CN112578483A

CN112578483A - VCSEL beam expanding lens and VCSEL device

Info

Publication number: CN112578483A
Application number: CN201910941703.7A
Authority: CN
Inventors: 黄伟; 曹宇星; 汪洋
Original assignee: Raysees Technology Shenzhen Co ltd
Current assignee: Shenzhen Sunlight Technology Co ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2021-03-30
Anticipated expiration: 2039-09-30
Also published as: CN112578483B

Abstract

The invention discloses a VCSEL beam expanding lens and a VCSEL device, wherein the lens is provided with a cavity provided with a chip, an opening of the cavity is arranged at the bottom of the lens, the cavity wall of the cavity comprises a first refraction curved surface, a second refraction curved surface is formed at the top of the lens, and the first refraction curved surface is used for performing first refraction on a light beam emitted by the chip, wherein the first refraction curved surface is used for performing first refraction on the light beam, the divergence angle of the long-axis light beam is increased and the convergence angle of the short-axis light beam is decreased, so that the light beam is projected to the second refraction curved surface by; the second refraction curved surface is used for performing second refraction on the light beam projected on the second refraction curved surface, wherein the divergence angle of the long-axis light beam is increased, and the folding angle of the short-axis light beam is decreased, so that the light-emitting angle of the light beam is shaped to a preset light-emitting angle and a light spot effect, the light loss is avoided, the light efficiency is improved, and the product safety is improved; the lens can be directly arranged on the base without designing an additional supporting structure.

Description

VCSEL beam expanding lens and VCSEL device

Technical Field

The invention relates to the technical field of photoelectricity, in particular to a VCSEL beam expanding lens and a VCSEL device.

Background

At present, a VCSEL (Vertical Cavity Surface Emitting Laser) chip adopts an engineering beam expander (diffuiser) to expand the beam, wherein the engineering beam expander is formed by adhering a polymer layer 102 on the Surface of a flat glass 101 and performing light diffusion by using a micro-refraction technique (including refraction and diffraction), as shown in fig. 1. Because the total reflection of the plate glass 101 is more, and the microstructure of the upper polymer layer 102 is added, the optical loss is caused, and in the actual test, the optical loss of the VCSEL chip after being expanded by the engineering beam expander is more than 10%, so the light-emitting efficiency is lower. Moreover, the polymer layer 102 is easy to melt at high temperature and fall off or fails due to glue infiltration and pollutant filling, laser beams with extremely high energy are directly irradiated out, and potential safety hazards of human eyes exist during use.

Disclosure of Invention

The present invention is directed to provide a VCSEL beam expanding lens and a VCSEL device, which address the above-mentioned drawbacks of the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a VCSEL beam expanding lens, wherein the lens is provided with a cavity for arranging a VCSEL chip, an opening of the cavity is arranged at the bottom of the lens, the cavity wall of the cavity comprises a first refraction curved surface, a second refraction curved surface is formed at the top of the lens, and the first refraction curved surface is used for performing first refraction on a light beam emitted by the chip, wherein the first refraction curved surface is used for performing first refraction on the light beam, the divergence angle of the long-axis light beam is increased, and the convergence angle of the short-axis light beam is decreased, so that the light beam is projected to the second refraction curved surface close to a preset light; the second refraction curved surface is used for performing second refraction on the light beam projected on the second refraction curved surface, wherein the divergence angle of the long-axis light beam is increased, and the folding angle of the short-axis light beam is decreased, so that the light-emitting angle of the light beam is shaped to a preset light-emitting angle and a light spot effect.

Preferably, an outline of the first refractive curved surface in the first vertical plane is an N-th power curve, an outline of the second refractive curved surface in the first vertical plane where the long axis of the lens is located is an M-th power curve, M is an integer greater than or equal to 4, and N is an integer greater than or equal to 2;

the distance between the first refraction curved surface and the second refraction curved surface is gradually increased from the center of the long axis to two sides in the first vertical plane.

Preferably, the curve of power N is in particular a curve of power 2, the ratio of height to length H1/L1 being between 1.2 and 1.5; the M-power curve is a 4-power curve, and the ratio H21/H22 of the height of the highest point at two sides to the height of the lowest point in the middle is 1.0-3.0.

Preferably, the height to length ratio H1/L1 is 1.31 and the height ratio H21/H22 is 2.17.

Preferably, an outline of the first curved refractive surface in a second vertical plane in which a short axis of the lens is located is an R-power curve, an outline of the second curved refractive surface in the second vertical plane is an S-power curve, and R, S is an integer greater than or equal to 2;

and the distance between the first refraction curved surface and the second refraction curved surface is gradually reduced from the center of the short shaft to two sides in the second vertical plane.

Preferably, the curve with power S is a curve with power 2, and the ratio of the height to the length H3/L3 is less than 0.1; the R power curve is a 2 power curve, and the ratio of the height to the length H4/L4 is 0.1-0.5.

Preferably, the height to length ratio H3/L3 is 0.077 and the height to length ratio H4/L4 is 0.13.

Preferably, the whole cavity wall of the cavity body is composed of the first refraction curved surface and a pair of vertical planes, the pair of vertical planes are arranged oppositely and parallel to the long axis of the lens, and the first refraction curved surface is connected between the pair of vertical planes.

Preferably, the lens is formed by injection molding or die pressing, and the refractive index n of the lens is greater than 1.4.

In another aspect, the invention provides a VCSEL device, which includes a VCSEL chip, a base, and a beam expanding lens, where the beam expanding lens is the lens as described in any of the above, the beam expanding lens is directly disposed on the base, and the chip is disposed on the base and located in the cavity.

The VCSEL beam expanding lens and the VCSEL device have the following beneficial effects: the beam expander utilizes the two refraction curved surfaces to perform refraction for increasing the divergence angle of the long-axis light beam and reducing the furling angle of the short-axis light beam twice, expands the light beam emitted by the VCSEL chip and shapes the light emergent angle of the light beam to the preset light emergent angle and light spot effect, compared with the existing beam expander, the beam expander can avoid light loss and improve the light efficiency while realizing beam expansion, and can completely solve the hidden trouble that the laser beam with extremely high energy is directly irradiated out due to the failure of a macromolecular layer in the prior art, thereby improving the product safety; in addition, the cavity can be provided with the VCSEL chip, so that the supporting structure of the beam expander in the prior art can be reduced, and the lens in the invention can be directly arranged above the base without designing an additional supporting structure.

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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:

FIG. 1 is a schematic diagram of a prior art VCSEL device;

FIG. 2 is a schematic diagram of the structure of a VCSEL device of the present invention;

FIG. 3 is a long-axis cross-sectional view of a VCSEL device of the present invention;

FIG. 4 is a long-axis cross-sectional view of a lens of the present invention;

FIG. 5 is a graph of the power M;

FIG. 6 is a schematic diagram of a power N curve;

FIG. 7 is a short axis cross sectional view of a VCSEL device of the present invention;

FIG. 8 is a short axis cross-sectional view of a lens of the present invention;

FIG. 9 is a schematic diagram of the R power curve;

FIG. 10 is a graph of the power S;

FIG. 11 is a long axis optical path diagram;

FIG. 12 is a short axis optical path diagram;

FIG. 13 is a pattern of spots resulting from the simulation;

FIG. 14 is a light distribution diagram of a simulation result in polar coordinates;

fig. 15 is a light distribution diagram of a simulation result in cartesian coordinates.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Exemplary embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Note that, the long axis in this document represents a direction in which the light distribution angle is large, and the short axis represents a direction in which the light distribution angle is small. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The terms including ordinal numbers such as "first", "second", and the like used in the present specification may be used to describe various components, but the components are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from other constituent elements. For example, a first component may be named a second component, and similarly, a second component may also be named a first component, without departing from the scope of the present invention.

The general concept of the invention is: constructing a VCSEL beam expanding lens, wherein the lens is provided with a cavity for arranging a VCSEL chip, an opening of the cavity is arranged at the bottom of the lens, the cavity wall of the cavity comprises a first refraction curved surface, a second refraction curved surface is formed at the top of the lens, and the first refraction curved surface is used for performing first refraction on a light beam emitted by the chip, wherein the first refraction curved surface is used for performing first refraction on the light beam, the divergence angle of the long-axis light beam is increased, and the convergence angle of the short-axis light beam is decreased, so that the light beam is projected to the second refraction curved surface close to a preset light; the second refraction curved surface is used for performing second refraction on the light beam projected on the second refraction curved surface, wherein the divergence angle of the long-axis light beam is increased, and the folding angle of the short-axis light beam is decreased, so that the light-emitting angle of the light beam is shaped to a preset light-emitting angle and a light spot effect. Compared with the existing beam expander, the beam expander can avoid light loss and improve light efficiency while realizing beam expansion, can completely solve the hidden trouble that laser beams with extremely strong energy are directly irradiated out due to failure of a macromolecular layer in the prior art, and improves the safety of products; moreover, because the cavity can be provided with the VCSEL chip, the supporting structure of the beam expander in the prior art can be reduced, and the lens in the invention can be directly arranged above the chip without designing an additional supporting structure.

In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the specific embodiments of the specification, and it should be understood that the embodiments and specific features of the embodiments of the present invention are detailed descriptions of the technical solutions of the present application, and are not limited to the technical solutions of the present application, and the technical features of the embodiments and examples of the present invention may be combined with each other without conflict.

Referring to fig. 2, 3 and 7, the VCSEL device of the present invention includes a submount 3, a VCSEL chip 2 and a VCSEL beam expander lens 1. The lens 1 is made of transparent glue with the refractive index larger than 1.4 and can resist high temperature. The lens 1 is formed by injection molding or compression molding.

Referring to fig. 3 and 7, the lens 1 has a cavity 10 for setting the VCSEL chip 2, the opening of the cavity 10 is set at the bottom of the lens 1, the cavity wall of the cavity 10 includes a first curved refraction surface 11, specifically, the whole cavity wall of the cavity 10 is composed of the first curved refraction surface 11 and a pair of vertical planes 13, the pair of vertical planes 13 is opposite to the long axis of the lens and parallel to the long axis of the lens, and the first curved refraction surface 11 is connected between the pair of vertical planes 13.

The top of the lens 1 forms a second refraction curved surface 12.

The lens 1 is directly disposed on the base 3, and the chip 2 is disposed on the base 3 and located in the cavity 10. The existence of the cavity 10 enables the lens 1 of the present invention to be directly placed on the base 3 and to secure the mounting space of the chip 2 without designing an additional holding structure to provide the mounting space for the chip 2 on the base 3.

The first refraction curved surface 11 is used for performing first refraction on the light beam emitted by the chip, wherein the divergence angle of the long-axis light beam is increased, and the convergence angle of the short-axis light beam is decreased, so that the light beam is projected to the second refraction curved surface 12 at a preset light emitting angle. The term "approaching the preset light-emitting angle" means that the difference between the preset light-emitting angle and the preset light-emitting angle is within a reasonable range, for example, if the preset light-emitting angle of the long axis is 120 ° and the reasonable range is 10 °, the approach to the preset light-emitting angle is within a range of 110 ° to 130 °.

The second refraction curved surface 12 is configured to perform a second refraction on the light beam projected thereon, where the divergence angle of the long-axis light beam is increased and the convergence angle of the short-axis light beam is decreased, so as to shape the light exit angle of the light beam to a preset light exit angle. For example, the predetermined light-emitting angle is typically about 120 ° by 12 °, although the specific values are not limited to absolute equality or equality in mathematical terms, and may be similar in engineering sense or within an acceptable error range.

Preferably, an outline of the first curved refractive surface 11 in a first vertical plane in which a long axis of the lens is located is an N-th power curve, and N is an integer equal to or greater than 2. Specifically, referring to fig. 4 and 5, in the embodiment, the N-power curve is a 2-power curve, and the ratio of the height to the length H1/L1 is 1.2 to 1.5. The height of the 2-power curve refers to the span of the 2-power curve along the vertical direction, and the length of the 2-power curve refers to the span of the 2-power curve in the horizontal plane. In this embodiment, the ratio of the height to the length of the 2-power curve is H1/L1 equal to 1.31.

Preferably, an outline of the second curved refractive surface 12 in a first vertical plane in which a long axis of the lens is located is an M-th power curve, and M is an integer equal to or greater than 4. Referring to fig. 4-6, the orientations of the openings of the N-th power curve and the M-th power curve are the same, and both are downward, and the distance between the first refractive curved surface 11 and the second refractive curved surface 12 gradually increases from the center of the long axis to both sides in the first vertical plane, that is, the lens is thin in the middle and thick in both sides when viewed from the broken view of the long axis. Specifically, referring to fig. 6, the M-power curve is a 4-power curve, and the ratio H21/H22 between the height of the highest point on both sides and the height of the lowest point in the middle is 1.0 to 3.0. It is understood that the height herein refers to the distance from the lowest point of the two side boundaries of the entire 4-th-power curve. In this embodiment, the ratio of the height of the highest point on both sides of the 4-th-power curve to the height of the lowest point in the middle is H21/H22-2.17.

Preferably, an outline of the first curved refractive surface 11 in a second vertical plane in which a short axis of the lens is located is an R-power curve, and R is an integer greater than or equal to 2. Specifically, referring to fig. 8 and 9, in the embodiment, the R-power curve is a 2-power curve, and the ratio of the height to the length H3/L3 is less than 0.1. In this embodiment, the ratio of the height to the length of the 2-power curve is H3/L30.077.

Preferably, the second curved refractive surface 12 has an outline in a second vertical plane in which the minor axis of the lens is located, the outline being an S-th power curve, and S is an integer greater than or equal to 2. Referring to fig. 8-10, the open directions of the S-power curve and the R-power curve are opposite, one is downward and the other is upward, and the distance between the first curved refracting surface 11 and the second curved refracting surface 12 is gradually reduced from the center of the short axis to two sides in the second vertical plane where the short axis of the lens is located, i.e. the lens is thick in the middle and thin in two sides when viewed from the short axis broken view. Specifically, referring to fig. 8 and 10, in the embodiment, the S-power curve is a 2-power curve, and the ratio of the height to the length is 0.1 to 0.5. In this embodiment, the ratio of the height to the length of the 2-power curve is H4/L4 equal to 0.13.

Of course, the specific numerical values of this embodiment are only schematic, and we can realize arbitrary beam shaping by adjusting the first curved refraction surface 11 and the second curved refraction surface 12, and the angle can be smaller than the original angle of the VCSEL, which cannot be achieved by the existing beam expander. The lens of the invention has neat and smooth appearance design and is convenient for die processing and packaging process. The lens efficiency is higher than that of the traditional beam expander, so that the efficiency of the whole VCSEL device is higher. The cost of the lens is lower than that of the traditional beam expander, so that the cost of the whole VCSEL device is lower.

Fig. 11 to 15 show the effects of the present embodiment, fig. 11 is a long-axis optical path diagram, fig. 12 is a short-axis optical path diagram, fig. 13 is a simulation-result light spot diagram, fig. 14 is a simulation-result light distribution diagram in polar coordinates, and fig. 15 is a simulation-result light distribution diagram in cartesian coordinates. As can be seen from fig. 11 and 12, when the light beam passes through the two refraction curved surfaces, the divergence angle of the long-axis light beam becomes larger, and the convergence angle of the short-axis light beam becomes smaller. Referring to fig. 13, the aspect ratio of the spot is 120:12, i.e., about 12: 1. Referring to fig. 14-15, where the line F1 represents the simulation results for the major axis and F2 represents the simulation results for the minor axis, the visible light distribution angle is approximately 105 × 9.5 degrees.

In summary, the VCSEL beam expanding lens and the VCSEL device of the present invention have the following advantages: the beam expander utilizes the two refraction curved surfaces to perform refraction for increasing the divergence angle of the long-axis light beam and reducing the furling angle of the short-axis light beam twice, expands the light beam emitted by the VCSEL chip and shapes the light emergent angle of the light beam to the preset light emergent angle and light spot effect, compared with the existing beam expander, the beam expander can avoid light loss and improve the light efficiency while realizing beam expansion, and can completely solve the hidden trouble that the laser beam with extremely high energy is directly irradiated out due to the failure of a macromolecular layer in the prior art, thereby improving the product safety; in addition, the cavity can be provided with the VCSEL chip, so that the supporting structure of the beam expander in the prior art can be reduced, and the lens in the invention can be directly arranged above the base without designing an additional supporting structure.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A VCSEL beam expander lens, wherein the lens has a cavity (10) for accommodating a VCSEL chip (2), an opening of the cavity (10) is disposed at the bottom of the lens, a cavity wall of the cavity (10) includes a first curved refraction surface (11), a second curved refraction surface (12) is formed at the top of the lens, and the first curved refraction surface (11) is used for performing a first refraction of a light beam emitted from the chip (2) to increase a divergence angle of the long axis light beam and decrease a convergence angle of the short axis light beam, so that the light beam is projected to the second curved refraction surface (12) close to a preset light-emitting angle; the second refraction curved surface (12) is used for performing second refraction on the light beam projected on the second refraction curved surface, wherein the divergence angle of the long-axis light beam is increased, and the folding angle of the short-axis light beam is decreased, so that the light-emitting angle of the light beam is shaped to a preset light-emitting angle and a light spot effect.

2. The lens according to claim 1, wherein the first refractive curved surface (11) has an outline in the first vertical plane of an N-th power curve, the second refractive curved surface (12) has an outline in the first vertical plane of the long axis of the lens of an M-th power curve, M is an integer of 4 or more, and N is an integer of 2 or more;

the distance between the first refraction curved surface (11) and the second refraction curved surface (12) is gradually increased from the center of the long axis to two sides in the first vertical plane.

3. The lens according to claim 2, wherein the N-power curve is in particular a 2-power curve having a height to length ratio H1/L1 of 1.2 to 1.5; the M-power curve is a 4-power curve, and the ratio H21/H22 of the height of the highest point at two sides to the height of the lowest point in the middle is 1.0-3.0.

4. The lens of claim 3 wherein the height to length ratio H1/L1 is 1.31 and the height ratio H21/H22 is 2.17.

5. The lens according to claim 1, characterized in that the profile of the first refractive curved surface (11) in a second vertical plane in which the minor axis of the lens lies is an R-power curve, the profile of the second refractive curved surface (12) in the second vertical plane is an S-power curve, and R, S is an integer greater than or equal to 2;

the distance between the first refraction curved surface (11) and the second refraction curved surface (12) is gradually reduced from the center of the short shaft to two sides in the second vertical plane.

6. The lens according to claim 5, characterized in that the S-power curve is in particular a 2-power curve having a height to length ratio H3/L3 of less than 0.1; the R power curve is a 2 power curve, and the ratio of the height to the length H4/L4 is 0.1-0.5.

7. The lens of claim 6 wherein the height to length ratio H3/L3 is 0.077 and the height to length ratio H4/L4 is 0.13.

8. Lens according to claim 1, characterized in that the entire wall of said cavity (10) is composed of said first curved refracting surface (11) and a pair of vertical planes (13), said pair of vertical planes (13) being arranged opposite and parallel to the long axis of the lens, said first curved refracting surface (11) being connected between said pair of vertical planes (13).

9. The lens of claim 1, wherein the lens is an injection or compression molded light transmitting adhesive having a refractive index n greater than 1.4.

10. A VCSEL device, characterized in that it comprises a VCSEL chip (2), a pedestal (3) and a beam expanding lens (1), said beam expanding lens (1) being a lens according to any of claims 1-9, the beam expanding lens (1) being directly disposed on said pedestal (3), said chip (2) being disposed on said pedestal (3) and being located within said cavity (10).