JP7463661B2 - Information display and manufacturing method thereof - Google Patents

Description

The present invention relates to an information display formed from a solid material and a method for manufacturing the same.

Conventionally, technologies have been used to attach barcodes to various products for product management, and to attach QR codes to advertisements, pamphlets, flyers, etc. to provide information.

In recent years, for example, Patent Document 1 discloses technology relating to a concrete product that is composed of cement and aggregate that has a different contrast from the cement, and in which information patterns such as two-dimensional codes are formed on the surface by exposing the aggregate on the surface. Patent Document 2 discloses technology for providing a two-dimensional code on the formwork of a block and transferring it to the surface of the concrete.

JP 2013-176923 A JP 2014-031638 A

However, in Patent Document 1, in order to create unevenness in the hardened body itself, different materials (aggregates with different contrasts) are embedded in the areas of information patterns such as two-dimensional codes, which is time-consuming. In addition, in Patent Document 2, multiple formwork is used to provide the surface layer blocks, which is not only time-consuming to form, but also makes it difficult to maintain the integrity of the formed surface layer blocks.

The present invention was made in consideration of these circumstances, and aims to provide an information display device that forms a concave-convex shape that indicates specific information on the information display section, making it possible to read the specific information from the shadows of the concave-convex shapes that are formed.

(1) In order to achieve the above object, the present invention takes the following measures. That is, the information display of the present invention is an information display formed of a solid material, and has an information display section provided with multiple recesses and protrusions, and the recesses and protrusions are provided alternately or continuously in one or two directions on the information display section to represent specific information, and the specific information can be read from the shadows created by adjacent recesses and protrusions. This makes it possible to directly apply specific information to the information display. Also, by forming multiple recesses and protrusions representing specific information in two directions, a two-dimensional code can be formed, making it possible to provide more information.

(2) In addition, the information display of the present invention is characterized in that the inclined surface between the bottom surface of the recess and the top surface of the protrusion is inclined at a right angle or an acute angle to the information display section. This makes it possible for a reading device to accurately recognize the information displayed on the information display section.

(3) Furthermore, in the information display of the present invention, when the width of the upper surface of the convex portion or the open end of the concave portion is l and the height of each of the convex portions or the depth of each of the concave portions is d, the aspect ratio calculated as d/l is 0.5 or more. This enables a reading device to accurately recognize the information displayed on the information display portion.

(4) Furthermore, in the information display of the present invention, the material is cement paste, mortar, or concrete. This makes it possible to install the information display directly on the wall surface of a structure or the slope of a road, and as a result, it becomes possible to provide information about the structure, road information, tourist information, etc.

(5) In addition, in the information display of the present invention, the information display portion is formed by vertically stacking a powdered hydraulic composition solidified by spraying an aqueous hardening agent onto the powdered hydraulic composition. This makes it possible to easily form the information display portion even if the shape of the information display portion is complex.

(6) In addition, in the information display of the present invention, the information display portion is formed by filling a formwork in which the three-dimensional shape of the information display portion has been formed in advance with a cement mixture made by mixing cement and water, or cement, water, and aggregate, allowing it to harden, and then removing the formwork. This makes it possible to easily form an information display portion with unevenness.

(7) In addition, the information display of the present invention is characterized in that the maximum particle size of the aggregate is equal to or smaller than the minimum width of the information display portion. This makes it possible to fill the formwork with the cement mixture without creating voids in the fine details inside the formwork.

(8) In addition, in the information display of the present invention, the information display portion is formed by cutting the hardened cement body. This makes it possible to form an information display with unevenness on a large hardened cement body.

(9) In addition, the information display of the present invention is characterized in that the maximum particle size of the aggregate in the hardened cement body is 5 mm or less. This makes it possible to prevent defects due to aggregate pop-out caused by peeling at the interface between the aggregate and the paste during cutting.

(10) The method for manufacturing an information display of the present invention is a method for manufacturing an information display formed of a solid material, and includes a step of providing a plurality of recesses and protrusions on the information display, and the recesses and protrusions are provided alternately or continuously on the information display in one or two directions to represent specific information, the inclined surface between the bottom surface of the recess and the upper surface of the protrusion is inclined at a right angle or an acute angle to the information display, and the aspect ratio calculated by d/l is 0.5 or more, where l is the width of the upper surface of each protrusion or the opening end of each recess, and d is the height of each protrusion or the depth of each recess. This makes it possible to directly apply specific information to the information display. Also, by forming a plurality of recesses and protrusions representing specific information in two directions, a two-dimensional code can be formed, making it possible to provide more information.

According to the present invention, it is possible to provide an information display device that carries specific information that can be read from the shadows created by the concave and convex parts. As a result, for example, when an information display device is provided on the wall surface of a building or the like, it is possible to provide information such as the date of manufacture, the place of manufacture, and the materials used. Also, when an information display device is provided on the slope of a road, it is possible to provide information such as road information and tourist information.

FIG. 2 is a front view of the information display body according to the present embodiment. 1 is a perspective view of an information display according to an embodiment of the present invention; FIG. 2 is a schematic diagram of an information display according to the present embodiment. FIG. 2 is a diagram showing a part of a cross section of an information display according to the embodiment. 2 is a flow chart showing a procedure for producing a hardened cement body. FIG. 1 is a diagram showing an outline of the procedure for producing a hardened cement body by layering using an additive manufacturing device. FIG. 13 is a diagram showing an information display used in this verification. FIG. 13 is a diagram showing an information display used in this verification. FIG. 13 is a diagram showing an information display used in this verification. 13A and 13B are diagrams illustrating modified examples of the information display body according to the embodiment. FIG. 8B is a diagram showing the information display 200 of FIG. 8A as viewed from the longitudinal direction.

The inventors noticed that a large amount of information can be provided by adding code information to an information display made of a solid material, and discovered that the specific information can be read by providing the information display with multiple recesses and protrusions that represent specific information and creating shadows using the recesses and protrusions, thus arriving at the present invention.

In other words, the information display of the present invention is an information display formed of a solid material, and is characterized in that it comprises an information display section having a plurality of recesses and protrusions, and that the recesses and protrusions are arranged alternately or continuously in one or two directions on the information display section to display specific information, and that the specific information can be read from the shadows created by adjacent recesses and protrusions. In this way, the inventors have made it possible to attach information to the information display section. The present embodiment will be described below with reference to the drawings.

[1. Configuration of information display body]
FIG. 1A is a front view of the information display according to the present embodiment. FIG. 1B is a perspective view of the information display according to the present embodiment. The information display 100 shown in FIG. 1A and FIG. 1B includes an information display section 11 having a plurality of recesses and protrusions representing specific information on the main plane of the information display 100. The recesses 21 and protrusions 31 on the information display section 11 are alternately or continuously provided in two directions on the main plane of the information display 100, forming a two-dimensional code having a structure in which squares or dots are arranged in a lattice pattern. In this way, the user can obtain the information attached to the two-dimensional code by reading the code formed on the information display section 11 with a reading device such as a two-dimensional code reader.

The information display 100 shown in Figures 1A and 1B is 10 cm x 10 cm x 1.0 cm (cell count 33 x 33), the length (width) l of the top surface of each convex portion or the open end of each concave portion is 2 mm, and the height of each convex portion or the depth d of each concave portion is 3 mm.

Figure 2 is a schematic diagram of an information display according to this embodiment. The reading device performs binarization processing on the image of the two-dimensional code captured by the device itself, and extracts and recognizes the code including the dimensions and information of the reading area shown in Figure 2. However, if the code cannot be correctly recognized in the binarized image from the captured image, the code cannot be correctly read. In other words, in order for the reading device to obtain information as a two-dimensional code, it is necessary for the reading device to recognize the uneven parts (concave and convex parts) that correspond to the cell parts of the two-dimensional code. In this embodiment, the cells are distinguished by creating shadows using adjacent concave and convex parts 21 and convex parts 31.

3 is a diagram showing a part of a cross section of the information display 100 according to this embodiment. The cross section of the information display 100 shown in FIG. 3 is a cross section of the information display 100 produced by a layered three-dimensional modeling device (details of the production method will be described later), so the inclined surface 45 between the bottom surface 23 of the recess 21 and the top surface 33 of the protrusion 31 is stepped, but is not limited to this. For example, the inclined surface 45 between the bottom surface 23 of the recess 21 and the top surface 33 of the protrusion 31 may be linear. In order to create shadows with an uneven shape, as shown in FIG. 3, it is preferable that the inclined surface 45 between the bottom surface of the recess and the top surface of the protrusion is inclined at a right angle or an acute angle (θ is 90° or less) with respect to the main plane of the information display.

In addition, if the length (width) of the top surface of a convex portion or the open end of a concave portion, which corresponds to the length (width) of the smallest unit (one cell) of a two-dimensional code, is l, and the height of each convex portion or the depth of each concave portion is d, then the aspect ratio calculated as d/l is preferably 0.5 or greater. To create clearer shading, the aspect ratio (d/l) is more preferably 1.0 or greater, and even more preferably 2.0 or greater. Details of the aspect ratio (d/l) will be described later.

In this embodiment, a QR code, which is an example of a matrix type two-dimensional code, has been used for explanation, but the present invention is not limited to this. For example, a barcode represented as a one-dimensional code, a stack type two-dimensional code, or a matrix type two-dimensional code other than a QR code may be used.

[2. Manufacturing method of information display body having uneven surface]
A method for manufacturing an information display body according to this embodiment will be described. The manufacturing method includes a manufacturing method using a layered three-dimensional modeling device (additive manufacturing device/3D printer), a manufacturing method using a formwork, and a manufacturing method using cutting. Each method will be described below. Note that, although a cement hardened body will be used as an example of the information display body according to this embodiment, the present invention is not limited to this.

(1) Manufacturing method using a layered three-dimensional modeling device (additive manufacturing device/3D printer) Figure 4 is a flow chart showing the manufacturing procedure for an information display body with a concave-convex shape (hereinafter, referred to as a hardened cement body). First, 3D model data of the hardened cement body with concave and convex parts is created (step S1). Next, the created 3D model data is converted into 3D data for output (step S2). The converted 3D data for output is divided into a number of horizontal planes (step S3). Next, the shapes of the divided horizontal planes are layered in sequence using an additive manufacturing device (step S4).

The work of step S4 will be described in detail. Figure 5 is a diagram showing an outline of the procedure for manufacturing a hardened body by layering using an additive manufacturing device. Here, inorganic powder that can be used with an additive 3D modeling device is used as the material. The details of the inorganic powder material are that the material for the hydraulic composition described below is mixed mechanically or manually, or mixed and crushed in a crusher, and adjusted.

First, the powder feeder 51 flattens the inorganic powder placed on the table (FIG. 5(a)). Next, based on the data of the shape of the divided horizontal surface, the head 55 sprays the aqueous hardener to solidify the powder (FIG. 5(b)). After completing step T2, the table 57 is lowered one level, the powder supply tank 59 is raised one level, and the inorganic powder is spread on the table 57 (FIG. 5(c)). By repeating the steps from FIG. 5(a) to FIG. 5(c) and removing the excess powder from the molded object 61 formed by stacking the shape of the divided horizontal surface, a cement hardened body with an uneven shape can be manufactured (FIG. 5(d)). In this way, in the manufacturing method using the layered three-dimensional modeling device, the cement hardened body is formed based on 3D data as described above, so it is possible to create complex shapes.

The produced hardened cement body can be cured in air alone, cured in air followed by underwater curing, cured with a surface impregnating agent, or cured with steam. Of these, air curing alone is preferred for the hardened cement body according to this embodiment. The details of the materials will be described later, but from the viewpoint of strength enhancement by calcium aluminate, fast-hardening cement, and polyvinyl alcohol contained in the hydraulic composition, the temperature for air curing is preferably 10 to 100°C, and more preferably 30 to 80°C. From the viewpoint of sufficient strength development and production efficiency, the relative humidity for air curing is preferably 10 to 90%, more preferably 15 to 80%, and even more preferably 20 to 60%. From the viewpoint of sufficient strength development and production efficiency, the air curing period is preferably 1 hour to 1 week, more preferably 2 hours to 5 days, and even more preferably 3 hours to 4 days.

(Hydraulic Composition)
The hydraulic composition used in the present embodiment is required to have a certain degree of strength because if it is too soft, the model will collapse during processing, etc. The hydraulic composition used in the case of performing latent image processing on a hardened cement body using a layered three-dimensional modeling device will be described.

The hydraulic composition contains 100 parts by weight of inorganic binder, 2 to 12 parts by weight of polyvinyl alcohol, and 28 to 130 parts by weight of water and sand for a total weight of 100 parts by weight of composite binder.

The inorganic binder contains one or more selected from calcium aluminates as essential components, and further contains gypsum and rapid hardening cement as optional components. Among inorganic binders, calcium aluminate has high strength development, and is therefore preferred for use as an inorganic binder, and it is particularly preferred to use amorphous calcium aluminate. In particular, amorphous calcium aluminate does not have a substantial crystalline structure because it is produced by melting the raw materials and then rapidly cooling them, and its vitrification rate is usually 80% or more. The higher the vitrification rate, the higher the early strength development, so the vitrification rate is preferably 90% or more.

To further improve early strength development, the inorganic binder may contain gypsum as an optional component. The gypsum may be one or more types selected from anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, with hemihydrate gypsum being preferred since it has higher early strength development.

In order to further improve early strength development, the inorganic binder may contain a rapid-hardening cement (also called ultra-rapid-hardening cement) as an optional component, and the rapid-hardening cement is preferably a rapid-hardening cement (ultra-rapid-hardening cement) that sets within 30 minutes as measured in accordance with JIS R 5210, or a water-stopping cement.

The inorganic binder may contain cement as another component. If the cement has a setting time of 3 hours and 30 minutes or less as measured in accordance with JIS R 5210, it is preferable because the early strength development is high 3 hours after molding, and more preferably within 1 hour. The cement may be one or more of ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, low heat Portland cement, white Portland cement, ecocement, blast furnace cement, fly ash cement, and cement clinker powder. The content of calcium silicate in the cement is preferably 25% by mass or more, assuming that the total cement is 10% by mass. If the content is 25% by mass or more, the strength development is high after 1 day of age, and if long-term strength development is required, the content is preferably 45% by mass or more.

In order to improve early strength development, the cement content in the inorganic binder is preferably 0 to 50% by mass, more preferably 0 to 30% by mass, and even more preferably 0 to 20% by mass, with the total inorganic binder being 100% by mass.

The composite binder is a binder containing 2 to 12 parts by mass of polyvinyl alcohol per 100 parts by mass of inorganic binder. If the blending ratio of polyvinyl alcohol is less than 2 parts by mass, the effect of improving strength is low, and if it exceeds 12 parts by mass, deformation or cracks may occur due to shrinkage of the molded product depending on the shape, making it impossible to manufacture complex shapes. The blending ratio of polyvinyl alcohol is more preferably 2 to 10 parts by mass, and even more preferably 3 to 9 parts by mass, per 100 parts by mass of inorganic binder.

The average particle size (median diameter, D50) of the polyvinyl alcohol is preferably 150 μm or less, more preferably 90 μm or less, and even more preferably 10 to 75 μm or less, since this provides high strength. The content of polyvinyl alcohol particles larger than 94 μm is preferably 90% by mass or less, more preferably 45% by mass or less, and even more preferably 30% by mass or less. The content of polyvinyl alcohol particles larger than 77 μm is preferably 90% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

The hydraulic composition is a composition that contains 28 to 130 parts by mass of water and sand per 100 parts by mass of composite binder. If the mixing ratio of water is within this range, strength development can be ensured. The mixing ratio of sand is preferably 100 to 1500 parts by mass, more preferably 150 to 1200 parts by mass, and even more preferably 200 to 1000 parts by mass per 100 parts by mass of composite binder. If the mixing ratio of sand is within this range, strength development can also be ensured.

As another component of the hydraulic composition, in order to facilitate the process of removing the unhardened powder of the hydraulic composition remaining after molding from the molded product (de-powdering), the hydraulic composition may further contain 0.1 to 2 parts by mass, more preferably 0.5 to 1.5 parts by mass of hydrophobic fumed silica as an optional component per 100 parts by mass of the composite binder in total.

(2) Manufacturing method using a formwork Next, the manufacturing method using a formwork will be described. First, a formwork is prepared in advance with concave and convex parts in the shape to be produced (step P1). Next, a cement mixture made by mixing cement and water, or cement with aggregate such as sand or gravel and water, is filled into the formwork and allowed to harden (step P2). After the cement mixture has hardened, it is removed from the formwork (step P3).

In the present embodiment, the cement hardened body creates shadows with an uneven shape, so that the inclined surface between the bottom surface of the recess and the top surface of the protrusion is preferably inclined at a right angle or an acute angle to the main plane of the information display body. Therefore, if the inclined surfaces at the bottom surface of the recess and the top surface of the protrusion are inclined at an acute angle, it is difficult to remove the form after the cement mixture has hardened in this manufacturing method. Therefore, it is preferable to form the form using a material that melts with heat, such as wax, or a resin with high deformability, and to remove the form after the cement mixture has hardened by dissolving the form or physically deforming the form. In the case of a form having a complex shape with multiple recesses and protrusions, it is more preferable to use a form formed using the above-mentioned layered three-dimensional modeling device.

When producing a hardened cement body using a formwork, if the cement mixture you fill contains a large amount of air, air bubbles will form after hardening, which may cause the surface irregularities to become distorted. For this reason, it is preferable to mix an antifoaming agent into the cement mixture to reduce the amount of air.

In addition, when filling the formwork with the cement mixture, it is preferable that the maximum particle size of the aggregate is equal to or smaller than the minimum width of the concave and convex parts of the hardened cement body to be formed, so that the cement mixture can be filled without creating voids in the formwork. More preferably, it is equal to or smaller than two-thirds of the minimum width, and even more preferably, it is equal to or smaller than one-half of the minimum width.

It is also preferable that the mixture has a suitable viscosity and resistance to material separation, and has a low amount of bleeding, so that bleeding water does not remain in the concave and convex parts of the hardened cement body that is formed.

(3) Manufacturing method by cutting First, a cement hardened body is prepared, and the cement hardened body is cut based on the created 3D model data. There are two types of cutting methods: a cutting method using a machine and a water jet method. In the cutting method using a machine, the hardened mortar is cut using a cutting machine, so that it is possible to form and process recesses and protrusions in a large mortar hardened body. In the cutting method using a water jet method, the hardened cement body is cut using the force of high-pressure water compressed and sprayed by a high-pressure pump, so that it is possible to form and process recesses and protrusions. When using the water jet method, it is possible to suppress vibrations, etc., on the mortar hardened body compared to the cutting method using a machine, so that it is possible to form and process recesses and protrusions while minimizing the impact on the cement hardened body.

When processing by cutting, there is a risk that the aggregate in the hardened cement body will peel off at the interface with the paste, popping out and causing defects. Therefore, it is preferable to use aggregate and paste with similar strengths. In addition, it is preferable to use small aggregate with a maximum particle size of 5 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less. Furthermore, it is preferable to use aggregate with angular edges.

3. Cell aspect ratio
In order for a reading device to obtain information as a two-dimensional code, it is necessary for the reading device to recognize the recesses and protrusions that correspond to the cell parts of the two-dimensional code. In this embodiment, the cells are distinguished by creating shadows between adjacent recesses and protrusions. Therefore, when the width of the top surface of a protrusion or the open end of each recess, which corresponds to the length (width) of the smallest unit (one cell) of a two-dimensional code, is l, and the height of each protrusion or the depth of each recess is d, the aspect ratio represented by d/l must be set to a certain value to enable reading.

Figures 6A, 6B, and 7 are diagrams showing the information display used in this verification. Figures 6A, 6B, and 7 show hardened cement bodies produced using the hydraulic composition described above and a manufacturing method that uses a layered three-dimensional modeling device (additive manufacturing device/3D printer). Each hardened cement body was produced with object dimensions of 100 mm x 100 mm x 10 mm and reading area dimensions of 80 mm x 80 mm x 8 mm (number of cells: 33 pixels x 33 pixels).

The information display shown in Fig. 6A is a hardened cement body with a concave portion formed in the information display portion (hereinafter referred to as a concave-type hardened cement body). The information display shown in Fig. 6B is a hardened cement body with a convex portion formed in the information display portion (hereinafter referred to as a convex-type hardened cement body). The information displays shown in Figs. 7(a) to (c) are concave-type hardened cement bodies made with the depths of each concave portion of the concave-type hardened cement body set to (a) d = 1.0 mm, (b) d = 1.5 mm, and (c) d = 3.0 mm. As can be seen from Figs. 7(a) to (c), the brightness of the shadows varies depending on the depth of each concave portion.

Therefore, five types of concave hardened cement bodies with different depths d of each concave portion were created, and verification was carried out as to whether the codes could be read by a two-dimensional code reader. The results are summarized in Table 1. The length (width) l of one cell, which is the smallest unit formed in the information display section of the hardened cement body used in this verification, was set to 2.4 mm.

From the above verification results, it was found that the aspect ratio (d/l) is preferably 0.5 or more. To create clearer shading, it is more preferable that the aspect ratio (d/l) is 1.0 or more, and even more preferable that it is 2.0 or more.

(Modification)
FIG. 8A is a diagram showing a modified example of the information display body according to the present embodiment. FIG. 8B is a diagram showing the information display body 200 of FIG. 8A as viewed from the longitudinal axis direction. FIG. 8A and FIG. 8B show a cement hardened body 200 produced by a production method using a layered three-dimensional modeling device (additive manufacturing device/3D printer) using the above-mentioned hydraulic composition as a material. The cement hardened body 200 is produced with a model size of 100 mm×200 mm×10 mm and a reading area size of 80 mm×160 mm×10 mm (number of cells: 33 pixels×33 pixels). In the modified example shown in FIG. 8A, the information display body 200 is produced by changing the aspect ratio of the information display portion, that is, the opening end of the recess or the upper surface of the protrusion forming each cell, without changing the number of cells, so that when the information display body 200 is viewed from another angle, it can be recognized as a two-dimensional code as shown in FIG. 8B.

In this way, by changing the aspect ratio of the open ends of the recesses or the top surfaces of the protrusions that form each cell to create an information display, it is possible to provide information such as road information and tourist information on road surfaces or wall surfaces, for example.

As explained above, multiple recesses and protrusions showing specific information are provided on the surface of the hardened cement body, making it possible to read the specific information from the shadows of the recesses and protrusions. As a result, for example, when an information display is provided on the wall of a building, etc., it is possible to provide information such as the manufacturing date, manufacturing location, and materials used, and when an information display is provided on the slope of a road, it is possible to provide information such as road information and tourist information.

100, 200 Information display body (hardened cement body)
REFERENCE SIGNS LIST 11 Information display section 21 Recess 23 Bottom surface 31 Protrusion 33 Top surface 45 Inclined surface 51 Powder feeder 53 Roller 55 Head 57 Table 59 Powder feed tank 61 Model

Claims (10)

An information display formed of a material having solidity,
an information display section provided with a plurality of recesses and protrusions;
The recesses and protrusions are provided alternately or continuously in one or two directions on the information display portion to display specific information;
An information display body, characterized in that the specific information can be read by a shadow created by adjacent concave and convex portions. The information display according to claim 1, characterized in that the inclined surface between the bottom surface of the recess and the top surface of the protrusion is inclined at a right angle or an acute angle to the information display section. The information display according to claim 1 or 2, characterized in that, when the width of the upper surface of the convex portion or the open end of the concave portion is l and the height of each convex portion or the depth of each concave portion is d, the aspect ratio calculated as d/l is 0.5 or more. An information display according to any one of claims 1 to 3, characterized in that the material is cement paste, mortar or concrete. A method for manufacturing an information display formed of a solid material, comprising the steps of:
providing a plurality of recesses and protrusions on the information display portion;
The recesses and protrusions are provided alternately or continuously in one or two directions on the information display portion to display specific information;
an inclined surface between the bottom surface of the recess and the top surface of the protrusion is inclined at a right angle or an acute angle with respect to the information display portion;
A method for manufacturing an information display body, characterized in that, when the width of the upper surface of each of the convex portions or the opening end of each of the concave portions is l and the height of each of the convex portions or the depth of each of the concave portions is d, the aspect ratio calculated as d/l is 0.5 or greater. 6. The method for manufacturing an information display body according to claim 5, wherein the information display portion is formed by vertically stacking a powdered hydraulic composition solidified by spraying an aqueous hardening agent onto the powdered hydraulic composition. The method for manufacturing an information display body according to claim 5 or 6, characterized in that the information display portion is formed by filling a formwork in which a three-dimensional shape of the information display portion has been preformed with cement and water, or a cement mixture prepared by kneading cement, water and aggregate, allowing it to harden, and then removing the formwork. 8. The method for manufacturing an information display according to claim 7, wherein the maximum particle size of the aggregate is equal to or smaller than the minimum width of the information display portion. 7. The method for manufacturing an information display body according to claim 5, wherein the information display portion is formed by cutting a hardened cement body. 10. The method for manufacturing an information display body according to claim 9, wherein the maximum particle size of the aggregate in the hardened cement body is 5 mm or less.