JP2002373324A - Non-contact communication information carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact communication-type information carrier which can be excellently handled and produced and is inexpensive. SOLUTION: A core piece 11 is configured by mounting an IC chip on which an antenna coil 3 is formed integrally all over the chip surface within the recessed part 6 of a core piece main body 5, and the core piece 11 is mounted at a prescribed position of the non-contact communication-type information carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact communication type information carrier provided with a semiconductor device in which a non-contact communication antenna is integrally formed on an IC chip.

[0002]

2. Description of the Related Art Conventionally, an IC chip integrally formed with an antenna coil is mounted on a component or product for inventory management of the component or product, or used for applications such as entry / exit management and commuter passes. For this purpose, there has been proposed a personal identification card in which an IC chip integrally formed with an antenna coil is embedded in a card body.

[0003]

However, the IC chip integrally formed with the antenna coil is hard, and when the IC chips come into contact with each other, the coil forming surface is easily damaged.
C-tips cannot be bagged or supplied by the parts feeder, and must rely on expensive material handling.

Further, an IC in which an antenna coil is integrally formed.
The chip is extremely thin (having a thickness of about 0.2 mm to 0.6 mm) and is highly brittle, so that cracks or chips are likely to occur due to stress on the coil forming surface side (or the back side).
Secondary processing is difficult.

[0005] Furthermore, insert molding of a chip using resin is possible, but since there is a large difference in physical characteristics between an IC chip integrally formed with an antenna coil and a molding resin, the moldability is poor and a large number of chips can be formed. It has drawbacks such as difficulty and high cost.

In addition, when insert molding is used, there is a disadvantage that thermal expansion due to buried resin and stress strain generated during use directly affect the IC chip, and in the worst case, the IC chip is destroyed.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide an inexpensive non-contact communication type information carrier which has good handleability and productivity.

[0008]

In order to achieve the above object, a first means of the present invention is to form a core piece by mounting an IC chip integrally formed with an antenna coil on one surface in a recess of a core piece body, The core piece is mounted on a predetermined position of a non-contact communication type information carrier.

In a second aspect of the present invention, in the first aspect, a circular concave portion is formed in the core piece main body, the square IC chip is inserted into the concave portion, and the periphery of the opening of the concave portion is turned inward. The IC chip is held in the recess by the caulking portion.

According to a third aspect of the present invention, in the first aspect, the IC chip is arranged in the concave portion such that the antenna coil faces the bottom of the core piece main body, and the bottom of the core piece main body is formed on the surface of the information carrier. The core piece is attached to the information carrier so as to be disposed on the side, and the bottom surface of the core piece main body does not protrude from the surface of the information carrier.

According to a fourth aspect of the present invention, in the first aspect, the antenna coil is formed on the IC chip such that the IC chip is square and the center of winding of the antenna coil substantially coincides with the center of the IC chip. A circular recess having a diameter substantially equal to the length of the diagonal line of the IC chip was formed at the center position of the core piece main body, and the IC chip was mounted in the recess to form a core piece, and the core piece was mounted on the information carrier. It is characterized by the following.

According to a fifth aspect of the present invention, in the fourth aspect, the non-contact communication information carrier has a disk shape.
A circular fitting recess is formed at the center of the disc-shaped information carrier, and the core piece is mounted in the fitting recess.

According to a sixth aspect of the present invention, in the first or the second means, the base material of the core piece and the non-contact communication type information carrier is made of plastic, and the material of the core piece is the non-contact communication type information carrier. It is characterized by being a material harder than the material of the carrier.

According to a seventh aspect of the present invention, in the first aspect, the non-contact communication information carrier is a case for storing various test objects such as a DNA chip, a test tube, and a test piece. It is a feature.

According to an eighth aspect of the present invention, in the first aspect, the core piece main body is made of a transparent or translucent material.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a core piece for a non-contact communication type information carrier according to the first embodiment, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, FIG. Enlarged plan view of the IC chip, FIG.
And FIG. 6 are a plan view and a cross-sectional view for explaining a step of mounting the IC chip on the core piece main body.

As shown in FIGS. 3 and 4, a square I
A rectangular spiral antenna coil 3 is integrally formed on the surface of the C chip 1 on the circuit forming side with an insulating layer 2 made of polyimide resin or the like interposed therebetween. The antenna coil 3 can be formed by an electroforming plating method or a photoresist method, and both ends are connected to the input / output terminals 4 and 4 of the IC chip 1 through through holes formed in the insulating layer 2.
The length of one side of the IC chip 1 integrally formed with the antenna coil 3 is about 2 mm to 4 mm, and the thickness is 0.2 mm to
It is about 0.6 mm.

This IC chip 1 is carried on a core piece body 5 as shown in FIGS. Core piece body 5
Is molded of engineering plastic such as thermoplastic plastic, has a circular concave portion 6 in the center as shown in FIGS. 5 and 6, and a projection-shaped caulking allowance 7 is integrally formed around the opening of the concave portion 6. I have. As shown in FIG. 5, the inner diameter D of the concave portion 6 is designed to be substantially equal to the diagonal length L of the IC chip 1, and by inserting the IC chip 1 into the concave portion 6,
The center of the IC chip 1 and the center of the core piece main body 5 coincide, that is, the IC chip 1
Are positioned.

As shown in FIG. 6, the IC chip 1 is inserted into the concave portion 6 with the antenna coil 3 side down, and the ultrasonic welding horn 8 is pressed from above the core piece main body 5 to soften the crimping allowance 7 inward. Then, as shown in FIGS. 1 and 2, a caulking portion 9 for locking the four corners 1a to 1d of the IC chip 1 is formed, and the IC chip 1 is inserted and carried in the concave portion 6 ( Swaging method).

In this example, the IC chip 1 is inserted into the concave portion 6 with the antenna coil 3 side facing down, and the antenna coil 3 is protected by the bottom 12 of the concave portion 6. Even when the IC chip 1 is inserted into the concave portion 6, the surface of the antenna coil 3 is lower than the upper surface of the core piece main body 5 by the thickness of the caulked portion 9, so that the antenna coil 3 is supplied by bagging or a part feeder. Sometimes, the antenna coil 3 is not damaged and has a protective effect. If the core piece body 5 is formed of a transparent or translucent plastic, it is convenient to check whether or not the IC chip 1 is mounted.

FIG. 7 is a view showing another example of carrying the IC chip 1.
It is inserted and carried inside. Also in this case, the IC chip 1 is inserted into the recess 6 with the antenna coil 3 side down.

By supporting the IC chip 1 in the recess 6 of the core piece body 5 in this manner, the antenna coil 3
Can be protected and the size can be easily handled, so that it can be mass-produced as the core piece 11 and attached to a member to which the IC chip 1 is to be originally mounted. In particular, it is possible to protect the IC chip corners 1a to 1d in which chip chipping is likely to occur due to stress or the like during handling of the IC chip 1 or after fitting with the target product by the core piece.

8 to 10 are views showing an example in which the core piece 11 is mounted on the token 13 used for electronic money transactions and the like. FIG. 8 is a plan view showing a state before the core piece 11 is mounted, and FIG. FIG. 9B is a plan view of FIG.
It is an expanded sectional view on the B line. As shown in FIG. 8, a fitting recess 14 having the same shape as the core piece 11 is formed in the center of a token 13 having a circular shape formed of a plastic molded body, and the core piece 11 is fitted and fixed therein.

At this time, as shown in FIG. 10, the bottom portion 12 of the core piece main body 5 is mounted on the front side, that is, the antenna coil 3 is mounted so as to be as close as possible to the front side, and the surface of the bottom portion 12 protrudes from the surface of the token 13. Not fixed. By attaching the core piece 11 to the token 13 in this manner, various information necessary for electronic money transactions, such as a password and a transaction history, is stored.
The C chip 1 can be used.

The core piece 11 and the token 13 may be connected to each other by using an adhesive, or the core piece body 5 and the token 13 may be provided with projections and depressions serving as fitting portions (connection portions).

The material of the core piece 11 is engineering plastic such as polycarbonate, or PPS (polysulfan) or PEI for applications requiring further heat resistance.
Super engineering plastics such as (polyether imilo) are preferable, and the material of the token 13 is A
BS and the like are preferred.

When the material of the core piece 11 and the material of the information carrier such as the token 13 into which the core piece 11 is fitted are considered in terms of fitting and stress relaxation, the material hardness of the information carrier such as the token 13 is compared with the material hardness of the information carrier such as the token 13. Choose a hard material.

When a material of the same kind as the core piece 11 and the information carrier or a soft material of the core piece is selected, stress is generated when the core piece 11 is fitted into the concave portion of the information carrier such as the token 13 or at the time of use after the fitting. In this case, stress is applied to the main body of the core piece 11 and chip cracks occur at the corners 1a to 1d of the IC chip. However, as in the present embodiment, the material of the core piece 11 which is harder than the material hardness of the information carrier is used. The selection alleviates the stress applied to the IC chip, thereby making it possible to avoid chip breakage and circuit breakage of the IC chip.

The above-mentioned hardness is indentation hardness such as Rockwell hardness, durometer hardness, and Bacall hardness.
In particular, a durometer hardness, which is a hardness determined from the depth of a depression under a test load specified in JIS K7215, is preferable.

FIGS. 11 to 16 are views for explaining a second embodiment of the present invention. FIG. 11 is a plan view of an IC chip, FIG. 12 is an enlarged view of FIG. 11C, and FIG. FIG. 14 is a plan view of the core piece, FIG. 15 is a plan view of the core piece, and FIG. 16 is a front view of the core piece.

Depending on the capacity and version of the IC chip 1,
The outer shape of the IC chip 1 may be reduced. On the other hand, the outer shape of the core piece main body 5 may not be reduced due to the relationship with the information carrier to which it is attached. The present embodiment is a preferred example in such a case.

The IC chip 1 used in this embodiment has a square shape with a side length of 2.3 mm, and a spiral is formed on the surface on the circuit forming surface side via an insulating layer (not shown) made of polyimide resin or the like. The antenna coil 3 is formed integrally. The antenna coil 3 is formed in a rectangular shape along the outer shape of the IC chip 1. In this embodiment, the coil width is about 14 μm, the gap between the coils is about 4 μm, and the number of turns is about 47 turns. Both ends of the antenna coil 3
It is connected to input / output terminals 4 and 4 through through holes formed in the insulating layer. As shown in FIG. 11, the antenna coil 3 is formed on the IC chip 1 so that the center O1 of the IC chip 1 and the winding center O2 of the rectangular spiral antenna coil 3 coincide.

The core piece body 5 has a disk shape and is formed of a thermoplastic resin such as a polycarbonate resin or an epoxy resin as described above, and has a circular concave portion 6 at the center as shown in FIGS. A projection-shaped caulking margin 7 is integrally formed around the opening of the recess 6. Caulking fee 7
One or a plurality of V-shaped or U-shaped notches 21 are formed in the circumferential direction.

The diameter D of the recess 6 shown in FIG. 13 is designed to be substantially equal to the diagonal length L of the IC chip 1 shown in FIG.
By inserting the IC chip 1 into the recess 6, the winding center O2 of the antenna coil 3 and the center O of the core piece main body 5 are set.
3 so that the antenna coil 3 (IC chip 1) is positioned at the center in the core piece body 5.

The IC chip 1 is inserted into the recess 6 as shown in FIG. 16 with the antenna coil 3 side down, and an ultrasonic welding horn is pressed from above the core piece body 5 to heat and soften the crimping allowance 7 inward. As shown in FIGS. 15 and 16, a caulking portion 9 for locking the four corners 1 a to 1 d of the IC chip 1 is formed, and the IC chip 1 is fixed in the recess 6.

By providing the notch portion 21 as described above, when the crimping allowance 7 is heated and softened inward and crimped, the crimping portion 9 extends long and inward as shown in FIG. Is formed, and even the IC chip 1 having a small outer shape can be reliably fixed in the core piece body 5. Also I
By installing the C chip 1 in the recess 6 with the antenna coil 3 side facing down, the antenna coil 3 can be protected by the bottom 12 of the recess 6.

As shown in FIGS. 14 and 16, one or more annular ribs 22 are formed on the outer periphery of the core piece main body 5. When the core piece main body 5 (core chip 11) is press-fitted into the fitting recess 14 of the token 13 as shown in FIG. 8, the core piece main body 5 is strongly fitted into the fitting recess 14 due to the presence of the annular rib 22. 5
And the connection strength of the token 13 can be increased. In the present embodiment, the annular ribs 22 that are continuous along the circumferential direction are provided, but the same effect can be obtained by providing the ribs intermittently along the circumferential direction.

The core chip 11 formed by fitting the IC chip 1 to the core piece body 5 as described above is pressed into the fitting recess 14 of the disk-shaped token 13 as shown in FIGS. A non-contact communication type information carrier according to the embodiment. Since the fitting recess 14 is formed at the center position of the token 13, the orientation of the IC chip 1 is arbitrary, but the center O4 of the token 13 coincides with the center O2 of the IC chip 1 (FIG. 8). , FIG. 9).

FIG. 17 is a block diagram showing a data transmission system between the non-contact communication type information carrier 31, reader / writer 32 and host computer 44 according to the present invention. The information carrier 31 includes the antenna coil 3 and the power generation circuit 3
3, a memory 34, a control circuit 35, and the like. The reader / writer 32 includes an antenna coil 36 corresponding to the antenna coil 3 on the information carrier 31 side, a transceiver / receiver 37, a controller 38, and the like. The relationship between the parts is as shown in the figure.

FIG. 18 shows the antenna coil 3 of the information carrier 31.
FIG. 4 is a diagram showing a correspondence relationship between the antenna coil of the reader / writer 32 and the antenna coil 36 of the reader / writer 32. The antenna coil 36 is wound around a cylindrical ferrite core 39 having a lower surface substantially the same as the outer shape of the antenna coil 3. Then, the axial direction of the ferrite core 39 is arranged perpendicular to the plane of the antenna coil 3, and the lower surface of the ferrite core 39 approaches the antenna coil 3.

Token 1 attached to reader / writer 32
3 is positioned by guide means (not shown) so that the center of the token 13 (the center of the antenna coil 3) coincides with the center of the lower surface of the ferrite core 39. Regardless of the orientation above, the antenna coil 3 and the antenna coil 36 are electromagnetically coupled to exchange data.

FIG. 19 is a diagram showing a third embodiment of the present invention. In this example, a circular fitting concave portion 14 is formed inside a case 42 for accommodating various test objects 41 such as a DNA chip, a test tube, and a test piece.
The core piece 11 is fitted in the fitting recess 14 so that the core piece 11 faces the outside of the case 42 (not shown). Core piece 1
Various data related to the inspection object 41 are stored in the memory 1, and data is exchanged between the antenna coil 3 on the core piece 11 side and the antenna coil 36 on the reader / writer side via the wall of the case 42. . Therefore, in this embodiment, the case 42 itself is a non-contact communication type information carrier.

FIG. 20 is a diagram showing a fourth embodiment of the present invention. In the present embodiment, the core piece 11
The example which embedded is shown. The card 43 has the same shape 2
It is configured by laminating two card halves via a core piece 11. The core piece 11 is installed at an intermediate position between two opposing long sides 43a and 43b of the card 43 and near the insertion direction X into the reader / writer.

FIG. 21 is a view showing a fifth embodiment of the present invention. The difference between the fourth embodiment and the fourth embodiment is that the core piece 11 is installed at a middle position between the two opposing short sides 43c and 43d of the card 43 and near the insertion direction X into the reader / writer. It is a point.

FIG. 22 is a view showing a sixth embodiment of the present invention. The present embodiment is different from the fourth embodiment in that the core piece 11 is provided at the center of the card 43.

The integration of the core piece 11 and the card 43 is as follows.
The card may be integrally formed including the core piece fitting concave portion by an injection molding method or the like instead of the two laminated shapes, and the core piece may be fitted into the fitting concave portion later.

In the above-described embodiment, the caulked portion is formed in the core piece main body, and thereby the IC chip is carried in the concave portion. However, the IC chip may be simply fitted and carried in the concave portion without forming the caulked portion. It is possible.

The non-contact communication type information carrier according to the present invention comprises the token, card, DNA chip,
The present invention is not limited to the case where various test objects such as test tubes and test pieces are stored, but can be applied to various industrial fields.

For example, a connector part of an electronic card conforming to a PC card standard, a compact flash (registered trademark) standard, or the like.
Small areas that are not applicable up to now, such as frame parts / case parts, tip parts of pen-type pointing devices, junction connectors for LAN cables and optical cables, keys for automobiles, cases of optical disks / magnetic disks / tape media, and media themselves. It is possible to realize an application by embedding in a file.

[0050]

According to the first aspect of the present invention, a coil forming surface can be protected by mounting an IC chip integrally formed with an antenna coil in a recess of a core piece main body.
In addition, since the size can be easily handled, bagging or supply by a parts feeder becomes possible, and an inexpensive non-contact communication type information carrier having good handleability and productivity can be provided.

Even if the types, shapes, specifications, etc. of the information carriers are different, the same core piece can be used in common and the cost can be reduced by keeping the shape of the attachment portion (attachment portion) to the core piece constant.

According to a second aspect of the present invention, a circular recess is formed in the core piece main body, the square IC chip is inserted into the recess, and the periphery of the opening of the recess is caulked inward.
Since the IC chip is carried in the concave portion by the caulking portion, fixing of the IC chip in the concave portion is simple.

According to a third aspect of the present invention, the IC chip is arranged in the recess so that the antenna coil faces the bottom of the core piece body, and the bottom of the core piece body is arranged on the surface side of the information carrier. Since the core piece is attached to the information carrier and the bottom surface of the core piece main body does not protrude from the surface of the information carrier, the coil forming surface can be protected, and at the time of handling the information carrier (for example, taking the information carrier in and out of the reader / writer) At that time, the information carrier is not caught by the core piece, and the handling is smooth.

According to a fourth aspect of the present invention, the antenna coil is formed on the IC chip so that the IC chip is square and the winding center of the antenna coil substantially coincides with the center of the IC chip. A circular recess is formed at the position, the diameter of which is substantially equal to the diagonal length of the IC chip,
An IC chip is mounted in the recess to form a core piece, and the core piece is mounted on a fitting portion of the information carrier. Therefore, it is not necessary to consider the directionality when mounting the small IC chip on the core piece main body, and the mounting process of the IC chip is simplified, and the productivity can be improved.

According to a fifth aspect of the present invention, the non-contact communication type information carrier has a disk shape, and a circular insertion recess is formed at a center position of the disk information carrier. The core piece is attached to the. For this reason, it is possible to realize a user-friendly non-contact communication type information carrier which does not need to consider the direction of insertion into the reader / writer device at the time of use at low cost.

According to the present invention, the base material of the core piece and the non-contact communication type information carrier is made of plastic, and the material of the core piece is selected to be harder than the material of the non-contact communication type information carrier. Thereby, when the core piece is fitted into the concave portion of the information carrier main body or when a stress is generated at the time of use after the fitting, the stress applied to the IC chip is relieved, so that chip cracking and circuit breakage of the IC chip can be avoided. It becomes possible.

According to a seventh aspect of the present invention, the non-contact communication type information carrier is a case for storing various test objects such as a DNA chip, a test tube, and a test piece. This makes it possible to provide a low-cost case in which the positioning in the non-contact communication is ensured and the inspection target can be managed.

According to the present invention, the core piece body is made of a transparent or translucent material.
It is convenient to check whether or not the chip is attached.

[Brief description of the drawings]

FIG. 1 is a plan view of a core piece for a non-contact communication type information carrier according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is an enlarged perspective view of an IC chip integrally formed with an antenna coil used for the core piece.

FIG. 4 is an enlarged plan view of the IC chip.

FIG. 5 is a plan view for explaining a step of mounting the IC chip on a core piece main body.

FIG. 6 is a cross-sectional view for explaining a step of mounting the IC chip on a core piece main body.

FIG. 7 is a sectional view showing a modification of the core piece for a non-contact communication type information carrier.

FIG. 8 is a plan view showing a state before the core piece is mounted on the token.

FIG. 9 is a plan view showing a state after the core piece is mounted on the token.

FIG. 10 is an enlarged sectional view taken on line 9B-B of FIG. 9;

FIG. 11 is a plan view of an IC chip for a non-contact communication type information carrier according to a second embodiment of the present invention.

FIG. 12 is an enlarged view of a part shown in FIG. 11C.

FIG. 13 is a plan view of a core piece main body used for the non-contact communication type information carrier.

FIG. 14 is a front view in which a part of the core piece main body is cut.

FIG. 15 is a plan view of a core piece.

FIG. 16 is a front view in which a part of the core piece is cut.

FIG. 17 is a block diagram showing a data transmission system of a non-contact communication type information carrier, a reader / writer, and a host computer.

FIG. 18 is a perspective view showing a correspondence between an antenna coil on the information carrier side and an antenna coil on the reader / writer side.

FIG. 19 is a sectional view of a case (non-contact communication type information carrier) according to a third embodiment of the present invention.

FIG. 20 is a plan view of a card (a non-contact communication type information carrier) according to a fourth embodiment of the present invention.

FIG. 21 is a plan view of a card (non-contact communication information carrier) according to a fifth embodiment of the present invention.

FIG. 22 is a plan view of a card (non-contact communication information carrier) according to a sixth embodiment of the present invention.

[Explanation of symbols]

1: IC chip, 1a to 1d: corner of IC chip, 3:
Antenna coil, 5: core piece body, 6: recess, 7:
Caulking allowance, 8: ultrasonic welding horn, 9: caulking part, 1
0: adhesive, 11: core piece, 12: bottom, 13: token, 14: fitting recess, 31: non-contact communication information carrier, 42: case, 43: card, D: diameter of recess of core pis body, L: Diagonal length of IC chip, O1: I
Center of C chip, O2: Center of winding of antenna coil, O
3: The center of the core pis, O4: The center of the token

Continued on the front page (72) Inventor Kazuhiko Omichi 1-88 Ushitora, Ibaraki-shi, Osaka F-term in Hitachi Maxell, Ltd. (Reference) 2C005 MA09 MA19 MB06 MB07 NA09 RA22 5B035 AA08 BA03 BA04 BA05 BB09 CA01 CA03 CA23 5J047 AA01 AA02 AA05 AA07 AA09 AA10 AB11 EF04 EF05

Claims (8)

[Claims] An IC chip integrally formed with an antenna coil on one surface is mounted in a recess of a core piece body to form a core piece, and the core piece is mounted at a predetermined position on a non-contact communication type information carrier. Non-contact communication type information carrier. 2. The non-contact communication type information carrier according to claim 1, wherein a circular concave portion is formed in the core piece main body,
A non-contact communication type information carrier, wherein the square IC chip is inserted into the concave portion, the periphery of the opening of the concave portion is caulked inward, and the IC chip is carried in the concave portion by the caulked portion. 3. The non-contact communication type information carrier according to claim 1, wherein the IC chip is arranged in the concave portion such that the antenna coil faces the bottom of the core piece main body, and the bottom of the core piece main body is a surface of the information carrier. A non-contact communication type information carrier, wherein a core piece is attached to an information carrier so as to be disposed on a side, and a bottom surface of the core piece main body does not protrude from a surface of the information carrier. 4. The non-contact communication type information carrier according to claim 1, wherein the IC chip is square, and the antenna coil is formed on the IC chip such that the winding center of the antenna coil substantially coincides with the center of the IC chip. A circular recess having a diameter substantially equal to the length of the diagonal line of the IC chip was formed at the center position of the core piece main body, and the IC chip was mounted in the recess to form a core piece, and the core piece was mounted on the information carrier. A non-contact communication type information carrier characterized by the above-mentioned. 5. The non-contact communication type information carrier according to claim 4, wherein the non-contact communication type information carrier has a disk shape, and a circular fitting recess is formed at a center position of the disk-shaped information carrier. A non-contact communication type information carrier, wherein the core piece is mounted in the fitting recess. 6. The non-contact communication information carrier according to claim 1, wherein a base material of the core piece and the non-contact communication information carrier is made of plastic, and a material of the core piece is a non-contact communication information carrier. A non-contact communication type information carrier characterized by being a material which is harder than the material of (1). 7. The non-contact communication information carrier according to claim 1, wherein the non-contact communication information carrier is a case for storing an inspection object. 8. The non-contact communication type information carrier according to claim 1, wherein the core piece main body is made of a transparent or translucent material.