JP2001244067A - Organic electroluminescence light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear organic electroluminescence light source having high brightness. SOLUTION: This edge-emitting organic electroluminescence light source has an organic EL element having at least one light emitting organic layer 104 on a transparent substrate 101 and uses the emitted light 111 emitted from the edge 108 of the above mentioned transparent substrate. By machining the edge flat, it is possible to suppress diffusion and scattering of the light emitted from the edge, thus effectively using the light from the organic electroluminescence element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light source using an organic electroluminescence (hereinafter, EL is abbreviated as EL) element.

[0002]

2. Description of the Related Art An organic thin-film EL device having a laminate in which at least one organic light-emitting layer is interposed between an anode and a cathode can greatly reduce an applied voltage as compared with an inorganic EL device. Therefore, development for obtaining a higher-performance organic EL element is being actively promoted through development and improvement of materials. With respect to the organic thin film EL device, devices having various luminescent colors and devices having high luminance and high efficiency have already been developed, and use as a pixel of a display device and use as a light source are being promoted.

As a conventional technique for reducing the thickness of an illuminating device for illuminating a liquid crystal display element, Japanese Patent Laid-Open No. 10-50124 can be mentioned. This publication discloses a technique using an organic EL element having a linear pattern as a light source of a front light for illuminating the liquid crystal display device from the front or a backlight for illuminating the liquid crystal display device from the back.

[0004]

However, according to the above-mentioned prior art, when the end face of the transparent substrate is not smooth, it is difficult to cause all the light emitted from the organic EL element to enter the display device by scattering the light there. It is difficult, and there is a problem in that the organic EL element is required to emit light more than necessary.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a lighting device (organic EL light source) that can effectively use light emission from an organic EL element.

[0006]

According to the present invention, there is provided an organic EL light source having the following constitution.

(1) At least one organic layer having a light-emitting function is sandwiched between an anode thin film and a cathode thin film on a light-transmitting and light-transmitting transparent substrate, and light is emitted through an end face of the transparent substrate. An organic EL light source, wherein a means for smoothing an end face of the transparent substrate is provided.

[0008] According to the above configuration, diffusion and scattering of light emitted from the end face of the transparent substrate can be suppressed.
Light emission from the organic EL element can be used effectively,
A light source with low power consumption and high luminance can be provided.

(2) The organic EL light source according to (1), wherein an end face of the transparent substrate is processed smoothly by applying a material having transparency.

[0010] According to the above configuration, diffusion and scattering of light emitted from the end face of the transparent substrate can be suppressed.
Light emission from the organic EL element can be used effectively,
A light source with low power consumption and high luminance can be provided. As a material having transparency, a resin material or the like is preferably applied.

(3) The organic EL light source according to the above (1), wherein an end face of the transparent substrate is smoothed by polishing.

According to the above configuration, diffusion and scattering of light emitted from the end face of the transparent substrate can be suppressed.
Light emission from the organic EL element can be used effectively,
A light source with low power consumption and high luminance can be provided.

(4) The organic EL light source according to (1), wherein the end face of the transparent substrate is processed into a smooth convex shape by applying a material having transparency.

According to the above configuration, diffusion and scattering of light emitted from the end face of the transparent substrate can be suppressed.
Light emission from the organic EL element can be used effectively,
A light source with low power consumption and high luminance can be provided. As a material having transparency, a resin material or the like is preferably applied.

(5) In the organic EL device according to any one of the above (1) to (4), it is preferable that the transparent substrate is wound by a light-diffusing reflective member except at least one end face. Characteristic organic EL light source.

According to the above configuration, light emitted from the organic EL element repeats diffusion and reflection in the transparent substrate, and is emitted from the end face of the transparent substrate without loss. Therefore, light emission from the organic EL element can be effectively used, and a light source with low power and high luminance can be provided.

[0017]

Embodiments of the present invention will be described below.

(First Embodiment) FIG. 1A is a plan view showing the structure of an organic EL light source according to a first embodiment of the present invention, and FIG. 1B is a plan view of FIG. FIG. 3 is a cross-sectional view along the line AB. In FIG. 1A, some components are omitted for easy viewing.

In the first embodiment, an anode 102 is formed on a transparent substrate 101 having a light-transmitting and light-guiding outer dimension of 6 mm × 50 mm and a thickness of 0.7 mm, on which at least one layer of light emitting function is provided. After forming an organic layer 103 having a cathode 104 formed thereon, a transparent or translucent sealing substrate 106 is subjected to a sealing process, and one end face 1 of the transparent substrate is further processed.
08, the light diffusive reflection sheet 107 is wound. In addition, the end face 108 of the transparent substrate is processed to be smooth by applying a resin 109 having transparency.

In the present embodiment, a general soda glass is used as a transparent substrate having a light transmitting property and a light guiding property, but other than the above, quartz, multi-component, rare earth element-doped quartz, rare earth element-doped multi-component Glass materials can be used.

The anode is often used as an electrode on the light extraction side, and is not an exception in the present invention. Therefore, transparent or translucent electrodes are preferred. In the present invention, ITO (tin-doped indium oxide) is used as the anode 102, but other materials such as IZO (zinc-doped indium oxide) can be used.

The thickness of the anode is 50 to 500 nm, especially 5
A range from 0 to 300 nm is preferred. The upper limit is not particularly limited. However, if the thickness is too large, transmittance may drop or peeling may occur, and if the thickness is too small, a sufficient effect as an electrode may not be obtained, and the film at the time of manufacturing may not be obtained. There is also a problem in strength and the like.

In general, it is desirable that the organic layer 103 having a light emitting function is separated in function from a hole transport layer, a light emitting layer, and an electron transport layer. In the present embodiment, N, N′-diphenyl-N, N′-dinaphthyl-1,
1'-biphenyl-4,4'-diamine is formed into a thin film having a thickness of 50 nm by vacuum evaporation. A 50 nm thin film of a tris (8-hydroxyquinoline) aluminum complex, which is generally known as an electron transporting luminescent material, is formed on the hole transporting layer by vacuum evaporation. However, the organic material used for the organic layer is not limited to this.

The thickness of the organic layer is not particularly limited, and varies depending on the forming method.
It is desirable that the thickness be about 00 nm, particularly 10 to 300 nm.

Further, for the organic layer having a light emitting function, various film forming methods such as sputtering, spin coating, dipping, and ink jet method can be selected in addition to vacuum deposition, regardless of whether the organic layer is of low molecular weight or high molecular weight.

The cathode 104 may be a conductive material, and in this embodiment, a 200 nm-thick cathode is formed from an alloy in which magnesium and silver are mixed at a ratio of 10: 1 by vacuum evaporation.

The cathode material is not limited to this, and examples thereof include aluminum, calcium, and a binary alloy of aluminum and lithium.

The thickness of the cathode is usually about 1 to 500 nm. In particular, a range of 50 to 300 nm is desirable.

As a material of the sealing substrate 106, a flat and transparent or translucent material can be used. In this embodiment, general soda glass is used. However, the present invention is not limited thereto, and borosilicate glass, aluminosilicate glass, silica glass, quartz, resin, or the like can be used.

Adhesive 1 used for bonding sealing substrate
As 05, it is common to use a polymer adhesive which is transparent or translucent and has a property of hardly permeating moisture or the like. In this embodiment, a photocurable epoxy resin is used. However, this is not a limitation, and a thermosetting epoxy resin or the like can also be used.

As the light diffusive reflection sheet 107, a plastic sheet into which a white pigment such as titanium oxide or zinc oxide has been kneaded, an aluminum plate coated with a white pigment, and the like can be given. In this embodiment, a polyethylene terephthalate sheet into which titanium oxide is kneaded is used.

By winding the light-diffusing reflection sheet, light 110 emitted vertically from the organic EL element can be diffusely reflected and contribute to light emission 111 from the end face of the transparent substrate. Therefore, it is possible to prevent light from leaking to an area other than the end face of the transparent substrate, which is a part that originally emits light, and to improve the luminance of light emitted from the end face of the transparent substrate. That is, light emitted from the organic EL element can be effectively used.

The transparent resin 109 used for processing the end face 108 of the transparent substrate smoothly is not particularly limited as long as it has transparency. Although a photocurable epoxy resin is used in the present embodiment, a thermosetting epoxy resin or an acrylic resin may be used. Also, the bonding method is not particularly limited, and a dipping method or the like can be used instead of using an adhesive.

Although the end face of the transparent substrate is roughened by the cutting step and the breaking step, the processing and processing of the end face of the transparent substrate make it possible to diffuse and scatter the light 111 emitted from the end face of the transparent substrate. Can be suppressed. Therefore, when the organic EL light source according to the present embodiment is disposed on the end face of the light guide plate as a light source for a front light or a backlight of a liquid crystal display device, light emitted from the organic EL element can be introduced into the light guide plate without loss. The required luminance for the EL element can be reduced. That is, power consumption is reduced.

As shown in FIG. 1, the organic EL light source produced in this embodiment can be a high-luminance linear light source because light is emitted only from the end face.

The organic EL element can emit white light by a manufacturing method. Therefore, in this embodiment, it is also possible to obtain a high-luminance white light source. Therefore, it can be used as favorable illumination for a full-color liquid crystal display device or the like.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
It is sectional drawing which shows schematic structure of the organic EL light source of embodiment.

In this embodiment, an anode 102 is formed on a transparent substrate 101 having a light transmitting and light guiding property and having an outer dimension of 6 mm × 50 mm and a thickness of 0.7 mm, and at least one layer of a light emitting function is provided thereon. After forming the organic layer 103 having the above-mentioned structure, and further forming the cathode 104, the transparent or translucent sealing substrate 106 is subjected to a sealing process.
8, the light diffusive reflection sheet 107 is wound. Further, all the constituent materials of the organic EL element in this embodiment are the same as those in the first embodiment.

The end face 201 of the transparent substrate is smoothed by polishing.

By processing the end face of the transparent substrate to be smooth, the diffusion and scattering of the light 202 emitted from the end face of the transparent substrate can be suppressed. Therefore, when the organic EL light source according to the present embodiment is disposed on the end face of the light guide plate as a light source for a front light or a backlight of a liquid crystal display device, light emitted from the organic EL element can be introduced into the light guide plate without loss. The required luminance for the EL element can be reduced. That is, power consumption is reduced.

As shown in FIG. 1, the organic EL light source produced in this embodiment can be a high-luminance linear light source because light is emitted only from the end face.

The organic EL element can emit white light by a manufacturing method. Therefore, in this embodiment, it is also possible to obtain a high-luminance white light source. Therefore, it can be used as favorable illumination for a full-color liquid crystal display device or the like.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention.
It is sectional drawing which shows schematic structure of the organic EL light source of embodiment.

In the third embodiment, an anode 102 is formed on a transparent substrate 101 having a light-transmitting and light-guiding outer dimension of 6 mm × 50 mm and a thickness of 0.7 mm, on which at least one layer of light is emitted. The organic layer 103 having a function is formed, and the cathode 104 is further formed and sealed with a transparent or translucent sealing substrate 106.
08, the light diffusive reflection sheet 107 is wound. The constituent materials of the organic EL element in this embodiment are all the same as those in the first embodiment.

The end face 301 of the transparent substrate is processed into a convex shape by a resin 302 having transparency.

By processing the end face of the transparent substrate into a convex shape, when the organic EL light source in this embodiment is arranged on the end face of the light guide plate as a light source for a front light or a backlight of a liquid crystal display device, the light guide plate is originally used. By refracting the radiated light 303 from the organic EL element that has reached the end face of the transparent substrate at an angle where the light cannot enter, it can be changed to emitted light 304 that can be incident on the light guide plate. Therefore, light emission from the organic EL element can be introduced into the light guide plate without loss, and the required luminance for the organic EL element can be reduced. That is, power consumption is reduced.

As shown in FIG. 3, the organic EL light source produced in this embodiment can be a high-luminance linear light source because light is emitted only from the end face.

The organic EL element can emit white light by a manufacturing method. Therefore, in this embodiment, it is also possible to obtain a high-luminance white light source. Therefore, it can be used as favorable illumination for a full-color liquid crystal display device or the like.

[0049]

As described above, the organic EL of the present invention
The light source is a linear light source using light emitted from the end face of the transparent substrate. By performing processing for smoothing the end face of the transparent substrate, light emitted from the end face, that is, light emission from the organic EL element is effective. This has the effect that it can be used for Therefore, the required luminance of the organic EL element can be reduced, and a light source with low power consumption can be realized. In addition, since the light source is linear, when used as a light source for a backlight or front light of a liquid crystal display device, a conventional LED is used.
Compared with a display device using a point light source or the like, it is possible to display an image that is visually excellent without color and luminance unevenness.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of an organic electroluminescence light source according to a first embodiment of the present invention, wherein FIG. 1 (a) is a plan view, and FIG. 1 (b) is AB in FIG. It is sectional drawing along the line.

FIG. 2 is a cross-sectional view illustrating a structure of an organic electroluminescence light source according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a structure of an organic electroluminescence light source according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Transparent substrate 102 ... Anode 103 ... Emissive organic layer 104 ... Cathode 105 ... Sealant 106 ... Sealing substrate 107 ... Light diffusing reflective sheet 108 ... Transparent substrate end face 109 ... Transparent resin 110 ... Organic EL Emitted light from the element 111 ... Emitted light from the end face 201 ... End face of the transparent substrate 202 ... Emitted light from the end face of the transparent substrate 301 ... End face of the transparent substrate 302 ... Transparent resin 303 ... Emitted light from the organic EL element 304: light emitted from the end face of the transparent substrate

Claims (5)

[Claims] 1. A light-transmitting and light-transmitting transparent substrate having at least one organic layer having a light-emitting function sandwiched between an anode thin film and a cathode thin film, and radiating light through an end face of the transparent substrate. An organic electroluminescent light source, wherein a means for smoothing an end face of the transparent substrate is provided. 2. The organic electroluminescent light source according to claim 1, wherein an end face of said transparent substrate is processed smoothly by applying a material having transparency. 3. The organic electroluminescence light source according to claim 1, wherein an end face of said transparent substrate is smoothed by polishing. 4. The organic electroluminescent light source according to claim 1, wherein an end face of said transparent substrate is processed into a smooth convex shape by applying a material having transparency. 5. The organic electroluminescent device according to claim 1, wherein the transparent substrate is wound around a light-diffusing reflective member leaving at least one end face. Luminescent light source.