CN115755238A - Multilayer micro-lens array dodging structure and design method thereof, TOF lens and device - Google Patents

Abstract

The invention discloses a multilayer micro-lens array light homogenizing structure and a design method thereof, a TOF lens and equipment, wherein the multilayer micro-lens array light homogenizing structure comprises at least two layers of micro-lens arrays, each layer of micro-lens array is formed by arranging a plurality of sub-lenses, and the optical surface types of the sub-lenses forming one layer of micro-lens array are the same; at least one layer of the micro lens array consists of a plurality of even-order aspheric surface type sub lenses, and the sub lenses are arranged in a staggered way to form the micro lens array; at least one layer of the micro lens array is composed of a plurality of deformed aspheric surface type sub lenses, and the sub lens arrays are arranged to form the micro lens array. The light homogenizing structure consists of at least two layers of micro lens arrays, each layer of micro lens array has a certain diffusion effect on light emitted by a laser array light source, and expected light spots and expected energy distribution are formed by superposition of the diffusion effects caused by the multiple layers of micro lens arrays.

Description

Multilayer micro-lens array dodging structure and design method thereof, TOF lens and device

Technical Field

The invention relates to the field of three-dimensional sensing, in particular to a multilayer micro-lens array dodging structure and a design method thereof, a TOF lens and a device.

Background

TOF (Time of flight) technology can perform three-dimensional sensing and distance measurement, and the optical part of TOF is mainly divided into three parts: the device comprises a laser array light source, a dodging structure and a TOF lens.

Because the shape, the field angle and the energy distribution of the dodging light spots to be achieved by the micro lens array in the dodging structure are specific, the field angle achieved by the existing array laser source after passing through the micro lens array is relatively small, and a large detection range cannot be met.

After the laser array light source passes through the existing micro-lens array, interference fringes can appear in finally formed light spots because the coherence of light emitted by the array laser light source cannot be eliminated by the micro-lens array.

The existing micro-lens array has high design and processing difficulty, and is difficult to manufacture a uniform light structure which has a large field angle, no interference fringes and a good optical effect.

Therefore, a new technical solution is needed to solve the above problems.

Disclosure of Invention

The invention aims to solve the problems that the existing dodging device has interference fringes on a laser light source, and has a small field angle and high processing difficulty. On one hand, a multilayer micro-lens array dodging structure is provided, and the specific technical scheme is as follows:

a multilayer micro-lens array light homogenizing structure comprises at least two layers of micro-lens arrays, wherein each layer of micro-lens array is formed by arranging a plurality of sub-lenses, and the optical surface types of the sub-lenses forming the same layer of micro-lens array are the same.

In the above technical solution, a plurality of sub-lenses are arranged in a staggered manner to form a microlens array, and in the microlens array, a ratio of a maximum value to a minimum value of a center distance between two adjacent sub-lenses is not more than three-half.

In a preferred embodiment, further, at least one layer of the microlens array is composed of a plurality of even-order aspheric surface type sub-lenses, and a plurality of the sub-lenses are arranged in a staggered manner to form the microlens array.

Still further, the range of the curvature radius of the sub-lenses of the plurality of even-order aspheric surface types forming the micro-lens array is 30-100 μm, and the range of the cone coefficient is-1 to-1.2.

Furthermore, the curvature radius of the sub-lenses of the even-order aspheric surface types composing the micro-lens array ranges from 20 μm to 40 μm, and the cone coefficient ranges from-1 to-1.2.

In a preferred embodiment, at least one layer of the microlens array is composed of a plurality of sub-lenses of an anamorphic aspheric surface type, and a plurality of the sub-lens arrays are arranged to form the microlens array.

Still further, the range of the curvature radius of the sub-lenses of the plurality of anamorphic aspheric surface types constituting the microlens array in the first coordinate direction is 10 μm to 15 μm, the range of the curvature radius of the sub-lenses in the second coordinate direction is 6 μm to 15 μm, the range of the conic coefficient of the plurality of sub-lenses is-1 to-1.2, and the range of the center distance between any two adjacent sub-lenses is 25 μm to 45 μm.

Furthermore, the curvature radius of the sub-lenses of the deformed aspheric surface type forming the micro-lens array is 10-20 μm, the cone coefficient of the sub-lenses is-1-1.2, and the center distance between any two adjacent sub-lenses is 25-45 μm.

In a preferred embodiment, further, the multilayer microlens array light homogenizing structure comprises two layers of microlens arrays, one layer of microlens array is composed of a plurality of even-order aspheric surface type sub-lenses which are arranged in a staggered manner, the curvature radius of the plurality of sub-lenses composing the layer of microlens array ranges from 30 μm to 100 μm, and the cone coefficient ranges from-1 to-1.2;

furthermore, the microlens array of the other layer is formed by arranging a plurality of sub-lens arrays of deformed aspheric surface shapes, the central distance between any two adjacent sub-lenses ranges from 25 micrometers to 45 micrometers, the curvature radius of the sub-lenses of the deformed aspheric surface shapes forming the microlens array ranges from 10 micrometers to 15 micrometers in the transverse coordinate direction, the curvature radius of the sub-lenses in the longitudinal coordinate direction ranges from 6 micrometers to 15 micrometers, and the cone coefficients of the sub-lenses range from-1 to-1.2.

In a preferred embodiment, further, the multilayer microlens array light homogenizing structure comprises a three-layer microlens array, the first layer of microlens array is composed of a plurality of even-order aspheric surface type sub-lenses which are arranged in a staggered manner, the curvature radius of the plurality of sub-lenses which form the layer of microlens array ranges from 30 μm to 100 μm, and the cone coefficient ranges from-1 to-1.2;

still further, the second layer of the micro lens array is composed of a plurality of even-order aspheric surface type sub lenses which are arranged in a staggered mode, the curvature radius range of the sub lenses forming the layer of the micro lens array is 20-40 mu m, and the cone coefficient range is-1-1.2;

furthermore, the micro lens array of the third layer is composed of a plurality of sub lens arrays of deformed aspheric surface shapes, the central distance between any two adjacent sub lenses ranges from 25 micrometers to 45 micrometers, the curvature radius of the sub lenses of the plurality of deformed aspheric surface shapes forming the micro lens array ranges from 10 micrometers to 20 micrometers, and the cone coefficient of the plurality of sub lenses ranges from-1 to-1.2.

In a preferred embodiment, the micro-lens array further comprises a substrate layer and a light homogenizing layer formed on the surface of the substrate layer, wherein the surface of the light homogenizing layer, which faces away from the substrate layer, is formed with the micro-lens array; the micro lens array forms a continuous surface on the surface of the light homogenizing layer.

Furthermore, the base layer of one layer of the microlens array and the base layer of the other layer of the microlens array adjacent to the microlens array are arranged oppositely at intervals, and the distance between the microlens array and the base layer of the other layer of the microlens array adjacent to the microlens array is in the range of 0.1 mm-0.3 mm.

Further, the optical surface shapes of the sub-lenses constituting the microlens array include aspherical surface shapes.

Furthermore, the thickness of each layer of the micro lens array ranges from 0.2mm to 0.5mm.

In another aspect, the present invention further provides a method for designing a light uniformizing structure of a multi-layer microlens array, which includes: arranging a plurality of sub-lens arrays, and determining the center distance between any two adjacent sub-lenses according to expected light spots; and offsetting each sub-lens on the plane on which the sub-lens is positioned by a preset distance by taking the central point of each sub-lens as an initial point, and removing the intersected part of two adjacent sub-lenses to obtain the micro-lens array.

In a preferred embodiment, the center-to-center distance between any two adjacent sub-lenses is in a range of 25 μm to 45 μm.

In a preferred embodiment, each sub-lens is shifted by a preset distance on a plane on which the sub-lens is located, with a central point of the sub-lens as an initial point, a maximum value of the preset distance for shifting each sub-lens is 0.1 times of a center-to-center distance between the sub-lens at the initial point and the sub-lens adjacent to the sub-lens, and a minimum value of the preset distance for shifting each sub-lens is 0.

In another aspect, the invention further provides a TOF lens, which comprises the multilayer microlens array dodging structure, wherein the multilayer microlens array dodging structure comprises at least two layers of microlens arrays, and an air layer with a thickness ranging from 0.1mm to 0.5mm is arranged between the microlens array close to the laser array light source and the laser array light source.

In another aspect, the invention further provides a device equipped with a TOF lens, which includes the TOF lens, and the TOF lens is equipped with the multilayer microlens array dodging structure.

Compared with the prior art, the invention has one or more of the following beneficial effects:

1. the multilayer micro-lens array light homogenizing structure provided by the invention comprises two or more layers of micro-lens arrays, each layer of micro-lens array has a certain diffusion effect on light emitted by a laser array light source, and expected light spots and expected energy distribution are formed by overlapping the diffusion effects caused by the multilayer micro-lens arrays.

2. According to the multilayer micro-lens array light homogenizing structure provided by the invention, at least one layer of micro-lens array in the multilayer micro-lens array can carry out irregular staggered arrangement on the sub-lenses, so that the coherence of light rays of a laser array light source after penetrating through the micro-lens array is further destroyed, and the interference fringes of light spots are eliminated.

3. The microlens arrays of all layers in the multilayer microlens array light uniformizing structure are closely arranged, the curvature radius of the sub-lenses in each microlens array is large, the rise is low, the processing is easy, and the processing difficulty and the processing error are reduced.

4. The multilayer micro-lens array dodging structure provided by the invention can enable light emitted by the laser array to obtain a larger field angle after passing through the multilayer micro-lens array dodging structure under the condition that the curvature radius of the sub-lens is larger, so that a TOF module can detect more areas.

5. In the multilayer micro-lens array dodging structure provided by the invention, the sub-lenses of each layer are not in fault and are in smooth transition, a continuous surface is formed, and the light transmittance and the embossing yield in the processing process are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a light homogenizing structure with two layers of microlens arrays;

FIG. 2 is a side view of a two-layer microlens array structure;

FIG. 3 is a front view of one layer of a microlens array in a two-layer microlens array structure;

FIG. 4 is an enlarged view of a portion of the microlens array shown in FIG. 3;

FIG. 5 is a front view of another layer of microlens array in a two-layer microlens array structure;

FIG. 6 (a) is a schematic diagram of far field emergent light spots of a multilayer microlens array uniform light structure;

FIG. 6 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in FIG. 6 (a);

FIG. 7 is a side view of a two layer microlens array structure;

FIG. 8 is a front view of one layer of a microlens array in a two-layer microlens array structure;

FIG. 9 is an enlarged view of a portion of the microlens array shown in FIG. 8;

FIG. 10 is a front view of another layer of microlens array in a two-layer microlens array structure;

FIG. 11 (a) is a schematic diagram of far field emergent light spots of a multilayer microlens array uniform light structure;

FIG. 11 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in FIG. 11 (a);

FIG. 12 is a side view of a two layer microlens array structure;

FIG. 13 is a front view of one layer of a microlens array in a two-layer microlens array structure;

FIG. 14 is an enlarged view of a portion of the microlens array shown in FIG. 13;

FIG. 15 is a front view of another layer of microlens array in a two-layer microlens array structure;

FIG. 16 (a) is a schematic diagram of far field emergent light spots of a multilayer microlens array uniform light structure;

FIG. 16 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in FIG. 16 (a);

FIG. 17 is a side view of a three layer microlens array structure;

FIG. 18 is a front view of a first layer of a microlens array in a three-layer microlens array structure;

FIG. 19 is an enlarged view of a portion of the microlens array shown in FIG. 18;

FIG. 20 is a front view of a second layer of microlens arrays in a three layer microlens array configuration;

FIG. 21 is a front view of a third layer of microlens array in a three layer microlens array configuration;

fig. 22 (a) is a schematic diagram of far-field emergent light spots of a three-layer microlens array uniform light structure;

fig. 22 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in fig. 22 (a).

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The gist of the present invention will be further described with reference to the accompanying drawings and examples.

Example 1

Referring to fig. 1, fig. 1 schematically shows a light uniformizing structure having two microlens arrays. The optical device comprises a substrate, a 100-double-layer microlens array dodging structure, a 110-first-layer dodging structure, a 111-base layer of the first-layer dodging structure, a 112-dodging layer of the first-layer dodging structure, and a 113-microlens array of the first-layer dodging structure; 120-a second layer of light homogenizing structure, 121-a base layer of the second layer of light homogenizing structure, 122-a light homogenizing layer of the second layer of light homogenizing structure, 123-a micro-lens array of the second layer of light homogenizing structure, and D represents a distance between the first layer of light homogenizing structure and the second layer of light homogenizing structure.

In an embodiment, a multilayer microlens array dodging structure according to the present invention may be a dodging structure having two layers of microlens arrays (a two-layer microlens array dodging structure), with reference to fig. 1, each layer of dodging structure includes a substrate layer, and a dodging layer formed on a surface of the substrate layer, a surface of the dodging layer facing away from the substrate layer is formed with the microlens array, and the microlens array forms a continuous surface on the surface of the dodging layer. In a specific application scenario, the microlens array 113 of the first light homogenizing structure and the microlens array 123 of the second light homogenizing structure both face the laser array light source, and light emitted from the laser array light source sequentially passes through the microlens array 113 of the first light homogenizing structure and the microlens array 123 of the second light homogenizing structure, and is diffused twice in total. By analogy, the arrangement mode of the multilayer microlens array dodging structure is also multilayer interval setting in proper order, so that light can pass through the multilayer microlens array in proper order to obtain multiple diffusion, and the light is more uniform without interference fringes.

In one embodiment, each layer of the microlens array is composed of a plurality of sub-lens arrangements, the optical surface types of the sub-lenses in the same layer of the microlens array are the same, and the optical surface types of the sub-lenses comprise even-order aspheric surfaces or deformed aspheric surface types.

In one embodiment, the microlens array of one layer and the substrate layer of the microlens array of another layer adjacent to the microlens array are arranged at intervals (in an actual implementation process, the microlens array of one layer and the microlens array of another layer can be connected in a mechanical connection manner to form a fixed interval), and the distance range of the interval arrangement is 0.1mm to 0.3mm. Referring to fig. 1, the light equalizing structure 100 in fig. 1 includes two microlens arrays, each microlens array is disposed on one side surface of the light equalizing layer, the microlens array 123 of the second light equalizing structure 120 is disposed opposite to the substrate layer 111 of the first light equalizing structure 110 to form a spacing layer (actually, it can be understood that an air layer, a vacuum layer, or a dielectric layer with a refractive index conforming to the practical application), and the thickness D of the spacing layer is 0.1mm to 0.3mm.

In one embodiment, each layer of the microlens array has a thickness in a range of 0.2mm to 0.5mm.

In an embodiment, with reference to fig. 1, the multilayer microlens array light uniformizing structure of the present invention includes two microlens arrays, one microlens array is composed of a plurality of even aspheric surface type sub-lenses arranged in a staggered manner, the curvature radius of the sub-lenses constituting the microlens array is in a range of 30 μm to 100 μm, and the cone coefficient is in a range of-1 to-1.2. The sub-lenses of the even-order aspheric surface type are arranged in a staggered manner, so that the sub-lenses are irregularly arranged, the boundary shape of each sub-lens is random, but a continuous surface can be formed after the sub-lenses are irregularly arranged, namely, the formed micro-lens array is continuous and uninterrupted. Of course, the irregular arrangement of the sub-lenses can also be obtained by random arrangement, or by first arranging the sub-lenses in an array and then randomly disordering the result of the array arrangement to form the irregular arrangement.

The microlens array on the other layer of the two-layer microlens array is formed by arranging a plurality of deformed aspheric surface type sub-lens arrays, the central distance range of any two adjacent sub-lenses is 25-45 mu m, the curvature radius range of the sub-lenses forming the deformed aspheric surface type of the microlens array in the transverse coordinate direction is 10-15 mu m, the curvature radius range in the longitudinal coordinate direction is 6-15 mu m, and the cone coefficient range of the sub-lenses is-1-1.2. The arrangement of the plurality of anamorphic aspheric surface type sub-lenses is actually an operation mode of arranging and combining a plurality of sub-lenses according to a specific sequence or rule, such as array arrangement in a matrix shape or a honeycomb shape.

The reference formula of the even-order aspheric surface type sub-lens is as follows:

wherein Z is the rise of the sub-lens, c is the curvature of the sub-lens, r is the radial coordinate of the sub-lens, K is the conic coefficient of the sub-lens, a ₁ -a ₈ The even aspheric coefficients of the even aspheric surfaces are expressed.

In one embodiment, one layer of the microlens array is composed of a plurality of even-order aspheric surface type sub-lenses which are arranged in a staggered manner, and the staggered arrangement can be arranged according to the following steps:

1. and (3) making array arrangement on the sub-lenses, recording the center distance between the adjacent sub-lenses as L, and fixing the center distance of each sub-lens, wherein making array arrangement on the sub-lenses is to arrange each sub-lens into a matrix. The method comprises the following steps of arranging a plurality of sub-lenses to form a micro-lens array arranged in a matrix.

2. And (3) randomly shifting the center of each sub-lens, wherein the value range of H is 0-0.1 × L, namely the shifting range is fixed, and the shifting direction is random. The method comprises the following steps of shifting each sub-lens in a micro-lens array arranged in a matrix to a random direction by a preset distance to form a micro-lens array arranged in a staggered mode.

3. And merging all the sub-lenses which are subjected to random offset, and removing the crossed parts among the sub-lenses, namely processing the microlens array which is arranged in a staggered mode to form a continuous surface, wherein the obtained microlens array has one or more continuous surfaces, and the shape of the sub-lenses which form the microlens array with the continuous surface is random, such as any polygon of quadrangle, pentagon, hexagon and the like.

In the step 2, the center of each sub-lens is randomly shifted by H, and the value range of H is 0 to 0.1 × l, so that the maximum ratio of the maximum value to the minimum value of the center distance between two adjacent sub-lenses in the microlens array arranged in a staggered manner is three-thirds. For example, if the center-to-center distance between two adjacent sub-lenses arranged in an array is L1, after the two sub-lenses are randomly shifted, the maximum value of the center-to-center distances between the two sub-lenses is 1.2 × L1 (that is, if the two sub-lenses are moved in opposite directions by 0.1 × L1, the distance between the two sub-lenses after being randomly shifted is 1.2 × L1); the minimum value of the center-to-center distances of the two sub-lenses is 0.8 × l1 (i.e. the two sub-lenses move toward each other by 0.1 × l1, then the distance after the two sub-lenses are randomly shifted is 0.8 × l 1), i.e. the ratio of the maximum value to the minimum value of the center-to-center distances of the two adjacent sub-lenses is not more than (1.2 × l 1)/(0.8 × l 1).

The microlens array on the other layer of the two-layer microlens array is formed by arranging a plurality of deformed aspheric surface type sub-lens arrays, and the reference formula of the deformed aspheric surface type sub-lens is as follows:

wherein Z is the rise of the sub-lens, cx is the curvature of the sub-lens in the X direction, cy is the curvature of the sub-lens in the y direction, A _2n And B _2n The aspheric coefficients of the deformed aspheric surfaces.

The light homogenizing structure described in this embodiment diffuses light emitted by the laser array light source through the two layers of microlens arrays, and destroys coherence of laser passing through the multilayer microlens array structure through superposition of diffusion effects, so that no interference fringes exist in light spots; under the condition that the curvature radius of the sub-lens is larger, the light emitted by the laser array light source passes through the two layers of micro-lens arrays to obtain a larger field angle, so that the TOF module can detect more areas; and no fault exists between the sub-lenses in each layer of micro-lens array, so that the sub-lenses are smooth and transitional, and the light transmittance and the embossing yield in the processing process are improved.

Example 2

In an embodiment, a multilayer microlens array dodging structure of the present invention may be a dodging structure having three microlens arrays, that is, similar to fig. 1, a three-layer microlens array is formed on the light dodging structure layer on the basis of fig. 1.

In one embodiment, in the three-layer microlens array, the first layer microlens array is composed of a plurality of even-order aspheric surface type sub-lenses which are arranged in a staggered mode, the curvature radius of the sub-lenses forming the layer microlens array ranges from 30 micrometers to 100 micrometers, and the cone coefficient ranges from-1 to-1.2; the micro lens array of the second layer is formed by arranging a plurality of even-order aspheric surface type sub lenses in a staggered manner, the curvature radius of the sub lenses forming the micro lens array of the second layer ranges from 20 micrometers to 40 micrometers, and the cone coefficient ranges from-1 to-1.2; the micro lens array of the third layer is formed by arranging a plurality of deformed aspheric surface type sub lens arrays, the central distance range of any two adjacent sub lenses is 25-45 mu m, the curvature radius range of the sub lenses forming the deformed aspheric surface type of the micro lens array is 10-20 mu m, and the cone coefficient range of the sub lenses is-1-1.2.

The first layer microlens array and the second layer microlens array are formed by arranging a plurality of even-order aspheric surface type sub lenses in a staggered manner, and the arrangement method of the staggered arrangement used can be the same as the arrangement method described in embodiment 1, and is not described herein again.

The dodging structure of the three-layer micro-lens array provided by the embodiment destroys coherence of laser passing through the multi-layer micro-lens array structure through superposition of multiple diffusion effects, so that no interference fringe exists in light spots, a larger field angle can be obtained, and a region detected by the TOF module is enlarged.

The embodiment of the present invention only provides an example of a two-layer microlens array light uniformizing structure and a three-layer microlens array light uniformizing structure, but the multilayer microlens array light uniformizing structure provided by the present invention is by no means limited to the single-layer and three-layer structures described in the embodiment, and a person skilled in the art can also obtain other technical solutions of the multilayer microlens array light uniformizing structure according to the technical solutions provided by the present invention, and the embodiments of the present invention are not illustrated in one example.

According to the multilayer microlens array dodging structure, the invention also provides a TOF lens which comprises the multilayer microlens array dodging structure, the multilayer microlens array dodging structure comprises at least two layers of microlens arrays, and an air layer with the thickness ranging from 0.1mm to 0.5mm is arranged between the microlens arrays close to the laser array light source and the laser array light source.

The invention also provides equipment provided with the TOF lens, which comprises the TOF lens, wherein the multilayer micro-lens array light homogenizing structure is arranged on the TOF lens.

Example 3:

an embodiment of the invention provides a multilayer microlens array dodging structure, and with reference to fig. 2 to 6, fig. 2 is a side view of a double-layer microlens array structure; FIG. 3 is a front view of one layer of a microlens array in a two-layer microlens array structure; FIG. 4 is an enlarged view of a portion of the microlens array shown in FIG. 3; FIG. 5 is a front view of another layer of microlens array in a two-layer microlens array structure; FIG. 6 (a) is a schematic diagram of far field emergent light spots of a multilayer microlens array uniform light structure; fig. 6 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in fig. 6 (a).

Wherein, 30-double-layer micro-lens array light homogenizing structure; 31-a first layer of microlens array; 32-a second layer of microlens array; 33-laser array light source.

In this embodiment, the double-layer microlens array light homogenizing structure of the present invention includes two layers of microlens arrays, which are a first layer microlens array 31 and a second layer microlens array 32, respectively, wherein an optical surface of the first layer microlens array 31 is an even-order aspheric surface, a curvature radius of a sub-lens constituting the first layer microlens array 31 is 100 μm, and a conic coefficient is-1.02; the optical surface of the second layer microlens array 32 is an anamorphic aspherical surface, the curvature radius of the sub-lenses forming the second layer microlens array 32 in the transverse direction is 14.2 μm, and the cone coefficient is-1.02; the radius of curvature in the longitudinal direction was 8.7 μm and the cone coefficient was-1.02.

The first layer microlens array 31 directly faces the laser array light source 33, and the distance from the laser array light source 33 is 0.1mm. The substrate layer to which the first layer microlens array 31 is attached and the second layer microlens array 32 are oppositely arranged to form a spacing layer, and the thickness of the spacing layer is 0.2mm.

Referring to fig. 6 (a) and 6 (b), after the laser array light source passes through the double-layer microlens array dodging structure described in this embodiment, the obtained diffused light spot is a rectangular ring-shaped light spot, the energy in the X direction reaches a peak value at a field angle of 65 degrees, the energy in the Y direction reaches a peak value at a field angle of 38 degrees, the energy in the X direction decreases to a half of the peak value at a field angle of 80 degrees, and the energy in the Y direction decreases to a half of the peak value at a field angle of 57 degrees (shown is a projected light spot at a distance of 250mm, the light spot linear quantity is converted into angular quantities, and then the gray scale ratio at each angular quantity is analyzed to obtain the energy peak information described in this embodiment).

In this embodiment, referring to fig. 4, in the double-layer microlens array dodging structure of this embodiment, a junction between two adjacent sub-lenses in each layer of microlens array has smooth transition, the junction has no cross section, and the filling rate is 100%.

Example 4:

an embodiment of the invention provides a multilayer microlens array dodging structure, and with reference to fig. 7 to 11, fig. 7 is a side view of a double-layer microlens array structure; FIG. 8 is a front view of one layer of a microlens array in a two-layer microlens array structure; FIG. 9 is an enlarged view of a portion of the microlens array shown in FIG. 8; FIG. 10 is a front view of another layer of microlens array in a two-layer microlens array structure; FIG. 11 (a) is a schematic diagram of far field emergent light spots of a multilayer microlens array uniform light structure; FIG. 11 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in FIG. 11 (a).

Wherein, 40-double-layer microlens array dodging structure; 41-a first layer of microlens array; 42-a second layer of microlens array; 43-laser array light source.

In this embodiment, the double-layer microlens array light homogenizing structure of the present invention includes two microlens arrays, namely a first microlens array 41 and a second microlens array 42, wherein the optical surface of the first microlens array 41 is an even aspheric surface, the curvature radius of the sub-lenses constituting the first microlens array 41 is 50 μm, and the conic coefficient is-1.1; the optical surface of the second layer microlens array 42 is an anamorphic aspherical surface, the curvature radius of the sub-lenses forming the second layer microlens array 42 in the transverse direction is 14 μm, and the conic coefficient is-1.02; the radius of curvature in the longitudinal direction was 8.7 μm and the cone coefficient was-1.02.

The first layer microlens array 41 directly faces the laser array light source 43, and is at a distance of 0.1mm from the laser array light source 43. The base layer to which the first layer microlens array 41 is attached and the second layer microlens array 42 are oppositely arranged to form a spacing layer, and the thickness of the spacing layer is 0.2mm.

Referring to fig. 11 (a) and 11 (b), after the laser array light source passes through the double-layer microlens array dodging structure described in this embodiment, the obtained diffused light spot is a rectangular ring-shaped light spot, the energy in the X direction reaches a peak value at an angle of view 64 degrees, the energy in the Y direction reaches a peak value at an angle of view 38 degrees, the energy in the X direction decreases to a half of the peak value at an angle of view 80 degrees, and the energy in the Y direction decreases to a half of the peak value at an angle of view 55 degrees.

In this embodiment, referring to fig. 9, in the double-layer microlens array dodging structure of this embodiment, a junction between two adjacent sub-lenses in each layer of microlens array has smooth transition, the junction has no cross section, and the filling rate is 100%.

Example 5:

an embodiment of the invention provides a multilayer microlens array dodging structure, and with reference to fig. 12 to 16, fig. 12 is a side view of a double-layer microlens array structure; FIG. 13 is a front view of one layer of a microlens array in a two-layer microlens array structure; FIG. 14 is an enlarged view of a portion of the microlens array shown in FIG. 13;

FIG. 15 is a front view of another layer of microlens array in a two-layer microlens array structure; FIG. 16 (a) is a schematic diagram of far-field emergent light spots of a multi-layer microlens array uniform light structure; fig. 16 (b) is a gray scale energy scale diagram corresponding to the light spot diagram shown in fig. 16 (a).

Wherein, 50-double-layer micro-lens array light homogenizing structure; 51-a first layer microlens array; 52-a second layer of microlens array; 53-laser array light source.

In this embodiment, the double-layer microlens array dodging structure of the present invention includes two microlens arrays, namely a first microlens array 51 and a second microlens array 52, wherein the optical surface of the first microlens array 51 is a spherical surface, and the radius of curvature of the sub-lenses constituting the first microlens array 51 is 33 μm; the optical surface of the second-layer microlens array 52 is a deformed aspheric surface, the curvature radius of the sub-lenses forming the second-layer microlens array 52 in the transverse direction is 14 μm, and the conic coefficient is-1.02; the radius of curvature in the longitudinal direction was 8.7 μm and the cone coefficient was-1.02.

The first layer microlens array 51 directly faces the laser array light source 53, and the distance from the laser array light source 53 is 0.1mm. The substrate layer to which the first layer microlens array 51 is attached and the second layer microlens array 52 are oppositely arranged to form a spacing layer, and the thickness of the spacing layer is 0.2mm.

Referring to fig. 16 (a) and 16 (b), when the laser array light source passes through the double-layer microlens array dodging structure described in this embodiment, the obtained diffused light spot is a rectangular ring-shaped light spot, the energy in the X direction reaches a peak value at a 59-degree angle of view, the energy in the Y direction reaches a peak value at a 35-degree angle of view, the energy in the X direction decreases to a half of the peak value at a 82-degree angle of view, and the energy in the Y direction decreases to a half of the peak value at a 60-degree angle of view.

In this embodiment, referring to fig. 14, in the double-layer microlens array dodging structure described in this embodiment, a junction between two adjacent sub-lenses in each layer of microlens array is smooth in transition, the junction has no cross section, and the filling rate is 100%.

Example 6:

an embodiment of the invention provides a multi-layer microlens array dodging structure, which is combined with fig. 17 to 22, and fig. 17 is a side view of a three-layer microlens array structure; FIG. 18 is a front view of a first layer of a microlens array in a three layer microlens array structure; FIG. 19 is an enlarged view of a portion of the microlens array shown in FIG. 18; FIG. 20 is a front view of a second layer of microlens arrays in a three layer microlens array configuration; FIG. 21 is a front view of a third layer of microlens array in a three layer microlens array structure; fig. 22 (a) is a schematic diagram of far-field emergent light spots of a three-layer microlens array uniform light structure; fig. 22 (b) is a gray scale energy ratio diagram corresponding to the light spot diagram shown in fig. 22 (a).

Wherein, 60-double-layer microlens array dodging structure; 61-a first layer of microlens array; 62-a second layer of microlens array; 63-a third layer of microlens array; 64-laser array light source.

In this embodiment, the three-layer microlens array light homogenizing structure of the present invention includes three layers of microlens arrays, which are a first layer microlens array 61, a second layer microlens array 62 and a third layer microlens array 63, respectively, optical surface types of the first layer microlens array 61 and the second layer microlens array 62 are both even-order aspheric surface types, a curvature radius of a sub-lens constituting the first layer microlens array 61 is 50 μm, and a conic coefficient is-1.02; the radius of curvature of the sub-lenses constituting the second-layer microlens array 62 is 25 μm, and the conic coefficient is-1; the optical surface of the third microlens array 63 is an anamorphic aspherical surface, the curvature radius of the sub-lenses forming the third microlens array 63 in the transverse direction is 16 μm, and the conic coefficient is-0.98; the radius of curvature in the longitudinal direction was 12.5 μm and the cone coefficient was-0.98.

The first layer of microlens array 61 directly faces the laser array light source 64, and is at a distance of 0.1mm from the laser array light source 64. The base layer to which the first layer microlens array 61 is attached and the second layer microlens array 62 are oppositely arranged to form a spacer layer, and the thickness of the spacer layer is 0.2mm.

Referring to fig. 22 (a) and 22 (b), when the laser array light source passes through the three-layer microlens array dodging structure described in this embodiment, the obtained diffused light spot is a rectangular ring-shaped light spot, the energy in the X direction reaches a peak value at a field angle of 50 degrees, the energy in the Y direction reaches a peak value at a field angle of 42 degrees, the energy in the X direction decreases to a half of the peak value at a field angle of 67 degrees, and the energy in the Y direction decreases to a half of the peak value at a field angle of 52 degrees.

If the single-layer microlens array is to have the same angle of view as the multi-layer microlens array, the radius of curvature and the aperture of the sub-lenses in the single-layer microlens array are larger than those of the sub-lenses in the multi-layer microlens array. The larger the curvature radius and the caliber in the actual processing process, the higher the processing difficulty of the sub-lens, and the higher the stamping difficulty. Therefore, the multilayer microlens array dodging structure can reduce the processing difficulty on the basis of meeting the optical effect and the field angle.

In this embodiment, referring to fig. 19, in the three-layer microlens array dodging structure described in this embodiment, the junction between two adjacent sub-lenses in each layer of microlens array has smooth transition, the junction has no cross section, and the filling rate is 100%.

In summary, compared with the prior art, the multilayer microlens array dodging structure provided by the invention has the advantages that the microlens arrays of all layers are closely arranged, the curvature radius of each layer of sub-lens of the multilayer microlens is larger, the rise is lower, the processing is easy, and the processing difficulty and errors are reduced.

In one embodiment, the sub-lenses can be arranged irregularly at the first layer or the second layer of the multi-layer micro-lens array, so that the coherence of the light rays of the laser array after passing through the micro-lens array is destroyed, and the interference fringes of the light spots are eliminated.

Furthermore, the multilayer micro-lens array structure can enable the light emitted by the laser array to obtain a larger field angle after passing through the multilayer micro-lens array under the condition that the radius of curvature of the sub-lens is larger, so that the TOF module can detect more areas; and no fault exists between the sub-lenses in each layer of micro-lens array, so that the sub-lenses are smooth and transitional, and the light transmittance and the imprinting yield in the processing process are improved.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.

Claims (15)

1. A multilayer micro-lens array dodging structure is characterized by comprising at least two layers of micro-lens arrays, each layer of micro-lens array is composed of a plurality of sub-lenses in an arrangement manner,

the optical surface types of a plurality of sub lenses forming the micro lens array on the same layer are the same.

2. The light unifying structure of multilayer microlens array as claimed in claim 1,

and the sub-lenses are arranged in a staggered manner to form a layer of micro-lens array, and in the micro-lens array, the ratio of the maximum value to the minimum value of the center distance between every two adjacent sub-lenses is not more than three-half.

3. The dodging structure of a multi-layer micro-lens array as recited in claim 1,

at least one layer of the micro lens array is composed of a plurality of even-order aspheric surface type sub lenses, and the sub lenses are arranged in a staggered mode to form the micro lens array.

4. The light unifying structure of multilayer microlens array as claimed in claim 3,

the curvature radius of the sub-lenses of a plurality of even-order aspheric surface types forming the micro-lens array ranges from 30 micrometers to 100 micrometers, and the cone coefficient ranges from-1 to-1.2.

5. The multilayer microlens array dodging structure according to claim 3, wherein the curvature radius of the sub-lenses of the even-order aspheric surface type constituting the microlens array ranges from 20 μm to 40 μm, and the conic coefficient ranges from-1 to-1.2.

6. The light unifying structure of multilayer microlens array as claimed in claim 1,

at least one layer of the micro lens array is composed of a plurality of deformed aspheric surface type sub lenses, and the sub lens arrays are arranged to form the micro lens array.

7. The multilayer microlens array dodging structure according to claim 6, wherein the sub-lenses of the anamorphic aspherical surface type constituting said microlens array have a radius of curvature in a first coordinate direction ranging from 10 μm to 15 μm and a radius of curvature in a second coordinate direction ranging from 6 μm to 15 μm,

the cone coefficients of a plurality of the sub-lenses are in the range of-1 to-1.2,

the center-to-center distance between any two adjacent sub-lenses is in the range of 25-45 μm.

8. The multilayer microlens array dodging structure according to claim 6, wherein the curvature radius of the sub-lenses of the anamorphic aspherical surface type constituting the microlens array is in a range of 10 μm to 20 μm,

the cone coefficients of a plurality of the sub-lenses range from-1 to-1.2,

the center-to-center distance between any two adjacent sub-lenses is in the range of 25-45 μm.

9. The multi-layer micro-lens array light-homogenizing structure according to claim 1, characterized in that the multi-layer micro-lens array light-homogenizing structure comprises two layers of micro-lens arrays, one layer of micro-lens array is composed of a plurality of even-order aspheric surface type sub-lenses which are arranged in a staggered manner, the curvature radius of the plurality of sub-lenses composing the layer of micro-lens array ranges from 30 μm to 100 μm, and the cone coefficient ranges from-1 to-1.2;

the micro lens array of the other layer is formed by arranging a plurality of deformed aspheric surface type sub lens arrays, the central distance between any two adjacent sub lenses ranges from 25 micrometers to 45 micrometers, the curvature radius of the sub lenses forming the deformed aspheric surface type of the micro lens array in the transverse coordinate direction ranges from 10 micrometers to 15 micrometers, the curvature radius of the sub lenses forming the deformed aspheric surface type of the micro lens array in the longitudinal coordinate direction ranges from 6 micrometers to 15 micrometers, and the cone coefficients of the sub lenses range from-1 to-1.2.

10. The multi-layer micro-lens array light-homogenizing structure according to claim 1, characterized in that the multi-layer micro-lens array light-homogenizing structure comprises three layers of micro-lens arrays, the micro-lens array of the first layer is composed of a plurality of sub-lenses of even-order aspheric surface type which are arranged in a staggered manner, the curvature radius of the plurality of sub-lenses composing the micro-lens array of the layer is in the range of 30 μm to 100 μm, and the cone coefficient is in the range of-1 to-1.2;

the second layer of the micro lens array is formed by arranging a plurality of even-order aspheric surface type sub lenses in a staggered manner, the curvature radius of the sub lenses forming the micro lens array is 20-40 mu m, and the cone coefficient is-1-1.2;

the micro lens array of the third layer is formed by arranging a plurality of deformed aspheric surface type sub lens arrays, the central distance range of any two adjacent sub lenses is 25-45 mu m, the curvature radius range of the sub lenses forming the deformed aspheric surface type of the micro lens array is 10-20 mu m, and the cone coefficient range of the sub lenses is-1-1.2.

11. The multilayer microlens array dodging structure according to claim 1, further comprising a substrate layer, and a dodging layer formed on the surface of the substrate layer, wherein the surface of the dodging layer, which faces away from the substrate layer, is formed with the microlens array;

the micro lens array forms a continuous surface on the surface of the light homogenizing layer;

the micro lens array on one layer and the substrate layer of the micro lens array on the other layer adjacent to the micro lens array are oppositely arranged at intervals, and the distance range between the micro lens array and the substrate layer of the micro lens array on the other layer adjacent to the micro lens array is 0.1 mm-0.3 mm;

the optical surface shapes of the sub-lenses constituting the microlens array include aspherical surface shapes;

the thickness range of each layer of the micro lens array is 0.2 mm-0.5 mm.

12. A design method of a multilayer micro-lens array dodging structure is characterized by comprising the following steps:

arranging a plurality of sub-lens arrays, and determining the center distance between any two adjacent sub-lenses according to expected light spots;

and taking the central point of each sub-lens as an initial point to shift a preset distance on the plane where the sub-lens is located, and removing the crossed part of two adjacent sub-lenses to obtain the micro-lens array.

13. The design method of the dodging structure with multiple layers of micro-lens arrays as claimed in claim 12, wherein the center-to-center distance between any two adjacent sub-lenses is in the range of 25 μm to 45 μm;

shifting each sub-lens by a preset distance on a plane on which the sub-lens is positioned with the central point of the sub-lens as an initial point, wherein the maximum value of the preset distance for shifting each sub-lens is 0.1 times of the central distance between the sub-lens at the initial point and the sub-lens adjacent to the sub-lens,

the minimum value of the preset distance by which each sub-lens is shifted is 0.

14. A TOF lens, which comprises the multilayer microlens array dodging structure as claimed in any one of claims 1 to 11, wherein the multilayer microlens array dodging structure comprises at least two layers of microlens arrays, and an air layer with a thickness ranging from 0.1mm to 0.5mm is arranged between the microlens array close to a laser array light source and the laser array light source.

15. A device equipped with a TOF lens, comprising the TOF lens according to claim 14, on which the multilayer microlens array dodging structure according to any one of claims 1 to 11 is mounted.

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