JP2016115517A - Transparent heat radiation member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent heat radiation member excellent in transparency and heat radiation and having high flexibility.SOLUTION: A transparent heat radiation member includes at least one metal pattern layer having a continuous shape on at least one surface of a transparent substrate. The metal pattern layer having a continuous shape has a mesh-like or a plurality of openings, and its opening shape is preferably an ellipse. The metal pattern layer is preferably formed by a pattern plating transcription method.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a transparent heat radiating member.

  In fields such as organic EL lighting, a material having both transparency and flexibility and excellent heat dissipation is eagerly desired. In a projector of a display device, a transparent filter is used to protect optical devices such as a lens and a laser in order to prevent dust and dust from adhering to a part of the projector. Plastic materials that are difficult to break are used.

JP 2012-150960 A JP 2005-156607 A

However, with the spread of augmented reality (AR) and projection mapping in recent years, the amount of light of the projector has become very large, and the temperature of the plastic material used for the transparent filter has risen, causing problems such as distortion. It was happening. Therefore, a flexible material with high transparency and heat dissipation has been eagerly desired.
An object of this invention is to provide the transparent heat radiating member which is excellent in transparency and heat dissipation, and has high flexibility.

The present invention relates to [1] a transparent heat radiating member in which at least one metal pattern layer having a continuous shape is provided on at least one surface of a transparent substrate.
The present invention also relates to [2] the transparent heat radiating member according to [1], wherein the metal pattern layers having a continuous shape are arranged in a mesh shape.
Further, the present invention provides [3] The metal pattern layer having a continuous shape, wherein the metal pattern layer has a plurality of openings, and the opening shape is an ellipse. The present invention relates to a transparent heat dissipation member.
[4] The transparent heat-radiating member according to any one of [1] to [3], wherein the metal pattern layer having a continuous shape is formed by a pattern plating transfer method. About.

  The transparent heat radiating member of the present invention is excellent in heat dissipation while being transparent and having high flexibility.

It is the upper surface schematic explaining the metal pattern layer of one continuous shape of the transparent heat radiating member of this embodiment, (a) is the form arrange | positioned in a mesh form, (b) is arrange | positioned in a honeycomb (honeycomb) form. (C) is the figure which showed the form arrange | positioned in the perforated shape (ellipse shape) of a different diameter. It is the upper surface schematic which showed the peripheral part of the transparent heat radiating member of this embodiment, (a) shows the whole peripheral part shape from the continuous shape metal pattern layer, (b) is the figure which showed the part . It is the upper surface schematic diagram explaining the metal pattern layer of several continuous shapes of the transparent heat radiating member of this embodiment, (a) is the form by which four metal pattern layers of the continuous shape are arrange | positioned, (b) is continuous. 8 is a view showing a form in which eight metal pattern layers having a shape are arranged, and FIG. 8C is a view showing a form in which a plurality of metal pattern layers having a continuous shape are arranged. It is the cross-sectional schematic diagram of the transparent heat radiating member of this embodiment, and the figure which showed the metal pattern layer. The figure which showed the cross-sectional schematic diagram of the transparent heat radiating member of this embodiment.

Examples of the metal of the metal pattern layer used for the transparent heat radiating member of the present embodiment include copper, silver, gold, nickel, aluminum, tin, indium, and alloys thereof.
The thermal conductivity is more preferably 10 W / mK or more, and the thermal conductivity is more preferably 100 W / mK or more in that heat can be efficiently dissipated in both the vertical and horizontal directions. The thickness of the metal pattern layer is preferably 3 to 30 μm, more preferably 3 to 15 μm, and still more preferably 3 to 10 μm, in view of reducing the thickness of the transparent heat radiating member. Such a metal pattern layer can be produced by a method of punching a metal foil, an electroforming method, a pattern plating transfer method, a method of removing unnecessary portions of the metal foil by etching, or the like.

  Of these, the pattern plating transfer method prepares a plate with an insulating resist so that the metal pattern is exposed from the metal plate on the metal plate (plate) to be plated, and then the underlying metal pattern is exposed by electrolytic plating. The metal pattern is formed on the transparent substrate with the adhesive layer, and the metal pattern is transferred to the transparent substrate with the adhesive layer by peeling off the metal pattern. It peels from (plate) and forms the metal pattern of a predetermined shape. The pattern plating transfer method is preferable in that a plate can be used repeatedly and a fine pattern can be formed at low cost.

  Examples of the metal plating include metals such as copper, silver, gold, nickel, aluminum, tin, and various alloys, but copper is preferable because it is inexpensive and has excellent thermal conductivity.

If the metal on the surface of the metal layer constituting the metal pattern layer is generally flat, the transparent heat radiating member can be flattened, which is preferable in that the image can be displayed without distortion. Here, in the transparent heat radiating member of the dimension to be used, the thickness of 10 portions of the metal layer is measured, and the average thickness X, the thin portion thickness Y, and the thickest portion thickness Z are as follows: (ZY) / X is 0.3 or less. A two-dimensional metal fiber structure such as a knitted or woven metal fiber is not preferable in terms of large irregularities. In addition, the metal pattern layer needs to have a structure having 50 to 97% of the entire area (light transmission portion) other than the metal pattern layer. More preferably, it is 80 to 95%.
When there are few parts other than a metal pattern layer, since transparency will fall, it cannot be used as a transparent member. The transparency of the transparent member means that it is transparent to light rays, and is preferably colorless and transparent, but may be colored and transparent.
If the portion other than the metal pattern layer exceeds 97%, the transparency will be improved, but the heat dissipation will be reduced, so that the temperature will rise and it will be easily deformed. It is preferable that many portions other than the metal pattern layer have a uniform density over the transparent heat radiating member. The shape of the continuous metal pattern layer may be any shape such as a circle, a quadrangle, a polygon, and a jagged shape, and the shape of the metal pattern layer having a portion other than the metal pattern layer is as shown in FIG. , (B) a honeycomb (honeycomb) shape, and (c) a perforated shape (elliptical shape) with different diameters.
As described above, the metal pattern layer (metal part) may be produced by any method such as etching, plating, pattern plating transfer method, punching, etc., but the pattern plating transfer method is effective in that it can be produced efficiently and continuously. preferable.
Further, the metal pattern needs to be continuous so that heat can be released from the end portion. Here, continuous means that a pattern can be reached from any point in the pattern to any other point, but a slightly discontinuous pattern may occur during manufacturing. It was defined that 95% or more of the area was continuous. In particular, it is preferable that the pattern of the end portion of the heat dissipation member can be reached through the pattern from an arbitrary point of the pattern.

In addition, it is necessary to release heat from the end of the transparent heat radiating member to the housing, the heat radiating plate, the heat pipe, and the like. Therefore, as shown in FIG. 2, it is preferable to increase the area of the metal part in the peripheral part (end part) of the transparent heat radiating member, or to thicken the pattern. In particular, by increasing the area of the metal part in the peripheral part (end part) where no light is irradiated or by increasing the thickness of the pattern, the heat dissipation can be enhanced without reducing the transmittance.
The above-mentioned correspondence may be made for the entire peripheral part (end part), but in the case of a part of the peripheral part (end part), for example, a rectangle, only one to three sides may be used.

The width of the pattern of the metal pattern layer is preferably 1 μm to 1 mm or less. If it is less than 1 μm, the heat dissipation is low, and if it exceeds 1 mm, the transmittance is not preferable. More preferably, it is 3-200 micrometers.
In addition, the thickness of the wiring does not need to be uniform. Rather, a thick line is placed in a part where heat is to be transferred over a wide area, and a thin line is placed in a part where heat is to be transferred locally, thereby improving transparency. It is preferable to efficiently release heat so that local high temperature portions (hot spots) are not generated while maintaining. For example, there is a pattern shown in FIG. 3 in which a portion that releases heat over a wide area and a fine mesh are combined with a tree-like pattern (a pattern in which a thick trunk and a thin branch are combined).
The transparent heat radiating member is not a single metal pattern layer, but is provided on at least one surface of a transparent substrate, and is used in a state where the transparent substrate and the metal pattern layer are bonded.
Examples of such a transparent substrate include a plate made of glass, plastic, and the like, and a plastic film. As the glass, glass such as soda glass, non-alkali glass, and tempered glass can be used. Examples of the plastic include thermoplastic resins and thermosetting resins such as polystyrene resin, acrylic resin, polymethyl methacrylate resin, polycarbonate resin, and polyethylene terephthalate resin.

The transparent substrate in the present invention is preferably a plastic film. The plastic film includes polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene, polypropylene, polystyrene, and EVA, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polysulfone, and polyethersulfone. A film made of plastic such as phon, polycarbonate, polyamide, polyimide, acrylic resin, etc., having a total visible light transmittance of 70% or more is preferable. These can be used as a single layer, but may be used as a multilayer film in which two or more layers are combined. Among the plastic films, a polyethylene terephthalate film or a polycarbonate film is more preferable in terms of transparency, heat resistance, ease of handling, and cost.
Although there is no restriction | limiting in particular in the thickness of the said plastic film, The thing of 1 mm or less is preferable, and when it is too thick, there exists a tendency for visible light transmittance | permeability to fall easily. Further, considering that the handleability deteriorates if the film is too thin, the thickness of the plastic film is preferably 5 to 500 μm, and more preferably 50 to 200 μm.

The surface on which the metal pattern layer is provided on the substrate preferably has adhesiveness. For this purpose, the substrate itself may have the necessary adhesiveness, but it is preferable to laminate an adhesive layer.
The adhesive layer is preferably one having adhesiveness when transferring the metal pattern layer, or one exhibiting adhesiveness under heating or pressurization. As the material having adhesiveness, a resin having a glass transition temperature of 20 ° C. or lower as a main component of the adhesive layer is preferable, and a resin having a glass transition temperature of 0 ° C. or lower is more preferable. As a material used for the adhesive layer, a thermoplastic resin, a thermosetting resin, a resin that is cured by irradiation with active energy rays, or the like can be used. If it shows adhesiveness when heated, if the temperature at that time is too high, the transparent base material may be deformed such as swell, sag, curl, etc., so irradiation with thermoplastic resin, thermosetting resin, active energy rays It is preferable that the glass transition point of the resin that is cured at 80 ° C. or less. The thermoplastic resin, thermosetting resin, and resin cured by irradiation with active energy rays preferably have a weight average molecular weight of 500 or more. If the molecular weight is less than 500, the cohesive strength of the resin is too low, and the adhesion to the metal may be reduced.

  For those having adhesiveness or those showing adhesiveness (hereinafter referred to as “adhesive”), a crosslinking agent, a curing agent, a diluent, a plasticizer, an antioxidant, You may mix | blend additives, such as a filler, a coloring agent, a ultraviolet absorber, and a tackifier.

If the thickness of the adhesive layer is too thin, sufficient strength cannot be obtained. Therefore, when transferring the metal pattern layer formed by plating, the metal pattern layer does not adhere to the adhesive layer, resulting in transfer failure. There is. Accordingly, the thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, and more preferably 3 μm or more in order to ensure transfer reliability during mass production. In addition, if the thickness of the adhesive layer is large, the manufacturing cost of the adhesive layer increases, and the amount of deformation of the adhesive layer increases when laminated, so the thickness of the adhesive layer is preferably 30 μm or less, more preferably 15 μm or less. preferable. When attaching a film with an adhesive having an adhesive layer formed by applying an adhesive to another base film to the surface on which the metal pattern layer is formed, depending on the properties of the adhesive, if necessary If heated.
In addition, in order to improve light diffusibility, a high refractive index nano-sized particle may be added to a film, an adhesive, or the like as a transparent substrate. Examples of such materials include titanium oxide, cerium oxide, and zirconium oxide.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
(Example)
As the metal pattern layer as shown in FIG. 1A, a grid-like (mesh) copper pattern having a pattern width of 5 μm, a thickness of 5 μm, and a distance between patterns of 70 μm was formed. The variation in pattern thickness at that time was ± 1 μm. The pattern was formed by a pattern plating method (prepared with a diamond-like carbon insulating resist in the openings of the SUS plate in a lattice shape so that the underlying metal plate grid was exposed, and then the copper The metal plate was formed to have a metal thickness of 35 μm where the underlying metal plate was exposed by electrolytic plating).

  This grid-like copper pattern was affixed to a polyethylene terephthalate film (film thickness 38 μm) coated with 10 μm of transparent adhesive, and the grid-like copper pattern was peeled off from the SUS plate so as to adhere to the adhesive layer side and transferred. The lattice pattern was embedded in the adhesive and the surface was flattened. And the adhesive layer side in which the grid | lattice-like copper pattern of this film was transcribe | transferred was affixed on soda glass. The transmittance of this transparent heat radiating member was 80%. An image was taken on this sample with a projector, and after 30 minutes, the temperature of the sample was measured and found to be 35 ° C. In addition, the temperature of the sample before taking an image was 25 degreeC which is the same as room temperature.

(Comparative example)
The temperature of the sample was measured in the same manner as in the example except that the metal pattern layer was not provided. The transmittance of this sample was 86%. The temperature of the sample was 55 ° C., and it was confirmed that the transparent heat radiating member of the present invention can suppress an increase in temperature without greatly reducing the transmittance.

Claims (4)

  A transparent heat radiating member provided with at least one or more continuous metal pattern layers on at least one side of a transparent substrate.   The transparent heat radiating member according to claim 1, wherein the metal pattern layers having a continuous shape are arranged in a mesh shape.   The transparent heat radiating member according to claim 1 or 2, wherein the metal pattern layer having a continuous shape is a metal pattern layer having a plurality of openings, and the opening shape is an ellipse.   The transparent heat radiating member according to any one of claims 1 to 3, wherein the metal pattern layer having a continuous shape is formed by a pattern plating transfer method.

Images