Thin film circuit board
By setting a high-resistance first carbon ink contact in the switching area of the thin-film circuit board, the problem of existing keyboards being prone to ghost keys is solved, and the effect of efficiently preventing ghost keys is achieved.
Patent Information
- Application Number
- CN202311032621.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-16
- Publication Date
- 2025-02-21
AI Technical Summary
Existing keyboards are prone to ghost key phenomena when multiple keys are pressed at the same time, resulting in misjudgment. The method of using diodes to prevent ghost key phenomena is high and the process is complicated.
A thin film circuit board is designed, by setting a high resistance first carbon ink contact in the switching area as a contact, when the high resistance contact contact contact contact contact with another contact, a matrix signal with a specific high impedance value will be generated for the processor to identify. This effectively prevents ghost key phenomenon.
It effectively prevents ghost key phenomena without increasing costs and complex processes and ensures the accuracy of keyboard input.
Smart Images
Figure CN119495520A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a thin film circuit board, and in particular to a thin film circuit board for preventing ghost keys. Background Art
[0002] As technology advances with each passing day, the booming development of electronic devices has brought many conveniences to human life, so how to make the operation of electronic devices more user-friendly is an important issue. Common input devices of electronic devices include mouse devices, keyboard devices, and trackball devices, among which keyboard devices allow users to directly input text and symbols into the computer, so they are quite important.
[0003] Generally speaking, the main design of a keyboard is to arrange multiple key structures into a matrix form, which is also called a keyboard matrix. When a user presses one of the keys, the keyboard controller scans the columns and rows and receives corresponding signals of the rows and columns to identify which key is pressed.
[0004] However, the key states of the keyboard matrix affect each other. If the user presses multiple keys at the same time, the keyboard controller may make a misjudgment. For example, when the user presses multiple nearby keys at the same time, another nearby key that is not pressed may be misjudged as being pressed and turned on. This misjudged key can be called a ghost key. In order to prevent the ghost key phenomenon from occurring, a diode can be set near each key contact. The diode can make the current in the membrane switch circuit flow in only one direction. However, the disadvantage of setting a diode near each key contact is that the cost is too high and the process is too complicated. Summary of the invention
[0005] The object of the present invention is to provide a thin film circuit board to solve at least one of the above problems.
[0006] The present invention provides a thin film circuit board having at least one switch area. The thin film circuit board comprises a first film, a second film, a spacer layer, a first carbon ink contact and a corresponding contact. The second film is located above the first film. The spacer layer is located between the first film and the second film, and has an opening in the at least one switch area. The first carbon ink contact is arranged on one of a portion of the corresponding opening on the upper surface of the first film and a portion of the corresponding opening on the lower surface of the second film. The corresponding contact corresponds to the first carbon ink contact and is arranged on the other of the portion of the corresponding opening on the upper surface of the first film and the portion of the corresponding opening on the lower surface of the second film, wherein the corresponding contact is a second carbon ink contact or a conductive contact, and the resistance of the conductive contact is less than the resistance of the first carbon ink contact.
[0007] In some embodiments of the present invention, the thin film circuit board has multiple switching areas and peripheral areas surrounding the multiple switching areas, and no carbon ink material is arranged on another part of the upper surface of the first film in the peripheral area and another part of the lower surface of the second film in the peripheral area.
[0008] In some embodiments of the present invention, the thin film circuit board further includes: a first conductive wire connected to the first carbon ink contact.
[0009] In some embodiments of the present invention, the first carbon ink contact includes a main pattern and a connection pattern connected to the main pattern, and the connection pattern is also connected to the first conductive line.
[0010] In some embodiments of the present invention, one end of the first conductive wire overlaps the first carbon-ink contact.
[0011] In some embodiments of the present invention, the first conductive wire does not surround the first carbon ink contact.
[0012] In some embodiments of the present invention, the first conductive wire surrounds at least a portion of the first carbon ink contact.
[0013] In some embodiments of the present invention, the corresponding contact is a second carbon ink contact, and the thin film circuit board further includes: a second wire connected to the second carbon ink contact.
[0014] In some embodiments of the present invention, the corresponding contact is a conductive contact including a first portion and a second portion, and a gap is separated from the first portion.
[0015] In some embodiments of the present invention, the corresponding contact is a conductive contact, and two ends of the conductive contact are separated by a gap. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The following will be read in conjunction with the accompanying drawings, and various aspects of the present invention may be best understood based on the following embodiments. However, it should be understood that, in accordance with industry practice, the various features are not necessarily drawn to scale. In fact, for the sake of clarity, the shapes of the various features may be appropriately adjusted, and the sizes of the various features may be increased or decreased at will.
[0017] Figure 1 FIG. 4 is a schematic diagram of a three-dimensional exploded view of a thin film circuit board according to an embodiment of the present invention.
[0018] Figure 2 FIG. 4 is a schematic top view of a first film, a first carbon ink contact, and a first conductive line according to an embodiment of the present invention.
[0019] Figure 3 FIG. 4 is a schematic diagram of a three-dimensional exploded view of a thin film circuit board according to an embodiment of the present invention.
[0020] Figure 4FIG. 4 is a schematic diagram of a three-dimensional exploded view of a thin film circuit board according to an embodiment of the present invention.
[0021] Figure 5 FIG. 4 is a schematic diagram of a three-dimensional exploded view of a thin film circuit board according to an embodiment of the present invention.
[0022] Figure 6 FIG. 4 is a schematic diagram of a three-dimensional exploded view of a thin film circuit board according to an embodiment of the present invention.
[0023] The reference numerals are as follows:
[0024] 110: The First Film
[0025] 120: Second film
[0026] 130: Spacer layer
[0027] 130a: Opening
[0028] 140: First carbon ink contact
[0029] 140c: Connection pattern
[0030] 140m: Main pattern
[0031] 150: Corresponding contact
[0032] 151: Part 1
[0033] 152: Part 2
[0034] 160: First conductor
[0035] 170: Second wire
[0036] SR: Switch Region DETAILED DESCRIPTION
[0037] The advantages and features of the present invention and the methods for achieving the same will be more easily understood by describing them in more detail with reference to the exemplary embodiments and drawings. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, for those skilled in the art, the embodiments provided will make the present invention more thorough and comprehensive and fully convey the scope of the present invention.
[0038] The spatially relative terms used in this document, such as "lower" and "upper", are used to facilitate the description of the relative relationship between one element or feature and another element or feature in the drawings. The true meaning of these spatially relative terms includes other orientations. For example, when the drawings are flipped 180 degrees up and down, the relationship between one element and another element may change from "lower" to "upper". The spatially relative descriptions used in this document should also be interpreted in the same way.
[0039] As described in the prior art, existing keyboards may have ghost key phenomena. Although a diode can be set near each key contact to prevent the ghost key phenomenon from occurring, the cost of this approach is too high and the process is too complicated. Accordingly, the present invention provides a thin film circuit board for preventing ghost keys, by setting a high-resistance first carbon ink contact as a contact in a specific switch area. When this high-resistance contact contacts another contact, a matrix signal with a specific high impedance value is generated for the processor to identify, which can effectively prevent the ghost key phenomenon from occurring. Various embodiments of the thin film circuit board of the present invention will be described in detail below.
[0040] Figure 1 FIG. 1 is a three-dimensional exploded schematic diagram of a thin film circuit board according to an embodiment of the present invention. Figure 1 As shown, the thin film circuit board includes a first thin film 110 , a second thin film 120 , a spacer layer 130 , a first carbon ink contact 140 and a corresponding contact 150 . Figure 2 FIG. 1 is a schematic top view of a first film, a first carbon ink contact, and a first conductive line according to an embodiment of the present invention. Figure 2 As shown, the thin film circuit board has at least one switch region SR.
[0041] like Figure 1 As shown, the second film 120 is located above the first film 110. The spacer layer 130 is located between the first film 110 and the second film 120. The spacer layer 130 is located in the switch area (reference Figure 2 The switching region SR) has an opening 130a. Figure 1 The opening 130a is provided at a position corresponding to Figure 2 In other words, the opening 130a is used to define the position of the switch area SR of the thin film circuit board. In some embodiments, the first film 110, the second film 120 and the spacer layer 130 can be made of plastic materials, such as polycarbonate (PC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polyurethane (PU) or polyimide (PI). The film made of plastic material has the characteristics of insulation, heat resistance, bendability and high resilience, so that the manufactured thin film circuit board has flexibility, which is similar to the well-known flexible printed circuit (FPC).
[0042] like Figure 1 and Figure 2 As shown, the first carbon ink contact 140 is disposed on one of a portion of the upper surface of the first film 110 corresponding to the opening 130a and a portion of the lower surface of the second film 120 corresponding to the opening 130a. Figure 1 and Figure 2As shown, the first carbon ink contact 140 is disposed on the portion of the upper surface of the first film 110 corresponding to the opening 130a. The first carbon ink contact 140 does not have metal.
[0043] like Figure 1 As shown, the corresponding contact 150 corresponds to (or can be said to be substantially aligned with) the first carbon ink contact 140, and is disposed on the other of the portion of the corresponding opening 130a on the upper surface of the first film 110 and the portion of the corresponding opening 130a on the lower surface of the second film 120. In some embodiments, as Figure 1 As shown, the corresponding contact 150 is disposed on the portion of the corresponding opening 130a on the lower surface of the second film 120. The corresponding contact 150 is a second carbon ink contact or a conductive contact (whose resistance is lower than that of the first carbon ink contact 140).
[0044] In some embodiments, Figure 1 and Figure 2 As shown, the thin film circuit board further includes a first conductive wire 160 (eg, formed of silver paste) connected to the first carbon ink contact 140. In some embodiments, as Figure 1 As shown, the first carbon ink contact 140 includes a main pattern 140m and a connection pattern 140c connected to the main pattern 140m, and the connection pattern 140c is also connected to the first wire 160. The connection pattern 140c is configured to indicate the position where the first wire 160 is connected to it. In some embodiments, one end of the first wire 160 overlaps with the first carbon ink contact 140. In some embodiments, the first wire 160 does not surround the first carbon ink contact 140. In other embodiments, one end of the first wire may extend to the center of the switch area, and the first carbon ink contact is disposed above the end of the first wire (not shown).
[0045] In some embodiments, reference Figure 1 , the corresponding contact 150 is a second carbon ink contact. The second carbon ink contact does not have metal. The first carbon ink contact 140 and the second carbon ink contact can be formed of the same or different carbon ink materials. The first carbon ink contact 140 and / or the second carbon ink contact can be formed by a printing process. In some embodiments, the thin film circuit board also includes a second wire 170 (for example, formed of silver paste), which connects the second carbon ink contact. In some embodiments, the second wire 170 does not surround the second carbon ink contact.
[0046] Please refer to Figure 1When the user does not press the button, the first carbon ink contact 140 and the corresponding contact 150 are not in contact with each other; when the user presses the button, the second film 120 is squeezed and deformed (for example, protruding downward), so that the corresponding contact 150 contacts the first carbon ink contact 140, and the first wire 160 and the second wire 170 are connected through the first carbon ink contact 140 (with high impedance) and the corresponding contact 150, generating a matrix signal with a specific high impedance value for the processor (such as a microcontroller unit (MCU)) to identify.
[0047] In practical applications, the shape, area and thickness of the first carbon ink contact 140 can be appropriately designed according to the applicable recognition range of the impedance value of the matrix signal of the processor, so that the first carbon ink contact 140 and the corresponding contact 150 can generate a matrix signal with a specific high impedance value after contacting and conducting with each other, so that the processor can identify which specific key is pressed. Furthermore, since the two contacts can be designed as two carbon ink contacts (i.e., the first carbon ink contact 140 and the second carbon ink contact), or as one carbon ink contact (i.e., the first carbon ink contact 140) and one conductive contact, and different designs can be made for the shape, area and thickness of the carbon ink contacts, a contact combination that can generate a matrix signal with significantly different high impedance values can be quickly designed, so that the processor can more easily identify which specific key is pressed.
[0048] In some embodiments, the thin film circuit board has multiple switch areas (refer to Figure 2 , which shows one of the switch regions SR) and the surrounding area (or routing area, refer to Figure 2 , not shown) surrounds the plurality of switch regions, but no carbon ink material is disposed on another portion of the upper surface of the first film 110 in the peripheral region (eg Figure 2 Compared with setting the high impedance line segment above the peripheral area of a certain film to connect the contact point, the present invention sets the first carbon ink contact 140 directly on the switch area of the first film 110 or the switch area of the second film 120, without occupying the peripheral area, so it will not affect the peripheral circuit layout.
[0049] In addition, generally speaking, if a matrix signal having a specific high impedance value (e.g., 2,000 ohms to 5,000 ohms) is generated after two specific contacts are turned on, the circuit layout of the peripheral area will be appropriately changed and the circuit layout of the peripheral circuit will be affected. However, in one embodiment of the present invention, two carbon ink contacts (i.e., the first carbon ink contact 140 and the second carbon ink contact) are respectively arranged on the switch area of the first film 110 and the switch area of the second film 120, so that the two carbon ink contacts can generate a matrix signal having a specific high impedance value (e.g., 2,000 ohms to 5,000 ohms) after the two carbon ink contacts are turned on, without changing the circuit layout of the peripheral area, and will not affect the circuit layout of the peripheral circuit.
[0050] On the other hand, in terms of process, compared with printing high-impedance line segments with smaller line widths to connect wires / contacts, which are prone to tolerance, in the present invention, printing carbon ink contacts with larger areas to connect wires is less likely to produce tolerances. In addition, the thin film circuit board may also have a tail area (not shown), which is connected to a portion of one side of the peripheral area, and the portion of the side of the peripheral area is between the switch area and the tail area. In the tail area, multiple lines are arranged on the upper surface of the first film or the lower surface of the second film, and carbon ink patterns can be respectively provided above the ends of the multiple lines so that the multiple lines can be well electrically connected to a connector (not shown), and these carbon ink patterns can be formed in the same printing process as the first carbon ink contacts, without the need for an additional process to form the carbon ink patterns.
[0051] Other embodiments of the thin film circuit board of the present invention are provided below. Figure 3 FIG. 1 is a perspective exploded schematic diagram of a thin film circuit board according to an embodiment of the present invention. Figure 3 As shown, the first wire 160 surrounds at least a portion of the first carbon ink contact 140 , or even the entire first carbon ink contact 140 ; the second wire 170 surrounds at least a portion of the corresponding contact 150 (eg, the second carbon ink contact), or even the entire corresponding contact 150 .
[0052] Figure 4 FIG. 1 is a perspective exploded schematic diagram of a thin film circuit board according to an embodiment of the present invention. Figure 4 As shown, the corresponding contact 150 is a conductive contact (eg, formed by silver paste), which includes a first portion 151 and a second portion 152, and a gap is separated between the first portion 151 and the second portion 152. In some embodiments, the first portion 151 and the second portion 152 extend to the peripheral area respectively.
[0053] Figure 5FIG. 1 is a perspective exploded schematic diagram of a thin film circuit board according to an embodiment of the present invention. In some embodiments, the first carbon ink contact 140 includes a plurality of strip-shaped carbon ink contacts. In some embodiments, the first conductive wire 160 surrounds at least a portion of the first carbon ink contact 140 .
[0054] Figure 6 FIG. 1 is a perspective exploded schematic diagram of a thin film circuit board according to an embodiment of the present invention. Figure 6 As shown, the corresponding contact 150 is a conductive contact (eg, formed by silver paste), and a gap is provided between two ends of the conductive contact. In some embodiments, the corresponding contact 150 extends to the peripheral area.
[0055] However, the above is only a preferred embodiment of the present invention, and it cannot be used to limit the scope of the present invention. That is, all simple equivalent changes and modifications made according to the claims and the invention description of the present invention are still within the scope of the present invention. In addition, any embodiment or claim of the present invention does not need to achieve all the purposes, advantages or features disclosed in the present invention. In addition, the abstract part and the title are only used to assist the search of patent documents, and are not used to limit the scope of rights of the present invention.
Claims
1. A thin film circuit board having at least one switch area, the thin film circuit board comprising: a first film; a second film, located above the first film; a spacer layer, located between the first film and the second film, and having an opening in the at least one switch region; A first carbon ink contact point is disposed on one of a portion of an upper surface of the first film corresponding to the opening and a portion of a lower surface of the second film corresponding to the opening; as well as A corresponding contact corresponds to the first carbon ink contact and is arranged on the other of the portion of the upper surface of the first film corresponding to the opening and the portion of the lower surface of the second film corresponding to the opening, wherein the corresponding contact is a second carbon ink contact or a conductive contact, and a resistance of the conductive contact is less than a resistance of the first carbon ink contact.
2. A thin film circuit board as described in claim 1, wherein the thin film circuit board has a plurality of switch areas and a peripheral area surrounding the plurality of switch areas, and no carbon ink material is arranged on another part of the upper surface of the first film in the peripheral area and another part of the lower surface of the second film in the peripheral area.
3. The thin film circuit board according to claim 1, further comprising: A first conductive wire is connected to the first carbon ink contact. 4 . The thin film circuit board as claimed in claim 3 , wherein the first carbon ink contact comprises a main pattern and a connection pattern connected to the main pattern, and the connection pattern is also connected to the first conductive line. 5 . The thin film circuit board as claimed in claim 3 , wherein one end of the first conductive wire overlaps with the first carbon ink contact. 6 . The thin film circuit board as claimed in claim 3 , wherein the first conductive line does not surround the first carbon ink contact.
7. The thin film circuit board as claimed in claim 3, wherein the first conductive wire surrounds at least a portion of the first carbon ink contact.
8. The thin film circuit board as claimed in claim 3, wherein the corresponding contact is the second carbon ink contact, and the thin film circuit board further comprises: A second conductive wire is connected to the second carbon ink contact.
9. The thin film circuit board as claimed in claim 1, wherein the corresponding contact is the conductive contact, which includes a first portion and a second portion, and the first portion is separated from the second portion by a gap. 10 . The thin film circuit board as claimed in claim 1 , wherein the corresponding contact is the conductive contact, and two ends of the conductive contact are separated by a gap.