Film circuit board

Abstract

The invention relates to a thin film circuit board which comprises a layered plate structure and an additional substrate combined to the outer side of the layered plate structure. The circuit switch is arranged in a compressible space in the layered plate structure. The layered plate structure is provided with a first ventilation channel which is communicated with the compressible space. The additional substrate is provided with a second ventilation channel which is communicated with the first ventilation channel through a through hole in the layered plate structure. The second ventilation channel is also communicated with the outside of the film circuit board. Therefore, the compressible space is communicated with the outside of the thin film circuit board through the first ventilation channel, the through hole and the second ventilation channel. The compressible space is communicated with the channel outside the thin film circuit board, and the path length of the compressible space is lengthened due to the existence of the second ventilation channel, so that the opportunity that the switch contact of the circuit switch is affected by external chemical substances (such as oxidation, vulcanization and the like) can be greatly reduced.

Description

Technical Field

[0001] The invention relates to a film circuit board for a keyboard, and in particular to a film circuit board with a ventilation channel capable of adjusting pressing pressure. Background Art

[0002] The thin film circuit board of the keyboard has a layered structure. In order to inhibit the oxidation of the circuits on the thin film circuit board, the layers of the thin film circuit board are sealed in principle, but space must be left at the switch contacts to allow the corresponding switch contacts to move relative to each other to trigger the keys. The thin film circuit board usually has a ventilation channel connecting the outside and the aforementioned space, which can adjust the pressure of the aforementioned space when the user presses. In principle, the shorter the path length, the greater the chance that the corresponding switch contacts will be affected by external chemical substances (such as oxidation, sulfide, etc.). The affected switch contacts may cause the contact conduction efficiency to decrease, and in severe cases, even fail. However, in actual applications, the layout of the ventilation channel is limited by the perforated structure of the thin film circuit board (for the keycap bracket to be set) and the circuit layout, making it difficult to increase the path length of the ventilation channel, and the phenomenon that the aforementioned switch contacts are affected by external chemical substances is difficult to completely avoid. Summary of the invention

[0003] In view of the problems in the prior art, an object of the present invention is to provide a thin film circuit board, which uses an external substrate to form an extended ventilation channel to reduce the chance of internal switches being affected by external chemicals.

[0004] According to one aspect of the present invention, the present invention provides a thin film circuit board, comprising:

[0005] A layered plate structure, comprising a first circuit substrate, a second circuit substrate and an insulating layer disposed between the first circuit substrate and the second circuit substrate, the layered plate structure having a compressible space and a first ventilation channel, the first ventilation channel being formed between the first circuit substrate and the second circuit substrate, the second circuit substrate having a through hole, the first ventilation channel communicating with the compressible space and the through hole;

[0006] A circuit switch is disposed in the compressible space; and

[0007] An additional substrate is combined to the other side of the second circuit substrate relative to the insulating layer, and a second ventilation channel is formed between the additional substrate and the second circuit substrate, and the second ventilation channel is connected to the through hole and the outside of the thin film circuit board.

[0008] As an optional technical solution, the additional substrate is smaller than the second circuit substrate.

[0009] As an optional technical solution, the additional substrate is located at a corner of the second circuit substrate.

[0010] As an optional technical solution, the second ventilation channel includes a curved section, which is generally straight and includes a plurality of continuous bends.

[0011] As an optional technical solution, the plurality of continuous bends are serrated or wavy.

[0012] As an optional technical solution, the first circuit substrate, the insulating layer, the second circuit substrate and the outer substrate are stacked in a vertical direction, a circuit is arranged between the first circuit substrate and the second circuit substrate, and the circuit partially overlaps with the bending section in the vertical direction.

[0013] As an optional technical solution, the first ventilation channel is formed between the insulating layer and the second circuit substrate.

[0014] As an optional technical solution, the insulating layer is bonded to the second circuit substrate by glue.

[0015] As an optional technical solution, the additional substrate is bonded to the second circuit substrate by glue.

[0016] As an optional technical solution, the circuit switch includes two switch contacts, which are respectively arranged on the first circuit substrate and the second circuit substrate opposite to each other and are located in the compressible space.

[0017] In summary, the second ventilation channel of the present invention can be regarded as an extension of the first ventilation channel; the first ventilation channel and the second ventilation channel are channels connecting the compressible space to the outside of the thin film circuit board, and the path length thereof is obviously lengthened due to the existence of the second ventilation channel, so the chance of the circuit switch (the switch contact) being affected by external chemical substances (such as oxidation, sulfide, etc.) can be greatly reduced. In addition, from another perspective, the ventilation channel of the compressible space (including the first ventilation channel and the second ventilation channel) is three-dimensionally arranged. Compared with the conventional ventilation channel design of coplanar arrangement, the ventilation channel in the present invention also utilizes vertical space arrangement (for example, the first ventilation channel and the second ventilation channel are arranged in different planes in the vertical direction), which makes it easier to increase the path length of the ventilation channel and effectively reduces the chance of the circuit switch being affected by external chemical substances.

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but is not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 4 is a schematic diagram of a thin film circuit board according to an embodiment of the present invention.

[0020] Figure 2 for Figure 1 Exploded diagram of a thin-film circuit board.

[0021] Figure 3 for Figure 1 A cross-sectional schematic diagram showing that the first ventilation channel and the second ventilation channel of the thin film circuit board are connected.

[0022] Figure 4 for Figure 1 A top view of the configuration of the first ventilation channel and the second ventilation channel of the thin film circuit board. DETAILED DESCRIPTION

[0023] See also Figures 1 to 3 ;in, Figure 1 is a schematic diagram of a thin film circuit board according to an embodiment of the present invention, Figure 2 for Figure 1 Explosion diagram of thin film circuit board. Figure 3 for Figure 1 The thin film circuit board 1 according to one embodiment of the present invention can be applied to a device with multiple keys, such as a keyboard. For ease of explanation, the thin film circuit board 1 in the figure only shows a part of the thin film circuit board in actual application. The thin film circuit board in actual application can be equivalent to Figure 1 The thin film circuit board 1 shown in FIG. 1 is extended in the direction De (indicated by an arrow in FIG. Figure 1 In the present embodiment, the thin film circuit board 1 comprises a layered plate structure 12 and an additional substrate 14 attached to the outer side of the layered plate structure 12. The layered plate structure 12 comprises a first circuit substrate 122, a second circuit substrate 124 and an insulating layer 126 disposed between the first circuit substrate 122 and the second circuit substrate 124. The first circuit substrate 122, the insulating layer 126 and the second circuit substrate 124 are stacked together in a vertical direction Dv (indicated by a double-headed arrow in the figure). The first circuit substrate 122 and the insulating layer 126, and the insulating layer 126 and the second circuit substrate 124 are respectively combined together by glue 128a and 128b. The glue 128a and 128b can be, but are not limited to, water glue, hot melt glue, etc., for example, coated and printed on the first circuit substrate 122, the insulating layer 126 or the second circuit substrate 124. The circuit of the thin film circuit board 1 is arranged between the first circuit substrate 122 and the second circuit substrate 124, for example, arranged on the surfaces 122a and 124a of the first circuit substrate 122 and the second circuit substrate 124 opposite to each other (that is, the circuit of the thin film circuit board 1 is arranged on the surface 122a of the first circuit substrate 122 and the surface 124a of the second circuit substrate 124, and the surfaces 122a and 124a are arranged opposite to each other), and the two are separated by an insulating layer 126; wherein, to simplify the diagram lines, the circuit is not shown in the figure. The circuit includes a circuit switch 16 (only shown in Figure 3 ), by triggering the circuit switch 16 (for example, the user presses the corresponding key cap) to realize the key function.

[0024] The layered plate structure 12 has a compressible space 130 (only indicated on the left) corresponding to each circuit switch 16. Figure 3 The circuit switch 16 is disposed in the corresponding compressible space 130. The circuit switch 16 includes two switch contacts 162 (only shown in FIG. Figure 3 ), two switch contacts 162 are disposed on the first circuit substrate 122 and the second circuit substrate 124 respectively (i.e., one switch contact 162 is disposed on the surface 122a of the first circuit substrate 122, and the other switch contact 162 is disposed on the surface 124a of the second circuit substrate 124) and are located in the compressible space 130. The insulating layer 126 has a through hole 1262 (at Figure 2 The two switch contacts 162 are located at both sides of the through hole 1262 and can be brought into contact with each other through the through hole 1262 (for example, when the user presses the corresponding key cap) to trigger the circuit switch 16.

[0025] In addition, the layered plate structure 12 also has a first ventilation channel 132 (at Figure 2 , the hollowed-out portion of the glue 128b corresponding to the first ventilation channel 132 is marked), formed between the first circuit substrate 122 and the second circuit substrate 124. The first ventilation channel 132 is connected to at least one compressible space 130, whereby when the compressible space 130 is squeezed (for example, the user presses the corresponding keycap), the gas in the compressible space 130 can be discharged into the first ventilation channel 132, so that the gas pressure in the compressible space 130 is not too large; in other words, the first ventilation channel 132 has the function of adjusting the pressing pressure, which is convenient for the user to press. In this embodiment, the first ventilation channel 132 is formed between the insulating layer 126 and the second circuit substrate 124, and is mainly formed by the insulating layer 126, the second circuit substrate 124 and the glue 128b (for example, the printing area of ​​the control glue 128b), but it is not limited to this in actual operation. In actual operation, the first ventilation channel 132 can also be formed between the insulating layer 126 and the first circuit substrate 122 or formed simultaneously.

[0026] The additional substrate 14 is bonded to the other side of the second circuit substrate 124 relative to the insulating layer 126 (for example, the bottom surface 124b of the second circuit substrate 124, the bottom surface 124b and the surface 124a of the second circuit substrate 124 are two opposite surfaces of the second circuit substrate 124, that is, the layered plate structure 12 and the additional substrate 14 are stacked together in the vertical direction Dv), for example, by glue 18 (for example but not limited to water glue, hot melt glue, etc.), for example, coated and printed on the additional substrate 14 or the second circuit substrate 124. A second ventilation channel 20 (at Figure 2In the figure, the hollowed-out portion of the glue 18 corresponding to the second ventilation channel 20 is marked, which is mainly formed by the second circuit substrate 124, the additional substrate 14 and the glue 18 (for example, the printing area of ​​the control glue 18), but it is not limited to this in actual operation. The second ventilation channel 20 is connected to the outside of the thin film circuit board 1 (for example, the opening 202). The second circuit substrate 124 has a through hole 1242, which connects the first ventilation channel 132 and the second ventilation channel 20, so that the first ventilation channel 132 and the second ventilation channel 20 are connected through the through hole 1242.

[0027] In this embodiment, the second ventilation channel 20 can be logically regarded as an extension of the first ventilation channel 132; in other words, the first ventilation channel 132 and the second ventilation channel 20 are channels for the compressible space 130 to communicate with the outside of the film circuit board 1. The path length is obviously lengthened due to the existence of the second ventilation channel 20, so the chance of the circuit switch 16 (the switch contact 162) being affected by external chemical substances (such as oxidation, sulfide, etc.) can be greatly reduced. In addition, from another direction, the ventilation channel of the compressible space 130 (including the first ventilation channel 132 and the second ventilation channel 20) is arranged in a three-dimensional manner. Compared with the conventional ventilation channel design of coplanar arrangement, the ventilation channel in this embodiment also utilizes vertical space arrangement (for example, the first ventilation channel 132 and the second ventilation channel 20 are arranged in different planes in the vertical direction Dv), which makes it easier to increase the path length of the ventilation channel and effectively reduce the chance of the circuit switch 16 being affected by external chemical substances.

[0028] See also Figure 4 , Figure 4 for Figure 1 A top view of the configuration of the first ventilation channel and the second ventilation channel of the thin film circuit board; wherein the contour projections of the compressible space 130 and the first ventilation channel 132 are drawn with thin solid lines, the contour projection of the second ventilation channel 20 is drawn with dotted lines, and the contour projection of the external substrate 14 is drawn with chain lines. In this embodiment, the first ventilation channel 132 is limited by the circuit layout and mostly extends in a straight line (including multiple connected straight line segments); the second ventilation channel 20 is not limited by the circuit layout, so it can be bent and extended to increase the path length. In this embodiment, the first ventilation channel 132 includes a curved section 1322 (marked with a dotted box in Figure 2 and Figure 4 ), the curved section 1322 is adjacent to the through hole 1242; and the second ventilation channel 20 includes a plurality of curved sections 204 (selected by a dotted line frame and marked in Figure 2 and Figure 4 The curved section 204 is straight as a whole and includes a plurality of continuous bends 204a. On the other hand, the curved section 204 is equivalent to a sawtooth or wave shape in terms of structural logic. The above description of the curved section 204 is also applicable to the curved section 1322 and will not be repeated.

[0029] In addition, in this embodiment, since there is no circuit layout between the additional substrate 14 and the bottom surface 124b of the second circuit substrate 124, the second ventilation channel 20 can have more curved sections 204 relative to the first ventilation channel 132. On the other hand, the circuit in the layered plate structure 12 partially overlaps with at least one curved section 204 in the vertical direction Dv.

[0030] In addition, in this embodiment, although the external substrate 14 is smaller than the second circuit substrate 124 (that is, the external substrate 14 covers part of the bottom surface 124b of the second circuit substrate 124), the second ventilation channel 20 may have more curved sections 204, so that the path length of the second ventilation channel 20 is easily increased. However, this is not limited to the actual operation. For example, the size of the external substrate 14 can be increased to cover the entire bottom surface 124b. In addition, in actual operation, the relative position of the external substrate 14 on the bottom surface 124b can be designed according to the actual product specifications. In actual applications, the external substrate 14 is usually located between the second circuit substrate 124 and the bottom shell of the keyboard. The setting of the external substrate 14 can avoid the structure of the inner bottom shell of the keyboard (such as reinforcing ribs, screw holes, etc.) or other components (and combined with the second circuit substrate 124). In this embodiment, the external substrate 14 is located in a corner of the second circuit substrate 124 (with Figure 4 From a perspective, this is the lower right corner).

[0031] The thin film circuit board of the present invention has a layered plate structure with a compressible space and a first ventilation channel. The second ventilation channel is formed between the external substrate and the second circuit substrate. The second ventilation channel can be regarded as an extension of the first ventilation channel, which can greatly reduce the chance of the circuit switch being affected by external chemicals. In addition, the ventilation channel of the present invention is arranged in a vertical space, which makes it easier to increase the path length of the ventilation channel and reduce the chance of the circuit switch being affected by external chemicals.

[0032] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A thin film circuit board, characterized in that: Include: A layered plate structure, comprising a first circuit substrate, a second circuit substrate and an insulating layer disposed between the first circuit substrate and the second circuit substrate, the layered plate structure having a compressible space and a first ventilation channel, the first ventilation channel being formed between the first circuit substrate and the second circuit substrate, the second circuit substrate having a through hole, the first ventilation channel communicating with the compressible space and the through hole; A circuit switch is disposed in the compressible space; as well as An additional substrate is combined to the other side of the second circuit substrate relative to the insulating layer, and a second ventilation channel is formed between the additional substrate and the second circuit substrate, and the second ventilation channel is connected to the through hole and the outside of the thin film circuit board.

2. The thin film circuit board according to claim 1, characterized in that: The additional substrate is smaller than the second circuit substrate.

3. The thin film circuit board according to claim 2, characterized in that: The additional substrate is located at a corner of the second circuit substrate.

4. The thin film circuit board according to claim 1, characterized in that: The second ventilation channel includes a curved section, which is generally straight and includes a plurality of continuous bends.

5. The thin film circuit board according to claim 4, characterized in that: The plurality of continuous bends are in a sawtooth or wave shape.

6. The thin film circuit board according to claim 4, characterized in that: The first circuit substrate, the insulating layer, the second circuit substrate and the outer substrate are stacked in a vertical direction. A circuit is arranged between the first circuit substrate and the second circuit substrate. The circuit and the bent section are partially overlapped in the vertical direction.

7. The thin film circuit board according to claim 1, characterized in that: The first ventilation channel is formed between the insulating layer and the second circuit substrate.

8. The thin film circuit board according to claim 7, characterized in that: The insulating layer is bonded to the second circuit substrate by glue.

9. The thin film circuit board according to claim 1, characterized in that: The additional substrate is bonded to the second circuit substrate by glue.

10. The thin film circuit board according to claim 1, characterized in that: The circuit switch comprises two switch contacts, which are respectively arranged on the first circuit substrate and the second circuit substrate opposite to each other and are located in the compressible space.

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