TWI708911B - Light emitting device - Google Patents

Abstract

A light emitting device having a circuit board, a light source, at least one reflective element and an optical element is provided. The light source is disposed on the circuit board. The at least one reflective element is disposed adjacent to the light source and includes a reflective surface. The optical element is disposed above the light source and the at least one reflective element, and includes a light transmissive element and an interference element. The interference element is arranged to have a destructive interference direction, and a horizontal extension direction of the reflection surface is not parallel to the destructive interference direction, such that the light emitted from the light transmissive element becomes a plurality of juxtaposed thin and narrow light patterns.

Description

Light-emitting device

The present invention relates to a light-emitting device, and more particularly to a light-emitting device that generates a plurality of parallel narrow light-emitting devices.

With the advancement of technology and market demand, many existing taillights of mobile vehicles (cars, locomotives, etc.) tend to use light-emitting diodes (LEDs) as light sources to improve the lack of traditional halogen lamps or xenon lamps . However, the LED itself is a point light source with relatively divergent light, and the light pattern it presents is roughly a circular halo (as shown in Figure 1), with a bright area 1 with strong brightness in the center, and gradually decreasing brightness from the surroundings. The formation of dark zone 2. Even if multiple LEDs can be arranged in various shapes, they still show multiple circular halos 3 (as shown in Figure 2). This type of light pattern has been difficult to meet the diverse needs of the automotive industry for optical effects. Especially the pursuit of personalization for high-end vehicles. In addition, if LEDs are simply used to achieve variable light patterns, the required quantity will not only increase material, manufacturing and maintenance costs, but also constrained by the dense LED arrangement, the installation of the reflector is more difficult, which will make the light emitting angle and light pattern effect Subject to great restrictions.

In view of this, how to provide a light-emitting device to improve the above-mentioned shortcomings is a problem to be solved in the industry.

An object of the present invention is to provide a light-emitting device which can emit a plurality of parallel narrow light types.

To achieve the above objective, the light-emitting device of the present invention includes a circuit substrate, a light source, at least one reflective element and an optical element. The light source is arranged on the circuit substrate, and at least one reflective element is adjacent to the light source And includes a reflective surface. The optical element includes a light transmitting element and an interference element, and the interference element is arranged under the light transmitting element. At least one reflective element and optical element are located on a path of a light emitted by the light source, so that the light is reflected by the at least one reflective element and then emitted from the light-transmitting element through the interference element. The interference element is arranged to have a destructive interference direction, and an extension direction of the reflecting surface is not parallel to the destructive interference direction, so that the light emitted from the light-transmitting element generates a plurality of parallel narrow light patterns.

In one embodiment, the at least one reflective element of the light-emitting device of the present invention includes two reflective elements symmetrically adjacent to two opposite sides of the light source, or four reflective elements equally spaced adjacent to the light source.

In one embodiment, the reflective surface of the light emitting device of the present invention is flat in a direction away from the light source.

In one embodiment, the reflective surface of the light emitting device of the present invention is curved in a direction away from the light source.

In one embodiment, the rear side of the reflective surface of the light-emitting device of the present invention has an angle with respect to the circuit board, and the angle is not less than half of the supplementary angle of the light source.

In one embodiment, there is a shortest linear distance between the reflective surface of the light-emitting device of the present invention and the light source, which is not more than 1 cm or not more than 6 mm.

In one embodiment, the at least one reflective element of the light-emitting device of the present invention is at least one body or at least one plate.

In one embodiment, at least one reflective element of the light-emitting device of the present invention is disposed on the circuit substrate.

In order to make the above objectives, technical features and advantages more obvious and understandable, the following is a detailed description with preferred embodiments in conjunction with the accompanying drawings.

1‧‧‧Bright area

2‧‧‧Dark Zone

3‧‧‧Circular halo

10‧‧‧Light-emitting device

100‧‧‧Circuit board

200‧‧‧Light source

300‧‧‧Reflective element

400‧‧‧Optical components

410‧‧‧Transparent element

420‧‧‧Interference element

A1, A2‧‧‧angle

D1‧‧‧First direction

D2‧‧‧Second direction

D3‧‧‧Extending direction

L‧‧‧Light

RL‧‧‧reflected light

H‧‧‧Narrow light type

H1, H2, H3‧‧‧Light type

S‧‧‧The shortest straight line distance

F‧‧‧Horizontal component

Figure 1 is a schematic diagram of the light pattern of the LED light source in the prior art;

Figure 2 is a schematic diagram of an arrangement pattern of LED light sources in the prior art;

Figure 3A is a perspective view of the light emitting device of the present invention;

Figure 3B is a schematic diagram of a light pattern provided by the present invention;

Figure 4 is another perspective view of the light emitting device of the present invention;

5 to 6 are schematic side views of the light-emitting device of the present invention with different reflective surfaces;

Figures 7A to 7D and Figure 8 are schematic side views of different setting angles of the reflective surface of the light-emitting device of the present invention;

9A to 9C are schematic side views showing different distances between the reflective surface and the light source in the light-emitting device of the present invention; and

10A to 10D, 11A, and 11B are schematic top views of different positions of the reflective element in the light-emitting device of the present invention.

The following description combines the drawings to illustrate some embodiments of the present invention in detail. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other. Unless clearly indicated otherwise in the context, the singular form "one" used herein also includes the plural form, and the stated orientation (such as front, back, top, bottom, sides, inside, outside, etc.) refers to relative orientation. It can be defined according to the use state of the light-emitting device, and does not indicate or imply that the light-emitting device needs to have a specific structure or operation, and it cannot be understood as a limitation of the present invention.

The light-emitting device of the present invention can be mainly used in various lighting modules, such as brake lights, direction lights, headlights, tail lights or atmosphere lights. Each component of the light-emitting device can be fixed by a bracket (not shown in the figure) in the lighting module, so as not to be displaced due to shaking of the vehicle. One of the characteristics of the light-emitting device is to transform the circular halo of the prior art into a narrow light type through the interference effect of the optical elements, so as to meet the diversified needs of the automotive industry for optical effects. For example, as shown in Figure 3A, when the light source in the light emitting device 10 When the arrangement direction of 200 is perpendicular to the first direction D1 of destructive interference, the independent narrow light-shaped bright areas formed on the optical element 400 by each light source 200 can be connected or overlapped to form a longer and uniform Narrow light type H. The content of each component is described in detail as follows.

Please refer to FIGS. 4 to 6, the light emitting device 10 includes a circuit substrate 100, a light source 200, at least one reflective element 300, and an optical element 400. The light source 200 is disposed on the circuit substrate 100 to receive power and emit light. The light source 200 can be any element that can emit light. The following embodiments take an LED light source emitting amber, orange or red as an example, but it is not limited thereto. The light L emitted by the light source 200 has a light emitting angle. The following embodiments take the light source 200 with a light emitting angle of 120 degrees as an example (the angle A1 shown in the figure indicates half of the light emitting angle), and for convenience of illustration, the following embodiments Only a single LED light source is displayed, and all the light L and the reflected light RL are only represented by a few dotted lines for understanding the light-emitting range, but it does not mean that the light L emitted by the light source 200 is only a number of light beams.

The light source 200 may be composed of at least one light emitting diode (LED) or at least one laser diode (LD). The light emitting diode can be white light, red light, blue light, green light, orange light, yellow light or amber light. If the light-emitting diode is white light, the light-emitting diode includes a blue light-emitting diode chip and a phosphor. The phosphor can be any combination of yellow phosphor, green phosphor and red phosphor. The yellow phosphor can be Y ₃ Al ₅ O ₁₂ : Ce ³⁺ (YAG for short) and (Sr, Ba) ₂ SiO ₄ ：Eu ²⁺ (Sr ²⁺ content is higher, Silicate for short), green phosphor can be Si _6-z Al _z O _z N _8-z ：Eu ²⁺ (β-SiAlON for short) and Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ (referred to as LuAG), the red phosphor can be CaAlSiN ₃ : Eu ²⁺ (referred to as CASN or 1113), Sr ₂ Si ₅ N ₈ : Eu ²⁺ (referred to as 258) and K ₂ SiF ₆ : Mn ⁴⁺ (KSF for short). If the light-emitting diode is red, blue, green, orange, yellow or amber light, the light-emitting diode includes a red, blue, green, orange, yellow or amber light-emitting diode Wafer. The laser diode (LD) can be white light, red light, blue light, green light, orange light, yellow light or amber light. If the laser diode is white light, the laser diode includes a blue laser diode chip and a phosphor. The fluorescent powder can be any combination of yellow fluorescent powder, green fluorescent powder and red fluorescent powder. The yellow fluorescent powder can be Y ₃ Al ₅ O ₁₂ : Ce ³⁺ (YAG for short) and (Sr, Ba) ₂ SiO ₄ ：Eu ²⁺ (Sr ²⁺ content is higher, Silicate for short), green phosphor can be Si _6-z Al _z O _z N _8-z ：Eu ²⁺ (β-SiAlON for short) and Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ (referred to as LuAG), the red phosphor can be CaAlSiN ₃ : Eu ²⁺ (referred to as CASN or 1113), Sr ₂ Si ₅ N ₈ : Eu ²⁺ (referred to as 258) and K ₂ SiF ₆ : Mn ⁴⁺ (KSF for short). If the laser diode is red, blue, green, orange, yellow or amber light, the laser diode includes a red, blue, green, orange, yellow or amber laser Diode wafer.

At least one reflective element 300 is disposed adjacent to the light source 200. The material of the reflective element 300 can include polymethylmethacrylate (PMMA), polycarbonate (PC), metal or glass, etc., and can be a metal film reflector, medium Membrane mirrors or other components that can reflect light. The surface structure of the reflective element 300 can be smooth, triangular, square or hexagonal. The external shape of the reflective element 300 can be a single body or a board, which can be arranged on the circuit substrate 100 or arranged around the light source 200 by a bracket (not shown) in the lighting module. The reflective element 300 has a reflective surface 310 located on the path of the light L to reflect the light L to form a reflected light RL, which is then irradiated to the optical element 400. The reflective surface 310 can be flat in a direction away from the light source 200 (as shown in Figure 5), or curved to increase the intensity of the reflected light RL (as shown in Figure 6); the reflective surface 310 can extend to contact the optical element 400 or only a short distance from the optical element 400 (not shown). Although the figure shows a light source with two reflective elements 300, more than two reflective elements 300 can be provided according to different requirements, and have different configurations to achieve different effects (detailed description is shown later) . The multiple reflective elements 300 are not connected, that is, the reflective surfaces 310 are not connected. In other words, compared to the traditional setting around the light source, the reflective bowl and the reflective cup that are arranged around the light source with the light source as the center can be To completely reflect the light emitted from the light source toward the side, the reflective element 300 of the present invention can be discontinuously disposed around the light source 200, and does not completely reflect the light L emitted from the light source toward the side, but only partially reflects the light L to achieve compliance The light type on demand.

Please refer to Figures 3A and 4, the optical element 400 can be installed between the lampshade and the light source 200 or directly on the lampshade by a bracket (not shown) in the lighting module. The main material can be made of polycarbonate. (UV-Polycarbonate), polyester fiber (Polyester), acrylic (Acrylic), UVT acrylic is formed, which includes a light-transmitting element 410 and an interference element 420. The light-transmitting element 410 may include a light-transmitting substrate and an optically transparent layer, and the interference element 420 may be disposed under the optically-transmissive layer, The material of the optically transparent layer can be the same as that of the transparent substrate. What's more, the optically transparent layer and the transparent substrate may be integrally formed, or in the manufacturing process, the optically transparent layer is formed on the transparent substrate. , And then form an interference element 420 on the optically transparent layer (the difference in the direction wording is due to the different placement direction). Optionally, the interference element 420 may be formed by mold manufacturing, sandblasting, chemical etching, embossing, or laser etching.

The light L emitted from the light source 200 is emitted from the light-transmitting element 410 through the interference element 420 to form a specific light pattern. In this embodiment, the interference element 420 can interfere with the light L emitted by the light source 200 while maintaining a light transmittance of, for example, more than 80%. The interference element 420 can cause the light L to experience destructive interference (also called offset interference) in a first direction D1 and constructive interference (also called enhanced interference) in a second direction D2 to change the light profile. In other words, when the light L does not experience interference, the light type is a circular halo as shown in Figure 1. When the light L undergoes interference, the light type range in the first direction D1 is reduced (destructive Interference), the light type range in the second direction D2 is expanded (constructive interference), thus forming a narrow light type H as shown in Figures 3A and 4.

The optical element can interfere with the light emitted by the light source to produce a specific asymmetric light pattern, and at the same time can maintain, for example, a light transmittance of more than 80%. The interference element has both constructive interference and destructive interference characteristics. It interferes with the light from the light source so that the light from multiple light sources is in the first polarization direction, that is, the D1 direction The upper cancellation interference means destructive interference, and the second polarization direction, ie, the enhanced interference in the D2 direction, means constructive interference. Therefore, in this way, the halo pattern can be transformed into a linear pattern. In order to describe the interference process more clearly, the following is described with reference to Figure 1 and Figure 3B. It can be seen from Figure 1 that the halo pattern can be divided into two areas, namely the dark area 2 at the periphery and the bright area 1 at the center. After the light emitted by the light source passes through the interference element, it has experienced constructive interference in different directions. It involves destructive interference. Therefore, the light in the D1 direction will undergo destructive interference and cause the light pattern area in the D1 direction to shrink, and the light in the D2 direction will undergo constructive interference to cause the light pattern area in the D2 direction to increase. The area of the halo pattern in the D1 direction will be destroyed, and its pattern in the D2 direction will be increased, and finally a linear pattern as shown in FIG. 3B is formed, presenting a strip-shaped light pattern effect. Corresponding to the light area 1 and the dark area 2 in the halo pattern, in the linear pattern as shown in Figure 3B, the center is the light area 1, and the two ends are the dark area 2. That is, the dark areas 2 of the light pattern are mainly distributed at the two ends of the long light pattern, and the bright areas 1 are distributed at the central area of the long light pattern. It should be noted that the light pattern formed by the light-emitting element used in the present invention is not limited to the above-mentioned shape. The ratio and position of the dark area and the bright area can be adjusted according to specific design requirements by adjusting the geometric shape and the interference element The direction is achieved. For example, a suitable interference element can also be used to obtain a light pattern with no difference between dark and bright areas.

In detail, the interference element 420 may include a plurality of micro-units, and these micro-units may be arranged regularly or irregularly. The geometric shape of the micro unit can be a triangle, a square, a rectangle, a hexagon, a cone, an ellipsoid, a three-dimensional wave shape, or the base of other polygons, which is not limited here. The micro-units can be protrusions extending from the surface or recesses extending into the surface, and the spacing density between each other can be adjusted as required. These micro-units can be arranged on a concave-convex surface, and the distance between the lowest point and the highest point of the concave-convex surface can be, for example, not more than 500 microns, preferably 100 microns, more preferably 30 microns. When the depth of the uneven surface is smaller, the more micro-units can be arranged, which can increase the interference effect.

In addition, when manufacturing the interference element 420, the length and width of the narrow light pattern H that is finally formed can be adjusted by adjusting the manufacturing angle of the micro unit. For example, during manufacturing, twist 1 degree in the first direction D1 and 60 degrees in the second direction D2 (not shown), so that the first direction D1 has a better destructive interference effect. The greater the twist angle, the destructive interference effect The worse. In other words, it is actually possible to accurately control the shape of the linear pattern by calculating the above-mentioned manufacturing angle, for example, in the same interference element 420 divides different areas, and each area has micro-units with different geometric shapes and manufacturing angles to form light patterns of different shapes. For the convenience of description, the interference element 420 of the following embodiment has only a single manufacturing angle and a single geometric shape, and one of the extension directions D3 of the reflective element 300 and the destructive interference direction of the interference element 420 (ie the aforementioned first direction D1) It is not parallel, so that when the light L is emitted through the light-transmitting element 410, it is a narrow light type H that is arranged in parallel.

Generally speaking, one light source 200 can only form one light pattern on the optical element 400. Therefore, if multiple light patterns are to be formed on the optical element 400, multiple light sources 200 must be provided to achieve the purpose. As shown in FIG. 4, the present invention uses at least one reflective element 300 to allow one light source 200 to form multiple narrow light patterns H on the optical element 400.

Taking two reflective elements as an example, if the left and right reflective elements are placed parallel to the light source (horizontally opposite sides), the light pattern will be three separate straight lines, and vertically (vertically opposite sides) the light patterns will be superimposed into a straight line. When placed diagonally on the same side, the light pattern is denser and closer to the reflective element, while the light pattern is dense and stepped when placed on the diagonally opposite side. When the angle of the reflective surface of the reflective element changes from small to large, the number of light types (also called light type lines) changes from 1 to 3 (the number that can be clearly recognized by the naked eye), and the width between the light type lines becomes larger. When the distance between the reflective element and the light source changes from small to large, the width between the left and right light lines becomes larger and the length becomes smaller (but when the reflector is too far from the light source, there will be no left and right light lines).

Please refer to FIGS. 7A to 7D to reveal the influence of the setting angle of the reflective surface 310 on the light type (C1 is a simple schematic diagram of the light type, and C2 is a schematic diagram of the light type in actual operation). The narrow light type H1 (hereinafter referred to as the light type) generated by the light L directly emitted from the light source 200 to the optical element 400 will not change due to the arrangement of the reflective element 300. The back side of the reflective surface 310 of the reflective element 300 can have an angle A2 with respect to the circuit substrate 100. When the angle A2 is 75 degrees, the light patterns H2 and H3 generated by the reflected light RL reflected by the reflective surface 310 to the optical element 400 are relatively high. It is close to the light type H1 (that is, the complex light type is denser), and is slightly shorter than the light type H1 (as shown in Figure 7A). By analogy, when the angle A2 is smaller, the light patterns H2 and H3 are farther away from the light pattern H1 (that is, the plural light patterns are sparser), and the length is shorter. Glow with light source 200 Take an angle of 120 degrees as an example (for ease of illustration, the figure shows the light-emitting angle more exaggeratedly), the angle A2 can be no less than 30 degrees (that is, half of the supplementary angle of the light-emitting angle of the light source) so that the reflecting surface 310 can smoothly receive the light L. Not more than 80 degrees to produce a more ideal complex light type (it is a complex light type visible to the naked eye). Please refer to Figure 8. Although in the above embodiment, the optical element 400 is substantially parallel to the circuit substrate 100, the angle A2 is preferably not set to be greater than 80 degrees, but when the optical element 400 is set relative to the light source 200 The position changes, for example, the reflective surface 310 and the optical element 400 are located on the opposite side of the light source 200, that is, the optical element 400 and the circuit substrate 100 are not parallel, the angle A2 may be greater than 80 degrees or even greater than 90 degrees to reflect the reflected light RL to the optical element 400 up. The optical element 400 can preferably abut against an upper end of the reflective surface 310 to generate a better light pattern (not shown).

Please refer to FIGS. 9A to 9C to reveal the influence of the setting distance of the reflective surface 310 on the light type. The reflecting surface 310 of the reflecting element 300 and the light source 200 may have the shortest linear distance S. Taking the angle A2 as an example of 45 degrees, when the distance S is 0 mm, the light type H2 and H3 generated by the reflected light RL reflected by the reflective surface 310 to the optical element 400 are closer to the light type H1 (that is, the complex light type is denser) , And slightly shorter than the length of the light type H1 (as shown in Figure 9A). By analogy, when the distance S is larger, the light patterns H2 and H3 are farther away from the light pattern H1 (that is, the plural light patterns are sparser), and the length is shorter. Taking the light-emitting angle of the light source 200 as an example (for ease of illustration, the light-emitting angle is exaggerated in the figure), the distance S is preferably not greater than 6 mm so that the reflective surface 310 can receive the light L smoothly.

Please refer to FIGS. 10A to 10D to show the top view of the two reflective elements 300 when they are adjacent to the light source 200 to reveal the influence of different placement positions on the light type. Take the case where the light emitting angle of the light source 200, the angle A2 and the distance S of the reflecting surface 310 are all fixed as an example. When the two reflecting elements 300 are arranged on the left and right sides of the light source 200, the light patterns H2 and H3 are symmetrically located on both sides of the light pattern H1 (Figure 10A). When the two reflective elements 300 are arranged on the upper left side and the upper right side of the light source 200, the light patterns H2 and H3 move toward the upper end of the light pattern H1 (Figure 10B). When the two reflective elements 300 are arranged on the upper left side and the lower right side of the light source 200, the light pattern H2 moves toward the upper end of the light pattern H1, and the light pattern H3 moves toward the lower end of the light pattern H1 (Figure 10C). If the second reflective element 300 is set When placed on the upper and lower sides of the light source 200 (at this time, the extension direction D3 of the reflective element 300 is parallel to the destructive interference direction D1 of the interference element 420), the complex light type will not be generated (Figure 10D). It should be understood that if the destructive interference direction D1 of the interference element 420 is changed, to generate a complex light pattern, the setting position of the reflective element 300 needs to be changed accordingly. In addition, when the extension direction D3 of the two reflective elements 300 is not parallel to the destructive interference direction D1 of the interference element 420, as shown in Figures 10B and 10C, the reflective surface 310 of the reflective element 300 is between the light source 200 The distance S has a lateral component F. When the distance S is fixed, the lengths of the light patterns H1, H2, and H3 remain unchanged, but the distance between the light patterns H2, H3 and the light pattern H1 will be proportional to the lateral component F.

Please refer to FIG. 11A to FIG. 11B. The top view of the four reflective elements 300 when they are arranged adjacent to the light source 200 reveals the influence of different positions on the light type. Take the case where the light emitting angle of the light source 200, the angle A2 and the distance S of the reflecting surface 310 are all fixed as an example. When the four reflecting elements 300 are equally spaced on the upper left, upper right, lower left and lower right sides of the light source 200, the light patterns H2 and H3 are symmetrically located on both sides of the light pattern H1, and the light patterns H2 and H3 can have Almost the same length as the light type H1 or slightly shorter than the light type H1. When the four reflective elements 300 are equally spaced on the upper, lower, left and right sides of the light source 200, the light patterns H2 and H3 are also symmetrically located on both sides of the light pattern H1, and the light pattern H1 is due to the difference between the upper and lower sides. The reflection element 300 has a longer length, and the light types H2 and H3 are only reflected by the reflection elements 300 on the left and right sides, and the length is shorter.

Through the above embodiments, the light-emitting device provided by the present invention can be applied to various lighting modules (for example, as brake lights, direction lights, headlights, tail lights, or atmosphere lights, etc.) to provide a variety of light types The pattern can achieve the effect of generating multiple light patterns with a smaller number of LEDs, reducing manufacturing costs and facilitating subsequent maintenance.

The above-mentioned embodiments are only used to illustrate the implementation of the present invention and explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any change or equal arrangement that can be easily accomplished by a person familiar with this technology belongs to the scope of the present invention, and the scope of protection of the present invention shall be subject to the scope of the patent application.

10‧‧‧Light-emitting device

100‧‧‧Circuit board

200‧‧‧Light source

300‧‧‧Reflective element

400‧‧‧Optical components

410‧‧‧Transparent element

420‧‧‧Interference element

D1‧‧‧First direction

D2‧‧‧Second direction

D3‧‧‧Extending direction

L‧‧‧Light

RL‧‧‧reflected light

H‧‧‧Narrow light type

Claims (11)

A light emitting device includes: A circuit board; A light source arranged on the circuit substrate; At least one reflective element is adjacent to the light source, and each of the at least one reflective element includes a reflective surface; An optical element, the optical element includes a light-transmitting element and an interference element, and the interference element is disposed under the light-transmitting element; Wherein, the at least one reflecting element and the optical element are located on a path of a light emitted by the light source, so that the light can be reflected by the at least one reflecting element and then emitted from the light-transmitting element through the interference element; Wherein, the interference element has a destructive interference direction, and an extension direction of the reflecting surface is not parallel to the destructive interference direction, so that the light emitted from the light-transmitting element generates a plurality of parallel narrow light patterns. The light-emitting device according to claim 1, wherein the at least one reflective element includes two reflective elements, which are symmetrically arranged adjacent to two opposite sides of the light source. The light emitting device according to claim 1, wherein the at least one reflective element includes four reflective elements, which are arranged adjacent to the light source at equal intervals. The light emitting device of claim 1, wherein the reflective surface is flat in a direction away from the light source. The light emitting device of claim 1, wherein the reflective surface is curved in a direction away from the light source. The light-emitting device of claim 1, wherein the rear side of the reflective surface has an angle with respect to the circuit substrate, and the angle is not less than half of the supplementary angle of the light-emitting angle of the light source. The light emitting device of claim 1, wherein the reflective surface and the optical element are located on opposite sides of the light source. The light emitting device of claim 1, wherein there is a shortest linear distance between the reflective surface and the light source, and the shortest linear distance is not greater than 10 mm. The light emitting device of claim 1, wherein there is a shortest linear distance between the reflective surface and the light source, and the shortest linear distance is not greater than 6 mm. The light-emitting device of claim 1, wherein the at least one reflective element is at least one piece or at least one plate. The light-emitting device of claim 1, wherein the at least one reflective element is disposed on the circuit substrate.

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