KR102091912B1 - Flexible printed circuit board and display system including the same - Google Patents

Abstract

A transparent flexible printed circuit board and a display system comprising the same are disclosed. The transparent flexible printed circuit board according to an embodiment includes a transparent substrate, a first adhesive layer formed on at least one of upper and lower portions of the transparent substrate, and a metal layer formed by patterning on the upper portion of the first adhesive layer And, a second adhesive layer formed on at least one of the upper portion of the region of the metal layer is not attached to the LED element and the first adhesive layer, and is formed on the transparent substrate is formed on both sides of the transparent substrate It includes a via hole connecting the metal layer.

Description

Transparent flexible printed circuit board and display system including the same {FLEXIBLE PRINTED CIRCUIT BOARD AND DISPLAY SYSTEM INCLUDING THE SAME}

The following embodiments relate to a transparent flexible printed circuit board and a display system including the same.

Recently, the use range of LED (light emitting diode) devices has been expanded. For example, recently, LED elements are used in various fields such as indoor and outdoor lighting, as well as automobile headlights and displays.

LED devices having advantages such as processing speed and power consumption have been recently used in the transparent display field.

The printed circuit board used in the transparent display field must have excellent transparency. For example, a printed circuit board used in the transparent display field may be manufactured by mounting a LED device on a substrate using transparent polyethylene naphthalate (PEN).

However, PEN increases the production price of LED display modules due to the high cost. PEN has problems such as laser perforation, air bubbles and poor permeability.

Accordingly, recently, a printed circuit board having transparency and price competitiveness is required.

Embodiments can provide a technique for reducing the production cost for a printed circuit board by providing a transparent flexible printed circuit board having a double-sided metal layer and via holes formed in a heat-resistant PET material.

Embodiments can provide a technology that increases the likelihood of entering the market by providing a transparent flexible printed circuit board with low production cost.

The flexible printed circuit board according to an embodiment includes a transparent substrate, a first adhesive layer formed on at least one of the upper and lower portions of the transparent substrate, and a metal layer formed by patterning on the upper portion of the first adhesive layer. , A second adhesive layer formed on at least one of an upper portion of a region in which the LED element is not attached and an upper portion of the first adhesive layer in the region of the metal layer, and a metal layer formed on both sides of the transparent substrate on the transparent substrate It includes a via hole connecting.

The flexible printed circuit board according to an embodiment includes a conductive layer formed on an area of the metal layer to which the LED element is attached, and a solder for surface mounting the LED element on at least one of the metal layer and the conductive layer. It may further include.

The transparent substrate may be flexible and may be heat-resistant polyethylene tereohthalate (PET).

The first adhesive layer may be transparent.

The metal layer may be at least one of a copper layer and a nickel layer.

The second adhesive layer is transparent, and can prevent corrosion and physical damage of the metal layer.

The conductive layer may be at least one of a Ni layer and an Au layer.

The solder may be for surface mounting technology (SMT).

The display system according to an embodiment includes an LED element, a flexible printed circuit board surface-mounting the LED element, and a driving device controlling at least one of the LED element and the flexible printed circuit board.

The flexible printed circuit board includes a transparent substrate, a first adhesive layer formed on at least one of the upper and lower portions of the transparent substrate, a metal layer formed by patterning on the upper portion of the first adhesive layer, and the metal layer. A via hole connecting a second adhesive layer formed on at least one of an upper portion of the region to which the LED element is not attached and an upper portion of the first adhesive layer, and a metal layer formed on both sides of the transparent substrate on the transparent substrate. It may include.

The flexible printed circuit board further includes a conductive layer formed on an area of the metal layer to which the LED element is attached, and a solder for surface mounting the LED element on at least one of the metal layer and the conductive layer. You can.

The transparent substrate may be flexible and may be heat-resistant polyethylene tereohthalate (PET).

The first adhesive layer may be transparent.

The metal layer may be at least one of a copper layer and a nickel layer.

The second adhesive layer is transparent, and can prevent corrosion and physical damage of the metal layer.

The conductive layer may be at least one of a Ni layer and an Au layer.

The solder may be for surface mounting technology (SMT).

1 is a schematic cross-sectional structural diagram of a flexible printed circuit board according to an embodiment.
FIG. 2 shows an example for explaining the process of the flexible printed circuit board shown in FIG. 1.
3 shows an example for explaining a metal layer pattern of the flexible printed circuit board shown in FIG. 1.
4 is an enlarged view of area A of FIG. 1.
FIG. 5 shows another example for explaining the process of the flexible printed circuit board shown in FIG. 1.
6 shows an example for explaining the solder pattern of the flexible printed circuit board shown in FIG. 1.
7 is a schematic block diagram of a display system according to an embodiment.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are exemplified only for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention These can be implemented in various forms and are not limited to the embodiments described herein.

Embodiments according to the concept of the present invention can be applied to various changes and can have various forms, so that the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosure forms, and includes modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various components, but the components should not be limited by the terms. The above terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be referred to as the second component, Similarly, the second component may also be referred to as the first component.

When an element is said to be “connected” or “connected” to another component, it is understood that other components may be directly connected to or connected to other components, but other components may exist in the middle. It should be. On the other hand, when a component is said to be “directly connected” or “directly connected” to another component, it should be understood that no other component exists in the middle. Expressions describing the relationship between the components, for example, “between” and “just between” or “adjacent to” and “directly neighboring to” should be interpreted similarly.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the term “include” or “have” is intended to designate the presence of a feature, number, step, action, component, part, or combination thereof as described, one or more other features or numbers, It should be understood that the existence or addition possibilities of steps, actions, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined herein. Does not.

A module in the present specification may mean hardware capable of performing functions and operations according to each name described in the present specification, or computer program code capable of performing specific functions and operations. Or, it may mean an electronic recording medium on which computer program code capable of performing a specific function and operation is mounted, for example, a processor or a microprocessor.

In other words, the module may mean a functional and / or structural combination of hardware for performing the technical idea of the present invention and / or software for driving the hardware.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. The same reference numerals in each drawing denote the same members.

1 is a schematic cross-sectional structural diagram of a flexible printed circuit board according to an embodiment.

Referring to FIG. 1, a flexible printed circuit board (100) includes a transparent substrate (110), a first adhesive layer (120), a metal layer (130), and a second It includes an adhesive layer (second adhesive layer; p 140) and a via hole (150).

The transparent substrate 110 may be made of flexible and heat-resistant polyethylene tereohthalate (PET). For example, the transparent substrate 110 may be 200 μm thick.

Heat-resistant PET may not melt to about 180 ° C. Heat-resistant PET can be applied with SMT (surface mounting technology) for mounting electronic components.

Heat-resistant PET may be a very inexpensive material used in manufacturing antennas for mobile phones. The substrate made of heat-resistant PET may have a lower production cost because the material cost is cheaper than the substrate made of polyethylene naphthalate (PEN). The substrate made of heat-resistant PET may have higher transparency than the substrate made of polyimide (PI), and the production cost may be low due to inexpensive material cost.

The first adhesive layer 120 may be formed on at least one of the upper and lower portions of the transparent substrate 110. For example, the first adhesive layer 120 may be formed on both sides of a transparent substrate with a thickness of 10 μm.

The first adhesive layer 120 may be a transparent material, that is, transparent. For example, the first adhesive layer 120 may be any one of rubber, acrylic, silicone and urethane adhesives.

The metal layer 130 may be bonded to the transparent substrate 110 through the first adhesive layer 120.

The metal layer 130 may be formed by patterning on the first adhesive layer 120. For example, the metal layer 130 may be formed by patterning on the top of the first adhesive layer to a thickness of 36㎛.

The metal layer 130 may transmit power to an electronic device, for example, an LED device. For example, the metal layer 130 may be implemented as a copper layer (or a copper foil layer) to serve as electrical wiring.

As described above, the metal layer 130 may be a copper layer (or a copper foil layer), but is not limited thereto. For example, the metal layer 130 may include a nickel layer (Ni layer).

The second adhesive layer 140 may be formed on at least one of the upper portion of the metal layer 130 and the first adhesive layer 120. For example, the second adhesive layer 140 may have a thickness of 20 μm and be formed on at least one of an upper portion of a region in which the LED element is not attached and an upper portion of the first adhesive layer 120 in the region of the metal layer 130. have.

The second adhesive layer 140 may be a transparent material, that is, transparent. For example, the second adhesive layer 140 may be the same material as the first adhesive layer 120.

The second adhesive layer 140 may prevent corrosion and physical damage of the metal layer 130.

Accordingly, the second adhesive layer 140 may ensure transparency of the flexible printed circuit board 100 and protect a portion of the metal layer 130 exposed to the outside.

The via hole 150 may be formed on the transparent substrate 110. For example, the via hole 150 may be formed on the transparent substrate 110 to connect metal layers formed on both sides of the transparent substrate 110.

The flexible printed circuit board 100 may further include a conductive layer 160 and a solder (not shown).

The conductive layer 160 may be formed on the metal layer 130. For example, the conductive layer 160 may be formed on a region of the metal layer 130 with a thickness of 3 μm, on top of a region to which an LED element is attached. For example, the conductive layer 160 may be composed of at least one of a Ni layer and an Au layer.

Solder (not shown) may be formed on at least one of the upper portion of the metal layer 130 and the conductive layer 160. For example, solder (not shown) may be formed in at least one of an area of the metal layer 130 to which the LED element is attached, and an area of the conductive layer 160 to which an electronic device, for example, is attached.

The solder (not shown) may surface-mount an electronic device, for example, an LED device, on at least one of the metal layer 130 and the conductive layer 160. For example, the solder may surface mount the LED device on at least one of the top of the metal layer 130 and the top of the conductive layer 160 for surface mounting technology (SMT).

The solder (not shown) may be a solder bomp. For example, the solder (not shown) may be a low temperature Sn solder bump. The melting point of the low temperature Sn solder bump may be the melting point of the heat-resistant PET, that is, 160 ° C suitable for 180 ° C.

Figure 2 shows an example for explaining the process of the flexible printed circuit board shown in Figure 1, Figure 3 shows an example for explaining the metal layer pattern of the flexible printed circuit board shown in Figure 1, Figure 4 is FIG. 1 shows an enlarged view of region A of FIG. 1, FIG. 5 shows another example for explaining the process of the flexible printed circuit board shown in FIG. 1, and FIG. 6 shows a solder pattern of the flexible printed circuit board shown in FIG. Here is an example for explanation.

2, the process of the flexible printed circuit board 100 includes a preparation step (PREPARATION), step 1 (STEP1), step 2 (STEP2), step 3 (STEP3) and step 4 (STEP4).

In the preparation step (PREPARATION), the transparent substrate 110, the first adhesive layer 120, and the metal layer 130 may be prepared in a sheet form. For example, the transparent substrate 110 has a thickness of 120 μm and may be a heat-resistant PET film cut into 500 mm X 400 mm. The first adhesive layer 120 has a thickness of 10 μm and may be a bonding sheet film cut to 500 mm X 400 mm. The metal layer 130 is 18 μm thick and may be a copper foil film cut to 500 mm X 400 mm.

In step 1 (STEP1), the transparent substrate 110, the first adhesive layer 120, and the metal layer 130 may be pressed using a roller or the like while being attached to each other. For example, the structure consisting of the transparent substrate 100, the first adhesive layer 120 and the metal layer 130 may have a thickness of 148㎛.

In step 2 (STEP2), the finely patterned metal layer 130 may be formed.

For example, in step 2 (STEP2), a photoresist layer of the metal layer 130 pattern may be formed by at least one of irradiation and development nuclei of the photosensitive agent through a mask corresponding to the pattern of the metal layer 130.

Subsequently, in step 2 (STEP2), the metal layer 130 patterned in response to the mask pattern is performed by performing an etching process on the upper surface of the metal layer 130 in the portion without the photoresist and removing the photoresist layer through the etching process. Can form. At this time, the etching process may be a process using a photoresist.

As another example, in step 2 (STEP2), a fine copper (or fine copper foil) pattern having a line width of 75 μm and a line spacing may be formed using laser direct imaging (LDI).

The pattern of the metal layer 130 patterned on the upper and lower portions of the transparent substrate 110 may be the same as the pattern 1 (PATTERN1) of FIG. 3.

The surfaces of the first adhesive layer 120 formed through Step 1 (STEP1) and Step 2 (STEP2) may be non-uniform or uneven as illustrated in FIG. 4 due to the non-uniformity of the surface of the metal layer 130.

Among the regions of the first adhesive layer 120, the uneven region that is not covered by the patterned metal layer 130 may be exposed to the outside. The rugged area can adversely affect the transparency of the flexible printed circuit board 100.

In order to smoothly form the bumpy area, a planarization process (or operation) may be performed. However, the substrate made of heat-resistant PET is difficult to perform a planarization process (or operation).

In step 3 (STEP3) of FIG. 5, the second adhesive layer 140 of the same component as the first adhesive layer 120 is formed on the first adhesive layer 120 to form the unevenness of the first gradually layer 120. It is possible to make the area nonexistent.

In step 3 (STEP3), the second adhesive layer 140 may be applied and patterned on at least one of the top of the first adhesive layer 120 and the region of the metal layer 130 to which the LED element is not attached. . For example, the coating and patterning method may be a method in which a liquid adhesive having the same material and material as the first adhesive layer 120 is coated and patterned by an electronic printing method. The liquid adhesive may be a transparent resist (TR).

Accordingly, the first adhesive layer 120 and the second adhesive layer 140 may be formed as one integrated adhesive layer.

In step 4 (STEP), the conductive layer 160 may be formed by an electroless plating method. For example, in step 4 (STEP4), a conductive layer 160, which is at least one of the Ni layer and the Au layer, may be plated by electroless plating.

The process of the flexible printed circuit board 100 may further form a via hole 150 and solder (not shown).

The solder (not shown) formed on the upper and lower portions of the transparent substrate 110 may be the same as the pattern 2 (PATTERN2) of FIG. 6.

When the flexible printed circuit board 100 has completed the above-described process, the flexible printed circuit board 100 of FIG. 1 may be implemented as a result (RESULT) of FIG. 7.

8 is a schematic block diagram of a display system according to an embodiment.

Referring to FIG. 8, a display system 10 includes a flexible printed circuit board 100, an LED device 200, and a driving device 300.

The flexible printed circuit board 100 may be a transparent and flexible printed circuit board on which the LED element 200 is surface mounted. Since the flexible printed circuit board 100 of FIG. 8 is the same as the flexible printed circuit board 100 of FIG. 1, detailed description will be omitted.

The LED device 200 may be surface mounted on the flexible printed circuit board 100.

For example, the LED device 200 may be surface-mounted on at least one of the top of the metal layer 130 and the top of the conductive layer 160 of the flexible printed circuit board 100.

As another example, the LED device 200 may be surface mounted on the flexible printed circuit board 100 through Sn solder bumps formed on at least one of the upper portion of the metal layer 130 and the upper portion of the conductive layer 160.

The driving device 300 may control at least one of the LED element 200 and the flexible printed circuit board 100. For example, the driving device 300 may control the LED element 200 ON / OFF by controlling the flexible printed circuit board 100.

As described above, the LED element is an ON / OFF element, but is not limited thereto. For example, the LED element may be various display electronic devices such as a light emitting element capable of ON / OFF control.

The device described above may be implemented with hardware components, software components, and / or combinations of hardware components and software components. For example, the devices and components described in the embodiments include, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors (micro signal processors), microcomputers, field programmable gate arrays (FPGAs). , A programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions, may be implemented using one or more general purpose computers or special purpose computers. The processing device may run an operating system (OS) and one or more software applications running on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of understanding, a processing device may be described as one being used, but a person having ordinary skill in the art, the processing device may include a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that may include. For example, the processing device may include a plurality of processors or a processor and a controller. In addition, other processing configurations, such as parallel processors, are possible.

The software may include a computer program, code, instruction, or a combination of one or more of these, and configure the processing device to operate as desired, or process independently or collectively You can command the device. Software and / or data may be interpreted by a processing device, or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. , Or may be permanently or temporarily embodied in the transmitted signal wave. The software may be distributed on networked computer systems, and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiments or may be known and usable by those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. -Hardware devices specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described by a limited embodiment and drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques are performed in a different order than the described method, and / or the components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or other components Alternatively, even if replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (5)

A first printed circuit board area and a second printed circuit board area for attaching each of the LED elements; And
A via hole formed between the first printed circuit board area and the second printed circuit board area
Including,
Each of the first printed circuit board area and the second printed circuit board area,
Transparent substrates;
First adhesive layers formed on upper and lower portions of the transparent substrate;
A metal layer formed by patterning on each of the first adhesive layers; And
The second adhesive layer is formed on an upper portion of the remaining region to which the LED element is not attached, and an upper portion of each of the first adhesive layers in the region where the metal layer is not formed among the entire regions of each of the metal layers.
Including,
The via hole is a flexible printed circuit board that connects a side metal layer formed on a side of each transparent substrate formed in the first printed circuit board area and the second printed circuit board area.
According to claim 1,
Each of the first printed circuit board area and the second printed circuit board area,
A conductive layer formed on an upper portion of each region of the metal layer to which the LED element is attached; And
Solder for surface mounting the LED element on the metal layer and the conductive layer
Flexible printed circuit board further comprising.
According to claim 2,
The transparent substrate is flexible, heat-resistant PET (polyethylene tereohthalate),
The first adhesive layer is transparent,
The metal layer is at least one of a copper layer and a nickel layer,
The second adhesive layer is transparent, prevents corrosion and physical damage of the metal layer,
The conductive layer is at least one of the Ni layer and the Au layer,
The solder is a flexible printed circuit board for surface mounting technology (SMT).
LED element;
A flexible printed circuit board surface-mounting the LED element; And
A driving device that controls at least one of the LED element and the flexible printed circuit board
Including,
The flexible printed circuit board,
A first printed circuit board area and a second printed circuit board area for attaching each of the LED elements; And
A via hole formed between the first printed circuit board area and the second printed circuit board area
Including,
Each of the first printed circuit board area and the second printed circuit board area,
Transparent substrates;
First adhesive layers formed on upper and lower portions of the transparent substrate;
A metal layer formed by patterning on each of the first adhesive layers; And
A second adhesive layer formed on a region where the LED layer is not attached among the entire regions of each of the metal layers and a region where the metal layer is not formed among the first adhesive layers.
Including,
The via hole is a display system for connecting a side metal layer formed on a side of each transparent substrate formed in the first printed circuit board region and the second printed circuit board region.
According to claim 4,
Each of the first printed circuit board area and the second printed circuit board area,
A conductive layer formed on an upper portion of each region of the metal layer to which the LED element is attached; And
Solder for surface mounting the LED element on the metal layer and the conductive layer
Further comprising,
The transparent substrate is flexible, heat-resistant PET (polyethylene tereohthalate),
The first adhesive layer is transparent,
The metal layer is at least one of a copper layer and a nickel layer,
The second adhesive layer is transparent, prevents corrosion and physical damage of the metal layer,
The conductive layer is at least one of the Ni layer and the Au layer,
The solder is a display system for surface mounting technology (SMT).

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