JP2004332111A - Black particle, plating device for preparing black particle and light-absorbing body using black particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-absorbing body which has no limitation on the angle of incidence of light or the size, shape or material of a substrate. <P>SOLUTION: On the surface of a black particle 20, fine irregularities 22a for absorbing light are radially formed around a core body 21 by etching a coating film 22 of a nickel-phosphorus alloy plated on the surface of the granular core body 21. The black particle 20 absorbs light from all directions heading toward the center of the core body 21 at a low reflectivity. The light-absorbing body having no limitation on the angle of incidence of light or the size, shape or material of the substrate can be manufactured by attaching the black particle 20 to a prescribed surface of the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light absorber for absorbing light, and relates to a technique for eliminating restrictions on the size, shape, and material of a substrate, and restrictions on a light incident angle.

  For example, in an optical power meter for precisely measuring the power of light, a light to be measured is received by a light receiving unit, converted into heat, and a temperature change due to the heat is measured, and a light absorber is used as the light receiving unit. Used.

  The light absorber used for such a purpose is required to have high light absorptivity, that is, low reflectivity.

  At present, as a light absorber having the highest light absorption rate, a NiP (nickel / phosphorus) alloy is plated on the surface of the substrate, and the NiP alloy film is etched to form fine irregularities for absorbing light. What is referred to as blackening is often used (Patent Document 1).

  The light reflectance of the thus formed light absorber is 0.1 to 0.4% in a wide wavelength band.

Japanese Patent No. 2661983

  However, as described above, in the method of manufacturing a desired light absorber by performing plating and etching on the base material of the light absorber itself, the size, shape, and material of the light absorber that can be manufactured are limited. .

  That is, basically, a light absorber larger than a plating tank or an etching tank cannot be produced, and a light absorbing layer is formed on the inner wall surface of a cylindrical substrate such as a microscope or a telescope, or the width of the light absorbing layer is larger. When there is a narrow groove or the like, it becomes difficult to flow the plating solution or the etching solution in the cylinder or the groove, and the production quality greatly varies.

  In addition, the base material of the light absorber is limited to a material that is hard and does not deform so as to withstand a plating process and an etching process. For example, a flexible sheet material such as paper or cloth is used as a base material. Could not be made.

  Another problem is that the incident angle at which the light absorptance is high is limited. That is, as shown in FIG. 13, the coating 2 plated on the surface of the substrate 1 is eroded in the thickness direction by the etching process, so that the fine irregularities 2 a are substantially in the direction orthogonal to the surface of the substrate 1. Since the light A incident in the direction perpendicular to the surface of the substrate 1 is deeply absorbed into the valley portion and absorbed, the reflectance is very low. The light A 'incident at a shallow angle with respect to the light is reflected in the incident direction on the slope on the tip end side of each peak and cannot enter the valley, so that the reflectance increases. That is, the range of the incident angle of the light to be absorbed is limited.

  The present invention solves these problems, and restricts the incident angle of light to be absorbed, the size and shape of the substrate, black particles capable of realizing light absorption without restriction by the material, a plating apparatus for producing black particles, and It is intended to provide a light absorber.

To achieve the above object, the black particles according to claim 1 of the present invention include:
Fine irregularities (22a) for absorbing light are formed radially around the core on the surface of the granular core (21).

The black particles according to claim 2 of the present invention are the black particles according to claim 1,
It is characterized in that one particle contains a plurality of the nuclei.

The black particles according to claim 3 of the present invention are the black particles according to claim 1 or claim 2,
The fine irregularities are formed by etching a nickel-phosphorus alloy plated on the surface of the core.

Further, the plating apparatus for producing black particles according to claim 4 of the present invention,
A plating apparatus for producing black particles for plating metal on the surface of a granular core body that is a source of black particles,
A container (101) formed in a bottomed cylindrical shape, receiving the plurality of cores and the plating solution from an opening on one end side, and storing the plating solution in the bottom on the other end side;
A support member (102) for supporting the container in a state where a line connecting the opening and the bottom is inclined with respect to a vertical line;
A heating and warming device (103) for heating and maintaining the plating solution contained in the bottom of the container at a predetermined temperature;
A rotation driving device that rotates the container supported by the support member about a line connecting the opening and the bottom as a central axis, stirs the plating solution in the bottom, and rolls the core in the plating solution. (104).

Further, the light absorber according to claim 5 of the present invention is:
The black particles according to claim 1, 2, or 3 are adhered to a predetermined surface of the substrate.

Further, the light absorber according to claim 6 of the present invention is the light absorber according to claim 5,
The black particles are adhered to a curved surface or an uneven surface of the substrate.

Further, the light absorber according to claim 7 of the present invention is the light absorber according to claim 5,
The black particles are adhered to the surface of a flexible sheet-shaped substrate.

  As described above, in the black particles of the present invention, fine irregularities for absorbing light are formed radially around the core on the surface of the granular core. By adhering to a surface, a light absorber that can absorb light from all directions can be formed with an arbitrary size, shape, and material.

  Further, when the core is small, black particles containing a plurality of cores in one particle may be obtained, and even with such black particles, due to fine irregularities formed on the surface, Absorb light efficiently.

  Further, in the case where fine irregularities are formed by etching a nickel-phosphorus alloy plated on the surface of a core, an extremely low reflectance can be obtained with respect to incident light from all directions.

  In addition, as a device for plating the core body of the black particles, a bottomed cylindrical container containing the plating solution and the core body is connected to the vertical line with the line connecting the opening and the bottom thereof. A structure in which the plating solution accommodated in the bottom is heated and maintained at a predetermined temperature, rotated about a line connecting the opening and the bottom as a central axis, and the plating solution in the bottom is agitated. By using it, the configuration can be facilitated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a process for producing the black particles of the embodiment. The manufacturing process of the black particles will be described with reference to FIG.

First, as shown in FIG. 1A, a number of granular cores 21 are prepared.
The nucleus 21 is formed of a metal, ceramics, glass, plastic, or the like, and is formed in a spherical shape having a diameter of, for example, about 5 μm to 5 mm.

  The size of the nucleus 21 is determined according to the surface size and unevenness of the light absorber constituted by adhering the black particles, and the shape is preferably a point-symmetrical true sphere, but is preferably an elliptic sphere or a polyhedral sphere. And so on.

  Next, a pretreatment for plating is performed in accordance with the material of the core 21, and the pretreated core 21 is immersed in the plating solution 2 in the plating tank 1 as shown in FIG. Thus, a NiP alloy film 22 is formed on the entire surface of the core 21.

  Here, as the pretreatment for the plating treatment, when the core 21 is a metal, the core 21 is degreased with an organic solvent and an alkaline degreasing solution and then pickled. When the core 21 is made of a metal other than nickel, a nickel strike plating process may be performed thereafter.

  When the core 21 is a non-conductor such as glass, ceramics or plastic, the surface of the core is activated with a tin chloride solution and a palladium chloride solution.

  The plating solution 2 is composed of a nickel salt, a reducing agent, oxycarboxylic acid, and dicarboxylic acid, and has a total amount of 0.6 to 1.2 mol / liter.

More specifically,
Nickel sulfate 0.11 to 0.20 M (mol: the same applies hereinafter) as a nickel salt;
Sodium phosphinate 0.24 to 0.36 M as a reducing agent,
0.4 to 0.8 M of DL malic acid as an oxycarboxylic acid,
Malonic acid as a dicarboxylic acid 0.20 to 0.40M
Is immersed at a liquid temperature of 80 to 95 ° C. for an appropriate time of 10 minutes to 30 hours to form a NiP alloy film 22 on the entire surface of the core 21, for example, with a thickness of 10 to 80 μm. Formed. The plating time is determined according to the surface area of the core 21 and the thickness of the NiP alloy film 22.

  Although not shown, the core 21 is immersed in the plating tank 1 in a state in which the plating solution 2 is housed in a basket-like container through which the plating solution 2 can flow, and the container 21 is appropriately vibrated to give the core 21 a Is floated in the container to form a NiP alloy film 22 with a substantially constant thickness on the surface of each core 21.

  By this plating process, a NiP alloy film 22 having a predetermined thickness is formed on the surface of the core 21 as shown in FIG. 1 (c), which is then washed with water and dried. The nucleus 21 is immersed in the etching solution 4 in the etching bath 3 as described above to etch and blacken the NiP alloy film 22 of each nucleus 21.

  Here, the etching solution 4 is a nitrate, for example, sodium nitrate having a concentration of 200 to 450 g / l, and a solution to which sulfuric acid having a concentration of 300 to 700 g / l, preferably 400 to 600 g / l is added. Etching is performed at a liquid temperature of 30 to 80 ° C. and an immersion time of 5 seconds to 5 minutes.

  By this etching treatment, the NiP alloy film 22 is eroded from the surface layer side in the thickness direction (the core center side).

  In this etching treatment, the container is vibrated in the same manner as in the plating treatment so that the individual coatings 22 of the nuclei 21 uniformly come into contact with the etching solution over the entire circumference.

  After this etching, by washing with water and drying, as shown in FIG. 1 (e), black particles 20 having a particle diameter of 10 μm to 5 mm in which fine irregularities 22a are radially formed on the outer surface around the core 21 are formed. Complete.

  FIG. 2 is an enlarged photograph of fine irregularities 22a actually formed by etching, and it can be seen that countless mountain-shaped irregularities are formed on the entire surface.

  The reflectance of the surface of each of the black particles 20 thus formed is 0.05 to 0.4% in a wavelength range of 320 nm to 2200 nm, and a low reflectance is obtained even in an infrared region.

  Further, as shown in FIG. 3, fine irregularities 22a for absorbing light are radially formed around the core 21 by etching, so that if the light is directed toward the center of the core 21, Light A from any direction can enter the valleys of the irregularities 22a, and can be uniformly absorbed at a low reflectance.

  By using the black particles 20 thus obtained, a light absorber having an arbitrary size, shape, and material can be formed.

  Hereinafter, methods for forming light absorbers of various shapes and materials using the above-described black particles 20 will be described.

  First, in the case of forming a large flat light absorber, as shown in FIG. 4A, for example, an epoxy-based adhesive 32 is applied to the entire surface 31a of the flat base material 31. As shown in (b), the black particles 20 are sprinkled (or sprayed) so as to cover the entire surface of the adhesive 32 and adhere without gaps, and the black particles 20 on the surface layer that are not in contact with the adhesive 32 are removed.

As a method of removing the unnecessary black particles 20, there are a method of dropping the base material 31 upside down, a method of blowing air, and a method of sucking with air.
Thereby, as shown in FIG. 4C, a large flat light absorber 30 having one surface uniformly covered with the black particles 20 is obtained.

  In the light absorber 30 configured as described above, as described above, the black particles 20 having a uniform and low reflectance with respect to the incident angle of light cover the surface 31a of the base material 31, so that the surface 31a Light incident at a deep angle perpendicular to the plane or light incident at a shallow angle can be absorbed with low reflectance.

  Therefore, even when the incident angles of the light to be absorbed are different, the light can be absorbed by the common light absorber 30. Further, when the light path of the light to be absorbed is limited to one, the position and the direction of the light absorber 30 can be arbitrarily set as long as the light path and the surface 31a cross each other. The degree of freedom at the time of design becomes very large.

  FIG. 5 shows a case where a light absorber having a cylindrical shape and having a light absorption layer therein is formed, such as a microscope or a telescope. 5A and 5B show schematic cross sections of the cylindrical base material 41. As shown in FIG. 5A, the entire inner peripheral surface 41a of the base material 41 is epoxy-based. After the adhesive 32 is applied, the black particles 20 are adhered to the entire surface of the adhesive 32 without gaps as shown in FIG.

  As a result, a cylindrical light absorber 40 whose entire inner peripheral surface is covered with the black particles 20 is obtained. It should be noted that a cylindrical light absorber other than a cylinder can be similarly manufactured.

  Also, even when the groove 52 is formed on the surface 51a side of the base material 51 as shown in FIG. 6A, the epoxy-based adhesive 32 is applied to the entire surface 51a in the same manner as described above. As shown in FIG. 6B, the black particles 20 are adhered to the entire surface of the adhesive 32 without gaps.

  Thus, the light absorber 50 in which the entire surface 51a including the inner wall of the groove 52 is uniformly covered with the black particles 20 is obtained. Note that the same configuration can be applied to a case where a rib is provided instead of the groove 52 or a case where both the groove and the rib are provided.

  When a flexible sheet-like light absorber is formed, one surface 61a of a flexible sheet-like base material 61 such as paper, cloth, or synthetic resin as shown in FIG. The adhesive 42 is applied to the whole (or part), and the black particles 20 are adhered to the entire surface of the adhesive 42 without gaps as shown in FIG. 7B.

  Thereby, the sheet-shaped light absorber 60 having flexibility is obtained. The adhesive used in this case is a soft adhesive that does not lose the flexibility of the base material 61.

  The light absorber 60 is used not only by attaching it to a large flat wall surface, for example, but also by bending (or bending) as shown in FIG. 7C even when the attaching surface is a curved surface. be able to.

  Further, it can be cut into an appropriate size and attached to the surface of an arbitrary object for use, or a roll-shaped curtain can be used.

  Further, the black particles 20 may be adhered to a part of the surface of the flexible substrate of the electric circuit in the same manner as described above to provide the light absorber on the flexible substrate.

  Note that a double-sided adhesive tape may be used instead of the adhesives 32 and 42 for adhering the black particles 20 to a predetermined surface of the base material. Further, in the case of a substrate made of a synthetic resin such as plastic, the surface layer of the predetermined surface is softened by heating or softened with a solvent, and the softened portion is used as an adhesive layer to adhere the black particles 20. You may.

  Further, in the above description, the particle diameter of the black particles 20 adhered to the base material of the light absorber is one type. However, as shown in the light absorber 70 of FIG. The mixture of the particles 20b is bonded to the predetermined surface 71a of the base material 71 via the adhesive 32 (42), and the gap between the large-diameter black particles 20a is filled with the small-diameter black particles 20b. Light absorption can be more perfect. It is also possible to use a mixture of three or more types of black particles having different diameters.

  As described above, the light absorber using the black particles 20 can be configured for a large substrate, a substrate having a curved or uneven surface, or a flexible substrate. The present invention can be widely applied to structural members of optical instruments such as microscopes, telescopes, cameras, etc., solar heat absorbers of solar water heaters, wall materials of optical laboratories, and the like.

  In the above description, when plating the core 21, the core 21 is accommodated in a basket-like container through which the plating solution 2 can flow, immersed in the plating tank 1, and the container is appropriately vibrated. Although the method has been shown, the basket 21 may be moved in the plating tank 1 while the plating solution 2 in the plating tank 1 is stirred by a magnetic stirrer or the like, so that the plating process on the core 21 may be performed. A method in which the body 21 is placed directly in the plating tank 1 and stirred by a magnetic stirrer can also be adopted.

  The present inventors have found, as still another plating method, a structure that is simple in structure and relatively uniform.

FIG. 9 shows a configuration example of a plating apparatus 100 for producing black particles.
The plating apparatus 100 has a bottomed cylindrical container 101 that receives the core 21 and the plating solution 2 from the opening 101a and stores it in the bottom 101b, and the line C connecting the opening 101a and the bottom 101b is in the vertical direction. The support member 102 rotatably supports in a state inclined with respect to, the heating and warming device 103 for heating and holding the plating solution 2 stored in the container 101 at a predetermined temperature, and the container 101 are rotated about the line C as a central axis ( And a rotary driving device 104 for stirring the plating solution 2 in the bottom portion 101b and rolling the core 21 in the plating solution 2.

  Here, the container 101 may have a bottomed cylindrical shape having plating resistance and heat resistance. For example, the container 101 is made of heat-resistant glass and has a flask shape (beaker shape or test tube shape or the like) as shown in the figure. The supporting member 102 has a structure capable of holding the mouth portion rotatably while restricting the lowering of the container 101.

  The heating / warming device 103 has a structure in which a liquid (water, oil, or the like) 103b in a heat holding tank 103a is heated by a heater 103c to maintain the temperature at a predetermined temperature. The temperature of the plating solution 2 of 101 is maintained at 80 to 95 ° C. suitable for plating. Note that the heater 103c may be outside the heat retaining tank 103a.

  Further, the rotation driving device 104 is formed integrally with the support member 102, and transmits, for example, the rotational force of a motor (not shown) to the mouth of the container 101, and rotates the container 101 at a constant speed (eg, (Several rotations per minute) to stir the plating solution 2 in the bottom 101b and to roll the nuclei 21 in the plating solution 2.

  In the plating apparatus 100 having this configuration, the container 101 itself is rotated in a tilted state to stir the plating solution 2 and to roll the nucleus 21 in the plating solution 2, so that the movable member for stirring is placed in the plating tank. There is no need to provide the NiP alloy film 22 on the surface of the nucleus 21 with a simple configuration, and the film 22 of the NiP alloy can be formed to a substantially constant thickness.

The following method is performed as a specific example of the etching process.
That is, after the plating process is completed as described above, the contents of the container 101 are put into a basket-like container 111 as shown in FIG. Only the core 21 is left, and as shown in FIG. 10B, the core 21 is set in the tank 121 of the air-etching etching apparatus 120.

  Then, as shown in FIG. 10C, the etching liquid 4 is poured into the basket-like container 111 while bleeding air from the tank by the pump 122. The etching solution 4 flows out into the evacuated tank while etching the plating portion of the core 21 of the basket-like container 111. By continuing the pouring of the etching solution 4 for a certain period of time, the etching of the plating layer of the core 21 is completed.

  After the completion of the etching, the contents (black particles 20) in the basket-like container 111 are washed with water and dried to obtain the above-described black particles 20.

  In the above description, one nucleus 21 is included in one black particle 20. However, when the nucleus 21 is small (for example, several tens μm), the plating process by the plating apparatus 100 is performed. In the process, as shown in FIG. 11A, it has been confirmed that a plurality of nuclei 21 covered with a common coating 22 can be obtained.

  By performing the same etching process as described above on the one including a plurality of cores 21 as described above, fine irregularities 22a are radially formed on each core 21 as shown in FIG. The formed black particles 20 can be obtained.

  FIG. 12 is an enlarged photograph showing an example of the fine unevenness, and it can be seen that countless fine unevenness is radially formed on the entire surface as in FIG.

  Therefore, also in the case of the black particles including such a plurality of cores 21, similarly to the above, a low reflectance can be obtained over a wide angle range with respect to light, and this can be obtained by using each of the bases 31, 41, 51 as described above. , 61, the same as the light absorbers 30, 40, 50, 60 can be obtained.

Diagram for explaining the production process of the black particles of the present invention Enlarged photograph of the surface of the black particles Schematic diagram for explaining the light absorbing action of the surface of the black particles The figure which shows the manufacturing method of a flat light absorber. The figure which shows the manufacturing method of a cylindrical light absorber. The figure which shows the manufacturing method of the light absorber which has unevenness in the base material surface The figure which shows the manufacturing method of the light absorber which has a sheet-shaped base material which has flexibility. Structural diagram of light absorber using black particles with different diameters Configuration diagram of plating equipment Process diagram of etching process Schematic diagram of black particles containing a plurality of cores 21 Enlarged photograph of the surface of the black particles Diagram for explaining the relationship between the angle of incident light and the reflectance of a conventional light absorber

Explanation of reference numerals

  20, 20a, 20b: black particles, 21: core, 22: coating, 22a: unevenness, 30, 40, 50, 60, 70 ... light absorber, 31, 41, 51, 61, 71 ... Base material, 32, 42 ... Adhesive, 100 ... Plating device, 101 ... Container, 102 ... Support member, 103 ... Heating and warming device, 104 ... Rotary driving device, 111 ... Cage-like container , 120: Etching device, 121: Tank, 122: Pump

Claims (7)

  Black particles in which fine irregularities (22a) for absorbing light are radially formed around the core on the surface of the granular core (21).   The black particle according to claim 1, wherein a plurality of the nuclei are contained in one particle.   The black particles according to claim 1, wherein the fine unevenness is formed by etching a nickel-phosphorus alloy plated on a surface of the core. 4. A plating apparatus for producing black particles for plating metal on the surface of a granular core body that is a source of black particles,
A container (101) formed in a bottomed cylindrical shape, receiving the plurality of cores and the plating solution from an opening on one end side, and storing the plating solution in the bottom on the other end side;
A support member (102) for supporting the container in a state where a line connecting the opening and the bottom is inclined with respect to a vertical line;
A heating and warming device (103) for heating and maintaining the plating solution contained in the bottom of the container at a predetermined temperature;
A rotation driving device that rotates the container supported by the support member about a line connecting the opening and the bottom as a central axis, stirs the plating solution in the bottom, and rolls the core in the plating solution. (104). A plating apparatus for producing black particles, comprising:   4. A light absorber having the black particles according to claim 1, 2 or 3 adhered to a predetermined surface of a substrate.   The light absorber according to claim 5, wherein the black particles are adhered to a curved surface or an uneven surface of the substrate.   The light absorber according to claim 5, wherein the black particles are adhered to a surface of a flexible sheet-like substrate.

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