CN216718826U

CN216718826U - Light-emitting module and TOF imaging device

Info

Publication number: CN216718826U
Application number: CN202220210643.9U
Authority: CN
Inventors: 徐越; 周振; 杨明; 赵永花
Original assignee: Suzhou University; SVG Tech Group Co Ltd
Current assignee: Suzhou University; SVG Tech Group Co Ltd
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2022-06-10
Anticipated expiration: 2032-01-26

Abstract

The application relates to a light-emitting module and a TOF imaging device, wherein the light-emitting module comprises a light source for emitting a light beam, a first lens with negative focal power and a second lens with positive focal power, the first lens and the second lens are arranged at intervals, and the light source and the second lens are oppositely arranged on two sides of the first lens; the light beam is diffused by the first lens and then emitted to the second lens to be converged, so that the irradiation distance of the light beam is prolonged, the caliber of the light beam at the position of the light outlet hole is reduced, the size of the light outlet module is reduced, a larger divergence angle is achieved by a smaller volume, the requirement of miniaturization of the existing electronic equipment is met, meanwhile, the energy loss of the light beam is reduced, and the detection distance and the imaging quality of the TOF imaging device are improved. The surface types of the first lens and the second lens are deformed aspheric surfaces, light source images of the array laser light source can be eliminated and the obtained light field distribution can be adjusted by adjusting the parameters of the first lens and the second lens, and meanwhile, the size of the light outlet hole is changed, and a larger field angle is obtained.

Description

Light-emitting module and TOF imaging device

Technical Field

The utility model relates to a light emitting module and a TOF imaging device, and belongs to the field of three-dimensional sensing.

Background

TOF (Time of flight) techniques can perform three-dimensional sensing and distance measurement. Among them, the ITOF (indirect time of flight) technique obtains depth information of different points of an object by measuring a phase offset.

The ITOF comprises a light emitting module and a receiving module, wherein the light emitting module emits specific light field information with a large view field, the receiving module receives the light field information reflected from an object to be detected, and the depth information of each point of the object to be detected is calculated through a phase difference algorithm.

At present, electronic devices are gradually miniaturized, and the ITOF applied thereto is required to be further miniaturized. The conventional ITOF needs a light outlet to emit light, but the aperture of the light outlet is large, and more than 5mm is needed to enable all light to be emitted from the light outlet, and if the aperture is less than 5mm, a large amount of reflected stray light is brought. If the requirement that the aperture of the light outlet is small is met, the field angle is greatly reduced, and the range of depth information perceived by the ITOF is reduced. ITOF cannot be dimensioned to meet the requirements.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a light-emitting module which has small volume, smaller light-emitting aperture and larger divergence angle and meets the requirement of miniaturization of the current electronic equipment.

In order to achieve the purpose, the utility model provides the following technical scheme: the utility model provides a light-emitting module, is adapted to TOF imaging device, the light-emitting module includes:

a light source for emitting a light beam;

a first lens having a negative focal power;

a second lens having a positive refractive power;

the first lens and the second lens are arranged at intervals, the light source and the second lens are oppositely arranged on two sides of the first lens, the light beam is diffused by the first lens and then is emitted to the second lens, the first lens is provided with a first lens surface close to the light source and a second lens surface far away from the light source, and the second lens is provided with a third lens surface close to the light source and a fourth lens surface far away from the light source;

the first lens and the second lens are anamorphic aspheric surfaces, the radius of curvature of the first lens surface is larger than that of the second lens surface in the same direction, and the radius of curvature of the third lens surface is larger than that of the second lens surface in the same direction.

Further, the first lens is a plano-concave lens or a biconcave lens, the curvature radius of the first lens surface in the X direction is 1 mm-50 mm, and the cone coefficient is-8-1; the curvature radius of the first lens surface in the Y direction is 1 mm-50 mm, and the cone coefficient is-8-1; the curvature radius of the second lens surface in the X direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the second lens surface in the Y direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1.

Furthermore, the second lens is a biconvex lens, the curvature radius of the third lens surface in the X direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the third lens surface in the Y direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the fourth lens surface in the X direction is 0.05 mm-0.8 mm, and the coefficient of the cone is-5-1; the curvature radius of the fourth lens surface in the Y direction is 0.05 mm-0.8 mm, and the cone coefficient is-5-1.

Further, the refractive index of the first lens is 1.5-1.8; the refractive index of the second lens is 1.5-1.8; the thickness of the first lens is 0-0.1 mm, and the optical diameter is 0-2 mm; the thickness of the second lens is 0-2 mm, and the optical diameter is 0-2.5 mm; the distance between the light source and one side of the first lens, which is close to the light source, is 0.05 mm-0.8 mm; the distance between one side of the first lens, which is far away from the light source, and one side of the second lens, which is close to the light source, is 0.4-1 mm.

Further, a micro-lens array is arranged between the light source and the first lens.

Further, the micro lens array comprises a plurality of micro lenses, and the surface of each micro lens is an anamorphic aspheric surface.

Furthermore, the curvature radius of the micro lens in the X direction is 10-300 mu m, and the cone coefficient is-0.95-8; the curvature radius of the micro lens in the Y direction is 10-300 mu m, and the cone coefficient is-0.95-8.

Furthermore, the refractive index of the micro lens array is 1.5-1.8, and the distance between the light source and the side, close to the light source, of the micro lens array is 0.05-0.2 mm; the distance between one side of the micro lens array, which is far away from the light source, and one side of the first lens, which is close to the light source, is 0.1-0.5 mm.

The utility model also provides a TOF imaging device which comprises the light-emitting module.

The utility model has the beneficial effects that: the light emitting module comprises a first lens for diffusing light beams and a second lens for converging the light beams, wherein the light beams are converged after being diffused, so that the irradiation distance of the light beams is prolonged, the aperture of the light beams at the position of a light outlet hole is reduced, the size of the light emitting module is reduced, a larger divergence angle is achieved with a smaller size, the requirement of miniaturization of the conventional electronic equipment is met, the energy loss of the light beams is reduced, the definition is improved, and the detection distance and the imaging quality of a TOF imaging device are improved.

In addition, the surface types of the first lens and the second lens are deformed aspheric surfaces, the obtained light field distribution can be adjusted by adjusting parameters of the first lens and the second lens, the light source image of the array laser light source can be eliminated, the obtained light field distribution can be adjusted, the light uniformizing effect is achieved, the light spot energy distribution can be changed by changing the surface type parameters of the first lens and the second lens, and meanwhile, the size of the light outlet is changed, and a larger field angle is obtained.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Drawings

Fig. 1 is a schematic structural diagram of a light emitting module according to a first embodiment of the present invention;

FIG. 2 is a schematic view of the surface structure of the microlens array shown in FIG. 1;

FIG. 3 is a beam path diagram of the light exiting module shown in FIG. 1;

fig. 4 is a schematic diagram of an emergent light field distribution of the light-emitting module shown in fig. 1, wherein fig. 4(a) is a schematic diagram of an emergent light spot of the light-emitting module; FIG. 4(b) is a schematic diagram of the energy scale at a vertical field angle with respect to a zero degree field angle; FIG. 4(c) is a schematic diagram of the energy ratio at a horizontal field angle with respect to a zero degree field angle;

FIG. 5 is a schematic view of the light exit aperture 1mm away from the light source side of the second lens in FIG. 1;

fig. 6 is a schematic structural diagram of a light emitting module according to a second embodiment of the present invention;

FIG. 7 is a schematic view of the surface structure of the microlens array shown in FIG. 6;

FIG. 8 is a beam path diagram of the light exiting module shown in FIG. 6;

fig. 9 is a schematic diagram of the distribution of the emergent light field of the light-emitting module shown in fig. 6, wherein fig. 9(a) is a schematic diagram of an emergent light spot of the light-emitting module; FIG. 9(b) is a schematic diagram of the energy scale at a vertical field angle with respect to a zero degree field angle; FIG. 9(c) is a schematic diagram of the energy ratio at a horizontal field angle with respect to a zero degree field angle;

FIG. 10 is a schematic view of the light exit aperture 1mm from the side of the second lens away from the light source in FIG. 6;

fig. 11 is a schematic structural diagram of a light emitting module according to a third embodiment of the present invention;

FIG. 12 is a beam path diagram of the light exiting module shown in FIG. 11;

fig. 13 is a schematic diagram of the distribution of the emergent light field of the light-emitting module shown in fig. 11, wherein fig. 13(a) is a schematic diagram of the emergent light spot of the light-emitting module; FIG. 13(b) is a schematic diagram of the energy scale at a vertical field angle with respect to a zero degree field angle; FIG. 13(c) is a schematic diagram of the energy ratio at a horizontal field angle with respect to a zero degree field angle;

FIG. 14 is a schematic view of the light exit aperture 1mm from the side of the second lens away from the light source in FIG. 11;

fig. 15 is a schematic structural diagram of a light emitting module according to a third embodiment of the present invention;

FIG. 16 is a beam path diagram of the light exit module shown in FIG. 15;

fig. 17 is a schematic diagram of the distribution of the emergent light field of the light-emitting module shown in fig. 15, wherein fig. 17(a) is a schematic diagram of the emergent light spots of the light-emitting module; FIG. 17(b) is a schematic diagram of the energy scale at a vertical field angle with respect to a zero degree field angle; FIG. 17(c) is a schematic diagram of the energy scale at a horizontal field angle with respect to a zero degree field angle;

fig. 18 is a schematic view of the light exit aperture at a position 1mm away from the light source side of the second lens in fig. 15.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. 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.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the mechanism or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the present application provides a light-emitting module 100 adapted to a TOF imaging apparatus, where the light-emitting module 100 includes a light source 1 for emitting a light beam, a first lens 2 having a negative refractive power, and a second lens 3 having a positive refractive power.

The first lens 2 and the second lens 3 are arranged at intervals, and the light source 1 and the second lens 3 are oppositely arranged at two sides of the first lens 2. That is, the light source 1, the first lens 2 and the second lens 3 are sequentially arranged, the first lens 2 and the second lens 3 are both located on an extending path of the light beam, the light beam is diffused by the first lens 2 and then emitted to the second lens 3, the second lens 3 converges the light beam, and then the light beam is emitted through a light emitting hole (not shown). The light beam is shot to second lens 3 after 2 diffusion of first lens, the clear aperture of second lens 3 has been increased for the focus of second lens 3 becomes long, the irradiation distance of extension light beam, thereby make the aperture of the light beam in light-emitting hole position department reduce, with the size that reduces the light-emitting hole, reduce the size of light-emitting module 100, reduce the energy loss of light beam simultaneously, reach great divergence angle, improve the definition, improve TOF imaging device's detection distance and image quality.

It should be noted that, for the light-emitting module 100, the distance between the light source 1 and the light-emitting hole is fixed, and is generally 4mm, and the distance between the side of the second lens 3 away from the light source 1 and the light-emitting hole is also fixed, and is generally 1 mm. Wherein the light exit hole is formed on the receptacle 4 shown in fig. 3.

In order to reduce the size of the light-emitting module 100, the size of the light beam at the light-emitting hole needs to be reduced, so that all light can be emitted from the light-emitting hole with a smaller light-emitting aperture, and stray light emission is avoided. And then detecting the size of the light beam at a position 1mm away from the light source 1 side from the second lens 3.

The light beam emitted from the light source 1 may be visible light or invisible light such as infrared light, ultraviolet light, or the like. In this embodiment, in order to reduce the volume of the light exiting module 100, the light source 1 is preferably a laser generator array.

The first lens 2 is a plano-concave lens (not shown) having a negative power or a biconcave lens having a negative power. The second lens 3 is a double-convex lens having a positive optical power. The first lens 2 and the second lens 3 have the functions of shaping and dodging the light beams and are used for forming light spots with specific light field distribution.

The first lens 2 and the second lens 3 have anamorphic aspherical surfaces.

The first lens 2 has a first lens surface 21 disposed close to the light source 1 and a second lens surface 22 disposed far from the light source 1, and both the first lens surface 21 and the second lens surface 22 are anamorphic aspherical surfaces.

When the first lens 2 is a plano-concave lens having negative refractive power, one of the first lens surface 21 and the second lens surface 22 is a flat surface, and the other of the first lens surface 21 and the second lens surface 22 is a concave surface. That is, the flat surface may be disposed near the light source 1, or the concave surface may be disposed near the light source 1, which is not particularly limited herein.

The second lens 3 has a third lens surface 31 disposed close to the light source 1 and a fourth lens surface 32 disposed far from the light source 1, and both the third lens surface 31 and the fourth lens surface 32 are anamorphic aspherical surfaces.

The deformed aspheric surface satisfies the formula:

wherein Z is the rise of the lens, C_xIs the curvature of the lens in the X direction, C_yIs the curvature of the lens in the y-direction, A_2nAnd B_2nThe aspheric coefficients of the deformed aspheric surfaces.

The curvature radius of the first lens surface 21 in the X direction is 1 mm-50 mm, and the cone coefficient is-8-1; the curvature radius of the first lens surface 21 in the Y direction is 1 mm-50 mm, and the cone coefficient is-8-1; the curvature radius of the second lens surface 22 in the X direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the second lens surface 22 in the Y direction is 0.1 mm-1 mm, the conic coefficient is-5-1, wherein the curvature radius of the first lens surface is larger than that of the second lens surface in the same direction.

The curvature radius of the third lens surface 31 in the X direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the third lens surface 31 in the Y direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the fourth lens surface 32 in the X direction is 0.05 mm-0.8 mm, and the conic coefficient is-5-1; the curvature radius of the fourth lens surface 32 in the Y direction is 0.05mm to 0.8mm, and the conic coefficient is-5 to 1. The curvature radius of the third lens surface is larger than that of the second lens surface in the same direction.

It should be noted that the "X direction" mentioned herein is not to be understood as a limitation to the present invention, and those skilled in the art may also understand or consider this as a corresponding "Y direction" in practical application. In this embodiment, the X direction is the lateral direction of the lens, and the Y direction is the longitudinal direction of the lens.

The refractive index of the first lens 2 is 1.5-1.8; the refractive index of the second lens 3 is 1.5-1.8; the thickness of the first lens 2 is 0-0.1 mm, and the optical diameter is 0-2 mm; the thickness of the second lens 3 is 0-2 mm, and the optical diameter is 0-2.5 mm; the distance between the light source 1 and one side of the first lens 2 close to the light source 1 is 0.05 mm-0.8 mm; the distance between the side of the first lens 2 far away from the light source 1 and the side of the second lens 3 close to the light source 1 is 0.4 mm-1 mm.

The first lens 2 and the second lens 3 can be manufactured in batches by optical glass lens compression molding technology, the compression molding technology is that softened glass is put into a high-precision mold, and the optical lens meeting the use requirement is directly molded by compression at one time under the conditions of heating and pressurizing and no oxygen.

The laser array emitted by the array of laser generators forms a desired light field pattern, and the resulting light field distribution can be adjusted by adjusting the parameters of the first lens 2 and the second lens 3.

The whole dodging lens group can eliminate the light source image of the array laser light source 1, thereby achieving the dodging effect.

In another embodiment, a micro lens array 5 is further disposed between the light source 1 and the first lens 2.

The micro lens array 5 is located on the extending path of the light beam, and the light beam firstly irradiates the micro lens array 5 and then passes through the first lens 2 and the second lens 3 in sequence. The micro lens array 5 plays a role in light uniformizing, interference fringes possibly brought by a laser array are eliminated, light beams are shaped by the first lens 2 and the second lens 3 to form light spots distributed in a specific square, and the quality of the light beams emitted by the light emitting module 100 is improved.

The microlens array 5 is formed on a substrate, which may be made of glass or the like, for example, a substrate made of a polymer material or the like. It should be noted that the microlens array 5 may be located on a side of the substrate close to the light source 1, or may be located on a side of the substrate away from the light source 1, and is not limited in this respect.

The microlens array 5 may be a concave microlens array 5 or a convex microlens array 5.

The micro lens array 5 comprises a plurality of micro lenses, and the surface types of the micro lenses are all deformed aspheric surfaces. Also, the anamorphic aspherical surface satisfies the above formula. Wherein Z is the rise of the microlens, C_xIs the curvature of the microlens in the X direction, C_yIs the curvature of the microlens in the y-direction, A_2nAnd B_2nThe aspheric coefficients of the deformed aspheric surfaces. The curvature radius of the micro lens in the X direction is 10-300 μm, and the micro lens is conicalThe coefficient is-0.95 to-8; the curvature radius of the micro lens in the Y direction is 10-300 mu m, and the cone coefficient is-0.95-8.

The shape of the micro-lens can be triangle, quadrangle, pentagon, hexagon, etc.

The method comprises the following steps of arranging a plurality of microlenses into an array at intervals, wherein the positions of the microlenses follow a random arrangement rule, specifically, firstly, arranging the microlenses in the array mode, enabling the distance between the central points of the adjacent microlenses to be L after the array arrangement is carried out, enabling the microlenses to respectively carry out X-L displacement on an X axis and a Y axis by taking the central points after the array arrangement as initial points, wherein X is a random number from-Y to + Y, carrying out merging treatment after the random arrangement of the microlenses is carried out, obtaining a randomly arranged microlens array 5, improving the light beam homogenizing performance of the microlens array, eliminating the interference phenomenon after a laser array passes through a lens array group, and keeping good uniformity of a light field.

The distance between the center points of two adjacent microlenses is determined by the curvature radius selected by the two corresponding microlenses and the required formed light spot shape, the larger the curvature radius is, the larger the distance between the center of the microlens and the center of the microlens is, the longer the length of the light spot shape in the direction of the connecting line of the centers of the two adjacent microlenses is, and if the curvature radius is determined and the length of the light spot shape in the direction of the connecting line of the centers of the two adjacent microlenses is required to be longer, the larger the distance between the center of the microlens and the center of the microlens is.

The preparation method of the micro lens array 5 comprises the steps of firstly preparing a micro lens array mother plate, preparing a micro lens array replica according to the micro lens array mother plate, and preparing the micro lens array 5 according to the micro lens array replica.

Specifically, a microlens array master mask is processed by a photoetching method, a photosensitive material layer is attached to a glass substrate, a template is manufactured by adding different exposure quantities to different positions of the photosensitive material layer, the exposure depth which can be reached by different laser energies is controlled by a layered photoetching method according to a given structure, and the composite microlens array master mask with a good surface structure is manufactured. The micro-lens array replica plate is manufactured in batch by a nano-imprinting method. The method for manufacturing the microlens array 5 is the prior art, and detailed description thereof is omitted.

The refractive index of the micro lens array 5 is 1.5-1.8, and the distance between the light source 1 and one side of the micro lens array 5 close to the light source 1 is 0.05-0.2 mm; the distance between one side of the micro lens array 5, which is far away from the light source 1, and one side of the first lens 2, which is close to the light source 1, is 0.1 mm-0.5 mm.

The light-emitting module 100 is described in detail with reference to the following embodiments.

Example one

Referring to fig. 1 to 5, the light-emitting module 100 in the present embodiment includes a light source 1, a micro lens array 5, a first lens 2 and a second lens 3.

The refractive index of the microlens array 5, the refractive index of the first lens 2, and the refractive index of the second lens 3 are all 1.52. The first lens 2 is a biconcave lens and the second lens 3 is a biconvex lens. The micro lens array 5 is positioned on one side of the substrate close to the light source 1, and the distance between the light source 1 and one side of the micro lens array 5 close to the light source 1 is 0.05 mm; the distance between the side of the micro lens array 5 far away from the light source 1 and the side of the first lens 2 close to the light source 1 is 0.25mm, and the distance between the side of the first lens 2 far away from the light source 1 and the side of the second lens 3 close to the light source 1 is 0.5 mm.

The first lens 2 is 0.1mm thick and 2mm in optical diameter, and the second lens 3 is 2mm thick and 2.5mm in optical diameter.

The initial pitch of adjacent microlenses of the microlens array 5 is 10 μm. The optical surface of the micro lens is an anamorphic aspheric surface. The curvature radius of the micro lens in the X direction is 200 mu m, and the cone coefficient is-1.5; the curvature radius of the microlens in the Y direction was 200 μm, and the conic coefficient was-1.5. The surface structure of the resulting microlens array 5 is schematically shown in fig. 2.

Both the first lens surface 21 and the second lens surface 22 of the first lens 2 are anamorphic aspherical surfaces. The curvature radius of the first lens surface 21 in the X direction is 10mm, and the conic coefficient is-2; the curvature radius of the first lens surface 21 in the Y direction is 10mm, and the conic coefficient is-2; the curvature radius of the second lens surface 22 in the X direction is 0.5mm, and the conic coefficient is-2.5; the second lens surface 22 has a radius of curvature of 0.357mm in the Y direction and a conic coefficient of-2.5.

The third lens surface 31 and the fourth lens surface 32 of the second lens 3 are both anamorphic aspherical surfaces. The curvature radius of the third lens surface 31 in the X direction is 0.5714mm, and the conic coefficient is-2; the curvature radius of the third lens surface 31 in the Y direction is 0.5263mm, and the conic coefficient is-2; the curvature radius of the fourth lens surface 32 in the X direction is 0.2326mm, and the conic coefficient is-2.5; the radius of curvature of the fourth lens surface 32 in the Y direction is 0.2857mm, and the conic coefficient is-2.5.

In this embodiment, referring to fig. 3, after being homogenized by the micro lens array 5, the light beam emitted by the light source 1 is diverged by the first lens 2, and then converged by the second lens 3 to form a light spot. Referring to fig. 4, fig. 4(a) shows a light spot 250nm away from the light source 1 from the second lens 3, where the light spot is h/L according to tan (θ/2), where h is a half height of the light spot, and L is a position away from the light uniformizing structure. The X direction of the light spot reaches a peak value at 54 degrees, the peak value energy is 114% of the central energy, the Y direction reaches a peak value at 48 degrees, the peak value energy is 114% of the central energy, the energy of the X direction is reduced to 80% of the central energy at 70 degrees, and the field angle is 80 degrees when the energy is reduced to 0; the energy in the Y direction is reduced to 80% of the central energy at 56 degrees, and the field angle is 78 ° when the energy is reduced to 0.

Referring to fig. 5, the light exit aperture 1mm away from the side of the second lens 3 away from the light source 1 is 1.16 mm.

Example two

Referring to fig. 6 to 10, the light-emitting module 100 in the present embodiment includes a light source 1, a micro lens array 5, a first lens 2 and a second lens 3.

The refractive index of the microlens array 5, the refractive index of the first lens 2, and the refractive index of the second lens 3 are all 1.52. The first lens 2 is a biconcave lens and the second lens 3 is a biconvex lens. The micro lens array 5 is positioned on one side of the substrate far away from the light source 1, and the distance between the light source 1 and one side of the micro lens array 5 close to the light source 1 is 0.05 mm; the distance between the side of the micro lens array 5 far away from the light source 1 and the side of the first lens 2 close to the light source 1 is 0.25mm, and the distance between the side of the first lens 2 far away from the light source 1 and the side of the second lens 3 close to the light source 1 is 0.5 mm.

The initial pitch of adjacent microlenses of the microlens array 5 is 10 μm. The optical surface of the micro lens is a deformed aspheric surface, the curvature radius of the micro lens in the X direction is 200 mu m, and the cone coefficient is-1.5; the curvature radius of the microlens in the Y direction was 200 μm, and the conic coefficient was-1.5. The surface structure of the resulting microlens array 5 is schematically shown in fig. 7.

In this embodiment, referring to fig. 8, after being homogenized by the micro lens array 5, the light beam emitted by the light source 1 is diverged by the first lens 2, and then converged by the second lens 3 to form a light spot. Referring to fig. 9, fig. 9(a) shows a light spot 250nm away from the light source 1 from the second lens 3, where the light spot is h/L according to tan (θ/2), where h is a half height of the light spot, and L is a position away from the light uniformizing structure. The X direction of the light spot reaches a peak value at 55.7 degrees, the peak energy is 114% of the central energy, the Y direction reaches a peak value at 49.4 degrees, the peak energy is 114% of the central energy, the energy in the X direction is reduced to 80% of the central energy at 71 degrees, and the field angle is 80 degrees when the energy is reduced to 0; the Y direction had 80% of the energy dropped to the central energy at 56.7 degrees and the field angle was 78 ° at 0.

Referring to fig. 10, the light exit aperture 1mm away from the side of the second lens 3 away from the light source 1 is 1.16 mm.

EXAMPLE III

Referring to fig. 11 to 14, the light-emitting module 100 in the present embodiment includes a light source 1, a first lens 2 and a second lens 3.

Wherein, the refractive index of the first lens 2 and the second lens 3 is 1.52. The first lens 2 is a biconcave lens and the second lens 3 is a biconvex lens. The distance between the light source 1 and the side of the first lens 2 close to the light source 1 is 0.4mm, and the distance between the side of the first lens 2 far away from the light source 1 and the side of the second lens 3 close to the light source 1 is 0.5 mm.

In this embodiment, referring to fig. 12, a light beam emitted from a light source 1 is diverged by a first lens 2 and converged by a second lens 3 to form a light spot. Referring to fig. 13, fig. 13(a) shows a light spot 250nm away from the light source 1 from the second lens 3, where the light spot is h/L according to tan (θ/2), where h is the half height of the light spot, and L is the position of the light homogenizing structure. The X direction of the light spot reaches a peak value at 60 degrees, the peak energy is 116% of the central energy, the Y direction reaches a peak value at 40 degrees, the peak energy is 117% of the central energy, the energy of the X direction is reduced to 80% of the central energy at 69 degrees, and the field angle is 85 degrees when the energy is reduced to 0; the energy in the Y direction is reduced to 80% of the central energy at 58 degrees, and the field angle is 80 ° when the energy is reduced to 0. (ii) a

Referring to fig. 14, the light exit aperture 1mm away from the side of the second lens 3 away from the light source 1 is 1.05 mm.

Example four

Referring to fig. 16 to 18, the light-emitting module 100 in the present embodiment includes a light source 1, a first lens 2 and a second lens 3.

Both the first lens surface 21 and the second lens surface 22 of the first lens 2 are anamorphic aspherical surfaces. The curvature radius of the first lens surface 21 in the X direction is 10mm, and the conic coefficient is-2; the curvature radius of the first lens surface 21 in the Y direction is 10mm, and the conic coefficient is-2; the curvature radius of the second lens surface 22 in the X direction is 0.357mm, and the conic coefficient is-3; the second lens surface 22 has a radius of curvature of 0.357mm in the Y direction and a conic coefficient of-3.

The third lens surface 31 and the fourth lens surface 32 of the second lens 3 are both anamorphic aspherical surfaces. The curvature radius of the third lens surface 31 in the X direction is 0.4878mm, and the conic coefficient is-2; the curvature radius of the third lens surface 31 in the Y direction is 0.5263mm, and the conic coefficient is-2; the curvature radius of the fourth lens surface 32 in the X direction is 0.2mm, and the conic coefficient is-2.5; the fourth lens surface 32 has a radius of curvature of 0.4mm in the Y direction and a conic coefficient of-2.5.

In this embodiment, referring to fig. 6, a light beam emitted from a light source 1 is diverged by a first lens 2 and converged by a second lens 3 to form a light spot. Referring to fig. 17, fig. 17(a) shows a light spot 250nm away from the light source 1 from the second lens 3, where the light spot is h/L according to tan (θ/2), where h is the half height of the light spot, and L is the position of the light homogenizing structure. The X direction of the light spot reaches a peak value at 53.8 degrees, the peak energy is 122% of the central energy, the Y direction reaches a peak value at 40 degrees, the peak energy is 107% of the central energy, the energy of the X direction is reduced to 80% of the central energy at 78 degrees, and the field angle is 98 degrees when the energy is reduced to 0; the Y direction has an energy drop of 80% of the central energy at 51 degrees and a field angle of 72.4 ° at 0.

Referring to fig. 18, the light exit aperture 1mm away from the side of the second lens 3 away from the light source 1 is 1.86 mm.

The comparison between the first embodiment and the second embodiment shows that the light spots obtained by the microlens array 5 on the side of the substrate away from the light source 1 are lighter than the light spots obtained by the microlens array 5 on the side of the substrate close to the light source 1, and the light fields obtained by the two combination methods have approximately the same distribution under the condition that the parameters of the first lens 2, the second lens 3 and the microlenses are the same.

Through comparison between the first embodiment and the second embodiment and the third embodiment, it can be seen that, in the case where the microlens array 5 is not added, the fringe phenomenon generated by the light exit module 100 is significantly reduced, the energy distribution of the light spot is slightly changed, and the light exit aperture is reduced.

Compared with the third embodiment, it can be seen that the light spot energy distribution is changed by changing the surface type parameters of the first lens 2 and the second lens 3, and the light exit aperture size is changed, so as to realize a smaller light exit aperture.

The utility model also provides a TOF imaging device which comprises the light emitting module and the receiving module, wherein the light emitting module is used for emitting projection light to a target object, and the receiving module is used for receiving reflected light formed by reflecting the projection light by the target object. The TOF imaging device may be any of ietf, pTOF or dTOF, widening the range of applications of the TOF imaging device.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The utility model provides a light-emitting module, is adapted to TOF imaging device, its characterized in that, the light-emitting module includes:

a light source for emitting a light beam;

a first lens having a negative focal power;

a second lens having a positive refractive power;

2. The light extraction module of claim 1, wherein the first lens is a plano-concave lens or a biconcave lens, the radius of curvature of the first lens surface in the X direction is 1mm to 50mm, and the conic coefficient is-8 to 1; the curvature radius of the first lens surface in the Y direction is 1 mm-50 mm, and the cone coefficient is-8-1; the curvature radius of the second lens surface in the X direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the second lens surface in the Y direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1.

3. The light exit module of claim 1, wherein the second lens is a biconvex lens, the radius of curvature of the third lens surface in the X direction is 0.1mm to 1mm, and the conic coefficient is-5 to-1; the curvature radius of the third lens surface in the Y direction is 0.1 mm-1 mm, and the cone coefficient is-5 to-1; the curvature radius of the fourth lens surface in the X direction is 0.05 mm-0.8 mm, and the coefficient of the cone is-5-1; the curvature radius of the fourth lens surface in the Y direction is 0.05 mm-0.8 mm, and the cone coefficient is-5-1.

4. The light exit module of claim 1 wherein the first lens has a refractive index of 1.5 to 1.8; the refractive index of the second lens is 1.5-1.8; the thickness of the first lens is 0-0.1 mm, and the optical diameter is 0-2 mm; the thickness of the second lens is 0-2 mm, and the optical diameter is 0-2.5 mm; the distance between the light source and one side of the first lens, which is close to the light source, is 0.05 mm-0.8 mm; the distance between one side of the first lens, which is far away from the light source, and one side of the second lens, which is close to the light source, is 0.4-1 mm.

5. The light exit module of claim 1 wherein a micro-lens array is further disposed between the light source and the first lens.

6. The light exit module of claim 5 wherein the microlens array comprises a plurality of microlenses, and the microlenses have an anamorphic aspheric surface.

7. The light exit module of claim 6 wherein the microlens has a radius of curvature in the X direction of 10 μm to 300 μm, a conic coefficient of-0.95 to-8; the curvature radius of the micro lens in the Y direction is 10-300 mu m, and the cone coefficient is-0.95-8.

8. The light extraction module of claim 5, wherein the refractive index of the micro lens array is 1.5-1.8, and the distance between the light source and the side of the micro lens array close to the light source is 0.05-0.2 mm; the distance between one side of the micro lens array, which is far away from the light source, and one side of the first lens, which is close to the light source, is 0.1-0.5 mm.

9. A TOF imaging apparatus comprising a light exit module according to any of claims 1 to 8.