JP2020017349A - Organic EL display panel - Google Patents

Abstract

To provide an organic EL display panel excellent in suppression of color shift according to gaze direction.SOLUTION: An organic EL display panel 1 includes light emission parts 2R, 2G, 2B provided on a first board separately from each other, and emitting light with different colors respectively and a visible light absorption layer 16 provided on a second board placed oppositely to the first board, and having an opening 16a at the corresponding positions of the light emission parts 2R, 2G, 2B. Each of the light emission parts 2R, 2G, 2B has main emission areas 3R, 3G, 3B emitting light with a substantially constant brilliance in the central part, and the light emission part 2R, 2G, 2B having a larger main emission areas 3R, 3G, 3B has a larger opening 16a at the corresponding position of the visible light absorption layer 16.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an organic EL (Electro-Luminescence) display panel.

  The organic EL display panel is configured by arranging a plurality of light emitting units that can independently control light emission for each pixel on a substrate. 2. Description of the Related Art An organic EL display panel capable of emitting multicolor light (hereinafter, referred to as a color organic EL display panel) has a plurality of light-emitting portions that emit light of different colors (different wavelengths) such as blue, green, and red, arranged on a substrate. It is constituted by a regular arrangement.

  2. Description of the Related Art In an organic EL display panel, there is a structure in which a visible light absorbing material (a so-called black matrix) for suppressing external light reflection is arranged between adjacent light emitting units. While the black matrix improves the display contrast, it may cause a color shift in which the same display color has a different chromaticity depending on the viewing direction.

  A technique for suppressing color shift caused by a black matrix is known (for example, Patent Document 1). Japanese Patent Application Laid-Open No. H11-163873 specifies a preferable dimensional condition of a black matrix for suppressing color misregistration depending on a viewing direction in a color organic EL display panel based on a size of a light emitting area. In this specification, the black matrix is referred to as a visible light absorbing layer.

JP 2010-118273 A

  However, in the conventional technique, the effect of suppressing color misregistration according to the line of sight direction is not sufficient.

  Therefore, an object of the present invention is to provide an organic EL display panel that is excellent in suppressing color misregistration depending on the line of sight.

  In order to achieve the above object, one embodiment of an organic EL display panel according to the present invention includes a plurality of light-emitting portions provided on a first substrate so as to be separated from each other and emitting light of different colors, A visible light-absorbing layer provided on a second substrate arranged to face each other and having an opening at a corresponding position of each of the plurality of light-emitting portions, wherein each of the plurality of light-emitting portions is substantially at a central portion. The light-emitting portion has a main light-emitting area that emits light at a constant luminance, and the light-emitting portion having a larger main light-emitting area has a larger opening at a position corresponding to the visible light absorbing layer.

  The light-emitting portion using the organic light-emitting material has a main light-emitting region that emits light with substantially constant luminance at the center, and the peripheral portion located outside the main light-emitting region has low luminance. This is considered to reflect the distribution of the driving current.

  The main light emitting region is a portion that substantially contributes to the overall luminance of the light emitting unit. The main light emitting area may be defined as, for example, a portion that emits light at a luminance that is equal to or higher than the middle between the maximum luminance and the minimum luminance in the light emitting unit, and a luminance that is equal to or more than a predetermined ratio (for example, 80%) of the maximum luminance in the light emitting unit. May be defined as a portion that emits light.

  The size of the main light-emitting area occupying the light-emitting portion differs for each light-emitting color. Therefore, when the visible light absorbing layer is provided with a size based on the light emitting portion, the size of the main light emitting region shielded by the visible light absorbing layer varies for each emission color. For example, when light-emitting portions of different emission colors are viewed in the same oblique direction, a light-emitting portion having a larger main light-emitting region has a greater portion of the main light-emitting region shielded by the visible light absorbing layer, which may cause a problem. Color shift occurs.

  Therefore, with the above-described configuration, a light emitting portion having a larger main light emitting region is provided with a larger opening at a corresponding position of the visible light absorbing layer. This suppresses variations in the size of the portion of the main light-emitting region shielded by the visible light absorbing layer for each light-emitting color, so that an organic EL display panel that is excellent in suppressing color misregistration depending on the line of sight can be obtained. .

  Further, when the plurality of light-emitting portions are viewed in the same oblique direction, portions of the main light-emitting region of each light-emitting portion having the same ratio may be shielded by the visible light absorbing layer.

  According to such a configuration, when the organic EL display panel is viewed in an oblique direction, the ratio of the portion of the main light-emitting region shielded by the visible light absorbing layer becomes the same between the light-emitting colors, so Color shift can be more accurately suppressed.

  In addition, the plurality of light emitting units include a first light emitting unit that emits red light, a second light emitting unit that emits green light, and a third light emitting unit that emits blue light, and the visible light absorbing layer Has a first opening, a second opening, and a third opening at a corresponding position of the first light emitting unit, a corresponding position of the second light emitting unit, and a corresponding position of the third light emitting unit, respectively. May be larger than the second opening, and the second opening may be larger than the third opening.

  According to such a configuration, in a practical organic EL display panel in which the size of the main light-emitting area occupying the light-emitting portion is larger in the order of red, green, and blue, it is possible to appropriately suppress the color shift according to the line of sight.

  ADVANTAGE OF THE INVENTION According to the organic EL display panel which concerns on this invention, the organic EL display panel excellent in the suppression of the color shift according to a gaze direction is obtained.

FIG. 2 is a plan view schematically showing an example of the structure of a general organic EL display panel. Sectional view schematically showing an example of the structure of a general organic EL display panel Sectional view schematically showing an example of the structure of a general organic EL display panel Graph showing an example of actual measurement of the luminance ratio for each emission color according to the viewing direction Graph showing an example of actual measurement of the luminance ratio for each emission color according to the viewing direction Graph showing actual measurement examples of chromaticity values according to the line of sight Schematic diagram for explaining the luminance distribution in the light emitting unit FIG. 2 is a plan view schematically showing an example of the structure of the organic EL display panel according to the embodiment. FIG. 2 is a schematic diagram illustrating an example of dimensions of a main part of an organic EL display panel according to an embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement of constituent elements, connection forms, and the like shown in the following embodiments are merely examples, and do not limit the present invention.

(Embodiment)
The organic EL display panel according to the embodiment is an organic EL display panel that is excellent in suppressing color misregistration in accordance with the direction of the line of sight. It is distinguished from the panel.

  As a preparation, first, the shape of the visible light absorbing layer in the conventional organic EL display panel is clarified, and then, the characteristic shape of the visible light absorbing layer in the organic EL display panel according to the embodiment is compared with the conventional example. It will be described based on.

  FIG. 1 is a plan view schematically showing an example of the configuration of a conventional general organic EL display panel. As shown in FIG. 1, the organic EL display panel 9 has light emitting units 2R, 2G, and 2B that emit red light, green light, and blue light, respectively, arranged on a substrate 10 at a distance from each other and in a matrix. It is composed. The rectangular line types representing the light emitting units 2R, 2G, and 2B distinguish colors of light emitted from the light emitting units 2R, 2G, and 2B.

  On the front surface of the substrate 10, that is, on the light emission side, a visible light absorbing layer 16 having an opening 16a at a position corresponding to each of the light emitting units 2R, 2G, and 2B is provided. The visible light absorbing layer 16 is provided for the purpose of suppressing external light reflection between adjacent light emitting units and improving display contrast. In FIG. 1, the visible light absorbing layer 16 is shown in gray.

  FIG. 2 and FIG. 3 are cross-sectional views schematically illustrating an example of the configuration of the organic EL display panel 9. 2 and 3 correspond to the cross sections of the line II-II and the line III-III shown in FIG. As shown in FIGS. 2 and 3, the organic EL display panel 9 includes a substrate 10, partition walls 11, light emitting units 2 R, 2 G, 2 B, a sealing resin 15, a visible light absorbing layer 16, and a sealing substrate 17. .

  The partition 11 is provided on the substrate 10. The light-emitting portions 2R, 2G, and 2B of different emission colors are separated by the partition 11 (FIG. 2). The light-emitting portions of the same emission color are separated by a cut in the anode 12 (FIG. 3) or separated by a partition 11 (not shown).

  The light emitting units 2R, 2G, and 2B include an anode 12, a light emitting functional layer 13, and a cathode 14. The light-emitting function layer 13 includes a light-emitting layer (not shown) made of an organic light-emitting material specific to a light-emitting color, and forms the light-emitting layer according to a drive current supplied through the anode 12 and the cathode 14. It emits light of a wavelength (color) according to the organic light emitting material.

  The visible light absorbing layer 16 is provided on the sealing substrate 17 in a lattice shape. The sealing resin 17 provided with the visible light absorbing layer 16 and the substrate 10 provided with the light emitting units 2R, 2G, and 2B are placed in a position where the opening 16a overlaps with the light emitting units 2R, 2G, and 2B. The organic EL display panel 9 is configured by pasting together. Here, the substrate 10 is an example of a first substrate, and the sealing substrate 17 is an example of a second substrate.

  The light-emitting portions 2R, 2G, and 2B are light-emitting regions in which light is emitted according to a drive current. The light-emitting portions 2R, 2G, and 2B, that is, the contour edge of the light-emitting region is defined by, for example, the contour edge of the anode 12.

  The size of the opening 16a of the visible light absorbing layer 16 is determined to have a margin c in the X and Y directions from the contour ends of the light emitting units 2R, 2G, and 2B.

  When the sizes of the light emitting units 2R, 2G, and 2B in the X and Y directions are a0 and b0, respectively, the size A0 of the opening 16a in the X direction is a0 + 2 × c, and the size B0 in the Y direction is b0 + 2 × c. It is.

  In this way, by unifying the margin c from the contour end of each of the light emitting units 2R, 2G, and 2B to the visible light absorbing layer 16, the ends of the light emitting units 2R, 2G, and 2B are shielded by the visible light absorbing layer 16. Can be matched. For example, when the light emitting units 2R, 2G, and 2B are viewed in the same oblique direction, the dimensions (referred to as shielding amounts) of the portions of the light emitting units 2R, 2G, and 2B that are blocked by the visible light absorbing layers 16 are the same. it can. Although not shown, when the thickness of the sealing resin 15 is different at each corresponding position of the light emitting units 2R, 2G, and 2B, the margin is increased as the sealing resin 15 is thicker, so that it is obliquely viewed. The amount of shielding when touched can be made uniform.

  Therefore, according to the organic EL display panel 9 manufactured in accordance with the dimensional conditions shown in FIGS. 1, 2 and 3, the color shift according to the viewing direction should be suppressed.

  However, when an organic EL display panel was prototyped under the dimensional conditions based on such a concept and the luminance of each emission color was measured, it was found that the color misregistration depending on the line of sight was not sufficiently suppressed. Specifically, all the light emitting portions of the prototype organic EL display panel emit light at the maximum luminance (that is, white), and the line of sight is shifted from the front (Z direction) vertically (Y direction) and horizontally (X direction) respectively. When the luminance of red, green, and blue was measured while tilting to ゜, the following measurement results were obtained.

  4A and 4B are graphs showing examples of actual measurement of the luminance ratio according to the viewing direction. FIG. 4A and FIG. 4B show the measurement results when the line of sight is tilted vertically (Y direction) and horizontally (X direction), respectively, for each emission color of red (R), green (G), and blue (B). 2 shows the luminance as viewed from the front, normalized to 1. From FIGS. 4A and 4B, it can be seen that the reduction in the luminance of red is greater when viewed in a horizontally inclined direction than when viewed in a vertically inclined direction.

  FIG. 4C is a graph illustrating an actual measurement example of the chromaticity value according to the viewing direction. In FIG. 4C, the chromaticity of the luminescent color as viewed from the front, the chromaticity of the luminescent color as viewed from 45 ° vertically, and the chromaticity of the luminescent color as viewed from 45 ° horizontal are shown in a CIE1976 UCS (uniform chromatographic scale) chromaticity diagram. It is plotted. From FIG. 4C, it can be seen that both the emission color viewed from the front and the emission color viewed from the vertical 45 ° are located at positions where the saturation is low, and appear almost white or gray. On the other hand, the plot of the emission colors as viewed from the horizontal 45 ° is shifted in the cyan direction, and the effect of the decrease in the luminance of red can be confirmed.

  The present inventor performed microscopic observation of the light emitting portion to investigate the cause of the color shift, and found that each of the light emitting portions 2R, 2G, and 2B had a different luminance distribution in the XY plane.

  FIG. 5 is a schematic diagram for explaining a luminance distribution in the light emitting unit. 5A, 5B, and 5C schematically show luminance distributions in the light emitting units 2R, 2G, and 2B with respect to a cross section in the X direction. Each of the light-emitting portions 2R, 2G, and 2B has main light-emitting regions 3R, 3G, and 3B that emit light with substantially constant luminance in the center portion, and luminance at a peripheral portion located outside the main light-emitting regions 3R, 3G, and 3B. Is low. This is considered to reflect the distribution of the drive current in the XY plane.

  The main light emitting regions 3R, 3G, and 3B are portions that substantially contribute to the overall luminance of the light emitting units 2R, 2G, and 2B, respectively. The main light-emitting areas 3R, 3G, and 3B may be defined as, for example, a portion that emits light at a luminance equal to or higher than the middle between the maximum luminance and the minimum luminance in the light-emitting sections 2R, 2G, and 2B. (For example, 80%) or more.

  The sizes of the main light emitting regions 3R, 3G, 3B occupying the light emitting units 2R, 2G, 2B are different from each other. For example, in the prototype organic EL display panel, the size of the main light emitting areas 3R, 3G, 3B occupying the light emitting sections 2R, 2G, 2B is larger in the order of the main light emitting areas 3R, 3G, 3B.

  Therefore, when the visible light absorbing layer 16 is provided with a size based on the light emitting units 2R, 2G, and 2B, the amount of shielding of the main light emitting regions 3R, 3G, and 3B by the visible light absorbing layer 16 varies for each emission color. For example, when the light-emitting portions 2R, 2G, and 2B are viewed at an oblique angle of 45 degrees in the X direction, the larger the main light-emitting regions 3R, 3G, and 3B, the more portions (the portions hatched to the lower right in FIG. 5). It is shielded by the visible light absorbing layer 16.

  The variation in the shielding amount due to the difference in the size of the main light emitting regions 3R, 3G, and 3B also occurs in the cross section in the Y direction (not shown). Since the extension in the direction is longer than the extension in the X direction, its influence is relatively small.

  This is due to the color misregistration shown in FIGS. 4A, 4B, and 4C, that is, when viewed with a line of sight tilted horizontally (X direction) than with a line of sight tilted vertically (Y direction). This is the cause of the large decrease in red luminance.

  Therefore, in the organic EL display panel according to the embodiment, the light emitting portions 2R, 2G, and 2B having the larger main light emitting regions 3R, 3G, and 3B are provided with the openings 16a at the corresponding positions of the visible light absorbing layer 16 so as to be larger.

  FIG. 6 is a plan view schematically showing an example of the structure of the organic EL display panel according to the embodiment.

  FIG. 7 is a schematic diagram illustrating an example of dimensions of a main part of the organic EL display panel according to the embodiment. FIG. 7 shows a dimension example in the X direction for comparison with FIG.

  The organic EL display panel 1 shown in FIGS. 6 and 7 differs from the organic EL display panel 9 shown in FIGS. 1 and 5 in the shape (dimension conditions) of the visible light absorbing layer 16 in the X direction and the Y direction.

  As shown in FIG. 6, in the organic EL display panel 1, the size of the opening 16 a of the visible light absorbing layer 16 has a margin in the X direction and the Y direction from the contour edge of the corresponding main light emitting region 3 </ b> R, 3 </ b> G, 3 </ b> B. The size is determined by taking e (R), e (G), and e (B). The margins e (R), e (G), and e (B) are set independently in the X and Y directions according to the size of the main light emitting areas 3R, 3G, 3B.

  The contour ends of the main light emitting regions 3R, 3G, 3B are defined in accordance with the definition of the main light emitting regions 3R, 3G, 3B described above. That is, the edge of the contour of the main light emitting areas 3R, 3G, 3B may be, for example, a point where light is emitted at a luminance intermediate between the maximum luminance and the minimum luminance in the light emitting sections 2R, 2G, 2B. It may be a point that emits light with a luminance of a ratio (for example, 80%).

  With reference to FIG. 7, the dimensional conditions of the main part of the organic EL display panel 1 will be described in detail with an example of the dimensional conditions in the X direction. In the following description, the notation “in the X direction” is omitted as appropriate to avoid complication.

  When the size of the main light emitting area 3R is a (R), the size A (R) of the opening 16a at the corresponding position is a (R) + 2 × e (R). The margin e (R) is such that the size of the portion of the main light emitting region 3R that is shielded by the visible light absorbing layer 16 (the portion hatched to the lower right in FIG. 7A) is the size of the main light emitting region 3R. A (R) is determined to be a predetermined ratio k.

  When the size of the main light emitting region 3G is a (G), the size A (G) of the opening 16a at the corresponding position is a (G) + 2 × e (G). The margin e (G) is such that the size of the portion of the main light-emitting region 3G that is shielded by the visible light absorbing layer 16 (the portion hatched to the lower right in FIG. 7B) is the size of the main light-emitting region 3G. A (G) is determined to be a predetermined ratio k.

  When the size of the main light emitting area 3B is a (B), the size A (B) of the opening 16a at the corresponding position is a (B) + 2 × e (B). The margin e (B) is such that the size of the portion of the main light-emitting region 3B that is shielded by the visible light absorbing layer 16 (the portion hatched to the lower right in FIG. 7C) is the size of the main light-emitting region 3B. A (B) is determined to be a predetermined ratio k.

  The above dimensional conditions are based on the light emitting portion, and as the main light emitting regions 3R, 3G, 3B are larger, the margins c (R), c (G) from the contour ends of the light emitting portions 2R, 2G, 2B to the visible light absorbing layer 16 are larger. ) And c (B) are large. The margins c (R), c (G), and c (B) are calculated from the margins e (R), e (G), and e (B) based on the contour ends of the main light emitting regions 3R, 3G, 3B and the light emitting portions 2R, This corresponds to a distance obtained by subtracting the distances d (R), d (G), and d (B) between the contour ends of 2G and 2B.

  According to such dimensional conditions, margins e (R) and e (G) corresponding to the size of the main light emitting regions 3R, 3G, 3G with reference to the respective contour ends of the main light emitting regions 3R, 3G, 3B. , E (B), the size of the opening 16a is determined. In the example of FIG. 7, when the organic EL display panel 1 is viewed at an oblique angle of 45 ° in the X direction, the proportion of the main light-emitting regions 3R, 3G, and 3B blocked by the visible light absorbing layer 16 can be uniform.

  Although not shown, the dimensional conditions in the Y direction are defined based on the same concept, so that when the organic EL display panel 1 is viewed obliquely at 45 ° in the Y direction, the visible light absorbing layer 16 causes the main light-emitting area to fall. 3R, 3G, and 3B can be shielded at the same ratio.

  The direction of the line of sight for unifying the rate at which the main light-emitting regions 3R, 3G, and 3B are shielded by the visible light absorbing layer 16 is not limited to 45 °. For example, in the line of sight direction corresponding to the upper limit of the viewing angle of the organic EL display panel 1, the ratio of blocking of the main light emitting regions 3R, 3G, 3B may be unified.

  According to the dimensional conditions described above, the proportions at which the main light-emitting regions 3R, 3G, and 3B are shielded are made uniform, so that the luminance is increased according to the line-of-sight direction as compared with the conventional configuration in which the light-emitting portions 2R, 2G, and 2B are shielded. The rate of decrease can be more accurately aligned for each emission color. As a result, an organic EL display panel having excellent suppression of color misregistration depending on the line of sight can be obtained.

  As described above, the organic EL display panel according to the embodiment of the present invention has been described, but the present invention is not limited to each embodiment. Unless departing from the spirit of the present invention, various modifications conceivable to those skilled in the art may be applied to the present embodiment, and a form constructed by combining components in different embodiments may be one or more of the present invention. It may be included within the scope of the embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be widely used as an organic EL display panel in various video display devices such as a portable information terminal, a personal computer, and a television receiver.

1, 9 Organic EL display panel 2R, 2G, 2B Light emitting portion 3R, 3G, 3B Main light emitting area 10 Substrate 11 Partition wall 12 Anode 13 Light emitting functional layer 14 Cathode 15 Sealing resin 16 Visible light absorbing layer 16a (for visible light absorbing layer ) Opening 17 Sealing substrate

Claims (3)

A plurality of light-emitting portions provided on the first substrate so as to be separated from each other and emit light of different colors,
A visible light absorbing layer provided on a second substrate disposed to face the first substrate and having an opening at a corresponding position of each of the plurality of light emitting units;
Each of the plurality of light emitting units has a main light emitting area that emits light at a substantially constant luminance in a central portion,
The opening at the corresponding position of the visible light absorbing layer is larger as the main light emitting area is larger,
Organic EL display panel. When the plurality of light emitting units are viewed in the same oblique direction, the same proportion of the main light emitting area of each light emitting unit is shielded by the visible light absorbing layer,
The organic EL display panel according to claim 1. The plurality of light emitting units include a first light emitting unit that emits red light, a second light emitting unit that emits green light, and a third light emitting unit that emits blue light,
The visible light absorbing layer has a first opening, a second opening, and a third opening at a position corresponding to the first light emitting unit, a position corresponding to the second light emitting unit, and a position corresponding to the third light emitting unit, respectively. ,
The first opening is larger than the second opening, and the second opening is larger than the third opening;
The organic EL display panel according to claim 1.

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