TWI877715B - Key structure - Google Patents

Abstract

A key structure includes a keycap, a connecting assembly and a circuit board. One end of the connecting assembly connects to the keycap. The circuit board includes an upper layer membrane, a middle layer substrate, a lower layer membrane and a hook. The middle layer substrate includes a first insulating surface and a second insulating surface. The first insulating surface connects to the upper layer membrane. The lower layer membrane connects to the second insulating surface of the middle layer substrate. The hook at least connects to the middle layer substrate. The hook passes through the upper layer membrane and extends toward the keycap. Another end of the connecting assembly connects to the hook.

Description

Key structure

The present invention relates to a key structure, and in particular to a key structure used in a membrane keyboard.

In terms of current computer usage habits, the keyboard is one of the indispensable input devices. Both the computer itself and its peripheral products are developing towards the design concept of light, thin, short and small. The keyboard has also changed from the early large structure to a thin keyboard. Thin keyboards usually use a film circuit board, also known as a membrane keyboard. The main components of a membrane keyboard include a base plate, a film circuit board and keys. Generally speaking, the film circuit board is arranged above the base plate. The keys mainly include a connecting component and a key cap. The base plate has a hook for connecting components. Therefore, one end of the connecting component is connected to the key cap, and the other end is connected to the hook on the base plate. When a button is pressed, the thin film circuit board is triggered to generate a corresponding trigger signal.

Since the bottom plate is a component for connecting and supporting the keys, the bottom plate is often made of a high-strength metal member, such as a metal plate. However, the use of the bottom plate makes the overall weight of the keyboard heavier and also has a certain thickness. Therefore, the conventional membrane keyboard still has room for improvement.

In view of the above problems, the main purpose of the present invention is to provide a key structure, which solves the weight and thickness problems of the conventional membrane keyboard by means of a novel design of a circuit board including a hook.

To achieve the above-mentioned purpose, the present invention provides a key structure, which includes a key cap, a connecting assembly and a circuit board. One end of the connecting assembly is connected to the key cap. The circuit board includes an upper film, a middle substrate, a lower film and a hook. The middle substrate includes a first insulating surface and a second insulating surface opposite to each other. The first insulating surface is connected to the upper film. The lower film is connected to the second insulating surface of the middle substrate. The hook is at least connected to the middle substrate. The hook passes through the upper film and extends toward the key cap, and the other end of the connecting assembly is connected to the hook.

According to one embodiment of the present invention, the hook further connects the upper film and the lower film.

According to an embodiment of the present invention, the upper film includes a first opening, the middle substrate includes a second opening, the lower film includes a third opening, the first opening, the second opening and the third opening together form a through hole, and a bottom of the hook is disposed in the through hole.

According to one embodiment of the present invention, the diameters of the first opening and the third opening are larger than the diameter of the second opening.

According to one embodiment of the present invention, the hook is manufactured by insert injection molding, and the bottom of the hook is formed in the through hole.

According to an embodiment of the present invention, the middle substrate and the hook are formed together by stamping. In addition, one end of the hook is connected to the middle substrate, and the other end faces the key cap.

According to one embodiment of the present invention, the upper film includes a first opening, and the hook passes through the first opening toward the connecting assembly and the key cap.

According to one embodiment of the present invention, the lower film is a closed plate.

According to an embodiment of the present invention, the middle substrate is a metal plate, and an insulating paint is applied to two opposite surfaces of the metal plate to form a first insulating surface and a second insulating surface.

According to an embodiment of the present invention, the upper film and the lower film are respectively a plastic plate.

According to an embodiment of the present invention, the middle substrate includes a hollow portion. The upper film includes an upper conductive circuit disposed on a surface of the upper film facing the middle substrate. The lower film includes a lower conductive circuit disposed on a surface of the lower film facing the middle substrate. The upper conductive circuit and the lower conductive circuit correspond to the hollow portion.

As mentioned above, according to the key structure of the present invention, the circuit board includes an upper film, a middle substrate, a lower film and a hook. The middle substrate includes a first insulating surface and a second insulating surface opposite to each other. In addition, the hook is at least connected to the middle substrate. The hook passes through the upper film and extends in the direction of the key cap so that the connecting component can be connected to the hook. When the key cap is pressed, the middle substrate can provide the main supporting force without the need to set up a base plate separately. In other words, in addition to the function of the circuit board itself, the circuit board of the present invention can also directly replace the base plate of the known keyboard. Therefore, a keyboard that uses the key structure of the present invention can reduce its overall weight and thickness to meet the design concept of lightness and thinness.

In order to better understand the technical content of the present invention, a preferred specific embodiment is described as follows.

FIG. 1 is an exploded schematic diagram of the key structure of the first embodiment of the present invention, FIG. 2 is a schematic diagram of the assembled circuit board shown in FIG. 1, and FIG. 3 is a schematic diagram of the assembled key structure shown in FIG. 1. Please refer to FIG. 1, FIG. 2 and FIG. 3. In this embodiment, the key structure 1 includes a circuit board 10, a connecting component 20 and a key cap 30. Among them, the key structure 1 can be applied to a film keyboard, so the circuit board 10 is a film circuit board (or film switch circuit board) with a three-layer structure. In this embodiment, the circuit board 10 includes an upper film 11, a middle substrate 12, a lower film 13 and a hook 14. Taking FIG. 1 as an example, the three-layer structure of the circuit board 10 is, from top to bottom, an upper film 11, a middle substrate 12, and a lower film 13. Among them, the upper film 11 is closest to the key cap 30. The hook 14 is at least connected to the middle substrate 12. In this embodiment, the hook 14 is connected to the upper film 11, the middle substrate 12, and the lower film 13 at the same time. Moreover, the hook 14 passes through the upper film 11 and extends toward the key cap 30.

Preferably, the middle substrate 12 in this embodiment can be a metal plate, such as an iron plate, so as to increase the structural strength of the circuit board 10. Preferably, the hook 14 can be made by embedding injection. As shown in FIG1 , the upper film 11 includes a first opening 111, the middle substrate 12 includes a second opening 121, and the lower film 13 includes a third opening 131. The number of the first opening 111, the second opening 121, and the third opening 131 corresponds to the number of the hooks 14, and four are used as an example in this embodiment. When preparing the circuit board 10, the upper film 11, the middle substrate 12 and the lower film 13 may be stacked first, and the first opening 111, the second opening 121 and the third opening 131 may be aligned with each other so that the first opening 111, the second opening 121 and the third opening 131 together form a through hole H (indicated by the edge of the through hole H in FIG. 2). The upper film 11, the middle substrate 12 and the lower film 13 may be bonded to each other with glue.

Next, the stacked and bonded upper film 11, the middle substrate 12 and the lower film 13 are placed in a mold, and the hook 14 is formed at the through hole H by an embedded injection method. The bottom 141 of the hook 14 is formed in the through hole H, and the hook portion 142 is formed from the upper film 11 toward the key cap 30. In other words, the hook 14 of this embodiment includes the bottom 141 and the hook portion 142. The bottom 141 is set in the through hole H, and the hook portion 142 extends from the upper film 11 toward the key cap 30.

FIG4 is an enlarged schematic diagram of the circled area A of the key structure shown in FIG3, please refer to FIG1 and FIG4. Preferably, the apertures of the first opening 111 and the third opening 131 are larger than the aperture of the second opening 121. In other words, the apertures of the openings located in the upper film 11 and the lower film 13 (i.e., the first opening 111 and the third opening 131) are larger than the apertures of the openings located in the middle substrate 12 (i.e., the second opening 121). Therefore, when the upper film 11, the middle substrate 12, and the lower film 13 are stacked, a structure in which the middle substrate 12 protrudes toward the through hole H can be formed in the through hole H (indicated by the edge line on the inner wall of the through hole H). When the hook 14 is formed by insert molding, the protruding structure of the middle substrate 12 allows the bottom 141 to be stably disposed in the through hole H.

In addition, the hook 14 passes through the upper film 11 and extends toward the key cap 30, so that the hook 14 can be used to connect the connection assembly 20. In this embodiment, one end of the connection assembly 20 is connected to the key cap 30, and the other end is connected to the hook 14 of the circuit board 10. It should be noted that the connection assembly 20 of this embodiment is a scissor-type connection assembly, so the connection assembly 20 includes an outer frame 21 and an inner frame 22 that are hinged to each other. One end of the outer frame 21 is connected to the key cap 30, and the other end is connected to the hook 14 of the circuit board 10. Similarly, one end of the inner frame 22 is connected to the key cap 30, and the other end is connected to the hook 14 of the circuit board 10. Therefore, one end of the connection assembly 20 referred to in this embodiment can be one end of the outer frame 21 and one end of the inner frame 22. The other end of the connection assembly 20 referred to in this embodiment can be the other end of the outer frame 21 and the other end of the inner frame 22. Through the above structure, the (scissor-type) connection assembly 20 can guide the key cap 30 to rise and fall relative to the circuit board 10. When the key cap 30 is pressed, the middle substrate 12 (metal plate) with higher strength can provide the main support force.

It should be noted that the appearance of the circuit board 10 may correspond to a membrane keyboard, such as a rectangular shape, and the present figure only shows a portion of the structure of the circuit board 10 corresponding to one of the key structures 1. In addition, the number of hooks 14 shown in the present figure (i.e., four) also corresponds to the number of one of the key structures 1 (or key caps 30), which can be adjusted according to the structure of the connection assembly 20. Specifically, the connection assembly 20 of the present embodiment includes an outer frame 21 and an inner frame 22. In addition, the opposite sides of the outer frame 21 and the inner frame 22 are connected to the circuit board 10, so the circuit board 10 corresponding to each key structure 1 can have four hooks 14, as shown in Figures 1 and 2.

FIG5 is an enlarged schematic diagram of the circled area B of the key structure shown in FIG3, please refer to FIG3 and FIG5. In this embodiment, the middle substrate 12 includes a hollow portion 122, a first insulating surface 123 and a second insulating surface 124 opposite to each other. The first insulating surface 123 faces and is connected to the upper film 11, and the second insulating surface 124 faces and is connected to the lower film 13. In addition, the surfaces corresponding to the upper film 11 and the lower film 13 respectively have a conductive circuit (for example, a circuit configured with a silver paste line), which is at least partially located in the hollow portion 122. The first insulating surface 123 and the second insulating surface 124 are used to prevent the conductive circuits outside the hollow portion 122 from contacting each other.

Specifically, as shown in FIG5 , the upper film 11 includes an upper conductive circuit 112, which is disposed on a surface of the upper film 11 facing the middle substrate 12. The lower film 13 includes a lower conductive circuit 132, which is disposed on a surface of the lower film 13 facing the middle substrate 12. The upper conductive circuit 112 and the lower conductive circuit 132 correspond to the hollow portion 122. In other words, the upper conductive circuit 112 is disposed on the lower surface of the upper film 11, and is partially located in the hollow portion 122. The lower conductive circuit 132 is disposed on the upper surface of the lower film 13, and is partially located in the hollow portion 122.

Referring to FIG. 1 , FIG. 3 and FIG. 5 , the key structure 1 of the present embodiment further includes an elastic member 40. The elastic member 40 is disposed between the circuit board 10 and the key cap 30 and is located in the connection assembly 20. When the key cap 30 is pressed, the elastic member 40 presses down the upper film 11, causing the upper film 11 to deform toward the hollow portion 122, thereby causing the upper conductive circuit 112 to contact and conduct with the lower conductive circuit 132 of the lower film 13, thereby generating a trigger signal.

In order to prevent the upper conductive circuit 112 and the lower conductive circuit 132 located outside the hollow portion 122 from being connected to each other, the upper and lower surfaces of the middle substrate 12 must be made of insulating materials (i.e., the first insulating surface 123 and the second insulating surface 124). Since the middle substrate 12 in this embodiment is a metal plate, preferably, insulating paint can be applied to the two opposite surfaces of the metal plate, for example, by roller coating, to form the first insulating surface 123 and the second insulating surface 124.

In the present embodiment, the main supporting force is provided by the middle substrate 12 made of metal material, so the circuit board 10 of the present embodiment can replace the base plate of the conventional keyboard. Preferably, the upper film 11 and the lower film 13 can use a lighter material. The upper film 11 and the lower film 13 of the present embodiment are plastic films, which can be, for example but not limited to, polyethylene terephthalate (PET or PETE for short). In other embodiments, the upper film 11, the middle substrate 12 and the lower film 13 can all be plastic materials. By increasing the thickness of the middle substrate 12 to increase its strength, and forming the hook 14 by injection molding, the circuit board 10 can also replace the base plate of the conventional keyboard. In addition, in the embodiment where the middle substrate 12 is a plastic plate, its two opposite surfaces are the first insulating surface 123 and the second insulating surface 124, and there is no need to apply insulating paint separately.

Preferably, the lower film 13 is a light-transmissive material and includes a light-shielding ink 133, as shown in FIG5 . The light-shielding ink 133 is disposed on a surface of the lower film 13 away from the middle substrate 12. When a backlight module (not shown) is disposed below the key structure 1, the light-shielding ink 133 can be used to block light, and a light-transmissive area is formed where the light-shielding ink 133 is not disposed, so that light can irradiate the key structure 1 through the light-transmissive area. In this embodiment, the light-shielding ink 133 is disposed on the lower surface of the lower film 13, but the present invention is not limited thereto. In other embodiments, the light-shielding ink 133 can also be disposed on the upper surface of the lower film 13. Specifically, the lower film 13 is made of plastic material, so the light-shielding ink 133 can be formed on the lower surface or upper surface of the lower film 13 by roller coating or spraying, so that the lower film 13 can also serve as a light-shielding sheet.

FIG6 is an exploded schematic diagram of the key structure of the second embodiment of the present invention, FIG7 is a schematic diagram of the assembled circuit board shown in FIG6, FIG8 is a schematic diagram of the assembled key structure shown in FIG6, and FIG9 is an enlarged schematic diagram of the circled area C of the key structure shown in FIG8. Please refer to FIG6, FIG7, FIG8 and FIG9. The key structure 1a of this embodiment also includes a circuit board 10a, a connecting component 20, a key cap 30 and an elastic member 40. Among them, the structure and connection relationship of the connecting component 20, the key cap 30 and the elastic member 40 are the same as those of the first embodiment, so their numbers are used. In this embodiment, the circuit board 10a also includes an upper film 11a, a middle substrate 12a, a lower film 13a and a hook 14a. The main difference from the above-mentioned embodiment is that the hook 14a of this embodiment is only connected to the middle substrate 12a, but not to the upper film 11a and the lower film 13a.

In this embodiment, the middle substrate 12a and the hook 14a can be formed together by stamping and bending. One end of the hook 14a is connected to the middle substrate 12a, and the other end faces the key cap 30. Specifically, the middle substrate 12a can be a metal plate or a plastic plate. The middle substrate 12a in this embodiment is a plastic plate as an example. When preparing the middle substrate 12a and the hook 14a, the second opening 121a and the hollow part 122a and other holes can be stamped on the complete plastic plate (or metal plate), and the planar hook 14a structure is formed at the same time. Then, the planar hook 14a is bent upward to form the hook 14a protruding in the direction of the key cap 30.

In this embodiment, since the middle substrate 12a is a plastic plate, its two opposite surfaces are respectively the first insulating surface 123a and the second insulating surface 124a, as shown in FIG6 . Preferably, the thickness of the middle substrate 12a is greater than the thickness of the upper film 11a and the lower film 13a to provide better strength and support. In addition, the upper film 11a also includes an upper conductive circuit, and the lower film 13a also includes a lower conductive circuit to generate a trigger signal. The details of generating the trigger signal can be directly referred to the description of the first embodiment, and will not be elaborated here.

In this embodiment, since the hook 14a is only connected to the middle substrate 12a, the lower film 13a can be a closed film. Therefore, the lower film 13a of this embodiment is more suitable for being used as a light shielding film at the same time. The relevant content of the light shielding ink can be directly referred to the description of the first embodiment mentioned above, and will not be elaborated here.

In addition, the upper film 11a of the present embodiment also includes a first opening 111a. The hook 14a located on the middle substrate 12a can pass through the first opening 111a and extend toward the connection component 20 and the key cap 30. Compared with the first embodiment, the first opening 111a and the second opening 121a of the present embodiment are larger in area, which can reduce the overall weight of the circuit board 10a and can serve as a space for the pivot connecting the connection component 20 and the hook 14 to move downward, so as to ensure that the elastic member 40 can press down the upper film 11a to generate a trigger signal.

In summary, according to the key structure of the present invention, the circuit board includes an upper film, a middle substrate, a lower film and a hook. The middle substrate includes a first insulating surface and a second insulating surface opposite to each other. In addition, the hook is at least connected to the middle substrate. The hook passes through the upper film and extends in the direction of the key cap so that the connecting component can be connected to the hook. When the key cap is pressed, the middle substrate can provide the main supporting force without the need to set up a base plate separately. In other words, in addition to the function of the circuit board itself, the circuit board of the present invention can also directly replace the base plate of the known keyboard. Therefore, a keyboard that uses the key structure of the present invention can reduce its overall weight and thickness to meet the design concept of lightness and thinness.

It should be noted that the above embodiments are given for the purpose of illustration only, and the scope of rights claimed by the present invention should be based on the scope of the patent application, rather than being limited to the above embodiments.

1.1a: key structure 10.10a: circuit board 11.11a: upper film 111.111a: first opening 112: upper conductive circuit 12.12a: middle substrate 121.121a: second opening 122.122a: hollow part 123.123a: first insulating surface 124.124a: second insulating surface 13.13a: lower film 131: third opening 132: lower conductive circuit 133: light-shielding ink 14.14a: hook     141: bottom 142: hook 20: connection assembly 21: outer frame   22: inner frame 30: key cap 40: Elastic parts A, B, C: Circled areas H: Through hole

FIG. 1 is a schematic diagram of the exploded key structure of the first embodiment of the present invention. FIG. 2 is a schematic diagram of the assembled circuit board shown in FIG. 1. FIG. 3 is a schematic diagram of the assembled key structure shown in FIG. 1. FIG. 4 is an enlarged schematic diagram of the circled portion A of the key structure shown in FIG. 3. FIG. 5 is an enlarged schematic diagram of the circled portion B of the key structure shown in FIG. 3. FIG. 6 is a schematic diagram of the exploded key structure of the second embodiment of the present invention. FIG. 7 is a schematic diagram of the assembled circuit board shown in FIG. 6. FIG. 8 is a schematic diagram of the assembled key structure shown in FIG. 6. FIG. 9 is an enlarged schematic diagram of the circled portion C of the key structure shown in FIG. 8.

1: Button structure

10: Circuit board

11: Upper film

111: First opening

12: Middle layer substrate

121: Second opening

122: Hollow part

123: First insulating surface

124: Second insulating surface

13: Lower film

131: The third opening

14: Hook

141: Bottom

142: Hook

20:Connection components

21: External frame

22: Internal frame

30: Keycaps

40: Elastic parts

Claims (10)

A key structure includes: a key cap; a connecting component, one end of which is connected to the key cap; and a circuit board, including: an upper film, including an upper conductive circuit; a middle substrate, including a first insulating surface and a second insulating surface opposite to each other, and a hollow portion, the first insulating surface is connected to the upper film, and the upper conductive circuit is arranged on a surface of the upper film facing the middle substrate; A lower film connected to the second insulating surface of the middle substrate, the lower film including a lower conductive circuit disposed on a surface of the lower film facing the middle substrate, the upper conductive circuit and the lower conductive circuit corresponding to the hollow portion; and a hook connected at least to the middle substrate, the hook passing through the upper film and extending toward the key cap, the other end of the connection assembly connected to the hook. The key structure as described in claim 1, wherein the hook further connects the upper film and the lower film. The key structure as described in claim 2, wherein the upper film includes a first opening, the middle substrate includes a second opening, the lower film includes a third opening, the first opening, the second opening and the third opening together form a through hole, and a bottom of the hook is disposed in the through hole. A key structure as described in claim 3, wherein the diameters of the first opening and the third opening are larger than the diameter of the second opening. The key structure as described in claim 3, wherein the hook is made by embedded injection molding, and the bottom of the hook is formed in the through hole. The key structure as described in claim 1, wherein the middle substrate and the hook are formed together by stamping, and one end of the hook is connected to the middle substrate and the other end faces the key cap. A key structure as described in claim 6, wherein the upper film includes a first opening, and the hook passes through the first opening toward the connecting component and the key cap. A key structure as described in claim 6, wherein the lower film is a closed plate. The key structure as described in claim 1, wherein the middle substrate is a metal plate, and an insulating paint is applied to two opposite surfaces of the metal plate to form the first insulating surface and the second insulating surface. A key structure as described in claim 1, wherein the lower film includes a light-shielding ink disposed on a surface of the lower film away from the middle substrate.

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