TWI656027B - White cover film for led substrate and led substrate using the same - Google Patents

Abstract

A white cover film and an LED substrate, the white cover film comprising a white ink layer having a surface roughness of 50 to 10000 nm; and a release layer formed on the white ink layer, the contact surface of the white ink layer a surface roughness of 0.2 to 10 μm; a lower release layer; and an adhesive layer formed between the lower release layer and the white ink layer, and the total thickness of the white ink layer and the adhesive layer is 4 to 50 microns. The white cover film of the invention has low dielectric constant and loss, low transmittance, low gloss, low rebound force, high ion purity, high reflectivity, high flexibility, high surface hardness, high temperature yellowing resistance and weather resistance The characteristics of goodness are suitable for LED lighting of soft and hard board. The present invention discloses an LED substrate using the white cover film.

Description

 White cover film for LED substrate and LED substrate using the same  

The present invention relates to a cover film for an LED (light emitting diode), and more particularly to a white cover film for an LED substrate and an LED substrate using the white cover film.

With the development of the information and communication industry, the Flexible Printed Circuit (FPC), which has driven the rapid development of the microelectronics industry, has emerged as the times require, and has been rapidly developed. It has been obtained in many fields such as mobile phones, LCD monitors, and tablets. widely used. The biggest difference between a flexible printed circuit board and a PCB (Printed Circuit Board) is that the former uses a cover film. Unlike the solder resist ink used for PCBs, it not only has a solder resist effect, but also makes the FPC not dust, moisture, The erosion of chemicals can also reduce the effects of stress during bending. In addition, with the development of the FPC market, the cover film has been given more functions, in which the white cover film has high reflectivity, low transmittance, high temperature resistance, weather resistance and the like to achieve the shielding effect, and is strongly applied in LED light bar area. In the current global energy shortage, energy conservation is an important issue for us in the future. In the field of lighting, the application of LED lighting products is attracting the attention of the world. As a new type of green light source, LED is bound to be the future development. Trends, the 21st century will enter the era of new lighting sources represented by LED.

At present, the conventional process of the white LED strip product is selected from one of the following groups of methods: First: as shown in FIG. 1, the cover film is pressed against the substrate after being opened, and then dried at a low temperature. Applying a layer of white ink A100 on the surface to improve the contrast of the LED product to enhance the printing effect, but the disadvantage is that the printing thickness is uneven and the flexibility is poor; the second: as shown in Figure 2 The white ink cover film is directly attached to the flexible printed circuit board, and the white ink cover film includes a first white ink layer B100, a yellow PI (polyimine) layer B200, and a first adhesive layer B300. The first release layer B400 can achieve the purpose of reducing the downstream process, but the white ink cover film has poor resistance to high temperature yellowing and is difficult to achieve thinning; the third type: as shown in Fig. 3, covered with white PI The film is directly attached to the flexible printed circuit board, and the white PI coating film comprises a white PI layer C100, a white adhesive layer C200 and a second release layer C300, which has high temperature resistant yellowing, good weather resistance and high reflection. The characteristics of the rate, but its cost is high and the thinning is difficult to achieve .

In order to meet the needs of the market, the present invention aims to develop an ultra-thin white cover film which has high reflectivity, high temperature yellowing resistance, low repulsive force and low manufacturing cost and is suitable for use in the field of LED illumination.

The invention provides a white cover film for an LED substrate and an LED substrate using the white cover film, which has extremely low dielectric constant and loss, low rebound force, low transmittance, low gloss, extremely high ion purity and high Ultra-thin white cover film with high reflectivity, high flexibility, high surface hardness, high temperature yellowing resistance and weather resistance for high performance LED lighting of soft and hard bonded boards.

The present invention provides a white cover film for an LED substrate, comprising: a lower release layer; an adhesive layer having a thickness of 3 to 25 microns, formed on the lower release layer; having a thickness of 1 to 25 μm and surface roughness a white ink layer having a (Rz value) of 50 to 10,000 nm is formed on the adhesive layer such that the adhesive layer is between the lower release layer and the white ink layer, and the white ink layer and the subsequent layer The total thickness of the agent layer is 4 to 50 micrometers; and the upper release layer is formed on the white ink layer, and the surface roughness (Rz value) of the side of the upper release layer in contact with the white ink layer It is 0.2 to 10 microns.

In one embodiment, the total thickness of the white ink layer and the adhesive layer is 6 to 15 microns, wherein the white ink layer has a thickness of 3 to 5 microns, and the adhesive layer is The thickness is 3 to 10 microns.

In another embodiment, the white ink layer is an ink layer containing a matting powder.

In one embodiment, the adhesive layer is a glue layer, wherein the adhesive layer has a dielectric constant (Dk value) of 2.4 to 2.8 at a measurement frequency of 10 GHz, and is measured at a frequency of 10 GHz. The dielectric loss (Df value) is 0.002 to 0.006, and its interline insulation resistance is greater than 10 ¹¹ ohms (Ω), its surface resistance is greater than 10 ¹² ohms (Ω), and its volume resistance is greater than 10 ¹³ ohm-cm (Ω). -cm).

In one embodiment, the upper release layer and the lower release layer are each selected from the group consisting of a polypropylene release layer, a biaxially oriented polypropylene release layer, and a polyethylene terephthalate release. One of the groups consisting of layers.

The present invention provides an LED substrate comprising: a base layer; and an adhesive layer and a white ink layer according to the present invention, and the white ink layer is located between the base layer and the adhesive layer.

The effects of the present invention have at least the following points:

1. The white ink layer of the present invention has a matting effect on the ink layer containing the matting powder, so that the white ink layer exhibits a matte state. In addition, the degree of extinction of the surface of the coating film can be adjusted by controlling the particle size of the powder. The smaller the particle size of the matting powder, the larger the surface gloss (gloss) value, that is, the brighter the surface morphology, by adjusting the matting powder. The particle size, type and content, etc., to obtain the desired product (such as gloss, flame resistance, hardness or cost, etc.), and the addition of matting powder to further enhance the hardness of the white ink layer, so that the product has a higher Good mechanical properties, electrical performance and operability.

2. The release layer of the present invention is a matte release film, and the surface roughness (Rz value) of the contact surface with the white ink layer is 0.2 to 10 μm, and the roughness of the release film is passed through to cover The white ink layer of the film is easier to separate from the upper release layer, thereby improving the operability of the downstream terminal. At the same time, after the cover film is formed by rapid compression and the release film is peeled off, the matte release film contributes to the white ink. The surface morphology of the layer is in the form of extinction.

3. The total thickness of both the white ink layer and the adhesive layer of the present invention is from 4 to 50 microns, preferably from 6 to 15 microns, to meet the design requirements of current FPC thin wire lines.

Fourth, the invention has a low rebound force and is suitable for downstream high-density assembly processes.

5. The invention is composed of a white ink layer and an adhesive layer. The structure is reasonable and simple, and the process of coating a layer of white ink on the cover film on the FPC is reduced, thereby saving manpower and reducing production cost.

6. The white ink layer of the present invention does not cause yellowing in the process of rapid pressure, cover film curing and SMT in the FPC process, and the surface has the protection of the upper release layer without being contaminated, discolored or contaminated. There will be no abnormal phenomena such as etching and electroplating penetration, which will improve the yield of the product.

100‧‧‧White ink layer

200‧‧‧ adhesive layer

300‧‧‧Upper release layer

400‧‧‧Under release layer

500‧‧‧ basal layer

A100‧‧‧White ink

B100‧‧‧First white ink layer

B200‧‧‧Yellow PI (polyimine) layer

B300‧‧‧First adhesive layer

B400‧‧‧First release layer

C100‧‧‧White PI layer

C200‧‧‧White adhesive layer

C300‧‧‧Second release layer

Embodiments of the present invention are illustrated by way of example with reference to the accompanying drawings: FIG. 1 is a schematic structural view of a white ink layer; FIG. 2 is a schematic view showing a structure of a conventional white ink cover film attached to a flexible printed circuit board; 3 is a schematic structural view of a conventional white PI cover film attached to a flexible printed circuit board; FIG. 4 is a schematic structural view of a white cover film of the present invention; and FIG. 5 is a schematic structural view of the LED substrate of the present invention. .

The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily understand the advantages and functions of the present invention from the disclosure.

It is to be understood that the structure, the proportions, the size, and the like of the present invention are intended to be used in conjunction with the disclosure of the specification, and are not intended to limit the invention. The conditions are limited, so it is not technically meaningful. Any modification of the structure, change of the proportional relationship or adjustment of the size should remain in this book without affecting the effects and the objectives that can be achieved by the present invention. The technical content disclosed in the invention can be covered. In the meantime, the terms "a", "lower" and "upper" are used in this specification for the purpose of description and are not intended to limit the scope of the invention. Substantially changing the technical content is also considered to be within the scope of the invention. In addition, all ranges and values herein are inclusive and combinable. Any value or point falling within the ranges recited herein, such as any integer, may be the minimum or maximum value to derive the lower range and the like.

As shown in FIG. 4, the present invention provides a white cover film for an LED substrate, comprising: a lower release layer 400; an adhesive layer 200 having a thickness of 3 to 25 microns, formed on the lower release layer 400; A white ink layer 100 having a thickness of 1 to 25 μm and a surface roughness (Rz value) of 50 to 10,000 nm is formed on the adhesive layer 200 such that the adhesive layer 200 is located on the lower release layer 400. Between the white ink layers 100, and the total thickness of the white ink layer 100 and the adhesive layer 200 are 4 to 50 micrometers; and the upper release layer 300 is formed on the white ink layer 100, and the upper layer The surface of the release layer 300 in contact with the white ink layer 100 has a surface roughness (Rz value) of 0.2 to 10 μm.

In one embodiment, the total thickness of the white ink layer 100 and the adhesive layer 200 is 6 to 15 micrometers, wherein the white ink layer has a thickness of 3 to 5 micrometers, and the adhesive The thickness of the layer is from 3 to 10 microns.

In another embodiment, the white ink layer 100 is an ink layer containing a matting powder, and the matting powder has a D90 particle size of 2 to 12 microns.

In another embodiment, the matting powder system is selected from the group consisting of inorganic compounds, organic compounds, and flame retardant compounds, and the inorganic compound is selected from the group consisting of calcium sulfate, cerium oxide, At least one of a group consisting of titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, boron nitride, aluminum hydroxide, aluminum oxide, talc, aluminum nitride, glass powder, quartz powder, silicon carbide, and clay, the organic The compound is a polyimide-based resin, and the flame-retardant compound is at least one selected from the group consisting of halogen-containing, phosphorus-based compounds, nitrogen-based compounds, and boron-based compounds.

In one embodiment, the adhesive layer 200 is a glue layer, wherein the adhesive layer has a dielectric constant (Dk value) of 2.4 to 2.8 at a measurement frequency of 10 GHz, and the frequency is measured at 10 GHz. The dielectric loss (Df value) is 0.002 to 0.006, and its interline insulation resistance is greater than 10 ¹¹ ohms (Ω), its surface resistance is greater than 10 ¹² ohms (Ω), and its volume resistance is greater than 10 ¹³ ohm-cm ( Ω-cm).

In one embodiment, the upper release layer 300 and the lower release layer 400 are each selected from the group consisting of a polypropylene release layer, a biaxially oriented polypropylene release layer, and polyethylene terephthalate. One of the groups consisting of the release layers.

As shown in FIG. 5, the present invention provides an LED substrate comprising a base layer 500; and an adhesive layer 200 and a white ink layer 100 according to the present invention, and the white ink layer 100 is located on the base layer 500 and Between the adhesive layers 200.

In a specific embodiment, the white ink layer 100 has a white ink layer of HB to 5H, and the hardness is preferably 2H to 5H.

In another embodiment, the white ink layer 100 has a 60° gloss of 0 to 50 GU, preferably 5 GU.

Example 1:

The white ink raw material includes inorganic pigments and organic pigments, wherein aniline black and peptide blue are used as organic pigments, and the ratio of the ratio of the organic pigments to the total solid content is 10% by weight, and titanium dioxide and carbon black are selected as inorganic pigments. The sum of the proportions of the inorganic pigments accounts for 35% by weight of the total solid content, and the remaining proportions are mixed with butadiene cyanide rubber, methyl ethyl ketone solvent and resin to prepare a white ink raw material.

Applying the above white ink raw material to the designated release surface of the upper release layer, and curing the white ink raw material at 120 ° C to form a white ink layer having a thickness of 3 μm, and the surface roughness of the white ink layer ( The Rz value is about 6.4 microns.

Next, a sintered cerium oxide, a Teflon, a fluorine-based resin, a phosphorus-based flame retardant, and a polyimide resin are used as the material of the adhesive layer, wherein the polyimide resin is dielectric at a measurement frequency of 10 GHz. The constant (Dk) is 2.4 and the dielectric loss (Df) is 0.003, the water absorption is 0.05%, the interline insulation resistance is >10 ¹¹ ohms (Ω), the surface resistance is >10 ¹² ohms (Ω), and the volume resistance is >10 ¹³ ohms. - cm (Ω-cm). The sum of the ratio of the sintered cerium oxide, the Teflon, the fluorine-based resin and the phosphorus-based flame retardant is 15% by weight of the total solid content of the adhesive layer, and the ratio of the polyimide resin is 50% by weight. %; an adhesive layer was formed on the white ink layer by a coating method to form a 3 micron thick adhesive layer. Finally, the white ink layer is coated with polypropylene as the upper release layer, and the polypropylene coated on the adhesive layer is used as the lower release layer, thereby obtaining an ultra-thin white cover film product, wherein The upper release layer is a matte release film, and the surface roughness (Rz value) of the contact surface of the matte release film and the white ink layer is about 6.7 μm.

The ultra-thin white cover films of Examples 2 to 3 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1, except that only the thickness of the spacer white ink layer and the adhesive layer were as shown in Table 1, and the ultra-thin white cover film was tested. Surface hardness, high temperature yellowing resistance ΔL value, 60° gloss and reflectance at 500 nm wavelength are recorded in Table 1.

testing method:

(1) Surface hardness: The surface hardness was measured according to the color paint and varnish pencil method of GB/T 6739-2006.

(2) High temperature and yellowing resistance △L value: Performed according to the standard test method of ASTM E308. Place the product at 265 ° C for 15 to 20 minutes, and then use a color difference meter (Model: CM-2300D; purchased from KONICA MINOLTA) The △L value before and after the measurement test requires a ΔL value of less than 1.5 in order to achieve high temperature and yellowing resistance.

(3) 60° gloss: performed with a gloss instrument (model 4440; purchased from BYK, Germany) and according to the standard test method of ISO 2813 or JIS Z 8741, which uses an angle of 60° to the normal of the incident surface. The incident light is measured on the surface of the white ink layer, and the value of the surface gloss is read and recorded.

(4) Reflectance at a wavelength of 500 nm: The reflectance was measured by an integrating sphere spectrometer (SP60; X-Rite) according to the standard test method of GB9271-88.

As can be seen from Table 1, the white cover film of the present invention is formed by laminating a white ink layer and an adhesive layer, and has not only ultra-thin thickness, but also high surface hardness, low gloss, and low temperature resistance. Yellow and has a high reflectivity greater than 85%.

The ultra-thin white cover film of the sample samples 1 to 3 was prepared in the same manner as in Example 1, except that the type, content, average particle diameter of the matte powder and the surface roughness of the release layer were as shown in Table 1, and A commercially available white polyimine film was used as a comparative example, and the 60° gloss of the ultra-thin white cover film was tested and recorded in Table 2.

As can be seen from Table 2, the roughened release layer helps to reduce the gloss of the finished product, and the powder having a large average particle diameter is added to the white ink layer, and the gloss of the white ink layer can also be lowered.

The release layer and the lower release layer on the ultra-thin white cover film of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 3 were peeled off, and a flexible printed circuit board (FPC) was used as a base layer, and a white ink was used. The layer is directly attached to a flexible printed circuit board (FPC). As shown in the structure of FIG. 5, the white ink layer is placed between the FPC and the adhesive layer to form an LED substrate, and the rebound force is tested. The thickness is reported in Table 3.

As can be seen from Table 2, the product obtained by the white cover film for the ultra-thin FPC has a rebounding force much smaller than that of the comparative example, and the rebounding force is less than 5.0 gram.

The above embodiments are merely illustrative and are not intended to limit the invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the present invention is defined by the scope of the appended claims, and should be construed as being

Claims (6)

A white cover film comprising: a lower release layer; an adhesive layer having a thickness of 3 to 25 μm formed on the lower release layer; and a white ink layer having a thickness of 1 to 25 μm formed in the layer The adhesive layer is disposed between the lower release layer and the white ink layer, and the total thickness of the white ink layer and the adhesive layer is 4 to 50 micrometers; and the upper release layer is Formed on the white ink layer, and the surface of the upper release layer in contact with the white ink layer has a surface roughness (Rz value) of 0.2 to 10 μm, and the side of the white ink layer in contact with the upper release layer The surface roughness (Rz value) is from 50 to 10,000 nm. The white cover film of claim 1, wherein the white ink layer and the adhesive layer have a total thickness of 6 to 15 μm, and the white ink layer has a thickness of 3 to 5 μm. The thickness of the subsequent layer is from 3 to 10 microns. The white cover film of claim 1, wherein the white ink layer comprises a matte powder. The white cover film according to claim 1, wherein the adhesive layer has a dielectric constant (Dk value) of 2.4 to 2.8 at a measurement frequency of 10 GHz, and the dielectric is measured at a frequency of 10 GHz. Loss (Df value) is 0.002 to 0.006, and its line-to-line insulation resistance is greater than 10 ¹¹ ohms (Ω), its surface resistance is greater than 10 ¹² ohms (Ω), and its volume resistance is greater than 10 ¹³ ohm-cm (Ω-cm) . The white cover film of claim 1, wherein the material forming the upper release layer and the lower release layer are independently selected from the group consisting of polypropylene, biaxially oriented polypropylene, and polyethylene terephthalate. One of the groups consisting of esters. An LED substrate manufactured using the white cover film of claim 1, comprising: a base layer; and the adhesive layer and the white ink layer according to claim 1 of the patent application, and A white ink layer is between the substrate layer and the adhesive layer.