JP2012089240A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device that can suppress deterioration of a luminescent material so as to obtain the expected emission lifetime.SOLUTION: A lighting panel 100 has an opening 14 penetrating through the panel formed in a light-emitting region 7, so that heat release from the opening 14 enables higher heat dissipation effect than a conventional lighting device (panel). Moreover, because the opening 14 is formed in the neighborhood of a center part apt to be filled with heat, the heat in the region apt to be at a high temperature can be dissipated effectively. Therefore, deterioration of a luminescent material used in a luminous layer can be suppressed (reduced) effectively. Thus a lighting device 110 that obtains the expected emission lifetime can be provided.

Description

  The present invention relates to a lighting device using a solid light source such as an organic EL (Electro Luminescence) as a light source.

Since the organic EL having self-luminous property can have a simpler structure than a liquid crystal display device that requires another light source such as a backlight, application to the display device is being promoted.
Further, taking advantage of the self-luminous property, an application as a light source (light-emitting layer) of an illumination device for indoor lighting has been proposed.

For example, Patent Document 1 discloses an illumination device using an organic EL layer as a light source. Fig.5 (a) is a front view of the illumination panel provided with the organic electroluminescent layer used for the said illuminating device, (b) has shown the sectional side view in the ff cross section of (a).
The illumination panel 90 has a configuration in which a functional layer 67 including an organic EL layer is sandwiched between the element substrate 71 and the sealing substrate 78, and emits light emitted from the organic EL layer from the back surface 71 a of the element substrate 71. The bottom emission type panel configuration was emitted.
Further, according to this document, the anode electrodes 66 a to 66 c that are paired with the reflective cathode electrode 79 formed on the substantially entire surface of the sealing substrate 78 are formed in an annular shape through the organic EL layer. The luminance unevenness can be reduced as compared with the case where the anode electrode is formed in a solid shape.

JP 2007-173520 A

However, the conventional illumination device (illumination panel 90) represented by Patent Document 1 has a problem that the light emitting material of the organic EL layer is deteriorated due to heat generation.
Specifically, the heat generated by the light emission of the functional layer 67 (organic EL layer) is generated from the outside of the peripheral portion of the illumination panel 90, the back surface 71a of the element substrate 71, the surface of the sealing substrate 78, and the external structure. Although heat is radiated from the portion in contact with the surface, it is difficult to say that a sufficient heat radiating effect is obtained. In particular, in the center portion of the panel (around the anode electrode 66a), the heat escape is scarce and heat is easily trapped, and the temperature may exceed the allowable temperature of the light emitting material, which causes deterioration of the light emitting material. It was.
Further, it has been found that this phenomenon becomes more prominent as the size of the lighting panel 90 increases and the lighting time increases.
That is, in the conventional lighting device, the light emitting material is deteriorated, and thus there is a problem that it is difficult to ensure a desired light emission lifetime.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
An illumination device according to this application example includes at least a substrate and a functional layer including a light emitting layer formed on the substrate, and an opening that penetrates the substrate in a light emitting region in which the functional layer is formed in a plane. Is formed.

According to this application example, since the opening that penetrates the substrate is formed in the light emitting region, the heat dissipation effect can be enhanced by heat dissipation from the opening compared to the conventional lighting device (panel). .
Therefore, deterioration of the light emitting material used for the light emitting layer can be suppressed (reduced).
Therefore, it is possible to provide an illumination device that ensures a desired light emission lifetime.

[Application Example 2]
According to the illumination device according to this application example, it is preferable that the opening is formed in a portion including the center in the light emitting region.

According to this application example, since the opening is formed in the vicinity of the central portion where heat is likely to be trapped, it is possible to effectively dissipate the region that is likely to become high temperature.
Therefore, deterioration of the light emitting material can be reduced more effectively.

[Application Example 3]
According to the lighting device according to this application example, it is preferable that a plurality of openings are formed.

  According to this application example, since it is possible to selectively form openings in a portion where a plurality of heat is likely to be trapped, more efficient heat dissipation can be performed. For example, it is suitable for a large lighting panel having a diagonal of 20 inches or more.

[Application Example 4]
According to the illumination device according to this application example, it is preferable that the light emitting layer is an organic EL layer and further includes a sealing layer made of an inorganic material that covers the functional layer.

FIG. 2 is a plan view of the lighting device according to the first embodiment. The sectional side view in the PP cross section of FIG. The enlarged view of the Q section in FIG. The top view of the illuminating device which concerns on Embodiment 2. FIG. (A); Front view of the conventional illumination panel, (b); Side sectional view in the ff section of (a).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

(Embodiment 1)
FIG. 1 is a plan view of the lighting apparatus according to Embodiment 1, and corresponds to FIG. FIG. 2 is a side sectional view taken along the line PP in FIG. 1 and corresponds to FIG.
First, a schematic configuration of the illumination device 110 according to the first embodiment will be described with reference to FIGS.

"Outline of lighting equipment"
The illumination device 110 includes the illumination panel 100, the power supply unit 25, the light control unit 20, and the like. The illumination panel 100 has a configuration in which a functional layer 17 including an organic EL layer is sandwiched between the element substrate 1 and the sealing substrate 18, and substantially white light emitted from the back surface 1 a of the element substrate 1. The bottom emission type panel configuration that emits light is adopted.
Here, the illumination panel 100 has an opening 14 (through hole) formed at substantially the center thereof. This characteristic configuration realizes heat dissipation superior to that of a conventional lighting device.
Hereinafter, the configuration of the illumination panel 100 including the opening 14 will be described in detail.

"Planar structure of lighting panel"
As shown in FIG. 1, the outer shape of the lighting panel 100 is a horizontally long substantially rectangular shape. In each figure including FIG. 1, the horizontal direction in the horizontally long rectangle is defined as the X-axis direction, and the vertical direction shorter than the horizontal direction is defined as the Y-axis direction. In the following description, the opening 14 is the base point, the Y axis (+) side is the upper side, the (−) side is the lower side, the X axis (+) side is the right side, and the (−) side is the left side.
The illumination panel 100 includes a horizontally-long rectangular element substrate 1 that defines its outer shape, and a sealing substrate 18 that is slightly smaller than the element substrate 1. For this reason, an extended region in which each side of the element substrate 1 extends from the sealing substrate 18 is formed around the sealing substrate 18.
A plurality of terminals 30 to 32 for supplying power to the plurality of anode electrodes are formed in the overhang region on one side (upper side) on the upper side of the illumination panel 100. Further, a terminal 35 for supplying electric power to the cathode electrode is formed in the overhanging region on the lower side.

The element substrate 1 as a substrate is a rectangular flat member, and is made of a material transparent to the wavelength of light emitted from the organic EL layer, such as transparent inorganic glass. In the present embodiment, alkali-free glass is used as a suitable example.
Here, the substantially central portion of the element substrate 1 is an opening 14, and a plurality of anode electrodes 6 a to 6 c are formed in an annular shape on the outer periphery thereof with a certain gap therebetween.
The anode 6a formed on the innermost periphery has a hollow rectangle in which an opening that is slightly larger than the opening 14 is formed. The anode electrode 6a is connected to a wiring extending from the upper side to the terminal 30.
The anode electrode 6b is an annular wiring formed along the shape of the anode electrode 6a with a certain gap from the outer periphery of the anode electrode 6a including the wiring. Moreover, the both ends are each connected to the terminal 31a.

The anode electrode 6c formed on the outermost periphery is an annular wiring formed along the shape of the anode electrode 6b with a certain gap from the outer periphery of the anode electrode 6b. Moreover, the both ends are each connected to the terminal 32b.
Here, in this embodiment, a horizontally long rectangular region defined by the outermost shape of the anode electrode 6 c is used as the light emitting region 7. The light emitting region 7 is approximately the same size as the region where the functional layer 17 is formed in a plan view.
In the present embodiment, the number of annular anode electrodes is three (divided) as a preferred example, but the number is not limited to this, and the number is arbitrary, and the size of the lighting panel 100 and the light emission What is necessary is just to set suitably considering quantity.
Further, the cathode electrode 9 is a reflective electrode that is slightly larger than the anode electrode 6c (light emitting region 7) in plan view, and the lower side thereof and the terminal 35 are electrically connected.

"Cross-sectional structure of lighting panel"
FIG. 3 is an enlarged view of a portion Q in FIG.
Next, the cross-sectional configuration of the illumination panel will be described in detail with reference to FIGS.
As shown in FIG. 2, the lighting panel 100 includes an anode electrode 6, a functional layer 17, a filler 13, a sealing substrate 18, and the like formed (laminated) on the element substrate 1.
The anode electrode 6 is a transparent electrode formed on the element substrate 1, and ITO (Indium Tin Oxide) is used as a suitable example. Any conductive transparent electrode may be used. For example, ZnO (Zinc oxide) may be used.

As shown in FIG. 3, the functional layer 17 includes an organic EL layer 8 as a light emitting layer, a cathode electrode 9, an electrode protective layer 10, a buffer layer 11, a gas barrier layer 12 as a sealing layer, and the like.
The organic EL layer 8 is formed so as to cover the anode electrode 6a. In addition, in FIG. 3, it is configured as a single layer as shown by a solid line, but actually, as shown by a broken line, each is composed of a hole transport layer made of an organic thin film, a light emitting layer, an electron injection layer, etc. They are laminated in this order on the anode electrode 6a.

The hole transport layer is made of a sublimable material such as aromatic diamine (TPAB2Me-TPD, α-NPD).
As a suitable example, the light emitting layer has a multilayer structure including a red light emitting layer, a green light emitting layer, and a blue light emitting layer. Note that the present invention is not limited to this configuration, and any structure and material including a plurality of light emitting layers capable of synthesizing substantially white light may be used.
For example, a laminated structure including two layers of an orange light emitting layer and a blue light emitting layer may be employed, or a structure in which an intermediate layer is interposed between the light emitting layers may be employed. Alternatively, a configuration in which an intermediate charge generation layer is interposed between the light emitting layers, that is, a so-called tandem organic EL layer configuration may be used.
The electron injection layer is made of LiF (lithium fluoride) or the like.
Moreover, each layer which comprises the organic EL layer 8 is formed by laminating | stacking a sublimation material using vapor deposition methods, such as a vacuum vapor deposition method, as a suitable example. Note that the present invention is not limited to this method. For example, a coating method in which a polymer material is coated by an ink jet method to form a light emitting layer may be used.
Further, the present invention is not limited to the organic EL, and any solid light source (light emitting layer) that can be formed between the anode electrode 6 and the cathode electrode 9 may be used. For example, an inorganic EL or LED (Light Emitting Diode) is used. May be.

The cathode electrode 9 is a metal layer made of a reflective metal formed so as to cover the organic EL layer 8. In the present embodiment, aluminum is used as a suitable example from the viewpoints of conductivity, reflectance, cost, and the like. Note that the alloy is not limited to aluminum, and an alloy such as aluminum lithium (Al: Li) or magnesium silver (Mg: Ag) may be used. A part of the end faces the element substrate 1 and is connected to the terminal 35 as described above.
The electrode protective layer 10 is made of a transparent and high-density material such as SiO ₂ , Si ₃ N ₄ , or SiOxNy that has a function of blocking moisture.
The buffer layer 11 is a transparent organic buffer layer such as a thermosetting epoxy resin.
The gas barrier layer 12 is a sealing layer made of an inorganic material having a function of blocking moisture, such as SiO ₂ , Si ₃ N ₄ , and SiOxNy, and has a function of blocking moisture. Responsible for preventing intrusion.
The filler 13 is a transparent adhesive layer made of, for example, a thermosetting epoxy resin, and fills the space between the gas barrier layer 12 and the sealing substrate 18 and bonds them together. Further, it also functions to prevent moisture from entering the organic EL layer 8 from the outside.

As a preferred example, the sealing substrate 18 uses the same inorganic glass as that of the element substrate 1. Further, since transparency is not required, a metal substrate may be used.
In the present embodiment, in order to enhance the gas barrier property (particularly moisture), the gas barrier layer 12 is formed and further sealed with the sealing substrate 18. An omitted configuration may be used. In other words, the configuration is not limited to the configuration using two glass substrates, and the configuration may be that of only one glass substrate (element substrate 1). In this case, the sealing substrate 18 is not provided, and the cathode electrode 9 and the gas barrier layer 12 are made thicker than when the sealing substrate 18 is used. A gas barrier property equivalent to that when a single glass substrate is used can be secured.

  Further, the sealing substrate 18 and the element substrate 1 are bonded and sealed by a sealing agent 15 b formed (applied) along the periphery of the opening 14. As the sealant 15, an epoxy adhesive, an ultraviolet curable resin, or the like is used. As shown in FIG. 2, the sealing substrate 18 and the element substrate 1 are bonded and sealed by the sealing agent 15a formed (applied) along the outer shape of the sealing substrate 18 also on the outer periphery of the lighting panel 100. It has been stopped.

The configuration of the lighting panel 100 is not limited to the bottom emission type, and may be a top emission type. In the case of the top emission type, since illumination light is emitted from the sealing substrate 18 side, it is necessary to reverse the top and bottom of the panel.
In addition, a reflective layer is provided below the anode electrode 6 (on the element substrate 1 side), and the thickness of the metal layer constituting the cathode electrode 9 is reduced until light transmittance is obtained.

"Method for forming openings"
Then, the formation method of the opening part 14 is demonstrated using FIG.
As a method for forming the opening 14, an etching method or a method using a laser is suitable. Or you may use these together.
In the case of the etching method, etching is performed using hydrofluoric acid (hydrofluoric acid) as an etching solution (aqueous solution) in a state where portions other than the opening 14 of the lighting panel 100 are masked with a resist or a masking tape. As a preferred example, etching is performed in a state in which the concentration of hydrofluoric acid is within a range of 10 to 50 wt%, the temperature is controlled within a range of 20 ± 10 ° C. with a central value of 25 ° C.

In the case of the laser method, the element substrate 1 and the sealing substrate 18 are cut by irradiating carbon dioxide laser (CO ₂ ) light along the shape of the opening 14. As a preferred example, first, an opening is formed by irradiating the thin sealing substrate 18 with a laser, and then the illumination panel 100 is turned over and the element substrate 1 is irradiated with a laser to penetrate the opening 14. Laser irradiation conditions vary depending on the thickness of the substrate and the performance of the laser irradiation apparatus used. The laser irradiation apparatus is preferably an apparatus capable of setting irradiation conditions such as continuous oscillation and pulse oscillation, irradiation intensity, and the like.
Further, as a pretreatment for laser irradiation, it is preferable to previously form a scribe line (cutting guide groove) along the shape of the opening 14 on the surface of each substrate. The width and depth of the scribe line are determined within a range of several μm to 100 μm according to the thickness of the substrate, and are preferably formed using a photolithography method. It may be formed by machining.

Moreover, although the case where the opening part 14 was formed in the state by which the illumination panel 100 was substantially completed was demonstrated so far, it is not limited to this timing.
For example, the opening 14 may be formed in a state where the element substrate 1 and the sealing substrate 18 are single items. Alternatively, in the manufacturing process, the opening 14 may be formed in a state of a large-sized substrate (panel) that is faced in a state where the plurality of lighting panels 100 are substantially completed (before separation into a single product panel).

"Driving method of lighting panel"
Next, a method for driving the illumination panel 100 will be described with reference to FIG.
Driving power is supplied to the illumination panel 100 from the power supply unit 25 and the light control unit 20.
The power supply unit 25 is a DC power supply. Since the illumination device 110 is assumed to be used for indoor lighting in a residence or a company, a stabilized power source is used as a suitable example. Specifically, a stabilized power source including an AC power source and a stabilized power circuit using a rectifier circuit, a smoothing capacitor, and a series regulator or a switching regulator is used.

The dimmer 20 includes three switches S1 to S3, a controller 21, and the like.
The switch S1 is a switch for turning on / off the supply of a positive potential to the terminal 30, and turns on / off the organic EL layer 8 overlapping the anode electrode 6a.
The switch S2 is a switch for turning on / off the supply of the positive potential to the two terminals 31a, and turns on / off the organic EL layer 8 overlapping the anode electrode 6b.
The switch S3 is a switch for turning on / off the supply of a positive potential to the terminal 32b, and turns on / off the organic EL layer 8 overlapping the anode electrode 6c. As switches S1 to S3, analog switches using MOS transistors, bipolar transistors, or the like are used as suitable examples.
The control unit 21 is a control circuit that controls ON / OFF of the switches S1 to S3, and a MCU (Micro Control Unit) is used as a preferable example.

As described above, according to the illumination device 110 according to the present embodiment, the following effects can be obtained.
Since the opening 14 penetrating the illumination panel 100 is formed in the light emitting region 7, the heat dissipation effect can be enhanced by heat dissipation from the opening 14 as compared with the conventional lighting device (panel).
Furthermore, since the opening 14 is formed in the vicinity of the central portion where heat is likely to be trapped, it is possible to effectively dissipate the region that is likely to become hot.
Therefore, deterioration of the light emitting material used for the light emitting layer (organic EL layer 8) can be effectively suppressed (reduced).
Accordingly, it is possible to provide the lighting device 110 that ensures a desired light emission lifetime.

  In addition, when the lighting panel 100 is configured with only one glass substrate (element substrate 1), the processing of the sealing substrate 18 is not necessary, and thus the opening 14 is more than the configuration using two substrates. Can be easily formed. Further, since it is not necessary to join the two substrates, the sealing agent 15 is not necessary, and the members (the sealing substrate 18 and the sealing agent 15) and the number of steps can be reduced.

(Embodiment 2)
FIG. 4 is a plan view of the lighting apparatus according to the second embodiment, and corresponds to FIG.
The illumination device 210 according to the present embodiment will be described with reference to FIG. In addition, about the component same as Embodiment 1, the same number is used and the overlapping description is abbreviate | omitted.

"Outline of lighting equipment"
The illumination device 210 includes an illumination panel 200, a power supply unit 25, and the like.
In the lighting device 210 of the present embodiment, the light control unit 20 of the first embodiment is omitted.
In addition, the illumination panel 200 according to the first embodiment is such that the outer shape of the illumination panel 200 is substantially circular and that five openings including the opening 24 formed at the approximate center of the light emitting region 47 are formed. Different from 100.
Hereinafter, the difference from the first embodiment will be mainly described.

The illumination panel 200 includes a substantially circular element substrate 41 that defines its outer shape, and a sealing substrate 48 that is slightly smaller than the element substrate 41. For this reason, a projecting region in which the outer shape of the element substrate 41 projects from the sealing substrate 48 is formed around the sealing substrate 48.
In the overhang region, four terminals are formed with the terminal 33a on the upper left side, the terminal 33b on the upper right side, the terminal 33c on the lower right side, and the terminal 33d on the lower left side with respect to the center of the opening 24. The four terminals 33a to 33d are arranged approximately every 90 ° with the center of the opening 24 as a reference. Each of the four terminals 33 a to 33 d is connected to a plus terminal of the power supply unit 25.

Here, the four terminals 33 a to 33 d are connected to one anode electrode 46. In the present embodiment, the anode electrode is not divided, and only one anode electrode 46 is formed on the element substrate 41. For this reason, the light control part 20 (FIG. 1) is omitted.
The anode electrode 46 is formed on substantially the whole area excluding five openings in a portion overlapping the sealing substrate 48 on the element substrate 41 in a plan view. The outer shape (circular shape) of the anode electrode 46 is a light emitting region 47.
The cathode electrode 49 is slightly larger than the anode electrode 46 and is formed so as to cover the anode electrode 46. A terminal 35 connected to the negative terminal of the power supply unit 25 is formed below the cathode electrode 49.

The opening 24 is substantially circular and is formed at the approximate center of the light emitting region 47. In other words, the light emitting region 47 is formed in a portion including the center. The four openings 44 a to 44 d are formed along a substantially concentric circle between the opening 24 and the outer shape of the light emitting region 47.
Here, a gap g is formed between the openings. The dimension of the gap g is set in consideration of the conductive (wiring) resistance of the anode electrode 46 made of ITO formed therebetween.
Specifically, the dimensions are set such that when the lighting panel 200 is turned on, desired luminance can be obtained in the inner regions of the openings 44a to 44d. In other words, the dimension (wiring width) is set so that a large luminance difference due to voltage drop does not occur between the inner and outer regions of the openings 44a to 44d.

Further, the sealing substrate 48 and the element substrate 41 are bonded and sealed by a sealing agent 45 b formed (applied) along the periphery of the opening 24. The same applies to the four openings 44a to 44d. As the sealant 45, an epoxy adhesive, an ultraviolet curable resin, or the like is used.
Note that also on the outer periphery of the illumination panel 200, the sealing substrate 48 and the element substrate 41 are bonded and sealed by a sealing agent 45 a formed (applied) along the outer shape of the sealing substrate 48.

  The configuration of the illumination panel 200 is the same as that of the illumination panel 100 of the first embodiment except for the configuration described above. In the present embodiment, the numbering of the element substrate, the sealing substrate, the opening, the anode electrode, the cathode electrode, the display region, and the like is changed from the numbering in the first embodiment because the planar shape is different. In the cross-sectional view of FIG. 3, the number of each part can be read as the corresponding part. In other words, the cross-sectional structure and manufacturing method of the lighting panel 200 are the same as those described for the lighting panel 100 of the first embodiment.

As described above, according to the illumination device 210 according to the present embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.
According to the lighting panel 200, in addition to the opening 24 formed at the approximate center of the light emitting region 47, the four openings 44a to 44d are also located approximately in the middle between the opening 24 and the outer shape of the light emitting region 47. Is formed.
Thereby, in addition to the central portion of the light emitting region 47 where heat is most likely to be stored during lighting, an opening is also formed in a region where heat is likely to be stored next, so that more efficient heat dissipation can be performed. .
Therefore, deterioration of the light emitting material used for the light emitting layer (organic EL layer 8) can be effectively suppressed (reduced).
Therefore, it is possible to provide the lighting device 210 that ensures a desired light emission lifetime.

  Furthermore, since the four openings 44a to 44d are arranged so as to surround the central opening 24, the four openings serve as design accents, and the merchantability can be improved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification)
This will be described with reference to FIG.
In the second embodiment, the description has been given on the assumption that five openings including the opening 24 are provided. However, the present invention is not limited to this structure, and may be selectively disposed in a portion where heat is likely to be accumulated during lighting. good. Further, any number of openings may be formed as long as it is one or more.
Further, as described above, since the opening serves as a design accent, an opening for the purpose of design only may be provided.

  DESCRIPTION OF SYMBOLS 1,41 ... Element board | substrate as a board | substrate, 8 ... Organic EL layer as a light emitting layer, 12 ... Gas barrier layer as a sealing layer, 17 ... Functional layer, 14, 24, 44 ... Opening part, 7, 47 ... Light emission area | region .

Claims (4)

A substrate,
A functional layer including a light emitting layer formed on the substrate,
An illumination device, wherein an opening penetrating the substrate is formed in a light emitting region in which the functional layer is planarly formed.   The lighting device according to claim 1, wherein the opening is formed in a portion including a center in the light emitting region.   The lighting device according to claim 1, wherein a plurality of the openings are formed. The light emitting layer is an organic EL layer,
The illumination device according to claim 1, further comprising a sealing layer made of an inorganic material that covers the functional layer.

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