Optical Module, Manufacturing Method Thereof, and Near-Eye Display Device

Abstract

An optical module, a manufacturing method thereof, and a near-eye display device. The optical module has an incident light side and an exit light side, and includes a first lens, a partial reflector, a phase retarder, a second lens, a reflective polarizer, and a light-transmitting structure. The partial reflector is disposed on the first lens near the incident light side, the phase retarder is disposed on the first lens away from the partial reflector side, the second lens is disposed on the phase retarder away from the first lens side, the reflective polarizer is disposed on the second lens near the phase retarder side, and the light-transmitting structure is disposed on the reflective polarizer near the phase retarder side. The reflective polarizer has a reflection axis direction and a transmission axis direction perpendicular to each other, the light-transmitting structure has a minimum refractive direction, the refractive index of the light-transmitting structure for linearly polarized light parallel to the minimum refractive direction is the lowest in the minimum refractive direction, and the angle between the minimum refractive direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees, so that the reflective polarizer has a larger reflection polarization ratio.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to an optical module, a manufacturing method thereof, and a near-eye display device. Background Art

[0002] In virtual reality (VR) devices, a near-eye display device magnifies the image of a display screen through a lens, enabling a person to have an immersive experience. Currently, the main lens technologies are Fresnel lenses and Pancake (ultra-short focal length folded optical path) lenses. Among them, the Pancake (ultra-short focal length folded optical path) lens greatly reduces the distance required between the near-eye display device and the human eye by folding the optical path, making the VR device thinner and lighter. Summary of the Invention

[0003] The key component of the Pancake lens that can achieve reflection and transmission of the optical path is the reflective polarizer. The optical module provided by the embodiments of the present disclosure can reduce the reflectivity of polarized light perpendicular to the reflection axis direction while minimizing the influence on the reflectivity of polarized light parallel to the reflection axis direction, so that the reflective polarizer can have a larger reflection polarization ratio.

[0004] Embodiments of the present disclosure provide an optical module, a manufacturing method thereof, and a near-eye display device.

[0005] At least one embodiment of the present disclosure provides an optical module having an incident light side and an emergent light side, including: a first lens; a partial reflector disposed on a side of the first lens close to the incident light side; a phase retarder disposed on a side of the first lens away from the partial reflector and configured to change light in a circular polarization state into light in a linear polarization state or change light in a linear polarization state into light in a circular polarization state; a second lens disposed on a side of the phase retarder away from the first lens; a reflective polarizer disposed on a side of the second lens close to the phase retarder; and a light-transmitting structure disposed on a side of the reflective polarizer close to the phase retarder and disposed at a gap with the phase retarder. The partial reflector is configured to transmit light incident from the incident light side and configured to reflect light incident from the phase retarder and change the polarization state of the light. The reflective polarizer has mutually perpendicular reflection axis direction and transmission axis direction. The reflective polarizer reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light-transmitting structure has a lowest refraction direction, and the light-transmitting structure has the lowest refractive index for linearly polarized light parallel to the lowest refraction direction in the lowest refraction direction, and the angle between the lowest refraction direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees.

[0006] At least one embodiment of the present disclosure provides a manufacturing method of an optical module. The optical module has a light incident side and a light exiting side. The manufacturing method includes: providing a first lens; providing a partial reflector on a side of the first lens close to the light incident side; providing a phase retarder on a side of the first lens away from the partial reflector, where the phase retarder is configured to change light in a circular polarization state into light in a linear polarization state or change light in a linear polarization state into light in a circular polarization state; providing a second lens on a side of the phase retarder away from the first lens; providing a reflective polarizer on a side of the second lens close to the phase retarder; providing a light-transmitting structure on a side of the reflective polarizer close to the phase retarder, where the light-transmitting structure is provided with a gap from the phase retarder. The partial reflector is configured to transmit light incident from the light incident side, and is configured to reflect light incident from the phase retarder and change the polarization state of the light. The reflective polarizer has mutually perpendicular reflection axis direction and transmission axis direction. The reflective polarizer reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light-transmitting structure has a lowest refraction direction. The light-transmitting structure has the lowest refractive index for linearly polarized light parallel to the lowest refraction direction in the lowest refraction direction. The included angle between the lowest refraction direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees. Description of the Drawings

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure and do not limit the present disclosure.

[0008] Figure 1 It is a schematic structural diagram of a Pancake (ultra-short focal length folded optical path) lens;

[0009] Figure 2 It is the measured reflectivity of a reflective polarizing film;

[0010] Figure 3 It is the measured reflectivity of another reflective polarizing film;

[0011] Figure 4 It is a schematic structural diagram of an optical module provided by an embodiment of the present disclosure;

[0012] Figure 5 It is Figure 4 a schematic diagram of the optical path of the optical module shown;

[0013] Figure 6 Partial top-down view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0014] Figure 7 For Figure 6 Partial cross-sectional view schematic diagram of the stacked structure shown;

[0015] Figure 8 Another partial top-down view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0016] Figure 9 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0017] Figure 10 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0018] Figure 11 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0019] Figure 12 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0020] Figure 13 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0021] Figure 14 Another partial cross-sectional view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0022] Figure 15 Another partial structure schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0023] Figure 16 Data comparison chart of the reflective polarization selection ratio of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure;

[0024] Figure 17 Structure schematic diagram of a near-eye display device provided by an embodiment of the present disclosure;

[0025] Figure 18 Flowchart of a manufacturing method of an optical module provided by an embodiment of the present disclosure;

[0026] Figure 19A flowchart of a manufacturing method for forming a light-transmitting structure on one side of a reflective polarizer provided by an embodiment of the present disclosure; and

[0027] Figure 20 A schematic diagram of another manufacturing method for forming a light-transmitting structure on one side of a reflective polarizer provided by an embodiment of the present disclosure. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "include" or "comprise" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connect" or "couple" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0030] Unless otherwise defined, features such as "parallel", "perpendicular", and "identical" used in the embodiments of the present disclosure include the strict meanings of "parallel", "perpendicular", "identical", etc., as well as cases with certain errors such as "substantially parallel", "substantially perpendicular", and "substantially identical". For example, the above-mentioned "substantially" may mean that the difference between the compared objects is within 10% or 5% of the average value of the compared objects. When the number of a component or element is not specifically indicated in the following text of the embodiments of the present disclosure, it means that the component or element may be one or more, or may be understood as at least one. "At least one" means one or more, and "a plurality" means at least two. The "same-layer setting" in the embodiments of the present disclosure refers to the relationship between multiple film layers formed of the same material after the same step (for example, one-step patterning process). Here, "same layer" does not always mean that the thicknesses of the multiple film layers are the same or the heights of the multiple film layers in the cross-sectional view are the same.

[0031] Figure 1 A schematic diagram of the structure of a Pancake (ultra-short focal length folded optical path) lens. As Figure 1As shown in the figure, the surface of the screen 01 is matched with a wave plate, so that the screen emits right-handed circularly polarized light 1. After passing through the semi-transparent and semi-reflective coating 02, the polarization state of the light remains unchanged and is still right-handed circularly polarized light 2. After passing through the phase retardation film 03, the right-handed circularly polarized light becomes linearly polarized light 3. The polarization direction of the linearly polarized light 3 is parallel to the reflection axis direction of the reflective polarizing film 04. Therefore, the linearly polarized light 3 is reflected by the reflective polarizing film 04 into linearly polarized light 4, and then passes through the phase retardation film 03 again and becomes right-handed circularly polarized light 5. After the right-handed circularly polarized light 5 is reflected by the semi-transparent and semi-reflective coating 02, due to the half-wave loss, the reflected light becomes left-handed circularly polarized light 6. The left-handed circularly polarized light 6 passes through the phase retardation film 03 and becomes linearly polarized light 7 whose polarization direction is parallel to the transmission axis direction of the reflective polarizing film 04, and then passes through the reflective polarizing film 04 to become light 8 and enters the human eye. The Pancake lens completes the folding of the optical path according to the above path, reducing the space required for the lens group.

[0032] The reflective polarizing film 04 has a reflection axis and a projection axis that are perpendicular to each other. The reflectivity of the polarized light component whose polarization direction is parallel to the reflection axis direction on the reflective polarizing film 04 is extremely high, while the transmittance is extremely low; the reflectivity of the polarized light component whose polarization direction is perpendicular to the reflection axis direction (i.e., parallel to the transmission axis direction) on the reflection of this polarizing film is extremely low, while the transmittance is extremely high.

[0033] Therefore, the key component for the Pancake lens to achieve the above-mentioned reflection and transmission of the optical path is the reflective polarizing film 04. An ideal reflective polarizing film completely reflects the polarized light parallel to its reflection axis direction, and the reflectivity of the polarized light perpendicular to its reflection axis direction is zero. However, for an actual reflective polarizing film, it will still reflect some polarized light perpendicular to the reflection axis direction. Since in the Pancake lens, the polarized light parallel to the reflection axis direction reflected by the reflective polarizing film is used for imaging, and the polarized light perpendicular to the reflection axis direction is not needed. These lights that do not participate in imaging are mixed into the folded optical path, which will bring phenomena such as stray light and ghost images that affect the visual experience. Therefore, reducing the reflectivity of the polarized light perpendicular to the reflection axis direction on the surface of the reflective polarizing film as much as possible to make the reflective polarizing film closer to the ideal is an important factor in improving the visual experience of the Pancake lens.

[0034] One of the most important characteristics of a reflective polarizing film is its reflection polarization selectivity ratio, that is, the ratio of the reflectivity (R / / ) of the polarized light with the polarization direction parallel to the reflection axis direction of the reflective polarizing film to the reflectivity (R⊥) of the polarized light with the polarization direction perpendicular to the reflection axis direction of the reflective polarizing film. The reflection polarization selectivity ratio = R / / / R⊥. It can be seen that for the most ideal reflective polarizing film, its reflection polarization selectivity ratio is infinite. In a Pancake lens, the polarized light reflected by the reflective polarizing film parallel to the reflection axis direction is the "signal" for imaging, while the polarized light reflected by it perpendicular to the reflection axis direction is the unnecessary "noise". Therefore, this reflection polarization selectivity ratio can be understood as the "signal-to-noise ratio" of the reflective polarizing film.

[0035] The reflection polarization characteristics of the reflective polarizing film need to be realized by a special material structure. Currently, there are two technical routes: 1. By stacking many layers of birefringent films with different orientation stretchings, making polarized light with different directions interfere between the films to achieve reflection polarization; 2. By nanoimprinting a metal grating on a plastic film material to achieve reflection polarization. Neither of these two technical routes can achieve an extremely high reflection polarization selectivity ratio. For example, for a typical reflective polarizing film, the reflectivity (R / / ) of the polarized light with the polarization direction parallel to the reflection axis direction may be 80%, 90% or 98%, while the reflectivity (R⊥) of the polarized light with the polarization direction perpendicular to the reflection axis direction may be 20%, 10% or 8%.

[0036] Figure 2 is the measured reflectivity of a reflective polarizing film; Figure 3 is the measured reflectivity of another reflective polarizing film. Figure 2 is the reflectivity of the reflective polarizing film realized by adopting the above technical route 1, Figure 3 is the reflectivity of the reflective polarizing film realized by adopting the above technical route 2. As Figure 2 and Figure 3 show, for the polarized light perpendicular to the reflection axis direction, the reflectivity of both reflective polarizing films is still more than 10%. If calculated according to the average value, Figure 2 the reflection polarization selectivity ratio of the reflective polarizing film shown is 9.30, Figure 3 the reflection polarization selectivity ratio of the reflective polarizing film shown is 6.66.

[0037] One of the current solutions to this problem is to form an antireflection layer on the surface of the reflective polarizing film, such as depositing an antireflection film system. However, the antireflection film system has no polarization selectivity ratio. Although it can reduce the reflectivity of the polarized light perpendicular to the reflection axis direction, it also reduces the reflectivity of the polarized light parallel to the reflection axis direction. Although overall, the antireflection film system can indeed improve the reflection polarization selectivity ratio, the reduction of the reflectivity in the reflection axis direction may affect the optical efficiency of the lens and also limit the further improvement of the reflection polarization selectivity ratio.

[0038] In this regard, embodiments of the present disclosure provide an optical module and a manufacturing method thereof. The optical module has a light incident side and a light exit side, and the optical module includes a first lens, a partial reflector, a phase retarder, a second lens, a reflective polarizer, and a light transmissive structure. The partial reflector is disposed on a side of the first lens close to the light incident side, and the phase retarder is disposed on a side of the first lens away from the partial reflector and configured to convert light in a circular polarization state into light in a linear polarization state, or convert light in a linear polarization state into light in a circular polarization state. The second lens is disposed on a side of the phase retarder away from the first lens, the reflective polarizer is disposed on a side of the second lens close to the phase retarder, and the light transmissive structure is disposed on a side of the reflective polarizer close to the phase retarder and is disposed with a gap from the phase retarder. The partial reflector is configured to transmit light incident from the light incident side and configured to reflect light incident from the phase retarder and change the polarization state of the light. The reflective polarizer has a reflection axis direction and a transmission axis direction that are perpendicular to each other. The reflective polarizer reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light transmissive structure has a minimum refractive direction. The refractive index of the light transmissive structure for linearly polarized light parallel to the minimum refractive direction is the lowest in the minimum refractive direction, and the angle between the minimum refractive direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees.

[0039] In the optical module provided by the embodiments of the present disclosure, assuming that the light incident from the light incident side is right-handed circularly polarized light, after passing through the partial reflector, the polarization state of the light remains unchanged. After passing through the phase retarder, it becomes linearly polarized light in a first state. When the polarization direction of the linearly polarized light in the first state is parallel to the reflection axis direction of the reflective polarizer, the light is reflected by the reflective polarizer as linearly polarized light in the first state and becomes right-handed circularly polarized light again after passing through the phase retarder. After the right-handed circularly polarized light is reflected by the partial reflector, due to the half-wave loss, it becomes left-handed circularly polarized light. The left-handed circularly polarized light becomes linearly polarized light in a second state after passing through the phase retarder. The polarization direction of the linearly polarized light in the second state is parallel to the transmission axis direction of the reflective polarizer, and thus passes through the reflective polarizer to become light rays and enter the light exit side of the optical module.

[0040] In the optical module provided by the embodiments of the present disclosure, a light-transmitting structure is provided on one side of the reflective polarizer close to the phase retarder. The light-transmitting structure has a minimum refractive direction. The refractive index of the light-transmitting structure for polarized light parallel to the minimum refractive direction is the lowest in the minimum refractive direction, and the angle between the minimum refractive direction of the light-transmitting structure and the reflection axis direction of the reflective polarizer is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, for polarized light with a polarization direction perpendicular to the reflection axis direction, due to the light-transmitting structure having a minimum refractive direction, the reflection of polarized light with a polarization direction perpendicular to the reflection axis direction can be reduced, the reflection polarization ratio of the reflective polarizing film can be improved, the polarized light with a polarization direction perpendicular to the reflection axis direction entering the folded optical path can be reduced, and the occurrence of phenomena such as stray light and ghost images that affect the visual experience can be avoided, thereby improving the clarity, contrast, and visual experience of the near-eye display device where the optical module is located.

[0041] Compared with the isotropic antireflection film in the prior art, since the isotropic antireflection film has no polarization selectivity ratio, the reflectivity of polarized light perpendicular to the reflection axis direction is reduced while the reflectivity of polarized light parallel to the reflection axis direction is also reduced. The light-transmitting structure provided by the embodiments of the present disclosure has a minimum refractive direction. The light-transmitting structure is anisotropic, and the light-transmitting structure has different refractive indices in the direction perpendicular to the reflection axis direction and in the direction parallel to the reflection axis direction, and the angle between the minimum refractive direction of the light-transmitting structure and the reflection axis direction of the reflective polarizer is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, while the reflectivity of polarized light perpendicular to the reflection axis direction can be reduced, the influence of the light-transmitting structure on the reflectivity of polarized light parallel to the reflection axis direction can be minimized as much as possible, so that the reflective polarizer can have a larger reflection polarization ratio and the adverse influence of the light-transmitting structure on the optical efficiency of the optical module can be avoided.

[0042] Next, the optical module and the manufacturing method of the optical module provided by the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0043] An embodiment of the present disclosure provides an optical module. Figure 4 It is a schematic diagram of an optical module provided by an embodiment of the present disclosure. Figure 5 is Figure 4 A schematic diagram of the optical path of the optical module shown. As Figure 4As shown, the optical module has a light incident side S1 and a light exit side S2. The optical module includes a first lens 100, a partial reflector 110, a phase retarder 120, a second lens 130, a reflective polarizer 140, and a light transmissive structure 150. The partial reflector 110 is disposed on a side of the first lens 100 close to the light incident side S1. The phase retarder 120 is disposed on a side of the first lens 100 away from the partial reflector 110, and is configured to change light in a circular polarization state into light in a linear polarization state, or change light in a linear polarization state into light in a circular polarization state. The second lens 130 is disposed on a side of the phase retarder 120 away from the first lens 100. The reflective polarizer 140 is disposed on a side of the second lens 130 close to the phase retarder 120. The light transmissive structure 150 is disposed on a side of the reflective polarizer 140 close to the phase retarder 120, and is disposed with a gap from the phase retarder 120. The partial reflector 110 is configured to transmit light incident from the light incident side S1, and is configured to reflect light incident from the phase retarder 120 and change the polarization state of the light. The reflective polarizer 140 has a reflection axis direction and a transmission axis direction that are perpendicular to each other. The reflective polarizer 140 reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer 140 transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light transmissive structure 150 has a lowest refraction direction. The light transmissive structure 150 has the lowest refractive index for linearly polarized light parallel to the lowest refraction direction in the lowest refraction direction. The included angle between the lowest refraction direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees.

[0044] As Figure 4 and Figure 5 shown, in order to more clearly illustrate the change in the polarization state of light, it is assumed that the light incident from the light incident side is light 10 in a right-handed circular polarization state (illustrated in a right-handed circular polarization state for illustration purposes only, but not a limitation on the embodiments of the present disclosure). After passing through the partial reflector 110, the polarization state of the light 20 remains unchanged. After passing through the phase retarder 120, the right-handed circular polarization state of the light 20 becomes the first linearly polarized light 30. When the polarization direction of the first linearly polarized light 30 is parallel to the reflection axis direction of the reflective polarizer 140, the light 30 is reflected by the reflective polarizer 140 into the first linearly polarized light 40, and after passing through the phase retarder 120 again, it becomes the right-handed circular polarization state of the light 50. After the right-handed circular polarization state of the light 50 is reflected by the partial reflector 110, due to the half-wave loss, it becomes the left-handed circular polarization state of the light 60. After the left-handed circular polarization state of the light 60 passes through the phase retarder 120, it becomes the second linearly polarized light 70. The polarization direction of the second linearly polarized light 70 is parallel to the transmission axis direction of the reflective polarizer 140, and thus passes through the reflective polarizer 140 to become the light ray 80 and enters the light exit side of the optical module.

[0045] In the optical module provided by the embodiments of the present disclosure, a light-transmitting structure 150 is disposed on a side of the reflective polarizer 140 close to the phase retarder 120. The light-transmitting structure 150 has a minimum refractive direction. The light-transmitting structure 150 has the lowest refractive index for polarized light parallel to the minimum refractive direction in the minimum refractive direction, and the included angle between the minimum refractive direction of the light-transmitting structure 150 and the reflection axis direction of the reflective polarizer 140 is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, for polarized light with a polarization direction perpendicular to the reflection axis direction, due to the light-transmitting structure 150 having a minimum refractive direction, the reflection of polarized light with a polarization direction perpendicular to the reflection axis direction can be reduced, the reflection polarization ratio of the reflective polarizing film can be improved, the polarized light with a polarization direction perpendicular to the reflection axis direction entering the folded optical path can be reduced, the occurrence of phenomena such as stray light and ghosting that affect the visual experience can be avoided, and the clarity, contrast, and visual experience of the near-eye display device where the optical module is located can be improved.

[0046] Compared with the isotropic antireflection film in the prior art, since the isotropic antireflection film has no polarization selectivity ratio, the reflectivity of polarized light parallel to the reflection axis direction is also reduced while reducing the reflectivity of polarized light perpendicular to the reflection axis direction. The light-transmitting structure 150 provided by the embodiments of the present disclosure has a minimum refractive direction. The light-transmitting structure 150 is anisotropic. The light-transmitting structure 150 has different refractive indices in the direction perpendicular to the reflection axis direction and in the direction parallel to the reflection axis direction, and the included angle between the minimum refractive direction of the light-transmitting structure 150 and the reflection axis direction of the reflective polarizer 140 is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, while the reflectivity of polarized light perpendicular to the reflection axis direction can be reduced, the influence of the light-transmitting structure 150 on the reflectivity of polarized light parallel to the reflection axis direction can be minimized as much as possible, so that the reflective polarizer 140 can have a larger reflection polarization ratio and the adverse influence of the light-transmitting structure 150 on the optical efficiency of the optical module can be avoided.

[0047] It should be noted that the reflective polarizer 140 and the phase retarder 120 are aligned, and the reflection axis direction of the reflective polarizer 140 is in the middle of the fast axis and the slow axis of the phase retarder 120, so that the linearly polarized light formed by passing through the phase retarder 120 is parallel to the reflection axis direction of the reflective polarizer 140.

[0048] In some examples, as Figure 4 shown, the first lens 100, the partial reflector 110, and the phase retarder 120 may form a first lens assembly. For example, the second lens 130, the reflective polarizer 140, and the light-transmitting structure 150 may form a second lens assembly. The first lens assembly and the second lens assembly are disposed with a gap.

[0049] In some examples, the partial reflector 110 may be a semi-transmissive and semi-reflective film. For example, the phase retarder 120 may be a quarter-wave plate.

[0050] In some examples, any one of the partial reflector 110, the phase retarder 120, and the reflective polarizer 140 may have a flat or curved shape. For example, any one of the partial reflector 110, the phase retarder 120, and the reflective polarizer 140 may be formed on a flat or curved lens. For example, the materials of the first lens 100 and the second lens 130 may be glass, plastic, etc., and the embodiments of the present disclosure do not limit this.

[0051] For example, as Figure 4 and Figure 5 shown, after the light 60 in the left-handed circular polarization state passes through the phase retarder 120 and becomes the light 70 in the second linear polarization state, since the reflective polarizer 140 will reflect part of the polarized light perpendicular to the reflection axis direction, part of the light 70 in the second linear polarization state will be reflected by the reflective polarizer 140. However, the light 70 in the second linear polarization state is not used for imaging. Thus, adding a light-transmitting structure 150 on the reflective polarizer 140 can reduce the reflection of the light 70 in the second linear polarization state.

[0052] For example, as Figure 4 and Figure 5 shown, after the light 20 in the right-handed circular polarization state passes through the phase retarder 120 and becomes the light 30 in the first linear polarization state, when there is an angle between the polarization direction of the light 30 in the first linear polarization state and the reflection axis direction of the reflective polarizer 140, for example, when there is a deviation in the alignment of the reflective polarizer 140 and the phase retarder 120, the polarized light component of the light 30 in the first linear polarization state perpendicular to the reflection axis direction will also be partially reflected by the reflective polarizer 140. Thus, adding a light-transmitting structure 150 on the reflective polarizer 140 can also reduce the reflection of the polarized light component perpendicular to the reflection axis direction.

[0053] In some examples, the angle between the lowest refractive direction of the light-transmitting structure 150 and the reflection axis direction may be 90 degrees, so that the reflectivity of the polarized light with the polarization direction perpendicular to the reflection axis direction can be minimized. Of course, the embodiments of the present disclosure do not limit this. For example, this angle may also be any value between 70 degrees and 90 degrees.

[0054] In some examples, the reflectivity of the reflective polarizer for the polarized light with the polarization direction perpendicular to the reflection axis direction is R⊥. For the convenience of description, it may be assumed that the reflection axis direction of the reflective polarizer is an isotropic optical medium with a refractive index of n. According to the optical principle, the refractive index of the light-transmitting structure perpendicular to the reflection axis direction is n_low, and the thickness is t. At a certain wavelength λ, if the following conditions can be satisfied: 1) If \(t = \lambda / (4*n_{low})\), the reflectivity at this wavelength is 0. Therefore, the light-transmitting structure can be designed and verified to determine \(n_{low}\) and \(t\) such that \(R_{\perp}\) is as small as possible, thereby minimizing the reflection of polarized light with a polarization direction perpendicular to the reflection axis direction.

[0055] In some examples, the light-transmitting structure 150 has a highest refraction direction. The light-transmitting structure 150 has the highest refractive index for linearly polarized light parallel to the highest refraction direction in the highest refraction direction, and the angle between the highest refraction direction and the reflection axis direction is less than or equal to 20 degrees. Since the refractive index of the light-transmitting structure 150 is generally lower than that of the reflective polarizer 140, adding a structure with a low refractive index on the reflective polarizer 140 will reduce the reflectivity in the reflection axis direction of the reflective polarizer 140. By setting the angle between the highest refraction direction of the light-transmitting structure 150 and the reflection axis direction to be less than or equal to 20 degrees, the reduction in the reflection of polarized light parallel to the reflection axis direction can be minimized. For example, the angle between the highest refraction direction and the reflection axis direction can be 0 degrees, so that the reduction in the reflection of polarized light parallel to the reflection axis direction by the light-transmitting structure 150 can be minimized. Of course, the embodiments of the present disclosure are not limited thereto. For example, the angle can also be any value between 0 degrees and 20 degrees.

[0056] In this example, while the light-transmitting structure 150 can reduce the reflectivity of polarized light perpendicular to the reflection axis direction, by setting the angle between the highest reflection direction of the light-transmitting structure 150 and the reflection axis direction of the reflective polarizer 140 to be less than or equal to 20 degrees, the influence on the reflectivity of polarized light parallel to the reflection axis direction is minimized, and the influence of the light-transmitting structure 150 on the reflectivity of polarized light parallel to the reflection axis direction is minimized as much as possible. Thereby, the reflective polarizer 140 can have a larger reflection polarization ratio, and the adverse effect of the light-transmitting structure 150 on the optical efficiency of the optical module can be avoided.

[0057] Figure 6 It is a partial top view schematic diagram of a stacked structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. Figure 7 is Figure 6 A partial cross-sectional schematic diagram of the stacked structure shown. As Figure 6 and Figure 7 shown, the light-transmitting structure 150 includes a first structure layer 151. The first structure layer 151 includes a plurality of first protrusions 152. In the thickness direction of the first structure layer 151, that is, in the Z direction as shown in the figure, the first protrusions 152 protrude towards the direction close to the first lens assembly or the phase retarder 120. Figure 6 and Figure 7It is schematically shown that the lowest refraction direction of the light-transmitting structure 150 is the X direction, and the highest refraction direction of the light-transmitting structure 150 is the Y direction, but the embodiments of the present disclosure do not limit this. The density of the first protrusions 152 of the first structural layer 151 along the lowest refraction direction is less than the density of the first protrusions 152 in other directions within the reference plane, and the density of the first protrusions 152 along the highest refraction direction is greater than the density of the first protrusions 152 in other directions within the reference plane. The reference plane is the plane where the lowest refraction direction and the highest refraction direction are located. Thus, the density of the first protrusions 152 in the lowest refraction direction is the smallest, and the polarized light parallel to the lowest refraction direction can pass through faster, resulting in the lowest refractive index; the density of the first protrusions 152 in the highest refraction direction is the largest, and the polarized light parallel to the highest refraction direction is more difficult to pass through, resulting in the highest refractive index.

[0058] It should be noted that the density mentioned in the embodiments of the present disclosure refers to the degree of density. For example, the smallest density of the first protrusions 152 along the lowest refraction direction means that the first protrusions 152 are the sparest along the lowest refraction direction, and the number of the first protrusions 152 per unit length along the lowest refraction direction is the least. For example, the largest density of the first protrusions 152 along the highest refraction direction means that the first protrusions 152 are the densest along the highest refraction direction, and the number of the first protrusions 152 per unit length along the highest refraction direction is the most.

[0059] In some examples, such as Figure 6 and Figure 7 shown, the reflection axis direction of the reflection polarizer 140 is the Y direction, the transmission axis direction of the reflection polarizer 140 is the X direction, the density of the first protrusions 152 of the light-transmitting structure 150 in the X direction is the smallest, the X direction is the lowest refraction direction of the light-transmitting structure 150, the density of the first protrusions 152 of the light-transmitting structure 150 in the Y direction is the largest, and the Y direction is the highest refraction direction of the light-transmitting structure 150. Thus, the lowest refraction direction of the light-transmitting structure 150 is perpendicular to the reflection axis direction, and the highest refraction direction of the light-transmitting structure 150 is parallel to the reflection axis direction. Of course, the embodiments of the present disclosure do not limit this. According to the different manufacturing processes and materials of the light-transmitting structure 150, the arrangement form and size of the first protrusions 152 can also be different.

[0060] In some examples, such as Figure 6 and Figure 7 shown, the size of the first protrusions 152 along the lowest refraction direction is greater than the size of the first protrusions 152 along the highest refraction direction. Thus, it can better make the density of the first protrusions 152 in the lowest refraction direction the smallest and better make the density of the first protrusions 152 in the highest refraction direction the largest.

[0061] For example, such as Figure 6 and Figure 7As shown, the ratio of the size of the first protrusion 152 along the lowest refraction direction to the size of the first protrusion 152 along the highest refraction direction is greater than or equal to 3. For example, this ratio can also be greater than or equal to 5.

[0062] In some examples, such as Figure 6 As shown, the orthographic projection of the first protrusion 152 on the reference plane includes the maximum size along the major axis direction M. The angle between the major axis direction M of multiple first protrusions 152 and the lowest refraction direction is less than or equal to 25 degrees. Thus, the smaller the angle between the major axis direction M of the first protrusion 152 and the lowest refraction direction, the more the major axis direction M of the first protrusion 152 deviates towards the lowest refraction direction, and the maximum size of the first protrusion 152 will be arranged along the lowest refraction direction as much as possible. Therefore, the density of the first protrusions 152 in the lowest refraction direction can be made smaller, and the refractive index in the lowest refraction direction can be made lower. For example, the angle between the major axis direction M of multiple first protrusions 152 and the lowest refraction direction can be less than or equal to 15 degrees. For example, this angle can be any value within 25 degrees.

[0063] For example, Figure 6 Schematically shows that the angle between the major axis direction M of each first protrusion 152 and the lowest refraction direction is 0 degrees, and the major axis directions M of multiple first protrusions 152 all extend along the same direction, which is the lowest refraction direction. The maximum sizes of the first protrusions 152 are all arranged along the lowest refraction direction. Therefore, the density of the first protrusions 152 in the lowest refraction direction can be made smaller, and the refractive index in the lowest refraction direction can be made lower.

[0064] In some examples, such as Figure 6 and Figure 7 As shown, the orthographic projection of the first protrusion 152 on the reference plane includes the minor axis direction N perpendicular to the major axis direction M. The angle between the minor axis direction N of multiple first protrusions 152 and the highest refraction direction is less than or equal to 25 degrees. Thus, the smaller the angle between the minor axis direction N of the first protrusion 152 and the highest refraction direction, the more the minor axis direction N of the first protrusion 152 deviates towards the highest refraction direction, and the minor axes of the first protrusions 152 will be arranged along the highest refraction direction as much as possible. Therefore, the density of the first protrusions 152 in the highest refraction direction can be made larger, and the refractive index in the highest refraction direction can be made higher. For example, the angle between the minor axis direction N of multiple first protrusions 152 and the highest refraction direction can be less than or equal to 15 degrees. For example, this angle can be any value within 25 degrees.

[0065] For example, Figure 6 Schematically shows that the angle between the minor axis direction N of each first protrusion 152 and the highest refraction direction is 0 degrees, and the minor axis directions N of multiple first protrusions 152 all extend along the same direction, which is the highest refraction direction.

[0066] It should be noted that the introduction of the major axis direction M and the minor axis direction N does not limit the orthographic projection of the first protrusion 152 on the reference plane to an ellipse. The major axis direction M is only used to illustrate the direction where the maximum dimension is located, and the minor axis direction N is perpendicular to the major axis direction M. For example, the minor axis of the first protrusion 152 can be defined as the line segment or chord obtained by intercepting the orthographic projection of the first protrusion 152 on the reference plane along the minor axis direction N through the midpoint of the above-mentioned maximum dimension. For example, the orthographic projection of the first protrusion 152 on the reference plane can be an ellipse but is not limited to an ellipse, and can also be other regular or irregular figures.

[0067] In some examples, such as Figure 6 and Figure 7 as shown, the gap between two adjacent first protrusions 152 along the lowest refraction direction is greater than the gap between two adjacent first protrusions 152 along the highest refraction direction. Thus, the refractive index in the lowest refraction direction can be better minimized, and the refractive index in the highest refraction direction can be better maximized.

[0068] In some examples, such as Figure 6 and Figure 7 as shown, the gap between two adjacent first protrusions 152 along the lowest refraction direction is greater than the gap between two adjacent first protrusions 152 in other directions within the reference plane. Thus, the refractive index in the lowest refraction direction can be better minimized.

[0069] In some examples, the gap between two adjacent first protrusions 152 along the highest refraction direction is less than the gap between two adjacent first protrusions 152 in other directions within the reference plane. Thus, the refractive index in the highest refraction direction can be better maximized.

[0070] In some examples, such as Figure 6 as shown, along the highest refraction direction, multiple first protrusions 152 overlap, and along the lowest refraction direction, multiple first protrusions 152 overlap. Thus, multiple first protrusions 152 can be arranged more densely in the lowest refraction direction and the highest refraction direction, enabling the laminated structure of the reflective polarizer 140 and the light-transmitting structure 150 to have better optical performance, better reducing the reflection perpendicular to the reflection axis direction, and minimizing the reduction of the reflection of polarized light parallel to the reflection axis direction as much as possible.

[0071] Figure 8 This is a partial top view schematic diagram of another laminated structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. Such as Figure 8As shown, the lowest refraction direction of the light-transmitting structure 150 is the X direction. The major axis directions M of the multiple first protrusions 152 of the light-transmitting structure 150 are not arranged in the same direction. The major axis directions M of the multiple first protrusions 152 are different, and the shapes and sizes of the multiple first protrusions 152 are also different. However, the major axis directions M of the multiple first protrusions 152 of the light-transmitting structure 150 satisfy that the angle with the lowest refraction direction (i.e., the X direction) is less than or equal to 25 degrees. Of course, the embodiments of the present disclosure do not limit this. For example, this angle can also be less than or equal to 15 degrees.

[0072] For example, as Figure 8 As shown, the highest refraction direction of the light-transmitting structure 150 is the Y direction. The minor axis directions N of the multiple first protrusions 152 of the light-transmitting structure 150 are not arranged in the same direction. The minor axis directions N of the multiple first protrusions 152 are different. However, the minor axis directions N of the multiple first protrusions 152 of the light-transmitting structure 150 satisfy that the angle with the highest refraction direction is less than or equal to 25 degrees. Of course, the embodiments of the present disclosure do not limit this. For example, this angle can also be less than or equal to 15 degrees. Figure 8 Only the arrangement form of the multiple first protrusions 152 is exemplarily illustrated, and it does not limit the embodiments of the present disclosure.

[0073] Figure 9 This is a partial cross-sectional schematic diagram of another laminated structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 9 As shown, in the thickness direction of the first structural layer 151, that is, in the Z direction as shown in the figure, the sizes of the multiple first protrusions 152 are not equal, and the embodiments of the present disclosure do not limit this.

[0074] Figure 10 This is a partial cross-sectional schematic diagram of another laminated structure of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 10 As shown, the first structural layer 151 further includes a base layer 153, and the multiple first protrusions 152 are located on the side of the base layer 153 away from the reflective polarizer 140. In the figure, it is schematically shown that the sizes of the multiple first protrusions 152 along the Z direction and the Y direction are the same. The embodiments of the present disclosure do not limit this, and they can also be different.

[0075] In some examples, as Figure 10 As shown, the base layer 153 and the multiple first protrusions 152 are of an integral structure. The light-transmitting structure 150 can be formed by using film layers of different thicknesses. When the thickness of the film layer is relatively thin, for example, when the thickness of the film layer is within 300 nm, the first structural layer 151 can only include the multiple first protrusions 152 (for example, as Figure 7As shown). When the thickness of the film layer is relatively thick, for example, when the thickness of the film layer exceeds 300 nm, the first structural layer 151 may include a base layer 153. The base layer 153 and the plurality of first protrusions 152 are made of the same material, and the base layer 153 and the plurality of first protrusions 152 are of an integral structure.

[0076] Figure 11 FIG. is a partial cross-sectional schematic view of a stacked structure of another reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 11 shown, the base layer 153 is an adhesive layer, so that the first structural layer 151 can be better attached to the reflective polarizer 140. The embodiment of the present disclosure does not limit the material of the adhesive layer.

[0077] In some examples, as Figure 11 shown, the base layer 153 may be an optical device, so that an optical function can be realized. For example, the refractive index of the base layer 153 may be greater than the refractive index of the reflective polarizing film. For example, the refractive index of the base layer 153 is also greater than the refractive index of the structure where the plurality of first protrusions 152 are located. Of course, the embodiment of the present disclosure does not limit this, and can be adjusted according to the design of the light-transmitting structure 150 and the optical module. It should be noted that the refractive index here refers to the refractive index in a certain polarization direction.

[0078] Figure 12 FIG. is a partial cross-sectional schematic view of a stacked structure of another reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 12 shown, the light-transmitting structure 150 further includes a second structural layer 154. The second structural layer 154 is stacked with the first structural layer 151 and is located on the side of the first structural layer 151 away from the reflective polarizer 140. The second structural layer 154 includes a plurality of second protrusions 155. In the thickness direction of the second structural layer 154, that is, in the Z direction as shown in the figure, the second protrusions 155 protrude toward the direction close to the first lens assembly or the phase retarder 120. By providing the second structural layer 154, the light-transmitting structure 150 can be optimized and designed in the thickness direction. For example, it can be made that in the thickness direction of the light-transmitting structure 150, the refractive index of the light-transmitting structure 150 changes gradually, so that the light-transmitting structure 150 can have a better anti-reflection effect on as many wavelengths as possible.

[0079] In some examples, as Figure 12 shown, the materials of the second protrusions 155 and the first protrusions 152 are different. For example, the orthographic projections of the plurality of second protrusions 155 in the reference plane fall within the orthographic projections of the plurality of first protrusions 152 in the reference plane.

[0080] Figure 13 FIG. is a partial cross-sectional schematic view of a stacked structure of another reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. AsFigure 13 As shown, the materials of the second protrusions 155 and the first protrusions 152 are different. The orthographic projections of the plurality of second protrusions 155 in the reference plane fall within the orthographic projections of the plurality of first protrusions 152 in the reference plane. The first structural layer 151 further includes a base layer 153, and the material of the base layer 153 is the same as that of the first protrusions 152. Thus, in the thickness direction of the light-transmitting structure 150, the refractive index of the light-transmitting structure 150 gradually changes slowly, so that the light-transmitting structure 150 can have a relatively good anti-reflection effect on all wavelengths.

[0081] Figure 14 FIG. is a partial cross-sectional schematic view of a stacked structure of another reflection polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 14 shown, the materials of the second protrusions 155 and the first protrusions 152 are different, and the orthographic projections of the plurality of second protrusions 155 in the reference plane overlap with the orthographic projections of the plurality of first protrusions 152 in the reference plane.

[0082] In some examples, the light-transmitting structure 150 may further include a multi-layer structure. For example, a third structural layer is further stacked on the side of the second structural layer 154 away from the first structural layer 151. The third structural layer includes a plurality of third protrusions, and in the thickness direction of the third structural layer, the third protrusions protrude toward the direction close to the first lens assembly or the phase retarder 120. Thus, the light-transmitting structure 150 can be optimized and designed in the thickness direction. The structural design of the third protrusions is the same as that of the second protrusions 155 and will not be elaborated here. Of course, the number of layers of the multi-layer structure included in the light-transmitting structure 150 in the embodiments of the present disclosure is not limited.

[0083] In some examples, as Figures 6 to 14 shown, along the thickness of the first structural layer 151, the value range of the size of the first protrusions 152 is 50 nm - 300 nm. For example, the value range of this size may be 70 nm - 150 nm. For example, this size may be any value between 50 nm and 300 nm. For example, as Figures 12 to 14 shown, along the thickness of the second structural layer 154, the value range of the size of the second protrusions 155 is 50 nm - 300 nm. For example, this size may be any value between 50 nm and 300 nm.

[0084] In some examples, as Figures 6 to 14 shown, the value range of the maximum size in the major axis direction M of the first protrusions 152 is between several nanometers and several hundred nanometers. For example, this size may be any value within the above value range.

[0085] In some examples, as Figures 6 to 14As shown, the dimension of the first protrusion 152 in the minor axis direction N ranges from 1 nm to 80 nm. For example, the range of this dimension can be 5 nm to 30 nm. For example, this dimension can be any value between 1 nm and 80 nm.

[0086] In some examples, as Figures 6 to 14 shown, the gap between two adjacent first protrusions 152 ranges from 1 nm to 80 nm. For example, the range of this gap can be 5 nm to 30 nm. For example, this gap can be any value between 1 nm and 80 nm.

[0087] Figure 15 This is a partial structural schematic diagram of a laminated structure of another reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 15 shown, a plurality of first protrusions 152 are connected so that the first structural layer 151 includes a plurality of first grooves 156. In order to clearly show the arrangement and opening shape of the plurality of first grooves 156, Figure 15 only the internal dotted lines of three first grooves 156 are shown for assistance. Figure 15 It is schematically shown that the lowest refraction direction of the light-transmitting structure 150 is the X direction, and the highest refraction direction of the light-transmitting structure 150 is the Y direction, but the embodiments of the present disclosure do not limit this. The density of the first grooves 156 of the first structural layer 151 along the lowest refraction direction is less than the density of the first grooves 156 in other directions in the reference plane, and the density of the first grooves 156 along the highest refraction direction is greater than the density of the first grooves 156 in other directions in the reference plane. The reference plane is the plane where the lowest refraction direction and the highest refraction direction are located. Thus, the density of the first grooves 156 in the lowest refraction direction is the smallest, and the polarized light parallel to the lowest refraction direction can pass through faster, so the refractive index is the lowest; the density of the first grooves 156 in the highest refraction direction is the largest, and the polarized light parallel to the highest refraction direction is more difficult to pass through, so the refractive index is the highest.

[0088] It should be noted that the density mentioned in the embodiments of the present disclosure refers to the degree of density. For example, the smallest density of the first grooves 156 along the lowest refraction direction means that the first grooves 156 are the sparest along the lowest refraction direction, and the number of the first grooves 156 per unit length along the lowest refraction direction is the least. For example, the largest density of the first grooves 156 along the highest refraction direction means that the first grooves 156 are the densest along the highest refraction direction, and the number of the first grooves 156 per unit length along the highest refraction direction is the most.

[0089] In some examples, as Figure 15As shown, the Y direction is the reflection axis direction of the reflective polarizer 140, the X direction is the transmission axis direction of the reflective polarizer 140. The density of the first grooves 156 of the light-transmitting structure 150 in the X direction is the smallest, the X direction is the lowest refraction direction of the light-transmitting structure 150, the density of the first grooves 156 of the light-transmitting structure 150 in the Y direction is the largest, and the Y direction is the highest refraction direction of the light-transmitting structure 150. Thus, the lowest refraction direction of the light-transmitting structure 150 is perpendicular to the reflection axis direction, and the highest refraction direction of the light-transmitting structure 150 is parallel to the reflection axis direction. Of course, the embodiments of the present disclosure are not limited thereto. According to the different manufacturing processes and materials of the light-transmitting structure 150, the arrangement form and size of the first grooves 156 may also be different.

[0090] In some examples, as Figure 15 shown, the size of the first groove 156 along the lowest refraction direction is greater than the size of the first groove 156 along the highest refraction direction. Thus, it is possible to better minimize the density of the first grooves 156 in the lowest refraction direction and better maximize the density of the first grooves 156 in the highest refraction direction.

[0091] In some examples, as Figure 15 shown, the ratio of the size of the first groove 156 along the lowest refraction direction to the size of the first groove 156 along the highest refraction direction is greater than or equal to 3. For example, this ratio may also be greater than or equal to 5.

[0092] In some examples, as Figure 15 shown, the orthographic projection of the first groove 156 on the reference plane includes the maximum size along the major axis direction M. The included angle between the major axis direction M of the plurality of first grooves 156 and the lowest refraction direction is less than or equal to 25 degrees. Thus, the smaller the included angle between the groove direction of the first protrusion 152 and the lowest refraction direction, the more the major axis direction M of the first groove 156 deviates towards the lowest refraction direction, and the maximum size of the first groove 156 will be arranged as much as possible along the lowest refraction direction. Thus, it is possible to better minimize the density of the first grooves 156 in the lowest refraction direction, and the refractive index in the lowest refraction direction can be made lower. For example, the included angle between the major axis direction M of the plurality of first grooves 156 and the lowest refraction direction may be less than or equal to 15 degrees. For example, this angle may be any value within 25 degrees.

[0093] For example, Figure 15 schematically shows that the included angle between the major axis direction M of each first groove 156 and the lowest refraction direction is 0 degrees, and the major axis directions M of the plurality of first grooves 156 all extend along the same direction, which is the lowest refraction direction. The maximum sizes of the first grooves 156 are all arranged along the lowest refraction direction. Thus, it is possible to better minimize the density of the first grooves 156 in the lowest refraction direction, and the refractive index in the lowest refraction direction can be made lower.

[0094] In some examples, such as Figure 15 shown, the positive projection of the first groove 156 on the reference plane includes a minor axis direction N perpendicular to the major axis direction M. The angle between the minor axis direction N of multiple first grooves 156 and the highest refraction direction is less than or equal to 25 degrees. Thus, the smaller the angle between the minor axis direction N of the first groove 156 and the highest refraction direction, the more the minor axis direction N of the first groove 156 deviates towards the highest refraction direction, and the minor axis of the first groove 156 will be arranged along the highest refraction direction as much as possible. Therefore, it can better make the density of the first grooves 156 in the highest refraction direction larger, and the refractive index in the highest refraction direction can be made higher. For example, the angle between the minor axis direction N of multiple first grooves 156 and the highest refraction direction can be less than or equal to 15 degrees. For example, this angle can be any value within 25 degrees.

[0095] For example, Figure 15 schematically shows that the angle between the minor axis direction N of each first groove 156 and the highest refraction direction is 0 degree, and the minor axis directions N of multiple first grooves 156 all extend along the same direction, and this direction is the highest refraction direction.

[0096] It should be noted that the introduction of the major axis direction M and the minor axis direction N does not limit the positive projection of the first groove 156 on the reference plane to an ellipse. The major axis direction M is only used to illustrate the direction where the maximum dimension is located, and the minor axis direction N is perpendicular to the major axis direction M. For example, the minor axis of the first groove 156 can be defined as the line segment or chord obtained by intercepting the positive projection of the first groove 156 on the reference plane along the minor axis direction N through the midpoint of the above-mentioned maximum dimension. For example, the positive projection of the first groove 156 on the reference plane can be an ellipse but is not limited to an ellipse, and can also be other regular or irregular figures.

[0097] In some examples, such as Figure 15 shown, the gap between two adjacent first grooves 156 along the lowest refraction direction is greater than the gap between two adjacent first grooves 156 along the highest refraction direction. Thus, it can better make the density of the first grooves 156 in the lowest refraction direction the smallest, and better make the density of the first grooves 156 in the highest refraction direction the largest.

[0098] In some examples, such as Figure 15 shown, the gap between two adjacent first grooves 156 along the lowest refraction direction is greater than the gap between two adjacent first grooves 156 in other directions in the reference plane. Thus, it can better make the refractive index in the lowest refraction direction the smallest.

[0099] In some examples, the gap between two adjacent first grooves 156 along the highest refraction direction is less than the gap between two adjacent first grooves 156 in other directions in the reference plane. Thus, it can better make the refractive index in the highest refraction direction the largest.

[0100] In some examples, such as Figure 15 As shown, along the highest refraction direction, the plurality of first grooves 156 overlap, and along the lowest refraction direction, the plurality of first grooves 156 overlap. Thus, the plurality of first grooves 156 can be arranged more densely in the lowest refraction direction and the highest refraction direction, so that the stacked structure of the reflective polarizer 140 and the light-transmitting structure 150 has better optical performance, better reduces the reflection perpendicular to the reflection axis direction, and minimizes the reduction of the reflection of the polarized light parallel to the reflection axis direction.

[0101] In some examples, the long axis directions M of the multiple first grooves 156 of the light-transmitting structure 150 may not be arranged in the same direction, the long axis directions M of the multiple first grooves 156 may be different, and the shapes and sizes of the multiple first grooves 156 may be different. However, the long axis directions M of the multiple first grooves 156 of the light-transmitting structure 150 satisfy that the angle with the lowest refraction direction (i.e., the X direction) is less than or equal to 25 degrees. Of course, the embodiments of the present disclosure are not limited to this, for example, the angle may also be less than or equal to 15 degrees.

[0102] In some examples, the short axis directions N of the multiple first grooves 156 of the light-transmitting structure 150 may not be arranged in the same direction, and the short axis directions N of the multiple first grooves 156 may also be different. However, the short axis directions N of the multiple first grooves 156 of the light-transmitting structure 150 satisfy that the angle with the highest refraction direction is less than or equal to 25 degrees. Of course, the embodiments of the present disclosure are not limited to this, for example, the angle may also be less than or equal to 15 degrees.

[0103] In some examples, such as Figure 15 As shown, the depth dimensions of the plurality of first grooves 156 may be unequal, and the embodiments of the present disclosure are not limited thereto.

[0104] In some examples, the plurality of second protrusions 155 of the second structural layer 154 included in the light-transmitting structure 150 may also be connected so that the second structural layer 154 includes a plurality of second grooves, and the orthographic projections of the plurality of first grooves 156 on the reference plane fall within the orthographic projections of the plurality of second grooves on the reference plane, or the orthographic projections of the plurality of first grooves 156 on the reference plane overlap with the orthographic projections of the plurality of second grooves on the reference plane. Thus, the light-transmitting structure 150 may be optimized and designed in the thickness direction of the light-transmitting structure 150. For example, the refractive index of the light-transmitting structure 150 may be gradually changed in the thickness direction of the light-transmitting structure 150, so that the light-transmitting structure 150 may have a better effect of reducing reflection for as many wavelengths as possible.

[0105] In some examples, by adjusting the size or density of the first protrusion 152, the second protrusion 155, the first groove 156, or the second groove, the refractive index of the light-transmitting structure 150 in the direction perpendicular to the reflection axis can be adjusted to make the refractive index as low as possible or the lowest, so that the reflectivity of the reflective polarizer 140 in the direction perpendicular to the reflection axis can be reduced to the greatest extent. For example, the numerical range of the refractive index of the light-transmitting structure 150 in the direction perpendicular to the reflection axis can be 1.15 - 1.35. For example, the numerical range of this refractive index can also be 1.20 - 1.30. For example, this refractive index can be any value between 1.15 - 1.35.

[0106] Figure 16 This is a data comparison chart of the reflection polarization selection ratio of a reflective polarizer and a light-transmitting structure provided by an embodiment of the present disclosure. As Figure 16 shown, calculated according to the average value, the reflectivities (R⊥) of the reflective polarizer 1 and the reflective polarizer 2 in the direction perpendicular to the reflection axis are 10.99% and 9% respectively. The polarized light with the polarization direction perpendicular to the reflection axis will also be reflected, which will cause adverse phenomena such as stray light and ghost images that affect the visual experience.

[0107] After adding an isotropic antireflection film to the reflective polarizer 1, for example, after using 3 different isotropic antireflection films 1, 2, and 3, compared with not adding an antireflection film, the reflectivity (R⊥) in the direction perpendicular to the reflection axis has a certain reduction. The values of R⊥ are 6.41%, 8.27%, and 7.41% respectively; compared with not adding an antireflection film, the reflection polarization selection ratio (R / / / R⊥) has also increased. However, the reflectivity (R / / ) in the direction parallel to the reflection axis has a relatively obvious reduction, which will affect the optical efficiency.

[0108] After adding the light-transmitting structure provided by the embodiment of the present disclosure to the reflective polarizer 1, its reflectivity (R⊥) in the direction perpendicular to the reflection axis is 4%, which is significantly lower than the reflectivity (R⊥) in the direction perpendicular to the reflection axis after adding the isotropic antireflection film. At the same time, its reflectivity (R / / ) in the direction parallel to the reflection axis is 96%, which is significantly higher than the reflectivity (R / / ) in the direction parallel to the reflection axis after adding the isotropic antireflection film, and the reduction of the reflectivity (R / / ) in the direction parallel to the reflection axis of the reflective polarizer without adding an antireflection film is very small. The reflection polarization selection ratio (R / / / R⊥) has also been significantly improved. The value of the reflection polarization selection ratio in this example is 24, which is basically twice the reflection polarization selection ratio after adding the isotropic antireflection film. Thus, it can not only reduce the reflectivity of the polarized light in the direction perpendicular to the reflection axis, but also have no adverse impact on the optical efficiency.

[0109] An embodiment of the present disclosure also provides a near-eye display device. Figure 17The structural schematic diagram of a near-eye display device provided by an embodiment of the present disclosure. As Figure 17 shown, the near-eye display device includes any one of the above optical modules and a display 200. The display 200 is located on the light incident side of the optical module. A polarizer 210 is provided on the side of the display close to the optical module. The polarizer 210 is configured to polarize the light emitted from the display into circularly polarized light. Thus, the near-eye display device has the beneficial effects corresponding to the beneficial effects of the optical module, which will not be elaborated here.

[0110] An embodiment of the present disclosure also provides a manufacturing method of an optical module. Figure 18 The flowchart of a manufacturing method of an optical module provided by an embodiment of the present disclosure. The optical module has a light incident side and a light exit side. As Figure 18 shown, the manufacturing method of the optical module includes:

[0111] S1: Provide a first lens;

[0112] S2: Provide a partial reflector on the side of the first lens close to the light incident side;

[0113] S3: Provide a phase retarder on the side of the first lens away from the partial reflector. The phase retarder is configured to change circularly polarized light into linearly polarized light or change linearly polarized light into circularly polarized light;

[0114] S4: Provide a second lens on the side of the phase retarder away from the first lens;

[0115] S5: Provide a reflective polarizer on the side of the second lens close to the phase retarder; and

[0116] S6: Provide a light-transmitting structure on the side of the reflective polarizer close to the phase retarder. The light-transmitting structure is arranged with a gap from the phase retarder.

[0117] In the manufacturing method, a partial reflector is configured to transmit light incident from the light incident side, and is configured to reflect light incident from the phase retarder and change the polarization state of the light. The reflective polarizer has reflection axis directions and transmission axis directions that are perpendicular to each other. The reflective polarizer reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light-transmitting structure has a lowest refractive direction. The light-transmitting structure has the lowest refractive index for linearly polarized light parallel to the lowest refractive direction in the lowest refractive direction. The included angle between the lowest refractive direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, for polarized light with a polarization direction perpendicular to the reflection axis direction, due to the light-transmitting structure having the lowest refractive direction, the reflection of polarized light with a polarization direction perpendicular to the reflection axis direction can be reduced, the reflection polarization ratio of the reflective polarizing film can be increased, the polarized light with a polarization direction perpendicular to the reflection axis direction entering the folded optical path can be reduced, and the occurrence of phenomena such as stray light and ghost images that affect the visual experience can be avoided, thereby improving the clarity, contrast, and visual experience of the near-eye display device where the optical module is located.

[0118] In some examples, a first lens assembly can be formed by sequentially passing through step S1, step S2, and step S3. For example, a second lens assembly can be formed by sequentially passing through step 4, step 5, and step 6. The formed first lens assembly and second lens assembly are arranged with a gap therebetween.

[0119] For example, providing the light-transmitting structure on the side of the reflective polarizer close to the phase retarder includes forming the light-transmitting structure on the side of the reflective polarizer close to the phase retarder.

[0120] Figure 19 The flowchart of a manufacturing method for forming a light-transmitting structure on one side of a reflective polarizer provided by an embodiment of the present disclosure. As Figure 19 shown, forming the light-transmitting structure on one side of the reflective polarizer includes the following steps:

[0121] S100: Form an imprint pattern opposite to the structural features of the light-transmitting structure on the imprint template so that the light-transmitting structure can be formed through the imprint template;

[0122] S200: Coat a material layer on the side of the imprint template having the imprint pattern;

[0123] S300: Align and bond the uncured material layer with the reflective polarizer so that the included angle between the lowest refractive direction of the formed light-transmitting structure and the reflection axis direction of the reflective polarizer is greater than or equal to 70 degrees and less than or equal to 90 degrees;

[0124] S400: Cure the material layer to form a light-transmitting structure on one side of the reflective polarizer;

[0125] S500: Remove the imprint template.

[0126] In the manufacturing method provided by the present disclosure embodiment, by aligning and laminating the material layer and the reflective polarizer, the angle between the minimum refractive direction of the light-transmitting structure formed on the reflective polarizer and the reflection axis direction of the reflective polarizer is greater than or equal to 70 degrees and less than or equal to 90 degrees. Thus, when the reflective polarizer and the light-transmitting structure are used in the above optical module, while reducing the reflectivity of the polarized light perpendicular to the reflection axis direction, it is also possible to minimize the influence of the light-transmitting structure on the reflectivity of the polarized light parallel to the reflection axis direction. Thereby, the reflective polarizer can have a larger reflection polarization ratio, reducing the polarized light with a polarization direction perpendicular to the reflection axis direction from entering the folded optical path, avoiding the occurrence of phenomena such as stray light and ghosting that affect the visual experience, and improving the clarity, contrast, and visual experience of the near-eye display device where the optical module is located.

[0127] For example, the imprint template can be a polymer soft template. For example, the material of the imprint template can be a material that transmits ultraviolet light. For example, the material of the imprint template can be polydimethylsiloxane (PDMS). For example, the imprint template can be transferred from a hard template etched by electron beam.

[0128] For example, the material layer can be a transparent polymer layer. For example, the material layer is an ultraviolet-curable organic resin formulation, which can be mainly composed of acrylic monomers, acrylic polymers, cross-linking agents, ultraviolet initiators, etc. For example, in addition to the above acrylic-based polymer materials, polymer materials such as liquid crystal polymers, polyesters, polysiloxanes, and inorganic materials such as titanium dioxide, zirconium dioxide, alumina, and silicon nitride can also be used, without limitation.

[0129] For example, the material layer can be formed by slit coating, microgravure coating, or spin coating.

[0130] For example, the imprint template can be adjusted to align and laminate the uncured material layer with the reflective polarizer. For example, the reflective polarizer can also be adjusted to align and laminate the uncured material layer with the reflective polarizer.

[0131] For example, ultraviolet light can be applied to cure the material layer, so that the bonding force between the material layer and the reflective polarizer is stronger than that between the material layer and the imprint template.

[0132] Figure 20 Schematic diagram of another manufacturing method for forming a light-transmitting structure on one side of a reflective polarizer provided by an embodiment of the present disclosure. As Figure 20As shown, an anisotropic imprint pattern 310 is formed on the imprint template 300, and the imprint pattern 310 is opposite to the structural features of the light-transmitting structure 150; a material layer 320 is coated on the side of the imprint template 300 having the imprint pattern 310; the uncured material layer 320 is aligned and bonded with the reflective polarizer 140 so that the included angle between the minimum refraction direction of the formed light-transmitting structure 150 and the reflection axis direction of the reflective polarizer 140 is greater than or equal to 70 degrees and less than or equal to 90 degrees; ultraviolet light UV is applied to cure the material layer 320 to form the light-transmitting structure 150 on the reflective polarizer 140; the imprint template is removed, thereby forming a reflective polarizer 140 with the light-transmitting structure 150.

[0133] In some examples, the imprint template can also be a cylindrical roller structure, and the imprint pattern is formed on the cylindrical roller structure. For example, the imprint pattern can be transferred to the material layer by means of roll printing.

[0134] In some examples, a material layer can also be coated on the reflective polarizer, and then the imprint template is used to imprint on the material layer to form the light-transmitting structure.

[0135] In some examples, a "top-down" method such as photolithography or self-assembled template etching can also be used to first form the material layer and then etch it to form the light-transmitting structure on the reflective polarizer. For example, a "bottom-up" method such as oblique angle coating or liquid crystal coating can also be used to form the light-transmitting structure on the reflective polarizer.

[0136] The following points need to be noted:

[0137] (1) In the drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are involved, and other structures can refer to the general design.

[0138] (2) Without conflict, the features in the same embodiment and different embodiments of the present disclosure can be combined with each other.

[0139] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. An optical module having a light incident side and a light exit side, comprising: A first lens; A partial reflector disposed on a side of the first lens close to the light incident side; A phase retarder disposed on a side of the first lens away from the partial reflector, configured to convert light in a circular polarization state into light in a linear polarization state, or convert light in a linear polarization state into light in a circular polarization state; A second lens disposed on a side of the phase retarder away from the first lens; A reflective polarizer disposed on a side of the second lens close to the phase retarder; And A light transmissive structure disposed on a side of the reflective polarizer close to the phase retarder and spaced apart from the phase retarder, wherein the partial reflector is configured to transmit light incident from the light incident side and configured to reflect light incident from the phase retarder and change the polarization state of the light, the reflective polarizer has mutually perpendicular reflection axis direction and transmission axis direction, the reflective polarizer reflects linearly polarized light parallel to the reflection axis direction in the reflection axis direction and keeps the polarization state of the linearly polarized light unchanged, the reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged, the light transmissive structure has a lowest refraction direction, and the light transmissive structure has the lowest refractive index for linearly polarized light parallel to the lowest refraction direction in the lowest refraction direction, the included angle between the lowest refraction direction and the reflection axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees.

2. The optical module according to claim 1, wherein, The light transmissive structure has a highest refraction direction, and the light transmissive structure has the highest refractive index for linearly polarized light parallel to the highest refraction direction in the highest refraction direction, the included angle between the highest refraction direction and the reflection axis direction is less than or equal to 20 degrees.

3. The optical module according to claim 2, wherein, The light transmissive structure includes a first structure layer, the first structure layer includes a plurality of first protrusions, and in the thickness direction of the first structure layer, the first protrusions protrude towards the phase retarder, the density of the first protrusions of the first structure layer along the lowest refraction direction is less than the density of the first protrusions in other directions on a reference plane, and the density of the first protrusions along the highest refraction direction is greater than the density of the first protrusions in other directions on the reference plane, the reference plane is the plane where the lowest refraction direction and the highest refraction direction are located.

4. The optical module according to claim 3, wherein, The size of the first protrusions along the lowest refraction direction is greater than the size of the first protrusions along the highest refraction direction.

5. The optical module according to claim 4, wherein, The positive projection of the first protrusions on the reference plane includes the maximum size in the long axis direction, and the included angle between the long axis directions of the plurality of first protrusions and the lowest refraction direction is less than or equal to 25 degrees.

6. The optical module according to claim 5, wherein, The positive projection of the first protrusions on the reference plane includes a short axis direction perpendicular to the long axis direction, and the included angle between the short axis directions of the plurality of first protrusions and the highest refraction direction is less than or equal to 25 degrees.

7. The optical module according to claim 3, wherein, The gap between two adjacent first protrusions along the lowest refraction direction is greater than the gap between two adjacent first protrusions along the highest refraction direction.

8. The optical module according to any one of claims 3-7, wherein, The first structural layer further includes a base layer, and the plurality of first protrusions are located on a side of the base layer away from the reflective polarizer.

9. The optical module according to claim 8, wherein, The base layer and the plurality of first protrusions are of an integral structure.

10. The optical module according to any one of claims 3-7, wherein, The light-transmitting structure further includes a second structural layer, which is stacked with the first structural layer and is located on a side of the first structural layer away from the reflective polarizer. The second structural layer includes a plurality of second protrusions, and in the thickness direction of the second structural layer, the second protrusions protrude toward the phase retarder.

11. The optical module according to claim 10, wherein, The materials of the second protrusions and the first protrusions are different, and the orthographic projections of the plurality of second protrusions on the reference plane fall within the orthographic projections of the plurality of first protrusions on the reference plane, or the orthographic projections of the plurality of second protrusions on the reference plane overlap with the orthographic projections of the plurality of first protrusions on the reference plane.

12. The optical module according to claim 10, wherein, The materials of the second protrusions and the first protrusions are different, and the orthographic projections of the plurality of second protrusions on the reference plane fall within the orthographic projections of the plurality of first protrusions on the reference plane. The first structural layer further includes a base layer, and the material of the base layer is the same as that of the first protrusions.

13. The optical module according to any one of claims 3-7, wherein, Along the thickness of the first structural layer, the size of the first protrusions ranges from 50 nm to 300 nm. The gap between two adjacent first protrusions is less than or equal to 80 nm.

14. The optical module according to any one of claims 3-7, wherein, Along the highest refraction direction, the plurality of first protrusions overlap, and along the lowest refraction direction, the plurality of first protrusions overlap.

15. The optical module according to any one of claims 3-7, wherein, The plurality of first protrusions are connected so that the first structural layer includes a plurality of first grooves. The density of the first grooves in the first structural layer along the lowest refraction direction is less than the density of the first grooves in other directions on the reference plane, and the density of the first grooves in the first structural layer along the highest refraction direction is greater than the density of the first grooves in other directions on the reference plane.

16. A near-eye display device, comprising: The optical module according to any one of claims 1-15, and A display, located on the light-incident side of the optical module, Wherein, a polarizer is provided on a side of the display close to the optical module, and the polarizer is configured to polarize the light emitted from the display into circularly polarized light.

17. A manufacturing method of an optical module, the optical module having a light-incident side and a light-emitting side, the manufacturing method comprising: Providing a first lens; Providing a partial reflector on a side of the first lens close to the light-incident side; Providing a phase retarder on a side of the first lens away from the partial reflector, the phase retarder being configured to change circularly polarized light into linearly polarized light or change linearly polarized light into circularly polarized light; Providing a second lens on a side of the phase retarder away from the first lens; Providing a reflective polarizer on a side of the second lens close to the phase retarder; Providing a light-transmitting structure on a side of the reflective polarizer close to the phase retarder, and the light-transmitting structure is provided with a gap from the phase retarder. Among them, the partial reflector is configured to transmit the light incident from the light incident side, and is configured to reflect the light incident from the phase retarder and change the polarization state of the light. The reflective polarizer has a reflective axis direction and a transmission axis direction that are perpendicular to each other. The reflective polarizer reflects linearly polarized light parallel to the reflective axis direction in the reflective axis direction and keeps the polarization state of the linearly polarized light unchanged. The reflective polarizer transmits linearly polarized light parallel to the transmission axis direction in the transmission axis direction and keeps the polarization state of the linearly polarized light unchanged. The light-transmitting structure has a lowest refraction direction, and the light-transmitting structure has the lowest refractive index for linearly polarized light parallel to the lowest refraction direction in the lowest refraction direction. The included angle between the lowest refraction direction and the reflective axis direction is greater than or equal to 70 degrees and less than or equal to 90 degrees.

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