JP4400153B2 - Display device, manufacturing method thereof, and electronic apparatus - Google Patents

Description

  The present invention relates to a display device, a manufacturing method thereof, and an electronic apparatus.

In recent years, display devices using liquid crystal display devices (LCDs), organic electroluminescent elements (hereinafter referred to as organic EL elements), and the like have been used in various electronic devices such as cellular phones, computers, electronic notebooks, and portable game machines. Yes. For this reason, the user has more opportunities to view the display screen not only indoors but also outdoors.
At this time, a problem arises when light from the outside enters the display screen. The incident light is reflected on the screen and is visually recognized. Usually, however, light that is much stronger outdoors is incident on the screen and is reflected and enters the user's eyes. As a result, the contrast of the display screen is reduced, making it difficult to see the display.

Here, as an example, consider the case where an organic EL element is used in a display device. Since organic EL elements are self-luminous and have good visibility and fast response speed, display devices using these elements are promising as devices for displaying moving images. However, it is difficult for current organic EL elements to obtain high luminance while ensuring a long life. For this reason, a decrease in visibility due to the influence of light from the outside is inevitable outdoors.
In view of this, a display device having a structure in which a black light absorber is formed on the back side of a substrate has been proposed in order to suppress reflection of external light and improve contrast (see, for example, Patent Document 1).
US Pat. No. 5,986,401

  In the display device described in Patent Document 1, an organic material in which a black pigment such as carbon black is dispersed is used as a light absorber formed on the back surface of the substrate. However, this type of light absorber still has a problem that the effect of reducing the reflectance is not sufficient and the reliability as the light absorber is low. Furthermore, an active matrix display device having a plurality of pixels arranged in a matrix and a control element such as a thin film transistor (hereinafter abbreviated as TFT) for controlling the amount of charge supplied for each pixel. In some cases, aluminum or the like may be used as a low-resistance wiring material. In that case, there is a problem that external light is reflected by the wiring portion made of aluminum, and the contrast is lowered.

  The present invention has been made to solve the above-described problems, and is a display device capable of improving the contrast by reliably suppressing reflection of external light and realizing a highly reliable countermeasure against external light reflection. And it aims at providing the manufacturing method. It is another object of the present invention to provide an electronic device including the display device.

As a result of intensive studies on the countermeasure against external light reflection of the display device, the present inventor has found that a laminated film of an indium tin oxide film (hereinafter abbreviated as ITO) and a titanium (Ti) film suppresses reflection of external light. It has been found that the effect is great, and has reached the configuration of the present invention.
That is, the display device of the present invention includes a light-transmitting substrate, a light emitting element formed on one surface of the substrate, and a surface of the substrate opposite to the side on which the light emitting element is formed. And a low reflection layer made of an ITO film and a Ti film sequentially stacked.
In the display device of the present invention, the reflectance of light from the outside can be greatly reduced by the interaction of the ITO film and the Ti film, including each layer constituting the light emitting element. This reflectance can be appropriately controlled by parameters such as the thickness and refractive index of the ITO film or the thickness of the Ti film. Thereby, a display device with high visibility can be realized even in a place with strong external light such as outdoors. In addition, since the low reflection layer made of the ITO film and the Ti film is made of an inorganic material (metal), a highly reliable low reflection structure can be realized as compared with the one using a black resin. Furthermore, since the low-reflection layer is formed on the back side of the substrate (on the side opposite to the light emitting element), there is no interference with the formation of the light emitting element, and in addition to this, there is no decrease in yield. In the case of the outermost surface, static electricity generated on the back surface of the substrate due to substrate transportation or handling during the manufacturing process can be released, and the TFT on the front surface side of the substrate can be protected. In addition, an effect that electromagnetic noise outside the apparatus can be shielded by the low reflection layer is also obtained.

In the display device of the present invention, a plurality of light emitting elements to be pixels are formed on one surface of the substrate, and the control element for controlling the amount of charge supplied for each pixel is electrically connected to the control element. A configuration in which wiring is further formed may be used.
According to this configuration, for example, the low reflection layer is provided on the back surface of the substrate on which a control element such as a TFT is formed, so that the reflectance of light from the outside is greatly increased by the interaction of the ITO film and the Ti film. Can be reduced.

In the above structure, the wiring may be formed of a transparent conductive film. In that case, as the transparent conductive film, the above ITO, indium zinc oxide (hereinafter referred to as IZO), indium cerium oxide (hereinafter referred to as ICO), gallium zinc oxide (hereinafter referred to as GZO), zinc oxide (Hereinafter referred to as ZnO) can be used.
In the display device of the present invention, the low-reflection layer composed of the ITO film and the Ti film is provided on the surface of the substrate opposite to the side where the light emitting element is formed, so even if the wiring is formed of a transparent conductive film In addition, reflection of external light can be suppressed even at a portion immediately below the wiring.

The thickness of the Ti film constituting the low reflection layer is preferably in the range of 30 nm to 500 nm.
The reason is that when the thickness of the Ti film is smaller than 30 nm, the reflectance of external light increases and cannot be put to practical use. On the other hand, if the thickness of the Ti film is larger than 500 nm, the internal stress of the film increases, which may cause warping of the substrate, peeling of the film, or destruction of the element. Moreover, processing becomes difficult.

On the other hand, the thickness of the ITO film constituting the low reflection layer is desirably in the range of 60 nm to 100 nm.
This is because the reflectance of light in the vicinity of a wavelength of 40 nm can be minimized when the thickness of the ITO film is about 60 nm. In addition, when the thickness of the ITO film is about 100 nm, the reflectance of light near the wavelength of 70 nm can be minimized.

Further, it is desirable that the arithmetic average roughness Ra of the surface of the ITO film constituting the low reflection layer is in the range of 4 nm to 50 nm.
In the display device of the present invention, it is preferable that the surface of the ITO film is crystallized so that the arithmetic average roughness Ra of the surface of the ITO film is 4 nm to 50 nm and not a smooth surface. This is because a further effect of reducing the reflectance can be obtained by not smoothing the surface of the ITO film. This is presumably because the local film thickness of the ITO film varies and the interaction with the Ti film and other films acts on light of various wavelengths. However, if the surface is rougher than this, partial film peeling may occur, which is not preferable. If the surface is smoother than the above, the above effect cannot be obtained sufficiently.

In the display device of the present invention, it is desirable to provide a protective member that covers the low reflective layer.
According to this configuration, since the protective member is provided, for example, the Ti film on the back surface of the substrate is damaged or peeled off due to transport or handling of the substrate during the manufacturing process, and a sufficient reflection reduction effect cannot be obtained. Can be prevented.

The protective member may be bonded to the low reflective layer via an adhesive. Alternatively, when the protective member is made of a thermocompression bonding material, it may be directly bonded onto the low reflection layer.
Since the former method does not ask | require the material of a protection member, the freedom degree of selection of a protection member becomes a high thing. On the other hand, in the latter method, since no adhesive is required, the process can be simplified.

  In the display device of the present invention, an organic EL element can be used as the light emitting element. The low reflective layer of the present invention can be formed at a low temperature without deteriorating characteristics and reliability, and can be formed after element formation even when an element having low heat resistance such as an organic EL element is used. It is particularly effective.

  The method for manufacturing a display device of the present invention includes a step of forming a light emitting element on one surface of a light-transmitting substrate and a step of forming an ITO film on the surface of the substrate opposite to the side on which the light emitting element is formed. And a step of forming a Ti film on the ITO film.

Another display device of the present invention includes a light-transmitting substrate, a light-emitting element that is a pixel formed on one surface of the substrate, a control element that controls the amount of charge supplied to each pixel, and the control element And the wiring includes a low reflection layer made of a Ti film and an ITO film sequentially stacked from the substrate side.
For example, when a substrate including a control element such as a TFT is used, wiring for supplying a charge to the control element is essential on the substrate. If, for example, aluminum (Al), which is a low-resistance material, is used as the wiring material, Al has a high light reflectivity, so that there is a possibility that external light is reflected at the wiring portion. In that respect, according to the display device of the present invention, the wiring itself is configured to include the low reflection layer made of the Ti film and the ITO film sequentially laminated from the substrate side. Reflection is suppressed and a display device with excellent visibility can be obtained.

In this configuration, the thickness of the Ti film is preferably in the range of 30 nm to 500 nm. Moreover, it is desirable that the thickness of the ITO film is in the range of 60 nm to 100 nm. Further, it is desirable that the arithmetic average roughness Ra of the surface of the ITO film is in the range of 4 nm to 50 nm.
These reasons are the same as those formed on the back surface of the substrate.

Moreover, an organic EL element can be used as the light emitting element. In that case, it is desirable that the electrode on the substrate side that constitutes the organic EL element includes a highly reflective material.
According to this configuration, the luminance of light emitted from the organic EL element can be improved, and the display becomes clear.

  In the method for manufacturing a display device of the present invention, a step of forming the light emitting element and the control element on one surface of a light-transmitting substrate, and a Ti film and an ITO film are stacked in this order on the one surface of the substrate. Forming the wiring by patterning the Ti film and the ITO film.

An electronic apparatus according to the present invention includes the display device according to the present invention.
According to this configuration, it is possible to provide an electronic device having a display portion with excellent visibility even in a place with strong external light, for example, outdoors.

[First Embodiment]
A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a plan view showing the overall configuration of an organic EL device as an example of the display device of the present invention, FIG. 2 is a plan view of one pixel of the organic EL device, and FIG. 3 is taken along the line AA ′ in FIG. It is sectional drawing. It should be noted that in all the following drawings, in order to make it easy to see each component, the relationship among the components, such as dimensions and film thickness, is appropriately changed.

First, the overall configuration of the organic EL device of the present embodiment will be described with reference to FIG.
In the organic EL device 1 of this example, pixel electrodes connected to switching TFTs (control elements, not shown) are arranged in a matrix on the substrate 20 on a substrate 20 having electrical insulation and translucency. The pixel portion 3 (inside the one-dot chain line frame in FIG. 1) having a substantially rectangular shape in plan view is formed. The pixel unit 3 includes an actual display area 4 (inside the two-dot chain line frame in FIG. 1) in the center and a dummy area 5 (area between the one-dot chain line and the two-dot chain line) arranged around the actual display area 4. It is divided into and. In the actual display area 4, pixel areas R, G, and B each having a pixel electrode are arranged in a matrix so as to be separated from each other in the vertical direction and the horizontal direction on the paper surface. Further, scanning line driving circuits 80 are arranged on the left and right sides of the actual display area 4 in FIG. 1, while data line driving circuits 93 are arranged above and below the actual display area 4 in FIG. The scanning line driving circuit 80 and the data line driving circuit 93 are arranged at the peripheral edge of the dummy region 5. In FIG. 1, the scanning lines and the data lines are not shown.
Further, an inspection circuit 90 is arranged above the data line driving circuit 93 in FIG. This inspection circuit 90 is a circuit for inspecting the operating state of the organic EL device 1 and includes, for example, inspection information output means (not shown) for outputting the inspection result to the outside, and is displayed during manufacture or at the time of shipment. Equipment quality and defects can be inspected. The inspection circuit 90 is also arranged below the dummy area 5. Further, a driving external substrate 95 is connected to the substrate 20, and the external driving circuit 100 is mounted on the driving external substrate 95.

  FIG. 2 is a plan view showing one pixel of the organic EL device 1. As shown in this figure, the data line 10 and the scanning line 11 are provided so as to intersect with each other, and a switching TFT 12 (hereinafter simply referred to as TFT) is provided in the vicinity of the intersection of the data line 10 and the scanning line 11. It has been. An island-shaped semiconductor layer 13 made of, for example, polycrystalline silicon is formed on the substrate 20, and the TFT 12 is configured by a structure in which the gate electrode 14 extending from the scanning line 11 intersects the semiconductor layer 13 in a plane. . A contact hole 15 is formed at one end of the semiconductor layer 13 forming the source region of the TFT 12, and the source region of the TFT 12 and the data line 10 are electrically connected through the contact hole 15. On the other hand, a contact hole 16 is also formed at the other end of the semiconductor layer 13 forming the drain region of the TFT 12, and the drain region of the TFT 12 and the relay conductive layer 17 are electrically connected via the contact hole 16. The relay conductive layer 17 is formed in the same layer as the data line 10. The relay conductive layer 17 is electrically connected to the pixel electrode 19 through the contact hole 18. With the above configuration, the drain region of the TFT 12 and the pixel electrode 19 are electrically connected via the relay conductive layer 17. Note that the storage capacitor may be formed by arranging the relay conductive layer 17 and the scanning line 11 so as to overlap in a plane. Reference numeral 22 denotes a bank which serves as a so-called weir (partition) for storing a solution serving as a material of the EL layer when an EL layer described later is formed by a droplet discharge method typified by an ink jet method or the like. In the case of the present embodiment, the bank 22 has a two-layer structure of an inorganic material layer 22 </ b> A and an organic material layer 22 </ b> B, and is formed annularly along the periphery of the pixel electrode 19.

Next, the cross-sectional structure of the organic EL device 1 will be described with reference to FIG.
A base insulating film 23 made of, for example, a silicon oxide film is formed on a light-transmitting substrate 20 such as glass, and the TFT 12 is formed on the base insulating film 23. The TFT 12 of this embodiment has an LDD (Lightly Doped Drain) structure, and the semiconductor layer 13 includes a high concentration source region 13a, a low concentration source region 13b, a channel region 13c, a low concentration drain region 13d, and a high concentration drain. Region 13e is formed. A gate insulating film 24 is formed on the semiconductor layer 13, and the gate electrode 14 is disposed in a region facing the channel region 13 c with the gate insulating film 24 interposed therebetween. A first interlayer insulating film 25 is formed so as to cover the gate electrode 14 and the scanning line 11, and the data line 10 and the relay conductive layer 17 are formed on the first interlayer insulating film 25. The data line 10 is connected to the high concentration source region 13 a of the semiconductor layer 13 through a contact hole 15 that penetrates the first interlayer insulating film 25 and the gate insulating film 24. On the other hand, the relay conductive layer 17 is connected to the high concentration drain region 13 e of the semiconductor layer 13 through a contact hole 16 penetrating the first interlayer insulating film 25 and the gate insulating film 24. In the case of the present embodiment, the wiring such as the scanning line 11 and the data line 10, the gate electrode 14, and the relay conductive layer 17 are formed of a transparent conductive film such as ITO, IZO, ICO, GZO, ZnO.

  A second interlayer insulating film 26 having a planarized surface is formed so as to cover the data line 10 and the relay conductive layer 17, and the pixel electrode 19 is formed on the second interlayer insulating film 26. The pixel electrode 19 is connected to the relay conductive layer 17 through a contact hole 18 that penetrates the second interlayer insulating film 26. In the case of the present embodiment, the pixel electrode 19 is formed of a transparent conductive film such as ITO, IZO, ICO, GZO, ZnO, and functions as an anode for injecting holes into an EL layer described later. An inorganic material layer 22A and an organic material layer 22B are formed along the peripheral edge of the pixel electrode 19, and a bank 22 is constituted by the two layers of the inorganic material layer 22A and the organic material layer 22B. An EL layer 27 constituting an organic EL element (light emitting element) is formed at the center of the pixel electrode 19 partitioned by the bank 22. In the present embodiment, the EL layer 27 is composed of two layers, for example, a hole injection (transport) layer 27A made of a thiophene-based conductive polymer and a light emitting layer 27B made of a light emitting polymer (LEP). As the structure of the EL layer 27, a structure in which a hole (electron) injection layer and a transport layer are separately provided, a structure including three layers of an electron injection layer, a hole injection layer, and a light emitting layer are applied. Also good.

  A conductive film 28 made of a transparent conductive film such as ITO, IZO, ICO, GZO, or ZnO is provided so as to cover the EL layer 27. In the case of the present embodiment, the conductive film 28 functions as a cathode for injecting electrons into the EL layer 27. Here, when ITO is used, since the numerical value of the work function is relatively high, for example, a layer in which cesium is added to BCP (basocpurine) or a layer in which magnesium and silver are vapor-deposited is provided at the interface between the EL layer 27 and the conductive film 28. Then, it becomes easy to inject electrons. Note that the light emission control of the EL layer 27 of each pixel is performed by the amount of charge supplied to the pixel electrode 19 via the TFT 12 of each pixel, and therefore the conductive film 28 does not need to be individually formed for each pixel. It may be formed over the pixels. Further, a sealing layer 29 is provided to prevent moisture and the like from entering the EL layer 27.

  On the other hand, a low-reflection layer 31 having a two-layer structure in which an ITO film 31A and a Ti film 31B are sequentially stacked from the substrate 20 side is provided on the back side of the substrate 20 (the side opposite to the side where the organic EL element 50 is formed). Is formed. The thickness of the ITO film 31A is preferably in the range of 60 nm to 100 nm. This is because when the film thickness of the ITO film 31A is within this range, a low reflectance can be obtained over almost the visible light region. The thickness of the Ti film 31B is desirably in the range of 30 nm to 500 nm. If the thickness of the Ti film 31B is smaller than 30 nm, the reflectance becomes high and cannot be put to practical use. If the thickness of the Ti film 31B is larger than 500 nm, the internal stress of the film increases, and the substrate 20 This is because there is a risk of causing warpage or peeling of the film or destroying the element. Furthermore, it is desirable that the arithmetic average roughness Ra of the surface of the ITO film 31A be in the range of 4 nm to 50 nm. This is because a further effect of reducing the reflectance can be obtained by roughening the surface of the ITO film 31A to this extent.

Hereinafter, a method for manufacturing the organic EL device 1 having the above configuration will be described.
First, after a base insulating film 23 made of a silicon oxide film having a thickness of about 200 to 500 nm is formed on one surface of the substrate 20 by a plasma CVD method or the like, amorphous silicon having a thickness of about 30 to 70 nm is formed on the base insulating film 23. A semiconductor layer made of a film is formed by a plasma CVD method or the like. Next, the semiconductor layer is crystallized by laser annealing or the like, so that the semiconductor layer is a polycrystalline silicon film. Next, after patterning the semiconductor layer to form the island-shaped semiconductor layer 13, a gate insulating film 24 made of a silicon oxide film having a thickness of about 60 to 150 nm is formed by a plasma CVD method or the like. Next, after forming a transparent conductive film such as ITO by a sputtering method or the like, this is patterned to form the scanning line 11 and the gate electrode 14. Then, source / drain regions are formed in a self-aligned manner by ion implantation using the gate electrode 14 as a mask.

  Next, a first interlayer insulating film 25 is formed, contact holes 15 and 16 reaching the source / drain regions of the semiconductor layer 13 are formed, and then a transparent conductive film such as ITO is formed by sputtering or the like. The data line 10 and the relay conductive layer 17 are formed by patterning. Next, after forming the second interlayer insulating film 26 and forming the contact hole 18 reaching the relay conductive layer 17, a transparent conductive film such as ITO is formed by sputtering or the like, and this is patterned to form the pixel electrode 19. Form. Next, an inorganic material film 22A is formed by plasma CVD or the like and patterned, and then an organic material film 22B is formed in a predetermined pattern to form a bank 22. The organic material film 22B can be formed by a photolithography method, a printing method, or the like.

Next, a solution containing a polymer organic compound is ejected to a region partitioned by the bank 22 using a droplet ejection method such as an ink jet method, and the EL layer 27 (hole injection transport layer 27A and light emitting layer 27B). Form. In forming the EL layer 27, filling and drying of the solution containing the organic compound material are repeated for each layer. After the EL layer 27 is formed, a conductive film 28 made of ITO or the like is formed on the entire surface of the pixel portion 3 by a sputtering method or the like. Next, a sealing layer 29 made of a transparent resin or a thin layer is formed.
Next, an ITO film 31A having a film thickness of 60 nm to 100 nm is formed on the surface of the substrate 20 opposite to the side on which the organic EL element 50 is formed by sputtering or the like, and then a Ti film 31B having a film thickness of 30 nm to 500 nm. The low reflection layer 31 is formed by forming a film by sputtering, ion beam evaporation or the like. The organic EL device 1 of the present embodiment is completed through the above steps.

According to the organic EL device 1 of the present embodiment, the low reflection layer 31 including the ITO film 31A and the Ti film 31B formed on the back surface side of the substrate including each layer constituting the organic EL element causes the external reflection by the interaction. The light reflectance can be greatly reduced.
The inventor actually prototyped an ITO film having a refractive index of 2.15 with respect to light having a wavelength of 520 nm, a film thickness of 78 nm, and a Ti film with a film thickness of 50 to 500 nm laminated on the back side of the glass substrate, The reflectance with respect to external light was evaluated. The reflectance was measured with the incident angle of external light and the outgoing angle of reflected light in the range of 20 ° to 80 °. As a result, it was confirmed that the reflectance was as low as 20 to 40% over the visible light range of wavelength 400 to 700 nm. As for the thickness of the ITO film, the optimum value varies depending on the absorption target wavelength and the refractive index of the ITO, and the thickness of the Ti film may be any film thickness as long as it can be shielded from light, and good in the range of 50 to 500 nm. It turns out that a result is obtained. Further, when the substrate was visually observed, it was visually recognized as dark orange.
Therefore, by adopting such a low reflection layer, it is possible to realize an organic EL device with high visibility even in places where the outside light is strong such as outdoors.

  Further, since the low reflection layer 31 made of the ITO film 31A and the Ti film 31B is made of an inorganic material (metal), it is possible to realize a low reflection layer with higher reliability than that using a black resin or the like. it can. Furthermore, since the low reflective layer 31 is formed on the back side of the substrate 20 (on the side opposite to the organic EL element 50), it does not interfere with the formation of the organic EL element 50, resulting in no reduction in yield. Thus, when the Ti film 31B is the outermost surface of the substrate 20, static electricity generated on the back surface of the substrate due to substrate transportation or handling during the manufacturing process can be released, and the TFT on the substrate surface side can be protected. You can also. In addition, an effect that the electromagnetic wave noise outside the apparatus can be shielded by the low reflection layer 31 is also obtained.

[Second Embodiment]
The second embodiment of the present invention will be described below with reference to FIG.
FIG. 4 is a cross-sectional view of the organic EL device of the present embodiment (corresponding to FIG. 3 of the first embodiment). The basic configuration of the organic EL device of the present embodiment is exactly the same as that of the first embodiment, except that the configuration around the low reflection layer on the back side of the substrate is slightly different. Therefore, illustration and description of the parts common to the first embodiment are omitted, and only different parts will be described with reference to FIG.

  As shown in FIG. 4, the organic EL device according to the present embodiment has the same configuration of the TFT 12 (control element) and the organic EL element 50 (light emitting element) formed on the substrate surface as in the first embodiment. The configuration of the low reflection layer 31 made of the ITO film 31A and the Ti film 31B on the back surface side of the substrate is exactly the same as that of the first embodiment. A different point is that a protective member 42 made of a glass substrate, a plastic film, or the like is bonded to the outside of the Ti film 31 </ b> B constituting the low reflective layer 31 via an adhesive layer 41.

  Also in the organic EL device of the present embodiment, the reflectance of external light can be greatly reduced by the action of the low reflective layer 31, and high visibility can be obtained with high reliability even in places where the external light is strong. Similar to the first embodiment, there is no decrease in yield due to formation, static electricity generated on the back surface of the substrate can be released, TFT on the substrate surface side can be protected, and electromagnetic noise outside the device can be shielded. An effect is obtained. In addition, in the case of the present embodiment, since the protective member 42 for protecting the low reflection layer 31 is provided, for example, the Ti film 31B on the back surface of the substrate is scratched or peeled off by transporting or handling the substrate during the manufacturing process. Thus, it is possible to prevent problems such as that a sufficient reflection reduction effect cannot be obtained. Moreover, since it is the structure which bonds the protection member 42 through the adhesive bond layer 41, the freedom degree of selection of a protection member becomes a high thing irrespective of the material of a protection member.

[Third Embodiment]
The third embodiment of the present invention will be described below with reference to FIG.
FIG. 5 is a cross-sectional view of the organic EL device of the present embodiment (corresponding to FIG. 3 of the first embodiment). The basic configuration of the organic EL device of the present embodiment is exactly the same as that of the first embodiment, except that the configuration around the low reflection layer on the back side of the substrate is slightly different. Accordingly, illustration and description of the parts common to the first embodiment are omitted, and only different parts will be described with reference to FIG.

  As shown in FIG. 5, the organic EL device according to the present embodiment has the same configuration of the TFT 12 (control element) and the organic EL element 50 (light emitting element) formed on the substrate surface as in the first embodiment. The configuration of the low reflection layer 31 made of the ITO film 31A and the Ti film 31B on the back surface side of the substrate is exactly the same as that of the first embodiment. The difference is that a protective member 43 made of a plastic film having thermocompression bonding is directly bonded to the outside of the Ti film 31B constituting the low reflective layer 31.

  Also in the organic EL device of the present embodiment, the reflectance of external light can be greatly reduced by the action of the low reflective layer 31, and high visibility can be obtained with high reliability even in places where the external light is strong. Similar to the first embodiment, there is no decrease in yield due to formation, static electricity generated on the back surface of the substrate can be released, TFT on the substrate surface side can be protected, and electromagnetic noise outside the device can be shielded. An effect is obtained. Further, since the protective member 43 is provided, for example, the Ti film 31B on the back surface of the substrate is scratched or peeled off due to transport or handling of the substrate during the manufacturing process, and a sufficient reflection reduction effect cannot be obtained. The same effect as that of the second embodiment can be obtained. In the case of this embodiment, unlike the second embodiment, since the thermocompression-bonding plastic film is directly bonded, an adhesive is not required, and the protective member is easily bonded.

[Fourth Embodiment]
The fourth embodiment of the present invention will be described below with reference to FIG.
FIG. 5 is a cross-sectional view of the organic EL device of the present embodiment (corresponding to FIG. 3 of the first embodiment). The basic configuration of the organic EL device of this embodiment is exactly the same as that of the first embodiment, except for the configuration of the wiring and electrode portions. Therefore, illustration and description of the parts common to the first embodiment are omitted, and only different parts will be described with reference to FIG.

  In the organic EL device of this embodiment, as shown in FIG. 6, the configuration of the low reflection layer 31 composed of the ITO film 31A and the Ti film 31B on the back side of the substrate is exactly the same as that of the first embodiment. The configuration of the TFT 12 (control element) and the organic EL element 50 (light emitting element) on the substrate surface side is substantially the same as that of the first embodiment, but the configuration of wiring and pixel electrodes is different. That is, the gate electrode 14 (not shown in FIG. 6 but the scanning line is the same) is formed of an aluminum (Al) film 45, and a low reflection layer 46 similar to that on the back side of the substrate is formed on the Al film 45, that is, Ti. The film 46B and the ITO film 46A are laminated in this order from the Al film 45 side. Further, the data line 10 and the relay conductive layer 17 have the same configuration as the gate electrode 14, and a low reflection layer 46 composed of a Ti film 46 B and an ITO film 46 A is laminated on the Al film 45. On the other hand, the pixel electrode 19 has a two-layer structure in which an Al film 47 and an ITO film 48 are laminated from the substrate 20 side.

  In the case of the active matrix display device as in this embodiment, Al, which is a low resistance material, is often used as a wiring material. However, since Al has a high light reflectivity, there is a possibility that external light is reflected at the wiring portion when the low reflection layer is formed on the back side of the substrate, and visibility is lowered. In that respect, according to the organic EL device of the present embodiment, the wiring such as the scanning line 11 and the data line 10 includes the low reflection layer 46 composed of the Ti film 46B and the ITO film 46A. Even in the portion, reflection of external light is suppressed, and an organic EL device having excellent visibility can be obtained. Further, since the pixel electrode 19 is composed of the Al film 47 and the ITO film 48 which are high reflectivity materials, the luminance of light emitted from the substrate surface can be improved, and the display becomes clearer.

[Electronics]
Hereinafter, specific examples of the electronic device including the display device of the present invention will be described.
FIG. 7 is a perspective view showing an example of a mobile phone.
In FIG. 7, reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a display unit using the organic EL device of the above embodiment.
Since the electronic device illustrated in FIG. 7 includes a display portion using the above-described organic EL device, an electronic device capable of displaying with excellent visibility even in a place with strong external light such as outdoors can be realized. .

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, specific descriptions of the material, film thickness, planar shape, and the like of each layer exemplified in the above embodiment can be changed as appropriate. Further, as an example of a display device, an active matrix type example using a TFT as a switching element has been given. However, an active matrix type display device and a passive matrix type display device using a thin film diode (TFD) as a switching element are given. But it ’s okay. Furthermore, not only the organic EL device but also the present invention can be applied to other display devices.

1 is an overall configuration diagram of an organic EL device according to a first embodiment of the present invention. 2 is a plan view showing the configuration of one pixel of the organic EL device. FIG. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is sectional drawing of the organic electroluminescent apparatus of the 2nd Embodiment of this invention. It is sectional drawing of the organic electroluminescent apparatus of the 3rd Embodiment of this invention. It is sectional drawing of the organic electroluminescent apparatus of the 4th Embodiment of this invention. It is a perspective view which shows an example of the electronic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Organic EL device (display device), 10 ... Data line, 11 ... Scanning line, 12 ... Switching TFT (control element), 14 ... Gate electrode, 17 ... Relay conductive layer, 19 ... Pixel electrode, 20 ... Substrate 31 ... Low reflective layer, 31A ... ITO film, 31B ... Ti film, 41 ... Adhesive layer, 42, 43 ... Protective member, 50 ... Organic EL element (light emitting element)

Claims (20)

A substrate having translucency, a light emitting element formed on one surface of the substrate, and an indium tin oxide film sequentially stacked from the substrate side on the surface of the substrate opposite to the side on which the light emitting element is formed And a low reflection layer made of a titanium film , wherein light emitted from the light emitting element is emitted from one side of the substrate .   A plurality of light emitting elements to be pixels are formed on one surface of the substrate, and a control element for controlling the amount of charge supplied for each pixel and a wiring electrically connected to the control element are further formed. The display device according to claim 1.   The display device according to claim 2, wherein the wiring is made of a transparent conductive film.   The display device according to claim 3, wherein the transparent conductive film is made of any one of indium tin oxide, indium zinc oxide, indium cerium oxide, gallium zinc oxide, and zinc oxide.   5. The display device according to claim 1, wherein a film thickness of the titanium film constituting the low reflection layer is in a range of 30 nm to 500 nm.   The display device according to claim 1, wherein a film thickness of the indium tin oxide film constituting the low reflection layer is in a range of 60 nm to 100 nm.   The display device according to claim 1, wherein an arithmetic average roughness Ra of a surface of the indium tin oxide film constituting the low reflection layer is in a range of 4 nm to 50 nm.   The display device according to claim 1, further comprising a protective member that covers the low-reflection layer.   The display device according to claim 8, wherein the protective member is bonded to the low reflective layer via an adhesive.   The display device according to claim 8, wherein the protective member is made of a thermocompression bonding material and is directly bonded onto the low reflective layer.   The display device according to claim 1, wherein the light emitting element is an organic EL element. A light-transmitting substrate; a light-emitting element that is a pixel formed on one surface of the substrate; a control element that controls the amount of charge supplied to each pixel; and a wiring electrically connected to the control element. With
Display the wiring are sequentially low reflection layer viewed including having a layered titanium film and an indium tin oxide film from the substrate side, light emitted from the light emitting element, characterized in that it is emitted from one surface of the substrate apparatus.   The display device according to claim 12, wherein a thickness of the titanium film constituting the low reflection layer is in a range of 30 nm to 500 nm.   14. The display device according to claim 12, wherein a film thickness of the indium tin oxide film constituting the low reflection layer is in a range of 60 nm to 100 nm.   The display device according to claim 12, wherein an arithmetic average roughness Ra of a surface of the indium tin oxide film constituting the low reflection layer is in a range of 4 nm to 50 nm.   The display device according to claim 12, wherein the light emitting element is an organic EL element. The display device according to claim 16, wherein the substrate-side electrode constituting the organic EL element includes an aluminum film .   An electronic apparatus comprising the display device according to claim 1. A manufacturing method of a display device according to claim 1,
Forming a light emitting element on one surface of a light-transmitting substrate; forming an indium tin oxide film on a surface of the substrate opposite to the side on which the light emitting element is formed; and on the indium tin oxide film And a step of forming a titanium film on the display device. It is a manufacturing method of the display device according to claim 12,
A step of forming the light emitting element and the control element on one surface of a light-transmitting substrate; and a titanium film and an indium tin oxide film are stacked in this order on the one surface of the substrate. Forming the wiring by patterning, and a method for manufacturing a display device.

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