Polarization splitting module and four-beam polarization splitting system thereof

Abstract

The present application provides a polarization beam splitting module, which is applied to an environment for receiving a pulsed light. The polarization beam splitting module comprises a linear polarizer, a quarter phase retarder, a beam splitter, an air layer, a mirror and an isolation layer. The linear polarizer is used to convert an arbitrary light beam into linearly polarized light. The quarter phase retarder is used to convert the linearly polarized light into circularly polarized light. The beam splitter is used to split a circularly polarized light beam into two left-handed (right-handed) circularly polarized light beams, which have the same phase and intensity and perpendicular traveling directions. The left-handed (right-handed) circularly polarized light is converted into right-handed (left-handed) circularly polarized light after passing through the air layer and the mirror. The mirror is used to change the transmission direction of the light beam. The isolation layer is used to protect the polarization beam splitting module. The present application further provides a four-beam polarization beam splitting system comprising the polarization beam splitting module.

Description

Technical Field

[0001] This invention relates to a polarization beam splitting module, and more particularly to a four-beam polarization beam splitting system that can be easily fabricated using a polarization beam splitting module. Background Technology

[0002] With the evolution of ranging technology, various ranging techniques have been developed and widely applied in applications such as vehicle distance detection, facial recognition, and various Internet of Things (IoT) devices. Common ranging techniques include infrared (IR) ranging, ultrasonic ranging, and intense pulsed light (IPL) ranging. However, as the accuracy requirements for ranging increase, IPL ranging, which employs time-of-flight (ToF) measurement methods, is currently one of the main research directions in this field.

[0003] Time-of-flight (TOF) ranging is an active 3D scanning technology that has been frequently used in recent years, mainly due to its wide measurable distance range, high resolution, and low software complexity, which is conducive to market expansion and technology development. The sensing technology of TOF ranging adds another sensing component capable of measuring depth information to a traditional image sensor. This component calculates depth information by sensing the time change of light reflection and reception.

[0004] Currently, existing time-of-flight ranging (TOF) sensing technologies generally use unpolarized light as the light source. In recent years, sensing technologies using polarized light have been developed. However, this requires two light sources and multiple polarizers to generate two orthogonally polarized light sources as emitted light. The reason for this is that two orthogonally polarized light sources are not affected by ambient light when received by the optical sensor, thus obtaining clearer depth information.

[0005] As smartphones become increasingly thinner and lighter, the number of components that can be placed inside the phone will decrease accordingly. Therefore, how to reduce the number of internal components and the space occupied by these components is one of the problems that researchers should solve. Summary of the Invention

[0006] The purpose of this invention is to provide a polarization beam splitting module that, through simple processing and assembly, can simultaneously generate excitation light in multiple different polarization directions, thereby simplifying and miniaturizing the polarization beam splitting system, further improving its technical performance and reliability, and having extremely important practical significance in the fields of optical testing, optical modulation, optical ranging and other application technologies.

[0007] Another objective of this invention is to provide a four-beam polarization beam splitting system. Through simple processing and combination of polarization beam splitting modules, four different polarization directions of excitation light can be realized. This reduces the ranging and sensing technology, which originally required at least two light sources to generate multiple polarization light sources, to only one light source that can adjust the polarization direction of the excitation light to perform the calculations of ToF sensing technology. This significantly reduces costs and increases system stability.

[0008] To achieve the above objectives, the present invention provides a polarization beam splitting system for use in an environment receiving a pulsed light. The polarization beam splitting module includes: a linear polarizer for converting the pulsed light into linearly polarized light; a quarter-phase retarder disposed on the linear polarizer; a beam splitter disposed on the quarter-phase retarder, the beam splitter having an incident surface, a first emitting surface, and a second emitting surface; an air layer disposed on the quarter-phase retarder and coupled to the second emitting surface; a reflector disposed on the quarter-phase retarder and coupled to the second emitting surface, the reflector being used to reflect the light beam, thereby changing the propagation direction of the light beam and changing the rotation direction of circularly polarized light; and an isolation layer disposed on the beam splitter and the reflector; wherein the pulsed light passes through the linear polarizer. The light is then converted into linearly polarized light with a preset polarization direction. This linearly polarized light with the preset polarization direction is converted into circularly polarized light with a first polarization direction by the quarter-phase retarder. The circularly polarized light with the first polarization direction enters the beam splitter from the incident surface. The beam splitter outputs the circularly polarized light with the first polarization direction, which propagates along a first direction, from the first light-emitting surface to the isolation layer. The beam splitter also outputs the circularly polarized light with the first polarization direction, which propagates along a second direction, from the second light-emitting surface. The circularly polarized light with the first polarization direction passes through the air layer to the reflector and is reflected, changing its polarization direction to form circularly polarized light with a second polarization direction. The circularly polarized light with the second polarization direction changes its propagation direction from the second direction to the first direction and then to the isolation layer.

[0009] Preferably, in the polarization beam splitting module according to the present invention, the linear polarizer is a metal grating.

[0010] Preferably, in the polarization beam splitting module according to the present invention, the first direction is orthogonal to the second direction.

[0011] Preferably, in the polarization beam splitting module according to the present invention, the wavelength of the pulsed light is between 780 nm and 1400 nm.

[0012] Furthermore, to achieve the above objectives, the present invention, based on the aforementioned polarization beam splitting module, further provides a four-beam polarization beam splitting system, comprising: a first polarization beam splitting module for receiving the pulsed light, the first polarization beam splitting module including the aforementioned polarization beam splitting module and a first quarter-phase retarder, the first quarter-phase retarder being disposed on the isolation layer and covering the beam splitter, the first quarter-phase retarder being used to convert circularly polarized light into linearly polarized light; a second polarization beam splitting module coupled to the first polarization beam splitting module, the second polarization beam splitting module including the aforementioned polarization beam splitting module and a second quarter-phase retarder, the second quarter-phase retarder being disposed on the isolation layer and covering the beam splitter and the reflector, the second quarter-phase retarder being used to convert circularly polarized light into linearly polarized light; and A third polarization beam splitter is coupled to the first polarization beam splitter, the third polarization beam splitter including the aforementioned polarization beam splitter; wherein, after receiving the pulse light, the first polarization beam splitter outputs linearly polarized light with a default polarization direction to the second polarization beam splitter, and outputs circularly polarized light with a second polarization direction to the third polarization beam splitter; after receiving the linearly polarized light with a default polarization direction, the second polarization beam splitter outputs the linearly polarized light with a default polarization direction and a linearly polarized light with a third polarization direction; after receiving the circularly polarized light with a second polarization direction, the third polarization beam splitter outputs the circularly polarized light with a first polarization direction and a polarized light with a fourth polarization direction.

[0013] Preferably, in the four-beam polarization beam splitting system according to the present invention, the default polarization direction is orthogonal to the third polarization direction.

[0014] Preferably, in the four-beam polarization beam splitting system according to the present invention, the third polarization beam splitting module further includes a polarizing layer disposed on the isolation layer, the polarizing layer being used to convert circularly polarized light into linearly polarized light.

[0015] Preferably, in the four-beam polarization beam splitting system according to the present invention, the default polarization direction differs from the fourth polarization direction by 45 degrees.

[0016] Therefore, this invention provides a polarization beam splitting module that, through simple processing and assembly, can simultaneously generate excitation light with multiple different polarization directions. This simplifies and miniaturizes the polarization beam splitting system, further improving its technical performance and reliability. It has significant practical implications in optical testing, optical modulation, optical ranging, and other application fields. Furthermore, the linear polarizer and quarter-phase retarder of this polarization beam splitting module can use birefringent polarizers. The advantage of using birefringent polarizers is that, compared to other polarizers, they are less prone to change under high-energy laser irradiation, thus preventing heat accumulation after prolonged high-energy laser irradiation and avoiding deformation, deterioration, and other problems.

[0017] To enable those skilled in the art to understand the purpose, features and effects of the present invention, the present invention will be described in detail below with reference to the following specific embodiments and accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a block diagram of the polarization beam splitting module according to the present invention;

[0019] Figure 2 A schematic diagram illustrating specific details of the polarization beam splitting module according to the present invention;

[0020] Figure 3 A schematic diagram illustrating the polarization beam splitting module of the present invention receiving incident light from the external environment;

[0021] Figures 4 to 6 These are schematic diagrams illustrating various other exemplary polarization beam splitting modules;

[0022] Figure 7 The diagram below illustrates a four-beam polarization beam splitting system.

[0023] Explanation of reference numerals in the attached figures:

[0024] 100, 100A, 100B, 100C - Polarization beam splitting modules;

[0025] 11, 11A, 11B, 11C - Linear polarizers;

[0026] 12, 12A, 12B, 12C - Quarter-phase delay films;

[0027] 121 - First quarter-phase delay plate;

[0028] 122 - Second quarter-phase delay plate;

[0029] 13, 13A, 13B, 13C - Beam splitters;

[0030] 131 - Incident surface;

[0031] 132 - First light-emitting surface;

[0032] 133 - Second light-emitting surface;

[0033] 14, 14A, 14B, 14C - Reflecting mirrors;

[0034] 15, 15A, 15B, 15C - Isolation layers;

[0035] 16-Air layer;

[0036] 17-Polarizing layer;

[0037] A - Preset polarization direction;

[0038] A1 - First polarization direction;

[0039] A2 - Second polarization direction;

[0040] A3 - Third polarization direction;

[0041] A4 - Fourth polarization direction;

[0042] L-linearly polarized light;

[0043] Lc - Circularly polarized light;

[0044] Lcl - Left-handed polarized light;

[0045] Lcr - Right-handed polarized light;

[0046] PL - Pulsed light;

[0047] X - First direction;

[0048] Y - Second direction. Detailed Implementation

[0049] The inventive concept will now be more fully described below with reference to the accompanying drawings, which illustrate exemplary embodiments of the inventive concept. The advantages and features of the inventive concept, as well as methods of achieving it, will become apparent from the exemplary embodiments described in more detail below with reference to the accompanying drawings. However, it should be noted that the inventive concept is not limited to the exemplary embodiments described below, but can be implemented in various forms. Therefore, exemplary embodiments are provided only to disclose the inventive concept and to enable those skilled in the art to understand the category of the inventive concept. In the drawings, exemplary embodiments of the inventive concept are not limited to the specific instances provided herein and are exaggerated for clarity.

[0050] The terminology used herein is for illustrative purposes only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular forms of the terms “a” and “the” as used herein are intended to include the plural forms as well. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. It should be understood that when a component is referred to as “connected” or “coupled” to another component, the component may be directly connected or coupled to the other component or there may be intermediate components.

[0051] Similarly, it should be understood that when a component (e.g., a layer, region, or substrate) is said to be "on" another component, the component may be directly on the other component, or there may be intermediate components. In contrast, the term "directly" implies the absence of intermediate components. Furthermore, it should be understood that when the terms "comprising" or "including" are used herein, they indicate the presence of the stated features, integers, steps, operations, components, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, components, and / or groups thereof.

[0052] Furthermore, exemplary embodiments in the detailed description will be illustrated by cross-sectional views of idealized exemplary drawings that serve as concepts of the present invention. Accordingly, the shapes of the exemplary drawings may be modified according to manufacturing techniques and / or tolerable errors. Therefore, exemplary embodiments of the present invention are not limited to the specific shapes shown in the exemplary drawings, but may include other shapes that may be produced according to the manufacturing process. The areas illustrated in the drawings have general characteristics and are used to illustrate specific shapes of components. Therefore, this should not be considered as limiting the scope of the present invention.

[0053] It should also be understood that although terms such as "first," "second," and "third" may be used herein to describe various components, these components should not be limited to these terms. These terms are only used to distinguish the various components. Therefore, a first component in some embodiments may be referred to as a second component in other embodiments, without departing from the teachings of the invention. Exemplary embodiments of the inventive concepts illustrated and described herein include their complementary counterparts. Throughout this specification, the same reference numerals or the same indicators denote the same components.

[0054] Furthermore, exemplary embodiments are described herein with reference to sectional views and / or plan views, which are idealized illustrative diagrams. Therefore, deviations from the illustrated shapes are expected due to factors such as manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the areas shown herein, but are intended to include shape deviations caused, for example, by manufacturing processes. Therefore, the areas shown in the figures are schematic and their shapes are not intended to illustrate the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0055] Please see Figure 1-3 , Figure 1 This is a block diagram of the polarization beam splitting module according to the present invention; Figure 2 A schematic diagram illustrating specific details of the polarization beam splitting module according to the present invention; Figure 3 This is a schematic diagram illustrating the polarization beam splitting module of the present invention receiving incident light from the external environment. (See diagram below.) Figure 1 As shown, the polarization beam splitter 100 according to the present invention is applied in an environment receiving pulsed light Lp. The polarization beam splitter 100 includes: a linear polarizer 11, a quarter-phase delay film 12, a beam splitter 13, a reflector 14, an isolation layer 15, and an air layer 16.

[0056] Specifically, such as Figure 1 and Figure 2 As shown, the linear polarizer 11 according to the present invention is used to convert any light beam into linearly polarized light L, wherein the linear polarizer 11 converts the incident pulse light Lp into linearly polarized light L with a predetermined polarization direction D. Specifically, in some embodiments, the linear polarizer 11 is a metal grating. For example, the linear polarizer 11 can be fabricated as a half-wave plate in the megahertz band using a complementary metal grating structure. Metal meshes with capacitive and inductive properties are stacked perpendicularly to each other, so that the electric field components of the incident pulse light Lp undergo different phase changes along these two directions, thereby changing the polarization state of the pulse light Lp. For details, please refer to... Figure 3 As shown, in some embodiments, the wavelength range of the pulsed light Lp is the infrared wavelength range; more specifically, the wavelength range of the pulsed light Lp is between 780 nm and 1400 nm. Furthermore, the linear polarizer 11 converts the incident pulsed light Lp into horizontally linearly polarized light L1, wherein the preset polarization direction D is the horizontal polarization direction; however, the present invention is not limited thereto.

[0057] Specifically, such as Figure 1 and Figure 2As shown, the quarter-phase retarder 12 according to the present invention is disposed on the linear polarizer 11. The quarter-phase retarder 12 is used to convert linearly polarized light L into circularly polarized light Lc. Specifically, the quarter-phase retarder 12 converts linearly polarized light L with a preset polarization direction D into circularly polarized light Lc with a first polarization direction D1. In some embodiments, the quarter-phase retarder 12 can be one of a reflective, dichroic, or birefringent polarizer. Preferably, the quarter-phase retarder 12 can use a birefringent crystal. The advantage of using a birefringent crystal is that, compared to other polarizers, it is less prone to change under high-energy laser irradiation, thus preventing heat accumulation after prolonged high-energy laser irradiation, which could lead to deformation, deterioration, and other problems. Therefore, the quarter-phase retarder 12 according to the present invention can use a birefringent crystal to convert linearly polarized light L into circularly polarized light Lc. For details, please refer to... Figure 3 As shown, in this embodiment, the quarter-phase delay plate 12 can be a quarter-wave plate (QWP), so that after the horizontally linearly polarized light L1 is incident on the quarter-phase delay plate 12, the quarter-phase delay plate 12 converts the horizontally linearly polarized light L1 into right-handed polarized light Lcr, wherein the first polarization direction D1 is the right-handed polarization direction. However, the present invention is not limited to this.

[0058] Specifically, such as Figure 1 and Figure 2 As shown, the beam splitter 13 according to the present invention is disposed on a quarter-phase retarder 12. The beam splitter 13 has an incident surface 131, a first emitting surface 132, and a second emitting surface 133. Circularly polarized light Lc with a first polarization direction D1 enters the beam splitter 13 from the incident surface 131. The beam splitter 13 outputs circularly polarized light Lc with a first polarization direction D1, propagating along a first direction X, to the isolation layer 15 from the first emitting surface 132. The beam splitter 13 also outputs circularly polarized light Lc with a first polarization direction D1, propagating along a second direction Y, from the second emitting surface 133. Specifically, in some embodiments, the beam splitter 13 can be a birefringent polarizing device made of natural calcite crystal, employing a double-reflection structure design. It utilizes total internal double reflection of incident light at the crystal interface to change the polarization direction and split the beam, thereby achieving the integrated function of changing the polarization direction, splitting the beam, and directing the beam through the beam splitter 13. For details, please refer to [link to relevant documentation]. Figure 3 As shown, in some embodiments, the right-handed polarized light Lcr is converted by the beam splitter 13 into right-handed polarized light Lcr propagating along the first direction X to the isolation layer 15, and right-handed polarized light Lcr propagating along the second direction Y to the air layer 16; however, the present invention is not limited thereto.

[0059] Specifically, such as Figure 1 and Figure 2 As shown, according to the present invention, the air layer 16 is disposed on the quarter-phase retarder 12 and coupled to the second light-emitting surface 133. Specifically, in some embodiments, the refractive index of the air layer 16 is less than that of the reflector 14, so that the air layer 16 is an optically less dense medium relative to the reflector 14, causing the beam to undergo a change in polarization direction after being transmitted from the air layer 16 to the reflector 14, forming reflected light orthogonal to the original beam polarization direction.

[0060] Specifically, such as Figure 1 and Figure 2 As shown, according to the present invention, the reflector 14 is disposed on the quarter-phase delay plate 12 and coupled to the second light-emitting surface 133. The reflector 14 is used to reflect the light beam, thereby changing the propagation direction of the light beam. Specifically, please refer to... Figure 2 and Figure 3 As shown, in some embodiments, right-handed polarized light Lcr propagating along the second direction Y is transmitted to the reflector 14 and forms circularly polarized light Lc propagating along the second direction Y with a second polarization direction D2, wherein the second polarization direction D2 is a left-handed polarization direction, so that the right-handed polarized light Lcr originally propagating along the second direction Y is converted into left-handed polarized light Lcl propagating along the first direction X to the isolation layer 15. Specifically, in some embodiments, the first polarization direction D1 and the second polarization direction D2 are orthogonal to each other; however, the present invention is not limited thereto.

[0061] Specifically, such as Figure 1 and Figure 2 As shown, according to the present invention, the isolation layer 15 is disposed on the uppermost layer of the polarization beam splitter module 100. More specifically, when there are multiple polarization beam splitter modules 100, it is disposed between the polarization beam splitter modules 100. Thus, in some embodiments, the isolation layer 15 can serve as an isolation structure between multiple polarization beam splitter modules 100. In this invention, the term "isolation" encompasses both electrical isolation and physical isolation. The isolation layer 15 can be a single layer of inorganic encapsulation material, a multilayer stack of inorganic encapsulation materials, or a stack of pairs of inorganic encapsulation materials and organic encapsulation materials. The inorganic encapsulation materials used are, for example, but not limited to, silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiONx), aluminum oxide (AlOx), or titanium oxide (TiOx).

[0062] It is worth mentioning that the isolation layer 15 of the polarization beam splitting module 100 according to the present invention can be directly used as a substrate for other polarizers without the need for additional substrates. Furthermore, users can directly perform simple processing on the isolation layer 15 to achieve excitation light with different polarization directions. This allows the present invention to achieve a thinner polarization beam splitting module 100 while also having wide applicability.

[0063] Therefore, this invention provides a polarization beam splitter module 100, which, through simple processing and assembly, can simultaneously generate excitation light with multiple different polarization directions. This simplifies and thins the polarization beam splitter system, further improving its technical performance and reliability. It has significant practical implications in optical testing, optical modulation, optical ranging, and other application fields. Furthermore, the linear polarizer 11 and quarter-phase retarder 12 of the polarization beam splitter module 100, by using birefringent polarizers, are less prone to change under high-energy laser irradiation, thus preventing heat accumulation after prolonged high-energy laser irradiation and avoiding problems such as deformation and deterioration.

[0064] Other examples of polarization beam splitting modules are provided below to enable those skilled in the art to more clearly understand possible variations. Components indicated by the same component symbols as in the above embodiments are substantially the same as those referenced above. Figure 1 , Figure 2 The components, features, and advantages that are the same as those of the polarization beam splitter module 100 will not be repeated.

[0065] Please refer to Figure 4 The diagram illustrates an illustrative first polarization beam splitter module 100A. The first polarization beam splitter module 100A differs from the polarization beam splitter module 100 in that it further includes a first quarter-phase retarder 121. This first quarter-phase retarder 121 is disposed on the isolation layer 15A and covers the beam splitter 13A. The first quarter-phase retarder 121 is used to convert circularly polarized light into linearly polarized light. Specifically, in some embodiments, after receiving pulsed light Lp, the first polarization beam splitter module 100A outputs linearly polarized light with a default polarization direction D and circularly polarized light with a second polarization direction D2. The linearly polarized light with the default polarization direction D is horizontally linearly polarized light L1, and the circularly polarized light with the second polarization direction D2 is left-handedly polarized light Lcl. However, the invention is not limited to this.

[0066] Please refer to Figure 5The diagram illustrates an illustrative second polarization beam splitter module 100B. The second polarization beam splitter module 100B differs from the polarization beam splitter module 100 in that it further includes a second quarter-phase retarder 122. The second quarter-phase retarder 122 is disposed on the isolation layer 15B and covers the beam splitter 13B and the reflector 14B. The second quarter-phase retarder 122 is used to convert circularly polarized light into linearly polarized light. Specifically, in some embodiments, after the second polarization beam splitter 100B receives linearly polarized light with a default polarization direction D, the second polarization beam splitter 100B outputs linearly polarized light with a default polarization direction D and linearly polarized light with a third polarization direction D3. The quarter-wave delay plate 12B can be a quarter-wave plate, and the polarization direction D and the third polarization direction D3 are orthogonal to each other. In this way, the linearly polarized light with polarization direction D is the horizontally polarized light L1, and the linearly polarized light with the third polarization direction D3 is the vertically polarized light L2. However, the present invention is not limited to this.

[0067] It should be further explained that, compared with the polarization beam splitter module 100, the beam splitter 13B and the reflector 14B of the second polarization beam splitter module 100B are mirror-symmetric with the beam splitter 13 and the reflector 14 of the polarization beam splitter module 100. The mirror symmetry can be achieved by simply flipping the polarization beam splitter module 100 horizontally by 180 degrees and then placing the second quarter-phase delay film 122 on the isolation layer 15B to generate the second polarization beam splitter module 100B. However, the present invention is not limited to this.

[0068] Please refer to Figure 6 The diagram illustrates a polarization beam splitter module 100C. The third polarization beam splitter module 100C differs from the polarization beam splitter module 100 in that it further includes a polarizing layer 17, which is disposed on the isolation layer 15C and covers the reflector 14C. The polarizing layer 17 is used to convert circularly polarized light into linearly polarized light. Specifically, in some embodiments, after the third polarization beam splitter 100C receives circularly polarized light with the second polarization direction D2, the third polarization beam splitter 100C outputs circularly polarized light with the first polarization direction D1 and linearly polarized light with the fourth polarization direction D4. The circularly polarized light with the first polarization direction D1 is right-handed polarized light Lcr, and the polarizing layer 17 can be a polarizer with any polarization direction. In this embodiment, the fourth polarization direction D4 is 45 degrees away from the preset polarization direction D. However, the linearly polarized light with the fourth polarization direction D4 can be linearly polarized light with any polarization angle and does not need to be particularly limited.

[0069] It is understood that those skilled in the art to which this invention pertains can make various changes and adjustments based on the above examples, which will not be listed here. The focus here will be on the application of the four-beam polarization beam splitting system according to the embodiments.

[0070] Please see Figure 7 The illustration shows a four-beam polarization beam splitter system 10. For example... Figure 6 As shown, according to the present invention, the four-beam polarization beam splitting system 10, using the embodiment described above, includes: a first polarization beam splitting module 100A, a second polarization beam splitting module 100B, and a third polarization beam splitting module 100C.

[0071] To further understand the structural features, technical means, and expected effects of the present invention, the actual implementation process of the present invention is described below, which will provide a deeper and more specific understanding of the present invention:

[0072] Specifically, please refer to Figure 7 As shown, the actual beam splitting process of the four-beam polarization beam splitting system 10 according to the present invention is described as follows: First, the first polarization beam splitting module 100A receives the pulse light Lp, and outputs horizontally linearly polarized light L1 to the second polarization beam splitting module 100B, and outputs left-handedly polarized light Lcl to the third polarization beam splitting module 100C; then, the second polarization beam splitting module 100B receives the horizontally linearly polarized light L1, and outputs horizontally linearly polarized light L1 with a default polarization direction D and vertically linearly polarized light L2 with a third polarization direction D3; simultaneously, the third polarization beam splitting module 100C receives left-handedly polarized light Lcl, and outputs right-handedly polarized light Lcr with a first polarization direction D1 and linearly polarized light with a fourth polarization direction D4.

[0073] Therefore, this invention can realize four different polarization directions of excitation light through simple processing and combination of polarization beam splitting module 100. The ranging and sensing technology that originally required at least two light sources to generate multiple polarization light sources can be reduced to only one light source that can adjust the polarization direction of the excitation light to perform the calculation of ToF sensing technology, which greatly reduces the cost and increases the stability of the system.

[0074] It is worth mentioning that, according to the present invention, the four-beam polarization beam splitting system 10 can be processed and combined in different ways with the polarization beam splitting module 100 to achieve excitation light with four different polarization directions. The polarization direction of the polarized light output by the four-beam polarization beam splitting system 10 can be adjusted according to the user's needs. For example, when the third polarization beam splitting module 100C does not have the polarizing layer 17, the polarized light output by the four-beam polarization beam splitting system 10 will be horizontally linearly polarized light L1, vertically linearly polarized light L2, right-handedly polarized light Lcr, and left-handedly polarized light Lcl. Furthermore, as more polarization beam splitting modules 100 are processed and combined in different ways, the polarization beam splitting module 100 of the present invention can realize a six-beam polarization beam splitting system or an eight-beam polarization beam splitting system. It is understood that those skilled in the art can make various changes and adjustments based on the above examples, which will not be listed here.

[0075] Finally, the technical features of this invention and the technical effects it can achieve are summarized as follows:

[0076] Firstly, this invention provides a polarization beam splitting module 100, which can simultaneously generate excitation light with multiple different polarization directions through simple processing and assembly. This simplifies and thins the polarization beam splitting system, further improving its technical performance and reliability. It has extremely important practical significance in application fields such as optical testing, optical modulation, and optical ranging.

[0077] Secondly, the linear polarizer 11 and quarter-phase delay film 12 of the polarization beam splitter 100 according to the present invention are less prone to change under high-energy laser irradiation by using birefringent polarizers, thereby achieving the effect of preventing heat accumulation after long-term high-energy laser irradiation and preventing deformation, deterioration and other problems.

[0078] Third, this invention can achieve excitation light with four different polarization directions through simple processing and combination of polarization beam splitting module 100. The ranging and sensing technology that originally required at least two light sources to generate multiple polarization light sources can be reduced to only one light source that can adjust the polarization direction of the excitation light to perform the calculation of ToF sensing technology, which greatly reduces the cost and increases the stability of the system.

[0079] The above description of specific embodiments illustrates the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0080] The above describes the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A polarization splitting module, characterized in that, The application is applied to a pulsed light receiving environment, comprising: a linear polarizer, used for converting the pulsed light into linearly polarized light; a quarter phase retarder, disposed on the linear polarizer; a beam splitter, disposed on the quarter phase retarder, having an incident surface, a first light output surface, and a second light output surface; an air layer, disposed on the quarter phase retarder and coupled to the second light output surface; a mirror, disposed on the quarter phase retarder and coupled to the air layer, used for reflecting the light beam to change the transmission direction of the light beam and the rotation direction of the circularly polarized light; and an isolation layer, disposed on the beam splitter and the mirror; wherein the pulsed light is converted into linearly polarized light with a preset polarization direction after passing through the linear polarizer, the linearly polarized light with the preset polarization direction is converted into circularly polarized light with a first polarization direction after passing through the quarter phase retarder, the circularly polarized light with the first polarization direction enters the beam splitter from the incident surface, the beam splitter outputs the circularly polarized light with the first polarization direction transmitted in a first direction from the first light output surface to the isolation layer, and the beam splitter outputs the circularly polarized light with the first polarization direction transmitted in a second direction from the second light output surface, the circularly polarized light with the first polarization direction is reflected after passing through the air layer to the mirror, and the polarization direction is changed to form circularly polarized light with a second polarization direction, the circularly polarized light with the second polarization direction is transmitted from the second direction to the first direction to the isolation layer.

2. The polarization splitting module according to claim 1, characterized in that, The linear polarizer is a metal grating.

3. The polarization splitting module according to claim 1, characterized in that, The first direction is orthogonal to the second direction.

4. The polarization splitting module according to claim 1, characterized in that, The wavelength of the pulsed light is between 780 nm and 1400 nm.

5. A four-beam polarization spectroscopy system, characterized by, comprising: a first polarization beam splitting module, used for receiving the pulsed light, the first polarization beam splitting module comprising the polarization beam splitting module of claim 1 and a first quarter phase retarder, the first quarter phase retarder being disposed on the isolation layer and covering the beam splitter, the first quarter phase retarder being used for converting circularly polarized light into linearly polarized light; a second polarization beam splitting module, coupled to the first polarization beam splitting module, the second polarization beam splitting module comprising the polarization beam splitting module of claim 1 and a second quarter phase retarder, the second quarter phase retarder being disposed on the isolation layer and covering the beam splitter and the mirror, the second quarter phase retarder being used for converting circularly polarized light into linearly polarized light; and a third polarization beam splitting module, coupled to the first polarization beam splitting module, the third polarization beam splitting module comprising the polarization beam splitting module of claim 1. The first polarized light splitting module receives the pulsed light, and outputs linearly polarized light with a default polarization direction to the second polarized light splitting module, and outputs circularly polarized light with a second polarization direction to the third polarized light splitting module. The second polarized light splitting module receives the linearly polarized light with the default polarization direction, and outputs the linearly polarized light with the default polarization direction and linearly polarized light with a third polarization direction. The third polarized light splitting module receives the circularly polarized light with the second polarization direction, and outputs circularly polarized light with a first polarization direction and polarized light with a fourth polarization direction.

6. The four-beam polarization spectroscopic system of claim 5, wherein, The default polarization direction and the third polarization direction are orthogonal to each other.

7. The four-beam polarization spectroscopic system of claim 5, wherein, The third polarized light splitting module further includes a polarizing layer disposed on the isolation layer, and the polarizing layer is used to convert circularly polarized light into linearly polarized light.

8. The four-beam polarization spectroscopic system of claim 7, wherein, The default polarization direction and the fourth polarization direction are different by 45 degrees.

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