiO ₂ .

<Common partition layer>
On the pixel partition layer 22, a common partition layer 24 is formed so as to surround the periphery of the pixel electrode 10. The common partition layer 24 is a partition for electrically insulating the pixel electrodes 10 (anode), and the cross-sectional shape is formed in a forward tapered shape. Therefore, the space surrounded by the common partition wall layer 24 is wider at the top than at the bottom. The top surface 24a of the common partition wall layer 24 is formed into a hole injection layer solution (functional liquid) and a light emitting layer solution (functional liquid) containing a material for forming a hole injection layer (functional layer) and a light emitting layer (functional layer) described later. It is formed so as to exhibit liquid repellency.
For example, the common partition wall layer 24 may be formed of a resin having liquid repellency such as a fluorine-containing resin, or after being formed of a photocurable acrylic resin or polyimide resin, plasma is generated under O ₂ gas. After the treatment, CF ₄ plasma treatment or the like may be applied to impart liquid repellency.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, after the common partition wall layer 24 is formed of acrylic resin, a liquid repellent process is performed by a CF ₄ plasma process.

<Organic compound layer (functional layer)>
The organic compound layer (functional layer) 12 includes a hole injection layer (functional layer) 32 that facilitates injection of holes from the pixel electrode 10 and a light emitting layer (functional layer) 30. Are stacked in this order.

<Hole injection layer>
The surface exposed to the bottom surface of the region surrounded by the common partition wall layer 24 (here, part of the pixel electrode 10 and the pixel partition wall layer 22) is in contact with the side wall 24b to inject holes from the pixel electrode 10. A hole injection layer 32 is formed as an easy charge transfer layer. The hole injection layer 32 is formed by applying a hole injection layer solution (functional liquid) in which a material for forming the hole injection layer is dissolved or dispersed from the droplet discharge head and then evaporating the solvent.

The hole injection layer 32 is formed by applying a solution (functional liquid) of a material for forming the hole injection layer from the droplet discharge head and evaporating the solvent. The material for forming the hole injection layer 32 is polyphenylene vinylene whose polymer precursor is polytetrahydrothiophenylphenylene, 1,1-bis- (4-N, N-ditolylaminophenyl) cyclohexane, tris (8-hydroxyquinolinol). ) Known materials such as aluminum, polystyrene sulfonic acid, a mixture of polyethylene dioxythiophene and polystyrene sulfonic acid (PEDOT / PSS) can be exemplified. Moreover, as a solvent which dissolves these at the time of application | coating, polar solvents, such as water, isopropyl alcohol, N-methylpyrrolidone, 1, 3- dimethyl- imidazolinone, can be illustrated.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the hole injection layer 32 is formed using PEDOT / PSS.

<Light emitting layer>
On the hole injection layer 32, the light emitting layer 30 is formed in contact with the side wall 24b. The light emitting layer 30 is also formed by evaporating the solvent after applying a solution (functional liquid) of a material for forming the light emitting layer.
As a material for forming the light emitting layer 30, a known polymer light emitting material capable of emitting fluorescence or phosphorescence can be suitably used.
Such materials include polyfluorene (PF), polyparaphenylene vinylene (PPV), polyphenylene (PP), polyparaphenylene (PPP), polyvinylcarbazole (PVK), polythiophene, polydialkylfluorene (PDAF), polyfluorene. Examples thereof include benzothiadiazole (PFBT), polyalkylthiophene (PAT), and polysilanes such as polymethylphenylsilane (PMPS).
In addition, these luminescent materials include low-molecular organic luminescent dyes such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, A low molecular material such as quinacridone can also be used by doping.

As the solvent, for example, a nonpolar solvent such as cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, or tetramethylbenzene can be used. Two or more kinds may be appropriately mixed to adjust the viscosity.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the light emitting layer 30 is formed using polyfluorene (PF).

<Common electrode>
The common electrode (cathode) 50 includes an electron injection cathode 50A that covers the top surface 24a and the side wall 24b of the common partition wall layer 24 and covers the entire upper surface of the light emitting layer 30, and a cathode that covers the entire surface of the electron injection cathode 50A. 50B is provided.

<Electron injection cathode>
On the light emitting layer 30, an electron injection cathode 50a is formed on the entire surface so as to cover the top surface 24a and the side wall 24b of the common partition wall layer 24. The electron injection cathode 50a can be formed using an alkali metal, an alkaline earth metal, a fluoride or an oxide of the metal, or the like.
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the electron injection cathode 50a is made of Ca and has a thickness of 5 nm.

<Cathode>
A cathode 50b is formed on the electron injection cathode layer 50a so as to cover the entire surface of the electron injection cathode layer 50a. The cathode 50b is made of a metal material having good conductivity such as Al or Cu. The cathode 50b is connected to a cathode contact portion connected to a cathode take-out terminal (not shown).
In the replacement time display unit 207 of the surface light emitting device 200 according to the embodiment of the present invention, the cathode 50b is made of Al and has a thickness of 200 nm.

In addition, the common electrode (cathode) 50 of the organic electroluminescence elements 203A and 203B is arranged separately in parallel, and is configured so that a voltage can be applied independently.
When the common electrode (cathode) 50 is formed, the cathode material is vapor-deposited using a mask in which the cathodes are arranged in parallel, so that the cathodes arranged in parallel can be formed. Alternatively, a reverse-tapered partition wall formed in advance on the top surface 24a of the common partition wall layer 24 can also form cathodes that are separated and arranged in parallel.
By forming the replacement time display unit 207 having the above configuration, the surface light emitting device 200 according to the embodiment of the present invention can be formed.

  FIG. 4 is a circuit diagram illustrating an example of the replacement time display unit 207. A portion surrounded by a dotted line 70 is a diagram illustrating an example of a circuit portion of the organic electroluminescence elements 203A and 203B. The organic electroluminescence elements 203A and 203B are arranged in parallel and are electrically connected. One of the organic compound layers (functional layers) 12 of the organic electroluminescence elements 203 </ b> A and 203 </ b> B is connected to the common electrode (cathode) 50 and the other is connected to the pixel electrode (anode) 10.

Except for the portion surrounded by the dotted line 70, it is a diagram showing an example of the circuit structure of the element portion 20B.
As shown in FIG. 4, in the replacement time display unit 207, a plurality of scanning lines 101, a signal line 102 extending in a direction intersecting with these scanning lines 101, and a common power supply line 103 extending in parallel with these signal lines 102. And are wired. A pixel region X is provided at the intersection of the scanning line 101 and the signal line 102.

For the signal line 102, a data side driving circuit 100 including a shift register, a level shifter, a video line, an analog switch, and the like is provided. On the other hand, for the scanning line 101, a scanning side driving circuit 80 including a shift register, a level shifter, and the like is provided.
Each pixel region X is supplied with a switching TFT (thin film transistor) 112 to which a scanning signal (power) is supplied to the gate electrode via the scanning line 101, and from the signal line 102 via this switching TFT 112. A storage capacitor 113 for holding the image signal and a driving TFT 123 for supplying the image signal held by the storage capacitor 113 to the gate electrode are provided.

  Under such a configuration, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential (power) of the signal line 102 at that time is held in the holding capacitor 113, and the state of the holding capacitor 113 is reached. Accordingly, the on / off state of the driving TFT 123 is determined. Then, a current (power) flows from the common power supply line 103 to the pixel electrode 10 through the channel of the driving TFT 123, and a current flows to the cathode 50 through the organic compound layer (functional layer) 12 of the organic electroluminescence elements 203 A and 203 B. Thus, the light emitting layer in the organic compound layer (functional layer) 12 emits light according to the amount of current flowing therethrough.

In the organic electroluminescence element 203 </ b> A, a drive current flows from the common power supply line 103 to the pixel electrode (anode) 10 when electrically connected to the common power supply line 103 via the driving TFT 123.
However, in the organic electroluminescence element 203B, since the resistance element 205 is connected between the pixel electrode (anode) 10 and the driving TFT 123, when electrically connected to the common power supply line 103 via the driving TFT 123, In addition, a drive current flows from the common power supply line 103 to the pixel electrode (anode) 10 via the resistance element 205.

  As a result, when a voltage is applied to drive the organic electroluminescence elements 203A and 203B, a current flows mainly through the organic electroluminescence element 203A to which the resistance element 205 is not connected. Therefore, the emission luminance from the organic electroluminescence element 203A is organic. It becomes larger than the light emission luminance from the electroluminescence element 203B.

  When light is emitted for a certain period of time in this state, a high electric field is applied by the organic electroluminescence element 203A. Therefore, the drive deterioration of the organic electroluminescence element 203A is more severe than the drive deterioration of the organic electroluminescence element 203B. The increase in the resistance value of the electroluminescence element 203A becomes faster and more rapid than the increase in the resistance value of the organic electroluminescence element 203B.

FIG. 5 is a graph showing an example of a change in the drive voltage with respect to the drive time when the drive voltage is controlled so that the light emission luminance is constant. At the drive start time (t = 0), the drive voltage is V ₀ , and the drive voltage does not change so much even if light is emitted for a certain period of time. However, at the time point t = t ₁ , the drive voltage rapidly increases and reaches a value V _max that exceeds the measurement limit.
The organic electroluminescent device 203A, since 203B are connected in parallel, when the driving voltage of the organic electroluminescent device 203A abruptly increases at t = t ₁ point, the organic compound layer of the organic electroluminescence element 203B (Function The voltage (effective voltage) applied to the (layer) 12 also increases rapidly.

Since the organic electroluminescence element 203B is in a state in which the driving is not deteriorated as compared with the organic electroluminescence element 203A, as the voltage (effective voltage) applied to the organic compound layer (functional layer) 12 of the organic electroluminescence element 203B increases. The light emission luminance can be made larger than the light emission luminance of the organic electroluminescence element 203A.
In other words, the resistance value of the organic compound layer (functional layer) 12 of the organic electroluminescence element 203A is based on the total value of the resistance value of the organic compound layer (functional layer) 12 of the organic electroluminescence element 203B and the resistance value of the resistance element 205. The organic electroluminescent element driven when it becomes high switches.

  When a light emitting material having a different light emitting color is used as the light emitting material of the light emitting layer of the organic electroluminescent elements 203A and 203B, the switching of the light emitting color can be recognized by the switching of the driven organic electroluminescent element, The replacement time of the surface light emitting unit can be recognized more easily without increasing the number of parts.

Next, an example of a manufacturing process of the surface light emitting device 200 according to the embodiment of the present invention will be described. In addition, the reaction conditions of each process mentioned in the following manufacturing methods are examples, and are not limited to this.
First, a thin film made of ITO is formed on the element layer 20B using a dry film forming method such as sputtering, and then patterned by a known method, and an anode (pixel electrode) made of ITO is displayed on the replacement time display portion 207. ) 10 is formed.
Next, in order to prevent a short circuit between the anodes (pixel electrodes) 10 made of ITO, a pixel partition layer 22 made of an SiO ₂ insulating layer is formed on the peripheral portion of the anode (pixel electrode) 10 made of ITO.

Further, a common partition layer 24 made of an acrylic resin having a forward tapered cross-sectional shape is formed on the pixel partition layer 22 so as to separate the anodes. A recess provided by forming the common partition layer 24 is used as a film formation region of each pixel.
The substrate on which the pixel partition layer 22 and the common partition layer 24 are formed is first plasma-treated in an O ₂ atmosphere and then plasma-treated in a CF ₄ atmosphere. By these plasma treatments, the surface of ITO and SiO ₂ can be modified to be hydrophilic, and the surface of the common partition wall layer 24 can be modified to be water-repellent. Film formation is possible.

Next, a PEDOT / PSS dispersion liquid (functional liquid) is applied onto the anode (pixel electrode) 10 made of ITO by a droplet discharge method. Thereafter, this is dried and further baked to form the hole injection layer 32. Firing is performed, for example, by heating at 200 ° C. for 10 minutes in the air on a hot plate. Subsequently, a light emitting layer solution (functional liquid) is applied onto the hole injection layer 32 by a droplet discharge method. This is dried and further baked (annealing treatment) to form the light emitting layer 30. In the annealing treatment, for example, heating is performed at 130 ° C. for 1 hour on a hot plate in a nitrogen atmosphere. An organic compound layer (functional layer) 12 is formed from the hole injection layer 32 and the light emitting layer 30.
Finally, after 5 nm of Ca as an electron injecting cathode is formed on the light emitting layer 30 by vacuum deposition, 200 nm of cathode Al is continuously formed.

  A surface light emitting device 200 according to an embodiment of the present invention includes a set of organic electroluminescence elements 203A and 203B connected in parallel, and one of the set of organic electroluminescence elements 203A and 203B. Since the replacement time display unit 207 in which the resistance element 205 is connected to the anode is provided, the voltage applied to the organic compound layer (functional layer) 12 of the organic electroluminescence element to which the resistance element 205 is not connected ( (Effective voltage) can be made larger than the voltage (effective voltage) applied to the organic compound layer (functional layer) of the organic electroluminescence element to which the resistance element 205 is connected. Thereby, the deterioration of the organic electroluminescence element to which the resistance element 205 is not connected becomes faster than the deterioration of the organic electroluminescence element to which the resistance element 205 is connected. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the set of organic electroluminescence elements can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit 201 without increasing the number of parts.

  In the surface light emitting device 200 according to the embodiment of the present invention, the work function of the cathode material of the organic electroluminescence element to which the resistance element 205 is connected is the work function of the cathode material of the organic electroluminescence element to which the resistance element 205 is not connected. Therefore, the voltage (effective voltage) applied to the organic compound layer (functional layer) 12 of the organic electroluminescence element to which the resistance element 205 is not connected is the same as that of the organic electroluminescence element to which the resistance element 205 is connected. The voltage can be made larger than the voltage (effective voltage) applied to the organic compound layer (functional layer 12). Thereby, the deterioration of the organic electroluminescence element to which the resistance element 205 is not connected becomes faster than the deterioration of the organic electroluminescence element to which the resistance element 205 is connected. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the set of organic electroluminescence elements 203A and 203B can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit 201 without increasing the number of parts.

  The surface light emitting device 200 according to the embodiment of the present invention has a configuration in which the light emission colors of the pair of organic electroluminescence elements provided in the replacement time display unit 207 are different. Can be recognized, and the replacement time of the surface light emitting unit 201 can be more easily recognized without increasing the number of components.

  Further, in the present embodiment, the functional liquid is arranged using the droplet discharge method, but the present invention is not limited to this, and other wet coating methods such as screen printing, gravure printing, flexographic printing, dispenser method, etc. May be used.

<Embodiment 2>
The surface light emitting device 200 is manufactured in the same manner as in the first embodiment except that the common electrode 50 of the organic electroluminescence element 203B is formed of an MgAg alloy and the resistance element 205 is not connected.
Even in such a configuration, since the work function of the cathode material MgAg of the organic electroluminescence element 203B is larger than the work function of the cathode material Ca (Al) of the organic electroluminescence element 203A, the organic compound layer of the organic electroluminescence element 203A The voltage (effective voltage) applied to the (functional layer) 12 can be made larger than the voltage (effective voltage) applied to the organic compound layer (functional layer) 12 of the organic electroluminescence element 203B.

  Accordingly, the deterioration of the organic electroluminescence element 203A is faster than the deterioration of the organic electroluminescence element 203B. Therefore, the magnitude of the emission luminance of the pair of organic electroluminescence elements 203A and 203B can be switched after a certain period of light emission. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit 201 without increasing the number of parts.

<Embodiment 3>
The surface emitting device 200 is manufactured in the same manner as in the first embodiment except that the common electrode 50 of the organic electroluminescence element 203B is formed of an MgAg alloy.
The work function of the cathode material MgAg of the organic electroluminescence element 203B to which the resistance element 205 is connected is larger than the work function of the cathode material Ca (Al) of the organic electroluminescence element 203A to which the resistance element 205 is not connected. The voltage (effective voltage) applied to the organic compound layer (functional layer) 12 of the organic electroluminescence element 203A to which the element 205 is not connected is changed to the organic compound layer (function) of the organic electroluminescence element 203B to which the resistance element 205 is connected. The voltage (effective voltage) applied to the (layer) 12 can be made larger.

  Thereby, the deterioration of the organic electroluminescence element 203A to which the resistance element 205 is not connected becomes faster than the deterioration of the organic electroluminescence element 203B to which the resistance element 205 is connected. Therefore, after the light emission for a certain time, the magnitude of the light emission luminance of the pair of organic electroluminescence elements 203A and 203B in the replacement time display unit 207 can be switched. Thereby, it is possible to easily indicate the replacement time of the surface light emitting unit 201 without increasing the number of parts.

[Electronics]
The surface light-emitting device according to the embodiment of the present invention can be applied not only to a lighting device but also to various electronic devices. An electronic apparatus provided with a surface light emitting device according to an embodiment of the present invention will be described with an example. FIG. 6 is a schematic configuration diagram illustrating an image forming apparatus (optical printer) 1000 including the surface light emitting device as a line head.

The optical printer 1000 includes a photosensitive drum 1160 as an image carrier in the vicinity of the travel path of the transfer medium 1220. Around the photosensitive drum 1160, an exposure device 1100L, a developing device 1180, and a transfer roller 1210 are sequentially arranged along the rotation direction of the photosensitive drum 1160 (the arrow direction in the drawing). The photosensitive drum 1160 is rotatably provided around the rotation shaft 1170, and a photosensitive surface 1160A is formed on the outer peripheral surface of the photosensitive drum 1160 at the central portion in the rotation axis direction.
The exposure device 1100L and the developing device 1180 are arranged in a long axis shape along the rotation axis 1170 of the photosensitive drum 1160, and the width in the long axis direction substantially coincides with the width of the photosensitive surface 1160A.

The exposure apparatus 1100L has a line head (surface emitting device) 1100 having a plurality of organic EL elements 1100A and an image having a plurality of lens elements 1120A for imaging the light emitted from the line head 1100 at an erecting equal magnification. An optical element 1120. The line head 1100 and the imaging optical element 1120 are held by a head case (not shown) while being aligned with each other, and are fixed on the photosensitive drum 1160.
Here, the line head (surface emitting device) 1100 having the organic EL element 1100A is manufactured by the above-described manufacturing method, and has a replacement time display unit, which is omitted in the drawing. Therefore, the optical printer 1000 can easily indicate the replacement time of the surface light emitting unit without increasing the number of components.

  FIG. 7A is a perspective view showing an example of a mobile phone. In FIG. 7A, the mobile phone 2050 includes a display unit 2051. The display unit 2051 includes the surface light emitting device according to the present invention.

  FIG. 7B is a perspective view illustrating an example of a portable information processing apparatus such as a word processor or a personal computer. In FIG. 7B, the information processing apparatus 2060 includes an input unit 2061 such as a keyboard, a display unit 2062, and a housing 2063. The display unit 2062 includes the surface light emitting device according to the present invention.

  FIG. 7C is a perspective view showing an example of a wristwatch type electronic device. In FIG. 7C, the timepiece 2070 includes a display unit 2071. The display unit 2071 includes the surface light emitting device according to the present invention.

  Each of the electronic devices shown in FIGS. 7A to 7C is provided with the surface light-emitting device described in the above-described embodiment, and thus the surface light-emitting unit 201 can be easily formed without increasing the number of components. The electronic device can indicate the replacement time.

  The electronic device is not limited to the electronic device, and can be applied to various electronic devices. For example, a desktop computer, a liquid crystal projector, a multimedia personal computer (PC) and an engineering workstation (EWS), a pager, a word processor, a television, a viewfinder type or a monitor direct view type video tape recorder, an electronic notebook, an electronic The present invention can be applied to electronic devices such as a desktop computer, a car navigation device, a POS terminal, and a device having a touch panel.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

It is a top view which shows the surface light-emitting device which is embodiment of this invention. It is a top view which shows the replacement time display part of the surface emitting device which is embodiment of this invention. It is sectional drawing which shows the replacement time display part of the surface emitting device which is embodiment of this invention. It is a circuit diagram which shows the replacement time display part of the surface emitting device which is embodiment of this invention. It is a graph which shows the relationship between the drive voltage and drive time of an organic electroluminescent element. It is a figure which shows an electronic device provided with the surface emitting device which is embodiment of this invention. It is a figure which shows an electronic device provided with the surface emitting device which is embodiment of this invention.

DESCRIPTION OF SYMBOLS 10 ... Pixel electrode (anode), 12 ... Functional layer, 20 ... Substrate, 20A ... Substrate body, 20B ... Element layer, 22 ... Pixel partition layer, 24 ... Common partition layer, 24a ... Top surface, 24b ... Side wall, 30 ... Light emitting layer (functional layer), 32 ... hole injection layer (functional layer), 50 ... common electrode (cathode), 50a ... electron injection cathode, 50b ... cathode, 70 ... organic electroluminescence element part, 80 ... scanning side drive circuit DESCRIPTION OF SYMBOLS 100 ... Data side drive circuit 101 ... Scan line 102 ... Signal line 103 ... Common power supply line 112 ... Switching TFT (thin film transistor) 113 ... Retention capacity 200 ... Surface light emitting device 201 ... Surface light emitting part 202 ... Outer frame part, 203A, 203B ... Organic electroluminescence element, 205 ... Resistance element, 207 ... Replacement time display part (resistance value change detection means), X ... Pixel area, 1000 ... Image forming apparatus (optical printer), 1100 ... line head (surface emitting device), 1100A ... organic EL element, 1100L ... exposure apparatus, 1120 ... imaging optical element, 1120A ... lens element, 1160 ... photosensitive drum, 1160A ... photosensitive. Surface, 1170 ... rotation axis, 1180 ... developing device, 1210 ... transfer roller, 1220 ... transfer medium, 2050 ... mobile phone, 2051 ... display unit, 2060 ... information processing device, 2061 ... input unit, 2062 ... display unit, 2063 ... Housing, 2070 ... clock, 2071 ... display section.

Claims (6)

A substrate,
A surface light-emitting portion provided on one surface of the substrate and made of an organic electroluminescence element;
An outer frame portion provided on one surface of the substrate and surrounding the surface light emitting portion;
A part of the outer frame part has a resistance value change detection means,
The resistance value change detecting means has a set of organic electroluminescence elements connected in parallel, and a resistance element is connected to one of the anodes of the set of organic electroluminescence elements. Surface emitting device.   The work function of the cathode material of the organic electroluminescence element to which the resistance element is connected is larger than the work function of the cathode material of the organic electroluminescence element to which the resistance element is not connected. Surface light emitting device. A substrate,
A surface light-emitting portion provided on one surface of the substrate and made of an organic electroluminescence element;
An outer frame portion provided on one surface of the substrate and surrounding the surface light emitting portion;
A part of the outer frame part has a resistance value change detection means,
The resistance value change detecting means has a set of organic electroluminescence elements connected in parallel,
A surface light-emitting device, wherein a work function of a cathode material of one of the pair of organic electroluminescence elements is larger than a work function of a cathode material of the other organic electroluminescence element.   The surface light-emitting device according to any one of claims 1 to 3, wherein the set of organic electroluminescence elements provided in the resistance value change detecting means has different emission colors.   An electronic apparatus comprising the surface light-emitting device according to claim 1.   5. The method for driving a surface light-emitting device according to claim 1, wherein the resistance value change detection unit is provided in conjunction with light emission of the organic electroluminescence element of the surface light-emitting unit. A set of organic electroluminescence elements emits light, and after a predetermined time of light emission, the emission brightness of the set of organic electroluminescence elements provided in the resistance value change detecting means is switched. Device driving method.

Images