Superlens, superlens array, dodging system and display module

Abstract

The utility model provides a super lens, a super lens array, a dodging system and a display module. The super lens provided by the utility model is used for receiving emitted light of a light source; the light source is a light-emitting diode (LED); the super lens comprises a first area located in the center and a second area located on the periphery. The first area is used for modulating a received light beam in a transmission mode; the second area is used for modulating the received light beam in a reflection mode; the light beam received by the second area is reflected back and forth for at least one time between the second area and a reflecting surface arranged for the second area, and finally the light beam reflected by the second area penetrates through the plane where the super lens is located from the outside of the effective area of the super lens; the light beam projected by the first area and the light beam reflected by the second area jointly form the light beam output by the super lens. According to the super lens, the illumination coverage angle of the super lens for light beams output by light sources such as LEDs can be enlarged, and meanwhile the light energy utilization rate can be increased.

Description

Technical Field

[0001] The present application relates to the field of optics, and specifically to a superlens, a superlens array, a light homogenization system and a display module. Background Art

[0002] Light Emitting Diode (LED) is widely used as a light source due to its high brightness, long life, energy saving and environmental protection. However, the light intensity distribution of the light emitted by LED is uneven, and it cannot be used directly in many scenarios. Therefore, it is necessary to homogenize the light emitted by LED. In the related art, it is proposed to use a super lens to homogenize the light of LED, but the super lens provided by the related art has a small illumination coverage angle for the light beam output by the light source such as LED, and the light energy utilization rate is low. Utility Model Content

[0003] One purpose of the present application is to provide a metalens, a metalens array, a light homogenization system and a display module. The metalens provided in the present application can expand the illumination coverage angle of the light beam output by a light source such as an LED, and at the same time can improve the light energy utilization rate.

[0004] According to one aspect of an embodiment of the present application, a metalens for light homogenization is disclosed, wherein the metalens is used to receive light emitted by a light source and modulate the light emitted by the light source; the light source is a light emitting diode LED;

[0005] The metalens includes a first region located in the center and a second region located in the periphery; the incident angle of the light beam received by the first region is smaller than the incident angle of the light beam received by the second region;

[0006] The first region is used to modulate the received light beam in a transmission manner;

[0007] The second region is used to modulate the received light beam in a reflective manner; the light beam received by the second region is reflected back and forth between the second region and a reflective surface set for the second region at least once, and finally passes through the plane where the metalens is located from outside the effective area of ​​the metalens as the light beam reflected by the second region;

[0008] The light beam projected by the first area and the light beam reflected by the second area together form a light beam output by the super lens.

[0009] In an exemplary embodiment of the present application, the light beam received at each position in the second area is reflected back and forth only once between the second area and the reflective surface.

[0010] In an exemplary embodiment of the present application, the light beam received by at least one position in the second area is reflected back and forth between the second area and the reflective surface at least twice.

[0011] According to one aspect of an embodiment of the present application, a metalens array for light homogenization is disclosed, the metalens array comprising: at least two metalenses provided by any one of the above embodiments;

[0012] The super lens array is used to modulate the emitted light of the light source array; each light source in the light source array is an LED, and the super lenses in the super lens array are matched one by one with the light sources in the light source array;

[0013] The light beam transmitted by the first region of each super lens and the light beam reflected by the second region of each super lens are jointly spliced ​​to form the light beam output by the super lens array.

[0014] In an exemplary embodiment of the present application, the phase distribution of each superlens remains consistent.

[0015] According to one aspect of an embodiment of the present application, a light homogenization system is disclosed, the light homogenization system comprising: a light source array; a super lens array as provided in any of the above embodiments; a reflector;

[0016] The light source array includes at least two light sources, each of which is an LED;

[0017] The reflective plate is arranged for the second area in the metalens, and is used to cooperate with the second area to reflect the light beam received by the second area back and forth.

[0018] In an exemplary embodiment of the present application, the distance between the vertical projection of the center of the light source on the matched metalens and the center of the matched metalens is less than a preset distance threshold.

[0019] In an exemplary embodiment of the present application, the reflective plate is a flat plate structure with a flat surface.

[0020] In an exemplary embodiment of the present application, a concave-convex structure for adjusting the reflection angle is provided on the reflection plate.

[0021] In an exemplary embodiment of the present application, the reflective plate is disposed on the backlight side of the light source array.

[0022] In an exemplary embodiment of the present application, the reflective plate is also used as a substrate of the light source array to at least provide support to the light source array.

[0023] In an exemplary embodiment of the present application, the reflective plate is disposed on the light-emitting side of the light source array; the reflective plate is also used as an aperture to limit the divergence angle range of the light beam received by each superlens.

[0024] According to one aspect of an embodiment of the present application, a display module is disclosed, the display module comprising: a display panel; a light homogenization system as provided in any one of the above embodiments;

[0025] Wherein, the display panel is arranged on the light-emitting side of the light homogenization system, and the display panel includes at least two color display units arranged in an array.

[0026] The metalens provided in the present application includes a first area located in the center and a second area located in the periphery; the incident angle of the light beam received by the first area is smaller than the incident angle of the light beam received by the second area. The first area is used to modulate the received light beam in a transmission manner; the second area is used to modulate the received light beam in a reflection manner; the light beam received by the second area is reflected back and forth at least once between the second area and the reflection surface set for the second area, and finally passes through the plane where the metalens is located from outside the effective area of ​​the metalens as the light beam reflected by the second area.

[0027] Since the peripheral area of ​​the metalens in the present application, i.e., the second area, is reflective, not transmissive, and compared to the transmissive type, the reflective type is easier to provide a large deflection angle to the light beam, therefore, compared to the uniform light device provided by the related art, the metalens array provided by the present application can expand the deflection angle of the edge light beam of the uniform light beam it outputs, and thus can expand the illumination coverage angle of the uniform light beam it outputs. In addition, since the second area is reflective, although the incident angle of the light beam modulated by the second area is large, the light energy utilization rate of the light beam modulated by the second area will not be as serious as that of the transmissive type. In this way, compared to the metalens provided by the related art, the metalens provided by the present application improves the light energy utilization rate of the output light beam. Therefore, the metalens provided by the present application can expand the illumination coverage angle of the light beam output by the light source such as LED, and at the same time can improve the light energy utilization rate.

[0028] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0029] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0031] Figure 1 A schematic diagram of the application of the metalens provided in this application is shown.

[0032] Figure 2 A schematic diagram of the application of the super lens array provided in this application is shown.

[0033] Figure 3 A schematic structural diagram of a reflector in an embodiment of the present application is shown.

[0034] Figure 4 A schematic structural diagram of a reflector in an embodiment of the present application is shown.

[0035] Figure 5 A schematic structural diagram of a reflector in an embodiment of the present application is shown.

[0036] Figure 6 A schematic diagram of the structure of a light homogenization system in an embodiment of the present application is shown.

[0037] Figure 7 A schematic diagram of the structure of a light homogenization system in an embodiment of the present application is shown.

[0038] Figure 8 A schematic diagram of the structure of a light homogenization system in an embodiment of the present application is shown.

[0039] Fig. 9 A schematic diagram of the light spot of the output light beam after a single superlens in the light homogenization system provided in Example 1 of the present application modulates the emitted light of the matched light source is shown.

[0040] Fig.10 Shows Fig. 9 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0041] Fig.11 A schematic diagram of the light spot of the homogenized light beam outputted after the superlens array in the homogenized light system provided in Example 1 of the present application modulates the emitted light of the light source array is shown.

[0042] Fig.12 Shows Fig.11 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0043] Fig.13 A schematic diagram of the light spot of the output light beam after a single superlens in the light homogenization system provided in Example 2 of the present application modulates the emitted light of the matched light source is shown.

[0044] Fig.14 Shows Fig.13The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0045] Fig.15 A schematic diagram of the light spot of the homogenized light beam outputted after the superlens array in the homogenized light system provided in Example 2 of the present application modulates the emitted light of the light source array is shown.

[0046] Fig.16 Shows Fig.15 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0047] Reference numerals:

[0048] 1-superlens array; 11-superlens; 111-first region of superlens; 112-second region of superlens; 2-light source array; 21-light source; 3-reflection surface / reflection plate; 4-target plane / display panel. DETAILED DESCRIPTION

[0049] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0050] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.

[0051] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0052] For light sources such as LEDs, related technologies have proposed a metalens for uniform light: after receiving the emitted light from the light source, the metalens modulates the received light beam in a transmission manner, and then outputs all the received light beams in a transmission manner. By pre-designing the phase distribution of the metalens, the metalens can reorganize the light intensity distribution of the light beam, so that the metalens outputs a light beam with uniform light intensity distribution.

[0053] The light homogenizing device provided by the related art reduces the volume, mass and cost of the light homogenizing device by using a metalens. However, since it uses a fully transmissive metalens, it has the following defects when homogenizing light sources such as LEDs:

[0054] 1. The superlens mainly modulates the light beam through the micro-nano structures set in it. Specifically, the micro-nano structures at various positions provide a certain phase, so a certain phase gradient will be generated between the micro-nano structures at adjacent positions; the generation of the phase gradient can deflect the light beam, thereby realizing the modulation of the light beam.

[0055] It should be noted that, in terms of theoretical design, no matter how large the required deflection angle of the light beam is, as long as the micro-nano structures at the corresponding positions can provide matching phase gradients, it will be fine. However, in the actual processed metalens, the phase gradient that can actually be provided between the micro-nano structures is different from the phase gradient that should be provided in theory during design.

[0056] In detail, when the superlens modulates the light beam in a transmission manner, its micro-nano structure is mainly obtained by processing with all-dielectric materials; the micro-nano structure obtained by processing with all-dielectric materials is similar to a waveguide. Therefore, for the micro-nano structure obtained by processing with all-dielectric materials, the coupling effect between adjacent micro-nano structures will cause the phase actually provided by the micro-nano structure to deviate significantly from the phase that should be provided theoretically, and then cause the phase gradient actually provided between the micro-nano structures to deviate significantly from the phase gradient that should be provided theoretically, thereby causing a significant negative impact on the deflection capability actually provided by the micro-nano structure.

[0057] Moreover, the greater the required deflection angle of the light beam, the greater the phase gradient that the micro-nanostructure needs to provide. For micro-nanostructures made of all-dielectric materials, the greater the required phase gradient, the stronger the coupling effect between the micro-nanostructures, and the greater the negative impact; thus, the gap between the deflection capability actually provided by the micro-nanostructure and the deflection capability that should be provided in theory is greater.

[0058] Therefore, when the metalens modulates the light beam in a transmission manner, the difficulty of the micro-nanostructure in the metalens to deflect the light beam is significantly positively correlated with the deflection angle; that is, when modulating, the larger the deflection angle required for the light beam at a certain position, the greater the difficulty of the micro-nanostructure to deflect the light beam at that position. Therefore, the metalens provided by the related art is difficult to provide a large deflection angle for the light beam, which in turn results in a small illumination coverage angle FOI (Field Of Illumination) of the light beam.

[0059] Second, when the metalens modulates the light beam in a transmission manner, the larger the incident angle of the received light beam, the lower the transmittance of the modulated light beam, and the lower the light energy utilization rate. The divergence angle range of the emitted light of the LED is [-90°, 90°], so the incident angle of the light beam received by the peripheral area of ​​each metalens is relatively large. Therefore, the light energy utilization rate of the metalens provided by the related art is relatively low.

[0060] In summary, the metalens provided by the related art has a small illumination coverage angle for the light beam output by a light source such as LED, and has a low light energy utilization rate.

[0061] In order to overcome the above-mentioned defects of the related art, the present application provides a metalens for light homogenization. The metalens provided in the present application can expand the illumination coverage angle of the light beam output by a light source such as LED, and at the same time can improve the light energy utilization rate.

[0062] Figure 1 Schematic diagram of the application of the metalens provided in this application is shown. Figure 1 The super lens 11 provided in the present application is used to receive the light emitted by the light source 21 and modulate the light emitted by the light source 21 to output a light beam with uniform light intensity distribution. The light source 21 is an LED.

[0063] The superlens 11 includes a substrate and a micro-nano structure; the micro-nano structure is a sub-wavelength structure; the superlens 11 mainly provides corresponding phases at various locations by configuring parameters such as the material, length, height, and arrangement period of the micro-nano structure at various locations, thereby modulating the light beam received at various locations.

[0064] Specifically, the metalens 11 includes a first region 111 located in the center and a second region 112 located in the periphery. The second region 112 is annular, including but not limited to: a circular ring; a ring with an outer circle and an inner square; a square ring; a ring with an outer square and an inner circle. For example, if the metalens 11 is circular and the first region 111 is circular, the second region 112 is annular; if the metalens 11 is circular and the first region 111 is square, the second region 112 is annular.

[0065] In order to facilitate the phase design of the superlens 11, it is necessary to make the light intensity distribution of the light beam received by the superlens 11 symmetrical about the center of the superlens 11; to this end, within the allowable deviation range, the center of the light source 21 is aligned with the center of the matched superlens 11.

[0066] At the same time, the divergence angle range of the emitted light of the LED is [-90°, 90°]. Therefore, when the center of the light source 21 is aligned with the center of the matched superlens 11 within the allowable deviation range, the incident angle of the light beam received by the first area 111 located in the center of the superlens 11 is smaller than the incident angle of the light beam received by the second area 112 located on the periphery.

[0067] In the super lens 11, the first region 111 located in the center is used to modulate the received light beam in a transmission manner. Figure 1 Let’s see: Figure 1 In the figure, the light source 21 is arranged on the left side of the super lens 11; therefore, the emitted light of the light source 21 propagates to the right as a whole, and is then received by the super lens 11; wherein, the light beam received by the first area 111 is transmitted out of the first area 111 after being modulated, and continues to propagate to the right as a whole.

[0068] In the metalens 11, the second region 112 located at the periphery is used to modulate the received light beam by reflection. In order to make the light beam reflected by the second region 112 converge with the light beam transmitted by the first region 111, it is necessary to control the overall propagation direction of the light beam reflected by the second region 112 to be consistent with the overall propagation direction of the light beam transmitted by the first region 111.

[0069] Therefore, a reflective surface 3 is set for the second area 112; the light beam received by the second area 112 is reflected back and forth between the second area 112 and the reflective surface 3 at least once - the light beam received by the second area 112 is first reflected by the second area 112 toward the reflective surface 3, and then reflected by the reflective surface 3 toward the plane where the super lens 11 is located.

[0070] The effective area of ​​the superlens 11 refers to the area in the superlens 11 that can actually modulate the light beam. The substrate edge area where the micro-nano structure is not provided in the superlens 11, and the air area outside the superlens 11 in the plane where the superlens 11 is located, are all outside the effective area of ​​the superlens 11. It can be understood that once the light beam propagating toward the plane where the superlens 11 is located propagates outside the effective area of ​​the superlens 11, it will no longer be reflected, and thus passes through the plane where the superlens 11 is located.

[0071] After the light beam received by the second region 112 is reflected back and forth between the second region 112 and the reflective surface 3 at least once, it will propagate outside the effective area of ​​the metalens 11, and then pass through the plane where the metalens 11 is located from outside the effective area of ​​the metalens 11 as the light beam reflected by the second region 112. In this way, the overall propagation direction of the light beam reflected by the second region 112 is consistent with the overall propagation direction of the light beam transmitted by the first region 111. Figure 1 Let’s see: Figure 1 In the figure, the light beam received by the second area 112 is modulated and reflected by the second area 112, so it propagates to the left as a whole; after propagating to the reflection surface 3, it is reflected by the reflection surface 3, so it propagates to the right as a whole. This is a back and forth reflection. After at least one back and forth reflection, the light beam received by the second area 112 propagates outside the effective area of ​​the metalens 11, and finally passes through the plane where the metalens 11 is located as the light beam reflected by the second area 112, and propagates to the right as a whole; it is consistent with the overall propagation direction of the light beam transmitted by the first area 111.

[0072] The light beam transmitted by the first area 111 obtained by modulation and transmission of the first area 111 and the light beam reflected by the second area 112 obtained by modulation and reflection of the second area 112, these two types of light beams converge to finally form a light beam output by the metalens 11. The light beam output by the metalens 11 can be projected on the target plane 4 to obtain a uniform light spot with uniform light intensity distribution. Among them, the target plane 4 can be a virtual plane for observing the uniform light spot, or it can be an actual plane on the surface of the illumination object or the sensing object.

[0073] According to the above content, it can be seen that the superlens 11 provided in the present application is a superlens that combines transmission and reflection, wherein the first central region 111 is of transmission type and the second peripheral region 112 is of reflection type.

[0074] It should be noted that the illumination coverage angle of the output light beam mainly depends on the deflection angle of the edge light beam of the output light beam. In the present application, the edge light beam of the output light beam is mainly modulated by the peripheral area of ​​the metalens 11, and the peripheral area of ​​the metalens 11 in the present application, that is, the second area 112, is reflective, not transmissive.

[0075] When the superlens 11 modulates the light beam in a reflective manner, its micro-nano structure is mainly obtained by processing metal materials; the micro-nano structure obtained by processing metal materials uses the mutual resonance effect to realize the deflection of the light beam. Therefore, for the micro-nano structure obtained by processing metal materials, the generation of the coupling effect will not have a significant negative impact on the deflection capability actually provided by the micro-nano structure.

[0076] Therefore, when the superlens 11 modulates the light beam in a reflective manner, the difficulty of the micro-nano structure in the superlens 11 to deflect the light beam does not increase significantly due to the increase in the deflection angle; therefore, compared with the transmission type, the reflection type is easier to provide a large deflection angle to the light beam; in this way, compared with the superlens provided by the related art, the superlens 11 provided in the present application can expand the deflection angle of the edge light beam of the light beam it outputs, and thus can expand the illumination coverage angle of the light beam it outputs.

[0077] It should also be noted that, since the second region 112 is reflective, although the incident angle of the light beam modulated by the second region 112 is large, the light energy utilization rate of the light beam modulated by the second region 112 will not be severely reduced as in the case of a transmissive type. In this way, compared with the metalens provided by the related art, the metalens 1 provided by the present application improves the light energy utilization rate of the output light beam.

[0078] In summary, it can be seen that the superlens 11 provided in the present application can expand the illumination coverage angle of the light beam output by a light source such as an LED, and at the same time can improve the utilization rate of light energy.

[0079] In one embodiment, the light beam received at each position in the second area 112 is reflected back and forth only once between the second area 112 and the reflective surface 3 .

[0080] Specifically, each position in the second region 112 will receive the light beam emitted by the light source 21, so each position in the second region 112 will reflect the received light beam. In this embodiment, by configuring the phase of the micro-nano structure at each position in the second region 112, the distance between the metalens 11 and the reflecting surface 3, and the surface morphology of the reflecting surface 3, the light beam received at each position in the second region 112 is reflected once by the second region 12, and then reflected once by the reflecting surface 3, and then passes through the plane where the metalens 11 is located from outside the effective area of ​​the metalens 11.

[0081] In this embodiment, since the light beam received at each position in the second area 112 is only reflected back and forth once between the second area 112 and the reflective surface 3, the micro-nano structure at each position in the second area 112 only needs to modulate once for the light beam directly from the light source 21. Since the modulation object is single, the phase required to be provided by the micro-nano structure at each position in the second area 112 can be positively analyzed based on the metasurface theory, which is conducive to reducing the difficulty of phase analysis and improving the robustness of the analyzed phase.

[0082] In one embodiment, the light beam received at at least one position in the second area 112 is reflected back and forth between the second area 112 and the reflective surface 3 at least twice.

[0083] Specifically, in this embodiment, by configuring the phase of the micro-nano structure at each position in the second region 112, the distance between the metalens 11 and the reflecting surface 3, and the surface morphology of the reflecting surface 3, the light beam received at at least one position in the second region 112 is reflected back and forth by the second region 112 and the reflecting surface 3 at least twice before passing through the plane where the metalens 11 is located from outside the effective area of ​​the metalens 11.

[0084] Compared with a light beam that is reflected back and forth only once, the reflection path of a light beam that is reflected back and forth at least twice can be modulated more precisely, thereby facilitating improvement of the uniformity of the homogenized light beam.

[0085] The present application also provides a super lens array for light homogenization. Figure 2 Schematic diagram of the application of the metalens array provided by the present application is shown. Figure 2 The metalens array 1 provided in the present application includes: at least two metalens 11 provided in any of the above embodiments. Referring to the description of the metalens 11 in any of the above embodiments, the details of the metalens 11 are not repeated here.

[0086] The metalens array 1 provided in the present application is used to modulate the emitted light of the light source array 2. Each light source 21 in the light source array 2 is an LED, and the metalens 11 in the metalens array 1 is matched with the light sources 21 in the light source array 2 one by one.

[0087] The first area 111 of each superlens 11 modulates the received light beam in a transmission manner to obtain the transmitted light beam of the first area 111; the second area 112 of each superlens 11 modulates the received light beam in a reflection manner, and cooperates with the reflecting surface 3 to obtain the reflected light beam of the second area 112. Finally, the transmitted light beam of the first area 111 of each superlens 11 and the reflected light beam of the second area 112 of each superlens 11 are spliced ​​together to form the light beam output by the superlens array 1. Among them, the light beam output by the superlens array 1 can be projected on the target plane 4 to obtain a uniform light spot with uniform light intensity distribution. Compared with a single superlens 11, the light beam output by the superlens array 1 can provide a larger coverage area.

[0088] In one embodiment, there are certain differences in the phase distributions of different superlenses 11 in the superlens array 1; in particular, there are differences in the phase distributions of the superlenses 11 located in the edge area of ​​the superlens array 1 and the superlenses 11 located in the hinterland area of ​​the superlens array 1.

[0089] It can be understood that for the metalens 11 located in the edge area of ​​the metalens array 1, the light beam emitted from at least one side does not intersect with the light beam emitted from any other metalens 11; while for the metalens 11 located in the hinterland area of ​​the metalens array 1, the light beam emitted from each side intersects with the light beam emitted from other metalens 11.

[0090] Therefore, when designing the phase distribution of each superlens 11, the phase distribution of the superlens 11 located in the hinterland area of ​​the superlens array 1 can be configured differently from the phase distribution of the superlens 11 located in the edge area of ​​the superlens array 1, so as to improve the light intensity uniformity at the edge position of the uniform light beam output by the superlens array 1.

[0091] In one embodiment, the phase distribution of each metalens 11 in the metalens array 1 remains consistent. It can be understood that when the phase distribution of each metalens 11 remains consistent, when designing the phase distribution of each metalens 11, it is only necessary to design the phase distribution of one metalens 11, and then optimize its phase distribution according to the array arrangement; and when manufacturing the metalens array 1, it is only necessary to process one type of metalens 11. In this way, on the one hand, the difficulty of phase design and optimization is reduced, and on the other hand, the processing complexity is reduced.

[0092] The phase distribution of the super lens array 1 provided in the present application can be configured in the following manner:

[0093] The emitted light of LED is incoherent light, and its light intensity distribution basically follows the Lambertian distribution, and its divergence angle range is [-90°, 90°], which is difficult to simulate accurately. To this end, a point light source model can be used to replace the light source 21, and the initial phase distribution of the superlens 11 can be designed based on the point light source model, and then the initial phase distribution is optimized, and finally a phase distribution that can output a uniform light beam that meets the requirements at the array level is obtained.

[0094] Specifically, first, the following parameters are determined: the distance between the light source array 2 and the super lens array 1; the distance between the reflecting surface 3 and the super lens array 1; the number, size, and arrangement interval of the light sources 21; the number, size, and arrangement interval of the super lenses 11; the shape and size of the first area 111 in the super lens 11; the shape and size of the second area 112 in the super lens 11; and the splicing size that the uniform light beam output by the super lens array 1 should have on the target plane.

[0095] Then, according to the point light source model, the intensity distribution of the light beam received by the superlens 11 and the incident angle of the light beam at each position are determined when the emitted light of the light source 21 irradiates the matched superlens 11. At the same time, according to the splicing size that the uniform light beam should have on the target plane and the number of superlenses 11, the size of the light beam output by a superlens 11 on the target plane is determined; according to the size of the light beam output by the superlens 11 on the target plane, the intensity distribution of the light beam output by the superlens 11 can be determined.

[0096] According to the law of conservation of energy, the intensity distribution of the light beam received by the superlens 11 is mapped to the intensity distribution of the light beam output by the superlens 11, so the emission angle of the light beam at each position of the superlens 11 can be determined. By applying the generalized Snell's law, the phase at each position of the superlens 11 can be analytically obtained according to the incident angle and the emission angle of the light beam at each position of the superlens 11, and thus the initial phase distribution of the superlens 11 is obtained.

[0097] Since the light beams output by the superlens 11 need to be spliced ​​together, the cross-sectional shape of the light beams output by each superlens 11 is preferably rectangular in order to facilitate light homogenization. In this case, the phase distribution of the superlens 11 is non-circularly symmetric; therefore, the initial phase distribution of the superlens 11 is fitted using the following two-dimensional parameter polynomial formula:

[0098]

[0099] Wherein, x represents the coordinate of a certain position in the superlens 11 in the x direction, and y represents the coordinate of the corresponding position in the superlens 11 in the y direction. The x direction and the y direction can together constitute a two-dimensional plane where the superlens 11 is located; represents the phase provided at the corresponding position in the super lens 11; c 00 represents the coefficient of the constant term; c 10 represents the coefficient of the first-order term in the x direction and the zero-order term in the y direction; c 01 represents the coefficient of the zero-order term in the x direction and the first-order term in the y direction; c 11 Represents the coefficient of the first-order term in the x-direction and the first-order term in the y-direction; and so on.

[0100] Since the light modulation mode of the first region 111 in the metalens 11 is different from the light modulation mode of the second region 112, the two sets of the above polynomial formulas are used to fit the initial phase distribution of the metalens 11. The two sets of polynomial formulas can share the same initial value of the phase coefficient when describing the initial phase distribution of the metalens 11, but in the subsequent phase optimization process, the respective phase coefficients are optimized separately.

[0101] Then, the optical simulation software is used to simulate the optical system composed of the reflective surface 3, the light source array 2 and the superlens array 1 to confirm the light intensity distribution of the light beam output by the superlens array 1 on the target plane 4 under the effect of the phase distribution provided by the superlens 11. The phase distribution of the superlens 11 can be characterized by its corresponding phase coefficients; these phase coefficients are configured as adjustable variables for subsequent optimization.

[0102] If the intensity distribution of the light beam output by the superlens array 1 obtained by simulation does not meet the light homogenization requirement, the phase coefficient can be modified by applying a local optimization strategy or a global optimization strategy to optimize the phase distribution of the superlens 11. Then simulate again and confirm again whether the intensity distribution of the light beam output by the superlens array 1 obtained by simulation meets the light homogenization requirement. Continue to iterate until the intensity distribution of the light beam output by the superlens array 1 obtained by simulation meets the light homogenization requirement, thereby obtaining the phase distribution of the usable superlens 11, and thus obtaining the phase distribution of the superlens array 1.

[0103] The present application also provides a light homogenization system. Figure 2 The light homogenization system provided in the present application includes: a light source array 2; a super lens array 1 as provided in any of the above embodiments; and a reflector 3.

[0104] The light source array 2 includes at least two light sources 21 , and each light source 21 is an LED.

[0105] Refer to the description of the super lens array 1 in any of the above embodiments, and the detailed details of the super lens array 1 will not be repeated here.

[0106] The reflector 3 is set for the second area 112 in the metalens 11, and it plays the role of the reflective surface 3, which is used to cooperate with the second area 112 to reflect the light beam received by the second area 112 back and forth, and finally obtain the light beam reflected from the second area 112 outside the effective area of ​​the metalens 11 through the plane where the metalens array 1 is located. Therefore, the light beam reflected by the second area 112 of each metalens 11 is spliced ​​with the light beam projected by the first area 111 of each metalens 11 to obtain the uniform light beam output by the metalens array 1.

[0107] In order to facilitate the phase design of the metalens 11, it is necessary to make the light intensity distribution of the light beam received by the metalens 11 symmetrical about the center of the metalens 11; considering the processing error of the light source 21 and the required tolerance, in one embodiment, the distance between the vertical projection of the center of the light source 21 on the matched metalens 11 and the center of the matched metalens 11 is less than a preset distance threshold. That is, within the deviation range allowed by the distance threshold, the center of the light source 21 is aligned with the center of the matched metalens 11.

[0108] Figure 3 FIG. 2 shows a schematic diagram of the structure of the reflector 3 in an embodiment of the present application. Figure 3 In one embodiment, the reflector 3 is a flat plate structure with a flat surface.

[0109] Specifically, when the reflector 3 is a flat plate structure with a flat surface, if a certain position on the second region 112 of the superlens 11 provides a deflection angle of θ0 for the received light beam, when the light beam is reflected to the reflector 3, its incident angle relative to the reflector 3 is θ0; therefore, after the light beam is reflected again by the reflector 3, its reflection angle relative to the reflector 3 is θ0.

[0110] In this embodiment, by setting the reflector 3 as a flat plate structure with a flat surface, the structural complexity of the reflector 3 is reduced, thereby helping to reduce the manufacturing cost of the reflector 3 .

[0111] Figure 4 A schematic structural diagram of a reflector 3 in an embodiment of the present application is shown. Figure 5 A schematic structural diagram of a reflector 3 in another embodiment of the present application is shown.

[0112] See also Figure 4 and Figure 5 In one embodiment, the reflective plate 3 is provided with a concave-convex structure for adjusting the reflection angle.

[0113] Specifically, Figure 4 As shown, when a protruding structure protruding toward the super lens 11 is provided on the reflector 3, if a certain position on the second region 112 of the super lens 11 provides a deflection angle of θ0 for the received light beam, when the light beam is reflected to the protruding structure, its incident angle relative to the protruding structure is θ1; therefore, after the light beam is reflected again by the protruding structure, its reflection angle relative to the protruding structure is θ1. Obviously, θ1 is greater than θ0; and when the plane excluding the protruding structure in the reflector 3 is used as the reference plane to determine the reflection angle of the light beam relative to the reflector 3, the inclination angle of the protruding structure relative to the reference plane should be added to θ1; in this way, the reflection angle of the light beam relative to the reflector 3 exceeds θ0 more. It can be seen that by providing a protruding structure protruding toward the super lens 11 on the reflector 3, the reflection angle of the local light beam can be increased.

[0114] like Figure 5As shown, when a concave structure concave toward the super lens 11 is provided on the reflector 3, if a certain position on the second region 112 of the super lens 11 provides a deflection angle of θ0 for the received light beam, when the light beam is reflected to the convex structure, its incident angle relative to the concave structure is θ2; therefore, after the light beam is reflected by the concave structure again, its reflection angle relative to the concave structure is θ2. Obviously, θ2 is smaller than θ0; and when the plane excluding the concave structure in the reflector 3 is used as the reference plane to determine the reflection angle of the light beam relative to the reflector 3, the inclination angle of the convex structure relative to the reference plane should be subtracted from θ2; in this way, the reflection angle of the light beam relative to the reflector 3 is smaller than θ0. It can be seen that by providing a concave structure concave toward the super lens 11 on the reflector 3, the reflection angle of the local light beam can be reduced.

[0115] It should be noted that whether to set the concave-convex structure on the reflector 3 and how to set the concave-convex structure mainly depends on the light uniformity requirement.

[0116] Specifically, in order to reduce the difficulty of phase resolution and improve the robustness of the resolved phase, it is required that the light beam received at each position in the second area 112 is reflected back and forth only once between the second area 112 and the reflector 3. However, it is difficult to achieve this due to the limitation of the deflection angle that the micro-nano structure can provide based on the reflector 3 with a flat surface. In this case, a protruding structure can be provided on the reflector 3 for the light beam with insufficient deflection angle, so as to actively increase the reflection angle of the corresponding light beam, thereby compensating for the insufficient deflection ability of the micro-nano structure.

[0117] In order to more precisely modulate the reflection path of the light beam, it is required that the light beam received at at least one position in the second area 112 be reflected back and forth between the second area 112 and the reflecting plate 3 at least twice; in this case, assuming that the sub-area A in the second area 112 needs to receive the light beam reflected back from the reflecting plate 3, and in response to the change in the uniform light demand, the incident angle of the light beam received by the sub-area A from the reflecting plate 3 needs to be reduced. Then, a recessed structure can be set on the reflecting plate 3 for the light beam that the sub-area A should receive from the reflecting plate 3, so as to actively reduce the reflection angle of the corresponding light beam, so that at least there is no need to change the phase of the micro-nano structure located upstream of the propagation path of the light beam, thereby minimizing the impact of the change in the uniform light demand on the micro-nano structure in the area outside the sub-area A.

[0118] In one embodiment, the reflective plate 3 is disposed on the backlight side of the light source array 2 .

[0119] Figure 6 FIG. 2 shows a schematic diagram of the structure of a light homogenization system in an embodiment of the present application. Figure 6In one embodiment, the reflective plate 3 is disposed on the backlight side of the light source array 2 , and a certain distance is provided between the reflective plate 3 and the light source array 2 .

[0120] Figure 7 FIG. 2 shows a schematic diagram of the structure of a light homogenization system in an embodiment of the present application. Figure 7 In one embodiment, the reflector 3 is disposed on the backlight side of the light source array 2, and the light source array 2 is disposed on the reflector 3. In this case, in addition to being used to cooperate with the second area 112 to reflect the light beam back and forth, the reflector 3 is also used as a substrate of the light source array 2, thereby at least providing support to the light source array 2. By arranging circuit elements in the reflector 3, the reflector 3 can also provide power or control signals to the light source array 2.

[0121] It can be seen that the design provided in this embodiment can improve the integration of the light homogenization system, which is beneficial to reducing the volume and weight of the light homogenization system.

[0122] It should be noted that the divergence angle range of the emitted light of the LED is [-90°, 90°], so each metalens 11 will not only receive the emitted light of the matched light source 21, but also the emitted light of other light sources 21. However, in order to simplify the design, when designing the phase of the metalens 11, it is usually assumed that the metalens 11 only receives the emitted light of the matched light source 21. As a result, the light beam reception condition of the metalens 11 assumed during the design is somewhat different from the actual light beam reception condition of the metalens 11, which makes the designed phase easily deviate, and further leads to low efficiency of phase design optimization.

[0123] Therefore, in order to improve the design optimization efficiency of the phase, in one embodiment, the reflector 3 is disposed on the light-emitting side of the light source array 2. In addition to being used to cooperate with the second area 112 to reflect the light beam back and forth, the reflector 3 is also used as an aperture to limit the divergence angle range of the light beam received by each super lens 11.

[0124] Figure 8 FIG. 2 shows a schematic diagram of the structure of a light homogenization system in an embodiment of the present application. Figure 8 As shown, in one embodiment, the reflector 3 is disposed between the light source array 2 and the super lens array 1. At the same time, a hole structure can be provided on the reflector 3 to form an aperture, so that the light emitted by the light source 21 can pass through the hole structure of the reflector 3 only within a certain divergence angle range, and thus each super lens 11 basically only receives the light emitted by the matched light source 21.

[0125] In this way, the discrepancy between the light beam reception condition of the metalens 11 assumed during design and the actual light beam reception condition of the metalens 11 is reduced, thereby reducing the degree of deviation of the designed phase and further improving the design optimization efficiency of the phase.

[0126] The present application also provides a display module. Figure 2 When the target plane 4 in represents the display panel, Figure 2 The structure diagram of the display module is also shown. Figure 2 The display module provided in the present application includes: a display panel 4; and a light homogenization system as provided in any of the above embodiments.

[0127] The display panel 4 is arranged on the light output side of the light homogenization system, and is used to receive the light beam with uniform light intensity output by the light homogenization system. The display panel 4 includes at least two color rendering units arranged in an array. The color rendering unit refers to a light-emitting unit corresponding to a single image channel. For example: if the display module uses the RGB mode to display an image, each pixel includes at least one color rendering unit corresponding to the R image channel, at least one color rendering unit corresponding to the G image channel, and at least one color rendering unit corresponding to the B image channel.

[0128] Under the action of the light beam output by the light homogenization system, the display panel 4 can display images. Please refer to the description of the light homogenization system in any of the above embodiments, and the details of the light homogenization system will not be repeated here.

[0129] Compared with the light homogenization system using the traditional refractive lens array for light homogenization, the light homogenization system provided by the present application uses the super lens array 1 as a light homogenization device, so the light homogenization system provided by the present application can greatly reduce its distance in the optical axis direction and greatly reduce its weight. Therefore, the thickness and weight of the display module provided by the present application can be greatly reduced, which is conducive to realizing the thinness of the display module.

[0130] Example 1

[0131] In Example 1, the size of the light source array 2 is 500μm*500μm, and the central wavelength of the emitted light is 455nm; the light source array 2 is arranged on the reflecting surface 3; the light source array 2 includes 5*5 light sources 21, and the arrangement period of the light sources 21 is 6mm; the superlens array 1 includes 5*5 superlenses 11, and the arrangement period of the superlens 111 is 6mm; the distance from the light source 21 to the base of the superlens 11 is 0.75mm, the thickness of the base of the superlens 11 is 300μm, and the distance from the base of the superlens 11 to the target plane 4 is 1.95mm.

[0132] After designing and optimizing the phase of the super lens array 1, a light homogenization system that meets the light homogenization requirements is obtained.

[0133] Specifically, Fig. 9 The schematic diagram shows the spot of the output light beam after the single super lens 11 in the light homogenization system provided in Example 1 modulates the emitted light of the matched light source 21. Fig.10 Shows Fig. 9 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0134] according to Fig. 9 and Fig.10 It can be seen that in the optimized light homogenization system, the light intensity distribution of the light beam output by the single superlens 11 for the emission light of the matched light source 21 is very uniform.

[0135] Fig.11 The schematic diagram shows the light spot of the homogenized light beam outputted after the super lens array 1 in the homogenized light system provided in Example 1 modulates the emitted light of the light source array 2. Fig.12 Shows Fig.11 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0136] according to Fig.11 and Fig.12 It can be seen that in the optimized uniform light system, the uniform light beam output by the superlens array 1 for the emitted light of the light source array 2 has a very high light intensity uniformity, and the light intensity at the joint of the light beams output by different superlenses 21 does not change significantly, which is very beneficial for lighting or display.

[0137] Example 2

[0138] In Example 2, the size of the light source array 2 is 500μm*500μm, and the central wavelength of the emitted light is 455nm; the light source array 2 is arranged on the reflecting surface 3; the light source array 2 includes 5*5 light sources 21, and the arrangement period of the light sources 21 is 6mm; the superlens array 1 includes 5*5 superlenses 11, and the arrangement period of the superlens 111 is 6mm; the distance from the light source 21 to the base of the superlens 11 is 1mm, the thickness of the base of the superlens 11 is 300μm, and the distance from the base of the superlens 11 to the target plane 4 is 3.7mm.

[0139] After designing and optimizing the phase of the super lens array 1, a light homogenization system that meets the light homogenization requirements is obtained.

[0140] Specifically, Fig.13 A schematic diagram of the light spot of the output light beam after a single superlens 11 in the light homogenization system provided in Example 2 modulates the emitted light of the matched light source 21 is shown. Fig.14 Shows Fig.13 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0141] according to Fig.13 and Fig.14 It can be seen that in the optimized light homogenization system, the light intensity distribution of the light beam output by the single superlens 11 for the emission light of the matched light source 21 is very uniform.

[0142] Fig.15 The schematic diagram shows the spot of the homogenized light beam outputted after the super lens array 1 in the homogenized light system provided in Example 2 modulates the emitted light of the light source array 2. Fig.16 Shows Fig.15 The shown normalized light intensity distribution curve of the light spot on the x=0 section line and the normalized light intensity distribution curve on the y=0 section line.

[0143] according to Fig.15 and Fig.16 It can be seen that in the optimized uniform light system, the uniform light beam output by the superlens array 1 for the emitted light of the light source array 2 has a very high light intensity uniformity, and the light intensity at the joint of the light beams output by different superlenses 21 does not change significantly, which is very beneficial for lighting or display.

[0144] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A metalens for light homogenization, characterized in that: The super lens is used to receive the emitted light of the light source and modulate the emitted light of the light source; the light source is a light emitting diode LED; The metalens includes a first region located in the center and a second region located in the periphery; the incident angle of the light beam received by the first region is smaller than the incident angle of the light beam received by the second region; The first region is used to modulate the received light beam in a transmission manner; The second region is used to modulate the received light beam in a reflective manner; the light beam received by the second region is reflected back and forth between the second region and a reflective surface set for the second region at least once, and finally passes through the plane where the metalens is located from outside the effective area of ​​the metalens as the light beam reflected by the second region; The light beam projected by the first area and the light beam reflected by the second area together form a light beam output by the super lens.

2. The metalens according to claim 1, characterized in that The light beam received at each position in the second area is reflected back and forth between the second area and the reflective surface only once.

3. The metalens according to claim 1, characterized in that The light beam received at at least one position in the second area is reflected back and forth between the second area and the reflective surface at least twice.

4. A superlens array for light homogenization, characterized in that: The superlens array comprises: at least two superlenses as described in any one of claims 1 to 3 above; The super lens array is used to modulate the emitted light of the light source array; each light source in the light source array is an LED, and the super lenses in the super lens array are matched one by one with the light sources in the light source array; The light beam transmitted by the first region of each super lens and the light beam reflected by the second region of each super lens are jointly spliced ​​to form the light beam output by the super lens array.

5. The super lens array according to claim 4, characterized in that: The phase distribution of each metalens remains consistent.

6. A light homogenization system, characterized in that: The light homogenization system comprises: a light source array; a super lens array as described in any one of claims 4 to 5; a reflector; The light source array includes at least two light sources, each of which is an LED; The reflective plate is arranged for the second area in the metalens, and is used to cooperate with the second area to reflect the light beam received by the second area back and forth.

7. The light homogenization system according to claim 6, characterized in that: The distance between the vertical projection of the center of the light source on the matched metalens and the center of the matched metalens is less than a preset distance threshold.

8. The light homogenization system according to claim 6, characterized in that: The reflecting plate is a flat plate structure with a flat surface.

9. The light homogenization system according to claim 6, characterized in that: The reflective plate is provided with a concave-convex structure for adjusting the reflection angle.

10. The light homogenization system according to claim 6, characterized in that: The reflector is arranged on the backlight side of the light source array.

11. The light homogenization system according to claim 10, characterized in that: The reflective plate also serves as a substrate of the light source array to at least provide support to the light source array.

12. The light homogenization system according to claim 6, characterized in that: The reflector is arranged on the light-emitting side of the light source array; the reflector is also used as an aperture to limit the divergence angle range of the light beam received by each super lens.

13. A display module, characterized in that: The display module comprises: a display panel; a light homogenization system as described in any one of claims 6 to 12; Wherein, the display panel is arranged on the light-emitting side of the light homogenization system, and the display panel includes at least two color display units arranged in an array.

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