TWI694290B - Lens and illumination device - Google Patents

Abstract

A lens is adapted to an illumination device. A first surface is depressed on a bottom of the lens and a second surface is depressed on the top of the lens. Providing a reference point on the bottom, and providing a horizontal axis and a vertical axis running through the reference point, an imaginary plane is defined by the horizontal axis and the vertical axis. A projection of the first surface on the imaginary plane includes a first, a second, a third and a fourth line segments sequentially connected. A direction from the reference point to a first corner point of the first and second line segments and the horizontal axis form a first reference angle, and the first reference angle is smaller than 15 degrees. A direction from the reference point to a second corner point of the second and third line segments and the horizontal axis form a second reference angle, and the first reference angle is between 2 to 40 degrees. A direction from the reference point to a third corner point of the third and fourth line segments and the horizontal axis form a third reference angle, and the third reference angle is between 20 to 88 degrees.

Description

Lens and light emitting device

The invention relates to a backlight device, in particular to a lens for a backlight and a light-emitting device with a lens.

In a direct type backlight module using a point light source (such as an LED) as a backlight source, in order to distribute the light intensity uniformly, a point light source with a smaller size is usually arranged on the substrate in an array. The point light sources must be arranged smaller to avoid the formation of obvious bright/dark areas between the point light sources.

If the configuration of high-power point light sources is used to reduce the number of point light sources, the light shape of each light source needs to be additionally processed with a lens, so that the light can be converted into side light after passing through the lens.

Existing lenses include refractive and reflective types. In the refraction type, after the light incident surface and the light exit surface are subjected to secondary refraction, they are turned to side light. In the reflection type, a reflection structure is added between the second refractions, so that before the second refraction, the direction of the light is changed to the lateral direction by the reflection structure, and then the direction is adjusted through the second refraction.

Existing refractive or reflective lenses still have a considerable degree of forward light leakage or back light leakage. Whether it is forward light leakage or back light leakage, a bright area will be formed above the point light source. Therefore, the actual configuration will still form a light source array with a small size, low power, but a large number of point light sources, so that the aforementioned bright areas are not too obvious.

The invention provides a lens and a light-emitting device, which can improve the light shape, reduce the forward and backward light leakage, and reduce the full width at half maximum (FWHM) range.

At least one embodiment of the present invention provides a lens including a bottom and a top opposite to each other; a first surface is recessed at the bottom, a second surface is recessed at the top, and a third surface connects the edges of the bottom and the top; at the bottom Define a reference point, and define a horizontal axis and a vertical axis passing through the reference point, the horizontal axis is parallel to the bottom, the vertical axis is perpendicular to the bottom, and the horizontal axis and the vertical axis define an imaginary plane.

Wherein, the projection of the first surface on the imaginary plane is a first line segment, a second line segment, a third line segment and a fourth line segment connected in sequence, the first line segment extends from the horizontal axis, and the fourth line segment is connected to Vertical axis, the first line segment and the second line segment are connected to a first turning point, the second line segment and the third line segment are connected to a second turning point, the third line segment and the fourth line segment are connected to a third turning point; the first line segment , The second line segment, the third line segment, and the fourth line segment satisfy the following relationship: the direction from the reference point to the first turning point forms a first reference angle with the horizontal axis, and the angle of the first reference angle is less than 15 degrees; the reference point to The direction of the second turning point forms a second reference angle with the horizontal axis, and the angle of the second reference angle is between 2 degrees and 40 degrees; and the direction of the reference point to the third turning point forms a first angle with the horizontal axis Three reference angles, the angle of the third reference angle is between 20 degrees and 88 degrees.

In at least one embodiment of the present invention, the first reference angle is less than 5 degrees, the second reference angle is between 5 degrees and 30 degrees, and the third reference angle is between 30 degrees and 85 degrees.

In at least one embodiment of the present invention, the direction from the reference point to an outer periphery of the second surface forms a fourth reference angle with the horizontal axis, and the angle difference between the fourth reference angle and the second reference angle is between Between plus and minus 10 degrees.

In at least one embodiment of the invention, the angle difference is zero.

In at least one embodiment of the present invention, the average slope of the second line segment is less than the average slope of the first line segment, the average slope of the third line segment is greater than the average slope of the second line segment, and the average slope of the fourth line segment is less than that of the third line segment Average slope.

In at least one embodiment of the present invention, the first line segment is a curve or a straight line, the second line segment is a straight line or a curve, the third line segment is a straight line or a curve, and the fourth line segment is a straight line.

In at least one embodiment of the present invention, the first surface has an upper vertex, and the second surface has a lower vertex. The upper vertex and the lower vertex are respectively located on the vertical axis and maintain a separation distance.

In at least one embodiment of the present invention, the vertical axis is used as the axis of symmetry, and the first surface is projected on the imaginary plane to form another set of line segments, which are axisymmetric with the first line segment, the second line segment, the third line segment, and the fourth line segment. And two sets of line segments are connected at the top vertex.

In at least one embodiment of the present invention, the first surface and the second surface are symmetrical in radiation according to the vertical axis.

In at least one embodiment of the present invention, a longitudinal axis perpendicular to the vertical axis and the horizontal axis is defined, and the first surface exhibits a long groove shape and is an axis-symmetrical shape based on the longitudinal axis.

In at least one embodiment of the present invention, the reference point is used as the origin of a standard, and the first turning point, the second turning point, and the third turning point have a standard value relationship between the horizontal axis and the vertical axis, The coordinate value of the vertical axis is equal to m times the coordinate value of the horizontal axis, and the m value of the first turning point is 0.03~0.13, the m value of the second turning point is 0.17~0.87, and the m value of the third turning point is 1.7~8.51.

At least one embodiment of the present invention further provides a light-emitting device including a substrate, a light source, and the lens as described above. The substrate has an upper surface; the light source is disposed on the upper surface of the substrate; the bottom of the lens is fixed to the substrate, covers the light source, and is located at the reference point.

In the lens and the light emitting device of the present invention, the first surface of the incident light is curved surfaces with different average curvatures from the outer edge to the center (corresponding to the first line segment, the second line segment, the third line segment and the fourth line segment) ) Receive light and refract it to process light entering at different reference angles. Therefore, the light rays entering the light at different reference angles can be refracted a second time with or without reflection, and concentrated on the side light. Therefore, the present invention can effectively reduce the intensity of forward light leakage or backward light leakage, and achieve a good light shape.

1: Light emitting device

100: substrate

110: upper surface

200: light source

300: lens

310: bottom

320: top

S1: first surface

S2: Second surface

S3: third surface

Ref: reference point

X: horizontal axis

Y: vertical axis

UP: upper vertex

DP: lower vertex

C1: The first line segment

C2: Second line segment

C3: The third line segment

C4: Fourth line segment

CP1: the first turning point

CP2: second turning point

CP3: third turning point

θ 1: first reference angle

θ 2: second reference angle

θ 3: third reference angle

θ 4: fourth reference angle

Z: longitudinal axis

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG. 1.

3 is a partial cross-sectional schematic diagram of an embodiment of the present invention.

4 is another schematic cross-sectional view of an embodiment of the present invention.

5 is a perspective view of an embodiment of the present invention.

6 is another partial cross-sectional schematic diagram of an embodiment of the present invention.

7 is a light distribution curve diagram of an embodiment of the present invention.

8 is a perspective view of a partial structure in another embodiment of the present invention.

In the drawings, for the sake of clarity, the widths of some elements, regions, etc. are enlarged. Throughout the specification, the same element symbol indicates the same element. It should be understood that when an element such as an element is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present.

It should be understood that although the terms "first", "second", "third", etc. may be used throughout the specification to describe various elements, components, regions, or parts. However, these elements, components, regions, and/or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, or section from another element, component, region, layer, or section. Therefore, the "first element", "component", "region" or "portion" discussed below may be referred to as a second element, component, region or section without departing from the teachings herein.

In addition, relative terms such as "lower" or "bottom plate" and "upper" or "top surface" may be used herein to describe the relationship between one element and another element, as shown. It should be understood that relative terms are intended to include different orientations of the device than those shown in the figures. For example, if the device in a drawing is turned over, the element described as being on the "lower" side of the other element will be oriented on the "upper" side of the other element. Therefore, the exemplary term "down" may include the orientations of "down" and "up", depending on the specific orientation of the drawing.

Please refer to FIGS. 1 and 2, which is a light-emitting device 1 disclosed in the embodiment of the present invention, which includes a substrate 100, a light source 200 and a lens 300.

As shown in FIGS. 1 and 2, the substrate 100 is used as a base for installation, for the light source 200 and the lens 300 to be installed thereon. The substrate 100 also provides necessary circuits (not shown) to supply driving power to the light source 200. In addition, the upper surface 110 of the substrate 100 may also be provided with necessary optical structures to reflect or diffuse light. For example, a white reflective sheet is disposed on the upper surface 110, and a diffusion plate is provided above the substrate 100.

As shown in FIGS. 1 and 2, the light source 200 is disposed on the upper surface 110 of the substrate 100 and emits light on the upper surface 110. The light source 200 is in the form of point light emission, which may be, but not limited to, a light emitting diode. The direction of the light emitted by the light source 200 ranges directly from the normal of the upper surface 110 to a direction nearly parallel to the upper surface 110; that is to say, the direction of the light emitted by the light source 200 includes forward light emission and side light emission.

As shown in FIGS. 1, 2 and 3, the lens 300 has a double refraction function. When the light enters the lens 300, the light is refracted for the first time, and when the light leaves the lens 300, it is refracted for the second time.

As shown in FIGS. 1, 2 and 3, the lens 300 has a bottom 310 and a top 320 opposite to each other. The bottom 310 is fixed to the substrate 100 and covers the light source 200. The bottom 310 is concavely provided with a first surface S1, the top 320 is concavely provided with a second surface S2, and the edges of the bottom 310 and the top 320 are connected by a third surface S3, so that the third surface S3 surrounds the side of the lens 300. The lens 300 is made of a material with good light transmission properties. The aforementioned materials include but are not limited to PMMA (acrylic), PC (polycarbonate), or PS (polystyrene). CNC cutting and forming.

As shown in FIGS. 1, 2 and 3, the first surface S1 defines an accommodation space, and the light source 200 is located in the accommodation space. The light emitted by the light source 200 enters the lens from the first surface S1 300, with or without reflection through the second surface S2, and emit light toward the third surface S3, so that the light emitted by the light source 200 is guided to the side light of the lens 300, and a uniform shape is formed on the upper surface 110 of the substrate 100 Brightness distribution.

As shown in FIG. 3, a reference point Ref is defined at the bottom 310, and a horizontal axis X and a vertical axis Y passing through the reference point Ref are defined. The horizontal axis X is parallel to the bottom 310, and the vertical axis Y is perpendicular to the bottom 310 and horizontal The axis X and the vertical axis Y can define an imaginary plane XY. The light source 200 is located at the reference point Ref, an upper vertex UP of the first surface S1 and a lower vertex DP of the second surface S2 are respectively located at the vertical axis Y, and maintain a separation distance.

As shown in FIG. 3, the first surface S1 is projected into a first line segment C1, a second line segment C2, a third line segment C3, and a fourth line segment C4 on the virtual plane XY. The first line segment C1, the second line segment C2, the third line segment C3, and the fourth line segment C4 are sequentially connected. The first line segment C1 extends from the horizontal axis X, and the fourth line segment C4 is connected to the vertical axis Y and the upper vertex UP. The first line segment C1 and the second line segment C2 are connected to a first turning point CP1, the second line segment C2 and the third line segment C3 are connected to a second turning point CP2, and the third line segment C3 and the fourth line segment C4 are connected to a third turning point CP3, and the fourth line segment C4 and the vertical axis Y are connected to the upper vertex UP.

With reference to FIGS. 2 and 3, with the vertical axis Y as the axis of symmetry, the first surface S1 is projected on the imaginary plane XY to form another set of line segments, along with the first line segment C1, the second line segment C2, the third line segment C3, and the fourth The line segment C4 is axisymmetric, and the two sets of line segments are connected at the upper vertex UP.

As shown in FIGS. 3 and 4, the aforementioned first line segment C1, second line segment C2, third line segment C3, and fourth line segment C4 satisfy the following relationship, so that the light emitted by the light source 200 enters the light from the first surface S1, Light exits towards the third surface S3, reducing transmission through the second surface S2 from the top 320 light output. In FIG. 3 and FIG. 4, broken lines represent light rays, and hatching lines representing the solid parts of the lens 300 are omitted, so that the drawings can be presented concisely.

As shown in FIGS. 3 and 4, the direction from the reference point Ref to the first turning point CP1 forms a first reference angle θ 1 with the horizontal axis X, and the angle of the first reference angle θ 1 is less than 15 degrees (θ 1< 15°), preferably less than 5 degrees (θ 1<5°). The first line segment C1 may be a curve or a straight line. When the first line segment C1 is a straight line, the first line segment C1 may be parallel to the vertical axis Y, that is, perpendicular to the horizontal axis X. The portion of the first surface S1 corresponding to the first line segment C1 is used to process light with a small elevation angle, so that the light passes through the third surface S3 toward the lens 300 side in a direction closer to the horizontal (parallel to the horizontal axis X) To the light.

As shown in FIGS. 3 and 4, the direction from the reference point Ref to the second turning point CP2 forms a second reference angle θ 2 with the horizontal axis X, and the angle of the second reference angle θ 2 is between 2 degrees and 40 degrees (2°≦θ 2≦40°), preferably between 5 degrees and 30 degrees (5°≦θ 2≦30°); the lower limit of the aforementioned second reference angle θ 2 mainly depends on the first reference For the set value of the angle θ1, the second reference angle θ2 needs to be greater than the first reference angle θ1. The second line segment C2 may also be a curve or a straight line, and the average slope of the second line segment C2 is smaller than the average slope of the first line segment C1. The portion of the first surface S1 corresponding to the second line segment C2 is used to process light with a slightly larger light elevation angle so that the light enters the second surface S2 at a larger angle of incidence and is totally reflected by the second surface S2 to approach After being horizontal, the light is emitted toward the side of the lens 300 via the third surface S3.

As shown in FIGS. 3 and 4, the direction from the reference point Ref to the third turning point CP3 forms a third reference angle θ 3 with the horizontal axis X. The angle of the third reference angle θ 3 is between 20 degrees and 88 degrees (20°≦θ 3≦88°), preferably between 30 degrees and 85 degrees (30°≦θ 3≦85°); the lower limit of the aforementioned third reference angle θ 3 mainly depends on the second reference Set value of angle θ 2, third reference angle θ 3 needs to be greater than the second reference angle θ 2. The third line segment C3 is a curve, and the average slope of the third line segment C3 is greater than the average slope of the second line segment C2. The portion of the first surface S1 corresponding to the third line segment C3 is used to process light with a larger light elevation angle, so that the light can enter the second surface S2 at a larger angle of incidence and be totally reflected by the second surface S2 to approach After being horizontal, the light is emitted toward the lens 300 through the third surface S3.

As shown in FIGS. 3 and 4, the portion of the first surface S1 from the third turning point CP3 to the upper vertex UP is the fourth line segment C4, and the part of the fourth line segment C4 is used for incident light with an elevation angle close to 90 degrees, and After refraction with a larger amplitude and being totally reflected by the second surface S2 to be close to horizontal, the light is emitted toward the lens 300 side through the third surface S3. The fourth line segment C4 is a straight line, and the average slope is smaller than the average slope of the third line segment C3. The fourth line segment C4 is a straight line, which is beneficial to processing, and avoids the influence of the upper vertex UP and the fourth line segment C4 on the optical performance due to processing tolerances.

In addition, regarding the relative relationship between the first surface S1 and the second surface S2, a direction from the reference point Ref to the outer periphery of the second surface S2 forms a fourth reference angle θ 4 with the horizontal axis X. The angle difference between the fourth reference angle θ 4 and the second reference angle θ 2 is between plus and minus 10 degrees, preferably the fourth reference angle θ 4 is equal to the second reference angle θ 2, that is, the angle difference is zero .

As shown in FIG. 5, the first surface S1 and the second surface S2 can be based on the vertical axis Y as a radial symmetry pattern, that is, based on the vertical axis Y, any imaginary plane XY including the vertical axis Y can be used. Two sets of the first line segment C1, the second line segment C2, the third line segment C3, and the fourth line segment C4 that are axisymmetric with each other according to the vertical axis Y are obtained. In other words, both the first surface S1 and the second surface S2 exhibit a concave conical hole pattern, and the sharp points of the two conical holes, that is, the upper vertex UP and the lower vertex DP as shown in FIG. 3 are located on the vertical axis On Y, and separated by a separation distance and not connected.

The following is a further example. The lens 300 is of a radial symmetry type, the top 320 and the bottom 310 are circular, and the diameter of the top 320 is 30 m, and the diameter of the bottom 310 is 26 mm; the height of the lens 300 is 8 mm. Taking the reference point Ref as the coordinate origin, the relative relationship between each line segment and each turning point on the horizontal axis X and the vertical axis Y is shown in Table 1.

As shown in Table 1, one end of the first line segment C1 is located on the horizontal axis X, the coordinate value is (3.50,0), and the other end is the first turning point CP1, the coordinate value is (3.50,0.20), the first line segment C1 The slope of is infinite (set the first line segment C1 as a straight line), that is, the first line segment C1 is parallel to the vertical axis Y and perpendicular to the horizontal axis X. At this time, the angle of the first reference angle θ 1 is about 3.3 degrees, which falls within a range of less than 15 degrees or less than 5 degrees. At this time, the relative angle of the first line segment C1 with respect to the horizontal axis X is 90 degrees.

As shown in Table 1, one end of the second line segment C2 is connected to the first line segment C1 by the first turning point CP1, and the other end is the second turning point CP2, and the coordinate value of the second turning point CP2 is (1.50, 0.60). The slope of the second line segment C2 is 0.20 (the second line segment C2 is set as a straight line), that is, the change trend of the slope from the first line segment C1 to the second line segment C2 is decreasing. At this time, the second reference angle θ 2 The angle is about 21.8 degrees, which falls within the range of 2 degrees to 40 degrees or 5 degrees to 30 degrees. The relative angle of the second line segment C2 with respect to the horizontal axis X is 11.3 degrees.

As shown in Table 1, one end of the third line segment C3 is connected to the second line segment C2 by the second turning point CP2, and the other end is the third turning point CP3. The coordinate value of the third turning point CP3 is (0.54, 1.40). The slope of the third line segment C3 is 0.83 (the third line segment C3 is set as a straight line), that is, the change trend of the slope from the second line segment C2 to the third line segment C3 is increasing. At this time, the angle of the third reference angle θ 3 is approximately 68.9 degrees, which falls within the range of 20 degrees to 88 degrees or 30 degrees to 85 degrees. The relative angle of the third line segment C3 with respect to the horizontal axis X is 39.8 degrees.

As shown in Table 1, one end of the fourth line segment C4 is connected to the third line segment C3 with the third turning point CP3, and the other end is the upper vertex UP, and the coordinate value of the upper vertex UP is (0.00, 1.70). The slope of the fourth line segment C4 is 0.56 (the fourth line segment C4 is set as a straight line), that is, the slope change trend from the third line segment C3 to the fourth line segment C4 is reduced. At this time, the relative angle of the fourth line segment C4 with respect to the horizontal axis X is 29.1 degrees.

The aforementioned dimensions and relative positional relationships are only examples and are not intended to limit the specific implementation of the present invention. From the comparison in Table 1 and the foregoing description, it can be seen that the slope change trends of the first line segment C1, the second line segment C2, the third line segment C3, and the fourth line segment C4 are to decrease, increase, and decrease to ensure the light with different angles of elevation , Can be refracted by the first surface S1 to a horizontal direction, and directly emit light through the third surface S3, or fall on the second surface S2 at a large angle and be totally reflected by the second surface S2 to the third surface S3 . The curvature configuration of the second surface S2 is mainly matched with the second line segment C2, the third line segment C3 and the fourth line segment C4, so that the light refracted and projected onto the second surface S2 can be totally reflected to the horizontal direction, reducing the transmission through the top 320 positive light leakage.

As shown in Table 2 and FIG. 6, the reference point Ref is used as the coordinate origin, and the relationship between the coordinate values of each turning point on the horizontal axis X and the vertical axis Y can also be expressed by Y=mX. That is, the coordinate value on the vertical axis Y satisfies m times the coordinate value of the horizontal axis X. The first turning point CP1, the second turning point CP2, and the third turning point CP3 have different ranges of m values, respectively. As shown in Table 2, in the coordinate value of the first turning point CP1, the ratio of m=Y/X can be 0.03~0.13, and the corresponding first reference angle θ 1 ranges from 0.15 degrees to 7.48 degrees; the coordinate of the second turning point CP2 In the value, the ratio of m=Y/X can be 0.17~0.87, and the corresponding second reference angle θ 2 ranges from 9.83 degrees to 40.89 degrees; in the coordinate value of the third turning point CP3, the ratio of m=Y/X can be 1.7~8.51, the corresponding third reference angle θ 3 ranges from 59.55 degrees to 83.30 degrees.

As shown in FIG. 7, the light distribution of the light-emitting device 1 to which the lens 300 is applied is arranged through the first surface S1 described above. The angle marked in FIG. 7 is the angle between the light exit direction and the positive direction, that is, the angle between the light exit direction and the vertical axis Y. It can be seen from the figure that the full width at half maximum (FWHM) of the light emitted by the lens 300 is concentrated at 90 degrees, and the half intensity angle of the light falls within the range of 14 degrees, that is, the light output is concentrated to the side, and There is a small positive light leakage. In addition, the aforementioned peak half-angle of light emission also falls below 90 degrees, thereby reducing back light leakage. Therefore, regardless of It is the forward or backward direction of the light source 200 (close to 0 degrees or greater than 90 degrees), and the light intensity is relatively low without obvious noise, which can effectively alleviate the problem of over-brightness above the light source 200.

As shown in FIG. 8, the structure of the lens 300 does not limit the radiation symmetry pattern. Define a longitudinal axis Z perpendicular to the vertical axis Y and the horizontal axis X, the projection of the first surface S1 on the XZ plane presents an almost elliptical or olive shape, in other words, the first surface S1 presents a long groove shape Rather than forming a radial symmetric cone hole based on the vertical axis Y, it is an axis symmetrical pattern based on the longitudinal axis Z.

In the lens 300 and the light-emitting device 1 of the present invention, the incident first surface S1 has curved surfaces with different average curvatures from the outer edge to the center (corresponding to the first line segment C1, the second line segment C2, and the third line segment C3 and part C4 of the fourth line segment) receive light and refract it to process light entering at different reference angles. Therefore, the light rays entering the light at different reference angles can be refracted a second time with or without reflection, and concentrated on the side light. Therefore, the present invention can effectively reduce the intensity of forward light leakage or backward light leakage, and achieve a good light shape.

300: lens

S1: first surface

S2: Second surface

Ref: reference point

X: horizontal axis

Y: vertical axis

UP: upper vertex

DP: lower vertex

C1: The first line segment

C2: Second line segment

C3: The third line segment

C4: Fourth line segment

CP1: the first turning point

CP2: second turning point

CP3: third turning point

θ 1: first reference angle

θ 2: second reference angle

θ 3: third reference angle

Claims (12)

A lens includes: a bottom and a top opposite to each other; the bottom is concavely provided with a first surface, the top is concavely provided with a second surface, and the edges of the bottom and the top are connected by a third surface; defined at the bottom A reference point, and defining a horizontal axis and a vertical axis passing through the reference point, the horizontal axis is parallel to the bottom, the vertical axis is perpendicular to the bottom, and the horizontal axis and the vertical axis define an imaginary plane; wherein, The first surface is projected on the imaginary plane as a first line segment, a second line segment, a third line segment, and a fourth line segment connected in sequence, the first line segment extends from the horizontal axis, and the fourth The line segment is connected to the vertical axis, the first line segment and the second line segment are connected to a first turning point, the second line segment and the third line segment are connected to a second turning point, and the third line segment is connected to the fourth line segment At a third turning point; the first line segment, the second line segment, the third line segment and the fourth line segment satisfy the following relationship: the direction from the reference point to the first turning point forms a first line with the horizontal axis A reference angle, the angle of the first reference angle is less than 15 degrees; the direction from the reference point to the second turning point forms a second reference angle with the horizontal axis, and the angle of the second reference angle is between 2 degrees To 40 degrees; and the direction from the reference point to the third turning point forms a third reference angle with the horizontal axis, and the angle of the third reference angle is between 20 degrees and 88 degrees. The lens of claim 1, wherein the first reference angle is less than 5 degrees, the second reference angle is between 5 degrees and 30 degrees, and the third reference angle is between 30 degrees and 85 degrees. The lens according to claim 1, wherein the direction from the reference point to an outer periphery of the second surface forms a fourth reference angle with the horizontal axis, the fourth reference angle and the second reference angle The difference in angle is between plus and minus 10 degrees. The lens according to claim 3, wherein the angle difference is zero. The lens according to claim 1, wherein the average slope of the second line segment is smaller than the average slope of the first line segment, the average slope of the third line segment is greater than the average slope of the second line segment, and the average of the fourth line segment The slope is less than the average slope of the third line segment. The lens according to claim 1, wherein the first line segment is a curve or a straight line, the second line segment is a straight line or a curve, the third line segment is a straight line or a curve, and the fourth line segment is a straight line. The lens according to claim 1, wherein the first surface has an upper vertex and the second surface has a lower vertex, and the upper vertex and the lower vertex are respectively located on the vertical axis and maintain a separation distance. The lens according to claim 7, wherein, with the vertical axis as the axis of symmetry, the first surface is projected on the imaginary plane to form another set of line segments, and the first line segment, the second line segment, and the third line segment And the fourth line segment is axisymmetric, and the two sets of line segments are connected at the upper vertex. The lens according to claim 7, wherein the first surface and the second surface are of a radiation symmetry pattern based on the vertical axis. The lens according to claim 7, wherein a longitudinal axis perpendicular to the vertical axis and the horizontal axis is defined, the first surface exhibits a long groove shape, and is an axisymmetric shape based on the longitudinal axis. The lens according to claim 1, wherein the reference point is used as a standard origin, and a standard value relationship between the first turning point, the second turning point, and the third turning point on the horizontal axis and the vertical axis is: The coordinate value of the vertical axis is equal to m times the coordinate value of the horizontal axis, and the m value of the first turning point is 0.03~0.13, the m value of the second turning point is 0.17~0.87, and the m value of the third turning point It is 1.7~8.51. A light-emitting device comprising: a substrate having an upper surface; a light source provided on the upper surface of the substrate; and the lens according to any one of claim 1 to claim 11, wherein the bottom of the lens It is fixed to the substrate, covers the light source, and is located at the reference point.

Images