JP2013175583A - Curved surface substrate and method of manufacturing curved surface substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide curved surface substrate and a method of manufacturing the same, capable of providing both improvement in conductor pattern layer precision and improvement in productivity, with good power feeding to the conductor pattern layer.SOLUTION: A curved surface substrate includes a curved surface dielectric layer (1) in which a recess (11) is formed on each of front and rear surfaces, with the recess on the front surface and the recess on the rear surface connected together by a through hole (2d), conductor pattern layers (2a and 2b) that are formed by filling the recess on the front surface and the recess on the rear surface provided at the dielectric layer with conductive paste (2), and an interlayer connection part (2c) which is formed by filling the through hole provided in the dielectric layer with the conductive paste, for connection between the conductor pattern layers provided on the front and rear surfaces. The conductor pattern layer and the interlayer connection part are simultaneously formed by filling the recess on the front surface, the recess on the rear surface, and the through hole with the conductive paste in a single step.

Description

  The present invention relates to a curved substrate having a dielectric layer and a conductor pattern layer, and having a curved surface shape such as a spherical shape or a spheroid shape, and a method of manufacturing the curved substrate.

  A printed wiring board is known as a substrate provided with a conductor pattern layer (conductor layer) and a dielectric layer. The printed wiring board has a planar shape, and the conductor pattern layer (copper wiring) is generally formed by an exposure / development method using a photosensitive resist. On the other hand, for applications to radomes, antenna devices, etc., there is a demand for curved substrates such as spheres or spheroids, and various methods for realizing curved substrates are conventionally known. ing.

For example, the following is known as a conventional method for manufacturing a curved substrate (for example, see Patent Document 1).
(Method 1) A method in which a conductor pattern layer is formed on the entire surface in the same manner as in the case of a flat substrate and then exposed in a spot manner.
(Method 2) A method of curving a flat substrate on which a conductor pattern layer is formed.
(Method 3) A method in which a flat substrate on which a conductor pattern layer is formed is divided and laminated in a tile shape to form a curved surface as a whole.
(Method 4) A method in which a conductor pattern layer is formed on the entire surface, and then the conductor pattern layer is cut by machining.

JP-A-9-139619

However, the above prior art has the following problems.
In the exposure method of Method 1, when it is intended to form a highly accurate conductor pattern layer, it is necessary to control the exposure head three-dimensionally with a robot arm or the like. Therefore, in order to cope with a large curved surface, a large-scale exposure apparatus is required. Moreover, since it exposes many times like a spot, it is inferior to productivity.

  Since the curved surface processing method of Method 2 is a flat surface, if the curvature of the spherical surface is increased, wrinkles and displacement occur, and a highly accurate curved conductor pattern cannot be formed.

  Similarly, in the method 3 in which the curved substrates are pseudo-realized by bonding the flat substrates, the gaps and deviations are generated in the bonded portions because they are not strictly curved surfaces.

  The machining method of Method 4 can be manufactured by existing machining equipment and does not cause a deviation, but needs to be machined one by one and is inferior in productivity as the exposure method of Method 1.

  As described above, the conventional techniques according to the methods 1 to 4 have a problem that it is impossible to achieve both improvement of the conductor pattern accuracy and improvement of productivity. Furthermore, when this curved substrate is applied to an antenna device, there is a problem that it is difficult to feed power to the conductor pattern layer (feed patch layer).

  Accordingly, the present invention has been made to solve the above-described problems, and is a curved substrate that can improve the accuracy of the conductor pattern layer and improve the productivity, and can also feed the conductor pattern layer satisfactorily. It is another object of the present invention to provide a method for manufacturing a curved substrate.

  In order to solve the above problems, the curved substrate according to the present invention has a curved dielectric layer in which concave portions are formed on the front and back surfaces, and a concave portion on the front surface and a concave portion on the back surface are connected by a through hole. The conductive pattern layer formed by filling each of the concave portion on the front surface and the concave portion on the back surface provided in the dielectric layer with the conductive paste is filled in the through hole provided in the dielectric layer. The conductive pattern layer and the interlayer connection portion are each formed of a conductive paste in the concave portion on the front surface, the concave portion on the back surface, and the through hole. It is formed at the same time by filling in a single process.

  In addition, the method of manufacturing a curved substrate according to the present invention includes a step of forming a dielectric layer having a concave portion on the surface, and a dielectric layer in the method of manufacturing a curved substrate including a dielectric layer and a conductor pattern layer. For the two dielectric layers formed in the step of forming the dielectric layers, the surface of each dielectric layer where the recesses are not formed are bonded together via an adhesive layer, and in the stacking direction of the dielectric layers, A step of forming a through hole in a portion where the concave portions on the surface of each dielectric layer overlap each other, and a conductive pattern layer is formed in the concave portion by filling the concave portion and the through hole of each dielectric layer with a conductive paste. And a step of simultaneously forming an interlayer connection portion for connecting the conductor pattern layers in the hole.

  According to the present invention, the concave portions are formed on the front and back surfaces of the curved dielectric layer, and the holes penetrating between the concave portions are formed, and the conductive paste is filled in the concave portions and the through holes with the conductive paste. In addition, since the interlayer connection portion is formed, the time-consuming process can be limited to the manufacturing process of the dielectric layer of the mold by machining, and further, the conductor pattern layer, the interlayer connection portion, Since there is no interface between the conductor pattern layer and the interlayer connection portion, the curved pattern substrate can improve the accuracy of the conductor pattern and improve the productivity, and can feed the conductor pattern layer well. And the manufacturing method of a curved-surface-shaped board | substrate can be obtained.

It is sectional drawing which shows the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (1) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (2) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (3) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (4) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (5) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (6) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (7) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing process (8) of the curved-surface-shaped board | substrate by Embodiment 1 of this invention. It is sectional drawing which shows the curved-surface-shaped board | substrate by Embodiment 2 of this invention. It is sectional drawing which shows the curved-surface-shaped board | substrate by Embodiment 2 of this invention. It is sectional drawing which shows the manufacturing process of the curved-surface-shaped board | substrate by Embodiment 2 of this invention. It is sectional drawing which shows the radome integrated antenna by Embodiment 3 of this invention. It is sectional drawing which shows the manufacturing process (1) of the radome integrated antenna by Embodiment 3 of this invention. It is sectional drawing which shows the manufacturing process (2) of the radome integrated antenna by Embodiment 3 of this invention.

  Hereinafter, preferred embodiments of a curved substrate and a method of manufacturing a curved substrate of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a curved substrate 100 according to Embodiment 1 of the present invention. A curved substrate 100 shown in FIG. 1 has a dielectric layer 1 in which concave portions are formed on the front and back surfaces of a curved surface such as a sphere or a spheroid, and a conductive material filled in the concave portions on the front and rear surfaces. Conductor layers 2a and 2b made of conductive paste, and an interlayer connection portion 2c made of conductive paste for conducting between the conductor layers 2a and 2b. For the sake of simplicity, in the following description, the cross section of the curved surface is expressed in a pseudo manner by a planar cross section.

  2a to 2h are cross-sectional views respectively showing manufacturing processes (1) to (8) of the curved substrate according to the first embodiment of the present invention. First, as shown in FIG. 2A, a curved mold 3 is prepared. As the material of the mold 3, a metal such as SUS or aluminum, gypsum, or the like can be used. Preferably, aluminum is optimal from the viewpoint of weight.

  Next, as shown in FIG. 2 b, the groove 4 is formed in the curved mold 3. As will be described later, a portion where the groove 4 is not formed becomes a concave portion formed in the dielectric layer 1 later, and becomes a portion where the conductor pattern layer (conductor layer) 2 is formed. The depth of the groove 4 is preferably 0.05 mm or more and less than 0.3 mm.

  The reason for this is that if the depth of the groove 4 is less than 0.05 mm, the conductor pattern layer is also polished at the time of polishing. Conversely, if the depth of the groove 4 is 0.3 mm or more, the curved surface is curved. This is because, depending on the curvature of the shape, when the product is removed from the mold 3, the dielectric layer 1 of the groove 4 remains on the mold 3 and falls off. Furthermore, after forming the groove | channel 4, it is preferable to coat the shaping | molding die 3 with the fluororesin which has mold release property. This is to make it easier to remove the product from the mold 3.

  Next, as shown in FIG. 2c, the dielectric layer 1 is formed using a curved mold 3 in which the grooves 4 are formed. Here, the dielectric layer 1 is preferably made of fiber reinforced plastic (GFRP) made of fiber 5 and resin from the viewpoint of strength and rigidity. The fiber 5 used for the fiber reinforced plastic is not particularly limited as long as it is an insulating fiber. However, when applied to a radome or the like, quartz fibers having a small relative dielectric constant and dielectric loss tangent are preferable from the viewpoint of radio wave transmission.

  Further, the fiber 5 is preferably a plain weave cloth, and more preferably, when the fiber 5 is formed into a curved surface (that is, when it is formed into a curved surface with the molding die 3), the fiber 5 is thin and does not wrinkle even when stretched. A certain fiber cloth is preferable. The resin used for the fiber reinforced plastic is not particularly limited. However, a bis-E type cyanate ester resin, which has both radio wave permeability and heat resistance and is a low-viscosity liquid at room temperature, is preferable.

  In FIG. 2c, first, a quartz fiber 5 is placed on a curved mold 3 in which a groove 4 is formed, a peel ply 6 and a flow medium 7 are stacked thereon, and the whole is covered with a bagging film 8. Thereafter, the tube 10 is sealed with a sealant 9. Next, the inside of the bagging film 8 is depressurized through the tube 10 by a vacuum pump (not shown). Next, an uncured liquid resin having a low viscosity is supplied from a resin tank (not shown) through a tube 10 sealed with a sealant 9.

  At this time, the resin preferentially passes through the flow media 7 having a coarser mesh than the fibers 5, diffuses in the plane, is sent, soaks out of the plane, and impregnates the fibers 5. After the entire fiber 5 is impregnated with the resin, the resin supply port and the vacuum exhaust port are closed with a valve or the like, and the bagging film 8 is put in an oven while being depressurized and cured. When a bis-E type cyanate ester resin is used as the resin, the resin is held at 180 ° C. for 2 hours.

  Next, it removes from the shaping | molding die 3, and the fiber reinforced plastic 1a which has the recessed part 11 as shown in FIG. The peel ply 6, the flow media 7, and the bagging film 8 on the fiber reinforced plastic can be peeled off at the interface between the fiber reinforced plastic and the peel ply 6.

  By molding the dielectric layer 1a by the so-called VaRTM molding method (vacuum assisted resin transfer molding method: vacuum impregnation molding method), which is a method of manufacturing a fiber reinforced plastic by impregnating a resin by vacuum drawing. There is an advantage that the groove 4 is filled with resin.

  Also, by dividing the mold 3 and molding the fiber reinforced plastic, even if the curvature of the curved surface is large, it is not necessary to divide the fiber reinforced plastic to remove the mold, and the large fiber reinforced plastic is integrated. Can be molded.

  Next, as shown in FIG. 2e, two fiber reinforced plastics 1a having a recess 11 on one side are prepared, and the surfaces where no recess is formed are bonded together using an adhesive layer 12, and the recess 11 is formed on the front and back surfaces. Is formed by autoclave molding or press molding.

  The adhesive layer 12 is not particularly limited as long as it is insulating. However, when applied to a radome, etc., from the viewpoint of radio wave transmission, it is a semi-cured fiber reinforced plastic (prepreg) with the same relative dielectric constant and dielectric loss tangent, or so thick that it does not affect radio wave transmission. A thin adhesive film is preferred.

  Next, as shown in FIG. 2f, a through hole 2d is formed in a portion where the recesses 11 on the front and back surfaces formed in the dielectric layer 1b having recesses on the front and back surfaces overlap in the stacking direction. The through hole 2d can be formed by a drill, for example.

  Next, as shown in FIG. 2g, the conductive paste 2 is filled into the recesses 11 and the through holes 2d of the dielectric layer 1b having recesses on the front and back surfaces using a squeegee. Here, the conductive paste 2 is preferably a low-temperature dry type silver paste that develops conductivity without pressure. The conductive paste 2 is dried in an oven at 120 ° C. for 10 minutes after coating.

  Next, as shown in FIG. 2h, the conductive paste 2 is removed by polishing with sandpaper or a jig having the same curvature as that of the dielectric layer 1, and the conductive pattern layers 2a and 2b and the interlayer connection portion 2c are removed. Form. When cutting away the conductive paste other than the convex portions, it is necessary to prevent the fiber reinforced plastic 1 from being exposed.

  As described above, according to the first embodiment, the dielectric layer having the concave portion is formed using the curved mold having the concave portion, and the conductor is formed in the concave portion formed in the dielectric layer. Thus, a curved substrate is manufactured. Here, it is only necessary to perform the machining over time by using only the mold. Therefore, according to such a manufacturing method, it is possible to manufacture a plurality of curved substrate having a conductor pattern layer with high productivity.

  Furthermore, the accuracy of the conductor pattern layer depends on the accuracy of the recess formed in the mold, and the recess of the mold is formed by machining. For this reason, a highly accurate conductor pattern layer can be formed.

  Further, fiber reinforced plastic having a recess on one side is bonded using an adhesive layer on the surface where no recess is formed, a dielectric layer having a recess is formed on the front and back surfaces, and the recess formed in the dielectric layer is formed. A through hole is formed, and the conductive paste is filled and polished simultaneously in the recess and the through hole formed in the dielectric layer. Thereby, since there is no interface between the conductor pattern portion and the interlayer connection portion, it is possible to obtain a curved substrate having a highly reliable interlayer connection and a manufacturing method thereof.

  Furthermore, by forming a dielectric layer with recesses by the VaRTM method, resin can be filled in the protrusions without voids, and a relatively large curved substrate is integrally formed by dividing the mold. it can.

Embodiment 2. FIG.
In the second embodiment, a case will be described in which the shapes of the through hole 2d and the interlayer connection portion 2c are different from those of the first embodiment.

  3a and 3b are sectional views showing a curved substrate 200 according to the second embodiment of the present invention. The curved substrate 200 in the second embodiment basically has the same configuration as the curved substrate 100 in the first embodiment. However, in the curved substrate 200 according to the second embodiment, the shape of the interlayer connection portion 2c for conducting the conductor layers 2a and 2b is not a cylinder as in the first embodiment, but as shown in FIG. 3a. However, it is different in that it has a tapered shape. More preferably, as shown in FIG. 3b, it is different in that the shape has a symmetrical taper from both the front and back surfaces.

  FIG. 4 is a sectional view showing a manufacturing process of the curved substrate 200 according to the second embodiment of the present invention. The manufacturing process of the curved substrate 200 according to the second embodiment basically includes the same steps as the curved substrate 100 according to the first embodiment. However, the difference is that a taper is applied in the step of forming the through hole 2d in a portion where the front and back recesses 11 formed in the dielectric layer 1b having recesses on the front and back surfaces overlap. More preferably, the through hole 2d is formed so as to be tapered from the front and back surfaces. The tapered through hole 2d can be formed by, for example, a drill.

  As described above, according to the second embodiment, the shape of the interlayer connection portion for conducting the conductor layer is not a column but a tapered shape. As a result, the area of the interface between the conductor layer and the interlayer connection portion is large, and an interlayer connection with higher conduction reliability can be obtained.

Embodiment 3 FIG.
In the third embodiment, a radome integrated antenna to which the curved substrate of the present invention is applied will be described.

  FIG. 5 is a cross-sectional view showing a radome integrated antenna 300 according to Embodiment 3 of the present invention. The radome integrated antenna 300 according to the third embodiment includes a radome layer 301 provided with a conductor layer 2e (frequency selective surface (FSS)), and basically a curved substrate according to the first embodiment. The antenna layer 302 including the conductor layer 2f (ground layer) is provided between the conductor layer 2a (feeding patch) and the conductor layer 2b (distribution circuit), and the radome layer 301 and the antenna layer 302 are separated from each other. A foam material 13 is provided between them.

  The conductor layer 2a (power supply patch) has a function of transmitting radio waves, and the FSS has a function of transmitting and receiving only a specific frequency.

  6a and 6b are sectional views respectively showing manufacturing processes (1) and (2) of the radome integrated antenna 300 according to the third embodiment of the present invention shown in FIG. The manufacturing process of the radome integrated antenna 300 in the third embodiment basically includes the same steps as those of the curved substrate 100 in the first embodiment.

  However, as shown in FIG. 6a, two fiber reinforced plastics (GFRP) 1a each having a recess 11 on one side are prepared, and the surfaces where no recess is formed are bonded to each other on the front and back surfaces through an adhesive layer 12. A step of laminating a dielectric layer provided with a conductor layer 2f (ground layer: see FIG. 6b) in which the concave portion 11 is previously filled with the conductive paste 2 before the dielectric layer 1b having the concave portion is formed. Is different.

  Furthermore, as shown in FIG. 6b, a radome layer 301 provided with a conductor layer 2e formed by filling a recess provided on one side with a conductive paste, and an antenna layer 302 formed as shown in FIG. 6a, In addition, there is a difference in that a foam material 13 is disposed between the layers and a step of laminating with an adhesive layer 12 to form a sandwich structure.

  As described above, according to the third embodiment, the conductor layer can be provided between the conductor layers to be multilayered, and the radome layer and the antenna layer can be integrated. In general, the radome layer employs a sandwich structure in order to ensure rigidity to withstand wind pressure. However, the skin layer on the back surface can also serve as the antenna layer and can be reduced in weight.

  DESCRIPTION OF SYMBOLS 1 Dielectric layer (fiber reinforced plastic), 1a Dielectric layer which has a recessed part on one side, 1b Dielectric layer which has a recessed part on both surfaces, 2 Conductive paste, 2a Conductive layer (feeding patch), 2b Conductive layer (distribution circuit) 2c Interlayer connection part, 2d through hole, 2e Conductor layer (frequency selection surface), 2f Conductor layer (ground), 3 Curved mold, 4 Groove, 5 Fiber, 6 Peel ply, 7 Flow media, 8 Bagging film, 9 Sealant, 10 Tube, 11 Recess, 12 Adhesive layer, 13 Foam, 100, 200 Curved substrate, 300 Radome integrated antenna, 301 Radome layer, 302 Antenna layer.

Claims (6)

Recesses are formed on the front and back surfaces, respectively, and a dielectric layer having a curved shape in which a through hole is connected between the recesses on the front surface and the recesses on the back surface,
A conductor pattern layer formed by filling a conductive paste into each of the concave portion on the front surface and the concave portion on the back surface provided in the dielectric layer;
An interlayer connection portion formed by filling the through hole provided in the dielectric layer with a conductive paste, and connecting the conductor pattern layers provided on the front and back surfaces; and
The curved surface shape, wherein the conductive pattern layer and the interlayer connection portion are simultaneously formed by filling the concave portion on the front surface, the concave portion on the back surface, and the through hole with a conductive paste in one step. substrate. The curved substrate according to claim 1,
The through hole has a tapered shape. A first skin layer comprising the curved substrate according to claim 1 or 2;
A second skin layer including a curved dielectric layer having a recess formed on the back surface;
A curved substrate including a foam material sandwiched between the first skin layer and the second skin layer and having a sandwich structure with both skin layers. The curved substrate according to claim 3,
The first skin layer is an antenna layer constituting a feeding patch / distribution circuit,
The second skin layer is a radome layer that imparts frequency selectivity;
A curved substrate applied to a radome integrated antenna by having a sandwich structure in which a foam material is sandwiched between both skin layers. In the method of manufacturing a curved substrate composed of a dielectric layer and a conductor pattern layer,
Forming a dielectric layer having a recess on the surface;
For the two dielectric layers formed by the step of forming the dielectric layer, bonding the surfaces of each dielectric layer where the recesses are not formed, with an adhesive layer interposed therebetween,
Forming a through hole in a portion where the recesses on the surface of each dielectric layer overlap in the stacking direction of each dielectric layer; and
By filling the recesses and the through holes of each dielectric layer with a conductive paste, a conductor pattern layer is formed in the recesses, and an interlayer connection for connecting the conductor pattern layers is simultaneously formed in the through holes. A process for producing a curved substrate, comprising: a step. In the manufacturing method of the curved-surface-shaped board | substrate of Claim 5,
The process for forming the dielectric layer employs a VaRTM method (vacuum impregnation molding method) to form a dielectric layer made of fiber-reinforced plastic.

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