JP2004184754A - Method for manufacturing flat panel display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a flat panel display that can exhibit superior light diffusion through simple manufacturing processes and miniaturize a light emitting element by excellently dispersing light emitted by a spot light source. <P>SOLUTION: This method includes the processes of: arraying LED elements 12 in matrix on a substrate 11; forming an interlayer dielectric 14 on the substrate and LED elements; forming a wiring layer 16 which is electrically connected to the LED elements on the interlayer dielectric; forming a film of a light diffusion layer 17 by coating the interlayer dielectric and wiring layer with a cardo type polymer; and holding the substrate including the light diffusion layer before setting in environment of pressure lower than the atmospheric pressure in the deposition process. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
[0002]
The present invention relates to a method for manufacturing a flat panel display in which so-called point light sources are arranged in a matrix, such as a light emitting diode display, a plasma display, a liquid crystal display, and an organic electroluminescence display.
[Prior art]
This type of flat panel display is expected to realize a high-performance and compact display. In particular, in an LED display having excellent luminous efficiency, a high-brightness, high-contrast display can be realized by two-dimensionally arranging red, green, and blue packaged LEDs in an array. And a large-screen full-color display in the field.
[0003]
[Problems to be solved by the invention]
By the way, if a point light source with high luminous efficiency is used, the light source can be miniaturized.However, if the area of the light emitting area is made small in this way, the light source looks like a point when the display is viewed from a close distance. However, there is a problem that the image is rather coarsened.
[0004]
For this reason, it has been studied to appropriately diffuse light emitted from a point light source. For example, in Patent Literature 1, a light-absorbing binder in which fine light-transmitting beads are dispersed is applied to a light-transmitting sheet such as glass or resin, and dried to diffuse light emitted from a display. It is disclosed to obtain a light-diffusing sheet.
[0005]
However, the light diffusion sheet obtained according to Patent Literature 1 requires a large number of manufacturing steps, and it is difficult to control the steps for uniformly dispersing fine beads.
[0006]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-298205
[Means for Solving the Problems]
An object of the present invention is to provide a method for manufacturing a flat panel display that can exhibit excellent light diffusing properties in a simple manufacturing process and can appropriately miniaturize a light emitting element by appropriately dispersing light emitted from a point light source. Aim.
(1) According to the present invention, in a method for manufacturing a flat panel display in which dot light emitting elements are provided in a matrix on a substrate, pressure expansion and contraction are performed so as to directly or indirectly cover the point light emitting elements. A step of applying a conductive resin to form a light diffusion layer, and a step of holding the substrate including the light diffusion layer before curing in a low-pressure or high-pressure environment with respect to the pressure of the film formation step. A method for manufacturing a flat panel display is provided.
[0008]
In the present invention, a pressure-expandable resin is applied so as to directly or indirectly cover the point light emitting element, and the substrate is held under a low-pressure environment or a high-pressure environment before the resin is cured. Thereby, fine irregularities are formed on the surface of the obtained light diffusion layer. Then, the light emitted from the point-like light emitting element is appropriately diffused by the minute unevenness, and the image does not appear coarse even if the light emitting element is miniaturized. In particular, fine irregularities are formed only by forming a light diffusion layer and holding it under a reduced pressure environment or an increased pressure environment, so that the manufacturing process can be significantly simplified.
[0009]
In the present invention, the pressure swellable resin constituting the light diffusion layer may be applied so as to directly cover the point light emitting element, or may be applied indirectly through another layer. . In short, the light diffusion layer of the present invention may be formed at a position where emitted light passes through the light diffusion layer.
[0010]
In the present invention, the pressure at which the substrate including the light diffusion layer before curing is held may be lower or higher than the pressure in the step of forming the pressure-expandable resin. If pressure fluctuations occur with respect to the atmospheric pressure at the time of application, irregularities will be formed on the surface of the light diffusion layer.
[0011]
The pressure swellable resin used in the present invention is a resin having the property of expanding or contracting in response to pressure fluctuation, and is not particularly limited, and examples thereof include a cardo type polymer. As shown in FIG. 5, a cardo type polymer is a polymer having a structure in which a main chain M and a bulky side chain S are connected by one element (this corresponds to a cardo (in Latin, a hinge)). It is a generic name. When a pressure-swelling resin represented by such a cardo-type polymer is held in a low-pressure environment or a high-pressure environment, fine irregularities appear on the surface, and this is cured, or held in a low-pressure environment or a high-pressure environment. By performing the curing, a light diffusion layer having fine irregularities on the surface can be obtained.
[0012]
When the pressure-swellable resin is maintained in a low-pressure or high-pressure environment, the pressure difference and the arrival time are important. However, depending on the characteristics of the pressure-swellable resin used and the surface roughness of the target light diffusion layer, these pressure differences can be reduced. It is preferable to appropriately determine the pressure difference and the arrival time. In a preferred embodiment of the present invention, the pressure-swelling resin is applied under atmospheric pressure, and the pressure is reduced from atmospheric pressure to at least 1 × 10 ⁻³ Pa at a pumping speed within 2 minutes. Thereby, fine unevenness having a surface roughness of 1 μm to 10 μm is formed on the surface of the light diffusion layer.
[0013]
The flat panel display according to the manufacturing method of the present invention can be applied to any flat panel display such as a light emitting diode display, a plasma display, a liquid crystal display, and an organic electroluminescence display, which are so-called point light sources arranged in a matrix. Can be.
(2) In particular, in the case of a point-shaped light emitting element having excellent luminous efficiency such as a light emitting diode display, a problem that an image looks coarse when the light emitting element is miniaturized becomes remarkable. Is preferred.
[0014]
That is, as an embodiment of the present invention, a step of arranging point light emitting elements on a substrate in a matrix, a step of forming an interlayer insulating layer on the substrate and the point light emitting elements, Forming a wiring layer electrically connected to the point light emitting element; applying a pressure swellable resin on the interlayer insulating layer and the wiring layer to form a light diffusion layer; Holding the substrate including the light diffusion layer before curing in a low or high pressure environment with respect to the atmospheric pressure in the film forming step.
[0015]
Further, as another embodiment of the present invention, a step of arranging the point-like light emitting elements in a matrix on a substrate, and applying an insulating pressure-expandable resin on the substrate and the point-like light emitting elements. Forming a light diffusion layer; forming a wiring layer electrically connected to the point light emitting element on the light diffusion layer; and forming the substrate including the light diffusion layer before curing by the film formation step. And a step of maintaining the environment in a low or high pressure environment with respect to the atmospheric pressure.
[0016]
In the manufacturing method of the flat panel display according to these embodiments, in the former manufacturing method, a light diffusion layer made of a pressure-expandable resin is formed on the wiring layer and the interlayer insulating layer, whereas in the latter manufacturing method, Since the interlayer insulating layer for insulating the point light emitting element and the wiring layer is a light diffusion layer, the latter manufacturing method has a shorter manufacturing process.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
1st Embodiment FIG. 1 is a process diagram showing a method of manufacturing a flat panel display according to a first embodiment of the present invention, and FIG. 2 shows a method of manufacturing a flat panel display according to a first embodiment of the present invention. It is a panel sectional view showing. In the present embodiment, the present invention will be described with reference to an LED color display using red (R), blue (B), and green (G) light emitting diodes (hereinafter, also referred to as LEDs) as point light emitting elements.
[0019]
One unit of the LED color display 1 according to this example is shown in FIG. 2 (F). An LED 12 of one of three colors, red, blue and green, is provided on a substrate 11 made of glass or the like. The drive circuit element 13 for driving is mounted using an adhesive or the like. The LEDs 12 of the three colors are arranged vertically and horizontally in this order, and the LEDs 12 are arranged in a matrix on the entire substrate 11. A region where one set of red, blue and green LEDs 12 and their driving circuit elements 13 are mounted constitutes one pixel of the display 1.
[0020]
On the surface of the substrate 11 on which the LED 12 and the drive circuit element 13 are mounted, an interlayer insulating layer 14 for ensuring insulation between the LED 12 and the drive circuit element 13 is formed. The interlayer insulating layer 14 can be made of an insulating polymer or the like.
[0021]
A wiring layer 16 is formed on the surface of the interlayer insulating layer 14 via a connection hole (via hole) 15 for making an electrical connection with a contact of the LED 12 and a contact of the drive circuit element 13.
[0022]
The connection hole 15 is formed by forming a small hole in the interlayer insulating layer 14 using a laser beam or the like, or by forming a small hole by a technique such as patterning, and then filling the wiring layer 16 with a conductor at the same time.
[0023]
The wiring layer 16 is formed with a wiring pattern for supplying power to the LED 12 and the drive circuit element 13 and transmitting a control signal, and is formed by sputtering or patterning a conductor.
[0024]
In particular, in the display 1 of the present example, a light diffusion layer 17 made of a cardo-type polymer is formed on the surfaces of the interlayer insulating layer 14 and the wiring layer 16. The surface of the light diffusion layer 17 has fine irregularities with a surface roughness of 1 μm to 10 μm by a manufacturing method according to the present invention described later.
[0025]
Next, a method for manufacturing the LED color display 1 of the present example will be described.
First, as shown in FIG. 2A, the LEDs 12 and the drive circuit elements 13 are mounted on the upper surface of the glass substrate 11 in a matrix using an adhesive or the like (LED mounting step 101). Next, as shown in FIG. 2B, an insulating resin is applied on the upper surface of the substrate 11 on which the LED 12 and the drive circuit element 13 are mounted so as to cover the LED 12 and the drive circuit element 13 and is cured. The interlayer insulating layer 14 is formed (interlayer insulating layer forming step 102).
[0026]
Next, as shown in FIG. 3C, a connection hole 15 is opened at a predetermined position of the interlayer insulating layer 14 using a laser beam to expose contacts of the LED 12 and the drive circuit element 13 (connection hole forming step 103). .
[0027]
Next, as shown in FIG. 3D, a metal is deposited on a predetermined position (a position corresponding to a wiring pattern) on the surface of the interlayer insulating layer 14 and the connection hole 15 by sputtering, and a predetermined wiring pattern is formed by patterning. (Wiring layer forming step 104). Thereby, the connection hole 15 is filled with the metal and the wiring layer 16 is formed, and the LED 12 and the drive circuit element 13 are electrically connected to the wiring layer 16.
[0028]
Next, as shown in FIG. 5E, a cardo type polymer is applied by spin coating or the like on the upper surface of the interlayer insulating layer 14 on which the wiring layer 16 is formed, and a light diffusion layer 17 is formed (light diffusion layer 17). Film forming step 105). In this state, the cardo type polymer is uncured. The above steps are performed under an atmospheric pressure environment.
[0029]
After the light diffusion layer forming step 105 is completed, the cardo type polymer constituting the light diffusion layer 17 is cured (light diffusion layer curing step 106). In the curing step, when the cardo type polymer used is a thermosetting polymer, the amount of heat (temperature × time) required for curing the polymer is given, and when the cardo type polymer used is a photocurable polymer. Gives the amount of light (intensity x time) needed to cure the polymer.
[0030]
Finally, when the light diffusion layer 17 is cured, the substrate 11 in the state shown in FIG. 7E is put into a vacuum device (not shown), and the pumping speed within 2 minutes from atmospheric pressure to at least 1 × 10 ⁻³ Pa. To maintain this state for a predetermined time (reduced pressure holding step 107). Due to this rapid decompression, the surface of the uncured light diffusion layer 17 shrinks, as shown in FIG.
[0031]
In the display 1 obtained by the above steps, fine irregularities of about 1 μm to 10 μm are formed on the surface of the light diffusion layer 17, so that the emitted light emitted from the LED 12 The light is diffused by the fine unevenness, and as a result, the area where the point light source of the LED 12 is visually recognized becomes large. Therefore, when the LED is miniaturized, the conventional problem that the image looks coarse even when the display is viewed close to the display is solved.
[0032]
The inventor manufactured an LED display manufactured in the above process and a conventional LED display without forming the light diffusion layer 17 and visually evaluated the visual recognition state of the light source. No defects such as coarse images were observed at all, which was extremely good as compared with the conventional LED display produced at the same time.
[0033]
Second Embodiment FIG. 3 is a process diagram showing a method for manufacturing a flat panel display according to a second embodiment of the present invention, and FIG. 4 is a flowchart showing a method for manufacturing a flat panel display according to the second embodiment of the present invention. It is a panel sectional view showing. In the present embodiment, the present invention will be described with reference to an LED color display using red (R), blue (B), and green (G) light emitting diodes (hereinafter, also referred to as LEDs) as point light emitting elements.
[0034]
One unit of the LED color display 1 according to the present embodiment is shown in FIG. 4 (E). An LED 12 of one of three colors of red, blue and green is provided on a substrate 11 made of glass or the like. The drive circuit element 13 for driving is mounted using an adhesive or the like. The LEDs 12 of the three colors are arranged vertically and horizontally in this order, and the LEDs 12 are arranged in a matrix on the entire substrate 11. A region where one set of red, blue and green LEDs 12 and their driving circuit elements 13 are mounted constitutes one pixel of the display 1.
[0035]
On the surface of the substrate 11 on which the LED 12 and the drive circuit element 13 are mounted, a light diffusion layer 17 having an insulating property is formed in order to secure insulation from the LED 12 and the drive circuit element 13. The light diffusion layer 17 has an insulating property and can be made of a polymer having a pressure swelling property as described later. In this example, it is made of a cardo type polymer. The surface of the light diffusion layer 17 has fine irregularities with a surface roughness of 1 μm to 10 μm by a manufacturing method according to the present invention described later.
[0036]
A wiring layer 16 is formed on the surface of the light diffusion layer 17 via a connection hole (via hole) 15 for making electrical connection with the contact of the LED 12 and the contact of the drive circuit element 13.
[0037]
The connection hole 15 is formed by forming a small hole in the light diffusion layer 17 by using a laser beam or the like, or by forming a small hole by a method such as patterning, and then filling the conductor at the same time when the wiring layer 16 is formed.
[0038]
The wiring layer 16 is formed with a wiring pattern for supplying power to the LED 12 and the drive circuit element 13 and transmitting a control signal, and is formed by sputtering or patterning a conductor.
[0039]
Next, a method for manufacturing the LED color display 1 of the present example will be described.
First, as shown in FIG. 4A, the LEDs 12 and the drive circuit elements 13 are mounted on the upper surface of the glass substrate 11 in a matrix using an adhesive or the like (LED mounting step 201). Next, a cardo type polymer is applied by spin coating or the like on the upper surface of the substrate 11 on which the LED 12 and the driving circuit element 13 are mounted as shown in FIG. The layer 17 is formed (light diffusion layer film formation 202). In this state, the cardo type polymer is uncured. The above steps are performed under an atmospheric pressure environment.
[0040]
Next, as shown in FIG. 4C, a connection hole 15 is opened at a predetermined position of the light diffusion layer 17 using a laser beam, and the contact between the LED 12 and the drive circuit element 13 is exposed (connection hole forming step 203). .
[0041]
Next, as shown in FIG. 3D, a metal is deposited on a predetermined position (a position corresponding to a wiring pattern) on the surface of the light diffusion layer 17 and the connection hole 15 by sputtering, and a predetermined wiring pattern is formed by patterning. (Wiring layer forming step 204). Thereby, the connection hole 15 is filled with the metal and the wiring layer 16 is formed, and the LED 12 and the drive circuit element 13 are electrically connected to the wiring layer 16.
[0042]
After the completion of the wiring layer forming step 204, the cardo type polymer constituting the light diffusion layer 17 is cured (light diffusion layer curing step 205). In the curing step, when the cardo type polymer used is a thermosetting polymer, the amount of heat (temperature × time) required for curing the polymer is given, and when the cardo type polymer used is a photocurable polymer. Gives the amount of light (intensity x time) needed to cure the polymer.
[0043]
Finally, when the light diffusion layer 17 is cured, the substrate 11 in the state shown in FIG. 4D is put into a vacuum device (not shown), and the pumping speed within 2 minutes from atmospheric pressure to at least 1 × 10 ⁻³ Pa. , And this state is maintained for a predetermined time (reduced pressure holding step 206). Due to this rapid decompression, the surface of the uncured light diffusion layer 17 contracts as shown in FIG.
[0044]
In the display 1 obtained by the above steps, since fine irregularities of about 1 μm to 10 μm are formed on the surface of the light diffusion layer 17, the emitted light emitted from the LED 12 The light is diffused by the fine unevenness, and as a result, the area where the point light source of the LED 12 is visually recognized becomes large. Therefore, when the LED is miniaturized, the conventional problem that an image looks coarse even when the display is viewed close to the display is solved.
[0045]
Further, in the manufacturing method of this example, since the step of forming an interlayer insulating layer can be omitted as compared with the above-described first embodiment, an LED flat panel display can be obtained with a much simpler manufacturing process.
[0046]
The present inventor manufactured the LED display manufactured in the above process and a conventional LED display without forming the light diffusion layer 17, and visually evaluated the visual recognition state of the light source. No defects such as coarse images were observed at all, which was extremely good as compared with the conventional LED display produced at the same time.
[0047]
The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[0048]
【The invention's effect】
As described above, according to the present invention, a flat panel display capable of exhibiting excellent light diffusing properties in a simple manufacturing process and allowing a light emitting element to be miniaturized by suitably dispersing light emitted from a point light source. A manufacturing method can be provided.
[Brief description of the drawings]
FIG. 1 is a process chart showing a method for manufacturing a flat panel display according to a first embodiment of the present invention.
FIG. 2 is a panel cross-sectional view illustrating the method of manufacturing the flat panel display according to the first embodiment of the present invention.
FIG. 3 is a process chart showing a method of manufacturing a flat panel display according to a second embodiment of the present invention.
FIG. 4 is a panel cross-sectional view illustrating a method of manufacturing a flat panel display according to a second embodiment of the present invention.
FIG. 5 is a schematic diagram showing a molecular structure of a cardo-type polymer according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Flat panel display 11 ... Substrate 12 ... LED element (point light emitting element)
DESCRIPTION OF SYMBOLS 13 ... Drive circuit element 14 ... Interlayer insulating layer 15 ... Connection hole 16 ... Wiring layer 17 ... Light diffusion layer

Claims (6)

In a method of manufacturing a flat panel display in which dot light emitting elements are provided in a matrix on a substrate,
A step of applying a pressure-expandable resin to directly or indirectly cover the point-like light emitting element to form a light diffusion layer,
Holding the substrate including the light diffusion layer before curing in a low or high pressure environment with respect to the atmospheric pressure in the film forming step. 2. The method according to claim 1, wherein the pressure swellable resin is a cardo type polymer. Arranging the point light emitting elements in a matrix on a substrate, forming an interlayer insulating layer on the substrate and the point light emitting elements, and electrically connecting the point light emitting elements on the interlayer insulating layer. A step of forming a wiring layer to be connected; a step of applying a pressure-expandable resin on the interlayer insulating layer and the wiring layer to form a light diffusion layer; and a substrate including the light diffusion layer before curing. And a step of maintaining the pressure in an environment of a low pressure or a high pressure with respect to the atmospheric pressure of the film forming step. Arranging point light emitting elements in a matrix on a substrate, forming a light diffusing layer by applying an insulating pressure swellable resin on the substrate and the point light emitting elements, Forming a wiring layer electrically connected to the point light emitting element on the diffusion layer; and subjecting the substrate including the light diffusion layer before curing to a low pressure or high pressure environment with respect to the pressure of the film forming step. And a step of holding the flat panel display. The method according to claim 4, wherein the pressure swellable resin is a cardo-type polymer. The method for manufacturing a flat panel display according to claim 4, wherein the point light emitting element is a light emitting diode.

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