Optical module and head-mounted display device

Abstract

The utility model provides an optical module and a head-mounted display device, and relates to the technical field of optical modules, the optical module comprises a first optical element and a second optical element; the first optical element comprises a first lens and an optical splitter; the second optical element comprises a second lens, a polarization reflector and a phase retarder; the curvature radius of the S1 surface, located on the screen side, of the first lens is defined as RL1S1, the curvature radius of the S2 surface, located on the human eye side, of the first lens is defined as RL1S2, the curvature radius of the S1 surface, located on the screen side, of the second lens is defined as RL2S1, and the curvature radius of the S2 surface, located on the human eye side, of the second lens is defined as RL2S2. (RL1S1 + RL1S2) / (RL1S1-RL1S2) + (RL2S1 + RL2S2) / (RL2S1-RL2S2) lt; 14. The utility model has the advantages of small size and high imaging quality.

Description

Technical Field

[0001] The utility model relates to the technical field of optical modules, and particularly relates to an optical module and a head-mounted display device. Background Art

[0002] The core of a head-mounted display device is the internal optical module, which plays a decisive role in its imaging quality. With the progress of technology, the size of the display screen is getting smaller and the resolution is getting higher. Coupled with the increasing demand of consumers for the imaging quality of head-mounted display devices, the experience is required to be improved. Therefore, the requirements for the optical module are also increasing. Therefore, designing an optical module with a thinner thickness, a smaller volume and a higher imaging quality has become an urgent problem to be solved at present.

[0003] In view of this, it is necessary to provide a new optical module and a head-mounted display device to solve or at least alleviate the above technical defects. Summary of the Utility Model

[0004] The main purpose of the utility model is to provide an optical module and a head-mounted display device, aiming to solve the technical problem of how to design an optical module with both small size and high imaging quality.

[0005] To achieve the above object, according to one aspect of the utility model, the utility model provides an optical module, including a first optical element and a second optical element;

[0006] The first optical element includes a first lens and a beam splitter;

[0007] The second optical element includes a second lens, a polarization reflector and a phase retarder;

[0008] The beam splitter, the first lens, the phase retarder, the polarization reflector and the second lens are arranged in sequence along the same optical axis;

[0009] The side of the first optical element away from the second optical element is the screen side, and the side of the second optical element away from the first optical element is the human eye side. Define the radius of curvature of the S1 surface of the first lens on the screen side as R L1S1 , and the radius of curvature of the S2 surface of the first lens on the human eye side as R L1S2 , the radius of curvature of the S1 surface of the second lens on the screen side as R L2S1 , and the radius of curvature of the S2 surface of the second lens on the human eye side as R L2S2 , then there is:

[0010] 8 < (R L1S1 + R L1S2 ) / (R L1S1 - R L1S2 ) + (RL2S1 +R L2S2 ) / (R L2S1 -R L2S2 ) < 14

[0011] In some embodiments, the overall optical focal length of the optical module is defined as FG, the central thickness of the first lens is CT1, the central thickness of the second lens is CT2, and the air gap between the first lens and the second lens is GAP. Then:

[0012] 4.5 < FG / (CT1 + GAP) + FG / (CT2 + GAP) < 9

[0013] In some embodiments, on the side facing the screen side near the optical axis, both the first lens and the second lens are convex, and on the side facing the human eye side near the optical axis, both the first lens and the second lens are concave.

[0014] In some embodiments, the optical module further includes an image display unit, and the image display unit is disposed on the screen side.

[0015] In some embodiments, the optical module further includes a first quarter-wave plate, and the first quarter-wave plate is disposed on the side of the image display unit facing the beam splitter.

[0016] In some embodiments, the beam splitter includes a semi-transmissive and semi-reflective film, and the semi-transmissive and semi-reflective film is attached to the side of the first lens away from the second lens.

[0017] In some embodiments, the phase retarder and the polarization reflector are stacked, and the polarization reflector is disposed on the surface of the second lens.

[0018] In some embodiments, the polarization reflector includes a polarization reflective sheet, the phase retarder includes a second quarter-wave plate, the polarization reflective sheet is attached to the side of the second lens facing the first lens, and the second quarter-wave plate is attached to the side of the polarization reflective sheet away from the second lens.

[0019] According to another aspect of the present invention, the present invention further provides a head-mounted display device, and the head-mounted display device includes the above-mentioned optical module.

[0020] In some embodiments, the head-mounted display device is any one of a virtual display device, an augmented reality device, or a mixed reality device.

[0021] In the above solution, the optical module includes a first optical element and a second optical element; the first optical element includes a first lens and a beam splitter; the second optical element includes a second lens, a polarization reflector, and a phase retarder; the beam splitter, the first lens, the phase retarder, the polarization reflector, and the second lens are arranged in sequence along the same optical axis; define the overall optical focal length of the optical module as FG, the central thickness of the first lens as CT1, the central thickness of the second lens as CT2, and the air gap between the first lens and the second lens as GAP, then: 4.5 < FG / (CT1 + GAP) + FG / (CT2 + GAP) < 9; the side of the first lens away from the second lens is the screen side, and the side of the second lens away from the first lens is the human eye side. Define the radius of curvature of the S1 surface of the first lens on the screen side as R L1S1 , the radius of curvature of the S2 surface of the first lens on the human eye side is R L1S2 , the radius of curvature of the S1 surface of the second lens on the screen side is R L2S1 , the radius of curvature of the S2 surface of the second lens on the human eye side is R L2S2 , then: 8 < (R L1S1 + R L1S2 ) / (R L1S1 - R L1S2 ) + (R L2S1 + R L2S2 ) / (R L2S1 - R L2S2 ) < 14. By defining the relationship between the radii of curvature of each surface of the first lens and the second lens, as well as the relationship between the parameters of the overall optical focal length FG of the optical module, the central thickness CT1 of the first lens, the central thickness CT2 of the second lens, and the air gap GAP between the first lens and the second lens, and adopting a folded optical path, the utility model can ensure the imaging quality on the premise of reducing the thickness of the optical module. At the same time, reducing the thickness of the optical module also reduces the weight and volume of the head-mounted display device. The utility model has the advantages of small size and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0023] Figure 1 is an exploded structural schematic diagram of the optical module according to an embodiment of the present utility model;

[0024] Figure 2This is a structural schematic diagram of the optical path of the optical module of the embodiment of the utility model;

[0025] Figure 3 It is a partial structural schematic diagram of an optical module according to an embodiment of the utility model;

[0026] Figure 4 This is one of the partial structural schematic diagrams of the optical module of Embodiment 1 of the utility model;

[0027] Figure 5 for Figure 4 One of the dot array diagrams of the optical module shown;

[0028] Figure 6 for Figure 4 One of the modulation transfer function MTF curves of the optical module shown;

[0029] Figure 7 for Figure 4 One of the field curvature and distortion diagrams of the optical module shown;

[0030] Figure 8 for Figure 4 One of the vertical axis chromatic aberration diagrams of the optical module shown;

[0031] Figure 9 This is the second schematic diagram of the partial structure of the optical module of Embodiment 2 of the present utility model;

[0032] Figure 10 for Figure 9 The second dot array diagram of the optical module is shown;

[0033] Figure 11 for Figure 9 The second modulation transfer function MTF curve diagram of the optical module is shown;

[0034] Figure 12 for Figure 9 The second diagram of field curvature and distortion of the optical module is shown;

[0035] Figure 13 for Figure 9 The second vertical axis chromatic aberration diagram of the optical module is shown;

[0036] Figure 14 This is a third schematic diagram of a partial structure of an optical module of Embodiment 3 of the present utility model;

[0037] Figure 15 for Figure 14 The third dot array diagram of the optical module is shown;

[0038] Figure 16 for Figure 14 The third modulation transfer function MTF curve diagram of the optical module is shown;

[0039] Figure 17 The third of the field curvature and distortion diagrams of the optical module shown; Figure 14

[0040] Figure 18 The third of the lateral chromatic aberration diagrams of the optical module shown; Figure 14

[0041] Figure 19 The fourth of the partial structure diagrams of the optical module according to Embodiment 4 of the present invention;

[0042] Figure 20 The fourth of the dot array diagrams of the optical module shown; Figure 19

[0043] Figure 21 The fourth of the modulation transfer function MTF curve diagrams of the optical module shown; Figure 19

[0044] Figure 22 The fourth of the field curvature and distortion diagrams of the optical module shown; Figure 19

[0045] Figure 23 The fourth of the lateral chromatic aberration diagrams of the optical module shown; Figure 19

[0046] Figure 24 The fifth of the partial structure diagrams of the optical module according to Embodiment 5 of the present invention;

[0047] Figure 25 The fifth of the dot array diagrams of the optical module shown; Figure 24

[0048] Figure 26 The fifth of the modulation transfer function MTF curve diagrams of the optical module shown; Figure 24

[0049] Figure 27 The fifth of the field curvature and distortion diagrams of the optical module shown; Figure 24

[0050] Figure 28 The fifth of the lateral chromatic aberration diagrams of the optical module shown; Figure 24

[0051] Figure 29 The sixth of the partial structure diagrams of the optical module according to Embodiment 6 of the present invention;

[0052] Figure 30 The sixth of the dot array diagrams of the optical module shown; Figure 29

[0053] Figure 31 The fourth of the modulation transfer function MTF curve diagrams of the optical module shown; Figure 29 ​​​​​​​​​​​The sixth modulation transfer function (MTF) curve graph of the shown optical module;

[0054] Figure 32 is Figure 29 The sixth field curvature and distortion graph of the shown optical module;

[0055] Figure 33 is Figure 29 The sixth lateral chromatic aberration graph of the shown optical module;

[0056] Figure 34 The seventh partial structural schematic diagram of the optical module according to Embodiment 7 of the present invention;

[0057] Figure 35 is Figure 34 The seventh dot array graph of the shown optical module;

[0058] Figure 36 is Figure 34 The seventh modulation transfer function (MTF) curve graph of the shown optical module;

[0059] Figure 37 is Figure 34 The seventh field curvature and distortion graph of the shown optical module;

[0060] Figure 38 is Figure 34 The seventh lateral chromatic aberration graph of the shown optical module.

[0061] Reference numeral description:

[0062] 100. Optical module; 1. Beam splitter; 2. First lens; 3. Phase retarder; 4. Polarizing reflector; 5. Second lens; 6. Image display unit; 7. First quarter-wave plate; A. Optical axis; B. Screen side; C. Human eye side.

[0063] The realization, functional features and advantages of the purpose of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. Specific embodiments

[0064] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0065] It should be noted that all directional indications (such as up, down,...) in the embodiments of the present utility model are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications will also change accordingly.

[0066] In addition, in the present utility model, descriptions such as "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0067] Moreover, the technical solutions between various embodiments of the present utility model can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0068] Therefore, the present utility model provides an optical module.

[0069] Referring to Figures 1 - 3 , according to one aspect of the present utility model, the present utility model provides an optical module 100, including a first optical element and a second optical element;

[0070] The first optical element includes a first lens 2 and a beam splitter 1;

[0071] The second optical element includes a second lens 5, a polarization reflector 4, and a phase retarder 3;

[0072] The beam splitter 1, the first lens 2, the phase retarder 3, the polarization reflector 4, and the second lens 5 are arranged in sequence along the same optical axis A;

[0073] Define the overall optical focal length of the optical module 100 as FG, the central thickness of the first lens 2 as CT1, the central thickness of the second lens 5 as CT2, and the air gap between the first lens 2 and the second lens 5 as GAP. Then there is:

[0074] 4.5 < FG / (CT1 + GAP) + FG / (CT2 + GAP) < 9;

[0075] The side of the first optical element away from the second optical element is the screen side B, and the side of the second optical element away from the first optical element is the human eye side C. Define the radius of curvature of the S1 surface of the first lens 2 on the screen side B as RL1S1, the radius of curvature of the S2 surface of the first lens 2 on the human eye side C as RL1S2, the radius of curvature of the S1 surface of the second lens 5 on the screen side B as RL2S1, and the radius of curvature of the S2 surface of the second lens 5 on the human eye side C as RL2S2. Then there is:

[0076] 8 < (R L1S1 + R L1S2 ) / (R L1S1 - R L1S2 ) + (R L2S1 + R L2S2 ) / (R L2S1 - R L2S2 ) < 14.

[0077] The optical axis A, the screen side B, and the human eye side C are as Figure 1 shown. The overall optical focal length refers to the distance from the focus of the optical module to the principal plane. In the above embodiment, the screen side B refers to the side where the image display unit 6 is provided, and the image display unit 6 can be a display or a display device. The light emitted by the image display unit 6 may be natural light or polarized light. If the emitted light is natural light, a polarizer can be added in front of the image display unit 6 to convert the natural light into linearly polarized light, and then a first quarter-wave plate 7 can be added to convert the linearly polarized light into circularly polarized light. Specifically, referring to Figure 1 and Figure 2 , Figure 2 where S represents S linearly polarized light, P represents P linearly polarized light, LCP represents left-handed circularly polarized light, and RCP represents right-handed circularly polarized light. For the sake of clearly showing the direction of light, Figure 2 does not show the positions of the first lens 2 and the second lens 5, and can be combined with Figure 1 for reference. Taking the light emitted from the image display unit 6 as S linearly polarized light as an example, the S linearly polarized light is converted into right-handed circularly polarized light after passing through the first quarter-wave plate 7. After passing through the beam splitter 1, part of the light is transmitted and incident on the first lens 2, and the polarization state does not change at this time; after exiting from the first lens 2, it becomes P linearly polarized light for the first time after passing through the phase retarder 3. The polarization reflector 4 is designed to reflect P linearly polarized light and transmit S linearly polarized light. The polarization state of the P linearly polarized light does not change after being reflected by the polarization reflector 4, and it becomes right-handed circularly polarized light again after passing through the phase retarder 3 for the second time and is incident on the first lens 2 again. After being reflected by the polarization reflector 4, the phase is delayed by π, and the right-handed circularly polarized light becomes left-handed circularly polarized light. The left-handed circularly polarized light passes through the first lens 2 for the third time and is incident on the phase retarder 3 to become S linearly polarized light. The S linearly polarized light passes through the polarization reflector 4 and finally converges on the human eye side C and is received by the human eye.

[0078] In addition, in this embodiment, by defining the relationship between the radius of curvature of each surface of the first lens 2 and the second lens 5, as well as the relationship between the overall optical focal length FG of the optical module 100, the central thickness CT1 of the first lens 2, the central thickness CT2 of the second lens 5, and the air gap GAP between the first lens 2 and the second lens 5, and adopting a folded optical path, it is possible to ensure the imaging quality while reducing the thickness of the optical module 100. At the same time, reducing the thickness of the optical module 100 also reduces the weight and volume of the head-mounted display device. This embodiment has the advantages of small size and high imaging quality.

[0079] In some embodiments, on the side facing the screen side B near the optical axis A, both the first lens 2 and the second lens 5 are convex surfaces, and on the side facing the human eye side C near the optical axis A, both the first lens 2 and the second lens 5 are concave surfaces. The position near the optical axis A refers to the position close to the optical axis A. The screen side B is the side where the image display unit 6 is provided. The human eye side C can also be the aperture side or the location of the human eye. In the embodiments of the present invention, by deflecting and folding the optical path, the optical path length of the light in the optical module 100 is increased. And on the side facing the screen side B near the optical axis A, both the first lens 2 and the second lens 5 are convex surfaces, and on the side facing the human eye side C near the optical axis A, both the first lens 2 and the second lens 5 are concave surfaces. Both the first lens 2 and the second lens 5 have positive refractive power, and there is a mutual compensation relationship between the two lenses. Therefore, the requirement for the deflection angle of the imaging light by each lens is reduced, making the thickness of the lens smaller, which is beneficial to realizing the requirement of thinning while ensuring the imaging quality, and is beneficial to reducing the volume and mass of the optical module.

[0080] In some embodiments, the optical module 100 further includes an image display unit 6, and the image display unit 6 is provided on the screen side B. As described above, the image display unit 6 can be a display device or a display module. As a part of the optical module 100, if the image display unit 6 can emit circularly polarized light, there is no need to provide a quarter-wave plate. If the image display unit 6 emits linearly polarized light, a first quarter-wave plate 7 needs to be provided to convert the linearly polarized light into circularly polarized light. If the image display unit 6 emits natural light, a polarizer needs to be added. First, the natural light is converted into linearly polarized light, and then it is converted into circularly polarized light by the first quarter-wave plate 7.

[0081] Regarding the position of the first quarter-wave plate 7, the first quarter-wave plate 7 can be provided on the side of the image display unit 6 facing the beam splitter 1, that is, between the image display unit 6 and the beam splitter 1. Specifically, it can be attached to the image display unit 6, or attached to the beam splitter 1, or spaced from both the image display unit 6 and the beam splitter 1.

[0082] In some embodiments, the beam splitter 1 includes a semi-transmissive and semi-reflective film, which is attached to the side of the first lens 2 away from the second lens 5. The beam splitter 1 can transmit a part of the light and reflect another part of the light. A support member can be provided separately for the semi-transmissive and semi-reflective film, or the semi-transmissive and semi-reflective film can be directly attached to the surface of the first lens 2. Of course, in other embodiments, if the first quarter-wave plate 7 is attached to the image display unit 6, the semi-transmissive and semi-reflective film can also be attached to the side of the first quarter-wave plate 7 away from the image display unit 6.

[0083] In some embodiments, the phase retarder 3 and the polarization reflector 4 are stacked, and the polarization reflector 4 is disposed on the surface of the second lens 5. In a specific embodiment, the polarization reflector 4 includes a polarization reflection sheet, the phase retarder 3 includes a second quarter-wave plate, the polarization reflection sheet is attached to the side of the second lens 5 facing the first lens 2, and the second quarter-wave plate is attached to the side of the polarization reflection sheet away from the second lens 5. Both the polarization reflector 4 and the phase retarder 3 can be diaphragms, and it is relatively simple to manufacture and install diaphragms. The polarization reflection sheet can transmit light with certain polarization directions and reflect light with other polarization directions. For example, it can be designed to reflect P-line polarized light and transmit S-line polarized light, or reflect S-line polarized light and transmit P-line polarized light. Those skilled in the art can set it according to actual needs.

[0084] Hereinafter, the optical performance of the optical module 100 provided by the embodiments of the present application will be described through Embodiments 1 to 7. The optical module 100 includes a first optical element, a second optical element, and an image display unit 6. The first optical element includes a first lens 2 and a beam splitter 1. The second optical element includes a second lens 5, a polarization reflector 4, and a phase retarder 3. The beam splitter 1, the first lens 2, the phase retarder 3, the polarization reflector 4, and the second lens 5 are arranged in sequence along the same optical axis A.

[0085] Embodiment 1

[0086] In Embodiment 1, referring to Figure 4 , the total length of the entire optical module is about 19.50 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 20.29 mm, the central thickness CT1 of the first lens is 6 mm, the central thickness CT2 of the second lens is 6 mm, and the air gap GAP between the first lens and the second lens is 3 mm. At this time: FG / (CT1 + GAP) + FG / (CT2 + GAP) = 4.51. The central thickness CT1, the central thickness CT2, and the air gap GAP are shown in the thickness / spacing column in Table 1, and the same applies to Tables 2 to 7.

[0087] The surfaces of the first lens and the second lens are both even aspherical surfaces. For the radius of curvature and other parameters of the first lens and the second lens, see Table 1 below. Among them, A2 - A12 are the even aspherical coefficients corresponding to the second term to the twelfth term respectively. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 9.63.

[0088] Table 1

[0089]

[0090] In Example 1, the system parameters and performance are as follows:

[0091] Refer to Figure 5 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 8 microns, and the imaging is clear.

[0092] Refer to Figure 6 , Figure 6 The abscissa in

[0093] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 7 The abscissa of the left figure represents the field curvature. Figure 7 The abscissa of the right figure represents the distortion. It can be seen that the maximum field curvature does not exceed 0.2 mm, and the distortion is not greater than 30%, and the field curvature and distortion are small.

[0094] Chromatic aberration reflects the differences in the imaging positions of light with different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 1 Figure 8 as shown in Figure 8 The abscissa represents the chromatic aberration, and the ordinate represents the field of view angle. The maximum field chromatic aberration is less than 143 um, and the field chromatic aberration is small, and the imaging is clear and accurate.

[0095] Example 2

[0096] Refer to Figure 9 , in Example 2, the total length of the entire optical module is about 19.90 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 22.60 mm, the central thickness CT1 of the first lens is 3 mm, the central thickness CT2 of the second lens is 3.05 mm, and the air gap GAP between the first lens and the second lens is 2 mm. At this time: FG / (CT1 + GAP) + FG / (CT2 + GAP) = 8.99.

[0097] The surfaces of the first lens and the second lens are both even aspherical surfaces. For the radius of curvature and other parameters of the first lens and the second lens, see Table 2 below. Among them, A2 - A12 are the even aspherical coefficients corresponding respectively, which are the quadratic term to the twelfth term. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 13.72.

[0098] Table 2

[0099]

[0100] In Example 2, the system parameters and performance are as follows:

[0101] Refer to Figure 10 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 7 microns, and the imaging is clear.

[0102] Refer to Figure 11 , Figure 10 The abscissa in

[0103] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 11 The abscissa of the left figure represents the field curvature. Figure 11 The abscissa of the right figure represents the distortion. It can be seen that the maximum field curvature does not exceed 0.5 mm, and the distortion is not greater than 30%. The field curvature and distortion are small.

[0104] Chromatic aberration reflects the differences in the imaging positions of light with different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 2 Figure 13 is shown as Figure 13 The abscissa represents the chromatic aberration, and the ordinate represents the field angle. The maximum field chromatic aberration is less than 138 um, and the field chromatic aberration is small, and the imaging is clear and accurate.

[0105] Example 3

[0106] Refer to Figure 14 , in Example 3, the total length of the entire optical module is about 16.52 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 21.13 mm, the central thickness CT1 of the first lens is 3.12 mm, the central thickness CT2 of the second lens is 3.41 mm, and the air gap GAP between the first lens and the second lens is 3.47 mm. At this time: FG / (CT1 + GAP) + FG / (CT2 + GAP) = 6.27.

[0107] The surfaces of the first lens and the second lens are both even aspherical surfaces. For the radius of curvature and other parameters of the first lens and the second lens, see Table 3 below. Among them, A2 - A12 are the even aspherical coefficients corresponding respectively, which are from the quadratic term to the twelfth term. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 13.99.

[0108] Table 3

[0109]

[0110] In Example 3, the system parameters and performance are as follows:

[0111] Refer to Figure 15 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 5 microns, and the imaging is clear.

[0112] Refer to Figure 16 , Figure 16 The abscissa in

[0113] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 11 The abscissa of the left figure represents the field curvature. Figure 11 The abscissa of the right figure represents the distortion. It can be seen that the maximum field curvature does not exceed 0.2 mm, and the distortion is not greater than 30%. The field curvature and distortion are small.

[0114] Chromatic aberration reflects the differences in the imaging positions of light of different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 3 Figure 18 as shown in Figure 18 The abscissa represents the chromatic aberration, and the ordinate represents the field of view angle. The maximum field chromatic aberration is less than 138 um, and the field chromatic aberration is small, and the imaging is clear and accurate.

[0115] Example 4

[0116] Refer to Figure 19 , in Example 4, the total length of the entire optical module is about 15.47 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 18.12 mm, the central thickness CT1 of the first lens is 5.06 mm, the central thickness CT2 of the second lens is 4.02 mm, and the air gap GAP between the first lens and the second lens is 2.84 mm. At this time: FG / (CT1 + GAP) + FG / (CT2 + GAP) = 4.94.

[0117] The surfaces of the first lens and the second lens are both even aspherical surfaces. The curvature radii and other parameters of the first lens and the second lens are shown in Table 4 below. Among them, A2 - A12 are the even aspherical coefficients corresponding to the second term to the twelfth term respectively. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 8.01.

[0118] Table 4

[0119]

[0120] In Example 4, the system parameters and performance are as follows:

[0121] Refer to Figure 20 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 6 microns, and the imaging is clear.

[0122] Refer to Figure 21 , Figure 21 The abscissa of the left figure represents the field curvature, Figure 11 The abscissa of the right figure represents the distortion. It can be seen that at 40 line pairs per millimeter, the MTF (modulation transfer function) value is higher than 0.5, indicating the good resolution of the model.

[0123] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 22 The abscissa of the left figure represents the field curvature, Figure 22 The abscissa of the right figure represents the distortion. It can be seen that the maximum field curvature does not exceed 0.5 mm and the distortion is not greater than 30%, and the field curvature and distortion are small.

[0124] Chromatic aberration reflects the differences in the imaging positions of light of different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 4 Figure 23 is shown as Figure 23 The abscissa represents the chromatic aberration, and the ordinate represents the field angle. The maximum field chromatic aberration is less than 135 um, the field chromatic aberration is small, and the imaging is clear and accurate.

[0125] Example 5

[0126] Refer to Figure 24 , in Example 5, the total length of the entire optical module is about 18.10 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 20.10 mm, and the field angle is 100 deg. The central thickness CT1 of the first lens is 6.68 mm, the central thickness CT2 of the second lens is 5.48 mm, and the air gap GAP between the first lens and the second lens is 2.45 mm. At this time:

[0127] FG / (CT1 + GAP) + FG / (CT2 + GAP) = 4.74。

[0128] The surfaces of the first lens and the second lens are both even aspherical surfaces. For the radius of curvature and other parameters of the first lens and the second lens, see Table 5 below. Among them, A2 - A12 are the even aspherical coefficients corresponding respectively, which are the quadratic term to the twelfth term. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 9.72.

[0129] Table 5

[0130]

[0131] In Example 5, the system parameters and performance are as follows:

[0132] Refer to Figure 25 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 7 microns, and the imaging is clear.

[0133] Refer to Figure 26 , Figure 26 The abscissa in

[0134] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 27 The abscissa in the left figure represents the field curvature. Figure 27 The abscissa in the right figure represents the distortion. It can be seen that the maximum field curvature does not exceed 0.5 mm, and the distortion is not greater than 30%, and the field curvature and distortion are small.

[0135] Chromatic aberration reflects the differences in the imaging positions of light with different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 5 Figure 28 as shown in Figure 28 The abscissa represents the chromatic aberration, and the ordinate represents the field angle. The maximum field chromatic aberration is less than 140 um, and the field chromatic aberration is small, and the imaging is clear and accurate.

[0136] Example 6

[0137] Refer to Figure 29 , in Example 6, the total length of the entire optical module is about 18.47 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 22.89 mm, and the field angle is 100 deg. The central thickness CT1 of the first lens is 9.56 mm, the central thickness CT2 of the second lens is 3.79 mm, and the air gap GAP between the first lens and the second lens is 2.01 mm. At this time:

[0138] FG / (CT1 + GAP) + FG / (CT2 + GAP) = 5.93.

[0139] The surfaces of the first lens and the second lens are both even aspherical surfaces. For the curvature radii and other parameters of the first lens and the second lens, see Table 6 below. Among them, A2 - A12 are the even aspherical coefficients corresponding respectively, which are from the quadratic term to the twelfth term. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 9.23.

[0140] Table 6

[0141]

[0142] In Example 6, the system parameters and performance are as follows:

[0143] Refer to Figure 30 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 5 microns, and the imaging is clear.

[0144] Refer to Figure 31 , Figure 31 In

[0145] The field curvature and distortion reflect the differences in the positions of the clear imaging planes in different fields of view. Figure 32 In the left figure, the abscissa represents the field curvature. Figure 32 In the right figure, the abscissa represents the distortion. It can be seen that the maximum field curvature does not exceed 0.2 mm, and the distortion is not greater than 30%. The field curvature and distortion are small.

[0146] Chromatic aberration reflects the differences in the imaging positions of light with different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Example 6 Figure 33 as shown in Figure 33 the abscissa represents the chromatic aberration, and the ordinate represents the field angle. The maximum field chromatic aberration is less than 150 um, and the field chromatic aberration is small, and the imaging is clear and accurate.

[0147] Example 7

[0148] Refer to Figure 34, in Embodiment 7, the total length of the entire optical module is approximately 24.08 mm, and the material is APEL (cycloolefin copolymer). The overall optical focal length FG is 27.02 mm. The central thickness CT1 of the first lens is 6.95 mm, the central thickness CT2 of the second lens is 5.74 mm, and the air gap GAP between the first lens and the second lens is 3.55 mm. At this time:

[0149] FG / (CT1 + GAP) + FG / (CT2 + GAP) = 5.48.

[0150] The surfaces of both the first lens and the second lens are even aspheres. For the curvature radii and other parameters of the first lens and the second lens, see Table 7 below. Among them, A2 - A12 are the even aspheric coefficients corresponding to the second to the twelfth terms respectively. At this time: (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) = 11.06.

[0151] Table 7

[0152]

[0153] In Embodiment 7, the system parameters and performance are as follows:

[0154] Referring to Figure 35 , in the entire field of view, the maximum value of the image points in the spot diagram of the optical module (see the value of RMS radius in the figure) is less than 11 microns, and the imaging is clear.

[0155] Referring to Figure 36 , Figure 36 , the abscissa in

[0156] represents the spatial frequency. It can be seen that at 40 line pairs per millimeter, the MTF (modulation transfer function) value is higher than 0.4, indicating good resolution of the model. Figure 37 In the left figure, the abscissa represents the field curvature, Figure 7 and in the right figure, the abscissa represents the distortion. It can be seen that the maximum field curvature does not exceed 0.4 mm, and the distortion is not greater than 30%, indicating that the field curvature and distortion are small.

[0157] Chromatic aberration reflects the difference in the imaging positions of light of different wavelengths in different fields of view on the image plane. The chromatic aberration of the system in Embodiment 7 Figure 38 is shown as Figure 38 , where the abscissa represents the chromatic aberration and the ordinate represents the field angle. The maximum field chromatic aberration is less than 220 μm, indicating small field chromatic aberration and clear and accurate imaging.

[0158] In the above-described Embodiment 1 to Embodiment 4, specific embodiments of taking endpoint values are given, and Embodiment 5 to Embodiment 7 give specific embodiments of taking intermediate values. It can be seen from the optical performance diagrams of each embodiment that when the value range of FG / (CT1 + GAP) + FG / (CT2 + GAP) is 4.5 to 9 (excluding the endpoint values), and the value range of (RL1S1 + RL1S2) / (RL1S1 - RL1S2) + (RL2S1 + RL2S2) / (RL2S1 - RL2S2) is 8 to 14 (excluding the endpoint values), the optical performance parameters of each embodiment meet the requirements, which can not only play a role in reducing the volume of the optical module, but also ensure clear imaging.

[0159] According to another aspect of the present invention, the present invention further provides a head-mounted display device, and the head-mounted display device includes the above-described optical module. Since the head-mounted display device includes all the technical solutions of all the above embodiments of the optical module, therefore, it has at least all the beneficial effects brought by all the above technical solutions, and will not be elaborated herein one by one.

[0160] In some embodiments, the head-mounted display device is any one of a virtual display device, an augmented reality device, or a mixed reality device.

[0161] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and do not limit the patent scope of the present invention; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: under the technical concept of the present invention, it is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacement on some or all of the technical features; or directly / indirectly apply them to other related technical fields, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of each embodiment of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. An optical module, characterized in that: including a first optical element and a second optical element; The first optical element includes a first lens and a beam splitter; The second optical element includes a second lens, a polarization reflector and a phase retarder; The beam splitter, the first lens, the phase retarder, the polarization reflector and the second lens are arranged in sequence along the same optical axis; The side of the first optical element away from the second optical element is the screen side, and the side of the second optical element away from the first optical element is the human eye side. The curvature radius of the S1 surface of the first lens located on the screen side is defined as R L1S1 The curvature radius of the S2 surface of the first lens located on the human eye side is R L1S2 The curvature radius of the S1 surface of the second lens located on the screen side is R L2S1 The curvature radius of the S2 surface of the second lens located on the human eye side is R L2S2 , then: 。 2. The optical module according to claim 1, characterized in that: Define the overall optical focal length of the optical module as FG, the center thickness of the first lens as CT1, the center thickness of the second lens as CT2, and the air gap between the first lens and the second lens as GAP, then: 。 3. The optical module according to claim 1, characterized in that: The first lens and the second lens have a convex surface at one side facing the screen at the near optical axis, and a concave surface at one side facing the human eye at the near optical axis.

4. The optical module according to claim 1, characterized in that: The optical module further includes an image display unit, and the image display unit is arranged on the screen side.

5. The optical module according to claim 4, characterized in that: The optical module further includes a first quarter glass slide, and the first quarter glass slide is arranged on a side of the image display unit facing the beam splitter.

6. The optical module according to any one of claims 1 to 5, characterized in that: The beam splitter comprises a semi-transparent and semi-reflective film, and the semi-transparent and semi-reflective film is attached to a side of the first lens away from the second lens.

7. The optical module according to any one of claims 1 to 5, characterized in that: The phase retarder and the polarization reflector are stacked, and the polarization reflector is arranged on the surface of the second lens.

8. The optical module according to claim 5, characterized in that: The polarizing reflector comprises a polarizing reflective plate, and the phase retarder comprises a second quarter glass plate. The polarizing reflective plate is attached to a side of the second lens facing the first lens, and the second quarter glass plate is attached to a side of the polarizing reflective plate facing away from the second lens.

9. A head mounted display device, characterized in that: The head mounted display device comprises the optical module according to any one of claims 1 to 8.

10. The head mounted display device according to claim 9, characterized in that: The head mounted display device is any one of a virtual display device, an augmented reality device or a mixed reality device.

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