JP2001036207A - Circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve stresses generated between mutually connected substrates by arranging relieving parts for releasing stresses generated on connection parts, between terminals of a terminal part in which a plurality of the terminals are arranged, so as to be connected with another component composed of different kinds of materials, in a circuit board. SOLUTION: A glass substrate 9 has a prescribed coefficient of thermal expansion, and a circuit pattern 10 composed of conductive metal like Al is formed on the surface of the substrate. By forming an insulating film 11 on the circuit pattern 10, a circuit board 4 is constituted, together with a structure of an LCD. A circuit board 5 composed of a polycarbonate is connected with the circuit board 4. In the circuit board 5, not only terminals 1 are arranged in matching with terminal arrangement of terminal parts 6 of the glass substrate 9 but also comb-shaped or wedge-shaped notches as buffer parts 3, so that they are arranged to tip sides of terminal parts 2 in the circuit board 5, facing non-pattern regions 12 at the respective positions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board on which a circuit pattern of a conductive material is formed.

[0002]

2. Description of the Related Art In recent years, with the diversification of display contents on various electric appliances including consumer appliances, LCDs (Liquid Crystal Display) have been developed.
The use of a circuit board formed by forming a conductive pattern on a glass substrate or the like such as a liquid crystal display (Quid-Crystal Display) and electronic components using the circuit board are increasing, and accordingly, heterogeneous materials such as a combination of a glass substrate and a synthetic resin substrate are used. There are many examples where substrates made of material must be interconnected.

A problem in connecting substrates of such different materials is a difference in thermal expansion coefficient between the different substrates. The difference in coefficient of thermal expansion between different types of substrates causes the substrate to be weak in terms of strength, and in some cases, peeling of the joints between the substrates and peeling between the substrate and the circuit pattern may occur, thus maintaining circuit quality. It is a major obstacle in doing so.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a circuit capable of relieving a stress generated between two mutually connected substrates even when substrates of different materials are connected. The purpose is to provide a substrate.

[0005]

A circuit board according to the present invention, which has been made to solve the above-mentioned problems, has a plurality of terminals arranged in a row so as to be connected to another component made of a different material. In addition, a relief portion for releasing a stress generated in the connection portion is provided. The stress referred to here is a harmful force generated at both connection portions due to a difference in thermal expansion coefficient between substrates made of different materials. The relief portion does not necessarily need to be provided between the terminals, and may be provided as appropriate, for example, provided for every several terminals. Further, the relief portion is desirably a comb-shaped or wedge-shaped one opened at the tip end side of the terminal portion, and may be a cut-out portion of the substrate or a weakened portion. In order to avoid direct stress from being applied to the joint with the other substrate, it is desirable to set the length of the relief portion to be equal to or longer than the length of the terminal constituting the terminal portion. Note that the terminal is a portion where a conductive portion prepared for connecting to another component with solder or conductive paste is exposed.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a circuit board according to an embodiment of the present invention. FIG. 1 shows an example in which a polycarbonate circuit board 5 is connected to a glass circuit board 4 constituting an LCD. The two circuit boards 4 and 5 are joined by solder or conductive paste 8 between the terminals 7 and 1 formed on the terminal portions 6 and 2 of the two.
That is, the electrical connection and the joining of the surfaces of the terminal portions 6 and 2 with the highly insulating adhesive (not shown), that is, the physical connection are performed in parallel.

[0007] The glass substrate 9 constituting the LCD includes 1
A predetermined circuit pattern 10 having a thermal expansion coefficient of 0 ⁻⁵ / ° C. and made of a conductive metal such as Al is formed on the surface thereof, and an insulating film 11 is further formed on the circuit pattern 10 to form an LCD. A structure as a circuit pattern (circuit board 4) is provided together with the structure described above. A terminal portion 6 for connecting the LCD to other electronic components has a plurality of terminals 7 linearly arranged on an edge portion of a linearly shaped glass substrate 9. Each time a predetermined number of rows are provided, a non-pattern area 12 having a predetermined length is provided.

The circuit board 5 made of polycarbonate has a substrate body 13 having a coefficient of thermal expansion of 6 × 10 ⁻⁵ / ° C., which is larger than that of the glass substrate 9. In preparation for such a case where the substrates having a significantly different coefficient of thermal expansion are connected by heating, the circuit board according to the present invention not only has the terminals 1 arranged in line with the terminal arrangement of the terminal portions 6 of the glass substrate 9, A notch (hereinafter, referred to as a comb-shaped or wedge-shaped relief portion 3) which is open to the front end side of the terminal portion 2 of the polycarbonate circuit board 5 in a form facing the non-pattern region 12.
Notch 3 is described. ) Is provided. The notch 3 is desirably as long as possible.
In addition to making the circuit pattern 14 redundant due to the presence of, the mounting area of other electronic components may be eroded. Therefore, the length of the terminal 1 constituting the terminal portion 2 may be used as a tentative guide as the desired length of the cut 3.

The combination of the circuit boards to be connected is not limited to the combination of the glass substrate and the polycarbonate substrate, but may be a combination of a plastic printed circuit board such as ABS and a glass plate, a metal plate, a ceramic plate, or the like, or a combination of a glass substrate and a glass substrate. A combination with a ceramic substrate, or a combination of two substrates made of the same synthetic resin substrate but made of different materials is also conceivable. In practice,
In order to prevent the difference in the amount of thermal expansion from increasing at the terminal portion of the circuit board, it is desirable to provide a relaxation portion on the side having a larger thermal expansion coefficient. Needless to say, the substrate on which the relief portion can be provided includes a conventionally used epoxy resin circuit board and the like.

[0010]

As described above, when the circuit board according to the present invention is used, even when substrates of different materials are connected by heating and pressurizing, the stress generated between both the connected substrates can be reduced. In addition, the problem that a substrate having low strength is deformed, separation of a bonding portion between substrates or separation between a substrate and a circuit pattern is solved, which greatly contributes to improvement of circuit quality.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a circuit board and an LCD according to the present invention.

FIG. 2 is a sectional view showing an example of a connection state between a circuit board and an LCD according to the present invention.

[Explanation of symbols]

 1 terminal 2 terminal part 3 relaxation part

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Daiken Hagiwara 3158, Shimo-Okubo, Osawano-cho, Kamishinkawa-gun, Toyama Prefecture Inside Hokuriku Electric Industry Co., Ltd. F term (reference) in Electric Industries, Ltd. 5E317 AA04 BB01 CD31 CD34 GG09 GG20 5E344 AA02 AA22 BB02 BB04 CC05 CC07 CC11 CC19 CC25 DD02 DD06 DD13 DD14 EE16

Claims (3)

[Claims] A relief portion (3) for releasing stress generated at a connection portion between terminals of a terminal portion (2) in which a plurality of terminals (1) are arranged in order to connect with another component made of a different material. ) Provided with a circuit board. 2. The circuit board according to claim 1, wherein a length of the relaxing portion is set to be longer than a length of the terminal constituting the terminal portion. 3. The notch as claimed in claim 1, wherein the relief part has a notch open at a tip end of the terminal part.
Alternatively, the circuit board according to claim 2.