JP2008034591A - Organic el display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in color purity in an organic EL display for displaying a color picture by allowing light from an organic EL layer for emitting white light to pass through a color filter. <P>SOLUTION: Organic EL layers 4R, 4G, and 4B for emitting white light are formed on a substrate 1 in such a manner that they are separated from one another by a bank 39. For example, white light from the organic EL light emitting layer 4G passes through a green filter 5G and displays green. However, a part of the light proceeds, for example, to a red filter 5R as shown by an arrow. Deterioration in color purity can be prevented by preventing the arrowed light from being emitted to the outside, by entirely reflecting the arrowed light by setting the incident angle C of the arrowed light to a color filter substrate 2 to be equal to or more than a critical angle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic EL display device, in particular, an image display device that performs color display by combining an organic EL that emits white light and a color filter.

  The mainstream of conventional display devices has been CRT, but instead of this, liquid crystal display devices, plasma display devices and the like, which are flat display devices, have been put into practical use, and demand is increasing. Furthermore, in addition to these display devices, display devices using organic electroluminescence (hereinafter referred to as organic EL display devices) and electron sources using field emission are arranged in a matrix to illuminate phosphors arranged on the anode. As a result, display devices that form images (hereinafter referred to as FED display devices) are being developed and put to practical use.

  Since the organic EL display device is (1) self-luminous type compared with liquid crystal, a backlight is not required. (2) The voltage required for light emission is as low as 10 V or less, which may reduce power consumption. (3) Compared with plasma display devices and FED display devices, it does not require a vacuum structure and is suitable for weight reduction and thinning. (4) Response time is as short as a few microseconds and video characteristics are excellent. (5) The viewing angle is as wide as 170 degrees or more.

  An organic EL display device that performs color display generally forms an organic EL layer that emits red, green, and blue light, and performs color display by controlling the brightness of each pixel. In order to increase luminous efficiency, the organic EL light emitting layer often forms an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, and a hole injection layer between the cathode and the anode from the cathode side. There are a type using a low molecular material as an organic EL material and a type using a polymer material. When a low molecular material is used, the organic EL material is deposited by mask vapor deposition, and an organic EL layer is formed on each pixel. In the case of using a polymer material, the organic material is deposited on each pixel by inkjet or the like, and the organic EL layer is deposited on each pixel. In either case, manufacturing becomes difficult when the pixel pitch is reduced.

  On the other hand, a configuration in which color display is performed using a color filter or a color conversion filter using an organic EL material that emits white light has been proposed. “Patent Document 1” discloses a simple matrix type organic EL display device in which an organic EL layer that emits white light is formed on one substrate, and color display is performed using a color conversion filter on the opposite substrate. In “Patent Document 1”, there is a description that an element having a high viewing angle characteristic can be obtained when a gap of 0 to 20 μm exists between the organic EL light emitting element portion and the color conversion filter. There is a description that it is adjusted by the thickness of the gap material used for sealing. However, it is not clear what this viewing angle characteristic means. Further, when the gap of 0 to 20 μm is controlled by the gap material used for sealing, it is not clear what the gap between the organic EL light emitting element part and the color conversion filter will be.

JP 2001-93664 A

  The present invention solves the problem of color mixing of each pixel when a high-definition organic EL display device is realized by combining a color filter used in liquid crystal or the like with an organic EL display device that emits white light.

  That is, as in the conventional case, if a specific color is emitted for each pixel, it is not necessary to consider interference between the specific color and another color. However, when the white light-emitting layer is color-converted by a color filter, when the white light emission reaches another color filter, the color purity is deteriorated by causing a color other than a predetermined color to be developed.

  The present invention uses a color filter using a so-called white-light emitting organic EL, so that in an organic EL display device that performs color display, color purity is deteriorated due to light from a specific pixel entering another color filter. The specific means is as follows.

  (1) Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed across the organic EL layer, and a voltage is applied to the lower electrode and the upper electrode to apply the organic EL An organic EL display device that emits visible light from a layer and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate includes a red filter, a green filter, and a blue filter. And a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. A specific pixel including the organic EL layer is a specific color filter. Correspondingly, the light emitted from the specific pixel is totally reflected by a color filter other than the specific color filter. EL display device.

(2) Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed across the organic EL layer, and a voltage is applied to the lower electrode and the upper electrode to apply the organic EL An organic EL display device that emits visible light from a layer and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate includes a red filter, a green filter, and a blue filter. And a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. A specific pixel including the organic EL layer is a specific color filter. Correspondingly, the organic EL layer of the specific pixel and the organic EL layer of another pixel are separated by a bank, and the organic EL layer of the specific pixel and the specific color filter are separated. The distance D between the data, and the width WBM of the black matrix formed between the color filters, relationships width WBANK of the bank, and the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / D
An organic EL display device characterized by the above.
(3) The organic EL display device according to (2), wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.
(4) The organic EL display device according to (2), wherein the height of the spacer is 1 μm or more.

(5) Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed across the organic EL layer, and a voltage is applied to the lower electrode and the upper electrode to apply the organic EL An organic EL display device that emits visible light from a layer and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate includes a red filter, a green filter, and a blue filter. Formed, a black matrix is formed between the color filters, a spacer is formed between the substrate and the color filter substrate, and a specific pixel including the organic EL layer corresponds to a specific color filter. The organic EL layer of the specific pixel and the organic EL layer of another pixel are separated by a bank, and the substrate and the color filter substrate are separated from each other by the black matrix. There is a deviation of δ in the width direction of the Rix, δ, the distance D between the organic EL layer of the specific pixel and the specific color filter, and the width of the black matrix formed between the color filters The relationship between WBM and the width WBANK of the bank is as follows when the refractive index of the color filter substrate is n.
^{tan (sin - (1 / n} )) ≦ {WBM-δ + (WBANK-WBM) / 2} / D
An organic EL display device characterized by the above.
(6) The organic EL display device according to (5), wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.
(7) The organic EL display device according to (5), wherein the spacer has a height of 1 μm or more.

(8) Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed across the organic EL layer, and a voltage is applied to the lower electrode and the upper electrode to apply the organic EL An organic EL display device that emits visible light from a layer and forms a color image by disposing a color filter substrate facing the substrate, wherein the organic EL layer is formed by an organic EL layer and a bank of another pixel The color filter substrate includes a red filter, a green filter, and a blue filter, a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. The bank width is WBANK, the sum of the bank height and the spacer height is DD, and is formed between the color filters. When the black width of the matrix and WBM, the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / DD
An organic EL display device characterized by the above.
(9) The organic EL display device according to (8), wherein the bank is made of an organic resin.
(10) The organic EL display device according to (8), wherein the bank is formed of an inorganic film.
(11) The organic EL display device according to (8), wherein the spacer has a height of 1 μm or more.
(12) The organic EL display device according to (8), wherein the spacer is formed on a black matrix formed on the color filter substrate.
(13) The organic EL display device according to (8), wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.

(14) Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed across the organic EL layer, and a voltage is applied to the lower electrode and the upper electrode to apply the organic EL An organic EL display device that emits visible light from a layer and forms a color image by disposing a color filter substrate facing the substrate, wherein the organic EL layer is formed of another pixel and an inorganic material Separated by banks, a red filter, a green filter, and a blue filter are formed on the color filter substrate, a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. The height of the spacer is HS, the width of the bank is WBANK, and the black block formed between the color filters is formed. The width of the matrix and WBM, when the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / HS
An organic EL display device characterized by the above.
(15) The organic EL display device according to (14), wherein the spacer has a height of 1 μm or more.
(16) The organic EL display device according to (14), wherein the spacer is formed on a black matrix.

(17) A red filter, a green filter, and a blue filter are formed on the substrate, a black matrix is formed between the filters, and an organic resin film for planarization is formed on the color filter. An inorganic film is formed on the organic resin film, and a layer including a TFT having a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, and a passivation film is formed on the inorganic film. An organic EL layer that emits visible light according to a signal that passes through the layer including the TFT is formed on the including layer, and the organic EL layer is arranged in a matrix to form an image on the substrate. An organic EL display device, wherein each of the organic EL layers is separated by a bank, and the organic EL layer that emits the visible light and the red filter, the green filter, or the blue filter The distance and DF, the width of the black matrix formed between the color filter and WBM, the width of the bank as WBANK, when the refractive index of the substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / DF
Organic EL display that satisfies the above relationship.
(18) The organic EL display device according to (17), wherein the passivation film includes an organic resin film.
(19) The organic EL display device according to (17), wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.
(20) The passivation film includes an organic resin film, and the sum of the thickness of the resin film for planarization and the thickness of the resin film included in the passivation is 3 μm or more. The organic EL display device described.

  The effect of each means is as follows.

  According to the means (1), among the light emitted from the organic EL layer of the specific pixel, the light directed to the color filter other than the corresponding color filter is totally reflected and is not emitted to the outside, thereby preventing a decrease in color purity. be able to.

  According to the means (2) to (4), by providing the conditions that are in the width of the black matrix and the interval between the color filter and the organic EL layer, the light corresponding to the light emitted from the organic EL layer of the specific pixel is handled. Since light directed to the color filters other than the color filter is totally reflected and is not emitted to the outside, it is possible to prevent a decrease in color purity.

  According to the means (5) to (7), even if an alignment error between the substrate and the color filter substrate occurs, all of the light emitted from the organic EL layer of the specific pixel is directed to the color filter other than the corresponding color filter. Since the light is not reflected and emitted to the outside, it is possible to prevent a decrease in color purity.

  According to the means (8) to (13), by giving a certain condition to the relationship between the sum of the bank height and the spacer height and the black matrix width, among the light emitted from the organic EL layer of the specific pixel, Since light directed to a color filter other than the corresponding color filter is totally reflected and is not emitted to the outside, a decrease in color purity can be prevented.

  According to the means (14) to (16), by giving a certain condition to the relationship between the spacer height and the black matrix width, out of the light emitted from the organic EL layer of the specific pixel, the color other than the corresponding color filter Since light directed to the filter is totally reflected and is not emitted to the outside, it is possible to prevent a decrease in color purity and to prevent an organic EL film from being damaged by the color filter.

  According to the means (17) to (20), when the present invention is applied to a bottom emission type organic EL display device, no matter what film is formed between the organic EL film and the substrate surface, If the distance between the organic EL film and the color filter and the BM width are kept in a certain relationship, the light emitted from the organic EL layer of the specific pixel toward the color filter other than the corresponding color filter is totally reflected. And since it does not radiate | emit outside, the fall of color purity can be prevented.

  The detailed contents of the present invention will be disclosed according to the embodiments.

  FIG. 1 is a schematic sectional view of a first embodiment of the present invention, and FIG. 2 is a detailed sectional view thereof. A portion (TFT portion) related to the thin film transistor (TFT) for controlling the voltage applied to the organic EL layer 42 is formed on the glass substrate. A white light emitting unit 4 including a lower electrode 41, an organic EL layer 42, and an upper electrode 43 is formed on the TFT unit 3. In this embodiment, the organic EL display device is a so-called top emission type, and the lower electrode 41 is a cathode. An organic EL layer 42 such as an electron injection layer, an electron transport layer, a white light emitting layer, a hole transport layer, and a hole injection layer is formed in order from the lower electrode 41, and an anode as the upper electrode 43 is formed on the hole injection layer. . Here, white light is visible light including red, green, and blue spectra.

  In this embodiment, the lower electrode 41 needs to include a metal film such as Al that reflects light. The upper electrode 43 needs to be a transparent conductive film such as IZO or ITO that transmits light. As the organic EL material of the white light emitting layer 42, for example, a composite thin film in which TPB, coumarin, and DCM-1 are mixed using polyvinyl carbazole (PVK) as a dopant can be used. TPB, coumarin, and DCM-1 are shown in Formula (1), Formula (2), and Formula (3), respectively.

  In FIG. 1, the color filter substrate 2 is installed through a frame member 7. The frame member 7 keeps the distance between the substrate 1 and the color filter substrate 2. Inside the color filter substrate 2 is formed a color filter portion 5 that receives white light and performs color conversion. Since the distance between the color filter unit 5 and the light emitting unit 4 including the organic EL layer 42 plays an important role in color mixing in the display device in the first embodiment, in this embodiment, the spacer 6 is used to The distance to the light emitting unit 4 is controlled. The light is emitted in the direction of arrow L in FIG.

  FIG. 2 is a detailed sectional view of the present embodiment. In FIG. 2, the substrate 1 uses glass in this embodiment. However, in the case of top emission, the substrate 1 does not need to transmit light, and thus is not limited to glass. A metal such as SUS or a plastic material such as PET or PES can also be used. The undercoat film 31 serves as a barrier against irregular materials from the substrate 1. On the other hand, the adhesion between the undercoat film 31 and the semiconductor layer 32 formed thereon is also important. In this embodiment, a silicon oxide film, a silicon nitride film, or a laminated film thereof is used. When a two-layer film is used as the undercoat film 31, the film thickness is, for example, 150 nm for the lower silicon nitride and 100 nm for the upper silicon oxide.

  As the semiconductor layer 32, an amorphous Si film formed by a CVD method or a polysilicon film formed by annealing an amorphous Si film with a laser is used. On both sides of the semiconductor layer 32, a source portion or a drain portion imparted with conductivity is formed by ion implantation. The film thickness of the semiconductor layer 32 is, for example, 50 nm.

  A gate insulating film 33 is formed so as to cover the semiconductor layer 32. As the gate insulating film 33, silicon oxide or silicon nitride formed by a CVD method or a laminated film thereof is used. The film thickness of the gate insulating film 33 is, for example, 100 nm. A gate metal layer to be the gate electrode 34 is formed on the gate insulating film 33 by sputtering or the like. By patterning this metal layer, not only the gate electrode 34 but also the gate wiring layer is formed. As the gate metal layer, a refractory metal such as Mo, W, Ta, Ti, or an alloy of these metals is suitable. Furthermore, a laminated film of these metals or alloys may be used. When the gate metal layer is also used as the terminal portion, the uppermost layer needs to be made of a stable material such as Ti, TiN, ITO, or IZO. The film thickness of the gate electrode 34 is 150 nm, for example.

  An interlayer insulating film 35 is formed to cover the gate electrode 34. The interlayer insulating film 35 serves to insulate the gate wiring connected to the gate electrode 34 and the signal wiring connected to the SD wiring layer 36. The interlayer insulating film 35 is made of silicon oxide or silicon nitride formed by CVD. The film thickness of the interlayer insulating film 35 is, for example, 500 nm.

  An SD metal layer to be the SD wiring layer 36 is formed by sputtering or the like so as to cover the interlayer insulating film 35. The SD metal layer is patterned to become a signal line, and is connected to the source part or the drain part of the semiconductor layer 32 through a through hole formed in the interlayer insulating layer. A passivation film for protecting the TFT and the like is formed covering the SD wiring layer 36. The passivation film has a two-layer structure. As the lower passivation film 37, an inorganic film such as a SiN film is formed to a thickness of 100 nm to 200 nm. This lower layer film is mainly responsible for the entry of impurities. The upper passivation film 38 is made of, for example, an organic resin such as an acrylic resin with a thickness of about 1 micron or more. This upper passivation film 38 is formed to flatten the surface.

  Then, a wiring layer to be the lower electrode 41 of the organic EL layer 42 is formed on the flat organic passivation film 38. The wiring layer to be the lower electrode 41 is connected to the SD wiring layer 36 through a through hole formed in the passivation film. In the top emission type, the lower electrode 41 needs to have the following characteristics. That is, since it is necessary to reflect the light from the organic EL layer 42, it has sufficient reflectivity and can withstand an etching solution used for etching the lower electrode 41 or the bank 39 formed on the passivation film. That is, it has an electron injection characteristic for the organic EL layer 42.

  After forming the lower electrode 41 of the organic EL film, an acrylic film for forming the bank 39 is coated. This acrylic film is partially removed by etching. The lower electrode 41 of the organic EL film is exposed at the portion where the acrylic film is removed. The remaining portion of the acrylic film becomes a bank 39 for separating pixels. Note that the bank 39 is not limited to an organic film, and may be an inorganic film such as a SiN film.

  An organic EL layer 42 is deposited on the portion where the acrylic film is removed and the lower electrode 41 is exposed. As described above, the organic EL layer 42 is formed of a plurality of films. In FIG. 2, the organic EL layer 42 is separated for each pixel, but is not necessarily separated. This is because the same organic EL layer 42 is formed in any pixel. The white light emission method is advantageous in that it is not necessary to separate the organic EL layer 42.

A transparent conductive film that serves as an anode is formed on the organic EL layer 42. Since the present invention is a top emission type, the upper electrode 43 serving as an anode needs to be a transparent electrode. Further, the upper electrode 43 needs to have a high hole injection efficiency with respect to the organic EL layer 42. Since the upper electrode 43 applies a constant DC voltage to the organic EL layer 42, it does not have to be separated for each pixel. Moreover, since there is an opportunity to be exposed to the outside air, it is necessary to be chemically stable. Furthermore, electrical characteristics such as resistance must be stable over a long period of time. The material of the upper electrode 43 that can be used in this embodiment is ITO, IZO, WO ₃ or the like.

  On the upper electrode 43, the color filter substrate 2 is installed at an appropriate interval. On the color filter substrate 2, red, green and blue color filters and a black matrix (BM) are formed. Although a protective film is formed on the color filter and the BM 51, it is omitted in FIG. A spacer 6 for controlling the interval is formed between the BM 51 and the bank 39. The spacer 6 is formed by photolithography on the BM 51 formed on the color filter substrate 2 and comes into contact with the bank 39 on the substrate 1 side.

  In the configuration as shown in FIG. 2, for example, it is assumed that light emitted from 4G enters the green color filter 5G. The problem here is, for example, the case where the light emitted from 4G enters the red color filter 5R. Light as indicated by the arrows in FIG. 2 will degrade the color purity of green. An object of the present invention is to prevent deterioration of color purity due to light as indicated by an arrow in FIG.

  As long as there is a gap between the upper electrode 43 of the organic EL and the color filter, it is inevitable that light as shown by the arrow in FIG. 2 exists. In the present invention, even if such light is present, the total reflection due to the difference in refractive index is used to prevent the light as shown by the arrow in FIG. It is to prevent.

  FIG. 3 shows a schematic cross-sectional view for explaining the present embodiment. In FIG. 3, the detailed structure is omitted for the sake of simplicity. In FIG. 3, it is assumed that the light emitted from the light emitting unit 4G is incident on the green color filter 5G. However, part of the light goes to other than the green filter. Here, as shown by the arrow, the white light emitted from the end of the light emitting unit 4G reaches the end of the red filter 5R, and the angle with the main surface of the color filter substrate 2 at that time is C. . If the light of this arrow is totally reflected on the glass substrate surface and does not touch the viewer's eyes, the color purity will not deteriorate.

  In order to obtain the total reflection condition, a description will be given with reference to FIG. The light emitted from the light emitting portion 4 of the organic EL is first incident on the filter and refracted, further refracted and incident on the glass substrate, and finally exits from the glass substrate into the air. The angle between the principal surface of each layer and the light beam is as shown as C1, C2, and C3 in FIG. In FIG. 4, it is assumed that the refractive index of the color filter is larger than the refractive index of the color filter substrate 2. As can be seen from FIG. 4, whether or not the light from the light emitting unit 4 is totally reflected at the interface between the color filter substrate 2 and the outside air depends on the size of the angle C1. The angle C1 is the same as the angle C1 incident on the color filter layer. Therefore, whether or not the light is totally reflected may be determined by evaluating the angle C1 at which the light emitted from the light emitting unit 4 enters the color filter substrate 2.

  Here, returning to FIG. 3, a condition for total reflection of light is obtained. The color filter substrate 2 is non-alkali glass and has a refractive index of 1.51 to 1.54. In this case, the critical angle is sin C = 1 / n, and C is 40 degrees to 41 degrees. That is, if the angle C is greater than 41 degrees, the light is totally reflected and the light indicated by the arrow shown in FIG. 3 does not pass through the red filter 5R. Therefore, the color purity does not deteriorate. In FIG. 3, the angle C of the light emitted from the right side of the arrow in the light emitting unit 4G becomes larger. Therefore, if the light of the arrow is totally reflected, the other light is also totally reflected.

  In FIG. 3, it is assumed that the width WBM of the BM 51 is smaller than the width WBANK of the bank 39. In FIG. 3, it is assumed that the alignment accuracy between the substrate 1 and the color filter substrate 2 is perfect. In this case, in FIG. 3, the condition of whether or not the total reflection is performed is as follows. The distance between the light emitting unit 4 and the color filter unit 5 is D, the width of the BM 51 is WBM, and the width of the bank 39 is WBANK. WBM + (WBANK-WBM) / 2} / D. Here, since TanC = 0.87, total reflection occurs and the color purity does not deteriorate if the condition of 0.87D ≦ WBM + (WBANK−WBM) / 2 is satisfied.

  FIG. 5 shows an arrangement example of the color filters of the high-definition organic EL display device. This pixel arrangement has a definition of about 300 dots / inch. Here, one dot means one set of R, G, and B shown in FIG. Assuming that the width WBANK of the bank 39 is the same as the width WBM of the BM 51, 0.87D ≦ 10 μm, and if the distance between the light emitting unit 4 and the color filter is 11 μm or less, the color purity does not deteriorate. It will be.

  Actually, the alignment accuracy between the substrate 1 and the color filter substrate 2 is not perfect, and as shown in FIG. This deviation δ is about 6 μm from the actual results. Based on this, as described above, assuming that the width of the bank 39 and the width of the BM 51 are the same, and evaluating with the pixel arrangement as shown in FIG. 5, 0.87D ≦ (10−6) μm. Therefore, when the value of D is 4.4 μm or less, there is no deterioration in color purity.

  In this case, a spacer 6 is used to control the distance between the light emitting portion 4 and the color filter portion 5, and this spacer 6 is formed on the BM 51 by a photolithography method, for example, in an acrylic columnar shape as shown in FIG. To do. Since the spacer 6 abuts against the bank 39, the height of the spacer 6 is determined by the height HB of the bank 39. When the bank 39 is formed of a resin such as acrylic, it is 1 μm to 2 μm. Therefore, in this case, the height of the spacer 6 is changed from 2.4 μm to 3.4 μm. On the other hand, when the bank 39 is formed of an inorganic film such as SiN, the thickness of the bank 39 is about 0.1 μm.

  If the distance D between the light emitting unit 4 and the color filter unit 5 is, for example, 4.4 μm or less, total reflection occurs, and theoretically, the color purity does not deteriorate. However, in actuality, the color filter has irregularities of up to about 1 micron, and the organic EL film may be destroyed if the irregularities come into contact with the organic EL film of the light emitting portion. In particular, when an inorganic material is used for the bank 39, since the height of the bank 39 is small, the possibility that the color filter contacts the organic EL film of the light emitting portion is very high. Even when the bank 39 is an organic film, the risk of contact between the color filter and the organic EL film of the light emitting portion is great if the height is about 1 μm or less. Thus, in this embodiment, the role of the spacer 6 is great from the viewpoint of protecting the organic EL film of the light emitting portion.

  In FIG. 2, the spacer is a so-called SOC (Spacer On Color Filter) in which acrylic is formed in a columnar shape on the BM 51 of the color filter substrate 2. However, the spacer is not limited to this, and an organic material, as shown in FIG. For example, you may use the spherical thing formed with the acryl.

  As described above, according to this embodiment, the color filter substrate 2 that has already been proven in the liquid crystal display device is used for the organic EL display device, so that it can be mass-produced and the color purity is not deteriorated. An organic EL display device can be realized. The present invention is particularly effective in a high-definition display device having a BM width of 10 μm or less.

  FIG. 8 shows a schematic cross-sectional view of the second embodiment of the present invention. In FIG. 8, a color filter substrate is not separately manufactured, and the color filter portion 5 and the light emitting portion are formed on the same substrate. In FIG. 8, a color filter layer is first formed on a substrate 1. An organic material such as acrylic is formed thereon as a planarizing film. An acrylic film is formed with a thickness of 2 μm for sufficient planarization. An undercoat film 31 is formed on the planarizing film, and the TFT portion 3 is formed. A light emitting part including an organic EL layer is formed on the TFT part 3. The organic EL display device in Example 2 is a bottom emission type, and light is emitted in the direction of arrow L in FIG. In FIG. 8, the back glass plate 200 hermetically seals the inside of the organic EL display device through the frame member 7 and protects the organic EL film from the influence of moisture and the like.

  FIG. 9 is a detailed sectional view of the second embodiment. In FIG. 9, first, the color filter portion 5 is formed on the substrate 1. The color filter unit 5 includes a red filter 5R, a green filter 5G, and a blue filter 5B, and a BM 51 is formed between the filters. On the color filter, a planarizing film is formed with an acrylic resin, for example, with a thickness of about 2 μm or more. An inorganic undercoat film 31 is formed thereon. This inorganic undercoat film 31 has the same role as in the first embodiment. Thereafter, the TFT layer is formed as in the first embodiment.

Since this embodiment is a bottom emission type, the lower electrode 41, the organic EL layer 42, and the upper electrode 43 in FIG. 9 are different from those in the first embodiment. That is, the lower electrode 41 serves as an anode, and a transparent electrode is used. As the material of the transparent electrode, ITO, IZO, WO ₃ or the like is used. Contrary to Example 1, the organic EL layer 42 has a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer deposited from below. As in the first embodiment, an organic EL material that emits white light is used for the light emitting layer. The upper electrode 43 serving as the cathode is made of Al or Al alloy having a high reflectance.

  A rear glass plate 200 for protecting the organic EL layer 42 from moisture and the like is installed on the upper electrode 43, and the rear glass plate 200 airtightly seals the inside of the display device through the frame member 7 in the peripheral portion of the display device. Keep on. Since Example 2 is bottom emission, the member for sealing does not necessarily need to be a transparent member such as a back glass plate, and may be a metal such as a sealing can.

  Also in this case, as in Example 1, when the white light from the light emitting layer enters the other color filter and is emitted to the outside from the crow surface, the color purity is deteriorated. This situation is shown in FIG. In FIG. 10, it is assumed that the white light emitted from the light emitting unit 4R is incident on the red filter 5R, but the light traveling in the oblique direction is incident on the green filter 5G as indicated by an arrow in FIG. Even in such a case, deterioration of color purity can be avoided if the light of the arrow is not totally reflected and emitted from the substrate 1.

  If the conditions under which light is totally reflected are derived in the same way as in the first embodiment, TanC ≦ {WBM + (WBANK−WBM) / 2} / (HTFT + HF). Here, HTFT is the thickness of the entire TFT section 3, and HF is the thickness of the planarizing film. WBM is the width of the BM film, and WBANK is the width of the bank 39. That is, if the incident angle to the color filter is larger than the critical angle C, total reflection occurs, and deterioration of color purity can be avoided.

  A particularly important point of the present invention is that it is difficult for a complex system such as bottom emission in which light from the organic EL layer 42 passes through many layers and is then emitted from the surface of the glass substrate to form an image. However, a condition that does not degrade the color purity can be obtained by the simple formula as described above.

  It should be noted that in this embodiment, when white light from the organic EL layer 42 reaches the semiconductor portion of the TFT, the semiconductor malfunctions due to the light. Therefore, in order to realize the present embodiment, it is necessary to make the semiconductor layer 32 have a structure that shields white light from the organic EL layer 42.

  As described above, when the present invention is used, even when the white light emitting organic EL layer 42 is used in a bottom emission type organic EL display device, it is possible to realize a display device that does not deteriorate the color purity.

  FIG. 11 is a plan view of a substrate 1 of an organic EL display device having pixels constructed according to the present invention. In the first embodiment, a color filter substrate 2 is installed facing the substrate 1. In the second embodiment, after the color filter portion 5 is formed on the substrate 1, the drive portion described below is formed.

  A display area 121 is formed in most of the center of the substrate 1. Scan signal driving circuits 122 and 123 are arranged on both sides of the display area. Gate signal lines extend from the scanning signal drive circuits 122 and 123. The gate signal lines 124 from the left scanning signal driving circuit 122 and the gate signal lines 125 from the right scanning signal driving circuit 123 are alternately arranged.

  A video signal driving circuit 126 is disposed below the display area 121, and a data signal line 127 extends from the data signal driving circuit to the display area 121 side. A current supply bus 128 is disposed above the display area 121, and a current supply line 129 extends from the current supply bus 128 toward the display area 121.

  The data signal lines 127 and the current supply lines 129 are alternately arranged, so that one pixel is formed in each region surrounded by the data signal lines 127, the current supply lines 129, and the gate signal lines 124 and the gate signal lines 125. The PX area is configured. The cross section of the pixel PX is a cross sectional view of the present invention shown in FIG.

  A contact hole group 130 is formed on the upper side of the display area. The contact hole group 130 has a role of electrically connecting the upper electrode 43 of the organic EL layer 42 formed over the entire display region to a wiring formed under the insulating film and extending to the terminal. Terminals 131 are formed below the display area, and scanning signals, data signals, an anode potential, a cathode potential, and the like for the organic EL layer 42 are supplied from these terminals 131.

  A sealing material 71 is formed so as to surround the display area 121, the scanning signal driving circuits 122 and 123, the video signal driving circuit 126, and the current supply bus 128, and a frame for sealing the color filter substrate 2 or the rear glass plate 200 in this portion. The material 7 is sealed. Terminal portions 131 are formed on the substrate 1 outside the sealing material 71, and signals or currents are supplied from these terminals to the scanning signal drive circuits 122 and 123, the video signal drive circuit 126, the current supply bus 128, and the like.

It is a schematic sectional drawing of 1st Example of this invention. It is a detailed sectional view of the pixel portion of the first embodiment of the present invention. It is a cross-sectional schematic diagram explaining 1st Example of this invention. It is auxiliary explanatory drawing of this invention. It is a top view of the pixel part to which this invention is applied. It is a cross-sectional schematic diagram explaining the other form of 1st Example of this invention. It is a cross-sectional schematic diagram explaining the further another form of 1st Example of this invention. It is a schematic sectional drawing of 2nd Example of this invention. It is a detailed sectional view of the pixel portion of the second embodiment of the present invention. It is a cross-sectional schematic diagram explaining 2nd Example of this invention. 1 is an overall plan view of a display device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Color filter board | substrate, 3 ... TFT part, 4 ... Light emission part, 5 ... Color filter part, 6 ... Spacer, 7 ... Frame material, 31 ... Undercoat film, 32 ... Semiconductor layer, 33 ... Gate insulation Film 34... Gate electrode 35. Interlayer insulating film 36 SD wiring layer 37 lower passivation film 38 upper passivation film 39 bank 41 lower electrode 42 organic EL layer 43 upper electrode 51 ... Black matrix, 200 ... Back glass plate, 4R ... Red light emitting part, 4G ... Green light emitting part, 4B ... Blue light emitting part, 5R ... Red filter, 5G ... Green filter, 5B ... Blue filter

Claims (20)

  Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed with the organic EL layer interposed therebetween, and a voltage is applied to the lower electrode and the upper electrode so that the pixel is visible from the organic EL layer. An organic EL display device that emits light and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate is formed with a red filter, a green filter, and a blue filter, A black matrix is formed between the color filters, a spacer is formed between the substrate and the color filter substrate, and a specific pixel including the organic EL layer corresponds to a specific color filter. The light emitted from the specific pixel is configured to be totally reflected by a color filter other than the specific color filter. Display devices. Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed with the organic EL layer interposed therebetween, and a voltage is applied to the lower electrode and the upper electrode so that the pixel is visible from the organic EL layer. An organic EL display device that emits light and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate is formed with a red filter, a green filter, and a blue filter, A black matrix is formed between the color filters, a spacer is formed between the substrate and the color filter substrate, and a specific pixel including the organic EL layer corresponds to a specific color filter. The organic EL layer of the specific pixel and the organic EL layer of another pixel are separated by a bank, and the organic EL layer of the specific pixel, the specific color filter, Distance and D, a width WBM of the black matrix formed between the color filters, relationships width WBANK of the bank, and the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / D
An organic EL display device characterized by the above.   3. The organic EL display device according to claim 2, wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.   The organic EL display device according to claim 2, wherein a height of the spacer is 1 μm or more. Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed with the organic EL layer interposed therebetween, and a voltage is applied to the lower electrode and the upper electrode so that the pixel is visible from the organic EL layer. An organic EL display device that emits light and forms a color image by disposing a color filter substrate facing the substrate, wherein the color filter substrate is formed with a red filter, a green filter, and a blue filter, A black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. A specific pixel including an organic EL layer corresponds to a specific color filter, and the specific filter The organic EL layer of the pixel and the organic EL layer of the other pixel are separated by a bank, and the substrate and the color filter substrate are separated from each other by the black matrix. Of the black matrix formed between the color filters and the distance D between the organic EL layer of the specific pixel and the specific color filter. And the relationship between the bank width WBANK and the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM-δ + (WBANK-WBM) / 2} / D
An organic EL display device characterized by the above.   6. The organic EL display device according to claim 5, wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank.   The organic EL display device according to claim 5, wherein a height of the spacer is 1 μm or more. Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed with the organic EL layer interposed therebetween, and a voltage is applied to the lower electrode and the upper electrode so that the pixel is visible from the organic EL layer. An organic EL display device that emits light and forms a color image by disposing a color filter substrate facing the substrate, wherein the organic EL layer is separated from an organic EL layer of another pixel by a bank, The color filter substrate is formed with a red filter, a green filter, and a blue filter, a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate, The width of the bank is WBANK, the sum of the height of the bank and the height of the spacer is DD, and the bank is formed between the color filters. The width of the black matrix and WBM, when the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / DD
An organic EL display device characterized by the above.   The organic EL display device according to claim 8, wherein the bank is formed of an organic resin.   The organic EL display device according to claim 8, wherein the bank is formed of an inorganic film.   The organic EL display device according to claim 8, wherein the spacer has a height of 1 μm or more.   The organic EL display device according to claim 8, wherein the spacer is formed on a black matrix formed on the filter substrate.   9. The organic EL display device according to claim 8, wherein the width WBM of the black matrix is substantially equal to the width WBANK of the bank. Pixels including an organic EL layer are arranged in a matrix on a substrate, a lower electrode and an upper electrode are formed with the organic EL layer interposed therebetween, and a voltage is applied to the lower electrode and the upper electrode so that the pixel is visible from the organic EL layer. An organic EL display device that emits light and forms a color image by disposing a color filter substrate opposite to the substrate, wherein the organic EL layer is separated from other pixels by a bank formed of an inorganic material. A red filter, a green filter, and a blue filter are formed on the color filter substrate, a black matrix is formed between the color filters, and a spacer is formed between the substrate and the color filter substrate. The height of the spacer is HS, the width of the bank is WBANK, and the black matrix formed between the color filters is formed. Scan width of the WBM, when the refractive index of the color filter substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / HS
An organic EL display device characterized by the above.   The organic EL display device according to claim 14, wherein a height of the spacer is 1 μm or more.   The organic EL display device according to claim 14, wherein the spacer is formed on a black matrix. A red filter, a green filter, and a blue filter are formed on the substrate, a black matrix is formed between the filters, an organic resin film for planarization is formed on the color filter, and the organic An inorganic film is formed on the resin film, and a layer including a TFT having a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, and a passivation film is formed on the inorganic film. An organic EL layer that emits visible light in response to a signal that has passed through the layer including the TFT is formed thereon, and the organic EL layer is arranged in a matrix to form an image on the substrate. A device, wherein each of the organic EL layers is separated by a bank, and the distance between the organic EL layer emitting visible light and the red filter, green filter, or blue filter When the DF, the width of the black matrix formed between the color filter and WBM, the width of the bank and WBANK, the refractive index of the substrate is n,
^{tan (sin - (1 / n} )) ≦ {WBM + (WBANK-WBM) / 2} / DF
Organic EL display that satisfies the above relationship.   The organic EL display device according to claim 17, wherein the passivation film includes an organic resin film.   18. The organic EL display device according to claim 17, wherein a width WBM of the black matrix is substantially equal to a width WBANK of the bank. The organic material according to claim 17, wherein the passivation film includes an organic resin film, and a total thickness of the resin film for the planarization and a resin film included in the passivation is 3 μm or more. EL display device.

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