JP2008205419A - Substrate for light emitting diode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a light emitting diode substrate that is transparent and transmits light at a low cost suitable for illumination and is thinned, realize manufacturing of it with a Japanese paper by allowing a substrate to be ventilative, and reduce the cost by further eliminating a resistor for current adjustment. <P>SOLUTION: A conductor is printed on a transparent film substrate through which light passes with heat transfer technology, individual lines that each form a power supply line and a large number of thin holes for ventilation and water permeability are provided in the substrate, and a small-sized surface-mounting light emitting diode is mounted, so that a thin light emitting diode through which the air, water, and light pass is manufactured at a low cost. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate for an illuminator on which a light emitting diode is mounted.

Illuminators using light emitting diodes are roughly divided into two methods. One is a mass production method for manufacturing backlights for monitors of portable devices, and the other is a method for producing a small amount of illumination.
A substrate on which a light emitting diode is mounted is used in large quantities as a backlight for a monitor of a portable device, and a flexible substrate based on polyimide is generally used as the substrate. The light-emitting diodes are surface-mounted and thin. This substrate is manufactured by a photolithography technique using an original plate, but requires special equipment such as an original plate cost of a circuit pattern and a die cost for punching the shape. Therefore, the initial cost cannot be depreciated unless the production quantity is 10,000 or more, so it is not suitable for small-volume production. Further, since the polyimide of the base material is opaque, it is difficult for light to pass through the opposite surface of the base material on which the light emitting diode is mounted.

  As a method that does not use a substrate, it has recently become common to see the illumination of Christmas as it is loaded with bullet-type light-emitting diodes and wired with electric wires. Since this method does not require a dedicated facility, it can be easily executed. However, since it takes time, the cost per product is high, and it is not suitable for downsizing and thinning.

  In recent years, the market for indoor interior lighting has grown, and new illuminators have been developed. Japanese paper with light emitting diodes has been developed. Because it is made by a manufacturing method used for illuminations such as Christmas, the portion where the light emitting diode is engraved is as thick as about 10 mm, and the electric wire portion is also raised and its presence is clearly discriminated. The positions of the wires must be aligned and productivity is poor.

  Although it is also considered to use a substrate on which a surface mount type light emitting diode is mounted with a flexible substrate, it is difficult to dry because the substrate does not allow water to pass through, and it is difficult to dry because there is no air permeability. Furthermore, even if the price is high and 10,000 or more pieces are made, the A4 size costs several thousand yen or more, and if several pieces, several tens of thousands of yen. The brightness of the light emitting diode changes depending on the flowing current and is usually used at about 10 mA, but is adjusted by the value of the resistor. Since this resistor is required, an increase in the number of parts and the number of connection points also causes an increase in cost.

  Recently, attempts have been made to form circuit patterns using thermal transfer technology. In this method, a conductive resin is formed on a transfer tape, and this is transferred to an insulating substrate with heat generated by a thermal print head, and a circuit is printed directly. Unlike the method of creating a circuit by photolithography, this method does not require an original circuit pattern, and the process of applying, exposing, developing, and stripping a photosensitive resist is not required, and a circuit can be easily and inexpensively created. Since no resist, developer, etchant or stripper is used, it is environmentally friendly. However, there is a limit to the circuit to be transferred, the conductor resistance cannot be lowered, and since a fine pattern cannot be printed, the substrate for an electronic circuit and the antenna pattern cannot be printed, so that it is not put into practical use.

Japanese Patent Application No. 2002-58337 By Kiyoshi Takagi “Until the creation of printed wiring boards” Nikkan Kogyo Shimbun Publishing, 2003 Akito Iwamoto, Hiroaki Kodera “Digital Hardcopy Technology” Kyoritsu Publishing Co., Ltd. Publishing 2000

  The problem to be solved is to realize a low-priced transparent LED substrate suitable for lighting and make it thinner, and to make the base material water-permeable and breathable and to spread it with Japanese paper. It is. Furthermore, it is to eliminate the resistor for adjusting the current.

  A circuit that forms a circuit by directly printing a conductor on a base material using thermal transfer technology, eliminating the need for an original and shortening the process, and consists of a power line with low electrical resistance and an individual line with relatively high electrical resistance. The width and length of the line are selected according to the material and film thickness of the conductor to be printed so as to have the function of a resistor.

  A circuit board produced by a thermal transfer technique is characterized in that a conductor is printed by overlapping a plurality of lines forming a part of a circuit a plurality of times, and the resistance value of the line is lowered.

  A circuit is formed by printing a conductor on a transparent substrate by a thermal transfer technique, and has a light transmission property.

  A circuit board produced by a thermal transfer technique is characterized in that a large number of holes are formed in the circuit board to provide water permeability and air permeability.

  It is a paper or a non-woven fabric characterized by having an illumination function in which a light emitting diode substrate is inserted into a core.

  In the circuit board produced by the thermal transfer technique, an arbitrary line forming a part of the circuit is visually dedesigned.

By printing a conductor directly on a transparent base material with the thermal transfer technology of the present invention, it is possible to produce a circuit pattern master without using a punching die without going through a photolithography process. It is environmentally friendly because it is greatly reduced and does not use solvents such as developer, etchant or stripper. There is an advantage that a resistor can also be formed by a conductor printed on the substrate, and the cost can be reduced.
A large number of holes for air and water to pass through are formed in the substrate, so it can be dried by sandwiching it with Japanese paper using a paper-making technique, and a small light-emitting diode is mounted to achieve illumination of thin Japanese paper of about 1 mm. be able to. Since the base material is transparent, there is also an advantage that light is emitted from the front and back of the Japanese paper.

  Printed conductors on a transparent film substrate that transmits light by thermal transfer technology, individual lines that form power lines and resistors, and small surface mounts with numerous fine holes on the board for ventilation and water permeability It is possible to produce a low-cost thin LED substrate that allows air, water, and light to pass through. The circuit line is designed to be suitable for crafts.

  FIG. 1 is a view of a light emitting diode substrate according to one embodiment of the present invention as viewed from the surface on which components of the light emitting diode substrate are mounted. FIG. FIG. 3 is a view seen from a surface on which components are mounted when a large number of holes are provided in the light emitting diode substrate of FIG. FIG. 4 is a cross-sectional view of a Japanese paper with a lighting function in which a light emitting diode substrate is inserted into a core.

  The light emitting diode substrate of FIG. 1 uses a transparent film as a base material 1, prints a conductor on the surface, and thermally transfers a negative electrode (positive electrode) power line 2, a positive electrode (negative electrode) power line 3, and resistors 4 and 5. Printed with technology. In this example, a PET film was used as the transparent film. The circuit pattern was drawn with personal computer software and illustrator (trade name) and printed with a dedicated printer. Using a ribbon in which copper having a thickness of 0.1 μm was deposited on a base tape by a sputtering apparatus, heat was applied by a thermal print head, and the copper deposited on the base tape was transferred to the substrate 1 and printed.

  Printed copper sheet resistance (square surface resistance value) is about 1Ω, the sheet resistance of a general board conductor is much larger than about 1mΩ, and the area of the power line must be increased . Since the board for illumination is not so high in mounting density, the area of the power supply line can be easily obtained, so there is no problem. The substrate size in this example was a postcard size of 105 mm × 148 mm, the dimensions of the power supply lines 2 and 3 were 100 mm × 30 mm, and the resistance value was suppressed to a little over 3Ω.

  A resistor can be created by utilizing the large sheet resistance. In this embodiment, the design is such that 10 mA and 20 mA flow through the two light emitting diodes, respectively. When DC 5v is applied to the light emitting diode and the resistor connected in series, approximately 3v and 2v are applied to both ends of the light emitting diode and the resistor, respectively. Therefore, if the resistor is 200Ω, 10 mA can be passed. The resistor 4 of this embodiment is 2 mm in width and 200 mm in length, a 100Ω resistor is made, and 20 mA is passed through the light emitting diode. Resistor 5 was made to have a width of 2 mm and a length of 400 mm, thereby creating a 200Ω resistor and allowing 10 mA to flow through the light emitting diode.

  When the light emitting diodes 6 and 7 are mounted between the resistors 4 and 5 and the negative (positive) power supply line 3 and a DC voltage 5v is applied to the power supply lines 2 and 3, currents of 20 mA and 10 mA flow through the light emitting diodes to emit light. The electrode lines 2 and 3 have a resistance of more than 3Ω, but it is more than 3% compared to 100Ω of the resistor 4, and the difference in luminance due to such an error cannot be discriminated at all by human eyes. There is no problem at all.

  FIG. 2 shows an example in which the power supply line has two layers and the resistance value is lowered. The circuit pattern is exactly the same as in FIG. 1, but only the power line is printed twice. Two circuit patterns were prepared with an illustrator. The first sheet is exactly the same as FIG. 1, and the second sheet is a circuit pattern of only the negative electrode (positive electrode) power line 21 and the positive electrode (negative electrode) power line 22 of FIG. First, the former pattern was printed, and then the latter pattern was printed. The power line was made up of two layers, and the resistance value was about half, which was a little less than 2Ω. In this way, the resistance value can be lowered by printing the conductor a plurality of times.

  If a light emitting diode is mounted on the substrate of this embodiment and attached to glass or the like, thin illumination can be realized. Moreover, if it is rolled into a cylindrical shape and fitted in a glass cup or the like, round illumination can be achieved and light is illuminated through the transparent substrate.

  FIG. 3 shows an embodiment of a substrate of a light emitting diode provided with a large number of fine holes, in which holes are processed in the substrate of FIG. In this example, the hole was formed by punching. The hole diameter is 1 mm and the pitch is 2 mm. Therefore, since a hole of 0.785 square millimeters is opened in 4 square millimeters, the resistance value increases by about 20%. Therefore, if this amount is corrected, a predetermined resistance value can be obtained.

First, the paper is rolled up until the thickness becomes half the thickness of the target paper, and the base layer 1 is formed. A substrate on which the light-emitting diodes 6 are mounted on the substrate on which many holes are formed on the rolled paper. Then, the cover layer 2 is formed by rolling the paper to a desired thickness. At this time, a large number of holes formed in the substrate allow water to pass through, thereby enabling papermaking. In the case of this embodiment, a cover layer 43 for protecting the conductor is provided in order to reduce oxidation due to water and drying heat in the papermaking process. A silicon resin was coated as a material for the cover layer 43. The same silicon resin was used as the sealing resin for sealing the light emitting diode 6. These protections are used to increase quality.
In addition, it is possible to sandwich a light-emitting diode substrate between Japanese paper by sandwiching two sheets of paper in advance and sandwiching a substrate with a large number of holes between them. However, since the numerous holes are breathable, they can be dried. Is possible. In this way, the light emitting diode substrate can be sandwiched between Japanese paper.
In addition, the nonwoven fabric which can be manufactured by the method similar to papermaking can also be utilized.

  FIG. 5 shows an example of designing the power supply line of FIG. When the light emitting diode substrate of the present invention is attached to glass for illumination, a circuit pattern can be seen, and sometimes this pattern can appear insignificant. Therefore, a circuit pattern is designed as a countermeasure. The function of the circuit line created by the thermal transfer technology is added to the electrical function. This makes it more suitable as a craft.

Conceptual diagram viewed from a surface on which a component showing the structure of a light emitting diode substrate is mounted (Example 1) Conceptual diagram viewed from the surface on which a component showing the structure of a light emitting diode substrate having two layers of power supply lines is mounted (Example 2) Conceptual diagram viewed from the surface on which a component is printed that shows the structure of a board on which a circuit is printed by thermal transfer technology and a large number of holes are formed (Example 3) Conceptual sectional view showing a structure of illumination in which a light emitting diode substrate is sandwiched between Japanese papers (Example 4) Conceptual diagram viewed from the surface on which the components showing the structure of the substrate for light emitting diodes with the power line designed (Example 5)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Negative electrode (positive electrode) power supply line 3 Positive electrode (negative electrode) power supply line 4,5 Resistor 6,7 Light emitting diode 21 Second layer negative electrode (positive electrode) power supply line 22 Second layer positive electrode (negative electrode) power supply line 31 Hole 41 Base layer (Japanese paper)
42 Cover layer (Japanese paper)
43 Cover layer (light emitting diode substrate)
44 Sealing resin 51 Designed negative electrode (positive electrode) power line 52 Designed positive electrode (negative electrode) power line

Claims (6)

  A circuit that forms a circuit by directly printing a conductor on a base material using thermal transfer technology, eliminating the need for an original and shortening the process, and consists of a power line with low electrical resistance and an individual line with relatively high electrical resistance. A light-emitting diode substrate, wherein the width and length of a line are selected according to the material and film thickness of a conductor to be printed so as to have a function of a resistor.   A substrate for a light-emitting diode, characterized in that, in a circuit board produced by a thermal transfer technique, a conductor is printed by overlapping a plurality of lines forming a part of a circuit a plurality of times, and the resistance value of the line is lowered.   A substrate for a light-emitting diode, characterized in that a circuit is formed by printing a conductor on a transparent base material by a thermal transfer technique and has a light transmission property.   A substrate for a light-emitting diode, characterized in that in a circuit board produced by a thermal transfer technique, a large number of holes are formed in the circuit board to provide water permeability and air permeability.   A paper or non-woven fabric having an illumination function in which the light-emitting diode substrate according to claim 4 is inserted into a core.   A light-emitting diode substrate characterized in that an arbitrary line forming part of a circuit is visually dedesigned in a circuit substrate produced by a thermal transfer technique.

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