TW201511378A - Organic light-emitting device - Google Patents

Abstract

An organic light-emitting device includes a transparent substrate, a first electrode, an organic light-emitting layer, a middle layer and a second electrode. The first electrode is disposed on the transparent substrate. The organic light-emitting layer is disposed on the first electrode to emit light with first, second and third wavelengths, and the first, second and third wavelengths are different from each other. The middle layer is interposed between the transparent substrate and the first electrode, and has a refractive index between that of the transparent substrate and that of the first electrode. The middle layer has a first region, a second region and a third region arranged in a plane direction, which respectively have thicknesses calculated by following formula: d=(2x+1)[lambda]/4n, in which x is 0 or an integer, and [lambda] respectively are the first, second and third wavelengths, and n is the refractive index of the middle layer. The second electrode is disposed on the organic light-emitting layer.

Description

Organic light emitting device

The present invention relates to a light emitting device; and more particularly to an organic light emitting device.

In general, an organic light-emitting device includes a substrate, an anode, a light-emitting layer, and a cathode. The organic light-emitting device has the advantages of uniform light emission and low driving voltage, but its effective light utilization rate is low. This is because the light emitted by the light-emitting layer is easily reflected between the anode and the substrate or between the substrate and the air, and some of the light is confined to the inside of the anode or the substrate to emit light, resulting in low effective light utilization.

In order to solve the above problem, a microstructured optical film may be attached on the outside of the substrate to change the angle of light emission. However, this optical film can only avoid reflection between the substrate and the air, and cannot avoid reflection between the anode and the substrate. Therefore, how to effectively guide light out from the interior of the organic light-emitting device to increase the effective light utilization efficiency of the organic light-emitting device is one of the important research topics at present.

One aspect of the present invention provides an organic light-emitting device including a transparent substrate, a first electrode, an organic light-emitting layer, an intermediate layer, and a second electrode. The first electrode is located above the transparent substrate. The organic light emitting layer is located above the first electrode for emitting light of the first wavelength, the second wavelength, and the third wavelength, and the first wavelength, the second wavelength, and the third wavelength are different from each other. The intermediate layer is sandwiched between the transparent substrate and the first electrode, and the refractive index of the intermediate layer is between the refractive index of the transparent substrate and the refractive index of the first electrode. The intermediate layer has a first zone, a second zone and a third zone arranged in a plane direction, and the thickness d of the first zone, the second zone and the third zone of the intermediate layer is calculated according to the following formula: d=(2x+1)λ/ 4n, where x is 0 or an integer, λ is the first wavelength, the second wavelength, and the third wavelength, respectively, and n is the refractive index of the intermediate layer. The second electrode is located above the organic light emitting layer.

According to an embodiment of the present invention, the organic light emitting layer includes a first portion, a second portion, and a third portion arranged in a planar direction, and the first portion, the second portion, and the third portion are respectively configured to emit the first wavelength, the second wavelength, and the first Three-wavelength light.

According to an embodiment of the invention, the first wavelength is smaller than the second wavelength, and the second wavelength is smaller than the third wavelength.

In accordance with an embodiment of the present invention, the first portion is substantially aligned with the first region of the intermediate layer, the second portion is substantially aligned with the second region of the intermediate layer, and the third portion is substantially aligned with the third region of the intermediate layer.

According to an embodiment of the invention, the first portion is an organic blue light emitting layer, the second portion is an organic green light emitting layer, and the third portion is an organic red light emitting layer.

According to an embodiment of the invention, the thickness of the first zone of the intermediate layer is less than the thickness of the second zone, and the thickness of the second zone is less than the thickness of the third zone.

According to an embodiment of the present invention, the organic light emitting layer includes a first portion, a second portion, and a third portion stacked in a thickness direction, and the first portion, the second portion, and the third portion are respectively configured to emit the first wavelength, the second wavelength, and the first Three-wavelength light.

According to an embodiment of the invention, x is 0, n is 1.643 to 1.732, the thickness of the first region is from about 60.62 to about 63.90 nm, the thickness of the second region is from about 79.39 to about 83.96 nm, and the thickness of the third region is From about 91.22 to about 96.66 nm.

According to an embodiment of the invention, the intermediate layer is an inorganic material comprising alumina, bismuth oxynitride, calcium carbonate, magnesium oxide or a combination thereof.

According to an embodiment of the invention, the refractive index of the transparent substrate is smaller than the refractive index of the first electrode, the first electrode is an anode, and the second electrode is a cathode.

10, 20‧‧‧ Organic light-emitting devices

110‧‧‧Transparent substrate

120‧‧‧Intermediate

120a‧‧‧First District

120b‧‧‧Second District

120c‧‧‧ Third District

130‧‧‧First electrode

140‧‧‧Organic light-emitting layer

140a‧‧‧Part I

140b‧‧‧Part II

140c‧‧‧Part III

150‧‧‧second electrode

160‧‧‧Substrate

D1‧‧‧ thickness of the first zone

D2‧‧‧ thickness of the second zone

D3‧‧‧ thickness of the third zone

D1‧‧‧ plane direction

D2‧‧‧ thickness direction

W1‧‧‧ the width of the first part

W2‧‧‧ width of the second part

W3‧‧‧ the width of the third part

W1‧‧‧ width of the first zone

W2‧‧‧ width of the second zone

W3‧‧‧The width of the third zone

1 is a cross-sectional view showing an organic light-emitting device according to an embodiment of the present invention.

2 is a cross-sectional view showing an organic light-emitting device according to another embodiment of the present invention.

Please refer to FIG. 1. FIG. 1 is a cross-sectional view showing an organic light-emitting device 10 according to an embodiment of the present invention. The organic light-emitting device 10 includes a transparent substrate 110, an intermediate layer 120, a first electrode 130, and an organic light-emitting layer. 140 and a second electrode 150.

The material of the transparent substrate 110 may be glass or plastic. The refractive index of the glass is about 1.52. The plastic may be, for example, Acrylic, Epoxy, Polyethylene terephthalate (PET) or Polycarbonate (PC), and has a refractive index of about 1.49 to Between 1.6.

The first electrode 130 is located above the transparent substrate 110. The material of the first electrode 130 can be, for example, Indium thin oxide (ITO) or other suitable transparent conductive material. The indium tin oxide has a refractive index of between about 1.8 and 2.0. In one embodiment, the materials of the transparent substrate 110 and the first electrode 130 are respectively glass and indium tin oxide, and the refractive index of the transparent substrate 110 (about 1.52) is smaller than the refractive index of the first electrode 130 (about 1.8 to 2.0). between). In the present embodiment, the first electrode 130 serves as an anode and the second electrode 150 serves as a cathode.

The organic light emitting layer 140 is located above the first electrode 130. The organic light emitting device 10 may be an upper light emitting or a lower light emitting structure. In the present embodiment, the light emitted from the organic light-emitting layer 140 emits light in the direction of the transparent substrate 110. The organic light-emitting device 10 can be a color organic light-emitting device, and can be applied to the field of active matrix organic light-emitting diode display (AMOLED).

In the embodiment, the organic light-emitting layer 140 is configured to emit light of a first wavelength, a second wavelength, and a third wavelength, and the first wavelength, the second wavelength, and the third wavelength are different from each other. In terms of the structure of the organic light emitting layer 140, the organic light emitting layer 140 includes a first portion 140a, a second portion 140b, and a third portion. The 140c is arranged along the plane direction D1, and the first portion 140a, the second portion 140b, and the third portion 140c are used to respectively emit light of the first wavelength, the second wavelength, and the third wavelength. In practical applications, the organic light-emitting layer 140 may include more portions for emitting light of other wavelengths to make the color performance of the organic light-emitting device more excellent.

It is to be noted that, in order to prevent the light emitted from the organic light-emitting layer 140 from being reflected between the first electrode 130 and the transparent substrate 110 to cause luminescence loss, the embodiment of the present invention is inserted between the transparent substrate 110 and the first electrode 130. Intermediate layer 120. That is, the intermediate layer 120 is interposed between the transparent substrate 110 and the first electrode 130. Since the refractive index of the intermediate layer 120 is between the refractive index of the transparent substrate 110 and the refractive index of the first electrode 130, reflection of different materials at the interface with each other due to the difference in refractive index can be avoided. In other words, the intermediate layer 120 can guide the excitation light originally confined in the first electrode 130 due to the reflection phenomenon, so that the effective light utilization efficiency of the organic light-emitting device 10 is higher than that of the conventional organic light-emitting device.

However, for the organic light-emitting layer 140 that can emit light of different wavelengths, if the thickness of the intermediate layer is constant (that is, the intermediate layer has only a single thickness), only light of a certain wavelength easily penetrates the intermediate layer to emit light; However, light of other wavelengths may still be internally reflected and not easily emitted, resulting in a color shift phenomenon. For example, for green light with a wavelength of 550 nm, the appropriate thickness of the intermediate layer can be calculated using the formula: d = (2x + 1) λ / 4n, where x is 0 or an integer, λ is 550 nm, and n is the middle. The refractive index of the layer. However, this intermediate layer is only easily penetrated by green light, that is, the reflectance for green light (reflectance, %) It is close to zero or zero; but for red or blue light, the reflectivity of red or blue light is too high, even up to 10%, which causes the organic light-emitting device to produce a significant color shift phenomenon when color is developed.

In order to avoid the occurrence of the above color shift phenomenon, embodiments of the present invention provide an intermediate layer 120 designed for light of different wavelengths. This intermediate layer 120 has a plurality of regions of different thicknesses in response to light of different wavelengths. In the present embodiment, the organic light-emitting layer 140 emits light of the first, second, and third wavelengths, so that the first layer 120a, the second region 120b, and the third region 120c of the intermediate layer 120 having different thicknesses (d) are respectively Corresponding. The thicknesses of the first region 120a, the second region 120b, and the third region 120c are calculated by the following formula (1): d = (2x + 1) λ / 4n (1)

Where x is 0 or an integer, λ is the first wavelength, the second wavelength, and the third wavelength, respectively, and n is the refractive index of the intermediate layer. In several specific embodiments, x is 0, 1, 2, or 3. For example, when x is 1, the thicknesses of the first region 120a, the second region 120b, and the third region 120c are 3×(first wavelength)/4n, 3×(second wavelength)/4n, and 3×, respectively. (third wavelength) / 4n.

In a specific embodiment, the first portion 140a of the organic light emitting layer 140 is an organic blue light emitting layer, the second portion 140b is an organic green light emitting layer, and the third portion 140c is an organic red light emitting layer, and the first wavelength is 420 nm (blue light The second wavelength is 550 nm (green light) and the third wavelength is 632.8 nm (red light). Since the blue light wavelength is smaller than the green light wavelength and the green light wavelength is smaller than the red light wavelength, the thickness d1 of the first region 120a of the intermediate layer 120 is smaller than the thickness d2 of the second region 120b, and the thickness d2 of the second region 120b is smaller than the third region 120c. Thickness d3. In a specific embodiment, the material of the transparent substrate 110 and the first electrode 130 is divided into Other than glass and indium tin oxide, the intermediate layer 120 has a refractive index between about 1.643 and 1.732. Therefore, when x is 0 and n is 1.643 to 1.732, the thickness d1 of the first region 120a is about 60.62 to about 63.90 nm, and the thickness d2 of the second region 120b is about 79.39, as calculated by the above formula (1). Approximately 83.96 nm, the thickness d3 of the third region 120c is from about 91.22 to about 96.66 nm.

The material of the intermediate layer 120 may be an organic material or an inorganic material. In an embodiment, the intermediate layer 120 is made of an inorganic material, which makes it applicable to subsequent anode high temperature processes. For example, the inorganic material may include alumina, bismuth oxynitride, calcium carbonate, magnesium oxide, or a combination thereof, but is not limited thereto. The refractive index of alumina is about 1.606074. The ruthenium oxynitride has a refractive index of from about 1.61917 to about 1.72088. The refractive index of calcium carbonate is about 1.65846. Magnesium oxide has a refractive index of about 1.7375. One or more inorganic materials may be selected depending on the refractive index values of the various inorganic materials to produce an intermediate layer 120 of suitable refractive index.

The manufacturing method of the intermediate layer 120 is, for example, first forming a layer of inorganic material (not shown) on the transparent substrate 110 by chemical vapor deposition or physical vapor deposition, and then performing a Gray-tone mask. The lithography and etching processes are performed to form the intermediate layer 120 having regions of different thicknesses.

In the present embodiment, the first portion 140a of the organic light-emitting layer 140a is substantially aligned with the first region 120a of the intermediate layer 120, the second portion 140b is substantially aligned with the second region 120b of the intermediate layer 120, and the third portion 140c is substantially aligned with the middle The third zone 120c of layer 120. In more detail, the width W1 of the first portion 140a is substantially the same as the width w1 of the first region 120a, the width W2 of the second portion 140b is substantially the same as the width w2 of the second region 120b, and the width W3 and the third portion of the third portion 140c are The width w3 of the region 120c is substantially the same.

The second electrode 150 is located above the organic light emitting layer 140. The material of the second electrode 150 can be a metal or other suitable conductor material. The organic light emitting device 10 may further include another substrate 160 covering the second electrode 150. In order to have good interfacial bonding characteristics between the organic light-emitting layer 140 and the first electrode 130 and the second electrode 150, a buffer layer may be selectively applied between the two. The buffer layer may include an electron injection layer (not shown), a hole injection layer (not shown), an electron conduction layer (not shown), a hole conduction layer (not shown), or a combination thereof, but is not limited thereto.

2 is a cross-sectional view showing an organic light-emitting device 20 according to still another embodiment of the present invention. The organic light-emitting device 20 includes a transparent substrate 110, an intermediate layer 120, a first electrode 130, an organic light-emitting layer 140, and a second electrode 150. The features of the transparent substrate 110, the first electrode 130, and the second electrode 150 may be the same as those of the transparent substrate 110, the first electrode 130, and the second electrode 150 shown in FIG. 1, and thus will not be described herein.

The difference between the organic light-emitting device 20 and the organic light-emitting device 10 is that the organic light-emitting layer 140 of the organic light-emitting device 20 includes a first portion 140a, a second portion 140b, and a third portion 140c which are stacked in the thickness direction D2. The first portion 140a, the second portion 140b, and the third portion 140c are configured to emit light of the first wavelength, the second wavelength, and the third wavelength, respectively. Such an organic light-emitting device 20 can be applied to the field of lighting.

Of course, it should be understood by those of ordinary skill in the art that the intermediate layer 120 of the organic light-emitting device 20 can also be replaced with the intermediate layer 120 of the organic light-emitting device 10.

It can be understood from the above that the organic light-emitting device of the embodiment of the present invention The intermediate layer is disposed between the first electrode and the transparent substrate. The intermediate layer can have different thicknesses according to different emission wavelengths of the organic light-emitting layer, so that light of each wavelength can easily penetrate and emit light, thereby increasing the effective light utilization rate and avoiding the occurrence of color shift phenomenon.

10‧‧‧Organic lighting device

110‧‧‧Transparent substrate

120‧‧‧Intermediate

120a‧‧‧First District

120b‧‧‧Second District

120c‧‧‧ Third District

130‧‧‧First electrode

140‧‧‧Organic light-emitting layer

140a‧‧‧Part I

140b‧‧‧Part II

140c‧‧‧Part III

150‧‧‧second electrode

160‧‧‧Substrate

D1‧‧‧ thickness of the first zone

D2‧‧‧ thickness of the second zone

D3‧‧‧ thickness of the third zone

D1‧‧‧ plane direction

W1‧‧‧ the width of the first part

W2‧‧‧ width of the second part

W3‧‧‧ the width of the third part

W1‧‧‧ width of the first zone

W2‧‧‧ width of the second district

w3‧‧‧The width of the third zone

Claims (10)

An organic light-emitting device comprising: a transparent substrate; a first electrode located above the transparent substrate; an organic light-emitting layer located above the first electrode for emitting a first wavelength, a second wavelength, and a third wavelength The first wavelength, the second wavelength, and the third wavelength are different from each other; an intermediate layer is interposed between the transparent substrate and the first electrode, and the refractive index of the intermediate layer is between the transparent substrate Between the refractive index and the refractive index of the first electrode, wherein the intermediate layer has a first region, a second region, and a third region arranged in a planar direction, the first region, the second region, and the intermediate layer The thickness d of the third region is calculated by the following formula: d = (2x + 1) λ / 4n, where x is 0 or an integer, and λ is the first wavelength, the second wavelength, and the third wavelength, respectively, n is the The refractive index of the intermediate layer; and a second electrode located above the organic light emitting layer. The organic light-emitting device of claim 1, wherein the organic light-emitting layer comprises a first portion, a second portion and a third portion arranged in a planar direction, the first portion, the second portion and the third portion for respectively emitting the Light of the first wavelength, the second wavelength, and the third wavelength. The organic light-emitting device of claim 1, wherein the first wavelength is smaller than the second wavelength, and the second wavelength is smaller than the third wavelength. The organic light-emitting device of claim 2, wherein the first portion is substantially aligned with the first region of the intermediate layer, the second portion is substantially aligned with the second region of the intermediate layer, the third portion is substantially aligned The third zone of the intermediate layer. The organic light-emitting device of claim 4, wherein the first portion is an organic blue light-emitting layer, the second portion is an organic green light-emitting layer, and the third portion is an organic red-emitting light layer. The organic light-emitting device of claim 4, wherein the thickness of the first region of the intermediate layer is less than the thickness of the second region, and the thickness of the second region is less than the thickness of the third region. The organic light-emitting device of claim 1, wherein the organic light-emitting layer comprises a first portion, a second portion, and a third portion stacked in a thickness direction, the first portion, the second portion, and the third portion being used to respectively issue the Light of the first wavelength, the second wavelength, and the third wavelength. The organic light-emitting device of claim 1, wherein x is 0, n is 1.643 to 1.732, the thickness of the first region is about 60.62 to about 63.90 nm, and the thickness of the second region is about 79.39 to about 83.96. The thickness of the third region is about 91.22 to about 96.66 nm. The organic light-emitting device of claim 1, wherein the intermediate layer is an inorganic material comprising alumina, bismuth oxynitride, calcium carbonate, magnesium oxide or a combination thereof. The organic light-emitting device of claim 1, wherein the refractive index of the transparent substrate is smaller than the refractive index of the first electrode, the first electrode is an anode, and the second electrode is a cathode.