Graphite sheet, manufacturing method thereof and reading method thereof

Abstract

The present disclosure addresses the problem of providing a novel graphite sheet provided with identification information and capable of improving readability. A graphite sheet 1 provided with identification information 2 has a first surface S1 which is one surface, and a second surface S2 opposite to the first surface S1. The identification information 2 is composed of an identification part 2A and a non-identification part 2B provided on the first surface S1 of the graphite sheet 1. The thickness d1 of the graphite sheet 1 in the identification part 2A is smaller than the thickness d2 of the graphite sheet 1 in the non-identification part 2B.

Description

Graphite sheet, its manufacturing method and its reading method

[0001] The present disclosure relates to a graphite sheet, a method for manufacturing the graphite sheet, and a method for reading the graphite sheet, and more particularly to a graphite sheet having identification information attached thereto, a method for manufacturing the same, and a method for reading the same.

[0002] In various industrial products, product identification information is marked to indicate the product's lot number or to manage the production and distribution history. The marking is required to have good readability, such that the attached identification information can be read by a reader or the like. Various methods of marking are being considered, such as pasting, printing, engraving, and combinations of these.

[0003] Patent Document 1 discloses a method for producing tablets with clear markings. In this method, a substance with a different color tone from the concave markings is applied to the convex markings of a tablet with markings, and then the tablet is coated as necessary to make the markings clearer.

[0004] Graphite sheets are used in industrial production as heat-conducting sheets, etc. There is also a demand for improved readability of the identification information attached to such graphite sheets.

[0005] Japanese Unexamined Patent Publication No. 58-192819

[0006] An object of the present disclosure is to provide a novel graphite sheet having identification information attached thereto, which can improve readability, a method for manufacturing this graphite sheet, and a method for reading this graphite sheet.

[0007] A graphite sheet according to one aspect of the present disclosure is a graphite sheet having identification information attached thereto, the graphite sheet having a first surface that is one side thereof and a second surface opposite to the first surface, the identification information being composed of an identification portion and a non-identification portion provided on the first surface of the graphite sheet, and the thickness of the graphite sheet at the identification portion being smaller than the thickness of the graphite sheet at the non-identification portion.

[0008] A method for manufacturing a graphite sheet according to one aspect of the present disclosure is a method for manufacturing a graphite sheet having identification information attached thereto, and includes the steps of: preparing a graphite sheet substrate having a first surface and a second surface opposite to the first surface; and applying pressure from the second surface of the graphite sheet substrate to provide an identification portion on the first surface.

[0009] A method for reading a graphite sheet according to one aspect of the present disclosure is a method for reading a graphite sheet having identification information attached thereto, wherein the graphite sheet has an identification portion on a first surface thereof as the identification information, and the method includes a step of reading the identification information of the identification portion from the first surface side of the graphite sheet.

[0010] Fig. 1 is a schematic cross-sectional view showing a portion of a graphite sheet according to a first embodiment of the present disclosure. Fig. 2 is a schematic cross-sectional view showing a portion of a graphite sheet according to a second embodiment of the present disclosure. Fig. 3 is a schematic cross-sectional view showing a method for producing a graphite sheet according to the present disclosure. Fig. 4 is an image obtained by reading identification information attached to a graphite sheet according to the present disclosure.

[0011] Hereinafter, a graphite sheet provided with identification information according to the present embodiment (hereinafter also referred to as graphite sheet 1), a method for manufacturing graphite sheet 1, and a method for reading graphite sheet 1 will be described with reference to the drawings. However, each diagram described in the following embodiments is a schematic diagram, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Note that the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0012] 1 and 2 are schematic cross-sectional views showing a portion of graphite sheet 1, mainly showing a portion bearing identification information 2. Graphite sheet 1 has one surface, a first surface S1, and a second surface S2 opposite to first surface S1.

[0013] Identification information 2 is attached to graphite sheet 1. Specifically, identification information 2 is formed so as to be present on first surface S1 of graphite sheet 1. Identification information 2 is composed of identification portion 2A and non-identification portion 2B provided on first surface S1 of graphite sheet 1. Thickness d1 of the graphite sheet in identification portion 2A is smaller than thickness d2 of the graphite sheet in non-identification portion 2B.

[0014] That is, graphite sheet 1 bearing identification information 2 has, on first surface S1, non-identifiable portion 2B, which corresponds to graphite sheet 1 with a thickness d2, and identification portion 2A, which corresponds to graphite sheet 1 with a thickness d1 that is smaller than d2, and identification portion 2A and non-identifiable portion 2B that constitute identification information 2 are distinguished by the thicknesses d1 and d2 of graphite sheet 1 in each portion.

[0015] Examples of the identification information 2 include one-dimensional codes, two-dimensional codes, character information, symbols, alignment marks, etc. Such identification information 2 is usually composed of a plurality of identification parts 2A and a plurality of non-identification parts 2B.

[0016] Graphite sheet 1 is novel as a graphite sheet 1 bearing identification information 2, and can improve readability. That is, identification information 2 affixed to graphite sheet 1 can be read well. The reason why graphite sheet 1 having the above configuration achieves the above effects can be inferred, for example, as follows. In graphite sheet 1, the thickness of identification portion 2A is smaller than that of non-identification portion 2B (d1<d2). In other words, identification portion 2A and non-identification portion 2B are formed due to the unevenness of graphite sheet 1. As a result, a difference in smoothness occurs on first surface S1 between identification portion 2A and non-identification portion 2B, resulting in a difference in the state of light reflection. Specifically, identification portion 2A corresponding to the recessed portion is smoother, which reduces diffuse reflection of light and makes it appear darker. In this way, a difference in brightness occurs between identification portion 2A and non-identification portion 2B. As a result, it is thought that it becomes easier to distinguish between the identification portion 2A and the non-identification portion 2B that make up the identification information 2, and the readability of the identification information 2 can be improved.

[0017] Thus, the present disclosure can provide a novel graphite sheet bearing identification information that can improve readability, a method for manufacturing this graphite sheet, and a method for reading this graphite sheet.

[0018] 2. Details <Graphite Sheet> [First Embodiment] A portion of graphite sheet 1 according to the first embodiment bearing identification information 2 is shown in Fig. 1. Graphite sheet 1 according to the first embodiment has identification information 2, which constitutes identification portion 2A and non-identification portion 2B, bearing first surface S1, and thickness d1 of graphite sheet 1 in identification portion 2A being smaller than thickness d2 of graphite sheet 1 in non-identification portion 2B.

[0019] When graphite sheet 1 has three or more regions with different thicknesses d, the regions with thicknesses greater than the arithmetic mean value dm of thicknesses d are designated as non-identifiable portions 2B, and the regions with thicknesses equal to or less than the arithmetic mean value dm are designated as distinguishable portions 2A.

[0020] The "thickness" of identified portion 2A, represented by d1, and the "thickness" of non-identifiable portion 2B, represented by d2, refer to the "average thickness" which is the arithmetic mean value of measurements taken at multiple points (e.g., any 10 points) in identified portion 2A or non-identifiable portion 2B of graphite sheet 1.

[0021] Graphite sheet 1 typically has a plurality of identification portions 2A and a plurality of non-identification portions 2B. The plurality of d1s may be the same or different, and the plurality of d2s may be the same or different, but it is preferable that the plurality of d1s and the plurality of d2s are the same.

[0022] In graphite sheet 1, for example, the portion of second surface S2 facing identification portion 2A on first surface S1 is recessed. That is, in graphite sheet 1, the region of second surface S2 opposite to the region of identification portion 2A on first surface S1 typically forms a recess. Such graphite sheet 1 can be easily manufactured by imprinting with a stamp, for example. The portion of first surface S1 facing non-identification portion 2B on second surface S2 of graphite sheet 1 may be flat, protruding, or recessed, but is typically flat, as long as thickness d2 of graphite sheet 1 in non-identification portion 2B is greater than thickness d1 in identification portion 2A.

[0023] "Graphite sheet" refers to a sheet whose main component is graphite. "Graphite" is a type of carbon allotrope, and is also called graphite. Graphite is a material in which carbon atoms are sp ２ The graphene layer is a hexagonal honeycomb lattice-shaped layer (graphene layer) bonded together in the thickness direction by van der Waals forces. The term "major component" refers to the component with the highest content, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 99% by mass or more. The term "sheet" refers to a generally flat molded body whose thickness is small relative to its length and width.

[0024] Graphite sheet 1 has, for example, a rectangular shape in plan view. The length and width of graphite sheet 1 are not particularly limited, but may be, for example, 1 cm to 1 m in length and 1 cm to 30 cm in width. Graphite sheet 1 has, for example, an average thickness of 1 μm to 5 mm, and preferably 10 μm to 1 mm in average.

[0025] Graphite sheet 1 preferably has a dimension d1 of 0.2 μm or more and 4 mm or less, more preferably 2 μm or more and 1 mm or less, and even more preferably 10 μm or more and 100 μm or less.

[0026] Graphite sheet 1 preferably has a dimension d2 of 1 μm or more and 5 mm or less, more preferably 10 μm or more and 1 mm or less, and even more preferably 50 μm or more and 200 μm or less.

[0027] When d1 and d2 are within the above ranges, the readability of graphite sheet 1 can be further improved.

[0028] The lower limit of the ratio of d1 to d2 (d1 / d2) in graphite sheet 1 is preferably 0.05 or more, more preferably 0.15 or more, even more preferably 0.5 or more, and particularly preferably 0.8 or more. The upper limit of d1 / d2 is, for example, 0.98 or less, preferably 0.95 or less. By setting d1 / d2 within the above range, better contrast can be achieved between identification portion 2A and non-identification portion 2B.

[0029] Graphite sheet 1 of the first embodiment can be produced by, for example, placing a graphite sheet substrate not bearing identification information 2 on a stand such as aluminum block 20, and applying pressure to stamp the graphite sheet substrate with stamp 10, the underside of which has a plurality of recesses corresponding to identification information 2, as shown in FIG. 3 , thereby applying identification information 2.

[0030] Thus, when graphite sheet 1 is produced from a single graphite sheet substrate, the identification portion 2A and the non-identification portion 2B of graphite sheet 1 are made of the same material. That is, typically, both the identification portion 2A and the non-identification portion 2B of graphite sheet 1 are made of graphite. Such graphite sheet 1 can be easily produced. "Made of the same material" means that the identification portion 2A and the non-identification portion 2B of graphite sheet 1 do not contain any components other than graphite, or, if they contain other components, the types and concentrations of the other components are the same.

[0031] Second Embodiment FIG. 2 shows a portion of graphite sheet 1 according to a second embodiment, on which identification information 2 is provided.

[0032] Graphite sheet 1 of the second embodiment has a basic configuration in common with graphite sheet 1 of the first embodiment, and differs only in that a transparent film 3 is attached to first surface S1. In graphite sheet 1 of the second embodiment, components common to graphite sheet 1 of the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0033] Graphite sheet 1 of the second embodiment has transparent film 3 attached to first surface S1. Because transparent film 3 is attached to first surface S1, graphite sheet 1 of the second embodiment can achieve improved readability compared to graphite sheet 1 of the first embodiment. This is because, for example, transparent film 3 fills in any irregularities on first surface S1 of graphite sheet 1, further improving the smoothness of first surface S1 and increasing the difference in brightness between identification portion 2A and non-identification portion 2B. This may result in easier discrimination between identification portion 2A and non-identification portion 2B, among other reasons.

[0034] The term "transparent film" refers to a film-shaped object having a light transmittance of 80% or more for light in the visible light range. The transparent film 3 may be an adhesive tape containing an adhesive on one side, or a heat-sealable tape. Examples of the transparent film 3 include polyethylene terephthalate (PET) film.

[0035] The average thickness of transparent film 3 is preferably 1 μm or more and 1 mm or less, and more preferably 5 μm or more and 500 μm or less. By setting the average thickness of transparent film 3 within the above range, the readability of graphite sheet 1 can be further improved.

[0036] Transparent film 3 may be attached to the area of ​​first surface S1 where identification information 2 is provided, or may be attached to the entire first surface S1 of graphite sheet 1.

[0037] Graphite sheet 1 of the second embodiment can be manufactured in the same manner as in the above-described first embodiment, for example, by placing a graphite sheet substrate having transparent film 3 attached to first surface S1 on a stand such as aluminum block 20, and applying pressure to stamp 10 having a plurality of recesses formed on the underside thereof corresponding to identification information 2, thereby affixing identification information 2 to the graphite sheet substrate.

[0038] <Graphite Sheet Manufacturing Method> Graphite sheet 1 can be simply and reliably manufactured by a manufacturing method including, for example, a step of preparing a graphite sheet substrate (hereinafter also referred to as a preparation step) and a step of applying pressure from second surface S2 of the graphite sheet substrate to provide identification portion 2A on first surface S1 (hereinafter also referred to as a pressure application step).

[0039] [Preparation Step] In this step, a graphite sheet substrate is prepared. The graphite sheet substrate has a first surface S1 and a second surface S2. The "graphite sheet substrate" refers to a graphite sheet to which no identification information 2 is attached.

[0040] When manufacturing graphite sheet 1 of the second embodiment, in this step, a graphite sheet substrate having transparent film 3 attached to first surface S1 is prepared.

[0041] [Pressure Application Step] In this step, pressure is applied from the second surface S2 of the graphite sheet substrate to provide the identification portion 2A on the first surface S1.

[0042] Specifically, as shown in FIG. 3 , a method for applying pressure from second surface S2 of the graphite sheet substrate may include placing the graphite sheet substrate or the graphite sheet substrate having transparent film 3 attached to first surface S1 on a stand such as aluminum block 20, and pressing the graphite sheet substrate with stamp 10 made of a metal such as aluminum and having a plurality of recesses formed on the underside thereof corresponding to identification information 2.

[0043] This manufacturing method provides graphite sheet 1 having identification portion 2A on first surface S1, non-identification portion 2B in the area other than identification portion 2A, and a recess in the area facing identification portion 2A on second surface S2.

[0044] <Graphite Sheet Reading Method> Identification information 2 in graphite sheet 1 bearing identification information 2 can be read simply and reliably by a graphite sheet reading method that includes a step of reading identification information 2 in identification section 2A from the first surface S1 side of graphite sheet 1 (hereinafter also referred to as the reading step), for example.

[0045] [Reading Step] In this step, identification information 2 in identification portion 2A is read from first surface S1 of graphite sheet 1. In this step, graphite sheet 1 having identification portion 2A provided on first surface S1 as identification information 2 is used.

[0046] Graphite sheet 1 of this embodiment has identification portion 2A on first surface S1 as identification information 2, and as described above, a difference in brightness occurs between identification portion 2A and non-identification portion 2B, improving the readability of identification information 2. Therefore, by reading from the first surface S1 side of graphite sheet 1, identification information 2 can be read more easily than when reading from the second surface S2 side.

[0047] In the reading step, examples of the method for reading the identification information 2 include a method using a reading device such as a smartphone or a barcode reader, a method of obtaining the information as a photograph or image, and a method of recognizing the information with the naked eye.

[0048] When reading graphite sheet 1 of the second embodiment, a graphite sheet substrate having transparent film 3 attached to first surface S1 is used in this process. Fig. 4 shows an image obtained by reading graphite sheet 1 of the second embodiment, having a two-dimensional code attached as identification information 2 and transparent film 3 attached to first surface S1, from the first surface S1 side. By using graphite sheet 1 of the second embodiment having transparent film 3 attached to first surface S1 as graphite sheet 1, reading becomes more reliable than when graphite sheet 1 of the first embodiment is used.

[0049] (Summary) As is clear from the above embodiment, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiment.

[0050] The graphite sheet (1) of the first embodiment is a graphite sheet (1) bearing identification information (2). The graphite sheet (1) has a first surface (S1) that is one surface, and a second surface (S2) opposite the first surface (S1). The identification information (2) is composed of an identification portion (2A) and a non-identification portion (2B) provided on the first surface (S1) of the graphite sheet (1). The thickness (d1) of the graphite sheet (1) in the identification portion (2A) is smaller than the thickness (d2) of the graphite sheet (1) in the non-identification portion (2B).

[0051] According to the first aspect, the graphite sheet (1) is novel as a graphite sheet (1) having identification information (2) attached thereto, and the graphite sheet (1) can improve the readability of the identification information (2).

[0052] In the graphite sheet (1) of the second embodiment, in the first embodiment, the second surface (S2) has a recess in a portion facing the identification portion (2A) of the first surface (S1).

[0053] According to the second aspect, the graphite sheet (1) can be produced more easily.

[0054] In the graphite sheet (1) of the third embodiment, the portion in the identification portion (2A) and the portion in the non-identification portion (2B) of the graphite sheet (1) in the first or second embodiment are made of the same material.

[0055] According to the third aspect, the graphite sheet (1) can be produced more easily.

[0056] In the graphite sheet (1) of the fourth embodiment, in any one of the first to third embodiments, a transparent film is attached to the first surface (S1).

[0057] According to the fourth aspect, the graphite sheet (1) can further improve the readability of the identification information (2).

[0058] A fifth aspect of the method for producing a graphite sheet (1) is a method for producing a graphite sheet bearing identification information, and includes a preparation step and a pressure application step. In the preparation step, a graphite sheet substrate having a first surface (S1) and a second surface (S2) opposite to the first surface (S1) is prepared. In the pressure application step, pressure is applied from the second surface (S2) of the graphite sheet substrate to provide an identification portion (2A) on the first surface (S1).

[0059] According to the fifth aspect, the graphite sheet (1) can be produced simply and reliably.

[0060] In the sixth aspect of the method for producing a graphite sheet (1), in the fifth aspect, a graphite sheet substrate having a transparent film (3) attached to a first surface (S1) is prepared in the preparation step.

[0061] According to the sixth aspect, a graphite sheet (1) with improved readability can be produced.

[0062] A seventh aspect of the method for reading a graphite sheet (1) is a method for reading a graphite sheet (1) bearing identification information (2). The graphite sheet (1) has an identification section (2A) on its first surface (S1) as the identification information (2). The method includes a step of reading the identification information (2) in the identification section (2A) from the first surface (S1) of the graphite sheet (1).

[0063] According to the seventh aspect, the identification information (2) attached to the graphite sheet (1) can be read easily and reliably.

[0064] In the eighth aspect of the method for reading a graphite sheet (1), the graphite sheet (1) used in the seventh aspect has a transparent film (3) attached to its first surface (S1).

[0065] According to the eighth aspect, it is possible to read the identification information (2) attached to the graphite sheet (1) more reliably.

[0066] 1 Graphite sheet S1 First surface S2 Second surface 2 Identification information 2A Identification section 2B Non-identification section d1 Thickness of graphite sheet in identification section d2 Thickness of graphite sheet in non-identification section 3 Transparent film

Claims

1. A graphite sheet bearing identification information, wherein the graphite sheet has a first surface that is one side of the graphite sheet and a second surface opposite the first surface, the identification information is composed of an identification portion and a non-identification portion provided on the first surface of the graphite sheet, and the thickness of the graphite sheet at the identification portion is smaller than the thickness of the graphite sheet at the non-identification portion.

2. The graphite sheet according to claim 1, wherein the second surface has a recessed portion facing the identification portion on the first surface.

3. The graphite sheet according to claim 1 or 2, wherein the distinguishable portion and the non-distinguishable portion of the graphite sheet are made of the same material.

4. The graphite sheet according to claim 1 or 2, wherein a transparent film is attached to the first surface.

5. A method for manufacturing a graphite sheet bearing identification information, comprising the steps of: preparing a graphite sheet substrate having a first surface and a second surface opposite to the first surface; and applying pressure from the second surface of the graphite sheet substrate to provide an identification portion on the first surface.

6. The method for producing a graphite sheet according to claim 5, wherein in the preparation step, a graphite sheet substrate having a transparent film attached to the first surface is prepared.

7. A method for reading a graphite sheet bearing identification information, wherein the graphite sheet has an identification section on a first surface thereof as the identification information, the method comprising the step of reading the identification information of the identification section from the first surface side of the graphite sheet.

8. The graphite sheet reading method according to claim 7, wherein the graphite sheet has a transparent film attached to the first surface.

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