JP2011238571A - Display and lens array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that manufacturing the mold of a micro elliptical lens array is difficult and increases the cost while a method is proposed in which an elliptical lens array is provided opposite to a light-emitting material to improve the light collection efficiency of an organic electroluminescent (EL) display.SOLUTION: A display includes pixels that are arranged in an array, and a cylindrical lens array is provided to be opposed to each of the pixel arrays. The cylindrical lens array can be manufactured at relatively low cost, and the collection efficiency of light emitted from an organic EL material can be improved at low cost.

Description

  The present invention relates to a display in which a lens array is arranged so as to face pixels arranged in an array.

  An organic EL display does not require a backlight because the EL material emits light by itself, can be thinned, and is widely used in portable devices and the like. FIG. 10 is a cross-sectional view showing the configuration of the organic EL display. Reference numeral 1001 denotes a substrate, and a TFT is provided on the upper surface thereof. The TFT is not clearly shown in FIG. Reference numerals 1002, 1003, and 1004 denote red, green, and blue organic EL materials, which are formed on the TFT. A transparent electrode made of ITO or the like is formed on the organic EL material, which is not clearly shown in FIG. Reference numeral 1005 denotes a transparent substrate. Since the organic EL material deteriorates due to moisture in the air, it is desirable to use a glass substrate as the transparent substrate 1005. Further, nitrogen or the like is sealed in a region 1006 between the organic EL material (1002 to 1004) and the transparent substrate 1005. More preferably, the region 1006 is filled with resin.

  FIG. 11 is a plan view showing the structure of the organic EL display. The same components as those in FIG. FIG. 11 also does not show the TFT and the transparent electrode. One pixel is composed of a set of red, green, and blue organic EL materials. FIG. 11 shows only two columns in the horizontal direction and three rows in the vertical direction for easy representation, but an actual display is composed of a larger number of pixels.

  FIG. 10 also shows the light emission state from the organic EL material. The light is emitted radially, and light rays 1007 to 1009 indicate light emitted from the red organic EL material 1002. The light emitted from the green organic EL material 1003 and the blue organic EL material 1004 is the same, but is not clearly shown in FIG. A light ray 1007 is light emitted substantially perpendicularly to the surface of the organic EL material 1002. A light ray 1008 is light emitted at an angle with the surface of the organic EL material 1002, and is refracted on the surface of the transparent substrate 1005 and exits from the transparent substrate 1005. These rays 1007 and 1008 reach the eyes of the display viewer. A light ray 1009 is light emitted from the surface of the organic EL material 1002 at a larger angle than the light ray 1008. This light ray 1009 is totally reflected on the surface of the transparent substrate 1005 and does not reach the outside of the transparent substrate 1005 without reaching the outside. Here, a case where the region 1006 is filled with a resin having a refractive index equivalent to that of the transparent substrate 1005 is shown. When the refractive index is about 1.5, total reflection occurs when the incident angle to the transparent substrate 1005 is about 42 degrees or more.

  The organic EL material emits light by applying a voltage. If the applied voltage is high, light is emitted brightly, but the life of the organic EL material is shortened. Although it is desired to reduce the applied voltage in order to extend the life, the amount of light entering the viewer's eyes is reduced because the light is emitted in a radial manner as described above. Furthermore, as can be seen from FIG. 10, the light emitted from the organic EL material with a large angle does not reach the viewer's eyes. Therefore, there is a demand for a method for increasing the light collection efficiency that allows light from the organic EL material to enter the viewer's eyes. As such a method, a method of providing a lens between the organic EL materials 1002 to 1004 and the transparent substrate 1005 has been proposed (see Japanese Patent Application Laid-Open No. 2003-86353).

  FIG. 12 is a cross-sectional view showing the structure of an organic EL display provided with a lens array. The same components as those in FIG. Reference numeral 1010 denotes a lens array substrate. Each lens is disposed above each organic EL material and collects light emitted from the organic EL material. Reference numeral 1011 denotes a light beam emitted from the organic EL material. Although the viewing angle is reduced by using the lens array substrate 1010, a viewer positioned in front of the display can see a bright image. The lens array substrate 1010 must have a higher refractive index than the medium that fills the region 1006.

  FIG. 13 is a plan view showing the structure of the organic EL display shown in FIG. The same components as those in FIG. One pixel is composed of a set of red, green, and blue organic EL materials. FIG. 13 shows only two columns in the horizontal direction and three rows in the vertical direction for easy representation, but the actual display is composed of a larger number of pixels. Also, the ellipses indicated by broken lines are the lenses of the lens array substrate 1010.

  FIG. 14 is a perspective view of a lens array substrate 1010 used in the organic EL display shown in FIGS. Each lens formed in an array has an elliptical shape so as to cover the shape of the organic EL material.

  Making a microlens array as shown in FIG. 14 from glass increases the cost. Therefore, a lens array made of resin is formed on the glass substrate. The manufacturing method will be described with reference to FIG. Reference numeral 1501 denotes a glass substrate, 1502 denotes an ultraviolet curable resin, 1503 denotes a lens array mold, 1504 denotes an ultraviolet lamp, and 1505 denotes an ultraviolet ray. An ultraviolet curable resin 1502 is inserted between the glass substrate 1501 and the lens array mold 1503, and the resin is cured by irradiating ultraviolet rays 1505. The lens array substrate as shown in FIG. 14 is manufactured by peeling the cured resin from the mold. By using a nanocomposite resin in which dielectric fine particles such as titanium oxide or zirconium oxide are mixed with a general ultraviolet curable resin, the refractive index of the lens portion can be increased. In order to prevent the organic EL material from deteriorating due to moisture in the air, a glass substrate is used as the substrate 1501. However, 1501 may be a resin substrate as long as the organic EL material can be protected by other methods.

  JP 2003-86353 A

  In a method of manufacturing a lens array having a conventional structure, a mold in which minute lenses are formed in an array shape is required. Such a microlens array mold is difficult to manufacture. Moreover, even if it can be manufactured, it takes a long time to manufacture and the cost increases. A lens array structure that increases the light collection efficiency of the organic EL display and is low in cost is desired.

  The display according to the present invention includes pixels arranged in an array, and an array of cylindrical lenses is arranged to face each of the pixel columns. This can improve the light collection efficiency of the display.

  Alternatively, the display of the present invention has pixels arranged in an array, has an array of first cylindrical lenses facing each of the pixel columns, and has a pixel column orthogonal to the pixel column. A second cylindrical lens array is arranged opposite to each other. This can further improve the light collection efficiency of the display.

  The lens array of the present invention is characterized by having an array of first cylindrical lenses and an array of second cylindrical lenses orthogonal to the first cylindrical lenses. This lens array can improve the light collection efficiency of the display.

  Since the display and lens array of the present invention can improve the light collection efficiency of light emitted from the organic EL material, it is possible to provide an organic EL display with high brightness and long life.

  FIG. 1 is a plan view of a display according to Embodiment 1 of the present invention.   FIG. 2 is a perspective view of the lens array substrate in Embodiment 1 of the present invention.   FIG. 3 is a cross-sectional view of the display according to Embodiment 1 of the present invention.   4 is a cross-sectional view of the display according to Embodiment 1 of the present invention in the direction perpendicular to FIG.   FIG. 5 is a plan view of a display according to Embodiment 2 of the present invention.   FIG. 6 is a perspective view of a lens array substrate in Embodiment 2 of the present invention.   FIG. 7 is a cross-sectional view of a display according to Embodiment 2 of the present invention.   FIG. 8 is a cross-sectional view of the display according to Embodiment 2 of the present invention in a direction perpendicular to FIG.   FIG. 9 is a perspective view of a lens array substrate according to Embodiment 3 of the present invention.   FIG. 10 is a sectional view of a conventional display.   FIG. 11 is a plan view of a conventional display.   FIG. 12 is a cross-sectional view of another conventional display.   FIG. 13 is a plan view of another conventional display.   FIG. 14 is a perspective view of another conventional lens array substrate.   FIG. 15 is a diagram for explaining a method of manufacturing a lens array.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1

  FIG. 1 is a plan view showing the structure of an organic EL display according to Embodiment 1 of the present invention. In FIG. 1, reference numerals 102, 103, and 104 denote red, green, and blue organic EL materials, respectively. FIG. 2 shows the cylindrical lens array substrate 105. The lens array substrate 105 is manufactured by the method shown in FIG. 15, but if the refractive index of the substrate 1501 of FIG. There is no need to specify the boundaries of. The lens array substrate 105 is placed facing the upper side of the organic EL material, and the organic EL display of Embodiment 1 is configured. In FIG. 2, the pitch of the cylindrical lens is equal to the pitch of the pixel row in FIG. The broken line in FIG. 1 is the boundary of the cylindrical lens in FIG.

  FIG. 3 is a cross-sectional view of the organic EL display of FIG. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted. Reference numeral 101 denotes a substrate, and a TFT is provided on the upper surface thereof. The TFT is not clearly shown in FIG. Reference numeral 105 denotes a cylindrical lens array substrate. Similar to FIG. 12, the light collection efficiency of the light 107 emitted from the organic EL material can be improved by the lens. In general, an organic EL material is deteriorated by moisture in the air, so it is desirable to use a glass substrate as the substrate 1501 constituting the lens array substrate 105. FIG. 3 shows a case where nitrogen or the like is sealed in a region 106 between the organic EL material and the lens array substrate 105. The lens array substrate 105 includes a general glass substrate 1501 having a refractive index of about 1.5 and a general ultraviolet curing. A resin 1502 is used.

  FIG. 4 is a cross-sectional view of the organic EL display of FIG. In FIG. 4, the same components as those in FIG. In this direction, as in FIG. 10, it cannot be expected to improve the light collection efficiency of the light 108 emitted from the organic EL material.

  In the conventional example of FIG. 14, an array of elliptic lenses is used, but in the first embodiment, an array of cylindrical lenses is used. Therefore, as described with reference to FIGS. 3 and 4, the light collection efficiency is improved in the direction in which the lens has a curvature, but the light collection efficiency cannot be expected in the direction perpendicular thereto. However, although it is difficult and costly to manufacture an elliptic lens array mold as shown in FIG. 14, the cylindrical lens array mold is relatively easy, and the light collection efficiency can be improved at a low cost.

Embodiment 2

  FIG. 5 is a plan view showing the structure of an organic EL display according to Embodiment 2 of the present invention. In FIG. 5, the same components as those in FIG. FIG. 6 shows the lens array substrate 301. The lens array substrate 301 has cylindrical lens arrays 302 and 303 that are orthogonal to each other. The directions of curvature of each of the cylindrical lens arrays 302 and 303 are opposite to each other. The lens array substrate 301 is placed on the upper side of the organic EL material to constitute the organic EL display of the second embodiment. In FIG. 6, the pitch of the cylindrical lenses in the array 302 is equal to the pitch in the long side direction of each pixel in FIG. The pitch of the cylindrical lenses in the array 303 is equal to the pitch in the short side direction of each pixel in FIG. The broken line in FIG. 5 is the boundary of the cylindrical lens in FIG. In the case of FIG. 6, the array 303 is arranged on the organic EL material side.

  FIG. 7 shows a cross-sectional view of the organic EL display of FIG. In FIG. 7, the same components as those in FIG. Reference numeral 301 denotes a lens array substrate, and reference numerals 302 and 303 denote arrays of cylindrical lenses that are orthogonal to each other. Similar to FIGS. 3 and 12, the condensing efficiency of the light 304 emitted from the organic EL material can be improved by the lens. In general, since the organic EL material is degraded by moisture in the air, it is desirable that the lens array substrate 301 is formed with the cylindrical lens arrays 302 and 303 on the glass substrate 1501. Further, nitrogen or the like is sealed in a region 106 between the organic EL material (102 to 104) and the cylindrical lens 303. More preferably, the region 106 is filled with a resin. In this case, the resin constituting the cylindrical lens arrays 302 and 303 must have a higher refractive index than the resin in the region 106.

  FIG. 8 shows a cross-sectional view of the organic EL display of FIG. 8, the same components as those in FIGS. 3 and 7 are denoted by the same reference numerals, and the description thereof is omitted. Also in this direction, the light collection efficiency of the light 305 emitted from the organic EL material can be improved as in FIGS. 3 and 12.

  In the second embodiment, by using the cylindrical lens arrays 302 and 303 orthogonal to each other, the same effect as the elliptic lens array in the conventional example of FIG. 14 can be produced, and the light collection efficiency is as high as that of the conventional example. You can improve. In order to produce an array of cylindrical lenses orthogonal to each other, the process described with reference to FIG. 15 must be used twice. That is, first, an array 302 of cylindrical lenses is formed on a glass substrate using a resin having a refractive index similar to that of glass. Subsequently, an array 303 of cylindrical lenses is formed on the cylindrical lens array 302 using a resin having a high refractive index. However, it is easier to manufacture an array mold of two types of cylindrical lenses than to manufacture an array mold of an elliptic lens, and the light collection efficiency can be improved at a lower cost than the conventional example.

Embodiment 3

  FIG. 9 shows a lens array according to Embodiment 3 of the present invention. The same components as those in FIG. In the third embodiment, a lens array substrate 301 having a cylindrical lens array 302 and a lens array substrate 304 having a cylindrical lens array 303 are bonded together with a resin having a high refractive index interposed therebetween.

  The display and the lens array of the present invention can realize a display with high light collection efficiency and can be used for a display of a portable device. The lens array of the present invention can also be used for a stereoscopic image display without glasses.

DESCRIPTION OF SYMBOLS 101 Substrate 102 Red organic EL material 103 Green organic EL material 104 Blue organic EL material 105 Cylindrical lens array substrate 106 Area between lens and organic EL material 107 Light emitted from organic EL material 108 Light emitted from organic EL material 301 Lens array substrate 302 First Cylindrical Lens Array 303 Second Cylindrical Lens Array 304 Light Emission from Organic EL Material 305 Light Emission from Organic EL Material 1001 Substrate 1002 Red Organic EL Material 1003 Green Organic EL Material 1004 Blue Organic EL Material 1005 Transparent Substrate 1006 Lens 1007 Light emitted from the organic EL material 1008 Light emitted from the organic EL material 1009 Light emitted from the organic EL material 1010 Lens array substrate 1011 Existence Light emitted by the EL material 1501 transparent substrate 1502 ultraviolet curing resin 1503 die 1504 ultraviolet lamp 1505 UV

Claims (5)

  A display having pixels arranged in an array and having an array of cylindrical lenses arranged facing each of the pixel columns.   A plurality of pixels arranged in an array; a first cylindrical lens array is disposed opposite to each of the pixel columns; and a second column opposed to each of the pixel columns orthogonal to the pixel column. A display characterized by arranging an array of cylindrical lenses.   The display according to claim 2, wherein directions of curvature of the first and second cylindrical lenses are opposite to each other.   A lens array having a first cylindrical lens array and a second cylindrical lens array orthogonal to the first cylindrical lens.   The lens array according to claim 4, wherein the first and second cylindrical lenses have opposite directions of curvature.

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