Laser illumination module, optical projection system and intelligent head-mounted device

Abstract

The embodiment of the invention provides a laser illumination module, an optical projection system and intelligent head-mounted equipment. The laser illumination module comprises a first lens group, a fly eye lens, a second lens group, a reflector, an internal total reflection prism and a DMD chip. The first lens group comprises at least one of a first lens and a second lens and a diffusion sheet; the fly-eye lens is located on the light emitting side of the first lens group; the second lens group comprises a third lens and a fourth lens; the reflecting mirror is positioned on a light path between the third lens and the fourth lens; the internal total reflection prism is positioned on the light emitting side of the fourth lens; the DMD chip and the internal total reflection prism are arranged adjacently; the fourth lens can move along the optical axis of the fourth lens so as to change the interval between the fourth lens and the third lens and the interval between the fourth lens and the internal total reflection prism, and therefore zooming is achieved. And the DMD chip receives the zoomed illumination light, so that the laser illumination module can be matched with DMD chips with different sizes.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical display technology. More specifically, the embodiments of the present application relate to a laser lighting module, an optical projection system, and an intelligent head-mounted device. Background Art

[0002] With the rapid development of the projection product market, laser projectors have gradually gained wide popularity among consumers for their advantages such as bright colors, high color gamut, and compact size. As the core component of laser projectors, the laser lighting module has a high degree of design complexity, which directly affects the key indicators of laser projectors such as luminous flux, contrast, and picture uniformity. Among them, DMD (digital micromirror device, or light valve) is the main component of the laser lighting module. Its size, micromirror deflection angle and other parameters determine the design of the relay system of the lighting module, such as the curvature radius, thickness and spacing of the lens.

[0003] However, due to the wide variety of DMD types and models, laser illumination modules also present diversified characteristics. This not only increases the R&D cost, but also makes it difficult to share laser illumination modules between platforms, resulting in repeated waste of resources. Therefore, how to solve the problem of a large number of laser illumination modules and their incompatibility and sharing has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0004] The purpose of this application is to provide a new technical solution for a laser lighting module, an optical projection system and an intelligent head-mounted device.

[0005] In a first aspect, the present application provides a laser lighting module, the laser lighting module comprising:

[0006] A first lens group includes at least one of a first lens and a second lens, and a diffusion sheet;

[0007] A fly-eye lens, located at the light-emitting side of the first lens group;

[0008] The second lens group includes a third lens and a fourth lens;

[0009] a reflector, located on the optical path between the third lens and the fourth lens, and used for changing the direction of the optical path;

[0010] An internal total reflection prism, located at the light exiting side of the fourth lens;

[0011] A DMD chip is arranged adjacent to the total internal reflection prism;

[0012] The fourth lens can be moved along its optical axis to change the interval between it, the third lens and the total internal reflection prism, thereby achieving zooming;

[0013] The DMD chip receives the zoomed illumination light, so that the laser illumination module can match DMD chips of different sizes.

[0014] Optionally, the laser illumination module satisfies: 1.2≤|f1 / f2|≤1.5; wherein f1 and f2 are the focal lengths of the laser illumination module corresponding to when the DMD chip is 0.39 inches and 0.47 inches, respectively.

[0015] Optionally, when the first lens group includes a first lens and a second lens, the diffusion sheet is located between the first lens and the second lens.

[0016] Optionally, the first lens, the second lens, the third lens and the fourth lens are glass spherical lenses.

[0017] Optionally, when the DMD chip is 0.39 inches, the F number of the laser illumination module is F1, and when the DMD chip is 0.47 inches, the F number of the laser illumination module is F2, and F1<F2.

[0018] Optionally, when the DMD chip is 0.39 inches, the optical effective aperture of the fourth lens is D1; ​​when the DMD chip is 0.47 inches, the optical effective aperture of the fourth lens is D2, and D1=D2.

[0019] Optionally, the optical power of the first lens, the second lens, the third lens and the fourth lens are all positive.

[0020] Optionally, the first lens is a convex-concave lens, the second lens is a concave-convex lens, and the third lens and the fourth lens are biconvex lenses.

[0021] Optionally, the compound eye lens is a double-sided compound eye, the incident light angle is ≤10°, and the thickness is ≤5mm.

[0022] Optionally, the first lens, the second lens and the third lens are arranged along a first optical axis, the fourth lens is arranged along the second optical axis, and the first optical axis and the second optical axis form an angle;

[0023] The reflector is tilted to project the light emitted from the third lens to the fourth lens.

[0024] Optionally, the second lens group further includes a fifth lens, and the fifth lens is located between the third lens and the fourth lens.

[0025] Optionally, the lighting module further includes a laser light source located on the light incident side of the first lens group.

[0026] In a second aspect, the present application provides an optical projection system, the optical projection system comprising:

[0027] The laser illumination module as described in the first aspect; and

[0028] A projection lens is located at the light-emitting side of the total internal reflection prism.

[0029] In a third aspect, the present application provides a smart head-mounted device, the smart head-mounted device comprising:

[0030] casing; and

[0031] An optical projection system as described in the second aspect.

[0032] The beneficial effects of this application are:

[0033] In response to the problems existing in the prior art, the embodiments of the present application propose a laser illumination module with variable focus and compatible with DMD chips of different sizes. The laser illumination module of the present application can flexibly change the spot size and incident angle of the light incident to the DMD chip by adjusting the focal length of the relay part, thereby achieving compatibility with DMD chips of different sizes, significantly improving the degree of commonality of laser projection products, and effectively reducing development and manufacturing costs.

[0034] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0036] Figure 1 A schematic diagram of the structure of an optical projection system provided in an embodiment of the present application;

[0037] Figure 2 A simulation diagram of an optical projection system provided in an embodiment of the present application;

[0038] Figure 3 A comparison diagram of the system layout of the optical projection system provided in an embodiment of the present application with a DMD chip having a size of 0.47 inches (left side) and a DMD chip having a size of 0.39 inches (right side);

[0039] Figure 4 for Figure 3 The dot array diagram of the optical projection system under the 0.47-inch DMD chip is shown on the left side;

[0040] Figure 5 for Figure 3The dot array diagram of the optical projection system under the 0.39-inch DMD chip is shown on the right side;

[0041] Figure 6 A light trace diagram of the image plane of the laser illumination module of an embodiment of the present application;

[0042] Figure 7 for Figure 3 The relative illumination diagram of the optical projection system under a 0.47-inch DMD chip is shown on the left side;

[0043] Figure 8 for Figure 3 The right side of the figure shows the relative illumination diagram of the optical projection system under the 0.39-inch DMD chip.

[0044] Description of reference numerals:

[0045] 100. Laser light source;

[0046] 201, first lens; 202, second lens; 203, diffuser; 204, fly-eye lens; 205, third lens; 206, reflector; 207, fourth lens; 208, internal total reflection prism; 209, DMD chip;

[0047] 300. Projection lens. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0049] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0050] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0051] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0052] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] The laser illumination module, optical projection system and intelligent head-mounted device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0054] According to an embodiment of the present application, a laser illumination module is provided. Figure 1 and Figure 2 The laser illumination module includes a first lens group, a fly-eye lens 204, a second lens group, a reflector 206, an internal total reflection prism 208 and a DMD chip 209; the first lens group includes at least one of a first lens 201 and a second lens 202, and a diffuser 203; the fly-eye lens 204 is located at the light exit side of the first lens group; the second lens group includes a third lens 205 and a fourth lens 207; the reflector 206 is located in the optical path between the third lens 205 and the fourth lens 207 on, used to change the direction of the light path; the internal total reflection prism 208 is located on the light-emitting side of the fourth lens 207; the DMD chip 209 is arranged adjacent to the internal total reflection prism 208; wherein the fourth lens 207 can move along its optical axis to change the interval between it and the third lens 205 and the internal total reflection prism 208, thereby achieving zooming; the DMD chip 209 receives the zoomed illumination light, so that the laser illumination module can match DMD chips 209 of different sizes.

[0055] The laser illumination module provided in the embodiment of the present application realizes the zoom function of the relay part through a specially designed optical path layout, and the entire laser illumination module can realize the function of being compatible with DMD chips 209 of different sizes. The laser illumination module provided in the embodiment of the present application is composed of multiple key optical components, and the main optical components involved are described below.

[0056] The laser illumination module provided in the embodiment of the present application includes a first lens group arranged adjacent to the laser light source 100 on the light incident side, see Figure 1 and Figure 2 The first lens group may include 1 to 2 lenses. For example, the first lens group may include only the first lens 201, or only the second lens 202, or both the first lens 201 and the second lens 202. The number of lenses may be flexibly adjusted as needed.

[0057] The first lens group further includes a diffuser 203 , which is, for example, a vibration diffuser.

[0058] The combination of the first lens group preliminarily shapes and amplifies the illumination light (laser light) emitted by the laser light source 100, while the diffuser 203 effectively suppresses laser speckle to ensure the uniformity and quality of the light.

[0059] The laser illumination module provided in the embodiment of the present application includes a fly-eye lens 204 located behind the first lens group, and the fly-eye lens 204 is used to further homogenize and shape the incident illumination light, so that the illumination light is more uniform and consistent, providing a good foundation for subsequent precise control.

[0060] The fly-eye lens 204 may be, for example, a double-sided fly-eye.

[0061] The laser illumination module provided in the embodiment of the present application includes a second lens group, and the second lens group may include 2 to 3 lenses. Figure 1 and Figure 2 , the second lens group is mainly composed of a third lens 205 and a fourth lens 207. This combination relays and regulates the illumination light homogenized by the fly-eye lens 204, ensuring that the illumination light can be accurately incident on the DMD chip 209. Among them, the reflector 206 is cleverly located on the optical path between the third lens 205 and the fourth lens 207, and is used to change the direction of the optical path, making the entire optical path layout more compact and reasonable.

[0062] The laser illumination module provided in the embodiment of the present application includes an internal total reflection prism 208, see Figure 1 and Figure 2 The internal total reflection prism 208 is located on the light-emitting side of the fourth lens 207. It utilizes the total reflection principle to effectively separate the illumination light incident on the DMD chip 209 from the projection light entering the projection lens 300, thereby avoiding mutual interference of the light.

[0063] In the laser illumination module provided in the embodiment of the present application, the most critical thing is that the fourth lens 207 is designed to be movable along its optical axis to change the interval between it and the third lens 205 and the total internal reflection prism 208. This design realizes the zoom function of the relay part. By adjusting the focal length, the spot size and the angle of light incident on the DMD chip 209 can be changed, so as to match the DMD chips 209 of different sizes. This design not only improves the universality and modularity of laser projection equipment, but also significantly reduces the development and manufacturing costs.

[0064] It is worth noting that see Figure 3In the present application, the third lens 205, the fourth lens 207 and the reflector 206 located between them together constitute the relay optical path in the entire lighting module. The main function of this optical path is to shape the illumination light incident on the DMD chip 209 (image processing chip) and adjust its incident angle. In this process, the third lens 205 first performs preliminary shaping on the illumination light, and then the illumination light is reflected by the reflector 206, and then further regulated by the fourth lens 207 to ensure that the illumination light can be projected onto the DMD chip 209 in the best state. At the same time, the internal total reflection prism 208 plays an important role. It separates the illumination light incident on the DMD chip 209 from the light beam entering the projection lens 300, avoiding interference between the two. As the core component of image processing, the DMD chip 209 performs the final regulation of the illumination light through millions of precise micro-mirrors inside it, thereby achieving high-quality output of the image.

[0065] The laser illumination module provided in the embodiment of the present application can process the illumination light emitted by the external laser light source 100 and then project it to the projection lens 300.

[0066] The laser illumination module provided in the embodiment of the present application realizes the zoom function of the module by moving the fourth lens 207 along its optical axis to change the interval between it and the third lens 205 and the total internal reflection prism 208. This zoom function enables the laser illumination module to match DMD chips 209 of different sizes, thereby improving the compatibility and flexibility of the module. The laser illumination module of the embodiment of the present application is compatible with DMD chips of various sizes such as 0.39 inches and 0.47 inches. The improvement in compatibility reduces the R&D cost and avoids the need to redesign the illumination module for different DMD chips.

[0067] In the laser illumination module provided in the embodiment of the present application, the first lens group, the second lens group, the fly-eye lens 204, the reflector 206, the internal total reflection prism 208 and the DMD chip 209 work together to achieve precise control of the light path. Precise light path control ensures that light can be efficiently and accurately projected onto the DMD chip 209, thereby improving image quality.

[0068] The compound eye lens 204 homogenizes and shapes the incident illumination light, thereby improving the uniformity and consistency of the illumination effect. All components such as lenses and reflectors 206 in the laser illumination module are carefully designed to ensure the best transmission and projection effect of the light.

[0069] It should be noted that, in the design of the present application, the fourth lens 207 can be moved along its optical axis to change the interval between it, the third lens 205 and the internal total reflection prism 208, so as to achieve zooming. Figure 1 and Figure 2 , the fourth lens 207 and the third lens 205 are not located on the same optical axis, and the distance between the two refers to the straight-line distance from the center of the fourth lens 207 to the center of the third lens 205. The distance between the fourth lens 207 and the total internal reflection prism 208 refers to the air distance between the two.

[0070] In summary, this application reduces the cost of redeveloping laser lighting modules for different products by achieving zoom and compatibility with a variety of DMD chips. The laser lighting module of this application has improved commonality and modularity, simplifying the production and maintenance process. R&D personnel can quickly develop a variety of laser projection products of different sizes based on the laser lighting module. The versatility of the laser lighting module of this application reduces the workload of repeated design and improves R&D efficiency.

[0071] In some examples of the present application, the laser illumination module satisfies: 1.2≤|f1 / f2|≤1.5; wherein f1 and f2 are the focal lengths of the laser illumination module corresponding to when the DMD chip 209 is 0.39 inches and 0.47 inches, respectively.

[0072] The setting of the focal length ratio range proposed in this example of the present application is described in detail as follows.

[0073] By setting the focal length ratio range between 1.2 and 1.5 (including the two endpoint values ​​of 1.2 and 1.5), it is ensured that when the size of the DMD chip 209 is switched from 0.39 inches to 0.47 inches, the laser illumination module provided in the embodiment of the present application can maintain a certain zoom capability and optical performance stability.

[0074] Within the focal length ratio range mentioned in this example of the present application, by adjusting the position of the relay part of the laser illumination module, such as the fourth lens 207, corresponding changes in the spot size and the incident angle can be achieved, thereby meeting the illumination requirements of DMD chips 209 of different sizes.

[0075] In addition, the setting of the focal length ratio range in this example of the present application also takes into account the balance of optical performance, including key indicators such as illumination uniformity, spot size control, and telecentricity, to ensure that image quality is not affected.

[0076] In the structure of the laser illumination module provided in the embodiment of the present application, four lenses (such as the first lens 201, the second lens 202, the third lens 205 and the fourth lens 207) and the fly-eye lens 204 play a vital role. They are mainly responsible for regulating the illumination light incident on the surface of the DMD chip 209 (digital micromirror device), including the precise adjustment of the size of the light spot and the incident angle. Therefore, when the DMD chip 209 needs to be replaced, for example, from 0.47 inches to 0.39 inches (or other inches such as 0.65 inches), due to the different requirements of the DMD chips 209 of different sizes for the incident illumination light, it is usually necessary to redesign each lens and the fly-eye lens 204 to ensure that the illumination light can be accurately projected onto the surface of the DMD chip 209 and meet its specific optical performance requirements.

[0077] In this example of the present application, the design optimization is particularly carried out for the compatible laser illumination module of the 0.39-inch and 0.47-inch DMD chips 209. Figure 3 As shown, the relay optical path of the laser illumination module is mainly improved. Under the premise of maintaining full compatibility between the compound eye lens 204 and four lenses (such as the first lens 201, the second lens 202, the third lens 205 and the fourth lens 207), by adjusting the spacing between the fourth lens 207 and other lenses (such as the third lens 205) and the internal total reflection prism 208, a zoom function of about 1.2 times of the laser illumination optical path is achieved. This zoom function can flexibly change the area and incident angle of the spot, thereby meeting the different requirements of the 0.39-inch and 0.47-inch DMD chips 209 for the incident illumination light. In short, by accurately adjusting the position of the fourth lens 207, it can be ensured that the illumination light can maintain the best optical performance when projected onto DMD chips 209 of different sizes, including high illumination uniformity, small spot size and precise incident angle.

[0078] The design in this example of the present application enables the laser lighting module to be more compatible with DMD chips 209 of two sizes, 0.39 inches and 0.47 inches, reducing the dependence on specific DMD chips and improving the versatility and flexibility of the laser lighting module. By controlling the focal length ratio range, a more precise zoom effect is achieved, and the adaptability and performance of the laser lighting module in different application scenarios are improved. When adjusting the zoom within the focal length ratio range, the optical performance can be kept relatively stable, ensuring that the image quality is not affected by the zoom operation.

[0079] In some examples of this application, see Figure 1 and Figure 2When the first lens group includes a first lens 201 and a second lens 202 , the diffusion sheet 203 is located between the first lens 201 and the second lens 202 .

[0080] The main function of the diffuser 203 is to suppress laser speckle, that is, to reduce or eliminate interference patterns caused by the coherence generated by the laser light source 100. These patterns may appear as bright and dark spots on the projection screen, affecting the visual effect.

[0081] The diffusion sheet 203 is, for example, a vibration diffusion sheet.

[0082] The diffuser 203 is placed between the first lens 201 and the second lens 202 based on comprehensive considerations of optical path design and speckle suppression effect. This position can ensure that the illumination light emitted by the laser light source 100, that is, the laser light, is focused or collimated to a certain extent before passing through the diffuser 203 for speckle suppression, thereby more effectively reducing the generation of interference patterns.

[0083] In one example, see Figure 1 and Figure 2 The first lens group includes a first lens 201 and a second lens 202 spaced apart along the same optical axis. The main function of the combination of these two lenses is to shape the light beam and adjust the angle, in preparation for subsequent homogenization and projection. The addition of the diffuser 203 will not only not destroy this function, but can improve the optical performance of the entire laser illumination module, especially in terms of suppressing speckle.

[0084] By suppressing laser speckle, the uniformity and clarity of the projected image can be significantly improved, and the visual interference caused by the interference pattern can be reduced. This design enables the laser illumination module of the present application to be applicable to more types of DMD chips, because speckle suppression is one of the key factors in improving image quality and is equally important for DMD chips of different sizes.

[0085] In summary, when the first lens group includes the first lens 201 and the second lens 202, the design of locating the diffuser 203 between the first lens 201 and the second lens 202 has significant technical effects in improving image quality, enhancing compatibility, optimizing light effects, and simplifying optical path design.

[0086] It should be noted that, when only one lens is used in the first lens group, the lens may be the first lens 201 or the second lens 202 .

[0087] For example, the first lens group includes a first lens 201 and a diffuser 203 , and the diffuser 203 is placed between the light-emitting side of the first lens 201 and the fly-eye lens 204 .

[0088] For another example, the first lens assembly includes a second lens 202 and a diffuser 203 , and the diffuser 203 is placed between the laser light source 100 and the second lens 202 .

[0089] In some examples of the present application, the first lens 201 , the second lens 202 , the third lens 205 , and the fourth lens 207 are glass spherical lenses.

[0090] Compared with aspherical lenses, glass spherical lenses have lower manufacturing costs because the processing and inspection process of spherical lenses is relatively simple. Glass materials have excellent optical properties and stability, can withstand high temperatures and pressures, and are suitable for high-power laser projection systems.

[0091] In the laser illumination module provided in the embodiment of the present application, all lenses (such as the first lens 201, the second lens 202, the third lens 205 and the fourth lens 207) are spherical. Compared with the existing solution that usually has only one spherical lens and the others are aspherical lenses, the design of the present application can significantly reduce the production cost.

[0092] In the present application, although all lenses are of spherical design, high imaging quality and picture uniformity can still be achieved through precise optical path layout and lens parameter selection.

[0093] Of course, without considering the cost, all lenses in the laser illumination module provided in the embodiment of the present application may also be made of glass aspherical lenses.

[0094] In some examples of the present application, when the DMD chip 209 is 0.39 inches, the F number of the laser illumination module is F1, and when the DMD chip 209 is 0.47 inches, the F number of the laser illumination module is F2, and F1<F2.

[0095] The F number (also called the aperture number) is the ratio of the focal length to the entrance pupil diameter in an optical system, which determines the system's luminous flux and depth of field. The smaller the F number, the greater the luminous flux and the shallower the depth of field; the larger the F number, the smaller the luminous flux and the deeper the depth of field.

[0096] The DMD chip is a core device in laser projection products, and its size determines the design of the relay part of the lighting module. As the size of the DMD chip 209 increases, in order to maintain the same lighting uniformity and spot size, it is usually necessary to increase the focal length of the relay part, resulting in an increase in the F number.

[0097] In the present application, when the size of the DMD chip 209 is small (such as 0.39 inches), a larger luminous flux is required to obtain sufficient brightness and contrast. Therefore, selecting a smaller F number (F1) can increase the luminous flux and ensure the lighting quality. When the size of the DMD chip 209 is large (such as 0.47 inches), although the luminous flux requirement is relatively low, in order to ensure lighting uniformity and reduce spot distortion, it is necessary to increase the focal length and increase the F number (F2) accordingly.

[0098] For example, the size of the DMD chip 209 is 0.39 inches, and F1 is 2.0; the size of the DMD chip 209 is 0.47, and F2 is 2.4.

[0099] The laser lighting module provided in the embodiment of the present application has a zoom function, and can be compatible with DMD chips 209 of different sizes by adjusting the focal length of the relay part. The different designs of F1 and F2 ensure that the best lighting effect can be obtained under different DMD chip sizes. By selecting the appropriate F number for DMD chips of different sizes, it can be ensured that the best lighting quality and picture uniformity can be obtained in any case. The smaller F number (F1) provides a larger luminous flux when the DMD chip size is small, which helps to improve the overall light effect and brightness.

[0100] In some examples of the present application, when the DMD chip 209 is 0.39 inches, the optical effective aperture of the fourth lens 207 is D1; ​​when the DMD chip 209 is 0.47 inches, the optical effective aperture of the fourth lens 207 is D2, and D1=D2.

[0101] By keeping the optical effective aperture of the fourth lens 207 consistent under different DMD chip sizes (D1=D2), this design enables the laser illumination module to be compatible with DMD chips of different sizes, such as 0.39 inches and 0.47 inches, without replacing the lens.

[0102] This compatibility reduces module redesign and manufacturing costs due to DMD chip replacement. The unified lens design reduces the complexity of production and inventory management. Since there is no need to customize lenses of different calibers for DMD chips of different sizes, material costs and manufacturing costs can be saved. Designers do not need to develop multiple lens specifications for different DMD chip sizes, which simplifies the design process.

[0103] Maintaining the consistency of the lens's optical effective aperture helps ensure that the optical performance of the laser illumination module (such as spot size, incident angle, relative illumination, etc.) remains consistent under different DMD chip sizes. This helps improve the quality and consistency of the final projected image.

[0104] In some examples of the present application, the optical powers of the first lens 201 , the second lens 202 , the third lens 205 , and the fourth lens 207 are all positive.

[0105] A lens with positive focal length has the characteristic of converging light. Therefore, when the focal lengths of the four lenses in the laser illumination module are all positive, they can more effectively converge the light emitted by the laser light source 100 and guide it to the DMD chip 209, thereby improving the utilization rate of light and the brightness of the projected image.

[0106] In the laser illumination module provided in the present application, four lenses with positive optical power can work together on the incident illumination light to achieve the shaping and angle control of the illumination light. This is crucial to ensure that the light is incident on the DMD chip 209 at an appropriate angle and size, which helps to optimize the uniformity and contrast of the projected image.

[0107] The combination of positive optical power lenses helps reduce the loss and distortion of light during transmission, thereby improving the stability and reliability of the entire laser illumination module. This is essential to ensure the clarity and stability of the projected image. In addition, the use of a lens combination with positive optical power can simplify the design process because there is no need to consider the complex combination and correction issues between lenses with different optical powers.

[0108] In some examples of this application, see Figure 1 The first lens 201 is a convex-concave lens, the second lens 202 is a concave-convex lens, and the third lens 205 and the fourth lens 207 are biconvex lenses.

[0109] The first lens 201 is a convex-concave lens, and one side close to the laser light source 100 is convex, and the other side is concave. The second lens 202 is a concave-convex lens, and one side close to the laser light source 100 is concave, and the other side is convex. The third lens 205 and the fourth lens 207 are both biconvex lenses, that is, both sides are convex.

[0110] The first lens 201 (convex-concave lens): its convex surface is used to converge light, and its concave surface may be used to adjust the divergence angle of light or perform aberration correction. This combination helps to effectively shape and pre-regulate light in the initial stage.

[0111] The second lens 202 (convex-concave lens): having a surface design opposite to that of the first lens 201, may be used to further adjust the path and angle of the light to achieve more precise light beam control.

[0112] The third lens 205 and the fourth lens 207 (double convex lens): The double convex design significantly enhances the ability to converge light, which helps to further converge the light shaped by the first two lenses and guide it to the DMD chip 209. By adjusting the relative position or spacing between the fourth lens 207 and the third lens 205 and the total internal reflection prism 208, the zoom function can be achieved to a certain extent. In particular, when it is necessary to be compatible with DMD chips of different sizes, the zoom function is particularly important.

[0113] In this example of the present application, different lens surface combinations help correct various aberrations, such as spherical aberration, coma, astigmatism, etc. The clarity and quality of the projected image can be significantly improved through specially designed lens surface shapes and combinations. The use of these specific lens surface combinations in this example of the present application helps reduce the loss and distortion of light during transmission, which helps improve the stability and reliability of the entire laser lighting module, thereby ensuring the stability and consistency of the projected image.

[0114] In some examples of the present application, the fly-eye lens 204 is a double-sided fly-eye, the incident light angle of which is ≤10° and the thickness of which is ≤5 mm.

[0115] The double-sided compound eye design can effectively homogenize and shape the incident illumination light. The compound eye lens is composed of many small lens units, each of which can make fine adjustments to the light, making the entire light spot more uniform and reducing the uneven brightness of the light.

[0116] Limiting the incident light angle to ≤10° helps ensure that the light enters the compound eye at an appropriate angle, avoiding light loss or distortion caused by excessive angles. This helps maintain the quality of the light and improves the clarity of the projected image. In addition, this incident light angle restriction is also conducive to optimizing the design of the compound eye lens.

[0117] The thickness of the fly-eye lens 204 ≤ 5 mm helps to reduce the volume and weight of the entire optical system, making the laser illumination module more compact and lightweight.

[0118] In some examples of this application, see Figure 1 and Figure 2 The first lens 201, the second lens 202 and the third lens 205 are arranged along the first optical axis, the fourth lens 207 is arranged along the second optical axis, and the first optical axis and the second optical axis form an angle; the reflector 206 is tilted to project the light emitted by the third lens 205 to the fourth lens 207.

[0119] In the present application, the first lens 201, the second lens 202 and the third lens 205 are arranged along the first optical axis, and the fourth lens 207 is arranged along the second optical axis, and the second optical axis forms a certain angle with the first optical axis. The reflector 206 located between the third lens 205 and the fourth lens 207 is arranged at an angle, and its position and function are to reflect the light emitted by the third lens 205 and project it to the fourth lens 207, thereby realizing the turning and expansion of the light path.

[0120] By providing the reflector 206, the turning of the optical path is successfully achieved, so that the light originally transmitted along the first optical axis can change direction and continue to be transmitted along the second optical axis. This not only saves space, but also makes the layout of the optical system more flexible and compact.

[0121] The reflector 206 is tilted to prevent light from directly hitting the edge or corner of the mirror surface, reducing light loss and distortion caused by mirror damage or contamination. At the same time, this layout also helps to improve the stability and reliability of the entire optical system, ensuring that the system can maintain stable performance during long-term operation.

[0122] It should be noted that see Figure 1 and Figure 2 The side edges of the fourth lens 207 and the internal total reflection prism 208 adjacent thereto are, for example, arranged in parallel. Of course, in actual production, the side edges of the fourth lens 207 and the internal total reflection prism 208 adjacent thereto may also form an angle within 2°, for example.

[0123] In some examples of the present application, the second lens group further includes a fifth lens, and the fifth lens is located between the third lens 205 and the fourth lens 207 .

[0124] In this example of the present application, a fifth lens can be added to the second lens group. This fifth lens can be designed to be located between the third lens 205 and the fourth lens 207, that is, after the light is emitted from the third lens 205, it can first pass through the fifth lens, and then be reflected to the fourth lens 207 by the reflector 206. The addition of the fifth lens provides more control means for the light path, and can further optimize the shape, size and angle of the light spot to meet the lighting requirements of different DMD chips 209. In addition, in the zoom laser lighting module, the addition of the fifth lens may help to expand the zoom range, so that the module can be compatible with more types of DMD chips.

[0125] In some examples of the present application, the lighting module further includes a laser light source 100 located on the light incident side of the first lens group.

[0126] The laser light source 100 serves as the light source of the entire laser lighting module, providing lighting light for subsequent optical components. The laser light source 100 has the advantages of high brightness, high color saturation, and long life, and can significantly improve the light efficiency and performance of the lighting module. Since the laser light source has good stability, the system stability of the entire lighting module will also be improved accordingly. In addition, the addition of the laser light source enables the lighting module to be applicable to more types of application scenarios.

[0127] See also Figure 4 and Figure 5 , Figure 4 and Figure 5 The dot array diagrams (Spot diagrams) of the DMD chip 209 are 0.39 inches and 0.47 inches respectively, and the RMS (root mean square) spot radius is less than 103 microns, which indicates that the light is well focused and the light energy can be efficiently used.

[0128] Figure 6 The light trace diagram of the image plane of the laser illumination module of the embodiment of the present application is shown. Figure 6 It can be clearly seen that the laser illumination module can well meet the spot size requirements of incident on 0.39-inch and 0.47-inch DMD chips 209, thereby achieving compatibility with DMD chips of different sizes.

[0129] Figure 7 and Figure 8 The relative illumination diagrams of the laser lighting modules with DMD chips 209 of 0.47 inches and 0.39 inches are shown respectively. Figure 7 It can be seen that the relative illumination remains almost constant in the entire field of view, close to 1.0, which indicates that the illumination is very uniform in the entire field of view, with no obvious uneven illumination. Figure 8 It can be seen that the relative illumination remains almost unchanged in the entire field of view, close to 1.0, which further shows that the illumination is very uniform within this field of view.

[0130] In one example, the optical parameter design of the laser illumination module of the present application is shown in Tables 1 and 2 below; Table 1 is a design index table of the laser illumination module, and Table 2 is an optical parameter table.

[0131] Table 1

[0132]

[0133]

[0134] Table 2

[0135]

[0136] Referring to Table 2, before and after the fourth lens 207 is moved, the distances between the center of the fourth lens 207 and the centers of the third lens 205 and the total internal reflection prism 208 will change.

[0137] Specifically, surface number 9 shown in Table 2 shows that after the fourth lens 207 moves, the distance between its center and the center of the third lens 205 changes by 1 mm. Please continue to refer to Table 1, surface number 11 shows that after the fourth lens 207 moves, the distance between its center and the internal total reflection prism 208 changes by 1 mm. The above changes enable the laser illumination module of the present application to take into account both 0.39-inch DMD chips and 0.47-inch DMD chips.

[0138] According to another embodiment of the present application, an optical projection system is provided. Figure 1 The optical projection system includes the laser illumination module and the projection lens 300 as described above. The projection lens 300 is located on the light emitting side of the internal total reflection prism 208 .

[0139] This embodiment provides an optical projection system, which mainly includes two parts: one is the laser illumination module as described above, and the other is a projection lens 300 located on the light-emitting side of the laser illumination module. The laser illumination module is responsible for generating and regulating illumination light to meet the illumination requirements of the DMD chip 209 (digital micromirror device), while the projection lens 300 is responsible for amplifying the image light reflected from the DMD chip 209 and projecting it onto the screen.

[0140] The specific structure and working principle of the laser illumination module have been described in detail above. Among them, the design of the relay optical path is particularly critical, which can realize the zoom function and thus be compatible with DMD chips 209 of different sizes, such as 0.39 inches and 0.47 inches.

[0141] The projection lens 300 is located at the light-emitting side of the internal total reflection prism 208, and is responsible for receiving the image light reflected by the DMD chip 209 and refracted by the internal total reflection prism 208, and amplifying it to form a projection image. The specific design and parameter selection of the projection lens 300 will be adjusted according to the actual application scenario and projection requirements.

[0142] Since the laser illumination module has a zoom function and is compatible with DMDs of different sizes, the optical projection system can also adapt to projection chips of different sizes and types, thereby improving the versatility and flexibility of the system.

[0143] According to another embodiment of the present application, a smart head-mounted device is provided, wherein the smart head-mounted device includes a housing and the optical projection system as described above.

[0144] The specific implementation of the intelligent head-mounted device of the embodiment of the present application can refer to the various embodiments of the above-mentioned laser illumination module, and therefore at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0145] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0146] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A laser lighting module, characterized in that: include: A first lens group, comprising at least one of a first lens (201) and a second lens (202), and a diffusion plate (203); A fly-eye lens (204), located on the light-emitting side of the first lens group; A second lens group includes a third lens (205) and a fourth lens (207); A reflector (206), located on the optical path between the third lens (205) and the fourth lens (207), and used to change the direction of the optical path; An internal total reflection prism (208), located on the light exit side of the fourth lens (207); A DMD chip (209) is arranged adjacent to the total internal reflection prism (208); The fourth lens (207) is movable along its optical axis to change the distance between it, the third lens (205) and the total internal reflection prism (208), thereby achieving zooming; The DMD chip (209) receives the zoomed illumination light, so that the laser illumination module can match DMD chips (209) of different sizes.

2. The laser lighting module according to claim 1, characterized in that: The laser illumination module satisfies the following: 1.2≤|f1 / f2|≤1.5; wherein f1 and f2 are respectively the focal lengths of the laser illumination module corresponding to when the DMD chip (209) is 0.39 inches and 0.47 inches.

3. The laser lighting module according to claim 2, characterized in that: When the first lens group includes a first lens (201) and a second lens (202), the diffusion sheet (203) is located between the first lens (201) and the second lens (202).

4. The laser lighting module according to claim 3, characterized in that: The first lens (201), the second lens (202), the third lens (205) and the fourth lens (207) are glass spherical lenses.

5. The laser lighting module according to claim 4, characterized in that: When the DMD chip (209) is 0.39 inches, the F number of the laser illumination module is F1, and when the DMD chip (209) is 0.47 inches, the F number of the laser illumination module is F2, and F1<F2.

6. The laser lighting module according to claim 4, characterized in that: When the DMD chip (209) is 0.39 inches, the optical effective aperture of the fourth lens (207) is D1; ​​when the DMD chip (209) is 0.47 inches, the optical effective aperture of the fourth lens (207) is D2, and D1 = D2.

7. The laser lighting module according to claim 4, characterized in that: The optical power of the first lens (201), the second lens (202), the third lens (205) and the fourth lens (207) are all positive.

8. The laser lighting module according to claim 7, characterized in that: The first lens (201) is a convex-concave lens, the second lens (202) is a concave-convex lens, and the third lens (205) and the fourth lens (207) are biconvex lenses.

9. The lighting module according to claim 4, characterized in that: The compound eye lens (204) is a double-sided compound eye, the incident light angle thereof is ≤10°, and the thickness thereof is ≤5 mm.

10. The laser lighting module according to claim 4, characterized in that: The first lens (201), the second lens (202) and the third lens (205) are arranged along a first optical axis, the fourth lens (207) is arranged along a second optical axis, and the first optical axis and the second optical axis form an angle; The reflector (206) is arranged at an angle and is used to project the light emitted by the third lens (205) to the fourth lens (207).

11. The laser lighting module according to claim 4, characterized in that: The second lens group also includes a fifth lens, which is located between the third lens (205) and the fourth lens (207).

12. The laser lighting module according to any one of claims 1 to 11, characterized in that: The lighting module also includes a laser light source (100) located on the light incident side of the first lens group.

13. An optical projection system, characterized in that: include: The laser lighting module according to any one of claims 1 to 12; and A projection lens (300), wherein the projection lens (300) is located on the light-emitting side of the total internal reflection prism (208).

14. A smart head-mounted device, characterized in that: include: shell; and The optical projection system of claim 13.

Images