Keyboard backlight circuit integrated with key detection function and driving method thereof

Abstract

The invention discloses a keyboard backlight circuit integrated with a key detection function and a keyboard backlight circuit driving method.The keyboard backlight circuit integrated with the key detection function comprises a plurality of scanning lines and a plurality of output lines, and the scanning lines are arranged at intervals; a light-emitting unit and a first resistor are sequentially arranged between the first voltage end and the second voltage end of the scanning line, the light-emitting unit is used for keyboard backlight and comprises at least two light-emitting diodes emitting light of different colors, and one light-emitting diode is connected with the first resistor in series and enables current to be conducted towards the first resistor in a one-way mode; the plurality of output lines are arranged at intervals, each output line is provided with a voltage output end and a plurality of switching circuits connected with the plurality of scanning lines respectively, the switching circuits are connected with the parts, located between the light emitting diodes and the first resistors, of the scanning lines connected with the switching circuits, and each switching circuit comprises a key switch. According to the keyboard backlight circuit integrated with the key detection function, the color backlight effect and key detection of the keyboard can be achieved.

Description

Technical Field

[0001] The 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 are becoming more and more diversified. In order to achieve human-computer interaction, electronic devices are usually provided with buttons. For example, computers are often equipped with keyboards for typing, gaming and other operations.

[0003] In order to make the keyboard easy to use in a dark or dim environment, some keyboards have a backlight function, which illuminates the keys or the area around the keys through LEDs (light emitting diodes), so that users can identify the positions of the keys on the keyboard and can accurately perform key operations. The backlight function of the keyboard is realized by the backlight circuit of the keyboard. The backlight circuit is provided with light emitting diodes corresponding to the key positions, and the backlight function of the keyboard is realized by controlling the light emitting diodes to emit light.

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

[0005] That is to say, for a keyboard with a backlight function, it is necessary to set up a keyboard backlight circuit and a key detection circuit at the same time, which leads to a complex circuit layout, a large number of circuit board layers or the need to stack multiple circuit boards, and a large thickness, which ultimately leads to a thick keyboard and a high cost. For a keyboard with a color backlight effect, the layout of the circuit board will be more complicated, 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 and unable to meet the requirements of thinness and lightness of laptops.

[0007] The above contents are only used to help understand the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0008] The object 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 realizing the color backlight effect of the keyboard.

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

[0010] A plurality of scanning lines, the plurality of scanning lines are arranged at intervals, the scanning lines have a main line and a plurality of branch lines connected to the main line in parallel, the main line has a first voltage end, the branch line has a second voltage end, a light-emitting unit and a first resistor are sequentially arranged between the connection position between the branch line and the main line and the second voltage end, the light-emitting unit is used for keyboard backlight, and comprises at least two light-emitting diodes emitting light of different colors, one of the light-emitting diodes is connected in series with the first resistor, and makes the current unidirectionally conduct 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 and the branch line connected thereto are connected to a portion located between the light-emitting diode and the first resistor, and 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 the plurality of scanning lines and detect the voltage signal at the voltage output terminal of the output line; the second voltage terminal is a ground voltage terminal.

[0016] Furthermore, the switch circuit also 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 proposes a keyboard backlight circuit driving method, which is performed by the keyboard backlight circuit with integrated key detection function as described above, and comprises the following steps:

[0020] A1. Driving the light emitting diode to emit light as needed in the first time period t10;

[0021] A2. Perform key detection in the second time period t11;

[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 end of the scanning line and the third voltage end of the control circuit according to a control signal within a first time period t10, so as to control all the light emitting diodes to emit light according to the control signal.

[0024] Further, in the second time period t11, other light emitting diodes are controlled to emit light or not emit light 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 time proportion of the first time period t10 and the light-emitting cycle T2 is not less than 80%; the time proportion of the first time period t10 and the light-emitting cycle T2 is not greater than 99.9%.

[0027] Furthermore, the duration of the second time period t11 is no more than 41.6 ms.

[0028] Furthermore, the first time period t10 and the second time period t11 form a light-emitting cycle T2, the time length of the light-emitting cycle T2 is less than or equal to 41.6 ms, and the time length 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 time to the first voltage terminals of the plurality of scan lines, and pass a high level to only one first voltage terminal of the scan line at the same time;

[0031] A22. Detecting the voltage signals at the voltage output terminals of the plurality of output lines during the high level period, and determining whether there is a voltage signal whose voltage is within the range of a preset amplitude value;

[0032] A23. When it is detected that the voltage signal at 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 voltage output terminals of the scanning line passing a high level and the plurality of 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 passed to the scan line, and the preset time period is greater than or equal to 30 microseconds.

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

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

[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 terminal 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, the light-emitting unit includes at least two light-emitting diodes emitting light of different colors, which can achieve a color 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, and in addition, a 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, so that the keyboard backlight circuit integrates the key detection function, simplifies the circuit structure, and is conducive to reducing the thickness of a 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 of preventing false detection.

[0041] Figure 3 This is a circuit diagram of a keyboard backlight circuit with 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 passing a high level to each scanning line during key detection in an embodiment of the present invention, and two scanning cycles are shown in the figure.

[0043] Figure 5 It is a timing diagram of a light-emitting cycle of an embodiment of the present invention.

[0044] Figure 6 It is a timing diagram of a light-emitting cycle of an embodiment of the present invention.

[0045] Figure 7 It is a timing diagram of a light-emitting cycle of an embodiment of the present invention.

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

[0047] Fig. 9 It is a timing diagram of the power-on period of each scanning line in an embodiment of the present invention.

[0048] Fig.10 It is a circuit diagram of a control circuit in one embodiment of the present invention.

[0049] Fig.11 It is a structural schematic diagram of a key input device in an embodiment of the present invention.

[0050] Fig.12 It is a structural schematic diagram of a key input device in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, 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 is to 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 structures related to the present application are shown in the accompanying drawings, rather than all structures. 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] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0053] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood 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 integrated key detection function (hereinafter referred to as 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, a 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 arranged in an interlaced manner 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, that is, "plurality" means two or more, therefore, in other embodiments, the number of the scan lines 10 and the output lines 11 may be two or more than three. It should be further noted that, although in the illustrated embodiment, the number of the scan lines 10 and the output lines 11 are the same, this is not necessarily the case, and the numbers of the two may be different, for example, one of them is two and the other is three, and so on.

[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 scanning 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, and 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 diode allows the current to be unidirectionally conducted toward the second voltage terminal 101, that is, the current introduced into the first voltage terminal 100 flows into the positive electrode of the light emitting diode, then flows out from the negative electrode of the light emitting diode, and flows through the first resistor, so that the light emitting diode emits light. It can be understood that due to the unidirectional conduction characteristic of the light emitting diode, the current cannot flow from the negative electrode to the positive electrode.

[0058] The output line 11 has a voltage output terminal 110 and a plurality of switch circuits 12 respectively connected to the plurality of scan lines 10. Specifically, the plurality of switch circuits 12 are respectively connected to the branch lines 103 of the plurality of scan lines 10. More specifically, the switch circuit 12 is connected to the portion of the branch line 103 between the light emitting diode and the first resistor. The plurality of switch circuits 12 of the same output line 11 are connected in parallel. Each branch line 103 is correspondingly provided with a switch circuit 12. The switch circuit 12 includes a key switch, Figure 1 SW1 to SW9 marked in are push switches, which correspond to the position of the key (usually located below the key). When the key is pressed, the key will move downward to trigger the key switch to close, making the switch circuit 12 conductive. Conversely, when the key switch is released, the key is reset, making the key switch disconnected.

[0059] The first voltage terminal 100 of the scan 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 scan line 100, the light-emitting diode is driven to emit light. The light-emitting diode can illuminate the key, thereby playing the role of 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 displaying the letter can be set to be 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 the first voltage terminal 100 of the scan line 10 (for example, the first scan line 10a) connected thereto is applied with a high-level driving voltage, 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 there is a pressed key switch.

[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 may be greater than 0V, that is, as long as a voltage of a certain magnitude is detected, it is considered that the key is pressed.

[0062] In some embodiments, in order to reduce the 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 size. The voltage value obtained by calculation or actual measurement can be used as a basis for judging whether there is a voltage in the preset range at the voltage output terminal 110. 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 magnitude 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 with a voltage magnitude greater than or equal to a fixed value. The voltage signal may be smaller than a certain amplitude of a calculated or measured voltage value, or may be equal to a 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 to achieve 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, and 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 switch SW1 and the key switch SW2 are pressed at the same time. Similarly, the position of the pressed key can be determined by combining the voltage conditions of the voltage output terminals 110 of the scan line 10 and the plurality of output lines 11 to which a high level is applied, thereby realizing key detection.

[0065] Since the light emitting diode is connected in series in the scanning line 10, the unidirectional conduction characteristic of the light emitting diode can be used to achieve the effect of anti-ghosting. For example, when the current is passed through the second scanning line 10b (i.e., the high-level driving voltage is passed through), and the key switches SW1, SW2 and SW4 are pressed at the same time, at this time, only the voltage output end of the first output line 11a can detect the voltage within the preset amplitude value range. Due to the unidirectional conduction effect of the light emitting diode D1, the current cannot pass through 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 being pressed. Therefore, the above-mentioned keyboard backlight circuit can prevent false detection.

[0066] It is understandable that, through the above circuit structure design, while achieving the light-emitting effect of the key, it can also play an anti-ghosting function, thereby simplifying the circuit structure and helping to reduce costs. At the same time, the simplified circuit structure can reduce the number of layers of the circuit board of the key output device, thereby helping to reduce the thickness of the key input device and achieve lightweight electronic equipment.

[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 driving voltage signals to multiple scanning lines according to control signals, 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 about 5V. By setting the resistance of the first resistor to 100-1000 ohms, the current flowing through the light-emitting diode can be 1-10mA, which meets the current required for most light-emitting diodes used in keyboards to emit light. In other embodiments, the driving voltage input to the first voltage terminal 100 is about 3.3V. At this time, the resistance of the first resistor can be selected to be 30-500 ohms so that the light-emitting diode can emit light reliably.

[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, Figure 3 As shown, the switch circuit 12 also includes a second resistor connected in series with the key switch. Figure 3 R10 to R18 are the second resistors, and the resistance of the second resistor 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, and the resistance after the parallel connection is smaller than the resistance of the single first resistor, 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 at the same time. When the resistance values ​​of the first resistors R1 and R4 are the same, the resistance value 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 the 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 of the same output line 10 are pressed simultaneously, due to the presence of the second resistor, the resistance of the resistor that is finally divided with the light emitting diode will decrease relatively smaller, thereby ensuring the stability of the current flowing through the light emitting diode when the key is pressed, reducing the increase in the current, which is conducive to the reliable light emission of the light emitting diode, and the light emission effect is more consistent and stable, and it is also conducive to extending its service life. For example, when the first voltage terminal 100 of the first scanning line 10a inputs a high level 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 resistance after parallel connection will be greater than the resistance after only R1 and R4 are connected in parallel, reducing the increase in the current flowing through the light emitting diode.

[0073] In order to further ensure the stability of the light emitting diode, the resistance of the second resistor can be greater than or equal to 1 times, 2 times, 3 times, 4 times, 5 times 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 amplitude of the current flowing through the light emitting diode is smaller, and no obvious optical and electrical effects are caused on the light emitting diode, thereby effectively ensuring the stability of the light emitting diode and the reliability of 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 10 times less than the resistance of the first resistor is beneficial to improving the accuracy of the detection value.

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

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

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

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

[0079] S1. A high level of a preset duration is applied to the first voltage terminals 100 of the plurality of scan lines 10 in sequence, and a high level is applied to only one first voltage terminal 100 of the 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 multiple output lines 11 during the time period when the high level is applied, and determine whether there is a voltage signal whose voltage magnitude is within the 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 scanning line 10 and the multiple output lines 11.

[0082] It should be noted that in step S1, the high level of the preset duration is sequentially applied to the first voltage terminals 100 of the plurality of scan lines 10, and it is not necessary to apply the high level to 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 high level 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 a scan cycle T1, and it is not necessary to follow a certain order. For example, the first scan cycle T1 can pass the high level to the first scan line 10a, the second scan line 10b and the third scan line 10c in turn, and the second scan cycle can pass the high level to the first scan line 10a, the third scan line 10c and the second scan line 10b in turn. Of course, in order to simplify the program, it is optional that each scan cycle T1 always passes the high level to each scan line in the same order, 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, during the time period when each scanning line 10 is at a high level, voltage detection is performed on the voltage output terminals 110 of all output lines 11 to ensure that no key is missed in the detection.

[0084] It can be understood that the scanning period T1 is short enough that all the scanning lines 10 can be passed to a high level at least once within the extremely short scanning period, 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 a key is pressed by hand, it can be detected that the key is pressed.

[0085] Furthermore, in order to ensure that the light-emitting diode can continuously emit light, the time of the scanning cycle T1 is set so that the naked eye cannot recognize the flickering of the light-emitting diode. It can be understood that when a certain scanning line 10 inputs a high level, the light-emitting diode on the scanning line 10 will emit light, while other light-emitting diodes will not emit light. Therefore, the light-emitting diode does not emit light continuously, but emits light intermittently. When the intermittent time is short enough, the flickering of the light-emitting diode will not be detected by the naked eye, thereby ensuring that the light-emitting diode can be displayed as always on in external performance.

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

[0087] Optionally, the scanning cycle T1 is no longer than 41.6 ms, which helps the light emitting diode to emit continuous light to the senses and ensures that under normal operation, it can be detected that the key is pressed no matter when the key is pressed by hand.

[0088] In order to allow enough time to detect the voltage of the output line 11 after the scan line 10 is powered on, in the step S1, the time for any of the scan lines 10 to input a high level each time is not less than 50 microseconds, so that there is enough time to detect the output line 11. Further, optionally, the time for any of the scan lines 10 to input a high level each time is not less than 100 microseconds. As a further improvement, in the step S2, the voltage output terminal 110 of the output line 11 is detected after a preset time period after the scan line 10 is fed with a high level. Generally, within a period of time after the scan line 10 is fed with a high level, the level will jitter (lasting about 10 to 30 microseconds). Therefore, the voltage output terminal 110 is detected after a preset time period after the scan line 10 is fed with a high level, which can make the voltage 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 be further selected to be greater than or equal to 50 microseconds, so as 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 it is detected that the voltage signal of the voltage output terminal 110 of a certain output line 11 is within the preset amplitude value range, the scanning line 10 that is passed through the high level at the same time is obtained. For the convenience of description, the output line 11 corresponding to the voltage output terminal 110 whose voltage signal is within the preset amplitude value range is called the output line 11 that meets the requirements;

[0091] S32. Identify the key switch connected between the output line 11 that meets the requirements and the scan line 10 that is at a high level at the same time. The key switch is the triggered key switch.

[0092] It can be understood 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 that detects the voltage and the scan line 10 that passes the high level at the same time are detected, 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 shorter 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 next. 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 next is called the second keyboard backlight circuit driving method.

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

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

[0097] A2. In 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 the light-emitting diodes first emit light as needed in the first time period t10, for example, they can be always on, or form a breathing or flashing light effect, and then the key detection is performed in the second time period t11, which increases the light-emitting mode. At the same time, when the light-emitting diodes continue to emit light in the first preset time period, in the same time period (a time period greater than the sum of the first time period t10 and the second time period t11), the power-on and light-emitting time of the light-emitting diodes in the second keyboard backlight circuit driving method is longer than the power-on and light-emitting time of the light-emitting diodes in the first keyboard backlight circuit driving method, so that the light brightness observed by the human eye is higher, which is conducive to further improving the display effect and aesthetics. When the light-emitting diodes are used to illuminate the letters on the keys, they can be more easily identified.

[0100] In 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 generating a light effect. In some embodiments, in 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 in the first preset time period t10 to maximize the light brightness observed by the naked eye. In other embodiments, in 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, so that each light emitting diode emits light as needed, for example, it can emit light in sequence, emit light at intervals, etc., to generate a variety of light effects, and each light emitting diode is controlled to emit light as needed, for example, the light emitting diode is controlled by PWM to generate light effects such as flashing or flowing water.

[0101] The first time period t10 and the second time period t11 form a light-emitting cycle. It can be understood that the longer the first time period t10 is, when the light-emitting diode continues to emit light in this time period, the longer the light-emitting diode can be powered on to continuously emit light, and the brighter the brightness recognized by the naked eye. When the light-emitting diode produces a light effect in this time period, the recognition of the light emission of the second time period t11 by the human eye can be reduced, and the continuity of the light effect change can be better guaranteed. Optionally, the first time period t10 is greater than the second time period t11, so that the light-emitting diode can emit light with good brightness and improve the continuity of the light effect change. Further optionally, the time ratio of the first time period t10 to the light-emitting cycle T2 is not less than 80%, so that the brightness perceived by the naked eye is basically consistent with the brightness achieved by the light-emitting diode when it is always powered on, and the continuity of the light effect change is better. The time ratio of the first time period t10 to the light-emitting cycle T2 can be further selected to be not less than 90%. Further optionally, the time ratio of the first time period t10 to the light-emitting cycle T2 is not greater than 99.9%, so as to prevent the key detection time from being too short, resulting in inaccurate detection.

[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 a person presses the key, it can be detected that the key is pressed.

[0103] Optionally, the duration of the light-emitting cycle T2 is no greater than (or less than or equal to, no greater than) 41.6 ms, 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 a person's hand, it can be detected that the key is pressed.

[0104] The 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 the plurality of scan lines 10 in sequence, and a high level is applied to 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.

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

[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 scanning 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 may be made to the relevant content in the first keyboard backlight circuit driving method above.

[0109] The total time from the first scanning line 10 being passed to the high level to the last scanning line 10 being passed to the high level is a scanning cycle T3. It can be understood that in the second keyboard backlight circuit driving method, the length of the second time period t11 is consistent with the time period of the scanning cycle T3. Of course, it can also be inconsistent, for example, refer to Figure 6 , there may be a pause before and / or after the scanning cycle T3, so that the second time period t11 is greater than the scanning cycle T3. In addition, the second time period t11 is not limited to only one scanning cycle T3, and it may include more scanning cycles to perform more comprehensive detection and improve the accuracy of detection. Obviously, setting the second time period t11 and the time periods of N (N is an integer greater than or equal to 1) scanning cycles T3 to have the same time length can make more full use of time and improve work efficiency.

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

[0111] Similarly, in step A21, the time for any of the scan lines 10 to input a high level each time is not shorter than 50 microseconds, and can be further selected to be not shorter than 100 microseconds. In step A22, the voltage output terminal 110 of the output line 11 is detected after a preset time period after the scan line 10 is passed through a high level, so that the voltage of the voltage output terminal 110 is more stable and the detection result is more accurate. Optionally, the length of the preset time period is greater than or equal to 30 microseconds, and can be further selected to be greater than or equal to 50 microseconds, so as to ensure the accuracy of the detection result and avoid false detection caused by level 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 the preset amplitude value range, the scanning line 10 which is passed to the high level at the same time is obtained;

[0114] A232. Identify the key switch connected between the output line 11 detected to meet the requirements and the scanning line 10 that is passed to a high level at the same time. The key switch is the triggered key 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 human eyes to recognize the constantly on light, the duration of the second time period t11 is less than or equal to 41.6 ms, so that during key detection, human eyes cannot recognize the flashing of the light emitting diode.

[0116] Further optionally, the duration of the light-emitting cycle T2 is not greater than (or less than or equal to, not exceeding) 41.6ms, so that the duration 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, the first voltage terminal 100 of all scan lines 10 is passed into the driving voltage signal, the frequency components of the driving voltage signal of different scan lines 10 are different, and the voltage signal of the voltage output terminal 110 of all output lines 11 is continuously received;

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

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

[0121] The driving voltage signal may be, for example, a sinusoidal signal or a square wave signal or other orthogonal signal with 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, it is possible to determine which key is pressed 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, multiple (at least two or even all) scanning lines 10 can be simultaneously fed with the driving voltage signal without sequentially feeding the driving voltage signal. 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 are pressed.

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

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

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

[0125] It can be understood 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, and the position information of the key switch corresponds to the position of the key.

[0126] For example, refer to Figure 1 or Figure 3, driving voltage signals containing frequency components of 1KHz, 2KHz and 3KHz are respectively passed 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 the voltage signal containing the frequency component of 1KHz, 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 is obtained to determine the pressed key. When the voltage output terminal 110 of the first output line 11a detects the voltage signal containing the frequency components of 1KHz, 2KHz and 3KHz, 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, and 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 other output lines 11 can be deduced in the same way. For example, when driving voltage signals containing 1KHz, 2KHz and 3KHz frequency components are respectively passed to the first scanning line 10a, the second scanning line 10b and the third scanning line 10c, when the voltage output terminal 110 of the first output line 11a detects the voltage signal containing the 1KHz frequency component, it indicates that the key switch SW1 is pressed, and when the voltage output terminal 110 of the first output line 11a detects the voltage signal containing the 1KHz, 2KHz and 3KHz frequency components, it indicates that the key switches SW1, SW4 and SW7 are all pressed, and the key press conditions of 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 voltage signals at different voltage output terminals 110 is obtained by performing Fourier expansion on the sampled voltage signal.

[0129] It is understandable that, since the driving voltage signal can be applied to multiple scanning lines 10 at the same time, and the output line 11 is continuously sampled and detected, it is not necessary to apply the driving voltage signal to the scanning lines 10 in sequence. Therefore, compared with the method of applying a high level to the scanning lines 10 in sequence for detection, the time for each scanning line 10 to apply the driving voltage signal can be increased, thereby effectively ensuring the detection time, which is conducive to improving the accuracy of the detection. 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, which further improves 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 pass the driving voltage signal to the first voltage end 100 of all the scanning lines 10. In this embodiment, since the driving voltage signal can be continuously passed 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 the key operation is not detected due to the time interval of passing the driving voltage signal will not occur, which is more reliable. Furthermore, each scanning line 10 has a continuous voltage input during the key detection period, so each light-emitting diode can still continue to emit light in the second time period t11. When the light-emitting diode needs to continue to 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 the preset power-on cycle of each scanning line. The power-on cycles of each scanning line 10 may be the same or different, and 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, and the power-on time included in the power-on cycle corresponding to each scanning line 10 may be the same or different. Figure 8 and Fig. 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. Fig. 9 In the illustrated embodiment, the duration of the power-on cycles T3, T4, and T5 is the same, and the power-on time ton in the power-on cycle of each scanning line 10 is much longer than the non-power-on time toff, so that the scanning line 10 is powered for a longer time, which is more conducive to improving the accuracy of key detection and reducing the delay of key detection. Further optionally, when the driving voltage is applied to the scanning line 10 according to the preset power-on cycle of each scanning line, within a certain period of time, all scanning lines 10 or at least two scanning lines 10 are simultaneously supplied with the driving voltage signal.

[0133] Optionally, in one 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 of the keyboard backlight circuit. On the one hand, the power-on time can be increased to ensure the accuracy of detection, and on the other hand, the light-emitting time of the light-emitting diode can be increased to increase the brightness perceived by the naked eye. Further, optionally, in one 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 colorful. When the backlight color is monochrome, for example, it can be white, red, green, blue or other colors. At this time, 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 realized. When the backlight color is colorful, richer color effects can be achieved, for example, the color can change gradually, making the backlight effect more cool. At this time, the light-emitting unit can include at least two light-emitting diodes that emit light of different colors. The light-emitting diodes of different colors can emit one color alone, or they can be mixed to emit new colors, thereby making the colors richer.

[0135] The following is an introduction to the keyboard backlight circuit with multi-color luminous effect.

[0136] The keyboard backlight circuit with multi-color luminous effect has a structure basically consistent with the keyboard backlight circuit described above, except that the luminous unit of the keyboard backlight circuit with multi-color luminous effect includes at least two light-emitting diodes with different luminous colors, one of which is connected in series with the first resistor, and allows the current to be unidirectionally conducted toward the first resistor, and emits light under the drive of the signal passed into the scan line 10, and the other light-emitting diodes are controlled by other control circuits to emit light, and can cooperate with the light-emitting diode connected in series with the first resistor to produce various luminous effects. For the convenience of description, the light-emitting diodes of the luminous unit other than the light-emitting diode connected in series with the first resistor are referred to as other light-emitting diodes.

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

[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 passed into 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 at this time under the preset light control mode. Since the human eye is less sensitive to red light than other colors (blue and green), therefore, 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 during key detection from attracting the attention of the human eye, thereby not affecting the keyboard to emit light in a 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 arranged in a control circuit so that each light emitting diode can be independently controlled to emit light. Fig.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 in sequence. 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 under the voltage drive 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 IO interface of the chip. The chip inputs a driving voltage signal to the plurality of scanning lines 10 and detects the voltage signal of the voltage output terminal 110 of the output line 11. The chip simultaneously inputs a driving voltage signal to the third voltage terminal 30 according to the control instruction to control the light emitting diode in the control circuit to emit light. It is understandable that the number of chips is not limited to one. For example, when the number of IO interfaces of the chip is insufficient, more chips can be used. In addition, the keyboard backlight circuit and the control circuit 3 can share a chip, or they can be provided with independent chips respectively.

[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. At the same time, in the first time period t10, the luminous effect of the light-emitting unit is not affected. 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 is 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 multi-color luminous effect can directly apply the second keyboard backlight circuit driving method mentioned above, including the first key detection step and the second key detection step, and the same contents as above are not repeated. The following introduces the parts with 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 terminal 100 of the scanning line 10 and the third voltage terminal 30 of the control circuit 3 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. 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 a control instruction issued by the user. After the chip receives the corresponding control signal, a driving voltage signal is input to the first voltage terminal 100 and the third voltage terminal 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 a variety of lighting effects, for example, all light-emitting diodes can be made to emit light continuously to achieve a constantly bright backlight effect, or produce a changing lighting effect.

[0145] In the second time period t11, in some embodiments, other light-emitting diodes are controlled to emit light (drive voltage signals are input) according to the control signal to improve the continuity and brightness of the light-emitting display effect, covering the light emitted by the light-emitting diodes connected in series with the first resistor. In other embodiments, other light-emitting diodes can also be controlled not to emit light (drive voltage signals are not input). Since the second time period t11 is relatively short, it has less 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 Fig.11 As shown, the key circuit board includes a first circuit board 40 and a second circuit board 41 which are 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 arranged 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. Fig.11 As shown, the key 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 arranged with a relative spacing, and the spacing layer 42 is provided with a cavity 420 for exposing the first contact 430 and the second contact 431. A reset member 44 and a key 45 are correspondingly arranged above the key switch. The reset member 44 can be made of elastic materials such as rubber or silicone. When the key 45 is pressed, the key 45 presses the reset member 44 and the key switch, so that the first contact 430 and the second contact 431 are in contact, and the scan line 10 and the output line 11 are connected. When the key 45 is released, the key 45 is reset under the elastic force of the reset member 44, and the scan line 10 and the output line 11 are disconnected.

[0149] The light emitting diode 46 is arranged on the second circuit board 41, and a avoidance hole 400 for exposing the light emitting diode 46 is opened on the spacer layer 42 and the first circuit board 40. The light emitting diode 46 is arranged 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 transparent material is provided on the key 45. The light-transmitting area 450 can 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 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 Fig.12A reflective layer 451 is provided on the inner surface of the key 45. The reflective layer 451 has a reflective surface that reflects the light of the light-emitting diode 46. The area around the key 45 is illuminated by the reflected light to improve the aesthetics. In other embodiments, if the inner surface of the key 45 itself has a good reflective effect, the reflective layer 451 may not be provided, and the inner surface of the key 45 can be directly used as the reflective surface.

[0150] It is understandable that when the light-emitting unit includes a plurality of light-emitting diodes, the other diodes and the corresponding control circuit and the third resistor can 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 also provides an electronic device, which includes any of the keyboard backlight circuits described above or includes 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 proposes a processor-readable storage medium, which is used to store 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 can be understood that the 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 in this document can be combined with each other to obtain more implementation plans.

[0156] The above are only specific embodiments 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 branch lines (103) connected in parallel to the main line (102), wherein the main line (102) has a first voltage end (100), and the branch lines (103) have a second voltage end (101), and a light-emitting unit and a first resistor are sequentially arranged between a connection position between the branch lines (103) and the main line (102) and the second voltage end (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 the first resistor, and current is unidirectionally conducted toward the first resistor; and, A plurality of output lines (11), the plurality of output lines (11) are arranged at intervals and are arranged in an alternating manner with the scanning lines (10) to form a matrix circuit, the output lines (11) having a voltage output terminal (110) and a plurality of switch circuits (12) respectively connected to the branch lines (103) of the plurality of scanning lines (10), each branch line (103) being provided with a corresponding switch circuit (12), the switch circuit (12) being connected to a portion of the branch line (103) connected thereto located between the light emitting diode and the first resistor, and the switch circuit (12) comprising a key switch.

2. The keyboard backlight circuit with integrated key detection function as claimed in claim 1, characterized in that: The light emitting unit comprises three light emitting diodes, and the three light emitting diodes emit red, green and blue light respectively.

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, each of the other light-emitting diodes is arranged in a control circuit, 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, the light-emitting diode and the third resistor are connected in series between the third voltage terminal (30) and the fourth voltage terminal (31) in sequence.

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; 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); the second voltage terminal (101) is a ground voltage terminal.

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 value of the second resistor is greater than or equal to 2 times the resistance value of the first resistor, and less than or equal to 10 times the resistance value 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 as claimed in any one of claims 1 to 8, comprising the following steps: A1. Driving the light emitting diode to emit light as needed in the first time period t10; A2. Perform key detection in the second time period t11; A3. Repeat steps A1 and A2 in sequence.

10. The keyboard backlight circuit driving method according to claim 9, characterized in that: In the step A1, a driving voltage signal is input to the first voltage end (100) of the scanning line (10) and the third voltage end (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, characterized in that: In the second time period t11, other light emitting diodes are controlled to emit light or not emit light according to the control signal.

12. The keyboard backlight circuit driving method according to claim 9, characterized in that: 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, characterized in that: The time proportion of the first time period t10 and the light-emitting period T2 is not less than 80%; the time proportion of the first time period t10 and the light-emitting period T2 is not greater than 99.9%.

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

15. The keyboard backlight circuit driving method according to claim 14, characterized in that: The first time period t10 and the second time period t11 form a light-emitting cycle T2, the time length of the light-emitting cycle T2 is less than or equal to 41.6 ms, and the time length 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, characterized in that: In the step A2, key detection includes: A21. sequentially passing a high level for a preset time length to the first voltage ends (100) of the plurality of scanning lines (10), and passing a high level to only the first voltage end (100) of one scanning line (10) at the same 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 voltage is within a preset amplitude range; A23. When it is detected that 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 scanning line (10) passing a high level 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 scanning 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 comprises the following steps: 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 value range, a scanning line (10) having a high level at the same time is obtained; A232. Identify a key switch connected between an output line (11) that meets the requirements and a scanning line (10) that is simultaneously supplied with a high level. The key switch is the triggered key 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 a preset amplitude range.

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