Light modulation element
By designing a microlens array on the light-emitting side of the optical modulation element, the problem of insufficient output energy when the beam is not incident perpendicularly is solved, and the maximum output energy of the beam is achieved when it is not incident perpendicularly, thus expanding the applicable range and optimizing the energy distribution.
Patent Information
- Application Number
- CN202423233452.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2034-12-26
AI Technical Summary
Existing optical modulation elements cannot achieve maximum output energy when the beam is not incident perpendicularly, which cannot meet the needs of special scenarios.
Design an optical modulation element with a microlens array on its light-emitting side. The microlens is a closed shape with right-angled sides, which is rotated 360° around the straight line containing the right-angled sides as the rotation axis. By modulating the incident angle of the light beam, the emitted energy of the light beam is maximized when it is not perpendicularly incident.
It achieves maximum output energy of the beam when it is not perpendicularly incident, expands the applicable range of the optical modulation element, and ensures that the output energy reaches the peak value in the entire incident range through total internal reflection and energy peak shift of the detection plane.
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Figure CN223526524U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of optics, in particular to an optical modulation element. BACKGROUND
[0002] In the field of optics, an optical modulation element is usually used to modulate a light beam, which has an incident surface and an exit surface arranged oppositely, and the light beam is incident from the incident surface and exits from the exit surface. Generally speaking, the exit energy of the light beam is the largest when the light beam is incident perpendicularly to the incident surface; however, in some special scenarios, the exit energy of the light beam needs to be the largest when the light beam is incident non-perpendicularly. Therefore, it is currently an urgent problem in the field to design an optical modulation element capable of making the exit energy of the light beam the largest when the light beam is incident non-perpendicularly. SUMMARY
[0003] To solve the above problems, the present application provides an optical modulation element capable of making the exit energy of the light beam the largest when the light beam is incident non-perpendicularly.
[0004] An optical modulation element has an incident side and an exit side arranged oppositely, wherein a light beam is incident from an incident surface of the incident side, and the incident angle is the angle between the incident direction and the normal line of the incident surface; the exit side has a microstructure and is a micro-lens array, the micro-lens in the micro-lens array is a closed shape with a right angle side, and the micro-lens is formed by rotating the closed shape with the straight line of the right angle side as the rotation axis by 360°, so that when the exit energy of the light beam after exiting from the exit side is detected on a detection plane, the corresponding incident angle when the exit energy is the largest is not zero; wherein the detection plane is parallel to the incident surface.
[0005] In an implementation, when the light beam is incident from the incident surface, the angle between the incident direction and the normal line of the incident surface is an initial incident angle; when the light beam is incident to a structure surface of the micro-lens, the angle between the incident direction and the normal line of the structure surface is an intermediate incident angle; the initial incident angle corresponding to the light beam when the exit energy is the largest is a target angle; wherein the intermediate incident angle corresponding to the light beam with the initial incident angle smaller than the target angle is greater than or equal to the total reflection critical angle of the light beam exiting from the structure surface, or the detection incident angle of the light beam with the initial incident angle smaller than the target angle incident to the detection plane is greater than the optimal detection angle, so that the target angle is not zero.
[0006] In an implementation, the initial incident angle θ1 and the intermediate incident angle θ5 satisfy the following formula:
[0007] θ1=arcsin((n3 / n1)*sin(α-θ5))
[0008] When θ1<θ T , θ5≥θ C , θC = arcsin(n4 / n3);
[0009] wherein, n1 is the refractive index of the external medium of the light modulation element, n3 is the refractive index of the microlens array, n4 is the refractive index of the external medium of the microlens, a is the included angle between the tangent of the position of the light beam incident to the microlens structure surface and the non-structure surface of the microlens, θ T is the target angle, θ C is the critical angle of total reflection.
[0010] In an embodiment, the initial incident angle θ1 and the probe incident angle θ7 satisfy the following formula:
[0011]
[0012] When θ1 < θ T , θ7 > θ D .
[0013] wherein, n1 is the refractive index of the external medium of the light modulation element, n3 is the refractive index of the microlens array, n4 is the refractive index of the external medium of the microlens, a is the included angle between the tangent of the position of the light beam incident to the microlens structure surface and the non-structure surface of the microlens, θ T is the target angle, θ D is the optimal probe angle.
[0014] In an embodiment, the optimal probe angle ranges from 3° to 5°.
[0015] In an embodiment, the straight line of the closed shape is a straight line, a multi-segment broken line, a curve or a multi-segment curve.
[0016] In an embodiment, the incident angle at which the exit energy is the highest ranges from 0° to 55°.
[0017] In an embodiment, the light modulation element comprises a light-transmitting substrate, the surface of the light-transmitting substrate is provided with the microlens array, the side of the microlens array away from the light-transmitting substrate is provided with a filling layer, and the surface of the side of the filling layer facing outward is flat.
[0018] In an embodiment, the refractive index of the microlens array is greater than the refractive index of the filling layer.
[0019] In an embodiment, the refractive index of the light-transmitting substrate is greater than the refractive index of the filling layer and less than the refractive index of the microlens array.
[0020] The application provides a light modulation element, which has an incident light side and an emergent light side arranged oppositely, wherein the emergent light side has a microstructure and is a microlens array, and the microlens in the microlens array is designed to have a closed shape with a right-angle side, and the microlens is rotated 360° around a straight line where the right-angle side is located to form a geometric body, so that the light beam can be modulated by the structure surface of the microlens when the light beam is incident to the structure surface of the microlens, and the maximum emergent energy of the light beam at the expected incident angle can be achieved.
[0021] Further, the initial incident angle corresponding to the maximum emergent energy of the light beam is set as a target angle, for the light beam with the initial incident angle smaller than the target angle, the incident angle of the light beam to the structure surface of the microlens is greater than or equal to the total reflection critical angle of the light beam from the structure surface, or the detection incident angle of the light beam to the detection plane is greater than the optimal detection angle, so that the light beam can be totally reflected in the microlens array or be incident to the detection plane with a larger emergent angle, thereby the energy peak detected by the detection plane can be shifted, and the target angle can be set to be not zero. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.
[0023] Figure 1 A structural schematic diagram of a light modulation element provided by the embodiment of the present application is shown in the figure.
[0024] Figure 2 A light path schematic diagram of a light modulation element provided by the embodiment of the present application is shown in the figure.
[0025] Figure 3 A schematic diagram of a closed shape forming a microlens shape structure provided by the embodiment of the present application is shown in the figure.
[0026] Figure 4 A structural schematic diagram of another light modulation element provided by the embodiment of the present application is shown in the figure.
[0027] Figure 5 A light path schematic diagram of another light modulation element provided by the embodiment of the present application is shown in the figure.
[0028] IDENTIFICATION OF DRAWINGS
[0029] 100: light modulation element;
[0030] 101: incident light side;
[0031] 102: emergent light side;
[0032] 110: transparent substrate;
[0033] 120: microlens array;
[0034] 130: filling layer;
[0035] 140: detection plane. DETAILED DESCRIPTION
[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0037] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments.
[0038] The present application provides a light modulation element, which has an opposite light entrance side and a light exit side, characterized in that a light beam is incident from a light entrance surface of the light entrance side, and the incident angle is the angle between the incident direction and the normal line of the light entrance surface; the light exit side has a microstructure and is a microlens array, the microlens in the microlens array is a closed shape with a right angle edge, and the straight line where the right angle edge is located is the rotation axis, and the geometric body formed by rotating 360°, so that when the detection plane detects the exit energy of the light beam after exiting from the light exit side, the corresponding incident angle of the highest exit energy is not zero; wherein the detection plane is parallel to the light entrance surface.
[0039] In the present application, the light modulation element is a sheet-shaped structure or a plate-shaped structure, and the material of the light modulation element can be an organic or inorganic material including but not limited to glass and resin.
[0040] Specifically, the light beam is incident from the light entrance side of the light modulation element to the light modulation element, and then exits from the light exit side of the light modulation element. Since the light exit side of the light modulation element has a microstructure, which is specifically a microlens array, the shape structure of the microlens array can modulate the exit energy distribution of the light beam under different incident angles when certain conditions are met, so that by optimizing the parameters of the microlens array shape structure, the incident angle corresponding to the exit energy peak value can be changed, so that the light beam can achieve the maximum exit energy when it is incident at the expected incident angle. Of course, in another embodiment, other parameters such as the refractive index of the material of the light modulation element can also be optimized alone or cooperatively to change the incident angle corresponding to the exit energy peak value.
[0041] ReferenceFigure 1 The optical modulation element 100 has an incident light side 101 and an emitted light side 102 arranged opposite to each other. The emitted light side 102 has a microstructure, which can be specifically implemented as a microlens array. Each microlens in the microlens array is a closed shape with right-angled sides, formed by rotating 360° around the line containing the right-angled sides as the axis of rotation. The closed shape with right-angled sides can be defined by the dimensions of the two right-angled sides, and the shape and structural parameters of the microlens can be defined by the height H and the width W. The height H is the dimension of one right-angled side of the closed shape, and the dimension of the other right-angled side is half the width W.
[0042] In practice, when the light beam is incident from the incident surface on the incident side, the angle between the incident direction and the normal of the incident surface is the initial incident angle; when the light beam is transmitted inside the optical modulation element and incident on the structural surface of the microlens, the angle between the incident direction and the normal of the structural surface is the intermediate incident angle; the initial incident angle when the light beam has the highest output energy is the target angle; wherein, the intermediate incident angle corresponding to the light beam with an initial incident angle less than the target angle can be greater than or equal to the critical angle of total internal reflection of the light beam exiting from the optical modulation element, or, the detection incident angle of the light beam with an initial incident angle less than the target angle incident on the detection plane is greater than the optimal detection angle, so that the target angle is not zero.
[0043] Continue to refer to Figure 1 When the light beam is incident from the incident side 101, the angle between the incident direction and the normal to the incident surface is the initial incident angle θ. When the light beam is incident to the exit side 102, the exit surface is the structural surface of the microlens, and the angle between the incident direction and the normal to the structural surface is the intermediate incident angle. The angle between the incident direction and the normal to the detection plane is the detection incident angle δ. When θ is less than the target angle, the beam corresponding to... When the angle is greater than or equal to the critical angle for total internal reflection of the beam exiting the structural surface, total internal reflection can occur within the microlens array, thus shifting the energy peak detected on the detection plane. Similarly, when δ corresponds to a beam with θ less than the target angle and is greater than the optimal detection angle, the energy peak detected on the detection plane can also shift, ensuring the target angle is not zero. It should be noted that... Figure 1 The distance between the detection plane 400 and the optical modulation element is for illustrative purposes only and does not constitute any limitation on this application.
[0044] That is, for a beam whose θ is less than the target angle, either its corresponding... The critical angle of total reflection of the light beam exiting the structure surface is greater than or equal to the optimal detection angle, or the corresponding δ is greater than the optimal detection angle. It should be noted that when the light beam is incident at different angles, the exiting energy detected by the detection plane will be different due to the change of the exiting angle. In this application, it is intended that when the light beam is incident on the light-in surface of the light modulation element at a non-zero target angle, the exiting energy is higher than that when the light beam is incident on the light-in surface of the light modulation element at other angles, i.e., the exiting energy reaches the highest in the full incidence range.
[0045] Generally, when the detection plane detects energy, the energy detected when the light beam is normally incident on the detection plane is the maximum, and the energy that can be detected gradually decreases as the incidence angle increases. In this application, since the intermediate incidence angle corresponding to the light beam with an initial incidence angle smaller than the target angle is greater than or equal to the critical angle of total reflection of the light beam exiting the light modulation element, i.e., the light beam with an incidence angle smaller than the target angle is totally reflected on the structure surface of the microlens, the peak of the energy detected by the detection plane is shifted, so that the target angle is the peak position of the exiting energy in the full incidence range. Alternatively, the detection incidence angle of the light beam with an initial incidence angle smaller than the target angle incident on the detection plane is greater than the optimal detection angle, which causes the peak of the energy detected by the detection plane to shift, so that the target angle is the peak position of the exiting energy in the full incidence range.
[0046] In an embodiment, the light modulation element comprises a light-transmitting substrate and a microlens array arranged on one side surface of the light-transmitting substrate. The other side surface of the light-transmitting substrate is a plane and is a light-in surface, and the outer side surface of the microlens array is a structure surface and is a light-out surface.
[0047] Further, in an embodiment, the initial incidence angle θ1 and the intermediate incidence angle θ5 satisfy the following formula:
[0048] θ1 = arcsin ((n3 / n1) * sin (α-θ5))
[0049] When θ1 < θ T , θ5 ≥ θ C , and θ C = arcsin (n4 / n3).
[0050] Wherein, n1 is the refractive index of the external medium of the light modulation element, n3 is the refractive index of the microlens array, n4 is the refractive index of the external medium of the microlens, α is the included angle between the tangent at the incidence position of the light beam incident on the structure surface and the non-structure surface of the microlens, θ T is the target angle, and θ C is the critical angle of total reflection.
[0051] Reference Figure 2The light beam is incident to the light entrance surface (one side surface of the light-transmissive substrate) of the light modulation element from the external medium (refractive index n1) at an incident angle θ1, is refracted and enters the light-transmissive substrate 110 (refractive index n2) at an angle θ2. The light beam continues to transmit in the light-transmissive substrate 110 to the other side surface at an incident angle θ3, is refracted and enters the microlens array 120 (refractive index n3) at an angle θ4. The light beam continues to transmit in the microlens array 120 to the structure surface at an incident angle θ5, is refracted and enters the external medium (refractive index n4) at an angle θ6.
[0052] wherein θ T is the angle value of the initial incident angle at which the light beam has the highest exit energy, and θ T is the angle value of the initial incident angle at which the light beam has the lowest exit energy. T
[0053] In an embodiment, the initial incident angle θ1 and the detection incident angle θ7 satisfy the following formula:
[0054]
[0055] When θ1<θ T , θ7>θ D .
[0056] wherein n1 is the refractive index of the external medium of the light modulation element, n3 is the refractive index of the microlens array, n4 is the refractive index of the external medium of the microlens, α is the included angle between the tangent at the incident position of the light beam to the structure surface and the non-structure surface of the microlens, θ T is the target angle, and θ D is the optimal detection angle.
[0057] In an embodiment, the optimal detection angle is in the range of 3°-5°.
[0058] With reference to Figure 2 , the light beam exits from the microlens array and enters the external medium, and then is incident to the detection plane at an incident angle θ7, wherein θ T is the angle value of the initial incident angle at which the light beam has the highest exit energy, and θ D is the optimal detection angle, so that the light beam with the initial incident angle less than θ T deviates from the optimal detection angle when incident to the detection surface, so that the energy peak value detected in the detection plane is shifted, and the peak position of the exit energy in the full incident range is shifted from the incident angle 0° of the vertical incidence to θ T .
[0059] In an embodiment, the incident angle at which the highest energy is emitted ranges from 0° to 55°. It can be understood that, in the present application, the peak position of the emitted energy in the full incident range is shifted from the normal incidence (i.e. the incident angle of 0°) to the direction of increasing incident angle by designing the surface shape parameters of the microlens. The present application can achieve a shift of at least 55°, i.e. the peak position of the emitted energy is shifted to the incident angle of 55°.
[0060] In the present application, the microlenses in the microlens array are geometric bodies formed by rotating a closed shape with a right angle side by 360° about the straight line on which the right angle side lies. The connecting line of the right angle side of the closed shape can be a straight line, a multi-segment broken line, a curve or a multi-segment curve, etc. Referring to Figure 3 , the figure exemplarily shows the schematic diagrams of several closed shapes that can be achieved by the present application, but does not limit the scope of protection claimed by the present application.
[0061] In another embodiment, the light modulating element includes a light-transmitting substrate, a surface of the light-transmitting substrate is provided with a microlens array, a filling layer is arranged on the side of the microlens array away from the light-transmitting substrate, and the surface of the side of the filling layer facing outward is flat.
[0062] Referring to Figure 4 , the light modulating element 100 includes a light-transmitting substrate 110, a surface of one side of the light-transmitting substrate is a light-incident surface, a surface of the other side of the light-transmitting substrate is provided with a microlens array 120, a filling layer 130 is arranged on the side of the microlens array 120 away from the light-transmitting substrate, and the surface of the side of the filling layer 130 facing outward is flat.
[0063] In the present application, the light-transmitting substrate and the microlens array can be integrally formed, or can be two independent elements.
[0064] In an embodiment, the refractive index of the microlens array is greater than the refractive index of the filling layer. Preferably, the greater the difference between the refractive index of the microlens array and the refractive index of the filling layer, the better.
[0065] In an embodiment, the refractive index of the light-transmitting substrate is greater than the refractive index of the filling layer and less than the refractive index of the microlens array.
[0066] In a specific embodiment, the refractive index of the light-transmitting substrate ranges from 1.5, the refractive index of the microlens array ranges from 1.5 to 1.75, and the refractive index of the filling layer ranges from 1.35 to 1.5.
[0067] It should be noted that, when the light modulating element further includes a filling layer covering the surface of the microlens array, the initial incident angle θ1 and the intermediate incident angle θ5 also satisfy the following formula:
[0068] θ1 = arcsin ((n3 / n1) * sin (α-θ5))
[0069] and when θ1< θ T , θ5≥ θ C , θ C = arcsin(n4 / n3);
[0070] wherein n1 is the refractive index of the external medium of the light modulating element, n3 is the refractive index of the microlens array, n4 is the refractive index of the external medium of the microlens, and α is the angle between the tangent of the position of the light beam incident to the microlens structure surface and the non-structure surface of the microlens, θ T is the target angle, and θ C is the critical angle of total reflection.
[0071] Further, when the surface of the microlens array includes a filling layer, the exit surface of the light beam changes, and the detection incident angle of the light beam incident to the detection plane also changes. At this time, the initial incident angle θ1 and the detection incident angle θ9 satisfy the following formula:
[0072]
[0073] and when θ1< θ T , θ9> θ D ;
[0074] wherein n1 is the refractive index of the external medium of the light modulating element, n3 is the refractive index of the microlens array, n4 is the refractive index of the filling layer, n5 is the refractive index of the external medium of the filling layer, and α is the angle between the tangent of the position of the light beam incident to the structure surface and the non-structure surface of the microlens, θ T is the target angle, and θ D is the optimal detection angle.
[0075] Referring to Figure 5 , the light beam is incident to the light entrance surface (one side surface of the light-transmitting substrate) of the light modulating element from the external medium (with a refractive index of n1) at an incident angle of θ1, is refracted and enters the light-transmitting substrate 110 (with a refractive index of n2) at a refractive angle of θ2. The light beam continues to transmit in the light-transmitting substrate 110 to the other side surface at an incident angle of θ3, is refracted and enters the microlens array 120 (with a refractive index of n3) at a refractive angle of θ4. The light beam continues to transmit in the microlens array 120 to the structure surface at an incident angle of θ5, is refracted and enters the filling layer (with a refractive index of n4) at a refractive angle of θ6. The light beam continues to transmit in the filling layer to the exit surface at an incident angle of θ7, is refracted and enters the external medium (with a refractive index of n5) at a refractive angle of θ8. After entering the external medium, the light beam is incident to the detection plane at an incident angle of θ9.
[0076] Moreover, in the embodiment, the external side surface of the filling layer is the light exit surface, and the filling layer can also protect the microstructure surface of the microlens array from being damaged.
[0077] It should be understood that the transmission path of the light beam is related to the refractive index, and therefore the refractive index of each component in the light modulation element also has certain constraints. Moreover, the refractive index of the microlens array and the parameters of the microlens array surface shape can be optimized in coordination to change the incident angle corresponding to the peak of the outgoing energy, so that the light beam can achieve the maximum outgoing energy when it is incident at the expected incident angle.
[0078] Exemplarily, in a specific embodiment, the light modulation element includes a light-transmitting substrate, a microlens array, and a filling layer. Wherein the refractive index of the light-transmitting substrate is 1.5, the thickness of the light-transmitting substrate ranges from 0.2 mm to 0.5 mm; the refractive index of the microlens array ranges from 1.5 to 1.75, the ratio of the height H and the width W of the microlens ranges from 0.5 to 1; the refractive index of the filling layer is 1.35, and the thickness of the filling layer ranges from 10 μm to 50 μm, which can achieve the peak of the outgoing energy when the light is incident to the light-incoming surface of the light modulation element at 30°.
[0079] Exemplarily, in another specific embodiment, the light modulation element includes a light-transmitting substrate, a microlens array, and a filling layer. Wherein the refractive index of the light-transmitting substrate is 1.5, the refractive index of the microlens array is 1.7, and the refractive index of the filling layer is 1.35, the thickness of the light-transmitting substrate ranges from 0.2 mm to 0.5 mm, the ratio of the height H and the width W of the microlens ranges from 1.25 to 1.5, and the thickness of the filling layer ranges from 10 μm to 50 μm, which can achieve the peak of the outgoing energy when the light is incident to the light-incoming surface of the light modulation element at 40°.
[0080] Implementably, the parameters of each microlens in the microlens array are the same, and the adjacent microlenses can be adjacently arranged or spaced apart. When the spacing between the adjacent microlenses is within a certain range, the size of the peak of the outgoing energy can be reduced by increasing the spacing between the microlenses, and the position of the peak of the outgoing energy is not changed.
[0081] The light modulation element provided by the above embodiments has a light-incoming side and a light-outgoing side arranged oppositely. Since the light-outgoing side has a microstructure and is a microlens array, and the microlenses in the microlens array are designed to have a closed shape with a right-angle side and are rotated 360° around the straight line where the right-angle side is located to form a geometric body, when the light beam is incident to the structural surface of the microlens, the light beam can be modulated by the structural surface of the microlens, so that the light beam can achieve the maximum outgoing energy at the expected incident angle, instead of being fixed at the perpendicular incidence as the peak of the outgoing energy, which makes the application range of the light modulation element wider.
[0082] Further, the initial incident angle corresponding to the highest exit energy of the light beam is set as the target angle, for the light beam with the initial incident angle less than the target angle, the incident angle of the light beam to the micro-lens structure surface is greater than or equal to the total reflection critical angle of the light beam exiting from the structure surface, or the detection incident angle of the light beam to the detection plane is greater than the optimal detection angle, so that the light beam can be totally reflected in the micro-lens array, or be incident to the detection plane with a larger exit angle, thereby the energy peak detected by the detection plane can be shifted, and the target angle can be non-zero.
[0083] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. An optical modulation element having an incident light side and an emergent light side disposed opposite to each other, characterized by, The light beam is incident from the light entrance surface of the light entrance side, and the incident angle is the angle between the incident direction and the normal line of the light entrance surface; the light exit side has a microstructure and is a microlens array, and the microlens in the microlens array is a closed shape with a right angle edge, and the microlens is formed by rotating the right angle edge by 360 degrees around the straight line where the right angle edge is located as the rotation axis, so that when the exit energy of the light beam after the light beam exits from the light exit side is detected on the detection plane, the corresponding incident angle when the exit energy is the highest is not zero; wherein the detection plane is parallel to the light entrance surface.
2. The light modulating element of claim 1, wherein When the light beam is incident from the light entrance surface, the angle between the incident direction and the normal line of the light entrance surface is the initial incident angle; when the light beam is incident to the structure surface of the microlens, the angle between the incident direction and the normal line of the structure surface is the intermediate incident angle; the initial incident angle corresponding to the highest exit energy of the light beam is the target angle; wherein the intermediate incident angle corresponding to the light beam with the initial incident angle smaller than the target angle is greater than or equal to the total reflection critical angle of the light beam exiting from the structure surface, or the detection incident angle of the light beam with the initial incident angle smaller than the target angle incident to the detection plane is greater than the optimal detection angle, so that the target angle is not zero.
3. The light modulating element of claim 2, wherein The initial incident angle θ1 and the intermediate incident angle θ5 satisfy the following formula: θ1=arcsin((n3 / n1)*sin(α-θ5)) and when θ1< θ T , θ5≥ θ C , θ C = arcsin(n4 / n3); wherein n1 is a refractive index of an external medium of the light modulation element, n3 is a refractive index of the microlens array, n4 is a refractive index of an external medium of the microlens, a is an angle of a tangent line at an incident position of the light beam incident to the structure surface and a non-structure surface of the microlens, θ T is the target angle, and θ C is the critical angle of total reflection.
4. The light modulating element of claim 2, wherein The initial incident angle θ1 and the detection incident angle θ7 satisfy the following formula: and when θ1<θ T , θ7>θ D ; wherein n1 is a refractive index of an external medium of the light modulation element, n3 is a refractive index of the microlens array, n4 is a refractive index of an external medium of the microlens, a is an angle of a tangent line at an incident position of the light beam incident to the structure surface and a non-structure surface of the microlens, and θ T is the target angle, and θ D is the optimal detection angle.
5. The light modulating element of claim 4, wherein The optimal detection angle is in the range of 3°-5°.
6. The light modulating element of claim 1, wherein The right angle edge of the closed shape is a straight line, a multi-segment broken line, a curve or a multi-segment curve.
7. The light modulating element of claim 1, wherein The incident angle when the exit energy is the highest is in the range of 0°-55°.
8. The light modulating element of claim 1, wherein The light modulation element comprises a light-transmitting substrate, a surface of the light-transmitting substrate is provided with the microlens array, and the side of the microlens array away from the light-transmitting substrate is provided with a filling layer, and the surface of the side of the filling layer facing outward is flat.
9. The light modulating element of claim 8, wherein The refractive index of the microlens array is greater than the refractive index of the filling layer.
10. The light modulating element of claim 8, wherein The refractive index of the light-transmitting substrate is greater than the refractive index of the filling layer and less than the refractive index of the microlens array.