Laser projection equipment

Abstract

The present application provides a laser projection device, which uses a laser component having a first light emitting area, a second light emitting area and a third light emitting area, which respectively emit a first color laser beam, a second color laser beam and a third color laser beam; a light combining lens group, including a plurality of light combining lenses, which are respectively arranged corresponding to the first light emitting area, the second light emitting area and the third light emitting area, and are used to combine the laser beams emitted from the above-mentioned light emitting areas and emit them out of the light outlet of the light source, wherein the first color laser beam and the second color laser beam pass through a diffusion component before being combined with the third color laser beam.

Description

[0001] This application is a divisional application based on Chinese invention application 202180023597.X (2021-3-19), invention title: A laser projection device.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to the Chinese patent application filed with the China Patent Office on March 31, 2020, with application number 202010247119.4, and invention name "Laser Projection Device," and the Chinese patent application filed with the China Patent Office on March 31, 2020, with application number 202010247120.7, and invention name "Laser Projection Device," the entire contents of which are incorporated by reference into this application. Technical Field

[0004] The present application relates to the field of laser projection display technology, and in particular to a laser projection device. Background Art

[0005] Laser light sources offer advantages such as good monochromaticity, high brightness, and long life, making them ideal light sources. As laser device power increases to meet the requirements of industrial applications, lasers are increasingly being used as lighting sources. For example, in recent years, lasers have been used as projection light sources in projection equipment, gradually replacing mercury lamps. Compared to LED light sources, lasers also offer the advantages of low etendue and high brightness.

[0006] Lasers are categorized by their emission type: blue lasers, red lasers, and green lasers, emitting blue, red, and green lasers, respectively. Blue lasers were the first to be industrialized. Red and green lasers were previously unusable due to limitations in their power output (e.g., emitting power less than 1W and low brightness). Consequently, most laser projection light sources in the industry are hybrid laser sources combining monochromatic lasers (blue lasers) and fluorescent light, with the fluorescent light being excited by the blue laser.

[0007] Solid-state lasers are essentially a PN junction semiconductor, such as Figure 1 The schematic diagram of the laser light-emitting chip shown in the figure. The active layer is located between the P-type semiconductor and the N-type semiconductor. The oscillation of the resonant cavity in the active region causes lasers of different wavelengths to be emitted from the front cavity surface. Specifically, the laser beam is as follows: Figure 2-1 As shown, a radial beam is emitted from the light-emitting point. The α and β in the figure refer to the divergence angles of the slow axis and the fast axis respectively. It can be seen from the figure that the fast axis diverges faster and the angle is larger, while the slow axis diverges relatively slowly and the angle is smaller, so the shape of the laser beam is elliptical.

[0008] Among them, blue laser and green laser can be generated by gallium arsenide luminescent materials, and red laser is generated by gallium nitride luminescent materials. Due to the different luminescence mechanisms of luminescent materials, in the process of generating different colored lasers, the luminescence efficiency of red laser is lower and the thermal conversion rate is higher. The luminescence efficiency of blue laser and green laser is relatively high, and the luminescence requirements can be met by setting a luminescence point on the corresponding chip. In order to meet the requirements of luminous power, such as Figure 2-2 As shown, multiple light-emitting points need to be set on the red laser chip to increase the light-emitting power, which also makes the size of the red laser beam relatively large. At the same time, due to the different light-emitting mechanisms of the light-emitting materials, the divergence speed of the fast and slow axes of the red laser is greater than that of the blue and green lasers.

[0009] However, the differences between the red laser and the blue and green lasers mentioned above result in some problems with the quality and efficiency of the three-color light combination when the three-color laser is used as a light source. In laser projection equipment, this will cause a decrease in the quality of the projected image. Summary of the Invention

[0010] The present application provides a laser projection device, including a light source for providing an illumination beam; an optical engine for modulating the illumination beam; and a lens for receiving the modulated illumination beam for projecting an image. The light source includes:

[0011] A laser assembly having a first light emitting area, a second light emitting area and a third light emitting area, which respectively emit a first color laser beam, a second color laser beam and a third color laser beam;

[0012] A light combining lens assembly, comprising a plurality of light combining lenses, which are respectively arranged corresponding to the first light emitting area, the second light emitting area and the third light emitting area, and are used to combine the laser beams emitted from the above light emitting areas and emit them out of the light source outlet;

[0013] Among them, the beam angles of the first color laser beam, the second color laser beam and the third color laser beam after being combined are greater than the beam angle directly emitted from the first light exit area and the second light exit area, and are both less than or equal to the beam angle of the third color laser beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0015] Figure 1 This is a schematic diagram of the principle of a laser light-emitting chip;

[0016] Figure 2-1 This is a schematic diagram of the principle of the laser light-emitting chip emitting a light beam;

[0017] Figure 2-2 This is a schematic diagram of the principle structure of a red laser light-emitting chip;

[0018] Figure 3 A schematic structural diagram of a laser projection device provided in an embodiment of the present application;

[0019] Figure 4-1 A schematic diagram of an optical engine structure provided in an embodiment of the present application;

[0020] Figure 4-2 A schematic diagram of the decomposition structure of an optical engine provided for the implementation of this application;

[0021] Figure 5 Schematic diagram of the optical principle of the laser projection device provided in an embodiment of the present application;

[0022] Figure 6-1 A schematic diagram of a light source structure provided in an embodiment of the present application;

[0023] Figure 6-2 for Figure 6-1 A schematic cross-sectional view of a light source structure;

[0024] Figure 7-1 A schematic diagram of the internal structure of a light source provided in an embodiment of the present application;

[0025] Figure 7-2 A schematic diagram of the internal structure of a light source provided in an embodiment of the present application;

[0026] Figure 7-3 A schematic diagram of the internal structure of another light source provided in an embodiment of the present application;

[0027] Figure 7-4 A schematic diagram of the internal structure of another light source provided in an embodiment of the present application;

[0028] Figure 8-1 for Figure 6-1 Schematic diagram of the laser structure;

[0029] Figure 8-2 for Figure 6-1 Schematic diagram of the laser assembly structure;

[0030] Figure 9-1 Schematic diagram of a light source structure;

[0031] Figure 9-2 for Figure 9-1Spot distribution diagram of the illumination beam output by the central light source;

[0032] Figure 10 The figure is a structural diagram of a light-combining lens. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] Figure 3 A schematic diagram of the structure of a laser projection device is shown. Figure 3 The structure and working process of the laser projection device of this embodiment are described.

[0035] The laser projection device 10 comprises a housing 101 and a base 012. The housing 101 and base 012 form a housing space within which are located a light source 100, an optical engine 200, and a lens 300, mounted on the base 012. These three components constitute the optical engine and are connected in sequence along the beam's propagation direction. Each of these components is enclosed in a corresponding housing to support the optical components and ensure they meet certain sealing or airtight requirements.

[0036] A plurality of circuit boards 400 are also included in the accommodation space formed by the entire housing 101 and the base 012 . The plurality of circuit boards 400 are parallel to each other and are located inside the entire housing 101 and vertically disposed on the base 012 .

[0037] In one specific implementation, see Figure 3 The optical engine 200 and lens 300 are connected and arranged along a first direction of the entire device. For example, the first direction can be the width of the entire device, or depending on the usage, the first direction is opposite to the user's viewing direction. The connection direction of the light source 100 and the optical engine 200 is perpendicular to the first direction. As a result, the optical engine composed of the light source 100, optical engine 200, and lens 300 forms an "L" shape. The optical engine is located at the corner of the "L", causing the optical axis to bend 90 degrees, thereby compressing the length of the optical path in one direction.

[0038] See also Figure 3The laser projection device 10 further includes a plurality of circuit boards 400, which are arranged vertically relative to the bottom 102 and along the inner side of the overall housing 101. The figure only schematically illustrates a portion of the overall housing 101. Specifically, the plurality of circuit boards 400 are arranged parallel to each other and close to the inner side of the overall housing 101. The overall housing 101 is typically a housing including a top cover. The housing described herein may refer to the outer shell surrounding the device body.

[0039] The multiple circuit boards 400 include a power supply board, also known as a power board, which is used to provide power for multiple modules of the device; a display board, which is mainly used to control the imaging of the projection system, which is a DLP system in this embodiment, such as the generation of DMD chip signals, the output of light source timing signals and PWM brightness dimming signals, etc.; a signal transmission board, also known as a TV board, which is mainly used to decode the video signal to form an image signal and transmit it to the display board for further image processing.

[0040] Figure 5 The optical path principle diagram of the above laser projection device is given as an example. Figure 5 As shown, the light beam output by the light source 100 is incident on the optical engine 200, and the optical engine 200 then transmits the light beam to the lens 300. In one specific implementation, the light source 100 is a three-color laser light source that can output red, green and blue lasers. The light source 100 also includes a plurality of optical lenses to combine and converge the laser beams. Since the laser itself has strong coherence, in order to improve the speckle problem caused by laser projection, a speckle elimination component may be provided in the optical path from the light source 100 to the optical engine 200, such as a moving diffusion component. After the light beam is diffused by the moving diffusion component, the divergence angle of the light beam can be increased, which is conducive to improving the speckle phenomenon. The moving diffusion component can be provided in the light source 100 or in the optical engine 200.

[0041] The light beam emitted from light source 100 enters optical engine 200. A homogenizing component, such as a light pipe, is typically located at the front end of optical engine 200. This component receives the light beam from the light source and mixes and homogenizes the light. The rectangular exit of the light pipe shapes the light spot. Optical engine 200 also includes multiple lens elements. TIR or RTIR prisms form the illumination light path, directing the light beam to a key component—a light valve. The light valve modulates the light beam, which then enters the lens assembly of lens 300 for imaging.

[0042] Depending on the projection architecture, light valves can include various types, such as LCOS, LCD, or DMD. In this example, a DLP (Digital Light Processing) projection architecture is used, and the light valve is a DMD chip, also known as a digital micromirror array. Before the light beam from light source 100 reaches the DMD light valve, it undergoes optical mechanical shaping to meet the illumination size and incident angle required by the DMD. The DMD surface comprises thousands of tiny mirrors, each of which can be individually driven for deflection. For example, the DMD chip provided by TI can achieve a deflection range of ±12 degrees or ±17 degrees. Light reflected at a positive deflection angle is called ON light, while light reflected at a negative deflection angle is called OFF light. OFF light is ineffective light and is typically reflected by the housing or absorbed by a light-absorbing device. ON light is the effective light beam that is received by the tiny mirrors on the DMD light valve surface and incident on the lens unit 300 at a positive deflection angle for projection imaging. The quality of the illumination light beam emitted by the light source 100 directly affects the quality of the light beam irradiated on the surface of the light valve DMD, and thus the light beam is projected by the lens 300 and reflected on the projection screen.

[0043] In this example, lens 300 is an ultra-short-throw projection lens. The light beam modulated by the light valve enters the lens and is finally emitted in an oblique upward direction. This is different from the light emission method of traditional long-throw projection in which the optical axis of the projection light beam is located at the vertical line of the projection screen. The ultra-short-throw projection lens usually has an offset of 120% to 150% relative to the projection screen. This projection method has a smaller throw ratio (which can be understood as the ratio of the distance between the projection host and the projection screen to the diagonal size of the projection screen), such as about 0.2 or even smaller, which can make the projection device closer to the projection screen, making it suitable for home use. However, this light emission method also determines that the light beam has a higher uniformity. Otherwise, compared with traditional long-throw projection, the brightness or color unevenness of the projection screen will be more obvious.

[0044] In this example, when using a single DMD light valve component, light source 100 can sequentially output the three primary colors. Based on the principle of three-color light mixing, the human eye cannot distinguish the color of light at any given moment and still perceives a mixed white light. However, when using multiple light valve components, such as three DMDs or a three-chip LCD light valve, the three primary colors in light source 100 can be illuminated simultaneously to output white light.

[0045] It should be noted that in order to enhance the brightness of the light source, a yellow primary color can be added to the three primary colors. The yellow primary light can be produced by superimposing red light and green light. Therefore, when the four colors are output sequentially by controlling the red, green and blue lasers, there can actually be a period when the two primary colors are output at the same time, that is, red and green have an overlapping period, which is used to control the output of the yellow primary color.

[0046] Figure 4-1 Shown Figure 3 Schematic diagram of the optical engine structure of a laser projection device. Specifically, it includes a light source 100, an optical engine 200, and a lens 300. The three are connected together by structural components, and the optical path is sealed within the shell structure.

[0047] Figure 4-2 A schematic diagram of the decomposed structure of an optical engine structure is shown. Schematically, the light beam emitted by the light source 100 passes through a diffuser wheel 140 and then enters the light rod 210. The diffuser wheel 140 can diverge the angle of the laser beam through the diffusion component, creating a variety of divergence angles, thereby playing the role of dispersing speckles. The light rod 210 is a homogenizing component with a rectangular light input surface and a light output surface. After the laser beam enters the light rod, it is reflected multiple times using the principle of total internal reflection, which can also homogenize the energy distribution of the light spot. By setting the area of ​​the light output surface and the light input surface, the divergence angle of the beam is constrained. The light output surface of the light rod 210 and the light input surface of the light valve 220 are conjugate to each other. Therefore, it can be understood that the light output surface of the light rod is the object plane and the light input surface of the light valve is the image plane. The light beams at the light entrance and exit surfaces of the light rod 210 satisfy the Lagrange invariant law, that is, the integral value of the incident angle and area of ​​the light beam at the light entrance surface is equal to the integral value of the incident angle and area of ​​the light exit surface. In this way, the incident angle and the size of the light spot at the light entrance surface of the light rod determine the beam index of the light beam in the subsequent optical path.

[0048] Figure 6-1 Shown Figure 3 A light source structure in a laser projection device. Figure 6-1 As shown, the light source unit 100 of the laser projection device 10 includes a housing 150 and a laser assembly 110 . The light source unit 100 is a three-color laser light source, and the three-color laser beams are emitted from an opening 152 of the light source unit 100 .

[0049] Figure 6-2 for Figure 6-1 Schematic cross-sectional view of the light source structure in FIG. The light source housing 150 has a housing cavity 151, in which the laser assembly 110 and the light combining mirror assembly 120 are at least partially accommodated. The housing cavity 151 has an opening 152 along the light emitting direction of the light source, and a focusing lens 112 is provided at the opening for converging the light beam.

[0050] In this example, the laser assembly 110 is a laser assembly capable of emitting three colors of laser light. The laser assembly has a first light output region, a second light output region, and a third light output region, which respectively emit a first color laser beam, a second color laser beam, and a third color laser beam. The wavelengths of the first color laser beam, the second color laser beam, and the third color laser beam are different.

[0051] like Figure 8-1 An MCL laser is shown, comprising a first light emitting region 1101, a second light emitting region 1102, and a third light emitting region 1103, which emit blue laser, green laser, and red laser respectively.

[0052] In one embodiment, the three light-emitting areas mentioned above are located on the same laser package assembly, that is, the light-emitting chips of the three-color laser are arranged in an array and packaged in a module. For example, the MCL laser used in this example is a 4X5 light-emitting array. The laser assembly 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 laser assembly. The light-emitting surface of the laser assembly has a plurality of 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 above-mentioned laser assembly packages the three-color light-emitting chips together, and its volume is relatively small, which is conducive to reducing the volume of the light source device.

[0053] It should be noted that the laser assembly in this example is not limited to the above-mentioned 4X5 array, but can also be other array arrangements, such as a 3X5 array, or a 2X7 array, as long as it can emit three-color laser beams.

[0054] The laser assembly is surrounded by a circuit board parallel to the light-emitting surface of the laser, which provides the laser with a driving control signal, such as Figure 8-2 As shown, the circuit board is a flat structure, with pins 1111 on both sides of the laser. The pins 1111 are respectively welded or plugged into circuit boards 1113a and 1113b on that side which are almost parallel to the plane where the laser is located. 1113a and 1113b can be integrally formed and surround the outside of the laser assembly substrate 1110, or 1113a and 1113b can also be two independent circuit boards, which enclose the laser assembly 110. In this way, the packaged laser assembly can also be regarded as a flat structure, which is easy to install, saves space, and is also conducive to the miniaturization of the light source device.

[0055] like Figure 6-1 and Figure 6-2 As shown, the laser assembly 110 is fixed to the shell 150 by screws, and emits a three-color laser beam into the accommodating cavity inside the light source shell, facing the light-emitting surface of the laser assembly. A light-combining mirror assembly 120 is arranged in the accommodating cavity inside the shell.

[0056] As well as Figure 6-1As shown, a diffuser 140 is also provided in the light output path of the light source. This diffuser 140 is positioned on the light output path of the focusing lens. The light beam, diffused by diffuser 140, enters a light homogenization component (not shown). Diffuser 140 can be a rotating diffuser, forming a diffuser wheel structure. This rotational diffusion can despeckle the light beam, improving beam quality and reducing the speckle effect in the projected image. The diffused light beam then enters the light homogenization component, which can specifically be a light rod or a fly-eye lens assembly.

[0057] The light combining lens group 120 is provided with a plurality of light combining lenses corresponding to each light emitting area of ​​the laser assembly 110 , and each light combining lens corresponds to a different light emitting area and is used to combine the laser light beams from different light emitting areas.

[0058] The light combining mirror assembly 120 combines the light beams from different regions so as to output them from the light outlet of the laser light source. Figure 6-2 As shown, the light-combining lens assembly 120 includes three light-combining lenses 1201, 1202, and 1203, which are sequentially arranged along the optical transmission path of the laser. Different light-combining lenses are arranged on the output light paths of the light-emitting areas emitting corresponding color light beams. Each light-combining lens can reflect the light beams from the corresponding light-emitting areas. The reflected light beams are all along the direction of the laser light source's light outlet, and the light beams of each color are converged to form white light.

[0059] Specifically, the first light-combining lens 1201 is used to receive the light beam emitted from the first light-emitting area, the second light-combining lens 1202 is used to receive the light beam emitted from the second light-emitting area, and the third light-combining lens 1203 is used to receive the light beam emitted from the third light-emitting area.

[0060] Figure 7-1 A schematic diagram of the optical path of a light source is shown. Multiple light-combining lenses 1201, 1202, and 1203 are each used to reflect light beams emitted from corresponding light-exiting areas toward the light outlet of the light source. The multiple light-combining lenses are arranged sequentially toward the light outlet of the laser light source, and at least one light-combining lens can transmit light beams of corresponding colors from other light-exiting areas and combine them with the reflected light beams, emitting them along the light outlet of the laser light source. The spot areas of the first-color laser beam and the second-color laser beam are both smaller than the spot area of ​​the third-color laser beam. When the first and second colors are blue and green, and the third color is red, the beam angles of the first-color laser beam and the second-color laser beam are different from the angle of the third-color laser beam. Specifically, the beam angles of the first-color laser beam and the second-color laser beam are both smaller than the beam angle of the third-color laser beam.

[0061] Specifically, the angles between the light-receiving surfaces of the first light-combining lens 1201, the second light-combining lens 1202, and the third light-combining lens 1203 and the green laser, blue laser, and red laser beams emitted from the light-emitting area of ​​the laser assembly can all be set to 45°±2°, wherein the first light-combining lens 1201 is a reflector, and the second light-combining lens 1202 and the third light-combining lens 1203 are dichroic filters. The first light-combining lens 1201, the second light-combining lens 1202, and the third light-combining lens 1203 are arranged parallel to each other.

[0062] The first light-emitting region 1101 emits a first-color laser beam, and the first light-combining lens 1201 is a reflector for reflecting the first-color laser beam. The reflective surface of the first light-combining lens 1201 is convex. After reflection by the first light-combining lens 1201, the first-color laser beam is diverged. In one specific implementation, the first-color laser beam is collimated by the collimating lens group when it is emitted from the laser assembly 110 and can be approximately regarded as a parallel beam. After reflection by the first light-combining lens 1201, the divergence angle of the approximately parallel beam increases by 2° to 8°, and the spot of the first-color laser beam is within the same range as the spot of the third-color laser beam.

[0063] Furthermore, the second light-emitting region 1102 emits a second color laser beam, and the second light-combining lens 1202 is used to reflect the second color laser beam and transmit the first color laser beam, forming a dichroic mirror. The reflective surface of the second light-combining lens 1202 is convex. After reflection by the second light-combining lens 1202, the second color laser beam is diverged. In one specific implementation, the second color laser beam is collimated by the collimating lens group upon exiting the laser assembly 110 and can be approximately considered a parallel beam. After reflection by the first light-combining lens 1202, the approximately parallel beam increases by 2° to 8°, and the spot of the second color laser beam is located within the same range as the spot of the third color laser beam.

[0064] As well as Figure 7-1 As shown, the third light-emitting area 1103 emits a third color laser, and the third light-combining lens 1203 is used to reflect the third color laser beam and transmit the first and second color laser beams. The third light-combining lens 1203 is a dichroic mirror, with both its reflective and transmissive surfaces being flat. After being reflected by the third light-combining lens 1202, the third color laser beam is emitted toward the light outlet of the light source. Furthermore, after being transmitted by the third light-combining lens 1303, the first and second color laser beams are also emitted toward the light outlet of the light source.

[0065] In the MCL packaged laser of this example, the third color laser beam is a red laser beam, which is two rows or two columns. The third light-combining lens is used to receive two rows of red laser beams. Its size is larger than that of the first light-combining lens and the second light-combining lens, so that it can receive all the beams transmitted and reflected from the second light-combining lens.

[0066] In this example, the third light-emitting area 1103 emits two laser beams of the third color, the first light-emitting area 1101 emits one laser beam of the first color, and the second light-emitting area 1102 emits one laser beam of the second color. When these three laser beams of color illuminate the third light-combining lens 1203, preferably, the position where the first and second laser beams of color are incident on the third light-combining lens 1203 is between the two laser beams of the third color.

[0067] Figure 7-1 In the illustrated light source, the first color is blue, the second color is green, and the third color is red. The size of the red laser chip is larger than that of the blue and green laser chips. The fast and slow axis divergence angle ranges of the red laser are larger than those of the blue and green lasers. The slow axis divergence angle ranges of the red laser are larger than those of the blue and green lasers. For example, the size of the red laser chip is approximately 300 μm, while the sizes of the blue and green laser chips are approximately 70 μm. Furthermore, the slow axis divergence angle of the red laser is approximately 10 to 15 degrees, and the fast axis divergence angle is approximately 30 degrees. The fast and slow axis divergence angles of the blue and green lasers range from approximately 7 to 10 degrees. The collimating lens assembly of the laser assembly 110 is an integrated lens assembly. The collimating capabilities of each lens can be considered consistent, but the divergence angles of the three laser colors are different. Therefore, when three laser beams with different divergences are collimated through the same collimating lens, the collimation effects are also different. For example, the collimation effects of blue lasers and green lasers are similar, but because the red laser has a larger divergence, the parallelism of its collimated beam is less than that of the blue laser and the green laser. Therefore, the beam angle of the third color laser beam is greater than the angle of the first color and second color laser beams. And the third color laser beam is two laser beams, so the spot area of ​​the third color laser beam is larger. By placing the position where the second color laser beam and the first color laser beam are incident on the third light-combining lens 1203 between the two third color laser beams, the spot size of the combined beam is only equivalent to the spot size of the original third color laser beam, and the size of the combined beam will not increase due to the combination of beams of three color spot sizes.

[0068] And, in Figure 7-1In the light source shown, the first light-combining lens 1201a has a convex reflective surface, and the second light-combining lens 1202a also has a convex reflective surface, so that the beam angles of the first color and second color laser light beams can be increased respectively. In this way, the beam angles of the first color laser beam and the second color laser beam after increasing the convex surface reflection are closer to the third color laser beam, so that when the three colors of laser beams are combined, the uniformity of the combined light spot is better.

[0069] Figure 9-1 and Figure 9-2 A comparative example is given. The applicant found in practice that Figure 9-1 In the embodiment, when the first light combining mirror 1201a and the second light combining mirror 1201a both use a flat reflective surface for reflection, the beam angles of the first color laser beam and the second color laser beam after being reflected are both similar to the angles emitted from the light exiting surface of the laser assembly 110. When the three colors of laser light are combined by the third light combining mirror 1203a, the light spot on the incident surface of the light rod is analyzed, as shown in FIG. Figure 9-2 As shown in the figure, the spot distribution measured at the incident surface of the light rod shows a clear inner and outer color boundary. For example, the converging spot is approximately circular, with the outermost circle appearing red, followed by purple, blue, and other concentric circles inward. The above phenomenon shows that the combined color distribution of the three laser beams is uneven.

[0070] In an embodiment of the present application, by setting the light reflection surface of the light-combining lens corresponding to the first color laser beam and the second color laser beam as a convex reflection surface, the beam angles of the first color laser beam and the second color laser beam can be increased, making the beam angle closer to the beam angle of the third color laser beam with a larger beam angle, and the light spots of the first color laser beam and the second color laser beam are both superimposed within the light spot size of the third color laser beam. As a result, the color boundary phenomenon of the three-color laser light spot after light combination is alleviated, the overlap of the combined light spot is improved, the color uniformity is better, and the brightness is more uniform. The light source in the above example can provide a high-quality combined light beam.

[0071] In the above embodiment, the plurality of light-combining lenses 1201a, 1202a, and 1203a are each used to make a 90-degree turn of the light beams emitted from the corresponding light-emitting areas and then emit them in the direction of the light outlet of the light source. The plurality of light-combining lenses are arranged in sequence toward the light outlet of the laser light source, and at least one light-combining lens can transmit the light beams of the corresponding colors of the other light-emitting areas and combine them with the light beams reflected therefrom, and emit them in the direction of the light outlet of the laser light source. The spot sizes of the first-color laser beam and the second-color laser beam are both smaller than the spot size of the third-color laser beam, and the beam angles of the first-color laser beam and the second-color laser beam are different from the angles of the third-color laser beam. Specifically, the parallelism of the first-color laser beam and the second-color laser beam is both smaller than the parallelism of the third-color laser beam, that is, the divergence angle of the third-color laser beam is both greater than the divergence angle of the first-color laser beam and the second-color laser beam.

[0072] Figure 7-2 Another embodiment of a light source structure is shown, wherein the first light combining lens 1201b is used to receive the light beam emitted from the first light emitting area, the second light combining lens 1202b is used to receive the light beam emitted from the second light emitting area, and the third light combining lens 1203b is used to receive the light beam emitted from the third light emitting area.

[0073] The angles between the light-receiving surfaces of the first light-combining lens 1201b, the second light-combining lens 1202b, and the third light-combining lens 1203b and the first color laser beam, the second color laser beam, and the third color laser beam emitted from the light-emitting area of ​​the laser assembly 110 can all be set to 45°±2°, wherein the first light-combining lens 1201b is a reflector, and the second light-combining lens 1202b and the third light-combining lens 1203b are both dichroic mirrors. The first light-combining lens 1201b, the second light-combining lens 1202b, and the third light-combining lens 1203b are arranged parallel to each other.

[0074] First light-emitting region 1101 emits a first-color laser beam, and first light-combining lens 1201b functions as a reflector for reflecting the first-color laser beam. In one embodiment, the first-color laser beam is collimated by the collimating lens assembly upon exiting laser assembly 110 and can be considered a parallel or nearly parallel beam. This nearly parallel beam can still be considered a parallel or nearly parallel beam after being reflected by first light-combining lens 1201b.

[0075] Furthermore, the second light-emitting region 1102 emits a second-color laser beam. The second light-combining lens 1202b is configured to reflect the second-color laser beam and transmit the first-color laser beam, serving as a dichroic mirror. In one embodiment, the second-color laser beam is collimated by the collimating lens assembly upon exiting the laser assembly 110 and can be considered a parallel or nearly parallel beam. This nearly parallel beam can still be considered a parallel or nearly parallel beam after being reflected by the first light-combining lens 1201.

[0076] As well as Figure 7-2 As shown, the third light emitting area 1103 emits a third color laser, and the third light combining lens 1203b is used to reflect the third color laser beam and transmit the first color and second color laser beams.

[0077] like Figure 10 As shown, the third light-combining lens 1203b has a first surface 1203-1 and a second surface 1203-2, wherein the first surface 1203-1 has a raised microstructure, which is the incident surface of the first color laser beam and the second color laser beam. After the first color laser beam and the second color laser beam are transmitted through the raised microstructure, they are diverged to a certain extent due to the scattering effect of the microstructure, so that the beam angles of the first color laser beam and the second color laser beam are expanded.

[0078] In a specific embodiment, the raised microstructures are microstructures with random distribution and random particle size, so that the divergence angles of the first color laser beam and the second color laser beam are also random.

[0079] In a specific embodiment, the cross-section of the raised microstructures may be semicircular, triangular, arc-shaped, or platform-shaped, and the microstructures may be arranged regularly, such as in rows and columns.

[0080] Furthermore, the microstructure may also be an irregular granular structure.

[0081] Through the microstructure setting in the above specific embodiment, the beam angles of the first color laser beam and the second color laser beam are increased by 2° to 8°, and the spot sizes of the first color laser beam and the second color laser beam are still within the spot size range of the third color laser beam.

[0082] As well as Figure 10 As shown, the second surface 1203-2 of the third light-combining lens is a plane reflective surface. The laser beam of the third color is reflected by the second surface 1203-2 and emitted toward the light outlet of the light source. In addition, the laser beams of the first color and the second color are also emitted toward the light outlet of the light source after being transmitted through the first surface 1203-1.

[0083] In the MCL packaged laser of this example, the third color laser beam is a red laser beam, which is two rows or two columns. The third light-combining lens is used to receive two rows of red laser beams. Its size is larger than that of the first light-combining lens and the second light-combining lens, so that it can receive all the beams transmitted and reflected from the second light-combining lens.

[0084] In this example, the third light-emitting area 1103 emits two laser beams of the third color, the first light-emitting area 1101 emits one laser beam of the first color, and the second light-emitting area 1102 emits one laser beam of the second color. When these three laser beams of color illuminate the third light-combining lens 1203, preferably, the first and second laser beams of color enter the third light-combining lens 1203 between the two laser beams of the third color. The third light-combining lens 1203 is positioned near the light-emitting port.

[0085] And, in Figure 7-2 In the light source shown, the first surface of the third light-combining lens 1203b, i.e., the incident surface of the first color laser beam and the second color laser beam, has a raised microstructure, which can respectively expand the beam angle of the first color laser beam and the second color laser beam after transmission, thereby increasing the spot area of ​​the two beams, making the spot of the first color laser beam and the second color laser beam overlap better with the spot of the third color laser beam, and can reduce or eliminate the color boundary phenomenon of the light-combining spot, and the color uniformity of the light-combining spot is also better. The embodiment of the present application can also improve Figure 9-2 The light spot phenomenon shown.

[0086] In one specific implementation, the raised microstructure can be a diffusion component adhered to the first surface of the third light-combining lens, or the raised microstructure can be particles coated on the first surface of the third light-combining lens, or the raised microstructure can be formed on the first surface of the third light-combining lens by photolithography.

[0087] And, as a variation of the above embodiment, Figure 7-3 As shown, a diffusion component can be further provided before the first color laser beam and the second color laser beam enter the third light-combining lens.

[0088] In one embodiment, the diffusion component 1204 can also be disposed between the second light-combining lens 1202c and the third light-combining lens 1203c. The diffusion component 1204 can have a single-sided or double-sided microstructure to diffuse the light beams passing therethrough at different angles. In this way, the third light-combining lens 1203c can use a conventional dichroic mirror, which can reduce the manufacturing difficulty.

[0089] And, as another variation of the above embodiment, it is also possible to Figure 7-4As shown, before the first color laser beam and the second color laser beam enter the first light combining lens 1201d and the second light combining lens 1202d respectively, a diffusion component is set, and the diffusion component is set parallel to the first light exit area and the second light exit area, so that the first color laser beam and the second color laser beam are first diffused and then respectively reflected by the first light combining lens 1201d and the second light combining lens 1202d. In this example, the diffusion angle setting of the diffusion component 1205 can be less than Figure 7-3 The diffusion angle of the diffusion component 1204 is shown in FIG.

[0090] The diffusion component 1205 can be a diffusion sheet, or two diffusion sheets respectively provided for the first light exiting area and the second light exiting area.

[0091] In the light source structure provided in one or more of the above embodiments of the present application, the laser assembly has a first light exit area, a second light exit area, and a third light exit area, which respectively emit a first color laser beam, a second color laser beam, and a third color laser beam; a light combining lens group includes a plurality of light combining lenses, which are respectively arranged corresponding to the first light exit area, the second light exit area, and the third light exit area, and are used to combine the laser beams emitted from the above light exit areas and emit them to the light outlet of the light source. Wherein, the beam angles of the first color laser beam, the second color laser beam, and the beam angle of the third color laser beam after combining are greater than the beam angles directly emitted from the first light exit area and the second light exit area, and are both less than or equal to the beam angle of the third color laser beam. In some embodiments, when the first color laser beam and the second color laser beam are incident on or combined by the last light combining lens before the last light combining lens, the beam angles of the first color laser beam and the second color laser beam are increased by a convex reflector or a diffusion component, so that the area of ​​the spot size of the first color laser beam and the second color laser beam can be increased, and the difference in spot size with the original larger beam angle of the third color laser beam can be reduced.

[0092] The light spots of the first and second color laser beams are superimposed within the spot size of the third color laser beam. This reduces the color boundary phenomenon of the three-color laser spot after the combined light beam, improves the color uniformity of the combined light spot, and makes the brightness more uniform. The light source in the above example can provide a high-quality combined light beam.

[0093] The laser projection device provided in the above embodiment of the present application uses a laser assembly that emits three colors of laser light, and the three colors of laser light are arranged in rows or columns. The wavelengths of the three colors are different, wherein the wavelength of the first color and the wavelength of the second color are both smaller than the wavelength of the third color. By increasing the angles of the first color laser beam and the second color laser beam before combining with the third color laser beam, the difference in angle and spot size with the third color laser beam is reduced. When the three colors of laser light are combined, the overlap of the combined light spot is improved, the phenomenon of spot aperture boundary is reduced or eliminated, and the color uniformity is improved. At the same time, the brightness uniformity can also be improved accordingly, which also improves the display quality of the projected image.

[0094] 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 them. 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser projection device, characterized in that: including a light source for providing an illumination beam; an optical machine, configured to modulate the illumination light beam; A lens, used for receiving the modulated illumination light beam for projecting imaging; The light source comprises: A laser assembly having a first light emitting area, a second light emitting area, and a third light emitting area, emitting a first color laser beam, a second color laser beam, and a third color laser beam, respectively; wherein a divergence angle of the third color laser beam is greater than a divergence angle of the first color laser beam and a divergence angle of the second color laser beam, and a spot area of ​​the first color laser beam and the second color laser beam is smaller than a spot area of ​​the third color laser beam; The first light emitting area, the second light emitting area, and the third light emitting area are located on the same laser component; a light combining lens assembly, comprising a plurality of light combining lenses, respectively arranged corresponding to the first light exit area, the second light exit area, and the third light exit area, for combining the laser beams emitted from the above light exit areas and emitting them out of the light source outlet; The first color laser beam and the second color laser beam pass through a diffusion component before being combined with the third color laser beam. The light combining lens group includes a plurality of light combining lenses arranged on the outgoing light path of the light exit area emitting the corresponding color laser beam; wherein, the light combining lens arranged corresponding to the third light exit area is a dichroic lens and is arranged close to the light outlet of the light source.

2. The laser projection device according to claim 1, characterized in that: The diffusion component is arranged parallel to the first light exiting area and the second light exiting area.

3. The laser projection device according to claim 1 or 2, characterized in that: The light combining lens group includes a first light combining lens, a second light combining lens, and a third light combining lens, which are respectively arranged corresponding to the first light emitting area, the second light emitting area, and the third light emitting area; The first light-combining lens, the second light-combining lens and the third light-combining lens are arranged parallel to each other, and the light receiving surfaces of the first light-combining lens, the second light-combining lens and the third light-combining lens are all arranged at an angle to the corresponding light-emitting areas.

4. The laser projection device according to claim 3, characterized in that: The diffusion component is located between the first light exit area and the first light combining lens, and / or the diffusion component is located between the second light exit area and the second light combining lens.

5. The laser projection device according to claim 3, characterized in that: The first light-combining lens is used to reflect the first color laser beam to the second light-combining lens; the second light-combining lens is used to transmit the first color laser beam and reflect the second color laser beam to the third light-combining lens; the third light-combining lens is used to transmit the first color laser beam and the second color laser beam, and reflect the third color laser to the laser light source outlet.

6. The laser projection device according to any one of claims 1-2, 4, and 5, characterized in that: The first light exiting area, the second light exiting area, and the third light exiting area are arranged adjacent to each other in sequence, and an area of ​​the third light exiting area is larger than an area of ​​the first light exiting area and the second light exiting area.

7. The laser projection device according to claim 6, characterized in that: The laser assembly includes a substrate and a plurality of light-emitting chips, wherein the plurality of light-emitting chips are arranged in an array, wherein one row emits blue laser, one row emits green laser, and two rows emit red laser.

8. The laser projection device according to claim 6, characterized in that: The first color is blue, the second color is green, and the third color is red.

9. The laser projection device according to claim 1, characterized in that: The light source includes a light source shell, which has a accommodating cavity. The laser assembly and the light combining mirror assembly are at least partially accommodated in the accommodating cavity. The accommodating cavity has an opening along the light emitting direction of the light source. A focusing lens is provided at the opening, and a diffusion portion is provided on the light emitting path of the focusing lens.

10. The laser projection device according to claim 9, characterized in that: The diffusion part is a rotating diffusion sheet.

11. The laser projection device according to claim 9 or 10, characterized in that: The light beam diffused by the diffusion part is incident on a light homogenizing component, which includes a light rod or a fly-eye lens group.

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