Optical module and optical display device

Abstract

Provided in the embodiments of the present application are an optical module and an optical display device. The optical module comprises a lens group arranged along the same optical axis; and a beam splitting element, a phase retarder and a polarization-selective reflective element, wherein the phase retarder is located between the beam splitting element and the polarization-selective reflective element; the lens group comprises at least two lenses; and the lens group has at least one lens with negative optical power, and the lens with negative optical power satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17, where T1 is the minimum thickness of the lens with negative optical power within a clear aperture, T2 is the maximum thickness of the lens with negative optical power within the clear aperture, and n and v are the refractive index and Abbe number of the lens with negative optical power, respectively.

Description

Optical modules and optical display devices Technical Field

[0001] This application relates to the field of optical imaging technology, and more specifically, to an optical module and an optical display device. Background Technology

[0002] With the rapid development of virtual reality technology, high definition has become a crucial trend in VR optical display devices, especially in commercial office applications where full-field-of-view clarity is paramount. However, ghosting and chromatic aberration in optical modules are key factors affecting contrast and clarity. Ghosting is typically caused by multiple reflections of light on or within the lens surface, while chromatic aberration stems from the varying refractive power of lenses for different wavelengths of light. Therefore, reducing ghosting and chromatic aberration to improve the imaging quality of optical modules is a pressing issue in the current VR technology field. Summary of the Invention

[0003] The purpose of this application is to provide a new technical solution for an optical module and an optical display device.

[0004] In a first aspect, this application provides an optical module. The optical module includes a lens group arranged along the same optical axis, a beam splitter, a phase retarder, and a polarization reflection element, wherein the phase retarder is located between the beam splitter and the polarization reflection element;

[0005] The lens group includes at least two lenses;

[0006] The lens group shall have at least one lens with negative optical power, and the lens with negative optical power shall satisfy: 3≤|(T1 / T2)*(v-50) / n|≤17; where T1 is the thinnest thickness of the lens with negative optical power within the optical effective diameter, T2 is the thickest thickness of the lens with negative optical power within the optical effective diameter, and n and v are the refractive index and Abbe number of the lens with negative optical power, respectively.

[0007] Optionally, the thickness of the lens with negative optical power in the lens group satisfies: T2 / T1≤3.

[0008] Optionally, in the lens group: the sum of the optical powers of all the negative optical power lenses is φ. m The sum of the optical powers of all lenses with positive optical power is φ. p , φ m With φ p The following condition must be met: 2≤|φ p / φ m |≤6.

[0009] Optionally, the lens group includes a first lens and a second lens;

[0010] The beam splitter is disposed on the side of the first lens away from the second lens, and the phase delayer and the polarization reflection element are disposed sequentially on the side of the second lens away from the first lens.

[0011] The first lens has a positive optical power, the second lens has a negative optical power, and the difference in Abbe number between the first lens and the second lens is Δv, where |Δv|≥14.

[0012] Optionally, the thickness of the second lens satisfies: T2 / T1≤3.

[0013] Optionally, the optical power of the first lens is φ p The optical power of the second lens is φ m ,2≤|φ p / φ m |≤6.

[0014] Optionally, the thinnest thickness T1 of the second lens within its optical effective diameter is 1.4mm≤T1≤3.45mm, and the thickest thickness T2 of the second lens within its optical effective diameter is 3.7mm≤T2≤3.8mm.

[0015] Optionally, the beam-splitting element is disposed on the surface of the first lens opposite to the second lens;

[0016] The phase delayer and the polarization reflection element are stacked on the surface of the second lens away from the first lens, and the phase delayer is located between the beam splitter and the polarization reflection element.

[0017] Optionally, the optical module further includes a polarizing element disposed on the side of the polarizing reflective element away from the phase retarder;

[0018] The polarizing element, the polarizing reflective element, and the phase delayer form a composite film.

[0019] Optionally, the optical module further includes a display screen, which is disposed along the optical axis on the side of the first lens opposite to the second lens.

[0020] Optionally, a protective glass is provided on the light-emitting surface of the display screen, and the total thickness of the protective glass is ≥0.5mm.

[0021] Secondly, this application provides an optical display device, the optical display device comprising:

[0022] The outer casing; and

[0023] The optical module as described in the first aspect.

[0024] The beneficial effects of this application are as follows:

[0025] The optical module provided in this application demonstrates significant advantages in the field of VR optical display technology. By optimizing the lens group design, particularly by finely adjusting the parameters of the negative power lens, and combining it with optical components such as beam splitters, phase delayers, and polarization reflectors, the optical module of this application successfully achieves excellent optical effects with low chromatic aberration and low ghosting. This design of this application greatly improves the clarity across the entire field of view, thereby providing users with a more delicate and realistic visual experience. Specifically, while ensuring accurate light transmission, the optical module of this application effectively reduces image blurring and distortion caused by chromatic aberration and ghosting, thus ensuring the superior performance of VR optical display devices in high-end application scenarios such as commercial offices.

[0026] 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

[0027] 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.

[0028] Figure 1 is one of the structural schematic diagrams of the optical module provided in the embodiment of this application;

[0029] Figure 2 is a schematic diagram of one of the film application methods provided in the embodiments of this application;

[0030] Figure 3 is a dot array diagram of the optical module provided in Figure 1;

[0031] Figure 4 is a modulation transfer function (MTF) curve of the optical module provided in Figure 1;

[0032] Figure 5 shows the field curvature and distortion diagram of the optical module provided in Figure 1;

[0033] Figure 6 is a transverse chromatic aberration diagram of the optical module provided in Figure 1;

[0034] Figure 7 is a second schematic diagram of the structure of the optical module provided in the embodiment of this application;

[0035] Figure 8 is a dot array diagram of the optical module provided in Figure 7;

[0036] Figure 9 shows the modulation transfer function (MTF) curve of the optical module provided in Figure 7.

[0037] Figure 10 shows the field curvature and distortion diagram of the optical module provided in Figure 7;

[0038] Figure 11 is a transverse chromatic aberration diagram of the optical module provided in Figure 7;

[0039] Figure 12 is a third schematic diagram of the structure of the optical module provided in the embodiment of this application;

[0040] Figure 13 is a dot array diagram of the optical module provided in Figure 12;

[0041] Figure 14 is a modulation transfer function (MTF) curve of the optical module provided in Figure 12;

[0042] Figure 15 shows the field curvature and distortion diagram of the optical module provided in Figure 12;

[0043] Figure 16 shows the chromatic aberration diagram of the optical module provided in Figure 12.

[0044] Explanation of reference numerals in the attached drawings: 1. Display screen; 2. Protective glass; 3. First lens; 31. First surface; 32. Second surface; 4. Second lens; 41. Third surface; 42. Fourth surface; 5. Beam splitter; 6. Phase delayer; 7. Polarizing reflector; 8. Polarizing element; 9. Anti-reflective film; 01. Human eye. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The optical module and optical display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0051] According to one embodiment of this application, an optical module is provided that is particularly suitable for near-eye optical display devices, especially virtual reality (VR) display devices, to provide an immersive visual experience. However, the application scope of this optical module is not limited to VR display devices; it can also be flexibly applied to various other types of display devices to meet different visual needs and technical requirements.

[0052] The optical module proposed in this application embodiment, as shown in Figure 1, includes a lens group arranged along the same optical axis, a beam splitter 5, a phase retarder 6, and a polarization reflection element 7, wherein the phase retarder 6 is located between the beam splitter 5 and the polarization reflection element 7; the lens group includes at least two lenses; the lens group has at least one lens with negative optical power, and the lens with negative optical power satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; where T1 is the thinnest thickness of the lens with negative optical power within the optical effective diameter, T2 is the thickest thickness of the lens with negative optical power within the optical effective diameter, and n and v are the refractive index and Abbe number of the lens with negative optical power, respectively.

[0053] The optical module provided in this application embodiment, as shown in Figures 1, 7, and 12, includes optical components such as a lens group, a beam splitter 5, a phase delayer 6, and a polarization reflection element 7. These optical components are described below.

[0054] The lens group is one of the core components of the optical module of this application, responsible for focusing light, imaging, and correcting aberrations. In this application, the lens group includes at least two lenses, and at least one of them is a negative power lens. The introduction of a negative power lens helps correct chromatic aberration in the optical module, thereby improving image quality.

[0055] While increasing the number of lenses can improve the imaging quality and correction capabilities of an optical module to some extent, an excessive number of lenses can also lead to a series of drawbacks, such as increased cost, increased structural complexity, and increased size and weight. Therefore, when designing an optical module, it is necessary to weigh the relationship between the number of lenses and module performance, cost, and complexity to select the optimal lens configuration.

[0056] The optical module provided in this application embodiment may employ 2 to 4 lenses in the lens group.

[0057] In addition to the lens group, the optical module provided in this application embodiment also includes multiple optical films, such as beam splitter 5, phase delayer 6 and polarization reflection element 7.

[0058] The beam-splitting element 5 is, for example, a thin film or coating with specific beam-splitting characteristics, which can be used to reflect and transmit incident light in a certain proportion. Specifically, the beam-splitting element 5 can be a semi-transparent and semi-reflective film, which allows a portion of the light to be transmitted and another portion to be reflected.

[0059] It should be noted that the reflectivity and transmittance of the beam splitter 5 can be flexibly adjusted according to specific needs, and this embodiment does not impose any restrictions on this.

[0060] The phase retarder 6 can be used to change the polarization state of light, such as converting linearly polarized light into circularly polarized light, or vice versa. In this application, the phase retarder 6 is, for example, a quarter-wave plate, located between the beam splitter 5 and the polarizing reflector 7, which adjusts the phase of the light to ensure that the light is correctly reflected or transmitted in its subsequent path.

[0061] The polarization reflecting element 7 is a polarization reflector that reflects horizontally linearly polarized light and transmits vertically linearly polarized light, or any other polarization reflector that reflects linearly polarized light at a specific angle and transmits linearly polarized light perpendicular to that angle. In other words, the polarization reflecting element 7 is responsible for reflecting or transmitting light according to its polarization state. In the optical module provided in this application embodiment, it interacts with a specific state of polarized light (such as S-light or P-light) to achieve specific path control of the light.

[0062] In the optical module of the embodiments of this application, the lens group must include at least one lens with negative optical power, and the Abbe number of the negative optical power lens is specifically set to be significantly different from the Abbe number of the positive optical power lens. This design aims to correct chromatic aberration generated in the optical module, thereby significantly improving image quality.

[0063] Furthermore, the design of a negative power lens allows for a more uniform distribution of light as it passes through the lens group, effectively reducing the size of the light spot on the image plane. This improvement not only further enhances image sharpness but also significantly improves image contrast, providing users with a superior visual experience.

[0064] It should be noted that the Abbe number of a lens, also known as the dispersion coefficient, reflects the lens's ability to disperse light of different wavelengths.

[0065] In the embodiments of this application, the parameter relationship is designed as 3≤|(T1 / T2)*(v-50) / n|≤17. This parameter relationship allows for reasonable control of the thickness ratio (T1 / T2), refractive index (n), and Abbe number (v) of the negative optical power lens. This parameter range design ensures that the refractive power of the negative optical power lens is reasonably matched under different wavelengths of light, thereby effectively reducing chromatic aberration. Chromatic aberration is one of the important factors affecting image quality. Through the design of this application, image blurring and color distortion caused by chromatic aberration can be significantly reduced.

[0066] Furthermore, "ghosting" is an interfering image caused by multiple reflections and refractions of light on the surface of optical elements (such as lenses). The optical module provided in this application reduces unnecessary reflections and refractions of light on or inside the lens surface by rationally arranging and designing the parameters of the lens group, thereby reducing the generation of "ghosting". In particular, the parameter control of the negative power lens makes the propagation path of light within the lens more reasonable, reduces the influence of stray light, and further improves the image quality.

[0067] In this application, the lower limit of |(T1 / T2)*(v-50) / n| is 3, which avoids the instability of the optical performance of the entire optical module caused by extreme cases (such as when the values ​​of T1 / T2, v-50 or n are too small).

[0068] Specifically, when the lower limit is set to 3, it means that when designing a lens with negative optical power, it is necessary to ensure that the combination of the lens's thickness ratio (T1 / T2), refractive index (n), and Abbe number (v) meets certain conditions in order to guarantee the chromatic aberration and ghosting correction capabilities of the optical module.

[0069] The upper limit of |(T1 / T2)*(v-50) / n| is 17. This upper limit of 17 restricts the maximum value of the parameter to prevent the performance of the optical module from degrading or the manufacturing difficulty from increasing due to excessively large parameters.

[0070] Specifically, when the upper limit is set to 17, it means that when designing a lens with negative optical power, it is necessary to balance the lens's thickness ratio, refractive index, and Abbe number to avoid additional aberrations or manufacturing difficulties caused by excessively large parameters.

[0071] When |(T1 / T2)*(v-50) / n| < 3, it may negatively impact chromatic aberration correction capability. If the parameter is below the lower limit of 3, it may mean that the combination of the thickness ratio, refractive index, and Abbe number of a lens with negative optical power cannot effectively correct chromatic aberration, leading to a decrease in image quality. Furthermore, low parameter values ​​may cause ghosting to become more pronounced, affecting image sharpness and contrast. In addition, excessively thin lenses or extreme combinations of refractive index / Abbe number may increase manufacturing difficulty and cost.

[0072] When |(T1 / T2)*(v-50) / n|>17, it may introduce additional aberrations, such as spherical aberration and coma, thus affecting image quality. Lens materials with high refractive index or special Abbe numbers may be more expensive, leading to increased costs.

[0073] The optical module provided in this application demonstrates significant advantages in the field of VR optical display technology. By optimizing the lens group design, particularly by finely adjusting the parameters of the negative power lens, and combining it with optical components such as the beam splitter 5, phase delayer 6, and polarization reflector 7, the optical module of this application successfully achieves excellent optical effects with low chromatic aberration and low ghosting. This design of this application greatly improves the clarity across the entire field of view, thereby providing users with a more delicate and realistic visual experience. Specifically, while ensuring accurate light transmission, the optical module of this application effectively reduces image blurring and distortion caused by chromatic aberration and ghosting, thus ensuring the superior performance of VR optical display devices in high-end application scenarios such as commercial offices.

[0074] In some examples of this application, the thickness of the lens with negative optical power in the lens group satisfies: T2 / T1≤3.

[0075] In this example of the application, a specific thickness relationship is set for the negative power lens in the lens group, namely T2 / T1≤3. This design aims to optimize the optical performance of the optical module, especially to reduce the "ghosting" phenomenon.

[0076] Where T2 represents the maximum thickness of the lens with negative optical power within its effective optical diameter. T1 represents the minimum thickness of the lens with negative optical power within its effective optical diameter. By setting T2 / T1≤3, the range of thickness variation of the lens with negative optical power is limited, ensuring that the thickness distribution of the lens is relatively uniform.

[0077] If a negative power lens is made of plastic, its thickness ratio (T2 / T1) will significantly affect the stress distribution of the lens. Stress is an internal force generated within the lens due to material inhomogeneity, temperature changes, or external forces, which can lead to lens deformation or optical distortion.

[0078] Specifically, the greater the thickness difference between the thicker portion (T2) and the thinner portion (T1) of a negative power lens, the more uneven the stress inside the lens. By setting T2 / T1 ≤ 3, this thickness difference can be limited, thereby reducing the stress level inside the lens. Reduced stress helps decrease reflections and scattering within the lens, thus reducing the occurrence of "ghosting" phenomena.

[0079] In this example of the application, by constraining the ratio of T2 / T1, the stress generated in the lens during the manufacturing process due to material inhomogeneity or temperature changes can be effectively reduced. This stress reduction helps maintain the shape stability of the lens and minimizes lens deformation caused by stress.

[0080] It's important to note that "ghosting" is a stray light phenomenon caused by multiple reflections of light within a lens, which affects image sharpness and contrast. Stress exacerbates reflection and scattering within the lens, thus increasing ghosting. Therefore, reducing stress can reduce ghosting and improve image sharpness and contrast.

[0081] The stable lens shape and reduced ghosting phenomena together improve the optical performance of the lens group in this application. This enables the optical module of this application to transmit image information more accurately, meeting the needs of high-definition VR applications.

[0082] The thickness ratio (T2 / T1≤3) set for the negative power lens in this application aims to reduce the stress level during lens manufacturing, thereby reducing ghosting and improving the optical performance of the optical module. This design provides strong technical support for high-definition VR applications.

[0083] In some examples of this application, in the lens group: the sum of the optical powers of all the negative optical power lenses is φ. m The sum of the optical powers of all lenses with positive optical power is φ. p , φ m With φ p The following condition must be met: 2≤|φ p / φ m |≤6.

[0084] This application proposes a matching principle, namely, the sum of the optical powers of all lenses with negative optical powers is φ. m The sum of the optical powers of all lenses with positive optical power is φ. p And the two satisfy 2≤|φ p / φ m |≤6. This matching principle aims to optimize light transmission through a reasonable combination of positive and negative optical power, thereby eliminating chromatic aberration.

[0085] It should be noted that chromatic aberration occurs because lenses have different refractive indices for different wavelengths of light. When light passes through a lens, different wavelengths of light are refracted to different degrees due to their different refractive indices, resulting in different focal points on the image plane during imaging, which is chromatic aberration.

[0086] By appropriately combining lenses with positive and negative optical powers, this application enables light of different wavelengths to be better focused on the same point after passing through the lens group of this application, thereby eliminating chromatic aberration.

[0087] Specifically, the combination of positive and negative lenses allows for better control of light transmission. A positive lens enhances the converging ability of light, while a negative lens weakens the converging ability or causes the light to diverge. By appropriately combining these two types of lenses, light rays can be better kept parallel or focused on a single point after passing through the lens group.

[0088] In this application, lenses with positive and negative optical powers are appropriately matched, and the condition 2≤|φ is met. p / φ m The pairing principle of |≤6 can achieve the effect of low color difference and low ghosting, thereby improving the clarity and contrast of the optical module.

[0089] In some examples of this application, referring to Figures 1, 7 and 12, the lens group includes a first lens 3 and a second lens 4; the beam splitter 5 is disposed on the side of the first lens 3 away from the second lens 4, and the phase retarder 6 and the polarization reflection element 7 are sequentially disposed on the side of the second lens 4 away from the first lens 3; the optical power of the first lens 3 is positive, the optical power of the second lens 4 is negative, and the difference in Abbe number between the first lens 3 and the second lens 4 is Δv, where |Δv|≥14.

[0090] In this example of the application, the lens group includes a first lens 3 and a second lens 4 arranged adjacent to each other along the optical axis. The first lens 3 has a positive optical power, while the second lens 4 has a negative optical power. This combination of positive and negative optical power helps to optimize the light transmission path and improve image quality.

[0091] In this example of the application, the beam splitter 5, the phase retarder 6, and the polarization reflector 7 are respectively disposed on both sides of the lens group, and can form a folded optical path when combined with the lens group. This can improve image quality while reducing the size of the optical module.

[0092] The Abbe number is an important indicator of the dispersive ability of a lens material, reflecting the difference in refractive index of the lens for different wavelengths of light. The higher the Abbe number, the smaller the dispersion of the lens, and the better the image quality.

[0093] In this example of the application, the Abbe number difference between the first lens 3 (a lens with positive optical power) and the second lens 4 (a lens with negative optical power) is Δv, and |Δv|≥14. This combination of positive and negative optical power, coupled with the large Abbe number difference, helps to introduce different dispersion characteristics into the lens group, thereby achieving chromatic aberration correction.

[0094] Specifically, referring to Figure 1, the second lens 4 on the side closer to the human eye 01 is a lens with negative optical power, and it has a significant difference in Abbe number from the first lens 3 (a lens with positive optical power) on the side closer to the screen, which helps to achieve chromatic aberration correction.

[0095] By appropriately combining lenses with different Abbe numbers, light of different wavelengths can be better focused onto the same point after passing through the lens group of this application, thereby eliminating or reducing chromatic aberration. In this application, the first lens 3 and the second lens 4 have a large difference in Abbe number. This difference helps to introduce mutually canceling dispersion effects into the lens group, thereby achieving the correction of chromatic aberration.

[0096] This application utilizes a reasonable combination of lenses with positive and negative optical powers and introduces a significant Abbe number difference to effectively correct chromatic aberration and improve image quality. This is particularly important for VR optical display devices, as high definition is one of the key elements for VR development.

[0097] It should be noted that the lens group can also incorporate 1 to 2 more lenses. The newly added lenses can be placed on the side closer to the human eye 01 or on the side closer to the display screen 1. This application does not impose any restrictions on this, and the specific arrangement can be flexibly adjusted as needed.

[0098] In some examples of this application, the thickness of the second lens 4 satisfies: T2 / T1≤3.

[0099] In this application, referring to Figures 1, 7, and 12, the second lens 4 is a negative power lens in the lens group, with a thickness ratio satisfying T2 / T1≤3. This design aims to reduce the stress level during the production of the second lens 4, thereby reducing ghosting and improving the optical performance of the optical module. This design provides strong technical support for high-definition VR applications.

[0100] It should be noted that the second lens 4 is a negative power lens, as shown in Figures 1, 7, and 12, and it is located on the side closest to the human eye 01. In fact, when an additional lens is added to the lens group, the negative power lens can also be located in the middle position.

[0101] In some examples of this application, referring to Figures 1, 7 and 12, the optical power of the first lens 3 is φ. p The optical power of the second lens 4 is φ m ,2≤|φ p / φ m |≤6.

[0102] In this example of the application, a specific matching principle is proposed, namely, the optical power of the second lens 4 with negative optical power is φ. mThe optical power of the first lens 3 with positive optical power is φ p And the two satisfy 2≤|φ p / φ m |≤6. This combination aims to optimize light transmission through a proper balance of positive and negative optical power, thereby eliminating chromatic aberration.

[0103] In some examples of this application, the thinnest thickness T1 of the second lens 4 within the optical effective diameter is 1.4 mm ≤ T1 ≤ 3.45 mm, and the thickest thickness T2 of the second lens 4 within the optical effective diameter is 3.7 mm ≤ T2 ≤ 3.8 mm.

[0104] For T1 and T2 within a given range, the ratio of T2 / T1 is always less than or equal to 3.

[0105] A thinner lens portion (T1) and an appropriate thickness ratio (T2 / T1≤3) help reduce stress buildup during manufacturing. During lens production, stress can cause birefringence or other optical defects, affecting image quality. By controlling the lens's thickness ratio, these stresses can be reduced, thereby improving the lens's optical performance and reliability.

[0106] In optical modules, weight reduction plays a positive role in improving wearing comfort. In this example, by rationally designing the lens thickness, the overall weight of the module can be reduced as much as possible while ensuring optical performance.

[0107] In some examples of this application, referring to Figures 1, 7 and 12, the beam splitter 5 is disposed on the surface of the first lens 3 facing away from the second lens 4; the phase delayer 6 and the polarization reflection element 7 are stacked on the surface of the second lens 4 facing away from the first lens 3, and the phase delayer 6 is located between the beam splitter 5 and the polarization reflection element 7.

[0108] In the optical module provided in this application, the first lens 3 is located on the side near the screen, and it includes two surfaces: a first surface 31 and a second surface 32. Referring to Figure 1, the beam splitting element 5 is directly disposed on the first surface 31.

[0109] In the optical module provided in this application, the second lens 4 is located on the side closest to the human eye 01, and it includes two surfaces: a third surface 41 and a fourth surface 42. Referring to Figure 1, the phase retarder 6 and the polarization reflection element 7 are stacked on the fourth surface 42.

[0110] By directly mounting the beam splitter 5, the phase retarder 6, and the polarization reflector 7 on the surfaces of different lenses, the integration of the optical module is greatly improved. This tightly integrated structure not only reduces the gaps between components but also simplifies the overall architecture of the optical module, making the entire optical module more compact and lightweight.

[0111] The close integration of the beam-splitting element 5 with the lens surface helps reduce aberrations and distortions caused by excessively long optical paths or improper refraction angles. This design ensures that the light maintains high imaging quality after beam splitting, providing users with a clearer and more realistic visual experience.

[0112] In some examples of this application, referring to Figures 1, 7 and 12, the optical module further includes a polarizing element 8, which is disposed on the side of the polarizing reflective element 7 away from the phase retarder 6; the polarizing element 8, the polarizing reflective element 7 and the phase retarder 6 form a composite film.

[0113] Wherein, the polarizing element 8 is a polarizing film, which can selectively transmit or reflect light vibrations in a specific direction.

[0114] In the optical module of this application, by introducing a polarizing element 8 and placing it on the side of the polarizing reflective element 7 away from the phase delayer 6, this design can reduce stray light interference.

[0115] Specifically, stray light is typically unwanted light generated by reflection, scattering, or refraction of light at an interface. By positioning the polarizing element 8 on the side of the polarizing reflective element 7 away from the phase retarder 6, stray light that is not aligned with the direction of the main ray can be filtered out, reducing its interference with image quality. This helps improve image contrast and sharpness, making the viewing of virtual images more realistic and immersive for users.

[0116] The reduction of stray light directly improves image quality. In virtual reality applications, high-contrast and sharp images are fundamental to providing a high-quality visual experience. The introduction of the polarizing element 8 allows the system to better control the direction and state of light propagation, reducing unnecessary light interference and thus improving the overall image presentation.

[0117] In addition to directly improving image quality, the introduction of the polarizing element 8 also helps to improve the overall efficiency of the optical module. By reducing stray light propagation and energy loss, the optical module can utilize light energy more efficiently, concentrating more energy in the imaging process.

[0118] In this example of the application, referring to FIG2, the polarizing element 8, the polarizing reflective element 7 and the phase delayer 6 are stacked to form a composite film.

[0119] By stacking multiple optical elements together to form a highly integrated composite film, the structure of the optical module is simplified, and its size is significantly reduced. This integrated design helps to achieve thinner and lighter virtual reality devices, improving user comfort and portability.

[0120] The close arrangement of components in the composite film helps optimize the light propagation path and reduce energy loss and aberrations during light transmission between components. In particular, the close cooperation between the phase retarder 6, the polarizing element 8, and the polarizing reflection element 7 allows for more precise control of the polarization state and reflection direction of the light, thereby improving image quality.

[0121] Traditional optical modules require the individual installation and adjustment of each component, while the design of composite film materials simplifies the assembly process. The composite film material can be installed into the system as a whole unit, thereby improving production efficiency.

[0122] Optionally, referring to Figure 2, an anti-reflective film 9 can also be introduced into the composite film material. The anti-reflective film 9 can reduce the reflection of light on the lens surface, thereby increasing the light transmittance. This not only improves the brightness of the image but also improves the overall optical performance of the optical module.

[0123] In some examples of this application, referring to Figures 1, 7 and 12, the optical module further includes a display screen 1, which is disposed along the optical axis on the side of the first lens 3 opposite to the second lens 4.

[0124] The display screen 1 is used to emit imaging light.

[0125] Optionally, the optical module of this application further includes a stacking element, which comprises two phase retardation films and a polarizing film disposed between the two phase retardation films. The stacking element is disposed on the light-emitting surface of the display screen 1. The two phase retardation films are quarter-wave plates.

[0126] In this example of the application, the combination of a phase retardation film (as a quarter-wave plate) and a polarizing film in the composite element effectively eliminates stray light reflected from the display screen 1 itself. When imaging light is emitted from the display screen 1, it is converted into linearly polarized light in a specific direction by a phase retardation film. Subsequently, the polarizing film only allows linearly polarized light in that specific direction to pass through, while blocking linearly polarized light in other directions (including stray light reflected from the screen). Finally, another phase retardation film converts the linearly polarized light back into circularly polarized light for subsequent optical processing. This process significantly reduces the interference of reflections from the display screen 1 on image quality, improving image sharpness and contrast.

[0127] By adjusting the superimposed elements, light loss during transmission is reduced, thereby improving light utilization. This helps to enhance image brightness.

[0128] The superimposed elements also help enhance the color performance of the image. By optimizing the polarization state and phase of light, dispersion and chromatic aberration during transmission can be reduced, resulting in more vibrant and accurate colors in the image. This is of great significance for improving the realism and immersion of the virtual reality experience.

[0129] Optionally, an antireflection coating can be introduced into the composite element. The main function of the antireflection coating is to reduce light reflection loss at the interface, thereby increasing light transmittance. In an optical module, each reflection of light results in some energy loss, reducing the overall efficiency of the optical module. By reducing light reflection loss, the energy distribution inside the optical module is more uniform, which is beneficial for improving the uniformity and consistency of imaging.

[0130] In some examples of this application, referring to Figure 1, a protective glass 2 is provided on the light-emitting surface of the display screen 1, and the total thickness of the protective glass 2 is ≥0.5mm.

[0131] According to this example of the application, the design effectively improves the optical scheme's tolerance to dirt on the surface of the display screen 1, reducing the risk of image quality being affected by screen contamination.

[0132] Specifically, the protective glass 2 in front of the display screen 1 effectively isolates external dust, fingerprints, and other contaminants, thereby keeping the surface of the display screen 1 clean. This is crucial for the optical module, as any dirt on the screen surface can affect light transmission and image quality. By introducing a protective glass 2 with a certain thickness, the tolerance of the optical module to dirt on the surface of the display screen 1 is significantly improved, ensuring the stability and reliability of the optical module.

[0133] The protective glass 2 not only isolates dirt and grime but also effectively prevents the display screen 1 from being scratched, bumped, or otherwise physically damaged. This is of great significance for extending the service life of the display screen 1 and improving the overall durability of the device.

[0134] The optical module provided in this application embodiment propagates light as follows, as shown in Figure 1:

[0135] The display screen 1 emits circularly polarized light, which is transmitted through the protective glass 2 and the first lens 3, and becomes linearly polarized light (S light) after passing through the phase retarder 6 (such as a quarter-wave plate) on the fourth surface 42 of the second lens 4. After being reflected by the polarization reflection element 7, it becomes circularly polarized light again after passing through the phase retarder 6, and is reflected by the beam splitter 5 on the first surface 31 of the first lens 3, and becomes linearly polarized light (P light) after passing through the phase retarder 6 for the third time. After passing through the polarizing element 8 and the anti-reflection film 9, it enters the human eye 01 for imaging.

[0136] For the optical module provided in the embodiment of the present application, as shown in FIGS. 1, 7 and 12, the materials of the lenses (such as the first lens 3 and the second lens 4) included therein have a refractive index and a dispersion coefficient range of: 1.4 < n < 2.0, 20 < v < 75. This helps to reduce chromatic aberration and other aberrations, and improve the stability and imaging quality of the optical module.

[0137] Taking the optical module shown in FIG. 1 as an example, the first lens 3 and the second lens 4 therein are described as follows.

[0138] The central thickness range of the first lens 3 is, for example: 1 mm ≤ T ≤ 8 mm, and it includes two optical surfaces, namely the first surface 31 and the second surface 32. These two optical surfaces are aspherical or planar. Among them, the beam splitter 5 is provided on the first surface 31, and an anti-reflection film layer may be provided on the second surface 32.

[0139] The central thickness range of the second lens 4 is: 1 mm ≤ T ≤ 10 mm, and it includes two optical surfaces, namely the third surface 41 and the fourth surface 42. These two surfaces are aspherical or planar. The fourth surface 42 is provided with a film layer structure, as shown in FIG. 2, including an anti-reflection film 9, a phase retarder 6 (quarter-wave plate), a polarization reflection element 7 (transmits P light and reflects S light), and a polarizing element 8 (transmits P light). An anti-reflection film layer is provided on the third surface 41.

[0140] The optical module provided by the present application is further described below through Examples 1 to 3.

[0141] Example 1

[0142] Referring to FIG. 1, the optical module provided in this Example 1 includes a lens group arranged along the same optical axis, as well as a beam splitter 5, a phase retarder 6 and a polarization reflection element 7, and the phase retarder 6 is located between the beam splitter 5 and the polarization reflection element 7;

[0143] The lens group includes a first lens 3 and a second lens 4. The beam splitter 5 is disposed on the surface of the first lens 3 away from the second lens 4. The phase delayer 6 and the polarization reflection element 7 are stacked on the surface of the second lens 4 away from the first lens 3.

[0144] The optical power of the first lens 3 is positive, the optical power of the second lens 4 is negative, and the difference in Abbe number between the first lens 3 and the second lens 4 is Δv, where |Δv|≥14;

[0145] The thickness of the second lens 4 satisfies: T2 / T1≤3;

[0146] The optical power of the first lens 3 is φ p The optical power of the second lens 4 is φ m ,2≤|φ p / φ m |≤6;

[0147] The second lens 4 satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; where T1 is the thinnest thickness of the second lens within the optical effective diameter, T2 is the thickest thickness of the second lens 4 within the optical effective diameter, and n and v are the refractive index and Abbe number of the second lens 4, respectively.

[0148] The optical module also includes a polarizing element 8, which is disposed on the side of the polarizing reflective element 7 away from the phase retarder 6. The polarizing element 8, the polarizing reflective element 7, and the phase retarder 6 form a composite film, as shown in Figure 2.

[0149] The optical module also includes a display screen 1, which is disposed along the optical axis on the side of the first lens 3 away from the second lens 4. A protective glass 2 is disposed on the light-emitting surface of the display screen, and the total thickness of the protective glass 2 is ≥0.5mm.

[0150] Table 1 shows the specific optical parameters of the optical module in this embodiment 1.

[0151] Table 1

[0152] In addition, Table 4 following Example 3 shows other parameters involved in Example 1.

[0153] The optical module provided in this embodiment 1 has the optical performance shown in Figures 3 and 6: Figure 3 is a dot plot diagram, Figure 4 is an MTF curve diagram, Figure 5 is a field curvature distortion diagram, and Figure 6 is a lateral chromatic aberration diagram.

[0154] A dot plot refers to a diffuse pattern formed by numerous rays emanating from a single point. Due to aberrations, these rays intersect the image plane at a point no longer, creating a scattered pattern over a certain range. This pattern is used to evaluate the imaging quality of the projection optical module. Referring to Figure 3, in the optical module provided in Embodiment 1, the maximum value of the image points in the dot plot is less than 7 μm.

[0155] The MTF curve is a modulation transfer function graph, which characterizes the imaging sharpness of the optical module through the contrast of black and white line pairs. Referring to Figure 4, the optical module provided in this embodiment 1 has an MTF > 0.3 at 35 lp / mm.

[0156] Referring to Figure 5, the optical module provided in this embodiment 1 has the maximum distortion occurring in the field of view, with an absolute value of less than 35%.

[0157] Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions between blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. Referring to Figure 6, the optical module provided in Example 1 has a maximum chromatic aberration value of less than 65 μm.

[0158] Example 2

[0159] Referring to Figure 7, the optical architecture of this embodiment 2 is the same as that of embodiment 1 described above. The differences are shown in Table 2 below and Table 4 shown after embodiment 3.

[0160] Table 2 shows the specific optical parameters of the optical module in this embodiment 2.

[0161] Table 2

[0162] The optical module provided in this embodiment 2 has the optical performance shown in Figures 8 and 11: Figure 8 is a dot plot diagram, Figure 9 is an MTF curve diagram, Figure 10 is a field curvature distortion diagram, and Figure 11 is a lateral chromatic aberration diagram.

[0163] Referring to Figure 8, the maximum value of the image point in the dot matrix diagram of the optical module provided in this embodiment 2 is less than 10 μm.

[0164] Referring to Figure 9, the optical module provided in this embodiment 2 has an MTF > 0.3 at 35 lp / mm.

[0165] Referring to Figure 10, the optical module provided in this embodiment 2 has the largest distortion occurring in the field of view, with an absolute value of less than 35%, which is very small.

[0166] Referring to Figure 11, the optical module provided in this embodiment 2 has a maximum color difference value of less than 65μm.

[0167] Example 3

[0168] Referring to Figure 12, the optical architecture of this embodiment 3 is the same as that of embodiment 1 described above. The differences are shown in Table 3 below and Table 4 shown after embodiment 3.

[0169] Table 3 shows the specific optical parameters of the optical module in this embodiment 3.

[0170] Table 3

[0171] The optical module provided in this embodiment 3 has the optical performance shown in Figures 13 and 16: Figure 13 is a dot plot diagram, Figure 14 is an MTF curve diagram, Figure 15 is a field curvature distortion diagram, and Figure 16 is a lateral chromatic aberration diagram.

[0172] Referring to Figure 13, the maximum value of the image point in the dot matrix diagram of the optical module provided in this embodiment 3 is less than 33μm.

[0173] Referring to Figure 14, the optical module provided in this embodiment 3 has an MTF > 0.3 at 35 lp / mm.

[0174] Referring to Figure 15, the optical module provided in this embodiment 3 has the largest distortion occurring in the field of view, with an absolute value of less than 35%, which is very small.

[0175] Referring to Figure 16, the optical module provided in this embodiment 3 has a maximum color difference value of less than 65μm.

[0176] Table 4 Parameters in Examples 1 to 3

[0177] According to another embodiment of this application, an optical display device is provided, which includes: a housing and an optical module as described above.

[0178] The optical display device provided in the embodiments of this application is, for example, a VR display device.

[0179] The specific implementation of the optical display device in this application can refer to the above-described embodiments of the optical module. 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.

[0180] 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.

[0181] 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. An optical module, characterized in that, It includes a lens group arranged along the same optical axis, as well as a beam splitter (5), a phase retarder (6) and a polarization reflection element (7), wherein the phase retarder (6) is located between the beam splitter (5) and the polarization reflection element (7); The lens group includes at least two lenses; The lens group shall have at least one lens with negative optical power, and the lens with negative optical power shall satisfy: 3≤|(T1 / T2)*(v-50) / n|≤17; where T1 is the thinnest thickness of the lens with negative optical power within the optical effective diameter, T2 is the thickest thickness of the lens with negative optical power within the optical effective diameter, and n and v are the refractive index and Abbe number of the lens with negative optical power, respectively.

2. The optical module according to claim 1, characterized in that, The thickness of the negative optical power lens in the lens group satisfies: T2 / T1≤3.

3. The optical module according to claim 2, characterized in that, In the lens group: the sum of the optical powers of all the negative optical power lenses is φ. m The sum of the optical powers of all lenses with positive optical power is φ. p φ m With φ p The following condition must be met: 2≤|φ p / φ m |≤6.

4. The optical module according to any one of claims 1-3, characterized in that, The lens group includes a first lens (3) and a second lens (4); The beam splitter (5) is disposed on the side of the first lens (3) away from the second lens (4), and the phase delayer (6) and the polarization reflection element (7) are disposed sequentially on the side of the second lens (4) away from the first lens (3). The optical power of the first lens (3) is positive, the optical power of the second lens (4) is negative, and the difference in Abbe number between the first lens (3) and the second lens (4) is Δv, |Δv|≥14.

5. The optical module according to claim 4, characterized in that, The thickness of the second lens (4) satisfies: T2 / T1≤3.

6. The optical module according to claim 4, characterized in that, The optical power of the first lens (3) is φ p The optical power of the second lens (4) is φ m ,2≤|φ p / φ m |≤6.

7. The optical module according to claim 5, characterized in that, The thinnest thickness T1 of the second lens (4) within the optical effective diameter is 1.4mm≤T1≤3.45mm, and the thickest thickness T2 of the second lens (4) within the optical effective diameter is 3.7mm≤T2≤3.8mm.

8. The optical module according to claim 4, characterized in that, The beam splitting element (5) is disposed on the surface of the first lens (3) away from the second lens (4); The phase delayer (6) and the polarization reflection element (7) are stacked on the surface of the second lens (4) away from the first lens (3), and the phase delayer (6) is located between the beam splitter (5) and the polarization reflection element (7).

9. The optical module according to claim 8, characterized in that, The optical module also includes a polarizing element (8), which is disposed on the side of the polarizing reflective element (7) away from the phase retarder (6); The polarizing element (8), the polarizing reflection element (7), and the phase delayer (6) form a composite film.

10. The optical module according to claim 4, characterized in that, The optical module also includes a display screen (1), which is disposed along the optical axis on the side of the first lens (3) away from the second lens (4).

11. The optical module according to claim 10, characterized in that, The display screen (1) has a protective glass (2) on its light-emitting surface, and the total thickness of the protective glass (2) is ≥0.5mm.

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

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