JP2006128241A - Display device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration for displaying not only from an organic EL element but also from the other light sources, and for improving the lifetime characteristics or luminance characteristics of the display. <P>SOLUTION: The display 1 comprises an organic EL display body 100; and an optical modulator 250 arranged at the rear side opposite to the display surface of the organic EL display body 100. The organic EL display body 100 has a plurality of pixel sections 20, including an emission section 21 having the organic EL element 110 and a light transmission section 22 for transmitting light from the rear side, in the plane. The optical modulator 250 comprises a light source 70; and a light modulation section 200 for modulating light from the light source 70 for each plurality of pixel sections 50 for injecting to the side of the organic EL display body 100. The pixel sections 20 of the organic EL display body 100 and a pixel section 50 of the optical modulator 250 are superposed and arranged in a plan view. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device and an electronic apparatus including the display device.

  As a display device using an organic EL element (organic electroluminescence element), a red pixel portion including an organic EL element that emits red light, a green pixel portion including an organic EL element that emits green light, and emitting blue light. There is known a full-color display device in which blue pixel portions each including an organic EL element are arranged in a predetermined pattern. In a full-color display device using such an organic EL element, if the same display is continued for a long time, image sticking due to deterioration of the light emitting element may occur.

Therefore, Patent Document 1 discloses a display device in which a full-color organic EL display body and a full-color liquid crystal display body are stacked.
JP 2003-289006 A

  In the display device disclosed in Patent Document 1, the organic EL element of the organic EL display must be transparent, but the brightness of the transparent type organic EL element is reduced by half. Therefore, red, green, and blue organic EL elements that can ensure higher luminance and reliability are required. However, the organic EL element has a short life and inferior brightness compared to the inorganic LED element.

  This invention is made | formed in view of the said situation, In a display apparatus provided with the organic electroluminescent display using an organic electroluminescent element, not only the display from an organic electroluminescent element but the display from other light sources can also be performed. It is an object of the present invention to provide a structure that can improve the life characteristics or luminance characteristics of the display device. Specifically, it is an object of the present invention to provide a display device that can suitably prevent or suppress the occurrence of defects such as burn-in even when always lit (fixed display). A further object of the present invention is to provide an electronic apparatus equipped with such a display device.

  In order to achieve the above object, a display device of the present invention includes an organic EL display (organic electroluminescence display) and light modulation disposed on the back side opposite to the display surface of the organic EL display. The organic EL display body has a plurality of pixel portions including a light emitting portion having an organic EL element and a light transmitting portion capable of transmitting light from the back side in the plane. The light modulator includes a light source and a light modulator that modulates light from the light source for each of a plurality of pixel units and emits the light to the organic EL display unit side, and the pixel unit of the organic EL display unit includes: The pixel portion of the light modulator is arranged so as to overlap in plan view.

According to such a display device, the display derived from the organic EL element can be realized from the light emitting portion, and the display derived from the light source can be realized from the light transmitting portion. Therefore, if the light source is appropriately selected according to the display environment, it is possible to provide the display device with display characteristics that the organic EL element does not have or display characteristics that are inferior to the organic EL element.
In particular, if a light source having a longer lifetime and / or higher luminance than an organic EL element (for example, an inorganic LED body using an inorganic material) is used, the display from the light emitting unit and the display from the light transmitting unit are appropriately performed. By switching, it is possible to extend the life and / or increase the brightness of the display device. In addition, when performing a fixed display of a still image or the like, a long-life and / or high-intensity inorganic LED body is used as a light source, and a fixed display is performed in the light transmission portion by light from the light source, thereby It is possible to improve life characteristics and / or luminance characteristics.

  In the display device of the present invention, each of the pixel portions of the organic EL display body includes a first sub-pixel portion that emits light corresponding to red and a second sub-light that emits light corresponding to green. A pixel unit; a third sub-pixel unit that emits light corresponding to blue; and a sub-region that configures the light transmission unit. Each of the sub-pixel unit and the sub-region is partitioned into a predetermined pattern by the partition unit. It can be made. If each sub-pixel portion and sub-region are formed in this way and are divided by the partition portion, the sub-pixel portion and sub-region can be easily and reliably formed in the pixel portion. In particular, if the sub-region is configured with the same pattern as each of the full-color sub-pixel portions as described above, display can be reliably performed in the sub-region by the light from the light source.

  On the other hand, the pixel portion of the organic EL display body includes a first sub-pixel portion that emits light corresponding to red, which constitutes the light-emitting portion, a second sub-pixel portion that emits light corresponding to green, and blue A third sub-pixel unit that emits light corresponding to the above-mentioned, wherein each of the sub-pixel units is partitioned by a partition part, and the light transmission part is formed in the partition part. To do. If the sub-region is formed in the partition portion that partitions the sub-pixel portion in this way, it is not necessary to provide a space for configuring the sub-region separately, and the partition portion that does not contribute to display can be effectively used in the organic EL display body. become able to.

  The organic EL display includes a light reflective electrode formed on the substrate and patterned in each sub-pixel portion, an organic EL layer formed on the light reflective electrode, and at least on the organic EL layer The light transmitting electrode is formed, and the substrate is disposed on the light modulator side. Thus, in the case of a configuration in which light from the organic EL layer is emitted from the side opposite to the substrate (top emission), if the substrate is disposed on the light modulator side, in addition to the display from the organic EL display body, light modulation Display from the body can also be realized. In this case, since it is not necessary to perform patterning particularly on the light transmissive electrode, the process can be simplified.

  The organic EL display includes a light transmissive electrode formed on at least the sub pixel portion on the substrate, and an organic EL layer formed on the light transmissive electrode and patterned in the sub pixel portion. And a light reflective electrode formed on the organic EL layer, and the substrate may be disposed on the display surface side. Thus, in the case of a configuration in which light from the organic EL layer is emitted from the substrate side (top emission), if the substrate is disposed on the side opposite to the light modulator (display surface side), the organic EL display body emits light. In addition to display, display from the light modulator can also be realized.

  The light modulator can be constituted by a liquid crystal device, and the liquid crystal device can suitably modulate the light source light. The light source may be composed of an inorganic LED body made of an inorganic material. According to the inorganic LED body, it is possible to realize a display having a longer life and higher luminance than an organic EL element. . Further, the light source includes a first light emitting unit that emits light corresponding to red, a second light emitting unit that emits light corresponding to green, and a third light emitting unit that emits light corresponding to blue. In this case, full color display can be realized from the light modulator.

  According to another aspect of the present invention, there is provided an electronic apparatus including the above-described display device. As a result, an electronic device that has a long life and can display brightly can be provided.

Hereinafter, an embodiment of a display device of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a cross-sectional configuration of one pixel in the display device of this embodiment, and FIG. 7 is a conceptual diagram showing a planar configuration of the one pixel. Note that the display device in this embodiment includes a plurality of pixels having the structure illustrated in each drawing in a stripe shape or the like in a plane to form a display region.

  As shown in FIG. 1, the display device 1 of the present embodiment has a configuration in which an organic EL display body 100 and a liquid crystal display body (light modulator) 250 are superposed, and the liquid crystal display body 250 is organic. The EL display body 100 is disposed on the back side opposite to the display surface (surface from which light is emitted). At the time of display, display based on the organic EL display body 100 and display based on the liquid crystal display body (liquid crystal device) 250 are appropriately selected, and one or both displays are possible.

  The organic EL display body 100 includes a bank (partition section) 112 that partitions a predetermined area on a base material (substrate) 4, and as shown in FIG. 7, in the plane of the pixel (pixel section) 20. A light emitting unit 21 and a light transmitting unit 22 are provided. In the light emitting unit 21, an organic EL element 110 including an organic EL layer 110R (110G, 110B) is formed between the anode 11R (11G, 11B) and the cathode 12. The light emitting unit 21 includes a red sub-pixel unit R, a green sub-pixel unit G, and a blue sub-pixel unit B according to the light emission color of the organic EL layer 110R (110G, 110B).

  In addition, the organic EL element 110 is not formed in the light transmitting portion 22 of the organic EL display body 100, and only the colorless light transmitting cathode 12 is formed in the present embodiment. A sub-region N is configured in 22. In the present embodiment, the cathode 12 is formed in the light transmitting portion 22, but nothing is formed in the light transmitting portion 22, or other colorless light transmitting member is formed. Also good.

  Each of the sub-pixel portions R, G, B and sub-region N configured in the pixel 20 as described above is surrounded and partitioned by the above-described bank 112, and each has the same pattern.

  On the other hand, the liquid crystal display 250 includes a light source 70, a light guide plate 300 that guides light from the light source 70, and a liquid crystal panel (light modulation unit) 200. The light source 70 is made of an inorganic EL light-emitting body, and is configured to have a red light emitting portion 70R, a green light emitting portion 70G, and a blue light emitting portion 70B so as to emit full color light. The liquid crystal panel 200 modulates the light derived from the light source 70 and emits the light toward the organic EL display body 100 side. The liquid crystal panel 200 employs an active matrix type transmissive liquid crystal device, and no color filter is formed. .

  As shown in FIG. 1, the display device 1 emits red (R) light from the red sub-pixel portion R based on the organic EL display body 100 and the organic EL from the green sub-pixel portion G. Green (G) light based on the display body 100, blue (B) light based on the organic EL display body 100 from the blue sub-pixel unit B, and red color based on the liquid crystal display body 250 from the sub-region N. (R), green (G), and blue (B) colors or mixed colors are emitted. Based on each color light, pixel display by a single color or mixed color is possible.

Next, detailed configurations of the organic EL display body 100 and the liquid crystal display body 250 will be described with reference to FIG.
The organic EL display body 100 mainly includes a translucent substrate 4 and a large number of organic EL elements 110 formed and arranged in a matrix on the substrate 4. The organic EL element 110 includes light-reflective anodes (pixel electrodes) 11R, 11G, and 11B made of aluminum or the like, organic EL layers (light emitting layers) 110R, 110G, and 110B, ITO (indium tin oxide), and the like. And a light-transmitting cathode 12. Such an organic EL display body 100 is a so-called top emission type display body in which light emitted from the organic EL layers 110R, 110G, and 110B is emitted from the cathode 12 side.

  The base material 4 includes a circuit element portion 14 in which a circuit such as a TFT is formed on a substrate 2 made of a translucent glass substrate or the like. In the circuit element portion 14, a base protective film 2c made of a silicon oxide film is formed on the substrate 2, and an island-shaped semiconductor film 141 made of polycrystalline silicon is formed on the base protective film 2c. Note that a source region and a drain region are formed in the semiconductor film 141 by high-concentration P ion implantation, and a portion where P is not introduced is a channel region. Further, a transparent gate insulating film 142 that covers the base protective film 2c and the semiconductor film 141 is formed in the circuit element portion 14, and a gate electrode made of Al, Mo, Ta, Ti, W, or the like is formed on the gate insulating film 142. 143, and a transparent first interlayer insulating film 144a and a second interlayer insulating film 144b are formed on the gate electrode 143 and the gate insulating film 142. The gate electrode 143 is provided at a position corresponding to the channel region of the semiconductor film 141.

  Further, contact holes 145 and 146 connected to the source / drain regions of the semiconductor film 141 are formed in the first and second interlayer insulating films 144a and 144b, and the contact holes 145 and 146 are respectively formed in the contact holes 145 and 146. Conductive material is embedded. On the second interlayer insulating film 144b, light-reflective anodes 11R, 11G, and 11B (hereinafter also referred to as pixel electrodes 11) are formed by patterning in a predetermined shape, and one contact hole 145 is formed. It is connected to the pixel electrode 11. On the other hand, the other contact hole 146 is connected to a power supply line (not shown). In this way, the second thin film transistor 123 connected to each pixel electrode 11 is formed in the circuit element portion 14 for each of the sub-pixel portions R, G, and B.

On the substrate 4, a bank 112 and an organic EL element 110 partitioned by the bank 112 are formed.
The bank part 112 is composed of an inorganic bank layer 112a made of SiO ₂ or the like on the base 4 side, and an organic bank layer 112b formed on the inorganic bank layer 112a. The inorganic bank layer 112a is formed so as to ride on the peripheral edge of the pixel electrode 11, and is arranged so that the periphery of the pixel electrode 11 and the inorganic bank layer 112a overlap in a plan view. It has a structure. The organic bank layer 112b is also disposed so as to overlap with a part of the pixel electrode 11 in a plan view. The organic bank layer 112b is formed of a material having heat resistance such as acrylic resin and polyimide resin and durability (insoluble or hardly soluble) with respect to a solvent.

  On the other hand, the organic EL element 110 includes a plurality of pixel electrodes 11, organic EL layers 110 </ b> R, 110 </ b> G, and 110 </ b> B stacked on the pixel electrodes 11, and a cathode (hereinafter also referred to as a counter electrode) 12. Configured. Here, the pixel electrode 11 is formed of a light-reflective conductive material (for example, aluminum), and is patterned into a substantially rectangular shape in plan view. The cathode 12 is formed of a light-transmitting conductive material (for example, indium tin oxide), and is formed in a solid shape on the entire display area.

  The organic EL layers 110R, 110G, and 110B include a light emitting layer 150 (150R, 150G, and 150B) made of an organic EL material and a hole injection / transport layer 151 (151R, 151G, and 151B) from the substrate 4 side. ing. Note that the hole injection / transport layer 151 has a function of injecting holes of the pixel electrode 11 into the light emitting layer 150, or a function of transporting holes therein. By providing such a hole injecting / transporting layer between the pixel electrode 11 and the light emitting layer 150, characteristics such as light emission efficiency and lifetime of the light emitting layer 150 can be improved. In the light emitting layer 150, holes injected from the hole injection / transport layer 151 and electrons injected from the counter electrode (cathode) 12 are recombined to emit light.

  In this example, the hole injection / transport layer 151 is formed of, for example, a mixture of 3,4-polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS).

  The light emitting layer 150R in the red sub-pixel portion R uses CN-PPV shown as the following compound 1 as a forming material.

  For the light emitting layer 150G in the green sub-pixel portion G, a material in which F8BT shown as the following compound 2 and TFB shown as the compound 3 are mixed in a 1: 1 ratio is used.

  The light emitting layer 150B in the blue sub-pixel portion B uses F8 (polydioctylfluorene) shown as the following compound 4 as a forming material.

  A counter electrode (cathode) 12 is formed on the entire surface of the pixel 20 on the organic EL layers 110R, 110G, and 110B having such a configuration. The counter electrode (cathode) 12 functions as a pair with the pixel electrode 11 so that a current flows through the organic EL layers 110R, 110G, and 110B, and is made of ITO.

  On the other hand, the liquid crystal display body 250 is mainly composed of the light source 70 shown in FIG. 1 and the liquid crystal panel 200 that modulates light from the light source 70. In the liquid crystal panel 200, a liquid crystal layer 40 is sandwiched between a pair of substrates 20 and 30, a pixel electrode 31 is formed on the substrate 30 side on the light source side, and a counter electrode 21 is formed on the opposite substrate 20 side. Yes.

  The substrate 30 on the light source side is made of a light-transmitting glass substrate and has a thin film transistor (TFT, not shown) for driving pixels. The TFT formed for each pixel unit 50 is electrically connected to the pixel electrode 31 similarly formed in a matrix for each pixel, and pixel display is possible based on energization control for the pixel electrode 31. Yes. Here, the pixel unit 50 of the liquid crystal display unit 250 and the pixel unit 20 of the organic EL display unit 100 are arranged so as to overlap in plan view, and at least the light transmission unit 22 can transmit light from the liquid crystal display unit 250. Yes. The pixel electrode 31 is made of a light-transmitting conductive film such as ITO, and an alignment film for liquid crystal alignment (not shown) is formed on the pixel electrode 31 on the liquid crystal layer 40 side.

  The substrate 20 on the organic EL display side is also formed of a light-transmitting glass substrate, and a counter electrode 21 arranged in a solid form on the entire surface of the substrate 20 is formed on the liquid crystal layer side of the substrate 20. The counter electrode 21 is made of a light-transmitting conductive film such as ITO, and an alignment film for liquid crystal alignment (not shown) is formed on the liquid crystal layer 40 side of the counter electrode 21. Further, a polarizing plate (not shown) is disposed on the side of each substrate 20, 30 different from the liquid crystal layer 40, that is, on the organic EL display body 100 and the light guide plate 300 (see FIG. 1) side.

  In the liquid crystal display body 250 having such a configuration, gradation display is possible for each pixel unit 50, and the display is provided for display through the sub-region N of the organic EL display body 100. That is, in the display device 1 of the present embodiment, display can be performed based on one or both of the organic EL display body 100 and the liquid crystal display body 250, and the display derived from the organic EL element 110 can be realized from the light emitting unit 21. From the light transmission part 22, the display originating in the light source 70 is realizable. Therefore, if the light source 70 is appropriately selected according to the display environment, display characteristics that are not found in the organic EL element, or display characteristics that are inferior in the organic EL body can be exhibited. In particular, in this embodiment, since the light source 70 made of an inorganic LED is used, the display device 1 has a long life and / or high luminance. For example, the light from the light source 70 can be used for fixed display. By doing so, it is possible to improve the life characteristics and / or luminance characteristics of the display device 1.

Next, a modification of the display device will be described with reference to FIGS.
In addition, about the following each display apparatus, about the same structural member and component as the display apparatus 1 shown in FIG.1 and FIG.2, the same code | symbol as FIG.1 and FIG.2 is attached | subjected in each figure, and description is abbreviate | omitted. There is also a case.

  Unlike the display device 1, the display device 1 a illustrated in FIG. 3 includes a bottom emission type organic EL display body 100 a. That is, the organic EL display 100a has a configuration in which light is emitted from the base 4 side. Specifically, the translucent base 4 and the translucency formed on the base 4 are provided. Anodes (pixel electrodes) 11R, 11G, and 11B (hereinafter, also referred to as pixel electrodes 11), organic EL layers 110R, 110G, and 110B, and a light-reflective cathode 12 that is selectively formed on the light emitting portion 21. Have.

  Note that neither the electrode nor the organic EL layer is formed on the base material 4 in the light transmission portion 22. Even in such a bottom emission type organic EL display body 100a, the cathode 12 needs to be patterned as compared with the top emission type organic EL display body 100, but the effects of the present invention are sufficiently exhibited. Is possible.

  4 has the top emission type organic EL display body 100b as in the display device 1, the light transmission portion 22 is provided in the bank 112 formation region. Is a feature. That is, in the light-reflective pixel electrodes 11R, 11G, and 11B, the opening 11a is formed at a position overlapping with the bank 112 in plan view, and the light from the liquid crystal display 200 is transmitted through the opening 11a to display this. It is the composition to be used for.

  In this case, as shown in FIG. 8, it is not necessary to separately provide a sub-region N for configuring the light transmission part 22 as compared with the configuration of the display device 1 of FIG. The area of the pixel portions R, G, and B can be increased. In addition, the display device 1c shown in FIG. 5 is also configured to have the light transmission portion 22 in the formation region of the bank 112 and to have the bottom emission type organic EL display body 100c, similarly to the display device 1b. . In this case, each of the cathodes 12R, 12G, and 12B is patterned to have an opening 12a in each bank 112 formation region, and light is transmitted through the opening 12a.

  The display devices 1a, 1b, and 1c as described above can perform display based on the organic EL display bodies 100a, 100b, and 100c from the light emitting section 21, and display based on the liquid crystal display body 250 from the light transmitting section 22. . Then, by appropriately switching the display from each display body, for example, if a fixed display is performed from the light transmitting portion 22, it is possible to suitably prevent or suppress the occurrence of defects such as image sticking in the organic EL display bodies 100a, 100b, and 100c. This can improve the life of the display body.

Next, a specific example of an electronic device including the display devices 1 and 1a to 1c having the above-described configuration will be described.
FIG. 6 is a perspective view showing an example of a mobile phone. In FIG. 6, reference numeral 600 denotes a mobile phone body, and reference numeral 601 denotes a display unit using any one of the display devices 1, 1a to 1c. In this electronic apparatus, since the display devices 1 and 1a to 1c in which the display characteristics are improved are provided as a display unit, the display characteristics of the display unit are sufficiently good. In addition, the display device of the present invention can be suitably used as a display unit in various electronic devices such as portable information processing devices such as word processors and personal computers, and wristwatch type electronic devices.

FIG. 6 is a diagram showing a cross-sectional configuration of a pixel portion of a display device according to an embodiment of the present invention. The figure which shows the cross-sectional structure of a display apparatus in detail similarly. The figure which shows typically the cross-sectional structure of a pixel part about one modification of a display apparatus. The figure which shows typically the cross-sectional structure of a pixel part about the other modification of a display apparatus. The figure which shows typically the cross-sectional structure of a pixel part about the other modification of a display apparatus. FIG. 14 is a perspective view illustrating an example of an electronic device of the invention. The figure which shows typically the planar structure of a pixel part about the display apparatus of FIG. FIG. 5 is a diagram schematically illustrating a planar configuration of a pixel portion in the display device of FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 20 ... Pixel part (organic EL display body side pixel part), 21 ... Light emission part, 22 ... Light transmission part, 50 ... Pixel part (light modulation body side pixel part), 70 ... Light source, 100 ... Organic EL display 110, organic EL element, 200, light modulator (liquid crystal panel), 250, light modulator (liquid crystal display)

Claims (10)

An organic EL display, and a light modulator disposed on the back side opposite to the display surface of the organic EL display,
The organic EL display body has a plurality of pixel portions including a light emitting portion having an organic EL element and a light transmitting portion capable of transmitting light from the back side in the plane,
The light modulator includes a light source, and a light modulator that modulates light from the light source for each of a plurality of pixel units and emits the light to the organic EL display body side,
A display device, wherein a pixel portion of the organic EL display body and a pixel portion of the light modulator are arranged so as to overlap in plan view. The pixel portion of the organic EL display body corresponds to the first sub-pixel portion that emits light corresponding to red, the second sub-pixel portion that emits light corresponding to green, and the blue color that constitute the light-emitting portion, respectively. A third sub-pixel unit that emits light to be emitted, and a sub-region that constitutes the light transmission unit,
The display device according to claim 1, wherein each of the sub-pixel units and the sub-region is partitioned by a partition unit.   The display device according to claim 2, wherein each of the sub-pixel units and the sub-region is formed in the same pattern. The pixel portion of the organic EL display body corresponds to the first sub-pixel portion that emits light corresponding to red, the second sub-pixel portion that emits light corresponding to green, and the blue color that constitute the light-emitting portion, respectively. A third sub-pixel unit that emits light to be emitted,
4. The method according to claim 1, wherein each of the sub-pixel portions is partitioned by a partition portion, and the partition portion is formed with a sub-region that constitutes the light transmission portion. 5. The display device described.   The organic EL display includes a light reflective electrode formed on the substrate and patterned in each sub-pixel portion, an organic EL layer formed on the light reflective electrode, and at least on the organic EL layer 5. The display device according to claim 2, further comprising: a light-transmitting electrode formed, and the substrate being disposed on the light modulator side. 6.   The organic EL display includes a light transmissive electrode formed on at least the sub pixel portion on the substrate, and an organic EL layer formed on the light transmissive electrode and patterned in the sub pixel portion. And a light-reflecting electrode formed on the organic EL layer, and the substrate is disposed on the display surface side. The display device described in 1.   The display device according to claim 1, wherein the light modulator is constituted by a liquid crystal device.   The display device according to claim 1, wherein the light source includes an inorganic LED made of an inorganic material.   The light source includes a first light emitting unit that emits light corresponding to red, a second light emitting unit that emits light corresponding to green, and a third light emitting unit that emits light corresponding to blue. The display device according to any one of claims 1 to 8.   An electronic apparatus comprising the display device according to claim 1.

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