JP2007122969A - LIGHT EMITTING DEVICE AND ELECTRONIC DEVICE - Google Patents

Abstract

A light-emitting device capable of suppressing a chromaticity shift depending on a viewing angle and an electronic device including the light-emitting element are provided.
In an organic EL device having an optical resonator structure in each blue pixel DB, green pixel DG, and red pixel DR, each blue pixel DB, green pixel DG, and red pixel DR pixel. By forming the electrodes 15B, 15G, and 15R from a first pixel electrode portion and a second pixel electrode portion having a different film thickness from the first pixel electrode portion, each blue pixel DB, green pixel DG, and red Two resonance conditions were provided for the pixel DR.
[Selection] Figure 1

Description

  The present invention relates to a light emitting device and an electronic apparatus.

  2. Description of the Related Art In recent years, development of an organic electroluminescence light emitting device having a pixel including an organic electroluminescence (hereinafter referred to as “organic EL”) element using a light emitting organic material for a light emitting layer has been advanced. In general, an organic EL element has a configuration in which a functional layer including at least a light emitting layer is sandwiched between two electrodes, and light emitted from the light emitting layer is directly used as display light.

However, since the light extracted from the organic EL element as it is has a broad spectrum and low emission luminance, there is a problem that sufficient color reproducibility cannot be obtained when applied to a light emitting device. Therefore, each pixel is provided with a dielectric mirror layer (semi-transparent reflective layer), and the light emitted from the light emitting layer is reflected back and forth between one electrode and the dielectric mirror layer, so that the optical There has been proposed a light-emitting device having a resonator structure in which only light having a resonance wavelength corresponding to the distance is amplified and extracted to the outside. A light-emitting device having such a resonator structure can take out light of wavelengths corresponding to red (R), green (G), and blue (B) by appropriately changing the optical distance. (For example, refer to Patent Document 1).
Japanese Patent No. 2797883

  By the way, in the light emitting device, each electrode and the dielectric mirror are sequentially stacked in the vertical direction with respect to the substrate. Therefore, the optical distance of each pixel is vertical and oblique with respect to the substrate. Apparent optical distance is different.

  As shown in FIGS. 10 (a) and 10 (b), the light having each wavelength corresponding to blue (B) and red (R) emitted obliquely with respect to the substrate has an emission angle Q of 0. It can be seen that the peak wavelength gradually shifts to the short wavelength side as the angle becomes as wide as °, 20 °,. For example, in the light of the wavelength corresponding to blue (B) and red (R), the emission angle Q is 0 °, that is, the light emitted to the front (0 °) with respect to the substrate, and 30 with respect to the substrate. Light with a wavelength shifted by about 10 nm is emitted with light emitted with a shift of °, and light with a wavelength shifted by about 50 nm with light emitted with a shift of 60 ° with respect to the substrate.

  Therefore, the light emitted in the direction perpendicular to the substrate and the light emitted in the oblique direction are different in wavelength, so that a so-called chromaticity shift that looks different depending on the viewing angle (viewing angle) occurs. The problem will arise.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a light emitting device capable of suppressing a chromaticity shift depending on a viewing angle and an electronic device including the light emitting element.

The light-emitting device of the present invention includes a light reflection layer, a first electrode having light transmissivity formed on the light reflection layer, and a light transmission layer disposed opposite to the first electrode. Unit pixel comprising: a second electrode having a light-emitting property and a light-reflecting property; and a functional layer including at least a light-emitting layer disposed between the first electrode and the second electrode. Each of the unit pixels is configured to include two or more resonance conditions.

  According to this, light of two or more different wavelengths is emitted from one unit pixel. Accordingly, the unit pixel is perpendicular to the substrate so that the peak wavelength of light extracted from the unit pixel in an oblique direction with respect to the substrate is equal to the peak wavelength of light extracted from the unit pixel from the direction perpendicular to the substrate. In addition to the resonance wavelength of light observed in the direction, the resonance wavelength observed in an oblique direction with respect to the substrate is set. As a result, the light extracted from the direction perpendicular to the substrate and the light extracted from the oblique direction have the same wavelength, thereby suppressing the occurrence of chromaticity deviation depending on the viewing angle (viewing angle).

  In this light emitting device, each of the unit pixels is a distance between the light reflecting layer and the second electrode, and a first optical distance constituting one resonance condition, and the light reflecting layer. Of the functional layer, the first electrode, and the second electrode so as to have a second optical distance that constitutes another resonance condition between the first electrode and the second electrode. The film thickness of at least any one of them may be adjusted.

  According to this, the wavelength of the light emitted perpendicularly to the substrate is the same as the wavelength of the light emitted obliquely. Therefore, chromaticity deviation does not occur depending on the viewing angle (viewing angle).

In this light emitting device, a protective layer having a refractive index lower than that of the first electrode may be formed between the light reflecting layer and the first electrode.
According to this, the light reflection layer is generally formed of aluminum (Al) or silver (Ag). Therefore, although the light reflection layer is deteriorated by a known developer or stripping solvent used when forming the pixel electrode, a protective layer is formed on the light reflection layer as in the present invention. Therefore, it does not deteriorate. As a result, since the pixel electrode has a high light reflectance, a light-emitting device with high light extraction efficiency, that is, high luminance can be manufactured. The optical resonance wavelength of each pixel is the optical distance between the light reflecting layer and the semi-transmissive reflecting layer, that is, the pixel electrode, the functional layer, and the protective layer disposed between the light reflecting layer and the semi-transmissive reflecting layer. It is known that it corresponds to the sum of the optical distances of the layers, and the optical distance of each layer is obtained by the product of the film thickness and the refractive index. In the present invention, since the refractive index of the protective layer is lower than that of the pixel electrode, the optical resonance wavelength is not affected by the protective layer. When the refractive index of the protective layer is large, it is necessary to form the pixel electrode very thin from the viewpoint of the optical resonator. However, since this can be suppressed, the thickness of the pixel electrode is easy to manufacture. Can be formed.

  In this light-emitting device, the resonance condition is set such that the first optical distance and the second optical distance are set by varying the film thickness of the first electrode for each unit pixel. May be.

  According to this, the optical distance in each unit pixel is set to 2 or more by making the first electrode into, for example, a stepped shape having two or more regions having different film thicknesses. Since the thickness of the light emitting layer is not changed, two or more different resonance conditions can be provided for each unit pixel without changing the light emission characteristics of each unit pixel.

  In this light-emitting device, the functional layer includes at least one of a hole transport layer and an electron transport layer in addition to the light-emitting layer, and the resonance condition includes the hole transport layer and the electron for each unit pixel. The first optical distance and the second optical distance may be set by changing the film thickness of at least one of the transport layers.

According to this, the optical distance in each unit pixel can be set to 2 or more by forming the first electrode into a stepped shape, for example, having two or more regions having different film thicknesses. . Since the thickness of the light emitting layer is not changed, two or more different resonance conditions can be provided for each unit pixel without changing the light emission characteristics of each unit pixel.

  In this light emitting device, the unit pixel includes a red pixel that emits red light, a green pixel that emits green light, and a blue pixel that emits blue light, and the resonance condition is: Of the red pixel, the green pixel, and the blue pixel, only the blue pixel may be set.

  According to this, in a light emitting device capable of full color display that emits red, green, and blue light, the blue pixel that emits blue light is the most among the red pixel, the green pixel, and the blue pixel. Large chromaticity shift due to viewing angle. Therefore, the chromaticity shift due to the viewing angle can be effectively suppressed by setting two or more resonance conditions for the blue pixel.

  In this light emitting device, a color having a red conversion layer at a position facing the red pixel, a green conversion layer at a position facing the green pixel, and a blue conversion layer at a position facing the blue pixel. You may further have a filter.

According to this, since the color filter is provided, a light emitting device with better color reproducibility can be realized.
In the light emitting device, one resonance wavelength constituting the resonance condition may coincide with a wavelength indicating the maximum transmittance in the transmittance characteristic of the color filter.

According to this, it is possible to realize a light-emitting device in which color deviation of red, green, and blue light is suppressed without reducing luminance.
In this light emitting device, one resonance wavelength λ2 constituting the resonance condition is equal to the other resonance wavelength λ1.
(Λ1 + 10 nm) ≦ λ2 ≦ (λ1 + 50 nm)
It may be set to a wavelength range that satisfies the above. According to this, even when the viewing angle is about 60 °, color shift of red, green, and blue light is suppressed. Accordingly, it is possible to realize a light-emitting device that does not cause a chromaticity shift even with a wide viewing angle.

The electronic device of the present invention includes the light emitting device described above.
According to this, it is possible to provide an electronic device capable of displaying an image with suppressed chromaticity deviation even with a wide viewing angle.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of an organic EL device as a light emitting device of the present invention.

The organic EL device 10 of the present embodiment is a so-called top emission type organic EL device that extracts light (display light) emitted from the light emitting layer (internal light emission) from the side opposite to the substrate.
As shown in FIG. 1, the organic EL device 10 includes a light-transmitting substrate (transparent substrate) 11 such as glass, and a blue pixel forming region ZB and a green pixel forming region on the substrate 11. ZG and red pixel formation region ZR are arranged in a matrix. Each of the blue, green, and red pixel formation regions ZB, ZG, and ZR is in the order of the blue pixel formation region ZB → the green pixel formation region ZG → the red pixel formation region ZR →. The pixel formation regions ZB, ZG, and ZR of the same color are arranged along the Z arrow direction (the rear side direction on the paper surface).

  On the substrate 11, a plurality of light reflecting layers 12 made of a material having high light reflectivity and the like are extended in stripes along the same color pixel formation regions ZB, ZG, ZR. The light reflecting layer 12 of this embodiment is made of aluminum (Al).

  A protective layer 13 is formed on each light reflecting layer 12 so as to cover the light reflecting layer 12. The protective layer 13 is made of a material having high light transmittance and electrical insulation. In the present embodiment, the protective layer 13 is made of a material having a lower refractive index than the blue, green, and red pixel electrodes 15B, 15G, and 15R described later. The protective layer 13 is formed, for example, by anodizing the surface of the light reflecting layer 12.

  On the protective layer 13 in each of the blue, green and red pixel formation regions ZB, ZG and ZR, a blue, green and red pixel electrode as a first electrode made of a conductive material having optical transparency. 15B, 15G, and 15R are partitioned. That is, a plurality of blue, green, and red pixel electrodes 15B, 15G, and 15R are arranged in a matrix so as to face each light reflecting layer 12 with the protective layer 13 interposed therebetween. Note that the pixel electrodes 15B, 15G, and 15R of the present embodiment are made of an indium-tin compound (ITO).

  As shown in FIGS. 2 to 4, the blue, green, and red pixel electrodes 15B, 15G, and 15R include the first blue, green, and red pixel electrode portions 18B, 18G, and 18R, and the first blue, The second and fourth pixel electrodes 19B, 19G, and 19R for blue, green, and red have different film thicknesses from the pixel electrodes 18B, 18G, and 18R for green and red.

  As shown in FIG. 2, the film thickness Tb1 of the first blue pixel electrode portion 18B is smaller than the film thickness Tb2 of the second blue pixel electrode portion 19B. Similarly, as shown in FIG. 3, the film thickness Tg1 of the first green pixel electrode portion 18G is smaller than the film thickness Tg2 of the second green pixel electrode portion 19G. Similarly, as shown in FIG. 4, the film thickness Tr1 of the first red pixel electrode portion 18R is smaller than the film thickness Tr2 of the second red pixel electrode portion 19R. That is, each pixel electrode 15B, 15G, 15R has a stepped shape.

  Further, the film thickness Tb1 of the first blue pixel electrode portion 18B is thinner than the film thickness Tg1 of the first green pixel electrode portion 18G, and the film thickness Tg1 of the first green pixel electrode portion 18G is the first red. The pixel electrode portion 18R is thinner than the film thickness Tr1.

  As shown in FIG. 1, a functional layer 20 is formed on the substrate 11 so as to cover the blue, green, and red pixel electrodes 15B, 15G, and 15R. In the functional layer 20 of this embodiment, a hole transport layer 21, a light emitting layer 22, and an electron transport layer 23 are sequentially stacked from the substrate 11 side. A common electrode 25 as a second electrode is formed on the entire surface of the functional layer 20 (on the electron transport layer 23).

The hole transport layer 21 has a function of increasing charge injection efficiency from the blue, green, and red pixel electrodes 15B, 15G, and 15R to the light emitting layer 22, and blocking electrons moving in the light emitting layer 22. There exists an effect | action which raises the recombination probability of the electron and hole in the light emitting layer 22. FIG. For the hole transport layer 21, a material having a low injection barrier from the pixel electrodes 15B, 15G, and 15R and a high hole mobility is preferably used. As such a material, for example, a polythiophene derivative, a polypyrrole derivative, or a doped body thereof is used. Specifically, a dispersion of 3,4-polyethylenedioxyophene / polystyrene sulfonic acid (PEDOT / PSS) [trade name; Bytron-p: manufactured by Bayer Co.], that is, polystyrene sulfone as a dispersion medium. A dispersion obtained by dispersing 3,4-polyethylenedioxythiophene in an acid and further dispersing it in water can be used. In the present embodiment, the hole transport layer 21 has a uniform film thickness for each of the blue, green, and red pixel electrodes 15B, 15G, and 15R.

  The light emitting layer 22 is made of a known polymer light emitting material capable of emitting fluorescence or phosphorescence. Such materials include polyfluorene derivatives (PF), polyparaphenylene vinylene derivatives (PPV), polyphenylene derivatives (PP), polyparaphenylene derivatives (PPP), polyvinylcarbazole (PVK), polythiophene derivatives, polydialkylfluorenes ( PDAF), polyfluorene benzothiadiazole (PFBT), polyalkylthiolene (PAT), polysilanes such as polymethylphenylsilane (PMPS), and the like can be suitably used. In addition, for each of these light emitting materials, polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, quinacridone, etc. It is also possible to use a low molecular weight material doped. In addition, in the light emitting layer 22 of this embodiment, it is comprised with the well-known polymer light emitting material which light-emits white light. In the present embodiment, the light emitting layer 22 has a uniform film thickness over the entire surface of the hole transport layer 21.

  The electron transport layer 23 enhances the electron injection efficiency from the common electrode 25 to the light emitting layer 22 and has a hole blocking function. The electron transport layer 23 is made of an organic material such as an oxadiazole derivative or Alq3. In the present embodiment, the electron transport layer 23 has a uniform film thickness over the entire surface of the light emitting layer 22.

  The common electrode 25 is an electrode that functions as a light transflective film that transmits part of the light emitted from the light emitting layer 22 and reflects part or all of the remaining light to the light reflecting layer 12 side. Therefore, the functional layer 20 is sandwiched between the common electrode 25 and the blue, green, and red pixel electrodes 15B, 15G, and 15R. An optical resonator structure that reflects and resonates light emitted from the light emitting layer 22 so as to reciprocate between the light reflecting layer 12 and the common electrode 25 disposed immediately below the pixel electrodes 15B, 15G, and 15R. Is formed.

  The blue, green, and red pixel formation areas ZB, ZG, and ZR are respectively assigned blue, green, and red pixels DB, DG, and DR as unit pixels. , DG, DR are aligned on the same light reflecting layer 12. That is, among the pixels DB, DG, DR, the blue pixel DB includes the blue pixel electrode 15B (18B, 19B), the common electrode 25, and the blue pixel electrode 15B (18B, 19B) and the common electrode. The organic EL element 28B for blue comprised by the functional layer 20 clamped by 25 is provided. The green pixel DG includes the green pixel electrodes 15G (18G, 19G), the common electrode 25, and the functional layer 20 sandwiched between the green pixel electrodes 15G (18G, 19G) and the common electrode 25, and The organic EL element 28R for green comprised by these is provided. Similarly, the red pixel DR includes the red pixel electrodes 15R (18R, 19R), the common electrode 25, and the functional layer 20 sandwiched between the red pixel electrodes 15R (18R, 19R) and the common electrode 25. The organic EL element 28R for red comprised by these is provided. Note that a plurality of data lines and a plurality of scanning lines (not shown) are formed on the substrate 11, and each pixel DB, DG, DR is formed at a position corresponding to the intersection of each data line and the scanning line. Further, on the substrate 11 corresponding to each pixel DB, DG, DR, driving TFTs such as switching transistors and driving transistors (not shown) for controlling the light emission of the organic EL elements 28B, 28G, 28R are formed.

Next, details of the blue, green, and red pixels DB, DG, and DR will be described.
As shown in FIG. 2, the distance between the light reflection layer 12 and the common electrode 25 corresponding to the vertical direction of the first blue pixel electrode portion 18B (the Y arrow direction in FIG. 2) (this is referred to as “first distance”). The distance between the light reflecting layer 12 and the common electrode 25 corresponding to the vertical direction of the second blue pixel electrode portion 19B (referred to as “second distance”) is denoted by LB2. Then, each hole transport layer 2
1. Since the light emitting layer 22 and the electron transport layer 23 have a uniform film thickness with respect to the pixel electrode 15B, the second distance LB2 is a film thickness Tb1 of the first blue pixel electrode part 18B as compared with the first distance LB1. And a difference (Tb2−Tb1) between the second blue pixel electrode portion 19B and the film thickness Tb2. Similarly, as shown in FIG. 3, the first distance between the light reflecting layer 12 and the common electrode 25 corresponding to the vertical direction (the Y arrow direction in FIG. 3) of the first green pixel electrode portion 18G is LG1. The second distance between the light reflecting layer 12 and the common electrode 25 corresponding to the vertical direction of the second green pixel electrode portion 19G is LG2. Then, the second distance LG2 is different from the first distance LG1 between the film thickness Tg1 of the first green pixel electrode portion 18G and the film thickness Tg2 of the second green pixel electrode portion 19G (Tg2−Tg1). ) Only long.

  Similarly, as shown in FIG. 4, the first distance between the light reflecting layer 12 and the common electrode 25 corresponding to the vertical direction (the Y arrow direction in FIG. 4) of the first red pixel electrode portion 18R is LR1. LR2 is a second distance between the light reflecting layer 12 and the common electrode 25 in the vertical direction of the second red pixel electrode portion 19R. Then, the second distance LR2 is different from the first distance LR1 between the film thickness Tr1 of the first red pixel electrode portion 18R and the film thickness Tr2 of the second red pixel electrode portion 19R (Tr2-Tr1). ) Only long.

  The light emitted from each pixel DB, DG, DR becomes light having a resonance wavelength according to the resonance condition of the optical resonator structure formed in each pixel DB, DG, DR. This resonance wavelength corresponds to the optical distance between the light reflecting layer 12 and the common electrode 25, that is, the sum of the optical distances of the layers disposed between the light reflecting layer 12 and the common electrode 25. The optical distance of each layer is determined by the product of its film thickness and refractive index. In the present embodiment, since the organic EL elements 28B, 28G, and 28R are all made of a common material, the refractive indexes of the respective layers are equal. Therefore, the optical distance of each layer is determined by the first distances LB1, LG1, LR1 and the second distances LB2, LG2, LR2, which are the total thickness of the layers. Note that the resonance wavelength of light increases as the optical distance increases (in the present embodiment, the first distances LB1, LG1, LR1 and the second distances LB2, LG2, LR2 increase). Become.

Therefore, in the present embodiment, as described above, each of the blue, green, and red pixels DB, DG, DR has two types of first distances LB1, LG1, LR1 and second distances LB2, LG2, LR2. Since the distance is provided, the first optical distance corresponding to the first distance LB1, LG1, LR1 and the second optical distance corresponding to the second distance LB2, LG2, LR2 are provided. In other words, each of the blue, green, and red pixels DB, DG, and DR has two different resonance conditions.
(About blue pixel DB)
Both the first and second distances LB1 and LB2 of the blue pixel DB are obtained by resonating light having a wavelength corresponding to blue light, and the first and second blue pixel electrode portions 18B and 19B. Each film thickness Tb1, Tb2 is set. The first distance LB1 is set so that the resonance wavelength PB1 of the blue light HB1 emitted along the direction perpendicular to the substrate 11 (the direction indicated by the arrow Y in FIG. 2) becomes a predetermined desired blue light. It is adjusted by presetting the film thickness Tb1 of the 1-blue pixel electrode portion 18B. In addition, since the second distance LB2 is longer than the first distance LB1, and the optical distance is increased accordingly, blue light HB2 having a longer wavelength than the resonance wavelength PB1 is emitted. The resonance wavelength PB2 of the light HB2 is adjusted by presetting the film thickness Tb2 of the second blue pixel electrode portion 19B so as to satisfy the following expression (1).

(PB1 + 10 nm) ≦ PB2 ≦ (PB1 + 50 nm) (1)
The resonance wavelength PB2 of the light HB2 satisfying the above equation (1) is the resonance of the light emitted in the direction perpendicular to the substrate 11 when the emission angle is emitted in an oblique direction with respect to the substrate 11 at 60 °. The wavelength is substantially equal to the wavelength PB1. That is, the wavelength of the blue light emitted from the blue pixel DB and observed in the vertical direction is substantially equal to the wavelength of the blue light observed in the oblique direction. here,
The emission angle is an angle formed by a parallel direction (X arrow direction in FIG. 1) with respect to a direction perpendicular to the substrate 11 (Y arrow direction in FIG. 1). For example, the exit angle is 0 ° in the direction perpendicular to the substrate 11 (the direction of the arrow Y in FIG. 1), and the exit angle is parallel to the substrate 11 from the perpendicular direction (the direction of the arrow X in FIG. 1). Is 90 °.
(About green pixel DG)
Both the first and second distances LG1 and LG2 of the green pixel DG are obtained by resonating light having a wavelength corresponding to green light. Each film thickness Tg1, Tg2 is set. Specifically, the first distance LG1 is set to a desired green light in which the resonance wavelength PG1 of the green light HG1 emitted along the direction perpendicular to the substrate 11 (the Y arrow direction in FIG. 3) is set in advance. In addition, the thickness Tg1 of the first green pixel electrode portion 18G is adjusted in advance. Further, since the second distance LG2 is longer than the first distance LG1, green light HG2 having a longer wavelength than the resonance wavelength PG1 is emitted. The resonance wavelength PG2 of the light HG2 is expressed by the following formula ( The film thickness Tg2 of the second green pixel electrode portion 19G is adjusted in advance so as to satisfy 2).

(PG1 + 10 nm) ≦ PG2 ≦ (PG1 + 50 nm) (2)
The resonance wavelength PG2 of the light HG2 satisfying the above equation (2) is the resonance of the light emitted in the direction perpendicular to the substrate 11 when the emission angle is emitted in an oblique direction with respect to the substrate 11 at 60 °. It is almost equal to the wavelength PG1. That is, the wavelength of the green light emitted from the green pixel DG and observed in the vertical direction is substantially equal to the wavelength of the green light observed in the oblique direction.
(About red pixel DR)
Both the first and second distances LR1 and LR2 of the red pixel DR are obtained so that light having a wavelength corresponding to red light is obtained by resonance. Each film thickness Tr1, Tr2 is set. Specifically, the first distance LR1 is set to a desired red light in which the resonance wavelength PR1 of the red light HR1 emitted along the direction perpendicular to the substrate 11 (the Y arrow direction in FIG. 4) is set in advance. Further, the film thickness Tr1 of the first red pixel electrode portion 18R is adjusted in advance. Further, since the second distance LR2 is longer than the first distance LR1, the red light HR2 having a longer wavelength than the resonance wavelength PR1 is emitted. The resonance wavelength PR2 of the light HR2 is expressed by the following formula ( The film thickness Tr2 of the second red pixel electrode portion 19R is adjusted in advance so as to satisfy 3).

(PR1 + 10 nm) ≦ PR2 ≦ (PR1 + 50 nm) (3)
The resonance wavelength PR2 of the light HR2 that satisfies the above equation (3) is the resonance of the light emitted in a direction perpendicular to the substrate 11 when the emission angle is emitted in an oblique direction with respect to the substrate 11 at 60 °. It is almost equal to the wavelength PR1. That is, the wavelength of red light emitted from the red pixel DR and observed in the vertical direction is substantially equal to the wavelength of red light observed in the oblique direction.

As described above, the present embodiment has the following effects.
(1) According to the present embodiment, each blue pixel DB, green pixel DG, and red pixel DR each have two resonance conditions. Accordingly, each blue pixel DB emits blue light HB1 having a resonance wavelength PB1 and blue light HB2 having a resonance wavelength PB2 that is longer than the resonance wavelength PB1. Each green pixel DG emits green light HG1 having a resonance wavelength PG1 and green light HG2 having a resonance wavelength PG2 that is longer than the resonance wavelength PG1. Further, red light HR1 having a resonance wavelength PR1 and red light HR2 having a resonance wavelength PR2 that is longer than the resonance wavelength PR1 are emitted from each red pixel DR.

As a result, the light extracted from the oblique direction with respect to the substrate 11 has a shorter wavelength than the light extracted from the vertical direction with respect to the substrate 11, but each resonance wavelength PB2, PG2, PR2 has a long wavelength in advance. Therefore, the substrate 1 is observed by observing the substrate 11 from an oblique direction.
1 is approximately equal to the wavelength of light observed from the direction perpendicular to 1. Therefore, it is possible to display an image that does not cause a so-called chromaticity shift, which looks different in color depending on the viewing angle (viewing angle) with respect to the substrate 11.

  (2) According to this embodiment, each layer of the protective layer 13 and the functional layer 20 has a uniform film thickness for each pixel DB, DG, DR. In addition, each pixel electrode 15B, 15G, 15R is composed of two electrode portions 18B, 18G, 18R and 19B, 19G, 19R having different film thicknesses. Therefore, since the film thickness of the light emitting layer 22 is not changed, two or more different resonance conditions are easily set for each pixel DB, DG, DR without changing the light emission characteristics of each pixel DB, DG, DR. can do.

  (3) According to the present embodiment, the resonance wavelengths PB2, PG2, and PR2 of the light beams HB2, HG2, and HR2 emitted from each blue pixel DB, green pixel DG, and red pixel DR are expressed by the above formula (1 ), (2), and (3). Accordingly, the wavelength of light emitted from each blue pixel DB, green pixel DG, and red pixel DR with respect to the substrate 11 at an emission angle of 60 ° is set to the wavelength of the light emitted in the direction perpendicular to the substrate 11. The resonance wavelengths PB1, PG1, and PR1 can be made substantially equal. As a result, even when the viewing angle is about 60 °, the color shift of red, green, and blue light is suppressed. As a result, it is possible to realize the organic EL device 10 that does not cause a chromaticity shift even with a wide viewing angle.

  (4) According to this embodiment, the protective layer 13 is formed between the light reflection layer 12 and the pixel electrodes 15B, 15G, and 15R so as to cover the entire light reflection layer 12. Accordingly, since the known developer and the solvent of the stripping solution used when forming the pixel electrodes 15B, 15G, and 15R do not come into direct contact with the light reflecting layer 12, the light reflecting layer 12 is not the developer or the stripping solution. There is no deterioration by the solvent. As a result, each of the pixel electrodes 15B, 15G, and 15R has a high light reflectance, so that an organic EL device with high light extraction efficiency, that is, high luminance can be realized.

(5) According to the present embodiment, the protective layer 13 is made of a material having a lower refractive index than the pixel electrodes 15B, 15G, and 15R. Therefore, the resonance wavelengths of the lights HB1, HB2, HG1, HG2, HR1, and HR2 are not affected by the protective layer 13. Therefore, when the refractive index of the protective layer 13 is large, the pixel electrodes 15B, 15G, and 15R need to be formed very thin from the viewpoint of the optical resonator, but this can be suppressed. As a result, the pixel electrodes 15B, 15G, and 15R can be formed with thicknesses that are easy to manufacture.
(Second Embodiment)
Next, an organic EL device according to a second embodiment of the present invention will be described with reference to FIGS.

  The organic EL device 50 of the present embodiment has the same configuration except that the color filter 51 is attached to the organic EL device 10 according to the first embodiment. Therefore, the same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 5, the color filter 51 includes a color filter substrate 52 having light transmittance, and light having a wavelength corresponding to the resonance wavelength of each pixel DB, DG, DR is applied to the color filter substrate 52. Transparent blue, green, and red conversion layers 53B, 53G, and 53R are provided. Each color conversion layer 53B, 53G, 53R is partitioned on the matrix by a black matrix BM.

  In the color filter 51, the blue conversion layer 53B is opposed to the blue pixel DB, the green conversion layer 53G is opposed to the green pixel DG, and the red conversion layer 53R is relative to the red pixel DR. It is attached on the common electrode 25 so as to be arranged at the facing position.

  FIG. 6 is a graph showing the light transmittance with respect to the wavelength of each of the blue, green, and red conversion layers 53B, 53G, and 53R. In FIG. 6, a curve 55B is a curve showing the light transmittance of the blue conversion layer 53B, a curve 55G is a curve showing the light transmittance of the green conversion layer 53G, and a curve 55R is a light transmission of the red conversion layer 53R. It is a curve which shows a rate. In FIG. 6, curves Lb1 and Lb2 are emission spectra of the light HB1 having the resonance wavelength PB1 and the light HB2 having the resonance wavelength PB2, respectively. Similarly, in FIG. 6, curves Lg1 and Lg2 are emission spectra of the light HG1 having the resonance wavelength PG1 and the light HG2 having the resonance wavelength PG2, respectively. Similarly, in FIG. 6, curves Lr1 and Lr2 are emission spectra of the light HR1 having the resonance wavelength PR1 and the light HR2 having the resonance wavelength PR2, respectively.

  As shown in FIG. 6, in the present embodiment, the resonance wavelength PB1 of the light HB1 emitted from each blue pixel DB matches the wavelength indicating the maximum transmittance in the light transmittance characteristics of the blue conversion layer 53B. The first distance LB1 and the second distance LB2 are adjusted as appropriate. Similarly, in the present embodiment, the resonance wavelengths PG1 and PR1 of the lights HG1 and HR1 emitted from the green pixels DG and the red pixels DR correspond to the light transmittance characteristics of the green and red conversion layers 53G and 53R. The first distances LG1, LR1 and the second distances LG2, LR2 are adjusted as appropriate so as to coincide with the wavelength indicating the maximum transmittance.

As described above, the present embodiment has the following effects.
(1) According to the present embodiment, only the light that has passed through the color filter 51 out of the light emitted from the pixels DB, DG, and DR having the optical resonance structure is extracted to the outside. A good organic EL device can be realized.

(2) According to this embodiment, the resonance wavelengths PB1, PG1, and PR1 of the lights HB1, HG1, and HR1 have the maximum transmittance in the light transmittance characteristics of the blue, green, and red conversion layers 53B, 53G, and 53R. It matches the wavelength shown. Therefore, it is possible to realize an organic EL device in which color deviation of red, green, and blue light is suppressed without reducing luminance.
(Third embodiment)
Next, an organic EL device according to a third embodiment of the present invention will be described with reference to FIG.

  The organic EL device 60 of the present embodiment has the same configuration as the organic EL device 10 according to the first embodiment except that the configuration of the pixel electrodes of the green pixel DG and the red pixel DR is different. Therefore, the same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 7, the green pixel electrode 61G in the organic EL device 60 of the present embodiment is configured only from the first green pixel electrode portion 18G having a film thickness Tg1, and the organic EL device according to the first embodiment. No stepped shape as shown in FIG. Similarly, the red pixel electrode 61R in the organic EL device 60 of the present embodiment is configured only from the first red pixel electrode portion 18R having the film thickness Tr1, and the red pixel electrode 61R of the organic EL device 10 according to the first embodiment. It does not have a stepped shape like this. Accordingly, only the green light HG1 having the resonance wavelength PG1 is emitted from the green pixel DG, and only the red light HR1 having the resonance wavelength PR1 is emitted from the red pixel DR.

  Here, it is known that among the blue pixel DB, the green pixel DG, and the red pixel DR, the blue light HB emitted from the blue pixel DB has the largest chromaticity shift due to the viewing angle. Therefore, in the present embodiment, among the blue pixel DB, the green pixel DG, and the red pixel DR, only two blue pixels DB that emit blue light HB having the largest chromaticity shift due to the viewing angle are provided. Resonance conditions are provided.

As described above, the present embodiment has the following effects.
(1) According to the present embodiment, among the blue pixel DB, the green pixel DG, and the red pixel DR, the blue pixel DB that emits the blue light HB having the largest chromaticity shift depending on the viewing angle. Only with two resonance conditions. Therefore, since two resonance conditions are not set for all the pixels DB, DG, and DR, the manufacturing becomes easier as compared with the organic EL device 10 according to the first embodiment. Therefore, it is possible to provide an organic EL device that can be easily manufactured and can suppress a chromaticity shift due to a viewing angle.
(Fourth embodiment)
Next, an organic EL device according to a fourth embodiment of the present invention will be described with reference to FIG.

  In the organic EL device 70 of the present embodiment, the blue pixel electrode 71B is configured only from the first blue pixel electrode portion 18B having a film thickness Tb1, and the green pixel electrode 15G is a first film having a film thickness Tg1. The red pixel electrode 15R is configured only from the green pixel electrode portion 18G, and the red pixel electrode 15R is configured only from the first red pixel electrode portion 18R having the film thickness Tr1. That is, each of the pixel electrodes 15B, 15G, and 15R does not have a stepped shape like the organic EL device 10 according to the first embodiment.

  Further, the hole transport layer 21 constituting the functional layer 20 of each blue pixel DB is not a uniform film thickness with respect to the blue pixel electrode 15B like the organic EL device 10 according to the first embodiment. The film thickness of the hole transport layer 21 on the partial region S (for example, the region where the second blue pixel electrode portion 19B in the organic EL device 10 is formed) is thick. On the hole transport layer 21, a light emitting layer 22 and an electron transport layer 23 are laminated with a uniform thickness. Therefore, the hole transport layer 21 in the blue pixel DB has the same film thickness as the other green and red pixels DG and DR and a film thickness larger than the film thickness of the other green and red pixels DG and DR. have. As a result, the blue pixel DB has two optical distances.

As described above, the present embodiment has the following effects.
(1) According to the present embodiment, the resonance condition is not set by changing the shapes of the blue, green, and red pixel electrodes 15B, 15G, and 15R, but the film thickness of the hole transport layer 21 is appropriately changed. I am trying to set it. As a result, in the same manner as in the third embodiment, among the blue pixel DB, the green pixel DG, and the red pixel DR, the blue pixel DB that emits the blue light HB having the largest chromaticity shift depending on the viewing angle. Only two resonance conditions can be set.
(Fifth embodiment)
Next, an example of an electronic apparatus including the organic EL device according to each of the embodiments will be described.

  FIG. 9 is a perspective view showing an example of a mobile phone. A cellular phone 80 shown in FIG. 9 includes a plurality of operation buttons 81, a mouthpiece 82, a mouthpiece 83, and a display unit 84. The mobile phone 80 having such a characteristic has the display unit 84 provided with any one of the organic EL devices 10, 50, 60, and 70 according to the first to fourth embodiments. Therefore, an image that does not cause a chromaticity shift is displayed on the display unit 84 of the mobile phone 80 even when the viewing angle is wide.

In addition, this invention can also be changed and embodied as follows.
In the fourth embodiment, the resonance condition of the blue pixel electrode 15B is set to two by changing the film thickness of a part of the hole transport layer 21 on the blue pixel electrode 15B. It is not limited to this. For example, the resonance condition of the blue pixel electrode 15B may be set to two by changing the film thickness of a part of the electron transport layer 23. Alternatively, the resonance condition of the blue pixel electrode 15B may be set to two by changing a part of the thickness of the light emitting layer 22. Furthermore, the resonance condition of the blue pixel electrode 15B may be set to two by changing a part of the thickness of the protective layer 13 or changing a part of the thickness of the light reflecting layer 12 itself. In short, it is only necessary to change the optical distance by changing the film thickness of each layer of the blue pixel electrode 15B.

In each embodiment described above, the functional layer 20 includes the hole transport layer 21, the light emitting layer 22, and the electron transport layer 23.
However, the present invention is not limited to this. Any one or all of the above layers 21 to 23 other than the light emitting layer 22 (a hole injection layer or an electron injection layer) may be included. In short, the functional layer 20 only needs to include the light emitting layer 22. By doing in this way, the same effect as each above-mentioned embodiment can be acquired.

  In the above embodiments, the resonance wavelengths PB2, PG2, and PR2 of the light beams HB2, HG2, and HR2 emitted from the blue pixel DB, the green pixel DG, and the red pixel DR are expressed by the above equations (1), ( Although determined to satisfy 2) and (3), the present invention is not limited to this. In short, each of the blue pixel DB, the green pixel DG, and the red pixel DR may emit light of two types of resonance wavelengths.

  In each of the above embodiments, the optical distance between each blue pixel DB, green pixel DG, and red pixel DR is equal to each layer 21, 22 constituting each blue pixel DB, green pixel DG, and red pixel DR. , 23 are made of the same common material, the refractive indexes of the respective layers 21, 22, 23 are made the same, and the film thicknesses are changed as appropriate so as to be set appropriately. The film thickness of each layer 21, 22, and 23 is made uniform in each blue pixel DB, green pixel DG, and red pixel DR, and each blue pixel DB, green pixel DG, and red pixel DR is divided into pixels. The optical distance may be appropriately set by adjusting the refractive index by changing the materials of the electrodes 15B, 15G, and 15R and the materials of the layers 21, 22, and 23. By doing in this way, since the surface of the functional layer 20 can be made flat, the adhesiveness of the functional layer 20 and the common electrode 25 improves. As a result, since the electrical connection between the functional layer 20 and the common electrode 25 is improved, the yield of the organic EL devices 10, 50, 60, and 70 having an optical resonance structure can be improved.

  In each of the above embodiments, the light emitting layer 22 is applied to the organic EL devices 10, 50, 60, and 70 using a light emitting organic material. The present invention is applicable even to a light emitting device using a light emitting diode (LED) element.

  In the fifth embodiment, the mobile phone 80 has been described as an electronic device. However, the present invention is not limited to this, and can be widely applied to electronic devices including a display such as a mobile personal computer or a digital camera. .

  In each of the above embodiments, the substrate 11 is a substrate (transparent substrate) having light transmissivity such as glass, but the present invention is not limited to this. For example, a substrate that does not transmit light (an opaque substrate) can also be used. When the substrate 11 is a substrate that does not transmit light (opaque substrate), for example, a ceramic sheet such as alumina, a metal sheet such as stainless steel that has been subjected to an insulation treatment such as surface oxidation, or thermosetting Examples thereof include a resin, a thermoplastic resin, and a film (plastic film). In short, any pixel can be used as long as the pixel can be formed.

  In each of the above embodiments, the light reflecting layer 12 is made of aluminum (Al), but is not limited thereto, and may be made of any material as long as it has excellent light reflectivity. For example, you may be comprised with silver (Ag).

  In each of the above embodiments, the unit pixels are embodied as blue, green, and red pixels DB, DG, and DR. However, this is embodied in pixels other than the blue, green, and red pixels DB, DG, and DR. Also good. For example, the present invention may be embodied in pixels of colors that emit light of colors other than blue, green, and red.

In each of the above embodiments, the first electrode is the pixel electrode 15B, 15G, 15R, the second electrode is the common electrode 25, and the light emitted from the light emitting layer 22 is extracted from the side opposite to the substrate 11.
Although the embodiment is embodied in a so-called top emission type organic EL device 10, the present invention is not limited to this. The light emission from the light emitting layer 22 may be embodied in a so-called bottom emission type organic EL device 10 that extracts light from the substrate 11 side.

1 is a cross-sectional view of an organic EL display according to a first embodiment. FIG. The expanded sectional view of the pixel for blue. The expanded sectional view of the pixel for green. The expanded sectional view of the pixel for red. FIG. 6 is a cross-sectional view of an organic EL display according to a second embodiment. The graph which shows the light transmittance of a color filter. FIG. 6 is a cross-sectional view of an organic EL display according to a third embodiment. The sectional view of the organic EL display concerning a 4th embodiment. The perspective view of the mobile telephone as an electronic device. (A) is the emission intensity of blue light emitted at various emission angles, and (b) is the emission intensity of red light emitted at various emission angles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... Light reflection layer, 15B ... Blue pixel electrode as 1st electrode, 15G ... Green pixel electrode as 1st electrode, 15R ... Red pixel electrode as 1st electrode, 25 ... Common electrode as second electrode, 22 ... Light emitting layer, 20 ... Functional layer, DB ... Blue pixel as unit pixel, DG ... Green pixel as unit pixel, DR ... Red pixel as unit pixel, PB2 ... resonance wavelength of blue pixel light as one resonance wavelength (λ1), PG2 ... resonance wavelength of green pixel light as one resonance wavelength (λ1), PR2 ... resonance wavelength (λ1) as one resonance wavelength (λ1) The resonance wavelength of the red pixel light, PB1... The resonance wavelength of the blue pixel light as the other resonance wavelength (λ2), PG1... The resonance wavelength of the green pixel light as the other resonance wavelength (λ2), PR1... The red pixel light as the other resonance wavelength (λ2) Wavelength 10, 50, 60, 70 ... Organic EL device as light emitting device, 21 ... hole transport layer, 23 ... electron transport layer, 51 ... color filter, 53B ... blue conversion layer, 53G ... green conversion layer, 53R ... Red conversion layer 80: A mobile phone as an electronic device.

Claims (10)

A light reflecting layer formed on the substrate, a light transmissive first electrode formed on the light reflecting layer, and light transmissive and light reflective disposed to face the first electrode. A light-emitting device including a plurality of unit pixels each including a second electrode and a functional layer that is disposed between the first electrode and the second electrode and includes at least a light-emitting layer. There,
Each of the unit pixels is configured to include two or more resonance conditions. The light-emitting device according to claim 1.
Each of the unit pixels is a distance between the light reflection layer and the second electrode, and includes a first optical distance constituting one resonance condition, the light reflection layer, and the second electrode. At least one of the functional layer, the first electrode, and the second electrode so as to have a distance between the electrodes and a second optical distance constituting another resonance condition A light emitting device in which one film thickness is adjusted. The light emitting device according to claim 1 or 2,
A light-emitting device, wherein a protective layer having a refractive index lower than that of the first electrode is formed between the light reflecting layer and the first electrode. The light-emitting device according to claim 2 or 3,
The resonance condition is such that the first optical distance and the second optical distance are set by making the film thickness of the first electrode different for each unit pixel. Light-emitting device. In the light-emitting device of any one of Claims 2-4,
The functional layer includes at least one of a hole transport layer and an electron transport layer in addition to the light emitting layer,
The resonance condition may be that the first optical distance and the second optical distance are changed by changing a film thickness of at least one of the hole transport layer and the electron transport layer for each unit pixel. A light emitting device characterized in that a distance is set. In the light-emitting device of any one of Claims 1-5,
The unit pixel includes a red pixel that emits red light, a green pixel that emits green light, and a blue pixel that emits blue light.
The light emitting device according to claim 1, wherein the resonance condition is set only for the blue pixel among the red pixel, the green pixel, and the blue pixel. The light-emitting device according to claim 6.
The color filter further includes a red color conversion layer at a position opposite to the red pixel, a green color conversion layer at a position opposite to the green pixel, and a blue color conversion layer at a position opposite to the blue pixel. A light emitting device characterized by the above. The light-emitting device according to claim 7.
The light emitting device according to claim 1, wherein one resonance wavelength constituting the resonance condition coincides with a wavelength indicating a maximum transmittance in a transmittance characteristic of the color filter. The light-emitting device according to claim 8.
One resonance wavelength λ2 constituting the resonance condition is relative to the other resonance wavelength λ1.
(Λ1 + 10 nm) ≦ λ2 ≦ (λ1 + 50 nm)
The light emitting device is set to a wavelength range satisfying the above. An electronic apparatus comprising the light emitting device according to claim 1.

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