Abstract:
Disclosed herein is a light-emitting panel including: an organic electroluminescence element adapted to emit electroluminescence light toward a transparent substrate; a pixel circuit formed on the transparent substrate and adapted to drive the organic electroluminescence element; a color filter formed not only between the transparent substrate and organic electroluminescence element but also immediately on or above the pixel circuit; and a conductive layer formed between the pixel circuit and color filter, the conductive layer being more conductive than the color filter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/439,001, filed Apr. 4, 2012, which claims priority to Japanese Patent Application No. 2011-087417, filed in the Japan Patent Office on Apr. 11, 2011, the entire disclosures of which are hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to a light-emitting panel having an organic EL (electro luminescence) element, a display device having the same light-emitting panel and electronic equipment having the same display device. 
     Recent years have seen the development of current-driven optical elements such as organic EL elements for use as a light-emitting element of a pixel and efforts undertaken to make them commercially available in the field of display devices adapted to display an image (refer, for example, to Japanese Patent Laid-Open No. 2008-083272). The emission brightness of these current-driven optical elements changes according to the current flowing therethrough. Organic EL elements are self-luminous unlike liquid crystal elements. This eliminates the need for a display device using organic EL elements (organic EL display device) to have a light source (backlight), thus providing higher image visibility, lower power consumption and faster element response than liquid crystal display devices for which a light source is necessary. 
     Organic EL display devices are classified into two types, passive matrix and active matrix display devices, depending on a driving method thereof, just as are liquid crystal display devices. The former is simpler in structure. However, it is difficult for this type of organic EL display device to grow into a large-size and high definition display device. Today, therefore, increasing efforts are being made to develop active matrix models. This type of display device is designed to control the current flowing through the light-emitting element provided in each of the pixels using active elements (commonly TFTs (Thin Film Transistors) provided in a drive circuit that is provided for each of the light-emitting elements. 
     SUMMARY 
     Incidentally, the structure adapted to extract EL light can be classified into two types, bottom emission and top emission structures. With the former or bottom emission structure, a color filter is formed on TFT circuitry. However, the color filter becomes charged when it receives EL light from the organic EL element, thus changing the TFT characteristic because of the charge collected on the color filter. 
     For example, it is clear as illustrated in  FIG. 16  that the TFT characteristic of an n-channel transistor with a color filter, provided thereon or thereabove, irradiated with EL light is different from that with no color filter near the n-channel transistor. More specifically, the TFT threshold voltage has moved in the negative direction, with a greater leak current in the OFF condition. If a TFT whose characteristic has undergone such a change is used as a write transistor, the charge held by the holding capacitor in the pixel circuit leaks during the light emission period, thus resulting in lower brightness. 
     The present disclosure has been made in light of the foregoing, and it is desirable to provide a light-emitting panel that can reduce the change in characteristic of the pixel circuit caused by the charging of the color filter, a display device having the same light-emitting panel and electronic equipment having the same display device. 
     A light-emitting panel according to an embodiment of the present disclosure includes an organic EL element, pixel circuit, color filter and conductive layer in each pixel. Here, the organic EL element emits EL light toward a transparent substrate. The pixel circuit drives the organic EL element and is formed on the transparent substrate. The color filter is formed not only between the transparent substrate and organic EL element but also immediately on or above the pixel circuit. The conductive layer is made of a material more conductive than the color filter and formed between the pixel circuit and color filter. 
     A display device according to the embodiment of the present disclosure includes the above light-emitting panel as a display panel and further includes a drive circuit adapted to drive the display panel. Electronic equipment according to the embodiment of the present disclosure includes the above display device. 
     In the light-emitting panel, display device and electronic equipment according to the embodiment of the present disclosure, the conductive layer more conductive than the color filter is formed between the pixel circuit and color filter in the bottom emission light-emitting panel. This reduces the tendency of the pixel circuit to be affected by the charging of the color filter as a result of the reception of EL light emitted from the organic EL element. 
     In the present disclosure, the pixel circuit includes, for example, a holding capacitor, and first and second transistors. The first transistor writes a predetermined voltage to the holding capacitor. The second transistor drives the organic EL element based on the voltage of the holding capacitor. If the pixel circuit is configured as described above, and if the color filter is formed immediately on or above the first transistor, it is preferred that the conductive layer should be formed between the first transistor and color filter. 
     Further, in the present disclosure, the first transistor includes, for example, a gate, source, drain and channel. If the first transistor is configured as described above, it is preferred that the conductive layer should cover part of the channel of all the region of the first transistor opposed to the color filter. Still further, it is more preferred that the conductive layer should cover at least the terminal, i.e., the channel, source or drain, which is externally supplied with a signal because this makes the pixel circuit less affected by the charging of the color filter. 
     Still further, in the present disclosure, the first transistor may be insulated from the conductive layer by an insulating layer for isolation. Alternatively, in the present disclosure, the conductive layer may electrically float. Still alternatively, the conductive layer may be electrically connected to a conductive member different from the conductive layer so as to assume a predetermined potential. 
     In the light-emitting panel, display device and electronic equipment according to the embodiment of the present disclosure, the conductive layer more conductive than the color filter is formed between the pixel circuit and color filter, thus reducing the change in characteristic of the pixel circuit caused by the charging of the color filter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a display device according to an embodiment of the present disclosure; 
         FIG. 2  is a circuit diagram of a subpixel shown in  FIG. 1 ; 
         FIG. 3  is a layout of the components of the subpixel shown in  FIG. 1 ; 
         FIG. 4  is a diagram illustrating an example of cross-sectional structure of the subpixel shown in  FIG. 3  as seen in the direction of arrow A-A; 
         FIG. 5  is a diagram illustrating an example of cross-sectional structure of the subpixel shown in  FIG. 3  as seen in the direction of arrow B-B; 
         FIGS. 6A to 6E  are diagrams illustrating examples of waveforms in relation to the subpixel shown in  FIG. 2 ; 
         FIG. 7  is a diagram illustrating another example of the cross-sectional structure of the subpixel shown in  FIG. 3  as seen in the direction of arrow A-A; 
         FIG. 8  is a plan view illustrating the schematic configuration of a module including the display device according to a modification example of the embodiment; 
         FIG. 9  is a perspective view illustrating the appearance of application example 1 of the display device according to the embodiment and modification example thereof; 
         FIG. 10A  is a perspective view illustrating the appearance of application example 2 as seen from the front, and  10 B is a perspective view illustrating the appearance thereof as seen from the back; 
         FIG. 11  is a perspective view illustrating the appearance of application example 3; 
         FIG. 12  is a perspective view illustrating the appearance of application example 4; 
         FIG. 13A  is a front view of application example 5 in an open position,  FIG. 13B  is a side view thereof,  FIG. 13C  is a front view in a closed position,  FIG. 13D  is a left side view,  FIG. 13E  is a right side view,  FIG. 13F  is a top view, and  FIG. 13G  is a bottom view; 
         FIG. 14  is a diagram illustrating an example of cross-sectional structure of the portion of a subpixel in related art equivalent to that along line A-A shown in  FIG. 3 ; 
         FIG. 15  is a diagram illustrating another example of the cross-sectional structure of the portion of the subpixel in related art equivalent to that along line A-A shown in  FIG. 3 ; and 
         FIG. 16  is a characteristic diagram for describing the change in characteristic of an organic EL element caused by the charging of a color filter. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A detailed description will be given below of the preferred embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that the description will be given in the following order. 
     1. Embodiment 
     Example in which a conductive layer is provided immediately on or above the pixel circuit 
     2. Module and Application Examples 
     &lt;1. Embodiment&gt; 
     [Configuration] 
       FIG. 1  illustrates an example of overall structure of a display device  1  according to an embodiment of the present disclosure. The display device  1  includes a display panel  10  and drive circuit  20  adapted to drive the display panel  10 . 
     The display panel  10  has a display region  10 A in which a plurality of display pixels  14  are arranged two-dimensionally. The display panel  10  displays an image based on an eternally fed video signal  20 A by active matrix driving of each of the display pixels  14 . Each of the display pixels  14  includes a red subpixel  13 R, green subpixel  13 G and blue subpixel  13 B. It should be noted that the subpixels  13 R,  13 G and  13 B are collectively referred to as the subpixels  13  in the description given below. 
       FIG. 2  illustrates an example of circuit configuration of the subpixel  13 . The subpixel  13  includes an organic EL element  11  and pixel circuit  12  adapted to drive the organic EL element  11  as illustrated in  FIG. 2 . It should be noted that an organic EL element  11 R adapted to emit red EL light is provided as an organic EL element in the subpixel  13 R. Similarly, an organic EL element  11 G adapted to emit green EL light is provided as an organic EL element in the subpixel  13 G, and an organic EL element  11 B adapted to emit blue EL light is provided as an organic EL element in the subpixel  13 B. 
     The pixel circuit  12  is, for example, a two-transistor/one-capacitor (2Tr1C) circuit including a write transistor Tws, drive transistor Tdr and holding capacitor Cs. It should be noted that the pixel circuit  12  is not limited to a two-transistor/one-capacitor circuit. Alternatively, the pixel circuit  12  may include two write transistors Tws that are connected to each other in series. Still alternatively, the pixel circuit  12  may include transistors or capacitors different from the above. 
     The write transistor Tws writes a voltage commensurate with the video signal  20 A to the holding capacitor Cs. The drive transistor Tdr drives the organic EL element  11  based on the voltage of the holding capacitor Cs written by the write transistor Tws. The write transistor Tws and drive transistor Tdr include, for example, n-channel MOS (Metal Oxide Semiconductor) thin film transistors (TFTs). It should be noted that the write transistor Tws and drive transistor Tdr may include p-channel MOS TFTs. 
     It should be noted that the write transistor Tws according to the present embodiment corresponds to a specific example of a “first transistor,” and that the drive transistor according to the present embodiment corresponds to a specific example of a “second transistor.” Further, the holding capacitor Cs corresponds to a specific example of a “holding capacitor.” 
     The drive circuit  20  includes a timing generation circuit  21 , video signal processing circuit  22 , data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25 . The drive circuit  20  also includes data lines DTL, gate lines WSL and drain lines DSL. Each of the data lines DTL is connected to one of the outputs of the data line drive circuit  23 . Each of the gate lines WSL is connected to one of the outputs of the gate line drive circuit  24 . Each of the drain lines DSL is connected to one of the outputs of the drain line drive circuit  25 . The drive circuit  20  still further includes a ground line GND (refer to  FIG. 2 ) that is connected to the cathode of the organic EL element  11 . It should be noted that the ground line GND is connected to the ground and assumes the ground voltage when connected to the ground. 
     The timing generation circuit  21  controls the data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25 , for example, so that these circuits operate in concert with each other. The timing generation circuit  21  outputs a control signal  21 A to these circuits, for example, in response to (in synchronism with) an externally fed synchronizing signal  20 B. 
     The video signal processing circuit  22 , for example, corrects the externally fed digital video signal  20 A, converts the corrected video signal into an analog signal and outputs a resultant signal voltage  22 B to the data line drive circuit  23 . 
     The data line drive circuit  23  writes the signal voltage  22 B fed from the video signal processing circuit  22  to the selected display pixel  14  (or subpixel  13 ) via the data line DTL in response to (in synchronism with) the input of the control signal  21 A. The data line drive circuit  23  can output, for example, two voltages, i.e., the signal voltage  22 B and a constant voltage irrelevant to the video signal. 
     The gate line drive circuit  24  applies a selection pulse to the plurality of gate lines WSL one after another in response to (in synchronism with) the input of the control signal  21 A, thus selecting the plurality of display pixels  14  (or subpixels  13 ) on the gate line WSL-by-gate line WSL basis. The gate line drive circuit  24  can output, for example, two voltages, i.e., a voltage applied to turn ON the write transistor Tws and another applied to turn OFF the write transistor Tws. 
     The drain line drive circuit  25  outputs a predetermined voltage to the drain of the drive transistor of each of the pixel circuits  12  via the drain line DSL in response to (in synchronism with) the input of the control signal  21 A. The drain line drive circuit  25  can output, for example, two voltages, i.e., a voltage applied to cause the organic EL element  11  to emit light and another applied to cause the organic EL element  11  to stop emitting light. 
     A description will be given next of the connection between the components and their layout with reference to  FIGS. 2 and 3 . It should be noted that  FIG. 3  illustrates an example of layout of the components of the subpixel  13 . 
     Each of the gate lines WSL is formed to extend in the row direction and connected to a gate  31 A of the write transistor Tws via a contact  37 A. Each of the drain lines DSL is also formed to extend in the row direction and connected to a drain  32 C of the drive transistor Tdr via contacts  37 B. Each of the data lines DTL is formed to extend in the column direction and connected to a drain  31 C of the write transistor Tws via contacts  37 C. 
     A source  31 B of the write transistor Tws is connected to a gate  32 A of the drive transistor Tdr and one end (terminal  33 A) of the holding capacitor Cs via contacts  37 D. A source  32 B of the drive transistor Tdr and the other end (terminal  33 B) of the holding capacitor Cs are connected to an anode  35 A of the organic EL element  11  via contacts  37 E. An organic layer  35 C of the organic EL element  11  is arranged in a region on the anode  35 A and not opposed to the write transistor Tws or drive transistor Tdr. A cathode  35 B of the organic EL element  11  is arranged on an organic layer  35 C and connected to the ground line GND. The cathode  35 B is formed, for example, over the entire surface of the display region  10 A. 
     A description will be given next of the cross-sectional structure of the write transistor Tws and the region close thereto in the display panel  10 .  FIG. 4  illustrates an example of cross-sectional structure of the subpixel  13  shown in  FIG. 3  as seen in the direction of arrow A-A. The display panel  10  includes, for example, the write transistor Tws, holding capacitor Cs and data line DTL in the write transistor Tws and the region close thereto on a substrate  41  as illustrated in  FIG. 4 . The display panel  10  has, for example, a gate insulating layer  42 , insulating layers  43  and  44 , conductive layer  45 , color filter  46 , insulating layers  47  and  48 , the cathode  35 B, an insulating layer  49  and substrate  50  stacked in this order from the side of the substrate  41  in the write transistor Tws and the region close thereto as illustrated in  FIG. 4 . 
     The insulating layer  43  has openings  43 A, and the display panel  10  has the contact  37 C or  37 D in each of the openings  43 A. The display panel  10  has a drain lead-out electrode  31 E immediately on the contacts  37 C. The drain lead-out electrode  31 E is electrically connected to the data line DTL and drain  31 C via the contacts  37 C. Further, the display panel  10  has a source lead-out electrode  31 F immediately on the contacts  37 D. The source lead-out electrode  31 F is electrically connected to the source  31 B and the terminal  33 A of the holding capacitor Cs via the contacts  37 D. 
     The insulating layer  44  fully covers the drain lead-out electrode  31 E, source lead-out electrode  31 F and insulating layer  43 , insulating these electrodes and the conductive layer  45  from each other. The conductive layer  45  is made of a material more conductive than the color filter  46 . The conductive layer  45  is made of a transparent conductive material such as ITO (Indium Tin Oxide). If made of a transparent conductive material, the conductive layer  45  can be formed in the openings of the subpixel  13 . It should be noted that the conductive layer  45  may be made, for example, of a metallic material. In this case, however, it is preferred that the conductive layer  45  should be formed only immediately above the write transistor Tws (or drain lead-out electrode  31 E and source lead-out electrode  31 F) in such a manner as to avoid the openings of the subpixel  13  as illustrated in  FIG. 3 . 
     The conductive layer  45  covers, for example, at least a channel  31 D of the write transistor Tws of all the region of the write transistor Tws opposed to the color filter  46  as illustrated in  FIG. 4 . It is preferred that the conductive layer  45  should cover, for example, at least the source lead-out electrode  31 F, i.e., the terminal on the opposite side of that externally supplied with a signal, of all the region of the write transistor Tws opposed to the color filter  46 , i.e., the channel  31 D, drain lead-out electrode  31 E and source lead-out electrode  31 F, as illustrated in  FIG. 4 . The conductive layer  45  is, for example, not connected to any other conductive member and, therefore, electrically floats. It should be noted that the conductive layer  45  need not necessarily electrically float. Instead, the conductive layer  45  may be, for example, electrically connected to a conductive member different from the conductive layer  45  and, therefore, assume a predetermined potential. 
     The color filter  46 , for example, fully covers the subpixel  13  as illustrated in  FIG. 3 . The color filter  46  is formed not only between the substrate  41  and organic EL element  11  but also immediately above the pixel circuit  12 . The color filter  46  is also formed, for example, immediately above the write transistor Tws as illustrated in  FIG. 4 . In the present embodiment, however, the conductive layer  45  is provided between the color filter  46  and write transistor Tws. Therefore, even if the color filter  46  becomes charged as a result of reception of EL light from the organic EL element  11 , the pixel circuit  12  (especially, the write transistor Tws) does not readily become affected by the charging of the color filter  46 . 
     A description will be given next of the cross-sectional structure of the drive transistor Tdr and the region close thereto in the display panel  10 .  FIG. 5  illustrates an example of cross-sectional structure of the subpixel  13  shown in  FIG. 3  as seen in the direction of arrow B-B. The display panel  10  includes the drive transistor Tdr, holding capacitor Cs and data line DTL in the drive transistor Tdr and the region close thereto on the substrate  41  as illustrated in  FIG. 4 . The display panel  10  has, for example, the gate insulating layer  42 , insulating layers  43  and  44 , color filter  46 , insulating layers  47  and  48 , organic EL element  11 , insulating layer  49  and substrate  50  stacked in this order from the side of the substrate  41  in the drive transistor Tdr and the region close thereto as illustrated in  FIG. 5 . 
     The insulating layer  43  has the opening  43 A, and the display panel  10  has the contact  37 C in the opening  43 A. Although not shown, the display panel  10  has a drain lead-out electrode immediately on the contacts  37 B (refer to  FIG. 3 ). The drain lead-out electrode is electrically connected to the drain  32 C of the drive transistor Tdr via the contacts  37 B. Further, the display panel  10  has a source lead-out electrode  32 E immediately on the contacts  37 E (refer to  FIG. 3 ). The source lead-out electrode  32 E is electrically connected to the source  32 B of the drive transistor Tdr via the contacts  37 E. 
     The anode  35 A of the organic EL element  11  is connected to the source lead-out electrode  32 E via the insulating layer  47  and an opening  47 A formed in the color filter  46 . The anode  35 A has a flat region formed on the flat surface of the insulating layer  47 , and the organic layer  35 C is formed in contact with the flat region of the anode  35 A. The cathode  35 B is formed at least in contact with the top surface of the organic layer  35 C and serves, for example, as a common electrode formed over the entire surface including the organic layer  35 C and insulating layer  48 . 
     Here, the substrate  41  includes, for example, a substrate transparent to EL light such as glass or resin substrate. The substrate  50  includes, for example, a glass, silicon (Si) or resin substrate. The anode  35 A is made of a conductive material transparent to visible light such as ITO. The organic layer  35 C includes, for example, a hole injection layer, hole transport layer, light-emitting layer and electron transport layer that are stacked in this order from the side of the anode  35 A. The hole injection layer provides enhanced hole injection efficiency. The hole transport layer provides enhanced hole transport efficiency to the light-emitting layer. The light-emitting layer emits light as a result of the recombination of electrons and holes. The electron transport layer provides enhanced electron transport efficiency to the light-emitting layer. The cathode  35 B is made of a metallic material and serves as a reflecting mirror. This ensures that light emitted from the organic layer  35 C of the organic EL element  11  is externally output via the anode  35 A, insulating layer  48 , color filter  46 , insulating layers  44 ,  43  and  42  and substrate  41 . Therefore, the rear side of the substrate  41  (side opposite to that on which the drive transistor Tdr is provided) serves as a video display surface S. As a result, the display panel  10  has a bottom emission structure. 
     [Operation] 
     A description will be given next of an example of operation of the display device  1  according to the present embodiment. 
     In this display device  1 , the signal voltage  22 B commensurate with the video signal  20 A is applied to each of the data lines DTL by the data line drive circuit  23 . At the same time, a selection pulse commensurate with the control signal  21 A is applied to the plurality of gate lines WSL and drain lines DSL by the gate line drive circuit  24  and drain line drive circuit  25  one after another. Practically, a picture is displayed as a result of the operation described below. 
       FIGS. 6A to 6E  illustrate examples of waveforms of the voltages applied to the pixel circuit  12  and examples of changes in a gate voltage Vg and source voltage Vs of the drive transistor Tdr.  FIG. 6A  illustrates a signal voltage Vsig and offset voltage Vofs applied to the data line DTL.  FIG. 6B  illustrates voltages Von and Voff applied to the gate line WSL. The voltage Von turns ON the write transistor Tws, and the voltage Voff turns OFF the write transistor Tws.  FIG. 6C  illustrates voltages Vcc and Vini applied to the drain line DSL. Further,  FIGS. 6D and 6E  illustrate the moment-to-moment changes in the gate voltage Vg and source voltage Vs of the drive transistor Tdr in response to the application of the voltages to the drain line DSL, data line DTL and gate line WSL. 
     (Preparation Period for Threshold Correction) 
     First, preparations are made for the threshold correction. More specifically, when the voltage of the gate line WSL is at Voff, and that of the drain line DSL is at Vcc (that is, when the organic EL element  11  emits light), the drain line drive circuit  25  brings the voltage of the drain line DSL from Vcc down to Vini (T1). As a result, the source voltage Vs drops to Vini, causing the organic EL element  11  to stop emitting light. Then, when the voltage of the data line DTL is at Vofs, the gate line drive circuit  24  brings the voltage of the gate line WSL from Voff up to Von, changing the gate voltage of the drive transistor Tdr to Vofs. 
     (First Threshold Correction Period) 
     Next, the threshold correction is performed. More specifically, when the write transistor Tws is ON, and the voltage of the data line DTL is at Vofs, the drain line drive circuit  25  brings the voltage of the drain line DSL from Vini up to Vcc (T2). As a result, a current Ids flows from the drain to source of the drive transistor Tdr, thus raising the source voltage Vs. Then, before the data line drive circuit  23  changes the voltage of the data line DTL from Vofs to Vsig, the gate line drive circuit  24  brings the voltage of the gate line WSL from Von down to Voff (T3). This causes the gate of the drive transistor Tdr to float, thus causing the threshold correction to pause. 
     (First Pause Period of the Threshold Correction) 
     During a pause period of the threshold correction, for example, the voltage of the data line DTL is sampled in a row different from that (pixel) which underwent the threshold correction. It should be noted that, at this time, the source voltage Vs is lower than Vofs-Vth (where Vth is the threshold voltage of the drive transistor Tdr) in the row (pixel) which underwent the threshold correction. During a pause period of the threshold correction, therefore, the current Ids flows from the drain to source of the drive transistor Tdr in the row (pixel) which underwent the threshold correction, thus raising not only the source voltage Vs but also the gate voltage Vg because of the coupling via the holding capacitor Cs. 
     (Second Threshold Correction Period) 
     Next, the threshold correction is performed again. More specifically, when the pixel circuit  12  is ready for threshold correction because the voltage of the data line DTL is at Vofs, the gate line drive circuit  24  brings the voltage of the gate line WSL from Voff up to Von, changing the gate voltage of the drive transistor Tdr to Vofs (T4). At this time, if the source voltage Vs is lower than Vofs-Vth (if the threshold correction has yet to be complete), the current Ids flows from the drain to source of the drive transistor Tdr until the drive transistor Tdr goes into cutoff (until a gate-to-source voltage Vgs reaches Vth). Then, before the data line drive circuit  23  changes the voltage of the data line DTL from Vofs to Vsig, the gate line drive circuit  24  brings the voltage of the gate line WSL from Von down to Voff (T5). This causes the gate of the drive transistor Tdr to float, thus maintaining the gate-to-source voltage Vgs constant irrespective of the magnitude of the voltage of the data line DTL. 
     It should be noted that if, during the threshold correction period, the holding capacitor Cs is charged to Vth, and therefore, the gate-to-source voltage Vgs reaches Vth, the drive circuit  20  terminates the threshold correction. However, if the gate-to-source voltage Vgs does not reach Vth, the drive circuit  20  repeats the threshold correction and pause until the gate-to-source voltage Vgs reaches Vth. 
     (Writing and Mobility Correction Period) 
     The pause period of the threshold correction is followed by the writing and mobility correction. More specifically, when the voltage of the data line DTL is at Vsig, the gate line drive circuit  24  brings the voltage of the gate line WSL from Voff up to Von (T6), connecting the gate of the drive transistor Tdr to the data line DTL. This brings the gate voltage Vg of the drive transistor Tdr equal to the voltage Vsig of the data line DTL. At this time, the anode voltage of the organic EL element  11  is still smaller than a threshold voltage Vel of the organic EL element  11 . Therefore, the organic EL element  11  is still in cutoff. As a result, the current Ids flows into the element capacitance (not shown) of the organic EL element  11 , thus charging the element capacitance. This raises the source voltage Vs by ΔV, thus bringing the gate-to-source voltage Vgs equal to Vsig+Vth−ΔV before long. The writing and mobility correction are performed at the same time as described above. Here, the greater the mobility of the drive transistor Tdr, the greater ΔV. Therefore, the variation in mobility between the subpixels  13  can be eliminated by reducing the gate-to-source voltage Vgs by ΔV before light emission. 
     (Bootstrapping Period) 
     Finally, the gate line drive circuit  24  brings the voltage of the gate line WSL from Von down to Voff (T7). This causes the gate of the drive transistor Tdr to float, thus causing the current Ids to flow from the drain to source of the drive transistor Tdr and raising the source voltage Vs. As a result, a voltage greater than the threshold voltage Vel is applied to the organic EL element  11 , thus causing the organic EL element  11  to emit light at a desired brightness. 
     As described above, in the display device  1  according to the present embodiment, the pixel circuit  12  is controlled to turn ON and OFF in each of the subpixels  13 . As a result, a drive current is injected into the organic EL element  11  of each of the subpixels  13 . This recombines holes and electrons followed by light emission, after which emitted light is externally extracted. As a result, an image is displayed in the display region  10 A of the display panel  10 . 
     [Effect] 
     A description will be given next of the effect of the display device  1  according to the present embodiment. 
     In general, if the display device is a bottom emission display device for extraction of EL light, a color filter is formed on or above the TFT circuitry. As illustrated in  FIG. 14 , for example, the color filter  46  is directly in contact with the drain lead-out electrode  31 E and source lead-out electrode  31 F. Alternatively, as illustrated in  FIG. 15 , for example, the color filter  46  is in contact with the drain lead-out electrode  31 E and source lead-out electrode  31 F via the thin insulating layer  44 . However, the color filter becomes charged when it receives EL light from the organic EL element, thus changing the TFT characteristic because of the charge collected on the color filter. 
     For example, it is clear as illustrated in  FIG. 16  that the TFT characteristic of an n-channel transistor with a color filter, provided thereon or thereabove, irradiated with EL light is different from that with no color filter near the n-channel transistor. More specifically, the TFT threshold voltage has moved in the negative direction, with a greater leak current in the OFF condition. If a TFT whose characteristic has undergone such a change is used as a write transistor, the charge held by the holding capacitor in the pixel circuit leaks during the light emission period, thus resulting in lower brightness. 
     In the present embodiment, on the other hand, the conductive layer  45  more conductive than the color filter  46  is formed between the pixel circuit  12  and color filter  46  in the bottom emission display panel  10 . This ensures that even if the color filter  46  becomes charged as a result of reception of EL light from the organic EL element  11 , the pixel circuit  12  does not readily become affected by the charging of the color filter  46 . This can reduce the change in characteristic of the write transistor Tws caused by the charging of the color filter  46 . 
     [Modification Example] 
     In the above embodiment, the conductive layer  45  covers at least the channel  31 D of the write transistor Tws of all the region of the write transistor Tws opposed to the color filter  46 . However, the conductive layer  45  need only cover at least part of the channel  31 D of the write transistor Tws of all the region of the write transistor Tws opposed to the color filter  46 . As illustrated in  FIG. 7 , for example, the conductive layer  45  need only cover part of the channel  31 D of all the region of the write transistor Tws opposed to the color filter  46 . Even in such a case, the change in the characteristic of the write transistor Tws caused by the charging of the color filter  46  can be reduced as compared to the absence of the conductive layer  45 . 
     &lt;2. Module and Application Examples&gt; 
     A description will be given below of application examples of the display device  1  described in the above embodiment and modification example. The display device  1  is applicable to electronic equipment across all disciplines adapted to display a video signal fed thereto or generated therein as an image or picture. Among examples of electronic equipment are television set, digital camera, laptop personal computer, personal digital assistance such as mobile phone and video camcorder. 
     [Module] 
     The display device  1  is built into a variety of electronic equipment including application examples 1 to 5 as a module as shown, for example, in  FIG. 8 . This module is manufactured, for example, as follows. That is, a region  210  exposed from a member (not shown) adapted to seal the display panel  10  is provided on one side of a substrate  3 . Then, the interconnects of the timing generation circuit  21 , video signal processing circuit  22 , data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25  are extended to this exposed region  210 , thus forming external connection terminals (not shown). An FPC (flexible printed circuit)  220  adapted to exchange signals may be provided on the external connection terminals. 
     APPLICATION EXAMPLE 1 
       FIG. 9  illustrates the appearance of a television set to which the display device  1  is applied. This television set has, for example, a video display screen section  300  including a front panel  310  and filter glass  320 . The video display screen section  300  includes the display device  1 . 
     APPLICATION EXAMPLE 2 
       FIGS. 10A and 10B  illustrate the appearance of a digital camera to which the display device  1  is applied. This digital camera has, for example, a flash-emitting section  410 , display section  420 , menu switch  430  and shutter button  440 . The display section  420  includes the display device  1 . 
     APPLICATION EXAMPLE 3 
       FIG. 11  illustrates the appearance of a laptop personal computer to which the display device  1  is applied. This laptop personal computer has, for example, a main body  510 , keyboard  520  adapted to be manipulated for entry of text or other information and a display section  530  adapted to display an image. The display section  530  includes the display device  1 . 
     APPLICATION EXAMPLE 4 
       FIG. 12  illustrates the appearance of a video camcorder to which the display device  1  is applied. This video camcorder has, for example, a main body section  610 , lens  620  provided on the front-facing side surface of the main body section  610  to capture the image of the subject, imaging start/stop switch  630  and display section  640 . The display section  640  includes the display device  1 . 
     APPLICATION EXAMPLE 5 
       FIGS. 13A to 13G  illustrate the appearance of a mobile phone to which the display device  1  is applied. This mobile phone is made up, for example, of an upper enclosure  710  and lower enclosure  720  that are connected together with a connecting section (hinge section)  730  and has a display  740 , subdisplay  750 , picture light  760  and camera  770 . The display  740  or subdisplay  750  includes the above display device  1 . 
     Although described above with reference to the preferred embodiment and application examples, the present disclosure is not limited thereto and may be modified in various ways. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof. 
     In the above embodiment and others, for example, a case has been described in which the present disclosure is applied to a display device. However, the present disclosure is applicable, for example, to a lighting device. 
     Further, a case has been described in the above embodiment and others in which the display device is an active matrix display device. However, the configuration of the pixel circuit  12  adapted to achieve active matrix driving is not limited to that described in the present embodiment. Therefore, it is possible to add capacitive elements and transistors to the pixel circuit  12  as necessary. In this case, a necessary drive circuit may be added in addition to the timing generation circuit  21 , video signal processing circuit  22 , data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25  to accommodate the changes made to the pixel circuit  12 . 
     Still further, in the above embodiment and others, the timing generation circuit  21  and video signal processing circuit  22  control the driving performed by the data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25 . However, other circuits may control the driving. On the other hand, the data line drive circuit  23 , gate line drive circuit  24  and drain line drive circuit  25  may be controlled by hardware (circuitry) or software (program). 
     Still further, in the above embodiment and others, a description has been given assuming that the source and drain of the write transistor Tws and those of the drive transistor Tdr are fixed. It is, however, needless to say that the source-drain orientation may be reversed from that described above depending on the current flow direction. 
     Still further, in the above embodiment and others, a description has been given assuming that the write transistor Tws and drive transistor Tdr include n-channel MOS TFTs. However, at least one of the write transistor Tws and drive transistor Tdr may include a p-channel MOS TFT. It should be noted that if the drive transistor Tdr includes a p-channel MOS TFT, the anode  35 A of the organic EL element  11  serves as a cathode, and the cathode  35 B thereof as an anode in the above embodiment and others. Still further, in the above embodiment and others, the write transistor Tws and drive transistor Tdr need not necessarily include amorphous silicon TFTs or micro-silicon TFTs. Instead, the same transistors Tws and Tdr may include low-temperature polysilicon TFTs.