Miniature projection light engine module and binocular waveguide system

Abstract

The application discloses a projection light machine module and a waveguide system, wherein the projection light machine module comprises two optical mirror groups which are symmetrically arranged about a symmetry plane, each optical mirror group comprising a first prism and a second prism; image sources of the two optical mirror groups are symmetrically arranged; first light and second light from different image sources are respectively incident into the first prisms of the two optical mirror groups, are emitted out of the first prisms after multiple reflections in the first prisms, are incident into corresponding second prisms, and are emitted out of the second prisms after multiple reflections in the second prisms and are directed to respective exit pupil positions; the exit pupil positions of the two optical mirror groups are located between the two second prisms, and a gap is formed between the two exit pupil positions to accommodate a binocular waveguide sheet. The projection light machine module is matched with the binocular waveguide sheet, and binocular imaging of the waveguide system can be realized, and the image precision is ensured.

Description

Technical Field

[0001] This invention relates to a miniature projection optical engine module, and also to a binocular waveguide system incorporating the miniature projection optical engine module. Background Technology

[0002] Two-dimensional arrayed waveguides are currently the core optical technology for achieving slim and high-performance displays in augmented reality (AR) glasses, and are at a critical stage of moving from the laboratory to large-scale commercial use. The core idea of ​​this technology is to integrate special optical structures inside extremely thin transparent lenses to "expand the pupil" (i.e., enlarge the visible area) the image emitted by a micro-projection optical engine in both the horizontal and vertical dimensions, ultimately projecting a clear and bright virtual image into the human eye.

[0003] In the field of waveguide technology, the micro-projection optical engine is the core display engine of AR glasses, its function being to convert electrical signals into optical images that we can see. Currently, binocular waveguide systems typically employ two independent monocular waveguide systems, one on each side of the support frame. This setup requires precise adjustment of the optical axes of the two monocular waveguide systems during assembly to ensure a proper binocular image for the user. Furthermore, during subsequent use, it is crucial to prevent angular misalignment between the two monocular waveguide systems to avoid affecting binocular vision.

[0004] In addition, in order to ensure the image combination effect of the binocular waveguide system, a solution has emerged in the industry that uses a projection optical engine to drive two waveguide sheets. However, this also has some problems, such as how to ensure that the brightness of the left and right eyes is consistent and how to achieve binocular display differently. Summary of the Invention

[0005] The primary technical problem to be solved by this invention is to provide a miniature projection optical engine module.

[0006] Another technical problem to be solved by the present invention is to provide a binocular waveguide system.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A miniature projection optical engine module includes: two optical lens groups arranged symmetrically about a symmetrical plane, each optical lens group including a first prism and a second prism, wherein the first prism is close to the image source, and the two first prisms are glued together or integrally formed. The image sources of the two optical lens groups are symmetrically arranged about the symmetrical plane; First and second rays from different image sources enter the first prism of two optical lens groups respectively. After multiple reflections in the first prism, they exit the first prism and enter the corresponding second prism. After multiple reflections in the second prism, they exit the second prism and head towards their respective exit pupils. The exit pupils of the two optical lens groups are located between the two second prisms and are symmetrical about the symmetry plane. Both rays of light directed toward the exit pupils are directed toward the symmetry plane, and the center lines of the two rays are on the same straight line. There is a gap between the two exit pupils to accommodate the binocular waveguide sheet.

[0008] Preferably, the image sources of the two optical lens groups are located on the same plane.

[0009] Preferably, the image sources of the two optical lens groups are displayed side by side along the binocular line, and the left image source is vertically flipped relative to the right image source.

[0010] Preferably, there is a gap between the two second prisms to accommodate the binocular waveguide sheet.

[0011] Preferably, the first prism includes a first surface, a second surface, and a third surface, wherein the first surface faces the image source, and the second surface is a composite surface for reflection and transmission; the light emitted from the image source enters from the first surface, is incident on the second surface, is reflected by the second surface, is incident on the third surface, is reflected by the third surface, passes through the second surface and exits the first prism, and is incident on the second prism.

[0012] Preferably, the connecting surfaces of the two first prisms located between the first and second surfaces coincide.

[0013] Preferably, the second surface is close to the plane of symmetry relative to the third surface, so that light rays incident from the first surface to the second surface undergo total internal reflection, and light rays incident from the third surface to the second surface undergo transmission.

[0014] Preferably, the second prism includes a fourth surface, a fifth surface, and a sixth surface, wherein the fourth surface faces the first prism, and the fifth surface is a composite surface for reflection and transmission; light rays from the first prism to the second prism enter from the fourth surface, pass through the fifth surface, are reflected by the fifth surface, pass through the sixth surface, and exit the second prism, and then pass through the fifth surface to the exit pupil position.

[0015] Preferably, the fifth surface is close to the plane of symmetry relative to the sixth surface, so that light rays incident from the fourth surface to the fifth surface undergo total internal reflection, and light rays incident from the sixth surface to the fifth surface undergo transmission.

[0016] A binocular waveguide system, comprising the aforementioned miniature projection optical engine module, further comprising: A binocular waveguide includes a coupling region located in the middle and two coupling out regions located on either side of the coupling region; The coupling region of the binocular waveguide is located between the exit pupil positions of the two optical lens groups; A reflective element is obliquely disposed in the coupling region of the binocular waveguide. Total reflection films are disposed on both sides of the reflective element. The total reflection film located on the front side is used to reflect light rays entering from the front side of the waveguide to the left or right side, and the total reflection film located on the rear side is used to reflect light rays entering from the rear side of the waveguide to the right or left side.

[0017] Preferably, the binocular waveguide further includes two deflection regions disposed on both sides of the coupling region, used to expand and deflect the light from the coupling region in a first direction so that it is directed toward the coupling region, and to expand and couple the light in a second direction through the coupling region.

[0018] Preferably, the image sources of the two optical lens groups are implemented in two separate areas of the same display screen.

[0019] The miniature projection optical engine module provided by this invention includes two optical lens groups symmetrically arranged about a plane perpendicular to the viewing axis. Each optical lens group includes two prisms, and a space for accommodating a binocular waveguide sheet is formed between the exit pupil positions of the two optical lens groups. In this miniature projection optical engine module, the two optical lens groups and their optical paths are completely symmetrical. Combined with the binocular waveguide sheet, it enables binocular imaging of the waveguide system, ensuring image merging accuracy. Furthermore, each of the two optical lens groups has an independent image source, ensuring no interaction or mutual influence between the two light paths, thus enabling binocular differential display. The waveguide system provided by this invention, using the miniature projection optical engine module, is lightweight, compact, and has excellent display performance, making it suitable for a wide range of applications. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the binocular waveguide system provided by the present invention; Figure 2 This is a schematic diagram of the optical path of the micro projection optical engine module provided by the present invention; Figure 3 This is a schematic diagram of the structure of the binocular waveguide sheet provided by the present invention; Figure 4 This is a schematic diagram of the coupling and optical path of the binocular waveguide sheet provided by the present invention; Figure 5 This is a schematic diagram of the screen display direction of the binocular waveguide system provided by the present invention; Figure 6A and Figure 6B This is a schematic diagram of the optical path of the micro projection optical engine module in the first embodiment of the present invention; Figure 7 This is an MTF curve of a single optical lens group in the first embodiment of the present invention; Figure 8 This is a distortion grid diagram of a single optical lens group in the first embodiment of the present invention; Figure 9A and Figure 9B This is a schematic diagram of the optical path of the micro projection optical engine module in the second embodiment of the present invention; Figure 10 This is an MTF curve of a single optical lens group in the second embodiment of the present invention; Figure 11 This is a distortion grid diagram of a single optical lens group in the second embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] To simplify the structure of a binocular waveguide system and reduce the difficulty of binocular waveguide system image merging, this invention provides a miniature projection optical engine module that uses only one display screen to achieve binocular display, and a binocular waveguide system using the miniature projection optical engine module.

[0025] See Figure 1 and Figure 2The micro projection optical engine module includes two mirror-arranged optical lens groups, which are symmetrical about a plane S100 perpendicular to the viewing axis. Each optical lens group includes a first prism and a second prism.

[0026] Two prisms, 1 and 2, form the optical lens group on the left, and two prisms, 3 and 4, form the optical lens group on the right. Figure 2 The left and right correspond to the front and back directions of the human eye's visual axis; the two first prisms 1 and 3 are respectively set close to the image source 5 and 6, and the two first prisms 1 and 3 are glued together or integrally formed; the two second prisms 2 and 4 are far away from the image source, and there is a gap between the two second prisms 2 and 4 to accommodate the binocular waveguide sheet 20.

[0027] The image sources of the two optical lens groups are symmetrically positioned. Preferably, the image sources 5 and 6 of the two optical lens groups are located on the same plane, which can be achieved using two areas of the same micro-display 10. The first and second rays from different image sources enter the first prisms of the two optical lens groups respectively. After multiple reflections in the first prism, they exit the first prism and enter the corresponding second prism. After multiple reflections in the second prism, they exit the second prism and are directed towards their respective exit pupil positions S1 and S2. Each optical lens group and its exit pupil position are located on the same side of the plane of symmetry. The exit pupil positions S1 and S2 of the two optical lens groups are located between the two second prisms 2 and 4 and are symmetrical about the plane of symmetry S100. Both rays directed towards the exit pupil positions are directed towards the plane of symmetry, and the center lines of the two rays are located on the same straight line parallel to the visual axis. There is a gap d between the two exit pupil positions S1 and S2 to accommodate the binocular waveguide 20. The gap d is greater than the thickness D of the binocular waveguide 20.

[0028] The optical paths of the first and second rays within the two optical lens groups are as follows: Figure 2 As shown, the optical path of the first ray in the optical lens group located on the left is used as an example. The optical path of the second ray in the optical lens group located on the right is completely symmetrical to that of the first ray, and will not be described in detail here.

[0029] like Figure 2As shown, the first prism 1 includes a first surface S101, a second surface S102, and a third surface S103. The first surface S101 faces the image source 5, and the second surface S102 is close to the plane of symmetry relative to the third surface S103. The second surface S102 is a composite surface for reflection and transmission. A first ray emitted from the image source 5 enters through the first surface S101, strikes the second surface S102, is reflected by the second surface S102, strikes the third surface S103, is reflected by the third surface S103, passes through the second surface S102, exits the first prism 1, and strikes the second prism 2. The second surface S102 is a composite surface for reflection and transmission; the first ray from the first surface S101 to the second surface S102 undergoes total internal reflection, while the first ray from the third surface S103 to the second surface S102 undergoes transmission.

[0030] The second prism 2 is located below the first prism 1. The second prism 2 includes a fourth surface S104, a fifth surface S105, and a sixth surface S106. The fourth surface S104 faces the first prism 1, and the fifth surface S105 is closer to the symmetry plane S100 relative to the sixth surface S106. The fifth surface S105 is a composite surface for reflection and transmission. The first ray of light incident from the first prism 1 to the second prism 2 enters from the fourth surface S104, strikes the fifth surface S105, is reflected by the fifth surface S105, strikes the sixth surface S106, is reflected by the sixth surface S106, passes through the fifth surface S105, exits the second prism 2, and is directed towards the exit pupil position S1. The first ray of light incident from the fourth surface S104 to the fifth surface S105 undergoes total internal reflection, while the first ray of light incident from the sixth surface S106 to the fifth surface S105 undergoes transmission.

[0031] In the two optical lens assemblies described above, the connecting surface between the first surface S101 and the second surface S102 of the two first prisms 1 and 3 coincides, and this connecting surface coincides with the symmetry plane S100. By bonding the connecting surfaces of the two first prisms 1 and 3 together, or by injection molding the two first prisms 1 and 3 into a single piece, the sharing and overlap of the two connecting surfaces are achieved, thereby ensuring the processing accuracy and image-aligning accuracy of the two optical lens assemblies. Of course, to reduce the mutual interference between the two optical paths, absorption films, reflection films, or structural components are provided on the connecting surfaces of the two prisms to isolate stray light.

[0032] like Figure 1 As shown, the present invention also provides a binocular waveguide system including the aforementioned micro-projection optical engine, which, in addition to the micro-projection optical engine, also includes a binocular waveguide plate 20 perpendicular to the user's visual axis. The aforementioned micro-projection optical engine module is located at the center above the binocular waveguide plate 20.

[0033] like Figure 3 and Figure 4As shown, the binocular waveguide 20 includes a coupling region 109 located in the middle and two output regions 111 and 113 located on both sides of the coupling region 109. The coupling region 109 of the binocular waveguide is located between the exit pupil positions S1 and S2 of the two optical lens groups. A reflective element is provided in the coupling region 109 of the binocular waveguide 20. The reflective element is inclined from front to back in the binocular waveguide 20. Total reflection films are provided on both sides of the reflective element so that the two light rays entering from the front and rear sides of the binocular waveguide 20 are reflected to the left or right respectively.

[0034] The binocular waveguide can be a one-dimensional array waveguide or a two-dimensional array waveguide. A one-dimensional array waveguide includes a central coupling region 109 and two output regions 111 and 113 located on either side of the coupling region 109. The two output regions achieve horizontal pupil expansion and light coupling through beam splitting. A two-dimensional array waveguide includes a central coupling region 109 and two output regions 111 and 113 located on either side of the coupling region 109. It also includes two turning regions 110 and 112 located on either side of the coupling region 109. The turning regions are located in the optical path between the coupling region and the output regions, and are used to divert light from the coupling region to achieve pupil expansion in the first direction (horizontal direction) and to turn it to the output regions. The output regions achieve pupil expansion and light coupling in the second direction (vertical direction) through beam splitting.

[0035] In this invention, to facilitate the design and description of the micro-projection optical engine module and the binocular waveguide, coordinate systems are established for both. For the binocular waveguide, a three-dimensional Cartesian coordinate system is established with the upper center of the waveguide as the origin. The horizontal direction is the X-axis, with the horizontal direction to the right being positive; the viewing axis is the Y-axis (facing the viewer's eye is positive, i.e., the direction of light emanating from the waveguide is positive); and the vertical direction is the Z-axis, with vertical downwards being positive. A one-dimensional waveguide achieves X-direction extension through the coupling region; a two-dimensional waveguide achieves X-direction extension through the steering region and Z-direction extension through the coupling region.

[0036] Combination Figures 1 to 5 The optical path principle of the waveguide system provided by this invention will be introduced. An example will be given where the image source 5 and the first optical mirror group are located behind the binocular waveguide 20, and the image source 6 and the second optical mirror group are located in front of the binocular waveguide 20.

[0037] The first ray emitted from image source 5 (represented by a dark solid line in the figure) strikes the first prism 1. After multiple reflections within the first prism 1, it exits the first prism 1 and enters the corresponding second prism 2. After multiple reflections within the second prism 2, it exits the second prism 2 and strikes the exit pupil position S1. It then enters the binocular waveguide 20 from the rear side of the coupling region 109. After being reflected in the coupling region 109, the first ray propagates horizontally to the left. Then, through the beam splitting effect of the turning region 110, it achieves horizontal pupil dilation and turns to the coupling region 111. Under the beam splitting effect of the coupling region 111, it achieves vertical pupil dilation and exits the binocular waveguide 20, striking the left eye for imaging.

[0038] The second ray emitted from image source 6 (represented by a light-colored solid line in the figure) strikes the first prism 3. After multiple reflections within the first prism 3, it exits the first prism 3 and enters the corresponding second prism 4. After multiple reflections within the second prism 4, it exits the second prism 4 and strikes the exit pupil position S2. It then enters the binocular waveguide 20 from the front of the coupling region 109. After being reflected in the coupling region 109, the second ray propagates horizontally to the right. Then, through the beam splitting effect of the turning region 112, it achieves horizontal pupil dilation and turns to the coupling region 113. Under the beam splitting effect of the coupling region 113, it achieves vertical pupil dilation and exits the binocular waveguide 20, striking the right eye for imaging.

[0039] In the aforementioned binocular waveguide system, the two image sources and two optical lens groups are symmetrical with respect to the symmetry plane S100. The two exit pupil positions S1 and S2 are also symmetrical with respect to the symmetry plane S100. The binocular waveguide 20 is located on the symmetry plane S100. The first and second rays enter the waveguide from the front and rear sides in a completely symmetrical manner. The mirrors in the coupling region of the binocular waveguide 20 can reflect the second ray from the front to the right and the first ray from the rear to the left. In the binocular waveguide 20, the turning regions 110 and 112 are symmetrical with respect to the Z-axis, and the coupling regions 111 and 113 are also symmetrical with respect to the Z-axis. Therefore, the propagation patterns of the first and second rays within the binocular waveguide are also completely symmetrical, enabling precise binocular image combining.

[0040] In this binocular waveguide system, although the image sources 5 and 6 of the first and second light rays can be realized by different areas of the same display screen 10, the image sources of the first and second light rays, as well as the optical mirror groups on the transmission path, are completely independent. Therefore, two different image sources can be provided to the binocular waveguide sheet respectively. Thus, the above-mentioned binocular waveguide system can realize the function of binocular differential display. In order to reduce the mutual influence between the two optical paths, the two image sources can be implemented using screens with small emission angles, and a certain area can be reserved between the two image sources without display.

[0041] Figure 5 The diagram illustrates the correspondence between the screen display and the image seen by the human eye. The images observed by the left and right eyes are identical; the left and right image sources satisfy the requirement of binocular merging, and are positioned side-by-side along the line connecting the corresponding eyes on the same display screen (arranged from front to back). The image from the right eye is vertically flipped relative to the image from the left eye. Based on this, a 3D effect can be achieved through the difference in binocular display. Thus, the binocular waveguide system provided by this invention enables the display of binocularly differentiated images using a single display screen.

[0042] The following provides two typical implementation methods to illustrate the imaging effect of the present invention. In the micro-projection optical engine module, the optical surfaces of the prisms in the two optical lens groups can be spherical, aspherical, or freeform, preferably aspherical or freeform, to achieve miniaturization while reducing aberrations.

[0043] First embodiment: The miniature projection optical engine module in the first embodiment is described below. For example... Figure 6A and Figure 6B The optical mechanism shown consists of two optical mirror groups arranged in a mirror image. One group consists of prisms 11 and 12, and the other group consists of prisms 13 and 14 arranged in a mirror image. A waveguide plate 16 is placed between the two optical mirror groups. The display screen 15 is symmetrically divided into two parts. The first light ray and the second light ray are emitted from the left and right parts of the display screen 15, respectively. The mirror group in front of each display area can convert the display screen image into parallel light with different fields of view. The screen display area used by a single mirror group is 1.45mm × 1.45mm, and the field of view is a square with a diagonal angle of 20 degrees. The inner surfaces of prisms 11, 12, 13, and 14 (i.e., the second surface 104 and the fifth surface 101) are multiplexed transmission and reflection surfaces, and the outer surfaces of prisms 11, 12, 13, and 14 (i.e., the third surface 105 and the sixth surface 102) need to be coated with a reflective film.

[0044] The specific light path is as follows: After being emitted from the screen 108, the light passes through the protective glass surface 107, is transmitted through the first surface 106 into the prism 14, undergoes total internal reflection on the second surface 104, is reflected on the third surface 105, and then is transmitted through the second surface 104 out of the prism 14; it is also transmitted through the fourth surface 103 into the prism 13, undergoes total internal reflection on the fifth surface 101, is reflected on the sixth surface 102, and then is transmitted horizontally through the fifth surface 101 out of the prism 13, and finally enters the binocular waveguide 16 through the exit pupil 100.

[0045] The exit pupils of the two optical lens groups are parallel and opposite, with their exit pupil surfaces forming a 90° angle with screen 108. A gap exists between the two exit pupil surfaces to accommodate the waveguide sheet. In this embodiment, considering the need for protective frames to be attached to the front and back of the waveguide sheet, the distance between the two exit pupils is 4mm. The size of the exit pupils is 4mm. The rectangular outer envelope dimensions of the entire optomechanical optical section are 12mm * 18.5mm * 5mm. Where 12mm is... Figure 6A Medium horizontal dimension (corresponding to) Figure 5 (Y-axis in the middle), 18.5mm is Figure 6A The vertical dimension (corresponding to) Figure 5 (Z-axis in the middle), 5mm is Figure 6A The thickness dimension perpendicular to the paper surface (corresponding to) Figure 5 (X-axis in the diagram).

[0046] Table 1 below describes the surface profiles of an optical lens assembly in the first embodiment. A positive radius of curvature indicates that the center of the surface curvature circle is behind the surface along the direction of light propagation, while a negative radius of curvature indicates that the center of the surface curvature circle is in front of the surface along the direction of light propagation. Table 2 below shows the coefficients for the aspherical surfaces.

[0047] Table 1. Surface type and radius of curvature of each surface in the first embodiment. Table 2 gives the coefficients of each aspherical surface. The equations of the aspherical surface types are as follows:

[0048] Table 2 Aspheric coefficients of each aspheric surface in the first embodiment

[0049] Table 3 below establishes a three-dimensional rectangular coordinate system for the optical lens assembly, with the exit pupil center as the origin, describing the positions of various surfaces within the optical lens assembly. The right side of the exit pupil is the positive z-axis, the top of the exit pupil is the positive y-axis, and the direction perpendicular to the paper and pointing inwards is the positive x-axis.

[0050] Table 3 shows the positions of each surface in the first embodiment.

[0051] Figure 7 and Figure 8 The figures show the MTF curves and distortion of a single optical lens group in the micro-projection optical engine module. As can be seen from the figures, the MTF of this optical lens group is greater than 0.2 at the 45 line pair, and the distortion is less than 3%.

[0052] The micro projection optical engine module of the present invention has multiple prisms that can correct system aberrations. The near-eye display system using this optical lens group has a better imaging effect. It can realize binocular display with only one screen, which saves costs and is easy to promote and use.

[0053] The following is combined with Figure 3 and Figure 4 This section introduces the waveguide component of a binocular waveguide system. It details the structure of the binocular waveguide plate 16. Figure 3 The waveguide structures shown are identical. The binocular waveguide 16 consists of symmetrically arranged pupil-expanding regions 110 and 112 on both sides, coupling-out regions 111 and 113, and an embedded reflective coupling-in surface 109 located in the middle. After the exit pupil of the micro-projection optical engine module is aligned with the coupling-in region, the parallel light emitted from the two optical mirror groups of the micro-projection optical engine module is reflected by the embedded reflective coupling-in surface 109 of the waveguide. One beam propagates to the left and the other to the right, respectively, and enters the human eye after passing through the left and right pupil-expanding regions 110 and 112 and the coupling-out pupil-expanding regions 111 and 113. Figure 4 The propagation direction of light from the micro-projection optical engine module in the binocular waveguide is given. Optical engine direction one represents the direction of parallel light emitted from one optical lens group in the micro-projection optical engine module. Optical engine direction two represents the direction of parallel light emitted from the opposite optical lens group. The light from optical engine direction one is reflected by the reflective coupling surface 109, propagates to the right, and finally couples out into the observer's right eye. The light from optical engine direction two is reflected by the reflective coupling surface 109, propagates to the left, and finally couples out into the observer's left eye. Of course, by adjusting the setting direction of the reflective coupling surface 109, the light from optical engine direction one can also be reflected by the reflective coupling surface 109, propagates to the left, and finally couples out into the observer's left eye, while the light from optical engine direction two is reflected by the reflective coupling surface 109, propagates to the right, and finally couples out into the observer's right eye. Thus, the system of this embodiment realizes the display of binocular difference images using a single display screen.

[0054] Second embodiment: In this embodiment, replacing the aspherical and spherical surfaces of the optical engine in Embodiment 1 with freeform surfaces can further improve image quality. For example... Figure 9A and Figure 9B This is a schematic diagram of the optical engine structure in the second embodiment. The overall size of the micro-projection optical engine system is further reduced to 11.6mm*17.5mm*4.7mm.

[0055] Table 4 below shows the global coordinates of each surface of a lens group in the second embodiment. The origin of the coordinates is the exit pupil 200, where the right side of the exit pupil is the positive z-axis, the top of the exit pupil is the positive y-axis, and the direction perpendicular to the paper and inward is the positive x-axis.

[0056] Table 4 Surface position and orientation in the second embodiment

[0057] Table 5 below describes the surface profiles of each surface.

[0058] Table 5. Surface type and radius of curvature of each surface in the second embodiment. The freeform surface shape can be described using XY polynomials, as shown in the following equations: Table 6 below describes the XY polynomial coefficients for surfaces 201 to 206.

[0059] Table 6. Polynomial coefficients of XY on surfaces 201–206 Figure 10 and Figure 11 The figures show the MTF curves and distortion of a single lens group in the optical engine. As can be seen from the figures, the MTF of this optical lens group is greater than 0.4 at 60 line pairs, and the distortion is less than 1%. Compared with the first embodiment, the micro-projection optical engine module uses a freeform surface design, which can improve the MTF, reduce distortion, and further reduce the size.

[0060] The micro projection optical engine module of the present invention includes two optical lens groups arranged symmetrically about a symmetrical plane. Each optical lens group includes two prisms, which can correct system aberrations. The near-eye display system using the optical lens group has a better imaging effect. It can realize binocular display with only one screen, which saves costs and is easy to promote and use.

[0061] The miniature projection optical engine module provided by this invention includes two optical lens groups symmetrically arranged about a symmetrical plane. A space for accommodating a binocular waveguide sheet is formed between the exit pupil positions of the two optical lens groups. Combined with the binocular waveguide sheet, binocular imaging of the waveguide system can be achieved in a "one-to-two" manner, ensuring image merging accuracy. The waveguide system provided by this invention, using the projection optical engine module provided by this invention, is lightweight, compact, has excellent display effects, and has a wide range of applications. Furthermore, it can achieve binocular display with only one screen, saving costs and being easy to promote and use.

[0062] The foregoing has provided a detailed description of the miniature projection optical engine module and binocular waveguide system provided by this invention. Any obvious modifications made by those skilled in the art without departing from the essential content of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A projection optical engine module, characterized in that... include: Regarding two optical lens groups arranged symmetrically, each optical lens group includes a first prism and a second prism, wherein the first prism is close to the image source, and the two first prisms are glued together or integrally formed. The image sources of the two optical lens groups are positioned symmetrically. First and second rays from different image sources enter the first prism of two optical lens groups respectively. After multiple reflections in the first prism, they exit the first prism and enter the corresponding second prism. After multiple reflections in the second prism, they exit the second prism and head towards their respective exit pupils. The exit pupils of the two optical lens groups are located between the two second prisms and are symmetrical about the symmetry plane. Both rays of light directed toward the exit pupils are directed toward the symmetry plane, and the center lines of the two rays are on the same straight line. There is a gap between the two exit pupils to accommodate the binocular waveguide sheet.

2. The projection optical engine module as described in claim 1, characterized in that: The image sources of the two optical lens groups are located on the same plane.

3. The projection optical engine module as described in claim 1 or 2, characterized in that: The image sources of the two optical lens groups are displayed side by side along the binocular line, and the left image source is vertically flipped relative to the right image source.

4. The projection optical engine module as described in claim 1 or 2, characterized in that: There is a gap between the two second prisms to accommodate the binocular waveguide sheet.

5. The projection optical engine module as described in claim 4, characterized in that: The first prism includes a first surface, a second surface, and a third surface. The first surface faces the image source, and the second surface is a composite surface for reflection and transmission. Light emitted from the image source enters from the first surface, travels to the second surface, is reflected by the second surface, travels to the third surface, is reflected by the third surface, passes through the second surface, exits the first prism, and travels to the second prism.

6. The projection optical engine module as described in claim 5, characterized in that: In the two first prisms, the connecting surface located between the first surface and the second surface coincides.

7. The projection optical engine module as described in claim 5, characterized in that: The second surface is close to the plane of symmetry with respect to the third surface. Light rays incident from the first surface to the second surface undergo total internal reflection, while light rays incident from the third surface to the second surface undergo transmission.

8. The projection optical engine module as described in claim 5, characterized in that: The second prism includes a fourth surface, a fifth surface, and a sixth surface. The fourth surface faces the first prism, and the fifth surface is a composite surface for reflection and transmission. Light rays from the first prism to the second prism enter through the fourth surface, pass through the fifth surface, are reflected by the fifth surface, pass through the sixth surface, and exit the second prism, heading towards the exit pupil.

9. The projection optical engine module as described in claim 8, characterized in that: The fifth surface is close to the plane of symmetry relative to the sixth surface. Light rays incident from the fourth surface to the fifth surface undergo total internal reflection, while light rays incident from the sixth surface to the fifth surface undergo transmission.

10. A binocular waveguide system, comprising the projection optical engine module as described in any one of claims 1-9, characterized in that... Also includes: A binocular waveguide includes a coupling region located in the middle and two coupling out regions located on either side of the coupling region; The coupling region of the binocular waveguide is located between the exit pupil positions of the two optical lens groups; A reflective element is provided in the coupling region of the binocular waveguide, and a total reflection film is provided on both sides of the reflective element so that the two light rays entering from the front and rear sides of the waveguide are reflected to the left and right sides respectively.

11. The binocular waveguide system as described in claim 10, characterized in that: The binocular waveguide also includes two turning regions disposed on both sides of the coupling region, which are used to turn the light from the coupling region, after pupil dilation in the first direction, to the coupling region, and achieve pupil dilation in the second direction through the coupling region.

12. The binocular waveguide system as described in claim 10, characterized in that: The image sources of the two optical lens groups are realized in two separate areas on the same display screen.

Images