JP2008176291A - Organic light-emitting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic light-emitting apparatus which reduces reflection of light made incident to organic light-emitting elements and has high contrast in a bright environment. <P>SOLUTION: The organic light-emitting apparatus has a number of organic light-emitting elements and has contact holes formed for providing electrical connection to the organic light-emitting elements each having a polarizing plate on a light extraction surface side. The organic light-emitting apparatus further has, on the contact holes, an insulating layer which is a light transmissive member, has an opening defining a light-emitting region of the organic light-emitting element and covers an opening of a planarizing layer and a region between adjacent parts of first electrodes, and a light shielding layer formed on the insulating layer so as to cover the opening part in the planarizing layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic light emitting device having an organic EL (abbreviated as EL).

  When an organic light-emitting device having a plurality of organic EL elements (organic light-emitting elements) is driven by an active matrix circuit, for example, it is configured as shown in FIGS.

  A thin film transistor (TFT) 501 for driving an organic light emitting element (pixel) is formed on a glass substrate 500. The TFT 501 includes a source region 510, poly-Si 511, a drain region 512, a gate insulating film 513, a gate electrode 514, an interlayer insulating film 515, and a drain electrode 516.

  An inorganic insulating film 517 is formed on the TFT 501, and an organic planarizing film 518 is formed to planarize the surface.

  A reflective (lower) electrode 520 serving as an anode is formed on the organic planarizing film 518. The reflective electrode 520 is patterned for each pixel, and the reflective electrode 520 and the drain electrode 516 of the TFT 501 are electrically connected through a contact hole 542 formed in the inorganic insulating film 517 and the organic planarizing film 518.

  A pixel separation film 530 is formed between adjacent pixels so as to cover the peripheral edge of the reflective electrode 520.

  A hole transport layer 523, a light emitting layer 522, and an electron transport layer 524 are formed as an organic functional layer 525 on the reflective electrode 520 exposed from the opening of the pixel separation film 530, and a transparent (upper) electrode 521 serving as a cathode is further formed. Is formed.

  In order to protect the organic light emitting element from moisture, a sealing glass substrate 540 is attached to the substrate 500 using a UV curable epoxy resin. An inert gas 541 is filled between the transparent electrode 521 and the sealing glass substrate 540.

  The organic light emitting device having the above configuration has a high reflectance of visible light at the reflective electrode 520, and when light is incident from the outside, part of the light is reflected by the reflective electrode 520 and emitted from the light extraction surface.

  For this reason, the contrast of the organic light emitting device is low and the visibility is not good in an environment where light easily enters the organic light emitting device, for example, under sunlight.

  Therefore, recently, a linear polarizing plate and a retardation film are arranged on the light extraction surface side, and a device has been devised to reduce the emission of reflected light in the organic light emitting device among the light incident from the outside (Patent Document 1). 2 and 3).

  The principle of an example of a configuration in which these disclosed reflected light reduction techniques are used in an organic light emitting device will be described with reference to FIG.

  The organic light emitting device shown in FIG. 5 is formed by laminating a reflective layer 14, a light emitting layer 13, a retardation compensation film 12, and a polarizing layer 11. In FIG. 5, the reflective layer 14 and the light emitting layer 13 are illustrated with a space therebetween for the sake of explanation.

  The polarizing layer 11 is configured to pass only p-wave or s-wave of incident light. The retardation compensation film 12 has a configuration in which a plurality of retardation films (not shown) are laminated, and has a quarter-wave retardation in a wide wavelength range. The polarizing layer 11 and the retardation compensation film 12 are collectively referred to as a circularly polarizing plate (circularly polarizing member).

  That is, the light that has passed through the polarizing layer 11 and the retardation compensation film 12 is converted into circularly polarized light because the phase of the p wave and the s wave is shifted by a quarter wavelength in a wide wavelength range.

  Light 16 emitted from the light emitting layer 13 in the direction of the polarizing layer 11 passes through the polarizing layer 11 and is emitted outside the organic light emitting device.

  On the other hand, the light 19 emitted from the light emitting layer 13 in the direction of the reflective layer 14 is reflected by the reflective layer 14, and the reflected light 15 passes through the light emitting layer 13, the retardation compensation film 12, and the polarizing layer 11, and It is injected outside.

  Thus, both the light 16 and 19 emitted from the light emitting layer 13 can be emitted outside the organic light emitting device. However, since these lights 16 and 19 (15) pass through only the one linearly polarized light component when passing through the polarizing layer 11, the light intensity is attenuated.

  A part of the light 17 incident from the outside of the organic light emitting device becomes reflected light 0 on the surface of the polarizing layer 11. Of the light 17, light that is not reflected by the polarizing layer 11 is converted into circularly polarized light by the polarizing layer 11 and the retardation compensation film 12, and is reflected by the reflective layer 14.

  When the light 17 is reflected by the reflective layer 14, the phase of the light is shifted by a half wavelength, so that the light 18 that has passed through the phase difference compensation film 12 cannot pass through the polarizing layer 11.

  Based on these principles, the reflection of external light by the reflective layer 14 can be reduced to only light 0 reflected from the surface of the polarizing layer 11.

Furthermore, in Patent Document 3, in addition to such a circularly polarizing member, a stray light from the light emitting element is absorbed and a contrast is improved by using a material that absorbs visible light such as a black pigment or a dye as the pixel separation film. (See paragraph [0273].)
JP-A-7-142170 Japanese Patent Laid-Open No. 9-127858 JP 2005-346043 A

  However, reflection by a highly reflective film such as a metal in the organic light emitting device exists not only in the light emitting region but also in a region of an opening (contact hole) formed in, for example, a planarization layer outside the light emitting region.

  Light that enters the organic light-emitting device, reflects an odd number of times in the organic light-emitting device, and reaches the circularly polarizing plate passes through the transparent electrode or the organic functional layer in the light-emitting region and is reflected once by the reflective electrode. In the case (FIG. 6), the conventional configuration is effective. However, for example, the light reflected by the tapered portion formed in the opening of the planarization layer through the transparent electrode or the organic functional layer outside the light emitting region, or the surface roughness of the opening of the TFT or its lead line and the reflecting electrode The scattered light includes light that reaches the circularly polarizing plate after an even number of reflections (FIG. 7). The phase shift of the light reflected even number of times is not a half wavelength but is emitted through the circularly polarizing plate.

  Thus, the light emitted through the polarizing plate decreases the contrast of the organic light emitting device.

  On the other hand, in the display device described in Patent Document 3, an insulator (pixel separation film) using a material that absorbs visible light such as a black pigment or a dye is formed on an opening (contact hole) of an interlayer insulating film. ing. As a result, it is possible to reduce the emission of light that is reflected an even number of times out of the panel to the outside of the panel.

  When a pixel separation film using such a material that absorbs visible light is actually formed on a display device, it is formed by photolithography using a photosensitive resin, and in photolithography, an exposed portion is insoluble. A black matrix is formed by design.

  However, in the photosensitive resin, it is necessary to use a considerable amount of black colorant in order to sufficiently enhance the light blocking property of the black matrix. In addition, since the exposed radiation is absorbed by the colorant, a phenomenon in which the effective intensity of the radiation in the coating film gradually decreases from the surface of the coating film to the bottom (that is, near the substrate surface) inevitably occurs. Arise. Therefore, the curing reaction inside the coating film tends to become insufficient gradually from the surface toward the bottom. As a result, there is a problem that the shape of the formed pattern tends to be an inversely tapered shape or the adhesion to the substrate is lowered. Moreover, the black photosensitive resin also has a problem that a residue is likely to be generated on the unexposed portion of the substrate.

  As described above, when the shape of the pixel separation film is a reverse taper shape or when there is a residue on the lower electrode, the bottom of the reverse taper or the organic compound layer of the organic light emitting element of the residue is cut off, The electrode and the lower electrode are short-circuited. As a result, many pixels where the organic light emitting element does not emit light are generated.

  Therefore, the present invention provides a high-contrast organic light-emitting device that reduces reflection of light incident on an organic light-emitting element while reducing defects in the pixel and the periphery of the pixel that may occur due to a conventional configuration, and in a bright environment. With the goal.

As means for solving the problems of the background art, the organic light-emitting device according to the present invention includes:
A substrate, a plurality of thin film transistors formed on the substrate, a planarization layer formed on the plurality of thin film transistors, and a plurality of organic light emitting elements formed on the planarization layer, An insulating layer having an opening that defines a light emitting region of the organic light emitting element, and a circularly polarizing member disposed on the plurality of organic light emitting elements and on the light shielding layer,
Each organic light emitting element is sequentially connected to the thin film transistor through an opening provided in the planarizing layer in order on the planarizing layer, and is patterned for each organic light emitting element. In an organic light emitting device having a first electrode, an organic compound layer, and a second electrode that is a light transmission electrode,
The insulating layer is a layer covering between the opening of the planarization layer and the adjacent first electrode,
A light-shielding layer covering the opening of the planarizing layer is provided on the insulating layer.

  According to the present invention, since external light is absorbed not by the insulating layer but by the light shielding layer provided thereon, the occurrence of defects in the pixel and the periphery of the pixel, which has been a problem in the conventional configuration, can be reduced.

  Of the light incident on the organic light emitting device from the outside, the light incident on the contact hole region is incident on the light shielding layer formed above the insulating layer covering the contact hole. If the light shielding layer is a light absorbing member, the outside light is absorbed as it is, so that the outside light emitted to the outside can be significantly reduced. In addition, even when the light shielding layer is a light reflecting member, external light reflected by the light shielding layer can be reduced in transmission by the polarizing member.

  Therefore, the emission of external light can be suppressed, and an organic light emitting device with high contrast in a bright environment can be provided.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to this embodiment.
<First Embodiment>
FIG. 1 is a schematic view showing an organic light emitting device according to this embodiment.

  This organic light emitting device has a plurality of organic light emitting elements and a polarizing member (polarizing plate) 341 on the light extraction surface side. An opening (contact hole) for connecting the first electrode (reflecting electrode) 300 of the organic light emitting element and the TFT 200 for driving the organic light emitting element is formed between adjacent organic light emitting elements, that is, outside the light emitting region. Has been. An insulating layer (pixel separation film) 330 made of resin is formed on the opening as a layer covering the opening. The insulating layer 330 has an opening different from the opening (contact hole), and a light emitting region is defined by the opening. In addition, since the insulating layer 330 is a light transmitting member that does not contain a black resin or a pigment, it is possible to reduce defects in the pixel and the periphery of the pixel, such as step breaks and short circuits, which are problems in the conventional configuration. A light shielding layer 340 is formed on the insulating layer 330 to cover the opening.

  Therefore, light incident on the contact hole region among light incident on the organic light emitting device from the outside enters the light shielding layer 340 on the insulating layer 330. If the light shielding layer 340 is a light absorbing member, the outside light is absorbed as it is, so that the outside light emitted to the outside can be remarkably reduced. Further, even when the light shielding layer 340 is a light reflecting member, external light reflected by the light shielding layer 340 can be reduced by the polarizing member 341. This is because the reflection on the light shielding layer 340 corresponds to an odd number of reflections, so that the emission of light can be suppressed.

  Therefore, the insulating layer 330 is preferably flattened at the opening, but may not be flattened. By flattening the insulating layer 330, the light shielding layer 340 formed thereon is formed with flatness, and thus the reflection on the light shielding layer 340 is reflected an odd number of times. Alternatively, even if the insulating layer 330 is not planarized, the light shielding layer 340 formed thereon may be planarized, or the light shielding layer 340 may be a light absorbing member.

  Further, the reflection in the light emitting region corresponds to the odd-numbered reflection shown in FIG. Therefore, the presence of the polarizing plate 341 on the light extraction side makes it possible to suppress the emission of such light, and to provide an organic light-emitting device with high contrast in a bright environment.

  As shown in FIG. 2, the width dimension Lm of the light shielding layer 340 is larger than the width Lc of the opening and smaller than the interval Lp between adjacent organic light emitting elements (pixels) with the opening interposed therebetween. preferable. Of the light incident on the organic light emitting device from the outside, the light incident on the opening can be more reliably reflected on the light shielding layer 340.

  The light shielding layer 340 is preferably formed so as to avoid the tapered portion Lt of the insulating layer 330 existing around the light emitting region. That is, it is preferable that the light shielding layer 340 is not formed on the tapered portion Lt. When the light shielding layer 340 is disposed on the tapered portion Lt of the insulating layer 330, the incident light passes through the light shielding layer 340 disposed on the tapered portion Lt of the insulating layer 330 as in the example illustrated in FIG. It may be reflected even times and exit through the polarizing member.

  A specific configuration of the organic light-emitting device will be described along a manufacturing process.

  A TFT 200 for driving the organic light emitting element is formed on the substrate 101. The substrate 101 may be transparent or opaque, and is an insulating substrate made of a synthetic resin or the like, or a conductive substrate having an insulating film such as a silicon oxide (SiOx) film or a silicon nitride (SiNx) film formed on the surface. Alternatively, a semiconductor substrate may be used. The active layer poly-Si 104 made of polysilicon which is the semiconductor layer of the TFT 200 is not limited to polysilicon, and amorphous silicon, microcrystalline silicon, or the like may be used.

  The TFT 200 is covered with an inorganic insulating layer 109 made of silicon nitride, and further covered with an organic flattening layer 110 made of an acrylic resin in order to flatten the surface. The inorganic insulating layer 109 may be an inorganic insulating layer made of silicon oxynitride, silicon oxide, or the like. The organic planarizing layer 110 may be made of polyimide resin, norbornene resin, fluorine resin, or the like.

  A first electrode (reflection electrode) 300 is formed as an anode in the light emitting region. The first electrode 300 is patterned for each organic light emitting element, and the drain electrode 108 of the first electrode 300 and the TFT 200 is electrically connected through an opening formed in the inorganic insulating layer 109 and the organic planarization layer 110. Yes.

  Note that although chromium is used for the first electrode 300, a silver film, a silver film containing an additive, an aluminum film, an aluminum film containing an additive, or an aluminum alloy film may be used.

  Further, on the first electrode 300, in order to improve the carrier injection property to the organic compound layer 310, an electrode having a high work function, for example, oxidation of ITO (indium tin oxide) or IZO (indium zinc oxide) is performed. An object transparent conductive layer may be further formed.

  Furthermore, the drain electrode 108 of the first electrode 300 and the TFT 200 may be directly connected, or may be connected via a metal such as an aluminum film or an oxide conductive film such as ITO.

  An insulating layer (pixel separation film) 330 that is a resin film is formed as a layer covering the opening so as to cover the peripheral edge of the first electrode 300 and cover the opening provided between adjacent pixels. For the insulating layer 330, an acrylic resin, a polyimide resin, a novolac resin, or the like may be used.

  An organic compound layer 310 and a second electrode (transparent electrode) 320 to be a cathode are formed on the first electrode 300 exposed from the opening of the insulating layer 330. The organic compound layer 310 is composed of, for example, three layers of a hole transport layer, a light emitting layer, and an electron transport layer, but only the light emitting layer may be used. Or you may be comprised from several layers, such as 2 layers and 4 layers.

  For the hole transport layer, for example, electron donating FL03 is used, but other materials may be used.

The light emitting layer is formed for each light emitting color and is separately applied with a metal mask. For example, CBP doped with Ir (piq) ₃ as a red light emitting layer, Alq ₃ doped with coumarin as a green light emitting layer, and B-Alq ₃ doped with perylene as a blue light emitting layer are used. Other materials may be used.

  For the electron transport layer, for example, electron-accepting Bathophane tropline is used, but other materials may be used.

  The materials of the hole transport layer, the light emitting layer, and the electron injection layer forming the organic compound layer 310 are shown in <Chemical Formula 1>.

  The second electrode 320 is a light transmissive electrode. Although IZO is used, a transparent electrode using an oxide transparent conductive layer such as ITO or a semi-transmissive electrode using a metal semi-transmissive layer such as silver, aluminum, or gold may be used.

  A light shielding layer 340 is formed above the insulating layer 330, on the second electrode 320 formed on the insulating layer 330 in FIG. The light shielding layer 340 is made of aluminum, but may be another metal or a material obtained by adding an additive to aluminum or another metal. The light shielding layer 340 is formed by a vapor deposition method and is applied with a metal mask. However, the light shielding layer 340 may be formed by CVD, or may be applied separately by photolithography or the like.

  At this time, as described above, the width dimension Lm of the light shielding layer 340 is preferably larger than the opening width Lc of the contact hole and smaller than the interval Lp between adjacent pixels. In addition, the light shielding layer 340 is more preferably formed excluding the tapered portion Lt of the insulating layer 330.

  The light shielding layer 340 is formed on the second electrode 320, but may be formed on the insulating layer 330. In short, the light shielding layer 340 may be formed so as to cover the opening of the planarization layer.

  The light shielding layer 340 shown in FIG. 2 is continuously formed across a plurality of openings, but may be formed independently corresponding to each opening. Also, a plurality of openings formed continuously across a plurality of (for example, three, six, etc.) openings may be formed.

  Note that in the case where the second electrode 320 is a common electrode formed continuously across the pixels and the light shielding layer 340 is a conductive member, the light shielding layer 340 is in contact with the second electrode. It may be formed. As a result, it can serve as an auxiliary wiring that assists the electrical conduction of the second electrode 320. In this case, it is preferable that the light shielding layer 340 is continuously formed across the openings of the plurality of planarization layers.

  In order to prevent deterioration due to moisture from the outside, the sealing glass substrate 401 is attached to the substrate 101 with a UV curable epoxy resin in a nitrogen atmosphere having a dew point of −60 ° C. or less, and the sealing glass substrate 401 is filled with dry nitrogen 402. . At this time, it is preferable that a moisture absorption layer such as strontium oxide or calcium oxide is formed on the organic light emitting element side of the sealing glass substrate 401. Note that in this structure, sealing is performed by the sealing glass substrate 401, but sealing may be performed by an inorganic insulating layer made of silicon nitride, silicon oxynitride, silicon oxide, or the like.

  A polarizing member (polarizing plate) 341 made of a retardation compensation film and a polarizing film is attached to the sealing glass substrate 401 with an adhesive material. The retardation compensation film and the polarizing film may be bonded together with an adhesive material.

  The organic light emitting device according to the present invention can be applied to display portions of various electric appliances. For example, a display unit of a television receiver, a display unit of a computer, a display unit of a mobile phone, a display unit of a personal digital assistant (PDA), a display unit of a music playback device, a display unit of a car navigation system, an electronic viewfinder unit of an imaging device And can be applied to lighting equipment.

It is sectional drawing which represented typically the organic light-emitting device which concerns on the 1st Embodiment of this invention. (A) is the top view which represented typically the positional relationship of the light shielding layer. (B) is sectional drawing which represented the positional relationship of the light shielding layer typically. It is sectional drawing which represented typically the organic light-emitting device driven by the conventional active matrix circuit. It is sectional drawing which represented the organic compound layer typically. It is a figure explaining the principle which reduces reflection using a polarizing member. It is a figure showing a mode that incident light reflected an odd number of times. It is a figure showing a mode that incident light reflected even number of times. It is a figure showing a mode that incident light reflects even number of times when the light-reflective light shielding layer is arrange | positioned on the taper part of an insulating layer.

Explanation of symbols

0 Light reflected by the polarizing layer 11 Polarizing layer 12 Phase difference compensation film 13 Light emitting layer 14 Reflecting layer 15 Light emitted from the light emitting layer to the reflecting layer and reflected by the reflecting layer 16 Light emitted from the light emitting layer to the polarizing layer Light 17 Light incident from outside the organic light emitting device 18 Light incident from outside the organic light emitting device and reflected by the reflective layer 19 Light emitted from the light emitting layer to the reflective layer 101 Glass substrate 102 Source region 103 Drain region 104 poly- Si
105 Gate electrode 106 Gate insulating layer 107 Interlayer insulating layer 108 Drain electrode 109 Inorganic insulating layer 110 Organic planarization layer 200 Thin film transistor (TFT)
300 First electrode 310 Organic compound layer 320 Second electrode 330 Insulating layer 340 Light shielding layer 341 Polarizing member 401 Sealing glass substrate 402 Dry nitrogen 500 Glass substrate 501 Thin film transistor (TFT)
510 Source region 511 poly-Si
512 Drain region 514 Gate electrode 513 Gate insulating film 515 Interlayer insulating film 516 Drain electrode 517 Inorganic insulating film 518 Organic planarization film 520 Reflective electrode (lower electrode)
521 Transparent electrode (upper electrode)
522 Light emitting layer 523 Hole transport layer 524 Electron transport layer 525 Organic functional layer 530 Pixel separation film 540 Sealing glass substrate 541 Inactive gas 542 Contact hole 543 Incident light

Claims (5)

A substrate, a plurality of thin film transistors formed on the substrate, a planarization layer formed on the plurality of thin film transistors, and a plurality of organic light emitting elements formed on the planarization layer, An insulating layer having an opening that defines a light emitting region of the organic light emitting element, and a circularly polarizing member disposed on the plurality of organic light emitting elements and on the light shielding layer,
Each organic light emitting element is sequentially connected to the thin film transistor through an opening provided in the planarizing layer in order on the planarizing layer, and is patterned for each organic light emitting element. In an organic light emitting device having a first electrode, an organic compound layer, and a second electrode that is a light transmission electrode,
The insulating layer is a layer covering between the opening of the planarization layer and the adjacent first electrode,
An organic light emitting device comprising: a light shielding layer that covers an opening of the planarizing layer on the insulating layer. The second electrode is an electrode formed continuously across the plurality of organic light emitting elements,
2. The organic light emitting device according to claim 1, wherein the light shielding layer is a conductive member, is in contact with the second electrode, and is an auxiliary wiring that assists electrical conduction of the second electrode.   The organic light-emitting device according to claim 1, wherein the light shielding layer is a layer that is continuously formed across the openings of the planarization layer.   4. The organic light emitting device according to claim 1, wherein the light shielding layer is not formed in a tapered portion formed by the insulating layer around the organic light emitting element. 5. apparatus. The light shielding layer is a layer formed continuously across the opening of the planarization layer,
5. The organic material according to claim 1, wherein a width of the light shielding layer is larger than a width of the opening portion of the planarizing layer and smaller than an interval between adjacent organic light emitting elements. Light emitting device.

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