Light source control circuit and projector

Abstract

The invention discloses a light source control circuit and a projector, and relates to the technical field of projection. In the light source control circuit, the input end of a logic processing circuit is connected with a modulation controller, and the output end of the logic processing circuit is used for determining a fluorescent light lightening period according to a lightening / closing signal for controlling blue laser and a lightening / closing signal for controlling green light output by the modulation controller; the input end of the selection switch control circuit is connected with the output end of the logic processing circuit and the output end of the modulation controller, and the output end of the selection switch control circuit is connected with the blue laser driving control circuit and used for outputting a fluorescent light lightening time period signal or controlling a lightening / closing signal of blue laser. Separate control of blue laser as exciting light and emergent light is realized; the input end of the voltage division circuit is connected with the output end of the logic processing circuit, the output end of the voltage division circuit is connected with the input end of the blue laser driving control circuit, and the fluorescent light proportion is adjusted by controlling the current of the blue laser driving control circuit in the fluorescent light lightening period.

Description

Technical Field

[0001] This invention relates to the field of projection technology, and in particular to a light source control circuit and a projector. Background Technology

[0002] In the field of smart micro-projectors, lighting sources have gradually transitioned from mercury lamps and light-emitting diodes (LEDs) to laser light sources. Previously, because red and green laser devices were very expensive, blue lasers were mostly used to excite fluorescence by irradiating phosphors, and then the red and green colors were filtered out by filters.

[0003] In related control technologies, blue laser light is controlled together as both the output light and the excitation light, which fails to meet users' needs for separate control of the blue laser or its sole excitation light. For example, in mixed-light projection, the fluorescence excited by the blue laser mixes with the green light. The proportion of fluorescence affects the green color point; otherwise, it will affect the color gamut and color points of the projected image. Therefore, in this scenario, it is necessary to control the blue laser as the excitation light separately.

[0004] Therefore, how to separately control blue laser as the output light and blue laser as the excitation light to meet the actual needs of users is a technical problem that urgently needs to be solved by those in the field. Summary of the Invention

[0005] The purpose of this invention is to provide a light source control circuit and a projector to solve the technical problem that when blue laser light is controlled together as both the output light and the excitation light, it is impossible to meet the user's need to control the blue laser separately or to control the blue laser separately as the excitation light.

[0006] To solve the above-mentioned technical problems, the present invention provides a light source control circuit, comprising: a laser drive control circuit, a modulation controller, a logic processing circuit, a selection switch control circuit, and a voltage divider circuit; wherein the laser drive control circuit includes a blue laser drive control circuit.

[0007] The first input terminal of the logic processing circuit is connected to the first output terminal of the modulation controller, and the second input terminal of the logic processing circuit is connected to the second output terminal of the modulation controller. The first output terminal of the logic processing circuit is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller and the green light on / off signal output by the second output terminal of the modulation controller.

[0008] The first input terminal of the selection switch control circuit is connected to the first output terminal of the logic processing circuit, the second input terminal of the selection switch control circuit is connected to the first output terminal of the modulation controller, and the output terminal of the selection switch control circuit is connected to the second input terminal of the blue laser drive control circuit, for outputting a target signal; wherein, the target signal is a fluorescence illumination period signal or a signal for controlling the blue laser to turn on / off, the fluorescence illumination period signal characterizes the signal for turning the blue laser on / off when it is used as an excitation light, and the signal for controlling the blue laser to turn on / off characterizes the signal for turning the blue laser on / off when it is used as an emission light;

[0009] The input terminal of the voltage divider circuit is connected to the first output terminal of the logic processing circuit, and the output terminal of the voltage divider circuit is connected to the first input terminal of the blue laser drive control circuit, for controlling the current of the blue laser drive control circuit during the fluorescence illumination period.

[0010] Preferably, the logic processing circuit includes a first logic circuit, which includes an OR gate, a NOT gate, and an AND gate.

[0011] The first input terminal of the OR gate and the input terminal of the NOT gate are both connected to the first output terminal of the modulation controller;

[0012] The second input terminal of the OR gate is connected to the second output terminal of the modulation controller;

[0013] The output of the OR gate is connected to the first input of the AND gate, the output of the NOT gate is connected to the second input of the AND gate, and the output of the AND gate is connected to the input of the voltage divider circuit.

[0014] Preferably, the expression for the signal output by the first logic circuit is:

[0015]

[0016] Where BY represents the signal output by the first logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal. This indicates that LEDSEL2 is negated.

[0017] Preferably, the voltage divider circuit includes: a first resistor, a switching transistor, and a second resistor;

[0018] The first end of the first resistor is connected to the power supply terminal of the blue laser drive control circuit;

[0019] The second end of the first resistor is connected to the first end of the switching transistor, and both are connected to the first input end of the blue laser driving control circuit;

[0020] The second terminal of the switching transistor is connected to the first output terminal of the logic processing circuit.

[0021] The third terminal of the switching transistor is connected to the first terminal of the second resistor;

[0022] The second terminal of the second resistor is grounded.

[0023] Preferably, the relationship between the output current of the blue laser drive control circuit and the voltage at the power supply terminal of the blue laser drive control circuit is as follows:

[0024] ILED = (Vrefi - 0.2) / 5 / Rcs;

[0025] Wherein, ILED represents the output current of the blue laser drive control circuit, Vrefi represents the voltage value of the power supply terminal of the blue laser drive control circuit after voltage division and sent to the blue laser drive control circuit, and Rcs represents the sampling resistor of the output current of the blue laser drive control circuit.

[0026] Preferably, the logic processing circuit further includes a second logic circuit;

[0027] The second logic circuit includes the OR gate, the first input of the OR gate is connected to the first output of the modulation controller, the second input of the OR gate is connected to the second output of the modulation controller, and the output of the OR gate is connected to the third input of the selection switch control circuit.

[0028] The control pin of the selection switch control circuit is used to send a signal to be output to the second input terminal of the blue laser drive control circuit; wherein, at any time, the signal to be output to the second input terminal of the blue laser drive control circuit is one of the signals output by the first logic circuit, the signals output by the second logic circuit, or the signal used to control the blue laser to turn on / off.

[0029] Preferably, the laser drive control circuit further includes a red laser drive control circuit and a green laser drive control circuit;

[0030] The second output terminal of the modulation controller is connected to the input terminal of the green laser drive control circuit, and is used to output the green laser on / off signal;

[0031] The third output terminal of the modulation controller is connected to the input terminal of the red laser drive control circuit, and is used to output the red laser on / off signal.

[0032] Preferably, the modulation controller is used to output a first lighting sequence, wherein, during the first lighting sequence, red, green, and blue are emitted sequentially within each frame duration, and the red, green, and blue time periods do not overlap.

[0033] Preferably, the modulation controller is used to output a second lighting sequence, wherein, during the second lighting sequence, red laser, green laser, and blue laser are emitted sequentially within each frame duration, and the emission periods of red laser, green laser, and blue laser do not overlap;

[0034] The modulation controller is used to output the third lighting sequence, wherein, during the third lighting sequence, red laser, green laser and blue laser are emitted in a time-division manner within each frame duration, and red laser and green laser overlap, and green laser and blue laser overlap.

[0035] Preferably, the modulation controller is used to output the fourth lighting sequence, wherein, during the fourth lighting sequence, the red laser and the green laser are emitted sequentially in time within each frame duration, and when the green laser is emitted, the blue laser is emitted.

[0036] The expression for the signal output by the second logic circuit is:

[0037] B1 = LEDSEL1 + LEDSEL2;

[0038] Wherein, B1 represents the signal output by the second logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal.

[0039] To solve the above-mentioned technical problems, the present invention provides a projector including the above-mentioned light source control circuit.

[0040] The light source control circuit provided by this invention includes: a laser drive control circuit, a modulation controller, a logic processing circuit, a selection switch control circuit, and a voltage divider circuit; the laser drive control circuit includes a blue laser drive control circuit; the first input terminal of the logic processing circuit is connected to the first output terminal of the modulation controller, and the second input terminal of the logic processing circuit is connected to the second output terminal of the modulation controller. The first output terminal of the logic processing circuit is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller and the green light on / off signal output by the second output terminal of the modulation controller; the first input terminal of the selection switch control circuit is connected to the first output terminal of the logic processing circuit, the second input terminal of the selection switch control circuit is connected to the first output terminal of the modulation controller, and the output terminal of the selection switch control circuit is connected to the second input terminal of the blue laser drive control circuit, for outputting a fluorescence illumination period signal or a blue laser on / off signal. The fluorescence illumination period signal represents the on / off signal when the blue laser is used as excitation light, and the blue laser on / off signal represents the on / off signal when the blue laser is used as emission light. As can be seen, this light source control circuit achieves separate control of the blue laser as both the excitation and emission light. Furthermore, in this control circuit, the input of the voltage divider circuit is connected to the first output of the logic processing circuit, and the output of the voltage divider circuit is connected to the first input of the blue laser drive control circuit. By controlling the current of the blue laser drive control circuit during the fluorescence illumination period, the fluorescence ratio is adjusted. Since the proportion of fluorescence in green affects the color point and color gamut of the image, the adjustable fluorescence ratio can maximize the preservation of the color point and color gamut, thus improving the user's viewing experience.

[0041] In addition, the present invention also provides a projector that has the same or corresponding technical features as the light source control circuit mentioned above, and has the same effect. Attached Figure Description

[0042] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic diagram of a light source control circuit is provided for an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a light mixing control circuit provided in an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of a three-segment timing sequence provided in an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of a five-segment timing sequence provided in an embodiment of the present invention;

[0047] Figure 5 A schematic diagram of a color wheel structure provided in an embodiment of the present invention;

[0048] Figure 6 A schematic diagram of the timing waveform for sequential lighting of RGB three primary color lamps provided in an embodiment of the present invention;

[0049] Figure 7 This is a schematic diagram of the timing waveform of RGB three primary color lamps during white balance calculation, provided for an embodiment of the present invention.

[0050] Figure 8 This is a schematic diagram of another RGB three-primary-color lamp lighting timing waveform provided in an embodiment of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0052] The core of this invention is to provide a light source control circuit and a projector to solve the technical problem that when blue laser light is controlled together as both the output light and the excitation light, it is impossible to meet the user's need to control the blue laser separately or to control the blue laser separately as the excitation light.

[0053] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Figure 1 A schematic diagram of a light source control circuit is provided as an embodiment of the present invention, such as... Figure 1 As shown, the light source control circuit includes: a laser drive control circuit, a modulation controller 10, a logic processing circuit 11, a selection switch control circuit Q1, and a voltage divider circuit 15; the laser drive control circuit includes a blue laser drive control circuit 14.

[0054] The first input terminal of the logic processing circuit 11 is connected to the first output terminal of the modulation controller 10, and the second input terminal of the logic processing circuit 11 is connected to the second output terminal of the modulation controller 10. The first output terminal of the logic processing circuit 11 is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller 10 and the green light on / off signal output by the second output terminal of the modulation controller 10.

[0055] The first input terminal of the selection switch control circuit Q1 is connected to the first output terminal of the logic processing circuit 11, the second input terminal of the selection switch control circuit Q1 is connected to the first output terminal of the modulation controller 10, and the output terminal of the selection switch control circuit Q1 is connected to the second input terminal of the blue laser drive control circuit 14, for outputting a target signal; wherein, the target signal is a fluorescence illumination period signal or a signal for controlling the blue laser to turn on / off, the fluorescence illumination period signal characterizes the blue laser as an excitation light when it is turned on / off, and the signal for controlling the blue laser to turn on / off characterizes the blue laser as an emission light when it is turned on / off;

[0056] The input terminal of the voltage divider circuit 15 is connected to the first output terminal of the logic processing circuit 11, and the output terminal of the voltage divider circuit 15 is connected to the first input terminal of the blue laser drive control circuit 14, which is used to control the current of the blue laser drive control circuit 14 during the fluorescence illumination period.

[0057] The laser drive control circuit is not limited. In this embodiment of the invention, to achieve separate control of the blue laser as the emitted light and the blue laser as the excitation light, the laser drive control circuit includes a blue laser drive control circuit 14. The modulation controller 10 can be a digital micromirror device (DMD) controller or a liquid crystal on silicon (LCD) controller, etc. The modulation controller 10 outputs a signal for controlling the blue laser to turn on / off and a signal for controlling the green light to turn on / off. The signals for controlling the blue laser to turn on / off and the signals for controlling the green light to turn on / off are not limited and can be determined according to the actual situation. It should be noted that the signal for controlling the green light to turn on / off can be a timing signal when the green laser emits light or a timing signal when the green light generated by the blue laser excites fluorescence.

[0058] Meanwhile, a logic processing circuit 11 is set in the light source control circuit to connect the modulation controller 10 and the selection switch control circuit Q1. The logic processing circuit 11 can output a fluorescence illumination period signal characterizing the on / off signal when the blue laser is used as the excitation light and a blue laser on / off signal characterizing the on / off signal when the blue laser is used as the emission light. The fluorescence illumination period is determined based on the on / off signal used to control the blue laser and the on / off signal used to control the green light. Finally, the selection switch control circuit Q1 outputs the fluorescence illumination period signal or the on / off signal used to control the blue laser to the blue laser drive control circuit 14, thereby realizing the separation and separate control of the fluorescence illumination period signal and the on / off signal used to control the blue laser.

[0059] Furthermore, when the fluorescence excited by the blue laser is mixed with the green laser, the proportion of fluorescence will affect the green chromaticity, thus affecting the color gamut and chromaticity of the image. To balance the color gamut, chromaticity, and brightness, the fluorescence mixing ratio needs to be controlled. Generally, the fluorescence proportion can be controlled by adjusting the fluorescence luminescence efficiency excited by the phosphor. In this application, to adjust the fluorescence proportion and ensure the chromaticity and color gamut of the image, a voltage divider circuit 15 connected to the logic processing circuit 11 and the blue laser drive control circuit 14 is set in the light source control circuit. The voltage divider circuit 15 controls the current of the blue laser drive control circuit 14 during the fluorescence illumination period, thereby adjusting the fluorescence proportion.

[0060] The light source control circuit provided in this embodiment of the invention includes: a laser drive control circuit, a modulation controller, a logic processing circuit, a selection switch control circuit, and a voltage divider circuit; the laser drive control circuit includes a blue laser drive control circuit; the first input terminal of the logic processing circuit is connected to the first output terminal of the modulation controller, and the second input terminal of the logic processing circuit is connected to the second output terminal of the modulation controller. The first output terminal of the logic processing circuit is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller and the green light on / off signal output by the second output terminal of the modulation controller; the first input terminal of the selection switch control circuit is connected to the first output terminal of the logic processing circuit, the second input terminal of the selection switch control circuit is connected to the first output terminal of the modulation controller, and the output terminal of the selection switch control circuit is connected to the second input terminal of the blue laser drive control circuit, and is used to output a fluorescence illumination period signal or a blue laser on / off signal. The fluorescence illumination period signal represents the on / off signal when the blue laser is used as excitation light, and the blue laser on / off signal represents the on / off signal when the blue laser is used as emission light. As can be seen, this light source control circuit achieves separate control of the blue laser as both the excitation and emission light. Furthermore, in this control circuit, the input of the voltage divider circuit is connected to the first output of the logic processing circuit, and the output of the voltage divider circuit is connected to the first input of the blue laser drive control circuit. By controlling the current of the blue laser drive control circuit during the fluorescence illumination period, the fluorescence ratio is adjusted. Since the proportion of fluorescence in green affects the color point and color gamut of the image, the adjustable fluorescence ratio can maximize the preservation of the color point and color gamut, thus improving the user's viewing experience.

[0061] Figure 2 This is a schematic diagram of a light mixing control circuit provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the components in the logic processing circuit 11 include AND gates, NOT gates, and OR gates. In some embodiments, the logic processing circuit 11 includes a first logic circuit, which includes OR gates, NOT gates, and AND gates;

[0062] The first input terminal of the OR gate and the input terminal of the NOT gate are both connected to the first output terminal of the modulation controller 10;

[0063] The second input terminal of the OR gate is connected to the second output terminal of the modulation controller 10;

[0064] The output of the OR gate is connected to the first input of the AND gate, the output of the NOT gate is connected to the second input of the AND gate, and the output of the AND gate is connected to the input of the voltage divider circuit 15.

[0065] The fluorescence brightness and color point excited by the blue laser can be obtained through the first logic circuit, which facilitates the calculation of fluorescence white balance.

[0066] The expression (truth value expression) of the signal output by the first logic circuit is:

[0067]

[0068] Where BY represents the signal output by the first logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal. This indicates that LEDSEL2 is negated.

[0069] In some embodiments, such as Figure 2 As shown, the voltage divider circuit 15 includes: a first resistor R1, a switching transistor Q2, and a second resistor R2;

[0070] The first end of the first resistor R1 is connected to the power supply terminal of the blue laser drive control circuit 14;

[0071] The second end of the first resistor R1 is connected to the first end of the switching transistor Q2, and both are connected to the first input end of the blue laser drive control circuit 14.

[0072] The second terminal of the switching transistor Q2 is connected to the first output terminal of the logic processing circuit 11;

[0073] The third terminal of the switching transistor Q2 is connected to the first terminal of the second resistor R2;

[0074] The second terminal of the second resistor R2 is grounded.

[0075] The switching transistor Q2 can be a metal-oxide-semiconductor field-effect transistor (MOSFET), or simply a MOS transistor, or a triode.

[0076] The relationship between the output current of the blue laser drive control circuit 14 and the voltage at the power supply terminal of the blue laser drive control circuit 14 is as follows:

[0077] ILED = (Vrefi - 0.2) / 5 / Rcs;

[0078] Wherein, ILED represents the output current of the blue laser drive control circuit 14, Vrefi represents the voltage value of the power supply terminal of the blue laser drive control circuit 14 after voltage division (i.e., voltage division through the first resistor R1 and the second resistor R2) and is sent to the blue laser drive control circuit 14, and Rcs represents the output current sampling resistor of the blue laser drive control circuit 14.

[0079] This embodiment provides a simple, low-cost circuit for controlling the proportion of fluorescence, offering significant economic value. The specific implementation is as follows: The current driving the blue laser is controlled by the voltage of an input / output (IO) port of the chip. The mixing control logic circuit separates the bright fluorescence duty. A high-level signal to activate the fluorescence is sent to the MOSFET, causing the first and second resistors to conduct, thus dividing the analog voltage and controlling the blue laser current. This solves the problem of different currents in the fluorescent and non-fluorescent segments of the blue laser.

[0080] To improve image brightness and reduce speckle, in some embodiments, such as Figure 2 As shown, the logic processing circuit 11 also includes a second logic circuit;

[0081] The second logic circuit includes an OR gate, the first input of which is connected to the first output of the modulation controller 10, the second input of which is connected to the second output of the modulation controller 10, and the output of which is connected to the third input of the selection switch control circuit Q1.

[0082] The control pin of the selector switch control circuit Q1 is used to send a signal to the selector switch control circuit Q1 to be output to the second input terminal of the blue laser drive control circuit 14; wherein, at any time, the signal to be output to the second input terminal of the blue laser drive control circuit 14 is one of the signals output by the first logic circuit, the signals output by the second logic circuit, or the signals used to control the blue laser to turn on / off.

[0083] For a second logic circuit containing only OR gates, when green and blue light are simultaneously illuminated, part of the blue laser light source illuminates the phosphor region of the color wheel, exciting fluorescence. The excited fluorescence mixes with the green laser in the optical path, which can improve the machine's brightness and reduce speckle. The control pin of the selector switch control circuit Q1 is as follows: Figure 2 The A0 and A1 pins are used. If the A0 pin signal is 0 and the A1 pin signal is 1, the signal BY output by the first logic circuit is output; if the A0 pin signal is 1 and the A1 pin signal is 0, the signal B1 output by the second logic circuit is output; if the A0 pin signal is 1 and the A1 pin signal is 1, the signal B2 used to control the blue laser to turn on / off is output.

[0084] With technological advancements, red and blue laser light sources have been adopted by smart micro-projection products. Projection using RGB lasers can achieve a wider color gamut and richer image color representation. Therefore, this embodiment of the invention employs tri-color lasers for projection.

[0085] In the field of smart micro-projectors, lighting sources have gradually transitioned from mercury lamps and light-emitting diodes (LEDs) to laser light sources. Previously, due to the high cost of red and green laser devices, blue lasers were often used to excite fluorescence by irradiating phosphors, and then red and green colors were filtered out using a filter. Products using this approach had a lower color gamut compared to those using three lasers. With technological advancements, the price of red and blue laser light sources has decreased to a level acceptable for smart micro-projectors. Projections using red, green, and blue (RGB) lasers can achieve a wider color gamut and richer image color representation. However, the coherence of three-color lasers can lead to severe speckle problems, reducing projection brightness and affecting the user experience. To address the technical problems of speckle and low projection brightness caused by three-color lasers in this scenario, based on the above embodiments, the following... Figure 1 and Figure 2 The laser drive control circuit also includes a red laser drive control circuit 12 and a green laser drive control circuit 13.

[0086] The second output terminal of the modulation controller 10 is connected to the input terminal of the green laser drive control circuit 13, and is used to output the green laser on / off signal;

[0087] The third output terminal of the modulation controller 10 is connected to the input terminal of the red laser drive control circuit 12 and is used to output the red laser on / off signal.

[0088] When using three-color lasers for projection, the light source control circuit includes a red laser drive control circuit 12 for driving the red laser, a green laser drive control circuit 13 for driving the green laser, and a blue laser drive control circuit 14 for driving the blue laser. Correspondingly, there are analog voltages to power the red laser drive control circuit 12, the green laser drive control circuit 13, and the blue laser drive control circuit 14, respectively. For example... Figure 1 and Figure 2 In this circuit, analog voltage one is used to power the red laser drive control circuit 12, analog voltage two is used to power the green laser drive control circuit 13, and analog voltage three is used to power the blue laser drive control circuit 14.

[0089] The modulation controller 10 will output the lighting timing sequence for the red laser (e.g., Figure 1 The lighting sequence of LEDSEL0 in the control (e.g., LEDSEL0) and the control of green light (including green light generated by green laser or blue laser excitation of fluorescence) (e.g., LEDSEL0 in the control) Figure 1 LEDSEL1 in the middle) and the lighting sequence of the blue laser (such as...) Figure 1(LEDSEL2 in the example). The lighting sequence is not limited and should be determined based on the actual situation.

[0090] In some embodiments, the modulation controller 10 is used to output a first lighting sequence (also known as a three-segment timing sequence), wherein, during the first lighting sequence, red, green and blue are emitted sequentially within the duration of each frame, and the red, green and blue time periods do not overlap. Figure 3 A schematic diagram of a three-segment timing sequence provided in an embodiment of the present invention, as shown below. Figure 3 As shown, in each frame, the R, G, and B lights turn on and off in a timed manner, which is called the three-stage timing sequence. In the lighting sequence, the red light is lit for 33% of the time, the green light for 34% of the time, and the blue light for 33% of the time.

[0091] In some embodiments, the modulation controller 10 is used to output a second lighting sequence, wherein, during the second lighting sequence, red laser, green laser, and blue laser are emitted sequentially within each frame duration, and the emission periods of the red laser, green laser, and blue laser do not overlap. Figure 3 As shown.

[0092] The modulation controller 10 is used to output the third lighting sequence, in which the red, green, and blue lasers are emitted in a time-sharing manner within each frame duration, with red and green lasers overlapping, and green and blue lasers overlapping as well. When the on / off states of R, G, and B overlap, it is called a five-segment timing sequence. Figure 4 A schematic diagram of a five-segment timing sequence provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the five-segment timing sequence is composed of five colors: red (R), green (G), blue (B), yellow (Y), and cyan (C) to create other colors. In the light-on sequence, the red light is on for 20% of the time, the yellow light for 18%, the green light for 25%, the cyan light for 12%, and the blue light for 25%. Because the five-segment timing sequence results in a greater duty cycle for the R, G, and B lights in each frame compared to a three-segment timing sequence, the projection brightness is higher, making the product more competitive in terms of brightness. Therefore, a five-segment timing sequence can be selected in implementation.

[0093] The following is an explanation of a color wheel mixing scheme. Figure 5 A schematic diagram of a color wheel structure provided in an embodiment of the present invention is shown below. Figure 5 As shown, the color wheel contains alternating blue reflective and fluorescent areas. When the color wheel rotates 180°, it outputs one frame of image. When the color wheel rotates to the wheel speed detection mark block, the speed detection circuit outputs a high-level pulse. The image display control processor detects the speed pulse and synchronously outputs a timing waveform for the RGB three primary color lamps to light up in sequence. Figure 6 This is a schematic diagram of the timing waveform for sequentially lighting RGB three-primary-color lamps, provided by an embodiment of the present invention. Figure 6As shown, the speed detection circuit outputs a high-level pulse, and the image display control processor detects the speed pulse and synchronously outputs a timing waveform for the RGB three primary color lamps to light up in sequence.

[0094] When the first logic circuit outputs the signal BY, the power supply voltage at the power supply terminal of the red laser drive control circuit 12 and the power supply voltage at the power supply terminal of the green laser drive control circuit 13 are both 0, that is, the red and green laser light sources are turned off. Figure 7 This is a schematic diagram of the timing waveforms of RGB three-primary-color lamps during white balance calculation, provided as an embodiment of the present invention. Figure 7 As shown, the expression for the signal BY output by the second logic circuit can yield a timing sequence containing only fluorescence. By obtaining the fluorescence brightness and color point of blue laser excitation, it is convenient to perform on-fluorescence white balance calculation.

[0095] In the modulation controller 10, the fourth lighting sequence is output. During the fourth lighting sequence, the red laser and the green laser are emitted sequentially in time within each frame duration, and the blue laser is emitted when the green laser is emitted.

[0096] The expression for the signal output by the second logic circuit is:

[0097] B1 = LEDSEL1 + LEDSEL2;

[0098] Where B1 represents the signal output by the second logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal.

[0099] Figure 8 This is a schematic diagram of another RGB three-primary-color lamp lighting timing waveform provided in an embodiment of the present invention, as shown below. Figure 8 As shown, the blue laser starts shining when the green laser begins to light up. Part of the blue laser light source illuminates the phosphor region of the color wheel, exciting it to fluoresce. The excited fluorescence mixes with the green laser in the optical path, which can increase the brightness of the machine and reduce speckle, thus improving the user's viewing experience.

[0100] The above describes a light source control circuit. This embodiment also provides a projector including the aforementioned light source control circuit. The light source control circuit includes: a laser drive control circuit, a modulation controller, a logic processing circuit, a selection switch control circuit, and a voltage divider circuit. The laser drive control circuit includes a blue laser drive control circuit. The first input terminal of the logic processing circuit is connected to the first output terminal of the modulation controller, and the second input terminal of the logic processing circuit is connected to the second output terminal of the modulation controller. The first output terminal of the logic processing circuit is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller and the green light on / off signal output by the second output terminal of the modulation controller. The first input terminal of the selection switch control circuit is connected to the first output terminal of the logic processing circuit, the second input terminal of the selection switch control circuit is connected to the first output terminal of the modulation controller, and the output terminal of the selection switch control circuit is connected to the second input terminal of the blue laser drive control circuit, used to output a fluorescence illumination period signal or a blue laser on / off signal. The fluorescence illumination period signal represents the on / off signal when the blue laser is used as the excitation light, while the control signal for the blue laser's on / off signal represents the on / off signal when the blue laser is used as the emission light. It can be seen that this light source control circuit achieves separate control of the blue laser when used as the excitation light and when used as the emission light. Furthermore, in this light source control circuit, the input terminal of the voltage divider circuit is connected to the first output terminal of the logic processing circuit, and the output terminal of the voltage divider circuit is connected to the first input terminal of the blue laser drive control circuit. By controlling the current of the blue laser drive control circuit during the fluorescence illumination period, the fluorescence ratio is adjusted. Since the proportion of fluorescence in green affects the color point and color gamut of the image, based on the adjustable fluorescence ratio, the color point and color gamut of the image can be guaranteed as much as possible, improving the user's viewing experience.

[0101] The foregoing has provided a detailed description of a light source control circuit and a projector provided by the present invention. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the present invention.

[0102] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A light source control circuit, characterized in that, include: The system includes a laser drive control circuit, a modulation controller, a logic processing circuit, a selection switch control circuit, and a voltage divider circuit; the laser drive control circuit includes a blue laser drive control circuit. The first input terminal of the logic processing circuit is connected to the first output terminal of the modulation controller, and the second input terminal of the logic processing circuit is connected to the second output terminal of the modulation controller. The first output terminal of the logic processing circuit is used to determine the fluorescence illumination period based on the blue laser on / off signal output by the first output terminal of the modulation controller and the green light on / off signal output by the second output terminal of the modulation controller. The first input terminal of the selection switch control circuit is connected to the first output terminal of the logic processing circuit, the second input terminal of the selection switch control circuit is connected to the first output terminal of the modulation controller, and the output terminal of the selection switch control circuit is connected to the second input terminal of the blue laser drive control circuit, for outputting a target signal; wherein, the target signal is a fluorescence illumination period signal or a signal for controlling the blue laser to turn on / off, the fluorescence illumination period signal characterizes the signal for turning the blue laser on / off when it is used as an excitation light, and the signal for controlling the blue laser to turn on / off characterizes the signal for turning the blue laser on / off when it is used as an emission light; The input terminal of the voltage divider circuit is connected to the first output terminal of the logic processing circuit, and the output terminal of the voltage divider circuit is connected to the first input terminal of the blue laser drive control circuit, for controlling the current of the blue laser drive control circuit during the fluorescence illumination period.

2. The light source control circuit according to claim 1, characterized in that, The logic processing circuit includes a first logic circuit, which includes an OR gate, a NOT gate, and an AND gate. The first input terminal of the OR gate and the input terminal of the NOT gate are both connected to the first output terminal of the modulation controller; The second input terminal of the OR gate is connected to the second output terminal of the modulation controller; The output of the OR gate is connected to the first input of the AND gate, the output of the NOT gate is connected to the second input of the AND gate, and the output of the AND gate is connected to the input of the voltage divider circuit.

3. The light source control circuit according to claim 2, characterized in that, The expression for the signal output by the first logic circuit is: Where BY represents the signal output by the first logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal. This indicates that LEDSEL2 is negated.

4. The light source control circuit according to any one of claims 1 to 3, characterized in that, The voltage divider circuit includes: a first resistor, a switching transistor, and a second resistor; The first end of the first resistor is connected to the power supply terminal of the blue laser drive control circuit; The second end of the first resistor is connected to the first end of the switching transistor, and both are connected to the first input end of the blue laser driving control circuit; The second terminal of the switching transistor is connected to the first output terminal of the logic processing circuit. The third terminal of the switching transistor is connected to the first terminal of the second resistor; The second terminal of the second resistor is grounded.

5. The light source control circuit according to claim 1, characterized in that, The relationship between the output current of the blue laser drive control circuit and the voltage at the power supply terminal of the blue laser drive control circuit is as follows: ILED = (Vrefi - 0.2) / 5 / Rcs; Wherein, ILED represents the output current of the blue laser drive control circuit, Vrefi represents the voltage value of the power supply terminal of the blue laser drive control circuit after voltage division and sent to the blue laser drive control circuit, and Rcs represents the sampling resistor of the output current of the blue laser drive control circuit.

6. The light source control circuit according to claim 2, characterized in that, The logic processing circuit also includes a second logic circuit; The second logic circuit includes the OR gate, the first input of the OR gate is connected to the first output of the modulation controller, the second input of the OR gate is connected to the second output of the modulation controller, and the output of the OR gate is connected to the third input of the selection switch control circuit. The control pin of the selection switch control circuit is used to send a signal to be output to the second input terminal of the blue laser drive control circuit; wherein, at any time, the signal to be output to the second input terminal of the blue laser drive control circuit is one of the signals output by the first logic circuit, the signals output by the second logic circuit, or the signal used to control the blue laser to turn on / off.

7. The light source control circuit according to claim 6, characterized in that, The laser drive control circuit also includes a red laser drive control circuit and a green laser drive control circuit. The second output terminal of the modulation controller is connected to the input terminal of the green laser drive control circuit, and is used to output the green laser on / off signal; The third output terminal of the modulation controller is connected to the input terminal of the red laser drive control circuit, and is used to output the red laser on / off signal.

8. The light source control circuit according to claim 1, characterized in that, The modulation controller is used to output a first lighting sequence, wherein, during the first lighting sequence, red, green and blue are emitted sequentially within the duration of each frame, and the red, green and blue time periods do not overlap.

9. The light source control circuit according to claim 7, characterized in that, The modulation controller is used to output the second lighting sequence, wherein, during the second lighting sequence, red laser, green laser, and blue laser are emitted sequentially within each frame duration, and the emission periods of red laser, green laser, and blue laser do not overlap; The modulation controller is used to output the third lighting sequence, wherein, during the third lighting sequence, red laser, green laser and blue laser are emitted in a time-division manner within each frame duration, and red laser and green laser overlap, and green laser and blue laser overlap.

10. The light source control circuit according to claim 7, characterized in that, The modulation controller is used to output the fourth lighting sequence, wherein, during the fourth lighting sequence, the red laser and the green laser are emitted sequentially in time division within each frame duration, and when the green laser is emitted, the blue laser is emitted. The expression for the signal output by the second logic circuit is: B1 = LEDSEL1 + LEDSEL2; Wherein, B1 represents the signal output by the second logic circuit, LEDSEL1 represents the green light lighting control signal, and LEDSEL2 represents the blue laser lighting control signal.

11. A projector, characterized in that, Includes the light source control circuit according to any one of claims 1 to 10.

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