Light source control method and system of projection equipment

Abstract

The invention relates to a light source control method and system for projection equipment, and the method comprises the steps: lightening a white light emitting unit in a light source module, analyzing the frame data of a to-be-projected picture, and obtaining the frame data of the to-be-projected picture according to the proportion weights of three color components; the integrated light source module is used for generating a driving instruction used for adjusting a color light-emitting unit in the light source module to control the light-emitting brightness of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit respectively, light output by the light-emitting units and light output by the white light-emitting unit are subjected to optical superposition, and a composite light source used for final projection is formed. And a light source driving unit. According to the scheme, the integrated light source module is adopted, the white light emitting unit serves as basic illumination, the red, green and blue independent controllable light emitting units are introduced, and a white light and colored light composite light source structure is constructed. Through real-time analysis of each frame of image data, the proportion weight of RGB color components is obtained, color compensation regulation and control of a light source end are realized, and the accurate restoration capability of picture colors is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optics, in particular to a light source control method and system of a projection device. BACKGROUND

[0002] At present, LCD (Liquid Crystal Display) technology is widely used in household and commercial projection devices, which has the advantages of relatively simple structure and low cost. However, the existing LCD projection light machine has obvious technical bottlenecks in color performance.

[0003] Firstly, the color gamut range of the LCD screen itself is limited by physical characteristics. For example, the color gamut of some LCD screens commonly seen in the market is only about 50%, and due to the limitation of the spectral composition of the light source and the difference in transmittance and reflectance of various optical devices (such as mirrors, lenses, polarizing plates, etc.) in the projection system, the effective color gamut in the overall projection effect is further weakened. Ultimately, the color range of the actual projected picture is often lower than the theoretical upper limit of the color gamut, and the color gamut performance is usually less than 50%.

[0004] Secondly, the LCD projection device also has significant deficiencies in color reproduction. Due to the lack of dynamic compensation mechanism for RGB primary colors in the projection system, it is difficult to ensure color accuracy (color accuracy). The current color adjustment method mainly relies on adjusting the image signal at the software level, such as reducing the brightness of a certain channel to achieve color balance of the overall picture. This method not only has low adjustment accuracy, but also significantly sacrifices the projection brightness. Brightness is one of the key indicators in projection devices, and a significant reduction in brightness to achieve color performance will seriously affect the user experience. Therefore, how to improve the color reproduction capability and color gamut coverage of the LCD projection device without sacrificing brightness is a technical problem that needs to be solved in the field.

[0005] There is no published solution that can dynamically improve the color reproduction capability and picture quality performance of the projected image from the perspective of light source control without changing the hardware structure of the liquid crystal screen. SUMMARY

[0006] The purpose of the present application is to solve the problems of low color reproduction, limited color gamut, and serious brightness loss of the LCD projection device.

[0007] According to an aspect of the present application, a light source control method of a projection device is provided, comprising:

[0008] turning on the white light emitting unit in the light source module as a basic light source;

[0009] analyzing the frame data of the picture to be projected to obtain the proportion weight of red, green and blue color components in the picture;

[0010] generate driving instructions for adjusting the color light-emitting units in the light source module according to the proportion weight of the three color components, wherein the color light-emitting units include light-emitting units for emitting red light, green light and blue light respectively;

[0011] The luminous intensity of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit is controlled respectively, and the light output by the three light-emitting units is optically superimposed with the light output by the white light-emitting unit to form a composite light source for final projection.

[0012] Preferably, the parsing of the frame data of the to-be-projected picture includes:

[0013] Obtain the current frame pixel data of the to-be-projected picture;

[0014] Separate the red, green and blue color component values of each pixel;

[0015] Accumulate the total values of the red, green and blue components in the entire frame image respectively;

[0016] Normalize the total values of each color to obtain the corresponding proportion weight of the color component.

[0017] Preferably, the generation of the driving instructions for adjusting the auxiliary light source according to the proportion weight of the three colors includes:

[0018] Generate pulse width modulation (PWM) parameters of the red light-emitting unit, the green light-emitting unit and the blue light-emitting unit respectively based on the proportion weight of each color component;

[0019] Generate independent driving signals for adjusting the luminous intensity of each light-emitting unit according to the PWM parameters.

[0020] According to another aspect of the present application, a light source control system of a projection device is also provided, which includes:

[0021] An integrated light source module, the light source module including: a white light-emitting unit for providing basic illumination; and color light-emitting units including red light-emitting units, green light-emitting units and blue light-emitting units for outputting color light to enhance color restoration;

[0022] An image analysis unit for parsing frame data of a to-be-projected picture and obtaining proportion weights of red, green and blue color components;

[0023] A light source driving unit for generating driving signals based on the color proportion weights and controlling the luminous intensity of the color light-emitting units respectively.

[0024] Preferably, the system further includes:

[0025] An optical superposition unit mixes the light output by the white light emitting unit and each of the color light emitting units to form a final composite projection light source, and the optical superposition unit comprises an integrating rod, a light mixing cavity or a diffuser.

[0026] Preferably, the system further comprises an LCD image modulation unit receiving the composite projection light source output by the optical superposition unit and performing image modulation.

[0027] Preferably, the system further comprises a lens module arranged behind the LCD image modulation unit and comprising:

[0028] An optical lens group comprising a spherical lens or a combination of a spherical lens and an aspherical lens for focusing the image source modulated by the LCD image modulation unit;

[0029] An electric focusing mechanism for driving the lens group to displace along the optical axis direction by a step motor to realize projection picture definition adjustment;

[0030] An adjustable diaphragm assembly arranged at the light path entrance end of the lens group for dynamically controlling the projection light flux.

[0031] Preferably, the image analysis unit comprises a video processing system level chip integrated with an I 2 C master controller, the I 2 C master controller comprises:

[0032] A serial data port electrically connected with the I 2 C slave device interface of the light source driving unit;

[0033] A serial clock port electrically connected with the clock synchronization interface of the light source driving unit.

[0034] Preferably, the light source driving unit comprises a PWM control chip, and the connection relationship of the PWM control chip with peripheral elements is as follows:

[0035] A VDD power supply pin is connected with a 3.3V power supply and grounded through two parallel decoupling capacitors;

[0036] The serial communication interface is configured as:

[0037] A serial data pin is connected with the serial data port of the video processing system level chip;

[0038] A serial clock pin is connected with the serial clock port of the video processing system level chip;

[0039] An output enable pin is grounded through a pull-down resistor and maintained in a low level active state;

[0040] The four-way PWM output ports are connected to the driving circuits of the white light, red light, green light and blue light emitting units respectively.

[0041] Preferably, the light source driving unit comprises an LED step-down constant current control chip, and the connection relationship of the LED step-down constant current control chip with peripheral elements is as follows:

[0042] The PWM control signal is input to a rectifier filter circuit composed of a transformer, a rectifier diode and a parallel electrolytic capacitor, and a 32V DC voltage is output to the power input end of the LED step-down constant current control chip;

[0043] The four-way brightness control signal input ports of the LED step-down constant current control chip are connected to the four-way PWM output ports of the PWM control chip;

[0044] The four-way power driving ports of the LED step-down constant current control chip drive the white light, red light, green light and blue light emitting units through four MOSFET switch tubes respectively;

[0045] The current detection pin of the LED step-down constant current control chip is connected to a current sampling resistor, the voltage across the current sampling resistor is collected, and the current sampling resistor is connected in series in the common ground loop of the white light, red light, green light and blue light emitting units respectively.

[0046] The application has the following beneficial effects: an integrated light source module is adopted, the white light emitting unit is used as the basic illumination, and the red, green and blue color independently controllable color light emitting units are introduced to construct a "white light + color light" composite light source structure. Through real-time analysis of each frame of image data, the proportion weight of the RGB color component is obtained, the brightness output of the color light emitting unit is dynamically adjusted according to the proportion, the color compensation regulation and control of the light source end are realized, and the accurate restoration ability of the picture color is improved. Through real-time enhancement compensation of the auxiliary light source in the RGB color direction, the overall spectral output range is effectively widened, and the color gamut coverage and color accuracy of the LCD system are improved. Different from the existing software adjustment mode, the present scheme adjusts at the hardware light source layer, does not realize color balance by compressing the channel brightness, avoids the problem of sacrificing brightness for picture quality, and thus brightness and color performance are taken into account. The present scheme adopts integrated design, is convenient for integration and upgrading in the existing LCD projection structure, does not need to greatly modify the optical architecture and image processing process, and has good engineering adaptability and economy. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort based on these drawings.

[0048] Figure 1 The logic block diagram of the light source control method of the projection device according to an embodiment of the present application;

[0049] Figure 2 The connection relationship diagram of the LED step-down constant current control chip and peripheral elements according to another embodiment of the present application;

[0050] Figure 3 The connection relationship diagram of the PWM control chip and peripheral elements according to another embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the accompanying drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0053] Reference Figure 1 The embodiment of the present application provides a light source control method of a projection device, comprising:

[0054] S10, lighting the white light emitting unit in the light source module as a basic light source. In this step, it needs to be explained that the white light emitting unit is the core lighting unit in the integrated light source module, and its output has high brightness and wide spectral coverage range, which is mainly used to provide basic brightness guarantee for the picture. In actual application, the white light emitting unit can adopt LED white light array, which has the advantages of fast response speed, low power consumption, high light efficiency, etc. At the same time, the white light emitting unit works in a constant light state, which provides a reference basis for subsequent compensation and adjustment of color light.

[0055] S20, analyze the frame data of the to-be-projected picture to obtain the proportion weight of red, green and blue color components in the picture. In this step, it needs to be explained that the analysis process of the frame data can be completed by an image analysis unit or a built-in SOC chip, which specifically includes: obtaining the pixel information of the current frame from the video source, extracting and counting the RGB component values of all pixel points, and calculating the relative proportion of red, green and blue colors in the frame image by normalizing the total value of each color component, that is, the proportion weight of the color component. These weight values will be used as the basis for subsequent adjustment of the driving of the color light source.

[0056] S30, generating a driving instruction for adjusting the color light-emitting unit in the light source module according to the proportion weight of the three color components, wherein the color light-emitting unit includes a light-emitting unit for emitting red light, green light and blue light respectively. In this step, it needs to be explained that according to the RGB proportion weight obtained by analyzing the last frame data, the system generates the corresponding PWM control parameter, which is used to control the duty cycle of the red, green and blue light-emitting units respectively, and then accurately adjusts the brightness output. The generation of the driving instruction can be completed by the built-in PWM control circuit or by the image processing chip through the I 2 C communication interface to the light source driving unit to drive different color light-emitting elements to output at different brightness.

[0057] S40, control the luminous brightness of the red, green and blue light-emitting units respectively, and optically superimpose the light output by the white light-emitting unit to form a composite light source for final projection. In this step, it needs to be explained that the RGB color light source adjusted by the driving instruction will emit light at a set brightness. These color lights and the output of the white light source are combined through the light mixing structure (such as an integrating rod, a light mixing cavity, a diffuser, etc.) in the optical path or through a natural light path superposition method to form a composite light source that acts on the LCD image modulation unit. The spectral composition of the composite light source is closer to the target color distribution due to color compensation, thereby improving the color reproduction and color gamut performance of the final image.

[0058] The technical scheme of the embodiment can significantly improve the color reproduction capability and color gamut performance of the LCD projection device.

[0059] By maintaining the constant output of the white light-emitting unit to ensure the basic brightness of the picture, dynamically analyzing the proportion weight of red, green and blue color components in each frame of image, and adjusting the brightness of the color light-emitting unit in real time based on the proportion, the output spectrum is more consistent with the color requirements of the image, thereby realizing the compensation and enhancement of the original image color on the optical level.

[0060] The scheme avoids the overall brightness loss caused by the traditional software method of "pressing dark a certain color" to realize color adjustment, and effectively breaks through the color performance bottleneck caused by the inherent color gamut limitation of the LCD panel by independently driving the output intensity of red light, green light and blue light, so that the projection picture has higher color saturation and more accurate color restoration ability without sacrificing brightness, which meets the dual requirements of "bright" and "accurate", and is especially suitable for projection application scenarios with high image quality requirements.

[0061] Further, the parsing of the frame data of the to-be-projected picture in S20 includes:

[0062] S21, obtaining the current frame pixel data of the to-be-projected picture. Specifically, the original pixel matrix of each frame image is extracted from the display control module or the video processing chip, which usually includes a two-dimensional pixel array corresponding to the resolution, and each pixel point contains channel values (such as RGB888 format) of red, green and blue colors.

[0063] S22, separating the red, green and blue color component values of each pixel. Specifically, all pixels in the current frame are parsed one by one, and the R, G and B channel values of each pixel are extracted and classified respectively to facilitate subsequent statistics and weight calculation.

[0064] S23, respectively accumulating the total values of red, green and blue components in the whole frame image. Specifically, the R, G and B component values of all pixel points in the current frame are accumulated within the channel to obtain the total brightness of the whole frame image in the red, green and blue channels, which are respectively denoted as R_total, G_total and B_total.

[0065] S24, normalizing the total values of each color to obtain the corresponding color component proportion weight. Specifically, R_total, G_total and B_total are normalized by summing up to calculate the relative proportion of each color in the whole frame image, that is:

[0066] R_ratio = R_total / (R_total+G_total+B_total),

[0067] G_ratio = G_total / (R_total+G_total+B_total),

[0068] B_ratio = B_total / (R_total+G_total+B_total).

[0069] In this way, the color proportion weight parameter for guiding the dimming of the color light emitting unit can be obtained.

[0070] The technical scheme of the embodiment is implemented, the contribution degree of red, green and blue three primary colors in the current image can be dynamically obtained based on the real color distribution of each frame of picture, so that the color light emitting module is driven to perform light distribution compensation with accurate light intensity output. This method effectively improves the color accuracy of image output and the consistency of picture perception, avoiding the brightness loss or color deviation problem caused by the rough color adjustment method in the traditional projection scheme.

[0071] Further, in S30, the driving instruction for adjusting the auxiliary light source is generated according to the proportion weight of the three colors, including:

[0072] S31, based on the proportion weight of each color component, the pulse width modulation (PWM) parameters of the red, green and blue light emitting units are generated respectively. Specifically, R_ratio, G_ratio and B_ratio calculated in the previous step S24 are taken as the proportion coefficients and are mapped to the duty cycle values of the PWM control signals of the corresponding color light sources. The higher the duty cycle of the PWM signal, the longer the light emitting time of the corresponding light source, and the higher the brightness; on the contrary, the lower the duty cycle, the lower the brightness. For example, when the proportion of red component in the image is 60%, and the proportions of green and blue are 25% and 15% respectively, the red light PWM duty cycle can be set to 60%, the green light to 25% and the blue light to 15% respectively, so that the red light emitting unit outputs higher brightness to match the image content requirements.

[0073] S32, according to the PWM parameters, independent driving signals for adjusting the brightness of each light emitting unit are generated. Specifically, the above duty cycle parameters are input to the light source driving chip (such as PCA9634PW or OC8201, etc.), and three independent PWM control signals are output by the chip and connected to the driving circuits of the red, green and blue light emitting units respectively, so as to realize independent adjustment of the brightness of each light source channel.

[0074] After constant current control and power amplification, these driving signals can ensure that the three-color light sources emit light stably at a preset brightness, providing accurate and dynamic matching light input for subsequent optical superposition and image projection.

[0075] The technical scheme of the embodiment is implemented, the contribution degree of red, green and blue three primary colors in the current image can be dynamically obtained based on the real color distribution of each frame of picture, so that the color light emitting module is driven to perform light distribution compensation with accurate light intensity output. This method effectively improves the color accuracy of image output and the consistency of picture perception, avoiding the brightness loss or color deviation problem caused by the rough color adjustment method in the traditional projection scheme.

[0076] The dynamic light adjustment mechanism not only effectively avoids color deviation, but also reduces unnecessary light energy loss, improves color performance without sacrificing brightness, and significantly improves the technical problem that the existing LCD projection equipment cannot balance high brightness and high color accuracy.

[0077] In another specific embodiment, the present application provides a light source control system of a projection device, which applies the light source control method of any one of the above projection devices, and the system comprises:

[0078] An integrated light source module, which comprises: a white light emitting unit for providing basic illumination; and a color light emitting unit comprising red, green and blue light emitting units for outputting color light to enhance color restoration.

[0079] An image analysis unit for analyzing frame data of a picture to be projected and obtaining proportion weights of red, green and blue color components.

[0080] A light source driving unit for generating driving signals based on the color proportion weights and controlling light emitting brightness of the color light emitting units respectively.

[0081] In this embodiment, it is to be noted that the light source control system of the projection device organically integrates the light source, image analysis and driving control modules to form a closed-loop dynamic light source adjustment architecture. The integrated light source module in the system comprises two parts: a white light emitting unit, which continuously emits light, for providing basic illumination brightness to ensure that the entire projection system has sufficient light output to meet high brightness projection requirements; and a color light emitting unit composed of three groups of red, green and blue light emitting devices for performing brightness compensation according to image content to enhance color accuracy and saturation and improve color performance.

[0082] The image analysis unit in the system can be an embedded SOC (such as MT9630) or an independent image processing module for data analysis of each frame of the projection content. The specific process includes extracting pixel data, separating RGB components, and statistically normalizing to obtain the proportion weights of each color. These weights reflect the distribution of color components in the current image.

[0083] The light source driving unit receives the color proportion weights output by the image analysis unit and generates independent driving signals for controlling the color light emitting units according to the color proportion weights. The driving signals are usually PWM modulation signals that can dynamically adjust the light source brightness of each color channel in real time. The specific implementation can use PWM control chips such as PCA9634PW and OC8201 to realize data communication and driving control with the image analysis unit through I 2 C bus or PWM input port.

[0084] In the system design, the output light of the color light source and the white light are spatially overlapped through an optical channel to realize optical superposition and form a composite light source for projection. The composite light source has better color restoration capability while maintaining high brightness.

[0085] The technical scheme of the embodiment can break through the technical bottleneck of the existing LCD projection device, which is limited by the physical characteristics of the screen, resulting in limited color gamut and color deviation. By increasing the dynamically adjustable color light source module and combining image real-time analysis and driving control, the system can flexibly adjust the light source output according to different picture content, realize adaptive optimization of color, and greatly improve the picture color performance and restoration accuracy without losing brightness, thereby effectively improving the overall quality of the projection picture and the user's visual experience.

[0086] Further, the system further comprises an optical superposition unit, a lens module, and an LCD image modulation unit. The optical superposition unit mixes the light output by the white light emitting unit and each color light emitting unit to form a final composite projection light source. The optical superposition unit comprises an integrating rod, a light mixing cavity, or a diffuser.

[0087] The LCD image modulation unit receives the composite projection light source output by the optical superposition unit and performs image modulation.

[0088] The lens module is arranged behind the LCD image modulation unit and comprises:

[0089] An optical lens group comprising a spherical lens or a combination of a spherical lens and an aspherical lens, for focusing the image source modulated by the LCD image modulation unit;

[0090] An electric focusing mechanism for driving the lens group to displace along the optical axis direction by a stepping motor, to realize projection picture definition adjustment;

[0091] An adjustable diaphragm assembly arranged at the light path entrance end of the lens group, for dynamically controlling the projection light flux.

[0092] In this embodiment, it should be noted that the system further integrates the optical superposition unit, the lens module, and the LCD image modulation unit on the basis of the aforementioned integrated light source module, image analysis unit, and light source driving unit, to build a complete optical projection path, ensuring that each link from light source generation, image modulation to imaging output closely cooperates, and improving the overall performance of the machine.

[0093] Specifically, the optical superposition unit is used to mix the multi-channel light beams from the white light emitting unit and the red, green, and blue color light emitting units in space and spectral direction, to form a composite projection light source with good consistency and uniform color. The optical superposition device can be selected in any of the following forms:

[0094] Integrating rod: for homogenizing the illumination distribution of different color light, to improve the light mixing uniformity;

[0095] Light mixing cavity: to enhance the fusion effect of multi-band light by internal reflection;

[0096] Diffuser: multi-angle diffusion of output light, realizing softening and uniformization.

[0097] The above-mentioned light mixing unit is usually arranged between the light emitting module and the image modulation unit, and is a key device for ensuring color balance and consistent projection brightness.

[0098] The lens module is the optical output end of the projection system, and is responsible for accurately projecting the modulated image light beam to the screen. Its composition includes:

[0099] The optical lens group is composed of a spherical lens or a combination of a spherical lens and an aspherical lens, which can effectively control aberration and edge defocus problems and improve image quality;

[0100] The electric focusing mechanism usually drives the lens group to move along the optical axis direction through a stepping motor to realize the focusing function, and adapts to different projection distances and screen sizes;

[0101] The adjustable diaphragm assembly is arranged at the entrance position of the light path and is used for adjusting the light flux and controlling the picture brightness or depth of field range.

[0102] The lens module has automatic adjustment capability, which significantly improves the convenience of user use and the accuracy of picture clarity control.

[0103] The LCD image modulation unit is arranged after the optical superposition unit and before the lens module, closely to the core position of the projection light path, and bears the image modulation function. It receives the illumination of the composite light source and realizes fine control of gray scale and image content through the transparency change of the liquid crystal pixels, thereby generating a modulated image light beam.

[0104] The position design of the LCD modulation unit is very critical. Being close to the lens group helps to reduce the light loss in the projection channel and enhance the image clarity, and both brightness and contrast performance are considered.

[0105] The technical scheme of the embodiment can realize dynamic control of the color auxiliary light source, build a complete and optimized optical path, make multi-color light efficiently fuse, accurately modulate the image, and output clear and sharp image. By introducing light mixing, automatic focusing, diaphragm control and other modules, the brightness uniformity, imaging stability and user control flexibility of the system are further enhanced, and the comprehensive performance of the entire projection equipment in color gamut performance, color accuracy control, picture clarity and light flux adjustment is effectively improved. The system solves the pain points of limited color gamut, color difference, brightness sacrifice and other pain points of existing LCD projection, and provides a new projection scheme with high restoration and high brightness for high-quality home theater, education projection, business display and other scenes.

[0106] For example, Figures 2-3As shown, in one embodiment, the image analysis unit comprises a video processing system level chip, the light source driving unit comprises a PWM control chip and an LED step-down constant current control chip, and the video processing system level chip integrates an I 2 C master controller, I 2 The C master controller comprises:

[0107] The serial data port is electrically connected with the I 2 C slave device interface of the light source driving unit;

[0108] The serial clock port is electrically connected with the clock synchronization interface of the light source driving unit.

[0109] The connection relationship of the PWM control chip and peripheral elements is as follows:

[0110] The VDD power supply pin is connected with a 3.3V power supply and grounded through parallel decoupling capacitors C1 and C2;

[0111] The serial communication interface is configured as: the serial data pin is connected with the serial data port of the video processing system level chip; and the serial clock pin is connected with the serial clock port of the video processing system level chip.

[0112] The output enable pin is grounded through a pull-down resistor R1 and maintained in a low-level active state.

[0113] The four-way PWM output port is connected with the driving circuit of the white light, red light, green light and blue light emitting units, respectively.

[0114] The connection relationship of the LED step-down constant current control chip and peripheral elements is as follows:

[0115] The PWM control signal is input to a rectifier filter circuit composed of a transformer T1, a rectifier diode D1 and parallel electrolytic capacitors CE1 and CE2, and a 32V direct current voltage is output to the power input end of the LED step-down constant current control chip;

[0116] The four-way brightness control signal input port of the LED step-down constant current control chip is connected with the four-way PWM output port of the PWM control chip.

[0117] The four-way power driving port of the LED step-down constant current control chip is connected with the white light, red light, green light and blue light emitting units through four MOSFET switching tubes, respectively.

[0118] The current detection pin of the LED step-down constant current control chip is connected with a current sampling resistor RCS1, the voltage across the current sampling resistor RCS1 is collected, and the current sampling resistor RCS1 is connected in series with the common ground circuit of the white light, red light, green light and blue light emitting units, respectively.

[0119] In this embodiment, it is pointed out that the projection device light source control system provided by the application comprises:

[0120] An image analysis unit comprising a video processing system level chip (MT9630), which is integrated with an I 2 A C master controller, which is electrically connected with an I 2 C slave device interface in the light source driving unit;

[0121] A serial clock port (SCL) is electrically connected with a clock synchronization interface of the light source driving unit;

[0122] Real-time analysis of video frame data of a projection picture is performed to obtain a proportion weight of red, green and blue color components of a current picture.

[0123] The light source driving unit comprises:

[0124] A PWM control chip (PCA9634PW, denoted as U1) for generating a PWM control signal according to RGB proportion information provided by the image analysis unit, and its peripheral connection comprises:

[0125] A VDD pin is connected with a 3.3V power supply through parallel decoupling capacitors C1 and C2;

[0126] An SDA (PIN18) and an SCL (PIN19) are respectively connected with a data and a clock port of a video processing chip of the MT9630;

[0127] An output enable pin (PIN15) is connected with the ground through a pull-down resistor R17 to maintain a low-level enable state;

[0128] Four PWM output ports respectively output PWM signals of WRGB and are connected with LED constant current control modules.

[0129] An LED step-down constant current control chip (OC8201, denoted as U3) for converting the PWM signal into a stable LED current driving signal, and its peripheral circuit comprises:

[0130] A rectifier filter circuit composed of a transformer T1 (E032), a rectifier diode D1 and parallel electrolytic capacitors CE1 and CE2, rectifies the PWM control signal into a 32V DC power supply voltage and inputs the voltage into a power supply pin of the U3;

[0131] PIN5 to PIN8 of the U3 respectively receive PWM dimming signals of white light, red light, green light and blue light channels;

[0132] Four power driving output ends respectively drive four LED light sources (LED1-LED4) through four MOSFETs (Q2, Q3, Q4 and Q5);

[0133] The current detection pin is connected with a current sampling resistor RCS1 for monitoring the actual current value of each LED channel, and the sampling resistor is connected in series with the four-way LED common ground circuit to form a constant current feedback closed loop.

[0134] In this embodiment, it is necessary to note that: in this embodiment, the RGB proportion of the image frame data is analyzed in real time, and the I 2 The C bus controls the PWM chip PCA9634PW to generate corresponding PWM signals, and the duty cycle changes in real time with the image color, so as to realize accurate color adjustment of the auxiliary light source. The PWM signal will not directly drive the LED, but will be handed over to the high-power LED constant current chip OC8201 for subsequent driving control, realizing safe and stable constant current output, effectively guaranteeing the brightness consistency and service life of the LED light source.

[0135] The whole control chain from image recognition to PWM generation to constant current driving to light brightness output forms a closed color adaptive adjustment mechanism, which can dynamically respond to the color composition of each frame of image, and significantly improves the color restoration accuracy.

[0136] The technical scheme of the embodiment can: realize real-time linkage control between the light source system and the projection image; dynamically adjust the brightness and proportion of the WRGB auxiliary light source, realize color enhancement without sacrificing brightness; ensure stable operation of the LED through constant current driving, reduce color temperature drift and light decay; use standard PWM and I 2 C communication to realize a modular, low-cost and expandable light source control system; ultimately realize the improvement of the color gamut performance and color restoration accuracy of the LCD projection system, and achieve an optimized balance between brightness and color quality.

[0137] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for controlling the light source of a projection device, characterized in that, include: The white light-emitting unit in the light source module is illuminated as the basic light source; Analyze the frame data of the image to be projected to obtain the proportion weights of the three color components of red, green and blue in the image; Based on the weighting of the three color components, driving instructions are generated to adjust the colored light-emitting units in the light source module, wherein the colored light-emitting units include light-emitting units for emitting red light, green light and blue light respectively. The brightness of the red, green and blue light-emitting units is controlled respectively, and the light output by them is optically superimposed with the light output by the white light-emitting unit to form a composite light source for final projection.

2. The light source control method for a projection device according to claim 1, characterized in that, The frame data of the image to be projected, which is being parsed, includes: Obtain the current frame pixel data of the image to be projected; Separate the red, green, and blue color component values ​​of each pixel; The total values ​​of the red, green, and blue components in the entire frame of the image are summed separately. The total values ​​of each color are normalized to obtain the corresponding weights of the color components.

3. The light source control method for a projection device according to claim 2, characterized in that, The step of generating the driving instructions for adjusting the auxiliary light source based on the proportion weights of the three colors mentioned above includes: Based on the proportion weight of each color component, pulse width modulation (PWM) parameters for red, green, and blue light-emitting units are generated respectively. Based on the PWM parameters, independent drive signals are generated to adjust the brightness of each light-emitting unit.

4. A light source control system for a projection device, employing the light source control method for a projection device as described in any one of claims 1-3, characterized in that, The system includes: An integrated light source module includes: a white light emitting unit for providing basic lighting; and a colored light emitting unit, including red, green, and blue light emitting units, for outputting colored light to enhance color reproduction. The image analysis unit is used to parse the frame data of the image to be projected and obtain the proportion weights of the three color components: red, green, and blue. A light source driving unit is used to generate driving signals based on the color proportion weights and to control the luminous brightness of the color light-emitting units respectively.

5. The light source control system of the projection device according to claim 4, characterized in that, The system also includes: An optical superposition unit mixes the light output from the white light emitting unit and each of the colored light emitting units to form a final composite projection light source. The optical superposition unit includes an integrating bar, a mixing cavity, or a diffuser.

6. The light source control system of the projection device according to claim 5, characterized in that, The system also includes an LCD image modulation unit, which receives the composite projection light source output by the optical overlay unit and performs image modulation.

7. The light source control system of the projection device according to claim 6, characterized in that, The system also includes a lens module, which is disposed after the LCD image modulation unit and includes: An optical lens assembly, comprising a spherical lens, or a combination of a spherical lens and an aspherical lens, is used to focus and image the image source modulated by the LCD image modulation unit. The electric focusing mechanism drives the lens assembly to move along the optical axis via a stepper motor, thereby adjusting the sharpness of the projected image. An adjustable aperture assembly is located at the optical path entrance of the lens group and is used to dynamically control the projection light flux.

8. The light source control system of the projection device according to claim 4, characterized in that, The image analysis unit includes a video processing system-on-a-chip, which integrates I / O... 2 C main controller, the I 2 The C main controller includes: The serial data port is connected to the I / O port of the light source driving unit. 2 C is electrically connected to the device interface; The serial clock port is electrically connected to the clock synchronization interface of the light source driving unit.

9. The light source control system of the projection device according to claim 8, characterized in that, The light source driving unit includes a PWM control chip, and the connection relationship between the PWM control chip and peripheral components is as follows: The VDD power supply pin is connected to a 3.3V power supply and grounded through two decoupling capacitors in parallel. The serial communication interface is configured as follows: The serial data pin is connected to the serial data port of the video processing system-on-a-chip; The serial clock pin is connected to the serial clock port of the video processing system-on-a-chip; The output enable pin is grounded via a pull-down resistor and remains active low. The four PWM output ports are respectively connected to the driving circuits of the white, red, green, and blue light-emitting units.

10. The light source control system of the projection device according to claim 9, characterized in that, The light source driving unit includes an LED buck constant current control chip, and the connection relationship between the LED buck constant current control chip and peripheral components is as follows: The PWM control signal is input to the rectifier and filter circuit consisting of a transformer, rectifier diodes and parallel electrolytic capacitors, and outputs a 32V DC voltage to the power input terminal of the LED step-down constant current control chip. The four brightness control signal input ports of the LED buck constant current control chip are connected to the four PWM output ports of the PWM control chip. The four power drive ports of the LED step-down constant current control chip drive white, red, green and blue light-emitting units respectively through four MOSFET switching transistors; The current detection pin of the LED step-down constant current control chip is connected to the current sampling resistor to collect the voltage across the current sampling resistor. The current sampling resistor is connected in series in the common ground loop of the white light, red light, green light and blue light emitting units respectively.

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