Diffractive optical module and system
By setting optical elements such as lens phase plates between the diffraction optical element and the focusing lens, the optical path of the zero-order light spot is changed, which solves the problem of the zero-order light spot affecting uniformity, achieves higher uniformity and wider application scenarios, and reduces process requirements.
Patent Information
- Application Number
- CN202510908286.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-09-05
AI Technical Summary
When the delay amount of existing diffractive optical elements does not meet the half-wave condition, the zero-order spot will seriously affect its uniformity, affecting optical applications, and the process requirements are strict.
A zero-order light spot modulation component is set between the diffraction optical element and the focusing lens, including a lens phase plate, a negative lens phase plate, a grating phase plate, etc., to change the optical path of the zero-order light spot and reduce the energy proportion of the zero-order light spot.
Without increasing the difficulty of the process, the proportion of zero-order spot energy is reduced by an order of magnitude, which improves the uniformity and application scenarios of diffraction optical elements and reduces process requirements.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of diffractive optical elements, and in particular to a diffractive optical module and system. Background Art
[0002] Diffractive Optical Elements (DOEs) have broad market application prospects in the fields of photovoltaics, 3C, laser welding, laser marking, medical beauty, and new consumption, and are indispensable optical elements for laser users. For example, liquid crystal diffractive optical elements, by means of light-induced orientation, reasonably modulate the phase of liquid crystal molecules, and can use the birefringence characteristics of liquid crystal to achieve specific input light and output any output light that meets the designed light intensity distribution. That is, after beam shaping and modulation of the Gaussian beam based on the diffractive optical element DOE, a uniformly distributed spot pattern can be output. The pattern can be any circular, linear, square, etc., providing a multi-dimensional solution for the above-mentioned complex and diverse optical scenarios.
[0003] In practice, if the retardation of a diffractive optical element (DOE) does not meet the half-wavelength condition for the wavelength being used, it will result in a severe zero-order spot in the output beam of the diffractive optical element. The presence of this zero-order spot will significantly reduce the uniformity of the diffractive optical element, seriously affecting the optical application of the DOE and causing significant disadvantages in actual optical scene applications. Summary of the Invention
[0004] The object of the present invention is to provide a storage tank monitoring device, system, method and equipment to automatically perform safety monitoring on a monitoring entity.
[0005] To achieve the above object, the present invention provides the following solutions:
[0006] In a first aspect, the present invention provides a diffractive optical module, comprising:
[0007] A diffractive optical element and a zero-order light spot modulation component arranged on a side of the diffractive optical element away from the light source;
[0008] The diffractive optical element is used to modulate the direction and intensity of the incident light emitted by the light source, so that the incident light forms a homogenized surface on the focusing plane after passing through the diffractive optical element and the focusing lens;
[0009] The zero-order light spot adjustment component is used to change the optical path of the zero-order light spot beam, so that the energy proportion of the zero-order light spot on the focusing plane is reduced.
[0010] In some embodiments of the first aspect, the zero-order light spot includes a first zero-order light spot and a comprehensive zero-order light spot, and the zero-order light spot modulation component is a focus adjustment module;
[0011] The focus adjustment module is used to change the focus position of the first zero-order light spot so that the energy proportion of the zero-order light spot on the focusing plane is reduced.
[0012] In some embodiments of the first aspect, the focus adjustment module includes a first focus adjustment unit;
[0013] The first focal length unit is used to adjust the focusing position of the first zero-order light spot in the optical axis direction of the incident light, so that the first zero-order light spot is away from the focusing plane in the optical axis direction.
[0014] In some embodiments of the first aspect, the focus adjustment module further includes a second focus adjustment unit;
[0015] The second focal length adjustment unit is used to cooperate with the first focal length adjustment unit to adjust the focusing position of the first zero-order light spot in the direction perpendicular to the optical axis of the incident light, so that the first zero-order light spot is away from the focusing plane in the direction perpendicular to the optical axis and in the direction of the optical axis.
[0016] In some embodiments of the first aspect, the first focal length adjustment unit includes a lens phase plate and a negative lens phase plate sequentially stacked on the diffraction element.
[0017] In some embodiments of the first aspect, the second focal length adjustment unit includes a grating phase plate and a negative grating phase plate, the grating phase plate is arranged on the side of the lens phase plate away from the light source, and the negative grating phase plate is arranged on the side of the negative lens close to the focusing lens.
[0018] In some implementations of the first aspect, the zero-order spot modulation module is a filtering module.
[0019] The filtering module is used to filter out the zero-order light spot of the incident light after passing through the diffractive optical element, so that the zero-order light spot on the focusing plane is reduced.
[0020] In some embodiments of the first aspect, the filtering module includes a grating phase plate and a 4f optical component, the grating phase plate is arranged on a side of the lens phase plate away from the light source, and the 4f optical component is arranged between the grating phase plate and the focusing lens.
[0021] In a second aspect, the present application provides a diffraction optical system, which includes the diffraction optical module and a focusing lens as described in the first aspect.
[0022] According to the specific embodiments provided in this application, the following technical effects are disclosed:
[0023] The present application provides a diffraction optical module and system, which suppresses the intensity of the zero-order light spot of the diffraction optical element by arranging a zero-order light spot modulation component between the diffraction optical element and the focusing lens, changing the optical path of the zero-order light spot, and reducing the zero-order light spot energy ratio on the focusing plane. That is, an optical element is superimposed on the basic phase-type diffraction optical element to achieve the weakening of the zero-order light spot energy, and ultimately, under the same process level conditions, the comprehensive zero-order energy ratio is reduced by one order of magnitude compared with the traditional optical module, and there is no need to strictly control the half-wave delay amount during the preparation process of the diffraction optical element, so as to eliminate the adverse effects of the zero-order light modulation on the diffraction optical element, thereby reducing the process requirements of the diffraction optical element. And ensure the final diffraction result of the light source, greatly improve the uniformity of the diffraction result of the diffraction optical element, and broaden the application scenarios of the diffraction optical element. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0025] Figure 1 Schematic diagram of the structure of a diffraction optical module in the related art;
[0026] Figure 2 A schematic diagram of simulation results of light intensity distribution of diffraction results of a diffraction optical module in the related art;
[0027] Figure 3 Schematic diagram of test results of light intensity distribution of diffraction results of a diffraction optical module in the related art;
[0028] Figure 4 Schematic diagram of the structure of the diffraction optical system of some embodiments of the present application;
[0029] Figure 5 Schematic diagram of simulation results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 0 in some embodiments of the present application;
[0030] Figure 6 Schematic diagram of the test results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 0 in some embodiments of the present application;
[0031] Figure 7 Schematic diagram of simulation results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 10 μm in some embodiments of the present application;
[0032] Figure 8Schematic diagram of test results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 10 μm in some embodiments of the present application;
[0033] Figure 9 Schematic diagrams of the structures of diffraction optical systems according to some other embodiments of the present application;
[0034] Figure 10 Schematic diagram of simulation results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 15 μm in some embodiments of the present application;
[0035] Figure 11 Schematic diagram of test results of light intensity distribution when the optical delay difference is 15 nm and the lens phase deviation is 15 μm in some embodiments of the present application;
[0036] Figure 12 Schematic diagram of the structure of the diffraction optical system of some further embodiments of the present application. DETAILED DESCRIPTION
[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0039] It can be understood that diffractive optical elements (DOEs) are optical elements that use the principle of light diffraction to control the propagation direction and intensity distribution of light. They are usually formed by forming periodic or non-periodic microstructures on a substrate material through photolithography, nanoimprinting or electron beam technology. In practice, when the incident light wave encounters a microstructured surface with a periodic or non-periodic structure, diffraction will occur. In addition, light modulation is achieved by precisely designing the surface structure of the microstructure.
[0040] For example, by etching or embossing specific microstructures (such as microlens arrays, gratings, etc.) on the surface of transparent materials (such as glass or plastic), the phase, amplitude or polarization state of light can be changed, thereby achieving functions such as light beam shaping, splitting, and focusing.
[0041] like Figure 1 The figure shows a schematic diagram of the working principle structure of a diffractive optical element in related technology.
[0042] like Figure 1 As shown, the diffractive optical element is a 1257 μm element made of liquid crystal polymer (LCP) material, which is arranged on a lens substrate to form a diffractive optical element.
[0043] like Figure 2 Shown Figure 1 The diagram shows the light intensity distribution of the diffractive optical element in the related art, that is, a diagram showing the simulation results of the light intensity distribution when the optical delay difference is 15 nm.
[0044] like Figure 3 Shown Figure 1 The experimental data of the diffractive optical element of the related art is shown, that is, the data diagram of the actual test when the optical delay difference is 15nm.
[0045] Combine Figure 2 and Figure 3 As shown, the zero-order and homogenizing surfaces of the diffractive optical element in the related art are at the same focal length, resulting in a serious zero-order spot in the output light beam.
[0046] Moreover, the greater the actual delay of the diffractive optical element deviates from the half-wave condition, the greater the proportion of the power density of the zero-order spot in the output light, which often leads to a significant decrease in the uniformity of the diffractive optical element, seriously affecting the optical application of DOE.
[0047] Therefore, the optical module requires strict control of the half-wave delay during the preparation of the diffractive optical element to effectively eliminate the adverse effects of the zero-order light modulation on the diffractive optical element, which places more stringent requirements on the process of preparation.
[0048] In the present application, in order to effectively suppress the excessive intensity of the zero-order spot formed on the homogenizing surface during the actual use of the diffractive optical element on the basis of low process requirements, and ultimately ensure the uniformity and optical application of the diffractive optical element, an optical path modulation module, i.e., a zero-order spot adjustment component, is set between the diffractive optical element and the focusing lens. In the process where the incident light passes through the diffractive optical element and the focusing lens and finally presents a homogenizing surface on the focusing surface, the optical path of the zero-order spot beam is changed, thereby ultimately suppressing the intensity of the zero-order spot of the diffractive optical element and reducing the light intensity of the zero-order spot on the homogenizing surface. There is no need to strictly control the precise control of the half-wave delay amount during the preparation of the LCP diffractive optical element.
[0049] This approach combines a phase-type diffractive optical element (DOE) with a zero-order spot adjustment assembly composed of various optical elements. While reducing the intensity of the zero-order spot, it ensures that the diffraction results of the DFO remain unchanged, and the position of the diffraction results remains unchanged. Furthermore, without increasing the complexity of the process, the overall zero-order energy ratio is reduced by an order of magnitude compared to traditional optical modules under the same process level. This is crucial for the process iteration of liquid crystal micro-nano production lines.
[0050] In order to better understand the diffraction optical module provided by this application, it is described in detail below with reference to the accompanying drawings.
[0051] The laser light source in the embodiment of the present application can be a 1080nm laser with a laser power of 50mw, a wavelength range of 1080nm±1m, a beam quality M2<1.1, and a roundness greater than 95%. The diffractive optical element can be a liquid crystal polymer diffractive optical element. This application does not impose any restrictions on this.
[0052] Figure 4 The following is a schematic diagram of the structure of the diffraction optical module of some embodiments of the present application. Figure 4 As shown, the module includes:
[0053] A diffractive optical element and a zero-order light spot modulation component arranged on a side of the diffractive optical element away from a light source.
[0054] The diffractive optical element is used to modulate the direction and intensity of the incident light emitted by the light source, so that the incident light forms a homogenized surface on the focusing surface after passing through the diffractive optical element and the focusing lens.
[0055] The zero-order light spot adjustment component is used to change the optical path of the zero-order light spot beam, so that the energy proportion of the zero-order light spot on the homogenization surface is reduced.
[0056] Specifically, in the embodiment of the present application, Figure 1 On the basis of the diffraction optical structure of the related technology shown, a group of optical elements (zero-order spot adjustment components) are arranged between the diffraction optical element and the focusing lens to modulate the light beam of the incident light passing through the diffraction element, so as to change the optical path of the zero-order spot light beam formed therein, so that the energy proportion of the zero-order spot on the homogenized surface at the focusing position is reduced, thereby reducing the light intensity of the zero-order spot on the focusing surface and ensuring the diffraction result of the incident light.
[0057] It can be understood that the diffraction optical module of the embodiment of the present application suppresses the intensity of the zero-order spot of the diffraction optical element by setting a zero-order spot modulation component between the diffraction optical element and the focusing lens, changing the optical path of the zero-order spot, and reducing the zero-order spot on the focusing plane. That is, an optical element is superimposed on the basic phase-type diffraction optical element to achieve the weakening of the zero-order spot energy, ultimately reducing the comprehensive zero-order energy ratio by an order of magnitude compared to the traditional optical module under the same process level conditions. There is no need to accurately control the half-wave delay amount during the preparation of the LCP diffraction optical element, which can eliminate the adverse effects of the zero-order on the light modulation of the diffraction optical element, reducing the process requirements of the diffraction optical element. It also ensures the final diffraction result of the light source, greatly improves the uniformity of the diffraction result of the diffraction optical element, and broadens the application scenarios of the diffraction optical element.
[0058] It can be understood that in the embodiment of the present application, since other optical elements are added to the optical structure, when the incident light passes through the diffraction element and the focusing lens, the final zero-order light spot on the focusing plane may include the first zero-order light spot and the integrated zero-order light spot.
[0059] The first zero-order spot refers to the main maximum of the zero-order diffraction spot in the output light of the diffractive optical element, that is, the central spot where no diffraction occurs. It is the brightest part of the diffraction pattern and is usually located at the center of the optical axis.
[0060] The comprehensive zero-order spot refers to the result of comprehensive consideration of multiple factors other than the first zero-order spot. It is not only related to the grating's diffraction efficiency and the spot's light intensity distribution, but is also influenced by system design and optimization. In some embodiments of the present application, the zero-order spot adjustment component can be a focal length adjustment module to change the focal position of the first zero-order spot, thereby reducing the proportion of zero-order spot energy on the focal plane.
[0061] That is, in this embodiment, the focusing position of the first zero-order light spot is adjusted by the zero-order light spot adjustment component so that the focusing position of the first zero-order light spot leaves the focusing plane, thereby ensuring that the energy proportion of the zero-order light spot on the homogenization plane is reduced, thereby achieving the weakening of the light intensity of the zero-order light spot in the homogenization plane.
[0062] Optionally, in some embodiments of the present application, the focus adjustment module may include a first focus adjustment unit, which is used to adjust the focusing position of the first zero-order light spot in the optical axis direction of the incident light, so that the first zero-order light spot is away from the focusing plane in the optical axis direction.
[0063] Specifically, in this embodiment, the first focal length adjustment unit is provided as a zero-order light spot adjustment component to adjust the focus position of the first zero-order light spot in the optical axis direction so that the final focus is away from the focus plane.
[0064] For example, Figure 4 As shown, in some embodiments, the first focal length adjustment unit includes a lens phase plate and a negative lens phase plate sequentially stacked on the diffraction element.
[0065] That is, in this optical structure, the diffraction optical element in the related art is improved, and the improved structure can include an optical homogenization module of liquid crystal polymer diffraction optical element + lens phase plate + negative lens phase plate, that is, a lens and a negative lens phase plate are superimposed on the basis of the ordinary phase-type diffraction optical module in the related art.
[0066] In practice, when the incident light passes through the positive and negative lenses on one side of the diffraction element, the positive and negative lenses cancel each other out, thereby keeping the homogenized position on the focal plane and defocusing the first zero-order light spot. With the same delay error accuracy, the overall zero-order light spot energy ratio will be reduced by an order of magnitude.
[0067] That is Figure 4 As shown, in this structure, the first zero-order light spot is defocused so that its focal position leaves the homogenizing surface and is on the optical axis before and after the homogenizing surface, leaving only the integrated zero-order light spot on the homogenizing surface, which ultimately greatly reduces the light energy of the zero-order light spot on the homogenizing surface.
[0068] For example, Figure 5 and Figure 6 As shown, for use Figure 4 The structure shown, when the optical delay difference is 15nm, the theoretical simulation data and actual test results when the lens phase deviation is 0. Figure 5 and Figure 6 It can be seen that the simulation value reduces the zero-order spot energy ratio by one order of magnitude compared with the structure in the related art.
[0069] Figure 7 and Figure 8 The figure shows the light intensity distribution diagram of the theoretical simulation test data and the actual test results when the optical delay difference is 15nm and the lens phase deviation is 10μm. Figure 7 and Figure 8 It can be seen that compared with the related technology, the zero-order spot energy of the improved optical structure is still one order of magnitude lower than the zero-order spot energy in the related technology in the scenario where the phase deviation increases.
[0070] It is understandable that Figure 4 As shown in FIG. 1 , when the lens phase plate bonding error precision deviates, the prepared liquid crystal polymer homogenized DOE sample is prone to annular wavy stripes.
[0071] Furthermore, in order to improve the optical performance of the diffraction optical module of the above embodiment and solve the problem that when the lens phase plate bonding error accuracy deviates in the optical structure of the above embodiment, the prepared liquid crystal polymer homogenized DOE sample is prone to annular wavy stripes, the diffraction optical module of the above embodiment is further improved.
[0072] That is, in some embodiments of the present application, the focus adjustment module also includes a second focus adjustment unit, which is used to cooperate with the first focus adjustment unit to adjust the focusing position of the first zero-order light spot in the direction of the optical axis perpendicular to the incident light, so that the first zero-order light spot is away from the focusing plane in the direction perpendicular to the optical axis and in the direction of the optical axis.
[0073] That is, in this embodiment, based on the adjustment of the first zero-order light spot in the direction of the optical axis, further adjustment is made in the direction perpendicular to the optical axis.
[0074] Correspondingly, if Figure 9 As shown, in some embodiments of the present application, correspondingly, in this structure, the second focal length adjustment unit includes a grating phase plate and a negative grating phase plate, the grating phase plate is arranged on the side of the lens phase plate away from the light source, and the negative grating phase plate is arranged on the side of the negative lens close to the focusing lens.
[0075] For example, Figure 9 As shown in the figure, in order to solve the pain point of annular wavy stripes, through theoretical simulation, the underlying optical design found that the annular wavy stripes in the homogenized intensity mainly come from the interference between the defocused zero order and the homogenized light intensity on the homogenizing surface when the DOE phase is misaligned with the negative lens phase plate.
[0076] In some embodiments of the present application, the positive and negative grating phases can be further superimposed on the two phase plates, that is, a second focal length adjustment unit can be added to defocus the zero order away from the optical axis of the uniform intensity, thereby successfully eliminating the annular intensity wave stripes caused by misalignment and delay errors.
[0077] In this structure, the negative lens in the optical path system is used to form an optical module with the negative grating phase plate, which is located after the homogenizing phase plate that superimposes the positive grating phase and the lens phase. This optical module is used to shift the homogenized light spot back to the focal plane. In addition, the positive and negative grating phases are further superimposed on the two phase plates, which defocuses the zero order away from the optical axis of the homogenized intensity, eliminating the annular intensity wave stripes caused by misalignment and delay errors. In other words, the positive grating phase plate and the lens in the optical path system form an optical module, which is located after the diffractive optical element and is used to achieve the offset of the homogenized position based on the incident light of different polarization states.
[0078] In practice, when this structure modulates the incident light, the positive grating phase plate and the positive lens phase homogenizing phase plate, when the laser passes through this phase plate, the zero-order light is not modulated and is located on the focal plane optical axis after being focused by the lens. The homogenized light spot is affected by the grating phase and the lens phase. Due to the different modulation of left-handed circularly polarized light and right-handed circularly polarized light, it is separated into two parts of homogenization: upward off-axis with the homogenization position moved forward and downward off-axis with the homogenization position moved backward. In subsequent modulation, the relative position of the zero-order and homogenized light spots remains unchanged.
[0079] The negative lens phase plate superimposed with the negative grating shifts the two separated homogenized light spots back to the focal plane. Since the relative position of the zero-order light spot and the homogenized light spot remains unchanged, the zero-order light spot is moved to an upper off-axis position with forward focus and a lower off-axis position with backward focus, respectively. In other words, the first positive grating lens superimposed with the phase plate completely separates the homogenized light spots. The second negative grating lens superimposed with the phase plate returns the homogenized light spot to the focal plane, while the original first zero-order light spot moves from the focal plane to an oppositely defocused and oppositely shifted position. Aside from the integrated zero-order light spot retained by the second zero-order light, the zero-order light spot has essentially no effect on the diffraction results, and the diffraction results remain unchanged.
[0080] like Figure 4 As shown, the comprehensive zero-order energy ratio = the first zero-order light spot energy ratio * the second zero-order energy ratio (under the same process preparation conditions, the zero-order energy ratio of this solution is reduced by one order of magnitude).
[0081] Among them, Figure 4 As shown, the first zero-order light spot is the first zero-order light spot close to the focusing lens, and the second zero-order light spot is the first zero-order light spot far away from the focusing lens.
[0082] For example, Figure 10 and Figure 11 As shown in the figure, when the optical delay difference is 15nm, the lens phase deviation is 15μm. Figure 10 and Figure 11 It can be seen that it is similar to the result diagram in the related art and Figure 4 Compared with the result schematic diagram of the structure shown in FIG, there is almost no zero-order light spot in the test results of this structure.
[0083] It can be understood that by arranging positive and negative lenses and positive and negative grating phase plates between the diffractive optical element and the focusing lens, that is, the positive grating phase plate and the lens phase plate constitute a set of optical modules, and the negative lens and the negative grating phase plate constitute a set of optical modules, and are located after the diffractive optical element on which the positive grating phase and the lens phase are superimposed, they are used to reverse the uniformed light spot back to the focal plane. In addition, the positive and negative grating phases are further superimposed on the two phase plates, which defocuses the zero order away from the optical axis of the uniformed intensity, eliminating the annular intensity wave stripes caused by misalignment and delay errors, greatly improving the uniformity of the diffraction results of the diffractive optical element, broadening the application scenarios of the diffractive optical element, and reducing the process complexity of the diffraction optical system.
[0084] Optionally, the positive and negative lens phase plates and the positive and negative grating phase plates involved in the above embodiments of the present application can be of the same size.
[0085] Typically, the optical lens size can be 25.4mm in diameter and 1.6mm in thickness.
[0086] Furthermore, when forming the above structures, the two phase plates can be used in close contact, and the distance between the phase plate and the lens is not limited, and usually does not exceed 500 mm.
[0087] Optionally, in some embodiments of the present application, an optical structure is further provided to achieve filtering of the zero-order light spot.
[0088] That is, in some embodiments, the zero-order spot adjustment component can also be a filtering module, and the filtering module is used to filter the zero-order spot of the incident light after passing through the diffraction optical element, so that the energy proportion of the zero-order spot on the focusing plane is reduced.
[0089] Specifically, if Figure 12 As shown, the filtering module may include a grating phase plate and a 4f optical component. The grating phase plate is arranged on a side of the lens phase plate away from the light source, and the 4f optical component is arranged between the grating phase plate and the focusing lens.
[0090] Among them, Figure 12 As shown, the 4f optical component can be composed of two c The lens consists of an input surface (where the homogenized phase + grating phase plate is placed), a spectrum surface (where the small hole is placed), and an output surface with a spacing of f c distance.
[0091] In practice, in this optical system, a pinhole filter is placed on the spectrum plane of the 4f optical component (the focal plane between the two lenses). The size of the pinhole is designed to allow only non-zero-order diffraction light to pass through. The zero-order light spot will be blocked by the pinhole because its energy is concentrated in the center. After the subsequent Fourier transform through the second lens, the output light field will filter out the zero-order light spot, thereby improving the light field quality.
[0092] It can be understood that the optical structure in this embodiment only needs to filter out the zero order, so there is no strict positioning accuracy requirement, which reduces the operating requirements, thereby broadening the use scenarios and usage complexity of the optical structure.
[0093] In addition, in this embodiment, the zoom ratio of 4f can be changed by changing the light, thereby scaling the size of the final homogenized light spot.
[0094] On the other hand, in some embodiments of the present application, a diffraction optical system is further provided, which includes the diffraction optical module of each of the above embodiments and a focusing lens.
[0095] In practice, after the incident light from the light source passes through the diffractive optical element, it passes through the zero-order spot adjustment component in the optical system, which further modulates the optical path. Ultimately, the zero-order spot on the focused homogenization plane is eliminated or reduced, thereby eliminating the adverse effects of the zero-order light modulation on the diffractive optical element, reducing the process requirements of the diffractive optical element. It also ensures the final diffraction result of the light source, greatly improving the uniformity of the diffraction optical element's diffraction results, and broadening the application scenarios of diffractive optical elements.
[0096] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0097] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.
Claims
1. A diffraction optical module, characterized in that: The diffraction optical module includes: A diffractive optical element and a zero-order light spot modulation component arranged on a side of the diffractive optical element away from the light source; The diffractive optical element is used to modulate the direction and intensity of the incident light emitted by the light source, so that the incident light forms a homogenized surface on the focusing plane after passing through the diffractive optical element and the focusing lens; The zero-order light spot adjustment component is used to change the optical path of the zero-order light spot beam, so that the proportion of zero-order energy on the homogenization surface is reduced.
2. The diffraction optical module according to claim 1, wherein: The zero-order light spot includes a first zero-order light spot and a comprehensive zero-order light spot, and the zero-order light spot modulation component is a focus adjustment module; The focal length adjustment module is used to change the focus position of the first zero-order light spot so that the energy proportion of the zero-order light spot on the homogenization surface is reduced.
3. The diffraction optical module according to claim 2, wherein: The focus adjustment module includes a first focus adjustment unit; The first focal length unit is used to adjust the focusing position of the first zero-order light spot in the optical axis direction of the incident light, so that the first zero-order light spot is away from the homogenization surface in the optical axis direction.
4. The diffraction optical module according to claim 3, wherein: The focus adjustment module further includes a second focus adjustment unit; The second focal length adjustment unit is used to cooperate with the first focal length adjustment unit to adjust the focusing position of the first zero-order light spot in the direction perpendicular to the optical axis of the incident light, so that the first zero-order light spot is away from the homogenization surface in the direction perpendicular to the optical axis and in the direction of the optical axis.
5. The diffraction optical module according to claim 3, wherein: The first focal length adjustment unit includes a lens phase plate and a negative lens phase plate stacked in sequence on the diffraction element.
6. The diffractive optical module according to claim 4, wherein: The second focal length adjustment unit includes a grating phase plate and a negative grating phase plate. The grating phase plate is arranged on a side of the lens phase plate away from the light source, and the negative grating phase plate is arranged on a side of the negative lens close to the focusing lens.
7. The diffractive optical module according to claim 1, wherein: The zero-order light spot modulation module is a filtering module. The filtering module is used to filter out the zero-order light spot of the incident light after passing through the diffractive optical element, so that the energy proportion of the zero-order light spot on the focusing plane is reduced.
8. The diffractive optical module according to claim 7, wherein: The filtering module includes a grating phase plate and a 4f optical component. The grating phase plate is arranged on a side of the lens phase plate away from the light source, and the 4f optical component is arranged between the grating phase plate and the focusing lens.
9. A diffraction optical system, characterized in that: The diffraction optical system includes the diffraction optical module and focusing lens as described in any one of items 1-7.