Preparation system and method of achromatic panchromatic holographic optical element
Through the one-time exposure molding method, the multi-glue lens and 4f system beam-expanding method are used to simplify the preparation process of achromatic holographic optical components, and achieve focal overlap in the long wavelength range, which is suitable for AR display.
Patent Information
- Application Number
- CN202510688153.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-08-08
AI Technical Summary
The process of preparing achromatic holographic optical components in the prior art is complex and requires three exposures to reduce the chromatic aberration.
The laser emission component is used to simultaneously emit red, green and blue linearly polarized light, and the beam is expanded by a multi-glue lens and a 4f system to adjust the polarization direction and power density, so that the reference light and signal light overlap on the holographic optical element, and the achromatic ability of the multi-glue lens achieves the overlap in focus.
The preparation process is simplified, the focus overlap in the long wavelength range is achieved, the preparation efficiency is improved, and it is suitable for AR display.
Smart Images
Figure CN120447311A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of holographic optics, and more specifically, relates to a system and method for preparing an achromatic full-color holographic optical element. Background Art
[0002] Holographic optical elements are advanced optical devices based on holographic technology. By recording and reproducing the phase and amplitude information of light waves, they can achieve complex wavefront modulation and are widely used in optical communications, microscopic imaging, virtual reality and other fields.
[0003] The preparation of achromatic holographic optical elements can effectively correct chromatic aberration, improve the quality of multi-wavelength imaging, expand its application range in optical communications, microscopic imaging, virtual reality and other fields, meet the requirements of modern optical systems for high performance and high precision, and promote the further development of optical technology.
[0004] However, the traditional method of preparing achromatic holographic optical elements is to use the same optical path to expose different holograms with different laser wavelengths, and then superimpose these holograms to achieve the same modulation of different wavelengths. This method requires three exposures to reduce chromatic aberration, which is more complicated in terms of process.
[0005] Therefore, how to simplify the preparation process of achromatic holographic optical elements is an urgent problem to be solved. Summary of the Invention
[0006] In view of the defects of the prior art, the purpose of the present application is to provide a system and method for preparing an achromatic full-color holographic optical element, which adopts a one-time exposure molding process and has a simpler process.
[0007] To achieve the above objectives, in a first aspect, the present application provides a system for preparing an achromatic, full-color holographic optical element, comprising: Laser emission assembly, used for simultaneously emitting red, green and blue linearly polarized light; Beam expansion component, used to expand the red, green and blue linear polarized light into the same size; A beam combining and splitting component is used to combine the expanded red, green and blue linearly polarized light into white light, and to split the white light into reference light and signal light; A polarization adjustment component is used to adjust the polarization direction of the reference light so that the polarization of the reference light and the signal light are consistent; A power density adjustment component is used to adjust the polarization directions of the three-color linear polarized light respectively so that the power densities of the blue light, green light and red light components in the reference light and the signal light are equal; The reflective assembly includes a multi-cemented lens, which is used to reflect the signal light and then irradiate it onto the holographic optical element through the multi-cemented lens, and also reflect the reference light and irradiate it onto the holographic optical element, wherein the signal light and the reference light are irradiated onto the same position of the holographic optical element; wherein the exposure dose required for the holographic optical element is set by controlling the opening time of the red, green and blue linear polarized light.
[0008] The beneficial effects of the present application are as follows: the present application adopts the method of recording multiple glued lenses to eliminate chromatic aberration. The multiple glued lenses have a certain achromatic aberration capability and can achieve focus coincidence in a long wavelength range. The double-beam exposure method is used to prepare the achromatic holographic optical element. The three laser beams are expanded separately through three 4f systems and then combined. One beam is then irradiated onto the holographic optical element through the multiple glued lenses to interfere with the other beam of parallel light. This method is formed by one-time exposure, which is simpler in process, and can realize achromatic AR display in conjunction with the spatial light modulator.
[0009] As a further preference, the multi-cemented lens is a doublet lens or a triplet lens.
[0010] As a further preferred embodiment, the exposure dose required for the holographic optical element is Q The calculation formula is:
[0011] Where, P Indicates the power density of signal light or reference light; t Indicates the turn-on time of red, green and blue linear polarized light.
[0012] As a further preference, the laser emitting assembly includes three single longitudinal mode lasers, red, green and blue, and the beam expanding assembly includes three 4f systems.
[0013] As a further preferred embodiment, the beam combining and splitting components include: A first reflector is used to reflect any one of the expanded red, green and blue linearly polarized laser beams to a first dichroic mirror; a first dichroic mirror, configured to reflect one of the remaining two laser beams to a second dichroic mirror, and transmit the laser beam reflected by the first reflector to the second dichroic mirror; a second dichroic mirror, configured to reflect the other of the remaining two laser beams and combine the laser beams reflected and transmitted by the first dichroic mirror into white light; A polarization beam splitter is used to split the white light into reference light and signal light.
[0014] As a further preferred embodiment, the polarization adjustment component includes a first half-wave plate, and the polarizations of the reference light and the signal light are made consistent by rotating the first half-wave plate to a 90° direction; The power density adjustment component includes three second half-wave plates, and the directions of the three second half-wave plates are rotated to make the power densities of the blue light, green light and red light components in the reference light and the signal light equal.
[0015] As further preferred, the reflective component includes: The second reflecting mirror is used to reflect the signal light and then irradiate the signal light onto the holographic optical element through the multi-cemented lens; The third reflecting mirror is used to reflect the reference light and irradiate it onto the holographic optical element. The signal light and the reference light are irradiated onto the same position of the holographic optical element.
[0016] In a second aspect, the present application provides a method for preparing an achromatic full-color holographic optical element, comprising the following steps: Emit red, green and blue linearly polarized light; Expand the red, green and blue linear polarized light into the same size; Combining the expanded red, green, and blue linearly polarized light into white light, and splitting the white light into reference light and signal light; Adjust the polarization direction of the reference light so that the polarization of the reference light and the signal light are consistent; Adjust the polarization directions of the three-color linear polarized light respectively so that the power density of the blue light, green light and red light components in the reference light and the signal light are equal; The signal light is reflected and then irradiated onto the holographic optical element through a multi-crystallized lens, and the reference light is also reflected and irradiated onto the holographic optical element. The signal light and the reference light are irradiated onto the same position on the holographic optical element. The exposure dose required for the holographic optical element is set by controlling the opening time of the red, green and blue linear polarized lights.
[0017] In a third aspect, the present application provides a holographic optical element, which is prepared using the above-mentioned method for preparing an achromatic and full-color holographic optical element.
[0018] In a fourth aspect, the present application provides an application of the holographic optical element described above, which is applied in AR display.
[0019] It can be understood that the beneficial effects of the second, third and fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 1 is a structural diagram of a system for preparing an achromatic and full-color holographic optical element provided in an embodiment of the present application; Figure 2 It is a structural diagram of the AR display system provided in an embodiment of the present application. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0022] It should be understood that, in the description of this application, the term "plurality" means two or more, unless otherwise clearly and specifically defined; the terms "first" and "second" etc. are used to distinguish different objects, rather than to describe a specific order of objects.
[0023] In order to simplify the preparation process of achromatic holographic optical elements, the present application provides a preparation system for achromatic full-color holographic optical elements, which includes a laser emission component, a beam expansion component, a beam combining and splitting component, a polarization adjustment component, a power density adjustment component and a reflection component.
[0024] The laser emitting assembly is configured to simultaneously emit red, green, and blue linearly polarized light. Specifically, the laser emitting assembly provided in this embodiment may include three single-longitudinal-mode lasers: red, green, and blue. The blue single-longitudinal-mode laser 11 emits a laser with a wavelength of 439 nm, the green single-longitudinal-mode laser 12 emits a laser with a wavelength of 532 nm, and the red single-longitudinal-mode laser 13 emits a laser with a wavelength of 650 nm.
[0025] The beam expansion assembly is used to expand the red, green and blue linearly polarized lights into the same size. Specifically, the beam expansion assembly provided in this embodiment may include three 4f systems 21 composed of two lenses.
[0026] The beam combining and splitting components are used to combine the expanded red, green and blue linearly polarized light into white light, and split the white light into reference light and signal light.
[0027] In this embodiment, the beam combining and splitting assembly may include a reflector 31 , a dichroic mirror 32 , a dichroic mirror 33 and a polarization beam splitter 34 .
[0028] The reflector 31 is used to reflect any one of the expanded red, green, and blue linearly polarized laser beams to the dichroic mirror 32. The dichroic mirror 32 is used to reflect one of the remaining two laser beams to the dichroic mirror 33 and transmit the laser beam reflected by the reflector 31 to the dichroic mirror 33. The dichroic mirror 33 is used to reflect the other of the remaining two laser beams and combine the laser beams reflected and transmitted by the dichroic mirror 32 into white light. The polarization beam splitter 34 is used to split the white light into reference light and signal light.
[0029] The polarization adjustment component is used to adjust the polarization direction of the reference light so that the reference light and the signal light have the same polarization. Specifically, the polarization adjustment component provided in this embodiment may include a half-wave plate 41, which is rotated to 90 degrees to make the reference light and the signal light have the same polarization.
[0030] The power density adjustment assembly is used to adjust the polarization directions of the three linearly polarized lights, respectively, to equalize the power densities of the blue, green, and red light components in the reference and signal lights. Specifically, the power density adjustment assembly provided in this embodiment includes three half-wave plates 51-53. By rotating the orientations of the three second half-wave plates, the power densities of the blue, green, and red light components in the reference and signal lights are equalized.
[0031] The reflective assembly includes a multi-crystal lens 63, which reflects the signal light and then irradiates it onto the holographic optical element. It also reflects the reference light and irradiates it onto the same location on the holographic optical element. The exposure dose required for the holographic optical element is set by controlling the on-time of the three linearly polarized red, green, and blue light.
[0032] It should be noted that the multi-cemented lens 63 provided in this embodiment is formed by bonding multiple lenses together through optical gluing, and chromatic aberration is corrected by combining lenses of different materials. Specifically, the multi-cemented lens 63 provided in this embodiment can be a doublet or a triplet.
[0033] In this embodiment, the reflective assembly may further include two reflective mirrors, wherein the reflective mirror 62 is used to reflect the signal light and then irradiate it onto the holographic optical element through the multi-cemented lens 63; the reflective mirror 61 is used to reflect the reference light and then irradiate it onto the same position on the holographic optical element.
[0034] The manufacturing principle of the manufacturing system of the achromatic full-color holographic optical element provided in this embodiment is as follows: The lasers emitted by the three single-longitudinal-mode lasers (red, green, and blue) are expanded into parallel beams of uniform radius through three 4f systems. The 4f system consists of a double lens, which expands the light spots of the three lasers to the same size for subsequent alignment and beam combination. The blue laser is reflected by the reflector 31 and then passes through the dichroic mirror 32 to combine with the reflected green laser to form blue-green light. Similarly, the blue-green light passes through the dichroic mirror 33 to combine with the red light to form white light. The white light is then divided into reference light and signal light by the polarization beam splitter 34. The polarization directions of the two beams of linear polarized light emitted by the single longitudinal mode laser beam are completely perpendicular after passing through the polarization beam splitter 34. The half-wave plate 41 is rotated to 90° to make the polarization of the reference light and the signal light consistent. The half-wave plates 51, 52 and 53 are then rotated to a certain angle to make the power density of the blue light, green light and red light components in the reference light and the signal light equal, ensuring the best interference effect of the two beams. The signal light is reflected by the reflector 62 and then irradiated onto the holographic optical element through the multi-crystal lens 63. The reference light is also irradiated onto the holographic optical element through the reflector 61. The two beams of light are irradiated on the same position on the holographic optical material, so that the wavefront of the multi-crystal lens 63 is recorded on the holographic optical element. The recorded multi-crystal lens can realize the convergence of the three laser wavelengths used to the same point. Then, the required exposure time t is calculated according to the exposure dose Q of the holographic optical element and the power P of the signal light or reference light:
[0035] Among them, Q is the parameter provided by the holographic optical element, and P is measured by a power meter. The recording of the holographic optical material can be completed by setting the opening time of the three lasers to t, so that the polymerization effect occurs completely, allowing the monomers to better aggregate to form a grating, ensuring a high diffraction efficiency of the holographic optical element.
[0036] The preparation system provided in this embodiment is simple and can be formed by one-time exposure, and the process is also simpler. By utilizing the achromatic function of the multi-cemented lens and the independent beam expansion of the three light beams without introducing additional chromatic aberration, the preparation of achromatic holographic optical elements can be achieved.
[0037] The beneficial effects of this embodiment are as follows: this embodiment adopts the method of recording multiple glued lenses to eliminate chromatic aberration. The multiple glued lenses have a certain achromatic aberration capability and can achieve focus coincidence in a long wavelength range. The double-beam exposure method is used to prepare the achromatic holographic optical element. The three laser beams are expanded separately by three 4f systems and then combined. One beam is then irradiated onto the holographic optical element through the multiple glued lenses to interfere with the other beam of parallel light. This method is formed by one-time exposure, which is simpler in process, and can realize achromatic AR display in conjunction with the spatial light modulator.
[0038] Based on the same inventive concept, the present application also provides a method for preparing an achromatic full-color holographic optical element, comprising the following steps: Step 1: Emit red, green and blue linearly polarized light.
[0039] Step 2: Expand the red, green, and blue linearly polarized light beams to the same size.
[0040] Step 3: Combine the expanded red, green, and blue linearly polarized light into white light, and then split the white light into reference light and signal light.
[0041] Step 4: Adjust the polarization direction of the reference light so that the polarization of the reference light and the signal light are consistent.
[0042] Step 5: Adjust the polarization directions of the three-color linear polarized light respectively so that the power density of the blue light, green light, and red light components in the reference light and the signal light are equal; Step 6: The signal light is reflected and then irradiated onto the holographic optical element through the multi-crystal lens. The reference light is also reflected and irradiated onto the holographic optical element. The signal light and reference light are irradiated onto the same position on the holographic optical element. The exposure dose of the holographic optical element is achieved by controlling the on-time of the three linearly polarized lights of red, green, and blue.
[0043] It should be noted that the detailed implementation method of each step provided in this embodiment can be found in the description of the aforementioned system embodiment, and will not be repeated in this embodiment.
[0044] In addition, the present application also provides a holographic optical element prepared by the above-mentioned method for preparing an achromatic full-color holographic optical element.
[0045] The holographic optical element provided in this embodiment can be applied to AR display.
[0046] Figure 2 This is a structural diagram of the AR display system provided by this application. The AR display system provided in this embodiment also adopts Figure 1 The parallel light used in recording is reproduced, and the picture is displayed using a spatial light modulator. The picture is enlarged by a 4f system composed of two lenses. The image is first relayed on a projection scattering screen, and then diffracted into the eyeball through a holographic optical element to form an image. The exposed holographic material only diffracts near the recording wavelength, and other wavelengths are not diffracted and are directly transmitted. In this way, the real scene will also be transmitted into the eyeball, realizing the fusion of virtual scene and real scene, thereby realizing the effect of AR display. In addition, the element can achieve the same focus for the recorded wavelength, thus having the function of a double-cemented lens, realizing the imaging of three wavelengths at the same position of the eyeball, and achieving the effect of achromatism.
[0047] Compared with the existing technology, the achromatic holographic optical element proposed in this embodiment is realized by recording the wavefront of a double-cemented lens. In this way, the holographic optical element has the same wavefront modulation function as a multi-cemented lens, and does not produce chromatic aberration for the three lasers used. At the same time, the three wavelengths of laser use a separate beam expansion system without introducing additional chromatic aberration. The preparation can be completed by using three wavelengths of laser to simultaneously expose a single piece of holographic optical material for a suitable time. The process is simpler, and the molding is formed by one exposure. In addition, the display image can be modulated by cooperating with a spatial light modulator to realize achromatic AR display.
[0048] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.
Claims
1. A system for preparing an achromatic full-color holographic optical element, characterized in that: include: Laser emission assembly, used for simultaneously emitting red, green and blue linearly polarized light; Beam expansion component, used to expand the red, green and blue linear polarized light into the same size; A beam combining and splitting component is used to combine the expanded red, green and blue linearly polarized light into white light, and to split the white light into reference light and signal light; A polarization adjustment component is used to adjust the polarization direction of the reference light so that the polarization of the reference light and the signal light are consistent; A power density adjustment component is used to adjust the polarization directions of the three-color linear polarized light respectively so that the power densities of the blue light, green light and red light components in the reference light and the signal light are equal; The reflective assembly includes a multi-cemented lens, which is used to reflect the signal light and then irradiate it onto the holographic optical element through the multi-cemented lens, and also reflect the reference light and irradiate it onto the holographic optical element, wherein the signal light and the reference light are irradiated onto the same position of the holographic optical element; wherein the exposure dose required for the holographic optical element is set by controlling the opening time of the red, green and blue linear polarized light.
2. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The multi-cemented lens is a doublet lens or a triplet lens.
3. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The exposure dose required for the holographic optical element Q The calculation formula is: Where, P Indicates the power density of signal light or reference light; t Indicates the turn-on time of red, green and blue linear polarized light.
4. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The laser emission component includes three single longitudinal mode lasers: red, green and blue; and the beam expansion component includes three 4f systems.
5. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The beam combining and splitting components include: A first reflector is used to reflect any one of the expanded red, green and blue linearly polarized laser beams to a first dichroic mirror; a first dichroic mirror, configured to reflect one of the remaining two laser beams to a second dichroic mirror, and transmit the laser beam reflected by the first reflector to the second dichroic mirror; a second dichroic mirror, configured to reflect the other of the remaining two laser beams and combine the laser beams reflected and transmitted by the first dichroic mirror into white light; A polarization beam splitter is used to split the white light into reference light and signal light.
6. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The polarization adjustment component includes a first half-wave plate, and the polarization of the reference light and the signal light are made consistent by rotating the first half-wave plate to a direction of 90°; The power density adjustment component includes three second half-wave plates, and the directions of the three second half-wave plates are rotated to make the power densities of the blue light, green light and red light components in the reference light and the signal light equal.
7. The system for preparing an achromatic and full-color holographic optical element according to claim 1, wherein: The reflective component comprises: The second reflecting mirror is used to reflect the signal light and then irradiate the signal light onto the holographic optical element through the multi-cemented lens; The third reflecting mirror is used to reflect the reference light and irradiate it onto the holographic optical element. The signal light and the reference light are irradiated onto the same position on the holographic optical element.
8. A method for preparing an achromatic full-color holographic optical element, characterized in that: The steps include: Emit red, green and blue linearly polarized light; Expand the red, green and blue linear polarized light into the same size; Combining the expanded red, green, and blue linearly polarized light into white light, and splitting the white light into reference light and signal light; Adjust the polarization direction of the reference light so that the polarization of the reference light and the signal light are consistent; Adjust the polarization directions of the three-color linear polarized light respectively so that the power density of the blue light, green light and red light components in the reference light and the signal light are equal; The signal light is reflected and then irradiated onto the holographic optical element through a multi-crystallized lens, and the reference light is also reflected and irradiated onto the holographic optical element. The signal light and the reference light are irradiated onto the same position on the holographic optical element. The exposure dose required for the holographic optical element is set by controlling the opening time of the red, green and blue linear polarized lights.
9. A holographic optical element, characterized in that: The achromatic full-color holographic optical element is prepared by the preparation method of claim 8.
10. Use of the holographic optical element according to claim 9, characterized in that: Used in AR display.