Projection apparatus and driving method

Abstract

The invention provides projection equipment and a driving method, and belongs to the technical field of projection equipment. The projection equipment comprises a display control circuit, a color wheel driving circuit and a color wheel motor, and the display control circuit is configured to acquire a video period signal, acquire an actual driving parameter of the color wheel motor, output a color wheel control signal based on the video period signal, and adjust a reference driving parameter based on the actual driving parameter. The color wheel driving circuit is electrically connected with the display control circuit and is configured to receive a color wheel control signal and the adjusted reference driving parameters and generate a color wheel driving signal based on the color wheel control signal and the adjusted reference driving parameters, and the color wheel motor is fixedly connected with the color wheel and is electrically connected with the color wheel driving circuit; the driving module is configured to receive the color wheel driving signal and drive the color wheel to rotate based on the color wheel driving signal. Therefore, the color wheel can rotate according to the required frequency under the control of the display control circuit.

Description

Technical Field

[0001] This application relates to the field of projection equipment technology. More specifically, it relates to a projection device and a driving method. Background Technology

[0002] Currently, in the process of displaying the image to be projected, the projection device controls the output of laser light from the light source, and controls the laser to pass through the color wheel to output light sources of different colors. The light source is dimmed by the light valve, and the beam passes through the projection lens to be projected onto the projection screen to display the corresponding image.

[0003] To ensure display accuracy, a display control circuit is usually provided to adjust the rotation frequency of the color wheel and the working process of the light valve, so as to ensure that the projection device accurately outputs the display of each frame of the image.

[0004] However, even under the control of the display control circuit, the color wheel still could not rotate at the required frequency. Summary of the Invention

[0005] This application provides a projection device and driving method that enables a color wheel to rotate at a required frequency under the control of a display control circuit.

[0006] This application provides a projection device, which includes:

[0007] The light source is configured to emit a monochromatic laser beam;

[0008] The color wheel is configured to emit lasers of various colors along different optical paths after being irradiated by a laser beam;

[0009] The light valve is configured to modulate the colored light beam emitted by the color wheel and project the image beam to the projection lens;

[0010] The projection lens is configured to image the incident laser beam;

[0011] Projection devices also include:

[0012] The display control circuit is configured to acquire the video cycle signal and the actual driving parameters of the color wheel motor, output the color wheel control signal based on the video cycle signal, and adjust the reference driving parameters based on the actual driving parameters.

[0013] The color wheel drive circuit, electrically connected to the display control circuit, is configured to receive the color wheel control signal and the adjusted reference drive parameters, and generate the color wheel drive signal based on the color wheel control signal and the adjusted reference drive parameters;

[0014] A color wheel motor, fixedly connected to the color wheel and electrically connected to the color wheel drive circuit, is configured to receive the color wheel drive signal and drive the color wheel to rotate based on the color wheel drive signal.

[0015] In the above technical solution, the color wheel drive circuit generates a drive signal based on the control signal output by the display control circuit and the reference drive parameters of the color wheel motor. Since the effect of temperature on the motor's drive performance is mainly reflected in the change of drive parameters, if the color wheel drive circuit still generates a drive signal based on the original reference drive parameters, the color wheel motor will not be able to rotate at the preset frequency. By adjusting the reference drive parameters according to the actual drive parameters, the color wheel drive circuit generates a drive signal based on the adjusted reference drive parameters. In this way, the influence of temperature on motor performance can be adapted, and the motor speed can meet the required frequency.

[0016] In some embodiments, the display control circuit is configured to:

[0017] When the actual driving parameters are greater than the reference driving parameters, the reference driving parameters are not adjusted.

[0018] When the actual driving parameters are less than or equal to the reference driving parameters, adjust the reference driving parameters.

[0019] In the above technical solution, adjusting the reference drive parameters only when the color wheel motor cannot achieve the required driving performance can reduce the data transmission of the display control circuit, improve the response performance of the projection device, and also reduce the power consumption of the device.

[0020] In some embodiments, the display control circuit is configured to:

[0021] When the actual driving parameters are less than or equal to the reference driving parameters, reduce the reference driving parameters.

[0022] In some embodiments, the display control circuit is configured to:

[0023] When the actual driving parameter is less than or equal to the reference driving parameter, reduce the reference driving parameter so that the reference driving parameter is less than the actual driving parameter.

[0024] In some embodiments, the display control circuit includes:

[0025] The adjustment circuit, electrically connected to the color wheel motor, is configured to acquire the actual driving parameters of the color wheel motor and generate an adjustment signal based on the actual driving parameters.

[0026] The control circuit, electrically connected to the adjustment circuit and the color wheel drive circuit, is configured to adjust the reference drive parameters according to the adjustment signal and send the adjusted reference drive parameters to the color wheel drive circuit.

[0027] In some embodiments, the regulating circuit includes:

[0028] The conversion device, electrically connected to the neutral point of the winding of the color wheel motor, is configured to acquire the back electromotive force of the color wheel motor and generate the actual driving parameters of the color wheel motor based on the back electromotive force of the color wheel motor.

[0029] The comparator circuit has a first input terminal connected to the output terminal of the conversion device, and a second input terminal receiving reference driving parameters. It is configured to generate an adjustment signal based on the actual driving parameters and the reference driving parameters.

[0030] In some embodiments, the comparison circuit includes:

[0031] An operational amplifier, with its first input terminal electrically connected to the output terminal of the conversion device, and its second input terminal receiving reference drive parameters, is configured to output an adjustment signal from the output terminal.

[0032] The feedback resistor has its first end electrically connected to the second input terminal of the operational amplifier, and its second end electrically connected to the output terminal of the operational amplifier.

[0033] In some embodiments, the switching device is configured to:

[0034] Calculate the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor;

[0035] The actual drive parameters are determined based on the ratio between the back electromotive force of the color wheel motor and the speed of the color wheel motor, and a preset coefficient.

[0036] In some embodiments, the color wheel drive circuit includes:

[0037] The excitation control circuit, which is electrically connected to the display control circuit, is configured to generate a bridge arm control signal based on the color wheel control signal and the adjusted reference drive parameters.

[0038] The bridge arm switching circuit is electrically connected to the excitation control circuit at its control terminal, receives DC power at its DC terminal, and is electrically connected to the electrical terminal of the color wheel motor at its AC terminal. It is configured to provide excitation voltage to the electrical terminal of the color wheel motor based on the bridge arm control signal.

[0039] In some embodiments, the color wheel drive circuit further includes:

[0040] The feedback circuit, electrically connected to the color wheel motor and the excitation control circuit, is configured to acquire the actual speed of the color wheel motor, generate a speed difference based on the actual speed and the target speed of the color wheel motor, generate a difference control signal based on the speed difference, and output the difference control signal to the excitation control circuit.

[0041] In some embodiments, the feedback circuit includes:

[0042] The speed operational amplifier has its first input terminal electrically connected to the color wheel motor, its second input terminal receiving the target speed, and is configured to output the speed difference of the color wheel motor.

[0043] The speed regulation circuit, electrically connected to the output of the speed operational amplifier, is configured to generate a voltage signal based on the speed difference of the color wheel motor;

[0044] The speed control circuit has a first input terminal electrically connected to the speed regulation circuit, and a second input terminal receiving a reference voltage. It is configured to generate a difference control signal based on the voltage signal and the reference voltage, and then send the difference control signal to the excitation control circuit.

[0045] In some embodiments, the color wheel includes a fluorescent color wheel, and the display control circuit is configured to adjust the reference driving parameters of the fluorescent color wheel based on the actual driving parameters of the fluorescent color wheel;

[0046] The color wheel drive circuit includes a fluorescent color wheel drive circuit, which is configured to receive a color wheel control signal and adjusted reference drive parameters, and generate a color wheel drive signal based on the color wheel control signal and the adjusted reference drive parameters.

[0047] Some embodiments of this application provide a driving method for a projection device, the projection device including:

[0048] The light source is configured to emit a monochromatic laser beam;

[0049] The color wheel is configured to emit lasers of various colors along different optical paths after being irradiated by a laser beam;

[0050] The light valve is configured to modulate the colored light beam emitted by the color wheel and project the image beam to the projection lens;

[0051] The projection lens is configured to image the incident laser beam;

[0052] The driving methods include:

[0053] Acquire the video cycle signal and the actual driving parameters of the color wheel motor, output the color wheel control signal based on the video cycle signal, and adjust the reference driving parameters based on the actual driving parameters;

[0054] Among them, the color wheel control signal and the adjusted reference drive parameters are used to generate the color wheel drive signal, which is used to drive the color wheel to rotate.

[0055] In some embodiments, adjusting the reference driving parameters based on the actual driving parameters specifically includes:

[0056] When the actual driving parameters are greater than the reference driving parameters, the reference driving parameters are not adjusted.

[0057] When the actual driving parameters are less than or equal to the reference driving parameters, adjust the reference driving parameters.

[0058] In some embodiments, when the actual driving parameter is less than or equal to the reference driving parameter, adjusting the reference driving parameter specifically includes:

[0059] When the actual driving parameters are less than or equal to the reference driving parameters, reduce the reference driving parameters.

[0060] In some embodiments, when the actual driving parameter is less than or equal to the reference driving parameter, the reference driving parameter is reduced, specifically including:

[0061] When the actual driving parameter is less than or equal to the reference driving parameter, reduce the reference driving parameter so that the reference driving parameter is less than the actual driving parameter.

[0062] In some embodiments, obtaining the actual driving parameters of the color wheel motor specifically includes:

[0063] Obtain the back electromotive force of the color wheel motor, and generate the actual driving parameters of the color wheel motor based on the back electromotive force.

[0064] In some embodiments, the actual driving parameters of the color wheel motor are generated based on the back electromotive force of the color wheel motor, specifically including:

[0065] Calculate the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor;

[0066] The actual drive parameters are determined based on the ratio between the back electromotive force of the color wheel motor and the speed of the color wheel motor, and a preset coefficient.

[0067] Some embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the methods provided in the above embodiments.

[0068] Some embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the above embodiments. Attached Figure Description

[0069] To more clearly illustrate the implementation methods in the embodiments of this application or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0070] Figure 1 This is an application scenario diagram of a laser projection system provided in this application according to an exemplary embodiment;

[0071] Figure 2 This is an application scenario diagram of a laser projection system provided in this application according to another exemplary embodiment;

[0072] Figure 3 A schematic diagram illustrating the principle of a laser light source that emits light in conjunction with a fluorescent color wheel and a color filter wheel, as provided in this application;

[0073] Figure 4 This application provides a schematic diagram of the structure of a fluorescent color wheel;

[0074] Figure 5 This application provides a schematic diagram of the structure of a color filter wheel;

[0075] Figure 6 A schematic diagram of another fluorescent color wheel and filter wheel provided in this application;

[0076] Figure 7 This application provides a schematic diagram of the structure of a sensor;

[0077] Figure 8 This is a schematic diagram of the structure of a projection device according to some embodiments of this application;

[0078] Figure 9 This is a schematic diagram of the structure of a projection device according to other embodiments of this application;

[0079] Figure 10 This is a schematic diagram of the structure of a projection device according to some embodiments of this application;

[0080] Figure 11 This is a schematic diagram of the structure of a projection device according to some embodiments of this application.

[0081] Figure 12 This is a schematic diagram of the structure of a projection device according to some embodiments of this application;

[0082] Figure 13 This is a schematic diagram of the structure of a projection device according to some embodiments of this application;

[0083] Figure 14 Flowcharts of driving methods for projection devices provided in some embodiments of this application;

[0084] Figure 15 A flowchart of a driving method for a projection device provided in other embodiments of this application.

[0085] Figure label:

[0086] 101. Light source; 102. First focusing lens; 103. Dichroic mirror; 310. Phosphor wheel; 311. Yellow phosphor area; 312. Green phosphor area; 313. First transparent area; 104. Mirror; 105. Second focusing lens; 320. Color filter wheel; 321. Red light-transmitting area; 322. Yellow light-transmitting area; 323. Second transparent area; 324. Green light-transmitting area; 106. Light guide; 107. Total internal reflection prism; 108. Light valve; 109. Projection lens; 10. Display control circuit ; 110, Adjustment circuit; 120, Control circuit; 20, Color wheel drive circuit; 210, Excitation control circuit; 220, Bridge arm conversion circuit; 230, Feedback circuit; 231, Speed ​​operational amplifier; 232, Speed ​​adjustment circuit; 233, Speed ​​control circuit; 30, Color wheel; 40, Speed ​​sensor; 50, Shaping circuit; 60, Enable control unit; 70, Multimedia chip; 90, Laser drive circuit; Vsync, Field synchronization period signal; 111, Converter; 112, Comparator circuit. Detailed Implementation

[0087] To make the objectives, implementation methods and advantages of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only some embodiments of this application, and not all embodiments.

[0088] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0089] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclusively include, for example, a product or device that includes a series of components is not necessarily limited to those that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such product or device.

[0090] The technical solutions of this application will be described in detail below with reference to specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0091] Figure 1 and Figure 2 This is an application scenario diagram of a projection device provided in this application according to an exemplary embodiment, such as... Figure 1 and Figure 2 As shown, the user can operate the projection device 100 through the smart device 1003 or the control device 1005 to project images or videos onto the screen 1000.

[0092] In some embodiments, the number of projection devices 100 may be multiple. When the laser projection system projects a projection image on the screen 1000, each projection device 100 projects a portion of the projection image on the screen 1000 and sets an overlapping area in two adjacent images to display the same image, so as to achieve image connection. By splicing multiple projection images on the screen 1000, a complete projection image is formed.

[0093] In some embodiments, the control device 1005 may be a remote control. Communication between the remote control and the projection device 100 includes infrared protocol communication, Bluetooth protocol communication, and other short-range communication methods, controlling the projection device 100 wirelessly or via wired means. Users can input user commands through buttons on the remote control, voice input, control panel input, etc., to control the projection device 100.

[0094] In some embodiments, a smart device 1003 (such as a mobile terminal, tablet computer, computer, laptop computer, etc.) may also be used to control the projection device 100. For example, an application running on the smart device may be used to control the projection device 100.

[0095] In some embodiments, the projection device 100 may receive instructions not through the aforementioned smart device or control device, but through gestures or the like.

[0096] In some embodiments, the projection device 100 can also be controlled in ways other than the control device 1005 and the smart device 1003. For example, it can be controlled by directly receiving the user's voice commands through a module configured inside the projection device 100 for acquiring voice commands, or it can be controlled by receiving the user's voice commands through a voice control device set outside the projection device 100.

[0097] In some embodiments, the projection device 100 also communicates with the server 1004. The projection device 100 may communicate via a local area network (LAN), wireless local area network (WLAN), and other networks. The server 1004 may provide various content and interactive features to the projection device 100. The server 1004 may be a cluster or multiple clusters, and may include one or more types of servers.

[0098] Some embodiments of this application provide a projection device including a main control circuit configured to obtain data to be projected and to parse the data to be projected to obtain a video periodic signal.

[0099] In some embodiments, the projection device may include a display control circuit and a main control circuit electrically connected, configured to output a color indication signal, a color wheel control signal, and a light valve control signal based on a video periodic signal.

[0100] In some embodiments, the projection device includes a light source, and the light source and display control circuitry are electrically connected and configured to emit a laser beam based on a color indication signal.

[0101] In some embodiments, the projection device includes a color wheel drive circuit and a color wheel, the color wheel including a filter wheel and a fluorescent wheel, the color wheel drive circuit and the display control circuit are electrically connected, and are configured to control the rotation of the filter wheel and the fluorescent wheel based on the color wheel control signal, so that the laser beam provided by the light source passes through the fluorescent wheel and the filter wheel, and outputs light of the color corresponding to the current video.

[0102] In some embodiments, the projection device includes a light valve driving circuit, which is electrically connected to a display control circuit. It is configured to adjust the flip angle of each light mirror based on a light valve control signal so that the light beam provided by the color wheel is projected onto the light mirror. The light beam is adjusted by reflection, and the light beam passing through the projection lens is projected onto the screen to display the projected image.

[0103] For example, Figure 3 This application provides a schematic diagram of a laser light source 101 that emits light in conjunction with a fluorescent color wheel 310 and a color filter wheel 320. Figure 4 This is a schematic diagram of the structure of the fluorescent color wheel 310. Figure 5 This is a schematic diagram of the color filter wheel 320. The following is in conjunction with... Figure 3 , Figure 4 as well as Figure 5 The principle of how the laser light source 101 works in conjunction with the fluorescent color wheel 310 and the color filter wheel 320 to output primary color light is introduced.

[0104] Reference Figure 3 It includes a laser light source 101, a first focusing lens 102, a dichroic mirror 103, a fluorescent color wheel 310, a reflector 104, a second focusing lens 105, a color filter wheel 320, a light guide 106, a total reflection prism 107, a light valve 108, and a projection lens 109.

[0105] The fluorescent color wheel 310 may include a plurality of first sub-regions, the number of which is related to the number of primary colors, and each primary color may correspond to at least one first sub-region on the fluorescent color wheel 310. Specifically, after receiving a light beam emitted by the light source 101, the at least one first sub-region on the fluorescent color wheel 310 corresponding to each primary color can output a light beam for generating that primary color. (Reference) Figure 4The phosphor color wheel 310 has multiple first sub-regions, including a yellow phosphor region 311, a green phosphor region 312, and a first transparent region 313. The phosphor color wheel 310 includes a phosphor color wheel motor 315 and a phosphor color wheel substrate disk 316. The rotor of the phosphor color wheel motor 315 and the phosphor color wheel substrate disk 316 are bonded together with adhesive, allowing the phosphor color wheel motor 315 to drive the phosphor color wheel substrate disk 316 to rotate. Multiple first sub-regions are provided on one surface of the phosphor color wheel substrate disk 316 away from the phosphor color wheel motor 315.

[0106] The color filter wheel 320 may also include multiple second sub-regions, the number of which corresponds to the number of first sub-regions on the fluorescent color wheel 310, to generate beams of different colors. (Reference) Figure 5 The color filter wheel 320 includes multiple second sub-regions, including a red light-transmitting region 321, a yellow light-transmitting region 322, a second transparent region 323, and a green light-transmitting region 324. The structure of the color filter wheel 320 is the same as that of the color filter motor 324. The color filter wheel 320 includes a color filter motor 324 and a color filter substrate disk 325. The rotor of the color filter motor 324 and the color filter substrate disk 325 are connected by adhesive, so that the color filter motor 324 can drive the color filter substrate disk 325 to rotate.

[0107] The projected colors are generally composed of four primary colors: red, green, blue, and yellow (RGBY). The generation process of these four primary colors is as follows: A blue monochromatic laser is used. A green phosphor area 312, a yellow phosphor area 311, and a first transparent area 313 are set on the phosphor color wheel 310. The first transparent area 313 is used to transmit blue laser light. Correspondingly, a green light-transmitting area 324 is set on the filter wheel 320, a red light-transmitting area 321 is used to filter red light from yellow phosphor, a yellow light-transmitting area 322 is used to transmit yellow light, and a second transparent area 323 is used to transmit blue laser light. When the two color wheels 30 rotate synchronously, the four colors (RGBY) are output sequentially.

[0108] In some embodiments, such as Figure 6 As shown, the angle of the green phosphor region on the fluorescent color wheel is 30°, the angle of the yellow phosphor region is 96°, and the angle of the first transparent region is 54°. Correspondingly, the angle of the green transparent region on the color filter wheel is 30°, the angle of the red transparent region is 33°, the angle of the yellow transparent region is 63°, and the angle of the second transparent region is 54°.

[0109] like Figure 3As shown, the optical path for emitting blue light is as follows: The monochromatic laser emitted by the light source 101 is reflected by one side of the dichroic mirror 103, passes through the first transparent area 313 on the fluorescent color wheel 310, is reflected by three reflecting mirrors 104, and is then reflected by the other side of the dichroic mirror 103 before reaching the second focusing lens 105. After passing through the second focusing lens 105, the light still appears blue in the second transparent area 323 of the filter color wheel 320.

[0110] like Figure 3 As shown, the optical path for emitting green light is as follows: Monochromatic laser light emitted from light source 101 is reflected by one side of dichroic mirror 103 and illuminates the green phosphor region 312 on the phosphor color wheel 310, generating green fluorescence. This green fluorescence passes directly through dichroic mirror 103 and reaches the second focusing lens 105. After passing through the second focusing lens 105, it is purified by the green light-transmitting region 324 of the filter color wheel 320, resulting in the output of green light.

[0111] like Figure 3 As shown, the optical path for emitting yellow light is as follows: Monochromatic laser light emitted from light source 101 is reflected by one side of dichroic mirror 103 and strikes the yellow phosphor region 311 on the phosphor color wheel 310, generating yellow fluorescence. This yellow fluorescence passes directly through dichroic mirror 103 and reaches the second focusing lens 105. After passing through the second focusing lens 105, a portion of the yellow fluorescence passes through the red light-transmitting region 321 of the filter color wheel 320 to output red light, while a portion passes through the yellow light-transmitting region 322 of the filter color wheel 320 to output yellow light.

[0112] by Figure 4 Taking the color zone division on the fluorescent color wheel 310 as an example, when the fluorescent color wheel 310 is rotated counterclockwise, yellow fluorescence, green fluorescence, and blue laser light can be generated sequentially. Figure 5 Taking the color zone division on the color filter wheel 320 as an example, when the color filter wheel 320 rotates counterclockwise, and in conjunction with the aforementioned fluorescent color wheel 310 rotates counterclockwise, the final output light color sequence can be red, green, blue, and yellow. Among them, red, green, and blue are used to present the projected image, and yellow is used to increase the brightness of the image, so as to realize the replacement of the three-color LED light source 101 with the four-primary-color light source 101 of the monochromatic laser eight-segment color wheel 30.

[0113] Furthermore, the timing of the output light color is related to the color zone distribution on the two color wheels 30, and the initial output light color is related to the starting point of rotation of the two color wheels 30. This application does not limit the timing of the output light color; in practical applications, it must be matched with the timing of the color requirements of the video cycle signal being analyzed by the front end.

[0114] Afterwards, the output light color is homogenized by the light guide 106. The homogenized light undergoes total internal reflection on the total internal reflection prism 107 and illuminates the light valve 108, which then reflects it into the projection lens 109 to project the image.

[0115] To ensure the accuracy of the target color display, the fluorescent color wheel 310, the color filter wheel 320 and the light source 101 need to cooperate with each other. The correspondence between the regions constructed by the rotation of the fluorescent color wheel 310 and the color filter wheel 320, as well as the emission of the laser, need to be guaranteed.

[0116] The projection device is equipped with a first speed sensor and a second speed sensor corresponding to the fluorescent color wheel 310 and the color filter wheel 320, respectively. The fluorescent color wheel 310 is marked with a first indicator. The color filter wheel 320 is marked with a second indicator. These indicators typically serve two functions: first, to detect the rotational speed of the color wheel 30; and second, the indicator's position is usually aligned with the color zones of the color wheel 30, allowing the system to determine the initial time of a particular color by detecting the arrival of the indicator signal pulse.

[0117] The rotational speeds of the fluorescent color wheel 310 and the filter wheel 320 are detected using a reflective infrared sensor. (Reference) Figure 7 The sensor structure shown is explained below, along with its operation. The reflective infrared sensor N1 has one infrared emitter (VD1) and one infrared receiver (V1). When the infrared emitter projects light onto a highly reflective object (e.g., a white surface), the infrared light is reflected back, and the infrared receiver can receive this periodic infrared signal, causing the sensor to output a low level (CW_INDEX_O). When the infrared emitter projects light onto a low-reflective object (e.g., a black surface), the infrared light is absorbed by the black surface, and the infrared receiver cannot receive this periodic infrared signal, causing the sensor to output a high level (CW_INDEX_O). The reflective infrared sensor generates pulse signals based on the presence or absence of reflected light.

[0118] In some embodiments, the infrared emitting device (VD1) includes a light-emitting transistor, and the infrared receiving device (V1) includes a phototransistor. The light-emitting transistor can provide a light signal so that when the light signal reaches the light-reflecting surface, it is reflected based on its reflection characteristics and projected onto the phototransistor. The phototransistor controls its conduction state based on the light intensity, thereby adjusting the voltage value of its output terminal (the collector of the transistor in the figure).

[0119] In some embodiments, the infrared receiving device (V1) includes a phototransistor. The light signal reflected by the light reflector is projected onto the phototransistor, and the phototransistor controls its conduction state based on the light intensity, thereby adjusting the voltage value at its output terminal (the collector of the transistor in the figure).

[0120] The fluorescent color wheel 310 and the color filter wheel 320 each have a marker on their main body, usually black. The black marker has low reflectivity and absorbs infrared detection light. The surfaces other than the black marker are either highly reflective or translucent. Each rotation of the fluorescent color wheel 310 and the color filter wheel 320 generates a pulse signal. This pulse signal is periodic; therefore, by detecting the frequency of the pulse, the motor speed and the color partition position of the color wheel 30 can be monitored.

[0121] The aforementioned projection device uses a single laser light source 101 to excite the yellow and green phosphors on the phosphor color wheel 310. Then, the color wavelength is selected by the filter color wheel 320, and after color purification filtration, four kinds of light—red, green, blue, and yellow—are generated in sequence. These light are then refracted onto the light valve by various optical lenses such as prisms, and finally projected onto the lens to produce an image.

[0122] When the light beam shines on the color wheel 30, it generates a lot of heat. The heat is transferred through the color wheel substrate disk and the adhesive to the rotor (magnet) of the color wheel motor. When the heat causes the magnet of the color wheel motor to exceed the temperature specification for a long time, the magnetic flux of the magnet will decrease. The decrease in magnetic flux will cause the driving parameter KT of the motor to decrease. When the driving parameter KT decreases to a certain extent, the driving parameter of the color wheel 30 will become mismatched with the color wheel 30, resulting in a decrease in the rotation speed of the color wheel 30. As a result, the two color wheels 30 may not reach the preset color boundary at the same time, that is, the two color wheels 30 are misaligned, and finally the image color is disordered, and the machine cannot be viewed normally.

[0123] In view of this, some embodiments of this application provide a driving method, projection device, storage medium, and program product that enable the color wheel to rotate at a required frequency under the control of the display control circuit. More specifically, by monitoring the actual driving parameters of the color wheel motor, when an image display abnormality problem occurs in the projection device due to a decrease in motor driving parameters, timely compensation of the driving parameters can be made, enabling the color wheel to rotate at the required frequency under the control of the display control circuit, ensuring normal image display, and extending the service life of the projection device.

[0124] like Figure 3 and Figure 8 As shown in the illustration, this application provides a projection device, which includes a light source 101. The light source 101 is configured to emit a monochromatic laser beam. For example, the light source 101 is configured to emit a blue laser beam.

[0125] The projection device also includes a color wheel 30, which is configured to emit multiple colors of laser light along different optical paths after being irradiated by a laser beam. For example, a blue laser beam can be processed by the color wheel 30 to output red, green, blue, and yellow laser light.

[0126] More specifically, the color wheel 30 includes a fluorescent color wheel 310 and a color filter wheel 320. The fluorescent color wheel 310 has color areas of different colors, and correspondingly, the color filter wheel 320 also has color areas of different colors. Monochromatic laser light passing through different areas of the fluorescent color wheel 310 produces beams of different colors, and after passing through the color filter wheel 320 for beam purification, it produces laser light of multiple colors. The working principle of the fluorescent color wheel 310 and the color filter wheel 320 can be referred to the above embodiment, and will not be repeated here.

[0127] The projection device also includes a light valve 108. The light valve 108 is configured to modulate the color beam emitted from the color wheel 30 and project an image beam to the projection lens 109. In some embodiments, the light valve 108 is specifically a DMD display chip.

[0128] The projection device also includes a projection lens 109, which is configured to image the incident laser beam.

[0129] The projection device also includes a display control circuit 10, which is configured to acquire a video period signal and the actual driving parameters of the color wheel motor, output a color wheel control signal based on the video period signal, and adjust the reference driving parameters based on the actual driving parameters.

[0130] The light valve 108 is used to modulate the color beam emitted by the color wheel 30. To ensure the projection effect, the color wheel 30 and the light valve 108 must be synchronized. The video periodic signal is used to control the synchronization of the color wheel 30 and the light valve 108. More specifically, the video periodic signal is used to control the rotation frequency of the color wheel 30. Therefore, after the display control circuit 10 receives the video periodic signal, it outputs a color wheel control signal based on the video periodic signal, causing the color wheel 30 to rotate at the required frequency.

[0131] In some embodiments, the video periodic signal includes multiple frames of video images and a field synchronization periodic signal Vsync. The display control circuit 10 receives the video periodic signal and decodes it to extract the field synchronization periodic signal Vsync to control the color wheel speed, and at the same time to control the synchronous display of the light valve 108.

[0132] In some embodiments, the target rotational speed of the color wheel 30 is an integer multiple of the field synchronization period signal Vsync. For example, if the field synchronization period signal Vsync is 60Hz, the target rotational speed of the color wheel 30 is 120Hz or 240Hz.

[0133] In this circuit, after the display control circuit 10 generates the color wheel control signal, the color wheel drive circuit 20 needs to convert the color wheel control signal into a color wheel drive signal based on the drive parameters of the color wheel motor. Typically, reference drive parameters are stored in both the display control circuit 10 and the color wheel drive circuit 20. When the color wheel drive circuit 20 generates the color wheel drive signal, it converts the color wheel control signal according to the pre-stored reference drive parameters. However, since the actual drive parameters of the color wheel motor change with temperature, if fixed drive parameters are used for control signal conversion, the color wheel motor will not rotate at the required frequency. Therefore, the display control circuit 10 also receives the actual drive parameters of the color wheel motor and adjusts the reference drive parameters according to them to match the actual drive parameters. The adjusted reference drive parameters are then sent to the color wheel drive circuit 20. By using the adjusted reference drive parameters to convert the color wheel control signal to obtain the color wheel drive signal, the color wheel motor can rotate at the required frequency.

[0134] In some embodiments, the projection device further includes a color wheel drive circuit 20, which is electrically connected to the display control circuit 10 and configured to receive a color wheel control signal and adjusted reference drive parameters, and generate a color wheel drive signal based on the color wheel control signal and the adjusted reference drive parameters.

[0135] In some embodiments, the projection device further includes a color wheel motor (not shown), which is fixedly connected to the color wheel 30 and electrically connected to the color wheel drive circuit 20. The color wheel motor is configured to receive a color wheel drive signal and drive the color wheel 30 to rotate based on the color wheel drive signal.

[0136] In the above technical solution, the color wheel drive circuit 20 generates a drive signal based on the control signal output by the display control circuit 10 and the reference drive parameters of the color wheel motor. Since the temperature affects the driving performance of the motor mainly by changing the drive parameters, if the color wheel drive circuit 20 still generates a drive signal based on the original reference drive parameters, the color wheel motor will not be able to rotate at the preset frequency. By adjusting the reference drive parameters according to the actual drive parameters, the color wheel drive circuit 20 generates a drive signal based on the adjusted reference drive parameters. In this way, the influence of temperature on motor performance can be adapted, and the motor speed can meet the required frequency.

[0137] In some embodiments, the display control circuit 10 is configured to:

[0138] When the actual driving parameters are greater than the reference driving parameters, the reference driving parameters are not adjusted.

[0139] When the actual driving parameters are less than or equal to the reference driving parameters, adjust the reference driving parameters.

[0140] Specifically, when the actual driving parameters are greater than the reference driving parameters (meaning the actual driving capability of the color wheel motor is greater than its expected driving capability), the color wheel motor can achieve the required driving performance, and therefore no adjustment of the reference driving parameters is needed. Conversely, when the actual driving parameters are less than or equal to the reference driving parameters (meaning the actual driving capability of the color wheel motor is less than its expected driving capability), the color wheel motor cannot achieve the required driving performance. In this case, when the color wheel driving signal generated based on the reference driving parameters drives the color wheel motor, the motor cannot rotate at the required frequency, and adjustment of the reference driving parameters is necessary.

[0141] In the above technical solution, adjusting the reference driving parameters only when the color wheel motor cannot achieve the required driving performance can reduce the data transmission of the display control circuit 10, improve the response performance of the projection device, and also reduce the power consumption of the device.

[0142] In some embodiments, the display control circuit 10 is configured to:

[0143] When the actual driving parameters are less than or equal to the reference driving parameters, reduce the reference driving parameters.

[0144] Specifically, when the actual driving parameters are less than or equal to the reference driving parameters, that is, when the actual driving capability of the color wheel motor is less than the expected driving capability of the color wheel motor, the expected driving capability of the color wheel motor can be reduced by decreasing the reference driving parameters, thereby enabling the color wheel motor to achieve the required driving performance.

[0145] In the above technical solution, by reducing the reference driving parameters, the expected driving capability of the color wheel motor is reduced, which enables the color wheel motor to achieve the required driving performance, thereby enabling the motor speed to meet the required frequency.

[0146] In some embodiments, the display control circuit 10 is configured to:

[0147] When the actual driving parameter is less than or equal to the reference driving parameter, reduce the reference driving parameter so that the reference driving parameter is less than the actual driving parameter.

[0148] Specifically, when the actual driving parameters are less than or equal to the reference driving parameters, the reference driving parameters are reduced to make them less than the actual driving parameters. As a result, the actual driving capability of the color wheel motor is greater than the expected driving capability of the color wheel motor. This allows the color wheel motor to achieve the required driving performance, thereby enabling the motor speed to meet the required frequency.

[0149] In some embodiments, such as Figure 9 As shown, the display control circuit 10 includes:

[0150] The adjustment circuit 110, electrically connected to the color wheel motor, is configured to acquire the actual driving parameters of the color wheel motor and generate an adjustment signal based on the actual driving parameters and reference driving parameters.

[0151] The control circuit 120, electrically connected to the adjustment circuit 110 and the color wheel drive circuit 20, is configured to adjust the reference drive parameters according to the adjustment signal and send the adjusted reference drive parameters to the color wheel drive circuit 20.

[0152] The adjustment signal indicates whether to adjust the reference drive parameter. When the actual drive parameter is less than or equal to the reference drive parameter, the generated adjustment signal level is the first level, indicating that the reference drive parameter needs to be adjusted. When the actual drive parameter is greater than the reference drive parameter, the generated adjustment signal level is the second level, indicating that the reference drive parameter does not need to be adjusted.

[0153] After receiving the adjustment signal, the control circuit 120 determines whether the reference driving parameters need to be adjusted by reading the level of the adjustment signal. After adjusting the reference driving parameters, the adjusted reference driving parameters are sent to the color wheel drive circuit 20.

[0154] In the above technical solution, the display control circuit 10 includes an adjustment circuit 110 and a control circuit 120. The adjustment circuit 110 generates an adjustment signal based on the actual driving parameters and reference driving parameters of the color wheel motor. Thus, the control circuit 120 can determine whether the reference driving parameters need to be adjusted by acquiring the adjustment signal, and send the adjusted reference driving parameters to the color wheel drive circuit 20, so that the color wheel drive circuit 20 can generate a color wheel drive signal based on the adjusted reference driving parameters. When the motor is driven by the color wheel drive signal, the motor speed meets the required frequency.

[0155] In some embodiments, continue to refer to Figure 9 The regulating circuit 110 includes:

[0156] The converter 111, electrically connected to the neutral point of the windings of the color wheel motor, is configured to acquire the back electromotive force (EMF) of the color wheel motor and generate the actual drive parameters of the color wheel motor based on the back EMF.

[0157] The comparator circuit 112 has a first input terminal connected to the output terminal of the conversion device 111, and a second input terminal receiving reference driving parameters. It is configured to generate an adjustment signal based on the actual driving parameters and the reference driving parameters.

[0158] The conversion device 111, electrically connected to the neutral point of the winding of the color wheel motor, obtains the back electromotive force (EMF) of the color wheel motor and converts it into actual driving parameters based on the conversion relationship between the back EMF and the driving parameters. The comparator circuit 112 compares the actual driving parameters with the reference driving parameters and outputs an adjustment signal.

[0159] In some embodiments, the adjustment signal is high when the actual drive parameter is greater than the reference drive parameter. The adjustment signal is low when the actual drive parameter is less than or equal to the reference drive parameter. A high level indicates that no adjustment of the reference drive parameter is required. A low level indicates that adjustment of the reference drive parameter is required.

[0160] In the above technical solution, the adjustment circuit 110 includes a conversion device 111 and a comparison circuit 112. The conversion device 111 acquires the back electromotive force of the color wheel motor and generates actual driving parameters based on the back electromotive force, thus accurately obtaining the actual driving parameters. The comparison circuit 112 compares the magnitudes of the actual driving parameters and the reference driving parameters to generate an adjustment signal. By acquiring the level of the adjustment signal, it can be determined whether the reference driving parameters need to be adjusted.

[0161] In some embodiments, continue to refer to Figure 9 The comparator circuit 112 includes:

[0162] Operational amplifier OP1 has its first input terminal electrically connected to the output terminal of conversion device 111, and its second input terminal receiving reference drive parameters, and is configured to output an adjustment signal from the output terminal.

[0163] The feedback resistor R3 has its first end electrically connected to the second input terminal of the operational amplifier OP1, and its second end electrically connected to the output terminal of the operational amplifier.

[0164] In the above technical solution, by connecting a feedback resistor R3 between the second input terminal and the output terminal of the operational amplifier OP1, the operational amplifier OP1 can be made to operate in shaping circuit mode. In this way, the operational amplifier can output a high level or a low level according to the difference between the actual driving parameters and the reference driving parameters.

[0165] In some embodiments, the driving parameters specifically include the torque constant KT, and the conversion device 111 is configured as follows:

[0166] Calculate the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor.

[0167] The actual drive parameters are determined based on the ratio between the back electromotive force of the color wheel motor and the speed of the color wheel motor, and a preset coefficient.

[0168] In some embodiments, the actual drive parameters are determined by multiplying the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor with a preset coefficient.

[0169] Among them, the preset coefficient is In other words, the conversion relationship between back electromotive force and driving parameters satisfies the following formula:

[0170]

[0171] Where KT represents the driving parameters, in Nm / A, v BEMF_rms is the back electromotive force voltage, in volts; N is the motor speed, in Hz.

[0172] In the above technical solution, the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor is calculated, and the actual driving parameters are determined based on the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor and a preset coefficient, thus realizing the conversion between the back electromotive force and the actual driving parameters.

[0173] In some embodiments, the control circuit is configured to acquire a video period signal and output a color indication signal, a color wheel control signal, and a light valve control signal based on the video period signal.

[0174] In some embodiments, the control circuit is a separate display control chip, and the adjustment circuit is another custom chip, both located on the same substrate. The display control circuit function can be implemented using existing general-purpose display control chips, or a custom chip can be directly customized according to the function of the display control circuit. Similarly, the adjustment circuit function can be implemented using existing general-purpose chips, or a custom chip can be directly customized according to the function of the adjustment circuit.

[0175] In some embodiments, the control circuit is a separate display control chip, the conversion device and the operational amplifier are separate custom chips, and the conversion device, operational amplifier, feedback resistor and display control chip are located on the same substrate.

[0176] In some embodiments, the control circuit and the adjustment circuit are integrated into a single control chip. The functions of the control circuit and the adjustment circuit can be implemented using existing general-purpose display control chips.

[0177] In some embodiments, continue to refer to Figure 9 The color wheel drive circuit 20 includes:

[0178] The excitation control circuit 210, which is electrically connected to the display control circuit 10, is configured to generate a bridge arm control signal based on the color wheel control signal and the adjusted reference drive parameters.

[0179] The bridge arm switching circuit 220 is electrically connected to the excitation control circuit 210 at its control terminal, receives DC power at its DC terminal, and is electrically connected to the electrical terminal of the color wheel motor at its AC terminal. It is configured to provide excitation voltage to the electrical terminal of the color wheel motor based on the bridge arm control signal.

[0180] The excitation control circuit 210 generates a bridge arm control signal, which controls the switching transistors in the bridge arm conversion circuit 220 to turn on or off, thereby controlling the output voltage of the bridge arm conversion circuit 220. The magnitude of the color wheel control signal controls the output voltage of the bridge arm conversion circuit 220. In some embodiments, when the color wheel control signal is a voltage signal, the magnitude of the voltage signal controls the output voltage of the bridge arm conversion circuit 220. In other embodiments, when the color wheel control signal is a current signal, the magnitude of the current signal controls the output voltage of the bridge arm conversion circuit 220. In some embodiments, when the color wheel control signal is a PWM signal, the duty cycle of the PWM controls the output voltage of the bridge arm conversion circuit 220.

[0181] In some embodiments, the mapping relationship between the color wheel control signal and the bridge arm control signal is different under different reference driving parameters. By obtaining the mapping relationship under the corresponding reference driving parameters, the color wheel control signal can be converted into a bridge arm control signal.

[0182] In the above technical solution, the color wheel drive circuit 20 includes an excitation control circuit 210 and a bridge arm conversion circuit 220. The excitation control circuit 210 converts the color wheel control signal into a bridge arm control signal based on the adjusted reference drive parameters. The bridge arm control signal controls the bridge arm conversion circuit 220 to output an excitation voltage to the color wheel motor, thereby realizing the drive of the color wheel motor.

[0183] In some embodiments, continue to refer to Figure 9 The color wheel drive circuit 20 also includes:

[0184] Feedback circuit 230, electrically connected to color wheel motor and excitation control circuit 210, is configured to acquire the actual speed Sm of color wheel motor, generate a speed difference SEr based on the actual speed Sm and the target speed SRef of color wheel motor, generate a difference control signal VEr based on the speed difference SEr, and output the adjustment voltage to excitation control circuit 210.

[0185] The feedback circuit 230, connected to the color wheel motor, can obtain the actual speed Sm of the color wheel motor, calculate the speed difference SEr between the actual speed Sm and the target speed SRef of the color wheel motor, generate a difference control signal VEr based on the speed difference SEr, and output the difference control signal VEr to the excitation control circuit 210. In this way, the excitation control circuit 210 can adjust the output bridge arm control signal based on the voltage adjustment to realize the feedback control of the color wheel motor drive.

[0186] In some embodiments, continue to refer to Figure 9 The feedback circuit 230 includes:

[0187] The speed operational amplifier 231 has its first input terminal electrically connected to the color wheel motor, its second input terminal receiving the target speed SRef, and is configured to output the speed difference SEr of the color wheel motor.

[0188] The speed regulation circuit 232 is electrically connected to the output of the speed operational amplifier 231 and is configured to generate a voltage signal Vo based on the speed difference SEr of the color wheel motor.

[0189] The speed control circuit 233 has its first input terminal electrically connected to the speed adjustment circuit 232, and its second input terminal receiving the reference voltage Vs. It is configured to generate a difference control signal VEr based on the voltage signal Vo and the reference voltage Vs, and send the difference control signal VEr to the excitation control circuit 210.

[0190] The speed operational amplifier 231 has its first input connected to the color wheel motor, receiving the actual speed Sm of the motor. Its second input receives the target speed SRef of the motor, and its output outputs the speed difference SEr of the color wheel motor. The speed regulation circuit 232 is electrically connected to the output of the speed operational amplifier 231. The speed regulation circuit 232 converts the speed difference SEr of the color wheel motor into a voltage signal Vo. The speed control circuit 233 has its first input electrically connected to the speed regulation circuit 232, receiving the voltage signal Vo, and its second input receiving a reference voltage Vs. The speed control circuit 233 generates a difference control signal VEr based on the voltage signal Vo and the reference voltage Vs, and sends the difference control signal VEr to the excitation control circuit 210. Thus, the excitation control circuit 210 can adjust the output bridge arm control signal based on the difference control signal VEr, achieving feedback control of the color wheel motor drive.

[0191] In the above technical solution, the feedback circuit 230 includes a speed operational amplifier 231, a speed regulation circuit 232, and a speed control circuit 233. The operational amplifier and the speed regulation circuit 232 convert the speed into voltage for control. The speed control circuit 233 generates a difference control signal VEr based on the voltage signal Vo and the reference voltage Vs, and sends the difference control signal VEr to the excitation control circuit 210. In this way, the excitation control circuit 210 can adjust the output bridge arm control signal based on the voltage adjustment to realize the feedback control of the color wheel motor drive.

[0192] In some embodiments, the speed control circuit 233 includes a voltage operational amplifier OP2 and a sampling resistor Rs. The positive terminal of the voltage operational amplifier OP2 is connected to the output terminal of the speed regulator to receive the voltage signal Vo. The negative terminal of the voltage operational amplifier OP2 is connected to the first terminal of the sampling resistor Rs, which is connected to the negative power supply terminal of the bridge arm switching circuit 220. The second terminal of the sampling resistor Rs is grounded. The reference voltage Vs at the negative terminal of the voltage operational amplifier OP2 is Is × Rs. Where Is is the current flowing through the motor during stable motor rotation, and Rs is the sampling resistor.

[0193] When the laser light source 101 excites the yellow and green phosphors on the phosphor color wheel 310, it generates a lot of heat. The heat is transferred through the phosphor, the substrate disk, and the adhesive to the rotor (magnet) of the phosphor color wheel motor. When the heat causes the magnet of the phosphor color wheel motor to exceed the temperature specification for a long time, the magnetic flux of the magnet will decrease. The decrease in magnetic flux will cause the driving parameters of the motor to decrease. When the driving parameters decrease to a certain extent, the driving parameters of the phosphor color wheel 310 will not match those of the color wheel 30, resulting in a decrease in the rotation speed of the color wheel 30. As a result, the two color wheels 30 may not reach the preset color boundary at the same time, that is, the two color wheels 30 are misaligned, ultimately resulting in distorted image colors and the machine being unable to view the image normally.

[0194] Furthermore, since the color filter wheel 320 mainly purifies the light output from the fluorescent color wheel 310, its working principle is to transmit light, unlike the fluorescent powder wheel which reflects laser light. Therefore, the color filter wheel 320 generates very little heat when it is working, and there is no problem of the motor corresponding to the color filter wheel 320 overheating.

[0195] In some embodiments, such as Figure 10 and Figure 11 As shown, the color wheel 30 includes a fluorescent color wheel 310, and the display control circuit 10 is configured to adjust the reference driving parameters of the fluorescent color wheel 310 based on the actual driving parameters of the fluorescent color wheel 310.

[0196] The color wheel drive circuit 20 includes a fluorescent color wheel drive circuit 31, which is configured to receive a fluorescent color wheel control signal and adjusted reference drive parameters, and generate a fluorescent color wheel drive signal based on the color wheel control signal and the adjusted reference drive parameters.

[0197] In some embodiments, continue to refer to Figure 10 and Figure 12The projection device also includes a color filter wheel drive circuit 32. The color filter wheel drive circuit 32 is connected to the display control circuit 10 and is configured to receive the color filter wheel control signal output by the display control circuit 10, and generate a color filter wheel drive signal based on the color filter wheel control signal. The color filter wheel drive signal is used to drive the color filter wheel 320 to rotate.

[0198] In some embodiments, the color filter wheel drive circuit 32 converts the color filter wheel control signal according to the reference drive parameters of the color filter wheel motor stored locally, and generates a color filter wheel drive signal.

[0199] In some embodiments, continue to refer to Figure 10 and Figure 12 The projection device also includes a color filter wheel 320, which is connected to the color filter wheel drive circuit 32 and is configured to receive the color filter wheel drive signal and rotate under the drive of the color filter wheel drive signal.

[0200] In some embodiments, continue to refer to Figure 10 and Figure 11 A first mark is provided on the fluorescent color wheel 310. The projection device also includes a first speed sensor 41, which is located near the substrate disk of the fluorescent color wheel 310. Thus, when the first mark passes the first speed sensor 41, a pulse signal is generated. The pulse signal is used to characterize the actual speed of the fluorescent color wheel 310.

[0201] In some embodiments, continue to refer to Figure 10 and Figure 11 The first speed sensor 41 is connected to the display control circuit 10 via electronic wires, thereby transmitting the periodic signal to the display control circuit 10.

[0202] In some embodiments, continue to refer to Figure 10 and Figure 11Because stray light near the first speed sensor 41 and the surface of the fluorescent color wheel 310 are not absolutely black or absolutely white, the high level output by the first speed sensor 41 is not the low level 0V, and the low level output by the first speed sensor 41 is not the high level 3.3V. Therefore, a first shaping circuit 51 is set between the display control circuit 10 and the first speed sensor 41. The first shaping circuit 51 shapes the high and low levels output by the sensor into a low level 0V and a high level 3.3V. Here, 3.3V is used as an example only. The output terminal of the first speed sensor 41 is connected to the first input terminal of the first shaping circuit 51. The first input terminal of the first shaping circuit 51 receives a pulse signal, and the second input terminal of the first shaping circuit 51 receives a shaping voltage. The first shaping circuit 51 is configured to shape the pulse signal output by the first speed sensor 41 and output the shaped pulse signal to the display control circuit 10. The display control circuit 10 adjusts the control signal output to the fluorescent color wheel drive circuit 31 based on the shaped pulse signal.

[0203] In some embodiments, continue to refer to Figure 10 and Figure 12 A second mark is provided on the color filter wheel 320. The projection device also includes a second speed sensor 42, which is located near the substrate disk of the color filter wheel 320. When the second mark passes the second speed sensor 42, a pulse signal is generated. The pulse signal is used to characterize the actual speed of the color filter wheel 320.

[0204] In some embodiments, continue to refer to Figure 10 and Figure 12 Because stray light near the second speed sensor 42 and the surface of the fluorescent color wheel 310 are not absolutely black or absolutely white, the high level output by the second speed sensor 42 is not the low level 0V, and the low level output by the second speed sensor 42 is not the high level 3.3V. Here, 3.3V is used as an example only. Therefore, a second shaping circuit 52 is provided between the display control circuit 10 and the second speed sensor 42. The second shaping circuit 52 shapes the high and low levels output by the sensor into a low level 0V and a high level 3.3V. The output terminal of the second speed sensor 42 is connected to the first input terminal of the second shaping circuit 52. The first input terminal of the second shaping circuit 52 receives pulse signals, and the second input terminal receives shaping voltage. The second shaping circuit 52 is configured to shape the pulse signals output by the second speed sensor 42 and output the shaped pulse signals to the display control circuit 10. The display control circuit 10 adjusts the color wheel control signal output to the color wheel drive circuit 32 based on the shaped pulse signals.

[0205] In some embodiments, both the first shaping circuit 51 and the second shaping circuit 52 are comparators. The shaping voltage can be set to 1.7V. When the voltage of the pulse signal received by the comparator is less than 1.7V, the output is low. When the voltage of the pulse signal received by the comparator is greater than 1.7V, the output is high.

[0206] The fluorescent color wheel 310 uses a first indicator to inform the display control circuit 10 of the starting order of each color, so that the display control circuit 10 can correctly process the image and display the vibrant colors according to the front-end signal. Furthermore, the fluorescent color wheel 310 and the color filter wheel 320 in the system need to be completely synchronized, meaning they have corresponding color zones and rotate at the same speed, ensuring that the fluorescent color wheel 310 and the color filter wheel 320 maintain the same rotational frequency.

[0207] Since the rotational stability of the fluorescent color wheel 310 and the color filter wheel 320 determines the normal display of image colors, the display control circuit 10 monitors them in real time. The display control circuit 10 monitors the periodic signals output by the first speed sensor and the second speed sensor in real time to determine the rotational speed of the fluorescent color wheel 310 and the color filter wheel 320.

[0208] Continue to refer to Figure 10 The projection device includes a multimedia chip 70. The display control circuit 10 receives the video cycle signal from the multimedia chip 70. The display of each frame of video image in the video cycle signal is synchronized according to the field synchronization cycle signal Vsync. The video cycle signal of the multimedia chip 70 contains the field synchronization cycle signal Vsync. The display control circuit 10 receives the video cycle signal and decodes it. The field synchronization cycle signal Vsync is then used to control the rotation speed of the phosphor wheel 310 and the color filter wheel 320, and is also used to control the synchronous display of the DMD display chip.

[0209] For example, the video cycle signal sent by the multimedia chip 70 to the display control circuit 10 is 3840×2160@60Hz. 3840 indicates that one frame of the image has 3840 columns, 2160 indicates that one frame of the image has 2160 rows, and 60Hz indicates that 60 frames of the image are displayed per second, that is, the field synchronization cycle signal Vsync is 60Hz. The rotation speed of the light color wheel 30 and the color filter wheel 320 is 120Hz, that is, 120 revolutions per second. At the same time, the DMD display chip refreshes the display according to integer multiples of 60Hz.

[0210] In some embodiments, the multimedia chip 70 is a system-on-a-chip (SOC).

[0211] In some embodiments, continue to refer to Figure 10The projection device also includes a laser driving circuit 80, which is connected to the display control circuit 10 and to the laser. The laser driving circuit 80 is configured to acquire the laser control signal output by the display control circuit 10 and generate a laser driving signal based on the laser control signal, and the laser emits light based on the laser driving signal.

[0212] In some embodiments, continue to refer to Figure 10 The projection device also includes an enable control unit 60, and the display control circuit 10 is also connected to the enable control unit 60. The enable control unit 60 is connected to the laser drive circuit 80. The display control circuit 10 is also configured to output an enable control signal to the enable control unit 60. The enable control unit 60 is configured to generate an enable signal based on the enable control signal. The laser drive circuit 80 is configured to generate a laser drive signal based on the laser control signal upon receiving the enable signal.

[0213] In some embodiments, continue to refer to Figure 10 The enable control unit 60 is connected to the output terminal of the first shaping circuit 51. The enable control unit 60 is configured to generate an enable signal for the laser driving circuit 80 based on the shaped pulse signal. The laser driving circuit 80 is configured to generate a laser driving signal based on the laser control signal upon receiving the enable signal.

[0214] In some embodiments, continue to refer to Figure 10 The enable control unit 60 is connected to the output terminal of the second shaping circuit 52. The enable control unit 60 is configured to generate an enable signal for the laser driving circuit 80 based on the shaped pulse signal. The laser driving circuit 80 is configured to generate a laser driving signal based on the laser control signal upon receiving the enable signal.

[0215] like Figure 13 As shown, in some embodiments, the multimedia chip 70 is also connected to external buttons to receive input information from the user via the buttons.

[0216] In some embodiments, the multimedia chip 70 is also connected to an external infrared remote control to receive input information from the user via the infrared remote control.

[0217] In some embodiments, the multimedia chip 70 is also connected to an external far-field voice input device to receive input information from the user via far-field voice input.

[0218] In some embodiments, the multimedia chip 70 is also connected to an external HDMI interface to receive input signals input through the HDMI interface.

[0219] In some embodiments, the multimedia chip 70 is also connected to an external USB interface to receive input signals input through the USB interface.

[0220] In some embodiments, the multimedia chip 70 is also connected to an external speaker to output information to the speaker.

[0221] In some embodiments, the multimedia chip 70 is also connected to an optical fiber to output information to the outside world.

[0222] In some embodiments, the multimedia chip 70 is also connected to an RJ45 network port to interact with external devices.

[0223] In some embodiments, the multimedia chip 70 is also connected to a WIFI module and / or a Bluetooth module to interact with external devices.

[0224] Continue to refer to Figures 10 to 12 After the projection device is powered on, the display control circuit 10 sends startup parameters to the phosphor wheel drive circuit and the color filter wheel drive circuit 22. These startup parameters include the target rotation speed SRef of the phosphor wheel motor and the target rotation speed of the color filter wheel 320 motor. The startup parameters also include reference drive parameters for the phosphor wheel 310.

[0225] More specifically, the display control circuit 10 has a data input pin DIN, a data output pin DOUT, a clock pin CLK, and a chip select pin CS. When the chip select pin CS is high, the display control circuit 10 is in an idle state and does not communicate with the outside. When the chip select pin CS is low, the display control circuit 10 is in an active state and communicates with the outside. The data input pin DIN, the data output pin DOUT, and the clock pin CLK are used to realize communication between the display control circuit 10 and the color wheel drive circuit. For example, the start parameters are output to the color wheel drive circuit through the data input pin DIN.

[0226] The display control circuit 10 is provided with at least two data input pins DIN, a data output pin DOUT, and a clock pin CLK, which are respectively labeled as data input pin DIN1, data output pin DOUT1, and clock pin CLK1, as well as data input pin DIN2, data output pin DOUT2, and clock pin CLK2.

[0227] Data input pin DIN1, data output pin DOUT1, and clock pin CLK1 are used to realize communication between display control circuit 10 and phosphor color wheel drive circuit. Data input pin DIN2, data output pin DOUT2, and clock pin CLK2 are used to realize communication between display control circuit 10 and color filter drive circuit.

[0228] The fluorescent color wheel drive circuit 21 includes a speed operational amplifier 231, a speed regulation circuit 232, and a speed control circuit 233. The speed operational amplifier 231 compares the actual speed Sm of the fluorescent color wheel motor with the target speed SRef of the fluorescent color wheel motor to obtain the speed difference SEr of the fluorescent color wheel motor. The speed operational amplifier 231 outputs the speed difference SEr of the fluorescent color wheel motor to the speed regulation circuit 232, and the speed regulation circuit 232 adjusts the speed difference SEr of the fluorescent color wheel motor to output a voltage signal V0.

[0229] More specifically, if the actual rotational speed Sm of the fluorescent color wheel motor is less than the target rotational speed SRef, the generated voltage signal V0 is used to increase the rotational speed of the fluorescent color wheel motor. If the actual rotational speed Sm of the fluorescent color wheel motor is greater than the target rotational speed SRef, the generated voltage signal V0 is used to decrease the rotational speed of the fluorescent color wheel motor. The speed adjustment circuit 232 stops adjusting when the actual rotational speed Sm of the fluorescent color wheel motor equals the target rotational speed SRef.

[0230] The speed regulation circuit 232 transmits the voltage signal V0 to the first input terminal of the speed control circuit 233. The second input terminal of the speed control circuit 233 receives the reference voltage Vs. The output terminal of the speed control circuit 233 generates a difference control signal based on the voltage signal V0 and the reference voltage Vs. The difference control signal is sent to the excitation control circuit 210 to adjust the duty cycle of the bridge arm control signal.

[0231] The speed control circuit 233 includes a voltage operational amplifier OP2 and a sampling resistor Rs. The positive terminal of the voltage operational amplifier OP2 is connected to the output terminal of the speed regulator to receive the voltage signal V0. The negative terminal of the voltage operational amplifier OP2 is connected to the first terminal of the sampling resistor Rs, which is connected to the negative power supply terminal of the bridge arm conversion circuit 220. The second terminal of the sampling resistor Rs is grounded. The reference voltage Vs at the negative terminal of the voltage operational amplifier OP2 is Is × Rs. Where Is is the current flowing through the motor during stable motor rotation, and Rs is the sampling resistor.

[0232] The reference voltage Vs at the negative terminal of the voltage operational amplifier OP2 is the voltage generated during the stable rotation of the motor. As long as the input voltage V0 and the voltage Vs generated during stable motor rotation are not equal, the motor speed is continuously adjusted by using the differential control signal VER to regulate the duty cycle of the bridge arm control signal. When V0 > Vs, the differential control signal VER increases the duty cycle of the bridge arm control signal; for example, increasing the duty cycle of the lower bridge arm control signal increases the on-time of the MOSFET in the lower bridge arm, thus accelerating the motor. When V0 < Vs, the differential control signal VER decreases the duty cycle of the bridge arm control signal; for example, decreasing the duty cycle of the lower bridge arm control signal decreases the on-time of the MOSFET in the lower bridge arm, thus decelerating the motor until V0 = Vs, i.e., the actual speed Sm equals the target speed SRef.

[0233] The fluorescent color wheel drive circuit 21 includes a speed operational amplifier 231, a speed regulation circuit 232, and a speed control circuit 233, which ensure that the actual motor speed Sm equals the target speed SRef, allowing the motor to operate stably at the target speed SRef. The speed regulation circuit 232 and the speed control circuit 233 correlate the motor's speed, voltage, and current, thereby guaranteeing stable motor operation at the target speed SRef.

[0234] Additionally, please continue to refer to Figure 10 The display controller detects the actual stable operating speed CW1 of the fluorescent color wheel motor through the first speed sensor 40. Then, it compares the actual speed CW1 with the target speed SRef, which is an integer multiple of the field synchronization period signal Vsync. For example, if the field synchronization period signal Vsync is 60Hz, the target speed SRef is 120Hz or 240Hz. When the actual speed CW1 and the target speed SRef are not equal, the fluorescent color wheel control signal is adjusted.

[0235] In some embodiments, the phosphor color wheel control signal is a PWM signal. The display control circuit has a PWM signal pin, which is connected to the phosphor color wheel drive circuit. The color wheel control signal is output through the PWM signal pin. A filter circuit is provided on the PWM signal pin of the display control circuit. The filter circuit includes a filter resistor R and a filter capacitor C.

[0236] When the actual speed CW1 is less than the target speed SRef, the duty cycle of the color wheel control signal is increased to accelerate the motor; conversely, the duty cycle of the color wheel control signal is decreased to decelerate the motor. This process continues until the actual speed CW1 equals the target speed Sref, at which point the entire speed adjustment process ends and the motor runs stably at the target speed.

[0237] The speed control of the color filter wheel motor by the color filter wheel drive circuit 22 is the same as the speed control of the fluorescent color wheel motor by the fluorescent color wheel drive circuit 21, and will not be described again here. The speed control of the color filter wheel motor by the display control circuit is the same as the speed control of the fluorescent color wheel motor by the display control circuit, and will not be described again here.

[0238] The fluorescent color wheel motor has three phases: U, V, and W. These three phases are connected together and called the neutral point M. During motor rotation, the back electromotive force (BEMF) voltage can be obtained by detecting the neutral point voltage. The higher the rotational speed, the larger the BEMF voltage, and vice versa.

[0239] The conversion device 111 converts the back electromotive force into a torque constant, and the conversion formula is as follows:

[0240]

[0241] Where KT is the torque constant, with units of Nm / A, v BEMF_rms is the back electromotive force voltage, in volts; N is the motor speed, in Hz.

[0242] The comparison circuit 112 compares the reference torque constant KTref and the actual torque constant KTm sent by the display control circuit 10. When the reference torque constant KTref > the actual torque constant KTm, it outputs a high level; when the reference torque constant KTref < the actual torque constant KTm, it outputs a low level. The adjustment signal KTout is input to the display control circuit 10.

[0243] When the display control circuit 10 receives a low-level adjustment signal KTout, it indicates that the actual torque constant meets the motor requirements. When the display control circuit 10 receives a high-level adjustment signal KTout, it resets the torque constant of its internal phosphor wheel and outputs the adjusted driving torque constant of the phosphor wheel motor to the phosphor wheel drive circuit through the chip select signal pin CS, the clock signal pin CLK1, and the data input pin DIN1. In some embodiments, after restarting the projection device, the display control circuit outputs the adjusted driving torque constant of the phosphor wheel motor to the phosphor wheel drive circuit.

[0244] More specifically, the display control circuit reduces the reference torque constant to ensure that the reference torque constant is less than the measured torque constant, typically about 0.9 times the measured torque constant.

[0245] By setting up the conversion device 111 and the comparison circuit 112, when the value of the fluorescent color wheel motor drive parameter drops, the drive parameter is promptly compensated and adjusted, thus extending the service life of the projection device.

[0246] Some embodiments of this application provide a driving method for a projection device, the projection device including:

[0247] Light source 101 is configured to emit a monochromatic laser beam;

[0248] The color wheel 30 is configured to emit lasers of multiple colors along different optical paths after being irradiated by a laser beam;

[0249] The light valve 108 is configured to modulate the color beam emitted by the color wheel 30 and emit an image beam to the projection lens 109.

[0250] The projection lens 109 is configured to image the incident laser beam;

[0251] like Figure 14 As shown, the driving method for the projection device specifically includes the following steps:

[0252] S101. Acquire the video period signal and the actual drive parameters of the color wheel motor;

[0253] S102. Output color wheel control signal based on video periodic signal, and adjust reference driving parameters based on actual driving parameters;

[0254] Among them, the color wheel 30 control signal and the adjusted reference drive parameters are used to generate the color wheel 30 drive signal, which is used to drive the color wheel 30 to rotate.

[0255] In some embodiments, adjusting the reference driving parameters based on the actual driving parameters specifically includes:

[0256] When the actual driving parameters are greater than the reference driving parameters, the reference driving parameters are not adjusted.

[0257] When the actual driving parameters are less than or equal to the reference driving parameters, adjust the reference driving parameters.

[0258] In some embodiments, when the actual driving parameter is less than or equal to the reference driving parameter, adjusting the reference driving parameter specifically includes:

[0259] When the actual driving parameters are less than or equal to the reference driving parameters, reduce the reference driving parameters.

[0260] In some embodiments, when the actual driving parameter is less than or equal to the reference driving parameter, the reference driving parameter is reduced, specifically including:

[0261] When the actual driving parameter is less than or equal to the reference driving parameter, reduce the reference driving parameter so that the reference driving parameter is less than the actual driving parameter.

[0262] In some embodiments, obtaining the actual driving parameters of the color wheel 30 motor specifically includes:

[0263] Obtain the back electromotive force of the color wheel 30 motor, and generate the actual driving parameters of the color wheel 30 motor based on the back electromotive force of the color wheel 30 motor.

[0264] In some embodiments, the actual driving parameters of the color wheel 30 motor are generated based on the back electromotive force of the color wheel 30 motor, specifically including:

[0265] Calculate the ratio between the back electromotive force of the color wheel 30 motor and the rotational speed of the color wheel 30 motor;

[0266] The actual drive parameters are determined based on the ratio between the back electromotive force of the color wheel 30 motor and the speed of the color wheel 30 motor, and a preset coefficient.

[0267] like Figure 15 As shown, some embodiments of this application also provide a driving method for a projection device, which specifically includes the following steps:

[0268] S201. Acquire the video periodic signal and the actual drive parameters of the color wheel motor.

[0269] S202. Determine whether the actual driving parameters of the color wheel motor are greater than the reference driving parameters. If yes, proceed to S203; otherwise, proceed to S204.

[0270] S203, Keep the reference drive parameters unchanged.

[0271] S204. Adjust the reference drive parameters based on the actual drive parameters.

[0272] The driving method for the projection device provided in this application embodiment has a similar implementation principle and technical effect to the projection device in the above embodiment, and will not be repeated here.

[0273] This application also provides a computer-readable storage medium, which may include various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk. Specifically, the computer-readable storage medium stores computer-readable instructions, which are used in the methods described in the above embodiments.

[0274] This application also provides a program product including execution instructions stored in a readable storage medium. At least one control module of the projection device can read the execution instructions from the readable storage medium, and the at least one control module executes the execution instructions to cause the projection device to implement the driving methods of the projection device provided in the various embodiments described above.

[0275] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0276] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A projection device, characterized in that, The projection device includes: The light source is configured to emit a monochromatic laser beam; The color wheel is configured to emit lasers of multiple colors along different optical paths after being irradiated by the laser beam; A light valve is configured to modulate the colored light beam emitted by the color wheel and project an image beam to the projection lens; The projection lens is configured to image the incident laser beam. The projection device is characterized in that it further includes: The display control circuit is configured to acquire a video cycle signal and acquire the actual driving parameters of the color wheel motor, output a color wheel control signal based on the video cycle signal, and adjust the reference driving parameters based on the actual driving parameters. A color wheel drive circuit, electrically connected to the display control circuit, is configured to receive the color wheel control signal and adjusted reference drive parameters, and generate a color wheel drive signal based on the color wheel control signal and adjusted reference drive parameters; A color wheel motor is fixedly connected to the color wheel and electrically connected to the color wheel drive circuit. It is configured to receive the color wheel drive signal and drive the color wheel to rotate based on the color wheel drive signal.

2. The projection device according to claim 1, characterized in that, The display control circuit is configured as follows: When the actual driving parameter is greater than the reference driving parameter, the reference driving parameter is not adjusted; When the actual driving parameter is less than or equal to the reference driving parameter, the reference driving parameter is adjusted.

3. The projection device according to claim 2, characterized in that, The display control circuit is configured as follows: When the actual driving parameter is less than or equal to the reference driving parameter, the reference driving parameter is reduced.

4. The projection device according to claim 3, characterized in that, The display control circuit is configured as follows: When the actual driving parameter is less than or equal to the reference driving parameter, the reference driving parameter is reduced so that the reference driving parameter is less than the actual driving parameter.

5. The projection device according to any one of claims 1 to 4, characterized in that, The display control circuit includes: An adjustment circuit, electrically connected to the color wheel motor, is configured to acquire the actual driving parameters of the color wheel motor and generate an adjustment signal based on the actual driving parameters and reference driving parameters. The control circuit, electrically connected to the adjustment circuit and the color wheel drive circuit, is configured to adjust the reference drive parameters according to the adjustment signal and send the adjusted reference drive parameters to the color wheel drive circuit.

6. The projection device according to claim 5, characterized in that, The regulating circuit includes: A conversion device, electrically connected to the neutral point of the winding of the color wheel motor, is configured to acquire the back electromotive force of the color wheel motor and generate the actual driving parameters of the color wheel motor based on the back electromotive force of the color wheel motor. The comparator circuit has a first input terminal connected to the output terminal of the conversion device, and a second input terminal receiving the reference driving parameters, and is configured to generate the adjustment signal based on the actual driving parameters and the reference driving parameters.

7. The projection device according to claim 6, characterized in that, The comparison circuit includes: An operational amplifier, with its first input terminal electrically connected to the output terminal of the conversion device and its second input terminal receiving the reference driving parameters, is configured to output the adjustment signal from its output terminal. The feedback resistor has its first end electrically connected to the second input terminal of the operational amplifier, and its second end electrically connected to the output terminal of the operational amplifier.

8. The projection device according to claim 6, characterized in that, The switching device is configured to: Calculate the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor; The actual driving parameters are determined based on the ratio between the back electromotive force of the color wheel motor and the rotational speed of the color wheel motor, and a preset coefficient.

9. The projection device according to any one of claims 1 to 4, characterized in that, The color wheel includes a fluorescent color wheel, and the display control circuit is configured to adjust the reference driving parameters of the fluorescent color wheel based on the actual driving parameters of the fluorescent color wheel; The color wheel driving circuit includes a fluorescent color wheel driving circuit, which is configured to receive the color wheel control signal and adjusted reference driving parameters, and generate a color wheel driving signal based on the color wheel control signal and the adjusted reference driving parameters.

10. A driving method for a projection device, characterized in that, The projection device includes: The light source is configured to emit a monochromatic laser beam; The color wheel is configured to emit lasers of multiple colors along different optical paths after being irradiated by the laser beam; A light valve is configured to modulate the colored light beam emitted by the color wheel and project an image beam to the projection lens; The projection lens is configured to image the incident laser beam. The driving method is characterized by comprising: Acquire the video period signal and the actual driving parameters of the color wheel motor, output the color wheel control signal based on the video period signal, and adjust the reference driving parameters based on the actual driving parameters; The color wheel control signal and the adjusted reference driving parameters are used to generate a color wheel driving signal, which is used to drive the color wheel to rotate.

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