Identification card

An identification card comprises a center core layer, a photograph embedded in the core layer, a first assembly of multiple layers laminated on the upper surface of the core layer and the photograph, and a second assembly of multiple layers laminated on the back surface of the core layer and the photograph. The layers of the first and second assemblies have substantially similar thermal expansion properties. Accordingly, the thickness of the identification card is uniform since the thickness of the core layer is substantially the same as the thickness of the photograph. High reliability can be obtained without any accompanying warp as a result of the substantially symmetrical arrangement of the first and second assemblies with respect to the core layer and the embedded photograph.

BACKGROUND OF THE INVENTION 
This invention relates to an identification (ID) card such as a card with a 
photograph embedded therein having a magnetic stripe, an IC (integrated 
circuit) card and the like and more particularly to an identification card 
in which the flatness and reliability of the ID card are improved. 
Conventionally, there have been laminated photographic identification cards 
(hereinafter abbreviated as photo ID card), for example, driver's 
licenses. Such cards are fabricated by affixing a photograph on the 
surface of a card substrate, and laminating a transparent overlay on the 
surface of the photograph. The card obtained is integrally formed and the 
photograph is not exposed to the air. Therefore, it is difficult to forge 
or counterfeit the card. However, the thickness of a conventional ID card 
is not uniform because of the thickness of the photograph. Therefore, 
there is a problem in that troubles arise when the thickenss of the ID 
card must be severely restricted, such as in magnetic striped cards, IC 
module integrated cards or the like. 
In another conventional ID card, a photograph is embedded in the card. 
Although, this card has a uniform thickness, the portion where the 
photograph is embedded is liable to warp during use. 
FIGS. 1 and 2 are sectional side views showing conventional photo ID cards. 
In FIG. 1, a photograph 1 is affixed on the surface of a core material 3 
of an ID card 10, and an overlay 2 is laminated on the surface of the 
photograph 1 and on the surface of the core material 3 not covered by the 
photograph 1. In this case, a portion 20 of the overlay 2 just over the 
photograph 1 is raised above the surface of the core material 3 by the 
thickness of the photograph 1. 
In FIG. 2, a photograph 1 is embedded in the inside of an ID card 11 
adjacent to a core material 3a and sandwiched between a core material 3b 
and an overlay 2. In this case, a portion 21 of overlay 2 just over the 
photograph 1 is not raised above the surface of the card 11. However, 
since the embedded position of the photograph 1 is close to the surface of 
the card 11, the card 11 could warp near the portion 21. Further, the warp 
is increased especially when manufacturing the card 11 by heating and 
pressing components of the card 11. This is because a material of the 
photograph 1, which is made of, for example, photographic paper, is 
different from that of the core material 3b, resulting in stress due to 
the differences in coefficients of thermal expansion between the different 
materials. The warp generated does not give a desirable an appearance to 
the card 11. Moreover, the conventional cards 10 and 11 are troublesome in 
use in an ID card reader or writer apparatus. 
FIG. 2 is a plan view showing a conventional magnetic stripe ID card 12. In 
FIG. 3, a magnetic stripe 6 is affixed on the upper portion of the card 
12. 
As illustrated in FIG. 3, a photograph 1 affixed on the card 12 for 
identifying an individual is made of paper or the like, with a thickness 
in the range of 100 .mu.m to 300 .mu.m. 
As mentioned above, there arise problems in that the thickness of 
conventional ID cards tends to become non-uniform and the cards are liable 
to warp when they are applied to magnetic striped cards, IC cards or the 
like. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide an 
identification card in which a photograph is embedded with high 
reliability and uniform thickness without warp. 
In order to achieve the above objects, according to the present invention, 
there is provided an identification card comprising: a core layer; a 
photograph embedded in the core layer; a first assembly of multiple layers 
laminated on the upper surface of the core layer and the photograph; and a 
second assembly of multiple layers laminated on the back surface of the 
core layer and the photograph. 
In the present invention, a photograph has a thickness which is 
substantially the same as the thickness of the core layer, and both the 
photograph and the core layer are substantially symmetrically arranged 
with respect to the two layer assemblies so that the stress exerted on 
both sides of the card is balanced to prevent warpage. Moreover, since the 
photograph is embedded deep in the card, the photograph does not create a 
bulge in the card.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will be described in detail with reference to 
presently preferred embodiments thereof as illustrated in FIGS. 4 to 7, 
where the same reference numerals as in FIGS. 1 to 3 indicate the same or 
corresponding parts. 
FIG. 4 is a sectional side view showing an identification card with an 
embedded photograph (hereinafter abbreviated as ID card) according to the 
first embodiment of the present invention. In FIG. 4, an ID card 10A is 
provided with five layers, each preferably made of material such as a 
rigid polyvinyl chloride sheet. In a center core layer 3a, a photograph 1 
is embedded and surrounded along the edges of an opening 40 made in the 
core layer 3a. A first assembly 30a of multiple layers is laminated on the 
upper surface of the photograph 1 and the core layer 3a, and a second 
assembly 31a is laminated on the back surface of the photograph 1 and the 
core layer 3a. The opening 40 has an inside size of substantially equal to 
the size of the photograph 1 for embedding the photograph 1 therein. The 
thickenss of the center core layer 3a is substantially equal to the 
thickness of the photograph 1. The first assembly 30a includes a 
transparent sheet 2b laminated directly on the upper surface of the core 
layer and photograph and a surface sheet 2a laminated on the transparent 
sheet 2b. The second assembly 31a includes an opaque material 3b laminated 
directly on the back surface of the core layer and photograph and a back 
material 4 laminated on the the opaque layer 3b. The thermal expansion of 
the first layer assembly 30a is substantially the same as that of the 
second layer assembly 31a. All of these sheet materials are laminated in 
the above manner, then heated, pressed and molded to form the integrated 
ID card 10A. A design can be disposed on the core layer 3a and opague 
layer 3b. 
In the above-mentioned ID card 10A, since the photograph 1 is embedded 
substantially in the center of the thickness of the card 10A, no bulges, 
such as portion 20 illustrated in FIG. 1, are created, and since the 
thickness of the photograph is substantially the same as the thickness of 
the core layer the thickness of the card 10A can be uniform. Further, 
although the material of the photograph 1 is different from that of the 
sheet materials, stresses on both sides of the card 10A are balanced, due 
to the symmetrical arrangement of the two assemblies having similar 
thermal expansion properties. As a result warpage is prevented in the card 
10A even after the thermal molding process thereof. 
FIG. 5 is a sectional side view showing an ID card according to the second 
embodiment of the present invention. In FIG. 5, in the same manner 
illustrated in FIG. 4, a photograph 1 is embedded generally in the middle 
of the thickness of the card 10B, and a center core layer 3a surrounds the 
photograph 1 along its edges. An opaque sheet 3c, instead of a transparent 
sheet 2b as illustrated in FIG. 4, is laminated on the center core 
material 3a. A transparent sheet 2b is disposed only above the photograph 
1 and is surrounded at its edges by the opaque sheet 3c. A surface sheet 
2a is laminated on the opaque sheet 3c and the transparent sheet 2b. In 
this embodiment, the first assemlby 30b therefore includes the surface 
material 2a, the opaque sheet 3c, and the transparent sheet 2b. On the 
other hand, a core layer 3b is laminated on the back surface of the center 
core layer 3a and the photograph 1, and a back material 4 is laminated on 
the layer 3b. In this case, the second layer assembly 31b therefore 
includes the layer 3b and the back material 4. 
In the above-mentioned card 10B, since the first and second layer 
assemblies 30b and 31b are arranged substantially symmetrically with 
respect to the photograph 1 and core layer 3a and have substantially 
similar thermal expansion properties, the stresses in both layer 
assemblies 30b and 31b are more balanced in comparison with the card 10A 
as illustrated in FIG. 4. Therefore, the generation of warpage is even 
further prevented. Moreover, since the opaque sheet 3c, except for area 
above photograph 1, is disposed on the card 10B, the card 10B has an 
improved appearance. 
FIG. 6 is a sectional side view showing an ID card according to the third 
embodiment of the present invention. In FIG. 6, a transparent sheet 2b, 
smaller in size than the photograph 1, is laminated on the photograph 1 of 
an ID card 10C. The edges of the photograph 1 are sandwiched and fixed by 
layers 3c and 3b. Other elements of the card 10C are identical to those 
of the ID card 10B as illustrated in FIG. 5. 
In the above-mentioned card 10C, the seams 50 between the photograph 1 and 
the center core layer 3a are hidden from the exterior of the card 10C, 
therefore improving the appearance of the card 10C. Moreover, positions of 
the seams 60 between the transparent sheet 2b and the layer 3c are 
different from those of the seams 50 in contrast with the card 10B 
illustrated in FIG. 5. From this reason, the strength of the card 10C can 
be improved and a highly reliable ID card can be obtained. 
FIG. 7 is a sectional side view showing an ID card according to the fourth 
embodiment of the present invention. In FIG. 7, an IC (integrated circuit) 
module 5 is built into an ID card 10D. The ID card 10D is one example of 
applying the present invention to an IC card, and is essentially the same 
as the ID card 10B illustrated in FIG. 5 except for the inclusion of the 
IC module 5. The thickness of the core layer 3a and 3b, the transparent 
sheet 2b or of other members can be selected according to requirements in 
the art. 
In the above-mentioned ID card 10D, the same effects as in the card 10B 
illustrated in FIG. 5 can be obtained. 
In the above-mentioned embodiments of the present invention, the ID cards 
are composed of five layers, however, other numbers of layers can also be 
used if the photograph is embedded generally in the center of the 
thickness of ID card. 
While presently preferred embodiments of the present invention have been 
shown and described herein, it will be apparent to those skilled in the 
art that various changes and/or modifications thereof can be made without 
departing from the spirit and scope of the invention as defined in the 
appended claims.