Electro-optical device and electronic apparatus having a concave portion containing device elements

An electro-optical device is provided having high aperture ratio with which it is possible to easily planarize an insulating film stacked over a switching element, a wiring and an insulating film constituting the electro-optical device. The electro-optical device includes a substrate, a switching element, a wiring and an insulating film provided for the substrate. The substrate comprises concave portions corresponding to at least one position of the switching element, the wiring and the insulating film.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to an electro-optical device and also to an electro-optical device provided in an electronic apparatus.

2. Related Art

In recent years, proposals have been made as to a structure in which a planarized interlayer insulating film is provided between a thin film transistor (TFT) and a lower electrode of an organic EL element in an organic active EL emissive device. The organic active EL emissive device comprises a plurality of TFT's and a plurality of organic EL elements driven by the TFT's and arranged corresponding to the TFT's.

FIG. 10illustrates a known example of this type of organic active emissive device.

An organic active emissive device148comprises a thin film transistor (TFT)150on a substrate149, an organic EL element154including a counter electrode151, an organic layer152and a lower electrode153, and an interlayer insulating film155. In addition, the terminal of the TFT150is electrically connected to the lower electrode153of the organic EL element154through a contact hole156made in the interlayer insulating film155such that the TFT150drives the organic EL element154.

The thin film transistor (TFT)150comprises a first transistor (Tr1)157and a second transistor (Tr2)158shown in FIG.11. Moreover, electric current passes through scanning electrode lines (Yj to Yj+n)159, signal electrode lines (Xi to Xi+n)160and common electrode lines (Ci to Ci+n)161such that the organic layers152of the organic EL elements154are driven.

Also, capacitors162are formed between the common electrode lines (Ci to Ci+n)161and the first transistors (Tr1)157, respectively, so as to store electric charges.

The interlayer insulating film155is provided over the thin film transistor (TFT)150and planarized at the surface contacted with the lower electrode153.

In addition, an electro-optical device of active-matrix structure shown inFIG. 12has been proposed as another type of conventional device.

InFIG. 12, an electro-optical device170of a conventional active-matrix structure comprises: a glass substrate171; a first polysilicon layer172as an active layer formed on the surface of the glass substrate171; a gate insulating film173formed by thermally oxidizing the poly-silicon layer172; a second poly-silicon layer174as a gate electrode; a first interlayer insulating film175; a second interlayer insulating film176; a signal electrode line178; a first contact hole179; a second contact hole180; a first pixel electrode181; a second pixel electrode182; and an insulating film183.

In the electro-optical device170of the active-matrix structure, the insulating film183is formed and planarized after laminating the first poly-silicon layer172, the gate insulating film173, the second poly-silicon layer174, the first interlayer insulating film175, the second interlayer insulating film176and the signal electrode line178.

In the above conventional organic active emissive device148, needs to improve the property that insulates the lower electrode153from the scanning electrode line159, the signal electrode line160and the thin film transistor150provided below the interlayer insulating film155in order to prevent faulty luminance of the organic EL element154and defects in the process of forming electrodes. Hence, it has been required to form the interlayer insulating film155that exhibits such sufficient insulating property.

However, it is not easy to planarize the interlayer insulating film155with high precision, and there has been such a problem that faulty luminance of the organic EL element and/or the defects in the process of manufacturing electrodes occur when a sufficient insulating property is not obtained.

Moreover, in the case of the above electro-optical device170of the active-matrix structure of another type of prior art, the insulating film183is formed and planarized after depositing the first pixel electrode181; however, there has been such a problem that it is difficult to planarize the insulating film183to be formed over the first pixel electrode181because the second interlayer insulating film176and the first pixel electrode181have irregularities.

The present invention has been made in light of the above circumstances. One goal of the invention is to provide an electro-optical device having a large aperture ratio, and with which it is possible to easily planarize insulating films laminated over a switching element, a wiring and an insulating film constituting the electro-optical device.

SUMMARY

In order to achieve the above goals, the present invention provides the following means.

In an electro-optical device including a substrate, a switching element, a wiring and an insulating film which are provided over the substrate, the substrate includes a concave portion corresponding to at least one position of the switching element, the wiring and the insulating film.

In this electro-optical device, the substrate includes the concave portion corresponding to at least one position of the switching element, the wiring and the insulating film. Therefore, at least one of the switching element, the wiring and the insulating film is formed inside the concave portion, so that it is possible to easily form at least one of the switching element, the wiring and the insulating film in the concave portion.

Further, the electro-optical device of the present invention is as described above, and at least one of the switching element, the wiring and the insulating film is buried in the concave portion.

In this electro-optical device, at least one of the switching element, the wiring and the insulating film is buried in the concave portion. Therefore, at least one of the switching element, the wiring and the insulating film is buried in the concave portion, so that it is possible to easily bury at least one of the switching element, the wiring an the insulating film in the concave portion.

Further, the electro-optical device of the present invention is as described above, and a laminated member including at least one of the switching element, the wiring and the insulating film is buried in the concave portion.

In this electro-optical device, the laminated member including at least one of the switching element, the wiring and the insulating film is buried in the concave portion. Therefore, the laminated member including at least one of the switching element, the wiring and the insulating film is buried in the concave portion, so that it is possible to easily bury the laminated member including at least one of the switching element, the wiring and the insulating film in the concave portion.

In addition, of the switching element, the wiring and the insulating film, that impede light emission of the electro-optical device, the laminated member including at least one of them is buried in the concave portion. Therefore, the light-emitting area in the electro-optical device is enlarged, thereby achieving higher aperture ratio.

Moreover, the electro-optical device of the present invention is as described above, and at least one upper surface of the switching element, the wiring and the insulating film buried in the concave portion is coplanar and contiguous with the upper surface of the substrate.

In this electro-optical device, at least one upper surface of the switching element, the wiring and the insulating film buried in the concave portion is coplanar and contiguous with the upper surface of the substrate. Therefore, a flat insulating film is formed over the substrate and at least one of the switching element, the wiring and the insulating film, and it is possible to easily planarize the insulating film. Moreover, the additional process of planarizing the insulating film can be omitted. Also, when a flat surface with high precision is required on the insulating film, the planarization process with high precision can easily be performed. Moreover, it is possible to easily planarize the boundary insulating film between the pixel electrodes laminated over the insulating film.

Also, fluctuation of the insulating properties of the insulating film is restrained. At the same time, the insulating property of the insulating film can sufficiently be ensured, and the switching characteristics become stable.

Furthermore, the boundary insulating film between the pixel electrodes laminated over the insulating film can easily be planarized, so that it is possible to easily form the banks. It is also possible to prevent faulty luminance of the fluorescent member adjacent to the bank and defects in the process of forming the electrodes.

The electro-optical device of the present invention is as described above, and the boundary insulating film is formed between the first pixel electrode and the second pixel electrode adjacent to the first pixel electrode, so that the upper surface of the boundary insulating film is coplanar and contiguous with the upper surfaces of the pixel electrodes.

In this electro-optical device, the boundary insulating film is formed between the first pixel electrode and the second pixel electrode adjacent to the first pixel electrode, so that the upper surface of the boundary insulating film is coplanar and contiguous with the upper surfaces of the pixel electrodes. Therefore, a flat surface is formed over the pixel electrodes and the boundary insulating film, so that it is possible to easily planarize the upper surfaces of the pixel electrodes. Also, the banks can easily be formed on the pixel electrodes and the boundary insulating film, and it is possible to prevent the faulty luminance of the fluorescent members adjacent to the banks and defects in the process of manufacturing the electrodes. Moreover, when light-emissive layers are formed over the pixel electrodes, the thickness of each of the light-emissive layers is made uniform, thereby preventing unevenness in light-emission.

Furthermore, since the boundary insulating film is formed between the pixel electrode and the adjacent pixel electrode, the pixel electrode can be electrically insulated from the adjacent pixel electrode.

Also, the electro-optical device of the present invention is as described above, and the plurality of bar-like banks are formed extending in a predetermined direction over the pixel electrodes, and end banks extending in the direction intersecting with the bar-like banks are connected to the both ends of the bar-like banks. Also, the fluorescent member is provided in each of the spaces formed by the bar-like banks and the end banks.

In this electro-optical device, the plurality of bar-like banks are formed extending in the predetermined direction over the pixel electrodes, and the end banks extending in the direction intersecting with the bar-like banks are connected to the both ends of the bar-like banks. Moreover, the spaces formed by the bar-like banks and the end banks are provided with the fluorescent members, respectively. Therefore, the fluorescent members surrounded by the bar-like banks and the end banks constitute a rectangle column of pixels of the same color, thereby improving the aperture ratio of the electro-optical device.

Also, dimensional high precision is unnecessary for the width of the boundary insulating film provided below the bar-like bank, so that an electro-optical device can easily be formed.

Furthermore, when the solution of hole injection material or the solution of the light-emitting polymer is applied to the spaces formed by the bar-like banks and the end banks by a droplet-discharging method, highly precise alignment is unnecessary in the extending direction of the bar-like bank, thereby simplifying the process. Moreover, it is possible to improve the yield and prevent pixel defects. Evenness of the film thickness can further be improved.

Moreover, an electronic apparatus of the present invention comprises the above described electro-optical device.

According to the present invention, an electronic apparatus having desired performance characteristics can be realized.

DETAILED DESCRIPTION

Hereafter, embodiments of the present invention will be explained with reference to the drawings. FIG.1throughFIG. 6illustrate an electro-optical device according to an embodiment of the present invention.FIG. 1is a plan view showing part of the electro-optical device, andFIG. 2is a sectional side elevation taken along A—A shown in FIG.1. FIG.3andFIG. 4are sectional side elevations taken along A—A shown inFIG. 1, illustrating the process of manufacturing the electro-optical device.FIG. 5is a plan view of the electro-optical device, andFIG. 6is a sectional side elevation taken along B—B shown in FIG.5.

As shown inFIG. 1, the electro-optical device1of this embodiment comprises: a substrate2; a switching element5comprised of a first TFT3and a second TFT4installed in the substrate2; a lower electrode7below a retention capacitor6for retaining an image signal; and a first interlayer insulating film9for electrically insulating a common feeder wire8provided above the lower electrode7from the lower electrode7. Here, the substrate2comprises concave portions10,11and12corresponding to the positions of the switching element5, the lower electrode7and the first interlayer insulating film9.

Moreover, the switching element5, the lower electrode7and the first interlayer insulating film9are buried in the concave portions10,11and12.

In addition, and the upper surfaces of source regions15and16and drain regions17and18of the switching element5buried in the concave portion10and11are coplanar and contiguous with the upper surface of the substrate2. Moreover, the upper surface of the lower electrode7buried in the concave portion12is coplanar and contiguous with the bottom surface of the concave portion10corresponding to the source region16.

Also, pixel electrodes20are arranged in a lattice pattern as shown inFIG. 5. Aboundary insulating film24is formed between a first pixel electrode21(20) and a second pixel electrode22(20) adjacent to the first pixel electrode. (Moreover, the upper surfaces of the boundary insulating film24, are coplanar and contiguous with those of the first pixel electrode21(20) and the second pixel electrode22(20).

Also, a bank26is formed over the pixel electrode20. The bank26comprises longitudinal banks28and lateral banks29. A plurality of bar-like longitudinal banks28are formed extending in a longitudinal direction regarding a pixel area27, and lateral banks29are connected to both ends of the longitudinal banks28, extending in a direction intersecting with the longitudinal banks28. The spaces formed by the longitudinal banks28and the lateral banks29are provided with fluorescent members30, respectively, as shown in FIG.6.

A scanning signal is supplied to a gate electrode35of the first TFT3from a wiring (a gate line)36.

The retention capacitor6retains potential of an image signal, which is supplied to the retention capacitor6through the source region15and the drain region17of the first TFT3connected to a data line37.

The image signal retained by the retention capacitor6is supplied to a gate electrode38of the second TFT4.

The pixel electrode20receives electric current supplied from the source region16and the drain region18of the second TFT4connected to the common feeder wire8.

In the first TFT3, the gate electrode35is formed as part of the wiring (gate line)36, and the source region15is electrically connected to the data line37through a contact hole40. Moreover, the drain region17is electrically connected to a drain electrode41through a contact hole42.

The drain electrode41is electrically connected to the gate electrode38of the second TFT4and the lower electrode7of the retention capacitor6. The gate electrode38of the second TFT4and the lower electrode7provided in the concave portion12are integrally formed, and the gate electrode38and the drain electrode41are electrically connected to each other through a contact hole44.

In the second TFT4, the source region16is electrically connected to the common feeder wire8through a contact hole45, and the drain region18is electrically connected to the pixel electrode20through a relay electrode49shown inFIG. 2provided in a contact hole46.

Next, the method of manufacturing the electro-optical device1is explained referring with FIG.3and FIG.4.

First of all, the substrate2is etched so as to form the concave portions10(a). The depth of each of the concave portions10from the surface of the substrate2is the same as the thickness of a polysilicon layer51and that of a poly-silicon layer52for the source regions15and16as well as for the drain regions17and18. Subsequently, the substrate2is etched for the second time so as to from the concave portions11of the second step (b). The depth of each of the concave portions11from the surface of the substrate2is the same as the total thickness of the gate electrode35and the poly-silicon layer51thereunder and also as the total thickness of the gate electrode38and the polysilicon layer52thereunder. Moreover, the substrate2is etched for the third time so as to form a concave portion12of the third step (c).

The depth of the concave portion12from the surface of the substrate2is the same as the total thickness of the poly-silicon layer52for the source region16, a gate insulating film55and the lower electrode7.

A base protection film not shown in the figure may be provided on the etched substrate2, as required, by plasma CVD method, using tetraethoxysilane (hereinafter referred to as TEOS) or oxygen as a source gas. On the base protection film, a semiconductor film formed of amorphous silicon is formed by, for example, a plasma CVD method and subsequently crystallized into a poly-silicon film by a crystallization process such as laser annealing or solid phase epitaxy. The poly-silicon film is patterned so as to form the poly-silicon layers51and52, which serve as TFT's. The planarized surfaces are formed such that the upper surfaces of the poly-silicon layers51and52are coplanar and contiguous with the upper surface of the substrate2as shown in (d).

The poly-silicon layers51and52serve as the above source regions15and16, respectively. They also serve as the drain regions17and18, respectively. Next, the gate insulating film55is formed on the surfaces of the poly-silicon layers, using TEOS and oxygen as a source gas as shown in (e).

Subsequently, a conductive film made of a metal film such as aluminum, tantalum, molybdenum, titanium, or tungsten is formed by, for example, a sputtering method and then patterned so as to form the gate electrodes35,38and the lower electrode7. At this time, the wiring (gate line)36shown inFIG. 1is simultaneously formed. In this state, a high concentration of phosphorus ions is implanted such that the source regions and the drain regions are formed with self-alignment toward the gate electrodes35and38as shown in (f). The portion under the gate electrodes35and38where impurities are not doped, become channel regions. Then, after depositing the first interlayer insulating film9, the contact holes40,42,45and46are formed as shown in (g). Subsequently, a conductive film made of a metal film such as aluminum, tantalum, molybdenum, titanium or tungsten is formed by a sputtering method and then patterned so as to form the data line37, the drain electrode41, the common feeder wire8and a lower portion57of the relay electrode49as shown in (h).

Then, the second interlayer insulating film59is formed, and also the contact hole46for the relay electrode49is formed as shown in (i). Thereafter, a conductive film made of a metal film such as aluminum, tantalum, molybdenum, titanium, or tungsten is formed by a sputtering method and then patterned so as to form an upper portion61of the relay electrode49such that a planarized film63is formed as shown in (j). Subsequently, a metal film such as aluminum, tantalum, molybdenum, titanium or tungsten and ITO are laminated and then patterned so as to form the pixel electrode20(k).

Then, the boundary insulating film24is formed between the pixel electrode20and its adjacent pixel, and the upper surface of the boundary insulating film24is coplanar and contiguous with the upper surface of the pixel electrode20as shown in (l). The width of each of the boundary insulating film24thus formed is set to 2 μm, for example.

The parts of the electro-optical device1are formed as described above, so as to provide the pixel area27for the electro-optical device1.

Next, the bank26is formed so as to separate the pixel area27from the fluorescent members30and partition them.

As shown inFIG. 5, the bank26is formed in a stripe pattern. The material of the banks26is polyimide. A space76of the bank26between pixels is 4 μm, the pixel pitch77in the direction parallel to the bank26is 127 μm, the pixel pitch78of the bank26is 43 μm, and the height85of the bank26is 1.7 μm.

Subsequently, the surface of the pixel electrode20is treated by an oxygen plasma process so as to increase the affinity for a fluorescent substance (render the contact angle 20 degrees or less) such as a hole injection material or light-emitting polymer. Then, the affinity of the surface of the bank26for a fluorescent substance such as the hole injection material or the light-emitting polymer is decreased (render the contact angle 50 degrees or more) by freon-plasma process.

Thereafter, the solution of hole injection material is applied to an ellipsoidal shaped column of pixels66, surrounding the pixel electrodes20with the bank26, by droplet-discharging method. The applied solution is then dried by heat treatment and formed as a hole injection layer not shown in the figure. Red, blue and green light-emitting polymer solutions are separately applied on the hole injection layers every one of the columns of pixels66, respectively and dried by heat treatment or by reduced-pressure treatment so as to form light-emissive layers.

Once the light emissive layers are formed, a transparent electrode is formed substantially all over the display region, thereby completing the electro-optical device1. However, the actual device is bonded to a transparent plastic or glass substrate in order to suppress the influence of oxygen and moisture, or may be provided with a SiO2film or an organic thin film.

When the aperture ratio of the electro-optical device of the present embodiment is calculated from the size of each constituent member, it is determined that (43−4)×(127−2)/(127×43)=89.3%, which means that a very high aperture ratio can be obtained.

When the thickness of the hole injection layer and that of the light-emitting polymer layer formed in the above manner are measured, uniformity of the film thickness is improved, compared to the conventional method, both in the direction orthogonal to the banks26and in the direction parallel to the banks26.

The thus formed electro-optical device1comprises: the substrate2; the switching element5comprised of the first TFT3and the second TFT4provided for the substrate2; the lower electrode7below the retention capacitor6for retaining an image signal; and the first interlayer insulating film9for electrically insulating the common feeder wire8provided above the lower electrode7from the lower electrode7as shown in FIG.1. Since the substrate2includes concave portions10,11and12corresponding to the positions of the switching element5, the lower electrode7and the first interlayer insulating film9, the switching element5, the lower electrode7and the first interlayer insulating film9are formed inside the concave portions10,11and12.

Also, the upper surfaces of the source regions15and16and those of the drain regions17and18of the switching element5buried in the concave portions10and11are coplanar and contiguous with the upper surface of the substrate2. Moreover, since the upper surface of the lower electrode7buried in the concave portion12is coplanar and contiguous with the bottom of the concave portion10corresponding to the source region16, the flat second interlayer insulating film59and the pixel electrode20are formed over the substrate2, the switching element5, the lower electrode7and the first interlayer insulating film9.

Also, it is possible to easily planarize the pixel electrode20and the boundary insulating film24laminated above the first interlayer insulating film9and the gate insulating film55.

Furthermore, the pixel electrodes20are arranged in a lattice pattern as shown in FIG.5. The boundary insulating film24is formed between the first pixel electrode21(20) and the second pixel electrode22(20) adjacent to the first pixel electrode21(20). Since the upper surface of the boundary insulating film24is coplanar and contiguous with the upper surfaces of the first pixel electrode21(20) and the second pixel electrode22(20), a flat surface is formed over the boundary insulating film24and the first pixel electrode21(20) and the second pixel electrode2(20). Moreover, the boundary insulating film24is formed between the first pixel electrode21(20) and the second pixel electrode22(20).

Furthermore, the bank26is formed on the pixel electrodes20. The plurality of bar-like longitudinal banks28are formed in the direction longitudinal to the pixel area27, and the lateral banks29are connected to both ends of the longitudinal banks28, extending in the direction intersecting with the longitudinal banks28. Since the fluorescent members30are provided as shown inFIG. 6in the spaces formed by the longitudinal banks28and the lateral banks29, respectively, the fluorescent members30surrounded by the longitudinal banks28and the lateral banks29constitute the rectangle column of pixels66of the same color.

Also, dimensional high precision is unnecessary for the width of the boundary insulating film24below the longitudinal bank28.

Furthermore, when the solution of the hole injection material or the solution of the light-emitting polymer is applied by the droplet-discharging method to the spaces formed by the longitudinal banks28and the lateral banks29, high precision in alignment is unnecessary in the extending direction of the longitudinal banks28.

As described above, the electro-optical device1comprises: the substrate2; the switching element5comprised of the first TFT3and the second TFT4provided for the substrate2; the lower electrode7provided below the retention capacitor6for retaining an image signal; and the first interlayer insulating film9for electrically insulating the lower electrode7from the common feeder wire8provided above the lower electrode7. Since the substrate2comprises concave portions10,11and12corresponding to the positions of the switching element5, the lower electrode7and the first interlayer insulating film9, it is possible to form the switching element5, the lower electrode7and the first interlayer insulating film9in the concave portions10,11and12.

Moreover, since the concave portions are provided, the switching element5, the lower electrode7and the first interlayer insulating film9can readily be buried in those concave portions.

Also, the upper surfaces of the source regions15and16and those of the drain regions17and18of the switching element5buried in the concave portions10and11are coplanar and contiguous with the upper surface of the substrate2. Moreover, the upper surface of the lower electrode7buried in the concave portion12is coplanar and contiguous with the bottom of the concave portion10corresponding to the source region16. Therefore, the flat first interlayer insulating film9and the flat gate insulating film55are formed over the substrate2, the switching element5, the lower electrode7and the first interlayer insulating film9. Consequently, it is possible to easily planarize the first interlayer insulating film9and the gate insulating film55and also to omit an additional process for planarizing the first interlayer insulating film9and the gate insulating film55. Moreover, when a flat surface with high precision is required over the first interlayer insulating film9and the gate insulating film55, it is possible to easily planarize the surface with high precision and also to easily planarize the pixel electrode20and the boundary insulating film24laminated over the first interlayer insulating film9and the gate insulating film55.

Furthermore, it is possible to restrain the fluctuation of the insulating properties of the first interlayer insulating film9and the gate insulating film55and also to prevent the switching characteristics of the switching elements5from varying.

It is also possible to ensure sufficient insulating properties of the first interlayer insulating film9and the gate insulating film55, and thereby the switching characteristics of the switching elements5become stable.

In addition, since it is possible to easily planarize the pixel electrode20and the boundary insulating film such as the boundary insulating film24laminated over the first interlayer insulating film9and the gate insulating film55, the banks26can easily be formed. Also, it is possible to prevent faulty luminance of the fluorescent member30adjacent to the bank26and the defects in the process of manufacturing the electrodes.

Moreover, the pixel electrodes20are formed in a lattice pattern as shown inFIG. 5, and the boundary insulating film24is formed between the first pixel electrode21(20) and the second pixel electrode22(20) adjacent to the first pixel electrode21(20). Moreover, since the upper surface of the boundary insulating film such as the boundary insulating film24is coplanar and contiguous with the upper surfaces of the first pixel electrode21(20) and the second pixel electrode22(20), a flat surface is formed over the boundary insulating film24, and the first pixel electrode21(20) and the second pixel electrode22(20). Therefore, it is easy to planarize the upper surface of the boundary insulating film24and the upper surfaces of the first pixel electrode21(20) and the second pixel electrode22(20). Furthermore, it is possible to easily form the banks26over the boundary insulating film24, the first pixel electrode21(20) and the second pixel electrodes22(20). Also, it is possible to prevent faulty luminance of the fluorescent members30adjacent to the banks26and the defects in the process of manufacturing the electrodes. Moreover, when light-emissive layers are formed on the pixel electrodes, the thickness of each of the light-emissive layers is made uniform, so that unevenness in light emission is prevented.

Also, since the boundary insulating film24is formed between the first pixel electrode21(20) and the second pixel electrode22(20), the fist pixel electrode21(20) can be electrically insulated from the second pixel electrode22(20).

Furthermore, the banks26are formed on the pixel electrodes20. The plurality of bar-like longitudinal banks28are formed extending in the direction longitudinal to the pixel area27, and the lateral banks29are connected to both ends of the longitudinal banks28in the direction intersecting with the longitudinal banks28. Since the spaces formed by the longitudinal banks28and the lateral banks29are provided with the fluorescent members30as shown inFIG. 6, respectively, the fluorescent members30surrounded by the longitudinal banks28and the lateral banks29constitute the rectangle column of pixels66of the same color, so that the aperture ratio of the electro-optical device1can be improved.

Also, high precision is unnecessary for forming the width of the boundary insulating film24provided below the longitudinal bank28, so that the electro-optical device1can easily be formed.

When the solution of the hole injection material or the solution of the light-emitting polymer is applied by the droplet-discharging method to the spaces formed by the longitudinal banks28and the lateral banks29, high precision in alignment is unnecessary in the extending direction of the longitudinal banks28, thereby simplifying the process. Also, yield can be improved, and the defects in the pixels are prevented. Moreover, the film thickness can further be uniform.

The following explains an example of an electronic apparatus provided with the above electro-optical device.

FIG. 7is a perspective view illustrating an example of a cellular phone.FIG. 7illustrates a main body210of the cellular phone and a display portion211using the above organic EL electro-optical device.

FIG. 8is a perspective view illustrating an example of a wristwatch-type electronic apparatus.FIG. 8illustrates a main body220of the watch and a display unit221using the above electro-optical device.

FIG. 9is a perspective view illustrating an example of a mobile information processing apparatus such as a word processor and a personal computer.FIG. 9illustrates an information processing apparatus230, an input unit231such as keyboard, a main body232of the information processing apparatus, and a display unit233using the electro-optical device.

Since the electronic apparatuses shown in FIG.7throughFIG. 9comprise the electro-optical device1of the above embodiment, it is possible to realize the electronic apparatuses which are superior in display quality and provided with the display unit of a bright screen.

The electro-optical device1of the above embodiment comprises: the substrate2; the switching element5comprised of the first TFT3and the second TFT4provided for the substrate2; the lower electrode7provided below the retention capacitor6for retaining an image signal; and the first interlayer insulating film9for electrically insulating the common feeder wire8provided above the lower electrode7from the lower electrode7. In this electro-optical device, the substrate2comprises the concave portions10,11and12corresponding to the positions of the switching element5, the lower electrode7and the first interlayer insulating film9. However, a laminated member including at least one of the switching element5, the lower electrode7and the first interlayer insulating film9may be buried in the concave portions10,11and12.

According to the configuration, the laminated member including at least one of the switching element5, the lower electrode7and the first interlayer insulating film9is buried in the concave portions10,11and12. Further, the laminated member comprising at least one of the switching element5, the lower electrode7and the first interlayer insulating film9impede the light emission of the electro-optical device1, is buried in the concave portions10,11and12. Consequently, the light-emitting area in the electro-optical device1is enlarged, and it is possible to achieve the higher aperture ratio.

Furthermore, in the electro-optical device1, the banks26are formed on the pixel electrodes20, and the plurality of bar-like longitudinal banks28are formed extending in the direction longitudinal to the pixel area27, and the lateral banks29are connected to both ends of the longitudinal banks28in the direction intersecting with the longitudinal banks28. The spaces formed by the longitudinal banks28and the lateral banks29are provided with the fluorescent members30, respectively, as shown in FIG.6. However, depending on the driving method of the electro-optical device1, the fluorescent member30may be provided in each of the spaces formed by the plurality of bar-like banks extending in the direction lateral to the pixel area27and the banks extending in the longitudinal direction at the ends of the bar-like banks.

Moreover, polyimide is employed as the material of the banks26shown inFIG. 5in the above embodiment. However, the material is not limited to polyimide and may be anything as long as the material can be made lyophobic by getting fluorinated by plasma treatment in the atmospheric pressure or in the reduced pressure.

ADVANTAGE OF THE INVENTION

In the electro-optical device as described above, the substrate includes a concave portion corresponding to a location of at least one of the switching element, the wiring and the insulating film. Therefore, at least one of the switching element, the wiring and the insulating film is formed in the concave portion, so that there is an advantage that at least one of the switching element, the wiring and the insulating film can easily be formed inside the concave portion.

Moreover, the laminated member including at least one of the switching element, the wiring and the insulating film is buried in the concave portion. Therefore, the laminated member including at least one of the switching element, the wiring and the insulating film is buried in the concave portion, so that there is an advantage that the laminated member including at least one of the switching element, the wiring and the insulating film can easily be formed in the concave portion.

Also, the laminated member including at least one of the switching element, the wiring and the insulating film impede the light emission of the electro-optical device, is buried in the concave portion, so that there is an advantage that the light-emitting area in the electro-optical device is enlarged, and the aperture ratio is increased.

Furthermore, at least one upper surface of the switching element, the wiring and the insulating film buried in the concave portion is coplanar and contiguous with that of the substrate. Therefore, a flat insulating film is formed over the substrate, the switching element, the wiring and the insulating film, so that there is an advantage that the insulating film can easily be planarized and an additional process of planarizing the insulating film can be omitted. When a flat surface is required on the insulating film, there is an advantage that the film can easily be planarized. It is also advantageous that the boundary insulating film between the pixel electrodes laminated on the insulating film can easily be planarized.

Also, there is an advantage that it is possible to restrain fluctuation of the insulating properties of the insulating film and to prevent the switching characteristics of the switching elements from varying.

Moreover, there is an advantage that the insulating property of the insulating film can be sufficiently ensured, and the switching characteristics become stable.

Since the boundary insulating film between the pixel electrodes laminated on the insulating film can easily be planarized, there is an advantage that the banks can be easily formed. It is also advantageous that it is possible to prevent faulty luminance of the fluorescent members adjacent to the banks and the defects in the process of forming the electrodes.

Furthermore, the boundary insulating film is formed between the first pixel electrode and the second pixel electrode adjacent to the first pixel electrode, and the upper surface of the boundary insulating film is coplanar and contiguous with those of the pixel electrodes. Therefore, a flat surface is formed over the pixel electrodes and the boundary insulating film, so that there is an advantage that the upper surface of the pixel electrode can easily be planarized. Also, there is an advantageous that the banks can easily be formed over the pixel electrodes and the boundary insulating films. Moreover, it is possible to prevent the faulty luminance of the fluorescent members adjacent to the banks and the defects in the process of manufacturing the electrodes, as another advantage. When the light-emissive layers are formed over the pixel electrodes, the thickness of each of the light-emissive layers is advantageously made uniform, thereby preventing unevenness in light emission.

Also, since the boundary insulating film is formed between the pixel electrode and the pixel electrode adjacent to the pixel electrode, the pixel electrode can be electrically insulated from the adjacent pixel electrode as another advantage.

Also, the plurality of bar-like banks are formed extending in the predetermined direction over the pixel electrodes, and the end banks extending in the direction intersecting with the bar-like banks are connected to the both ends of the bar-like banks. Moreover, fluorescent member is provided in each of the spaces formed by the bar-like banks and the end banks. Therefore, the fluorescent members surrounded by the bar-like banks and the end banks constitute a rectangle column of pixels of the same color, so that there is an advantage that the aperture of the electro-optical device is improved.

Also, dimensional high precision is unnecessary for the width of the boundary insulating film provided below the bar-like banks, so that the electro-optical device can easily be manufactured.

When the solution of the hole injection material or the solution of light-emitting polymer is applied to the spaces formed by the bar-like banks and the end banks by the droplet-discharging method, highly precise alignment is not necessary in the extending direction of the bar-like banks, thereby simplifying the process. Also, there is an advantage that it is possible to improve the yield, prevent the pixel defects and enhance uniformity of film thickness.

Moreover, an electronic apparatus having desired performances can advantageously be obtained.

The entire disclosure of Japanese Patent Application No. 2002-140334 filed May 15, 2002 is incorporated by reference.