JP2008107726A - Organic el display device and electronic instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology advantageous to obtain electronic instrument attaining a long-time operation, and also, where images can be easily viewed even outdoors. <P>SOLUTION: The electronic instrument of the present invention includes: a plurality of pixels DP, each including an organic EL element; a visible light transmissive solar battery SB positioned on an observer's side related to the plurality of pixels DP; a circular polarizing plate CP interposed between the plurality of pixels DP and the solar battery SB; and accumulating members EA1 and EA2 for accumulating the power generated by the solar battery SB. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent (EL) display device and an electronic device on which the organic electroluminescent (EL) display device is mounted.

  Many electronic devices are equipped with a display device such as an organic EL display device. Such electronic devices, particularly portable devices, are required to be able to operate for a long time and to be easy to see images even outdoors.

Patent Document 1 describes a light-emitting device used for signs and decoration. The light emitter device includes a light emitting unit and a solar cell. The solar cell faces the light emitting unit and transmits light generated in the light emitting unit.
JP 2006-49085 A

  An object of the present invention is to provide a technique advantageous for realizing an electronic apparatus that can operate for a long time and can easily view an image even outdoors.

  According to the first aspect of the present invention, a plurality of pixels each including an organic EL element, a solar cell located on the viewer side with respect to the plurality of pixels and having visible light transparency, An organic EL display device comprising a circularly polarizing plate interposed between a plurality of pixels and the solar cell is provided.

  According to a second aspect of the present invention, there is provided an electronic apparatus comprising the organic EL display device according to the first aspect and a power storage member that accumulates the electric power generated by the solar cell.

  ADVANTAGE OF THE INVENTION According to this invention, the technique advantageous for realization of the electronic device which can operate | move for a long time and is easy to see an image even outdoors is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same referential mark is attached | subjected to the component which exhibits the same or similar function, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a perspective view schematically showing a part of an electronic apparatus in which an organic EL display device according to one embodiment of the present invention is mounted. FIG. 2 is a cross-sectional view schematically showing an example of a structure that can be employed in the organic EL display device shown in FIG. FIG. 3 is a cross-sectional view schematically showing an example of a structure that can be employed in the display panel of the organic EL display device shown in FIG. FIG. 4 is a plan view schematically showing an example of a structure that can be employed in the display panel of the organic EL display device shown in FIG. FIG. 5 is a cross-sectional view schematically showing an example of a structure that can be employed in the solar cell of the organic EL display device shown in FIG.

  The electronic device in FIG. 1 is, for example, a portable device such as a mobile phone, a portable recording / reproducing device, a portable computer, and a wristwatch. This electronic device includes a display panel DP, a video signal line driver XDR, a scanning signal line driver YDR, a solar battery SB, a circularly polarizing plate CP, a controller CNT, a flexible printed circuit board FPC, and a power storage member EA1. And power storage member EA2. The organic EL display device can be configured by, for example, a display panel DP, a video signal line driver XDR, a scanning signal line driver YDR, a solar cell SB, and a circularly polarizing plate CP.

  The display panel DP is a top emission organic EL display panel that employs an active matrix driving method. As shown in FIGS. 2 to 4, the display panel DP includes an array substrate AS and a sealing substrate CS. The array substrate AS and the sealing substrate CS face each other and form a hollow body. Specifically, the central portion of the sealing substrate CS is separated from the array substrate AS. The peripheral edge of the sealing substrate CS is attached to one main surface of the array substrate AS via a frame-shaped seal layer SS shown in FIG.

  The array substrate AS includes the insulating substrate SUB1 shown in FIGS. The insulating substrate SUB1 is a glass substrate, for example.

  An undercoat layer UC shown in FIG. 3 is formed on the substrate SUB1. The undercoat layer UC is formed, for example, by laminating a silicon nitride layer and a silicon oxide layer in this order on the substrate SUB1.

  On the undercoat layer UC, a semiconductor pattern made of, for example, polysilicon containing impurities is formed. A part of this semiconductor pattern is used as the semiconductor layer SC of FIG. Impurity diffusion regions used as a source and a drain are formed in the semiconductor layer SC. Further, another part of the semiconductor pattern is used as a lower electrode of a capacitor C described later. The lower electrodes are arranged corresponding to the pixels PX described later.

  The semiconductor pattern is covered with the gate insulating film GI shown in FIG. The gate insulating film GI can be formed using, for example, TEOS (tetraethyl orthosilicate).

  On the gate insulating film GI, the scanning signal lines SL1 and SL2 shown in FIG. 4 are formed. The scanning signal lines SL1 and SL2 extend in the X direction along the row of the pixels PX, and are alternately arranged in the Y direction along the column of the pixels PX. The scanning signal lines SL1 and SL2 are made of, for example, MoW. The Z direction is a direction perpendicular to the X direction and the Y direction.

  An upper electrode of the capacitor C is further disposed on the gate insulating film GI. The upper electrode is arranged corresponding to the pixel PX and faces the lower electrode of the capacitor C. The upper electrode is made of, for example, MoW, and can be formed in the same process as the scanning signal lines SL1 and SL2.

  The scanning signal lines SL1 and SL2 intersect the semiconductor layer SC. The intersection of the scanning signal line SL1 and the semiconductor layer SC constitutes the switching transistor SWa shown in FIGS. The intersection between the scanning signal line SL2 and the semiconductor layer SC constitutes the switching transistors SWb and SWc shown in FIG. The lower electrode, the upper electrode, and the insulating film GI interposed therebetween constitute the capacitor C shown in FIG. The upper electrode includes a protrusion protruding from the capacitor C in a direction perpendicular to the Z direction, and the protrusion intersects the semiconductor layer SC. This intersection constitutes the drive transistor DR shown in FIG.

  In this example, the drive transistor DR and the switching transistors SWa to SWc are top-gate p-channel thin film transistors. Further, the part indicated by reference numeral G in FIG. 3 is the gate of the switching transistor SWa.

  The gate insulating film GI, the scanning signal lines SL1 and SL2, and the upper electrode are covered with an interlayer insulating film II shown in FIG. The interlayer insulating film II is made of, for example, silicon oxide deposited by a plasma CVD method.

  On the interlayer insulating film II, the video signal line DL and the power supply line PSL shown in FIG. 4 are formed. As shown in FIG. 4, the video signal lines DL extend in the Y direction and are arranged in the X direction. For example, the power supply line PSL extends in the Y direction and is arranged in the X direction.

  On the interlayer insulating film II, a source electrode SE and a drain electrode DE shown in FIG. 3 are further formed. The source electrode SE and the drain electrode DE connect the elements in each pixel PX.

  The video signal line DL, the power supply line PSL, the source electrode SE, and the drain electrode DE have, for example, a three-layer structure of Mo / Al / Mo. These can be formed in the same process.

  The video signal line DL, the power supply line PSL, the source electrode SE, and the drain electrode DE are covered with a passivation film PS shown in FIG. The passivation film PS is made of, for example, silicon nitride.

  On the passivation film PS, the pixel electrodes PE shown in FIG. 3 are arranged corresponding to the pixels PX. These pixel electrodes PE are light-reflecting back electrodes. Each pixel electrode PE is connected to the drain electrode DE through a contact hole provided in the passivation film PS, and this drain electrode is connected to the drain of the switching transistor SWa.

  A partition insulating layer PI shown in FIG. 3 is further formed on the passivation film PS. In the partition insulating layer PI, a through hole is provided at a position corresponding to the pixel electrode PE, or a slit is provided at a position corresponding to a column formed by the pixel electrode PE. Here, as an example, the partition insulating layer PI is provided with a through hole at a position corresponding to the pixel electrode PE.

  The partition insulating layer PI is, for example, an organic insulating layer. The partition insulating layer PI can be formed using, for example, a photolithography technique.

  An organic layer ORG is formed on each pixel electrode PE. Each layer included in the organic material layer ORG may be patterned corresponding to the pixel PX. Alternatively, each layer included in the organic material layer ORG may be connected between the pixels PX.

  The partition insulating layer PI and the organic layer ORG are covered with the counter electrode CE. In this example, the counter electrode CE is a common electrode shared between the pixels PX. In this example, the counter electrode CE is a visible light transmissive front electrode. The counter electrode CE is electrically connected to an electrode wiring (not shown) formed on the same layer as the video signal line DL through, for example, a contact hole provided in the passivation film PS and the partition insulating layer PI. It is connected. Each organic EL element OLED includes a pixel electrode PE, an organic layer ORG, and a counter electrode CE.

  Each of the pixels PX includes a driving transistor DR, switching transistors SWa to SWc, an organic EL element OLED, and a capacitor C as shown in FIG. As described above, in this example, the drive transistor DR and the switching transistors SWa to SWc are p-channel thin film transistors.

  The drive transistor DR, the switching transistor SWa, and the organic EL element OLED are connected in series in this order between the first power supply terminal ND1 and the second power supply terminal ND2. In this example, the power supply terminal ND1 is a high potential power supply terminal, and the power supply terminal ND2 is a low potential power supply terminal.

  The gate of the switching transistor SWa is connected to the scanning signal line SL1. The switching transistor SWb is connected between the video signal line DL and the drain of the drive transistor DR, and its gate is connected to the scanning signal line SL2. The switching transistor SWc is connected between the drain and gate of the driving transistor DR, and the gate is connected to the scanning signal line SL2.

  The capacitor C is connected between the gate of the driving transistor DR and the constant potential terminal ND1 '. In this example, the constant potential terminal ND1 'is connected to the power supply terminal ND1.

  As shown in FIG. 3, the sealing substrate CS faces the substrate SUB1 with the organic EL element OLED interposed therebetween. The sealing substrate CS is, for example, a glass substrate.

  As described above, the seal layer SS has a frame shape, and is interposed between the array substrate AS and the peripheral portion of the sealing substrate CS. As shown in FIG. 2, the seal layer SS surrounds the pixel group PXG configured by all the pixels PX. As a material of the sealing layer SS, for example, frit glass and an adhesive can be used.

  The video signal line driver XDR and the scanning signal line driver YDR are mounted on the array substrate AS, as shown in FIG. A video signal line DL is connected to the video signal line driver XDR. In this example, a power supply line PSL is further connected to the video signal line driver XDR. The video signal line driver XDR outputs the video signal as a current signal to the video signal line DL and supplies a power supply voltage to the power supply line PSL. Scanning signal lines SL1 and SL2 are connected to the scanning signal line driver YDR. The scanning signal line driver YDR outputs the first and second scanning signals as voltage signals to the scanning signal lines SL1 and SL2, respectively.

  Solar cell SB is visible light transmissive. As shown in FIG. 1, the solar cell SB is located between the display panel DP and the observer. In FIG. 1, the display panel DP has the sealing substrate CS facing the observer.

  As shown in FIG. 5, the solar cell SB includes an insulating substrate SUB2. The insulating substrate SUB2 is a visible light transmissive substrate such as a glass substrate.

  A photovoltaic cell PVC is formed on the insulating substrate SUB2. The photovoltaic cell PVC includes electrodes E1 and E2 and a photovoltaic layer PVL interposed therebetween.

  The electrodes E1 and E2 are visible light transmissive electrodes. Of the electrodes E1 and E2, the electrode closer to the observer, in this example, the electrode E2, is further UV transmissive.

  The photovoltaic layer PVL is a layer that generates an electromotive force when irradiated with ultraviolet rays. The photovoltaic layer PVL is visible light transmissive. As the photovoltaic layer PVL, for example, a laminate of a zinc oxide layer and an aluminum oxide layer formed by a laser vapor deposition method, or a titanium oxide particle layer adsorbing a dye can be used.

  The circularly polarizing plate CP is located between the display panel DP and the solar battery SB. The circularly polarizing plate CP includes, for example, a linearly polarizing plate and a λ / 4 wavelength plate laminated so that the transmission axis and the slow axis form an angle of 45 °. The circularly polarizing plate CP converts, for example, natural light traveling from the solar cell SB toward the display panel DP into left circularly polarized light.

  Each of power storage members EA1 and EA2 is, for example, a secondary battery or a capacitor. Typically, at least one of power storage members EA1 and EA2 is a secondary battery. The electrical energy stored in the power storage members EA1 and EA2 is used to drive other devices included in the display device and / or the electronic device.

  One end of a flexible printed circuit board FPC is connected to the controller CNT. The other end of the flexible printed circuit board FPC is connected to the array substrate AS. The controller CNT is connected to the video signal line driver XDR and the scanning signal line driver YDR via the circuit of the array substrate AS via the circuit of the flexible printed circuit board FPC and the array substrate AS.

  The controller CNT supplies a control signal and electric power for controlling their operations to the video signal line driver XDR and the scanning signal line driver YDR. Further, the controller CNT supplies a video signal to the video signal line driver XDR.

  A solar battery SB and power storage members EA1 and EA2 are further connected to the controller CNT. When the electronic device is used, the controller CNT compares, for example, the output voltages of the power storage members EA1 and EA2, and power for operating the electronic device from the power storage member having a higher output voltage, for example, the display panel DP and the driver XDR. And power for operating the YDR. And controller CNT charges the electrical storage member with a smaller output voltage by connecting with solar cell SB. In addition, when the electronic device is not used, the controller CNT charges both the power storage members EA1 and EA2 by connecting to the solar battery SB, for example. Alternatively, the output voltages of the power storage members EA1 and EA2 are compared, and the power storage members having lower output voltages are sequentially charged. That is, the controller CNT controls charging / discharging of each of the power storage members EA1 and EA2.

  This electronic device can operate for a long time and can easily view images even outdoors. This will be described below.

  FIG. 6 is a diagram schematically illustrating how the ambient light incident on the display device illustrated in FIG. 1 is absorbed by the circularly polarizing plate. In FIG. 6, the circularly polarizing plate CP includes a linearly polarizing plate PL and a λ / 4 wavelength plate RT laminated so that the transmission axis and the slow axis form an angle of 45 °.

  Of the natural light such as sunlight incident on the display device shown in FIG. 1, at least a part of the ultraviolet rays is absorbed by the solar cell SB. Visible light transmitted through the solar cell SB is converted into linearly polarized light by transmitting through the polarizing plate PL. This linearly polarized light is converted into, for example, left circularly polarized light by passing through the λ / 4 wavelength plate RT.

  The pixel electrode PE reflects this left circularly polarized light and converts it into right circularly polarized light. The right circularly polarized light is converted into linearly polarized light having a plane of polarization perpendicular to the previous linearly polarized light by passing through the λ / 4 wavelength plate RT. The polarizing plate PL absorbs this linearly polarized light.

  Therefore, the ambient light does not greatly affect the visibility of the image. Therefore, this electronic device can easily view images even outdoors.

  In this electronic device, as described above, the power storage member EA1 and / or EA2 is charged using the electromotive force generated in the solar battery SB. Therefore, this electronic device can operate for a longer time than when the solar battery SB is omitted.

  In addition, since the solar cell SB is positioned between the circularly polarizing plate CP and the observer, more than the case where the circularly polarizing plate CP is positioned between the solar cell SB and the observer, more Light can be incident on the solar battery SB. Therefore, this electronic device can operate for a longer time than when the circularly polarizing plate CP is positioned between the solar cell SB and the observer.

Various modifications can be made to the organic EL display device.
FIG. 7 is a cross-sectional view schematically showing another example of a structure that can be employed in the organic EL display device shown in FIG. FIG. 8 is a cross-sectional view schematically showing still another example of a structure that can be employed in the organic EL display device shown in FIG.

  In the structure of FIG. 7, the circularly polarizing plate CP is located between the sealing substrate CS and the pixel group PXG. In the structure of FIG. 8, the solar cell SB is used as the sealing substrate CS. The photoelectric conversion cell PVC is located between the insulating substrate SUB2 and the pixel group PXT. As described above, various modifications can be made to the arrangement of the constituent members.

  In this aspect, the top emission type display panel DP is used, but a bottom emission type display panel can also be used. In this case, the display panel DP, the circularly polarizing plate CP, and the solar cell SB are arranged so that the array substrate AS and the circularly polarizing plate CP are positioned between the sealing substrate CS and the solar cell SB.

  Although FIG. 4 shows the display panel DP that writes a current signal as a video signal to the pixel circuit, it is also possible to use a display panel that writes a voltage signal as a video signal to the pixel circuit. 3 and 4 show an active matrix driving display panel, other driving display panels such as a passive matrix driving method and a segment driving method may be used.

1 is a perspective view schematically showing a part of an electronic apparatus equipped with an organic EL display device according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a structure that can be employed in the organic EL display device shown in FIG. 1. Sectional drawing which shows schematically an example of the structure employable for the display panel of the organic electroluminescence display shown in FIG. The top view which shows roughly an example of the structure employable for the display panel of the organic electroluminescence display shown in FIG. Sectional drawing which shows roughly an example of the structure employable for the solar cell of the organic electroluminescence display shown in FIG. The figure which shows a mode that the ambient light which injected into the display apparatus shown in FIG. 1 is absorbed by a circularly-polarizing plate. Sectional drawing which shows schematically the other example of the structure employable for the organic electroluminescence display shown in FIG. Sectional drawing which shows schematically the further another example of the structure employable for the organic electroluminescence display shown in FIG.

Explanation of symbols

  AS ... Array substrate, C ... Capacitor, CE ... Counter electrode, CNT ... Controller, CP ... Circular polarizing plate, CS ... Sealing substrate, DE ... Drain electrode, DL ... Video signal line, DP ... Display panel, DR ... Drive transistor , E1 ... electrode, E2 ... electrode, EA1 ... electric storage member, EA2 ... electric storage member, FPC ... flexible printed circuit board, G ... gate, GI ... gate insulating film, II ... interlayer insulating film, ND1 ... power supply terminal, ND1 '... Constant potential terminal, ND2 ... power supply terminal, OLED ... organic EL element, ORG ... organic layer, PE ... pixel electrode, PI ... partition insulating layer, PL ... linear polarizing plate, PS ... passivation film, PSL ... power supply line, PVC ... light Photovoltaic cell, PVL ... Photovoltaic layer, PX ... Pixel, RT ... λ / 4 wavelength plate, SB ... Solar cell, SC ... Semiconductor layer, SE ... Source electrode, SL1 ... Scanning signal , SL2 ... scanning signal line, SS ... seal layer, SUB1 ... insulating substrate, SUB2 ... insulating substrate, SWa ... switching transistor, SWb ... switching transistor, SWc ... switching transistor, UC ... undercoat layer, XDR ... video signal line driver, YDR: Scanning signal line driver.

Claims (2)

A plurality of pixels each including an organic EL element;
A solar cell located on the viewer side with respect to the plurality of pixels and having visible light transparency;
An organic EL display device comprising: a circularly polarizing plate interposed between the plurality of pixels and the solar cell.   An electronic apparatus comprising: the organic EL display device according to claim 1; and a power storage member that stores electric power generated by the solar cell.

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