A keyboard backlight circuit with integrated key detection function and its driving method

Abstract

The present invention discloses a keyboard backlight circuit with an integrated key detection function and a keyboard backlight circuit driving method. The keyboard backlight circuit with an integrated key detection function includes multiple scan lines and multiple output lines. The multiple scan lines are arranged at intervals. A light-emitting unit and a first resistor are sequentially arranged between a first voltage terminal and a second voltage terminal of the scan line. The light-emitting unit is used for keyboard backlighting and includes at least two light-emitting diodes emitting light of different colors, one of which is connected in series with a first resistor and causes current to flow unidirectionally toward the first resistor. The multiple output lines are arranged at intervals. The output lines have voltage output terminals and multiple switch circuits respectively connected to the multiple scan lines. The switch circuits are connected to the portions of the scan lines connected thereto located between the light-emitting diodes and the first resistor. The switch circuits include key switches. The keyboard backlight circuit with an integrated key detection function of the present invention can achieve a keyboard color backlight effect and key detection.

Description

Technical Field

[0001] The present invention relates to an information input device, and in particular to a keyboard backlight circuit with integrated key detection function and a keyboard backlight circuit driving method. Background Art

[0002] With the development of technology, electronic devices have become more and more 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.

[0003] To make keyboards easier to use in dark or dim environments, some keyboards have a backlight function. This function uses LEDs (light-emitting diodes) to illuminate the keys or the area around the keys, allowing users to identify the location of each key and accurately operate the keys. The keyboard backlight function is achieved through the keyboard's backlight circuit. The backlight circuit has LEDs corresponding to the key positions, and the backlight function is achieved by controlling the LEDs to emit light.

[0004] Furthermore, in order to receive key information, the keyboard is also provided with a key detection circuit, which identifies which key is pressed through the key detection circuit.

[0005] In other words, keyboards with backlighting require both backlighting circuitry and key detection circuitry. This results in a complex circuit layout, multiple circuit board layers, or the need for multiple stacked circuit boards, resulting in a thicker keyboard and higher cost. For keyboards with color backlighting, the circuit board layout becomes even more complex, further increasing the thickness of the keyboard.

[0006] For some products that pursue thinness and lightness, complex circuit board design will make the circuit board as a whole too thick, which cannot meet the requirements of thinness and lightness of laptops.

[0007] 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. Summary of the Invention

[0008] The purpose of the present invention is to provide a keyboard backlight circuit and a keyboard backlight circuit driving method with integrated key detection function, which can realize the key detection function while achieving the color backlight effect of the keyboard.

[0009] To achieve the above-mentioned object, the present invention provides a keyboard backlight circuit with integrated key detection function, comprising:

[0010] a plurality of scan lines, the plurality of scan lines being arranged at intervals, the scan lines comprising a main line and a plurality of parallel branch lines connected to the main line, the main line having a first voltage terminal, the branch lines having a second voltage terminal, a light-emitting unit and a first resistor being sequentially disposed between a connection position between the branch lines and the main line and the second voltage terminal, the light-emitting unit being used for keyboard backlighting and comprising at least two light-emitting diodes emitting light of different colors, one of the light-emitting diodes being connected in series with a first resistor so that current is unidirectionally conducted toward the first resistor; and,

[0011] A plurality of output lines are arranged at intervals and staggered with the scan lines to form a matrix circuit. The output lines have voltage output terminals and a plurality of switch circuits respectively connected to the branches of the plurality of scan lines. Each branch line is provided with a corresponding switch circuit. The switch circuit is connected to a portion of the branch line connected thereto located between the light-emitting diode and the first resistor. The switch circuit includes a key switch.

[0012] Furthermore, the light emitting unit includes three light emitting diodes, and the three light emitting diodes emit red, green and blue light respectively.

[0013] Furthermore, the light emitted by the light emitting diode connected in series with the first resistor is red.

[0014] Furthermore, the light-emitting diodes of the light-emitting unit other than the light-emitting diode connected in series with the first resistor are other light-emitting diodes, and each of the other light-emitting diodes is arranged in a control circuit, and the control circuit includes a third resistor, a third voltage terminal for passing a driving voltage signal, and a fourth voltage terminal for grounding, and the light-emitting diode and the third resistor are connected in series between the third voltage terminal and the fourth voltage terminal in sequence.

[0015] Furthermore, the first voltage terminal, the third voltage terminal and the voltage output terminal are all connected to the IO interface of the chip, and the chip can input driving voltage signals to multiple scanning lines and detect the voltage signal of the voltage output terminal of the output line; the second voltage terminal is the ground voltage terminal.

[0016] Furthermore, the switch circuit further includes a second resistor connected in series with the key switch.

[0017] Furthermore, the resistance of the second resistor is greater than that of the first resistor.

[0018] Furthermore, the resistance of the second resistor is greater than or equal to 2 times the resistance of the first resistor and less than or equal to 10 times the resistance of the first resistor.

[0019] In a second aspect, the present invention provides a keyboard backlight circuit driving method, which is performed by the keyboard backlight circuit with integrated key detection function as described above, comprising the following steps:

[0020] A1. Driving the light emitting diode on demand within the first time period t10;

[0021] A2. During the second time period t11, key detection is performed;

[0022] A3. Repeat steps A1 and A2 in sequence.

[0023] Furthermore, in the step A1, a driving voltage signal is input to the first voltage terminal of the scan line and the third voltage terminal of the control circuit according to the control signal within the first time period t10, so as to control all the light emitting diodes to emit light according to the control signal.

[0024] Furthermore, in the second time period t11, other light emitting diodes are controlled to emit light or not according to the control signal.

[0025] Furthermore, the first time period t10 is greater than or equal to the second time period t11.

[0026] Furthermore, the first time period t10 and the light-emitting period T2 account for no less than 80% of the time; the first time period t10 and the light-emitting period T2 account for no more than 99.9% of the time.

[0027] Furthermore, the duration of the second time period t11 does not exceed 41.6 ms.

[0028] Furthermore, the first time period t10 and the second time period t11 form a lighting cycle T2, the duration of the lighting cycle 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.

[0029] Furthermore, in step A2, performing key detection includes:

[0030] A21. Sequentially pass a high level for a preset duration to the first voltage terminal of the plurality of scan lines, and at the same time only pass a high level to the first voltage terminal of one scan line;

[0031] A22. Detecting the voltage signals at the voltage output terminals of the plurality of output lines during the high-level period to determine whether a voltage signal has a voltage magnitude within a preset amplitude range;

[0032] A23. When it is detected that the voltage signal of a certain voltage output terminal is within a preset amplitude value range, the triggered key switch is determined by combining the voltage conditions of the high-level scan line and the voltage output terminals of the multiple output lines.

[0033] Furthermore, the time for any of the scan lines to input a high level each time is not shorter than 50 microseconds.

[0034] Furthermore, in the step A22, the voltage output end of the output line is detected after a preset time period after the high level is applied to the scan line, and the preset time period is greater than or equal to 30 microseconds.

[0035] Furthermore, the step A23 includes the following steps:

[0036] A231. When the voltage signal at the voltage output terminal of a certain output line is detected to be within a preset amplitude range, a high-level scan line is obtained at the same time;

[0037] A232. Identify the key switch connected between the output line that meets the requirements and the scan line that is fed with a high level at the same time. The key switch is the triggered key switch. The output line that meets the requirements refers to the output line corresponding to the voltage output end whose detected voltage signal is within the preset amplitude value range.

[0038] Compared with the prior art, the present invention has the following beneficial effects: according to some embodiments of the present invention, a keyboard backlight circuit with integrated key detection function is provided with a light-emitting unit for keyboard backlight, and the light-emitting unit includes at least two light-emitting diodes that emit light of different colors, which can achieve a colorful backlight effect. The keyboard backlight circuit also includes a scan line, an output line and a switching circuit connected between the scan line and the output line, which can achieve key detection. In addition, an light-emitting diode of the light-emitting unit is connected in series to the scan line, thereby achieving an anti-ghost key effect while achieving key backlight. In this way, the keyboard backlight circuit integrates the key detection function, simplifies the circuit structure, and is conducive to reducing the thickness of the key input device or other equipment with the keyboard backlight circuit, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a circuit diagram of a keyboard backlight circuit with integrated key detection function according to an embodiment of the present invention.

[0040] Figure 2 yes Figure 1 The circuit shown is a schematic diagram for preventing false detection.

[0041] Figure 3 This is a circuit diagram of a keyboard backlight circuit with an integrated key detection function in an embodiment of the present invention. In the diagram, a second resistor is provided in the switch circuit.

[0042] Figure 4 This is a timing diagram of applying a high level to each scan line during key detection in an embodiment of the present invention, and shows two scan cycles.

[0043] Figure 5 This is a timing diagram of a lighting cycle in an embodiment of the present invention.

[0044] Figure 6 This is a timing diagram of a lighting cycle in an embodiment of the present invention.

[0045] Figure 7 This is a timing diagram of a lighting cycle in an embodiment of the present invention.

[0046] Figure 8 This is a timing diagram of the power-on period of each scan line in an embodiment of the present invention.

[0047] Figure 9 This is a timing diagram of the power-on period of each scan line in an embodiment of the present invention.

[0048] Figure 10 4 is a circuit diagram of a control circuit according to an embodiment of the present invention.

[0049] Figure 11 It is a structural diagram of a key input device according to an embodiment of the present invention.

[0050] Figure 12 It is a structural diagram of a key input device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0052] As used herein, the terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0053] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0054] The present invention proposes a keyboard backlight circuit with an integrated key detection function (hereinafter referred to as a keyboard backlight circuit), which can be used in a keyboard or an electronic device with multiple keys. The keyboard backlight circuit can realize the backlight of the keyboard and can also detect the keys to determine which key of the device is pressed.

[0055] like Figure 1 As shown, the keyboard backlight circuit corresponding to an embodiment of the present invention includes a plurality of scan lines 10 and a plurality of output lines 11. The plurality of scan lines 10 are arranged at intervals, and the plurality of output lines 11 are also arranged at intervals. The scan lines 10 and the output lines 11 are staggered to form a matrix circuit. Figure 1 As shown, Figure 1 The number of scan lines 10 and output lines 11 shown is 3. For the convenience of description, the three scan lines 10 from top to bottom are respectively referred to as the first scan line 10a, the second scan line 10b and the third scan line 10c, and the three output lines 11 from left to right are respectively referred to as the first output line 11a, the second output line 11b and the third output line 11c.

[0056] It should be noted that, herein, "plurality" or "multiple" or similar expressions indicate that the number is at least two, i.e., "plurality" means two or more. Therefore, in other embodiments, the number of scan lines 10 and output lines 11 may be two or more than three. It should be further noted that, although the number of scan lines 10 and output lines 11 is the same in the illustrated embodiment, this is not necessarily the case. The number of the two can be different, for example, one can be two and the other can be three, etc.

[0057] The scanning line 10 has a first voltage terminal 100 and a second voltage terminal 101. The number of the second voltage terminals 101 can be multiple, for example Figure 1 In the illustrated embodiment, the scan line 10 includes a main line 102 and a plurality of branch lines 103 connected to the main line 102. The plurality of branch lines 103 are arranged in parallel. Each branch line 103 is provided with a second voltage terminal 101. A light-emitting diode and a first resistor are sequentially arranged between the connection position of the branch line 103 and the main line 102 and the second voltage terminal 101. The light-emitting diode and the first resistor are connected in series. Figure 1D1 to D9 are light-emitting diodes, and R1 to R9 are first resistors. The light-emitting diodes conduct current unidirectionally toward the second voltage terminal 101. That is, the current input from the first voltage terminal 100 flows into the anode of the light-emitting diode, then flows out from the cathode of the light-emitting diode and flows through the first resistor, causing the light-emitting diode to emit light. It is understood that due to the unidirectional conduction characteristic of the light-emitting diode, current cannot flow from the cathode to the anode.

[0058] The output line 11 has a voltage output terminal 110 and multiple switch circuits 12 respectively connected to the multiple scan lines 10. Specifically, the multiple switch circuits 12 are respectively connected to the branches 103 of the multiple scan lines 10. More specifically, the switch circuits 12 are connected to the portion of the branch 103 located between the light-emitting diode and the first resistor. The 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 key switch, Figure 1 SW1 to SW9 are key switches, which correspond to the position of the key (usually located below the key). When the key is pressed, the key moves downward, thereby triggering the key switch to close and turn on the switch circuit 12. Conversely, when the key switch is released, the key is reset and the key switch is turned off.

[0059] The first voltage terminal 100 of the scanning line 10 is used to pass a driving voltage signal. When a high-level driving voltage is applied to the first voltage terminal 100 of the scanning line 100, the light-emitting diode is driven to emit light. The light-emitting diode can illuminate the key, thereby acting as a keyboard backlight. Optionally, the light-emitting diode is arranged adjacent to the key switch and corresponding to the key, for example, it can be located below the key. In some embodiments, the key is at least partially transparent, for example, the part that displays the letters can be set to transparent, so that the light-emitting diode can illuminate the corresponding letter. In some embodiments, the key can be fully transparent to present a crystal clear feeling and improve the aesthetics. In some embodiments, the key is opaque, and its inner wall is provided with a reflective surface (for example, coated with a reflective coating), which can reflect the light of the light-emitting diode, so that the bottom of the key is illuminated, creating a sense of light around the key.

[0060] It can be understood that when the key switch (for example, SW1) is pressed and a high-level driving voltage is applied to the first voltage terminal 100 of the scan line 10 (for example, the first scan line 10a) connected thereto, the voltage output terminal 110 of the output line 11 (for example, the first output line 11a) connected to the key switch will detect a voltage signal, which is also reflected as a high level. Obviously, due to the voltage dividing effect of the light-emitting diode and the first resistor, etc., the voltage at the voltage output terminal 110 will be lower than the voltage at the first voltage terminal 100, but compared to the case where the key switch is disconnected, it is still reflected as a high level, but it is smaller than the high level of the first voltage terminal 100. Therefore, when a voltage signal whose size is within a preset range is detected at the voltage output terminal 110 of the output line 11, it indicates that a key switch is pressed.

[0061] Theoretically, as long as the key switch is not pressed, the voltage signal at the voltage output terminal 110 is always 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 key is pressed.

[0062] In some embodiments, in order to reduce interference caused by the external environment and improve the accuracy of detection, the preset range can be a range greater than 0V. It is understandable that the voltage magnitude of the voltage output terminal 110 after pressing the key can be obtained by calculating the forward voltage value of the light-emitting diode, the input voltage of the first voltage terminal 110 of the scanning line and the line resistance, or it can be obtained by actual measurement. In actual implementation, even if the detected voltage value is less than the calculated voltage value or the measured voltage value, as long as it is within the allowable amplitude range, it can be considered that the key is pressed to ensure the sensitivity of the detection result. The allowable amplitude range can be used as a preset range for judging the voltage signal magnitude. The voltage value obtained by calculation or actual measurement can be used as a basis for judging whether the voltage output terminal 110 has a voltage within the preset range. When the voltage output terminal 110 detects a voltage signal whose voltage magnitude is within the preset amplitude value range, it indicates that a key is pressed. Optionally, when a voltage signal with a voltage greater than or equal to a fixed value is detected, it indicates that a key switch is pressed, that is, the preset range is a voltage signal greater than or equal to a fixed value. The voltage signal can be less than a certain amplitude of the calculated or measured voltage value, or it can be equal to the calculated or measured voltage value.

[0063] When performing key detection, a high-level driving voltage is applied to the first voltage terminal 100 of each scanning line 10 in turn, and the voltage output terminal 110 of each output line 11 is detected during the period of applying the high level. When a voltage output terminal 110 detects a voltage within a preset amplitude value range, it indicates that the key switch connected between the output line 11 and the scanning line 10 applied with the high level is pressed (i.e., triggered), so that the position information of the pressed key can be obtained, thereby realizing key detection.

[0064] 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 key 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 key 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 key switches SW1 and SW2 are pressed simultaneously. Similarly, by combining the voltages of the voltage output terminals 110 of the scan line 10 supplied with a high level and the multiple output lines 11, the location of the pressed key can be determined, thus achieving key detection.

[0065] Since the light-emitting diodes are connected in series in the scanning line 10, the unidirectional conduction characteristics of the light-emitting diodes can be used to achieve the anti-ghosting effect. For example, when the second scanning line 10b is supplied with current (i.e., a high-level driving voltage is supplied), and the key switches SW1, SW2, and SW4 are pressed at the same time, only the voltage output end of the first output line 11a can detect a voltage within the preset amplitude value range. Due to the unidirectional conduction effect of the light-emitting diode D1, the current cannot flow out of the first output line 11a. Figure 2 The dotted line shown flows into the second output line 11b, so that the voltage output terminal 110 of the second output line 11b detects a high level. It can be understood that when the light emitting diode is not provided, the current can flow along Figure 2 The dotted line shown flows, so that the first output line 11a and the second output line 11b both output a high level. At this time, the key switch SW5 that is not pressed may be mistakenly judged as pressed. Therefore, the above-mentioned keyboard backlight circuit can prevent false detection.

[0066] It is understood that the above circuit structure design not only achieves the key luminous effect but also provides an anti-ghosting function, thereby simplifying the circuit structure and helping to reduce costs. Furthermore, the simplified circuit structure can reduce the number of layers in the circuit board of the key output device, thereby reducing the thickness of the key input device and achieving a lighter and thinner electronic device.

[0067] The keyboard backlight circuit includes a chip, and the first voltage terminal 100 and the voltage output terminal 110 are both connected to the IO interface of the chip. The chip can input a driving voltage signal to multiple scanning 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.

[0068] Optionally, the second voltage terminal 101 is a ground voltage terminal.

[0069] In some embodiments, the resistance of the first resistor is 100-1000 ohms, and the driving voltage input to the first voltage terminal 100 is approximately 5V. Setting the resistance of the first resistor to 100-1000 ohms can result in a current of 1-10mA flowing through the LED, which meets the current requirements of most LEDs used in keyboards. In other embodiments, the driving voltage input to the first voltage terminal 100 is approximately 3.3V. In this case, the resistance of the first resistor can be selected to be 30-500 ohms to ensure reliable LED illumination.

[0070] The resistance value of the first resistor can be adjusted according to the current and voltage parameters actually required for the normal operation of the light emitting diode, so that the light emitting diode can emit light reliably.

[0071] In some embodiments, as Figure 3 As shown, the switch circuit 12 further includes a second resistor connected in series with the key switch. Figure 3 The R10 to R18 indicated in the figure are the second resistors, the resistance of which is greater than 0.2 times of the first resistor, that is, the ratio of the resistance of the second resistor to the resistance of the first resistor is greater than 0.2, so as to ensure the reliability of the light emitting diode during the key pressing process. Figure 1 In the embodiment shown, when two or more key switches on the same output line 11 are pressed simultaneously, the first resistors corresponding to the pressed key switches will be connected in parallel. The resistance of the parallel connection is smaller than the resistance of the first resistor alone, so that the resistance for voltage division with the light-emitting diode becomes smaller, and the current and voltage acting on the light-emitting diode will become 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, SW1 and SW4 are pressed simultaneously. When the resistance values of the first resistors R1 and R4 are the same, the resistance of the two first resistors connected in parallel will be only half of the original value. 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 key switches are pressed at the same time, the smaller the resistance value of the voltage divided by the light-emitting diode will be. In this way, the light-emitting diode may be burned out due to excessive current flowing through the light-emitting diode, or the brightness may be too high, shortening its service life.

[0072] This problem can be solved by providing a second resistor in series with the key switch in the switch circuit 12. Figure 3 In the illustrated embodiment, when multiple keys on the same output line 10 are pressed simultaneously, the presence of the second resistor causes the resistance of the resistor ultimately dividing the voltage with the light-emitting diode to decrease relatively less, thereby ensuring the stability of the current flowing through the light-emitting diode when the key is pressed and reducing the current increase. This facilitates reliable light emission from the light-emitting diode, resulting in a more consistent and stable light emission effect, and also helps extend its service life. For example, when a high level is input to the first voltage terminal 100 of the first scan line 10a and the key switches SW1 and SW4 are pressed simultaneously, the first resistor R1 is connected in parallel with the resistors R10, R13, and R4. Since the resistance of the resistors R10 and R13 is greater than 0.2 times the resistance of the resistors R1 and R4, the parallel resistance is greater than the resistance of only R1 and R4 in parallel, reducing the increase in the current flowing through the light-emitting diode.

[0073] To further ensure the stability of the light emitting diode's 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 2 times the resistance of the first resistor, so that after pressing the switch, the total current impact is less than 33%, the change in the current flowing through the light emitting diode is smaller, and there is no significant optical or electrical impact on the light emitting diode, thereby effectively ensuring the stability of the light emitting diode's emission and the reliability of its use.

[0074] Optionally, the resistance of the second resistor does not exceed 10 times the resistance of the first resistor. Because the detection input of the output line is generally in a high-resistance state, when the resistance of the detection end is too large, it will affect the accuracy of the detection value. Setting the resistance of the second resistor to be less than 10 times the resistance of the first resistor is conducive to improving the accuracy of the detection value.

[0075] Optionally, the first resistor and the second resistor may be ordinary resistors, carbon ink resistors, silver paste printed resistors, or other resistors that can be used for thin film circuits.

[0076] The color of the light emitted by the LEDs is not limited and can be, for example, white, red, blue, or green. Optionally, all LEDs can emit the same color, or at least two LEDs can emit light of different colors to produce a richer lighting effect. The colors of the LEDs in different positions can be set as needed.

[0077] Next, a method for driving the backlight using the keyboard backlight circuit described above will be described.

[0078] The keyboard backlight circuit driving method includes the following steps:

[0079] S1. A high level of a preset duration is applied to the first voltage terminals 100 of multiple scan lines 10 in sequence, and a high level is applied to the first voltage terminal 100 of only one scan line 10 at a time, that is, a high level is applied to at most one scan line 10 at a time.

[0080] S2. Detect the voltage signals of the voltage output terminals 110 of the plurality of output lines 11 during the period of high level, and determine whether there is a voltage signal whose voltage magnitude is within a preset amplitude value range, that is, determine whether the voltage magnitude of the detected voltage signal is within the preset amplitude value range.

[0081] S3. When it is detected that the voltage signal of a certain voltage output terminal 110 is within the preset amplitude value range, the triggered key switch is determined in combination with the voltage conditions of the voltage output terminal 110 of the high-level scan line 10 and the multiple output lines 11.

[0082] It should be noted that in step S1, the high level of the first voltage terminals 100 of the plurality of scan lines 10 is sequentially supplied for a preset time period, and it is not necessary to supply the high level of the plurality of scan lines 10 in the same order. Figure 4 , the total time from the first scan line 10 being passed to the last scan line 10 being passed to the high level is a scan cycle T1, then it is only necessary to pass the high level to all scan lines 10 within one scan cycle T1, and it is not necessary to follow a certain order. 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 passed to the high level 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 passed to the high level in sequence. Of course, in order to simplify the program, it is optional to always pass the high level to each scan line in the same order in each scan cycle T1, for example Figure 4 In the embodiment, a high level is applied to the first scan line 10a, the second scan line 10b and the third scan line 10c in sequence.

[0083] In step S2 , voltage detection is performed on the voltage output terminals 110 of all output lines 11 during the time period when each scan line 10 is at a high level, so as to ensure that no key is missed in the detection.

[0084] It can be understood that the scanning period T1 is short enough. Within the extremely short scanning period, all the scanning lines 10 can be passed to a high level at least once, and the output voltages of all the output lines 11 are detected when any scanning line 10 inputs a high level, so that under normal operation, no matter when the key is pressed by a person's hand, it can be detected that the key is pressed.

[0085] Furthermore, to ensure that the LEDs continuously emit light, the duration of scan cycle T1 is set so that the flickering of the LEDs is not perceptible to the naked eye. It is understood that when a high level is input to a scan line 10, the LEDs on that scan line 10 will illuminate, while the other LEDs will remain silent. Therefore, the LEDs do not emit light continuously, but rather intermittently. When the intermittent period is short enough, the flickering of the LEDs will be imperceptible to the naked eye, thereby ensuring that the LEDs appear to be constantly on.

[0086] Optionally, the interval time between the same light-emitting diode lighting up is no more than 41.6 ms, so that the human eye perceives it as constantly on and cannot detect flickering.

[0087] Optionally, the scanning period T1 is no longer than 41.6 ms, which is beneficial for the light emitting diode to emit continuous light in a sensory sense and ensures that under normal operation, it can be detected that the key is pressed no matter when the key is pressed by a human hand.

[0088] In order to ensure that there is sufficient time to detect the voltage of the output line 11 after the scan line 10 is powered on, in step S1, the time for each high level input of any of the scan lines 10 is not less than 50 microseconds, so that there is sufficient time to detect the output line 11. Further, optionally, the time for each high level input of any of the scan lines 10 is not less than 100 microseconds. As a further improvement, in step S2, the voltage output terminal 110 of the output line 11 is detected after a preset time period after the high level is input to the scan line 10. Generally, the voltage level will fluctuate (lasting about 10 to 30 microseconds) within a period of time after the high level is input to the scan line 10. Therefore, performing voltage detection after a preset time period after the high level is input to the scan line 10 can make the voltage of the voltage output terminal 110 more stable and the detection result more accurate. Optionally, the length of the preset time period is greater than or equal to 30 microseconds, and can further be greater than or equal to 50 microseconds to ensure the accuracy of the detection result and avoid false detection caused by level jitter.

[0089] Optionally, step S3 includes the following steps:

[0090] S31. When the voltage signal at the voltage output terminal 110 of a certain output line 11 is detected to be within a preset amplitude range, the scanning line 10 that is simultaneously receiving a high voltage level is obtained. For ease of description, the output line 11 corresponding to the voltage output terminal 110 for which the voltage signal is detected to be within the preset amplitude range is referred to as a qualified output line 11.

[0091] S32. Identify the key switch connected between the output line 11 that meets the requirements and the scan line 10 that is simultaneously connected to the high level. This key switch is the triggered key switch.

[0092] It is understandable that the position information of each key switch corresponding to the scan line 10 and the output line 11 has been recorded and stored in advance. Therefore, when it is known that the output line 11 detected the voltage and the scan line 10 is connected to the high level at the same time, the position information of the key switch can be obtained, thereby identifying which key switch is triggered. The position information of the key switch corresponds to the position of the pressed key.

[0093] It is understandable that although the intermittent lighting time of the LED is short enough and the frequency is fast enough to appear to be continuously emitting light, the actual lighting time of the LED is relatively short over a period of time. For example, in the case of three scanning lines 10, the LED only emits light for one-third of the time, which will cause the actual observed light brightness to be lower than the light brightness observed when the LED is continuously powered on.

[0094] In order to solve the above-mentioned problem of low brightness, another keyboard backlight circuit driving method is introduced below. For the convenience of description, the above keyboard backlight circuit driving method is called the first keyboard backlight circuit driving method, and the one introduced below is called the second keyboard backlight circuit driving method.

[0095] refer to Figure 5 The second keyboard backlight circuit driving method includes the following steps:

[0096] A1. Drive the light emitting diode to emit light as needed within the first time period t10.

[0097] A2. During the second time period t11, key detection is performed.

[0098] A3. Repeat steps A1 and A2 in sequence.

[0099] In the second keyboard backlight circuit driving method, all LEDs first emit light as needed during a first time period t10, for example, they can be constantly on, or create a breathing or flashing light effect. Then, key detection is performed during a second time period t11, thereby increasing the number of light-emitting modes. Furthermore, while the LEDs continue to emit light during the first time period, the power-on and light-emitting time of the LEDs in the second keyboard backlight circuit driving method is longer than the power-on and light-emitting time of the LEDs in the first keyboard backlight circuit driving method within the same time period (a time period greater than the sum of the first time period t10 and the second time period t11). This results in a higher brightness of light observed by the human eye, further improving the display effect and aesthetics. When the LEDs are used to illuminate the letters on the keys, they can be more easily identified.

[0100] During the first time period t10, a driving voltage signal can be input to the first voltage terminals 100 of all scan lines 10 according to the control signal to drive all light-emitting diodes 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 terminals 100 of all scan lines 10. In this embodiment, the light-emitting diodes continuously emit light during the first time period t10 to maximize the brightness of the light observed by the naked eye. In other embodiments, during the first time period t10, a high level is input to the first voltage terminals 100 of all scan lines 10 according to the control signal. The time and sequence of inputting the high level can be set as needed to make each light-emitting diode emit light as needed, for example, it can emit light in sequence, at intervals, etc., to produce a variety of lighting effects. The light emission of each light-emitting diode can be controlled as needed, for example, by controlling the light-emitting diodes through PWM to produce light effects such as flashing or flowing water.

[0101] The first time period t10 and the second time period t11 constitute a lighting cycle. It is understood that the longer the first time period t10, the longer the LED can continue to emit light when it is continuously powered on, and the brighter the brightness perceived by the naked eye. When the LED produces a lighting effect during this time period, the human eye can reduce the perception of the light emitted during the second time period t11, thereby better ensuring the continuity of the lighting effect change. Optionally, the first time period t10 is greater than the second time period t11, so that the LED can emit light with good brightness and improve the continuity of the lighting effect change. Furthermore, optionally, the first time period t10 and the lighting cycle T2 account for no less than 80% of the time. In this way, the brightness perceived by the naked eye is substantially consistent with the brightness achieved by the LED when it is always powered on, and the continuity of the lighting effect change is also improved. The ratio of the first time period t10 to the lighting cycle T2 can further be selected to be no less than 90%. Furthermore, optionally, the ratio of the first time period t10 to the lighting cycle T2 is no more than 99.9% to prevent inaccurate key detection due to too short a time.

[0102] It can be understood that the light-emitting period T2 needs to be short enough. Within the extremely short light-emitting period T2, all scan lines 10 can be passed to a high level at least once, and the output voltages of all output lines 11 are detected when any scan line 10 is passed to a high level, so that under normal operation, no matter when the key is pressed by the human hand, it can be detected that the key is pressed.

[0103] Optionally, the duration of the light-emitting period T2 is no greater than (or less than or equal to, no more than) 41.6ms, which is conducive to making the light-emitting diode emit continuous light in a sensory sense and ensuring that under normal operation, no matter when the key is pressed by the human hand, it can be detected that the key is pressed.

[0104] Key detection can be implemented in a variety of ways. This specification cites two ways for illustration. The first key detection step in step A2 includes:

[0105] A21. A high level of a preset duration is applied to the first voltage terminals 100 of multiple scan lines 10 in sequence, and a high level is applied to only the first voltage terminal 100 of one scan line 10 at a time, that is, a high level is applied to at most one scan line 10 at a time.

[0106] A22. Detect the voltage signals of the voltage output terminals 110 of the plurality of output lines 11 during the high-level period, and determine whether there is a voltage signal whose voltage is within a preset amplitude range.

[0107] A23. When it is detected that the voltage signal of a certain voltage output terminal 110 is within the preset amplitude value range, the triggered key switch is determined in combination with the voltage conditions of the voltage output terminal 110 of the high-level scan line 10 and multiple output lines 11.

[0108] It can be understood that the key detection step in step A2 is basically the same as the step in the first keyboard backlight circuit driving method, and reference can be made to the relevant content in the first keyboard backlight circuit driving method above.

[0109] The total time from the first scan line 10 being passed to the high level to the last scan line 10 being passed to the high level is a scan cycle T3. It can be understood that in the second keyboard backlight circuit driving method, the second time period t11 is the same as the time period of the scan cycle T3. Of course, it can also be inconsistent. For example, referring to Figure 6 A pause may be provided before and / or after scanning cycle T3, so that second time period t11 is longer than scanning cycle T3. Furthermore, second time period t11 is not limited to including only one scanning cycle T3, but may include multiple scanning cycles to perform more comprehensive detection and improve detection accuracy. Obviously, setting the second time period t11 and N (N is an integer greater than or equal to 1) scanning cycles T3 to have the same length can more effectively utilize time and improve work efficiency.

[0110] Likewise, the duration of the scanning period T3 may be no greater than 41.6 ms.

[0111] Similarly, in step A21, the duration of each high-level input to any of the scan lines 10 is no less than 50 microseconds, and can further be no less than 100 microseconds. In step A22, the voltage output terminal 110 of the output line 11 is tested again after a preset period of time has passed after the high-level input to the scan line 10, so that the voltage at the voltage output terminal 110 is more stable and the test result is more accurate. Optionally, the length of the preset period of time is greater than or equal to 30 microseconds, and can further be greater than or equal to 50 microseconds, to ensure the accuracy of the test result and avoid false detection caused by voltage jitter.

[0112] Similarly, step A23 may include the following steps:

[0113] A231. When the voltage signal of the voltage output terminal 110 of a certain output line 11 is detected to be within a preset amplitude range, a high level scan line 10 is obtained at the same time;

[0114] A232. Identify the push button switch connected between the output line 11 that meets the requirements and the scanning line 10 that is passed to a high level at the same time. The push button switch is the triggered push button switch. The output line 11 that meets the requirements refers to the output line 11 corresponding to the voltage output terminal 110 whose detected voltage signal is within the preset amplitude value range.

[0115] Optionally, in order to allow the human eye to recognize the constantly on light, the second time period t11 is less than or equal to 41.6 ms, so that the human eye cannot recognize the flashing of the light emitting diode during key detection.

[0116] Further optionally, the time of the light-emitting cycle T2 is not greater than (or less than or equal to, not exceeding) 41.6ms, so that the time of the light-emitting cycle T2 is short enough to reliably identify the normal key operation of a person's hand. Optionally, the duration of the second time period t11 is less than or equal to 15ms to further improve the continuity of the light of the light-emitting diode recognized by the human eye, so that the human eye observes a light-emitting diode that is basically always on.

[0117] refer to Figure 7 The second key detection step in step A2 includes:

[0118] A21 'in the second time period t11, according to a preset manner for all scan lines 10 of the first voltage terminal 100 into the driving voltage signal, different scan lines 10 into the driving voltage signal frequency components are different, continuously receiving all output lines 11 of the voltage output terminal 110 of the voltage signal;

[0119] A22 'the received voltage signal of the voltage output terminal 110 is sampled to obtain different frequency component information of the voltage signal of the voltage output terminal 110;

[0120] A23'. Determine the triggered key switch based on the frequency component information of the voltage signal.

[0121] The driving voltage signal can be, for example, a sinusoidal signal, a square wave signal, or other orthogonal signal having a certain frequency. Since the voltage output terminal 110 of the output line 11 can detect the voltage of the corresponding frequency component only when the key switch on the output line 11 is pressed, the pressed key can be determined by the frequency component of the voltage signal at the voltage output terminal 110. In addition, since the triggered key switch is determined by detecting the frequency component of the voltage signal, the driving voltage signal can be applied to multiple (at least two or even all) scanning lines 10 simultaneously without having to apply the driving voltage signals sequentially. When the same output line 11 detects voltage signals containing multiple different frequency components, it indicates that multiple key switches connected to different scanning lines 10 have been pressed.

[0122] Specifically, step A23' may include the following steps:

[0123] A231 'according to the frequency component information of the voltage signal of the output terminal 110 of the output line 11, the drive voltage signal corresponding to the frequency component of the scan line 10 is identified;

[0124] A232 ′. Identify the key switch connected between the output line 11 and the scan line 10 having the same voltage frequency component. The key switch is the triggered key switch.

[0125] It is understandable that the position information corresponding to each key switch and 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 component are known, the position information of the key switch can be obtained, thereby identifying the triggered key switch. The position information of the key switch corresponds to the position of the key.

[0126] For example, reference Figure 1 or Figure 3, driving voltage signals containing frequency components of 1 kHz, 2 kHz, and 3 kHz are applied to the first scan line 10a, the second scan line 10b, and the third scan line 10c, respectively. When the voltage output terminal 110 of the first output line 11a detects the voltage signal containing the 1 kHz frequency component, the key switch SW1 connecting the first output line 11a and the first scan line 10a can be found (indicating that the key switch SW1 is pressed), and the position information corresponding to the key switch can be obtained to determine the pressed key. When the voltage output terminal 110 of the first output line 11a detects the voltage signal containing the 1 kHz, 2 kHz, and 3 kHz frequency components, the key 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 key switches SW1, SW4, and SW7 are all pressed. The position information corresponding to the key switches SW1, SW4, and SW7 can be obtained to determine the pressed key. The key press conditions of the other output lines 11 can be deduced in the same way. For example, when driving voltage signals containing 1 kHz, 2 kHz, and 3 kHz frequency components are respectively supplied 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 1 kHz frequency component, it indicates that the key switch SW1 is pressed. When the voltage output terminal 110 of the first output line 11a detects a voltage signal containing 1 kHz, 2 kHz, and 3 kHz frequency components, it indicates that the key switches SW1, SW4, and SW7 are all pressed. The key press conditions of the other output lines 11 can be deduced in the same way.

[0127] Optionally, in step A21', the difference in center frequency of the driving voltage signal input to the first voltage terminal 100 of each scanning line 10 is not less than one percent of the maximum 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.

[0128] Optionally, in step A22 ′, frequency component information of the voltage signals of different voltage output terminals 110 is obtained by performing Fourier expansion on the sampled voltage signal.

[0129] It is understandable that, since the drive voltage signal can be applied to multiple scan lines 10 simultaneously and the output line 11 is continuously sampled and tested, there is no need to apply the drive voltage signal to the scan lines 10 one by one. Therefore, compared with the method of applying a high level to the scan lines 10 one by one for testing, the time for each scan line 10 to apply the drive voltage signal can be increased, thereby effectively ensuring the detection time and facilitating improved detection accuracy. In addition, the frequency of the voltage is less susceptible to the influence of the external environment (such as static electricity) than the magnitude of the voltage, further improving the accuracy of the detection.

[0130] It is understandable that there are many ways to pass the driving voltage signal to the first voltage terminal 100 of the scan line 10 in a preset manner.

[0131] In some embodiments, the preset method is to continuously apply 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 applied and the output line 11 can be continuously detected, the accuracy of key detection can be greatly improved, timeliness can be guaranteed, and delay can be reduced. The situation where a key operation is not detected due to a time interval between applying the driving voltage signal will not occur, making it more reliable. Furthermore, each scan line 10 continuously has a voltage input during the key detection period. Therefore, each light-emitting diode can still continue to emit light in the second time period t11. In the case where the light-emitting diode needs to continuously emit light, the continuity and brightness of the observed light can be increased.

[0132] In other embodiments, the preset method is to apply a high-level driving voltage to the scanning line 10 according to a preset power-on cycle of each scanning line. The power-on cycles of the scanning lines 10 can be the same or different. The power-on cycle includes a power-on time and a non-power-on time. It can be understood that the voltage signal applied during 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 scanning line 10 can be the same or different. Figure 8 and Figure 9 The power-on periods of the first scanning line 10a, the second scanning line 10b and the third scanning line 10c are T3, T4 and T5 respectively. Figure 8 In the illustrated embodiment, the durations of the power-on periods T3 , T4 and T5 are different, and the power-on time ton and the non-power-on time toff in the power-on period of each scanning line 10 each account for half. Figure 9 In the illustrated embodiment, the durations of the power-on periods T3, T4, and T5 are the same, and the power-on time ton within each power-on period of each scan line 10 is significantly longer than the off-power time toff. This allows the scan lines 10 to be powered for a longer period, which is more conducive to improving the accuracy of key detection and reducing key detection latency. Furthermore, optionally, when driving voltage is applied to the scan lines 10 according to the predetermined power-on period of each scan line, all scan lines 10 or at least two scan lines 10 are simultaneously supplied with the driving voltage signal within a certain period of time.

[0133] Optionally, within a power-on cycle, the power-on time is greater than one-Mth 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 duration of the LEDs, increasing the brightness perceived by the naked eye. Furthermore, optionally, within a power-on cycle, the power-on time is greater than one-half of the power-on cycle to further improve the effect.

[0134] It is understood that the keyboard has a light-emitting unit that can illuminate the keys to achieve backlighting. The light-emitting unit is located below the keys and emits light toward the side where the keys are located. Generally, each key is provided with a corresponding light-emitting unit. The backlight color can be monochrome or multicolored. When the backlight color is monochrome, for example, it can be white, red, green, blue or other colors. In this case, the light-emitting unit can include only one light-emitting diode, which is connected in series. Figure 1 and Figure 3 In the circuit shown, light emission is achieved. When the backlight color is multicolored, a richer color effect can be achieved. For example, the color can gradually change, making the backlight effect more cool. In this case, the light-emitting unit may include at least two light-emitting diodes that emit light of different colors. The different colored light-emitting diodes can emit a single color alone or mix to emit new colors, thereby achieving a richer color.

[0135] The following introduces the keyboard backlight circuit with multi-color lighting effect.

[0136] The keyboard backlight circuit with a multi-color lighting effect has a structure that is essentially the same as the keyboard backlight circuit described above. The difference is that the light-emitting unit of the keyboard backlight circuit with a multi-color lighting effect includes at least two LEDs emitting light of different colors. One of the LEDs is connected in series with a first resistor and allows current to flow unidirectionally toward the first resistor. It emits light under the drive of the signal input to the scan line 10. The other LEDs are controlled by other control circuits and can cooperate with the LED connected in series with the first resistor to produce a variety of lighting effects. For ease of description, the LEDs in the light-emitting unit other than the LED connected in series with the first resistor are referred to as other LEDs.

[0137] In this way, the light emitting diode connected in series with the first resistor and the light emitting diodes of different colors can be used to produce a variety of colors, forming a more diverse lighting effect. Optionally, the light emitting unit includes three light emitting diodes, which respectively emit red, green, and blue light (the three primary colors of light), thereby basically being able to combine and produce any color that is recognizable to the human eye.

[0138] In some embodiments, the color of the light emitted by the light-emitting diode connected in series with the first resistor is red. It is understandable that, since key detection is required, the light-emitting diode connected in series with the first resistor must be at a high level for a certain period of time, which causes the light-emitting diode to emit light during key detection, even if the light-emitting diode does not need to emit light during this time under the preset light 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 light-emitting diode connected in series with the first resistor to red can reduce the light of the light-emitting diode connected in series with the first resistor from attracting the attention of the human eye during key detection, thereby not affecting the keyboard from emitting light in the predetermined light-emitting mode.

[0139] The key input device further includes a control circuit 3 for controlling the light emission of other light emitting diodes. Each of the other light emitting diodes is provided in a control circuit so that each light emitting diode can be independently controlled to emit light. Figure 10 As shown, 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 light-emitting diode (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 pole of the light-emitting diode is close to the third voltage terminal 30, so that the light-emitting diode can emit light when driven by the voltage of the third voltage terminal 30.

[0140] 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 inputs a driving voltage signal to the plurality of scan lines 10 and detects the voltage signal at the voltage output terminal 110 of the output line 11. The chip also inputs a driving voltage signal to the third voltage terminal 30 according to a control instruction to control the light-emitting diode within the control circuit. It will be understood that the number of chips is not limited to one. For example, if the chip's IO interface is insufficient, more chips can be used. Furthermore, the keyboard backlight circuit and the control circuit 3 can share a chip, or they can be provided as separate chips.

[0141] The specific structure of the keyboard backlight circuit can be referred to the above description and will not be repeated here.

[0142] It is understandable that the keyboard backlight circuit driving method of the keyboard backlight circuit with a multi-color luminous effect can use the first keyboard backlight circuit driving method described above, or can use the second keyboard backlight circuit driving method described above. Compared with the first keyboard backlight circuit driving method, the second keyboard backlight circuit driving method can better prevent the human eye from observing the light of the light-emitting diode connected in series with the first resistor during key detection because the time when the scan line 10 is passed into the high level is relatively shorter and the brightness is relatively weaker during key detection. Therefore, during key detection, the light-emitting diode is connected in series with the first resistor. At the same time, the light-emitting effect of the light-emitting unit is not affected within the first time period t10. It is understandable that the second keyboard backlight circuit driving method, combined with the light of the light-emitting diode connected in series with the first resistor being red, which is not sensitive to the human eye, can more effectively prevent the human eye from observing the light of the light-emitting diode during key detection.

[0143] The keyboard backlight circuit driving method of the keyboard backlight circuit with a multi-color luminous 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 same content as the above is not repeated here. The following describes the differences.

[0144] Since the light-emitting unit includes at least two light-emitting diodes, in the above-mentioned step A1, a high-level driving voltage is input to the first voltage end 100 of the scanning line 10 and the third voltage end 30 of the control circuit 3 according to the control signal within the first time period t10 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 a built-in lighting control program of the system, or a corresponding control signal generated according to the control instruction issued by the user. After the chip receives the corresponding control signal, the driving voltage signal is input to the first voltage end 100 and the third voltage end 30 of the scanning line 10 according to the control signal, for example, a high-level driving voltage is passed at a certain time and sequence, so that each light-emitting diode emits light at the required time, thereby achieving diversified lighting effects, for example, all light-emitting diodes can be continuously illuminated to achieve a constantly bright backlight effect, or produce a changing lighting effect.

[0145] During the second time period t11, in some embodiments, other LEDs are controlled to emit light (by supplying a driving voltage signal) based on a control signal to improve the duration and brightness of the light-emitting display effect, thereby overriding the light emitted by the LED connected in series with the first resistor. In other embodiments, the other LEDs may be controlled not to emit light (by not supplying a driving voltage signal). Since the second time period t11 is relatively short, this has a minimal impact on the light-emitting display effect and is more energy-efficient.

[0146] The present invention further provides a key input device, which includes any one of the keyboard backlight circuits described above. The key input device may be, for example, a keyboard, such as a keyboard of a mobile phone or a computer.

[0147] The key input device includes a key circuit board, such as Figure 11 As shown, the key circuit board includes a first circuit board 40 and a second circuit board 41 spaced apart from each other, and a spacer layer 42 connected between 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 any). The second circuit board 41 is provided with a scanning line 10, a light-emitting diode 46 and a first resistor (not shown). Conductive lines (such as silver paste lines) can be set on the first circuit board 40 and the second circuit board 41 to form the scanning line 10 and the output line 11.

[0148] The key switch is connected between the first circuit board 40 and the second circuit board 41. Figure 11 As shown, the key switch includes a first contact 430 located on a first circuit board 40 and electrically connected to the output line 11, and a second contact 431 located on a second circuit board 41 and electrically connected to the scan line 10. The two contacts are spaced apart from each other, and a spacer layer 42 is provided with a cavity 420 through which the first contact 430 and the second contact 431 are exposed. A reset member 44 and a key 45 are correspondingly disposed above the key switch. The reset member 44 can be made of an elastic material such as rubber or silicone. When the key 45 is pressed, it depresses the reset member 44 and the key switch, causing the first contact 430 and the second contact 431 to contact, thereby connecting the scan line 10 and the output line 11. When the key 45 is released, the key 45 is reset by the elastic force of the reset member 44, disconnecting the scan line 10 and the output line 11.

[0149] The light emitting diode 46 is provided on the second circuit board 41, and a avoidance hole 400 is provided on the spacer layer 42 and the first circuit board 40 for exposing the light emitting diode 46. The light emitting diode 46 is provided in the avoidance hole 400, and its light can be emitted toward the key 45. In some embodiments, a light-transmitting area 450 made of a transparent material is provided on the key 45. The light-transmitting area 450 can, for example, be consistent with the letters / graphics marked on the key 45, so that the light of the light emitting diode 46 can illuminate the letters / graphics, which is more beautiful. The key 45 can also be set to be fully transparent. In this case, the part of the key 45 other than the part marked with the letters / graphics forms the light-transmitting area 450 (that is, the light-transmitting area 450 includes the case where the key 45 is partially transparent or fully transparent). In other embodiments, refer to Figure 12The inner surface of the button 45 is provided with a reflective layer 451, and the reflective layer 451 has a reflective surface that reflects the light of the light-emitting diode 46. The area around the button 45 is illuminated by the reflected light, thereby 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 can be directly used as the reflective surface.

[0150] 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 all be arranged on the second circuit board 41 , and of course can also be arranged on the first circuit board 40 .

[0151] Optionally, the first circuit board 40 and the second circuit board 41 are both thin film circuits.

[0152] In the present invention, only two layers of circuit boards are needed to realize 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 made smaller. In this way, the key input device can also be made smaller. For products such as notebooks that have high requirements for lightness and thinness, the thickness of the notebook can be effectively reduced, thereby improving the competitiveness of the product.

[0153] The present invention further provides an electronic device comprising any of the keyboard backlight circuits 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.

[0154] The present invention also provides a processor-readable storage medium for storing processor-executable instructions. When the processor-executable instructions are loaded and executed by the processor, any of the keyboard backlight circuit driving methods described above can be implemented. It is understood that a key input device and / or electronic device can include the processor-readable storage medium.

[0155] It should be noted that, in the absence of conflict, the various embodiments herein can be combined with each other to obtain more implementation plans.

[0156] The above is only a specific embodiment of the present invention, and any other improvements made based on the concept of the present invention are considered to be within the protection scope of the present invention.

Claims

1. A keyboard backlight circuit with integrated key detection function, characterized in that: include: A plurality of scanning lines (10), wherein the plurality of scanning lines (10) are arranged at intervals, wherein the scanning lines (10) have a main line (102) and a plurality of parallel branch lines (103) connected to the main line (102), wherein the main line (102) has a first voltage terminal (100), and the branch line (103) has a second voltage terminal (101), wherein the second voltage terminal (101) is a ground voltage terminal, and a light-emitting unit and a first resistor are sequentially arranged between a connection position between the branch line (103) and the main line (102) and the second voltage terminal (101), wherein the light-emitting unit is used for keyboard backlighting and comprises at least two light-emitting diodes emitting light of different colors, wherein one of the light-emitting diodes is connected in series with a first resistor, and causes current to flow unidirectionally toward the first resistor; and A plurality of output lines (11), wherein the plurality of output lines (11) are arranged at intervals and staggered with the scan lines (10) to form a matrix circuit, wherein the plurality of output lines (11) correspond one-to-one to the plurality of branch lines (103) of the scan lines (10), wherein the output line (11) has a voltage output terminal (110) and a plurality of switch circuits (12) respectively connected to the plurality of branch lines (103) of the scan lines (10), wherein each branch line (103) is provided with a corresponding switch circuit (12), wherein the switch circuit (12) and the branch line (103) connected thereto are connected to a portion located between the light-emitting diode and the first resistor, and wherein the switch circuit (12) includes a key switch.

2. The keyboard backlight circuit with integrated key detection function according to claim 1, characterized in that: The light emitting unit includes three light emitting diodes, which respectively emit red, green and blue light.

3. The keyboard backlight circuit with integrated key detection function as claimed in claim 1, characterized in that: The light emitted by the light emitting diode connected in series with the first resistor is red.

4. The keyboard backlight circuit with integrated key detection function as claimed in claim 1, characterized in that: The light-emitting diodes of the light-emitting unit other than the light-emitting diode connected in series with the first resistor are other light-emitting diodes, and each of the other light-emitting diodes is provided in a control circuit, wherein the control circuit comprises a third resistor, a third voltage terminal (30) for inputting a driving voltage signal, and a fourth voltage terminal (31) for grounding, and the light-emitting diode and the third resistor are sequentially connected in series between the third voltage terminal (30) and the fourth voltage terminal (31).

5. The keyboard backlight circuit with integrated key detection function as claimed in claim 4, characterized in that: The first voltage terminal (100), the third voltage terminal (30) and the voltage output terminal (110) are all connected to the IO interface of the chip, and the chip is capable of inputting driving voltage signals to the plurality of scanning lines (10) and detecting the voltage signal of the voltage output terminal (110) of the output line (11).

6. The keyboard backlight circuit with integrated key detection function according to any one of claims 1 to 5, characterized in that: The switch circuit (12) also includes a second resistor connected in series with the key switch.

7. The keyboard backlight circuit with integrated key detection function as claimed in claim 6, characterized in that: The resistance of the second resistor is greater than that of the first resistor.

8. The keyboard backlight circuit with integrated key detection function as claimed in claim 6, characterized in that: The resistance of the second resistor is greater than or equal to 2 times the resistance of the first resistor and less than or equal to 10 times the resistance of the first resistor.

9. A keyboard backlight circuit driving method, characterized in that: The method is performed by the keyboard backlight circuit with integrated key detection function according to any one of claims 1 to 8, comprising the following steps: A1. Driving the light emitting diode on demand within the first time period t10; A2. During the second time period t11, key detection is performed; A3. Repeat steps A1 and A2 in sequence.

10. The keyboard backlight circuit driving method according to claim 9, wherein: In the step A1, a driving voltage signal is input to the first voltage terminal (100) of the scanning line (10) and the third voltage terminal (30) of the control circuit according to a control signal within a first time period t10, so as to control all light-emitting diodes to emit light according to the control signal.

11. The keyboard backlight circuit driving method according to claim 10, wherein: In the second time period t11, the other light emitting diodes are controlled to emit light or not according to the control signal.

12. The keyboard backlight circuit driving method according to claim 9, wherein: The first time period t10 is greater than or equal to the second time period t11.

13. The keyboard backlight circuit driving method according to claim 12, wherein: The first time period t10 and the second time period t11 constitute a light cycle T2, and the time proportion of the first time period t10 and the light cycle T2 is not less than 80%; the time proportion of the first time period t10 and the light cycle T2 is not greater than 99.9%.

14. The keyboard backlight circuit driving method according to claim 9, wherein: The duration of the second time period t11 is no more than 41.6 ms.

15. The keyboard backlight circuit driving method according to claim 14, wherein: The first time period t10 and the second time period t11 form a lighting cycle T2. The duration of the lighting cycle 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.

16. The keyboard backlight circuit driving method according to any one of claims 9 to 15, wherein: In step A2, performing key detection includes: A21. sequentially applying a high level for a preset duration to the first voltage terminals (100) of the plurality of scanning lines (10), and applying a high level to only the first voltage terminal (100) of one scanning line (10) at a time; A22. Detecting the voltage signals of the voltage output terminals (110) of the plurality of output lines (11) during the high-level period, and determining whether the voltages are within a preset amplitude range; A23. When it is detected that the magnitude of the voltage signal of a certain voltage output terminal (110) is within a preset amplitude value range, the triggered key switch is determined by combining the voltage conditions of the voltage output terminals (110) of the high-level scanning line (10) and the plurality of output lines (11).

17. The keyboard backlight circuit driving method according to claim 16, wherein: The time for each high level input to any of the scan lines (10) is not shorter than 50 microseconds.

18. The keyboard backlight circuit driving method according to claim 17, wherein: In the step A22, the voltage output end (110) of the output line (11) is detected after a preset time period after the scanning line (10) is supplied with a high level, and the preset time period is greater than or equal to 30 microseconds.

19. The keyboard backlight circuit driving method according to claim 17, wherein: The step A23 includes the following steps: A231. When it is detected that the voltage signal of the voltage output terminal (110) of a certain output line (11) is within a preset amplitude value range, obtaining a scanning line (10) that is simultaneously supplied with a high level; A232. Identify a key switch connected between a desired output line (11) and a scanning line (10) that is simultaneously fed with a high level, the key switch being the triggered key switch, wherein the desired output line (11) refers to an output line (11) corresponding to a voltage output terminal (110) whose detected voltage signal is within a preset amplitude range.

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