Projection optical engines and AR optical display devices

Abstract

This application provides a projection optical engine and an AR optical display device. The projection optical engine includes a PBS prism, a first prism and a fourth prism disposed on opposite sides of the PBS prism, and a second reflective element and a third reflective element disposed on opposite sides of the PBS prism. A first PBS film is provided on the light-incident side of the first prism, and a first reflective element is provided on the reflected light path of the first PBS film. A first phase retarder is provided between the first prism and the PBS prism. The PBS prism includes a second prism and a third prism. A second PBS film is provided between the second prism and the third prism. A second reflective element is located on one side of the second prism, and a second phase retarder is provided between the two. The second reflective element is used to reflect the first polarized light reflected by the second PBS film. A third reflective element is located on one side of the third prism, and a third phase retarder is provided between the two. The third reflective element is used to reflect the second polarized light projected by the second PBS film.

Description

Technical Field

[0001] This application relates to the field of projection display technology, and more specifically, to a projection optical engine and an AR optical display device. Background Technology

[0002] In the XR and micro-projection fields, LCOS technology has become one of the mainstream projection optical engine technologies due to its mature process, high brightness, and relatively small size. However, LCOS projection optical engines need to convert natural light into polarized light during operation. This conversion process often involves a significant loss of light energy, resulting in low overall light energy utilization efficiency of the projection optical engine. This, in turn, increases the power consumption of the projection optical engine, which is detrimental to the lightweight design and energy efficiency improvement of the device.

[0003] Traditional LCOS projection optical engines often use a single polarization conversion element in their optical path design, such as a polarization beam splitter (PBS) or a polarization conversion film. While these elements convert the polarization state of light, some light energy will inevitably be reflected or absorbed, thereby reducing the overall utilization rate of light energy. Summary of the Invention

[0004] The purpose of this application is to provide a new technical solution for a projection optical engine and an AR optical display device.

[0005] In a first aspect, this application provides a projection optical engine. The projection optical engine includes a PBS prism, a first prism and a fourth prism respectively disposed on opposite sides of the PBS prism, and a second reflective element and a third reflective element respectively disposed on opposite sides of the PBS prism;

[0006] The first prism has a first PBS film on its incident light side and a first reflective element on the reflected light path of the first PBS film. A first phase delayer is provided between the first prism and the PBS prism.

[0007] The PBS prism includes a second prism and a third prism. A second PBS film is disposed between the second prism and the third prism. A second reflective element is located on one side of the second prism and a second phase delayer is disposed between them. The second reflective element is used to reflect the first polarized light reflected by the second PBS film. The third reflective element is located on one side of the third prism and a third phase delayer is disposed between them. The third reflective element is used to reflect the second polarized light projected by the second PBS film.

[0008] Optionally, the projection optical engine includes an imaging chip disposed on the side of the fourth prism away from the PBS prism. The imaging chip is used to modulate the first polarized light reflected by the second PBS film into second polarized light and reflect it into the fourth prism.

[0009] Optionally, the fourth prism is a right-angle prism, with one right-angle face of the fourth prism close to the imaging chip, and the inclined face of the fourth prism close to the PBS prism. The inclined face of the fourth prism forms a total internal reflection surface, which is used to reflect the second polarized light modulated by the imaging chip to the other right-angle face of the fourth prism for exit.

[0010] Optionally, the first prism is a right-angle prism, the light-incident surface of the first prism is an inclined plane, the first PBS film is disposed on the light-incident surface, and the first phase delayer is disposed on the surface of the first prism near the PBS prism.

[0011] Optionally, the first phase delayer is a half-wave plate.

[0012] Optionally, the first reflective element is a plane mirror, which is arranged parallel to the light-incident surface of the first prism. The first reflective element is used to reflect the first polarized light reflected by the first PBS film to the second PBS film.

[0013] Optionally, the second prism and the third prism are right-angle prisms, the inclined surfaces of the second prism and the third prism are glued together, and a second PBS film that transmits second polarized light and reflects first polarized light is disposed between the inclined surfaces of the second prism and the third prism.

[0014] Optionally, the second prism includes a first right-angled surface and a second right-angled surface, the first right-angled surface is close to the first prism, the second phase retarder is disposed on the second right-angled surface, and the second reflective element is disposed on the second phase retarder;

[0015] The third prism includes a third right-angled surface and a fourth right-angled surface. The third right-angled surface is close to the fourth prism. The third phase retarder is disposed on the fourth right-angled surface. The third reflective element is disposed on the third phase retarder.

[0016] Optionally, the second phase delayer and the third phase delayer are quarter-wave plates.

[0017] Optionally, the second reflective element and the third reflective element are curved reflective mirrors, and the surfaces of the second reflective element and the third reflective element that are away from the PBS prism are curved.

[0018] Optionally, the first polarized light is S-polarized light, and the second polarized light is P-polarized light.

[0019] Secondly, this application provides an AR optical display device, the AR optical display device comprising:

[0020] The outer casing; and

[0021] As described in the first aspect, the projection optical engine.

[0022] The beneficial effects of this application are as follows:

[0023] This application provides a novel structure for a projection optical engine based on LCOS display. By introducing a combination of a phase retarder and a reflector, along with a PBS film, it achieves efficient polarization conversion of natural light, minimizing light energy loss during the conversion process and improving the overall light energy utilization of the optical engine. Due to the improved light energy utilization, the electrical energy consumed by the projection optical engine during operation is correspondingly reduced, thereby helping to reduce the overall power consumption of the projection optical engine. In addition, the special optical architecture design makes the projection optical engine have a relatively compact structure.

[0024] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0026] Figure 1 This is a schematic diagram of a projection optical engine provided in an embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. First PBS membrane; 2. First prism; 3. First phase delayer; 4. First reflective element; 5. Second prism; 6. Second reflective element; 7. Second phase delayer; 8. Second PBS membrane; 9. Third prism; 10. Third phase delayer; 11. Third reflective element; 12. Fourth prism; 13. Imaging chip. Detailed Implementation

[0029] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0031] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0032] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0034] The projection optical engine and AR optical display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0035] According to one embodiment of this application, a projection optical engine is provided, see [link to relevant documentation]. Figure 1 The projection optical engine includes a PBS prism, and a first prism 2 and a fourth prism 12 respectively disposed on opposite sides of the PBS prism, and a second reflective element 6 and a third reflective element 11 respectively disposed on opposite sides of the PBS prism; a first PBS film 1 is provided on the light incident side of the first prism 2, and a first reflective element 4 is provided on the reflected light path of the first PBS film 1, and a first phase delay 3 is provided between the first prism 2 and the PBS prism; the PBS prism includes a second prism 5 and a third prism 9, a second PBS film 8 is provided between the second prism 5 and the third prism 9, the second reflective element 6 is located on one side of the second prism 5 and a second phase delay 7 is provided between the two, the second reflective element 6 is used to reflect the first polarized light reflected by the second PBS film 8, the third reflective element 11 is located on one side of the third prism 9 and a third phase delay 10 is provided between the two, the third reflective element 11 is used to reflect the second polarized light projected by the second PBS film 8.

[0036] The projection optical engine provided in this application embodiment has an optical architecture design that achieves efficient polarization separation and redirection of incident light through the precise layout and coordination of a series of optical components such as PBS prisms, multiple prisms, reflective elements, PBS films, and phase retarders.

[0037] The projection optical engine provided in this application includes a PBS prism, also known as a polarizing beam splitter prism, which separates or combines light rays according to their polarization state (such as S-polarized light and P-polarized light). In this application, the PBS prism consists of a second prism 5 and a third prism 9, with a second PBS film 8 sandwiched between them for precise control of the polarization separation and beam combining of the incident light rays.

[0038] It should be noted that the first polarized light mentioned in the embodiments of this application is, for example, S-polarized light, and the second polarized light is, for example, P-polarized light.

[0039] The projection optical engine provided in this embodiment includes a first prism 2 and a fourth prism 12. See [link to relevant documentation] Figure 1 From an optical architecture design perspective, the two prisms are located on opposite sides of the PBS prism, primarily serving to guide the light path. A first PBS film 1 is disposed on the incident light side of the first prism 2 to initially separate the polarization state of the incident light. The fourth prism 12 is located on the side closer to the imaging chip 13, and its main function is to further guide the light path or shape the beam. The projected light emitted through the fourth prism 12 can be transmitted to the human eye for imaging via, for example, a diffractive waveguide device.

[0040] The projection optical engine provided in this embodiment includes a first PBS film 1, which is a polarizing beam splitter. From the perspective of the placement position of the first PBS film 1, it is located on the light-incident side of the first prism 2, and is responsible for separating the S-polarized light (referred to as the first polarized light in the above description) and the P-polarized light (referred to as the second polarized light in the above description) of the incident light (such as natural light). Specifically, see... Figure 1 S-polarized light is reflected by the first PBS film 1, while P-polarized light can be directly transmitted through the first PBS film 1 and enter the subsequent optical path.

[0041] The projection optical engine provided in this application embodiment includes a first reflective element 4, which is disposed in the reflected light path of the first PBS film 1 and is used to change the propagation direction of S-polarized light (i.e., first polarized light) and guide it into the subsequent optical processing path.

[0042] The projection optical engine provided in this application embodiment includes a first phase delay unit 3, which is located between the first prism 2 and the PBS prism. By introducing a specific phase delay, the phase of the P-polarized light (second polarized light) transmitted through the first PBS film 1 is changed, thereby realizing the conversion of the P-polarized light (second polarized light) into S-polarized light (first polarized light).

[0043] The projection optical engine provided in this embodiment includes a second PBS film 8, which is located between the second prism 5 and the third prism 9. The second PBS film 8 is a crucial optical element in the PBS prism, primarily used to further separate or combine polarized light from different paths. The P-polarized light (second polarized light) initially separated by the first PBS film 1 and the reflected S-polarized light (first polarized light) are further separated or combined here according to their polarization states (light with the same polarization state is combined).

[0044] The projection optical engine provided in this embodiment includes a second reflective element 6 and a third reflective element 11. See [link to documentation]. Figure 1These two reflective elements are located on one side of the second prism 5 and the third prism 9, respectively, and are arranged opposite to each other to reflect polarized light treated by the second PBS film 8. By adjusting the direction of light propagation, these two reflective elements allow the light path to follow a predetermined path, achieving the redirection and integration of light rays.

[0045] The projection optical engine provided in this embodiment includes a second phase delay unit 7 and a third phase delay unit 10. See [link to relevant documentation]. Figure 1 The second phase delayer 7 is located between the second prism 5 and the second reflective element 6, and the third phase delayer 10 is located between the third prism 9 and the third reflective element 11. By introducing phase delay, the phase of the reflected light is adjusted to ensure that the light on different paths can be successfully combined in subsequent optical processing to achieve a good imaging effect.

[0046] The projection optical engine provided in this application embodiment employs PBS (polarized beam splitting) technology, specifically by using the first PBS film 1 to perform preliminary polarization separation of incident light on the light-incident side of the first prism 2. This design allows for the effective separation of different polarization components (such as S-polarized light and P-polarized light) in incident light (such as natural light), providing a foundation for subsequent optical processing.

[0047] The projection optical engine provided in this application embodiment, by setting the first reflective element 4 on the reflected light path of the first PBS film 1, can flexibly control the path of the reflected light, thereby realizing the adjustment and optimization of the optical path. Similarly, the second reflective element 6 and the third reflective element 11 are respectively located on the other opposite sides of the PBS prism, see [link to relevant documentation]. Figure 1 It is used to reflect different polarized light after being separated by the second PBS membrane 8.

[0048] The projection optical engine provided in this application embodiment has a first phase retarder 3, a second phase retarder 7, and a third phase retarder 10 respectively disposed between the first prism 2 and the PBS prism, between the second reflective element 6 and the second prism 5, and between the third reflective element 11 and the third prism 9. These phase retarders can precisely adjust the phase of the polarized light passing through them, which helps to correct the phase difference introduced by the optical elements, ensure the coherence and stability of the beam, and thus improve the sharpness and color accuracy of the projected image.

[0049] The projection optical engine provided in this application embodiment has a compact structure. Each optical element is arranged around the PBS prism, which not only realizes the separation and redirection of polarized light, but also minimizes the optical path length, which helps to reduce the size of the projection optical engine and reduce manufacturing costs.

[0050] In summary, the embodiments of this application provide a novel structure for a projection optical engine based on LCOS display. By introducing a combination of a phase retarder and a reflector, and combining it with a PBS film, efficient polarization conversion of natural light is achieved, which can minimize the loss of light energy during the conversion process and improve the overall light energy utilization of the optical engine. Due to the improved light energy utilization, the electrical energy consumed by the projection optical engine during operation will be reduced accordingly, thereby helping to reduce the overall power consumption of the projection optical engine. In addition, the special optical architecture design makes the projection optical engine have a relatively compact structure.

[0051] See some examples in this application. Figure 1 The projection optical engine includes an imaging chip 13, which is disposed on the side of the fourth prism 12 away from the PBS prism. The imaging chip 13 is used to modulate the first polarized light reflected by the second PBS film 8 into second polarized light and reflect it into the fourth prism 12.

[0052] The projection optical engine provided in this application embodiment integrates an imaging chip 13, which is, for example, an LCOS (Liquid Crystal on Silicon) chip.

[0053] LCOS chips, with their tiny pixel size and precise manufacturing process, are capable of generating high-definition images. In the projection optical engine of this embodiment, an LCOS chip is used as the imaging chip 13, which means that the projected image will have more detail and less pixelation, thus providing a more realistic and delicate visual experience.

[0054] LCOS chips display images by precisely controlling the transmittance of the liquid crystal layer. This control method gives LCOS display technology high contrast. In the image processing system provided in this application embodiment, high contrast can significantly enhance the sense of layering and depth of the image, making dark details clearer and bright areas more vivid.

[0055] Because the LCOS chip directly modulates light rather than emitting light through a backlight panel, its light utilization rate is relatively high. In the projection optical engine provided in this application embodiment, this means that more light can be effectively utilized to form an image, thereby improving the brightness and color saturation of the projection.

[0056] In this example of the application, the projection optical engine integrates an imaging chip 13, which is cleverly placed on the side of the fourth prism 12 opposite to the PBS prism. This arrangement not only optimizes the optical path design but also fully utilizes the imaging chip 13's capabilities in modulating and reflecting light.

[0057] Specifically, see Figure 1The imaging chip 13 receives S-polarized light (first polarized light) reflected from the second PBS film 8, a crucial step in the light processing of the optical path. Through pixel control and liquid crystal layer modulation within the imaging chip 13, the S-polarized light (first polarized light) is precisely modulated into P-polarized light (second polarized light). This modulation process not only maintains the brightness of the light but also ensures that the polarization state of the light meets the requirements of the subsequent optical path.

[0058] The modulated P-polarized light (second polarized light) is reflected by the imaging chip 13 into the fourth prism 12. This direct reflection method reduces intermediate links in the optical path, lowers light loss, and improves light transmission efficiency. Simultaneously, due to the close arrangement between the imaging chip 13 and the fourth prism 12, light can enter the fourth prism 12 with high precision and angle, preparing for subsequent optical path deflection and projection imaging.

[0059] The imaging chip 13 serves as a polarization modulation element, enabling control of the polarization state of light.

[0060] The high resolution and precise modulation capabilities of the imaging chip 13 ensure high definition of the projected image. Simultaneously, because light loss is minimal during transmission between the imaging chip 13 and the fourth prism 12, the brightness and color saturation of the projected image are also enhanced. This high-quality projection effect provides users with a more realistic and comfortable viewing experience.

[0061] See some examples in this application. Figure 1 The fourth prism 12 is a right-angle prism. One right-angle face of the fourth prism 12 is close to the imaging chip 13, and the inclined face of the fourth prism 12 is close to the PBS prism. The inclined face of the fourth prism 12 forms a total internal reflection surface, which is used to reflect the second polarized light modulated by the imaging chip 13 to the other right-angle face of the fourth prism 12 for emission.

[0062] See the examples in this application. Figure 1 The fourth prism 12 is designed as a right-angle prism, cleverly utilizing its geometric properties to achieve the refraction and reflection of light. Specifically, one right-angled surface of the fourth prism 12 is close to the imaging chip 13 (the two are parallel) and is used to receive the P-polarized light (second polarized light) modulated by the imaging chip 13; while the inclined surface of the fourth prism 12 is close to the PBS prism and is designed as a total internal reflection surface to reflect the received P-polarized light (second polarized light) at a specific angle. This design not only simplifies the optical path structure but also improves the efficiency of light utilization.

[0063] By employing a right-angle prism design, the fourth prism 12 achieves efficient light refraction. The P-polarized light (second polarized light) reflected by the imaging chip 13 is directly transmitted through one right-angled surface of the fourth prism 12, then undergoes total internal reflection via an inclined plane, and finally exits at a predetermined angle from the other right-angled surface of the fourth prism 12. This refraction method reduces the number of components in the optical path, lowers light loss, and improves light transmission efficiency.

[0064] Because the inclined surface of the fourth prism 12 is designed as a total reflection surface, it ensures that no energy loss or change in polarization state occurs during light reflection. This precise light control helps maintain image sharpness and color accuracy, avoiding image blurring or color distortion caused by light scattering or changes in polarization state.

[0065] See some examples in this application. Figure 1 The first prism 2 is a right-angle prism, the light-incident surface of the first prism 2 is an inclined surface, the first PBS film 1 is disposed on the light-incident surface, and the first phase delayer 3 is disposed on the surface of the first prism 2 near the PBS prism.

[0066] See the examples in this application. Figure 1 The first prism 2 is a right-angle prism, and its incident surface is designed as a bevel for use in conjunction with the first PBS film 1. Simultaneously, the first phase retarder 3 is placed on the surface of the first prism 2 near the PBS prism. This arrangement not only optimizes the optical path structure but also enables further control and processing of the light by introducing the phase retarder.

[0067] The first prism 2 has an inclined incident surface and is combined with the first PBS film 1 to efficiently separate different polarization components in incident light (such as natural light). The first PBS film (polarizing beam splitter) has the ability to split the incident light into two perpendicular polarization components, while the inclined design helps ensure that the light is incident on the first PBS film 1 at the correct angle, thereby improving the separation efficiency.

[0068] The first phase delayer 3 is directly adhered to the surface of the first prism 2 near the PBS prism. It can perform phase delay processing on light rays of a specific polarization state, such as P-polarized light (second polarized light), after being separated by the first PBS film 1, thereby transforming S-polarized light (first polarized light). Here, the first phase delayer can precisely control the phase difference of P-polarized light (second polarized light), thereby achieving further modulation and correction of the polarization state of the light.

[0069] By integrating a first phase retarder 3 onto the first prism 2, the polarization state distribution of light in the projection optical engine can be optimized. In projection displays, light with different polarization states has a significant impact on the contrast and color performance of the projected image. By precisely controlling the polarization state of light, the contrast of the projected image can be improved, making the image more vivid and realistic.

[0070] The integrated design of the first prism 2, the first PBS film 1, and the first phase delayer 3 in this example achieves efficient light separation, precise light guidance, accurate control of phase delay, and improved contrast of the projected image. This design not only improves the overall performance of the projection optical engine but also enhances the stability and reliability of the system, providing strong support for high-quality projection displays.

[0071] See some examples in this application. Figure 1 The first phase delayer 3 is a half-wave plate.

[0072] A half-wave plate (HWP film) is a special type of phase retarder that can rotate the polarization direction of incident light by 90 degrees without changing the direction of light propagation.

[0073] As a half-wave plate, the first phase retarder 3 can precisely rotate the light rays of a specific polarization state separated by the first PBS film 1 by 90 degrees. This polarization rotation capability is particularly important in applications that require adjustment of the polarization direction of light to meet the requirements of subsequent optical paths. For example, in a projection optical engine, by rotating the polarization direction of the light, it can be ensured that the light can be correctly processed by subsequent polarization elements (such as the second PBS film 8).

[0074] In projection optical engines, proper control of the polarization state is crucial for the quality of the projected image. A half-wave plate, as a precise polarization rotation element, ensures that the polarization state of light remains stable during transmission, avoiding problems such as image blurring and color distortion caused by changes in polarization state. Therefore, using a half-wave plate can improve the sharpness and color accuracy of the projected image.

[0075] See some examples in this application. Figure 1 The first reflective element 4 is a plane mirror, which is arranged parallel to the light-incident surface of the first prism 2. The first reflective element 4 is used to reflect the first polarized light reflected by the first PBS film 1 to the second PBS film 8.

[0076] In the example of this application, the first reflective element 4 is, for example, a plane mirror, and is arranged parallel to the light-incident surface of the first prism 2. The main function of this plane mirror is to reflect the S-polarized light (first polarized light) reflected by the first PBS film 1 to the second PBS film 8, which can minimize the loss of light energy when natural light is converted into S-polarized light.

[0077] By placing a plane mirror parallel to the light-incident surface of the first prism 2, the light path can be redirected without increasing space requirements. This compact light path design is particularly important for optical systems that require strict size control (such as projection engines).

[0078] The position and angle of a plane mirror can be adjusted according to actual needs, thus flexibly changing the direction and path of reflected light. Plane mirrors have high reflectivity, therefore minimizing light loss during reflection. Plane mirrors also have the advantages of simple structure and ease of manufacture.

[0079] See some examples in this application. Figure 1 The second prism 5 and the third prism 9 are right-angle prisms. The inclined surfaces of the second prism 5 and the third prism 9 are glued together, and a second PBS film 8 that transmits second polarized light and reflects first polarized light is disposed between the inclined surfaces of the second prism 5 and the third prism 9.

[0080] In the example of this application, the second prism 5 and the third prism 9 constituting the PBS prism are both right-angle prisms, and their inclined surfaces are tightly connected together by adhesive bonding. At the junction of these two inclined surfaces, a second PBS film 8 is disposed, which has the characteristics of transmitting second polarized light (P-polarized light) and reflecting first polarized light (S-polarized light).

[0081] Right-angle prisms have a relatively stable structure and are not easily affected by external environmental factors (such as temperature and vibration). By gluing the beveled surfaces of two prisms together, the stability and reliability of the structure can be enhanced. This stability is especially important for projection optical engines that need to operate for long periods of time.

[0082] The precise separation and merging effect of the second PBS film 8 can significantly improve the purity of the polarized light required in the projection optical engine. This is particularly important for applications requiring high-purity polarized light.

[0083] In summary, designing the second prism 5 and the third prism 9 as right-angle prisms and placing the second PBS film 8 on their inclined surfaces has demonstrated significant technical effects in terms of polarization separation and merging, improving optical path efficiency, enhancing optomechanical stability, simplifying optomechanical structure, optimizing optical path layout, improving polarization purity, and facilitating integration and expansion.

[0084] See some examples in this application. Figure 1 The second prism 5 includes a first right-angled surface and a second right-angled surface. The first right-angled surface is close to the first prism 2. The second phase retarder 7 is disposed on the second right-angled surface, and the second reflective element 6 is disposed on the second phase retarder 7. The third prism 9 includes a third right-angled surface and a fourth right-angled surface. The third right-angled surface is close to the fourth prism 12. The third phase retarder 10 is disposed on the fourth right-angled surface, and the third reflective element 11 is disposed on the third phase retarder 10.

[0085] See also in this application. Figure 1 The second phase retarder 7 is disposed on the second right-angled surface of the second prism 5, and the second reflective element 6 is disposed on the second phase retarder 7, similar to the second prism 5. The third phase retarder 10 and the third reflective element 11 are stacked on the fourth right-angled surface of the third prism 9. With this design, the S-polarized light (first polarized light) reflected by the second PBS film 8 will pass through the second phase retarder 7 twice. After modulation, the S-polarized light (first polarized light) is converted into P-polarized light (second polarized light). The P-polarized light (second polarized light) can transmit through the second PBS film 8, and after passing through the third phase retarder 10 twice, it is converted back into S-polarized light (first polarized light), and then reflected by the second PBS film 8 to enter the fourth prism 12.

[0086] It should be noted that integrating the phase retarder and reflective element onto the right-angled facet of the corresponding prism helps reduce the number and complexity of optical components. This simplified design not only reduces manufacturing costs and maintenance difficulty but also improves the reliability and stability of the system.

[0087] In some examples of this application, the second phase delayer 7 and the third phase delayer 10 are quarter-wave plates.

[0088] In some examples of this application, the second reflective element 6 and the third reflective element 11 are curved reflective mirrors, and the surfaces of the second reflective element 6 and the third reflective element 11 facing away from the PBS prism are curved.

[0089] Compared to planar reflections, curved reflections are better able to correct aberrations such as spherical aberration and coma. These aberrations arise from the different paths light takes as it passes through the optical system, and they cause a deterioration in image quality. By using curved mirrors, the propagation path of light can be optimized, aberrations can be reduced, and thus image sharpness and resolution can be improved.

[0090] Curved mirrors have high reflectivity, enabling them to reflect most incident light rays back to the desired direction. This high reflectivity helps improve light utilization efficiency and reduce light loss during transmission. Furthermore, the focusing or diverging capabilities of curved mirrors also help concentrate light within specific areas, further improving light utilization efficiency.

[0091] In some examples of this application, the first polarized light is S-polarized light and the second polarized light is P-polarized light.

[0092] The light propagation path of the projection optical engine provided in this embodiment is as follows:

[0093] See Figure 1Natural light from the light source module is projected onto the first PBS film 1. Since the first PBS film 1 transmits P-polarized light and reflects S-polarized light, the P-polarized light passes through and is projected onto the first phase delayer 3 after passing through the first prism 2. Because the first phase delayer 3 has a 1 / 2 phase delay effect, the P-polarized light is converted into S-polarized light and emitted from the first phase delayer 3. On the other hand, the S-polarized light separated from the natural light is reflected upwards onto the first reflective element 4. The first reflective element 4 can reflect the S-polarized light at a 90-degree angle, merging it with the S-polarized light converted from the P-polarized light to form the same S-polarized light. The light is then projected into the second prism 5, and after passing through the second PBS film 8, it undergoes a 90-degree reflection and propagates upwards. After passing through the second phase delayer 7, which has a 1 / 4 phase delay effect, the light is projected onto the surface of the second reflective element 6 after a 1 / 4 phase delay. The light is reflected back in the opposite direction and passes through the second phase delayer 7 again, where the phase is delayed by another 1 / 4. At this point, the S-polarized light has been converted into P-polarized light. The P-polarized light propagates downward, passes through the second PBS film 8, passes through the third prism 9, and after passing through the third phase delayer 10, it is projected onto the third reflective element 11. The light is also reflected back in the opposite direction and passes through the third phase delayer 10 twice, converting the P-polarized light into S-polarized light. The S-polarized light returns to the second PBS film 8, undergoes a 90-degree reflection, passes through the third prism 9, and enters the fourth prism 12. After passing through the fourth prism 12, it is projected onto the imaging chip 13. The imaging chip 13 can convert the light at a fixed position into P-polarized light according to different image information requirements. The P-polarized light enters the fourth prism 12 again and undergoes total internal reflection on the inclined surface of the fourth prism 12. The light is deflected by 90 degrees and then projected out from below, thus completing the propagation of this part of the light.

[0094] According to another embodiment of this application, an AR optical display device is also provided, the AR optical display device including a housing and a projection optical engine as described above.

[0095] The specific implementation of the AR optical display device in this application can refer to the above-described embodiments of the projection optical engine. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0096] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0097] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A projection optical engine, characterized in that, It includes a PBS prism, and a first prism (2) and a fourth prism (12) respectively disposed on opposite sides of the PBS prism, and a second reflective element (6) and a third reflective element (11) respectively disposed on opposite sides of the PBS prism; The first prism (2) has a first PBS film (1) on the light-incident side, and a first reflective element (4) is provided on the reflected light path of the first PBS film (1). A first phase delayer (3) is provided between the first prism (2) and the PBS prism. The PBS prism includes a second prism (5) and a third prism (9). A second PBS film (8) is provided between the second prism (5) and the third prism (9). A second reflective element (6) is located on one side of the second prism (5) and a second phase delayer (7) is provided between them. The second reflective element (6) is used to reflect the first polarized light reflected by the second PBS film (8). A third reflective element (11) is located on one side of the third prism (9) and a third phase delayer (10) is provided between them. The third reflective element (11) is used to reflect the second polarized light projected by the second PBS film (8).

2. The projection optical engine according to claim 1, characterized in that, The projection optical engine includes an imaging chip (13), which is disposed on the side of the fourth prism (12) away from the PBS prism. The imaging chip (13) is used to modulate the first polarized light reflected by the second PBS film (8) into second polarized light and reflect it into the fourth prism (12).

3. The projection optical engine according to claim 2, characterized in that, The fourth prism (12) is a right-angle prism. One right-angle face of the fourth prism (12) is close to the imaging chip (13), and the inclined face of the fourth prism (12) is close to the PBS prism. The inclined face of the fourth prism (12) forms a total internal reflection surface, which is used to reflect the second polarized light modulated by the imaging chip (13) to the other right-angle face of the fourth prism (12) for emission.

4. The projection optical engine according to claim 1, characterized in that, The first prism (2) is a right-angle prism, the light-incident surface of the first prism (2) is an inclined surface, the first PBS film (1) is disposed on the light-incident surface, and the first phase delayer (3) is disposed on the surface of the first prism (2) near the PBS prism.

5. The projection optical engine according to claim 1, characterized in that, The first phase delayer (3) is a half-wave plate.

6. The projection optical engine according to claim 1, characterized in that, The first reflective element (4) is a plane mirror, which is arranged parallel to the light-incident surface of the first prism (2). The first reflective element (4) is used to reflect the first polarized light reflected by the first PBS film (1) to the second PBS film (8).

7. The projection optical engine according to claim 1, characterized in that, The second prism (5) and the third prism (9) are right-angle prisms. The inclined surfaces of the second prism (5) and the third prism (9) are glued together, and a second PBS film (8) that transmits second polarized light and reflects first polarized light is provided between the inclined surface of the second prism (5) and the inclined surface of the third prism (9).

8. The projection optical engine according to claim 7, characterized in that, The second prism (5) includes a first right-angled surface and a second right-angled surface. The first right-angled surface is close to the first prism (2). The second phase retarder (7) is disposed on the second right-angled surface. The second reflective element (6) is disposed on the second phase retarder (7). The third prism (9) includes a third right-angled surface and a fourth right-angled surface. The third right-angled surface is close to the fourth prism (12). The third phase delayer (10) is disposed on the fourth right-angled surface. The third reflective element (11) is disposed on the third phase delayer (10).

9. The projection optical engine according to claim 8, characterized in that, The second phase delayer (7) and the third phase delayer (10) are quarter-wave plates.

10. The projection optical engine according to claim 1, characterized in that, The second reflective element (6) and the third reflective element (11) are curved reflective mirrors, and the surfaces of the second reflective element (6) and the third reflective element (11) facing away from the PBS prism are curved.

11. The projection optical engine according to any one of claims 1-10, characterized in that, The first polarized light is S-polarized light, and the second polarized light is P-polarized light.

12. An AR optical display device, characterized in that, include: shell; and The projection optical engine as described in any one of claims 1-11.

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