JPS6328449Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a liquid crystal display in which a circuit element and a liquid crystal display element are disposed on both sides of a circuit board and are electrically connected to each other.

[Technical background of the invention and its problems]

Various mounting methods have been proposed in the past for attaching electronic components to the circuit boards that make up electronic devices and connecting each component to each other, but in general, the aim is to make effective use of the space in the storage container and downsize the device. In order to measure this, it is preferable to arrange and fix electronic components on both sides of a circuit board, and to interconnect the input and output terminals of each component.

Figures 1 and 2 show the mounting structure when using a through-hole board, which is effective for arranging electronic components on both sides of the board and connecting each component to each other. This will be explained below using a clock as an example.

In the figure, 1 is a through-hole board for mutually connecting and fixing an IC chip and a display element forming a drive circuit, 2 is a circuit component that is connected and fixed to one side of the board 1, and 3 is a through-hole board that is fixed to the other side of the board 1. The circuit component 2 is soldered to the electric path formed on the surface of the substrate, the liquid crystal display element 3 is placed on the illumination light guide 4 with a transflective plate sandwiched between them, and the circuit component 2 is mounted on the substrate 1. The cell case 5 that is locked is fixed by sandwiching the conductive rubber 6 that connects to the circuit section.

In this case, the connection between the liquid crystal display element 3 and the circuit component 2 is made by soldering the lead pin 2b of the drive IC 2a to the exposed terminal connected to the through hole 1a of the substrate 1, and making an electrical connection with the electric path 1b formed on the other side. , with a conductive rubber 6 interposed therebetween to form a drive signal path.

By the way, the diameter of the through hole 1a needs to be large enough to insert the lead of the element, and furthermore, since a certain distance is required between each hole hole position to prevent contact between the terminals, the number of outputs of the lead pin 2b of the drive IC 2a is When the number of through holes 1a increases, the area occupied by the through holes 1a increases, which has the disadvantage that the board 1 becomes larger compared to the area required for arranging the circuit components 2. It has the problem of providing constraints.

[Purpose of invention]

In this invention, by bending and attaching a flexible printed board to cover both sides of an insulating base substrate, electronic components arranged and fixed on one side and liquid crystal display elements positioned and fixed on the other bent side can be mutually connected. The object of the present invention is to provide an electrical connection structure for a liquid crystal display device that facilitates connection and enables high-density wiring on a circuit board with a minimum area required for arranging components.

[Summary of the idea]

The present invention forms a flexible printed board consisting of a base attached to the surface of the base substrate and a pair of bent parts bent to the back of the substrate, and electrode terminals of the liquid crystal display element are attached to the ends of the bent parts. In addition to forming a terminal part to be connected to the flexible printed board, the liquid crystal display element is connected via conductive rubber, and electrical connection is made with high density to the electronic components connected to the base of the flexible printed board, and an extremely small unit is formed. It is characterized by having been configured.

[Example of idea]

In FIG. 3, reference numeral 10 denotes an insulating base substrate made of ceramic or baked plate, etc., and a notch is provided at its periphery for use in positioning the substrate in a storage case (not shown). Reference numeral 11 denotes a flexible printed board, which is attached to one side of the base board 10 and has a base 11 on which electronic components are arranged and fixed.
A bent portion 11B is bent toward the back side at the edge of the substrate 10 and has a connecting terminal exposed from the base side at the end thereof.
Consisting of

Now, if we were to arrange the timekeeping circuit and liquid crystal display element 12 for a digital watch, the base 11A of the flexible printed board 11 would have an IC terminal 11a to which the lead pin 13a of the watch drive IC 13 is connected, and a correction switch or chip. A terminal 11b to which a capacitor or the like is connected is formed to be exposed, and a terminal 11c for the liquid crystal display element 12 is formed in the bent portion 11B, extending from the drive signal output portion of the IC terminal 11a in a fan shape on the bent surface. .

Figures 4A and 4B show external views when the flexible printed board 11 is bent and attached to the base board 10, ensuring only the necessary area for arranging circuit components such as the watch drive IC 13. This eliminates the need to increase the size of the substrate for wiring due to the area occupied by the through holes shown in FIG. 1 or 2, and provides an extremely effective electrical connection structure for small-sized liquid crystal display devices.

FIG. 5 shows a cross-sectional view of a digital watch display unit when circuit components such as the watch drive IC 13 and the liquid crystal display element 12 are arranged and fixed using the circuit board of the present invention.
Flexible printed board 11 bent and attached to 0
Timing circuit components such as a drive IC 13 are arranged and fixed on the base 11A of the terminal 11C of the bent portion 11B.
Electrode terminals of the liquid crystal display element 12 are connected to the electrode terminals of the liquid crystal display element 12 via conductive rubber 14 . The liquid crystal display element 12 is connected to a clock circuit by a conductive rubber 14 and is clamped and fixed by a cell case 15.
An elastic arm 15a that engages with the notch of the base substrate 10 is integrally formed on the outer periphery of the elastic arm 15a, which has a locking claw 15b at its tip, and the light guide plate 16 for night illumination of the liquid crystal display element 12 is attached to the elastic arm 15a. It is configured to be placed at the back and fixed at the same time.

[Effect of idea]

As is clear from the above structure, according to the present invention board, the flexible printed board 11 is bent and adhered to both sides of the base board, making it possible to interconnect the liquid crystal display element and electronic components disposed on both sides. , the size of the board can be determined by the maximum area occupied by the components arranged on both sides of the board, there is no wasteful expansion of the area occupied by wiring, and it is also possible to form copper foil for double-sided boards and to reduce the drilling process as in through-hole boards. It can be made as a low-cost board, and there is no risk of breakage of the connection line due to peeling off of the copper foil such as through holes, and the connection configuration with a pair of bent parts allows for high wiring density.
The electrical connection structure can be extremely effective in downsizing the device.

Although the above-mentioned embodiment has been described as a watch display unit in which electronic components are arranged on one side of a circuit board and a liquid crystal display element connected to this is arranged on the other side, there are various types of liquid crystal display elements. Needless to say, this effect becomes more pronounced especially when the number of interconnections between components arranged on both sides is diverse, such as when a high-density electrode pattern is used to switch and display information.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a conventional example of a display unit that connects a liquid crystal display element and a display drive circuit, Fig. 2 is a sectional view showing how the unit is assembled, and Fig. 3 is an exploded perspective view showing a conventional example of a display unit that connects a liquid crystal display element and a display drive circuit. FIG.
Figures A and B are perspective views showing how electric circuits are formed on the front and back surfaces of the same substrate, and FIG. 5 is a sectional view showing how a display unit using the same board is assembled. 10... Insulating base board, 11... Flexible printed board, 11A... Base, 11B...
Bending portion, 12...Liquid crystal display element, 13...Circuit component.

Claims (1)

[Scope of utility model registration request] A flexible printed board formed by continuously forming a base portion attached to the surface of an insulating base substrate, and a pair of bent portions bent at opposing edges of the base substrate and attached to the back surface of the base substrate. A terminal section for arranging and connecting electronic components is formed on the base surface of the flexible printed board, an electric path is provided extending at least from this terminal section to a pair of bent sections, and a liquid crystal display is provided at the end of the bent section. 1. An electrical connection structure for a liquid crystal display device, characterized in that a terminal portion for connection with an electrode terminal of an element is formed, and a liquid crystal display element is connected to the connecting terminal portion with a conductive rubber interposed therebetween.