CN115421302A

CN115421302A - Optical module and head-mounted display equipment

Info

Publication number: CN115421302A
Application number: CN202210909852.7A
Authority: CN
Inventors: 史柴源
Original assignee: Goertek Optical Technology Co Ltd
Current assignee: Goertek Optical Technology Co Ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2022-12-02

Abstract

The application discloses an optical module and a head-mounted display device; the optical module comprises a first lens module, a second lens module and a transparent screen, wherein the transparent screen is positioned between the first lens module and the second lens module; the first lens module is configured to be operable to transmit a first light ray, the first light ray being a real-world light ray; the transparent screen is configured to be operable to transmit the first light and emit a second light; the first lens module comprises at least one lens, the at least one lens comprises a first lens, and the focal length of the first lens is f ₁ ，f ₁ Satisfies the following conditions: f. of ₁ < -1000mm, or f ₁ Is greater than 1000mm. The optical module of this application can enlarge optical module's virtual angle of vision and real angle of vision, can make the user obtain the high sense of immersing, can also promote imaging quality.

Description

Optical module and head-mounted display equipment

Technical Field

The application belongs to the technical field of optical display, more specifically, the application relates to an optical module and a head-mounted display device.

Background

In recent years, augmented Reality (AR) technology has been applied to head-mounted display devices and is rapidly developed. The effect that the optical module shows will directly determine the quality of AR head mounted display device. With the development of AR head-mounted display devices, the requirements on the AR head-mounted display devices are also higher and higher, and especially, higher requirements on the imaging quality and the immersion feeling of the devices are made. However, the existing AR head-mounted display device still has the problems of low imaging quality and poor immersion when used by a user, which will affect the development and popularization of the AR device.

Disclosure of Invention

An object of the embodiment of the present application is to provide a new technical scheme of an optical module and a head-mounted display device.

According to a first aspect of embodiments of the present application, there is provided an optical module comprising a first lens module, a second lens module, and a transparent screen, wherein the transparent screen is located between the first lens module and the second lens module;

the first lens module is configured to transmit a first light ray, wherein the first light ray is a real-world light ray;

the transparent screen is configured to transmit the first light and is capable of emitting second light by itself;

the first lens module comprises at least one lens, the at least one lens comprising a first lens having a focal length f ₁ ，f ₁ Satisfies the following conditions: f. of ₁ < -1000mm, or f ₁ ＞1000mm。

Optionally, the focal length f of the optical module is greater than 100mm.

Optionally, the virtual view field angle and the real view field angle of the optical module are both greater than 90 degrees.

Optionally, an absolute value of a radius of curvature of the first lens is greater than 200mm.

Optionally, the focal power of the first lens is-0.01 to 0.01.

Optionally, the center thickness of the first lens is T1, and T1 satisfies: 0.5mm T1 was constructed of 8mm.

Optionally, the second lens module comprises a lens group comprising at least a second lens.

Optionally, the second lens has an optical power of 0 to 0.01.

Optionally, the second lens module further includes a light splitting element, a phase retarder, and a polarization reflecting element, the light splitting element is located on one side of the second lens close to the transparent screen, the phase retarder and the polarization reflecting element are located on one side of the second lens far away from the transparent screen, and the phase retarder is located between the light splitting element and the polarization reflecting element.

Optionally, the second lens module further comprises a polarizing element located on a side of the polarization reflecting element facing away from the phase retarder.

Optionally, the light splitting element is disposed on a surface of the second lens close to the transparent screen, the phase retarder, the polarization reflecting element and the polarization element are sequentially stacked to form a stacked element, and the stacked element is disposed on a surface of the second lens far from the transparent screen.

Optionally, the second lens has a center thickness T2, and T2 satisfies: t2 is more than or equal to 3mm and less than or equal to 10mm.

According to a second aspect of embodiments of the present application, there is also provided a head mounted display device, including:

a housing; and

such as the optical module described above.

According to the optical module, the transparent screen is matched in the light path, so that the first light rays can be transmitted, the second light rays can be emitted, the larger virtual view field angle and the larger real view field angle can be realized, and the higher immersion sense can be realized; the first lens module is introduced to one side of the transparent screen, which deviates from the second lens module, and the first lens module can be used for correcting aberration introduced when the second lens module processes the second light, so that the imaging quality can be improved, and a user can obtain good visual experience.

Further features of the present application and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which is to be read in connection with the accompanying drawings.

Drawings

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

Fig. 1 is a schematic structural diagram of an optical module provided in embodiment 1 of the present application;

fig. 2 is a second schematic structural diagram of an optical module according to embodiment 1 of the present application;

fig. 3 is a third schematic structural diagram of an optical module according to embodiment 1 of the present application;

fig. 4 is a MTF graph of a virtual optical path of an optical module according to embodiment 1 of the present application;

fig. 5 is a dot arrangement diagram of a virtual optical path of an optical module provided in embodiment 1 of the present application;

fig. 6 is a field curvature and distortion diagram of a virtual optical path of the optical module provided in embodiment 1 of the present application;

fig. 7 is a vertical axis chromatic aberration diagram of a virtual optical path of the optical module provided in embodiment 1 of the present application;

fig. 8 is an MTF graph of a real optical path of an optical module provided in embodiment 1 of the present application;

fig. 9 is a point diagram of a real optical path of the optical module provided in embodiment 1 of the present application;

fig. 10 is a field curvature and distortion diagram of a real optical path of the optical module provided in embodiment 1 of the present application;

fig. 11 is a vertical axis chromatic aberration diagram of a real optical path of the optical module provided in embodiment 1 of the present application;

fig. 12 is a schematic structural diagram of an optical module according to embodiment 2 of the present application;

fig. 13 is a MTF graph of a virtual optical path of an optical module according to embodiment 2 of the present application;

fig. 14 is a dot-column diagram of a virtual optical path of the optical module provided in embodiment 2 of the present application;

fig. 15 is a field curvature and distortion diagram of a virtual optical path of an optical module provided in embodiment 2 of the present application;

fig. 16 is a vertical axis chromatic aberration diagram of a virtual optical path of the optical module according to embodiment 2 of the present application;

fig. 17 is an MTF graph of a real optical path of an optical module provided in embodiment 2 of the present application;

fig. 18 is a point diagram of a real optical path of an optical module provided in embodiment 2 of the present application;

fig. 19 is a field curvature and distortion diagram of a real optical path of the optical module provided in embodiment 2 of the present application;

fig. 20 is a vertical axis chromatic aberration diagram of a real optical path of the optical module provided in embodiment 2 of the present application;

fig. 21 is a schematic structural view of an optical module according to embodiment 3 of the present application;

fig. 22 is an MTF graph of a virtual optical path of an optical module according to embodiment 3 of the present application;

fig. 23 is a schematic diagram of a virtual optical path of an optical module according to embodiment 3 of the present application;

FIG. 24 is a graph showing the field curvature and distortion of a virtual optical path of an optical module according to example 3 of the present application;

fig. 25 is a vertical axis chromatic aberration diagram of a virtual optical path of an optical module provided in embodiment 3 of the present application;

fig. 26 is a MTF graph of a real optical path of an optical module provided in embodiment 3 of the present application;

fig. 27 is a dot-column diagram of a real optical path of the optical module provided in embodiment 3 of the present application;

fig. 28 is a field curvature and distortion diagram of a real optical path of the optical module provided in embodiment 3 of the present application;

fig. 29 is a vertical axis chromatic aberration diagram of a real optical path of the optical module provided in embodiment 3 of the present application.

Description of reference numerals:

10. a first lens module; 11. a first lens; 111. a first surface; 112. a second surface; 20. a second lens module; 21. a second lens; 211. a third surface; 212. a fourth surface; 30. a transparent screen; 40. a light splitting element; 50. a phase retarder; 60. a polarizing reflective element; 70. a polarizing element; 80. an antireflection film; 01. the human eye; 02. a first light ray; 03. the second light ray.

Detailed Description

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

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

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

According to an aspect of the embodiments of the present application, an optical module is provided, which is suitable for being applied to a Head Mounted Display (HMD), such as an augmented reality HMD, including AR glasses or an AR helmet, and the like, and the embodiments of the present application are not particularly limited thereto.

The embodiment of the present application provides an optical module, as shown in fig. 1 and 2, the optical module includes: a first lens module 10, a second lens module 20, and a transparent screen 30, wherein the transparent screen 30 is located between the first lens module 10 and the second lens module 20;

the first lens module 10 is configured to transmit a first light ray 02, wherein the first light ray 02 is a real-world light ray; the transparent screen 30 is configured for transmitting the first light rays 02 and is itself capable of emitting second light rays 03;

wherein the first lens module 10 comprises at least one lens, the at least one lens comprises a first lens 11, and the focal length of the first lens 11 is f ₁ ，f ₁ Satisfies the following conditions: f. of ₁ < -1000mm, or f ₁ ＞1000mm。

The optical module of this application embodiment, as shown in fig. 1, it includes virtual reality light path part and corrects the light path part. The virtual reality optical path portion includes a second lens module 20 and a transparent screen 30. The corrective optical path portion comprises a first lens module 10 introduced on the side of the transparent screen 30 facing away from the second lens module 20. The introduction of the first lens module 10 can be used to correct aberrations introduced when the second lens module 20 processes the second light emitted through the transparent screen 30, which is advantageous in improving the imaging quality.

The optical module of this application embodiment, transparent screen 30 has wherein been collocated, and this near-to-eye augmented reality display module group that does benefit to and realizes big FOV can realize great virtual visual field angle and reality visual field angle to can make optical module group realize high sense of immersing.

The second lens module 20 is configured to process a second light ray 03 (a virtual imaging light ray) emitted from the transparent screen 30, so as to form a virtual imaging propagation path. One lens is included in the second lens module 20, but not limited thereto, and may be selectively arranged as one, two or more lenses according to specific needs.

For example, the second lens module 20 may be a direct-transmission optical structure including one or more lenses, wherein the lens surface type may be an aspheric surface, a fresnel surface, a free-form surface, or the like.

For another example, the second lens module 20 may have a folded optical structure. The folded optical path structure is beneficial to reducing the overall size and weight of the optical module, which is not limited in the embodiment of the present application.

The number of lenses included in the first lens module 10 can also be selectively set to one, two or more according to specific situations, which is not limited in the embodiment of the present application. However, in consideration of the problem that the size of the optical module is not easily made excessively large, in the optical module of the embodiment of the present application, one lens, that is, the first lens 11 shown in fig. 2, may be selectively provided in the first lens module 10. So, do benefit to the size and the weight that make optical module less, also can guarantee good formation of image quality simultaneously.

In the embodiment of the present application, the first lens module 10 is introduced into the optical module as a corrective element and is disposed in the real optical path,for example, a first lens 11 is provided in the first lens module 10, and the focal length f of the first lens 11 is adjusted ₁ Is designed in that f ₁ Satisfies the following conditions: f. of ₁ < -1000mm, or f ₁ Is greater than 1000mm. In the whole optical module, the focal length range of the first lens 11 is designed to correct the optical aberration introduced by the virtual optical path portion, and meanwhile, the user's visibility can be corrected by adjusting the focal length of the optical module.

To correct the user's diopter by adjusting the focal length of the optical module, specifically, when the optical module of the embodiment of the present application is applied, the focal length f of the first lens 11 is adjusted ₁ The focusing of optical module or the position of the virtual image that the adjustment formed can be realized, so just realized the adjustment to optical module diopter, and then make optical module can match the user group of different diopter degrees, the user like near-sighted can carry out visual experience under the condition of not wearing glasses.

In the optical module of the embodiment of the present application, as shown in fig. 2, the light propagation path is: the first light 02 can enter human eyes 01 through the first lens module 10, the transparent screen 30 and the second lens module 20, so that a real light path is formed; the second light 03 can be emitted through the transparent screen 30 and then emitted after passing through the second lens module 20, so that a virtual light path is formed, the two light paths are matched with each other to be injected into the human eye 01, and the imaging quality can be improved.

According to the optical module of the embodiment of the application, the transparent screen 30 is matched in the light path, so that the optical module can transmit first light (namely light of the real world) and can also transmit second light (virtual imaging light), and the optical module is beneficial to realizing a larger virtual view field angle and a larger real view field angle, thereby realizing higher immersion; the first lens module 10 is introduced at a side of the transparent screen 30 away from the second lens module 20, and the first lens module 10 can be used for correcting aberration introduced when the second lens module 20 processes the second light ray, so that the imaging quality can be improved, and a user can obtain good visual experience.

In addition, the optical module of the embodiment of the application has better wearing experience performance for people with different visual degrees,wherein the focal length f of the first lens 11 is adjusted ₁ The optical module can be used by users with different visual degrees without wearing glasses. Meanwhile, the optical module is simple in structure, low in manufacturing cost and high in yield.

In some examples of the present application, the focal length of the optical module is greater than 100mm.

In the embodiment of the application, the virtual view field angle and the real view field angle of the optical module are both greater than 90 degrees.

In the embodiment of this application, the focus of optical module is for being greater than 100mm, and simultaneously, the virtual visual field angle of cooperation and the real visual field angle are greater than 90, and the user can watch clear formation of image, and obtains stronger sense of immersing, can promote user's visual experience.

In some examples of the present application, as shown in fig. 1 and 2, in the optical module, an absolute value of a radius of curvature of the first lens 11 is greater than 200mm.

It should be noted that, in the optical module according to the embodiment of the present application, the first lens module 10 may include a first lens 11, and the focal length range of the first lens 11 may be adjusted by adjusting the curvature radius of the first lens 11, for example, the focal length f of the first lens 11 is adjusted ₁ The adjustment is to satisfy: f. of ₁ < -1000mm, or f ₁ Is greater than 1000mm. Thereby adjusting the focal length of the whole optical module. The clear and complete image can be observed by different users.

In the embodiment of the present application, as shown in fig. 2, by introducing the first lens module 10 at a side of the transparent screen 30 facing away from the second lens module 20, the first lens module 10 and the transparent screen 30 can transmit the light rays displaying the world, i.e., the first light rays 02. First lens module 10 can regard as correcting element in the light path, and through adjusting wherein first lens 11's curvature radius, can select more suitable focus's first lens 11 to add to optical module, can be better carry out accurate correction to the aberration that virtual light path introduced, can promote optical module's imaging quality, so realized the function that augmented reality shows. Simultaneously, compare in current AR optical module, can increase virtual visual field angle and reality visual field angle, the user can obtain high sense of immersing.

According to the optical module of the embodiment of the present application, as shown in FIG. 2, when the focal length f of the first lens 11 is larger ₁ Is f ₁ < -1000mm or f ₁ The curvature radius of the first lens 11 is larger than 200mm, and when at least one of the focal lengths of the optical module is 100, the virtual view field angle and the real view field angle of the optical module can reach 100 degrees or even be larger, so that a user can view clear imaging under a large view field. The conventional AR optical module cannot achieve such a large viewing angle, and further cannot enable a user to view a clear image under such a large viewing angle.

In some examples of the present application, in the optical module, the first lens 11 has an optical power of-0.01 to 0.01.

In the embodiment of the present application, by adjusting the power of the first lens 11, the focal length f of the first lens 11 can be adjusted ₁ The range of (1). For example, when the focal power of the first lens 11 is-0.01 to 0.01, the focal length f of the first lens 11 ₁ Comprises the following steps: f. of ₁ < -1000mm, or f ₁ Is greater than 1000mm. Therefore, the requirements of correcting the aberration of the optical module and adjusting the visibility of the optical module can be met. Therefore, the optical module has good immersion and high imaging quality, and can be suitable for groups with different degrees of vision.

In some examples of the present application, the second lens module 20 includes a lens group including at least a second lens 21.

Optionally, the focal power of the second lens 21 is 0 to 0.01.

In the embodiment of the present application, when the first lens module 10 includes the first lens 11, and the second lens module 20 includes the second lens 21, the focal powers of the first lens 11 and the second lens 21 are adjusted by design, for example, the focal power of the first lens 11 ranges from-0.01 to 0.01, and the focal power of the second lens 21 ranges from 0 to 0.01, so that the focal powers of the parts in the optical module are distributed uniformly, the total focal power of the optical module can be adjusted reasonably, and the field angle of the optical module can be adjusted accordingly. The virtual visual field angle and the real visual field angle of the optical module of the embodiment of the application can be well expanded, for example, the virtual visual field angle and the real visual field angle can reach more than 90 degrees, the immersion experience feeling of the optical module is very important, and the viewing experience of a user is improved.

In some examples of the present application, the second lens module 20 further includes a beam splitting element 40, a phase retarder 50, and a polarization reflection element 60, the beam splitting element 40 is located on a side of the second lens 21 close to the transparent screen 30, the phase retarder 50 and the polarization reflection element 60 are located on a side of the second lens 21 far from the transparent screen 30, and the phase retarder 50 is located between the beam splitting element 40 and the polarization reflection element 60.

It should be noted that, in the optical module according to the embodiment of the present application, the second lens module 20 may be a folded optical path structure of a single lens, which is favorable for reducing the volume and weight of the optical module.

The light splitting element 40 allows a part of the light to pass through and a part of the light to reflect.

The light splitting element 40 may be, for example, a transflective film. The reflectivity and transmittance of the light splitting element 40 in the embodiment of the present application are not limited, and can be adjusted according to specific situations.

Wherein the phase retarder 50 may be used to change the polarization state of light in the folded optical path structure. For example, it is possible to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

The phase retarder 50 is, for example, a quarter-wave plate.

The polarization reflection element 60 can be used for transmitting P-polarized light and reflecting S-polarized light; alternatively, the polarizing reflective element 60 may be used to transmit S-polarized light and reflect P-polarized light.

The polarizing reflection element 60 is, for example, a polarizing reflection film.

Alternatively, the beam splitting element 40 and the phase retarder 50 may be attached together to form a composite optical film. Of course, the beam splitting element 40 and the phase retarder 50 may be spaced apart.

That is, the light splitting element 40 and the phase retarder 50 may be disposed on the same side of the second lens 21. Of course, the spectroscopic element 40 and the phase retarder 50 may be provided separately on both sides of the second lens 21, and in this case, as shown in fig. 2, the spectroscopic element 40 and the phase retarder 50 may be separated by the second lens 21. In the embodiment of the present application, there is no particular limitation on the specific arrangement manner of the optical splitting element 40 and the phase retarder 50 in the optical path structure.

Alternatively, the phase retarder 50 and the polarization reflecting element 60 may be attached together. Of course, the phase retarder 50 and the polarization reflective element 60 may be disposed at intervals. The phase retarder 50 needs to be located between the light splitting element 40 and the polarization reflecting element 60. The retarder 50, in cooperation with the polarization reflective element 60, may be used to resolve and transmit light.

In the present application, the phase retarder 50 and the polarization reflective element 60 may be disposed on the same side of the second lens 21. Of course, the phase retarder 50 and the polarization reflection element 60 may be disposed on both sides of the second lens 21, and the phase retarder 50 and the polarization reflection element 60 may be separated by the second lens 21. It should be noted that, in the embodiment of the present application, there is no particular limitation on the specific arrangement manner of the phase retarder 50 and the polarization reflection element 60 in the optical path structure.

Of course, the second lens module 20 may also be a single-lens aspheric lens, a single-lens fresnel surface lens, and the like, which is not limited in the embodiment of the present application.

Optionally, as shown in fig. 2 and 3, the second lens module 20 further includes a polarization element 70, and the polarization element 70 is located on a side of the polarization reflection element 60 facing away from the phase retarder 50.

In the embodiment of the present application, the second lens module 20 is a folded optical path, and may further include a polarization element 70 in the optical module in the optical path, and the polarization element 70 may transmit P polarized light, so as to reduce ghost and stray light, and facilitate improvement of imaging quality.

The polarizing element 70 and the polarization reflecting element 60 can be attached together. Of course, the polarizing element 70 and the polarization reflecting element 60 may be disposed at an interval.

In some examples of the present application, as shown in fig. 2 and 3, the beam splitting element 40 is disposed on a surface of the second lens 21 close to the transparent screen 30, the retarder 50, the polarization reflecting element 60, and the polarization element 70 are sequentially stacked to form a stacked element, and the stacked element is disposed on a surface of the second lens 21 far from the transparent screen 30.

The second lens 21 includes a third surface 211 and a fourth surface 212, the third surface 211 is close to the transparent screen 30, and the fourth surface 212 is far from the transparent screen 30.

The light splitting element 40 is, for example, a transflective film. The phase retarder 50 is, for example, a quarter-wave plate. The polarizing reflection element 60 is, for example, a polarizing reflection film (P-light transmitting and S-light reflecting). The polarizing element 70 is, for example, a polarizing film (P-ray transmitting).

Optionally, the third surface 211 is aspheric, and the fourth surface 212 is planar or aspheric.

Optionally, a semi-reflective and semi-transparent film may be formed on the third surface 211 by means of plating.

Optionally, as shown in fig. 3, the quarter-wave plate, the polarization reflective film and the polarization film are stacked to form a stacked element, and the stacked element is attached to the fourth surface 212 of the second lens 21 through an optical adhesive, wherein the quarter-wave plate is directly bonded to the fourth surface 212, and the polarization reflective film is located between the quarter-wave plate and the polarization film.

In addition, an antireflection film 80 may be attached to the side of the polarizing film facing away from the polarizing reflective film, as shown in fig. 3. The anti-reflection film can be used for increasing the transmitted light and reducing the reflected light.

That is, the second lens 21 supports the polarizing element 70, the polarization reflecting element 60, the phase retarder 50, and the spectroscopic element 40. The polarization element 70 can transmit P-polarized light, thereby reducing ghost and stray light and improving imaging quality.

More preferably, the fourth surface 212 may be designed to be a plane, which is beneficial for mounting the above-mentioned laminated element thereon, so as to reduce the mounting difficulty.

It should be noted that, in general, the surface of the lens to which the optical film is attached may be designed to be flat. The mode of adopting plane pad pasting in the light path can reduce the pad pasting degree of difficulty of blooming. Of course, a film with a curved surface/a cylindrical surface or the like may also be used, which is not particularly limited in the embodiment of the present application.

In addition, the phase retarder 50 and the light splitting element 40 may also be attached to the third surface 211 of the second lens 21, and the polarization reflecting element 60 and the polarization element 70 may also be attached to the fourth surface 212 of the second lens 21, which is not limited in the embodiment of the present application.

In the optical module of the embodiment of the present application, the first lens module 10 may be configured to transmit light of a real world, such as the first light 02 shown in fig. 2, and the first lens module 10 may include a first lens 11, such as the first lens 11 shown in fig. 2, where the first lens 11 includes two optical surfaces, i.e., a first surface 111 and a second surface 112, respectively, where the first surface 111 faces away from the transparent screen 30, and the second surface 112 is close to the transparent screen 30.

Alternatively, the first surface 111 and the second surface 112 may be planar or aspherical.

It should be noted that the first surface 111 and the second surface 112 may have the same or different surface types, and this is not limited in this embodiment of the application. Alternatively, the antireflection film may be attached to both the first surface 111 and the second surface 112. The anti-reflection film can be used for increasing the transmitted light and reducing the reflected light.

In some examples of the present application, the first lens 11 has a center thickness T1, and T1 satisfies: 0.5 mm-T1-8 mm; the center thickness of the second lens 21 is T2, and T2 satisfies: t2 is more than or equal to 3mm and less than or equal to 10mm. The first lens 11 and the second lens 21 are small in size, which is beneficial to reducing the weight of the optical module. The comfort can be improved when the user wears a product containing the optical module.

The optical module provided by the embodiment of the application has the advantages that the central thickness of the first lens 11 ranges from 0.5mm to T1 mm to 8mm, and the optical power of the first lens can be selected from-0.01; the central thickness of the second lens 21 is in the range of 3mm to 10mm, T2 and the focal power of the second lens is in the range of 0-0.01. Therefore, the size of the optical module can not be increased, the optical module is light and thin, and the imaging quality can be ensured.

Wherein the refractive index of the first lens 11 and the second lens 21 is n, and n satisfies: n is more than 1.45 and less than 1.8; the first lens 11 and the second lens 21 have an abbe number v, and v satisfies: v is more than 20 and less than 75. This may improve the imaging quality of the lens.

For example, the refractive index of the first lens 11 is 1.64 and the abbe number is 23. The refractive index of the second lens 21 is 1.55 and the abbe number is 56. The refractive index and the dispersion coefficient of the two lenses are adjusted to be matched, so that the imaging quality of the optical module can be improved.

It should be noted that, the number of the lenses in the optical module provided by the present application may not be specifically limited, and the number of the lenses may be one, two, or more than or equal to three. The imaging quality can be improved as the number of lenses increases. Among them, it is preferable to provide two lenses in the optical path. Therefore, the optical module can be thinned while the imaging quality of the optical module is ensured.

Optionally, the transparent screen 30 has a light emitting surface, and a screen protection sheet may be attached to the light emitting surface of the transparent screen 30. The transparent screen 30 may for example emit circularly polarized light.

As shown in fig. 2, the optical module according to the embodiment of the present disclosure has the following light propagation paths:

the real world light (first light 02) can be projected into the human eye 01 through the first lens 11, the transparent screen 30 and the second lens 21, which forms a path of real light. The transparent screen 30 emits circularly polarized light (second light 03), which is transmitted through the third surface 211, and then is converted into linearly polarized light (S light) by the light splitting element 40 of the fourth surface 212, and then is reflected by the polarization reflecting element 60, and then is converted into circularly polarized light (P light) by the light splitting element 40, and after being transmitted through the fourth surface 212, the circularly polarized light is incident on the human eye 01, so that a virtual light path is formed.

The optical module according to the embodiment of the present application will be described below with reference to three embodiments.

Example 1

The optical module of embodiment 1, as shown in fig. 2 and fig. 3, includes a first lens 11, a second lens 21, and a transparent screen 30, where the transparent screen 30 is located between the first lens 11 and the second lens 21, the first lens 11 is configured to transmit a first light 02, and the first light 02 is a real-world light; the transparent screen 30 is configured for transmitting the first light rays 02 and is itself capable of emitting second light rays 03;

the optical module further comprises a light splitting element 40, a phase retarder 50 and a polarization reflecting element 60, wherein the light splitting element 40 is attached to a third surface 211 of the second lens 21, the phase retarder 50, the polarization reflecting element 60 and the polarization element 70 are stacked and attached to a fourth surface 212 of the second lens 21, and the phase retarder 50 is located between the light splitting element 40 and the polarization reflecting element 60. Wherein the focal length f of the first lens 11 ₁ Is-1970 mm, the focal length f of the second lens 21 ₂ Is 155mm.

Table 1 shows the optical parameters of the optical module;

TABLE 1

The optical performance of the optical module of embodiment 1 of the present application is as follows:

fig. 4 to 7 are aberration characterization diagrams of the virtual optical path in embodiment 1. Fig. 8 to 11 are aberration characterization diagrams of the real optical path in embodiment 1.

Fig. 4 and 8 are MTF graphs, i.e., modulation transfer function graphs, of the optical module of example 1, and the imaging clarity of the optical module is characterized by the contrast of black and white line pairs. In embodiment 1, the virtual optical path MTF is >0.3 at 15lp/mm as shown in FIG. 4, and the real optical path MTF is >0.25 at 15lp/mm as shown in FIG. 8.

Fig. 5 and 9 are each a dot arrangement diagram of the optical module of embodiment 1. The point alignment chart is that after a plurality of light rays emitted by one point pass through the optical system, intersection points of the light rays and the image plane are not concentrated on the same point any more due to aberration, and a diffusion pattern which is dispersed in a certain range is formed and is used for evaluating the imaging quality of the projection optical module. In embodiment 1, as shown in fig. 5, the maximum value of the image point in the point array diagram of the virtual optical path is less than 53 μm; as shown in FIG. 9, the maximum value of the image point in the point alignment image in the real light path is less than 19 μm.

Fig. 6 and 10 are both field curvature and distortion diagrams of the optical module of example 1. In embodiment 1, as shown in fig. 6, the maximum value of the field curvature of the virtual optical path is less than 1.6mm, and as shown in fig. 10, the maximum value of the field curvature of the real optical path is less than 0.5mm. Distortion reflects the deformation condition of the image, in example 1, please continue as shown in fig. 6, the maximum value of the distortion of the virtual optical path occurs in the field of view 1, and the maximum value is less than 35% (absolute value), please continue as shown in fig. 10, the maximum value of the distortion of the real optical path occurs in the field of view 0.8, and the maximum value is less than 1.2% (absolute value).

Fig. 7 and 11 are vertical axis chromatograms of the optical module of embodiment 1, which are also called as magnification chromatograms, and mainly refer to a difference between a multiple-color principal ray of an object side and a focal position of blue light and red light on an image plane when the principal ray is emitted from an image side due to chromatic dispersion of a refraction system. In example 1: as shown in fig. 7, the maximum dispersion of the virtual optical path is 1 field position of the system, and the maximum chromatic aberration value is less than 210 μm; as shown in fig. 11, the maximum dispersion of the real optical path is 1 field position of the system, and the maximum chromatic aberration value is less than 88 μm.

Example 2

Embodiment 2 shows an optical module, which is different from embodiment 1 in that, as shown in fig. 12:

focal length f of the first lens 11 ₁ 6780mm, the focal length f of the second lens 21 ₂ Is 156mm. Table 2 shows the optical parameters of the optical module;

TABLE 2

The optical performance of the optical module of embodiment 2 of the present application is as follows:

fig. 13 to 16 are aberration characterization diagrams of a virtual optical path in embodiment 2, and fig. 17 to 20 are aberration characterization diagrams of a real optical path in embodiment 2.

Fig. 13 and 17 are MTF graphs of the optical module of example 2. In embodiment 2, as shown in fig. 13, the virtual optical path MTF is >0.3 at 15 lp/mm; as shown in FIG. 17, the real path MTF is >0.35 at 15 lp/mm.

Fig. 14 and 18 are each a dot array diagram of the optical module of example 2. In embodiment 2, as shown in fig. 14, the maximum value of the image point in the point array diagram of the virtual optical path is less than 53 μm; as shown in fig. 18, the maximum value of the image point in the point array image in the real optical path is less than 22 μm.

Fig. 15 and 19 are both field curvature and distortion plots for the optical module of example 2. In example 2: as shown in fig. 15, the maximum value of the virtual optical path curvature of field is less than 1.8mm, and as shown in fig. 19, the maximum value of the real optical path curvature of field is less than 1mm. Distortion reflects the deformation of the image, in example 2, please continue as shown in fig. 15, the maximum value of the distortion of the virtual optical path occurs in 1 view field, and the maximum value is less than 35% (absolute value), please continue as shown in fig. 19, the maximum value of the distortion of the real optical path occurs in 0.5 view field, and the maximum value is less than 0.9% (absolute value).

Fig. 16 and 20 are vertical axis chromatic aberration diagrams, also called as chromatic aberration of magnification, of the optical module of embodiment 2. In example 2: as shown in fig. 16, the maximum dispersion of the virtual optical path is 1 field position of the system, and the maximum chromatic aberration value is less than 210 μm; as shown in fig. 20, the maximum dispersion of the real optical path is 1 field position of the system, and the maximum chromatic aberration value is less than 90 μm.

Example 3

Embodiment 3 shows an optical module, as shown in fig. 21, which is different from embodiment 1 in that:

focal length f of the first lens 11 ₁ Is-16300 mm, the focal length f of the second lens 21 ₂ Is 155mm. Table 3 shows the optics of the optical moduleA parameter;

TABLE 3

The optical performance of the optical module of embodiment 3 of the present application is as follows:

fig. 22 to 25 are aberration characterization diagrams of a virtual optical path in embodiment 3, and fig. 26 to 29 are aberration characterization diagrams of a real optical path in embodiment 3.

Fig. 22 and 26 are MTF graphs of the optical module of example 3. In example 3: as shown in fig. 22, the virtual optical path MTF is >0.3 at 15 lp/mm; as shown in fig. 26, the real path MTF is >0.35 at 15 lp/mm.

Fig. 23 and 27 are each a dot arrangement diagram of an optical module of example 3. In embodiment 3, as shown in fig. 23, the maximum value of the image point in the point alignment chart of the virtual optical path is less than 53 μm; as shown in fig. 27, the maximum value of the image point in the point alignment image in the real light path is less than 18 μm.

Fig. 24 and 28 are both field curvature and distortion diagrams of the optical module of example 3. In example 3: as shown in fig. 24, the maximum value of the virtual optical path curvature of field is less than 1.8mm, and as shown in fig. 28, the maximum value of the real optical path curvature of field is less than 0.7mm. Distortion reflects the deformation of the image, in example 3, please continue as shown in fig. 24, the maximum value of the distortion of the virtual optical path occurs in the 1 view field, and the maximum value is less than 35% (absolute value), please continue as shown in fig. 28, the maximum value of the distortion of the real optical path occurs in the 0.4 view field, and the maximum value is less than 0.8% (absolute value).

Fig. 25 and 29 are vertical axis chromatic aberration diagrams, also called as chromatic aberration of magnification, of the optical module of embodiment 3. In example 3: as shown in fig. 25, the maximum dispersion of the virtual optical path is 1 field position of the system, and the maximum chromatic difference value is less than 210 μm; as shown in fig. 29, the maximum dispersion of the real optical path is 1 field position of the system, and the maximum chromatic aberration value is less than 90 μm.

According to another aspect of the embodiments of the present application, there is also provided a head-mounted display device, which includes a housing and the optical module as described above.

The head-mounted display device is, for example, an AR head-mounted device including AR glasses or an AR helmet, and the like, which is not specifically limited in this embodiment of the application.

The specific implementation of the head-mounted display device in the embodiment of the present application may refer to the embodiments of the display module described above, which are not described herein again.

In the above embodiments, the differences between the embodiments are described in emphasis, and different optimization features between the embodiments can be combined to form a better embodiment as long as the differences are not contradictory, and further description is omitted here in consideration of brevity of the text.

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 for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims

1. An optical module, characterized in that it comprises a first lens module (10), a second lens module (20) and a transparent screen (30), wherein the transparent screen (30) is located between the first lens module (10) and the second lens module (20);

the first lens module (10) is configured to be able to transmit a first light ray (02), the first light ray (02) being a real world light ray;

the transparent screen (30) is configured for transmitting the first light rays (02) and is itself capable of emitting second light rays (03);

the first lens module (10) comprises at least one lens comprising a first lens (11), the first lens (11) having a focal length f ₁ ，f ₁ Satisfies the following conditions: f. of ₁ < -1000mm, or f ₁ ＞1000mm。

2. The optical module of claim 1 wherein the focal length f of the optical module is greater than 100mm.

3. The optical module of claim 1 wherein the virtual field of view angle and the real field of view angle of the optical module are each greater than 90 degrees.

4. An optical module according to claim 1, characterised in that the absolute value of the radius of curvature of the first lens (11) is greater than 200mm.

5. An optical module according to claim 1, characterised in that the focal power of the first lens (11) is between-0.01 and 0.01.

6. An optical module according to claim 1, characterized in that the first lens (11) has a central thickness T1, T1 being such that: 0.5mm T1 was constructed of 8mm.

7. Optical module according to claim 1, characterized in that the second lens module (20) comprises a lens group comprising at least a second lens (21).

8. An optical module according to claim 7, characterised in that the focal power of the second lens (21) is between 0 and 0.01.

9. The optical module according to claim 7, wherein the second lens module (20) further comprises a beam splitting element (40), a phase retarder (50) and a polarization reflecting element (60), the beam splitting element (40) is located on a side of the second lens (21) close to the transparent screen (30), the phase retarder (50) and the polarization reflecting element (60) are located on a side of the second lens (21) far away from the transparent screen (30), and the phase retarder (50) is located between the beam splitting element (40) and the polarization reflecting element (60).

10. Optical module according to claim 8, characterized in that the second lens module (20) further comprises a light deflecting element (70), the light deflecting element (70) being located on the side of the polarization reflecting element (60) facing away from the phase retarder (50).

11. The optical module according to claim 10, wherein the beam splitting element (40) is disposed on a surface of the second lens (21) close to the transparent screen (30), the retarder (50), the polarization reflecting element (60) and the polarization element (70) are sequentially stacked to form a stacked element, and the stacked element is disposed on a surface of the second lens (21) far from the transparent screen (30).

12. An optical module according to claim 7, characterized in that the second lens (21) has a central thickness T2, T2 being such that: t2 is more than or equal to 3mm and less than or equal to 10mm.

13. A head-mounted display device, comprising:

a housing; and

the optical module of any one of claims 1-12.