JP2016058262A - Substrate for el element, el element, lighting device, display device, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for an EL element, which can improve efficiency in extracting light and can decrease influences of heat generation in an EL element.SOLUTION: A substrate 8 for an EL element is used for fabricating an EL element in which a light-emitting structure 5 is disposed, the light-emitting structure including a pair of electrodes at least one of which is a transparent electrode 4, and a light-emitting layer 3 interposed between the electrode pair. The substrate includes a light-transmitting substrate 7 and a prism lens layer that is formed on one surface of the light-transmitting substrate and that suppresses reflection of light on the above surface, the light radiating from the organic EL element. The prism lens layer includes a base part, in which refractive index controlling particles having light-transmitting property and a binder having light-transmitting property are compounded and the refractive index of the base part is set to be higher than a refractive index of the light-transmitting substrate; and a plurality of prisms formed into stripes is disposed extending in at least two intersecting directions in the prism lens layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an EL element substrate, an EL element, an illumination device, a display device, and a liquid crystal display device, and more particularly to a suitable technique for light extraction efficiency.

2. Description of the Related Art Conventionally, for example, EL (Electro-Luminescence) elements are used as light sources and display units such as lighting devices, display devices, and liquid crystal display devices.
The EL element is configured, for example, by providing a light emitting structure in which a light emitting layer containing a fluorescent organic compound is sandwiched between an anode and a cathode on one side of a translucent substrate.
In such a light emitting structure, a direct current voltage is applied between the anode and the cathode, electrons and holes are injected into the light emitting layer and recombined to generate excitons, and the excitons are deactivated. It emits light using the emission of light. For this reason, at least the electrode on the light extraction side of the electrode of the light emitting structure is formed of a transparent electrode, and light from the light emitting layer is emitted to the outside through the transparent electrode and the translucent substrate.

  In such an EL element, when light emitted from the light emitting layer is emitted from the translucent substrate, a part of the light is totally reflected at the interface between the translucent substrate and the transparent electrode. In other words, there is a problem that light quantity loss occurs. In general, the light extraction efficiency of an EL element in which such light loss occurs is about 20%. Therefore, in order to improve the light extraction efficiency, it is most effective to suppress total reflection at the interface between the translucent substrate and the transparent electrode. For example, in Patent Document 1, in an EL element in which an electrode, an EL layer, a high refractive index layer, and a transparent body are arranged in this order, light scattering is performed on the light extraction surface side of each of the high refractive index layer and the transparent body. It has been proposed to provide a functional layer. Moreover, in patent document 2, the organic EL element which has an organic electroluminescent layer provided with the translucent board | substrate, the light emitting layer interposed between an anode and a cathode, and the other surface side of the said translucent board | substrate was provided. There has been proposed a light emitting device including a concavo-convex structure portion that suppresses reflection of light emitted from the organic EL element on the other surface.

JP 2006-286616 A JP2013-12500A

  One of the features of EL lighting is that it generates less heat than conventional incandescent bulbs and fluorescent tubes, but there is some heat generation and the EL element deteriorates due to this heat generation. was there. In addition, the efficiency of extracting light from the light emitting layer is further improved, and further reduction in the amount of heat generation is a problem.

  The present invention has been made in view of the above circumstances, and aims to achieve the object of further improving the light extraction efficiency and reducing the influence of heat generation in the EL element.

An EL element substrate of the present invention is an EL element substrate that forms an EL element in which a light emitting structure having at least one electrode pair made of a transparent electrode and a light emitting layer sandwiched between the electrode pair is disposed. ,
A translucent substrate, and a prism lens layer that is formed on one surface of the translucent substrate and suppresses reflection of light emitted from the organic EL element on the surface;
The prism lens layer includes a base material portion in which a refractive index adjusting particle having light transmittance and a binder having light transmittance are blended to set a refractive index higher than a refractive index of the light transmitting substrate. ,
The prism lens layer is provided with a plurality of stripe-shaped prisms extending at least in the intersecting direction, thereby solving the above problem.
The EL element substrate of the present invention may include a substrate in which a width dimension serving as a heat transfer path is set large as the streaky prism in the prism lens layer.
In the EL element substrate according to the present invention, it is preferable that the streak-like prism having a large width dimension serving as a heat transfer path is periodically provided in the prism lens layer.
The EL element of the present invention is an EL element in which a light emitting structure having at least one electrode pair composed of a transparent electrode and a light emitting layer sandwiched between the electrode pair is disposed,
While comprising the EL element substrate described in any of the above,
In the thickness direction, the transparent electrode, the prism lens layer, and the translucent substrate can be arranged in this order.
In the EL element of the present invention, it is preferable that the light emitting structure forms a plurality of pixels that can be driven independently.
The illuminating device of the present invention preferably includes the EL element described above as an illumination light source.
The display device of the present invention can include the EL element described above as a display unit.
The display device of the present invention can include a pixel display element using liquid crystal and the EL element described above disposed on the back surface of the image display element.
The liquid crystal display device of the present invention can include an image display element using liquid crystal and the illumination device according to claim 6 disposed on the back surface of the image display element.

An EL element substrate of the present invention is an EL element substrate that forms an EL element in which a light emitting structure having at least one electrode pair made of a transparent electrode and a light emitting layer sandwiched between the electrode pair is disposed. ,
A translucent substrate, and a prism lens layer that is formed on one surface of the translucent substrate and suppresses reflection of light emitted from the organic EL element on the surface;
The prism lens layer includes a base material portion in which a refractive index adjusting particle having light transmittance and a binder having light transmittance are blended to set a refractive index higher than a refractive index of the light transmitting substrate. ,
The prism lens layer is provided with a plurality of stripe-shaped prisms extending at least in a crossing direction, whereby the prism lens layer efficiently transmits heat generated from the organic EL element to the outside. Since the light can be emitted, the light extraction efficiency can be further improved and the influence of heat generation in the EL element can be reduced.

  According to the present invention, it is possible to further improve the light extraction efficiency and reduce the influence of heat generation in the EL element.

1 is a schematic cross-sectional view showing a first embodiment of an EL element according to the present invention. It is a schematic cross section which shows the prism lens layer in 1st Embodiment of the EL element which concerns on this invention. It is a schematic plan view which shows the prism lens layer in 1st Embodiment of the EL element which concerns on this invention. It is a schematic cross section which shows 2nd Embodiment of the EL element which concerns on this invention. It is a schematic plan view which shows the prism lens layer in 3rd Embodiment of the EL element which concerns on this invention. It is a schematic cross section which shows the prism lens layer in 4th Embodiment of the EL element which concerns on this invention. 1 is a plan view schematically showing an organic EL display device according to an embodiment of the present invention. It is a top view which shows 5th Embodiment of the illuminating device which concerns on this invention. It is a top view which shows 6th Embodiment of the display apparatus which concerns on this invention. It is a schematic cross section which shows 7th Embodiment of the liquid crystal display device which concerns on this invention.

Hereinafter, a first embodiment of an EL element according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an EL element according to the present embodiment. In the figure, reference numeral 11 denotes an EL element.

  First, the EL element 11 of the present embodiment is provided, for example, in a lighting device as a light emitting means, or in a display device so that the EL element is pixel driven, or disposed on the back surface of an image display element. Used in the display device. Further, in the liquid crystal display device, an illuminating device including the EL element of the present embodiment as a light emitting unit may be arranged on the back surface of the image display element.

FIG. 7 is a plan view schematically showing the organic EL display device according to this embodiment.
As shown in FIG. 7, the organic EL display device includes an organic EL panel DP, a video signal line driver XDR, and a scanning signal line driver YDR. The organic EL panel DP has a plurality of pixels PX provided in a matrix. Each pixel PX includes a red subpixel PXR including an organic EL element OLED that emits red light, a green subpixel PXG that includes an organic EL element OLED that emits green light, and an organic EL that emits blue light. It has a blue subpixel PXB containing the element OLED.

The organic EL panel DP includes an insulating substrate SUB such as a glass substrate. An undercoat layer UC is formed on the substrate SUB.
A channel layer SC is arranged on the undercoat layer UC. Each channel layer SC is, for example, a polysilicon layer including a p-type region and an n-type region. The channel layer SC is covered with the gate insulating film GI. The gate insulating film GI can be formed using, for example, TEOS (tetraethyl orthosilicate).

  On the gate insulating film GI, a scanning signal line SL, a gate electrode G, and the like are formed. Each of the scanning signal lines SL extends in the row direction (first direction X) of the pixel PX, which will be described later, and is arranged in the column direction (second direction Y) of the pixel PX. The scanning signal line SL is made of, for example, MoW. The gate electrode G intersects with the channel layer SC, and these intersecting portions constitute a drive transistor DR. In this example, the drive transistor DR is a top gate type TFT (thin film transistor).

  The gate insulating film GI, the scanning signal line SL, and the gate electrode G are covered with an interlayer insulating film II. A video signal line VL is formed on the interlayer insulating film II. Each video signal line VL extends in the second direction Y and is arranged in the first direction X. The scanning signal line SL and the video signal line VL are connected to the red subpixel PXR, the green subpixel PXG, and the blue subpixel PXB.

  A source electrode SE and a drain electrode DE are further formed on the interlayer insulating film II. The source electrode SE and the drain electrode DE are connected to the source region and the drain region of the channel layer SC through contact holes provided in the interlayer insulating film II and the gate insulating film GI, respectively. The source electrode SE and the drain electrode DE are used for connection between elements included in the pixel PX.

  The video signal line VL, the source electrode SE, and the drain electrode DE are covered with a passivation film. Pixel electrodes (transparent electrodes) 4 are arranged on the passivation film. Each pixel electrode 4 is connected to the drain electrode of the driving transistor DR through a contact hole provided in the passivation film.

  A partition insulating layer is further formed on the passivation film. On the pixel electrode PE, an organic material layer including a light emitting layer is formed as an active layer. The light emitting layer is, for example, a thin film containing a luminescent organic compound whose emission color is red, green, or blue. In addition to the light emitting layer, the organic layer can further include a hole injection layer / hole transport layer, an electron transport layer, an electron injection layer, and the like.

The counter electrode CE is an electrode connected to each other between the pixels PX, that is, a common electrode. In this example, the counter electrode CE is a cathode and a light-transmissive whole surface electrode.
Each organic EL element OLED includes a pixel electrode PE, an organic material layer, and a counter electrode. Each subpixel PXR, PXG, and PXB includes a drive transistor DR, an organic EL element, and the like.

  In this embodiment, the sub-pixels PXR, PXG, and PXB are formed in a stripe shape extending in the second direction Y (a rectangular shape having a major axis in the second direction Y).

  As shown in FIG. 1, the EL element 11 according to this embodiment includes a glass substrate 10, and the counter substrate 1, the light emitting structure 5, and the EL element substrate 8 are laminated in this order from the side opposite to the glass substrate 10. It has the structure made.

The counter substrate 1 is a plate-like or sheet-like member that is disposed to face an EL element substrate 8 to be described later and sandwiches a light emitting structure 5 to be described later between the EL element substrate 8.
The material of the counter substrate 1 has an appropriate mechanical strength and can support the light emitting structure 5. For example, any material can be used as long as it can protect the light emitting structure 5 from moisture and the outside air. It is not limited.

The light emitting structure 5 includes a counter electrode 2 disposed on the counter substrate 1, a transparent electrode 4 disposed on the surface of the EL element substrate 8 facing the counter substrate 1, and between the counter electrode 2 and the transparent electrode 4. And the light emitting layer 3 sandwiched between the layers.
The light emitting structure 5 is one in which the light emitting layer 3 emits EL when a voltage is applied to the transparent electrode 4 and the counter electrode 2 constituting the electrode pair, and various conventionally known structures can be employed.

Although the polarities of the counter electrode 2 and the transparent electrode 4 are not particularly limited, in this embodiment, since the light generated in the light emitting layer 3 is emitted to the EL element substrate 8 side, at least the transparent electrode 4 has good translucency. It is necessary to have an electrode.
Examples of materials suitable for the transparent electrode 4 include, for example, ITO (indium tin oxide), IZO (indium zinc), and the like. When ITO is used as the material of the transparent electrode 4, the transparent electrode 4 is preferably an anode.

As the material of the counter electrode 2, since the presence or absence and the degree of translucency of the counter electrode 2 are not questioned, an appropriate metal material having good conductivity, for example, aluminum, silver, copper, or the like can be used.
In order to increase the light traveling toward the EL element substrate 8, the counter electrode 2 is preferably made of a highly reflective material.

The light emitting layer 3 can be a white light emitting layer, for example. In this case, the transparent electrode 4 is made of ITO and the counter electrode 2 is made of aluminum. From the transparent electrode 4 side toward the counter electrode 2, CuPc (copper phthalocyanine) / α-NPD is doped with 1% rubrene / dinactylanthoselan. A configuration in which perylene 1% doped / Alq 3 / lithium fluoride is laminated in this order can be employed.
However, the configuration of the light emitting layer 3 is not limited to this, and an appropriate material that can set the wavelength of light emitted from the light emitting layer 3 to R (red), G (green), and B (blue) is used. It is possible to adopt any configuration.

The EL element substrate 8 protects the light emitting structure 5 by covering the light emitting structure 5 from the side opposite to the counter substrate 1, and transmits light generated in the light emitting layer 3 and transmitted through the transparent electrode 4 to the outside. It is a translucent plate-shaped member for taking out.
In this embodiment, EL device substrate 8 includes a translucent substrate 7 having a lower refractive index n _T than the refractive index of the transparent electrode 4 is formed by laminating on a transparent substrate 7, the light emitting layer 3 And a prism lens layer 6 disposed in close contact with the surface of the transparent electrode 4 on the opposite side.

  As shown in FIG. 2, the prism lens layer 6 is generated in the light emitting structure 5 by preventing total reflection at the interface with the transparent electrode 4 and total reflection at the interface with the translucent substrate 7. Regarding light, it is a light-transmitting layered portion provided to improve the extraction efficiency from the transparent electrode 4 to the light-transmitting substrate 7. As schematically shown in FIG. 1, the prism lens layer 6 includes a lens layer 6A and an OC layer (overcoat layer) 6B.

  If the prism lens layer 6 is inferior in flatness at the interface with the transparent electrode 4, problems may occur in the electrical characteristics of the transparent electrode 4 or a short circuit between the electrodes may occur. By providing the OC layer 6B, it is possible to reliably prevent such a problem. As a material for forming the OC layer 6B, a resin material close to the refractive index of each of the transparent electrode 4 and the lens layer 6A can be employed. It is particularly preferable to configure the OC layer 6B as the same material as the binder matrix of the lens layer 6A.

The lens layer 6A has a refractive index adjusted to a constant value _nBH by blending a light-transmitting binder and refractive index adjusting particles. The magnitude of the refractive index n _BH is set to an appropriate value at which at least one of the light emitted from the light emitting structure 5 is less likely to be totally reflected at the interface with the transparent electrode 4 and the interface with the translucent substrate 7. . However, if the refractive index n _BH is less than or equal to the refractive index n _T of the translucent substrate 7, total reflection at the interface with the translucent substrate 7 does not occur, but total reflection at the interface with the transparent electrode 4 increases. End up. For this reason, the refractive index n _BH needs to be set to a refractive index higher than at least the refractive index n _T of the translucent substrate 7.

  As shown in FIGS. 2 and 3, the lens layer 6A has a streak-like prism 61 having slopes 61a and 61b having a triangular cross section, and a streak having slopes 62a and 62b having a cross-sectional triangle. The prism 62 extends in two directions, the x direction and the y direction, respectively, and the prism 61 and the prism 62 are crossed.

  When light generated in the light emitting structure 5 is incident on the prism slope, part of the light passes through the prisms 61 and 62 to the light-transmitting substrate 7, and part of the light is reflected and incident on another slope. There is a component that returns in the direction and is reflected by the metal electrode. Among the components that have returned, there is a component that changes its angle at the time of reflection and changes to an angle that can be taken out by entering the prism slope again. For this reason, when the lens layer 6A is not disposed, light that cannot be extracted by total reflection can be extracted by providing the lens layer 6A. That is, it is possible to improve the light extraction efficiency from the light emitting structure 5 by providing the lens layer 6A.

  As shown in FIG. 3, the lens layer 6A has a streak-like prism 63 having slopes 63a and 63b having a cross-sectional triangle having a larger width than the prism 61, and a slope 64a having a cross-sectional triangle. , 64b are arranged in such a manner that the prisms 64, 64b extend in two directions, the x direction and the y direction, respectively, and the pitch of the prisms 63, 64 is larger than that of the prisms 61, 62. Yes. Specifically, the prisms 63 and 64 can be set so as to sandwich the four prisms 61 and 62 therebetween. Of course, the pitch is not limited as long as the pitch of the prisms 63 and 64 is larger than that of the prisms 61 and 62, and can be changed as appropriate. The prisms 63 and 64 having a large width dimension serve as heat transfer paths as will be described later.

The material of the binder and the refractive index adjusting particles contained in the lens layer 6A is adjusted so that the refractive index n _BH of the lens layer 6A is at least higher than the refractive index n _T of the translucent substrate 7. If possible, there is no particular limitation. Examples of suitable materials for the binder include either ionizing radiation curable resins or thermosetting resins. Examples of resin materials include acrylic resins, polyester resins, polycarbonate resins, styrene resins, acrylic / styrene resins. The copolymer resin of these can be mentioned.

  When an ionizing radiation curable resin is selected as the binder and ultraviolet rays are used as the ionizing radiation when curing, it is preferable to add a photopolymerization initiator to the hard coat layer forming coating solution.

As this photopolymerization initiator, a known photopolymerization initiator can be used, but it is preferable to use a material suitable for a material for forming a binder (hereinafter referred to as a binder matrix forming material). As the photopolymerization initiator, for example, benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl methyl ketal, and alkyl ethers thereof can be used.
The amount of the photopolymerization initiator used is preferably from 0.5 to 20 parts by weight, and preferably from 1 to 5 parts by weight, based on the binder matrix forming material.

Examples of materials suitable as refractive index adjusting particles contained in the lens layer 6A include metal oxides such as ZrO ₂ (zirconia), TiO ₂ (titanium oxide), and ZnO ₂ (zinc oxide). be able to. Among them, ZrO ₂ and TiO ₂ are preferable as materials for refractive index adjusting particles in terms of high refractive index, chemical stability, and particle size. In particular, ZrO ₂ is preferable because of low light absorption in the visible region. As the refractive index adjusting particles 6b, one kind of these particles may be used, or two or more kinds may be mixed and used.

  As described above, the lens layer 6A is molded by injection molding, extrusion molding, UV molding, or the like using an ionizing radiation curable resin or a thermosetting resin containing a light-transmitting binder and refractive index adjusting particles. Can be formed. The lens layer 6A in the present embodiment can be molded, for example, by pouring a material into a previously formed mold and solidifying it.

As shown in FIG. 1, the translucent substrate 7 is a plate-shaped or sheet-shaped member that transmits light transmitted through the lens layer 6 </ b> A from the light emitting structure 5 toward the glass substrate 10.
The material of the translucent substrate 7 has a refractive index higher than that of the glass substrate 10 and good transmissivity, and a translucent material can be appropriately employed depending on the heat resistant temperature.
Examples of materials that can be suitably used for the translucent substrate 7 include films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyethersulfone (PES), and polycarbonate (PC). Can do. Further, the translucent substrate 7 may be a glass substrate such as a non-alkali glass substrate or a high refractive index glass substrate, not limited to a plastic substrate.

The glass substrate 10 is bonded to the surface of the translucent substrate 7 opposite to the lens layer 6A via a bonding layer 9 made of a transparent adhesive or adhesive material. As a material of the bonding layer 9, for example, an acrylic adhesive or a pressure-sensitive adhesive can be employed.
Further, when a glass substrate is used as the translucent substrate 7, the glass substrate 10 is preferably not provided.

  In the lens layer 6 </ b> A of the present embodiment, a plurality of prisms 61 to 64 having a streak shape are disposed so as to extend in the xy direction that is at least two directions intersecting each other. Compared to a unidirectional prism structure, heat generation of the EL element itself can be reduced. By making it two directions, heat diffuses and it is possible to release heat to the panel edge. Also, heat generation can be reduced by changing the pitch and depth ratio of the prisms 61 to 64.

  In the lens layer 6A of the present embodiment, the pitch and the ratio in the depth direction of the plurality of prisms 61 to 64 that are in the form of stripes are not constant values but are changed. Specifically, the pitch of the prisms 63 is set to be larger than that of the prisms 61, and at the same time, the width of the prism 63 having a dimension in the depth direction of the prisms 63, that is, a triangular cross-sectional shape, compared to the prisms 61. The size ratio is set to be large.

Similarly, the pitch of the prisms 64 is set to be larger than that of the prisms 62. The depth dimension of the prisms 64 compared to the prisms 62, that is, the prism 64 having a triangular cross-sectional shape has a width dimension ratio of It is set to be large.
In addition, the prisms 61 to 64 are all arranged so as to be separated from the adjacent prisms, and a rectangular region whose outline is formed by the intersecting streak-like prisms 61 to 64 is parallel to the main surface of the substrate. It is a flat state.

Thereby, the surface area of the lens layer 6A can be increased. Thus, by increasing the surface area of the lens layer 6A, it is possible to easily release the heat generated by the light emitting structure 5 in contact (adjacent), and the heat generation as the EL element can be reduced.
In particular, in the lens layer 6A, in the in-plane direction, the prisms 61 to 64 are provided so as to extend in two different directions, so that heat can be easily released in the in-plane direction of the EL element. .

In the EL element 11 of the present embodiment, heat in the depth direction (thickness direction) is difficult to escape, so that the prisms 61 to 64 extend in two different directions so that heat can be easily released to the panel edge. can do. In addition, it is preferable that the dimensions in the depth direction of the prisms 61 to 64 are small in order to maintain the dimensional accuracy during processing.
Furthermore, since the OC layer 6B is easier to stack when the depth dimension in the prisms 61 to 64 is smaller, it is preferable to set the depth dimension in the prisms 61 to 64 as small as possible within a range where the surface area can be increased in a preferable state.

Hereinafter, a second embodiment of an EL element according to the present invention will be described with reference to the drawings.
FIG. 4 is a schematic cross-sectional view showing the EL element 11 in the present embodiment.
This embodiment is different from the first embodiment described above in respect of the glass substrate 10, and other corresponding components are denoted by the same reference numerals and description thereof is omitted.

In this embodiment, as shown in FIG. 4, the translucent board | substrate 7, the glass substrate 10, and the bonding layer 9 are excluded, and it is set as the EL element 11 made flexible.
When the translucent substrate 7 and the glass substrate 10 are removed as in this embodiment, a barrier layer is required, and thus the barrier film 20 is laminated on the outermost surface.

In the present embodiment, the lens layer 6A may be directly formed on the barrier film, or the anchor layer may be laminated, and then the lens layer 6A may be formed.
Examples of the anchor layer include acrylate resins, acrylic acrylate resins, urethane acrylate resins, and the like, and further examples include those added with a silicone coupling agent or silica particles.

Hereinafter, a third embodiment of an EL element according to the present invention will be described with reference to the drawings.
FIG. 5 is a plan view showing the lens layer 6A of the EL element in the present embodiment.
This embodiment is different from the first and second embodiments described above with respect to the arrangement of the prisms, and the corresponding components other than this are given the same reference numerals and description thereof is omitted.

In the lens layer 6A of the present embodiment, prisms 65a to 66c are arranged and intersected in three different directions.
Specifically, the lens layer 6A includes a streak-like prism 65a having a triangular cross section as shown in FIG. 5 and a streak prism 65b having a triangular cross-section as shown in FIG. The stripe-shaped prisms 65c having slopes having a triangular cross section extend in three directions intersecting each other at an angle of 60 °, and the prisms 65a to 65c are arranged in a crossed manner. Yes.

  As shown in FIG. 5, the lens layer 6A of the present embodiment has a stripe-shaped prism 66a having a cross-sectional triangle having a larger width dimension than the prism 65a, and a section having a larger width dimension than the prism 65b. A triangular prism 66b having a triangular shape and a linear prism 66c having a cross-sectional triangle having a larger width dimension than the prism 65c extend in three directions, respectively, and extend more than the prisms 65a to 65c. It arrange | positions so that the pitch of -66c may become large. Specifically, the prisms 66a to 66c can be set so as to sandwich the three prisms 65a to 65c therebetween. Of course, the pitch is not limited as long as the pitch of the prisms 66a to 66c is larger than the pitch of the prisms 65a to 65c, and can be changed as appropriate.

  The lens layer 6A of this embodiment has such an arrangement. Compared with a one-way prism structure or a two-way prism structure, heat generation of the EL element itself can be reduced. Heat is diffused by using three directions, and heat can be released more easily by the panel edge. Moreover, heat generation can be reduced by changing the pitch and depth ratio of the prisms 65a to 66c.

  In the lens layer 6A of the present embodiment, the pitch and the ratio in the depth direction of the plurality of prisms 65a to 66c having a streak shape are not constant values but are changed. Specifically, the pitch of the prisms 66a is set to be larger than that of the prisms 65a, and the depth dimension of the prisms 66a compared to the prisms 65a, that is, the ratio of the width dimensions of the prisms 66a having a triangular cross-sectional shape. It is set to be large.

Similarly, the pitch of the prisms 66b is set to be larger than that of the prisms 65b, and the ratio of the dimension in the depth direction of the prisms 66b, that is, the width dimension of the prisms 66b having a triangular cross-sectional shape is larger than that of the prisms 65b. The pitch of the prism 66c is set to be larger than that of the prism 65c. The depth dimension of the prism 66a compared to the prism 65c, that is, the width dimension of the prism 66c having a triangular cross-sectional shape. The ratio is set to be large.
The prisms 66a to 66c having a large width dimension serve as heat transfer paths in the same manner as the prisms 63 and 64.

Thereby, the surface area of the lens layer 6A can be increased. Thus, by increasing the surface area of the lens layer 6A, it is possible to easily release the heat generated by the light emitting structure 5 that is in contact (adjacent), and the heat generation as an EL element can be reduced.
In particular, in the lens layer 6A, in the in-plane direction, the prisms 65a to 66c are provided so as to extend in three different directions, so that heat can be easily released in the in-plane direction of the EL element. .

In the EL element of the present embodiment, heat in the depth direction (thickness direction) is difficult to escape, so that the prisms 65a to 66c extend in two different directions so that heat can be easily released to the panel edge. be able to. In addition, it is preferable that the dimensions in the depth direction of the prisms 65a to 66c are small in order to maintain the dimensional accuracy during processing.
Furthermore, since the OC layer 6B is easier to stack when the dimension in the depth direction of the prisms 65a to 66c is smaller, it is preferable to set the dimension in the depth direction of the prisms 65a to 66c as small as possible within a range where the surface area can be increased in a preferable state.

  Also in the present embodiment, it is possible to improve the light extraction efficiency from the light emitting structure 5 by providing the lens layer 6A, and to provide an EL element capable of extending the life while suppressing the temperature rise. .

  In the present embodiment, the prisms 66a, 66b, 66c having large width dimensions intersect with each other, and are planar positions that occupy the entire area by a regular hexagon and a regular triangle having one side that is located on one side of the regular hexagon. However, the present invention is not limited to this cross-position relationship as long as necessary thermal conductivity and light extraction efficiency can be maintained.

Hereinafter, 4th Embodiment of the EL element which concerns on this invention is described based on drawing.
FIG. 6 is a plan view showing the lens layer 6A of the EL element in the present embodiment.
This embodiment is different from the first to third embodiments described above in terms of the position where the lens layer 6A is laminated, and other corresponding components are denoted by the same reference numerals and description thereof is omitted. .

  In the prism lens layer 6 of the present embodiment, as shown in FIG. 6, the OC layer 6B is deleted and laminated as the light emitting structure 5, the transparent electrode 4, the translucent substrate 7, and the lens layer 6A.

  In this case, the lens layer 6A is laminated on the translucent substrate 7, and the transparent electrode 4 is laminated directly on the surface opposite to the surface on which the lens layer 6A of the translucent substrate 7 is laminated. In this case, an air layer exists between the bonding layers 9 and the heat dissipation effect can be promoted.

Hereinafter, 5th Embodiment of the illuminating device 70 which concerns on this invention is described based on drawing.
FIG. 8 is a plan view showing the arrangement of the EL elements 11 in the illumination device 70 according to this embodiment.

In the illumination device 70 of this embodiment, a plurality of EL elements 11 having a rectangular shape in plan view are provided adjacent to each other, and a plurality of pixels that can be driven independently by the light emitting structure 5 are formed and provided as an illumination light source. .
A prism lens layer 6 provided with intersecting prisms as shown in FIGS. 3 and 5 is provided on the entire surface of the EL element 11 of the present embodiment, and a plurality of EL elements 11 having this lens layer 6 are arranged. Arranged. The regions where the adjacent lens layers 6 are provided can be separated from each other, or the lens layers 6 can be continuous as a single body, and the independent light emitting structures 5 can be arranged in parallel.

  In particular, when the lens layer 6 is continuously integrated, the prism continues to the edge of the illumination device 70 in the vicinity of the front surface of the illumination device 70, so that waste heat can be efficiently performed. Moreover, the uniformity of the in-plane light emission as the illuminating device 70 can be maintained by continuing the lens layer 6 integrally.

Hereinafter, a sixth embodiment of a display device 71 according to the present invention will be described with reference to the drawings.
FIG. 9 is a plan view showing the arrangement of the EL elements 11 in the present embodiment.

In the display device 71 of the present embodiment, the EL element 11 in which a plurality of pixels that can be driven independently by the light emitting structure 5 is provided as a display unit.
The plurality of light emitting structures 5 are arranged in a plurality of rows and columns, and a prism lens layer 6 in which intersecting prisms as shown in FIG. 3 and FIG. It is provided on the entire surface of the element 11.

  As described above, since the prism lens layer 6 is provided on the entire surface of the EL element 11, in the display device 71, since the prism continues to the edge of the display device 71, a plurality of light emitting structures are provided via the prism. 5 can efficiently waste heat. Further, since the prism lens layer 6 is provided on the entire surface of the EL element 11, the uniformity of in-plane light emission as the display device 71 can be maintained.

Hereinafter, a seventh embodiment of a liquid crystal display device 72 according to the present invention will be described with reference to the drawings.
FIG. 10 is a cross-sectional view showing the arrangement of the EL elements 11 in this embodiment.

  In the present embodiment, the liquid crystal display device 72 includes a liquid crystal panel 73 (image display element) and the EL element 11 of the present embodiment. The liquid crystal panel 73 is an image display element using liquid crystal, and illustration of a detailed configuration is omitted, but various known configurations can be employed. As an example of a configuration suitable for the liquid crystal panel 73, for example, the light transmittance of pixels arranged in a rectangular shape in plan view is controlled, and the polarization state of the liquid crystal layer sandwiched between polarizing plates is controlled independently for each pixel. It is possible to adopt a configuration in which image display is performed by changing the above. In this case, the polarization state of the liquid crystal layer is controlled by applying an electric field corresponding to the image signal by an electrode (not shown) arranged for each pixel.

In this embodiment, the EL element 11 is disposed on the back surface of the liquid crystal panel 73 and is a light emitting means for illuminating the liquid crystal panel 73 from the back surface, and constitutes an illumination device in the liquid crystal display device 72.
For this reason, the EL element 11 only needs to irradiate the liquid crystal panel 73 with uniform illumination light by the lens layer 6. In the present embodiment, a single EL element 11 is provided, but a plurality of light emitting pixels that can emit light independently may be provided. The structure in one light emission pixel is shown.

  As described above, since the prism lens layer 6 is provided on the entire surface of the EL element 11 on the back surface of the liquid crystal panel 73, in the liquid crystal display device 72, the prism continues to the edge of the liquid crystal display device 72. Thus, waste heat can be efficiently generated from the light emitting structure 5. Further, since the prism lens layer 6 is provided on the entire surface of the EL element 11, the uniformity of in-plane light emission as the liquid crystal display device 72 can be maintained.

  Examples according to the present invention will be described below.

(Example 1)
The EL element as Example 1 was manufactured as follows.
A polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., refractive index n _T : 1.60) was used as the translucent substrate 7.
As a binder matrix forming material for the lens layer 6, a UV curable resin (manufactured by ADEKA), a photopolymerization initiator (manufactured by BASF), and a zirconia dispersion (manufactured by Solar Co., Ltd.) as high refractive index fine particles were prepared. These were appropriately blended to form a coating liquid A.
The UV curable resin is cured by exposing the UV light from the PET film side while conveying the sheet coated with the coating liquid A using a cylinder mold cut into a prism shape, and then the PET film is removed from the mold. A structural layer to be the lens layer 6 having a desired shape was produced by releasing the mold.

  Next, an OC layer 6B is laminated on the lens layer 6A with a micro gravure coater, and evaluation is performed as an EL element. Therefore, ITO is formed as the transparent electrode 4 on the OC layer 6B of the obtained EL element substrate 8. Further, the light emitting layer 3 and the counter electrode 2 were formed, and the counter substrate 1 was bonded to obtain an EL element similar to that of the first embodiment.

(Example 2)
Using Example 1 as a reference, an EL element was obtained in the same manner by changing the refractive index n _BH .

(Example 3)
Using Example 1 as a reference, EL elements were similarly obtained by changing the refractive index n _BH and the prism depth (thickness direction dimension).

Example 4
The EL element was obtained in the same manner by changing the prism depth (thickness direction dimension) and the prism pitch with reference to Example 2.

(Comparative Example 1) to (Comparative Example 4)
Similarly, a comparative example was produced.
These details are shown in Table 1.

The coating liquid was set for controlling the refractive index. Cross means that a prismatic prism in two directions is provided.
The depth of the prisms 61 and 62 is “prism depth (small)”, the depth of the prisms 63 and 64 is “prism depth (large)”, and the pitch of the prisms 61 and 62 is “prism pitch (small)”. The pitch of the prisms 63 and 64 is “prism pitch (large)”.

  For these EL elements, the following lens layer extraction efficiency and evaluation tests for heat dissipation were performed. The results are also shown in Table 1.

“Light extraction efficiency” evaluation The light extraction efficiency was evaluated by measuring the total luminous flux when the EL element of each example and each comparative example was caused to emit light and the total luminous flux of the comparative EL element with the lens layer removed, Relative evaluation was performed based on the rate of increase of the luminous flux with respect to the total luminous flux of the EL element for comparison.
Measurement of the total luminous flux was performed using an LMS-400 (trade name: manufactured by labsphere), which is a total luminous flux measuring instrument using an integrating sphere.

  The evaluation results are shown in the (Efficiency) column of Table 1, "◎" when the rate of increase in luminous flux is 20% or more, "○" when 5% or more and less than 20%, and "○" when the rate is less than 5%. It was described as “X”.

"Heat dissipation"
The evaluation of heat dissipation was evaluated by measuring the temperature of the panel surface after causing the EL elements of the examples and comparative examples to emit light and maintaining the lighting state for a predetermined time.

  The evaluation results are shown in the (Heat dissipation) column of Table 1 as “◎” when the heat generation is uniformly reduced on the entire panel surface as compared with the comparative EL panel from which the lens layer is deleted, and “when heat generation is reduced”. “O”, and the case where no change occurs in heat generation was described as “X”.

  From these results, in the EL elements of Examples 1 to 3 in the present invention, it is possible to improve the light extraction effect and reduce the heat generation as compared with the EL elements of Comparative Examples 1 to 4. I know that there is.

    As an application example of the present invention, it is possible to realize thin and non-heated illumination, so that when used in a standlight or the like, it is possible to provide safe illumination that does not cause burns, and there is no uneven brightness due to uneven distribution of heat. High quality lighting can be realized. Moreover, it can be used for various interior lighting due to such characteristics, and also for indoor spaces such as automobiles due to its thin and light characteristics.

DESCRIPTION OF SYMBOLS 1 ... Counter substrate 2 ... Counter electrode 3 ... Light emitting layer 4 ... Transparent electrode 5 ... Light emitting structure 6 ...
6A ... Lens layer 6B ... OC layers 61-64, 65a-66c ... Prism 61a-64b ... Slope 7 ... Translucent substrate 8 ... EL element substrate 9 ... Bonding layer 10 ... Glass substrate 20 ... Barrier layer

Claims (9)

An EL element substrate forming an EL element in which a light emitting structure having an electrode pair of at least one of transparent electrodes and a light emitting layer sandwiched between the electrode pair is disposed,
A translucent substrate, and a prism lens layer that is formed on one surface of the translucent substrate and suppresses reflection of light emitted from the organic EL element on the surface;
The prism lens layer includes a base material portion in which a refractive index adjusting particle having light transmittance and a binder having light transmittance are blended to set a refractive index higher than a refractive index of the light transmitting substrate. ,
The EL element substrate, wherein the prism lens layer is provided with a plurality of stripe-shaped prisms extending at least in a crossing direction.   The EL element substrate according to claim 1, wherein the prism lens layer includes the streak-like prism having a large width dimension to be a heat transfer path.   3. The EL element substrate according to claim 2, wherein in the prism lens layer, the streak-like prisms having a large width dimension to be a heat transfer path are periodically provided. An EL element in which a light emitting structure having at least one electrode pair made of a transparent electrode and a light emitting layer sandwiched between the electrode pair is disposed,
While comprising the EL element substrate according to any one of claims 1 to 3,
An EL element, which is arranged in the thickness direction in the order of the transparent electrode, the prism lens layer, and the translucent substrate.   5. The EL element according to claim 4, wherein the light emitting structure forms a plurality of pixels that can be driven independently.   An illumination device comprising the EL element according to claim 4 as an illumination light source.   A display device comprising the EL element according to claim 4 as a display unit.   A liquid crystal display device comprising: a pixel display element using liquid crystal; and the EL element according to claim 4 disposed on a back surface of the image display element.   A liquid crystal display device comprising: an image display element using liquid crystal; and the illumination device according to claim 6 disposed on a back surface of the image display element.

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