Projector

Abstract

The projector comprises a multi-color light source, a light machine, a projection lens, a light source driver and a light sensor, and the light source driver is connected with the light sensor and the multi-color light source; the light machine comprises an illumination light path, the illumination light path comprises a reflector, and the reflector is used for transmitting part of light beams emitted by the multi-color light source to the light sensor; the light sensor is used for detecting the light intensity of each color light beam in the light beams; the light source driver is used for adjusting the current of the multi-color light source based on the light intensity so as to adjust white balance. Based on the scheme, the white balance can be automatically adjusted, and the use experience of a user is improved.

Description

Technical Field

[0001] The present application relates to the technical field of projectors, and in particular to a projector. Background Art

[0002] The multi-color light source in the projector is generally composed of a red light source, a green light source, and a blue light source. When the multi-color light source emits a light beam, each color light beam generally maintains a specific ratio to maintain the white balance of the final imaging image of the projector.

[0003] However, the optical power of each color light source in a multi-color light source will age over time. In short, when the same voltage (or current) is used to drive a certain color light source, the intensity of the light beam that can be emitted by the new color light source will change as the color light source ages, which will cause the white balance of the final image of the projector to be abnormal, affecting the user experience.

[0004] Furthermore, there is no specific linear relationship between the intensity of the light beam emitted by the color light source and time, which makes it impossible to simply pre-set a corresponding relationship according to the use time of the color light source to adjust the white balance. Summary of the invention

[0005] The present application provides a projector, which includes a multi-color light source, an optical machine, and a projection lens, and includes a light source driver and a light sensor, wherein the light source driver is connected to the light sensor and the multi-color light source;

[0006] The optical machine comprises an illumination optical path, the illumination optical path comprises a reflector, and the reflector is used to transmit a part of the light beam emitted by the multi-color light source to the light sensor;

[0007] The light sensor is used to detect the light intensity of each color light beam in the light beam;

[0008] The light source driver is used to adjust the current of the multi-color light source based on the light intensity to adjust the white balance.

[0009] In the above scheme, the light beam in the present application is not only reflected after reaching the reflector, but also transmitted to a certain extent. Part of the light beam can pass through the reflector to reach the light sensor. The present application can detect the light intensity of each color light beam based on the partial light beam transmitted from the reflector, and adjust the current (or voltage) of at least one color light source in the multi-color light source based on the light intensity of each color light beam, so as to achieve the purpose of adjusting the white balance. At the same time, since the embodiment of the present application adjusts the white balance based on the detection of the light intensity of each color light beam, that is, the white balance is actually adjusted according to the actual use of each color light beam, the white balance can be achieved more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the light source structure in the relevant scheme;

[0011] Figure 2 A schematic diagram of a projector structure provided for one or more embodiments of the present application;

[0012] Figure 3A A schematic diagram of a reflector transmittance curve provided for one or more embodiments of the present application;

[0013] Figure 3B A schematic diagram of a reflectance curve of a reflector provided for one or more embodiments of the present application;

[0014] Figure 4 A schematic diagram of another projector structure provided for one or more embodiments of the present application;

[0015] Figure 5 A schematic diagram of a light spot shape provided for one or more embodiments of the present application;

[0016] Figure 6 A schematic diagram of another light spot shape provided for one or more embodiments of the present application;

[0017] Figure 7 A schematic diagram of another light spot shape provided for one or more embodiments of the present application;

[0018] Figure 8 A schematic diagram of light spot simulation provided for one or more embodiments of the present application;

[0019] Fig. 9 A lens data diagram provided for one or more embodiments of the present application;

[0020] Fig.10 A point diagram of an optical modulator provided for one or more embodiments of the present application;

[0021] Fig.11 A relative illumination curve diagram of a light modulator provided for one or more embodiments of the present application;

[0022] Fig.12 A field area and distortion curve diagram of an optical modulator provided for one or more embodiments of the present application;

[0023] Fig.13 A schematic diagram of another light spot shape provided for one or more embodiments of the present application;

[0024] Fig.14 A schematic diagram of a light sensor position provided for one or more embodiments of the present application;

[0025] Fig.15A schematic diagram of the position and spot area of ​​a red light beam on a light sensor provided by one or more embodiments of the present application;

[0026] Fig.16 A schematic diagram of the position and spot area of ​​a green light beam on a light sensor provided by one or more embodiments of the present application;

[0027] Fig.17 A schematic diagram of the position and spot area of ​​a blue light beam on a light sensor provided by one or more embodiments of the present application;

[0028] Fig.18 A schematic diagram of a reflector structure provided for one or more embodiments of the present application;

[0029] Fig.19 A schematic diagram of another projector structure provided for one or more embodiments of the present application;

[0030] Fig. 20 A schematic diagram of the structure of an optical processing component provided for one or more embodiments of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0032] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0033] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0034] The terms "including" and "having" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0035] A projector provided in an embodiment of the present application is exemplarily described below with reference to the accompanying drawings.

[0036] Figure 1 FIG. 1 is a schematic diagram of the light source structure in the related scheme. Figure 1 As shown, the light source can be an MCL type laser, which may include a first light emitting area 1101, a second light emitting area 1102, and a third light emitting area 1103 arranged on the same substrate, wherein the first light emitting area, the second light emitting area, and the third light emitting area are arranged adjacent to each other in sequence, and the area of ​​the third light emitting area is larger than the area of ​​the first light emitting area and the second light emitting area. The first light emitting area 1101 can emit blue laser, the second light emitting area 1102 emits green laser, and the third light emitting area 1103 emits red laser. The above three light emitting areas are located on the same laser package component, that is, the light emitting chips of the three-color laser are arranged in an array and packaged in a module, for example Figure 2 The MCL laser shown in the figure is a 4X5 light-emitting array. The MCL laser also includes a substrate 1110, on which a plurality of light-emitting chips are packaged, and a collimating lens group 1112 is also provided at the light-emitting surface of the MCL laser. The light-emitting surface of the MCL laser has multiple light-emitting areas, and the light beams emitted from different light-emitting areas have different colors. One row emits green light, one row emits blue light, and the remaining two rows emit red light. The MCL laser can output three primary colors sequentially. According to the principle of three-color mixing, the human eye cannot distinguish the color of light at a certain moment, and what is perceived is still mixed white light, that is, white balance is maintained. However, the condition for maintaining white balance is that the ratio between the light intensity of each color light beam is maintained at a certain value, or at least maintained within a certain range. For each color light source, the light intensity of the light beam that can be emitted under a certain current drive will change (generally decrease) with the aging of the light source, which causes an imbalance in the white balance of the projector.

[0037] Based on the above problems, an embodiment of the present application provides a projector. Figure 2 A schematic diagram of a projector structure provided for one or more embodiments of the present application. Figure 2 For the sake of simplicity, only part of the structure of the projector is illustrated. For other structures of the projector not illustrated, please refer to other drawings of the embodiments of the present application.

[0038] like Figure 2As shown, the projector may include a multicolor light source 100, an optical machine 200, and a projection lens 300 arranged in sequence along the optical path. In the embodiment of the present application, the multicolor light source 100 represents a light source capable of emitting multiple colors (e.g., red, green, and blue). More specifically, the multicolor light source 100 may be a semiconductor laser light source or an LED light source, etc., which is not limited in the embodiment of the present application. The optical machine 200 represents a functional unit for processing the light beam emitted by the multicolor light source 100 to obtain a light beam with image information. In some scenarios, the optical machine 200 may include an illumination optical path 210 for combining and shaping the light beam, and an optical modulator 220 for forming image information, such as a DMD (Digital Micromirror Device), which is composed of thousands of tiny mirrors with adjustable angles, which can process the light beam and reflect it to the projection lens 300. The projection lens 300 can be used to amplify the light beam with image information processed by the optical modulator 220, and project it onto a specific medium (e.g., a projection screen), thereby finally forming a projection picture.

[0039] The light sensor 104 represents a functional element that can detect the light intensity of each color light beam based on the received light beam, and the light sensor 104 can transmit the detection result to the light source driver 105 electrically connected thereto. The light source driver 105 can adjust the light intensity of at least one color light source in the multi-color light source 100 based on the light intensity of each color light beam received to adjust the white balance of the projector.

[0040] Based on the above scheme, the embodiment of the present application can detect the light beams emitted by the multi-color light source 100 to adjust the white balance of the projector and improve the user experience. At the same time, since the embodiment of the present application adjusts the white balance based on the detection of the light intensity of each color light beam, that is, the white balance is actually adjusted according to the actual use of each color light beam, the white balance can be achieved more accurately.

[0041] Continue reading Figure 2 In some embodiments, the illumination light path 210 may include a reflector 2101, which may be used to reflect and transmit the light beam. Figure 3A A schematic diagram of a reflector transmittance curve provided by one or more embodiments of the present application, Figure 3B A schematic diagram of a reflectance curve of a reflector provided in one or more embodiments of the present application. Figure 3A In the figure, the horizontal axis represents the wavelength of the light beam, and the vertical axis represents the transmittance of the reflector 2101. Figure 3B In FIG. 2 , the horizontal axis represents the wavelength of the light beam, and the vertical axis represents the reflectivity of the reflector 2101. Figure 3A and Figure 3BIt can be seen that the reflectivity of the reflector 2101 is less than 100%, and the transmittance of the reflector 2101 is less than 0.8%, that is, part of the light beam will pass through the reflector 2101, so in the present application, the light sensor 104 can be arranged on the other side of the reflector 2101 to receive the light beam transmitted by the reflector 2101. Since only part of the light beam can pass through the reflector 2101 and be received by the light sensor, the light intensity of the light beam received by the light sensor 104 can be reduced. At the same time, since the light beam can be folded by the action of the reflector 2101, the light modulator 220 and the projection lens 300 and other components can be arranged in a different straight line from the multi-color light source 100, thereby at least reducing the length of the projector in the same direction.

[0042] After research, the inventors found that the light beam emitted by the multicolor light source 100 has a high intensity, and even if only a small part of it is received by the light sensor 104 through the reflector 2101, it will still cause the light intensity received by the light sensor 104 to be too high, causing the light sensor 104 to be saturated and unable to accurately detect the light intensity. Among them, the saturation of the light sensor can mean that the light intensity of the light beam received by the light sensor has reached the maximum value of the light intensity that it can accurately detect. Taking a possible implementation as an example, the light sensor can generate a current of corresponding magnitude based on the intensity of the received light beam, and different magnitudes of current correspond to different light intensities. However, when the light intensity received by the light sensor is too high, there is no longer a specific corresponding relationship between the current it can generate and the light intensity, and the light sensor cannot accurately detect the light intensity. In some special scenarios, if the light intensity is too high, it may directly damage the light sensor.

[0043] Based on the above problems, the embodiment of the present application further improves the illumination light path 210 in the projector. The illumination light path 210 may include a light homogenizing element 2102 and a beam reducing element 2103 sequentially arranged along the light path. Figure 4 Another schematic diagram of a projector structure provided for one or more embodiments of the present application. The beam reduction element 2103 may include a first lens 401, a second lens 402 and a third lens 403. Specifically, the light homogenizing element 2102 may be a light pipe, which can achieve a light homogenizing effect, and the beam reduction element 2103 is used to change the exit angle of the light beam. The light beam adjusted by the third lens 403 of the beam reduction element 2103 meets the total reflection condition of the TIR prism 404, and the size of the light beam matches the size of the light modulator 220. The TIR prism 404 is located between the convex-planar lens and the light modulator 220, and can separate the illumination light beam and the projection light beam, thereby partially protecting the light modulator 220. In this structure, since the propagation path of the light beam can be changed by the reflector 2101, the size of the projector on a single straight line can be shortened.

[0044] By formula It can be seen that the optical power density is the ratio of the optical power to the spot area, where P represents the optical power density, W represents the optical power, and S represents the spot area. Therefore, it can be understood that, under the premise of constant optical power, the larger the spot area, the smaller the optical power density, that is, it can be understood that the light intensity of the light beam received by the optical sensor 104 is smaller, so as to avoid the optical sensor 104 being saturated and unable to accurately detect the light intensity.

[0045] In the embodiment of the present application, the receiving area of ​​the light sensor 104 is approximately 0.2×0.2 mm2, and the maximum illuminance that can be tolerated is 60000 lx, which is converted into a light power density of approximately 1.25 mW / (mm2).

[0046] The inventors improved the parameters of the focusing element 2103 so that the light spot corresponding to the light beam can fill the entire reflector 2101 as much as possible. Under the action of the focusing element 2103, the edge of the light spot is tangent to or coincides with all the edges of the reflective surface of the reflector 2101. Figure 5 A schematic diagram of a light spot shape provided for one or more embodiments of the present application. Figure 5 As shown, Figure 5 In the illustrated structure, the reflective surface of the reflector 2101 is square, and the shape of the light spot 501 is circular, so the edge of the light spot 501 can be tangent to all the edges of the reflective surface of the reflector 2101 . Figure 6 Another schematic diagram of a light spot shape is provided for one or more embodiments of the present application. Figure 6 As shown, if the shape of the light spot 501 is square and the reflecting surface of the reflector 2101 is circular, the corner of the light spot 501 can be made tangent to all edges of the reflecting surface of the reflector 2101. Figure 7 Another schematic diagram of a light spot shape provided for one or more embodiments of the present application. If the light spot 501 and the reflective surface of the reflector 2101 have the same shape, both are circular (or square), then the edge of the light spot 501 can be made to coincide with the edge of the reflective surface of the reflector 2101. Figure 7 FIG. 5 shows that the light spot 501 completely overlaps with the reflecting surface of the reflector 2101. Figure 5-Figure 7 The examples in are only a few of the countless possibilities. The shape of the light spot can be varied, and the shape of the reflective surface of the reflector 2101 can also be varied. The embodiments of the present application cannot list them one by one, and only the principle is limited here. In this way, the reflector 2101 can reflect all light beams (without considering the transmission effect) and make the area of ​​the light spot as large as possible. It can be seen from the above embodiments that when the area of ​​the light spot becomes larger and the light power remains unchanged, the light power density decreases, so the light intensity of the light beam received by the light sensor 104 can be reduced to avoid saturation of the light sensor 104.

[0047] Figure 8 A schematic diagram of light spot simulation provided by one or more embodiments of the present application. Figure 8 As shown, by optimizing the curvature radius, thickness, material, distance, etc. of the first lens 401, the second lens 402, and the third lens 403, the light spot area transmitted to the reflecting surface of the reflector 2101 can be maximized while meeting the imaging requirements of the light modulator 220, and its size is approximately 20 (mm) × 26 (mm). Fig. 9 A lens data diagram provided for one or more embodiments of the present application, such as Fig. 9 As shown, the first surface curvature of the first lens 401 (C1-RAY-IN) may be -84.997, the second surface curvature of the first lens 401 may be -8.719, the thickness of the first lens 401 may be 6.469 mm, the material of the first lens 401 may be H-ZLAF50E, and the radius of the first lens 401 may be 6.5 mm. The first surface curvature of the second lens 402 (C2-RAY-IN) may be -188.219, the second surface curvature of the second lens 402 may be -17.186, the thickness of the second lens 402 may be 6.928 mm, the material of the second lens 402 may be H-ZLAF50E, and the radius of the second lens 402 may be 8 mm. The first surface curvature of the third lens 403 (C3-RAY-IN) may be -31.713, the second surface of the third lens 403 is a plane, the thickness of the third lens 403 may be 7.024, and the radius of the third lens 403 may be 11.8 mm. The distance between the first lens 401 and the second lens 402 may be 11.483 mm, the distance between the second lens 402 and the reflector 2101 may be 14.355, and the distance between the reflector 2101 and the third lens 403 may be 16.829 mm. It should be noted that, in the embodiment of the present application, the first lens 401, the second lens 402, the third lens 403 and the reflector 2101 may include a first surface and a second surface, wherein the first surface refers to a surface facing the incident direction of the light beam, and the second surface is the opposite surface of the first surface.

[0048] In this structure, the point pattern on the light modulator surface is as follows: Fig.10 As shown, Fig.10 A point diagram of an optical modulator provided for one or more embodiments of the present application. The root mean square radius (RMS radius) and geometric radius (GEO radius) incident on the surface of the optical modulator 220 are both small, less than 286 μm and 627 μm, respectively, indicating that the convergence degree of the light beam meets the incidence requirements of the optical modulator 220. Fig.11 A relative illumination curve of a light modulator provided for one or more embodiments of the present application reflects the uniformity of the light beam incident to the light modulator 220 , and the relative illumination thereof is greater than 99%. Fig.12A light modulator field area and distortion curve diagram provided by one or more embodiments of the present application, comprising Fig.12 It can be seen that the field area (meridional field area is 1.6677 mm, sagittal field area is 1.7017 mm) and distortion (maximum distortion 0.1397%) of the light beam incident on the surface of the light modulator 220 meet the requirements.

[0049] In some scenarios, the light beam at the reflector 2101 may be a quasi-Gaussian beam, which is characterized in that: in the formed light spot, the light intensity at the center of the light spot is stronger, and the light intensity at the edge of the light spot is slightly weaker. Fig.13 A schematic diagram of another light spot shape provided for one or more embodiments of the present application. Fig.13 , the spot distribution imaging is measured on the incident surface of the spot, and the inner and outer circles are clearly divided by the color. For example, the converging spot is approximately circular, with the outermost circle appearing red, and the inner circles are purple, blue and other concentric circles. The above-mentioned phenomenon shows that the three-color light beams have spot divisions and uneven color distribution of the combined light.

[0050] Based on the above background, the embodiment of the present application further improves the position of the light sensor 104 . Fig.14 A schematic diagram of the position of a light sensor provided in one or more embodiments of the present application. Fig.14 As shown, in order to further reduce the light intensity of the light beam received by the light sensor 104, the light sensor 104 can be arranged near the edge of the reflective surface of the reflector 2101, so that the light sensor 104 is used to receive the light beam at the edge of the light spot. In this way, the possibility of saturation of the light sensor 104 can be further reduced.

[0051] In some scenarios, the multi-color light source 100 is generally composed of a red light source, a green light source, and a blue light source, which are used to emit a red light beam, a green light beam, and a blue light beam, respectively. Fig.15 A schematic diagram of the position and spot area of ​​a red light beam on a light sensor provided for one or more embodiments of the present application. Fig.16 A schematic diagram of the position and spot area of ​​a green light beam on a light sensor provided for one or more embodiments of the present application. Fig.17 A schematic diagram of the position and spot area of ​​a blue light beam on a light sensor provided by one or more embodiments of the present application. Figure 15-17 It can be seen that the light spots of the green light beam and the blue light beam basically overlap on the receiving surface of the light sensor 104, and the light spot areas are also basically equal. However, due to the light source, the red light beam does not overlap with the green and blue light beams. Based on this, the position of the light sensor 104 can be further optimized so that one light sensor 104 can receive the red light beam, the green light beam, and the blue light beam at the same time, thereby reducing the number of light sensors 104. In other embodiments, this embodiment can be combined with Fig.14The corresponding embodiments are implemented simultaneously, that is, by optimizing the position of the light sensor 104 , the light sensor 104 can simultaneously receive the red light beam, the green light beam and the blue light beam, and also receive the light beam at the edge of the light spot.

[0052] Fig.18 A schematic diagram of a reflector structure provided by one or more embodiments of the present application. Fig.18 As shown, the reflector 2101 may include a first surface 1801 and a second surface 1802, wherein the first surface 1801 is a surface facing the incident direction of the light beam, and the second surface 1802 is an opposite surface to the first surface. After the light beam reaches the reflector 2101, most of the light beam is reflected out through the first surface 1801, and a very small part of the light beam can pass through the first surface 1801, and continue to be transmitted after reaching the second surface 1802, and finally be received by the light sensor 104.

[0053] In the conventional solution, the second surface of the reflector 2101 is generally a smooth plane, but in the embodiment of the present application, in order to further reduce the light intensity of the light beam received by the optical sensor 104, the second surface can be improved, specifically, the second surface can be a frosted surface. The frosted surface can scatter the light beam, and the spot area of ​​the light beam scattered by the frosted surface will be further increased, and the light power density will be further reduced. In addition, the frosted surface has a lower transmittance than the traditional smooth plane, so it can further reduce the light intensity of the light beam received by the optical sensor 104.

[0054] The embodiment of the present application can reduce the light intensity of the light beam received by the light sensor 104 through one or more improvements of the above embodiments. For example, if the light intensity threshold value at which the light sensor 104 can accurately detect the light intensity is A, the above improvements can be used to make the light intensity of the light beam received by the light sensor 104 B, where B <A。

[0055] In other embodiments, the distribution of the light spot may be simulated and analyzed to further optimize the position of the light sensor 104 so that the uniformity of the light beam received by the light sensor 104 is greater than a uniformity threshold. This may reduce fluctuations in the light sensor 104 and improve the reliability of the collected data.

[0056] Fig.19 A schematic diagram of another projector structure provided by one or more embodiments of the present application. Fig.19As shown, the projector may include three parts: a multicolor light source 100, an optical machine 200, and a projection lens 300. During operation, the red, green, and blue lights in the multicolor light source 100 are lit in a certain timing sequence, and are subjected to shaping, homogenization, and the like of the illumination light path in the optical machine 200, and are then modulated by the optical modulator in the optical machine 200, converted into a light beam with image information, and then projected onto a medium through the magnification of the projection lens 300 to form a projection image. In addition, when the light beam passes through the reflector in the illumination light path, most of the light beam is reflected to the light modulator, and a small part of the light beam passes through the reflector and is received by the light sensor. The embodiment of the present application may further process the light beam signal received by the light sensor. Fig. 20 The schematic diagram of the structure of a light processing component provided by one or more embodiments of the present application. Specifically, the light processing component may include the light sensor 104 and the light source driver 105 in the above-mentioned embodiment. In addition, the light processing component may also include an amplifier 2001, an analog-to-digital converter 2002, etc. Fig. 20 As shown, the light sensor 104 can receive the light signal of the light beam and convert it into an electrical signal. The converted electrical signal is a tiny signal, so it needs to be performed through an amplifier 2001. At this time, the signal is still an analog signal, which is further converted into a digital signal through an analog-to-digital converter 2002, and then transmitted to the light source driver 105. The light source driver 105 can adjust the current of at least one color light source in the multi-color light source 100 based on the received digital signal to change the light intensity of the light beam emitted by the corresponding color light source, thereby achieving white balance adjustment.

[0057] In some embodiments, during the development stage of the projector, the driving current of the red, green and blue light sources can be adjusted so that the output of the three-color light sources reaches a white balance state, and the ratio of red, green and blue at this time is used as a reference for white balance correction.

[0058] During the entire life cycle of the projector, the light intensity of the output light beams of the red, green and blue light sources is monitored in real time by the light sensor 104. If the ratio of the green to red, green to blue output detected by the light sensor 104 deviates from the set reference value, the white balance correction algorithm will adjust the driving current of the red, green and blue light sources in real time to restore the output ratio of the light source to the white balance state.

[0059] The embodiment of the present application can provide two white balance adjustment modes. As a possible implementation method, the light intensity of the light beam output by the light source can be detected in real time by the light sensor 104, and the white balance correction can be completed in real time. As another possible implementation method, a certain time interval can be set, and the white balance correction can be performed at a certain interval. The two real-time methods can be used in combination according to the actual scene. In scenes with relatively large temperature changes, such as the projector startup stage, the first mode can be used to minimize the impact of temperature changes on white balance. After the projector is turned on for a period of time, the temperature remains in a relatively stable state, then it can be switched to the adjustment mode based on the time interval, while ensuring a good display effect, while reducing the power consumption of the machine.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0061] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A projector, characterized in that: The projector comprises a multi-color light source, an optical engine and a projection lens, and also comprises a light source driver and a light sensor, wherein the light source driver is connected to the light sensor and the multi-color light source; The optical machine comprises an illumination optical path, the illumination optical path comprises a reflector, and the reflector is used to transmit a part of the light beam emitted by the multi-color light source to the light sensor; The light sensor is used to detect the light intensity of each color light beam in the light beam; The light source driver is used to adjust the current of the multi-color light source based on the light intensity to adjust the white balance.

2. The projector according to claim 1, characterized in that: The illumination optical path also includes a light homogenizing element and a beam reducing element sequentially arranged along the optical path; The light homogenizing element is configured to homogenize the light beam; The beam reduction element is configured to adjust the emission angle of the light beam so that the light beam forms a light spot on the reflection surface of the reflector, and the edge of the light spot is tangent to or coincides with all edges of the reflection surface.

3. The projector according to claim 2, characterized in that: The beam reducing element comprises at least a first lens and a second lens; The first lens and the second lens are concave-convex lenses, and the first lens and the second lens are configured to adjust the emission angle of the light beam; The light homogenizing element at least includes a light guide tube, and the light homogenizing element is configured to homogenize the light beam.

4. The projector according to claim 2, characterized in that: The optical machine also includes a TIR prism and a light modulator; The beam reducing element further includes a third lens configured to adjust an exit angle of the light beam reflected by the reflector, to make the TIR prism perform total reflection on the light beam, and to make the light spot of the light beam match the light modulator.

5. The projector according to claim 2, characterized in that: The light intensity at the edge of the light spot corresponding to the light beam is smaller than the light intensity at the center of the light spot; The light sensor is configured to receive the light beam at an edge position of the light spot.

6. The projector according to claim 1, characterized in that: The multicolor light source is configured to emit a red light beam, a green light beam, and a blue light beam; There is an overlapping area among the light spots formed by the red light beam, the green light beam and the blue light beam on the reflector. The light sensor is arranged in the overlapping area and configured to simultaneously receive the red light beam, the green light beam and the blue light beam in the overlapping area.

7. The projector according to claim 1, characterized in that: The reflector comprises a first surface and a second surface, wherein the first surface is a surface facing the incident direction of the light beam, and the second surface is a surface opposite to the first surface; The first surface is configured to reflect a portion of the light beam and transmit a portion of the light beam; The second surface is configured to scatter the light beam transmitted by the first surface.

8. The projector according to claim 7, characterized in that: The second surface is a frosted surface.

9. The projector according to claim 1, characterized in that: The light intensity of the light beam received by the light sensor is less than a light intensity threshold.

10. The projector according to claim 1, characterized in that The uniformity of the light beam received by the light sensor is greater than a uniformity threshold.

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