Projection module and lighting system

Abstract

The present invention provides a projection module and an illumination system thereof, wherein the illumination system includes a light source, a focusing lens group, and a light homogenizing rod, wherein light emitted by the light source is converged by the focusing lens group to form a focusing light path, wherein the light enters the light homogenizing rod along the focusing light path and is reflected by the light homogenizing rod to form at least one reflected light path, wherein the focusing lens group includes a first lens and a second lens, wherein the first lens is located at the front end of the light incident direction of the second lens, wherein the second lens is a cylindrical lens having an optical focal length along a V direction, so that the divergence angle of the light along the H direction is greater than that along the V direction, thereby increasing the number of reflections of the light along the H direction.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a projection module and an illumination system thereof. Background Art

[0002] The emergence of projection display technology based on micro-display chips has enabled projection equipment to develop in the direction of miniaturization and high resolution. The projection module combines optics and mature semiconductor technology and is a cost-effective way to achieve large-size, high-resolution display.

[0003] Figure 1 and Figure 2 A prior art projection module is disclosed, comprising a light source, a light homogenizer, a relay lens, a PBS prism, an LCOS chip, and a projection lens. The light source typically includes a focusing lens to control the angle of the light. The light is homogenized by the light homogenizer, forming a uniform illumination at the exit end of the light homogenizer. The relay lens forms an image of the uniform illumination onto the LCOS chip, which is then modulated into an image by the LCOS and projected through the projection lens.

[0004] The light emitted by the light source is reflected multiple times in the homogenizing rod, and each reflection forms a virtual light source image. Multiple reflections form a two-dimensional virtual light source matrix, making the light more uniform. However, this is limited to uniform illumination near the exit end of the homogenizing rod. Once it is away from the exit end face of the homogenizing rod, it will become uneven again. Generally speaking, the light will become significantly uneven 0.5mm away from the exit end face of the homogenizing rod. The use of a reflective display chip such as LCOS requires a PBS prism to be set in the front section of the display chip, which greatly increases the distance from the exit end face of the homogenizing rod to the display chip. Therefore, a relay lens is generally provided in the existing solution to image the uniform illumination of the exit end face of the homogenizing rod to the LCOS chip. The addition of a relay lens not only increases the complexity and volume of the system, but also makes it difficult to assemble a projection system with more components, and the probability of assembly errors is higher. The importance of the consistency of the optical axes of the components to the performance of the projection system is self-evident.

[0005] Figure 3 This is a Chinese invention patent application with publication number CN101614946A, which discloses a projection system comprising a light source (1), a light homogenizing rod (2), a relay imaging system (3), a display chip (5), a PBS prism (4), and a projection lens (6). The light emitted by the light source is homogenized by the light homogenizing rod, then shaped by the relay imaging system before being incident on the display chip, modulated into an image by the display chip, and then projected out through the projection lens. The figure shows a reflective display chip LCOS, so a PBS prism is required. In this solution, the relay imaging system has a magnification of 3-10 times and has a beam shaping capability.

[0006] In the technical solution of this application, an optical device is used to shape the light beam emitted by the light source to obtain parallel or nearly parallel light, and the light is then homogenized by a homogenizer. Because the angle of light incident on the homogenizer is small, the length of the homogenizer is required to achieve a uniform exit end face, resulting in a large structural dimension. The light beam emitted by the light source directly enters the homogenizer. Due to the large angle of the incident beam, the beam undergoes multiple reflections and mixing within the shorter homogenizer, forming a uniformly distributed illumination at the exit end face of the homogenizer. Because the magnification of the relay imaging system is 3-10, the optical shaping step is completed in the relay imaging system. The uniform illumination of the exit end face of the homogenizer is amplified by the relay imaging system and imaged on the microdisplay chip, thereby meeting the light incidence angle requirements of the microdisplay chip.

[0007] Even if the light source is directly attached to the incident end face of the homogenizer rod, so that the incident light at a larger angle is reflected multiple times in the homogenizer rod, thereby shortening the structural size of the homogenizer rod, the existence of the relay imaging system requires the uniform illumination of the output end face of the homogenizer rod to be imaged onto the display chip. The existence of the relay imaging system makes the projection system structure complicated, which is not conducive to its miniaturization. In particular, for micro-projection systems used in wearable devices, the size seriously affects the experience of wearable devices.

[0008] In addition, since the relay imaging system needs to amplify the uniform illumination of the output end face of the homogenizing rod to be sufficient to cover the display chip, as stated in the patent, the relay imaging system has a magnification capability of 3-10 times. A certain magnification capability requires the lens to have a shorter focal length. Generally speaking, the greater the curvature of the lens surface, the shorter the focal length. Generally speaking, the lens also has a greater thickness, or multiple lenses are used to achieve this as in the patent. This results in a larger volume of the relay imaging system, which is not conducive to the application of the lighting system in a micro projector.

[0009] In addition, in the Chinese invention patent with publication number CN101943845A, another light homogenizing device, an optical integrator, is disclosed, which usually includes a front collimator, two microlens arrays, and a rear collimator. The optical integrator is also an optical device that uniformizes the distribution of light radiation. The optical integrator divides the light radiation distribution irradiated on the entrance pupil through an array lens and then superimposes it on the same position of the rear collimator. The uniformity of the light radiation distribution on each array element lens is definitely better than the light radiation distribution of the entire entrance pupil. Therefore, the magnified images are superimposed on each other to obtain a uniform radiation distribution. However, the incident light using the optical integrator must be collimated, that is, a front collimator needs to be set after the light source. The presence of the rear collimator makes the entire lighting system larger. Usually, three RGB light sources are also required in the color projection module, and an additional light combining element needs to be configured, which further increases the volume of the lighting system.

[0010] In existing solutions, whether using a homogenizer rod or an array lens integrator, a collimation or relay imaging system is required, which makes the system more complicated. Assembling all the components together in the projection module requires many steps and the assembly is complicated, making it difficult to achieve high optical axis consistency.

[0011] Therefore, the projection modules of the prior art, especially the projection modules used in micro-projection systems, still have at least one of the following defects: first, the overall size and volume of the projection module are large, which affects the size of the overall product and cannot meet the demand; second, the assembly relationship between the components in the lighting system of the projection module needs to be precisely controlled. As the number of components increases, the assembly difficulty increases, the error increases, and it is difficult to achieve consistency between the front and rear optical axes; third, for different sizes of projection surfaces, the light divergence angles of the projection modules of the prior art in the horizontal and vertical directions are small, resulting in poor uniform lighting effect in a certain direction, incorrect lighting area or uneven illumination on the left and right; fourth, the focusing ability of the lighting system of the projection module of the prior art is weak, resulting in waste of light energy and low light efficiency. Summary of the Invention

[0012] A major advantage of the present invention is that it provides a projection module and an illumination system thereof, wherein the illumination system of the projection module has a relatively small overall size, which is conducive to miniaturization of the projection module.

[0013] Another advantage of the present invention is that it provides a projection module and its lighting system, wherein the projection module further includes a display chip and a spectroscopic component, and the lighting system includes a light source, a focusing lens group and a light homogenizing rod, wherein the spectroscopic component and part of the light homogenizing rod form a PBS prism, so that the distance between the output end of the light homogenizing rod and the display chip is short, thereby eliminating the relay imaging system and reducing the volume of the projection module.

[0014] Another advantage of the present invention is that it provides a projection module and its lighting system, wherein the lighting system eliminates lens components, reduces system complexity, improves assembly convenience, thereby reducing the overall assembly error of the projection module and improving optical axis consistency.

[0015] Another advantage of the present invention is that it provides a projection module and its lighting system, wherein the focusing lens group is composed of a spherical mirror and a cylindrical mirror, which solves the problem in the traditional solution that the two spherical mirrors bring about small light divergence angles in the V direction and H direction, resulting in poor light uniformity in the H direction.

[0016] Another advantage of the present invention is to provide a projection module and its lighting system, wherein the central light of the light-homogenizing rod and the light-splitting component of the lighting system is vertically incident on the chip center of the display chip, which is beneficial to improving the uniformity of the lighting of the lighting system.

[0017] Another advantage of the present invention is that it provides a projection module and its lighting system, wherein the focusing lens group includes a first lens and a second lens, wherein the first lens is a cylindrical lens, which is beneficial to increasing the light divergence angle of the light homogenizer in the H direction, so as to increase the number of reflections of the light in the H direction. Each reflection will form a virtual light source image to obtain a two-dimensional virtual light source matrix. The more virtual light sources there are, the more uniform the final emitted light will be.

[0018] Another advantage of the present invention is that it provides a projection module and an illumination system thereof, wherein the focusing lens group has a better focusing effect, greatly reduces light energy waste, and improves the light efficiency by more than 3 times.

[0019] Another advantage of the present invention is to provide a projection module and a lighting system thereof, wherein the projection module is small in size, which is conducive to miniaturization of the device.

[0020] According to one aspect of the present invention, a lighting system of the present invention that can achieve the aforementioned objects and other objects and advantages includes:

[0021] a light source;

[0022] a condensing lens group, wherein the light emitted by the light source is converged by the condensing lens group to form a condensing light path; and

[0023] A light homogenizing rod, wherein the light enters the light homogenizing rod along the focusing light path and is reflected by the light homogenizing rod to form at least one reflected light path, wherein the light homogenizing rod includes an incident end, an exit end, and a light homogenizing body located between the incident end and the exit end, and the light is reflected multiple times from the incident end, the light homogenizing body, and the exit end along a light homogenizing optical axis of the light homogenizing rod to form the reflected light path, wherein the incident end has an incident end face, and the incident end face of the incident end is an oblique cut surface formed at the end of the incident end.

[0024] According to an embodiment of the present invention, the light homogenizing rod is a rectangular glass rod that is wide in the H direction and narrow in the V direction.

[0025] According to one embodiment of the present invention, the focusing lens group includes a first lens and a second lens, the first lens is located at the front end of the light incident direction of the second lens, and the second lens is a cylindrical lens with optical focal length along the V direction, so that the divergence angle of the light along the H direction is greater than that along the V direction, thereby increasing the number of reflections of the light along the H direction.

[0026] According to an embodiment of the present invention, the first lens is a spherical lens.

[0027] According to an embodiment of the present invention, an angle of 45° is formed between the incident end surface and the lower end surface of the incident end.

[0028] According to one embodiment of the present invention, the light source has a light-emitting surface, the light-emitting surface of the light source is parallel to the incident end surface of the incident end, wherein the focusing lens group has a focusing axis, and the focusing axis of the focusing lens group is perpendicular to the incident end surface of the light homogenizing rod.

[0029] According to one embodiment of the present invention, the output end of the light homogenizing rod further has an output end face, wherein the output end face of the output end is an oblique cut surface formed at the end of the output end, and the output end face of the output end is parallel to the incident end face of the incident end.

[0030] According to one embodiment of the present invention, the output end of the light homogenizing rod further has an output end face, wherein the output end face of the output end is an oblique cut surface formed at the end of the output end, and the output end face of the output end is perpendicular to the incident end face of the incident end.

[0031] According to another aspect of the present invention, the present invention further provides a projection module, comprising:

[0032] An illumination system, wherein the illumination system comprises a light source, a condensing lens group and a light homogenizing rod, wherein the condensing lens group is arranged between the light source and the light homogenizing rod;

[0033] a display chip; and

[0034] A light-splitting component, wherein the light-splitting rod further includes an incident end, an exit end, and a light-splitting body located between the incident end and the exit end, the display chip and the light-splitting component are arranged in the light exit direction of the exit end of the light-splitting rod, wherein the light-splitting rod has a light-splitting optical axis, the light-splitting component is glued to the exit end, and the light with image information reflected by the display chip forms a projection light path through the light-splitting component, wherein the projection light path extends obliquely in the direction opposite to the light-splitting optical axis of the light-splitting rod to reduce the length of the projection module along the light-splitting optical axis of the light-splitting rod.

[0035] According to one embodiment of the present invention, the output end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located on an upper end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends upward at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod.

[0036] According to one embodiment of the present invention, the output end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located at a lower end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends downward at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod.

[0037] According to an embodiment of the present invention, the device further comprises a projection lens, wherein the projection lens is arranged at the light emitting end of the light splitting component along the projection light path.

[0038] According to one embodiment of the present invention, the spectroscopic component includes a prism and a spectroscopic film, wherein the prism has a prism incident end face and a prism exit end face, and the spectroscopic film is integrally formed on the prism incident end face of the prism, and the imaging light is incident on the prism through the prism incident end face of the prism, and is emitted from the prism exit end face of the prism to the projection lens.

[0039] According to one embodiment of the present invention, the incident end of the light homogenizing rod has an incident end face, wherein the incident end face is the beveled surface formed at the incident end, and the light source and the focusing lens group are located obliquely above the light homogenizing rod to reduce the length of the projection module along the light homogenizing optical axis direction of the light homogenizing rod.

[0040] According to an embodiment of the present invention, the incident end face of the incident end forms an angle of 45° with the lower end face, and the focusing lens group has a focusing axis, which is perpendicular to the incident end face of the light homogenizing rod.

[0041] According to an embodiment of the present invention, the focusing lens group includes a first lens and a second lens, wherein the first lens is located at the front end of the light incident direction of the second lens, and the first lens and the second lens are spherical lenses.

[0042] According to one embodiment of the present invention, the focusing lens group includes a first lens and a second lens, wherein the first lens is located at the front end of the light incident direction of the second lens, wherein the first lens is a spherical lens, the second lens is a cylindrical lens, and the second lens has a V-direction optical focal length.

[0043] According to an embodiment of the present invention, the light homogenizing rod is a rectangular glass rod that is wide in the H direction and narrow in the V direction.

[0044] According to another aspect of the present invention, the present invention further provides a projection module, comprising:

[0045] A lighting system, wherein the lighting system comprises:

[0046] A lighting system as described in any one of the above;

[0047] A light splitting component and a display chip, wherein the light splitting component is arranged at the output end of the light homogenizing rod, and the light splitting component selectively transmits or reflects part of the light to the display chip, and the display chip reflects the light with image information.

[0048] According to an embodiment of the present invention, the first lens is a spherical lens.

[0049] According to an embodiment of the present invention, the light homogenizing rod is a rectangular glass rod that is wide in the H direction and narrow in the V direction.

[0050] According to one embodiment of the present invention, the focusing lens group includes a first lens and a second lens, the first lens is located at the front end of the light incident direction of the second lens, and the second lens is a cylindrical lens with optical focal length along the V direction, so that the divergence angle of the light along the H direction is greater than that along the V direction, thereby increasing the number of reflections of the light along the H direction.

[0051] According to an embodiment of the present invention, an angle of 45° is formed between the incident end surface and the lower end surface of the incident end.

[0052] According to one embodiment of the present invention, the light source has a light-emitting surface, the light-emitting surface of the light source is parallel to the incident end surface of the incident end, wherein the focusing lens group has a focusing axis, and the focusing axis of the focusing lens group is perpendicular to the incident end surface of the light homogenizing rod.

[0053] According to one embodiment of the present invention, the output end of the light homogenizing rod further has an output end face, wherein the output end face of the output end is an oblique cut surface formed at the end of the output end, and the output end face of the output end is parallel to the incident end face of the incident end.

[0054] According to one embodiment of the present invention, the output end of the light homogenizing rod further has an output end face, wherein the output end face of the output end is an oblique cut surface formed at the end of the output end, and the output end face of the output end is perpendicular to the incident end face of the incident end.

[0055] According to one embodiment of the present invention, the light splitting component is glued to the output end, and the light carrying image information reflected by the display chip forms a projection light path through the light splitting component, wherein the projection light path extends obliquely in the direction opposite to the light homogenizing axis of the light homogenizing rod to reduce the length of the projection module along the light homogenizing axis of the light homogenizing rod.

[0056] According to one embodiment of the present invention, the output end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located on an upper end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends upward at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod.

[0057] According to one embodiment of the present invention, the output end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located at a lower end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends downward at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod.

[0058] According to an embodiment of the present invention, the device further comprises a projection lens, wherein the projection lens is arranged at the light emitting end of the light splitting component along the projection light path.

[0059] According to one embodiment of the present invention, the spectroscopic component includes a prism and a spectroscopic film, wherein the prism has a prism incident end face and a prism exit end face, and the spectroscopic film is integrally formed on the prism incident end face of the prism, and the imaging light is incident on the prism through the prism incident end face of the prism, and is emitted from the prism exit end face of the prism to the projection lens.

[0060] Further objects and advantages of the present invention will be fully apparent from an understanding of the following description and accompanying drawings.

[0061] These and other objects, features and advantages of the present invention will be more fully understood from the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a structural diagram of a projection module in the prior art.

[0063] Figure 2 It is a schematic diagram of the optical path of the projection module in the prior art.

[0064] Figure 3 FIG. 1 is a schematic diagram of a compact optical engine system based on a microdisplay chip in the prior art.

[0065] Figure 4 FIG. 1 is a schematic diagram of the three-dimensional structure of a projection module according to a first preferred embodiment of the present invention.

[0066] Figure 5 2 is a schematic diagram of the planar structure of the projection module according to the first preferred embodiment of the present invention.

[0067] Figure 62 is a schematic structural diagram of the projection module according to the first preferred embodiment of the present invention.

[0068] Figure 7 2 is a schematic diagram of an optical path structure of the projection module along the V direction according to the first preferred embodiment of the present invention.

[0069] Figure 8A 2 is a schematic diagram of an optical path structure of the projection module along the H direction according to the first preferred embodiment of the present invention.

[0070] Figure 8B FIG. 2 is a schematic diagram of another optical path structure of the projection module along the H direction according to the first preferred embodiment of the present invention.

[0071] Figure 9 3 is a structural diagram of another optional implementation of the projection module according to the first preferred embodiment of the present invention.

[0072] Figure 10 3 is a structural diagram of another optional implementation of the projection module according to the first preferred embodiment of the present invention. DETAILED DESCRIPTION

[0073] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are for illustrative purposes only, and those skilled in the art will readily appreciate other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0074] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0075] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0076] Referring to the accompanying drawings of the present invention Figures 4 to 8BThe following description illustrates a projection module according to a first preferred embodiment of the present invention. The projection module includes an illumination system 10, a display chip 20 positioned in the light-emitting direction of the illumination system, and a beam splitter 30. Illumination light emitted by the illumination system 10 is selectively reflected by the beam splitter 30 toward the display chip 20. The beam is then modulated by the display chip 20 to form an image-bearing beam, which is then projected outward through the beam splitter. The lighting system 10 includes a light source 11, a focusing lens group 12 and a homogenizing rod 13, wherein the light emitted by the light source 11 is projected onto the focusing lens group 12 and converged by the focusing lens group 12 to form a focusing light path 120; the light enters the homogenizing rod 13 along the focusing light path 120, is reflected by the homogenizing rod 13 and forms at least one reflected light path 130 within the homogenizing rod 13; the light is emitted along the reflected light path 130 to the display chip 20 or the light-splitting component 30, and forms an illumination spot on the surface of the display chip 20.

[0077] like Figure 4 As shown, the projection module further includes at least one projection lens 40, wherein the projection lens 40 is arranged on the light-emitting side of the light-splitting component 30, and the image light emitted by the display chip 20 is projected outward through the light-splitting component 30 and the projection lens 40 to form a projection pattern.

[0078] Specifically, the light source 11 is used for illumination, and emits illuminating light. Preferably, in this preferred embodiment of the present invention, the light source 11 is implemented as an LED, wherein the light source emits light at an angle of approximately 120°. It should be understood that the type of light source and the light angle are provided herein for illustrative purposes only, and are not intended to be limiting.

[0079] The condenser lens assembly 12 of the illumination system 10 has a condenser optical axis O1, and the condenser lens assembly 12 converges the light emitted by the light source 11 along the condenser optical axis O1 to form the condenser optical path 120. The condenser lens assembly 12 includes a first lens 121 and a second lens 122, wherein the first lens 121 is located at the front end of the light incident direction of the second lens 122. That is, the light emitted by the light source 11 is converged by the first lens 121 to the second lens 122, and then converged by the second lens 122 to form the condenser optical path 120. Preferably, in this preferred embodiment of the present invention, the central light of the condenser lens assembly 12 is emitted from the condenser lens assembly 12 along the condenser optical axis O1 to the light homogenizing rod 13.

[0080] like Figure 8A and Figure 8BTwo different embodiments of the condenser lens assembly 12 of the present invention are shown. Figure 8A As described above, the first lens 121a and the second lens 122a of the condenser lens group 12 are spherical mirrors, so that the condenser lens group 12 has optical focal lengths in the V direction (horizontal direction) and the H direction (vertical direction), that is, the condenser lens group 12 has the same convergence and divergence effect in the V direction and the H direction. Figure 8B As shown, the first lens 121b of the condenser lens assembly 12 is a spherical lens, and the second lens 122b of the condenser lens assembly 12 is a cylindrical lens. Because the cylindrical lens has optical power in the V direction and no optical power in the H direction, the divergence angle of the light in the H direction is larger than that in the V direction, thereby increasing the number of reflections of the light in the H direction. It can be understood that each reflection forms a virtual light source image to obtain a two-dimensional virtual light source matrix. A greater number of virtual light sources results in a more uniform final emitted light.

[0081] Correspondingly, if two spherical mirrors are used as the focusing lens group, the light divergence angles in the V and H directions are consistent. Since the smaller the light divergence angle in the V direction, the better, and the smaller the divergence angle in the H direction, the fewer times the light is reflected on the two side walls of the homogenizer rod, and the poor homogenization effect in the H direction.

[0082] The display chip 20 of the projection module has a chip reflection surface 201, wherein the chip reflection surface 201 faces the light-homogenizing rod 13 of the illumination system 10, and the image light is reflected by the chip reflection surface 201 to the light-splitting component 30. It is worth mentioning that in this preferred embodiment of the present invention, the chip reflection surface 201 of the display chip 20 is a rectangular surface. Preferably, the chip reflection surface 201 of the display chip 20 is a 16:9 rectangular surface. It will be understood by those skilled in the art that the specific shape and proportion of the chip reflection surface 201 of the display chip 20 are merely exemplary and not restrictive. In other optional embodiments of the present invention, the shape and size of the display chip 20 can be adjusted as needed.

[0083] Preferably, the light homogenizing rod 13 is a square rod that is wide in the H direction and narrow in the V direction. This allows the uniform illumination spot modulated by the light homogenizing rod 13 to approximate the shape of the display chip, reducing light energy waste. Accordingly, in this preferred embodiment of the present invention, the first lens 121 of the condenser lens assembly 12 is a spherical lens, and the second lens 122 is a cylindrical lens. Because the cylindrical lens has optical power in the V direction but no optical power in the H direction, the light divergence angle in the H direction is larger than that in the V direction, thereby increasing the number of reflections in the H direction. Each reflection forms a virtual light source image, resulting in a two-dimensional virtual light source matrix. A greater number of virtual light sources results in a more uniform final output light.

[0084] It is worth mentioning that in this preferred embodiment of the present invention, the light collecting ability of the display chip 20 is generally about 60°. The focusing lens group 12 of the present application has a better focusing effect than the prior art. The focusing lens group 12 can collect light to 50°~70°, greatly reducing the waste of light energy and improving the light efficiency by more than 3 times.

[0085] like Figures 4 to 8B As shown, the light homogenizing rod 13 of the illumination system 10 is a rectangular glass rod. Preferably, in this preferred embodiment of the present invention, the refractive index of the material of the light homogenizing rod 13 is in the range of 1.5 to 1.7. The light homogenizing rod 13 includes an incident end 131, an exit end 132, and a light homogenizing body 133 located between the incident end 131 and the exit end 132. Light is incident on the incident end 131 of the light homogenizing rod 13 along the focusing optical path 120. The light is reflected multiple times along a light homogenizing optical axis O2 of the light homogenizing rod 13 through the incident end 131, the light homogenizing body 133, and the exit end 132 to form the reflected optical path 130, and then emitted through the exit end 132 to the display chip 20.

[0086] It's worth noting that each reflection of light forms a virtual light source image, generating a two-dimensional virtual light source matrix based on the chip reflective surface 201 of the display chip 20. A greater number of virtual light sources results in a more uniformly emitted light. Each reflection of light passing through the homogenizing rod 13 forms a reflected light path 130. Therefore, the number of times light is reflected within the homogenizing rod 13 directly determines the illumination of the lighting system 10.

[0087] The light homogenizing rod 13 further has an upper end surface 134 and a lower end surface 135 directly opposite to the upper end surface 134, wherein the upper end surface 134 and the lower end surface 135 of the light homogenizing rod 13 are facing reflective surfaces, and part of the light is reflected between the upper end surface 134 and the lower end surface 135 of the light homogenizing rod 13 to form a plurality of V-direction reflective light paths 130a along the V direction. The light homogenizing rod 13 further has a left end surface 136 and a right end surface 137 directly opposite to the left end surface 136, wherein the left end surface 136 and the right end surface 137 of the light homogenizing rod 13 are facing reflective surfaces, and part of the light is reflected between the left end surface 136 and the right end surface 137 of the light homogenizing rod 13 to form a plurality of H-direction reflective light paths 130b along the H direction. It can be understood that the V-direction reflective light path 130 a and the H-direction reflective light path 130 b constitute at least part of the reflective light path 130 .

[0088] The incident end 131 of the light homogenizing rod 13 is further provided with an incident end surface 1310. The light focused by the condensing lens group 12 is incident on the light homogenizing rod 13 through the incident end surface 1310 of the incident end 131. The incident end surface 1310 of the incident end 131 is an oblique surface formed at the end of the incident end 131. After the light focused by the condensing lens group 12 is incident on the incident end surface 1310 of the incident end 131, it is refracted onto each end surface (the upper end surface 134, the lower end surface 135, the left end surface 136, or the right end surface 137) of the light homogenizing rod 13 and reflected between the end surfaces to form the reflected light path 130.

[0089] It is worth mentioning that the focusing optical axis O1 of the focusing lens group 12 intersects or intersects with the light homogenizing optical axis O2 of the light homogenizing rod 13. In other words, in this preferred embodiment of the present invention, the light converged by the focusing lens group 12 is incident obliquely downward along the focusing optical path 120 onto the incident end surface 1310 of the light homogenizing rod 13. That is, the light source 11 and the focusing lens group 12 are located obliquely above the light homogenizing rod 13, which helps to reduce the length of the projection module along the light homogenizing optical axis O2, thereby facilitating the miniaturization of the projection module.

[0090] Preferably, in this preferred embodiment of the present invention, the incident end surface 1310 of the incident end 131 forms an angle of 45° with the lower end surface 135. More preferably, the focusing optical axis O1 of the condensing lens assembly 12 is perpendicular to the incident end surface 1310 of the light homogenizing rod 13. That is, the central light beam converged by the condensing lens assembly 12 is perpendicularly incident on the incident end surface 1310 of the light homogenizing rod 13. This increases the number of reflections of the light beam within the light homogenizing rod 13, i.e., increases the number of reflection paths 130, which is beneficial to the light homogenization effect of the light homogenizing rod 13. The light source 11 of the lighting system 10 has a light-emitting surface 110, wherein the light source 11 emits illumination light outward from the light-emitting surface 110, the light-emitting surface 110 of the light source 11 is parallel to the incident end surface 1310 of the incident end 131 of the light-homogenizing rod 13, and the focusing optical axis O1 of the focusing lens group 12 is perpendicular to the incident end surface 1310 of the light-homogenizing rod 13, so that the central light can be incident perpendicular to the incident end surface, thereby maximizing the number of reflections of the light in the V direction in the light-homogenizing rod, thereby improving the light homogenization effect of the lighting system 10 in the V direction.

[0091] like Figures 4 to 6As shown, the output end 132 of the light homogenizing rod 13 has an output end surface 1320, wherein the output end surface 1320 is formed at the end of the output end 132. The chip reflection surface 201 of the display chip 20 is directly opposite the output end surface 132 of the light homogenizing rod 13. Reflected light is emitted from the output end surface 1320 of the output end 132 of the light homogenizing rod 13 to the display chip 20. Preferably, the chip reflection surface 201 of the display chip 20 is parallel to the output end surface 132 of the light homogenizing rod 13. Preferably, the output end surface 1320 of the light homogenizing rod 13 is a chamfered surface formed at the output end 132, and is parallel to the incident end surface 1310 of the incident end 131.

[0092] The light-splitting component 30 is disposed at the output end 132 of the light-homogenizing rod 13, and the light-splitting component 30 has a selective effect on light, and can selectively transmit and / or reflect part of the light. The output end 132 of the light-homogenizing rod 13 is further provided with a light-transmitting area 1321, wherein the reflected light can transmit the light-transmitting area 1321 of the output end 132, and the light-splitting component 30 is disposed at the light-transmitting area 1321 of the output end 132. Preferably, in this preferred embodiment of the present invention, the light-splitting component 30 is glued to the light-transmitting area 1321 of the output end 132 of the light-homogenizing rod 13, and the light reflected by the light-homogenizing rod 13 reaches the light-splitting component 30 through the light-transmitting area 1321 of the output end 132, and the light-splitting component 30 selectively reflects and / or transmits part of the light. More preferably, the light-transmitting area 1321 of the emission end 132 of the light-homogenizing rod 13 is located on the upper end surface 134 of the light-homogenizing rod 13 .

[0093] The light-splitting component 30 includes a prism 31 and a prismatic film 32, wherein the prismatic film 32 is disposed on the prism 31 and selectively reflects and / or transmits a portion of the light. Preferably, in this preferred embodiment of the present invention, the prismatic film 32 is a PBS film that selectively projects P light and reflects S light.

[0094] More preferably, the prism 31 is a right-angle prism having a prism incident end face 311 and a prism exit end face 312, wherein the beam splitter film 32 is integrally formed on the prism incident end face 311 of the prism 31. The imaging light emitted by the display chip 20 enters the prism 31 through the prism incident end face 311 of the prism 31 and exits from the prism exit end face 312 of the prism 31 to the projection lens 40. It is worth mentioning that the prism incident end face 311 of the prism 31 is the inclined surface of the right-angle prism, that is, a polarizing beam splitter film (PBS film) is coated on the inclined surface of the prism 31 to form the beam splitter component 30.

[0095] Light reflected by the light homogenizing rod 13 passes through the light-transmitting region 1321 of the output end 132 and forms a splitting optical path 320 via the beam splitter film 32. P light is transmitted, while S light is reflected by the beam splitter film 32 to the display chip 20 at the end of the light homogenizing rod 13. After modulation by the display chip 20, the S light is converted into P light, which is then reflected by the display chip 20 to form imaging light containing image information and to the beam splitter film 32. The beam splitter film 32 transmits the imaging light containing image information to the projection lens 40, which then projects the imaging light outward to form a projected image.

[0096] Taking the central light as an example, when the central light reaches the upper end surface 134 of the light-dividing rod 13 from the output end 132 of the light-dividing rod 13, it forms an angle of 45° with the light-transmitting area 1321. After the action of the spectroscopic film 32, the P light is transmitted, and the S light is reflected and vertically incident on the display chip 20. After modulation by the display chip 20, the S light becomes P light, which is reflected by the micro-mirror in the display chip 20 to the spectroscopic film 32. The P light is transmitted into the projection lens to form the final image.

[0097] The light beam carrying imaging information, modulated by the display chip 20, passes through the output end 132 of the light-splitting rod 13 and the prism 31 and the beam-splitting film 32 of the beam-splitting component 30 to form a projection light path 321. The light beam carrying imaging information travels along the projection light path 321 to the projection lens 40. It is worth noting that, in this preferred embodiment of the present invention, the projection light path 321 formed by transmission through the beam-splitting film 32 extends upwardly and obliquely in a direction opposite to the light-splitting optical axis O2, meaning that the projection lens 40 is located obliquely above the beam-splitting component 30 along the projection light path 321. Therefore, in this preferred embodiment of the present invention, the specific light path design, namely, adjusting the position of the projection lens 40 in the direction of the projection light path 321, facilitates reducing the length of the projection module along the light-splitting optical axis O2 and facilitates miniaturization of the projection module.

[0098] In the prior art, incident S-polarized light is reflected by the PBS prism and then illuminates the display chip 20. When the applied voltage to a pixel in the liquid crystal layer is 0, the input S-polarized light passes through the liquid crystal layer without undergoing any polarization change. It reflects back from the bottom and outputs S-polarized light. After being reflected by the PBS prism spectrometer, the S-polarized light returns along its original path and cannot enter the transmitted light path. The light output is zero, and the pixel appears "dark." When an external voltage is applied to the pixel, the input S-polarized light passes through the liquid crystal layer, undergoing any polarization change. It reflects back from the bottom and outputs P-polarized light. This light directly passes through the PBS prism spectrometer and enters the transmitted light path. The pixel appears "bright," forming an image on the screen. The PBS prism spectrometer is composed of two prisms glued together, one of which is coated with a PBS film. When natural light strikes the PBS film, the P-light is transmitted while the S-light is reflected.

[0099] It is worth mentioning that in this preferred embodiment of the present invention, the light-splitting component 30 is glued to the upper end surface 134 of the light-splitting rod 13, and the light-splitting component 30 is located at the output end 132. The light-splitting component 30 and at least part of the output end 132 of the light-splitting rod 13 form a PBS prism. In other words, part of the structure of the PBS prism is integrally formed at the output end 132 of the light-splitting rod 13. In this way, the distance between the output end of the light-splitting rod and the display chip is reduced, so that the uniform illumination of the output end surface of the light-splitting rod can still maintain a high degree of uniformity when projected onto the display chip. At the same time, this solution eliminates the relay lens and cancels the assembly process between the light-splitting rod, relay lens and PBS prism, thereby improving the production efficiency, reducing the assembly error, and thus improving the optical axis consistency of the projection system.

[0100] In other words, in this preferred embodiment of the present invention, the design of the light-distributing rod 13 and the light-splitting component 30 ensures that the central light beam is incident perpendicularly to the center of the display chip 20, thereby reducing the possibility of misaligned illumination or uneven left-right illumination. Furthermore, when the light-distributing rod 13 is the same length, the focusing lens assembly 12 is positioned obliquely above the light-distributing rod 13, and the light-splitting component 30 and the projection lens 40 are positioned above the light-distributing rod 13, thereby reducing its longitudinal length to a certain extent. This makes the projection module provided by this application smaller in size, facilitating device miniaturization.

[0101] Referring to the accompanying drawings of the present invention Figure 9As shown, a projection module according to the first preferred embodiment of the present invention is explained in the following description. The projection module includes an illumination system 10, a display chip 20 arranged in the light emitting direction of the illumination system, and a spectroscopic component 30. The illumination light emitted by the illumination system 10 is selectively reflected by the spectroscopic component 30 to the display chip 20, and then modulated by the display chip 20 to form a light with an image, which is projected outward through the spectroscopic component to form an image. In this preferred embodiment of the present invention, the structure and function of the illumination system 10, the display chip 20 and the spectroscopic component 30 are basically the same as those of the first preferred embodiment. The difference lies in the position of the display chip 20, so as to better match the overall structural design of the near-eye display device.

[0102] Specifically, the prism 31 of the light-splitting component 30 is located at the upper end of the light-homogenizing rod 13 and further comprises a light-transmitting surface 313, wherein the display chip 20 is directly opposite the light-transmitting surface 313 of the prism 31. The light-transmitting surface 313 of the prism 31 is adjacent to the prism exit end face 312. A portion of the light selectively transmitted by the light-splitting film 32 can pass through the light-transmitting surface 313 of the prism 31. Image light carrying display information reflected by the display chip 20 enters the prism 31 through the light-transmitting surface 313 of the prism 31, where it is then reflected by the light-splitting film 32 to the prism exit end face 312. Unlike the first preferred embodiment described above, the light-splitting film 32 of the light-splitting component 30 selectively reflects and transmits a portion of the light, and the transmitted portion of the light forms a light-splitting optical path 320 within the prism 31.

[0103] Preferably, in this preferred embodiment of the present invention, the chip reflective surface 201 of the display chip 20 is parallel to the light-transmitting surface 313 of the prism 31. It is worth noting that, in this preferred embodiment of the present invention, the projection light path 321 formed by reflection from the beam splitter film 32 extends upwardly and obliquely in a direction opposite to the light-uniform optical axis O2. That is, the projection lens 40 is located obliquely above the beam splitter component 30 along the projection light path 321. Therefore, in this preferred embodiment of the present invention, the specific optical path design, namely, adjusting the position of the projection lens 40 in the direction of the projection light path 321, facilitates reducing the length of the projection module along the light-uniform optical axis O2 and facilitates miniaturization of the projection module.

[0104] Referring to the accompanying drawings of the present invention Figure 10As shown, a projection module according to the above-mentioned first preferred embodiment of the present invention is explained in the following description. The projection module includes an illumination system 10, a display chip 20 arranged in the light emitting direction of the illumination system, a spectroscopic component 30 and at least one projection lens 40. The illumination light emitted by the illumination system 10 is selectively reflected by the spectroscopic component 30 to the display chip 20, and then modulated by the display chip 20 to form a light with an image, which is projected outward through the spectroscopic component to form an image. In this preferred embodiment of the present invention, the structure and function of the display chip 20 and the spectroscopic component 30 are basically the same as those of the above-mentioned first preferred embodiment. The difference lies in the structure of the light-homogenizing rod 13 of the illumination system 10 and the positions of the spectroscopic component 30 and the projection lens 40, so as to better match the overall structural design of the near-eye display device.

[0105] Specifically, the light-emitting end 132 of the light-dispersing rod 13 has a light-transmitting area 1321A, wherein the light-transmitting area 1321A is formed on the lower end surface 135 of the light-dispersing rod 13. The light-splitting component 30 is glued to the light-transmitting area 1321A of the light-emitting end 132 of the light-dispersing rod 13. The projection lens 40 is located at the light-emitting end of the light-splitting component 30, that is, the imaging light is projected onto the projection lens 40 via the prism 31 of the light-splitting component 30.

[0106] The output end 132 of the light homogenizing rod 13 further has an output end surface 1320A, and the display chip 20 is directly opposite the output end surface 1320A. Unlike the first preferred embodiment described above, the output end surface 1320A is an oblique surface. The plane of the oblique surface 1320A is perpendicular to the plane of the incident end surface 1310 of the incident end 131. In other words, the output end surface 1320A is an oblique surface that is inclined from top to bottom, so as to guide the imaging light from the display chip 20 downward to the light splitting component 30.

[0107] It is worth mentioning that in this preferred embodiment of the present invention, the light carrying imaging information, modulated by the display chip 20, passes through the output end 132 of the light-splitting rod 13 and the prism 31 and the beam-splitting film 32 of the beam-splitting component 30 to form a projection light path 321A. The light carrying imaging information travels along this projection light path 321A to the projection lens 40. The projection light path 321A, formed by transmission through the beam-splitting film 32, extends obliquely downward in a direction opposite to the light-splitting optical axis O2, meaning that the projection lens 40 is located obliquely below the beam-splitting component 30 along the projection light path 321A. Therefore, in this preferred embodiment of the present invention, the specific light path design, namely, adjusting the position of the projection lens 40 in the direction of the projection light path 321A, facilitates reducing the length of the projection module along the light-splitting optical axis O2 and facilitates miniaturization of the projection module.

[0108] Those skilled in the art will appreciate that the embodiments of the present invention described above and shown in the accompanying drawings are intended to be illustrative only and are not intended to limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and illustrated in the embodiments. Any variations or modifications may be made to the embodiments of the present invention without departing from the principles described.

Claims

1. A projection module, characterized in that: include: A lighting system, wherein the lighting system comprises: a light source; a condensing lens group, wherein the light emitted by the light source is converged by the condensing lens group to form a condensing light path; and A light homogenizing rod, wherein the light enters the light homogenizing rod along the focusing light path and is reflected by the light homogenizing rod to form at least one reflected light path, wherein the light homogenizing rod includes an incident end, an exit end, and a light homogenizing body located between the incident end and the exit end, and the light is reflected multiple times from the incident end, the light homogenizing body, and the exit end along a light homogenizing optical axis of the light homogenizing rod to form the reflected light path, wherein the incident end has an incident end face, and the incident end face is an oblique cut surface formed at the end of the incident end, wherein the light homogenizing rod is a rectangular parallelepiped glass rod that is wide in the H direction and narrow in the V direction, wherein the light divergence angle along the H direction is greater than that along the V direction, thereby increasing the number of light reflections along the H direction; a light splitting component; and A display chip, wherein the light splitting component is arranged at the output end of the light homogenizing rod, and the light splitting component selectively transmits or reflects part of the light to the display chip, and the display chip reflects the light with image information.

2. The projection module according to claim 1, wherein the focusing lens group includes a first lens and a second lens, the first lens is located at the front end of the light incident direction of the second lens, and the second lens is a cylindrical lens having optical focal length along the V direction. The projection module according to claim 2 , wherein the first lens is a spherical mirror. 4 . The projection module according to claim 3 , wherein the incident end surface and the lower end surface of the incident end form an angle of 45°.

5. The projection module according to claim 4, wherein the light source has a light-emitting surface, the light-emitting surface of the light source is parallel to the incident end surface of the incident end, wherein the focusing lens group has a focusing axis, and the focusing axis of the focusing lens group is perpendicular to the incident end surface of the light homogenizing rod.

6. The projection module according to claim 5, wherein the output end of the light homogenizing rod further has an output end surface, wherein the output end surface of the output end is an oblique surface formed at the end of the output end, and the output end surface of the output end is parallel to the incident end surface of the incident end.

7. The projection module according to claim 5, wherein the output end of the light homogenizing rod further has an output end surface, wherein the output end surface of the output end is an oblique surface formed at the end of the output end, and the output end surface of the output end is perpendicular to the incident end surface of the incident end.

8. The projection module according to claim 1, wherein the light splitting component is glued to the output end, and the light carrying image information reflected by the display chip forms a projection light path through the light splitting component, wherein the projection light path extends obliquely in the direction opposite to the light-uniforming optical axis of the light-uniforming rod to reduce the length of the projection module along the light-uniforming optical axis of the light-uniforming rod.

9. The projection module according to claim 8, wherein the output end further has a light-transmitting area, the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located on an upper end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends upward at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod.

10. The projection module according to claim 8, wherein the output end further has a light-transmitting area, the light-splitting component is glued to the light-transmitting area of ​​the output end, wherein the light-transmitting area is located on a lower end surface of the light-homogenizing rod, and wherein the projection light path formed by the light-splitting component extends downwardly at an angle opposite to the direction of the light-homogenizing optical axis of the light-homogenizing rod. 11 . The projection module according to claim 9 , further comprising a projection lens, wherein the projection lens is arranged at a light emitting end of the light splitting component along the projection light path.

12. The projection module according to claim 11, wherein the spectroscopic component comprises a prism and a spectroscopic film, wherein the prism has a prism incident end face and a prism exit end face, the spectroscopic film is integrally formed on the prism incident end face of the prism, and the imaging light is incident on the prism through the prism incident end face of the prism, and is emitted from the prism exit end face of the prism to the projection lens.

13. The projection module according to claim 11, wherein the incident end of the light homogenizing rod has an incident end surface, wherein the incident end surface is the oblique cut surface formed at the incident end, and the light source and the focusing lens group are located obliquely above the light homogenizing rod to reduce the length of the projection module along the light homogenizing optical axis direction of the light homogenizing rod.

14. The projection module according to claim 13, wherein the focusing lens group comprises a first lens and a second lens, the first lens is located at the front end of the light incident direction of the second lens, and the second lens is a cylindrical lens having optical focal length along the V direction.

Images