Keyboard backlight circuit, driving method, and key input apparatus

Abstract

A keyboard backlight circuit integrated with a key detection function, a keyboard backlight circuit driving method, and a key input apparatus. The keyboard backlight circuit comprises a plurality of scanning lines (10) and a plurality of output lines (11); each scanning line (10) has a main line (102) and a plurality of branch lines (103) connected in parallel with the main line (102), the main line (102) having first voltage terminals (100), and each branch line (103) having a second voltage terminal (101); a light-emitting diode (D1-D9) and a first resistor (R1-R9) connected in series are arranged in sequence between each second voltage terminal (101) and a connection position of each branch line (103) with the main line (102), the light-emitting diodes (D1-D9) causing a current to be unidirectionally conducted towards the first resistors (R1-R9); each output line (11) has a voltage output terminal (110), and a plurality of switch circuits (12) connected to the plurality of scan lines (10), respectively, the switch circuits (12) being connected to portions of the scan lines (10) located between the light-emitting diodes (D1-D9) and the first resistors (R1-R9), and each switch circuit (12) comprising a key switch (SW1-SW9). By means of arranging the switch circuits (12) in series in the keyboard backlight circuit, the functions of key detection and anti-ghosting can be implemented while achieving a keyboard backlight effect.

Description

A keyboard backlight circuit, driving method, and key input device.

[0001] Priority information: This application claims priority to Chinese patent applications filed on October 15, 2024, with application numbers 202411439919.0, 202411439918.6 and 202411439917.1, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to information input devices, and more particularly to a keyboard backlight circuit with integrated key detection function, a keyboard backlight circuit driving method, and a key input device. Background Technology

[0003] With the development of technology, electronic devices have become increasingly diverse. In order to achieve human-computer interaction, electronic devices are usually equipped with buttons. For example, computers are often equipped with keyboards for typing, gaming, and other operations.

[0004] To ensure usability in dark or dimly lit environments, some keyboards feature backlighting. This uses LEDs (light-emitting diodes) to illuminate the keys or surrounding areas, allowing users to identify the positions of each key and perform accurate keystrokes. The backlighting function is achieved through a backlight circuit, which contains LEDs corresponding to the key positions. The backlighting is controlled by illuminating these LEDs.

[0005] Furthermore, in order to receive information from key presses, the keyboard is also equipped with a key detection circuit, which identifies which key has been pressed.

[0006] In other words, keyboards with backlighting require both backlighting and key detection circuitry, resulting in complex circuitry, multiple circuit board layers, or even stacked circuit boards, leading to greater thickness and higher cost. Furthermore, keyboards with color backlighting require even more complex circuitry, further increasing thickness.

[0007] For some products that strive for thinness and lightness, complex circuit board designs will make the overall circuit board too thick, failing to meet the requirements of thin and light laptops.

[0008] The above content is only used to help understand the technical solution of this application and does not constitute an admission that the above is prior art.

[0009] Summary of the Invention

[0010] The purpose of this invention is to provide a keyboard backlight circuit, a keyboard backlight circuit driving method, and a key input device that integrate key detection function, which can realize keyboard backlight function and anti-ghost key detection function, and the circuit structure is simple.

[0011] To achieve the above-mentioned objectives, in a first aspect, the present invention proposes a keyboard backlight circuit with integrated key detection function, comprising:

[0012] Multiple scan lines are arranged at intervals. Each scan line has a main line and multiple parallel branch lines connected to the main line. The main line has a first voltage terminal, and each branch line has a second voltage terminal. A series-connected light-emitting diode (LED) and a first resistor are sequentially arranged between the connection point of the branch line and the main line and the second voltage terminal. The LED is used to realize keyboard backlighting and allows current to unidirectionally flow through the first resistor.

[0013] Multiple output lines are arranged at intervals and interspersed with the scan lines to form a matrix circuit. Each output line has a voltage output terminal and multiple switching circuits that are respectively connected to branches of the multiple scan lines. Each branch is provided with a corresponding switching circuit. The switching circuit is connected to the portion of the branch located between the light-emitting diode and the first resistor. The switching circuit includes a push-button switch.

[0014] Secondly, the present invention proposes a keyboard backlight circuit driving method, which is executed by a keyboard backlight circuit with integrated key detection function as described above. The keyboard backlight circuit driving method includes the following steps:

[0015] S1. A high level of a preset duration is sequentially applied to the first voltage terminal of a plurality of scan lines, and a high level is applied to the first voltage terminal of only one scan line at a time;

[0016] S2. During the period when the high level is applied, detect the voltage signal at the voltage output terminal of all the output lines and determine whether the voltage magnitude is within the preset amplitude range;

[0017] S3. When the magnitude of the voltage signal at a certain voltage output terminal is detected to be within the preset amplitude range, the triggered button switch is determined by combining the high-level scan line and the voltage conditions of the voltage output terminals of the multiple output lines.

[0018] Thirdly, the present invention proposes a key input device, including a keyboard backlight circuit with integrated key detection function as described above.

[0019] Furthermore, the key input device includes:

[0020] The first circuit board is provided with the aforementioned output line;

[0021] The second circuit board includes the scan lines, the light-emitting diodes, and the first resistor; and...

[0022] A push-button switch includes a first contact located on the first circuit board and electrically connected to the output line, and a second contact located on the second circuit board and electrically connected to the scan line, wherein the first contact and the second contact are arranged at a relative interval.

[0023] A reset element and a button are respectively arranged above the push-button switch. The light-emitting diode is located below the button and is exposed on the first circuit board to emit light toward the button. The first circuit board is closer to the button than the second circuit board.

[0024] Fourthly, the present invention proposes a keyboard backlight circuit driving method, wherein the keyboard backlight circuit driving method is executed by a keyboard backlight circuit with integrated key detection function. The keyboard backlight circuit with integrated key detection function includes multiple scan lines arranged at intervals and multiple output lines arranged at intervals. The multiple output lines and the multiple scan lines are arranged in an alternating matrix circuit. The scan lines are provided with light-emitting diodes for keyboard backlighting. The output lines have multiple switching circuits respectively connected to the multiple scan lines. The switching circuits include key switches.

[0025] The keyboard backlight circuit driving method includes the following steps:

[0026] A1. Drive the LED to emit light as needed during the first time period t10;

[0027] A2. During the second time period t11, perform button detection;

[0028] A3. Repeat steps A1 and A2 in sequence.

[0029] Fifthly, the present invention proposes a keyboard backlight circuit with integrated key detection function, comprising:

[0030] Multiple scan lines are arranged at intervals. Each scan line has a main line and multiple parallel branch lines connected to the main line. The main line has a first voltage terminal, and each branch line has a second voltage terminal. A light-emitting unit and a first resistor are sequentially arranged between the connection point of the branch line and the main line and the second voltage terminal. The light-emitting unit is used for keyboard backlighting and includes at least two light-emitting diodes emitting different colors of light. One of the light-emitting diodes is connected in series with the first resistor, allowing current to flow unidirectionally towards the first resistor.

[0031] Multiple output lines are arranged at intervals and interspersed with the scan lines to form a matrix circuit. Each output line has a voltage output terminal and multiple switch circuits that are respectively connected to branches of the multiple scan lines. Each branch is provided with a corresponding switch circuit. The switch circuit and the portion of the branch connected to it located between the light-emitting diode and the first resistor are connected. The switch circuit includes a push-button switch.

[0032] Sixthly, the present invention proposes a keyboard backlight circuit driving method, characterized in that it is executed by a keyboard backlight circuit with integrated key detection function as described above, and includes the following steps:

[0033] A1. Drive the LED to emit light as needed during the first time period t10;

[0034] A2. During the second time period t11, perform button detection;

[0035] A3. Repeat steps A1 and A2 in sequence.

[0036] Compared with existing technologies, the present invention has the following advantages: According to some embodiments of the present invention, the keyboard backlight circuit integrating key detection function, by inserting a switching circuit in series in the keyboard backlight circuit, can achieve key detection and anti-ghosting functions while providing the keyboard backlight effect, thereby simplifying the circuit structure and reducing costs. At the same time, the simplified circuit structure can reduce the number of circuit board layers in the key output device, thereby helping to reduce the thickness of the key input device and achieve a thinner and lighter electronic device.

[0037] In addition, according to some embodiments of the present invention, the light-emitting diode is driven to emit light on demand during the first time period t10; and key detection is performed during the second time period t11. This can generate diverse lighting effects during the first time period t10, increasing aesthetics, while key detection during the second time period t11 does not affect the normal recognition of the key. Attached Figure Description

[0038] Figure 1 is a circuit diagram of a keyboard backlight circuit with integrated key detection function according to an embodiment of the present invention.

[0039] Figure 2 is a schematic diagram of the circuit shown in Figure 1 to prevent false detection.

[0040] Figure 3 is a circuit diagram of a keyboard backlight circuit with integrated key detection function according to an embodiment of the present invention. In the figure, the switching circuit is provided with a second resistor.

[0041] Figure 4 is a timing diagram of applying a high level to each scan line during key detection according to an embodiment of the present invention. The figure shows two scan cycles.

[0042] Figure 5 is a timing diagram of one emission cycle according to an embodiment of the present invention.

[0043] Figure 6 is a timing diagram of one emission cycle according to an embodiment of the present invention.

[0044] Figure 7 is a timing diagram of one emission cycle of an embodiment of the present invention.

[0045] Figure 8 is a timing diagram of the energizing cycle of each scan line in one embodiment of the present invention.

[0046] Figure 9 is a timing diagram of the energizing cycles of each scan line in one embodiment of the present invention.

[0047] Figure 10 is a circuit diagram of a control circuit according to an embodiment of the present invention.

[0048] Figure 11 is a schematic diagram of the key input device according to an embodiment of the present invention.

[0049] Figure 12 is a schematic diagram of the key input device according to an embodiment of the present invention. Detailed Implementation

[0050] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0051] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0052] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0053] This invention proposes a keyboard backlight circuit (hereinafter referred to as the keyboard backlight circuit) with integrated key detection function, which can be used in keyboards or electronic devices with multiple keys. The keyboard backlight circuit can realize the backlight of the keyboard and also detect the keys to determine which key of the device is pressed.

[0054] As shown in Figure 1, the keyboard backlight circuit according to one embodiment of the present invention includes multiple scan lines 10 and multiple output lines 11. The multiple scan lines 10 are arranged at intervals, and the multiple output lines 11 are also arranged at intervals, forming a matrix circuit by alternating the scan lines 10 and output lines 11. As shown in Figure 1, there are three scan lines 10 and three output lines 11. For ease of description, the three scan lines 10 from top to bottom are referred to as the first scan line 10a, the second scan line 10b, and the third scan line 10c, respectively, and the three output lines 11 from left to right are referred to as the first output line 11a, the second output line 11b, and the third output line 11c, respectively.

[0055] It should be noted that in this document, the terms "multiple," "more than," or similar expressions indicate a quantity of at least two; that is, "more" means two or more. Therefore, in other embodiments, the number of scan lines 10 and output lines 11 can be two or more than three. Furthermore, although the number of scan lines 10 and output lines 11 is the same in the illustrated embodiment, this is not mandatory. The number of scan lines 10 and output lines 11 can differ; for example, one may have two lines, and the other three, etc.

[0056] The scan line 10 has a first voltage terminal 100 and a second voltage terminal 101. There can be multiple second voltage terminals 101. For example, in the embodiment shown in Figure 1, the scan line 10 includes a main line 102 and multiple branch lines 103 connected to the main line 102. The multiple branch lines 103 are arranged in parallel, and each branch line 103 has a second voltage terminal 101. A light-emitting diode (LED) and a first resistor are sequentially arranged between the connection point of the branch line 103 and the main line 102 and the second voltage terminal 101. The LED and the first resistor are connected in series. D1 to D9 in Figure 1 represent the LEDs, and R1 to R9 represent the first resistors. The LED allows current to flow unidirectionally towards the second voltage terminal 101. That is, the current flowing through the first voltage terminal 100 flows into the positive terminal of the LED, then flows out from the negative terminal of the LED, and flows through the first resistor, causing the LED to emit light. It is understood that due to the unidirectional conduction characteristic of the LED, current cannot flow from its negative terminal to its positive terminal.

[0057] Output line 11 has a voltage output terminal 110 and multiple switch circuits 12 connected to multiple scan lines 10 respectively. Specifically, the multiple switch circuits 12 are connected to branches 103 of multiple scan lines 10 respectively. More specifically, the switch circuits 12 and the portion of the branch 103 located between the light-emitting diode and the first resistor are connected. Multiple switch circuits 12 of the same output line 11 are connected in parallel. Each branch 103 is provided with a corresponding switch circuit 12. The switch circuit 12 includes a push-button switch, SW1 to SW9 marked in Figure 1, which are push-button switches. The push-button switches correspond to the positions of the buttons (usually located below the buttons). When the button is pressed, the button moves down, thereby triggering the push-button switch to close and turn on the switch circuit 12. Conversely, when the push-button switch is released, the button resets, causing the push-button switch to open.

[0058] The first voltage terminal 100 of the scan line 10 is used to input a driving voltage signal. When a high-level driving voltage is applied to the first voltage terminal 100 of the scan line 100, the light-emitting diode (LED) is driven to emit light. The LED can illuminate the keys, thus serving as keyboard backlight. Optionally, the LED is arranged adjacent to and corresponding to the key switch, for example, it can be located below the key. In some embodiments, the key is at least partially transparent, for example, the part displaying the letters can be made transparent, so that the LED can illuminate the corresponding letters. In some embodiments, the key can be completely transparent to present a crystal-clear feel and improve aesthetics. In some embodiments, the key is opaque, and its inner wall is provided with a reflective surface (e.g., coated with a reflective coating) to reflect the light from the LED, so that the area below the key is illuminated, creating a sense of light around the key.

[0059] Understandably, when a push-button switch (e.g., SW1) is pressed, and a high-level driving voltage is applied to the first voltage terminal 100 of the scan line 10 (e.g., the first scan line 10a) connected to it, the voltage output terminal 110 of the output line 11 (e.g., the first output line 11a) connected to the push-button switch will detect a voltage signal, which will also be high-level. Obviously, due to the voltage division effect of the light-emitting diode and the first resistor, the voltage at the voltage output terminal 110 will be less than the voltage at the first voltage terminal 100. However, compared to the case where the push-button switch is open, it is still high-level, only smaller than the high level of the first voltage terminal 100. Therefore, when a voltage signal of a magnitude within a preset range is detected at the voltage output terminal 110 of the output line 11, it indicates that a push-button switch has been pressed.

[0060] In theory, as long as the button switch is not pressed, the voltage signal at the voltage output terminal 110 will always be 0. Therefore, in some embodiments, the preset range can be greater than 0V, that is, as long as a certain voltage is detected, it is considered that the button has been pressed.

[0061] In some embodiments, to reduce interference from the external environment and improve detection accuracy, the preset range can be a range greater than 0V. It is understood that the voltage at the voltage output terminal 110 after the button is pressed can be calculated using the forward voltage value of the LED, the input voltage at the first voltage terminal 110 of the scan line, and the line resistance, or it can be obtained through actual measurement. In practice, even if the detected voltage value is less than the calculated or measured voltage value, as long as it is within the allowable amplitude range, the button can be considered pressed to ensure the sensitivity of the detection result. This allowable amplitude range can be used as the preset range for judging the magnitude of the voltage signal. The voltage value obtained through calculation or measurement can be used as the basis for judging whether there is a voltage at the voltage output terminal 110 within the preset range. When the voltage output terminal 110 detects a voltage signal with a magnitude within the preset amplitude range, it indicates that a button has been pressed. Optionally, when a voltage signal with a magnitude greater than or equal to a fixed value is detected, it indicates that a button switch has been pressed. That is, the preset range is a voltage signal greater than or equal to a fixed value. This voltage signal can be less than a calculated or measured voltage value of a certain amplitude, or it can be equal to a calculated or measured voltage value.

[0062] During key detection, a high-level driving voltage is sequentially applied to the first voltage terminal 100 of each scan line 10. During the period when the high level is applied, the voltage output terminal 110 of each output line 11 is detected. When a voltage output terminal 110 detects a voltage within a preset amplitude range, it indicates that the key switch connected between the output line 11 and the scan line 10 with the high level applied has been pressed (i.e. triggered). Thus, the position information of the pressed key can be obtained, thereby realizing key detection.

[0063] For example, when a high level is applied to the first scan line 10a, if a certain voltage is detected at the voltage output terminal 110 of the first output line 11a, it indicates that the push button switch SW1 is pressed. If a certain voltage is detected at the voltage output terminal 110 of the second output line 11b, it indicates that the push button switch SW2 is pressed. If a certain voltage is detected at the voltage output terminals 110 of both the first output line 11a and the second output line 11b, it indicates that the push button switches SW1 and SW2 are pressed simultaneously. This process continues, and by combining the high-level scan line 10 with the voltage conditions at the voltage output terminals 110 of the multiple output lines 11, the pressed button position can be determined, thus achieving button detection.

[0064] Because a light-emitting diode (LED) is connected in series in scan line 10, the unidirectional conduction characteristic of the LED can be used to achieve the effect of preventing ghost keys. For example, when current (i.e., a high-level driving voltage) is applied to the second scan line 10b, and key switches SW1, SW2, and SW4 are pressed simultaneously, only the voltage output terminal of the first output line 11a can detect a voltage within the preset amplitude range. Due to the unidirectional conduction of LED D1, current cannot flow into the second output line 11b from the dashed line shown in Figure 2, causing the voltage output terminal 110 of the second output line 11b to detect a high level. It can be understood that when no LED is set, current can flow along the dashed line shown in Figure 2, causing both the first output line 11a and the second output line 11b to output a high level. In this case, the key switch SW5, which is not pressed, may be mistakenly judged as pressed. Therefore, the above-mentioned keyboard backlight circuit can play a role in preventing false detection.

[0065] Understandably, the circuit structure design described above achieves both the backlighting effect of the buttons and the anti-ghosting function, thus simplifying the circuit structure and reducing costs. Furthermore, the simplified circuit structure reduces the number of circuit board layers in the button output device, thereby helping to reduce the thickness of the button input device and achieve a thinner and lighter electronic device.

[0066] The keyboard backlight circuit includes a chip. The first voltage terminal 100 and the voltage output terminal 110 are both connected to the chip's IO interface. The chip can input drive voltage signals to multiple scan lines according to the control signal and detect the voltage signal of the voltage output terminal 110 of the output line 11, thereby realizing backlight and key detection.

[0067] Optionally, the second voltage terminal 101 is a ground voltage terminal.

[0068] In some embodiments, the resistance of the first resistor is 100–1000 ohms, and the driving voltage of the input first voltage terminal 100 is approximately 5V. Setting the resistance of the first resistor to 100–1000 ohms allows the current flowing through the LED to be 1–10mA, which meets the current requirements for most LEDs used in keyboards. In other embodiments, the driving voltage of the input first voltage terminal 100 is approximately 3.3V. In this case, the resistance of the first resistor can be selected as 30–500 ohms to ensure reliable LED illumination.

[0069] The resistance value of the first resistor can be adjusted according to the actual current and voltage parameters required for the LED to operate normally, so that the LED can emit light reliably.

[0070] In some embodiments, as shown in FIG3, the switching circuit 12 further includes a second resistor connected in series with the push-button switch. R10 to R18, as indicated in FIG3, are the second resistors. The resistance value of the second resistor is greater than 0.2 times that of the first resistor, that is, the ratio of the resistance value of the second resistor to the resistance value of the first resistor is greater than 0.2, so as to ensure the reliability of the light-emitting diode's light emission during the button press process. It can be understood that in the embodiment shown in FIG1, when two or more push-button switches on the same output line 11 are pressed simultaneously, the first resistor corresponding to the pressed push-button switch will be connected in parallel. The resistance value after parallel connection is smaller than the resistance value of the individual first resistor, so that the resistance for voltage division with the light-emitting diode is smaller, and the current and voltage acting on the light-emitting diode will be larger. For example, referring to Figure 1, when a high level is input to the first voltage terminal 100 of the first scan line 10a, and SW1 and SW4 are pressed simultaneously, the resistance of the two first resistors connected in parallel will be only half of the original value, even if the resistance values ​​of the first resistors R1 and R4 are the same. Therefore, the current flowing through the light-emitting diode will increase, and the voltage acting on the light-emitting diode will also increase. The more buttons are pressed at the same time, the smaller the resistance value of the resistor that divides the voltage with the light-emitting diode will be. In this way, the light-emitting diode may be burned out due to excessive current flowing through it, or the brightness may be too high, shortening its service life.

[0071] This problem can be solved by setting a second resistor in series with the push-button switch in the switching circuit 12. In the embodiment shown in Figure 3, when multiple buttons on the same output line 10 are pressed simultaneously, the presence of the second resistor will result in a smaller decrease in the resistance of the resistor that ultimately divides the voltage with the LED. This ensures the stability of the current flowing through the LED when the button is pressed, reduces the current increase, and is beneficial for reliable LED illumination, resulting in a more consistent and stable illumination effect. It also helps to extend the LED's lifespan. For example, when the first voltage terminal 100 of the first scan line 10a is input with a high level, and push-button switches SW1 and SW4 are pressed simultaneously, the first resistor R1 is connected in parallel with resistors R10, R13, and R4. Since the resistance values ​​of resistors R10 and R13 are greater than 0.2 times the resistance values ​​of resistors R1 and R4, the resistance value after parallel connection will be greater than the resistance value after R1 and R4 are connected in parallel alone, reducing the current increase flowing through the LED.

[0072] To further ensure the stability of LED light emission, the resistance of the second resistor can be greater than or equal to 1, 2, 3, 4, 5, or more times the resistance of the first resistor. Optionally, the resistance of the second resistor is greater than or equal to twice the resistance of the first resistor, so that when the switch is pressed, the total current impact is less than 33%, the change in current flowing through the LED is smaller, and it will not cause significant optical and electrical effects on the LED, thereby effectively ensuring the stability of LED light emission and the reliability of its use.

[0073] Optionally, the resistance value of the second resistor shall not exceed 10 times the resistance value of the first resistor, because the detection input of the output line is generally in a high-impedance state. When the resistance at the detection end is too large, it will affect the accuracy of the detection value. Setting the resistance value of the second resistor to be less than 10 times the resistance value of the first resistor is beneficial to improving the accuracy of the detection value.

[0074] Optionally, the first and second resistors can be ordinary resistors, carbon ink resistors, silver paste printed resistors, or other resistors that can be used in thin film circuits.

[0075] The color of light emitted by LEDs is not limited; for example, it can be white, red, blue, or green. Optionally, all LEDs can emit light of the same color, or at least two LEDs can emit light of different colors to produce a richer lighting effect. The color of LEDs in different positions can be set as needed.

[0076] The following section introduces a method for driving the backlight using the keyboard backlight circuit described above.

[0077] The keyboard backlight circuit driving method includes the following steps:

[0078] S1. A high level of a preset duration is sequentially applied to the first voltage terminal 100 of multiple scan lines 10, and a high level is applied to the first voltage terminal 100 of only one scan line 10 at the same time, that is, a high level is applied to at most one scan line 10 at the same time.

[0079] S2. During the period when the high level is applied, detect the voltage signal at the voltage output terminal 110 of multiple output lines 11, and determine whether there is a voltage signal whose voltage magnitude is within the preset amplitude range, that is, determine whether the voltage magnitude of the detected voltage signal is within the preset amplitude range.

[0080] S3. When the magnitude of the voltage signal at a certain voltage output terminal 110 is detected to be within the preset amplitude range, the triggered button switch is determined by combining the voltage conditions of the high-level scan line 10 and the voltage output terminals 110 of multiple output lines 11.

[0081] It should be noted that in step S1, the high-level signal applied to the first voltage terminal 100 of multiple scan lines 10 for a preset duration does not necessarily have to be applied in the same order. For example, referring to Figure 4, the total time from applying a high-level signal to the first scan line 10 to the last scan line 10 is one scan cycle T1. Therefore, it is sufficient to apply a high-level signal to all scan lines 10 within one scan cycle T1; a specific order is not required. For example, in the first scan cycle T1, the first scan line 10a, the second scan line 10b, and the third scan line 10c can be applied in sequence, and in the second scan cycle, the first scan line 10a, the third scan line 10c, and the second scan line 10b can be applied in sequence. Of course, to simplify the procedure, optionally, each scan cycle T1 can always apply a high-level signal to each scan line in the same order, as shown in Figure 4, where the first scan line 10a, the second scan line 10b, and the third scan line 10c are applied in sequence.

[0082] In step S2, during the time period when each scan line 10 is connected to a high level, the voltage output terminal 110 of all output lines 11 is detected to ensure that no button is missed during detection.

[0083] Understandably, the scan period T1 is short enough that all scan lines 10 can be supplied with a high level at least once within the extremely short scan period, and the output voltage of all output lines 11 is detected when any scan line 10 is supplied with a high level, so that under normal operation, the button can be detected as pressed no matter when the hand presses the button.

[0084] Furthermore, to ensure continuous illumination of the LEDs, the scan period T1 is set to a time when flickering of the LEDs is imperceptible to the naked eye. Understandably, when a high level is input to a certain scan line 10, the LED on that scan line 10 will illuminate, while other LEDs will not. Therefore, the LEDs do not illuminate continuously but intermittently. When the interval is short enough, the flickering of the LEDs will be imperceptible to the naked eye, thus ensuring that the LEDs appear to be constantly lit.

[0085] Optionally, the interval between the light emission of the same LED is no more than 41.6ms, so that the human eye perceives it as constantly lit and cannot detect flickering.

[0086] Optionally, the scanning period T1 is no more than 41.6ms, which helps the LED to emit continuous light and ensures that the button can be detected as pressed under normal operation, regardless of when the hand presses the button.

[0087] To ensure sufficient time for detecting the voltage of the output line 11 after the scan line 10 is energized, in step S1, the duration of each high-level input on any scan line 10 is no less than 50 microseconds, allowing ample time for detecting the output line 11. Optionally, the duration of each high-level input on any scan line 10 is no less than 100 microseconds. As a further improvement, in step S2, the voltage output terminal 110 of the output line 11 is detected only after a preset time period following the high-level input on the scan line 10. Generally, the voltage level fluctuates (lasting approximately 10-30 microseconds) initially after the high-level input on the scan line 10. Therefore, performing voltage detection only after a preset time period following the high-level input on the scan line 10 allows for a more stable voltage at the output terminal 110, resulting in more accurate detection results. Optionally, the preset time period is greater than or equal to 30 microseconds, and more preferably greater than or equal to 50 microseconds, to ensure the accuracy of the detection results and avoid false detections caused by level fluctuations.

[0088] Optionally, step S3 includes the following steps:

[0089] S31. When the magnitude of the voltage signal at the voltage output terminal 110 of a certain output line 11 is detected to be within a preset amplitude range, a scan line 10 that is simultaneously supplied with a high level is acquired. For ease of description, the output line 11 corresponding to the voltage output terminal 110 whose detected voltage signal is within the preset amplitude range is referred to as the required output line 11.

[0090] S32. Identify the push-button switch connected between the detected qualified output line 11 and the scan line 10 that is simultaneously turned on with a high level, which is the push-button switch that has been triggered.

[0091] It is understandable that the position information of each button switch corresponding to the scan line 10 and the output line 11 has been recorded and stored in advance. Therefore, when the output line 11 with the detected voltage and the scan line 10 with the high level applied at the same time are known, the position information of the button switch can be obtained, thereby identifying which button switch is triggered. The position information of the button switch corresponds to the position of the button that was pressed.

[0092] Understandably, although the intermittent emission time of an LED is short enough and the frequency is fast enough to appear as continuous emission, the actual emission time of the LED is short over a period of time. For example, in the case of three scan lines 10, the LED emits light for only one-third of the time. This will result in the actual observed light brightness being lower than the light brightness observed when the LED is continuously powered on.

[0093] To address the aforementioned issue of low brightness, we will now introduce another keyboard backlight circuit driving method. For ease of description, the keyboard backlight circuit driving method described above will be referred to as the first keyboard backlight circuit driving method, and the one described below will be referred to as the second keyboard backlight circuit driving method.

[0094] Referring to Figure 5, the second method for driving the keyboard backlight circuit includes the following steps:

[0095] A1. Drive the LED to emit light as needed during the first time period t10.

[0096] A2. During the second time period t11, key press detection is performed.

[0097] A3. Repeat steps A1 and A2 in sequence.

[0098] In the second keyboard backlight circuit driving method, all LEDs first emit light on demand during the first time period t10, such as remaining constantly lit, or creating breathing or flashing lighting effects. Then, key detection is performed during the second time period t11, increasing the number of lighting modes. Simultaneously, while the LEDs continuously emit light during the first preset time period, within the same time frame (longer than the sum of the first and second time periods t10 and t11), the LED's on-time in the second keyboard backlight circuit driving method is longer than that in the first method. This results in higher perceived brightness, further improving display quality and aesthetics. When LEDs are used to illuminate letters on keys, they are more easily identified.

[0099] During the first time period t10, a driving voltage signal can be input to the first voltage terminal 100 of all scan lines 10 according to the control signal to drive all light-emitting diodes (LEDs) to emit light according to the control signal, such as continuously emitting light or producing a lighting effect. In some embodiments, during the first time period t10, a high level is continuously input to the first voltage terminal 100 of all scan lines 10. In this embodiment, the LEDs emit light continuously during the first preset time period t10 to maximize the brightness of light emitted by the naked eye. In other embodiments, during the first time period t10, a high level is input to the first voltage terminal 100 of all scan lines 10 according to the control signal. The timing and sequence of the high level input can be set as needed, so that each LED emits light as needed, such as emitting light sequentially or at intervals, to produce diverse lighting effects. The LEDs can be controlled to emit light as needed, for example, by using PWM to control the LEDs to produce flashing or flowing light effects.

[0100] The first time period t10 and the second time period t11 constitute a light-emitting cycle. It can be understood that the longer the first time period t10, the longer the LED can continuously emit light during that period, resulting in a brighter perceived brightness. When the LED produces a lighting effect during this period, it reduces the visual perception of the light emitted during the second time period t11, better ensuring the continuity of the lighting effect. Optionally, the first time period t10 can be longer than the second time period t11, allowing the LED to emit light with good brightness and improving the continuity of the lighting effect. Further, the first time period t10 and the light-emitting cycle T2 should account for at least 80% of the total time. This ensures that the brightness perceived by the naked eye is approximately consistent with the brightness achieved by the LED when it is continuously powered, further improving the continuity of the lighting effect. The ratio of the first time period t10 to the light-emitting cycle T2 can be further selected to be at least 90%. Even further, the ratio of the first time period t10 to the light-emitting cycle T2 should not exceed 99.9% to prevent inaccurate button detection due to an excessively short detection time.

[0101] Understandably, the light emission period T2 needs to be short enough that all scan lines 10 can be switched on at least once within the extremely short light emission period T2, and the output voltage of all output lines 11 is detected when any scan line 10 is switched on, so that under normal operation, the button can be detected as pressed no matter when the hand presses the button.

[0102] Optionally, the duration of the light emission period T2 is no greater than (or less than or equal to, not exceeding) 41.6 ms, which helps the light-emitting diode to emit continuous light in a sensory sense, and ensures that under normal operation, the button can be detected as pressed regardless of when the hand presses the button.

[0103] Key detection can be achieved in various ways. This manual illustrates two methods. The first key detection step in step A2 includes:

[0104] A21. A high level of a preset duration is sequentially applied to the first voltage terminal 100 of multiple scan lines 10, and at the same time, only the first voltage terminal 100 of one scan line 10 is applied to the high level, that is, at most one scan line 10 is applied to the high level at the same time.

[0105] A22. During the period when the high level is applied, detect the voltage signal at the voltage output terminal 110 of multiple output lines 11, and determine whether there is a voltage signal whose voltage magnitude is within the preset amplitude range.

[0106] A23. When the magnitude of the voltage signal detected at a certain voltage output terminal 110 is within the preset amplitude range, the triggered button switch is determined by combining the voltage conditions of the high-level scan line 10 and the voltage output terminals 110 of multiple output lines 11.

[0107] It is understandable that the key detection step in step A2 is basically the same as the step in the first keyboard backlight circuit driving method. You can refer to the relevant content in the first keyboard backlight circuit driving method above.

[0108] The total time from applying a high-level signal to the first scan line 10 to the last scan line 10 is one scan cycle T3. It is understood that in the second keyboard backlight circuit driving method, the second time period t11 and the scan cycle T3 have the same length. Of course, they can also be different. For example, referring to Figure 6, there can be an interval before and / or after the scan cycle T3 so that the second time period t11 is longer than the scan cycle T3. Furthermore, the second time period t11 is not limited to including only one scan cycle T3; it can include more scan cycles for more thorough detection and improved detection accuracy. Clearly, setting the second time period t11 and the time interval of N scan cycles T3 (N is an integer greater than or equal to 1) to have the same length allows for more efficient use of time and improved work efficiency.

[0109] Similarly, the scan period T3 can be no more than 41.6ms.

[0110] Similarly, in step A21, the duration of each high-level input on any of the scan lines 10 is no less than 50 microseconds, and more preferably no less than 100 microseconds. In step A22, the voltage output terminal 110 of the output line 11 is detected only after a preset time period following the high-level input to the scan line 10, to ensure a more stable voltage at the voltage output terminal 110 and more accurate detection results. Optionally, the length of the preset time period is greater than or equal to 30 microseconds, and more preferably greater than or equal to 50 microseconds, to ensure the accuracy of the detection results and avoid false detections caused by level jitter.

[0111] Similarly, step A23 may include the following steps:

[0112] A231. When the magnitude of the voltage signal at the voltage output terminal 110 of a certain output line 11 is within a preset amplitude range, the scan line 10 that is simultaneously supplied with a high level is acquired.

[0113] A232. Identify the push-button switch connected between the detected qualified output line 11 and the scan line 10 that is simultaneously supplied with a high level. This push-button switch is the triggered push-button switch. The qualified output line 11 refers to the output line 11 corresponding to the voltage output terminal 110 where the magnitude of the detected voltage signal is within the preset amplitude range.

[0114] Optionally, in order to make the human eye recognize the constantly lit light, the duration of the second time period t11 is less than or equal to 41.6ms, so that the human eye cannot recognize the flickering of the light-emitting diode during button detection.

[0115] Optionally, the duration of the light emission period T2 is not greater than (or less than or equal to, not exceeding) 41.6 ms, so that the duration of the light emission period T2 is short enough to reliably identify normal button operation by human hand. Optionally, the duration of the second time period t11 is less than or equal to 15 ms, so as to further improve the continuity of the light emission of the LED recognized by the human eye, and make the human eye observe the LED as basically always lit.

[0116] Referring to Figure 7, the second button detection step in step A2 includes:

[0117] A21'. During the second time period t11, drive voltage signals are applied to the first voltage terminals 100 of all scan lines 10 in a preset manner. The frequency components of the drive voltage signals applied to different scan lines 10 are different, and the voltage signals of the voltage output terminals 110 of all output lines 11 are continuously received.

[0118] A22'. Sample the voltage signal received from the voltage output terminal 110 to obtain the frequency component information of the voltage signal from different voltage output terminals 110;

[0119] A23'. Determine the triggered push-button switch based on the frequency component information of the voltage signal.

[0120] The driving voltage signal can be, for example, a sine wave signal, a square wave signal, or other quadrature signals with a certain frequency. Since the voltage output terminal 110 of the output line 11 can only detect the voltage of the corresponding frequency component when the key switch on the output line 11 is pressed, the frequency component of the voltage signal at the voltage output terminal 110 can be used to determine which key is pressed. Furthermore, since the triggered key switch is determined by detecting the frequency component of the voltage signal, multiple (at least two or even all) scan lines 10 can be simultaneously supplied with driving voltage signals, without the need for sequential supply. When the same output line 11 detects voltage signals containing multiple different frequency components, it indicates that multiple key switches connected to different scan lines 10 have been pressed.

[0121] Specifically, step A23' may include the following steps:

[0122] A231'. Identify the scan line 10 of the driving voltage signal with the corresponding frequency component based on the frequency component information of the voltage signal at the voltage output terminal 110 of the output line 11;

[0123] A232'. Identify the push-button switch connected between the output line 11 and the scan line 10, which have the same voltage frequency components; this push-button switch is the one that has been triggered.

[0124] It is understandable that the position information of each button switch corresponding to the scan line 10 and the output line 11 has been recorded and stored in advance. Therefore, when the scan line 10 and the output line 11 with the same voltage frequency components are known, the position information of the button switch can be obtained, thereby identifying the triggered button switch. The position information of the button switch corresponds to the position of the button.

[0125] For example, referring to Figure 1 or Figure 3, drive voltage signals containing frequency components of 1kHz, 2kHz, and 3kHz are respectively applied to the first scan line 10a, the second scan line 10b, and the third scan line 10c. When the voltage output terminal 110 of the first output line 11a detects a voltage signal containing a 1kHz frequency component, the push-button switch SW1 connected to the first output line 11a and the first scan line 10a can be located (indicating that the push-button switch SW1 is pressed), and the position information corresponding to the push-button switch can be obtained to determine the pressed button. When the voltage output terminal 110 of the first output line 11a detects voltage signals containing frequency components of 1kHz, 2kHz, and 3kHz, the push-button switches connected between the first output line 11a and the first scan line 10a, the second scan line 10b, and the third scan line 10c can be identified as SW1, SW4, and SW7, indicating that the push-button switches SW1, SW4, and SW7 are all pressed. The position information corresponding to the push-button switches SW1, SW4, and SW7 can be obtained to determine the pressed button. The button conditions for other output lines 11 can be deduced similarly. For example, when drive voltage signals containing 1KHz, 2KHz, and 3KHz frequency components are applied to the first scan line 10a, the second scan line 10b, and the third scan line 10c, respectively, if the voltage output terminal 110 of the first output line 11a detects a voltage signal containing a 1KHz frequency component, it indicates that the button switch SW1 is pressed. If the voltage output terminal 110 of the first output line 11a detects voltage signals containing 1KHz, 2KHz, and 3KHz frequency components, it indicates that the button switches SW1, SW4, and SW7 are all pressed. The button conditions for other output lines 11 can be deduced similarly.

[0126] Optionally, in step A21', the difference in the center frequency of the driving voltage signal supplied to the first voltage terminal 100 of each scan line 10 is not less than one percent of the highest sampling rate of the output line, so that the frequency components of the voltage signal have a large difference, which facilitates accurate identification of the frequency component information of the voltage output terminal 110.

[0127] Optionally, in step A22', the frequency component information of the voltage signal at different voltage output terminals 110 is obtained by performing Fourier expansion on the sampled voltage signal.

[0128] Understandably, since multiple scan lines 10 can be driven with voltage signals simultaneously and the output line 11 can be continuously sampled and detected, there is no need to sequentially apply driving voltage signals to the scan lines 10. Therefore, compared to sequentially applying high-level signals to the scan lines 10 for detection, the time for applying driving voltage signals to each scan line 10 can be increased, thus effectively ensuring the detection time and improving detection accuracy. Furthermore, the frequency of the voltage is less susceptible to external environmental influences (such as static electricity) than the voltage magnitude, further enhancing detection accuracy.

[0129] It is understandable that applying a driving voltage signal to the first voltage terminal 100 of the scan line 10 in a preset manner can include various methods.

[0130] In some embodiments, the preset method is to continuously supply a driving voltage signal to the first voltage terminal 100 of all scan lines 10. In this embodiment, since the driving voltage signal can be continuously supplied and the output line 11 is continuously detected, the accuracy of key detection can be greatly improved, timeliness can be guaranteed, delay can be reduced, and the situation where no key operation is detected due to the time interval of the driving voltage signal supply will not occur, making it more reliable. Furthermore, each scan line 10 has a continuous voltage input during key detection, so each light-emitting diode can still emit light continuously during the second time period t11. When the continuous emission of light-emitting diodes is required, the continuity and brightness of the observed light can be increased.

[0131] In other embodiments, the preset method is to apply a high-level driving voltage to the scan line 10 according to a preset power-on cycle for each scan line. The power-on cycle of each scan line 10 may be the same or different. The power-on cycle includes power-on time and non-power-on time. It is understood that the voltage signal applied within the power-on cycle is a driving voltage signal with a certain frequency component. The power-on time included in the power-on cycle corresponding to each scan line 10 may be the same or different. Referring to Figures 8 and 9, the power-on cycles of the first scan line 10a, the second scan line 10b, and the third scan line 10c are T3, T4, and T5, respectively. In the embodiment shown in Figure 8, the durations of the power-on cycles T3, T4, and T5 are different, and the power-on time t_on and the non-power-on time t_off each account for half of the power-on cycle of each scan line 10. In the embodiment shown in Figure 9, the durations of the power-on cycles T3, T4, and T5 are the same, and the power-on time ton within the power-on cycle of each scan line 10 is much longer than the non-power-on time toff. This allows for a longer power-on time for the scan lines 10, which is more conducive to improving the accuracy of button detection and reducing the delay in button detection. Further optionally, when the driving voltage is applied to the scan line 10 according to the preset power-on cycle of each scan line, all scan lines 10 or at least two scan lines 10 are simultaneously supplied with driving voltage signals within a certain time period.

[0132] Optionally, within one power-on cycle, the power-on time is greater than 1 / M of the power-on cycle, where M is the total number of scan lines 10 in the keyboard backlight circuit. This can improve the power-on time, ensuring detection accuracy, and also increase the light-emitting time of the LEDs, increasing the perceived brightness. Further, optionally, within one power-on cycle, the power-on time is greater than half of the power-on cycle to further improve the effect.

[0133] Understandably, keyboards use backlighting units to illuminate the keys. These units are located below the keys and emit light towards the side where the key is located. Generally, each key has its own backlighting unit. The backlight color can be monochrome or multi-colored. When the backlight color is monochrome, it can be white, red, green, blue, or other colors. In this case, the backlighting unit can consist of only one LED, which is connected in series in the circuits shown in Figures 1 and 3 to emit light. When the backlight color is multi-colored, richer color effects can be achieved. For example, the color can gradually change, making the backlighting effect more dazzling. In this case, the backlighting unit can include at least two LEDs that emit light of different colors. The LEDs of different colors can emit a single color or mix to emit a new color, thus making the colors richer.

[0134] The following section introduces the keyboard backlight circuit with multi-color lighting effects.

[0135] The multi-color backlight circuit for keyboards is structurally similar to the keyboard backlight circuit described above. The difference lies in that the light-emitting unit of the multi-color backlight circuit includes at least two LEDs of different colors. One LED is connected in series with a first resistor, allowing current to flow unidirectionally through the first resistor. It emits light under the drive of a signal applied to scan line 10. The other LEDs are controlled by other control circuits to produce various lighting effects in conjunction with the LED connected in series with the first resistor. For ease of description, the LEDs in the light-emitting unit other than the one connected in series with the first resistor are referred to as other LEDs.

[0136] In this way, by using the light-emitting diodes connected in series with the first resistor and other light-emitting diodes of different colors, a variety of colors can be produced, creating a more diverse light-emitting effect. Optionally, the light-emitting unit includes three light-emitting diodes, which emit red, green, and blue light (the three primary colors of light) respectively, thus allowing for the creation of virtually any color that the human eye can perceive.

[0137] In some embodiments, the light emitted by the LED connected in series with the first resistor is red. It is understood that, due to the need for key detection, the LED connected in series with the first resistor must be at a high level for a certain period, which means that the LED will inevitably light up during key detection, even if it is not required to light up during that time under a preset lighting control mode. Since the human eye is less sensitive to red light than other colors (blue and green), setting the color of the light emitted by the LED connected in series with the first resistor to red can reduce the visual attention drawn to the LED during key detection, thus not affecting the keyboard's lighting according to the predetermined lighting mode.

[0138] The key input device also includes a control circuit 3 for controlling the illumination of other LEDs. Each of the other LEDs is located in a separate control circuit, so that each LED can be independently controlled to emit light. In some embodiments, as shown in FIG10, the control circuit 3 includes a third resistor (R19 in the figure), a third voltage terminal 30 for inputting a driving voltage signal, and a fourth voltage terminal 31 for grounding. The LED (D10 in the figure) and the third resistor are connected in series between the third voltage terminal 30 and the fourth voltage terminal 31. Obviously, the positive terminal of the LED is close to the third voltage terminal 30, so that the LED can emit light under the voltage drive of the third voltage terminal 30.

[0139] The first voltage terminal 100, the third voltage terminal 30, and the voltage output terminal 110 are all connected to the chip's I / O interface. The chip inputs drive voltage signals to multiple scan lines 10 and detects the voltage signal at the voltage output terminal 110 of the output line 11. Simultaneously, the chip inputs a drive voltage signal to the third voltage terminal 30 according to control instructions to control the LEDs in the control circuit to emit light. It is understood that the number of chips is not limited to one; for example, more chips can be used when the number of I / O interfaces is insufficient. Furthermore, the keyboard backlight circuit and the control circuit 3 can share a chip or be set up with separate chips.

[0140] The specific structure of the keyboard backlight circuit can be found in the description above, and will not be repeated here.

[0141] It is understandable that the keyboard backlight circuit driving method for a multi-color luminous effect can use either the first or the second keyboard backlight circuit driving method described above. Compared to the first method, the second method, because the high-level signal on scan line 10 is applied for a shorter time during key detection and the brightness is relatively weaker, better prevents the human eye from observing the light from the LED connected in series with the first resistor during key detection. Simultaneously, it does not affect the luminous effect of the light-emitting unit within the first time period t10. It is also understandable that the second method, combined with the fact that the light from the LED connected in series with the first resistor is red (which is insensitive to the human eye), can more effectively prevent the human eye from observing the light from the LED during key detection.

[0142] The keyboard backlight circuit driving method with multi-color light emission effect can directly apply the second keyboard backlight circuit driving method described above, including the first key detection step and the second key detection step. The content that is the same as above will not be repeated. The following section describes the parts where there are differences.

[0143] Since the light-emitting unit includes at least two light-emitting diodes, in step A1 above, during the first time period t10, a high-level driving voltage is input to the first voltage terminal 100 of the scan line 10 and the third voltage terminal 30 of the control circuit 3 according to the control signal, so as to control all the light-emitting diodes to emit light according to the control signal. The control signal can be issued by the processor of the electronic device, which can be the light-emitting control program built into the system, or it can be a corresponding control signal generated according to the control command issued by the user. After the chip receives the corresponding control signal, it inputs a driving voltage signal to the first voltage terminal 100 and the third voltage terminal 30 of the scan line 10 according to the control signal. For example, a high-level driving voltage is applied in a certain time and sequence, so that each light-emitting diode emits light at the required time, thereby achieving a variety of light-emitting effects. For example, all the light-emitting diodes can emit light continuously to achieve a constant backlight effect, or produce changing lighting effects.

[0144] During the second time period t11, in some embodiments, other light-emitting diodes are controlled to emit light (by applying a driving voltage signal) according to a control signal, thereby improving the continuity and brightness of the light-emitting display effect and covering the light emitted by the light-emitting diode connected in series with the first resistor. In other embodiments, other light-emitting diodes can also be controlled not to emit light (by not applying a driving voltage signal). Since the second time period t11 is relatively short, it has less impact on the light-emitting display effect and is more energy-efficient.

[0145] The present invention also proposes a key input device, which includes any of the keyboard backlight circuits described above. The key input device may be a keyboard, such as the keyboard of a mobile phone or computer.

[0146] The key input device includes a key circuit board, as shown in Figure 11. The key circuit board includes a first circuit board 40 and a second circuit board 41 arranged vertically and spaced apart, and a spacer layer 42 connecting the first circuit board 40 and the second circuit board 41. The first circuit board 40 is located above the second circuit board 41 and is provided with an output line 11 and a second resistor (if present). The second circuit board 41 is provided with a scan line 10, a light-emitting diode 46 and a first resistor (not shown in the figure). Conductive lines (e.g., silver paste lines) can be provided on the first circuit board 40 and the second circuit board 41 to form the scan line 10 and the output line 11.

[0147] A push-button switch is connected between a first circuit board 40 and a second circuit board 41, as shown in Figure 11. The push-button switch includes a first contact 430 located on the first circuit board 40 and electrically connected to the output line 11, and a second contact 431 located on the second circuit board 41 and electrically connected to the scan line 10. The two contacts are spaced apart from each other, and the spacer layer 42 has a cavity 420 for exposing the first contact 430 and the second contact 431. A reset element 44 and a button 45 are correspondingly arranged above the push-button switch. The reset element 44 can be made of elastic materials such as rubber or silicone. When the button 45 is pressed, the button 45 presses down the reset element 44 and the push-button switch, so that the first contact 430 and the second contact 431 make contact, and the scan line 10 and the output line 11 are connected. When the button 45 is released, the button 45 is reset by the elastic force of the reset element 44, and the scan line 10 and the output line 11 are disconnected.

[0148] An LED 46 is disposed on the second circuit board 41. A clearance hole 400 is provided on the spacer layer 42 and the first circuit board 40 to expose the LED 46. The LED 46 is disposed within the clearance hole 400, and its light can be emitted towards the button 45. In some embodiments, the button 45 is provided with a light-transmitting area 450 made of transparent material. The light-transmitting area 450 can, for example, be consistent with the letters / graphics marked on the button 45, so that the light from the LED 46 can illuminate the letters / graphics, making it more aesthetically pleasing. The button 45 can also be made completely transparent; in this case, the portion of the button 45 other than the portion marked with letters / graphics forms the light-transmitting area 450 (i.e., the light-transmitting area 450 includes cases where the button 45 is partially transparent or completely transparent). In some other embodiments, referring to FIG12, a reflective layer 451 is provided on the inner surface of the button 45. The reflective layer 451 has a reflective surface that reflects the light of the light-emitting diode 46. The reflected light illuminates the area around the button 45, improving the aesthetics. In other embodiments, if the inner surface of the button 45 itself has a good reflective effect, the reflective layer 451 may not be provided, and the inner surface of the button 45 may be used directly as the reflective surface.

[0149] It is understandable that when the light-emitting unit includes multiple light-emitting diodes, the other diodes and the corresponding control circuits and the third resistor can be set on the second circuit board 41, or they can be set on the first circuit board 40.

[0150] Optionally, both the first circuit board 40 and the second circuit board 41 are thin-film circuits.

[0151] In this invention, only two circuit boards are needed to achieve the functions of anti-ghosting key detection and backlight display, which simplifies the structure of the circuit board, makes the circuit design of the key input device simpler, and the overall thickness of the circuit board can be reduced. In this way, the key input device can also be made smaller, which can effectively reduce the thickness of laptops and other products with high requirements for thinness and lightness, and improve product competitiveness.

[0152] The present invention also proposes an electronic device comprising any of the keyboard backlight circuits described above or any of the key input devices described above. The electronic device may be, for example, a mobile phone with keys, a laptop computer, a desktop computer, a game console, or other devices with keys.

[0153] This invention also proposes a processor-readable storage medium for storing processor-executable instructions. When these instructions are loaded and executed by the processor, they can implement any of the keyboard backlight circuit driving methods described above. It is understood that key input devices and / or electronic devices may include this processor-readable storage medium.

[0154] It should be noted that, in the absence of conflict, the various embodiments described herein can be combined with each other to obtain more implementation schemes.

[0155] The above are merely specific embodiments of the present invention, and any improvements made based on the concept of the present invention shall be considered within the scope of protection of the present invention.

Claims

1. A keyboard backlighting circuit integrated with key detection functionality, characterized by, include: Multiple scan lines (10) are arranged at intervals. Each scan line (10) has a main line (102) and multiple parallel branch lines (103) connected to the main line (102). The main line (102) has a first voltage terminal (100), and each branch line (103) has a second voltage terminal (101). A series-connected light-emitting diode and a first resistor are sequentially arranged between the connection point of the branch line (103) and the main line (102) and the second voltage terminal (101). The light-emitting diode is used to realize keyboard backlighting and allows current to conduct unidirectionally to the first resistor. Multiple output lines (11) are arranged at intervals and interleaved with the scan lines (10) to form a matrix circuit. Each output line (11) has a voltage output terminal (110) and multiple switch circuits (12) respectively connected to the branches (103) of the multiple scan lines (10). Each branch (103) is provided with a corresponding switch circuit (12). The switch circuit (12) is connected to the portion of the branch (103) located between the light-emitting diode and the first resistor. The switch circuit (12) includes a push-button switch.

2. The keyboard backlighting circuit integrated with key detection function as claimed in claim 1, wherein, The first voltage terminal (100) and the voltage output terminal (110) are both connected to the chip's IO interface. The chip inputs driving voltage signals to multiple scan lines (10) and detects the voltage signal at the voltage output terminal (110) of the output line (11). The second voltage terminal (101) is a ground voltage terminal.

3. The keyboard backlighting circuit integrated with key detection function as claimed in claim 1, wherein, The driving voltage applied to the first voltage terminal (100) is 5V, and the resistance of the first resistor is 100-1000 ohms; or, The driving voltage applied to the first voltage terminal (100) is 3.3V, and the resistance of the first resistor is 30 to 500 ohms.

4. The keyboard backlighting circuit integrated with key detection function as claimed in claim 1, wherein, All of the light-emitting diodes emit light of the same color; or, at least two light-emitting diodes emit light of different colors.

5. The keyboard backlighting circuit integrated with key detection function according to any one of claims 1 to 4, wherein, The switching circuit (12) also includes a second resistor connected in series with the push button switch.

6. The keyboard backlighting circuit integrated with key detection functionality of claim 5, wherein, The resistance of the second resistor is greater than 0.2 times the resistance of the first resistor.

7. The keyboard backlighting circuit integrated with key detection function as claimed in claim 5, wherein, The resistance of the second resistor is greater than or equal to twice the resistance of the first resistor, and less than or equal to ten times the resistance of the first resistor.

8. A method of driving a keyboard backlight circuit, the method comprising: It is executed by the keyboard backlight circuit with integrated key detection function as described in any one of claims 1 to 7, wherein the keyboard backlight circuit driving method includes the following steps: S1. A high level of a preset duration is sequentially applied to the first voltage terminal (100) of a plurality of scan lines (10), and a high level is applied to the first voltage terminal (100) of only one scan line (10) at the same time; S2. During the period when the high level is applied, detect the voltage signal of the voltage output terminal (110) of all the output lines (11) and determine whether the voltage magnitude is within the preset amplitude range; S3. When the magnitude of the voltage signal at a certain voltage output terminal (110) is within the preset amplitude range, the triggered button switch is determined by combining the voltage conditions of the high-level scan line (10) and the voltage output terminals (110) of the multiple output lines (11).

9. The method of claim 8, wherein the key backlight circuit is driven by a key backlight circuit driver. The total time from the start of applying a high level to the first scan line (10) to the end of applying a high level to the last scan line (10) is one scan cycle. The time of the scan cycle is set so that the flickering of the light-emitting diode cannot be detected by the naked eye.

10. The method of claim 9, wherein the key backlight circuit is driven by a key backlight circuit driver. The scan cycle time is no more than 41.6 ms.

11. The method of claim 9, wherein the key backlight circuit is driven by a key backlight circuit driver. In step S2, the voltage output terminal (110) of the output line (11) is detected after a preset time period following the application of a high level to the scan line (10).

12. The keyboard backlighting circuit driving method according to any one of claims 8 to 11, wherein Step S3 includes the following steps: S31. When the magnitude of the voltage signal at the voltage output terminal (110) of a certain output line (11) is within the preset amplitude range, a scan line (10) that is simultaneously supplied with a high level is acquired. S32. Identify the scan connected to the required output line (11) and simultaneously applied with a high level. The push-button switch between the lines (10) is the push-button switch that is triggered. The qualified output line (11) refers to the output line (11) corresponding to the voltage output terminal (110) where the magnitude of the detected voltage signal is within the preset amplitude range.

13. A key input device, characterized by The keyboard backlight circuit includes the integrated key detection function as described in any one of claims 1 to 7.

14. The key input device of claim 13, wherein include: The first circuit board (40) is provided with the output line (11); The second circuit board (41) is provided with the scan line (10), the light-emitting diode and the first resistor; and, The push button switch includes a first contact (430) located on the first circuit board (40) and electrically connected to the output line (11) and a second contact (431) located on the second circuit board (41) and electrically connected to the scan line (10), wherein the first contact (430) and the second contact (431) are arranged at a distance from each other. A reset component (44) and a button (45) are respectively arranged above the push button switch. The light-emitting diode is located below the button (45) and exposed on the first circuit board (40) to emit light toward the button (45). The first circuit board (40) is closer to the button (45) than the second circuit board (41).

15. The key input device of claim 14, wherein It also includes a spacer layer (42) connecting the first circuit board (40) and the second circuit board (41), wherein the spacer layer (42) and the first circuit board (40) are provided with a clearance hole (400), and the light-emitting diode is located in the clearance hole (400).

16. The key input device of claim 14, wherein The button (45) is provided with a light-transmitting area (450) for the light from the light-emitting diode to pass through; or, The inner wall of the button (45) is provided with a reflective surface.

17. A method of driving a keyboard backlight circuit, the method comprising: The keyboard backlight circuit driving method is executed by a keyboard backlight circuit with integrated key detection function. The keyboard backlight circuit with integrated key detection function includes multiple scan lines (10) arranged at intervals and multiple output lines (11) arranged at intervals. The multiple output lines (11) and the multiple scan lines (10) are arranged in an alternating matrix circuit. The scan lines (10) are provided with light-emitting diodes for keyboard backlighting. The output lines (11) have multiple switch circuits (12) respectively connected to the multiple scan lines (10). The switch circuits (12) include key switches. The keyboard backlight circuit driving method includes the following steps: A1. Drive the LED to emit light as needed during the first time period t10; A2. During the second time period t11, perform button detection; A3. Repeat steps A1 and A2 in sequence.

18. The method of claim 17, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, turning on the light source. The first time period t10 and the second time period t11 form a light emission period T2, and the first time period t10 is greater than or equal to the second time period t11.

19. The method of claim 18, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, turning on the light source. The time ratio of the first time period t10 to the light emission period T2 is not less than 80%, and the time ratio of the first time period t10 to the light emission period T2 is not greater than 99.9%.

20. The method of claim 17, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, turning on the light source. In step A1, during the first time period, a driving voltage signal is input to the first voltage terminal (100) of all the scan lines (10) according to the control signal, so as to drive all the light-emitting diodes to continuously emit light or produce a lamp effect.

21. The method of claim 17, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then turning on the light source. The duration of the second time period t11 is less than or equal to 41.6ms.

22. The method of claim 21, wherein the method further comprises: The first time period t10 and the second time period t11 form a light emission period T2, the duration of the light emission period T2 is less than or equal to 41.6 ms, and the duration of the second time period t11 is less than or equal to 15 ms.

23. The keyboard backlight circuit driving method as described in claim 17, characterized in that, In step A2, the key detection includes: A21. A high level of a preset duration is sequentially applied to the first voltage terminal (100) of a plurality of scan lines (10), and a high level is applied to the first voltage terminal (100) of only one scan line (10) at the same time; A22. During the period when the high level is applied, the voltage signal of the voltage output terminal (110) of the multiple output lines (11) is detected, and it is determined whether the voltage magnitude is within the preset amplitude range. A23. When the magnitude of the voltage signal detected at a certain voltage output terminal (110) is within a preset amplitude value. When the range is within the specified range, the triggered button switch is determined by combining the voltage conditions of the high-level scan line (10) and the voltage output terminals (110) of the multiple output lines (11).

24. The method of claim 23, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, turning on the light source. Step A23 includes the following steps: ​ A231. When the magnitude of the voltage signal at the voltage output terminal (110) of a certain output line (11) is within the preset amplitude range, a scan line (10) that is simultaneously supplied with a high level is acquired. A232. Identify the push-button switch connected between the qualified output line (11) and the scan line (10) that is simultaneously supplied with a high level. This push-button switch is the triggered push-button switch. The qualified output line (11) refers to the output line (11) corresponding to the voltage output terminal (110) whose detected voltage signal is within the preset amplitude range.

25. The method of claim 17 to 24, wherein the method further comprises: The scan line (10) has a main line (102) and multiple parallel branch lines (103) connected to the main line (102). The main line (102) has a first voltage terminal (100), and the branch lines (103) have a second voltage terminal (101), which is a ground voltage terminal. A light-emitting diode and a first resistor are connected in series between the connection point of the branch line (103) and the main line (102) and the second voltage terminal (101). The light-emitting diode causes current to flow unidirectionally towards the first resistor. The output line (11) has a voltage output terminal (110) and a plurality of switching circuits (12) that are respectively connected to the branches (103) of the plurality of scanning lines (10). Each branch (103) is provided with a corresponding switching circuit (12). The switching circuit (12) is connected to the portion of the branch (103) located between the light-emitting diode and the first resistor.

26. The method of claim 25, wherein the method further comprises: The switching circuit (12) also includes a second resistor connected in series with the push button switch.

27. The method of claim 26, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then applying the first voltage to the first light source and the second voltage to the second light source. The resistance of the second resistor is less than or equal to 10 times the resistance of the first resistor, and greater than or equal to 0.2 times the resistance of the first resistor.

28. A keyboard backlighting circuit integrated with key detection functionality, characterized by, include: Multiple scan lines (10) are arranged at intervals. Each scan line (10) has a main line (102) and multiple parallel branch lines (103) connected to the main line (102). The main line (102) has a first voltage terminal (100), and the branch line (103) has a second voltage terminal (101). A light-emitting unit and a first resistor are sequentially arranged between the connection point of the branch line (103) and the main line (102) and the second voltage terminal (101). The light-emitting unit is used for keyboard backlighting and includes at least two light-emitting diodes emitting different colors of light. One of the light-emitting diodes is connected in series with the first resistor, allowing current to flow unidirectionally towards the first resistor. Multiple output lines (11) are arranged at intervals and interleaved with the scan lines (10) to form a matrix circuit. Each output line (11) has a voltage output terminal (110) and multiple switch circuits (12) that are respectively connected to the branches (103) of the multiple scan lines (10). Each branch (103) is provided with a corresponding switch circuit (12). The switch circuit (12) and the branch (103) connected thereto are connected to the portion between the light-emitting diode and the first resistor. The switch circuit (12) includes a push-button switch.

29. The integrated key detection function keyboard backlighting circuit of claim 28, wherein, The light-emitting unit includes three light-emitting diodes, which emit red, green and blue light respectively.

30. The integrated key detection function keyboard backlighting circuit of claim 28, wherein, The light emitted by the LED connected in series with the first resistor is red.

31. The integrated key detection function keyboard backlighting circuit of claim 28, wherein, The light-emitting unit, apart from the light-emitting diode connected in series with the first resistor, consists of other light-emitting diodes. Each of these other light-emitting diodes is located in a control circuit. The control circuit includes a third resistor, a third voltage terminal (30) for inputting a driving voltage signal, and a fourth voltage terminal (31) for grounding. The light-emitting diode and the third resistor are connected in series between the third voltage terminal (30) and the fourth voltage terminal (31).

32. The integrated key detection function keyboard backlighting circuit of claim 31, wherein, The first voltage terminal (100), the third voltage terminal (30), and the voltage output terminal (110) are all connected to the chip's IO interface. The chip can input driving voltage signals to multiple scan lines (10) and detect the voltage signal of the voltage output terminal (110) of the output line (11). The second voltage terminal (101) is a ground voltage terminal.

33. The integrated key detection function keyboard backlighting circuit of any one of claims 28 to 32, wherein, The switching circuit (12) also includes a second resistor connected in series with the push button switch.

34. The integrated key detection function keyboard backlighting circuit of claim 33, wherein, The resistance of the second resistor is greater than that of the first resistor.

35. The integrated key detection function keyboard backlighting circuit of claim 33, wherein, The resistance of the second resistor is greater than or equal to twice the resistance of the first resistor, and less than or equal to ten times the resistance of the first resistor.

36. A method of driving a keyboard backlight circuit, the method comprising: Performed via the keyboard backlight circuit with integrated key detection function as described in any one of claims 28 to 35, the method includes the following steps: A1. Drive the LED to emit light as needed during the first time period t10; A2. During the second time period t11, perform button detection; A3. Repeat steps A1 and A2 in sequence.

37. The method of claim 36, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then applying the first voltage to the first light source and the second voltage to the second light source. In step A1, during the first time period t10, a driving voltage signal is input to the first voltage terminal (100) of the scan line (10) and the third voltage terminal (30) of the control circuit according to the control signal, so as to control all light-emitting diodes to emit light according to the control signal.

38. The method of claim 37, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then applying the first voltage to the first light source and the second voltage to the second light source. During the second time period t11, other LEDs are controlled to light up or not light up according to the control signal.

39. The keyboard backlight circuit driving method as described in claim 36, characterized in that, The first time period t10 is greater than or equal to the second time period t11.

40. The method of claim 39, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, turning on the light source. 40 The time ratio of the first time period t10 to the light emission period T2 is not less than 80%; the time ratio of the first time period t10 to the light emission period T2 is not greater than 99.9%.

41. The keyboard backlight circuit driving method as described in claim 36, characterized in that, The duration of the second time period t11 is no more than 41.6ms.

42. The method of claim 41, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then applying the first voltage to the first light source and the second voltage to the second light source. The first time period t10 and the second time period t11 form a light emission period T2, the duration of the light emission period T2 is less than or equal to 41.6 ms, and the duration of the second time period t11 is less than or equal to 15 ms.

43. The method of claim 36, 37, 38, 39, 40, 41 or 42, wherein the method further comprises: In step A2, the key detection includes: A21. A preset time is applied to the first voltage terminal (100) of the plurality of scan lines (10) in sequence. A high level is applied, and at the same time, only the first voltage terminal (100) of one scan line (10) is applied; A22. During the period when the high level is applied, the voltage signal of the voltage output terminal (110) of the multiple output lines (11) is detected, and it is determined whether the voltage magnitude is within the preset amplitude range. A23. When the magnitude of the voltage signal at a certain voltage output terminal (110) is within the preset amplitude range, the triggered button switch is determined by combining the voltage conditions of the high-level scan line (10) and the voltage output terminals (110) of the multiple output lines (11).

44. The method of claim 43, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, applying the first voltage to the first light source and the second voltage to the second light source. The duration of each high-level input on any of the scan lines (10) is not less than 50 microseconds.

45. The method of claim 44, wherein the method further comprises: determining whether the key is pressed; and if the key is pressed, then applying the first voltage to the first light source and the second voltage to the second light source. In step A22, the voltage output terminal (110) of the output line (11) is detected after a preset time period following the application of a high level to the scan line (10). The preset time period is greater than or equal to 30 microseconds.

46. The method of claim 44, wherein the method further comprises: determining whether the keyboard is in a closed position; and if the keyboard is in the closed position, then applying the first voltage to the first and second light sources. 46 Step A23 includes the following steps: A231. When the magnitude of the voltage signal at the voltage output terminal (110) of a certain output line (11) is within the preset amplitude range, a scan line (10) that is simultaneously supplied with a high level is acquired. A232. Identify the push-button switch connected between the qualified output line (11) and the scan line (10) that is simultaneously connected to a high level. This push-button switch is the triggered push-button switch. The qualified output line (11) refers to the output line (11) corresponding to the voltage output terminal (110) whose detected voltage signal is within the preset amplitude range.

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