JP2004227940A - Display body, display panel, display device, and manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display panel that has a higher utilization efficiency of light by using a micro lens. <P>SOLUTION: A display panel 3 in which a micro lens 51 with an independent shape is formed using an ink jet method on nearly right above an electrode 42 in the emitting direction Z of a light-emitting element 45 is provided. Since the micro lens 51 is formed nearly right above the light-emitting element 45, the light 8 outputted from the light-emitting element 45 is swallowed into the micro lens 51 and the amount of light outputted to the outside can be made large, thereby, a display panel 3 having a high utilization efficiency and capable of displaying a bright image can be provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display and a display panel having a light emitting element such as an organic electroluminescence (organic EL).
[0002]
[Prior art]
In FIG. 11 of JP-A-2001-135377, the laminated side of the transparent plate is a plane, and the observation side opposite to the laminated side is a convex lens. One single-sided convex lens is provided for each picture element. The formed organic EL device is disclosed. In terms of picture elements, light output from the luminescent color material at a critical angle or more is also less than the critical angle at the convex lens portion and can reach the observation side, so that the extraction efficiency is improved.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2001-135377
[Problems to be solved by the invention]
In a self-luminous display panel such as the above-described display panel using an inorganic or organic EL, it is a problem that the improvement of light use efficiency, the improvement of brightness, and the reduction of power consumption are always required. In a conventional self-luminous display panel, a light-emitting element emits light in a transparent medium having a refractive index greater than 1, and its light-emitting surface is viewed through an interface between the surface of the transparent medium and air. Since light is emitted from the light emitting surface at almost all angles, a part of the light is incident on the interface between the surface of the transparent medium and air at a total reflection angle or more, and air or air is emitted from the transparent medium. This is a major factor that makes it impossible to enter the outside world and improve the light use efficiency. The display panel in which the above-described convex lens is disposed at the interface of the transparent medium is excellent in that the light use efficiency can be increased. However, if a lens is designed such that there is a thickness between the light emitting surface and the lens and light diverged through the gap is output to the outside, crosstalk between adjacent pixels becomes a problem. Therefore, the curvature of the lens cannot be increased, and the amount of light swallowed by the lens is small, so that it is impossible to use most of the light output at a critical angle or more.
[0005]
In view of the above, an object of the present invention is to provide a display body and a display panel in which a microlens is arranged on the front surface of a light emitting element and a swallowable amount of the lens can be improved. It is another object of the present invention to provide a display body and a display panel capable of further improving light use efficiency.
[0006]
[Means for Solving the Problems]
In order to solve the problem of crosstalk described above, it is sufficient that light emitted from the light emitting element does not reach a lens forming an adjacent pixel. For example, a micromirror is formed between pixels to separate light. can do. However, the number of steps for forming the micromirrors increases, and a thickness for arranging the micromirrors is required, so that the display body and the display panel become thick. Therefore, it is not an economical solution and it cannot be said that it is a preferable solution in terms of products. Therefore, in the present invention, a lens is arranged at a position on the light emitting element at least within a length of one side of the light emitting element, and a space in which light propagates to an adjacent pixel is reduced. Thereby, it is possible to prevent the occurrence of crosstalk, to allow more of the light emitted from the light emitting element to be swallowed by the lens, and to output the light to the observation side or the outside world. Therefore, the light use efficiency can be greatly improved. That is, in the display of the present invention, the light emitting element is disposed between the electrodes, and the light emitting layer emits light by the voltage applied between the electrodes, and the light emitting layer emits light from the light emitting element. And a lens layer on which at least one microlens is formed at least within a length of one side of the light emitting element.
[0007]
Therefore, with a display panel in which a plurality of display bodies of the present invention are arranged in a two-dimensional matrix, a display panel with higher contrast and capable of displaying clear color images can be provided. Further, a display device which can display a clear image can be provided by a display device including the display panel of the present invention and a driving device which drives a light-emitting element of the display panel to display an image.
[0008]
In this display body or display panel, a microlens is arranged at a position on the electrode at least within a length of one side of the light emitting element, and a thickness of a medium or a medium through which light is transmitted to an adjacent lens is limited. The purpose is to improve the brightness and freshness by reducing the crosstalk. In particular, by arranging the microlens immediately above the electrode, the space where light propagates to adjacent pixels can be eliminated or minimized. Then, by eliminating the thickness of the medium or medium through which light is transmitted to the adjacent lens, each lens, or at least the light emitting element or the lens of each pixel, has an independent shape. Therefore, a microlens array or a microlens array sheet cannot be formed, and a display panel using self-luminous elements cannot be manufactured by a method of laminating sheet materials. However, the ink jet technology used in printers in recent years can form fine dots on the order of μm. Therefore, if microlenses are formed by an inkjet method, it is possible to form independent microlenses with a shape and positional accuracy on the order of μm, and the display body and display panel of the present invention can be actually manufactured. .
[0009]
That is, in the method for manufacturing a display body of the present invention, the light emitting element is disposed between the electrodes, and the light emitting layer in which the light emitting element emits light by the voltage applied between the electrodes has the emission direction in which the light from the light emitting element is output. A microlens forming step of forming a condensing microlens by discharging a transparent resin by a microdroplet discharging device at least at a position on the electrode within a length of one side of the light emitting element. Further, in the method for manufacturing a display panel of the present invention, the light-emitting element is disposed between the electrodes, and the light-emitting element emits light by a voltage applied between the electrodes. The transparent resin is ejected by the microdroplet ejecting device to a position of at least one side of the light emitting element on the electrode in the emission direction from which the light from the light emitting element is outputted, The method includes a microlens forming step of forming a plurality of light collecting microlenses. The most suitable device for ejecting fine droplets is a device that ejects transparent resin using an ink jet method. Such a minute droplet ejecting device can use an ink ejecting device for a printer that has already established technology. it can. In addition, according to the inkjet method, a microlens having an independent shape and having almost no space for transmitting light to an adjacent microlens can be formed immediately above the electrode of the light emitting element.
[0010]
The method of forming a microlens by an inkjet method can be applied to a method of manufacturing another optical device. That is, an optical device having a microlens forming step of discharging a transparent resin by a microdroplet discharging device and forming a plurality of condensing microlenses on an emission side of an optical element layer in which optical elements are two-dimensionally arranged. Is also included in the present invention.
[0011]
By forming a microlens by an ink jet method, a convex lens or a hemispherical lens can be formed, and when a plurality of microlenses are formed, each microlens can have a substantially independent shape. Therefore, since the light from the adjacent light emitting element hardly enters the microlens, the curvature of the microlens can be made sufficiently large, and most of the light radiated forward from the light emitting element is swallowed by the lens. And output it to the outside world.
[0012]
It is also possible to mechanically cover the light emitting element with this micro lens, and by making the diameter of the micro lens larger than the diameter of the light emitting element (the length of a diagonal line in the case of a square light emitting element), the light emitting element without gaps Can be covered. On the other hand, it is also possible to arrange a plurality of smaller microlenses on the light emitting element at least within a length of one side of the light emitting element, in which case a gap may be generated between the microlenses. Therefore, it is desirable that the width of the electrode is wider than the width of the light emitting element and the light emitting element is covered with the electrode.
[0013]
Further, in the display panel according to the present invention, most of the light radiated from the light emitting element is swallowed by the convex microlenses, and the light is output in a state where the angles are substantially aligned in the emission direction. Therefore, even if a transparent cover layer is arranged in the exit direction of the lens layer, almost no light is incident on the interface of the cover layer at a critical angle or more, and the transparent cover is attached without lowering the light use efficiency. be able to. Further, by filling an inert gas having a refractive index of approximately 1 between the cover layer and the lens layer, the lens layer can be protected, and the refractive index difference between the lens and its surroundings becomes sufficient. A sufficient lens effect can be obtained.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings. The mobile phone 1 shown in FIG. 1 has a display device provided with a display panel according to the present invention. The display panel 3 on which data is displayed in the mobile phone 1 has a light-emitting layer 4 in which organic ELs, which are self-luminous elements, are arranged in a matrix, and light 8 emitted from the light-emitting layer 4 can be easily viewed by a user 9. A lens layer 5 for focusing light in the direction and a cover glass 6 are provided. In the display panel 3, the organic EL of the light-emitting layer 4 is emitted in pixel units by the driving device 2 composed of a microcomputer or the like, and data such as characters and images are transmitted to the user 9 by the light 8 output from the organic EL. Can be displayed.
[0015]
FIG. 2 shows a schematic configuration of the display panel 3. FIG. 2 is a cross-sectional view in which the display panel 3 is partially enlarged. The light emitting layer 4 of this example has a configuration in which an organic EL, which is a light emitting element 45 having a side length of x, is arranged between upper and lower electrodes 42 and 43. The light emitting element 45 emits light by the applied voltage. On the back side of the light emitting layer 4, an absorption layer 49 that also serves as a substrate and absorbs light is provided. The absorbing layer 49 absorbs external light and light emitted from the light emitting element 45 to the back side and absorbs light forward (in the emission direction). Is not reduced.
[0016]
The lens layer 5 is located within the length x of one side of the light emitting element 45 on the electrode 42 in the emission direction Z where the light 8 from the light emitting element 45 is output, and the swallowing amount of the light 8 is the highest. That is, a plurality of microlenses 51 formed right above the electrodes 42 are provided. Further, a transparent cover layer 6 is disposed in the emission direction Z of the lens layer 5, and an inert gas 7 having a refractive index of approximately 1 is filled between the cover layer 6 and the lens layer 5.
[0017]
FIG. 3 shows the light emitting layer 4 and the lens layer 5 further enlarged. A convex microlens 51 is formed directly above each light emitting element 45 with the transparent electrode 42 interposed therebetween. Therefore, as a display 46 having one light emitting element 45, each display 46 has one microlens 51, and a plurality of displays 46 are arranged in a matrix in a two-dimensional direction for display. Panel 3 is constituted. Although it is necessary to seal the organic EL, in the display panel 3 of this example, the display panel 3 is formed in a state where the light emitting elements 45 are each sealed with the transparent electrode 42 and the microlens 51.
[0018]
Each microlens 51 formed directly above the transparent electrode 42 is independent, and the light 8 emitted from a certain light emitting element 45 is swallowed by the microlens 51 corresponding to the light emitting element 45 and the adjacent light emitting element 45 emits light. It is hardly transmitted to the other microlenses 51 corresponding to the element 45. Therefore, in the display panel 3 of this example, most of the light 8 radiated from the light emitting element 45 at a wide angle can be output to the outside by changing the direction in the emission direction Z by the microlens 51. In particular, if the lens layer 5 is a flat layer, the divergent light 8w output at a wide angle becomes light having an angle equal to or greater than the critical angle at the interface with the outside, and is not output to the outside. However, by employing the lens layer 5, it is possible to make the light enter the interface 52 of the lens 51 at a critical angle or less, and output the diverging light 8w to the outside. Therefore, in the display panel 3 of the present example, the use efficiency of the light 8 output from the light emitting element 45 can be improved, and the display panel 3 is suitable for displaying a bright and clear image.
[0019]
FIG. 4 shows a display panel 60 in which a plurality of microlenses 61 are formed on a sheet 69 and stacked on the light emitting layer 4. In such a display panel 60, the distance from the light emitting element 45 to the refraction surface or interface 62 of the microlens 61 is long, and is common to the plurality of microlenses 61 in order to form the plurality of microlenses 61 into a sheet shape. Or there is a transparent media section 65 to support. Therefore, of the light output from a certain light emitting element 45, the divergent light 8w having a large emission angle may reach the interface 62 of the microlens 61 corresponding to the adjacent light emitting element 45. When the diverging light 8w is emitted to the outside from the microlens 61, crosstalk occurs between the light emitting elements 45, and the contrast and the image quality deteriorate. Therefore, the interface 62 of the microlens 61 must be designed to have a curvature such that the divergent light 8w having a large incident angle does not enter the outside. For this reason, even if the microlenses are arranged on the front surface of the light emitting element 45, the light use efficiency does not improve so much.
[0020]
On the other hand, in the display panel 3 according to the present invention shown in FIG. 3, since the plurality of micro lenses 51 are formed in an independent shape, light from the adjacent light emitting element 45 is not transmitted to the micro lens 51. . Therefore, the curvature of the interface 52 of the microlens 51 can be freely designed, and the microlens has a curvature such that it can be output to the outside including the divergent light 8w output from the light emitting element 45 at a large angle. Can be.
[0021]
FIG. 5 shows an enlarged combination of the light emitting layer 4 and the lens layer 5 of the display panel 31 according to the present invention. The above-mentioned convex lens-shaped microlens 51 has a small curvature, so that it is relatively easy to make. In addition, since the microlens 51 has a size corresponding to the light-emitting element 45 on a one-to-one basis, it is also easy to make that point. On the other hand, in the display panel according to the present invention, the curvature of the interface of the microlenses can be freely selected. In the display panel 31 of the present example, an independent microlens 53 having a substantially hemispherical interface 54 is provided. , Are provided corresponding to the respective light emitting elements 45. By employing a hemispherical micro lens 53 having a small radius of curvature and a large curvature, the divergent light 8w can be output to the outside more efficiently, and the direction of the light output to the outside is changed in the emission direction Z. Easy to align. Therefore, even when the transparent cover layer 6 is disposed on the front surface of the lens layer 5, more light can be transmitted through the transparent cover layer 6, and a brighter image can be displayed.
[0022]
FIG. 6 shows a further different display panel 32 of the present invention. FIG. 7 shows the light emitting layer 4 and the lens layer 5 of the display panel 32 extracted and further enlarged. In the display panel 32 of this example, a plurality of microlenses 55 are provided corresponding to one light emitting element 45. The individual micro lenses 55 are independent and are disposed immediately above the transparent electrode 42. Therefore, similarly to the display panels 3 and 31 described above, there is almost no possibility that crosstalk will occur due to the lens 55, and the interface 56 of the lens 55 can be designed freely. In this example, the interface 56 of the lens 55 is substantially hemispherical, and can output a wide range of divergent light 8w to the outside like the display panel 31 described above. It is a display panel that is easy to align with Z. Further, by disposing a plurality of microlenses 55 corresponding to one light emitting element 45, each microlens 55 becomes small and its height becomes low. Therefore, it is possible to provide a display panel 32 with high light use efficiency and a very thin display panel.
[0023]
On the other hand, by covering one light emitting element 45 with a plurality of microlenses 55 corresponding to one light emitting element 45, a gap is easily generated between the microlenses 55. However, in the display panel 32 of the present example, the light emitting element 45 can be sealed by the transparent electrode 42 by making the width of the emission-side electrode 42 sufficiently larger than the width of the light emitting element 45. Therefore, in the display panels 3 and 31, the microlenses 51 or 53 have a function of sealing the EL light emitting element 45, but a plurality of smaller microlenses 51 as in this example are arranged. Even in this case, the light emitting element 45 can be sufficiently sealed with the transparent electrode 42. For this reason, the display panel of the present invention can sufficiently cope with a display panel employing an organic EL as a light emitting element. Further, the mechanical strength can be sufficiently ensured by disposing the microlens 55 so as to overlap the transparent electrode 42.
[0024]
In the display panel 32 of the present example in which a plurality of micro lenses 55 are arranged corresponding to one light emitting element 45, the size of each micro lens 55 is reduced. However, if the size of the light emitting element 45 is on the order of 10 μm, the order of the shape and arrangement accuracy of the microlenses 55 is on the order of 1 μm to 10 μm, which can be sufficiently handled by the current inkjet technology. Further, since it is not necessary for each micro lens 55 to correspond to each light emitting element 45, the display panel becomes alignment-free and is easy to manufacture in that respect.
[0025]
In FIG. 8, a plurality of light emitting elements 45 are two-dimensionally arranged in a matrix, and a resin droplet 72 is ejected by an inkjet head 70 as a minute droplet ejecting device directly above the electrode 42 in the emission direction of the light emitting layer 4. The process of forming the micro lens 55 is shown. The ink-jet head 70 discharges an appropriate amount of resin having a refractive index of about 1.5 supplied from a supply pipe 75 while reciprocating on a carriage shaft 71 in the same manner as a printer, and outputs a micro-size of a desired size to a desired position. Form a lens. The shape of each microlens can be freely set by adjusting the ejection amount, the viscosity of the ejected resin, and the like.
[0026]
As shown in FIG. 6, a transparent member 6 with a step having a step deeper than the radius of the microlens 55 is formed as a cover layer on a substrate 49 in which the lens layer 5 composed of the microlens 55 is formed on the light emitting layer 4. Be attached. By mounting the cover layer 6 in an atmosphere of the inert gas 7, the inside of the cover layer 6 can be filled with the inert gas 7. Although the inside of the cover layer 6 may be filled with air, it is necessary to surely prevent the EL from deteriorating due to moisture in the air, and that the resin forming the microlenses 55 may be deteriorated by oxidation or the like. Considering this, it is preferable to employ an inert gas 7 such as nitrogen gas or argon gas.
[0027]
Further, considering the oxidation of the resin and the strength of the display panel, the inside of the cover layer 6 can be filled with a suitable transparent resin. However, the refractive index of resins is greater than gas or air, and the refractive index of many resins is greater than one. Therefore, the difference in the refractive index between the micro lens 55 and the micro lens 55 is reduced, and the lens effect of the micro lens 55 is weakened, and it becomes difficult to align the light 8 output to the outside in the emission direction Z. When covered with the cover layer 6, the surface 6 s of the cover layer 6 again becomes an interface with the outside world, so that a critical angle is generated at the interface 6 s, and light incident at a critical angle or more is output from the cover layer 6 to the outside world. Disappears. Therefore, it is desirable that the light output from the microlens 55 be directed in the emission direction Z as much as possible.
[0028]
FIG. 8 shows a manufacturing method using an ink-jet method with the display panel 32 in which a plurality of microlenses 55 are arranged on one light-emitting element 45 as an example. The display panel 3 shown in FIGS. Similarly, the microlenses 51 and 53 can be formed by the ink jet method for the lenses 31 and 31. Then, the cover 6 can be mounted in a state in which the inert gas 7 is sealed therein by the same process as described above, and a display panel having durability and high light use efficiency can be provided.
[0029]
In the embodiment of the present invention, the microlens 51, 53, or 55 is disposed immediately above the electrode 42 in the emission direction Z from which the light 8 is output, but the position at which the microlens is disposed is not limited to this. The same effect can be obtained if the position is at least within the length x of one side of the light emitting element 45 on the electrode 42 in the emission direction Z from which the light 8 is output. .
[0030]
Further, the display panels 3, 31, and 32 according to the present invention are applicable not only to the mobile phone 1 described above but also to display devices in all fields such as a car navigation system, a computer monitor, and a television. A display device capable of displaying an image and having low power consumption can be provided.
[0031]
【The invention's effect】
As described above, in the present invention, a micro-droplet ejection device such as an ink-jet method is used, and an independent microlens is placed on the electrode of the light-emitting element at least within a length of one side of the light-emitting element, particularly , Just above the electrodes. Thus, the amount of light output from the light-emitting element is swallowed by the microlenses and output to the outside world can be increased, so that a display panel with high light use efficiency and capable of displaying a bright image can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a mobile phone including a display device equipped with a display panel according to the present invention.
FIG. 2 is a cross-sectional view illustrating a schematic configuration of a display panel according to the present invention.
FIG. 3 is a cross-sectional view showing a light emitting layer and a lens layer of the display panel shown in FIG. 2 in a further enlarged manner.
FIG. 4 is a view showing a display panel provided with continuous microlenses for comparison with the display panel shown in FIG. 3;
FIG. 5 is a cross-sectional view illustrating a light emitting layer and a lens layer of a display panel different from FIG.
FIG. 6 is a cross-sectional view illustrating a schematic configuration of still another display panel.
FIG. 7 is a sectional view showing a light emitting layer and a lens layer of the display panel shown in FIG.
FIG. 8 is a diagram showing a manufacturing process of the display panel shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mobile telephone 2 Drive device 3, 31, 32 Display panel 4 Light emitting layer 5 Lens layer 51, 53, 55 Micro lens

Claims (20)

A light emitting element is disposed between the electrodes, and a light emitting layer in which the light emitting element emits light by a voltage applied between the electrodes,
A display body comprising: a lens layer having at least one microlens formed at least at a position within a length of one side of the light emitting element on the electrode in an emission direction in which light from the light emitting element is output. 2. The display according to claim 1, wherein the microlens is formed immediately above an electrode in the emission direction. The display according to claim 1, wherein the microlens is a convex lens or a hemispherical lens. The display according to claim 1, wherein a plurality of the micro lenses are stacked, and each of the micro lenses has a substantially independent shape. The display according to claim 1, wherein the diameter of the microlens is larger than the diameter of the light emitting element. 2. The display according to claim 1, wherein the width of the electrode is larger than the width of the light emitting element. A display panel comprising a plurality of the display bodies according to claim 1, wherein the display bodies are two-dimensionally arranged in a matrix. 8. The display panel according to claim 7, wherein each of the micro lenses has a substantially independent shape. The display panel according to claim 7, wherein the diameter of the microlens is larger than the diameter of the light emitting element. The display panel according to claim 7, further comprising a transparent cover layer disposed in an emission direction of the lens layer. The display panel according to claim 10, wherein an inert gas having a refractive index of approximately 1 is filled between the cover layer and the lens layer. A display device comprising: the display panel according to any one of claims 7 to 11; and a driving device that drives the light emitting element of the display panel to display an image. A light emitting element is disposed between the electrodes, of a light emitting layer in which the light emitting element emits light by a voltage applied between the electrodes, at least a light emitting element on the electrode in an emission direction in which light from the light emitting element is output. A method for manufacturing a display body, comprising a microlens forming step of forming a condensing microlens by discharging a transparent resin to a position within a length of one side by a microdroplet discharging device. 14. The method according to claim 13, wherein in the microlens forming step, a plurality of microlenses having substantially independent shapes are formed. 14. The method for manufacturing a display according to claim 13, wherein the micro-droplet discharging device discharges a transparent resin by an inkjet method. A light-emitting layer in which a light-emitting element is disposed between electrodes, and the light-emitting element emits light by a voltage applied between the electrodes, wherein the light-emitting layer includes a plurality of light-emitting elements arranged two-dimensionally in a matrix. A plurality of light-collecting micro-lenses for discharging a transparent resin by a micro-droplet discharging device onto at least a position within a length of one side of the light-emitting element on the electrode in an emission direction in which light from the element is output; A method for manufacturing a display panel, comprising a microlens forming step of forming a substrate. 17. The method of manufacturing a display panel according to claim 16, wherein, in the microlens forming step, the microlens is formed immediately above an electrode in the emission direction. Manufacturing of an optical device having a microlens forming step of forming a plurality of condensing microlenses by discharging a transparent resin with a microdroplet discharging device on an emission side of an optical element layer in which optical elements are two-dimensionally arranged. Method. 19. The method for manufacturing an optical device according to claim 18, wherein in the microlens forming step, a plurality of microlenses having substantially independent shapes are formed. 19. The method for manufacturing an optical device according to claim 18, wherein the minute droplet discharging device discharges a transparent resin by an inkjet method.

Images