Optical module and optical display device

Abstract

The embodiment of the invention provides an optical module and optical display equipment. Wherein the optical module comprises a lens group, a light splitting element, a phase retarder and a polarization reflection element which are arranged along the same optical axis, and the phase retarder is located between the light splitting element and the polarization reflection element; the lens group at least comprises two lenses; the lens group is provided with at least one lens with negative focal power, and the lens with the negative focal power meets the condition that (T1 / T2) * (v-50) / n is more than or equal to 3 and less than or equal to 17; wherein T1 is the thinnest thickness of the lens with the negative focal power in the optical effective diameter, T2 is the maximum thickness of the lens with the negative focal power in the optical effective diameter, and n and v are the refractive index and the Abbe number of the lens with the negative focal power respectively.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical imaging technology, and more specifically, the embodiments of the present application relate to an optical module and an optical display device. Background Art

[0002] With the rapid development of virtual reality technology, high definition has become an important development trend of VR optical display devices, especially in commercial office and other application scenarios, where clarity in the full field of view is crucial. However, ghosting and chromatic aberration in optical modules are key factors affecting contrast and clarity. Ghosting is usually caused by multiple reflections of light on the surface or inside the lens, while chromatic aberration comes from the different refraction capabilities of the lens for light of different wavelengths. Therefore, how to reduce ghosting and chromatic aberration and improve the imaging quality of optical modules is an urgent problem to be solved in the current field of VR technology. 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, the present 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 comprises at least one lens with negative optical power, and the lens with negative optical power satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; wherein T1 is the thinnest thickness of the lens with negative optical power within the optically effective diameter, T2 is the thickest thickness of the lens with negative optical power within the optically 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 focal length in the lens group satisfies: T2 / T1≤3.

[0008] Optionally, in the lens group: the sum of the focal powers of all lenses with negative focal powers is φ m , the sum of the focal powers of all positive lenses is φ p ,φ m With φ p Satisfy between: 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 a side of the first lens away from the second lens, and the phase retarder and the polarization reflection element are sequentially disposed on a side of the second lens away from the first lens;

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

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

[0013] Optionally, the focal length of the first lens is φ p , the focal 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 the optically effective diameter is 1.4 mm≤T1≤3.45 mm, and the thickest thickness T2 of the second lens within the optically effective diameter is 3.7 mm≤T2≤3.8 mm.

[0015] Optionally, the beam splitter element is disposed on a surface of the first lens facing away from the second lens;

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

[0017] Optionally, the optical module further comprises a polarizing element, and the polarizing element is arranged on a side of the polarizing reflective element away from the phase retarder;

[0018] The polarizing element, the polarizing reflecting element and the phase retarder form a composite film material.

[0019] Optionally, the optical module further includes a display screen, and the display screen is arranged along the optical axis on a side of the first lens away from 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 ≥0.5 mm.

[0021] In a second aspect, the present application provides an optical display device, the optical display device comprising:

[0022] casing; and

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

[0024] The beneficial effects of this application are:

[0025] The optical module provided in the embodiment of the present application shows significant advantages in the field of VR optical display technology. By optimizing the design of the lens group, especially finely adjusting the parameters of the negative focal length lens, and matching optical components such as the beam splitter, phase retarder and polarized reflective element, the optical module of the present application successfully achieves excellent optical effects of low chromatic aberration and low ghosting. This design of the present application greatly improves the clarity under the full field of view, thereby providing users with a more delicate and realistic visual experience. Specifically, the optical module of the present application effectively reduces the image blur and distortion caused by chromatic aberration and ghosting while ensuring the precise transmission of light, thereby ensuring the excellent performance of VR optical display equipment in high-end application scenarios such as commercial office.

[0026] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0028] Figure 1 One of the structural schematic diagrams of the optical module provided in the embodiment of the present application;

[0029] Figure 2 This is one of the schematic diagrams of the film application method provided in the embodiment of the present application;

[0030] Figure 3 for Figure 1 A dot array diagram of the provided optical module;

[0031] Figure 4 for Figure 1 The modulation transfer function (MTF) curve of the optical module provided;

[0032] Figure 5 for Figure 1 Field curvature and distortion diagrams of the provided optical modules;

[0033] Figure 6 for Figure 1 Vertical axis chromatic aberration diagram of the provided optical module;

[0034] Figure 7 The second structural schematic diagram of the optical module provided in the embodiment of the present application;

[0035] Figure 8 for Figure 7 A dot array diagram of the provided optical module;

[0036] Fig. 9 for Figure 7 The modulation transfer function (MTF) curve of the optical module provided;

[0037] Fig.10 for Figure 7 Field curvature and distortion diagrams of the provided optical modules;

[0038] Fig.11 for Figure 7 Vertical axis chromatic aberration diagram of the provided optical module;

[0039] Fig.12 The third structural diagram of the optical module provided in the embodiment of the present application;

[0040] Fig.13 for Fig.12 A dot array diagram of the provided optical module;

[0041] Fig.14 for Fig.12 The modulation transfer function (MTF) curve of the optical module provided;

[0042] Fig.15 for Fig.12 Field curvature and distortion diagrams of the provided optical modules;

[0043] Fig.16 for Fig.12 Vertical axis chromatic aberration diagram of the provided optical module.

[0044] Description of reference numerals:

[0045] 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 retarder; 7. Polarized reflection element; 8. Polarizing element; 9. Anti-reflection film; 01. Human eye. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0047] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0048] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0049] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0050] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0051] The optical module and optical display device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0052] According to one embodiment of the present application, an optical module is provided, which is particularly suitable for use in a near-eye optical display device, especially a virtual reality (VR) display device, to provide an immersive visual experience. However, the application scope of this optical module is not limited to VR display devices, and it can also be flexibly applied to various other types of display devices to meet different visual needs and technical requirements.

[0053] The optical module proposed in the embodiment of the present application is shown in FIG. Figure 1 The optical module includes a lens group arranged along the same optical axis, as well as a spectroscopic element 5, a phase retarder 6 and a polarization reflection element 7, and the phase retarder 6 is located between the spectroscopic element 5 and the polarization reflection element 7; the lens group includes at least two lenses; there is at least one lens with negative optical focal length in the lens group, and the lens with negative optical focal length satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; wherein T1 is the thinnest thickness of the lens with negative optical focal length within the optical effective diameter, T2 is the thickest thickness of the lens with negative optical focal length within the optical effective diameter, and n and v are the refractive index and Abbe number of the lens with negative optical focal length, respectively.

[0054] The optical module provided in the embodiment of the present application, from the perspective of optical architecture, see Figure 1 , Figure 7 and Fig.12 , which includes optical elements such as a lens group, a beam splitter 5, a phase retarder 6 and a polarization reflection element 7. These optical elements are described below respectively.

[0055] The lens group is one of the core parts of the optical module of the present application, which is responsible for focusing, imaging and correcting aberration of light. In the present application, the lens group includes at least two lenses, and at least one lens with negative optical power. The introduction of negative optical power lenses helps to correct chromatic aberration problems in the optical module, thereby helping to improve imaging quality.

[0056] Although increasing the number of lenses can improve the imaging quality and correction capability of the optical module to a certain extent, too many lenses will also bring about a series of defects such as increased cost, increased structural complexity of the optical module, increased volume and weight, etc. Therefore, when designing an optical module, it is necessary to weigh the relationship between the number of lenses and the module performance, cost and complexity to select the optimal lens number configuration.

[0057] In the optical module provided in the embodiment of the present application, 2 to 4 lenses may be used in the lens group.

[0058] In addition to the lens group, the optical module provided in the embodiment of the present application also includes a plurality of optical film materials, such as a beam splitter 5 , a phase retarder 6 , and a polarization reflection element 7 .

[0059] The light splitting element 5 is, for example, a film or coating with specific light splitting properties, which can be used to reflect and transmit incident light in a certain proportion. Specifically, the light splitting element 5 can be a semi-transparent and semi-reflective film, which can transmit part of the light and reflect the other part of the light.

[0060] It should be noted that the reflectivity and transmittance of the light splitting element 5 can be flexibly adjusted according to specific needs, and this is not limited in the embodiments of the present application.

[0061] The phase retarder 6 can be used to change the polarization state of light, such as converting linear polarized light into circular polarized light, or converting circular polarized light into linear polarized light. The phase retarder 6 in the present application is, for example, a quarter wave plate, which is located between the beam splitter 5 and the polarized reflective element 7, and ensures that the light can be correctly reflected or transmitted in the subsequent path by adjusting the phase of the light.

[0062] The polarized reflective element 7 is a polarized reflector that reflects horizontal linear polarized light and transmits vertical linear polarized light, or a polarized reflector that reflects linear polarized light at any other specific angle and transmits linear polarized light in a direction perpendicular to the angle. In other words, the polarized reflective element 7 is responsible for reflecting or transmitting according to the polarization state of the light. In the optical module provided in the embodiment of the present application, it interacts with a specific state of polarized light (such as S light or P light) to achieve specific path control of the light.

[0063] In the optical module of the embodiment of the present application, the lens group includes at least one lens with negative focal length, and the Abbe number of the lens with negative focal length is specially set to be significantly different from the Abbe number of the lens with positive focal length. Such a design is intended to correct the chromatic aberration generated in the optical module, thereby significantly improving the imaging quality.

[0064] In addition, the design of the negative focal lens can also make the light more evenly distributed when passing through the lens group, effectively reducing the size of the light spot on the image plane. This improvement not only further enhances the clarity of the image, but also greatly improves the contrast of the picture, bringing users a better visual experience.

[0065] It should be noted that the Abbe number of a lens, also known as the dispersion coefficient, reflects the dispersion ability of the lens for light of different wavelengths.

[0066] In the embodiment of the present application, the parameter relationship is designed to be 3≤|(T1 / T2)*(v-50) / n|≤17. In this parameter relationship, the thickness ratio (T1 / T2), refractive index (n) and Abbe number (v) of the lens with negative optical focal length are reasonably controlled. The design of this parameter range makes it possible to reasonably match the refractive power of the lens with negative optical focal length under different wavelengths of light, thereby effectively reducing chromatic aberration. Chromatic aberration is one of the important factors affecting imaging quality. Through the design of the present application, image blur and color distortion caused by chromatic aberration can be significantly reduced.

[0067] In addition, "ghost images" are interfering images caused by multiple reflections and refractions of light on the surface of optical elements (such as lenses). The optical module provided by the present application reduces unnecessary reflections and refractions of light on the surface or inside of the lens by rationally arranging and designing parameters of the lens group, thereby reducing the generation of "ghost images". In particular, the parameter control of the negative focal lens makes the propagation path of light in the lens more reasonable, reduces the influence of stray light, and further improves the imaging quality.

[0068] In the present application, the lower limit of |(T1 / T2)*(v-50) / n| is designed to be 3, which avoids the unstable optical performance of the entire optical module caused by extreme conditions (such as T1 / T2, v-50 or n is too small).

[0069] Specifically, when the lower limit value is set to 3, it means that when designing a lens with negative optical focal length, it is necessary to ensure that the combination of the thickness ratio (T1 / T2), refractive index (n) and Abbe number (v) of the lens with negative optical focal length meets certain conditions to ensure the chromatic aberration and ghost correction capability of the optical module.

[0070] The upper limit value of |(T1 / T2)*(v-50) / n| is 17, and the upper limit value 17 limits the maximum value of the parameter to prevent the performance of the optical module from being reduced or the manufacturing difficulty from being increased due to the excessively large parameter.

[0071] Specifically, when the upper limit value is set to 17, it means that when designing a lens with negative optical focal length, it is necessary to balance the thickness ratio, refractive index and Abbe number of the lens to avoid additional aberrations or manufacturing difficulties introduced due to excessive parameters.

[0072] When |(T1 / T2)*(v-50) / n|<3, it may bring about the adverse effect of reduced chromatic aberration correction ability. If the parameter is lower than the lower limit of 3, it may mean that the thickness ratio, refractive index and Abbe number combination of the negative focal length lens cannot effectively correct chromatic aberration, resulting in reduced imaging quality. In addition, low parameter values ​​may make ghosting more obvious, affecting image clarity and contrast. In addition, too thin lenses or extreme refractive index / Abbe number combinations may increase manufacturing difficulty and cost.

[0073] When |(T1 / T2)*(v-50) / n|>17: Additional aberrations such as spherical aberration and coma may be introduced, thus affecting the imaging quality. Lens materials with high refractive index or special Abbe number may be more expensive, resulting in higher costs.

[0074] The optical module provided in the embodiment of the present application shows significant advantages in the field of VR optical display technology. By optimizing the design of the lens group, especially finely adjusting the parameters of the negative focal length lens, and matching optical components such as the beam splitter 5, the phase retarder 6 and the polarized reflective element 7, the optical module of the present application successfully achieves excellent optical effects of low chromatic aberration and low ghosting. This design of the present application greatly improves the clarity under the full field of view, thereby providing users with a more delicate and realistic visual experience. Specifically, the optical module of the present application effectively reduces the image blur and distortion caused by chromatic aberration and ghosting while ensuring the precise transmission of light, thereby ensuring the excellent performance of VR optical display equipment in high-end application scenarios such as commercial offices.

[0075] In some examples of the present application, the thickness of the lens with negative optical focal length in the lens group satisfies: T2 / T1≤3.

[0076] In this example of the present application, for the negative optical power lens in the lens group, a relationship is specifically set that its thickness should satisfy, namely, T2 / T1≤3. This design is intended to optimize the optical performance of the optical module, especially to reduce the "ghost" phenomenon.

[0077] Wherein, T2 represents the thickest thickness of the lens with negative optical power within the optical effective diameter. T1 represents the thinnest thickness of the lens with negative optical power within the optical effective diameter. By setting T2 / T1≤3, the thickness variation range of the lens with negative optical power is limited, ensuring that the thickness distribution of the lens is relatively uniform.

[0078] If a negative power lens is made of plastic material, its thickness ratio, i.e. T2 / T1, will significantly affect the stress distribution of the lens. Stress is the internal force generated inside the lens due to material unevenness, temperature changes or external forces, which may cause the lens to deform or produce optical distortion.

[0079] Specifically, the greater the difference in thickness between the thicker part (T2) and the thinner part (T1) on 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. The reduction in stress helps reduce reflections and scattering inside the lens, thereby reducing the occurrence of "ghosting" phenomena.

[0080] In this example of the present application, by constraining the ratio of T2 / T1, the stress generated by material unevenness or temperature change during the lens production process can be effectively reduced. The reduction of stress helps to maintain the shape stability of the lens and reduce lens deformation caused by stress.

[0081] It should be noted that "ghosting" is a stray light phenomenon caused by multiple reflections of light inside the lens, which affects the clarity and contrast of the image. The presence of stress will intensify the reflection and scattering inside the lens, thereby increasing the generation of ghosting. Therefore, by reducing stress, the ghosting phenomenon can be reduced and the clarity and contrast of the image can be improved.

[0082] The stable lens shape and reduced ghosting phenomenon together improve the optical performance of the lens assembly of the present application. This enables the optical module of the present application to transmit image information more accurately and meet the needs of high-definition VR applications.

[0083] The thickness ratio relationship (T2 / T1≤3) set for the negative power lens in the lens group in this application is intended to reduce the stress level in lens production, thereby reducing ghosting and improving the optical performance of the optical module. This design provides strong technical support for high-definition VR applications.

[0084] In some examples of the present application, in the lens group: the sum of the optical power of all lenses with negative optical power is φ m , the sum of the focal powers of all positive lenses is φ p ,φ m With φ p Satisfy between: 2≤|φ p / φ m |≤6.

[0085] In this application, a matching principle is proposed, that is, the sum of the focal lengths of all negative focal length lenses is φ m , the sum of the focal powers of all positive lenses is φ p , and the two satisfy 2≤|φ p / φ m |≤6. This matching principle aims to achieve the optimal transmission of light through the reasonable matching of positive and negative focal powers, thereby achieving the purpose of eliminating chromatic aberration.

[0086] It should be noted that chromatic aberration is caused by the different refractive indices of the lens for light of different wavelengths. When light passes through the lens, light of different wavelengths will be deflected to different degrees due to the different refractive indices, resulting in different focal points of light of different wavelengths on the image plane during imaging, which is chromatic aberration.

[0087] In the present application, by properly matching lenses with positive and negative optical powers, light of different wavelengths can be better focused on the same point after passing through the lens group of the present application, thereby eliminating chromatic aberration.

[0088] Specifically, the combination of positive and negative lenses can better control the light during transmission. Positive lenses can enhance the convergence of light, while negative lenses can weaken the convergence of light or make it diverge. By properly matching these two lenses, the light can be better kept parallel or focused on the same point after passing through the lens group.

[0089] In this application, by properly matching positive and negative focal length lenses and satisfying 2≤|φ p / φ m The matching principle of |≤6 can achieve low chromatic aberration and low ghosting effects, thereby improving the clarity and contrast of the optical module.

[0090] In some examples of this application, see Figure 1 , Figure 7 and Fig.12 , the lens group includes a first lens 3 and a second lens 4; the beam splitter 5 is arranged on the side of the first lens 3 away from the second lens 4, the phase retarder 6 and the polarization reflection element 7 are sequentially arranged on the side of the second lens 4 away from the first lens 3; the optical focal length of the first lens 3 is positive, the optical focal length of the second lens 4 is negative, and the difference in Abbe numbers between the first lens 3 and the second lens 4 is △v, |△v|≥14.

[0091] In this example of the present application, the lens group includes a first lens 3 and a second lens 4 adjacently arranged along the optical axis, the optical power of the first lens 3 is positive, and the optical power of the second lens 4 is negative. This combination of positive and negative optical powers helps to optimize the transmission path of light and improve imaging quality.

[0092] In this example of the present application, the beam splitter 5, the phase retarder 6 and the polarized reflective element 7 are disposed on both sides of the lens group, and can form a folded optical path in combination with the lens group, thereby reducing the volume of the optical module and improving the imaging quality.

[0093] The Abbe number is an important indicator to measure the dispersion ability of lens materials. It reflects the difference in refractive index of the lens for light of different wavelengths. The higher the Abbe number, the smaller the dispersion of the lens and the better the imaging quality.

[0094] In this example of the present application, the difference in Abbe number between the first lens 3 (a lens with positive power) and the second lens 4 (a lens with negative power) is Δv, and |Δv|≥14. This combination of positive and negative power, coupled with a large difference in Abbe number, helps introduce different dispersion characteristics into the lens group, thereby achieving correction of chromatic aberration.

[0095] Specifically, see Figure 1 The second lens 4 near the human eye 01 is a lens with negative optical focal length, and has an obvious difference in Abbe number from the first lens 3 (a lens with positive optical focal length) near the screen, which helps to achieve chromatic aberration correction.

[0096] By properly matching lenses with different Abbe numbers, light of different wavelengths can be better focused on the same point after passing through the lens group of the present application, thereby eliminating or reducing chromatic aberration. In the present application, the Abbe numbers of the first lens 3 and the second lens 4 are quite different, and this difference helps to introduce mutually offsetting dispersion effects in the lens group, thereby achieving correction of chromatic aberration.

[0097] In this application, by properly matching lenses with positive and negative optical powers and introducing a large difference in Abbe number, chromatic aberration can be effectively corrected and imaging quality can be improved. This is particularly important for VR optical display devices, because high definition is one of the key elements in the development of VR.

[0098] It should be noted that the lens group can also introduce 1 to 2 more lenses, and the newly added lenses can be placed on the side close to the human eye 01 or on the side close to the display screen 1. This is not limited in the present application and can be flexibly adjusted as needed.

[0099] In some examples of the present application, the thickness of the second lens 4 satisfies: T2 / T1≤3.

[0100] In this application, see Figure 1 , Figure 7 and Fig.12 , the second lens 4 is a lens with negative focal power in the lens group, and its thickness ratio satisfies T2 / T1≤3. This design aims to reduce the stress level in the production of the second lens 4, thereby reducing the "ghosting" phenomenon and improving the optical performance of the optical module. This design provides strong technical support for high-definition VR applications.

[0101] It should be noted that the second lens 4 is a lens with negative optical power, see Figure 1 , Figure 7 and Fig.12 , which is located on the side close to the human eye 01. In fact, when one lens is added to the lens group, the lens with negative optical power can also be located in the middle.

[0102] In some examples of this application, see Figure 1 , Figure 7 and Fig.12 , the focal length of the first lens 3 is φ p , the focal length of the second lens 4 is φ m , 2≤|φ p / φ m |≤6.

[0103] In this example of the present application, a specific matching principle is proposed, that is, the focal power of the second lens 4 with negative focal power is φ m The positive focal power of the first lens 3 is φ p , and the two satisfy 2≤|φ p / φ m |≤6. This combination aims to achieve optimal light transmission through a reasonable combination of positive and negative focal powers, thereby achieving the purpose of eliminating chromatic aberration.

[0104] In some examples of the present application, the thinnest thickness T1 of the second lens 4 within the optically effective diameter is 1.4 mm≤T1≤3.45 mm, and the thickest thickness T2 of the second lens 4 within the optically effective diameter is 3.7 mm≤T2≤3.8 mm.

[0105] For T1 and T2 within a given range, the ratio of T2 / T1 is always less than or equal to 3.

[0106] A thinner lens portion (T1) and an appropriate thickness ratio (T2 / T1≤3) help reduce stress accumulation during the production process. During the manufacturing process of the lens, stress may cause birefringence or other optical defects, affecting the image quality. By controlling the thickness ratio of the lens, these stresses can be reduced, thereby improving the optical performance and reliability of the lens.

[0107] In an optical module, reducing weight has a positive effect on improving wearing comfort, etc. In this example of the present application, by reasonably designing the thickness of the lens, the overall weight of the module can be reduced as much as possible while ensuring the optical performance.

[0108] In some examples of this application, see Figure 1 , Figure 7 and Fig.12The spectroscopic element 5 is arranged on the surface of the first lens 3 away from the second lens 4; the phase retarder 6 and the polarization reflection element 7 are stacked and arranged on the surface of the second lens 4 away from the first lens 3, and the phase retarder 6 is located between the spectroscopic element 5 and the polarization reflection element 7.

[0109] In the optical module provided in the present application, the first lens 3 is located on the side close to the screen, and includes two surfaces: a first surface 31 and a second surface 32. Figure 1 , the light splitting element 5 is directly arranged on the first surface 31 .

[0110] In the optical module provided in the present application, the second lens 4 is located on the side close to the human eye 01, and includes two surfaces: a third surface 41 and a fourth surface 42. Figure 1 The phase retarder 6 and the polarization reflection element 7 are stacked on the fourth surface 42.

[0111] The light splitting element 5, the phase retarder 6 and the polarized reflective element 7 are directly arranged on the surfaces of different lenses, which greatly improves the integration of the optical module. This tightly integrated structure not only reduces the gap between components, but also simplifies the overall architecture of the optical module, making the entire optical module more compact and lightweight.

[0112] The close combination of the light splitting element 5 and the lens surface helps to reduce aberrations and distortions caused by a long light path or an improper refraction angle. This design can ensure that the light still maintains a high imaging quality after light splitting, bringing a clearer and more realistic visual experience to users.

[0113] In some examples of this application, see Figure 1 , Figure 7 and Fig.12 The optical module further includes a polarizing element 8, which is disposed on a 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 material.

[0114] The polarizing element 8 , such as a polarizing film, can selectively transmit or reflect light vibrations in a specific direction.

[0115] In the optical module of the present application, by introducing the polarizing element 8 and arranging it on the side of the polarizing reflective element 7 away from the phase retarder 6, this design can reduce stray light interference.

[0116] Specifically, stray light is usually undesired light generated by reflection, scattering or refraction of light on an interface. By arranging the polarizing element 8 on the side of the polarizing reflective element 7 away from the phase retarder 6, stray light inconsistent with the direction of the main light can be filtered out, reducing their interference with the imaging quality. This helps to improve the contrast and clarity of the image, making the user more realistic and immersed when viewing the virtual image.

[0117] The reduction of stray light directly improves the image quality. In virtual reality applications, high-contrast and clear images are the basis for providing high-quality visual experience. The introduction of the polarizing element 8 enables the system to better control the propagation direction and state of light, reduce unnecessary light interference, and thus improve the overall image presentation effect.

[0118] 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 the propagation of stray light and energy loss, the optical module can use light energy more efficiently and concentrate more energy in the imaging process.

[0119] In this example of the present application, see Figure 2 The polarizing element 8, the polarizing reflecting element 7 and the phase retarder 6 are stacked to form a composite film material.

[0120] By stacking multiple optical components together, a highly integrated composite film is formed, which not only simplifies the structure of the optical module, but also significantly reduces the volume of the optical module. This integrated design helps to achieve lighter and thinner virtual reality devices, improving user wearing comfort and portability.

[0121] The close arrangement of the components in the composite film helps to optimize the propagation path of the light and reduce the energy loss and aberration of the light when it is transmitted between the components. In particular, the close cooperation between the phase retarder 6, the polarizing element 8 and the polarized reflective element 7 can more accurately control the polarization state and reflection direction of the light, thereby improving the imaging quality.

[0122] Traditional optical modules require the installation and adjustment of each component one by one, while the design of the composite film simplifies the assembly process. The composite film only needs to be installed into the system as a whole unit, thereby improving production efficiency.

[0123] Optionally, see Figure 2 In the composite film material, an anti-reflection film 9 can be introduced, and the setting of the anti-reflection film 9 can reduce the reflection of light on the surface of the lens, thereby increasing the transmittance of light. This can not only improve the brightness of the image, but also improve the overall optical performance of the optical module.

[0124] In some examples of this application, see Figure 1 , Figure 7 and Fig.12 The optical module further includes a display screen 1, and the display screen 1 is arranged along the optical axis on a side of the first lens 3 away from the second lens 4.

[0125] The display screen 1 is used for emitting imaging light.

[0126] Optionally, the optical module of the present application further comprises a superimposed element, the superimposed element comprising two phase retardation films and a polarizing film disposed between the two phase retardation films, and the superimposed element is disposed on the light-emitting surface of the display screen 1. The two phase retardation films are quarter-wave plates.

[0127] In this example of the present application, the combination of a phase delay film (as a quarter wave plate) and a polarizing film in the stacked element can effectively eliminate the reflected stray light of the display screen 1 itself. When the imaging light is emitted from the display screen 1, the circularly polarized light is converted into linearly polarized light in a specific direction through the conversion effect of a phase delay film. Subsequently, the polarizing film only allows the linearly polarized light in the specific direction to pass through, while blocking the linearly polarized light in other directions (including stray light reflected by the screen). Finally, another phase delay film converts the linearly polarized light into circularly polarized light again for subsequent optical processing. This process significantly reduces the interference of the reflection of the display screen 1 on the imaging quality and improves the clarity and contrast of the image.

[0128] Through the regulation of the overlapping elements, the loss of light during transmission is reduced, thereby improving the utilization rate of light, which helps to improve the brightness of the image.

[0129] The overlapping elements also help to enhance the color performance of the image. By optimizing the polarization state and phase of the light, the dispersion and chromatic aberration of the light during transmission can be reduced, making the color of the image more vivid and accurate. This is of great significance for enhancing the realism and immersion of the virtual reality experience.

[0130] Optionally, an anti-reflection film is introduced into the stacked element. The main function of the anti-reflection film is to reduce the reflection loss of light on the interface, thereby increasing the transmittance of light. In the optical module, each reflection of light will cause partial energy loss, reducing the overall efficiency of the optical module. Due to the reduction of light reflection loss, the energy distribution inside the optical module is more uniform, which is conducive to improving the uniformity and consistency of imaging.

[0131] In some examples of this application, see Figure 1 A protective glass 2 is arranged on the light-emitting surface of the display screen 1, and the total thickness of the protective glass 2 is ≥0.5 mm.

[0132] According to this example of the present application, this design effectively improves the tolerance of the optical solution to dirt on the surface of the display screen 1, reducing the risk of affecting the imaging quality due to screen contamination.

[0133] Specifically, the protective glass 2 in front of the display screen 1 can effectively isolate external dust, fingerprints, and other contaminants, thus keeping the surface of the display screen 1 clean. This is crucial for the optical module because any dirt on the screen surface may affect light transmission and image quality. By introducing the 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.

[0134] The protective glass 2 can not only isolate dirt but also effectively prevent the display screen 1 from being scratched, collided, and other physical damages. This is of great significance for extending the service life of the display screen 1 and improving the overall durability of the device.

[0135] For the optical module provided by the embodiment of the present application, the propagation of light is as follows. See Figure 1 :

[0136] 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 becomes linearly polarized light (P light) after being reflected by the beam splitter element 5 on the first surface 31 of the first lens 3 and 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.

[0137] For the optical module provided by the embodiment of the present application, see Figure 1 、 Figure 7 及 Fig.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 in the range of: 1.4 < n < 2.0, 20 < v < 75. This helps to reduce dispersion and other aberrations, improving the stability and imaging quality of the optical module.

[0138] 以 Figure 1 Taking the optical module shown as an example, the first lens 3 and the second lens 4 therein are described as follows.

[0139] The central thickness range of the first lens 3 is, for example: 1 mm ≤ T ≤ 8 mm. 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 element 5 is provided on the first surface 31, and the anti-reflection film layer can be provided on the second surface 32.

[0140] The central thickness range of the second lens 4 is: 1mm≤T≤10mm, and it includes two optical surfaces, namely a third surface 41 and a fourth surface 42, which are aspherical surfaces or planes. The fourth surface 42 is provided with a film structure, such as Figure 2 As shown, it includes 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 polarization element 8 (transmits P light). The third surface 41 is provided with an anti-reflection film layer.

[0141] The optical module provided by the present application is further described below through Examples 1 to 3.

[0142] Example 1

[0143] See also Figure 1 The optical module provided in this embodiment 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, and the phase retarder 6 is located between the beam splitter 5 and the polarization reflection element 7;

[0144] The lens group includes a first lens 3 and a second lens 4, the beam splitter 5 is disposed on a surface of the first lens 3 away from the second lens 4, and the phase retarder 6 and the polarization reflection element 7 are stacked and disposed on a surface of the second lens 4 away from the first lens 3;

[0145] 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 △v, |△v|≥14;

[0146] The thickness of the second lens 4 satisfies: T2 / T1≤3;

[0147] The focal length of the first lens 3 is φ p , the focal length of the second lens 4 is φ m , 2≤|φ p / φ m |≤6;

[0148] The second lens 4 satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; wherein T1 is the thinnest thickness of the second lens within the optically effective diameter, T2 is the thickest thickness of the second lens 4 within the optically effective diameter, and n and v are the refractive index and Abbe number of the second lens 4, respectively;

[0149] The optical module further comprises a polarizing element 8, which is disposed on a side of the polarizing reflective element 7 away from the phase retarder 6, and the polarizing element 8, the polarizing reflective element 7 and the phase retarder 6 form a composite film material, see Figure 2 ;

[0150] The optical module further comprises a display screen 1, which is arranged along the optical axis on a side of the first lens 3 away from the second lens 4, and a protective glass 2 is arranged on the light-emitting surface of the display screen, and the total thickness of the protective glass 2 is ≥0.5 mm.

[0151] Table 1 shows the specific optical parameters of the optical module of this embodiment 1.

[0152] Table 1

[0153] surface Radius(mm) Thickness(mm) Material Conic A2 A4 A6 A8 A10 A12 A14 42 -22.2710 3.7948 H-QK3L 0.4229 0.0000 -1.306E-06 1.092E-07 3.294E-10 -9.532E-13 6.578E-17 4.719E-18 41 -17.3170 0.6252 Air -0.1652 0.0000 7.424E-05 -2.763E-07 -1.434E-10 2.919E-12 -1.441E-15 0.000E+00 32 -16.6746 3.0000 APEL -5.1769 0.0000 -2.810E-05 -3.146E-08 4.496E-11 -1.386E-13 2.496E-15 -1.260E-17 31 -21.9660 0.6000 Air -3.9869 0.0000 -3.897E-05 2.815E-08 5.460E-11 1.323E-13 -1.504E-15 2.220E-18

[0154] In addition, Table 4 after Example 3 shows other parameters involved in this Example 1.

[0155] The optical performance of the optical module provided in this embodiment 1 can be as follows: Figure 3 Figure 6 As shown: Figure 3 is a schematic diagram of the point diagram. Figure 4 is the MTF curve graph, Figure 5 is the field curvature distortion diagram, Figure 6 This is the vertical axis chromatic aberration diagram.

[0156] The spot diagram refers to a diffuse diagram formed by the intersection of many light rays emitted from one point and the image plane after passing through the optical module. Due to aberration, the intersection points of the light rays with the image plane are no longer concentrated at the same point, but are spread over a certain range. It is used to evaluate the imaging quality of the projection optical module. Figure 3 In the optical module provided in the first embodiment, the maximum value of the image point in the point diagram is less than 7 μm.

[0157] The MTF curve is a modulation transfer function graph that characterizes the imaging clarity of an optical module through the contrast of black and white line pairs. Figure 4 The optical module provided in this embodiment 1 has an MTF of >0.3 at 35lp / mm.

[0158] See also Figure 5 In the optical module provided in the first embodiment, the maximum distortion occurs in one field of view, and the absolute value is less than 35%.

[0159] Vertical axis chromatic aberration is also called magnification chromatic aberration. It mainly refers to the difference between the focal positions of blue light and red light on the image plane. Figure 6 The optical module provided in this embodiment 1 has a maximum color difference value of less than 65 μm.

[0160] Example 2

[0161] See also Figure 7The optical architecture of this embodiment 2 is the same as that of the above-mentioned embodiment 1. For the differences, please refer to Table 2 below and Table 4 shown after embodiment 3.

[0162] Table 2 shows the specific optical parameters of the optical module of this embodiment 2.

[0163] Table 2

[0164]

[0165]

[0166] The optical performance of the optical module provided in this embodiment 2 can be as follows: Figure 8 Fig.11 As shown: Figure 8 is a schematic diagram of the point diagram. Fig. 9 is the MTF curve graph, Fig.10 is the field curvature distortion diagram, Fig.11 This is the vertical axis chromatic aberration diagram.

[0167] See also Figure 8 In the optical module provided in the second embodiment, the maximum value of the image point in the point array diagram is less than 10 μm.

[0168] See also Fig. 9 The optical module provided in this embodiment 2 has an MTF of >0.3 at 35lp / mm.

[0169] See also Fig.10 In the optical module provided in the second embodiment, the maximum distortion occurs in one field of view, and the absolute value is less than 35%, and the distortion is very small.

[0170] See also Fig.11 The optical module provided in this embodiment 2 has a maximum chromatic aberration value of less than 65 μm.

[0171] Example 3

[0172] See also Fig.12 The optical architecture of this embodiment 3 is the same as that of the above-mentioned embodiment 1. For the differences, please refer to Table 3 below and Table 4 shown after embodiment 3.

[0173] Table 3 shows the specific optical parameters of the optical module of this embodiment 3.

[0174] Table 3

[0175] surface Radius(mm) Thickness(mm) Material Conic A2 A4 A6 A8 A10 A12 A14 42 -51.5544 3.6998 OKP4 4.5441 0.0000 2.142E-05 5.415E-09 -7.987E-12 6.756E-15 1.322E-16 0.000E+00 41 -26.7071 0.3362 -0.8295 0.0000 1.349E-04 -7.051E-07 2.368E-09 -4.405E-12 3.532E-15 0.000E+00 32 -26.2687 6.0997 APEL -0.4590 0.0000 1.991E-04 -1.133E-06 4.137E-09 -8.786E-12 7.762E-15 0.000E+00 31 -35.0327 0.6000 Air -13.9059 0.0000 -2.878E-05 1.480E-07 -6.577E-10 2.259E-12 -4.803E-15 4.214E-18

[0176] The optical performance of the optical module provided in this embodiment 3 can be as follows: Fig.13 Fig.16 As shown: Fig.13 is a schematic diagram of the point diagram. Fig.14is the MTF curve graph, Fig.15 is the field curvature distortion diagram, Fig.16 This is the vertical axis chromatic aberration diagram.

[0177] See also Fig.13 In the optical module provided in the third embodiment, the maximum value of the image point in the point diagram is less than 33 μm.

[0178] See also Fig.14 The optical module provided in this embodiment 3 has an MTF of >0.3 at 35lp / mm.

[0179] See also Fig.15 In the optical module provided in the present embodiment 3, the maximum distortion occurs in 1 field of view, and the absolute value is less than 35%, and the distortion is very small.

[0180] See also Fig.16 , the optical module provided in this embodiment 3 has a maximum chromatic aberration value less than 65 μm.

[0181] Table 4 Parameters in Examples 1 to 3

[0182] T1 thinnest / mm T2 thickest / mm Refractive Index Abbe number Example 1 1.4 3.8 1.487 70.4 Example 2 3.2 3.7 1.75 27.5 Example 3 3.45 3.7 1.63 23.3

[0183] According to another embodiment of the present application, an optical display device is provided, which includes: a housing and the optical module as described above.

[0184] The optical display device provided in the embodiment of the present application is, for example, a VR display device.

[0185] The specific implementation of the optical display device of the embodiment of the present application can refer to the above-mentioned optical module embodiments, so it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0186] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0187] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An optical module, characterized in that: The invention comprises a lens group arranged along the same optical axis, a beam splitter (5), a phase retarder (6) and a polarized reflective element (7), wherein the phase retarder (6) is located between the beam splitter (5) and the polarized reflective element (7); The lens group includes at least two lenses; The lens group comprises at least one lens with negative optical power, and the lens with negative optical power satisfies: 3≤|(T1 / T2)*(v-50) / n|≤17; wherein T1 is the thinnest thickness of the lens with negative optical power within the optically effective diameter, T2 is the thickest thickness of the lens with negative optical power within the optically 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 lens with negative focal power 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 focal lengths of all negative focal length lenses is φ m , the sum of the focal powers of all positive lenses is φ p ,φ m With φ p Satisfy between: 2≤|φ p / φ m |≤6.

4. The optical module according to any one of claims 1 to 3, characterized in that: The lens group comprises a first lens (3) and a second lens (4); The beam splitter (5) is arranged on a side of the first lens (3) away from the second lens (4), and the phase retarder (6) and the polarization reflection element (7) are arranged in sequence on a side of the second lens (4) away from the first lens (3); The optical focal power of the first lens (3) is positive, the optical focal 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.

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 focal power of the first lens (3) is φ p , the focal 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 1.4 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.

8. The optical module according to claim 4, characterized in that: The light splitting element (5) is arranged on a surface of the first lens (3) facing away from the second lens (4); The phase retarder (6) and the polarized reflective element (7) are stacked on a surface of the second lens (4) facing away from the first lens (3), and the phase retarder (6) is located between the beam splitting element (5) and the polarized reflective element (7).

9. The optical module according to claim 8, characterized in that: The optical module further comprises a polarizing element (8), wherein the polarizing element (8) is arranged on a side of the polarizing reflection element (7) away from the phase retarder (6); The polarizing element (8), the polarizing reflection element (7) and the phase retarder (6) form a composite film material.

10. The optical module according to claim 4, characterized in that: The optical module further comprises a display screen (1), wherein the display screen (1) is arranged along the optical axis on a side of the first lens (3) away from the second lens (4).

11. The optical module according to claim 10, characterized in that: 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 ≥0.5 mm.

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

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