A collimating lens for eliminating stray light

Abstract

The present invention discloses a collimating lens for eliminating stray light, comprising a first incident surface, a second incident surface, a first exit surface, a second exit surface, and a total reflection surface. Each point on an incident curve, obtained by intersecting the second incident surface with a plane passing through the optical axis, has a negative slope. As the incident curve extends from bottom to top, the absolute value of its slope gradually decreases to a first inflection point and then gradually increases. The present invention first overcomes the first type of stray light by using the gradually sloped inner cavity side surfaces. Furthermore, the second type of stray light is suppressed by combining the outwardly convex first incident surface and first exit surface.

Description

Technical Field

[0001] The invention belongs to the field of LED light distribution lenses, and in particular relates to a collimating lens for eliminating stray light. Background Art

[0002] In existing LED optical solutions, the anti-glare performance of lenses is gaining increasing attention to meet the needs of human eye comfort. Among various anti-glare technology approaches, total internal reflection (TIR) ​​lenses are the most popular because they maximize the use of light energy and achieve higher optical efficiency. TIR lens technology, as described in patent US6547423B2, divides the light path into two parts: one is light incident from the top and refracted out; the second part enters the lens from the side, is totally reflected by the side cup surface, and then emerges from the curved surface near the top near both sides. From the perspective of energy distribution, the second part of the light path accounts for the larger portion.

[0003] However, the anti-glare performance of this type of total reflection lens currently has significant problems, especially at small angles. The lens beam angle is within 25 degrees, which means that the anti-glare angle is very small. In other words, no bright glare spots can be seen beyond 35-40 degrees. The total reflection lens technology solutions currently on the market are difficult to meet the relevant application requirements. The technology of the present invention provides a small-angle collimating total reflection lens to prevent glare.

[0004] Total reflection lenses can make the most of light energy, but the inner cavity surface is composed of two parts, which will cause glare of various mechanisms. Normally, glare occurs in the range of 30 to 60 degrees. The range of glare is different for different light spot emission angles. For high-end lighting needs, the smaller the angle, the larger the angle range where glare cannot be formed, and the higher the challenge to optical design. Among them, the glare point of the collimating optical system (angle less than 25 degrees) must be controlled within 30-35 degrees, that is, no glare point can be seen outside 35 degrees. However, since there are two groups of light rays, transmitted light and reflected light, on the surface of the optical lens, the optical surface can only control the light that transmits most of the energy, and the reflected light will lose control to form stray light or glare. This type of glare is the most difficult to eliminate in optical design. When it comes to total reflection (TIR) ​​lenses, there are two types of typical stray light: one is like Figure 1 The light shown in the figure is the Fresnel loss reflected light reflected from the side cavity 13, which will penetrate the other side of the curved surface and enter the lens body. Then, it will be totally reflected by the total reflection surface 14 of the lens cup surface and then transmitted from the second exit surface 15 above the cup surface. It is hereinafter referred to as the "first type of stray light". The second type is as follows. Figure 2The light shown is reflected by Fresnel loss from the side cavity 23, passes upward through the first incident surface 21, and then exits through the first exit surface 22. This is referred to as "second type of stray light." Both types of stray light deviate from the main optical path, forming a spot distribution within a range of 30 to 60 degrees. This creates stray light during wall washing and causes glare when observing the lens surface with the naked eye.

[0005] The causes of stray light are complex and varied. After research, the inventors proposed the "third type of stray light". Most of the existing total reflection lenses have a top edge, that is, a structural edge extends from the outer edge of the total reflection surface and the output surface, such as Figure 2 The structure is composed of three straight edges 17, 18 and 19. The setting of this structural edge has several functions: 1. It is convenient for mold design and demoulding; 2. It is convenient to add brackets and other lens mounting structures on the edge. However, this outward extending structural edge is easy to cause the following Figure 3 The "third type of stray light" shown. This type of stray light leaks from the lens cup surface to the edge. Due to the expansibility of the light source, the light near the light source is difficult to be completely controlled by the total reflection cup surface, and a part of the light will pass through the tir cup surface and enter the edge of the structure, as shown by light 31. Since the upper end of the structure edge is a plane, the angle between the normal direction of the plane and the glancing light 31 entering here is often greater than the total reflection angle of the lens material, so that the light 31 is trapped inside the lens to form total reflection; the totally reflected light will form a light guide phenomenon at the edge of the structure, and finally emit from the light exit surface of the lens to form the third type of stray light 32. This part of stray light is difficult to block, and often directly emits from the lamp to form hook-shaped stray light, such as Figure 3 The large V-shaped bright area shown. Summary of the Invention

[0006] In view of the problems in the related art, the present invention designs a collimating lens for eliminating stray light to overcome the existing technical problems described in the above background technology.

[0007] The solution adopted is: a collimating lens for eliminating stray light, comprising a lens body that is rotationally symmetrical along a central optical axis, a concave cavity with an opening facing a light source provided at the lower end of the body, the top of the concave cavity forming a first incident surface, and an annular side surface of the concave cavity forming a second incident surface; a first exit surface located in the middle corresponding to the first incident surface, and a second exit surface located on the circumferential side of the first exit surface corresponding to the second incident surface provided at the upper end of the body, and the circumferential side surface of the body forming a total reflection surface facing the second exit surface; small-angle light emitted by the light source enters the lens body from the first incident surface and is collimatedly emitted from the first exit surface; large-angle light emitted by the light source is refracted from the second incident surface into the lens body and is emitted to the total reflection surface, which is then reflected to the second exit surface and collimatedly emitted;

[0008] The slope of each point on the incident curve intercepted by the intersection of the second incident surface and the plane passing through the optical axis is negative. As the incident curve extends from the bottom to the top, the absolute value of its slope first gradually decreases to the first inflection point and then gradually increases.

[0009] Preferably, the angle between the line connecting the top of the incident curve and the center of the light source and the optical axis is greater than 25 degrees and less than 45 degrees; the angle between the line connecting the bottom of the incident curve and the center of the light source and the optical axis is greater than 75 degrees and less than 90 degrees; the absolute value of the slope of the starting point of the bottom end of the incident curve is not less than 6.

[0010] Preferably, the angle between the line connecting the first inflection point and the center of the light source and the optical axis is not less than 50 degrees and not more than 65 degrees.

[0011] Preferably, the slope of the emission curve intercepted by the second emission surface and the plane passing through the optical axis is positive, and in the process of extending from the inside to the outside to the edge, the slope first gradually increases to the second inflection point and then gradually decreases.

[0012] Preferably, the ratio of the diameter D of the outer peripheral edge of the second exit surface to the height difference H between the edge of the second exit surface and the center of the light source satisfies: 0.45 <H / D<0.65。

[0013] Preferably, the ratio of the diameter d of the circle formed by the second inflection point of each emission curve along the circumferential direction to the diameter D of the outer peripheral edge of the second emission surface satisfies: 0.65 <d / D<0.85。

[0014] Preferably, the emission curve extends from the middle to the edge, and the slopes of the starting point closest to the middle and the end point closest to the edge are both no greater than 2.7.

[0015] Preferably, the first incident surface is a curved surface convex toward the light source; the first exit surface is a curved surface convex away from the light source, and the height difference dh between the highest point and the lowest point of the bottom of the convex curved surface, and the proportional relationship with the aperture d1 of the outer edge of the first exit surface satisfies: dh / d1<0.35.

[0016] Preferably, the slope of the edge point of the section obtained by the intersection of the first incident surface and the plane passing through the optical axis is not less than 0.2.

[0017] Preferably, an extension portion is provided on the outer edge of the periphery of the lens body connecting the total reflection surface and the second emitting surface, and the extension portion includes a planar extended upper optical surface, a vertical side surface and a lower optical surface, and the lower optical surface is a curved surface that first extends downward and then pulls upward.

[0018] Preferably, an angle formed by a line connecting the top of the second incident surface and the top of the total reflection surface and a tangent line of the lower optical surface at the intersection of the lines satisfies the following condition: the angle is greater than 60° and less than 120°.

[0019] Preferably, one or more curved surfaces among the first incident surface, the first exit surface and the second exit surface are provided with a bead-shaped microstructure; and the second incident surface and / or the total reflection surface are scaly microstructure surfaces.

[0020] The present invention overcomes the first type of stray light by using the gradually sloped inner cavity side surface and controls the lens height. Furthermore, the outwardly convex first incident surface and first exit surface are combined to suppress the second type of stray light. Unlike the first type of stray light, the second type of stray light does not need to be completely eliminated. This solution simply "drives" the second type of stray light beyond 60 degrees. When the lamp is manufactured, the lamp housing can easily block this part of the stray light. Furthermore, the third type of stray light is detected and overcome. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the principle of generation of the first type of stray light referred to in the present invention;

[0022] Figure 2 Schematic diagram of the principle of generation of the second type of stray light referred to in the present invention;

[0023] Figure 3 Schematic diagram of the principle of generation of the third type of stray light referred to in the present invention;

[0024] Figure 4 This is the spot effect diagram of the third type of stray light;

[0025] Figure 5 This is a principle diagram of the optical path of the collimating lens of the present invention for the first type of stray light;

[0026] Figure 6 This is a principle diagram of the optical path of the collimating lens of the present invention for the second type of stray light;

[0027] Figure 7 Another optical path principle diagram of the collimating lens of the present invention for the second type of stray light;

[0028] Figure 8 Schematic diagram of the structure of the collimating lens of Example 1 of the present invention;

[0029] Figure 9 Schematic diagram of the structure of the collimating lens of Example 2 of the present invention;

[0030] Figure 10 Schematic diagram of the partial structure of the collimating lens according to Example 3 of the present invention;

[0031] Figure 11Schematic diagram of the partial structure of the collimating lens according to Example 3 of the present invention;

[0032] Figure 12 Schematic diagram of the partial structure of the collimating lens according to Example 3 of the present invention;

[0033] Figure 13 Schematic diagram of the partial structure of the collimating lens according to Example 3 of the present invention;

[0034] Description Figure Numbers:

[0035] First incident surface 11, 21, 51, 61;

[0036] Second incident surface 13, 23, 33, 43, 53, 63;

[0037] First exit surface 12, 22, 35, 42, 52, 62;

[0038] Second exit surface 15, 55, 65;

[0039] Total reflection surface 14, 34, 54, 64;

[0040] Upper optical surface 71, 81, side elevation 73, 83, lower optical 72, 82. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] like Figures 5 to 9 As shown, the collimating lens of this embodiment includes a lens body that is rotationally symmetrical along the central optical axis, a concave cavity with an opening facing the light source is provided at the lower end of the body, the top of the concave cavity is formed as a first incident surface, and the annular side surface of the concave cavity is formed as a second incident surface; a first exit surface located in the middle corresponding to the first incident surface, and a second exit surface located on the circumferential side of the first exit surface corresponding to the second incident surface are provided at the upper end of the body, and the circumferential side surface of the body is formed as a total reflection surface facing the second exit surface; small-angle light emitted by the light source enters the lens body from the first incident surface and is collimatedly emitted from the first exit surface; large-angle light emitted by the light source is refracted into the lens body from the second incident surface and is emitted to the total reflection surface, and the total reflection surface is then reflected to the second exit surface and collimatedly emitted; the slope of each point on the incident curve intercepted by the intersection of the second incident surface and the plane passing through the optical axis is negative, and in the process of the incident curve extending from the bottom to the top, the absolute value of its slope first gradually decreases to the first inflection point and then gradually increases.

[0043] The angle between the line connecting the top of the incident curve and the center of the light source and the optical axis is greater than 25 degrees and less than 45 degrees; the angle between the line connecting the bottom of the incident curve and the center of the light source and the optical axis is greater than 75 degrees and less than 90 degrees; the absolute value of the slope of the starting point of the bottom of the incident curve is not less than 6. The angle between the line connecting the first inflection point and the center of the light source and the optical axis is not less than 50 degrees and not more than 65 degrees.

[0044] The slope of the exit curve intercepted by the second exit surface and the plane passing through the optical axis is positive. The ratio of the diameter D of the outer edge of the second exit surface to the height difference H between the edge of the second exit surface and the center of the light source satisfies: 0.45 <H / D<0.65。

[0045] The slope of the edge point of the section obtained by the intersection of the first incident surface and the plane passing through the optical axis is not less than 0.2.

[0046] One or more curved surfaces among the first incident surface, the first exit surface and the second exit surface are provided with a bead-shaped microstructure; the second incident surface and / or the total reflection surface are scaly microstructure surfaces.

[0047] This embodiment is a technical solution based on a total reflection collimating lens, which designs a second incident surface (the side of the inner cavity) with a continuously changing slope, such as Figure 5 As shown in Figure 2, the absolute value of the slope of the incident curve changes from the bottom to the top in the following manner: first it gradually decreases, and then it gradually increases.

[0048] The specific principle of using this side cavity curve to eliminate stray light is as follows:

[0049] First, the absolute value of the bottom slope gradually decreases, which helps to reduce Figure 1 The first type of stray light. Figure 1 The first type of stray light is most likely to appear in light with a large angle to the optical axis, especially in light with an angle of 60-65 degrees to the optical axis. Figure 1 Therefore, the absolute value of the slope gradually decreases from the bottom to the top, and the absolute value of the slope reaches the minimum value when the first type of stray light is generated at the maximum position, that is, near the angle of 60-65 degrees with the optical axis, thereby minimizing the first type of stray light. Figure 5 As shown in the figure: after the first type of stray light is reflected by the inner cavity side surface (second incident surface) 33 where the absolute value of the slope of the incident curve gradually decreases, most of it cannot re-enter the lens body from the other side of the inner cavity side surface, such as light 311 and 312; even a small amount of light entering the lens body, such as light 313 in the figure, has a very small angle with the normal direction of the corresponding point of the total reflection surface when it is incident on the total reflection surface, and the main energy is refracted out of the lens from the total reflection surface 34, so that the first type of stray light is suppressed.

[0050] Secondly, starting from an angle of 60-65 degrees with the optical axis, the absolute value of the slope of the incident curve continues to increase. The advantage is that the inner cavity side (second incident surface) can control as much light as possible, thereby minimizing the height of the lens body, while also reducing the light energy leaking from the cup surface to the edge, which also helps to reduce the third type of stray light. Assuming that the inner cavity side curve is a straight line, the larger the absolute value of the slope of the incident curve, the smaller the cup surface diameter and the height in the same angle range. However, the larger the absolute value of the slope, the more serious the first type of stray light. Therefore, this embodiment gradually reduces the absolute value of the bottom slope, and then gradually increases it. This can greatly compensate for the loss of height and diameter caused by the smaller bottom slope, so that the overall height is not much different from other technical routes.

[0051] In addition to mitigating the first type of stray light and controlling lens height through the gradual slope change of the incident curve, this embodiment also incorporates a double-sided outwardly convex first incident surface and first exit surface to suppress the second type of stray light. Unlike the first type, the second type of stray light is eliminated by a different method. In this embodiment, the second type of stray light is simply "driven" beyond 60 degrees, and this portion of stray light can be shielded by the lamp housing in the later stage of the lamp.

[0052] like Figure 6 As shown, by using two curved surfaces that are raised up and down respectively, Figure 6 The second type of stray light is shown as being deflected to a greater angle as possible.

[0053] like Figure 6 As shown, the second type of stray light reflected by the upper end of the inner cavity side curved surface (second incident surface) 43, the light 401 refracted by the more downwardly protruding curved surface 411, and the light 402 refracted by the relatively flat curved surface 412 have a larger deflection angle of the light 401, so the first incident surface (inner cavity top curved surface) 41 adopts an outwardly protruding curved surface.

[0054] like Figure 6 and Figure 7 As shown, for the second type of stray light refracted by the first exit surface 42, the curved surface 421 is flatter than the curved surface 422, and the deflection angle of the light 403 emitted from the curved surface 421 is larger than that of the light 404 emitted from the curved surface 422, as shown in FIG. Figure 7 Therefore, the embodiment limits the height of the protrusion of the first exit surface, namely: the first incident surface is a curved surface that is convex toward the light source; the first exit surface is a curved surface that is convex away from the light source, and the height difference dh between the highest point and the lowest point of the curved surface is proportional to the diameter d1 of the outer edge of the first exit surface, satisfying the following relationship: dh / d1<0.35.

[0055] Through the above design of the first incident surface and the first exit surface, stray light rays of the second type can be deflected beyond 65 degrees, so that it can be conveniently blocked and eliminated by the lamp housing during lamp design.

[0056] Based on the above basic structure, a more specific structure of Extended Embodiment 1, Embodiment 2, and Embodiment 3 is designed as follows:

[0057] Extended Embodiment 1:

[0058] As Figure 8 shown, it is the structure of Extended Embodiment 1. The ratio of the height to the aperture of the lens body, the aperture D of the outer peripheral edge of the second exit surface, and the ratio of the height difference H between the edge of the second exit surface and the light source center satisfy: 0.45 < H / D < 0.65. In this Embodiment 1, H / D is approximately between 0.5 and 0.55.

[0059] In this Embodiment 1, the incident curve intercepted by the intersection of the second incident surface 53 of the collimating lens and the plane passing through the optical axis is a curve presenting an S shape. The angle 501 between the line connecting the top of the curve and the light source origin and the optical axis is greater than 30 degrees and less than 35 degrees. The slope of the incident curve is less than 0, and the absolute value of the slope gradually decreases from the bottom upwards and gradually increases after reaching the first inflection point. The angle 502 between the line connecting the first inflection point and the light source center and the optical axis is between 50 degrees and 65 degrees; the absolute value of the slope at the first inflection point position is not greater than 2.

[0060] In this Embodiment 1, the first incident surface 51 and the first exit surface 52 are curved surfaces protruding outwards. The ratio dh / d1 of the height difference dh between the highest point and the lowest point of the first exit surface 52 to the aperture d1 of the outer peripheral edge of the first exit surface is approximately 0.3, and the ratio d1 / D of d1 to the aperture D of the outer peripheral edge of the second exit surface 55 is approximately 0.25.

[0061] Another feature of this Embodiment 1 is that the exit curve intercepted by the second exit surface 55 through the optical axis plane gradually increases in slope from the middle to both sides until the second inflection point and then gradually decreases. The ratio of the diameter d of the circle formed by the second inflection points of each exit curve along the circumference to the aperture D of the outer peripheral edge of the second exit surface satisfies: 0.65 < d / D < 0.85, and the absolute values of the slopes of the starting point and the edge point of the exit curve are not greater than 2.7. The advantage of this is that it can limit the height of the lens from being too high and just make the stray light of the first type easier to penetrate through the lens cup surface.

[0062] Extended Embodiment 2:

[0063] As Figure 9FIG2 is a structural diagram of Example 2. Compared with Example 1, the main differences of this embodiment are that, first, the angle range controlled by the first incident surface 61 and the first exit surface 62 is larger, and the angle 601 between the line connecting the top of the second exit surface 63 and the light source origin and the optical axis is greater than 40 degrees and less than 45 degrees.

[0064] Another difference compared to Example 1 is that the second light exit surface 65 of Example 2 is a curve with a slope that increases continuously from the center to the edge. The increasing slope ensures that the first type of stray light can more easily penetrate from the side of the lens.

[0065] Extended Example 3:

[0066] like Figure 10 and Figure 11 As shown, this embodiment, as an additional characteristic structure, can be superimposed on any of the aforementioned embodiments to form a new embodiment. Figure 10 and Figure 11 Only a partial schematic diagram of the additional characteristic structure is shown, and the complete lens structure is not shown, because it can serve as an additional characteristic structure. The additional characteristic structure is:

[0067] An extension portion is provided at the outer edge of the periphery of the lens body connecting the total reflection surface and the second emitting surface. The extension portion includes an upper optical surface 71 extending along the horizontal plane, a vertical side surface 73 and a lower optical surface 72. The lower optical surface is a curved surface that first extends downward and then pulls upward.

[0068] The angle formed by the line RT connecting the top R of the second incident surface and the top T of the total reflection surface and the tangent line TU of the lower optical surface 73 at the intersection T of the lines satisfies the following condition: 60°<∠RTU<120°.

[0069] The light 711 that would otherwise form stray light 32 and enters the lens body from the top of the lens cavity and cannot be totally reflected out is totally reflected by the upper optical surface 71 and the side surface 73, and then passes through the lens from the position where the curved lower optical surface 72 first extends downward, and will no longer be totally reflected out from the top of the lens, as shown in light path 712.

[0070] As can be seen from the structure of the extension portion shown in the figure, the extension portion is connected to the outer ends of the total reflection surface and the second exit surface, has a certain thickness, and makes a certain transition in the upper and lower directions between the ends of the total reflection surface and the second exit surface. The end of the second exit surface covers the end of the total reflection surface outward in the horizontal direction. At the same time, as an integrally molded part of the lens body, stray light at an appropriate angle can be directly projected to the extension portion within the lens body. As a structural edge, the extension portion has other conventional uses of a structural edge.

[0071] Extended Example 4:

[0072] like Figure 12 and Figure 13 As shown, this embodiment, as an additional characteristic structure, can be superimposed on any of the aforementioned embodiments to form a new embodiment. Figure 12 and Figure 13 Only a partial schematic diagram of the additional characteristic structure is shown, and the complete lens structure is not shown, because it can serve as an additional characteristic structure. The additional characteristic structure is:

[0073] An extension portion is provided at the outer edge of the periphery of the lens body connecting the total reflection surface and the second emitting surface. The extension portion includes an upper optical surface 81 extending along the horizontal plane, a vertical side surface 83 and a lower optical surface 82. The lower optical surface is a curved surface that first extends downward and then pulls upward.

[0074] The angle formed by the line RT connecting the top R of the second incident surface and the top T of the total reflection surface and the tangent line TU of the lower optical surface 83 at the intersection T of the lines satisfies the following condition: 60°<∠RTU<120°.

[0075] The light 811 that would otherwise form stray light and enter the lens body from the top of the lens cavity cannot be fully reflected and emitted. After being fully reflected by the upper optical surface 81 and the side surface 83, it passes through the lens from the position where the curved lower optical surface 82 extends downward, and will no longer be fully reflected from the top of the lens, as shown in light path 812.

[0076] As can be seen from the structure of the extension portion shown in the figure, the extension portion is connected to the outer ends of the total reflection surface and the second exit surface, has a certain thickness, and makes a certain transition in the upper and lower directions between the ends of the total reflection surface and the second exit surface. The end of the second exit surface covers the end of the total reflection surface outward in the horizontal direction. At the same time, as an integrally molded part of the lens body, stray light at an appropriate angle can be directly projected to the extension portion within the lens body. As a structural edge, the extension portion has other conventional uses of a structural edge.

[0077] It can be seen that the difference between this embodiment and embodiment 3 lies in the second incident surface being a conventional incident surface.

[0078] Other structures of this embodiment are not limited to those shown in the figures. The additional extension structure can be applied to the combination of various basic structures, and can also be considered to be set up separately.

[0079] Based on the disclosure and teachings of the above description, those skilled in the art may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and any modifications and variations of the invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience of description only and do not constitute any limitation to the invention.

Claims

1. A collimating lens for eliminating stray light, comprising a lens body rotationally symmetrical about a central optical axis, a concave cavity with an opening facing a light source provided at the lower end of the body, the top of the concave cavity forming a first incident surface, and an annular side surface of the concave cavity forming a second incident surface; a first exit surface located in the middle corresponding to the first incident surface, and a second exit surface located on the circumferential side of the first exit surface corresponding to the second incident surface provided at the upper end of the body, the circumferential side surface of the body forming a total reflection surface facing the second exit surface; small-angle light emitted by the light source enters the lens body from the first incident surface and is collimatedly emitted from the first exit surface; large-angle light emitted by the light source is refracted from the second incident surface into the lens body and is emitted to the total reflection surface, which is then reflected to the second exit surface and collimatedly emitted; Its characteristics are: The slope of each point on the incident curve intercepted by the second incident surface and the plane passing through the optical axis is negative. As the incident curve extends from the bottom to the top, the absolute value of the slope first gradually decreases to the first inflection point and then gradually increases; The angle between the line connecting the first inflection point and the center of the light source and the optical axis is not less than 50 degrees and not more than 65 degrees; The slope of the emission curve intercepted by the second emission surface and the plane passing through the optical axis is positive, and in the process of extending from the inside to the outside to the edge, the slope first gradually increases to the second inflection point and then gradually decreases; The ratio of the diameter D of the outer edge of the second exit surface to the height difference H between the edge of the second exit surface and the center of the light source satisfies: 0.45 <H / D<0.65; The ratio of the diameter d of the circle formed by the second inflection point of each emission curve along the circumferential direction to the diameter D of the outer peripheral edge of the second emission surface satisfies: 0.65 <d / D<0.85; The emission curve extends from the middle to the edge, and the slopes of the starting point closest to the middle and the end point closest to the edge are both no greater than 2.

7.

2. The collimating lens according to claim 1, wherein The angle between the line connecting the top of the incident curve and the center of the light source and the optical axis is greater than 25 degrees and less than 45 degrees; the angle between the line connecting the bottom of the incident curve and the center of the light source and the optical axis is greater than 75 degrees and less than 90 degrees; the absolute value of the slope of the starting point of the bottom end of the incident curve is not less than 6.

3. The collimating lens according to claim 1, wherein: The first incident surface is a curved surface convex toward the light source; the first exit surface is a curved surface convex away from the light source, and the height difference dh between the highest point and the lowest point of the convex curved surface is proportional to the aperture d1 of the outer edge of the first exit surface and satisfies the following relationship: dh / d1<0.

35.

4. The collimating lens according to claim 1, wherein: The slope of the edge point of the section obtained by the intersection of the first incident surface and the plane passing through the optical axis is not less than 0.

2.

5. The collimating lens according to claim 1, wherein: An extension portion is provided on the outer edge of the periphery of the lens body connecting the total reflection surface and the second exit surface. The extension portion includes a planar extended upper optical surface, a vertical side surface and a lower optical surface. The lower optical surface is a curved surface that first extends downward and then pulls upward.

6. The collimating lens according to claim 5, wherein: The angle formed by the line connecting the top of the second incident surface and the top of the total reflection surface and the tangent line of the lower optical surface at the intersection of the lines satisfies the following conditions: The angle is greater than 60° and less than 120°.

7. The collimating lens according to claim 1, wherein: One or more curved surfaces among the first incident surface, the first exit surface and the second exit surface are provided with a bead-shaped microstructure; the second incident surface and / or the total reflection surface are scaly microstructure surfaces.

Images