JP2006019142A - Light-emitting device and image displaying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device that can prevent from seeing through a background from a view side (or resist seeing through) and suppress the decrease of light quantity radiated as image information to maintain display quality proper, even if a predetermined image information is displayed by using the front side and the back side of a single organic EL panel; and to provide an image displaying device. <P>SOLUTION: An organic EL element applicable to an image displaying device has the configuration that an anode electrode 12 formed with a transparent electrode material between a transparent insulative board 11 and a transparent sealing board 15, which are arranged mutually faced, an organic EL layer 13 formed with a hole transporting layer 13a and an electron transporting luminous layer 13b, and a cathode electrode 14 formed with a (opaque) metallic material are laminated in order; and also has the configuration that a rectangular through hole HLa is formed at the center of the cathode electrode 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting element and an image display device, and more particularly to a light-emitting element and an image display device that are favorable when applied to an electronic device including a plurality of display panels, such as a mobile phone including a main display and a sub-display. .

  In recent years, portable electronic devices such as a mobile phone, a personal digital assistant (PDA), a digital camera, and a music player have been widely used. Among such electronic devices, those provided with a plurality of display panels (displays) for displaying still images, moving images, operation states of the devices, and the like are known.

  FIG. 8 is a schematic configuration diagram illustrating an example of a portable electronic device (mobile phone) including a plurality of displays according to the related art. Here, FIG. 8A is a diagram illustrating the operation surface (inner surface) side of the electronic device, and FIG. 8B is a diagram illustrating the back surface (outer surface) side of the electronic device. FIG. 9 is a schematic cross-sectional view illustrating a configuration example of an image display unit of an electronic apparatus according to the conventional technology.

  As shown in FIGS. 8A and 8B, the mobile phone 200 according to the prior art has a base housing BAS on which operation buttons 230 and the like are arranged, a main display 210 on the operation surface side, and a back surface side. The display unit housing DIS in which the sub display 220 is arranged is configured to be foldable with the hinge unit 240 as a fulcrum.

  Here, for example, as shown in FIG. 9, the main display 210 and the sub-display 220 provided in the display unit housing DIS are respectively connected to the back side (the side opposite to the visual field side) of the individual liquid crystal display devices. A laminated structure arranged so as to face each other (back to back) is applied.

  Specifically, as shown in FIG. 9, the main display 210 includes a light guide plate 216 made of acrylic or the like and a light source 217 so that the field of view is set on the operation surface side (upper drawing) of the display unit housing DIS. Backlight BLm, main substrate 211 disposed in the radiation direction of the light emitted from backlight BLm (that is, the visual field side), counter substrate 212 disposed to face main substrate 211, and main substrate 211, the liquid crystal encapsulation layer 213 provided between the counter substrate 212 and the counter substrate 212, the driver circuit (driver IC chip) 214 mounted on the main substrate 211, and the flexible printed wiring 215 connected to the driver circuit 214. And a configuration provided with.

  Further, as shown in FIG. 9, the sub-display 220 includes a backlight BLs including a light guide plate 226 and a light source 227 so that a field of view is set on the back side (lower side of the drawing) of the display unit housing DIS, and the backlight Provided between the main substrate 221 disposed in the radiation direction of the irradiation light by the light BLs (the visual field side), the counter substrate 222 disposed so as to face the main substrate 221, and the main substrate 221 and the counter substrate 222. A liquid crystal encapsulation layer 223, a driver circuit (driver IC chip) 224 mounted on the main substrate 221, and an image display unit DSs including a flexible printed wiring 225 connected to the driver circuit 224. ing.

  As described above, the display having such a configuration has a configuration in which the back sides of the individual liquid crystal display devices are stacked so as to face each other. There was a problem that the thickness of the housing was increased. In addition, since each liquid crystal display device has a configuration including a plurality of (two) individual liquid crystal display devices, each liquid crystal display device requires peripheral circuits such as a driver circuit and a backlight. , Had the problem of increased power consumption.

  As a technology for solving such problems of the display device scale and power consumption, an organic electroluminescent element (hereinafter referred to as “organic EL element”) that has been attracting attention as a next-generation display device following a liquid crystal display device in recent years. And a light emitting element type display including a display panel in which self-luminous light emitting elements (optical elements) such as inorganic electroluminescent elements and light emitting diodes are two-dimensionally arranged are being studied. .

Here, an organic EL element which has been actively researched and developed in recent years as a self-luminous light emitting element will be briefly described.
FIG. 10 is a schematic configuration diagram showing a basic configuration of an organic EL element in the prior art.
As schematically shown in FIG. 10, the organic EL element has an anode electrode 312 made of a transparent electrode material such as ITO (Indium Thin Oxide) on one surface side (lower side of the drawing) of a transparent insulating substrate 311 such as a glass substrate. An organic layer composed of a hole transport layer (hole injection layer) 313a made of a polymer hole transport material and an electron transport light emitting layer (light emitting layer) 313b made of a polymer electron transport light emitting material. It has a cross-sectional structure in which an EL layer 313 and a cathode electrode 314 having a reflection characteristic made of a metal material are sequentially stacked. In the figure, reference numeral 315 denotes a sealing substrate for sealing the organic EL element with the insulating substrate 311.

  In the organic EL element having such a configuration, as shown in FIG. 10, a positive voltage is applied from the DC voltage source BAT to the anode electrode 312 and a negative voltage is applied to the cathode electrode 314, thereby being injected into the hole transport layer 313a. The light hν is emitted based on the energy when the holes and the electrons injected into the electron-transporting light-emitting layer 313b recombine in the organic EL layer 313. This light hv is reflected directly or by the cathode electrode 314, passes through the transparent anode electrode 312 and is emitted to the other surface side (viewing side; upper side of the drawing) of the insulating substrate 311. At this time, the emission intensity of the light hν is controlled according to the amount of current flowing between the anode electrode 312 and the cathode electrode 314.

  When an organic EL panel in which such organic EL elements are two-dimensionally arranged is applied to form a display having a field of view set on both the front side and the back side as described above, for example, the liquid crystal shown in FIG. Similar to the configuration in which the display devices are stacked and arranged, a structure in which the back side of the organic EL panel (the sealing substrate 315 shown in FIG. 10) is opposed to each other can be considered. In this case, although the thickness of the display can be reduced to some extent, a peripheral circuit (such as a driver circuit excluding the backlight) is required for each organic EL panel. There was a problem that there was a limit in reducing power consumption.

  Therefore, for example, as described in Patent Document 1 and the like, the cathode electrode 314 of the organic EL element shown in FIG. 10 is configured by a laminated structure including a transparent or translucent metal ultrathin film and a transparent electrode, It is known that radiation light is extracted not only on the anode electrode 311 side which has been conventionally regarded as the visual field side but also on the cathode electrode 314 side (sealing substrate 315 side).

JP 2002-252089 A (Fig. 2, pages 2 to 3)

  When the organic EL panel composed of the organic EL elements described in Patent Document 1 as described above is applied, the single organic EL panel displays the image information by taking out the emitted light on both the front side and the back side. Therefore, the thickness of the display can be greatly reduced, the peripheral circuit can be halved to reduce the scale of the display device, and the power consumption can be reduced.

  However, in the organic EL element described in Patent Document 1 or the like, since the laminated structure is composed of a transparent or translucent thin film material, for example, projection (radiation) is performed on the main display side (one surface side). When viewing the displayed image information, there is a problem that the scenery and things on the back side are perceived (transparent) through the display, making it difficult to see the original display image.

  In addition, since the light emitted from the organic EL element is completely diffused light centering on the organic EL layer, light that has been emitted only to the anode electrode side (one surface side of the display) by the cathode electrode having the conventional reflection characteristics. However, since it is also taken out to the cathode electrode side (the other side of the display), the amount of light emitted as image information to one of the visual field sides is reduced (for example, halved), and the image display is reduced. There was a problem that display quality deteriorated due to darkening.

  Therefore, in the present invention, in view of the above-described problems, the background is not seen through from the view side even when the desired image information is displayed using the front side and the back side of a single organic EL panel ( Another object of the present invention is to provide a light emitting element and an image display device capable of maintaining good display quality by suppressing a decrease in the amount of light emitted as image information.

  The invention described in claim 1 has an element structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side of a transparent insulating substrate. In the light emitting device having a perfect diffusion type radiation characteristic, a light transmission part that transmits a part of the light emitted from the light emitting layer is provided in a specific region of the second electrode layer, and the light emitting layer The light emitted from the insulating substrate is simultaneously emitted to one side and the other side of the insulating substrate.

According to a second aspect of the present invention, in the light emitting device according to the first aspect, the light transmission portion is defined by the first electrode layer, the light emitting layer, and the second electrode layer. It is characterized in that it is set to have a smaller area than the light emitting region in one surface direction.
According to a third aspect of the present invention, in the light emitting device according to the first or second aspect, the light transmitting portion is an opening formed in the second electrode layer so that the light emitting layer is exposed. And

According to a fourth aspect of the present invention, in the light emitting device according to the first or second aspect, the light transmitting portion is made of a transparent conductive material.
According to a fifth aspect of the present invention, in the light emitting device according to the fourth aspect, the first electrode layer is provided with a light blocking portion made of an opaque conductive material in a region corresponding to the light transmitting portion. It is characterized by that.

  The invention described in claim 6 has an element structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side of the transparent insulating substrate. In the light-emitting element having a perfect diffusion type emission characteristic, a light transmission part that transmits part of the light emitted from the light-emitting layer is provided in a region outside the element formation region of the light-emitting element, and the light-emitting layer The light emitted from the insulating substrate is simultaneously emitted to one side and the other side of the insulating substrate.

According to a seventh aspect of the present invention, in the light emitting device according to the sixth aspect, the light transmission portion is formed in a partition wall provided outside the element formation region so that at least an end portion of the light emitting layer is exposed. It is an opening.
The invention according to claim 8 is the light emitting element according to any one of claims 1 to 7, wherein the light emitting element is an organic electroluminescent element.

  The invention according to claim 9 is provided with a display panel in which a plurality of display pixels are two-dimensionally arranged on a transparent insulating substrate, and the display pixels for each row of the display panel are selected and a floor corresponding to display data is selected. In the image display device that causes the display pixels to emit light at a predetermined luminance gradation by applying a tone signal, and displays desired image information on the display panel, each of the display pixels includes the insulating substrate. A light-emitting element having an element structure in which at least a transparent first electrode layer, a light-emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side, and having a perfect diffusion type radiation characteristic And a light transmission part that transmits a part of the light emitted from the light emitting layer is provided in a specific region of the second electrode layer, and the light emitted from the light emitting layer in each display pixel is provided. One side and other side of the insulating substrate By emitted, and displaying simultaneously the image information on the front side and rear side of the display panel.

  According to a tenth aspect of the present invention, in the image display device according to the ninth aspect, the light is emitted from the light emitting layer of the light emitting element in each display pixel, and is provided on the other surface side of the insulating substrate via the light transmitting portion. The first light emitting region defined by the emitted light is defined by the light emitted from the light emitting layer of the light emitting element and emitted to one surface side of the insulating substrate through the first electrode layer. Compared to the second light emitting region, the area is set smaller.

According to an eleventh aspect of the present invention, in the image display device according to the ninth or tenth aspect, the light transmission portion is an opening formed in the second electrode layer so that the light emitting layer is exposed. Features.
According to a twelfth aspect of the present invention, in the image display device according to the ninth or tenth aspect, the light transmitting portion is made of a transparent conductive material, and the first electrode layer corresponds to the light transmitting portion. A light blocking portion made of an opaque conductive material is provided in the region.

  A thirteenth aspect of the invention includes a display panel in which a plurality of display pixels are two-dimensionally arranged on a transparent insulating substrate, and the display pixels for each row of the display panel are selected, and a floor corresponding to display data is selected. In the image display device that causes the display pixels to emit light at a predetermined luminance gradation by applying a tone signal, and displays desired image information on the display panel, each of the display pixels includes the insulating substrate. A light-emitting element having an element structure in which at least a transparent first electrode layer, a light-emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side, and having a perfect diffusion type radiation characteristic And a light transmission part that transmits a part of the light emitted from the light emitting layer is provided in a boundary region between the display pixels, and the light emitted from the light emitting layer in each display pixel is provided with the insulating property. One side and other side of the board By emitted, and displaying simultaneously the image information on the front side and rear side of the display panel.

According to a fourteenth aspect of the present invention, in the image display device according to the thirteenth aspect, each display pixel radiates from the light emitting layer of the light emitting element and passes through the light transmission portion to the other surface side of the insulating substrate. The first light emitting region defined by the emitted light is defined by the light emitted from the light emitting layer of the light emitting element and emitted to one surface side of the insulating substrate through the first electrode layer. The second light emitting region is set so as not to overlap in a plane.
According to a fifteenth aspect of the present invention, in the image display device according to the thirteenth or fourteenth aspect, the light transmission portion is formed in a partition wall provided in the boundary region so that at least an end portion of the light emitting layer is exposed. It is characterized by being an opening.

  A light-emitting element and an image display device according to a first aspect of the present invention include an image display including a display panel in which a plurality of display pixels including a light-emitting element having a perfect diffusion type radiation characteristic, such as an organic EL element, are arranged two-dimensionally In the apparatus, a transparent first electrode layer (anode electrode), a light-emitting layer (organic EL layer), and a non-transparent second electrode layer (cathode electrode) having reflection characteristics, which constitute a light-emitting element of each display pixel. Of these, a specific region (for example, a substantially central portion) of the second electrode layer is provided with a light transmission portion made of an opening or a transparent thin film material (for example, a conductive material), and the light transmission portion is interposed through the light transmission portion. A part of the light emitted from the light emitting layer is emitted to the other surface side of the insulating substrate, and most of the light emitted from the light emitting layer is transmitted to the one surface side of the insulating substrate through the first electrode layer. By emitting light, the front and back sides of the display panel can be It is configured to display the desired image information.

  Here, the first light-emitting area defined by the light emitted to the other surface side of the insulating substrate through the light transmission portion is, for example, image information displayed on the back side of the display panel having moderate brightness. As shown in FIG. 2, the arrangement position, size, shape, etc. of the light transmission part are set, and the second defined by the light emitted to one surface side of the insulating substrate through the first electrode layer. It is set to have a smaller area than the light emitting region.

  According to this, in each display pixel (light emitting element) arranged in a single display panel in which a plurality of display pixels including light emitting elements such as organic EL elements are arranged two-dimensionally on a transparent insulating substrate, Since light emitted from the light emitting layer can be emitted simultaneously with a predetermined amount of light to one side and the other side of the insulating substrate, desired image information can be displayed on both the front side and the back side of the display panel. Can be displayed simultaneously, the image display device can be reduced in size and thickness, and power consumption can be reduced.

  In addition, the light transmission portion (first light emitting region) provided in the second electrode layer constituting the light emitting element of each display pixel is compared with the second light emitting region set on one surface side of the insulating substrate. By being configured to have a small area, light transmission from one surface side of the insulating substrate to the other surface side (or from the other surface side to the one surface side) can be suppressed. When viewing the image information displayed on the side or the back side, the background is not easily seen through the display panel, and the desired image information can be viewed well.

  Further, in the light emitting element and the image display device according to the present invention, a transparent conductive material (electrode material) is applied as the light transmission part, and the reflection characteristic is applied to the region corresponding to the light transmission part of the first electrode layer. You may have the structure which provided the light-shielding part which applied the opaque electroconductive material (electrode material) which has.

  According to this, the light emitted in the light emitting layer between the transparent first electrode layer and the second electrode layer having reflection characteristics is reflected directly or by the second electrode layer, The light is emitted to one surface side of the insulating substrate through the one electrode layer, and light is also emitted in the light emitting layer between the light transmitting portion and the light blocking portion having reflection characteristics. The emitted light is reflected directly or reflected by the light blocking part and emitted to the other side of the insulating substrate through the light transmitting part, so the amount of light emitted to the front side of the display panel is almost attenuated. Therefore, the amount of light emitted to the back side can be increased, and clear and bright display image information can be displayed on both the front side and the back side of the display panel.

  In addition, in order to increase the amount of light emitted to the back side of the display panel, the light transmitting part and the light blocking part are opposed to each other so that they have the same area. Alternatively, when viewing the image information displayed on the back side, the background is not seen through the display panel, and only desired image information can be viewed well.

  Furthermore, the light emitting element and the image display device according to the second invention are formed of an opening or a transparent thin film material in a boundary region between display pixels (more specifically, a region outside the element formation region of the light emitting element). A light transmission part is provided, and a part of the light emitted from the light emitting layer through the light transmission part is emitted to the other surface side of the insulating substrate, and almost all of the light emitted from the light emitting layer is A desired image information is simultaneously displayed on the front side and the back side of the display panel by emitting light to one surface side of the insulating substrate through the first electrode layer.

  According to this, the light radiated from the light emitting layer of each display pixel (light emitting element) arranged in a single display panel is simultaneously emitted to the one surface side and the other surface side of the insulating substrate with a predetermined light amount respectively. Therefore, desired image information can be simultaneously displayed on both the front side and the back side of the display panel, the image display device can be reduced in size and thickness, and power consumption can be reduced. it can.

  In this case, the light transmission part (first light emitting region) that emits light to the other surface side of the insulating substrate does not overlap with the second light emitting region set on the one surface side of the insulating substrate in a planar manner. By being provided in the region (partition wall), the other surface side (or the other surface side from the other surface side) is not seen through from the one surface side of the insulating substrate, and the second light emitting region and the first light emitting region Since a desired amount of light can be emitted to both the one side and the other side using the entire light emitting area, the background is not seen through when viewing image information, and the display panel In both the front side and the back side, only desired image information can be visually recognized with a clear and bright display image quality.

Embodiments of a light emitting element and an image display device according to the present invention will be described in detail below.
First, the overall configuration of the image display apparatus according to the present invention will be briefly described.
FIG. 1 is a schematic block diagram showing an example of the overall configuration of an image display apparatus according to the present invention. Here, in the following description, for each display pixel constituting the display panel, for the sake of convenience, a light emission driving current having a current value corresponding to the display data is based on the gradation signal voltage corresponding to the display data. A case of having a circuit configuration including a voltage designation type light emission driving circuit to be generated and an organic EL element which is a current control type light emitting element that emits light with a predetermined luminance gradation based on the light emission driving current explain.

  As shown in FIG. 1, the display device 100 according to the present embodiment generally includes a plurality of scanning lines SL1, SL2,... (Hereinafter collectively referred to as “scanning lines SL”) arranged so as to be orthogonal to each other. ”) And a plurality of data lines DL1, DL2,... (Hereinafter collectively referred to as“ data lines DL ”), at least near the intersections of the light emission drive circuit DC and the organic EL element (current control type). A display panel 110 in which a plurality of display pixels EM each having an OEL are arranged, and connected to each scanning line SL of the display panel 110, and sequentially selected to each scanning line SL at a predetermined timing (high level). ) Scanning signals Vscan1, Vscan2,... (Hereinafter collectively referred to as “scanning signal Vscan”) are applied to the gate driver for setting (scanning) the display pixels EM for each row to a selected state. Are connected to each data line DL of the display panel 110 and generate gradation signal voltages Vdata1, Vdata2,... (Hereinafter collectively referred to as “gradation signal voltage Vdata”) based on the display data. A system for generating and outputting a data driver (signal driving circuit) 130 to be supplied to each data line DL, and at least a scanning control signal and a data control signal for controlling the operating state of the gate driver 120 and the data driver 130 Based on the controller 140 and a video signal supplied from the outside of the display device 100, display data (display signal) is generated and supplied to the data driver 130, and the display data is displayed on the display panel 110 as an image. Timing signal (system clock, etc.) is extracted or generated and supplied to the system controller 140 Is configured to include a, a display signal generation circuit 150.

  For example, as shown in FIG. 1, each display pixel EM includes an n-channel thin film transistor Tr11 having a gate terminal connected to the scanning line SL, a source terminal and a drain terminal connected to the data line DL and the contact N11, and a gate terminal. Is connected to the contact N11, and a p-channel type thin film transistor Tr12 having a source terminal connected to the power supply line VL, and an anode terminal connected to the drain terminal of the thin film transistor Tr12 of the light emission drive circuit DC. The organic EL element OEL has a cathode terminal connected to the ground potential (Vgnd). In the light emission drive circuit DC shown in FIG. 1, Ca is a parasitic capacitance (retention capacitance) formed between the gate and source of the thin film transistor Tr12, or an auxiliary capacitance (retention capacitance) added between the gate and source. It is.

  In the image display device having such a configuration, the display pixels EM in an arbitrary row of the display panel 110 are set to a selected state based on the scanning signal Vscan applied from the gate driver 120 to the scanning line SL at a predetermined timing. Then, the gradation signal voltage Vdata is applied from the data driver 130 via the data line DL to the display pixel EM set in the selected state, so that it is supplied to the organic EL element OEL in the light emission drive circuit DC. The current value of the light emission drive current is controlled, and the organic EL element OEL emits light with a predetermined luminance gradation corresponding to display data.

  Note that the display pixel applicable to the display device according to the present invention is not limited to the configuration shown in this embodiment, and at least a light emission driving current having a current value corresponding to display data is supplied to the light emitting element. For example, a current designation type light emission drive circuit that generates a light emission drive current based on a grayscale signal current according to display data may be applied. In addition, in a light emitting element applied to a display pixel, any light other than an organic EL element can be used as long as light emitted and radiated based on a current driving current supplied from a light emission driving circuit has a perfect diffusion type radiation characteristic. Other light emitting elements may be applied.

<First Configuration Example of Display Pixel>
Next, the display pixel unit applied to the image display device according to the present embodiment described above will be described in detail with reference to the drawings.
FIG. 2 is a schematic diagram illustrating a first configuration example of an element structure of an organic EL element provided in a display pixel applied to the image display apparatus according to the present embodiment. Here, FIG. 2B is a schematic cross-sectional view showing the element structure of the organic EL element, and FIGS. 2A and 2C are one side of the organic EL element shown in FIG. It is the schematic plan view seen from the side (upper surface side) and the other surface side (lower surface side). In FIGS. 2A and 2C, the distribution of the light emission amount in the light emission region is hatched for convenience.

  An organic EL element (light emitting element) OEL applied to the image display apparatus according to the present embodiment is schematically shown in FIG. 2B, and a transparent insulating substrate 11 and a transparent insulating substrate 11 arranged to face each other. An anode electrode (first electrode layer) 12 made of a transparent electrode material such as ITO, a hole transport layer (hole injection layer) 13a, and an electron transporting light emitting layer (light emitting layer) 13b between the transparent sealing substrates 15 An organic EL layer (light-emitting layer) 13 and a cathode electrode (second electrode layer) 14 made of a metal material having reflection characteristics (opaque), and the cathode electrode 14. An opening (through hole; light transmission portion) HLa having an arbitrary shape is formed at an arbitrary position. Here, in this configuration example, as shown in FIG. 2C, a rectangular opening HLa is formed in a substantially central portion of the cathode electrode 14.

  In the organic EL element OEL according to the present configuration example, as shown in FIG. 2B, most of the light (light Hνx) emitted from the organic EL layer 13 during the light emission operation is directly or reflective. So that the light is emitted to one side (upper side in the drawing) via the transparent anode electrode 12 and the insulating substrate 11, and the organic EL layer 13 is exposed to the cathode electrode 14. By providing the opening HLa, a part of the light (light Hνa) emitted from the organic EL layer 13 in the direction of the cathode electrode 14 passes through the opening HLa and the transparent sealing substrate 15. The light is emitted to the other side (lower side in the drawing).

  As a result, as shown in FIG. 2A, from the front side of the image display device 100 (display panel 110), each layer constituting the organic EL element OEL (the organic EL layer 13, the anode electrode 12, and the cathode electrode 14). The light emitted from the organic EL layer 13 is visually recognized in the substantially entire region of the light emitting region (second light emitting region) ARel defined by the two-dimensional spread. Here, in the area ARhl corresponding to the opening HLa provided in the cathode electrode 14, no light emission operation is performed in the organic EL layer 13, but due to diffusion in the organic EL layer 13 and reflection by the cathode electrode 14, Since the light emitted around the opening HLa is emitted also in the area ARhl, the attenuated light is visually recognized by the amount of light corresponding to the area of the opening HLa.

  On the other hand, as shown in FIG. 2C, from the back side of the image display device 100 (display panel 110), in a region (first light emitting region) ARha corresponding to the opening HLa provided in the cathode electrode 14. Only the light emitted from the organic EL layer 13 is visible. Here, as described above, in the area ARha corresponding to the opening HLa, no light emission operation is performed in the organic EL layer 13, but due to diffusion in the organic EL layer 13 and reflection by the cathode electrode 14, the opening HLa. The amount of light corresponding to the area is visually recognized.

Next, a specific configuration example of a display pixel to which the organic EL element having the above-described element structure is applied will be described in more detail in correspondence with the display pixel EM (light emission drive circuit DC) illustrated in FIG.
FIG. 3 is a configuration diagram showing a specific configuration example (circuit layout and cross-sectional structure) of a display pixel portion to which an organic EL element having an element structure according to this configuration example is applied. Here, FIG. 3A is a plan view of a main part viewed from the other surface side of the organic EL element, and FIG. 3B shows an element structure of the organic EL element shown in FIG. It is a schematic sectional drawing in the AA cross section.

  As shown in FIG. 3A, the display pixel EM having the circuit configuration as shown in FIG. 1 includes, for example, a scanning line SL arranged in the row direction and the scanning line SL. A pixel formation region is defined in a rectangular region surrounded by a data line DL arranged orthogonally in the column direction and a power supply line VL arranged in parallel to the data line DL.

  The light emission drive circuit DC shown in FIG. 1 includes thin film transistors Tr11 and Tr12, a capacitor Ca, and a thin film transistor along substantially the outer edge of the pixel formation region (formation region of the scanning line SL, the data line DL, and the power supply line VL). It is configured by arranging an inter-element wiring portion Lbw for connecting between Tr11 and Tr12. In FIG. 3A, EG1, ES1, and ED1 are a gate electrode, a source electrode, and a drain electrode of the thin film transistor Tr11, respectively, and EG2, ES2, and ED2 are a gate electrode, a source electrode, and a drain electrode of the thin film transistor Tr12, respectively. It is.

  In addition, as shown in FIGS. 3A and 3B, the organic EL element OEL has a region for forming the light emission drive circuit DC (thin film transistors Tr11, Tr12, inter-element wiring portion Lbw, etc.) among the pixel formation regions. A transparent region such as ITO connected to the drain electrode ED2 of the thin film transistor Tr12 is formed on the insulating substrate 111 in a region excluding the light emitting region ARel of the display pixel EM via an insulating film (gate insulating film of the thin film transistor Tr12). The anode electrode 112, the organic EL layer 113 composed of the hole transport layer 113a and the electron transporting light emitting layer 113b, and the cathode electrode 114 composed of a metal material and having reflective properties are sequentially laminated. Here, a rectangular opening HLa is provided at a substantially central portion of the cathode electrode 114.

  Further, in the boundary region between the organic EL element OEL formation regions (that is, the light emitting regions ARel) of the display pixels EM arranged adjacent to each other, for example, an insulating material that isolates the formation regions of both organic EL elements OEL The thin film transistors Tr11 and Tr12, the inter-element wiring portion Lbw, and the like constituting the light emission drive circuit DC are formed on the insulating substrate 111 in the region where the partition wall 116 is formed. Further, the entire region on the insulating substrate 111 where the organic EL element OEL and the partition wall 116 are formed is sealed with a sealing layer 117 and a sealing substrate 115 having transparency.

  3A, in order to simplify the illustration, the scanning line SL, the data line DL, the power supply line VL, the thin film transistors Tr11 and Tr12, the anode electrode 112, and the anode electrode 112 which are laid out on the insulating substrate 111. Only the inter-element wiring portion Lbw is shown, and in FIG. 3B, only the organic EL element OEL, the thin film transistor Tr12, the partition wall 116, the sealing layer 117, and the sealing substrate 115 are shown.

  Further, in this configuration example, the configuration in which the partition 116 made of an insulating material is provided in the boundary region between the display pixels EM (organic EL elements OEL) is shown. However, the configuration in which the display pixels are insulated from each other by such a partition. In addition to this, for example, a configuration in which a space serving as the boundary region is filled with a sealing resin (corresponding to the sealing layer 117 described above) or an inert gas may be applied.

  According to an image display device (display panel) to which a display pixel having such an element structure is applied, a single organic EL element (an insulating substrate 111 and a sealing substrate 115) are respectively disposed between opposing transparent substrates (insulating substrate 111 and sealing substrate 115). A plurality of display pixels each having a complete nucleic acid type emission characteristic) are two-dimensionally arranged, and an organic EL is formed on one side (insulating substrate side) of the laminated structure of the organic EL elements constituting each display pixel. Most of the light emitted from the layer can be emitted, and a part of the light emitted from the organic EL layer can be emitted to the other side (sealing substrate side). And image information can be displayed on both the back side and the back side.

  In this case, unlike the configuration in which the liquid crystal display device shown in the prior art (see FIG. 9) is applied, it is not necessary to provide a backlight, and an image is displayed on both the front side and the back side only with a single display panel. Since information can be displayed, the image display device can be reduced in size and thickness, and power consumption can be reduced.

  In addition, an opening having a smaller area than the light emitting region is provided in the cathode electrode that is provided on the other side of the anode electrode and the cathode electrode constituting the organic EL element of each display pixel and has a reflection characteristic. Therefore, the transmission of light from one surface side to the other surface side (or from the other surface side to the one surface side) can be suppressed, so when viewing the image information displayed on the one surface side and the other surface side, Is difficult to see through, and desired image information can be viewed well.

  Here, in each display pixel (organic EL element), light emitted from the organic EL layer is emitted on substantially one side of the light emitting region, so that image information is displayed with sufficient brightness. On the other side, only light of a light amount corresponding to the size of the opening is emitted, so that it is conceivable that the image information becomes dark. Therefore, the arrangement position, size, shape, and the like of the opening are set so that the image information displayed on the other surface side is visually recognized with appropriate brightness. Accordingly, it is possible to appropriately ensure display image quality on both the front side and the back side of the display panel, and it is possible to suppress a phenomenon in which the background is seen through the display panel as much as possible.

  In this configuration example, a configuration in which an opening is provided in the cathode electrode as a light transmission portion for emitting light emitted from the organic EL layer to the sealing substrate side is shown. For example, the opening may be configured to be filled with a transparent insulating material. In addition, by forming a thin film having reflection characteristics on the anode electrode (organic EL layer side) in the region corresponding to the opening, the amount of light emitted to the sealing substrate side is increased and sealing is performed from the insulating substrate side. It is also possible to block the transmission of light from the stationary substrate side or the side sealing substrate side to the insulating substrate so that it cannot be seen through.

<Second Configuration Example of Display Pixel>
Next, a second configuration example of the display pixel unit applied to the image display apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 4 is a schematic diagram illustrating a second configuration example of the element structure of the organic EL element provided in the display pixel applied to the image display apparatus according to the present embodiment. Here, FIG. 4B is a schematic cross-sectional view showing the element structure of the organic EL element, and FIGS. 4A and 4C are diagrams of one surface of the organic EL element shown in FIG. It is the schematic plan view seen from the side (upper surface side) and the other surface side (lower surface side). 4A and 4C, the light emission amount distribution in the light emitting region is hatched for convenience. In the following description, the same components as those of the display pixel unit shown in the first configuration example described above are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  A second configuration example of the organic EL element OEL applied to the image display apparatus according to the present embodiment is schematically shown in FIG. 4B, and transparent insulating substrates 11 arranged to face each other. The transparent anode electrode 12, the organic EL layer 13 (the hole transport layer 13a and the electron transporting light emitting layer 13b), and the cathode electrode 14 having reflection characteristics (opaque) are sequentially disposed between the sealing substrate 15 and the sealing substrate 15. Arbitrary so that at least the organic EL layer is exposed in a part of the partition wall 16 provided in the boundary region (outside the element formation region) between the organic EL elements OEL of adjacent display pixels. An opening (through hole; light transmitting portion) HLb having the shape of is formed. Here, in this configuration example, as shown in FIG. 4C, the partition wall 16 has a configuration in which an opening HLb having a rectangular planar pattern is formed.

  In the organic EL element OEL according to the present configuration example, as shown in FIG. 4B, most of the light (light Hνx) emitted from the organic EL layer 13 during the light emission operation is directly or reflection characteristics. And is emitted to one surface side (upper side in the drawing) through the transparent anode electrode 12 and the insulating substrate 11, and the organic EL layer 13 is exposed to the partition wall 16. By providing the portion HLb, a part of the light (light Hνb) radiated from the organic EL layer 13 in the direction of the side end face (right direction in the drawing) is converted into the opening HLb and the transparent sealing substrate 15. The light is emitted to the other surface side (the lower side in the drawing) via.

  As a result, as shown in FIG. 4A, from the front side of the image display device 100 (display panel 110), the light is emitted from the organic EL layer 13 in the entire light emitting region (second light emitting region) ARel. Light is visible. Here, as described later, a part of the light emitted from the organic EL layer 13 passes through the opening HLb provided in the region other than the light emitting region ARel (that is, the partition wall 16 in the boundary region). Although the entire area of the light emitting area ARel is visually recognized from the front side, the light emitted from the organic EL layer 13 is visually recognized from the front side with almost no attenuation of the light amount.

  On the other hand, as shown in FIG. 4C, from the back side of the image display device 100 (display panel 110), it is a boundary region between the light emitting regions ARel of the display pixels EM and is provided in the partition wall 16. Of the light emitted from the organic EL layer 13, only the light emitted from the organic EL layer 13 is visually recognized only in the region (first light emitting region) ARhb corresponding to the opening HLb. Here, as described above, in the area ARhb corresponding to the opening HLb, a part of the light emitted from the organic EL layer 13 is emitted to the back side through the opening HLb. The amount of light corresponding to the area (substantially, the area of the organic EL layer 113 exposed in the opening HLb) is visually recognized.

Next, a specific configuration example of a display pixel to which the organic EL element having the above-described element structure is applied will be described in more detail in correspondence with the display pixel EM (light emission drive circuit DC) illustrated in FIG.
FIG. 5 is a configuration diagram showing a specific configuration example (circuit layout and cross-sectional structure) of a display pixel portion to which an organic EL element having an element structure according to this configuration example is applied. Here, FIG. 5A is a plan view of a main part viewed from the other side of the organic EL element, and FIG. 5B shows the element structure of the organic EL element shown in FIG. It is a schematic sectional drawing in a BB cross section. In addition, the same reference numerals are assigned to the same configuration as the specific configuration example of the display pixel unit shown in the first configuration example described above, and the description thereof is simplified or omitted.

  A specific configuration example of a display pixel to which the organic EL element according to the second configuration example is applied is surrounded by a scanning line SL, a data line DL, and a power supply line VL as shown in FIGS. In the pixel formation region, the organic EL element OEL is configured in the light emitting area ARel of each display pixel defined by the partition wall 116, and includes an edge portion (including a side end face) of the organic EL layer 113 of the organic EL element OEL. The cathode electrode 114 and the partition wall 116 are etched away from a partial region of the organic EL layer 113 to a part of the region where the partition wall 116 is formed. In addition, an opening HLb is formed in which the region extending to the thin film transistor Tr12 is exposed.

  According to the image display device (display panel) to which the display pixel having such an element structure is applied, the light emitted from the organic EL layer 113 is emitted from the entire light emitting area ARel on the front side of the display panel 110. Desired image information (for example, a normal rotation image) is displayed and viewed, and on the back side, an opening HLb is provided in a partition wall portion 116 (boundary region) formed between the organic EL elements OEL of each display pixel EM. Since part of the light emitted from the organic EL layer 113 (light emitted in the side surface direction of the organic EL layer 113) is emitted through the opening HLb, the display pixel EM (organic EL element OEL) Light is emitted only in the boundary region between them, and desired image information (for example, a reverse image) is displayed and viewed.

  Therefore, the opening for emitting light to the back side is provided in the boundary region (partition) that does not overlap the light emitting region in a planar manner, so that one side from the other side (or one side from the other side) Side) can be emitted to both the one side and the other side without seeing through, so when viewing the image information, the scenery and things on the back side are visible and visible. Therefore, only desired image information can be satisfactorily visually recognized with a clear and bright display image quality on both the front side and the back side of the display panel.

  In this configuration example, the configuration in which the opening is provided in the partition wall as the light transmitting portion for emitting the light emitted from the organic EL layer to the sealing substrate side is shown. However, the present invention is not limited to this. For example, the opening may have a configuration filled with a transparent insulating material. In addition, the case where the opening is formed so that one side end face of the organic EL layer is exposed, the shape and number of openings are set so that a plurality of side end faces are exposed, The amount of light emitted to the sealing substrate side may be increased.

<Third Configuration Example of Display Pixel>
Next, a third configuration example of the display pixel unit applied to the image display apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 6 is a schematic diagram showing a third configuration example of the element structure of the organic EL element provided in the display pixel applied to the image display apparatus according to the present embodiment. Here, FIG. 6B is a schematic cross-sectional view showing the element structure of the organic EL element, and FIGS. 6A and 6C are diagrams of one surface of the organic EL element shown in FIG. It is the schematic plan view seen from the side (upper surface side) and the other surface side (lower surface side). In FIGS. 6A and 6C, the distribution of the light emission amount in the light emitting region is hatched for convenience. In the following description, the same components as those of the display pixel unit shown in the first configuration example described above are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  As shown in FIG. 6B, a third configuration example of the organic EL element OEL applied to the image display device according to the present embodiment includes a transparent insulating substrate 11 and a transparent substrate that are arranged to face each other. An organic EL element OEL having a configuration similar to that of the above-described first configuration example is formed between the sealing substrates 15, and an opening HLc formed in an arbitrary shape at least at an arbitrary position of the cathode electrode 14. A transparent electrode material (conductive material) is embedded therein, and a part of the cathode electrode (hereinafter referred to as a “transparent cathode electrode portion” for the sake of convenience; a light transmitting portion) 14H is provided. Here, in the present configuration example, as shown in FIG. 6C, a rectangular opening HLc is formed at a substantially central portion of the cathode electrode 14, and a transparent electrode material such as ITO is formed in the opening HLc. The transparent cathode electrode portion 14H is provided by filling and forming.

  Furthermore, as a desirable form, as shown in FIG. 6B, the region facing (or corresponding to) the transparent cathode electrode portion 14H of the anode electrode 12 is formed to be an opaque electrode having reflection characteristics. To do. Specifically, an opening is provided in the anode electrode 12 in a region facing the transparent cathode electrode portion 14H, and an opaque electrode material (conductive material) having a reflection characteristic is embedded in the opening, and a part of the anode electrode ( Hereinafter, for the sake of convenience, it will be referred to as a “reflective anode electrode part”; a light blocking part) 12H, and the reflection characteristic on the surface of the anode electrode 12 (on the organic EL layer 13 side) in the region facing the transparent cathode electrode part 14H. A structure in which a conductive thin film is formed can be favorably applied.

  In the organic EL element OEL according to the present configuration example, as shown in FIG. 6B, most of the light (light Hνx) emitted from the organic EL layer 13 during the light emission operation is directly or reflection characteristics. And is emitted to one surface side (upper side in the drawing) via the transparent anode electrode 12 (excluding the reflective anode electrode portion 12H) and the insulating substrate 11, and to the cathode electrode 14. A transparent cathode electrode portion 14H is provided so that the emitted light from the organic EL layer 13 is transmitted, and the emitted light from the organic EL layer 13 is reflected in a region corresponding to the transparent cathode electrode portion 14H of the anode electrode 12. By providing the reflective anode electrode portion 12H as described above, a part of the light (light Hνc) emitted from the organic EL layer 13 in the direction of the cathode electrode 14 is part of the transparent cathode. The light is emitted to the other surface side (lower side in the drawing) through the cathode electrode portion 14H and the transparent sealing substrate 15.

  As a result, as shown in FIG. 6A, from the front side of the image display device 100 (display panel 110), the light is emitted from the organic EL layer 13 in substantially the entire light emitting region (second light emitting region) ARel. Visible light is visible. Here, in the region corresponding to the reflective anode electrode portion 12H provided on the anode electrode 12 (that is, the region corresponding to the transparent cathode electrode portion 14H provided on the cathode electrode 14) ARhl, the radiation from the organic EL layer 13 is emitted. Since light is not transmitted, the attenuated light is visually recognized by the amount of light corresponding to the area of the reflective anode electrode portion 12H.

  On the other hand, as shown in FIG. 6C, from the back side of the image display device 100 (display panel 110), a region corresponding to the transparent cathode electrode portion 14H provided on the cathode electrode 14 (first light emitting region). Only in ARhc, the light emitted from the organic EL layer 13 is visible. Here, as described above, in the area ARhc corresponding to the transparent cathode electrode portion 14H, the light emitted from the organic EL layer 13 between the reflective anode electrode 12H and the transparent cathode electrode portion 14H is directly or the reflective anode electrode 12H. And is emitted through the transparent cathode electrode portion 14H and the sealing substrate 15, so that a larger amount of light than the organic EL element according to the first configuration example has an area of the transparent cathode electrode portion 14H. Is taken out and visually recognized.

Next, a specific configuration example of a display pixel to which the organic EL element having the above-described element structure is applied will be described in more detail in correspondence with the display pixel EM (light emission drive circuit DC) shown in FIG.
FIG. 7 is a configuration diagram showing a specific configuration example (circuit layout and cross-sectional structure) of the display pixel unit to which the organic EL element having the element structure according to this configuration example is applied. Here, FIG. 7A is a plan view of a main part viewed from the other side of the organic EL element, and FIG. 7B shows the element structure of the organic EL element shown in FIG. It is a schematic sectional drawing in CC cross section. In addition, the same reference numerals are assigned to the same configuration as the specific configuration example of the display pixel unit shown in the first configuration example described above, and the description thereof is simplified or omitted.

  A specific configuration example of a display pixel to which the organic EL element according to the third configuration example is applied is surrounded by a scanning line SL, a data line DL, and a power supply line VL as shown in FIGS. In the pixel formation region, an organic EL element OEL is formed in the light emitting area ARel of each display pixel, and a transparent cathode electrode portion 114H is formed at a substantially central portion of the cathode electrode 114 in each layer constituting the organic EL element OEL. A reflective anode electrode portion 112 </ b> H is provided at a substantially central portion of the anode electrode 112.

  According to the image display device (display panel) to which the display pixel having such an element structure is applied, on the front side of the display panel 110, the light emitted from the organic EL layer 113 is emitted from substantially the entire light emitting area ARel. Thus, desired image information (for example, a normal rotation image) is displayed and visually recognized, and on the back side, the reflective anode electrode portion 112H and the transparent cathode electrode portion 114H are provided to face each other, whereby the organic EL layer 113 between the electrode portions is provided. Is emitted through the opening HLb, and desired image information (for example, a reverse image) is displayed and visually confirmed.

  Accordingly, since light emitted from the organic EL layer between the reflective anode electrode portion and the transparent cathode electrode portion is favorably emitted to the back side, the light is emitted to the front side as compared with the organic EL element according to the first configuration example. The amount of light emitted to the back side can be increased with almost no attenuation of the amount of light emitted, and the image information has clear and bright display image quality on both the front side and the back side of the image display device (display panel). Can be displayed.

  In addition, in order to emit light to the back side of the display panel (in order to increase the amount of light), an opaque reflective anode electrode portion and a transparent cathode electrode portion are opposed to each other so that they have the same area. Therefore, a desired amount of light can be emitted to both the one side and the other side without being seen through from one side to the other side (or from the other side to one side). When viewing the information, the scenery and things on the back side are not seen through, and only desired image information can be seen with good display image quality.

  In this configuration example, a transparent cathode electrode portion is formed on a cathode electrode having reflection characteristics, and a reflection anode electrode portion having reflection characteristics is formed on a transparent anode electrode. For example, only the transparent cathode electrode portion is formed on the cathode electrode, and the anode electrode in the corresponding region is left as it is (no reflective anode electrode portion is formed).

  Further, in the image display device to which the display pixel shown in each configuration example described above is applied, the area of the light emitting region set on the back side is smaller than the light emitting region set on the front side. Although the configuration in which the light transmission part is formed (that is, the configuration in which the light amount extracted on the back side is smaller than the light amount extracted on the front side) has been described, the present invention is not limited to this. In particular, in the second and third configuration examples, for example, the amount of light extracted to the front side and the back side may be configured to be equal to each other.

  Here, in a case where the amount of light extracted to the back side is smaller than the amount of light extracted to the front side, for example, in a recent cellular phone or the like, the sub display is compared with the main display. However, there are many uses for displaying relatively simple text information and images, such as time display and incoming call display, and even if the display image quality (brightness) is low to some extent, there is no problem. It can be favorably applied to existing electronic devices (such as mobile phones). On the other hand, in the case where the amounts of light extracted to the front side and the back side are the same, the main display and the sub display display image information of the same display quality, and the display An electronic device (such as a mobile phone) whose background is not seen through can be realized.

  Furthermore, in the image display device according to the present invention, the image information inverted from each other (that is, the normal image and the reverse image) is displayed on the front side and the back side of the display panel. When the image display device according to the present invention is applied to the mobile phone 200 as shown in FIG. 1, normally, in a state where the image information on the main display 210 is viewed, the image information displayed on the sub display 220 is used (viewing Therefore, even if image information that is inverted between the main display 210 and the sub-display 220 is displayed, there is a possibility that a serious trouble may occur in the use of the electronic device equipped with the image display device. Very low.

  Therefore, in the mobile phone 200 as shown in FIG. 8, for example, in a state where the display unit housing DIS is opened and the main display 210 is viewed, the image information is displayed in a normal rotation state (at this time, the sub display 220 is displayed). In the state where the display unit housing DIS is closed and the sub-display 220 is viewed, the display state of the image information is driven and controlled so that the image information is displayed in an inverted state. Good usability can be secured.

It is a schematic block diagram which shows an example of the whole structure of the image display apparatus which concerns on this invention. It is the schematic which shows the 1st structural example of the element structure of the organic EL element provided in the display pixel applied to the image display apparatus which concerns on this embodiment. It is a block diagram which shows the specific structural example (circuit layout and cross-sectional structure) of the display pixel part to which the organic EL element which has the element structure which concerns on this structural example is applied. It is the schematic which shows the 2nd structural example of the element structure of the organic EL element provided in the display pixel applied to the image display apparatus which concerns on this embodiment. It is a block diagram which shows the specific structural example (circuit layout and cross-sectional structure) of the display pixel part to which the organic EL element which has the element structure which concerns on this structural example is applied. It is the schematic which shows the 3rd structural example of the element structure of the organic EL element provided in the display pixel applied to the image display apparatus which concerns on this embodiment. It is a block diagram which shows the specific structural example (circuit layout and cross-sectional structure) of the display pixel part to which the organic EL element which has the element structure which concerns on this structural example is applied. It is a schematic block diagram which shows an example of the portable electronic device (cellular phone) provided with the some display in a prior art. It is a schematic sectional drawing which shows the structural example of the image display part of the electronic device in a prior art. It is a schematic block diagram which shows the basic composition of the organic EL element in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Insulating board | substrate 15 Sealing board | substrate 12 Anode electrode 12H Reflective anode electrode part 13 Organic EL layer 14 Cathode electrode 14H Transparent cathode electrode part 100 Image display apparatus 110 Display panel HLa, HLb, HLc Opening part DC light emission drive circuit OEL Organic EL element ARel light emitting area

Claims (15)

It has a device structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side of a transparent insulating substrate, and has a completely diffusing radiation characteristic. In a light emitting device having
A light transmitting portion that transmits a part of the light emitted from the light emitting layer is provided in a specific region of the second electrode layer, and the light emitted from the light emitting layer is connected to one surface side of the insulating substrate. A light-emitting element that emits simultaneously to the other surface side. The light transmission portion is set to have a small area as compared to the light emitting region in the one surface direction of the light emitting element, which is defined by the first electrode layer, the light emitting layer, and the second electrode layer. The light-emitting element according to claim 1. The light-emitting element according to claim 1, wherein the light transmission part is an opening formed in the second electrode layer so that the light-emitting layer is exposed. The light-emitting element according to claim 1, wherein the light transmission part is made of a transparent conductive material. The light emitting element according to claim 4, wherein the first electrode layer is provided with a light blocking portion made of an opaque conductive material in a region corresponding to the light transmitting portion. It has a device structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially laminated on the other surface side of a transparent insulating substrate, and has a completely diffusing radiation characteristic. In a light emitting device having
A light transmission part that transmits part of the light emitted from the light emitting layer is provided in a region outside the element formation region of the light emitting element, and the light emitted from the light emitting layer is on one surface side of the insulating substrate. A light-emitting element that emits simultaneously to the other surface side. The light-emitting element according to claim 6, wherein the light transmission part is an opening formed in a partition wall provided outside the element formation region so that at least an end part of the light-emitting layer is exposed. The light emitting device according to claim 1, wherein the light emitting device is an organic electroluminescent device. By providing a display panel in which a plurality of display pixels are two-dimensionally arranged on a transparent insulating substrate, selecting the display pixels for each row of the display panel, and applying a gradation signal according to display data, In the image display device for causing the display pixels to emit light at a predetermined luminance gradation and displaying desired image information on the display panel,
Each of the display pixels has an element structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially stacked on the other surface side of the insulating substrate. A light-transmitting part that includes a light-emitting element having a completely diffusing radiation characteristic, and a light transmission part that transmits part of the light emitted from the light-emitting layer is provided in a specific region of the second electrode layer.
The image information is simultaneously displayed on the front side and the back side of the display panel by emitting light emitted from the light emitting layer in each display pixel to one side and the other side of the insulating substrate. A characteristic image display device. In each display pixel, the first light emitting region defined by the light emitted from the light emitting layer of the light emitting element and emitted to the other surface side of the insulating substrate through the light transmitting portion is the light emitting element. Compared with the second light emitting region defined by the light emitted from the light emitting layer and emitted to the one surface side of the insulating substrate through the first electrode layer, the area is set to be small. The image display device according to claim 9. The image display device according to claim 9, wherein the light transmission part is an opening formed in the second electrode layer so that the light emitting layer is exposed. The light transmission part is made of a transparent conductive material, and the first electrode layer is provided with a light blocking part made of an opaque conductive material in a region corresponding to the light transmission part. The image display device according to claim 9 or 10, characterized in that By providing a display panel in which a plurality of display pixels are two-dimensionally arranged on a transparent insulating substrate, selecting the display pixels for each row of the display panel, and applying a gradation signal according to display data, In the image display device for causing the display pixels to emit light at a predetermined luminance gradation and displaying desired image information on the display panel,
Each of the display pixels has an element structure in which at least a transparent first electrode layer, a light emitting layer, and an opaque second electrode layer are sequentially stacked on the other surface side of the insulating substrate. A light-transmitting part that includes a light-emitting element having a completely diffusive emission characteristic and that transmits a part of light emitted from the light-emitting layer is provided in a boundary region between the display pixels,
The image information is simultaneously displayed on the front side and the back side of the display panel by emitting light emitted from the light emitting layer in each display pixel to one side and the other side of the insulating substrate. A characteristic image display device. The first light emitting region defined by the light emitted from the light emitting layer of the light emitting element in each display pixel and emitted to the other surface side of the insulating substrate through the light transmitting portion is the light emitting element. The second light-emitting region defined by the light emitted from the light-emitting layer and emitted to the one surface side of the insulating substrate through the first electrode layer is set so as not to overlap in plane. The image display device according to claim 13, wherein 15. The image display device according to claim 13, wherein the light transmission part is an opening formed in a partition wall provided in the boundary region so that at least an end part of the light emitting layer is exposed. .

Images