TWI674059B - Circuit board using for a printed electronic component - Google Patents

Abstract

A circuit board suitable for printed electronic components includes a flexible substrate, at least one printed electronic component, a circuit layer, a protective layer, and at least one heat dissipation layer. Printed electronic components are stacked on a flexible substrate. The circuit is laminated on the flexible substrate, the circuit layer is electrically connected to the printed electronic component, and the circuit layer and the printed electronic component are located on the same side of the flexible substrate. The protective layer is arranged on the printed electronic component and the circuit layer, so that the printed electronic component and the circuit layer are located between the flexible substrate and the protective layer. The heat dissipation layer is disposed on the protective layer and the heat dissipation layer and the circuit layer are located on opposite sides of the protective layer, respectively, or the heat dissipation layer and the circuit layer are located on opposite sides of the flexible substrate. Among them, printed electronic components and circuit layers are made by printing methods.

Description

Circuit board suitable for printed electronic components

The invention relates to a circuit board suitable for printing electronic components, in particular to a circuit board with electronic components and circuit layers made of printing and having a heat dissipation layer.

With the development of the trend of flexible and thin consumer electronic products in the future, manufacturers have successively tried to apply flexible materials to substrates for circuit boards, and have tried to reduce the size of electronic components.

However, the thermal conductivity of common flexible materials is often too low, and the thermal conductivity of flexible substrates made from this material is also too low. When the reduced electronic components are stacked on the flexible substrate, the heat generated by the miniaturized electronic components during operation is not easily carried away by the flexible substrate. In this way, a large amount of heat of the miniaturized electronic component in a high-power state will gather around the electronic component, causing the temperature of the flexible substrate around the location of the electronic component to rise. The high temperature causes the flexible substrate to deform, causing the electronic components or circuit layers stacked on the flexible substrate to be warped and damaged, and the entire circuit board is unusable. When the problem of poor heat dissipation is more serious, it may even cause the flexible substrate to burn out.

The invention is to provide a circuit board suitable for printed electronic components, thereby solving the poor heat dissipation of the flexible substrate, so that the miniaturized electronic components stacked on the flexible substrate The generated heat is not easy to be taken away by the flexible substrate, which causes the entire circuit board to be damaged and cannot be used or even burned.

A circuit board suitable for printed electronic components disclosed in one embodiment of the present invention includes a flexible substrate, at least one printed electronic component, a circuit layer, a protective layer, and at least one heat dissipation layer. Printed electronic components are stacked on a flexible substrate. The circuit is laminated on the flexible substrate, the circuit layer is electrically connected to the printed electronic component, and the circuit layer and the printed electronic component are located on the same side of the flexible substrate. The protective layer is arranged on the printed electronic component and the circuit layer, so that the printed electronic component and the circuit layer are located between the flexible substrate and the protective layer. The heat dissipation layer is disposed on the protective layer and the heat dissipation layer and the circuit layer are located on opposite sides of the protective layer, or the heat dissipation layer is disposed on the flexible substrate and the heat dissipation layer and the circuit layer are located on opposite sides of the flexible substrate. Among them, printed electronic components and circuit layers are made by printing methods.

According to the circuit board suitable for printed electronic components disclosed in the present invention, the heat generated by the printed electronic components during work will be conducted away through the heat dissipation layer through the arrangement of the heat dissipation layer, thereby ensuring the flexible substrate and Printed electronic components are maintained in a temperature range in which they can operate normally. In this way, the thin and flexible circuit board can still be provided with high-power printed electronic components and function normally to increase the applicability of the thin and flexible circuit board.

The above description of the content of the present invention and the description of the following embodiments are used to demonstrate and explain the principle of the present invention, and provide further explanation of the scope of the patent application of the present invention.

10a, 10b, 10c‧‧‧Circuit board

100a, 100b, 100c‧‧‧ Flexible substrate

200a, 200b, 200c‧‧‧Printed electronic components

300a, 300b, 300c‧‧‧ Line Layer

400a, 400c‧‧‧protective layer

500a, 500b, 500c‧‧‧ heat dissipation layer

FIG. 1 is a schematic side view of a circuit board according to a first embodiment of the present invention.

FIG. 2 is a schematic side view of a circuit board according to a second embodiment of the present invention.

FIG. 3 is a schematic side view of a circuit board according to a third embodiment of the present invention.

The first embodiment of the present invention will be described below. Please refer to FIG. 1 first. FIG. 1 is a schematic side view of a circuit board according to a first embodiment of the present invention.

The circuit board 10a according to the first embodiment of the present invention includes a flexible substrate 100a, at least one printed electronic component 200a, a circuit layer 300a, a protective layer 400a, and a heat dissipation layer 500a. In the first embodiment of the present invention, the thickness of the flexible substrate 100a is 750 micrometers (μm) or less, but it is not limited thereto. In other embodiments of the present invention, the thickness of the flexible substrate may be 30 μm to 500 μm, so that the flexible substrate maintains better structural strength and has a better bending effect. The thickness of the flexible substrate is, for example, 50 μm, 100 μm, 150 μm or other thickness that allows the flexible substrate to maintain moderate flexibility. In the first embodiment of the present invention, the thermal conductivity of the flexible substrate 100a is, for example, 0.4 W / m. Below K, but not limited to this. In other embodiments of the present invention, the thermal conductivity of the flexible substrate is 0.1 to 0.4 W / m. K. In the first embodiment of the present invention, the material of the flexible substrate 100a is, for example, PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), or epoxy resin grease up to FR4. But not limited to this. In other embodiments of the present invention, the material of the flexible substrate may be other flexible polymer materials.

The printed electronic component 200a is stacked on the flexible substrate 100a. The thickness of the printed electronic component 200 a may be 1000 μm or less, for example, 8 μm, 20 μm, 80 μm, 200 μm, or 800 μm, so as to meet the requirement of thinning the circuit board 10 a. In the first embodiment of the present invention, the printed electronic component 200a is, for example, a capacitor, a resistor, or an inductor, but is not limited thereto. Uben In other embodiments of the invention, the printed electronic component may be other electronic components. In the first embodiment of the present invention, the printed electronic component 200a is manufactured by printing using conductive ink. The conductive ink is, for example, a conductive silver paste, a conductive copper paste, a conductive aluminum paste, or a conductive polymer material. The conductive polymer material includes PEDOT (Poly (3,4-ethylenedioxythiophene)), but it is not limited thereto. In other embodiments of the present invention, the conductive ink constituting the printed electronic component may be an oil-based ink including powder of gold, silver, copper, aluminum, platinum, alloys thereof, other metals, or other alloys.

In the first embodiment of the present invention, the printed electronic component 200a is manufactured in a printed form, such as screen printing, gravure printing, letterpress printing, or inkjet printing. Manufacture of the printed electronic component 200a in a printed form can save the man-hours of assembling the printed electronic component 200a on the flexible substrate 100a, thereby improving the efficiency of producing the circuit board 10a. In the first embodiment of the present invention, the conductive ink is printed on the flexible substrate 100a in a liquid form. After the liquid components such as the volatile solvent in the conductive ink are dried and removed, the remaining solid components are formed. Printed electronic component 200a. The conductive ink is dried by baking the conductive ink printed on the flexible substrate 100a at a temperature of, for example, 60 to 80 degrees Celsius. The baking time is, for example, 5 to 15 minutes, but is not limited thereto. In other embodiments of the present invention, the baking may be performed at a baking temperature or a baking time that does not cause deformation of the flexible substrate, or only the conductive ink is naturally dried.

The circuit layer 300a is stacked on the flexible substrate 100a, the circuit layer 300a is electrically connected to the printed electronic component 200a, and the circuit layer 300a and the printed electronic component 200a are located on the same side of the flexible substrate 100a. In the first embodiment of the present invention, the circuit layer 300a is made of conductive ink by printing. The conductive ink is, for example, a conductive silver paste, a conductive copper paste, A conductive aluminum paste or a conductive polymer material, wherein the conductive polymer material includes PEDOT (Poly (3,4-ethylenedioxythiophene)), but is not limited thereto. In other embodiments of the present invention, the conductive ink constituting the printed electronic component may be an oil-based ink including powder of gold, silver, copper, aluminum, platinum, alloys thereof, other metals, or other alloys. In the first embodiment of the present invention, the circuit layer 300a is manufactured in a printing form, such as screen printing, gravure printing, letterpress printing, or inkjet printing. Manufacturing the circuit layer 300a in a printed form can save man-hours and reduce environmental pollution compared to manufacturing the circuit layer in an electroplated form, thereby reducing the total cost of producing the circuit board 10a. In the first embodiment of the present invention, the conductive ink is printed on the flexible substrate 100a in a liquid form. After the liquid components such as the volatile solvent in the conductive ink are dried and removed, the remaining solid components are formed.线 层 300a。 Line layer 300a. The conductive ink is dried by baking the conductive ink printed on the flexible substrate 100a at a temperature of, for example, 60 to 80 degrees Celsius. The baking time is, for example, 5 to 15 minutes, but is not limited thereto. In other embodiments of the present invention, the baking may be performed at a baking temperature or a baking time that does not cause deformation of the flexible substrate, or only the conductive ink is naturally dried.

The protective layer 400a is stacked on the printed electronic component 200a and the circuit layer 300a by, for example, printing, spray coating, shower coating, bonding, plating, sputtering, electroplating, or electroless plating, so that the printed electronic component 200a and the circuit layer 300a are located on a flexible substrate. Between 100a and the protective layer 400a. In the first embodiment of the present invention, the material of the protective layer 400a is, for example, epoxy resin or acrylic, but it is not limited thereto. The protective layer 400a passes through a heat source such as an electric heating furnace or infrared radiation, and is dried and cured in a manner such as low-temperature baking. In other embodiments of the present invention, in order to accelerate curing of the protective layer during the manufacturing process, the material of the protective layer may further include an ultraviolet curing material. This UV curing material can be used as an initiator to accelerate the curing reaction. In other words, The material of the protective layer is, for example, an epoxy resin containing a UV-curable material or acrylic with a UV-curable material. The protective layer 400a covers the printed electronic component 200a and the circuit layer 300a and provides a stable environment for the printed electronic component 200a and the circuit layer 300a, thereby improving the weather resistance of the printed electronic component 200a. Through the setting of the protective layer 400a, the resistance change rate of the printed electronic component 200a can be maintained within 5% under the conditions of 65 degrees Celsius, 95% relative humidity, and 72 hours after the printed electronic component 200a is passed. In this way, the circuit board 10a using the printed electronic component 200a and provided with the protective layer 400a can expand the applicable environmental conditions.

The heat dissipation layer 500 a is stacked on the protection layer 400 a by, for example, printing, spray coating, shower coating, lamination, plating, sputtering, electroplating, or electroless plating, and the heat dissipation layer 500 a and the circuit layer 300 a are located on opposite sides of the protection layer 400 a, respectively. That is, the heat dissipation layer 500a is stacked on one side of the protective layer 400a away from the circuit layer 300a. The thickness of the heat radiation layer 500a is 1 μm or more. The material of the heat dissipation layer 500a is, for example, metal oxide, ceramic, graphene, silicon dioxide, silicon rubber, or polymer, and the metal oxide is, for example, zinc oxide or manganese oxide. The heat dissipation layer 500a is baked, for example, at a temperature of 80 degrees Celsius and the baking time is 10 minutes, so that the liquid components in the heat dissipation layer 500a are evaporated, and the remaining solid components are adhered to the protective layer 400a. The thermal conductivity of the heat dissipation layer 500a is greater than the thermal conductivity of the flexible substrate 100a, so it can more effectively conduct the heat generated by the printed electronic component 200a. The heat generated by the printed electronic component 200a is conducted to the heat dissipation layer 500a through the protective layer 400a for heat dissipation, so that the heat is evenly distributed and not excessively concentrated around the printed electronic component 200a, thereby ensuring that the flexible substrate 100a and the printed electronic component 200a are maintained normally. Operating temperature range. In the first embodiment of the present invention, the heat dissipation layer 500a has a single-layer structure, but is not limited thereto. In other implementations of the invention In an example, the heat dissipation layer may have a double-layer structure, for example, one layer is a metal layer and the other layer is an adhesive layer. The metal layer is adhered to one side of the protective layer away from the circuit layer through the adhesive layer. In other embodiments of the present invention, the heat-dissipating layer is, for example, a copper tape, and the heat-dissipating layer can be conveniently and quickly attached to one side of the protective layer away from the circuit layer.

The thermal conductivity of the aforementioned heat dissipation layer 500a is greater than the thermal conductivity of the flexible substrate 100a, that is, the thermal conductivity of the heat dissipation layer 500a exceeds 0.4 W / m. K. When the thermal conductivity of the heat dissipation layer 500a is only slightly over 0.4 W / m. At K, in order to ensure that the heat dissipation ability of the heat dissipation layer 500a can meet the heat dissipation requirements of common electronic components with a maximum power of 500 milliwatts (mW), the area of the heat dissipation layer 500a must be more than 1.875 times the area of the printed electronic component 200a. Among them, the thermal conductivity in the heat dissipation layer 500a is only slightly over 0.4 W / m. In the case of K, the relationship between A. the area of the heat dissipation layer 500a, B. the area of the printed electronic component 200a, and C. the maximum power of the printed electronic component 200a is shown in the following table. In addition, the ratio of the area of the heat-dissipating layer 500a to the area of the printed electronic component 200a can also be obtained from the following table.

It can be known from the above table that if the circuit board 10a is not provided with a heat dissipation layer 500a, that is, the first item in the above table, the maximum power of the selected C. printed electronic component 200a can only reach 322mW, It does not meet the requirement that the maximum power of C. printed electronic component 200a should reach 500mW. If the heat dissipation layer 500a is provided on the circuit board 10a, it can be known from the above table that when the area of the heat dissipation layer 500a is larger, the maximum power of the selected C. printed electronic component 200a can also be higher. However, if the ratio of the area of the heat dissipation layer 500a to the area of the printed electronic component 200a is less than 1.875 times, for example, the second item in the table above, the maximum power of the printed electronic component 200a is only 400mW, which cannot meet the demand of more than 500mW. . If the ratio of the area of the heat-dissipating layer 500a to the area of the printed electronic component 200a reaches 100 times, that is, the last item in the table above, the heat-dissipating capacity of the heat-dissipating layer 500a can meet the maximum power of the printed electronic component 200a of 1428mW.

The heat dissipation layer 500a of the above embodiment is stacked on the protection layer 400a and the heat dissipation layer 500a and the circuit layer 300a are located on opposite sides of the protection layer 400a, but not limited thereto. Please refer to FIG. 2, which is a schematic side view of a circuit board according to a second embodiment of the present invention. In the following, only the differences between the second embodiment of the present invention and the first embodiment of the present invention will be described, and the remaining same parts will be omitted. In the second embodiment of the present invention, the heat dissipation layer 500b of the circuit board 10b is stacked on the flexible substrate 100b, and the heat dissipation layer 500b and the circuit layer 300b are located on opposite sides of the flexible substrate 100b, respectively. That is, the heat dissipation layer 500b is stacked on one side of the flexible substrate 100b away from the wiring layer 300b. The heat generated by the printed electronic component 200b is conducted to the heat radiation layer 500b through the flexible substrate 100b to be radiated.

The heat dissipation layer 500a of the above embodiment is stacked on the protection layer 400a and the heat dissipation layer 500a and the circuit layer 300a are located on opposite sides of the protection layer 400a, respectively, or the heat dissipation layer 500b is stacked on the flexible substrate 100b and the heat dissipation layer 500b and the circuit layer 300b is located on two opposite sides of the flexible substrate 100b, but is not limited thereto. Please refer to FIG. 3, which is a schematic side view of a circuit board according to a third embodiment of the present invention. The following is only directed to the third embodiment of the present invention. The difference between this embodiment and the first embodiment of the present invention will be described, and the remaining same parts will be omitted. In the third embodiment of the present invention, the number of the heat dissipation layers 500c of the circuit board 10c is two. Two heat dissipation layers 500c are respectively stacked on the protection layer 400c and the flexible substrate 100c, and the heat dissipation layer 500c and the circuit layer 300c are located on opposite sides of the protection layer 400c, respectively. In other words, the two heat dissipation layers 500c are stacked on one side of the protective layer 400c away from the circuit layer 300c and one side of the flexible substrate 100c away from the circuit layer 300c, respectively. Alternatively, the outermost opposite sides of the circuit board 10c are both a heat dissipation layer 500c. Since the heat generated by the printed electronic component 200c can be transferred to the outermost heat dissipation layers 500c through the protective layer 400c and the flexible substrate 100c, the heat dissipation effect is better.

According to the circuit board of the above embodiment, in order to solve the problem of poor heat dissipation of the circuit board after the circuit board is flexible and thinned, a heat dissipation layer is arranged on the outermost layer of the circuit board. If the thermal conductivity of the heat dissipation layer is only slightly over 0.4W / m. The heat dissipation layer must meet the 500mW heat dissipation requirements of common electronic components, and the area of the heat dissipation layer must be 1.875 times the area of the printed electronic components. In this way, the heat dissipation layer can effectively and evenly disperse the heat generated during the operation of the printed electronic component. The heat dissipation layer is provided so that the heat is not excessively concentrated on the printed electronic component, thereby ensuring that the flexible substrate and the printed electronic component are maintained in a normal operating temperature range. In this way, the maximum power of the printed electronic components used can reach more than 500mW, which is the minimum required standard for general use of electronic components, to match the various use cases of the circuit board and increase the applicability of the circuit board.

Although the present invention is disclosed as above with the foregoing embodiments, it is not intended to limit the present invention. Any person skilled in similar arts can make some changes and retouch without departing from the spirit and scope of the present invention. The scope of patent protection of an invention shall be determined by the specification The attached application patent shall prevail.

Claims (10)

A circuit board is suitable for printed electronic components. The circuit board includes: a flexible substrate; at least one printed electronic component is stacked on the flexible substrate; a circuit layer is stacked on the flexible substrate; The at least one printed electronic component is electrically connected, and the circuit layer and the at least one printed electronic component are located on the same side of the flexible substrate; a protective layer is stacked on the at least one printed electronic component and the circuit layer so that the At least one printed electronic component and the circuit layer are located between the flexible substrate and the protective layer; and at least one heat dissipation layer is stacked on the protective layer so that the at least one printed electronic component and the circuit layer are between the flexible layer Between the substrate and the at least one heat-dissipating layer; wherein the at least one printed electronic component and the circuit layer are made by printing. The circuit board according to item 1 of the scope of patent application, wherein the number of the heat dissipation layers is two, and the two heat dissipation layers are respectively stacked on the protection layer and the flexible substrate, and the heat dissipation layer and the circuit layer are respectively located on the Opposite sides of the protective layer. The circuit board according to item 1 of the scope of patent application, wherein the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the flexible substrate. The circuit board according to item 1 of the scope of patent application, wherein the area of the heat dissipation layer is more than 1.875 times the area of the at least one printed electronic component. The circuit board according to item 1 of the scope of patent application, wherein the thickness of the heat dissipation layer is 1 micrometer (μm) or more. The circuit board according to item 1 of the scope of patent application, wherein the material of the heat dissipation layer is The material is metal oxide, ceramic, graphene, silicon dioxide, silicone, or polymer. The circuit board according to item 1 of the scope of patent application, wherein the heat dissipation layer is laminated on the flexible substrate or the protective layer by printing, spraying, shower coating, laminating, plating, sputtering, electroplating, or galvanizing. The circuit board according to item 1 of the scope of patent application, wherein the material of the circuit layer is a conductive ink. The circuit board according to item 1 of the scope of patent application, wherein the thickness of the at least one printed electronic component is 1000 micrometers (μm) or less. The circuit board according to item 1 of the scope of patent application, wherein the thickness of the flexible substrate is 750 micrometers (μm) or less.