JP2001290441A - Color display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL display device the deterioration which in an early stage caused by applying an excess current on the color pixels having the lowest light emission efficiency among the display pixels having different light emission efficiencies is prevented and which has a longer life. SOLUTION: The EL device having display pixels of each color arranged in a matrix produced by successively depositing an anode 161, a light emission layer 163 and a cathode 166 is manufactured in such a manner that the light emission area of the green light emission region 1G having the highest light emission efficiency is made smaller compared with the light emission area of the red and blue light emission regions 1R, 1B. Thus, the life of the EL display device is increased and the white balance can be easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-luminous element such as an electroluminescence (hereinafter referred to as "EL") element and a thin film transistor (hereinafter referred to as "TFT"). The present invention relates to a color display device provided.

[0002]

2. Description of the Related Art In recent years, an EL display device using an EL element has attracted attention as a display device replacing a CRT or an LCD.

Further, a display device having a TFT as a switching element for driving the EL element has been researched and developed.

FIG. 7 is a plan view showing the vicinity of a display pixel of an organic EL display device, FIG. 8A is a cross-sectional view taken along the line AA in FIG. 7, and FIG. 7 is a sectional view taken along line BB in FIG.

As shown in FIG. 7, a display pixel is formed in a region surrounded by a gate signal line 51 and a drain signal line 52. A first TFT 30 is provided near the intersection of the two signal lines, and a source 13 s of the TFT 30 has a capacitance electrode 55 forming a capacitance with a storage capacitance electrode line 54 described later.
And is connected to the gate 41 of the second TFT 40. The source 43s of the second TFT is an organic EL
The other drain 43 d is connected to the anode 61 of the element 60.
Are connected to a drive power supply line 53 which is a current source supplied to the organic EL element 60.

A gate signal line 5 is provided near the TFT.
A storage capacitor electrode line 54 is arranged in parallel with the storage capacitor electrode line 1. This storage capacitor electrode line 54 is made of chromium or the like. Also,
The storage capacitor electrode line 54 is formed via the gate insulating film 12 with the capacitor electrode 55 connected to the source 13s of the TFT 30. The charge is accumulated between the storage capacitor electrode line 54 and the capacitor electrode 55 to form a capacitor. This storage capacitor is provided to hold a voltage applied to the gate electrode 41 of the second TFT 40.

As shown in FIG. 8, the organic EL display device is
A TFT and an organic EL element are sequentially laminated on a substrate 10 such as a substrate made of glass or synthetic resin, a conductive substrate, or a semiconductor substrate. However, substrate 1
When a substrate having conductivity and a semiconductor substrate are used as 0, a TFT and an organic EL element are formed on an insulating film such as SiO ₂ or SiN formed on the substrate 10.

First, the first TFT, which is a switching TFT, is used.
The TFT 30 will be described.

As shown in FIG. 8A, a gate electrode 11 made of a high melting point metal such as chromium (Cr) or molybdenum (Mo) is formed on an insulating substrate 10 made of quartz glass, non-alkali glass, or the like. The gate signal line 51 and the storage capacitor electrode line 54 are arranged. Subsequently, the gate insulating film 12,
And polycrystalline silicon (hereinafter, referred to as “p-Si”)
Active layers 13 made of films are sequentially stacked.

An SiO ₂ film and a Si film are formed on the entire surface of the gate insulating film 12, the active layer 13 and the stopper insulating film 14.
An interlayer insulating film 15 laminated in the order of the N film and the SiO ₂ film is formed, and a drain 13 d of the interlayer insulating film 15 is formed.
A drain electrode 16 filled with a metal such as Al is provided in a contact hole formed at a position corresponding to the above, and a flattening insulating film 17 made of an organic resin and flattening the surface is formed on the entire surface of the substrate.

Next, the second TFT 40 which is a TFT for driving the organic EL element will be described.

As shown in FIG. 8 (b), Cr, Cr on an insulating substrate 10 made of quartz glass, non-alkali glass or the like.
A gate electrode 41 made of a refractory metal such as Mo, a gate insulating film 12, and an active layer 43 made of a p-Si film are sequentially formed. The active layer 43 has a channel 43c.
A source 43s and a drain 43d are provided on both sides of the channel 43c. And the gate insulating film 1
On the entire surface of the 2 and the active layer 43, SiO ₂ film, an SiN film is formed and the SiO ₂ film interlayer insulating film 15 which are laminated in this order, the contact hole formed at a position corresponding to the drain 43d of the interlayer insulating film 15 And a driving power supply line 53 filled with a metal such as Al and connected to a driving power supply. Further, a flattening insulating film 17 made of, for example, an organic resin and flattening the surface is provided on the entire surface. Then, a contact hole is formed at a position corresponding to the source 43s of the planarizing insulating film 17 and the interlayer insulating film 15, and the ITO contacted with the source 43s through this contact hole.
(Indium Tin Oxide) transparent electrode, ie, organic EL
An anode 61 of the element is provided on the planarizing insulating film 17.

The organic EL element 60 includes an anode 61 made of a transparent electrode such as ITO, and an MTDATA (4,4,4-tris (3-methy)
a first hole transport layer composed of, for example, lphenylphenylamino) triphenylamine, and TPD (N, N-diphenyl-N, N-di (3-
a second hole transport layer 62 such as methylphenyl) -1,1-biphenyl-4,4-diamine, etc., and a Bebq ₂ (bis (10-hyd) containing a quinacridone derivative.
A light emitting element layer 65 made of a light emitting layer 63 made of, for example, droxybenzo [h] quinolinato) beryllium), a light emitting element layer 65 made of an electron transporting layer 64 made of Bebq ₂ or the like, and a cathode 66 made of a magnesium-indium alloy or the like are stacked in this order. In addition, each pixel is provided with each pixel, and enables light emission in each pixel.

In this organic EL device, the holes injected from the anode and the electrons injected from the cathode are recombined inside the light emitting layer, and excite the organic molecules forming the light emitting layer to generate excitons. Light is emitted from the light emitting layer during the process of radiation deactivation of the excitons, and the light is emitted from the transparent anode to the outside through the transparent insulating substrate to emit light.

[0015]

However, the luminous efficiency of the light emitting layer that emits each color is different for each color.

However, in the conventional EL display device, as shown in FIG. 9, each of the colors (red (R), red (R), Since the light-emitting areas 1B, 1R, and 1G of the display pixels of green (G) and blue (B) are all the same, in order to obtain the same luminance in a display pixel having low light-emitting efficiency, another light-emitting efficiency is required. A larger current must be passed than a good display pixel, which has the disadvantage of shortening the life of the display pixel and shortening the life of the EL display device.

Further, if the light-emitting areas of the display pixels of the respective colors having different luminous efficiencies are the same, it is difficult to obtain a color balance (white balance) due to a difference in chromaticity of each color, and a large current is required to maintain the balance. Therefore, there is a disadvantage that the EL element of the display pixel to which a large amount of current is supplied is deteriorated.

Accordingly, the present invention has been made in view of the above-mentioned conventional disadvantages, and an object of the present invention is to provide a display device having a light-emitting element such as an EL element which can easily control white balance and has a long life. Aim.

[0019]

According to a color display device of the present invention, in a color display device having a self-luminous element in a display pixel, a light emitting area of one of the display pixels of each color is different from that of the other. This is different from the light emitting area of the color display pixel.

The above-described color display device is a color display device in which the light emitting area is set according to the light emitting efficiency of the self light emitting element.

In the above-described color display device, the light-emitting area may be set by setting the luminous efficiency of the self-luminous element provided in the display pixel, the chromaticity of each color emitted by the self-luminous element, and the like. Is a color display device set for each color according to the chromaticity of white.

In the above-described color display device, the light emitting area of the self-luminous element having a high luminous efficiency is smaller than the light emitting area of the self-luminous element having a lower luminous efficiency than the self-luminous element having a high luminous efficiency. Device.

Further, the above-described color display device is a color display device in which the light emitting area of the self light emitting element having the highest light emitting efficiency is smaller than the light emitting area of the self light emitting element having the other light emitting efficiency.

The above-described color display device is a color display device in which the self-luminous element having the highest luminous efficiency is a self-luminous element that emits green light.

Further, the above-described color display device is a color display device in which the light-emitting area of the self-luminous element having the lowest luminous efficiency is larger than the light-emitting area of the self-luminous element having the other luminous efficiency.

In the above-described color display device, the self-luminous element having the lowest luminous efficiency is a self-luminous element that emits red or blue light.

The above-described color display device is a color display device in which the luminous area increases in order as the luminous efficiency decreases.

Further, in the above-described color display device, the self-luminous element is a color display device which is an electroluminescence display device.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An EL display device according to the present invention will be described below.

FIG. 1 is a plan view of an EL display device 100 according to the present invention.

FIG. 2 shows a case where each display pixel emits red (R), green (G) and blue (B) light. FIG. 2 shows a basic plane configuration of each of the R, G, and B display pixels.

In the EL display device 100, a plurality of gate signal lines 51 are provided in a row (left / right) direction, a plurality of drain signal lines 52, and a drive power supply line 53 for supplying power from a power supply to the EL element. The signal lines 51, the signal lines 52, and the driving power supply lines 53 intersect with each other in the column (up / down) direction.

Near these intersections, both signal lines 51, 52
A second TFT 40 that supplies a current from the driving power supply line 53 to the organic EL element 160,
And an organic EL element 1 that emits light of any of R, G, and B
60 are formed. In FIG. 1, R in FIG.
Only the light emitting area of each of the display pixels that emit G and B light is shown (1R, 1B and 1G are added in FIG. 1).

As shown in FIG. 1, the display pixels of each color are arranged in a matrix on the substrate, and the light emitting areas 1R, 1G, and 1B of the display pixels are different from each other. Specifically, in the case of FIG. 1, the light emitting area of the green light emitting region 1G is provided with the smallest light emitting area. The light emitting regions 1R and 1B of other colors are formed in a larger area than the green light emitting region 1G. That is, in the case of the figure, the light emitting area of the green light emitting area 1G is formed to be the smallest, then the light emitting area of the red light emitting area 1R is increased, and the light emitting area of the blue light emitting area 1B is maximized. Is shown.

The order of the sizes of the light emitting areas of the red light emitting region 1R, the green light emitting region 1G, and the blue light emitting region 1B depends on the light emitting efficiency of the light emitting materials. Therefore, the order of the size of the light emitting area is not limited to the above-described G <R <B, but is determined by the light emitting efficiency of the light emitting material used.

FIG. 3 is a cross-sectional view of one display pixel of the organic EL display device taken along line BB of FIG.

One display pixel is composed of an organic EL element 160 that emits any of the assigned R, G, and B, and a first TFT 30 that receives a data signal through a gate signal line 51.
And a storage capacitor SC for holding a data signal supplied from the drain signal line 52 via the first TFT 30, and a current is supplied to the organic EL element 160 via the drive power supply line 53 in accordance with the held drain signal. A second TFT 40 is provided. Among them, the cross section of the first TFT 30 and the storage capacitor SC along the line AA in FIG. 2 is common to that in FIG. Also, in FIG. 3, the second TFT 40 is common to the above-described FIG. 8B.

The organic EL element 160 includes an anode 161 connected to the source 43s of the second TFT 40, a cathode 166 formed as a common electrode on the substrate, and a light emitting element layer 165 having an organic compound disposed between the two electrodes. Are formed. The light-emitting element layer 165 includes at least a light-emitting layer, and may be configured as a single layer or a multi-layer structure.
Consists of

In the present embodiment, a plurality of display pixels R, G, and B arranged in a matrix on the substrate as shown in FIG.
, G, and B organic EL elements 160 use different materials, particularly different materials as organic compounds having a light emitting function.

For example, in the R organic EL element 160R,
As the anode 161, ITO, as the hole transport layer 162,
MTDATA (first hole transport layer) and TPD (second hole transport layer), BeBq ₂ was 2% doped ZnPr as light-emitting layer 163, using the MgIn alloy as the cathode 166.

In the organic EL device for G 160G, ITO is used as the anode 161 and M is used as the hole transport layer 162.
TDATA (first hole transport layer) and TPD (second hole transport layer), BeBq ₂ as the light emitting layer 163, cathode 1
66 is an MgIn alloy.

Further, in the organic EL element 160B for B, ITO is used as the anode 161 and M is used as the hole transport layer 162.
TAZ (first hole transport layer), TPD (second hole transport layer), 1AZM-Hex as the light emitting layer 163,
A MgIn alloy is used as a cathode.

As the organic EL element 160B for B,
Alternatively, a combination of ITO (anode) / MTDATA (first hole transport layer) / TPD (second hole transport layer) / OXD-8 (light emitting layer) / MgIn (cathode) may be used.

The formal names of the compounds described above are as follows.

ZnPr: 5,10,15,20-tetraphenylporphyrinato zinc MTDATA: 4,4,4-tris (3-methylphenylphenyl amino) trip
henylamine TPD: N, N-diphenyl-N, N-di (3-methylphenyl) -1,1-biphe
nyl-4,4-diamine BeBq ₂ : bis (10-hydroxybenzo [h] quinolinato) beryllium 1AZM-Hex: (N, N-disalicylidene-1,6-hexanediaminato)
zinc OXD-8: 3-bis [5- (p-dimethylaminophenyl) -1,3,4-oxadi
azol-2-yl] benzene Further, the organic EL element 160 for R, G, B (160R, 1
When such a material is adopted as 60G, 160B), the luminous efficiency is as follows: element 160G> element 160R> element 16
0B. In the organic EL element 160, the light emission luminance depends on the current (current density). Therefore, in order to make each color have the same luminance when the same current is supplied to each display pixel, as described above, the area of the element light-emitting region is set as region 1G <region 1R <region 1B. Good.

Next, the light emitting area of each display pixel is represented by R,
A method of forming display pixels for appropriately setting different sizes for G and B will be described.

The method is as follows: (i) changing the area of the anode 161 of the organic EL element by R, G, B;
Assuming that the area of the anode 61 is the same, the anode 161 is formed by the flattening insulating film 167 formed after the anode is formed and before the light emitting element layer is formed.
, The contact area between the anode and the light emitting element layer can be changed by R, G, and B.

First, the above-mentioned method (i) for forming display pixels with different anode areas will be described with reference to FIG. FIG. 4 shows a mask for forming the anode 161 of the organic EL element 160 for each of R, G, and B colors.

As shown in FIG. 1, the mask 200A is a mask for setting the area of the light emitting region to 1G <1R <1B, and has openings 201 corresponding to the size of the target anode. In the figure, the largest opening is the opening 201B for the anode for a blue organic EL element having the lowest luminous efficiency among R, G, and B, and the smallest opening is the green organic EL having the highest luminous efficiency. An opening 201G for an element anode. Also, the openings 201B and 201G
The opening having an intermediate size of the opening 201R is an opening 201R for a red EL element anode having lower luminous efficiency than the green EL element and higher than the blue EL element.

Hereinafter, the method (i) will be described in detail with reference to FIG.

A second TFT 40 is formed.
To cover the interlayer insulating film 15 and the drain 4 of the TFT 40.
A driving power supply line 53 connected to 3d and a planarizing insulating film 17 covering the entire surface of the substrate are formed, and a contact hole is formed in a region corresponding to the source 43s of the TFT 40 so as to penetrate the planarizing insulating film 17 and the interlayer insulating film 15. The steps up to the formation of ITO as a transparent electrode (anode) material by sputtering so as to cover the contact holes and the entire surface of the planarizing insulating film 17 are common to the above-described configuration of FIG. 8B.

After the formation of the ITO, a resist is next applied, and exposure and development steps are performed using the mask 200A shown in FIG.
A resist pattern remains only at positions corresponding to R, 201G, and 201B, and ITO is removed by etching with a predetermined etchant using this resist pattern as an etching mask. As a result, an ITO pattern is formed at a size and position corresponding to the openings 201R, 201G, and 201B of the mask 200A.
1 has a different size for each of R, G, and B.

After the anode 161 of the organic EL element is formed in each display pixel area, the R, G, and B light emitting element layers 165 are formed using the above-described organic compound materials different for each of R, G, and B. . In the organic EL element, the material used for the light-emitting element layer has a relatively high resistance, and the light-emitting region is limited to a region between the anode and the cathode in the light-emitting element layer.

Therefore, the light emitting element layer may be the same as the anode forming area or larger than the anode forming area. However, it is necessary that the cathode formed on the light emitting element layer and the anode be short-circuited at the anode end. In order to prevent this, in the present embodiment, as shown in FIG.
Both are set larger than this anode area so as to cover the anode. Needless to say, the light-emitting element layer 165 does not necessarily need to be larger than the anode if other measures are taken to prevent a short circuit between the anode and the cathode. Other treatments include, for example, forming a planarizing insulating film 167 as shown in FIG.

Here, as described above, the organic EL element for R:
ITO // MTDATA / TPD // BeBq ₂ + ZnPr2% // MgIn, Organic EL for B
Element: ITO // MTDATA / TPD // BeBq ₂ // MgIn, organic EL element for G: ITO // MTDATA / TPD // 1AZM-Hex // MgIn or ITO // MTDAT
When the structure of A / TPD // OXD-8 // MgIn is adopted, the same material is used for R, G, and B as the hole transport layer 162 composed of the first and second hole transport layers. When forming the transport layer 162, it is sufficient to form the transport layer 162 on the entire surface on the corresponding anode 161 and the planarization insulating film 17 without distinction of R, G, and B.

In forming the light emitting layer 163,
As described above, in this embodiment, different light-emitting materials are used for R, G, and B, and the materials of the light-emitting layers 163 for each color are changed and formed sequentially. When forming the light emitting layer 163 of each color, the mask 2 as shown in FIG.
Use 00L. The mask 200L is made of a metal such as tungsten (W) or silicon.

As shown in the figure, the mask 200L has openings 202 for forming light emitting layers of the same color on the substrate, and these openings 202 are formed by shifting the position of the mask 200L. Mask 200 shown in FIG.
A is provided so as to overlap with the anode of each color formed using A. At this time, the area of the light-emitting layer may be the same size as the anode, or may be larger than the anode covering the anode. In this embodiment, as shown in FIG. , G, and B are set to be larger than any of the anodes.

For example, when depositing a light emitting layer that emits blue light, the mask 200L is positioned before the evaporation so that the opening 202 of the mask 200L is positioned in the region where the blue light emitting layer is to be formed. It is arranged in close contact with the transport layer 162. After that, an island-shaped blue light-emitting layer corresponding to the opening 202 is formed by depositing a blue light-emitting material.

For vapor deposition of the red light emitting layer, the mask 200L is shifted in the horizontal direction, and the opening 202 of the mask 200L in FIG.
Is used in alignment with the region where the red light emitting layer is to be formed. Similarly, when depositing the green light emitting layer, the opening 202 of the mask 200L is aligned with the region where the green light emitting layer is to be formed and used. According to such a procedure, light-emitting layers having different materials for R, G, and B, but having the same area are sequentially formed on the hole transport layer 162 in an island shape. Thus, the light emitting layer 163 of each color
Can be formed.

After forming the light emitting layer 163, the electron transport layer 164 is formed.
Light emitting layer 163 for the EL element 160 requiring
The electron transport layer 164 is formed by vapor deposition of the electron transport layer 164 on the hole transport layer 162.

A cathode 166 is formed by depositing a magnesium-indium alloy or the like by a sputtering method so as to cover the light emitting element layer 165 obtained by the above method.
Thus, it is possible to obtain a display device using an organic EL element in which the area of the anode is different for each of R, G, and B, and the light emitting area of the element is a desired area for each of R, G, and B.

Next, a method of making the contact area between the anode and the light-emitting layer different with the planarizing insulating film formed between the anode and the light-emitting layer with the same area of the anode (the above (ii)) will be described.

As shown in FIG. 3B, in order to prevent disconnection of the light emitting element layer 165 provided on the anode 161 due to a step of the anode 161, the peripheral edge of the anode 161 is covered with a flattening insulating film 167. It is preferred to cover. In the case of the organic EL element having such a structure, the light emitting region, that is, the light emitting area is substantially the area where the light emitting element layer 165 is in contact with the anode 161, and the anode 161 covered with the planarizing insulating film 167 is provided. Is a region that does not emit light substantially.

Therefore, the anode 1 covered with the planarizing insulating film 167
By making only the area of the periphery of 61 different for each color,
The light emitting area of each color display pixel can be different.

By making the emission areas of the display pixels of each color different, the life of the EL element can be extended.

In this embodiment, when the luminous efficiency is G>R> B, the luminous area of the display pixel is set to G <R <B.
B is described as an example in which the light emission area is different for each color in this order, but the present invention is not limited to this. For example, the luminous efficiency is also G>R> B
In this case, the light emitting area may be set to G ≒ R <B or G <R ≒ B.

Although the flattening insulating film 167 is arranged on the periphery of the anode 161, the invention is not limited to the flattening insulating film, and any other insulating material may be used.

As described above, in the organic EL element which tends to deteriorate faster as the amount of current increases, the EL element luminous layer of the display pixel having low luminous efficiency has a larger current than the luminous layers of other colors. When each color is made to emit light in the same manner by flowing light, it is possible to prevent a problem that the element having low luminous efficiency is selectively deteriorated, and it is possible to prevent the organic EL element of any color from being similarly deteriorated during the same period. As a result, the life of the display device as a whole can be extended.

Examples of the area ratio are as follows.

For example, when the luminance of each of the green, red, and blue light beams to be emitted is 1: 1: 1, if the supply current is constant,
This is the case where the ratio of the luminous efficiency is 10: 3.8: 1.8.
The ratio of the emission area of each color required to achieve the luminance “1” for each color is 1/10: 1 / 3.8: 1 / 1.8 = 1: 1.
2.6: 5.6.

By setting such a light emitting area ratio,
R, G, and B can emit light with the same luminance without passing a large current only to the blue color having the lowest luminous efficiency, so that the life of the light emitting layer can be extended.

Next, another example of the area ratio will be described.
This example is an example in which deterioration of an organic EL element of a color having low luminous efficiency is prevented and control of white balance in full-color display is considered.

When color display is performed by using organic EL elements, which are self-luminous elements, as display pixels, white is displayed by adding the light emitted from each of the R, G, and B organic EL elements.

The white color set as the target is represented by the chromaticity coordinates (x, y) of the NTSC standard white light source (C light source) =
In the case of (0.31, 0.32), the luminance required for R, G, B in order to achieve such white luminance of 100% is R, G, B emitted from each organic EL element. When the chromaticity of each color is represented by coordinates as shown in the upper part of FIG. 6, for example, it is determined as 25%: 46%: 29%. This is represented by a luminance ratio, where R: G: B = 0.54:
1: 0.63.

The ratio of the luminous efficiency of each color of the organic EL element is set to 1 for G, R, and B in the same manner as in the above example.
In the case of 0: 3.8: 1.8, the luminance ratio G, R, B:
The ratio of the emission area required to achieve R: B = 1: 0.54: 0.63 is G: R: B = 1/10: 0.54 /
3.8: 0.63 / 1.8 = 1: 14.2: 35.

As described above, in consideration of the chromaticity of R, G, and B, the chromaticity of the target white, and the luminous efficiency of each color, for example, the area ratio of the luminous region is set to the above value so that the luminous area becomes the above value. By setting the light emitting area for B, it is possible to achieve 100% white luminance when the same amount of current is supplied to the organic EL element of each display pixel.

When the chromaticity of the target white color or the chromaticity of each color changes, the order of the light emission areas of the respective colors determined by the luminance ratio also changes as described above.

As described above, in the EL display device in which the area ratio is determined by such a method, since the luminance balance of each color is adjusted by the light emitting area, the white balance control is very easy and the white balance is very easy. It is not necessary to supply a large amount of current only to the EL element of a specific color in order to display, and the life of the display device as a whole can be improved.

If the materials used are different, the chromaticity coordinate values of the R, G, and B light emitted from the organic EL element are different.
Since the luminance ratio of R, G, and B changes accordingly, and the luminous efficiency also changes, the luminous area ratio is determined accordingly and is not limited to the above numerical values.

In the present invention, when the same current is supplied to the R, G, and B organic EL elements, a white
The invention is not limited to the configuration in which the light emitting area of the element is set so as to achieve 0%. For example, with further consideration of a driver (not shown) that drives each display pixel, it is easy to control the white balance as a whole device, and to prevent a load from being selectively applied to an element having low luminous efficiency. The emission area of each of the R, G, and B organic EL elements may be set.

Further, in the above embodiment, the organic E
Although the present invention has been described with reference to the L display device as an example, the present invention is not limited to this, and an inorganic EL in which a light emitting material is used instead of an organic EL element as a light emitting element is used.
An inorganic EL display device using an element or a fluorescent display tube (VFD: Vacuum) having a fluorescent layer as a light emitting layer between two electrodes
Fluorescent Display) can provide the same effect as the organic EL display device.

The VFD is driven by using a TFT formed on the insulating substrate 10, as in the case of the EL element shown in FIG. In FIG. 3, the steps and structure of the VFD up to the formation of the anode 161 are the same as those of the EL element. However, anode 1
Reference numeral 61 is made of a metal such as Al. A phosphor is deposited thereon, and a grid and a cathode (filament) are arranged above the phosphor. The gap surrounded by the anode and the cathode is in a vacuum state.

The thermoelectrons emitted from the filament are rectified by the grid and collide with the fluorescent material on the anode to emit light. It emits light by itself. A predetermined color can be emitted by selecting a fluorescent substance that emits a predetermined color. The light emitting area may be determined in the same manner as in the case of the above-described EL element. That is, the emission area may be determined according to the emission efficiency of the fluorescent substance.

In the present invention, the light emitting area of the display pixel is the area of the region where the light emitting element of the display pixel actually emits light.

That is, as shown in FIG. 3B, a flattening insulating film provided to prevent the light emitting layer from being disconnected due to a step due to the thickness of the anode and being short-circuited to the cathode. However, when it covers the periphery of the anode, it means the area of a region that emits light substantially when the anode and the light emitting element layer are in direct contact with each other.

In other words, the smaller one of the areas in which the light emitting element layer of the organic EL element is in direct contact with at least one of the anode and the cathode.

In this embodiment, the number of display pixels is 4 rows × 7 columns. However, the present invention is not limited to this, and VGA (640 × 48
0), SVGA (800 × 600), XGA (1024
X768), SXGA (1280 × 1024) and the like can be applied to an arbitrary number of display pixels.

Although the shape of each anode is shown as "L", the present invention is not limited to this. The shape may be rectangular or square, and the shape does not hinder the light emission of the light emitting layer. There is no limitation as long as it has a shape.

Further, in the above-described embodiment, the case where the arrangement of the display pixels of each color is the stripe arrangement has been described. However, the present invention is not limited to this, and the same effect can be obtained even in the delta arrangement and the diagonal arrangement. can get.

Further, in the above-described embodiment, the case of a so-called bottom gate type TFT in which the gate electrode is arranged below the active layer has been described. However, the present invention is not limited to this, and the gate electrode is not limited thereto. The same effect can be obtained even with a so-called top gate type TFT located above the active layer.

[0091]

According to the color display device of the present invention, it is possible to extend the life of the display device having the self-luminous element and obtain a color display device capable of easily controlling the white balance. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view showing a light emitting area of a display pixel of each color of an EL display device of the present invention.

FIG. 2 is a plan view showing the vicinity of a display pixel of the EL display device of the present invention.

FIG. 3 is a cross-sectional view of the EL display device of the present invention.

FIG. 4 is a plan view of a mask for manufacturing an anode of the EL display device of the present invention.

FIG. 5 is a plan view of a mask for manufacturing a light emitting layer of the EL display device of the present invention.

FIG. 6 is an explanatory diagram of a method of obtaining emission luminance ratios of R, G, and B in the case of white display.

FIG. 7 is a plan view showing the vicinity of a display pixel of a conventional EL display device.

FIG. 8 is a sectional view of a conventional EL display device.

FIG. 9 is a plan view showing a light emitting region of a display pixel of each color of a conventional EL display device.

[Explanation of symbols]

 1B Light-emitting area of blue display pixel 1R Light-emitting area of red display pixel 1G Light-emitting area of green display pixel 30 First TFT 40 Second TFT 51 Gate signal line 52 Drain signal line 53 Driving power line 54 Storage capacitance electrode Line 100 EL display 161 Anode 163 Emission layer 165 Emission layer 166 Cathode 200A Anode formation mask 200L Emission layer formation mask 201R Anode formation mask opening 201G Anode formation mask opening 201B Anode formation mask opening Unit 202 Opening of Mask for Forming Light Emitting Layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/14 H05B 33/14 A F term (Reference) 3K007 AB04 AB11 AB17 BA06 CB01 DA01 DB03 EB00 5C080 AA06 BB05 CC03 DD05 EE30 FF11 JJ01 JJ06 5C094 AA08 AA37 AA48 AA56 BA03 BA12 BA27 CA19 CA24 DA13 DB01 DB04 EA04 EA05 EB02 FA01 FB01 FB14 GA10

Claims (10)

[Claims] In a color display device having a self-light-emitting element in a display pixel, a light-emitting area of a display pixel of any one of display pixels of each color is different from a light-emitting area of a display pixel of another color. A color display device characterized by the above-mentioned. 2. The light-emitting area according to claim 1, wherein the light-emitting area is set according to the light-emitting efficiency of the light-emitting element.
2. The color display device according to 1. 3. The light-emitting area includes a luminous efficiency of the self-luminous element provided in the display pixel, a chromaticity of each color emitted by the self-luminous element, and a chromaticity of white of a display device to be set. The color display device according to claim 1, wherein the color display device is set for each color accordingly. 4. The light-emitting area of a self-luminous element having a high luminous efficiency is smaller than the light-emitting area of a self-luminous element having a lower luminous efficiency than a self-luminous element having a high luminous efficiency. 4. The color display device according to 3. 5. The color display device according to claim 2, wherein a light-emitting area of the self-luminous element having the highest luminous efficiency is smaller than a light-emitting area of the self-luminous element having another luminous efficiency. 6. The color display device according to claim 5, wherein the self-luminous element having the highest luminous efficiency is a self-luminous element that emits green light. 7. The color display device according to claim 2, wherein the light-emitting area of the self-luminous element having the lowest luminous efficiency is larger than the light-emitting area of the self-luminous element having the other luminous efficiency. 8. The self-luminous element having the lowest luminous efficiency,
The color display device according to claim 7, wherein the color display device is a self-luminous element that emits red or blue light. 9. The color display device according to claim 2, wherein the luminous area increases in order as the luminous efficiency decreases. 10. The color display device according to claim 1, wherein the self-luminous element is an electroluminescence display device.