JP2002151251A - Luminous element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous element which can effectively utilize light emitted, even in case of one with an anti-outside-light-reflection function. SOLUTION: A luminous layer 14 emits circularly polarized light asymmetrically, with intensity ratio of left circular polarization light 30 to right circular polarization light 32 at, say, 0.2:0.8. A phase difference plate 18 of λ/4 plate is arranged so that the angle between its delayed-phase axis and transmission axis of a linear polarizing plate 20 be, say, +45 deg.. Therefore, left circular polarization component of 20% is absorbed by the linear polarizing plate since it becomes linear polarization light vertical to the transmission axis of the linear polarizing plate 20 by passing through the wave plate 18, but right circular polarization light of 80% passed through the linear polarizing plate 20 and emits light since it becomes linear polarization light parallel to the transmission axis of the linear polarizing plate 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a light emitting device.

[0002]

2. Description of the Related Art Inorganic EL displays and organic EL displays have been actively studied as alternative thin displays because they can easily solve the drawbacks of liquid crystal displays, such as low contrast and narrow viewing angle. ing.

FIG. 15 shows a typical structure of an organic EL display. Usually, an ITO electrode is used for the anode 100, and a light-reflective aluminum electrode or the like is used for the cathode 102. Light emitted from the light emitting layer 104 in the ITO direction passes through the glass substrate 106 as it is, and light emitted toward the aluminum electrode 102 is once reflected by the aluminum electrode 102 and
6 is transmitted. As described above, when a light-reflective electrode is used, light emitted on one electrode side can be used, so that efficiency is high.

However, in the case of this structure, if the ambient light is used in a bright place, the external light is reflected by the cathode 102, so that the luminance in a state where no light is emitted, that is, a black state becomes high, and the contrast is remarkably lowered. There was a disadvantage. Therefore, how to suppress the reflection of external light has been an important issue.

As means for solving this problem, Japanese Patent Laid-Open No.
321381 proposes a method for suppressing the reflection of external light by using a circularly polarizing plate 114 composed of a linearly polarizing plate 110 and a phase difference plate 112 as shown in FIG. This method is described below. In FIG. 16, the same reference numerals as those in FIG. 15 indicate the same components.

In FIG. 16, the slow axis of the phase difference plate 112 is inclined at +45 degrees or +135 degrees from the transmission axis of the linear polarizing plate 110. The circularly polarizing plate 1 on which each element is arranged as described above
14 produces right-handed or left-handed circularly polarized light. When circularly polarized light is reflected, the direction of the circularly polarized light changes. Therefore, the right circularly polarized light becomes left circularly polarized light by reflection, and the left circularly polarized light becomes right circularly polarized light by reflection. Therefore, light incident from the outside and passing through the circularly polarizing plate 114 becomes right or left circularly polarized light, is reflected by the cathode 116 which is a metal electrode on the back surface, and travels toward the outside of the element. At that time, since the reflected light is circularly polarized in the opposite direction to the incident light, it passes through the retardation plate again, and becomes linearly polarized light that oscillates in a direction perpendicular to the transmission axis direction of the linearly polarizing plate. Is absorbed by the linear polarizing plate, and as a result, reflection of external light is suppressed.

In Japanese Patent Application Laid-Open No. 9-127885, a λ / 4 plate using a single-layer birefringent plate can only suppress the reflection of external light in a narrow wavelength range. As shown in FIG. 17, a linear polarizing plate 120 and a plurality of birefringent plates, for example, two birefringent plates 122 and 124 are combined so as to obtain a broadband λ / 4 phase difference as shown in FIG. A method using the wideband λ / 4 plate 126 has been proposed. In FIG. 17, the same reference numerals as those in FIG. 15 indicate the same components.

By the way, in the method for suppressing the reflection of external light as described above, light emission is non-polarized light emission. Recently, organic EL materials that emit polarized light have been studied.
Luo, the intensity of the right circularly polarized light intensity of left circular polarization and I _R and I _L,

[0009]

(Equation 2)

When g is defined as 0, a material that emits circularly polarized light has been developed. (J. Am. Chem. Soc., Vol. 1
19, No. 41, 1997, 9909-9910).

[0011]

In the method using a circularly polarizing plate disclosed in Japanese Patent Application Laid-Open No. 8-321381, the emitted light is unpolarized and is absorbed by the circularly polarizing plate by about 50%. The luminous efficiency is about half that of the case where no circularly polarizing plate is used.

For the same reason, the method using a linear polarizer and a broadband circular polarizer composed of a plurality of birefringent plates disclosed in Japanese Patent Application Laid-Open No. Hei 9-127885 also provides a circular polarizer having a broad output intensity and luminous efficiency for the same reason. It is about half of the case without a board.

As described above, in the element having the external light reflection preventing function in which the linear polarizing plate and the phase difference plate are combined, the intensity of light emitted to the outside and the intensity of the light emitted to the outside are higher than those of the element having no external light reflection preventing function. The luminous efficiency is reduced by about half.

In view of the above, it is an object of the present invention to provide a light emitting element which can effectively use emitted light even in an element having an external light reflection preventing function.

[0015]

In order to solve the above-mentioned problems, a light-emitting device according to the present invention comprises a light-emitting layer that emits circularly polarized light having different left and right circularly polarized light intensities, and a circularly polarizing plate. I do.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as a preferred embodiment of the present invention, a light emitting layer that emits light of g ≠ 0 and a circularly polarizing plate combining a single retardation plate and a linearly polarizing plate are described. The light-emitting element included will be described below based on the cross-sectional view of the element illustrated in FIG.

On one side of the glass substrate 10, an anode 12,
A light-emitting layer 14 and a light-reflective cathode 16 are formed. In this embodiment, a glass substrate is used as the substrate. However, any material may be used as long as it is a light-transmitting material. For example, a plastic substrate or the like may be used. Although ITO is usually used for the anode 12, it is not necessary to limit to this. Light emitting layer 14
Has characteristics of emitting circularly polarized light and having different left and right circularly polarized light intensities. That is, in the light emitting layer 14, the intensity of the right circularly polarized light is I _R , and the intensity of the left circularly polarized light is I _L ,

[0018]

(Equation 3)

In the definition, a material that emits circularly polarized light with g ≠ 0 is used. Although only a single layer of the light-emitting layer 14 is illustrated in this figure, a hole injection layer or another layer may be formed between the anode 12 and the light-emitting layer 14, or between the anode 16 and the light-emitting layer 14. An electron injection layer or another layer may be formed on the substrate. A light reflective electrode is formed on the cathode 16, and aluminum or the like is usually used. On the other surface of the glass substrate 10, a retardation plate 18 and a linear polarizing plate 20 are arranged. Note that these may be arranged between the substrate 10 and the anode 12. The phase difference plate 18 is a λ / 4 plate, and a phase difference plate having a phase difference of 135 nm is usually used so as to satisfy the λ / 4 plate condition for light having a wavelength of 550 nm. However, it is not limited to this. Although FIG. 1 shows a single retardation plate, a wide band λ /
If four plates are used, a plurality of retardation plates may be used. The phase difference plate 18 of the λ / 4 plate and the linear polarizer 20 form a circular polarizer 22.

Next, FIG. 2 shows an optical geometry when g <0, and FIG. 3 shows an optical geometry when g> 0. 2 and 3, the same reference numerals as those in FIG. 1 indicate the same components. When facing the light emitting surface, when the leftward direction is +, the angle between the slow axis of the phase difference plate 18 and the transmission axis of the linear polarizer 20 is θ.

FIG. 4 shows the result of calculating the external light reflectance (%) when g is changed from 30 ° to 60 ° in consideration of the actual state such as the transmittance when g <0. From FIG. 4 +
This angle is the most preferable because the reflection of external light can be prevented most when the angle is 45 °, and when the external light reflectance is suppressed to 5% or less, θ may be in the range of + 40 ° ≦ θ ≦ + 50 °. It turns out that it is necessary.

On the other hand, θ = + 45 ° at g <0 is g>
Since g corresponds to θ = + 135 ° at 0, g> 0
In this case, the external light reflectance also becomes the lowest at + 135 °, which is the same as the characteristic shown in FIG. Therefore, since the reflection of external light can be prevented most when the angle is + 135 °, this angle is the most preferable. When the external light reflectance is suppressed to 5% or less, θ is +130.
It is necessary to be within the range of ° ≦ θ ≦ + 140 °.

In the two geometries shown in FIGS. 2 and 3, when θ is at +45 degrees and +135 degrees, respectively, the external light reflection spectrum is as shown in FIG. 5, the reflection of external light is suppressed, and a good contrast is obtained. Obtainable.

In the above structure, the emitted light is emitted from the substrate side. A structure in which a light-reflective cathode, a light-emitting layer, an anode, a retardation plate, and a polarizing plate are sequentially laminated on a substrate may be used.
In this case, the emitted light is emitted in a direction opposite to the direction of the substrate.

Next, FIG. 6 shows the reason why the emitted light can be extracted more efficiently by using the light emitting element as described above than when the light emitting layer which emits non-polarized light is used. Based on FIG. 7, the case where g> 0 will be described. 6 and 7, the same reference numerals as those in FIG. 1 indicate the same components.

First, the case where g <0 will be described with reference to FIG. Assuming that the intensity of light emitted from the light emitting layer 14 and traveling in the light emission direction is I, the intensity ratio between the left circularly polarized light 30 and the right circularly polarized light 32 is, for example, I _L = 0.2I, I _R = 0.
8I. A phase difference plate 18 is lambda / 4 plate, when the slow axis angle of the transmission axis of the linear polarizer 20 + 45 ° phase difference plate 18, the left circularly polarized light component I _L is the phase difference plate 18 By passing through, the light becomes linearly polarized light perpendicular to the transmission axis of the linearly polarizing plate 20, and is absorbed by the linearly polarizing plate 20. On the other hand, I _R is the right circularly polarized light component passes through the phase plate 18, since the transmission axis of the linear polarizer 20 and the linearly polarized light parallel, the light absorption of the transmission axis of the linear polarizer 20 Assuming that there is no light, light having an intensity of 0.8I passes through the linear polarizer 20 and exits.

Next, the case where g> 0 will be described with reference to FIG. As an example of g> 0, it is assumed that the intensity ratio between the left circularly polarized light 30 and the right circularly polarized light 32 is I _L = 0.8I and I _R = 0.2I. Assuming that the angle between the slow axis of the phase difference plate 18 and the transmission axis of the linear polarizing plate 20 is + 135 °, the right circularly polarized light component I
_R passes through the retardation plate 18 and becomes linearly polarized light perpendicular to the transmission axis of the linearly polarizing plate 20, and is absorbed by the linearly polarizing plate 20. On the other hand, the left circularly polarized component I
_L passes through the phase difference plate 18 to form the polarizing plate 18.
Becomes linearly polarized light parallel to the transmission axis of
Assuming that there is no light absorption in the transmission axis direction of
The light I passes through the linear polarizer 20 and exits.

On the other hand, when the light emitting layer emits non-polarized light as in the prior art, the intensity I of the light traveling in the light emitting direction is 50% absorbed by the polarizing plate.
Only the light of 5I is emitted.

According to the above principle, the use of the light emitting device of the present invention makes it possible to effectively use emitted light. Therefore, in the light emitting element of the present invention, it is possible to reliably suppress the reflection of external light and to emit emitted light to the outside more efficiently than in the case where a light emitting layer that emits non-polarized light is used.

Next, a description will be given of a light emitting device according to a second embodiment of the present invention in which two phase difference plates 18a and 18b are used as phase difference plates as shown in FIG. 8, the same reference numerals as those in FIG. 1 denote the same components, and a description thereof will not be repeated. In FIG. 8, the first retardation plate 18a is a λ / 4 plate, and the second retardation plate 18b is a λ / 2 plate. The first and second retardation plates 18a and 18b and the linear polarizer 20 form a circular polarizer 22. Since the basic structure is the same as the case where one retardation plate shown in FIG. 1 is used, here, the optical geometry is described.
The case of> 0 will be described with reference to FIG. 9 and 1
At 0, the same reference numerals as in FIG. 8 indicate the same components.

[0031] when facing the light emitting surface, and the left-handed direction + a, the angle of the transmission axis of the slow axis and linear polarizer 20 of the first retardation plate 18a and theta _1, the second phase difference when the angle of the transmission axis of the slow axis and linear polarizer 20 of the plate 18b and the theta _2, orthogonal to the transmission axis of the linear polarizer 20 external light incident to the light emitting element is reflected by the cathode 16 When the relationship that θ ₁ and θ ₂ satisfy to obtain linear deflection is obtained by the Poincare sphere, the following is obtained.

[0032]

_{1 1} = 2θ ₂ + 45 ° Under this relationship, when g <0, the external light reflectance (%) when θ ₂ is changed from 0 ° to 30 ° is the actual transmittance or the like. FIG. 11 shows the result calculated in consideration of the state. From FIG. 11, when θ ₂ is + 15 °, the reflection of external light can be prevented most. Therefore, this angle is most preferable. When the external light reflectance is suppressed to 0.1% or less, θ ₂ is + 10 ° ≦ θ _2. It is understood that it is necessary to be within the range of ≦ + 20 °.

On the other hand, when g <0, θ ₂ = + 15 ° is g
G> 0 because it corresponds to θ = + 75 ° at> 0
In this case, the external light reflectance also becomes the lowest at + 75 °, and has the same characteristics as in FIG. Accordingly, the angle of + 75 ° is the most preferable since the reflection of external light can be prevented most when + 75 °, and + 70 ° ≦ θ when the external light reflectance is suppressed to 0.1% or less.
It must be in the range of ₂ ≦ + 80 °.

The effect of using two phase difference plates is that, as shown in the reflection spectrum of FIG. 12, external light reflection can be prevented over a wider band than when a single phase difference plate is used. This is because a combination of a linear polarizing plate and two retardation plates results in a circular polarizing plate and a broadband wavelength plate. In the above two geometries, the external light reflection spectrum is as shown in FIG.

Next, as described above, the linear polarizers 20 and 2
By using the light-emitting element that is the light-emitting layer 14 such that g ≠ 0 by using the two retardation plates 18a and 18b, the emitted light can be more efficiently emitted than when the light-emitting layer that emits non-polarized light is used. FIG. 13 shows the reason why g <0.
Based on FIG. 14, the case where g> 0 will be described with reference to FIG. 13 and 14, the same reference numerals as those in FIG. 8 indicate the same components.

First, FIG. 13 shows the case where g <0.
It will be described with reference to FIG. The light is emitted from the light emitting layer 14 and the light is emitted.
Suppose that the intensity of light traveling to
For example, if the light intensity ratio is I_L= 0.2I, I_R= 0.8I
And Delay of the second retardation plate (λ / 2 plate) 18b
The angle between the phase axis and the transmission axis of the linear polarizer 20 is + 15 °.
Then, the slow axis of the first retardation plate (λ / 4 plate) 18a and
The angle between the transmission axes of the linear polarizer 20 is + 75 °.
Left circular polarization component I_LAre the first and second phase difference plates 18a, 1
8b, the transmission axis of the linear polarizer 20
Since the light becomes vertical linearly polarized light, it is absorbed by the linearly polarizing plate 20.
Will be collected. On the other hand, the right circular polarization component I _RIs the first and second
By passing through the two retardation plates 18a and 18b,
Since the light becomes linearly polarized light parallel to the transmission axis of the linearly polarizing plate 20,
Processes when there is no light absorption in the transmission axis direction of the linear polarizing plate 20
And the light of intensity 0.8I passes through the polarizing plate and exits.
Become.

Next, the case where g> 0 will be described with reference to FIG. Emitted from the light emitting layer 14, the intensity of light traveling in the light emitting direction is to be I, the intensity ratio of the right circularly polarized light and left circularly polarized light is at _{I L = 0.8I, I R =} 0.2I as an example And Assuming that the angle between the slow axis of the second retardation plate 18b and the transmission axis of the linear polarizing plate 20 is + 75 °, the angle between the slow axis of the first retardation plate 18a and the transmission axis of the linear polarizing plate 20 Is + 195 °. Right circularly polarized light component I _R, the first, since the second retardation plate 18a, passes through the 18b, the transmission axis of the linear polarizer 20 and the linearly polarized light perpendicular, is absorbed by the linear polarizer 20 . On the other hand, the left circularly polarized light component _IL is the first and second retardation plates 18a and 18a.
8b, the light becomes linearly polarized light parallel to the transmission axis of the linearly polarizing plate 20. Therefore, if there is no light absorption in the transmission axis direction of the linearly polarizing plate 20, light having an intensity of 0.8I is converted to a linearly polarizing plate. The light will pass through and be emitted.

On the other hand, when the light emitting layer emits unpolarized light,
Assuming that the intensity I of light traveling in the light emission direction is 5
Since the light is absorbed by 0%, only light having an intensity of 0.5I is emitted. According to the above principle, by using a light-emitting element using two retardation plates according to one aspect of the present invention, emitted light can be effectively used. Therefore, the light-emitting element using two retardation plates according to one aspect of the present invention can further suppress the reflection of external light and can emit unpolarized light as compared with the case where one retardation plate is used. Emitted light can be emitted to the outside more efficiently than when a layer is used.

In the present invention, the number of retarders is not limited to two, and the number of retarders is not limited as long as the whole of the plurality of retarders is configured to be a broadband λ / 4 plate. In general, if the number is increased, the band can be broadened more with respect to the wavelength.

[0040]

Example 1 Poly {2,5-bis [(S) -2-methylbutox] was used as a circularly polarized light emitting material.
y] -1,4-phenylene} vinylene} -co-{[2,5-bis [(3R, 3S)-
(3,7-dimethyloctyl) oxy] -1,4-phenylene] vinylene} was synthesized. This is chloroform: 0-dichlorobenzene =
A solution obtained by mixing a 7: 1 solution at a ratio of 4 mg / mL was prepared, and this was spin-coated in a nitrogen atmosphere on a glass substrate on which a 1000 ° -thick ITO film was formed by sputtering. After baking at 60 ° C. to evaporate the solvent, an aluminum electrode was formed thereon by vapor deposition.

When a voltage of 20 V was applied using the ITO side of the element as an anode and the aluminum side as a cathode, the g value was 6 wavelengths.
The emission light at 00 nm was -1.1 × 10 ^-1 . From this value, it is calculated that if the intensity of light having a wavelength of 600 nm is normalized to 1, I _L = 0.47 and I _R = 0.53. A retardation plate and a linear polarizing plate were attached to this light emitting element so as to have the geometry shown in FIG. At this time,
The phase difference of the retardation plate is λ /
The thickness was set to 150 nm so as to satisfy the four-plate condition, and the angle between the slow axis of the retardation plate and the transmission axis of the polarizing plate was + 45 °. A transmission axis direction of the transmittance of the linearly polarizing plate is 80%, since 98% transmittance of the phase difference plate, when emitted at a ratio of I _L and I _R as described above, passes through the linearly polarizing plate Coming strength is
It should be 0.415 from the calculation. When actually measured, it was 0.420, which almost coincided with the calculation. If the light emission is assumed to be non-polarized, the intensity should be 0.392. From the above results, the combination of the light emitting layer that emits circularly polarized light with g ≠ 0, the retardation plate, and the polarizing plate allows the non-polarized light emission. It was found that the emitted light could be extracted more efficiently than when the layer was used. The reflection spectrum of external light is shown in FIG.
And external light was also sufficiently prevented from being reflected.

Example 2 A first retardation plate, a second retardation plate, and a linear polarizing plate were attached to the device manufactured in Example 1 so as to have a geometry shown in FIG. At this time, the phase difference of the first retardation plate is set to 150 nm so as to satisfy the λ / 4 plate condition with respect to the light having the wavelength of 600 nm, and the phase difference of the second retardation plate is set with respect to the light having the wavelength of 600 nm. Λ / 2 plate condition
00 nm. The angle between the slow axis of the second retardation plate and the transmission axis of the linear polarizing plate is + 15 °, and the angle between the slow axis of the first retardation plate and the transmission axis of the linear polarizing plate is + 75 °.
And A transmission axis direction of the transmittance of the linearly polarizing plate is 80%, since 98% transmittance of the phase difference plate, when emitted at a ratio of I _L and I _R as described above, passes through the linearly polarizing plate The coming intensity should be 0.407 from the calculation. When actually measured, it was 0.413, which almost coincided with the calculation.
If the light emission is assumed to be non-polarized, the intensity should be 0.384, so from the above results, by combining a light emitting layer that emits circularly polarized light with g ≠ 0, two retardation plates, and a polarizing plate, It was found that the emitted light could be extracted more efficiently than when the non-polarized light emitting layer was used. Further, the reflection spectrum of the external light was as shown in FIG. 12, and the external light in a wide wavelength range was sufficiently prevented from being reflected.

In the embodiments of the present invention, the organic EL layer is used as the light emitting layer. However, it is important to emit light with g ≠ 0. A light-emitting body having such a light-emitting principle may be used.

[0044]

As described above, the present invention provides a light emitting layer which emits circularly polarized light having different intensities of left and right circularly polarized lights, in other words, g
Combining a circularly polarizing plate with a light-emitting layer that emits light of ≠ 0 can prevent external light reflection, and takes out emitted light more efficiently than when using a light-emitting layer that emits non-polarized light. be able to.

In a preferred embodiment of the present invention, the circularly polarizing plate comprises a retardation plate and a linearly polarizing plate. Further, according to one aspect of the present invention, in the case where the circularly polarizing plate includes the first retardation plate, the second retardation plate, and the linearly polarizing plate, the outside light having a wider wavelength range than when using one retardation plate. Reflection can be prevented, and the emitted light can be extracted to the outside more efficiently than when a light-emitting layer that emits non-polarized light is used.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an organic EL device in which a light emitting layer that emits circularly polarized light, a retardation plate, and a linearly polarizing plate are combined according to a preferred embodiment of the present invention.

FIG. 2 is a diagram showing an optical geometry when g <0 in the structure of FIG. 1;

FIG. 3 is a diagram showing an optical geometry when g> 0 in the structure of FIG. 1;

FIG. 4 shows a calculation result of external light reflectance (%) when θ is changed from 30 ° to 60 ° when g <0 in the structure of FIG. 1;

FIG. 5 shows that in the two geometries of FIGS. 2 and 3, θ is + 40 ° ≦ θ ≦ + 50 ° and + respectively.
The external light reflection spectrum when it is in the range of 130 ° ≦ θ ≦ + 140 ° is shown.

FIG. 6 is a diagram showing how the polarization state of emitted light is modulated when g <0 in the structure of FIG. 1;

FIG. 7 is a diagram showing a state in which the polarization state of emitted light is modulated when g> 0 in the structure of FIG. 1;

FIG. 8 illustrates another preferred embodiment of the present invention.
FIG. 2 is a cross-sectional view of an organic EL element in which a light emitting layer that emits circularly polarized light, a first retardation plate, a second retardation plate, and a linear polarizing plate are combined.

FIG. 9 is a diagram showing an optical geometry when g <0 in the structure of FIG. 8;

FIG. 10 is a diagram showing an optical geometry when g> 0 in the structure of FIG. 8;

FIG. 11 shows a graph of FIG. 8 when g <0;
The calculation results of the external light reflectance (%) when θ ₂ is changed from 0 ° to 30 ° are shown.

FIG. 12 shows that θ ₂ is + 10 ° ≦ θ ₂ ≦ + 20 ° in each of the _two geometries of FIGS. 9 and 10;
And the external light reflection spectrum when + 70 ° ≦ θ ₂ ≦ + 80 °.

FIG. 13 is a diagram showing how the polarization state of emitted light is modulated when g> 0 in the structure of FIG. 8;

FIG. 14 is a diagram showing how the polarization state of emitted light is modulated when g <0 in the structure of FIG. 8;

FIG. 15 is a sectional view of a structure of a general organic EL element.

FIG. 16 is a cross-sectional view of one conventional organic EL element having a configuration for suppressing reflection of external light.

FIG. 17 is a cross-sectional view of another conventional organic EL element having a configuration for suppressing reflection of external light.

[Explanation of symbols]

 Reference Signs List 10 glass substrate 12 anode 14 light emitting layer 16 cathode 18 retardation plate 18a first retardation plate (λ / 4 plate) 18b second retardation plate (λ / 2 plate) 20 linear polarizing plate 22 circular polarizing plate

Claims (5)

[Claims] 1. A light emitting device comprising: a light emitting layer that emits circularly polarized light having different intensities of left and right circularly polarized lights; and a circularly polarizing plate. 2. The circularly polarizing plate includes a retardation plate and a linearly polarizing plate, the light emitting layer, the retardation plate and the linearly polarizing plate are arranged in this order, and the retardation plate is substantially arranged. a λ / 4 plate, when facing the light emitting surface, when the counterclockwise direction is +, when the right circularly polarized light is stronger than the left circularly polarized light, the slow axis of the phase difference plate and the straight line Angle θ between transmission axes of polarizing plates
Is within a predetermined angular width centered on +45 degrees, or when the intensity of left circularly polarized light is greater than the intensity of right circularly polarized light, the slow axis of the phase difference plate and the transmission axis of the linearly polarizing plate are formed. Angle θ
The light emitting device according to claim 1, wherein is within a predetermined angular width centered at +135 degrees. 3. The circularly polarizing plate includes a first retardation plate, a second retardation plate, and a linearly polarizing plate, wherein the light emitting layer, the first retardation plate, and the second retardation plate are provided. And the linear polarizing plate is arranged in this order, the first retardation plate is substantially a λ / 4 plate, the second retardation plate is a substantially λ / 2 plate, When facing the light emitting surface, when the counterclockwise direction is +, the angle θ ₁ between the slow axis of the first retardation plate and the transmission axis of the linear polarizer and the angle of the second retardation plate There is a relationship of θ ₁ = 2θ ₂ + 45 ° between the slow axis and the angle θ ₂ formed by the transmission axis of the linear polarizing plate, and the intensity of right circularly polarized light is stronger than the intensity of left circularly polarized light. when, theta ₂ is located in the predetermined angular width around the +15 degrees, or when the intensity of left-handed circularly polarized light is stronger than the strength of the right circularly polarized light, theta ₂ is centered on +75 degrees Light emitting device according to claim 1, wherein a is in a constant angular width. 4. The light emitting device according to claim 2, wherein said predetermined angular width is within 5 degrees. 5. The method according to claim 2, wherein the predetermined angular width is 0 degrees.
Or the light-emitting element according to 3.