JP4899418B2 - LIGHT EMITTING DEVICE AND ELECTRONIC DEVICE - Google Patents

Description

The present invention relates to an organic EL (electroluminescence) type light emitting device employing an optical resonator and an electronic apparatus including the same.

As an organic EL type light emitting device employing an optical resonator, a micro optical resonator is composed of a light emitting layer made of an organic thin film having a light emitting function and reflecting mirrors formed on both sides of the light emitting layer. A multicolor light emitting element having at least two or more pixels having different optical distances between reflecting mirrors of an optical resonator is known (Patent Document 1).

Specifically, a transflective layer, a transparent conductive layer, a light emitting layer made of an organic thin film, and an electrode were sequentially formed on a transparent substrate, and a micro optical resonator was configured between the transflective layer and the electrode. Is. Then, by changing the sum d of the optical distances obtained from the product of the film thickness and the refractive index of each of the transparent conductive layer and the light emitting layer for each pixel, the resonance wavelength is stronger than the emission spectrum component of the original light emitting layer. It is possible to obtain multicolor light emission having different peaks.

Further, in such an optical resonator, when light generated in the organic light emitting layer is reflected at both ends of the resonance part (for example, the transflective layer and the electrode), a phase shift occurs, and this phase shift Φ An equation showing the relationship between radians and resonance wavelength λ is known (Patent Document 2).

Specifically, when the optical distance of the resonance part is L and the peak wavelength of the spectrum of light to be extracted out of the light generated in the organic light emitting layer is λ, the following relational expression is established.
(2L) / λ + Φ / (2π) = m (m is an integer)

Japanese Patent No. 2797883 International Publication No. 01/039554 Pamphlet

However, in a light-emitting device using a multicolor light-emitting element having the above-described optical resonator configuration, when the viewing angle direction changes, the optical distance L substantially changes, and the resonance wavelength peak shifts to the short wavelength side. I know. That is, there is a problem that the hue is shifted depending on the viewing angle direction and the viewing angle range is narrow.

Further, in the actual manufacturing of a light emitting device, since the film thicknesses of the transparent conductive layer and the light emitting layer have variations, the light emission brightness and hue vary in each light emitting element, and a desired light emitting state is obtained. It was necessary to control each film thickness within a limited range. That is, the manufacturing margin is narrow.

The present invention has been made in view of the above problems, and an object thereof is to provide a light emitting device having a wide viewing angle characteristic and a manufacturing margin, and an electronic apparatus including the light emitting device.

The light-emitting device of the present invention includes a light-reflective reflecting layer, a light-transmitting first electrode, a functional layer including at least an organic light-emitting layer, and a light-reflecting element disposed opposite to the first electrode. A light-emitting device including a light-emitting element in which an optical resonator is formed between a reflective layer and a second electrode, the second electrode having the characteristics being sequentially stacked on the substrate and facing the functional layer One of the surface of the reflective layer on the side and the second electrode is made of at least two kinds of materials.

The light reflected from the surfaces of the reflection layer and the second electrode, which are both ends of the optical resonator, undergoes a phase shift. The degree of phase shift varies depending on the material constituting the reflecting surface. According to this configuration,
One surface of the reflective layer on the side facing the functional layer and the second electrode is made of at least two kinds of materials. Therefore, the light from the reflective layer serving as both ends of the optical resonator and the functional layer reflected from the surface of the second electrode is in a state where at least two phase shifts have occurred. Therefore, light extracted from the light-emitting element is synthesized from light having at least two peak wavelengths.
Compared with the light after resonance having one peak wavelength, the emission wavelength range is expanded. Therefore, the shift of the peak wavelength due to the viewing angle can be reduced. In addition, since the shift of the peak wavelength due to the viewing angle is reduced, the optical distance of the optical resonator changes somewhat due to variations in the film thickness of the first electrode and the functional layer that are constituent elements in the manufacturing process for forming the light emitting element. Even so, it is possible to reduce the influence of changes in the brightness and hue of light emission. That is, it is possible to provide a light emitting device having a wide viewing angle characteristic and a manufacturing margin in which a change in brightness and hue of light emission depending on a viewing angle is small.

The light-emitting device of the present invention includes a plurality of light-emitting elements that emit light of different emission colors.
The electrodes may be formed with different film thicknesses corresponding to regions where light of different emission colors is emitted.

According to this configuration, the plurality of light emitting elements have the first electrodes formed with different film thicknesses corresponding to regions where light of different emission colors are emitted, so that the optical distance of the optical resonator is increased. Will be different. Accordingly, each light emitting element has a peak wavelength corresponding to the optical distance of the optical resonator, and can improve the light emission intensity. Therefore, it is possible to provide a light emitting device capable of multicolor light emission having a wide viewing angle characteristic and a manufacturing margin with small changes in light emission brightness and hue depending on the viewing angle.

Further, the plurality of light emitting elements emit red light emission, green light emission, and blue light emission, and at least a reflective layer on a side facing a functional layer of the light emitting element that emits green light emission and a first light emitting element. Either one of the two electrodes may be made of at least two materials. Since green light emission has higher visibility than red light emission and blue light emission, changes in brightness and hue of light emission can be easily recognized. According to this configuration, at least one surface of the reflective layer on the side facing the functional layer of the light emitting element that emits green light emission and the second electrode is made of at least two kinds of materials, Changes in the brightness and hue of light emission depending on the viewing angle can be further reduced. That is, a light emitting device capable of full color light emission having a wide viewing angle characteristic and a manufacturing margin can be provided.

Moreover, it is preferable to have a transparent protective layer between the reflective layer and the first electrode. According to this, since the first electrode is provided on the protective layer covering the reflective layer, the first electrode is formed when compared to the case where the first electrode is formed directly on the reflective layer. Problems such as excessive etching of the reflective layer can be prevented.

The second electrode may have a transflective property that transmits part of light and reflects part of light. According to this, an optical resonator is configured between the reflective layer and the second electrode, and the light emitted from the functional layer is emitted through the second electrode as strong light having a peak wavelength. That is, a top emission type light emitting device having a wide viewing angle characteristic and a manufacturing margin can be provided.

The light emitting device of the present invention further includes a transparent sealing substrate on which different color elements are formed,
The sealing substrate and the substrate may be bonded via an adhesive layer so that different color elements correspond to the plurality of light emitting elements.

According to this configuration, light emitted from the plurality of light emitting elements passes through different color elements and is emitted from the sealing substrate side. Therefore, since the color purity of the light emitted by the color element is stabilized, the change in hue due to the viewing angle can be further reduced. Therefore, a top emission type light emitting device having a wider viewing angle characteristic and a manufacturing margin can be provided.

In the light-emitting device of the present invention, the substrate may be made of a transparent material, and the reflective layer may have transflective properties that transmit part of light and reflect part of light. According to this, the reflective layer and the second
An optical resonator is formed between the electrodes and the light emitted from the functional layer is transmitted through the reflection layer and emitted as strong light having a peak wavelength. That is, a bottom emission type light emitting device having a wide viewing angle characteristic and a manufacturing margin can be provided.

In the light-emitting device of the present invention, it is preferable that at least one of the above-described at least two materials is the same material as the wiring for flowing current to the light-emitting element. And at least 2
At least one of the seed materials may also serve as a wiring for flowing a current to the light emitting element. According to this, it is possible to form a film of at least one of at least two kinds of materials in the step of forming a wiring for passing a current through the light emitting element on the substrate. Therefore, a light emitting element can be formed more efficiently.

In the light emitting device of the present invention, when the surface of the reflective layer facing the functional layer is composed of at least two kinds of materials, at least two kinds of materials are mainly used as Al, Ag, Au,
It is preferable to be selected from Cr, Ta, Mo, Mg, ITO, and IZO. According to this, the reflective layer can be formed using a relatively inexpensive material, and can also be effectively used as a material for wiring for flowing a current to the light emitting element.

In the light-emitting device of the present invention, the surface of the second electrode facing the functional layer is at least 2
When composed of seed materials, at least two kinds of materials are mainly Ca, Li, S
It is preferably selected from r, LiF, and MgF ₂ . According to this, the luminous efficiency can be increased by using a material having a relatively large work function.

An electronic apparatus according to the present invention includes the light emitting device according to the present invention. According to this, since the light emitting device having a wide viewing angle characteristic and a manufacturing margin is mounted, an electronic device having high light emission quality and cost performance can be provided.

In the embodiment of the present invention, an organic EL (electroluminescence) light emitting device as a light emitting device having a functional layer including an organic light emitting layer will be described as an example. In addition, about the structure common to each embodiment, a common code | symbol is used. In addition, the drawings used for the description are appropriately described in order to clarify the configuration.
Enlarging or scaling.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view of a main part showing the organic EL light emitting device of the first embodiment. As shown in FIG. 1, an organic EL light emitting device 10 according to the present embodiment includes an element substrate 1 as a substrate having a plurality of light emitting elements L corresponding to different emission colors, and a seal having different color elements 12r, 12g, and 12b. A stop substrate 2 is provided. In addition, the element substrate 1 and the sealing substrate 2 are bonded via the adhesive layer 11 so that different color elements 12r, 12g, and 12b correspond to the respective light emitting elements L. Color element 12
r is red (Red), color element 12g is green (Green), and color element 12b is blue (B
lue) system.

The light-emitting elements L corresponding to the color elements 12r, 12g, and 12b each have a reflective layer 3 having light reflectivity.
And anodes 5c, 5d, 5f as first electrodes having light transparency, a functional layer K including the organic light emitting layer 7, and light reflectivity disposed so as to face the anodes 5c, 5d, 5f. A cathode 9 as a second electrode is sequentially laminated on the element substrate 1. An optical resonator is configured between the reflective layer 3 and the cathode 9. Organic EL light emitting device 10 provided with such a light emitting element L
Is a so-called top emission type in which the light emission of the light emitting element L is emitted from the sealing substrate 2 side.

The sealing substrate 2 can be a transparent glass substrate or a resin substrate such as plastic. The three different color elements 12r, 12g, and 12b are partitioned by the light shielding portion 13, and are formed, for example, by applying a photosensitive resin containing a pigment as a color element material and exposing and developing it. For example, the light shielding unit 13 has each color element 12r on a shadow mask made of Cr or the like.
, 12g, and 12b are overlapped. These color elements 12r, 12g
, 12b and the light-shielding portion 13, and a planarizing layer 14 is formed to alleviate the unevenness of the surface. For the planarization layer 14, a transparent resin material such as acrylic can be used. A region partitioned by the light shielding unit 13 is a region from which light of different emission colors is emitted.

As the element substrate 1, a transparent glass substrate, an opaque ceramic, a silicon substrate, or the like can be used. The element substrate 1 includes a plurality of TFTs (Thin for driving each light emitting element L).
Film transistor) element (not shown) and a plurality of wirings 1 for supplying current to each light emitting element L
5 and each light emitting element L are formed corresponding to regions where light of different emission colors is emitted. One of the plurality of wirings 15 is connected to the anodes 5c, 5d, and 5f, respectively, and the other is connected to the gate electrodes or source electrodes of the plurality of TFT elements.

The reflective layer 3 is made of two different materials, and is composed of a reflective layer 3a mainly composed of Al and a reflective layer 3b mainly composed of Ag. Each reflective layer 3a, 3b faces the functional layer K side. The main components of the different materials constituting the reflective layer 3 are Al, Ag, Au, Cr,
At least two are selected from Ta, Mo, Mg, ITO, and IZO.

In addition, as a main component of the material constituting the wiring 15, it is desirable to employ one of the different materials constituting the reflective layer 3. In this case, both the wiring 15 and the reflective layer 3a are made of a material mainly composed of Al, and can be formed in the same process and patterned into a desired shape. Furthermore, the wiring 15 and the reflective layer 3 a can be electrically connected, that is, the reflective layer 3 a can also serve as the wiring 15.

The anode 5f of the light emitting element L corresponding to the color element 12r is made of transparent ITO (Indium Tin Oxide).
The film thickness is 30 on the protective layer 4 made of a transparent silicon oxide film covering the reflective layer 3.
nm ITO film 5a, 35 nm ITO film 5b, and 30 nm ITO film 5
c is laminated. As a result, the total film thickness of the anode 5f is 95 nm.

Similarly, the anode 5d of the light emitting element L corresponding to the color element 12g is formed by laminating the ITO film 5b and the ITO film 5c, and the total film thickness is 65 nm. Light emitting element L corresponding to color element 12b
The thickness of the ITO film 5c as the anode is 30 nm. Hereinafter, this is referred to as an anode 5c.
That is, the anodes 5c, 5d, and 5f are formed with different film thicknesses corresponding to regions where light of different emission colors are emitted. Thereby, the optical distance in the optical resonator of each light emitting element L differs, and the light of the different peak wavelength corresponding to the color elements 12r, 12g, 12b of the sealing substrate 2 is emitted.

The functional layer K is formed by sequentially laminating a hole transport layer 6, an organic light emitting layer 7, and an electron transport layer 8 on each of the anodes 5c, 5d, and 5f. Examples of the forming method include a method of applying a material constituting each layer by a spin coating method or a method of vapor deposition in a vacuum.

As materials for forming the hole transport layer 6, the organic light emitting layer 7, and the electron transport layer 8, known materials may be used. In this case, the organic light emitting layer 7 is formed by laminating a plurality of types of organic light emitting materials that emit different emission colors so that single color (white) light emission is possible.

The cathode 9 is formed to cover the functional layer K with a thickness of about 10 nm so that a part of the light emitted from the functional layer K is transmitted and a part of the light is reflected by an evaporation method using a thin film of Mg / Ag. Yes. That is, the cathode 9 is in a half mirror state having transflective properties.

For the adhesive layer 11 that joins the element substrate 1 and the sealing substrate 2, for example, a thermosetting transparent epoxy resin adhesive can be used. It is preferable to use an adhesive that cures at room temperature so that the light-emitting element L formed by lamination does not float due to shrinkage during curing.

Next, the viewing angle characteristics of the organic EL light emitting device 10 will be described with reference to FIGS. Figure 2 shows B
FIG. 3 is a graph showing the emission spectrum of the lue emission region, FIG. 3 is a graph showing the emission spectrum of the Red emission region, and FIGS. 4A to 4C are diagrams showing chromaticity and mathematical expressions representing the chromaticity deviation.
The graphs in FIGS. 2 and 3 show the measured light emission intensity and its wavelength distribution, using a luminance meter capable of spectroscopic measurement, where the light emission intensity inherent in the organic light emitting layer 7 is 1. is there.

As shown in FIG. 2, the emission spectrum of the blue (blue) emission region corresponding to the color element 12b of the sealing substrate 2 is the case of light emitted from the optical resonator between the reflective layer 3a and the cathode 9. , And has a peak wavelength as shown in graph B1 (solid line). Moreover, in the case of the light radiate | emitted from the optical resonator between the reflective layer 3b and the cathode 9, it has a peak wavelength as shown in graph B2 (broken line). That is, since the reflective layer 3a and the reflective layer 3b are made of different materials,
Since the phase shifts of the light reflected by the reflective layers 3a and 3b are different, light having different peak wavelengths is emitted. And actually, light having different peak wavelengths is synthesized and graph B3 (chain line)
A blue light emission having a wide emission wavelength range as shown in FIG.

Further, as shown in FIG. 3, the emission spectrum of the Red (red) emission region corresponding to the color element 12r of the sealing substrate 2 is the light emitted from the optical resonator between the reflective layer 3a and the cathode 9. In this case, it has a peak wavelength as shown in the graph R1 (solid line). The reflective layer 3b and the cathode 9
In the case of the light emitted from the optical resonator between the two, the peak wavelength is as shown in the graph R2 (broken line). That is, since the reflective layer 3a and the reflective layer 3b are made of different materials, the phase shifts of the light reflected by the reflective layers 3a and 3b are different, so that light having different peak wavelengths is emitted. Actually, light having different peak wavelengths is synthesized, and red light emission having a wide light emission wavelength range as shown in the graph R3 (chain line) is obtained. The same applies to the emission spectrum of the green (green) emission region corresponding to the color element 12g.

As shown in FIG. 4, the chromaticity (u ′, v ′) of the light emitted from the light emitting element L is the tristimulus value XY.
It can be obtained from Z (CIE 1931 color system) using the mathematical formulas shown in FIG. Therefore, the chromaticity measured from the front (normal direction with respect to the sealing substrate 2) direction when the organic EL light emitting device 10 emits white light is defined as (u ′ ₁ , v ′ ₁ ), and measured from a direction inclined by 60 degrees. Assuming that the obtained chromaticity is (u ′ _θ , v ′ _θ ), the chromaticity shift Δu′v ′ during this period can be obtained by applying it to the equation in FIG. In the organic EL light emitting device 10 of the present embodiment, Δu′v ′ =
0.05. On the other hand, as a comparative example, the reflective layer 3 in each of the R, G, and B light emitting regions is formed as A
In the case of being composed of one material mainly composed of l, Δu′v ′ = 0.12.

In this way, organic EL that can emit light having a wide emission wavelength range for each of the R, G, and B emission regions.
In the light emitting device 10, the brightness of light emission and the change in hue (chromaticity shift) depending on the viewing angle are reduced, and a wide viewing angle characteristic can be obtained.

The effects of the first embodiment are as follows.
(1) In the organic EL light emitting device 10 according to the first embodiment, the reflective layer 3 facing the functional layer K of the optical resonator is composed of the reflective layer 3a mainly composed of Al and the reflective layer 3b composed mainly of Ag. Since they are made of different materials, the phase shift of the light reflected by the reflective layer 3a and the reflective layer 3b is different.
Accordingly, the light emitted from the optical resonator becomes light having a wide emission wavelength range, and the change in brightness and hue of light emission depending on the viewing angle can be reduced. In addition, since the change in brightness and hue of light emission depending on the viewing angle is small, even if the film thickness of each of the anodes 5c, 5d, 5f and the functional layer K constituting the optical resonator varies somewhat, the effect on the viewing angle characteristics is reduced. be able to. That is, the top emission type organic EL light emitting device 10 having a wide viewing angle characteristic and a manufacturing margin can be provided.

(2) In the organic EL light emitting device 10 of the first embodiment, the reflective layer 3 constituting the optical resonator
For a, the same material as Al as the main component of the wiring 15 for flowing a current to the light emitting element L is used. Therefore, it is possible to simultaneously form the reflective layer 3a in the step of forming the wiring 15. Therefore, since it is not necessary to provide a process for forming the reflective layer 3a again, the manufacturing process can be simplified and the cost can be further reduced.

(3) In the organic EL light emitting device 10 of the first embodiment, the reflective layer 3 made of two different materials is covered with a transparent protective layer 4. Further, anodes 5c and 5d are formed on the protective layer 4.
, 5f are formed. Therefore, when the anodes 5c, 5d, and 5f made of ITO are formed, they can be formed without affecting the film shape of the reflective layer 3 even if the patterning process is repeated. That is, an optical resonator having a stable optical distance can be configured.

(4) In the organic EL light emitting device 10 of the first embodiment, the element substrate 1 having the plurality of light emitting elements L and the sealing substrate 2 having different color elements 12r, 12g, and 12b are bonded via the adhesive layer 11. ing. Therefore, the light emitted from each light emitting element L is the corresponding color element 1.
The light passes through 2r, 12g, and 12b and is emitted from the sealing substrate 2 side. Therefore, the color purity of the emitted light is stable, and the organic EL light emitting device 10 having a wider viewing angle characteristic can be provided.

(Embodiment 2)
FIG. 5 is a schematic cross-sectional view showing a main part of the organic EL light emitting device according to the second embodiment. As shown in FIG. 5, the organic EL light emitting device 20 of the present embodiment has basically the same structure as the organic EL light emitting device 10 of the first embodiment. The material is selected from Al, Ag, Au, Cr, Ta, Mo, Mg, ITO, and IZO as the main component of the material used for each of the reflective layers 3c and 3d. In this case, the reflective layer 3 corresponding to the green (green) light emitting region is composed of two different materials in which the reflective layer 3c has Cr as a main component and the reflective layer 3d has Ta as a main component. The surfaces of these reflective layers 3c and 3d face the functional layer K side to form an optical resonator with the cathode 9. The configuration of the reflective layer 3c in the Red (red) light emitting region and the Blue (blue) light emitting region is a kind of material mainly composed of Cr.

The wiring 15 is mainly composed of Ta, which is the same material as the reflective layer 3d. Therefore,
In the step of forming the wiring 15, the reflective layer 3 d can be formed.

Such an organic EL light emitting device 20 emits green light, and the deviation between the chromaticity measured from the normal direction and the chromaticity measured from the direction inclined by 60 degrees was obtained based on the mathematical formula shown in FIG. The chromaticity shift due to the viewing angle direction was Δu′v ′ = 0.06. On the other hand, as a comparative example, when the reflective layers 3c and 3d in the light emitting regions of R, G, and B are made of one material mainly composed of Al,
Δu′v ′ = 0.15.

In this way, the reflective layer 3 is different in the green light emitting region having the highest visibility.
Even with the use of various materials, the brightness of light emission and the change in hue (chromaticity shift) depending on the viewing angle could be reduced. That is, compared with the organic EL light emitting device 10 of the first embodiment,
A wide viewing angle characteristic can be realized with a simpler configuration.

The effects of the second embodiment have the same effects as the effects (3) and (4) of the first embodiment, and the following effects.

(1) In the organic EL light emitting device 20 of the second embodiment, the reflective layer 3 facing the functional layer K side of the optical resonator in the green light emitting region is mainly composed of the reflective layer 3c and Cr as the main component. Since the reflective layer 3d is made of two different materials, the phase shift of light reflected by the reflective layer 3c and the reflective layer 3d is different. Therefore, the light emitted from the optical resonator in the green light emitting region with the highest visual sensitivity becomes light with a wide light emission wavelength range, and the change in light emission brightness and hue depending on the viewing angle can be reduced. In addition, since the change in brightness and hue of light emission depending on the viewing angle is small, even if the film thicknesses of the anode 5d and the functional layer K constituting the optical resonator vary somewhat, the influence on the viewing angle characteristics can be reduced. That is, the manufacturing margin can be widened. Further, compared with the organic EL light emitting device 10 of the first embodiment, since the reflective layer 3 made of two different materials is provided only in the green light emitting region, a wide viewing angle characteristic and a manufacturing margin can be obtained with a simpler configuration. The organic EL light emitting device 20 having the above can be provided.

(2) In the organic EL light emitting device 20 of the second embodiment, the reflective layer 3 constituting the optical resonator
For d, a material mainly containing Ta, which is the same as the wiring 15 for flowing a current to the light emitting element L, is used. Therefore, it is possible to form the reflective layer 3d at the same time in the step of forming the wiring 15. Therefore, it is not necessary to provide a process for forming the reflective layer 3d again, so that the manufacturing process can be simplified and the cost can be further reduced.

(Embodiment 3)
FIG. 6 is a schematic cross-sectional view of a main part showing the organic EL light emitting device of the third embodiment. As shown in FIG. 6, the organic EL light emitting device 30 of the present embodiment has basically the same structure as the organic EL light emitting device 10 of the first embodiment. And the light emitting element L corresponding to each R, G, B light emission area | region
The reflective layer 3e is made of one material mainly composed of Mo. The surface of the cathode 9 facing the functional layer K is made of two different materials. One is a thin film of Mg · Ag, which is the main material of the cathode 9, and the other is a thin film 9a as a cathode mainly composed of Ca.

Such a light emitting element L includes a reflective layer 3e having light reflectivity on the element substrate 1, a protective layer 4,
The anodes 5c, 5d, and 5f and the functional layer K including the organic light emitting layer 7 are sequentially formed and laminated. Thereafter, Ca is vapor-deposited on the surface of the functional layer K corresponding to approximately half of each light emitting region so as to have a thickness of approximately 5 nm. Then, the cathode 9 is formed by vapor-depositing Mg · Ag to a thickness of about 10 nm.

In the optical resonator between the reflective layer 3e and the cathode 9, there is a phase shift due to reflection of light emitted from the functional layer K between the portion where the thin film 9a mainly composed of Ca is formed and the portion where the thin film 9a is not formed. Different. As a result, there are two different resonance conditions in each of the R, G, and B emission regions, and light having a wider emission wavelength range than that in the case of one resonance condition is emitted. Therefore, the shift of the peak wavelength due to the viewing angle can be reduced, and the manufacturing margin when forming the anodes 5c, 5d, 5f and the functional layer K can be widened.

For the organic EL light emitting device 30 of the present embodiment, the chromaticity deviation was determined by measuring the chromaticity from the direction inclined by 60 degrees with respect to the normal direction in the white light emitting state as in the first embodiment. Δu′v ′ =
0.08. On the other hand, as a comparative example, when the reflective layer 3e in each of the R, G, and B light emitting regions is made of one material mainly composed of Al and the cathode 9 is also made of Mg / Ag, Δ
u′v ′ = 0.12.

In this way, organic EL that can emit light having a wide emission wavelength range for each of the R, G, and B emission regions.
In the light emitting device 30, the brightness of light emission and the change in hue (chromaticity shift) depending on the viewing angle are reduced, and a wide viewing angle characteristic can be obtained.

The material of the thin film 9a can be selected from a metal having a high work function such as Li, Sr, LiF, and MgF ₂ other than Ca, or an alloy thereof. Similarly to the second embodiment, the thin film 9 is formed on the side of the cathode 9 corresponding to the green light emitting region facing the functional layer K.
A wide viewing angle characteristic can be obtained even in a state in which the thin film 9a is not provided in the other red and blue light emitting regions.

The effects of the third embodiment have the same effects as the effects (3) and (4) of the first embodiment, and the following effects.

(1) The organic EL light emitting device 30 of the third embodiment includes the cathode 9 facing the functional layer K of the optical resonator.
Since the thin film 9a containing Ca as a main component is formed on a part of the surface, the phase shift of light reflected by the cathode 9 and the thin film 9a is different. Accordingly, the light emitted from the optical resonator becomes light having a wide emission wavelength range, and the change in brightness and hue of light emission depending on the viewing angle can be reduced. In addition, since the change in brightness and hue of light emission depending on the viewing angle is small, the anode 5 constituting the optical resonator.
Even if the film thicknesses of c, 5d, 5f and the functional layer K vary somewhat, the influence on the viewing angle characteristics can be reduced. That is, the organic EL light emitting device 30 having a wide viewing angle characteristic and a manufacturing margin can be provided.

(Embodiment 4)
FIG. 7 is a schematic cross-sectional view of a main part showing the organic EL light emitting device of the fourth embodiment. As shown in FIG. 7, the organic EL light emitting device 40 of the present embodiment includes an element substrate 41 as a transparent substrate and a plurality of light emitting elements L formed on the surface and emitting monochromatic (red) light emission. I have. Also,
This is a so-called bottom emission type light emitting device in which light emitted from the light emitting element L is emitted to the element substrate 41 side.

The light emitting element L includes a half mirror layer 42 as a reflective layer having transflective properties, an anode 44 as a first electrode having light transmissivity, a functional layer K including an organic light emitting layer 47, and light reflectivity. And a cathode 49 as a second electrode having the above structure are sequentially stacked on the element substrate 41.

As the element substrate 41, a transparent glass substrate or a plastic substrate can be used. On the element substrate 41, a plurality of TFT elements (not shown) for driving each light emitting element L, a plurality of wirings 45 for passing a current to each light emitting element L, and each light emitting element L receive light. It is formed corresponding to the emitted area. One of the wirings 45 is connected to the anode 44, and the other is connected to the gate electrode or source electrode of the TFT element.

The half mirror layer 42 is made of two different materials, and includes a half mirror layer 42a mainly composed of Al and a half mirror layer 42b mainly composed of Ag. Each half mirror layer 42a, 42b faces the functional layer K side. The main components of the different materials constituting the half mirror layer 42 are Al, Ag, Au, Cr, Ta, Mo, Mg, ITO,
Select at least two of the IZO.

Further, it is desirable that one of the different materials constituting the half mirror layer 42 is adopted as the main component of the material constituting the wiring 45. In this case, both the wiring 45 and the half mirror layer 42a are made of a material containing Al as a main component, and can be formed in the same process and patterned into a desired shape. Further, the wiring 45 and the half mirror layer 42 a can be electrically connected, that is, the half mirror layer 42 a can also serve as the wiring 45.

The anode 44 of each light emitting element L is made of transparent ITO, and is formed on the protective layer 43 made of a transparent silicon oxide film covering the half mirror layer 42 so as to have a film thickness of about 50 nm.

The functional layer K is obtained by sequentially stacking a hole transport layer 46, an organic light emitting layer 47, and an electron transport layer 48 on each anode 44. Examples of the forming method include a method of applying a material constituting each layer by a spin coating method or a method of vapor deposition in a vacuum.

As materials for forming the hole transport layer 46, the organic light emitting layer 47, and the electron transport layer 48, known materials may be used. In this case, the organic light emitting layer 47 is formed so as to be capable of emitting monochromatic (red) light. In addition, a plurality of organic light emitting materials capable of emitting different emission colors can be stacked to emit white light.

The cathode 49 is formed to cover the functional layer K with a thickness of about 100 nm so that light emitted from the functional layer K is almost reflected by vapor deposition of Al. That is, an optical resonator is configured between the half mirror layer 42 and the cathode 49.

In such an organic EL light emitting device 40, it is desirable to seal the light emitting element L with a sealing material made of epoxy resin or the like so that the light emitting element L does not deteriorate due to adsorption of moisture or the like.

Since the light emitted from the organic light emitting layer 47 is composed of two different materials for the half mirror layer 42, the phase shift of the reflected light is different between the half mirror layer 42a and the half mirror layer 42b. Therefore, the optical resonator between the half mirror layer 42 and the cathode 49 has two different resonance conditions, and light having a wide emission wavelength range in which light having different peak wavelengths is synthesized is emitted from the light emitting element L. Is done. Therefore, the shift of the peak wavelength due to the viewing angle can be reduced,
Furthermore, it is possible to widen the manufacturing margin when forming the anode 44 and the functional layer K.

For the organic EL light emitting device 40 of the present embodiment, the chromaticity deviation was obtained by measuring the chromaticity from a direction inclined by 60 degrees with respect to the normal direction in a red light emitting state. Δu′v ′ = 0.05. On the other hand, as a comparative example, Δu′v ′ = 0.15 when the half mirror layer 42 is made of one material mainly composed of Al.

Thus, in the organic EL light emitting device 40 capable of obtaining light emission (red) having a wide emission wavelength range, the brightness of light emission and the change in hue (chromaticity shift) depending on the viewing angle are reduced, and a wide viewing angle characteristic can be obtained. became.

The effects of the fourth embodiment are as follows.
(1) In the organic EL light emitting device 40 of the fourth embodiment, the half mirror layer 42 facing the functional layer K of the optical resonator has a half mirror layer 42a mainly composed of Al and a half mirror layer mainly composed of Ag. Since the two different materials 42b are used, the phase shift of the light reflected by the half mirror layer 42a and the half mirror layer 42b is different. Accordingly, the light emitted from the optical resonator becomes light having a wide emission wavelength range, and the change in brightness and hue of light emission depending on the viewing angle can be reduced. In addition, since the change in brightness and hue of light emission depending on the viewing angle is small, even if the film thicknesses of the anode 44 and the functional layer K constituting the optical resonator vary somewhat, the influence on the viewing angle characteristics can be reduced. That is, the bottom emission type organic EL light emitting device 40 having a wide viewing angle characteristic and a manufacturing margin can be provided.

(2) In the organic EL light emitting device 40 of the fourth embodiment, the half mirror layer 42a constituting the optical resonator is made of the same material as the main component of the same wiring 45 as the wiring 45 for flowing current to the light emitting element L. Yes. Therefore, in the step of forming the wiring 45, the half mirror layer 4 is simultaneously formed.
2a can be formed. Therefore, since it is not necessary to provide a process for forming the half mirror layer 42a again, the manufacturing process can be simplified and the cost can be further reduced.

(Embodiment 5)
FIG. 8 is a main part schematic cross-sectional view showing the organic EL light emitting device of the fifth embodiment. As shown in FIG. 8, the organic EL light emitting device 50 of the present embodiment has basically the same structure as the organic EL light emitting device 40 of the fourth embodiment. And the half mirror layer 42a of each light emitting element L is made of Al.
It is comprised from 1 type of material which has as a main component. The surface of the cathode 49 facing the functional layer K is made of two different materials. One is a thin film of Al, which is the main material of the cathode 49, and the other is a thin film 49a as a cathode mainly composed of LiF.

Such a light emitting element L has a half mirror layer 42a having transflective properties on the element substrate 41.
The protective layer 43, the anode 44, and the functional layer K including the organic light emitting layer 47 are sequentially formed and laminated. Thereafter, LiF is vapor-deposited on the surface of the functional layer K corresponding to about half of each light emitting region so as to have a thickness of about 5 nm. Then, the cathode 49 is formed by vapor-depositing Al so as to have a thickness of about 100 nm.

In the optical resonator between the half mirror layer 42a and the cathode 49, the phase shift due to the reflection of the light emitted from the functional layer K between the portion where the thin film 49a mainly composed of LiF is formed and the portion where it is not formed. Is different. As a result, two different resonance conditions exist in the optical resonator of each light emitting region, and light having a wider emission wavelength range than that in the case of one resonance condition is emitted. Therefore, the shift of the peak wavelength due to the viewing angle can be reduced, and the manufacturing margin when forming the anode 44 and the functional layer K can be widened.

For the organic EL light emitting device 50 of the present embodiment, the chromaticity deviation was obtained by measuring the chromaticity from a direction inclined by 60 degrees with respect to the normal direction in a red light emitting state. Δu′v ′ = 0.08. On the other hand, as a comparative example, Δu′v ′ = 0.15 when the half mirror layer 42 is made of one material mainly composed of Al and the cathode 49 is also made of Al.

As described above, in the organic EL light emitting device 50 capable of obtaining light emission (red) having a wide light emission wavelength range, the brightness of light emission and the change in hue (chromaticity shift) depending on the viewing angle are reduced, and a wide viewing angle characteristic can be obtained. became.

The material of the thin film 49a can be selected from a metal having a high work function such as Ca, Li, Sr, MgF ₂ or an alloy thereof other than LiF.

The effect of the fifth embodiment has the same effect as the effect (2) of the fourth embodiment and the following effect.

(1) The organic EL light emitting device 50 according to the fifth embodiment includes the cathode 4 facing the functional layer K of the optical resonator.
Since a thin film 49a containing LiF as a main component is formed on a part of the surface of 9, the phase shift of light reflected by the cathode 49 and the thin film 49a is different. Accordingly, the light emitted from the optical resonator becomes light having a wide emission wavelength range, and the change in brightness and hue of light emission depending on the viewing angle can be reduced. In addition, since the change in brightness and hue of light emission depending on the viewing angle is small, even if the film thicknesses of the anode 44 and the functional layer K constituting the optical resonator vary somewhat, the influence on the viewing angle characteristics can be reduced. That is, the organic EL light emitting device 50 having a wide viewing angle characteristic and a manufacturing margin can be provided.

(Embodiment 6)
Next, regarding an electronic device in which an organic EL light emitting device as a light emitting device of the present invention is mounted, FIG.
And it demonstrates based on FIG. FIG. 9 is a schematic perspective view showing a mobile phone as an electronic apparatus, and FIG. 10 is a schematic cross-sectional view showing an image reading apparatus as an electronic apparatus.

As shown in FIG. 9, the mobile phone 100 as the electronic apparatus of the present embodiment includes numbers, letters,
A main body 101 having an input button 102 capable of inputting symbols and the like, and a display unit 103 attached to the main body 101 in a foldable state are provided. In the display unit 103, a plurality of light emitting elements L capable of emitting different colors are arranged in a matrix.
Any one of the three organic EL light emitting devices 10 to 30 is mounted. Therefore, self-luminous color display is possible.

As shown in FIG. 10, the image reading apparatus 200 as an electronic apparatus according to the present embodiment is a flat bed type image scanner, and is attached so as to close the housing 201 and the opening on the upper surface of the housing 201. An original platen 202 made of transparent glass and a original cover 208 for holding down the original M placed on the original platen 202 are provided. Inside the housing 201 is provided a carriage 203 that can be moved in a direction parallel to the document table 202 by a moving means (not shown). Inside the carriage 203 are a light source 204, a mirror 205, and a condenser lens 2.
06 and a linear image sensor 207 are provided. The light emitted from the light source 204 passes through the document table 202, is reflected by the surface of the document M, is reflected by the mirror 205 again, is collected by the condenser lens 206, and enters the linear image sensor 207. As a result, an image on the surface of the document M can be read. In the light source 204, a plurality of light emitting elements L capable of emitting white light are linearly arranged.
One of 0 is installed.

The effects of the sixth embodiment are as follows.
(1) In the mobile phone 100 of the sixth embodiment, each organic EL light emitting device 10 of the first to third embodiments in which a plurality of light emitting elements L capable of emitting different emission colors are arranged in a matrix on the display unit 103. Any one of? 30 is mounted. Therefore, it is possible to provide the mobile phone 100 having high cost performance capable of confirming an image displayed in a wide viewing angle range with little chromaticity deviation.

(2) In the image reading apparatus 200 according to the sixth embodiment, the light source 204 is mounted with any one of the organic EL light emitting devices 10 to 50 capable of emitting white light having a wide viewing angle characteristic. At the time of attachment, even if the attachment angle varies somewhat, light emission with stable chromaticity is emitted toward the document M. That is, it is possible to provide the image reading apparatus 200 that can attach the light source 204 relatively easily and can read an image with stable quality.

Modifications other than the above embodiment are as follows.
(Modification 1) In each of the organic EL light emitting devices 10 to 50 of the first to fifth embodiments, the arrangement of the reflective layer or the cathode made of different materials is not limited to this. FIG. 11 is a plan view showing an arrangement of different materials. For example, in the light emitting element L of the organic EL light emitting device 10, when the arrangement of the reflective layer 3a and the reflective layer 3b is planarized, different materials A and B are formed so as to divide the light emitting region into two as shown in FIG. Is arranged. Such an arrangement of different materials A and B is shown in FIG.
As shown in 1 (b), the material A may be disposed so as to surround the material B. Further, the types of different materials are not limited to two types, and as shown in FIG. 11C, three different material configurations may be employed in which the material A is disposed so as to surround the materials B and C, respectively.

(Modification 2) In each of the organic EL light emitting devices 10 to 50 of Embodiments 1 to 5, the configuration of the reflective layer or the cathode made of different materials is not limited to this. For example, both the reflective layer and the cathode may be made of at least two kinds of materials, and the surfaces thereof may be disposed so as to face the functional layer K side. According to this, it is possible to obtain a desired peak wavelength by combining various materials.

(Modification 3) In each of the organic EL light emitting devices 10 to 50 of the first to fifth embodiments, the driving method for causing the light emitting element L to emit light is not limited to the active type using the TFT element. The present invention can also be applied to a passive type in which the anode as the first electrode and the cathode as the second electrode are arranged so as to intersect each other in the light emitting region.

(Modification 4) In each of the organic EL light emitting devices 10 to 30 of the first to third embodiments, the element substrate 1 having the light emitting element L and the sealing substrate 2 having the color elements 12r, 12g, and 12b are bonded to the adhesive layer 1.
The structure joined through 1 is not limited to this. For example, the element substrate 1 and the sealing substrate 2 may be bonded and sealed by the adhesive layer 11 arranged in a frame shape under reduced pressure. According to this, the light emitting element L and the color elements 12r, 12g, and 12b are opposed to each other with a gap in a reduced pressure state, and part of the light emission is not absorbed by the adhesive layer 11, so that the organic EL with higher luminance is obtained. Light emitting devices 10 to 30 can be provided.

(Modification 5) In each of the organic EL light emitting devices 10 to 30 of Embodiments 1 to 3, light emission of the functional layer K in the light emitting element L is not limited to white light emission. For example, a partition is provided between each light emitting element L to separate each functional layer K, and the material of each organic light emitting layer 7 is made to have a light emission color corresponding to the color elements 12r, 12g, 12b of the sealing substrate 2. You may change it.

(Modification 6) In each of the organic EL light emitting devices 10 to 30 of Embodiments 1 to 3, the configuration of the sealing substrate 2 is not limited to this. For example, a four-color configuration in which complementary colors are added to the three color elements 12r, 12g, and 12b may be used. Further, the light shielding portion 13 and the planarizing layer 14 are not always necessary. A partition part for partitioning the color elements 12r, 12g, and 12b may be provided, and the color elements 12r, 12g, and 12b may be formed by discharging a functional liquid containing the color element material in the partitioned region.

(Modification 7) In the sixth embodiment, each organic EL light emitting device 10 of the first to fifth embodiments.
˜50 are mounted on the mobile device 100 and the image reading device 200.
It is not limited to. For example, portable information devices called PDA (Personal Digital Assistants), portable terminal devices, word processors, digital still cameras, in-vehicle monitors, digital video cameras, liquid crystal televisions, viewfinder types, monitor direct view type video tape recorders,
It can be suitably used as image display means for car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, video phones, POS terminals, and the like.

1 is a schematic cross-sectional view of a main part showing an organic EL light-emitting device of Embodiment 1. FIG. The graph which shows the emission spectrum of a Blue light emission area | region. The graph which shows the emission spectrum of a Red light emission area | region. (A)-(c) is a figure which shows the numerical formula showing the shift | offset | difference of chromaticity and chromaticity. FIG. 3 is a schematic cross-sectional view of a main part showing an organic EL light emitting device of Embodiment 2. FIG. 6 is a schematic cross-sectional view showing a main part of an organic EL light emitting device according to Embodiment 3. FIG. 6 is a schematic cross-sectional view showing a main part of an organic EL light emitting device according to a fourth embodiment. FIG. 6 is a schematic cross-sectional view showing a main part of an organic EL light emitting device according to a fifth embodiment. FIG. 10 is a schematic perspective view showing a mobile phone as an electronic apparatus according to a sixth embodiment. FIG. 10 is a schematic perspective view illustrating an image reading apparatus as an electronic apparatus according to a sixth embodiment. The top view which shows arrangement | positioning of a different material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 ... Element board | substrate as a board | substrate, 2 ... Sealing board | substrate, 3, 3a, 3b, 3c, 3d, 3e
... reflective layer 4, 43 ... protective layer, 5c, 5d, 5f, 44, ... anode as first electrode, 7
, 47 ... Organic light emitting layer, 9, 49 ... Cathode as second electrode, 9a, 49a ... Thin film as cathode, 10, 20, 30, 40, 50 ... Organic EL light emitting device as light emitting device, 11 ... Adhesion Layer, 12r, 12g, 12b ... color elements, 15, 45 ... wiring, 42, 42a, 42b ... half mirror layer as reflection layer, 100 ... cell phone as electronic device, 200 ... image reading device as electronic device, K: Functional layer, L: Light emitting element.

Claims (13)

A first light-emitting region provided on the substrate to emit a first color; and a second light-emitting region from which a second color is to be emitted.
The first light-emitting region and the second light-emitting region include a reflective layer having light reflectivity, a first electrode having light transmissivity, a functional layer including at least an organic light-emitting layer, and the first is disposed facing the electrode, a second electrode having light reflectivity are sequentially laminated on the substrate, the optical resonator is constituted between the second electrode and the reflective layer,
The surface of the first light emitting region facing the functional layer of the reflective layer or the second electrode includes a first portion and a second portion, and the first portion and the second portion The reflective surfaces of the first part and the second part that reflect light emitted from the organic light emitting layer are mutually different when viewed from a direction perpendicular to the substrate. A light-emitting device that does not overlap . Wherein said first electrode of the first light-emitting area, wherein the first electrode of the second light emitting region, the light emitting device according to claim 1, characterized in that it is formed by different film thicknesses. It said first color is green light emitting light emitting device according to claim 1 or 2, wherein the second color is characterized in that it is a red light emitting or blue-emitting.   The surface of the second light emitting region facing the functional layer of the reflective layer or the second electrode includes a third portion and a fourth portion, and the third portion and the fourth portion The reflective surfaces of the third part and the fourth part that reflect light emitted from the organic light emitting layer are mutually different when viewed from a direction perpendicular to the substrate. The light-emitting device according to claim 1, wherein the light-emitting device does not overlap. The light emitting device according to any one of claims 1 to 4, characterized by having a transparent protective layer between the reflective layer and the first electrode. The light emitting device according to any one of claims 1 to 5, characterized in that it has a semi-transmissive reflective to the second electrode reflects light partially transmits a portion of light. It further comprises a transparent sealing substrate on which different color elements are formed,
Claim 6, wherein the first light-emitting region and the second emission region, wherein said sealing substrate so that different color elements corresponding with said substrate, characterized by comprising bonded via an adhesive layer The light emitting device according to 1. Said substrate is formed of a transparent material, in any one of claims 1 to 5 wherein the reflective layer is characterized by having a semi-transmissive reflective for emitting light part transmits a portion of light The light emitting device described. The first portion and the second portion of the reflective layer of the first light emitting region are composed of different materials,
The light emitting device according to any one of claims 1 to 8 , wherein the first part or the second part is made of the same material as a wiring for flowing a current to the first light emitting region. . The first portion and the second portion of the reflective layer of the first light emitting region are composed of different materials,
The light emitting device according to any one of claims 1 to 8 , wherein the first part or the second part also serves as a wiring for flowing a current to the first light emitting region . The first portion and the second portion of the reflective layer of the first light emitting region are composed of different materials,
The material constituting the first part and the second part is selected from Al, Ag, Au, Cr, Ta, Mo, Mg, ITO, and IZO as a main component. Item 11. The light emitting device according to any one of Items 1 to 10 . The first portion and the second portion of the second electrode of the first light emitting region are made of different materials,
The material constituting the first part and the second part is selected from Al, Ag, Au, Cr, Ta, Mo, Mg, ITO, and IZO as a main component. Item 10. The light emitting device according to any one of Items 1 to 9. An electronic apparatus comprising the light emitting device according to any one of claims 1 to 12 .

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