Organic light-emitting display panel and manufacturing method thereof

A technology of light-emitting display and organic light-emitting layer, which is applied in semiconductor/solid-state device manufacturing, semiconductor devices, electrical components, etc. The effect of small color shift

Active Publication Date: 2014-10-08
WUHAN TIANMA MICRO ELECTRONICS CO LTD +1
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Problems solved by technology

[0004] However, the disadvantage of the above-mentioned organic light-emitting display panel is that the outgoing light has strong directionality, and the peak wavelength and intensity of the spectrum decrease with the increase of the...
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Abstract

The invention discloses an organic light-emitting display panel and a manufacturing method of the organic light-emitting display panel. The organic light-emitting display panel comprises an upper substrate, a first electrode layer, an organic light-emitting layer, a second electrode layer and a lower substrate, which are sequentially arranged, wherein a refraction layer is arranged on one side, deviating from the organic light-emitting layer, of the first electrode layer and comprises a plurality of convex bodies; each convex body is provided with a sharp corner, and the sharp corner faces the side deviating from the organic light-emitting layer. According to the technical scheme, through the refraction layer with the convex bodies, light emitted by the organic light-emitting layer can be effectively converged, and parallel light is formed within scope of each view angle, so that color offset of view angles is reduced.

Application Domain

Solid-state devicesSemiconductor/solid-state device manufacturing +1

Technology Topic

EngineeringSurface plate +3

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  • Organic light-emitting display panel and manufacturing method thereof
  • Organic light-emitting display panel and manufacturing method thereof
  • Organic light-emitting display panel and manufacturing method thereof

Examples

  • Experimental program(1)

Example Embodiment

[0022] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for ease of description, the drawings only show a part but not all of the structure related to the present invention.
[0023] An embodiment of the present invention provides an organic light-emitting display panel, which includes an upper substrate, a first electrode layer, an organic light-emitting layer, a second electrode layer, and a lower substrate that are sequentially arranged, wherein the first electrode layer faces away from the organic One side of the light-emitting layer is provided with a refraction layer, and the refraction layer includes a plurality of convex bodies, the convex bodies have sharp corners, and the sharp corners face the side away from the organic light-emitting layer.
[0024] The convex body may optionally be a cone, and the sharp angle of the convex body is the apex angle of the cone. The convex bodies given in the embodiment of the present invention are described by taking mutually independent arrangement as an example. However, those skilled in the art will understand that two or more cones can also be partially overlapped and combined to form more than two sharp angles. Alternatively, it can also be other sharp-angled convex structures that can meet the following requirements for refracting light to obtain parallel light to reduce color shift. The sharp angle of the convex body has no arc, and can be a regular pyramid or cone, or it can have an irregular contour.
[0025] By providing a refraction layer including a convex body with sharp corners, the light emitted by the organic light-emitting layer can be effectively converged to form parallel light in each viewing angle range to reduce the color shift of the viewing angle. The detailed principle is explained in conjunction with the drawings. . The shape, size, and layout of the convex body can be implemented in multiple ways, which will be described separately through embodiments below.
[0026] figure 2 It is a schematic side sectional view of an organic light emitting display panel provided by an embodiment of the present invention, such as figure 2 As shown, the organic light emitting display panel includes an upper substrate 201, a first electrode layer 202, an organic light emitting layer 203, a second electrode layer 204, and a lower substrate 205. The first electrode layer 202 is typically a cathode layer, and the second electrode layer 204 is typically an anode layer. Specifically, the first electrode layer 202 is formed on the lower surface of the upper substrate 201, the second electrode layer 204 is formed on the upper surface of the lower substrate 205, and the organic light emitting layer 203 is sandwiched between the first electrode layer 202 and the second electrode layer 204. between. The organic light-emitting layer 203 may be composed of a multi-layer pattern according to actual needs, and can emit light under electric field excitation. The embodiment of the present invention does not limit the specific hierarchical structure of the organic light-emitting layer 203. Optionally, the light may be emitted from the upper surface of the organic light emitting layer 203 toward the upper substrate 201.
[0027] For a typical top emission organic light emitting display panel, optionally, it further includes a cover layer 207 and an air layer 206, the cover layer 207 covers the first electrode layer 202, and the air layer 206 is encapsulated on the cover layer 207 and the upper substrate 201 between. The air layer 206 may be encapsulated between the cover layer 207 and the upper substrate 201 by a frit (Frit) glue 208. The capping layer 207 (capping layer) above the first electrode layer 202 has a higher refractive index, so the first electrode layer 202, the capping layer 207 and the air layer 206, these three layers make the reflectance of the first electrode layer 202 lower. The original microcavity effect is weakened, which can reduce the visual role deviation to a certain extent. Of course, those skilled in the art can understand that the cover layer 207 and the air layer 206 may not be provided in the organic light-emitting display panel, and the refractive layer formed by the convex body can also achieve the effect of reducing the viewing angle deviation, and can save the production cost. The material cost of the refractive index covering layer 207.
[0028] In the above organic light-emitting panel, the first electrode layer 202 is further provided with a refractive layer facing the side away from the organic light-emitting layer 203. The refractive layer includes a plurality of cones 209, and the top corners of the cones 209 are away from the organic light-emitting layer 203. That is, the cone 209 is formed on the side where the organic light emitting panel displays to the user. The embodiment of the present invention will take the cone 209 as the convex body as an example for description, and convex bodies of other shapes are also applicable.
[0029] Optionally, the refraction layer is provided on the upper surface of the upper substrate 201, and the convex body of the refraction layer is formed on the upper surface of the upper substrate 201, and the structure between the upper substrate 201, the first electrode layer 202 and the organic light emitting layer 203 The impact is small, and the process is simple to implement. Optionally, the convex body such as the cone 209 in the refractive layer is a convex embossed on the upper surface of the upper substrate 201. That is, first provide a stamper with a large number of cones 209 contour pattern structure, and secondly provide a low-refractive index film layer, which is a thermoplastic material, contact the film layer with the stamper, heat and apply pressure, the cone The contour structure pattern of the body 209 is fully pressed into the film layer, cooled and peeled off to obtain the cone 209 structure. Finally, the cone 209 structure is pressed and printed on the upper substrate 1 to form a cone 209-shaped protrusion. The process is simple and easy to implement.
[0030] For the cone 209 formed on the upper surface of the upper substrate 201, optionally, the refractive index of the material of the cone 209 is smaller than the refractive index of the material of the upper substrate 201. In this way, at the interface between the cone 209 and the upper substrate 201, total reflection of the emitted light can be avoided, and it can be ensured that all the light can be emitted as much as possible.
[0031] The cone is preferably a cone, which can provide uniform light refraction processing at each viewing angle, so that the viewing effect of each viewing angle is consistent. For example, compared with the elongated grid-shaped protrusions, the dimensions of the grid-shaped protrusions in the length direction and the width direction are significantly different. It is an incompletely symmetric structure and cannot uniformly improve the color shift in all viewing angle directions; in addition, relatively Compared with spherical or hemispherical round protrusions, although the round protrusions have a symmetrical structure, the color purity of light will be greatly reduced. The cone structure in this embodiment can uniformly improve the color shift in all viewing angle directions while ensuring color purity. However, those skilled in the art can understand that the conventional viewing angle is concentrated in a certain range in front of the display, so the cone 209 can also be designed as a pyramid, such as a triangular pyramid, a quadrangular pyramid, etc., to meet the adjustment of the color shift within the main viewing angle range. .
[0032] Optionally, the organic light emitting display panel can choose the same material as the upper substrate 301 to prepare the cone 309, such as image 3 Shown.
[0033] Such as Figure 4 Shown is a schematic diagram of optical principles applicable to the embodiments of the present invention. Optionally, the apex angle of the triangular cone 409 ranges from 120° to 160°, and optionally, the angle is 120°. The refractive index of the cone 409 material is smaller than that of the substrate material. Taking fluoropolymer as an example, the apex angle is 120°.
[0034] Such as Figure 4 As shown, when the light with the angle θ1 (the following angles are the included angle between the light and the interface normal) is incident on the left side of the cone 409, the angle of the outgoing light is θ5; when the light with the angle θ2 is incident on When the cone 409 is on the right side, the angle of the outgoing light is θ6. Under the appropriate θ1 and θ2, the two outgoing rays can be converted into parallel rays and exit. When the human eye looks at the screen along the direction of the parallel rays, the Chromaticity is the mixed chromaticity of two incident rays, and the perceived brightness is the mixed brightness of the two incident rays.
[0035] Set the viewing angle of the display from -90° to 90°. Among them, -60° to 60° is the main viewing range, which is also the focus of attention. The other angles are not considered for the time being. Since -60° to 0° and 0° to 60° are symmetrical, the following analysis focuses on the change of light in the viewing angle range of 0° to 60°.
[0036] Table 1
[0037]
[0038] Table 1 shows the Figure 4 The organic light-emitting display panel of the structure shown is calculated based on the data. Through calculation, it is found that when the angle of the parallel light viewed by the viewing angle increases from 0° to 60°, the average incident angle range is reduced to 8° to 33° °. The range of the angle of incidence observed within the viewing angle is reduced, so that the peak wavelength and intensity change of this part of the light spectrum are reduced, and the color shift is correspondingly reduced.
[0039] Even if the light passes through the cone to a certain extent, the color shift can be reduced because the cone structure modulates the spectral peak distribution. Figure 5a-5c It is a computer-simulated graph of the relative brightness value changes of the three colors of RGB in different viewing angles of the organic light-emitting display panel shown in the embodiment of the present invention. The abscissa in each figure is the viewing angle, and the ordinate is the brightness value. The relative brightness value of a unified processing. Each figure shows the relative brightness of the two organic light-emitting display panels with and without cones as a function of viewing angle. It can be seen that in the case of the cone structure, the three colors of RGB The brightness of the light is higher in the case of a small viewing angle, that is, the light is concentrated to a certain extent. Figure 6a-6c It is a computer-simulated color shift curve diagram of the organic light emitting display panel shown in the embodiment of the present invention of RGB three colors at different viewing angles. In the figure, the abscissa is the viewing angle, and the ordinate is the color shift value. The color shift is the change in the color coordinate relative to the 0° direction under a certain viewing angle in a uniform color space. For RGB, the color shift at 60° viewing angle should be controlled within 0.08. It can be seen that with a cone structure, when the viewing angle is small, the color shift effect is not obvious, but after the viewing angle is increased to 50°, the color shift Significant improvement. At a viewing angle of 60°, the color shift of the three colors of RGB light is reduced to below 0.08. So the cone structure is applicable to all three colors of RGB.
[0040] The arrangement position of the cone can also have various changes. Optionally, the refractive layer can also be arranged on the lower surface of the upper substrate.
[0041] Specific, such as Figure 7 As shown, the cone 709 in the refractive layer may be a protrusion imprinted on the lower surface of the upper substrate 701. In this manner, the top end of the cone 709 can be embossed toward the lower surface of the upper substrate 701.
[0042] Or like Figure 8 As shown, the cone 809 in the refractive layer may be a groove opened on the lower surface of the upper substrate 801. By opening the groove to form the cone, it is not necessary to add a convex cone, so material can be saved. At the same time, the groove starts to be inside the upper substrate, which can also save space.
[0043] Or, as Picture 9 As shown, the cone 909 in the refraction layer may be a groove opened in the refraction plate 9010 adjacent to the lower surface of the upper substrate 901. The refraction plate 9010 can be made of the same or different material as the upper substrate 901. A cone 909-shaped groove is formed in the refraction plate 9010, and the refraction plate 9010 is fixed to the lower surface of the upper substrate 901 by bonding or other means. .
[0044] In the case where a cover layer is formed in the organic light emitting display panel, the cone may also be formed based on the cover layer. The cone is formed adjacent to the cover layer, and the light can be refracted immediately after the light exits. At the same time, based on the cover layer setting, the outer side of the cone is further protected by the upper substrate, which can maintain the shape of the cone to a greater extent. Reduce the possibility of deformation and ensure the refraction effect.
[0045] Such as Picture 10 As shown, the cone 1009 of the refractive layer is a protrusion imprinted on the upper surface of the cover layer 1007.
[0046] Or like Picture 11 As shown, the cone 119 of the refractive layer is a protrusion imprinted on the lower surface of the cover layer 117.
[0047] Or, as Picture 12 As shown, the cone 129 in the refractive layer is a groove opened on the lower surface of the cover layer 127.
[0048] The layout of the cones in the refractive layer can also be implemented in multiple ways. The cones are typically evenly arranged to effectively refract the light of the entire panel.
[0049] Optionally, each sub-pixel in the panel is arranged corresponding to the position of at least one cone. Such as Figure 13 Shown is a schematic top view of a partial structure of an organic light emitting display panel provided by an embodiment of the present invention. Pixel units are usually formed in the electrode layer of the panel, and each pixel unit includes multiple sub-pixels of different colors, usually red sub-pixel 11, green sub-pixel 12 and blue sub-pixel 13, which can independently control the display of sub-pixels Grayscale. Within the area occupied by each sub-pixel, one or more cones 139 are correspondingly provided. Since the sub-pixels of different colors are independently controlled, the emitted light may not be synchronized. Each sub-pixel is refracted by its corresponding cone 139, which can better provide refraction processing for each color of light.
[0050] In addition, due to the different wavelengths of light of different colors, the angle of refraction formed in the cone 139 is not completely the same. Therefore, it is preferable that the apex angles of the cones 139 corresponding to the sub-pixels of different colors are different to meet the refraction requirements of the light emitted by the sub-pixels of different colors, to reduce the color shift as much as possible, and to make the brightness of different colors consistent.
[0051] Under normal circumstances, the refractive index of the material to different colors of light is somewhat different. When the cone 139 uses a polymer material, its refractive index for blue light (peak wavelength is 460) is 1.54, and for green light (peak wavelength is The refractive index of 520) is 1.45, and the refractive index for red light (peak wavelength of 615) is 1.38. For the cone 139 with an apex angle of 120°:
[0052] When the red light passes through this structure, the 16.43° long wave and the 51.24° short wave are converted into two 60° parallel lights through refraction, with an average incident angle of 33°;
[0053] When the green light passes through this structure, the long wave of 12.43° and the short wave of 50.17° are converted into two 60° parallel lights through refraction, and the average incident angle is 31°
[0054] When the blue light passes through this structure, the 7.43° long wave and the 48.94° short wave are converted into two 60° parallel lights through refraction, and the average incident angle is 28°
[0055] Therefore, the same cone structure is the best to improve the color shift of the blue light with the shortest wavelength, followed by green light, and finally red light. Therefore, the apex angle of the cone can be set according to the difference in the wavelength of the light of different colors, or the apex angle of the cone can be set according to the demand for improving the color shift of the light of different colors.
[0056] The convex bodies arranged on the panel are preferably adjacent to each other without gaps, and there is no space between the convex bodies. However, due to the limitation of the manufacturing process, in fact, there are often intervals between the convex bodies formed according to the seamless standard, and the interval is generally smaller than the size level of the convex bodies. The size level of the convex body is preferably consistent with the size level of the pixel. In the micron level, for example, the radius of the bottom surface of the cone is 5-10 microns. The gap size due to process errors is usually on the nanometer level. The light emitted from the gap at this level will diffract with the light emitted from the position of the convex body, and the display effect is not good. Therefore, in actual production, it is possible to design the gap size between adjacent convex bodies to be the same size level as the convex body size. Preferably, the gap size and the convex body size are both on the micron level. In this way, the probability of diffracting the light rays emitted by the intervals and convex bodies of the same size level is significantly reduced.
[0057] The embodiment of the present invention also provides a method for manufacturing an organic light emitting display panel, the method including:
[0058] A refraction layer is provided on the side of the first electrode layer away from the organic light-emitting layer, wherein the refraction layer includes a plurality of cones, and the apex angle of the cones faces the side away from the organic light-emitting layer.
[0059] The manufacturing method can be used to manufacture the organic light emitting display panel provided by any embodiment of the present invention. The convex body may be a cone, and the sharp angle of the convex body is the apex angle of the cone. The cone formed is preferably a cone.
[0060] For cones with different placement positions, the operation of disposing a refractive layer on the side of the first electrode layer away from the organic light-emitting layer can be implemented in different ways, including at least one of the following:
[0061] On the upper surface of the upper substrate on the side of the first electrode layer facing away from the organic light-emitting layer, using a thermoplastic embossing process to form protrusions as the protrusions;
[0062] On the lower surface of the upper substrate on the side of the first electrode layer away from the organic light emitting layer, a thermoplastic embossing process is used to form protrusions as the protrusions;
[0063] On the lower surface of the upper substrate on the side of the first electrode layer away from the organic light-emitting layer, an etching process is used to form a groove as the convex body;
[0064] In the refraction plate adjacent to the lower surface of the upper substrate on the side of the first electrode layer away from the organic light-emitting layer, an etching process is used to form a groove as the convex body;
[0065] On the upper surface of the covering layer on the side of the first electrode layer away from the organic light-emitting layer, using a thermoplastic embossing process to form protrusions as the protrusions; or
[0066] On the lower surface of the covering layer on the side of the first electrode layer away from the organic light-emitting layer, a thermoplastic embossing process is used to form protrusions as the protrusions; or
[0067] On the lower surface of the cover layer on the side of the first electrode layer away from the organic light-emitting layer, an etching process is used to form grooves as the convex bodies.
[0068] In the organic light emitting display panel provided by the embodiment of the present invention, a plurality of convex structures are arranged on the outer side of the organic light emitting layer facing the display direction. When two beams of light emitted from different angles of the organic light emitting layer pass through the convex structure, the light Will be converted into two parallel beams of light emitted into the air. When the human eye looks at the screen in the direction of parallel light, the chromaticity perceived by the human eye is a mixed spectrum of the short-wave spectrum and the long-wave spectrum, which can reduce the visual role deviation under the large viewing angle. This solution is particularly significant in improving the visual deflection of red light.
[0069] The convex body of the present invention can be formed at any position above the cathode layer, and is not limited to the positions listed in the examples of this application document. In addition, the convex body of the present invention may be formed on the refracting plate alone, or may be formed in any layer above the cathode layer. As long as it is a convex structure arranged above the cathode layer that can adjust the direction of light, it is included in the idea of ​​the present invention. The convex body forming methods listed in the present invention include, but are not limited to, several methods listed in this application document. As long as they are processing methods used in the prior art or in the art, they are all included in the idea of ​​the present invention.
[0070] Note that the above are only the preferred embodiments of the present invention and the applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made to those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope of is determined by the scope of the appended claims.

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PropertyMeasurementUnit
Base radius5.0 ~ 10.0µm

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