Light emitting device

Abstract

The invention discloses a light emitting device. The light-emitting device includes a substrate, a reflective layer disposed on the substrate, a plurality of light-emitting elements disposed on the substrate and in the reflective layer, and a plurality of light-transmitting elements disposed on the plurality of light-emitting elements and in the reflective layer. A plurality of upper surfaces of the plurality of light-transmitting elements are exposed from the reflective layer. A first micron-order spacing is arranged between two adjacent light-transmitting elements in the plurality of light-transmitting elements. The reflective layer includes a light-reflective material and a light-absorbing material.

Description

Technical Field

[0001] The present invention relates to a light-emitting device. Background Art

[0002] A light-emitting diode (LED) is a semiconductor light-emitting element, which has been widely used in various fields, such as lighting devices, display devices, etc.

[0003] A headlight LED device, especially an adaptive driving beam headlamp (ADB), is a light-emitting device composed of multiple LED chips, and a reflective colloid is filled between the LED chips. However, under the trend of miniaturization, the distance between the LED chips is continuously reduced, and the thickness of the reflective layer formed by the commercially available reflective colloid is insufficient to completely reflect the light emitted by the LED chips, resulting in light penetrating the reflective layer and reducing the brightness and contrast of the device. Summary of the Invention

[0004] In view of the above problems, the present invention provides an improved light-emitting device. The light-emitting device includes an improved reflective layer to enable the light-emitting device to have good contrast and luminous flux, and can improve the efficiency of the light-emitting device.

[0005] According to an embodiment of the present invention, there is provided a light-emitting device, including a substrate, a reflective layer, a plurality of light-emitting elements, and a plurality of light-transmitting elements. The reflective layer is disposed on the substrate. The plurality of light-emitting elements are disposed on the substrate and within the reflective layer. The plurality of light-transmitting elements are disposed on the plurality of light-emitting elements and within the reflective layer, wherein the upper surfaces of the plurality of light-transmitting elements are exposed from the reflective layer, and there is a first micrometer-level spacing between two adjacent light-transmitting elements among the plurality of light-transmitting elements. The reflective layer includes a light-reflective material and a light-absorbing material.

[0006] In order to have a better understanding of the above and other aspects of the present invention, specific embodiments are given below and described in detail in conjunction with the accompanying drawings as follows. Brief Description of the Drawings

[0007] Figure 1 A schematic diagram of a light-emitting device according to an embodiment of the present invention;

[0008] Figure 2 A schematic cross-sectional view of a light-emitting device according to an embodiment of the present invention;

[0009] Figure 3 A contrast curve of a light-emitting device according to an embodiment of the present invention;

[0010] Figure 4 A schematic cross-sectional view of a light-emitting device according to another embodiment of the present invention;

[0011] Figure 5 A schematic top view of a light-emitting device according to an embodiment of the present invention; and

[0012] Figure 6 A measuring method for a light-emitting device according to an embodiment of the present invention.

[0013] Wherein, reference numerals:

[0014] 10: Light-emitting device;

[0015] 101: Substrate;

[0016] 101B: Lower surface;

[0017] 101U, 103U, 105U, 106U: Upper surface;

[0018] 102: Carrier substrate;

[0019] 103: Reflective layer;

[0020] 104: Conductive element;

[0021] 105, 105-1, 105-2, 305: Light-emitting element;

[0022] 106: Light-transmitting element;

[0023] AA’: Section line;

[0024] G1, G2, G3: Micron-level spacing;

[0025] T1, T2: Thickness;

[0026] TA, TB: Detection area. Detailed implementation manners

[0027] The following are the proposed related embodiments, which are described in detail in conjunction with the accompanying drawings for the light-emitting device proposed by the present invention. The accompanying drawings are simplified to clearly illustrate the content of the embodiments, and the dimensional ratios on the drawings are not drawn in proportion to the actual products. Therefore, the description and the drawings are only used to describe the embodiments, rather than to limit the protection scope of the present invention. The same or similar component symbols are used to represent the same or similar components. Furthermore, the ordinal numbers such as "first", "second", etc. used in the description and the claims are used to modify the elements, and they do not themselves imply and represent that the elements have any previous ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only to clearly distinguish an element with a certain name from another element with the same name.

[0028] As used herein, the term "micrometer scale" refers to dimensions on the micrometer level, for example, it can range from 1 μm to 100 μm.

[0029] Please also refer to Figure 1 and Figure 2 . Figure 1 FIG. is a schematic diagram of a light-emitting device 10 according to an embodiment of the present invention. Figure 2 is a schematic cross-sectional view of the light-emitting device 10 taken along the AA' cross-sectional line shown in Figure 1 . The light-emitting device 10 includes a substrate 101, a reflective layer 103, a plurality of light-emitting elements 105, and a plurality of light-transmitting elements 106. The substrate 101 has an upper surface 101U and a lower surface 101B. The upper surface 101U may include a circuit layer (not shown). The reflective layer 103 is disposed on the upper surface 101U of the substrate 101. In addition, as shown in Figure 1 , the light-emitting device of the present invention can be carried on a carrier substrate 102. In other words, the reflective layer 103 is disposed on the upper surface 101U of the substrate 101. The lower surface 101B of the substrate 101 is opposite to the upper surface 101U of the substrate 101. The lower surface 101B of the substrate 101 can face the carrier substrate 102, that is, the reflective layer 103 and the carrier substrate 102 are respectively located on opposite sides of the substrate 101. In an embodiment, the reflective layer 103 can cover the entire upper surface 101U of the substrate 101. In addition, the lower surface 101B may also include a circuit layer (not shown), and the carrier substrate 102 may include a driving circuit, which is electrically connected to the circuit layer of the lower surface 101B to drive the plurality of light-emitting elements 105. The carrier substrate 102 can be, for example, various types of circuit boards. In the present invention, the substrate 101 and the carrier substrate 102 can be any substrates commonly used in the industry, such as a printed circuit board (PCB), a metal substrate, or a ceramic substrate, etc. In an embodiment, the substrate 101 is exemplified as a ceramic substrate to provide better heat dissipation, and the carrier substrate 102 is exemplified as a metal core printed circuit board (MCPCB) to facilitate customers to lock.

[0030] The light-emitting element 105 is disposed in the reflective layer 103 and electrically connected to the circuit layer on the substrate 101. The reflective layer 103 surrounds the side surfaces of each light-emitting element 105 to achieve a reflection effect. In other words, a part of the light emitted by the light-emitting element 105 can leave the light-emitting element 105 from the side surface of the light-emitting element 105 and enter the reflective layer 103, and the reflective layer 103 can reflect the incident light to the light-transmitting element 106 to improve the light-emitting efficiency. A part of the light emitted by the light-emitting element 105 can leave the light-emitting element 105 from the upper surface 105U of the light-emitting element 105 and enter the light-transmitting element 106 without passing through the reflective layer 103. In the present invention, the light-emitting element 105 can be any form of light-emitting chip, such as a horizontal, vertical, or flip-chip light-emitting chip. Those skilled in the art related to the present invention can select the fixing and electrical connection means according to the chip form. For example, in Figure 2 the illustrated embodiment, the light-emitting element 105 is a flip-chip light-emitting chip, which is fixed on the substrate 101 through a plurality of conductive elements 104 and electrically connected to the circuit layer thereon. The conductive element 104 can be a commonly used conductive die-bonding material in the industry, such as solder or conductive die-bonding glue. In addition, the wavelengths of the light emitted by the plurality of light-emitting elements 105 can be the same or different from each other.

[0031] A plurality of light-transmitting elements 106 are disposed on the plurality of light-emitting elements 105 and in the reflective layer 103. The light-transmitting element 106 can be adhesively fixed on the light-emitting element 105 through a transparent adhesive material. The light-emitting element 105 is protected by the light-transmitting element 106 and the reflective layer 103. Viewed from the cross-section of the device, the plurality of light-transmitting elements 106 are separated from each other by the reflective layer 103. The reflective layer 103 can fill the spacing between the plurality of light-transmitting elements 106. The reflective layer 103 can surround the side surface of each light-transmitting element 106 to reflect the light emitted from the side surface of the light-transmitting element 106 to its front light emission, thereby controlling the light-emitting angle and improving the contrast and brightness. The matrix of the light-transmitting element 106 can be a polymer material, a ceramic material, or a glass material, preferably a ceramic material, to provide better light conversion efficiency, protection effect, weather resistance, and heat resistance. The upper surface 103U of the reflective layer 103 can be coplanar with or slightly higher than the upper surface 106U of the light-transmitting element 106. The light-transmitting element 106 can include a light conversion material. To convert part of the light emitted by the chip, and combine the converted light with the light of the remaining chips to produce different colors. The light conversion material can include a fluorescent material, a phosphorescent material, a quantum dot material, or any combination thereof, such as yttrium aluminum garnet phosphor (YAG), silicate phosphor, nitride phosphor, oxynitride phosphor, etc. In one embodiment, a blue light-emitting diode chip can be used as the light-emitting element 105, and yellow YAG phosphor is added to the light-transmitting element 106 so that the light-emitting device 10 can emit white light.

[0032] In the present invention, the reflective layer 103 contains, in addition to a matrix and a light-reflective material, a light-absorbing material. The reflective layer may be a polymer material. For example, the polymer material may include silicone resin, epoxy resin, etc. In one embodiment, the polymer material is silicone gel. The polymer material may be optically transparent or translucent.

[0033] The light-reflective material is any suitable material that can improve the light-reflection efficiency and / or light extraction rate of the reflective layer 103. The light-reflective material may be selected from at least one of the group consisting of silicon dioxide (SiO2), titanium dioxide (TiO2), boron nitride (BN), aluminum oxide (Al2O3), and zirconium dioxide (ZrO2). In one embodiment, the light-reflective material is titanium dioxide. The light-reflective material may have a particle size of 0.5 μm to 10 μm. Alternatively, the light-reflective material may have a particle size of 1 μm to 7 μm. Alternatively, the light-reflective material may have a particle size of 4 μm to 6 μm. In one embodiment, the light-reflective material has a particle size of 5 μm. With respect to the total weight of the reflective layer 103, the content of the light-reflective material may be 40 wt% to 50 wt%. When the content of the light-reflective material is greater than 50 wt%, the fluidity of the reflective layer precursor is too poor to be filled into the micron-scale spacing. When the content of the light-reflective material is less than 20 wt%, the content of the light-reflective material is insufficient to exert the reflection effect, resulting in low contrast and light flux of the light-emitting device 10.

[0034] As described above, for micron-scale spacing, there are concentration limitations for the light-reflective material. In this case, the present invention particularly adds a light-absorbing material to further improve the contrast. In other words, filling in the light-absorbing material will reduce the light flux. The present invention particularly balances the contrast and brightness to meet the requirements of the headlight. The light-absorbing material may be any suitable material that selectively absorbs or blocks light of a specific wavelength, and may include, for example, carbon-containing materials such as carbon black, graphene, graphite, carbon nanotubes, or any combination thereof. In one embodiment, the light-absorbing material is carbon black. With respect to the total weight of the reflective layer 103, the content of the light-absorbing material may be 0.15 wt% to 1.0 wt%. Alternatively, with respect to the total weight of the reflective layer 103, the content of the light-absorbing material may be 0.2 wt% to 0.75 wt%. If the concentration is lower than 0.15 wt%, the light absorption effect is insufficient to improve the contrast, as Figure 3 shown. From Figure 3 the contrast curve, it can be seen that when the concentration approaches 1.0 wt%, the increase in contrast slows down, that is, the increase in contrast will approach the limit. At this time, if the light-absorbing material is further increased, the improvement in contrast is limited, but the light flux will decrease severely.

[0035] As Figure 2 shown, there is a micron-level spacing G1 in the lateral direction between two adjacent light-transmitting elements 106 among the plurality of light-transmitting elements 106, and there is a micron-level spacing G2 in the lateral direction between two adjacent light-emitting elements 105 among the plurality of light-emitting elements 105. The micron-level spacing G1 can be approximately equal to or equal to the micron-level spacing G2. The lateral direction can be perpendicular to the longitudinal direction. The micron-level spacing G1 can be 10 μm to 100 μm, and the micron-level spacing G2 can be 10 μm to 100 μm. Specifically, the micron-level spacings G1 between the plurality of light-transmitting elements 106 can be the same as or different from each other; the micron-level spacings G2 between the plurality of light-emitting elements 105 can also be the same as or different from each other. In one embodiment, the micron-level spacing G1 can be 25 μm, and the micron-level spacing G2 can be 25 μm. In this embodiment, the size (such as width) of the light-transmitting element 106 in the lateral direction can be approximately equal to or equal to the size (such as width) of the light-emitting element 105 in the lateral direction. The side surface of the light-transmitting element 106 can be coplanar with the side surface of the light-emitting element 105 below this light-transmitting element 106.

[0036] In other embodiments, the micron-level spacing between two adjacent light-transmitting elements 106 among the plurality of light-transmitting elements 106 can be smaller than the micron-level spacing between two adjacent light-emitting elements 105 among the plurality of light-emitting elements 105, as Figure 4 shown. In Figure 4 , there is a micron-level spacing G1 in the lateral direction between two adjacent light-transmitting elements 106 among the plurality of light-transmitting elements 106, and there is a micron-level spacing G3 in the lateral direction between two adjacent light-emitting elements 305 among the plurality of light-emitting elements 305. The micron-level spacing G1 can be smaller than the micron-level spacing G3. The plurality of micron-level spacings G3 can be the same as or different from each other. The micron-level spacing G3 can be 10 μm to 100 μm. In this embodiment, the size (such as width) of the light-transmitting element 106 in the lateral direction can be larger than the size (such as width) of the light-emitting element 305 in the lateral direction.

[0037] Please refer to Figure 1 again with Figure 2。The light-transmitting element 106 may have a thickness T1 in the longitudinal direction, and the light-emitting element 105 may have a thickness T2 in the longitudinal direction. The thickness T1 of the light-transmitting element 106 may be 50 μm to 150 μm. When the thickness T1 is greater than 150 μm, the contrast will decrease significantly. When the thickness T1 is less than 50 μm, the light-transmitting element 106 is prone to breakage. The thickness T2 of the light-emitting element 105 may be 50 μm to 150 μm. When the thickness T2 is greater than 150 μm, the contrast will decrease significantly. When the thickness T2 is less than 50 μm, the light-emitting element 105 is prone to breakage. The thicknesses of the plurality of light-transmitting elements 106 in the longitudinal direction may be the same as or different from each other. The thicknesses of the plurality of light-emitting elements 105 in the longitudinal direction may be the same as or different from each other.

[0038] The light-emitting device 10 of the present invention may include any number of light-emitting elements 105 and any number of light-transmitting elements 106, and may be configured as a light-emitting array in any arrangement. For example, the light-emitting device may include 102 light-emitting elements 105 and 102 light-transmitting elements 106, and may be configured as a light-emitting array as shown in Figure 5 . Figure 5 FIG. is a schematic top view of the light-emitting device, and only shows the light-emitting elements 105, the light-transmitting elements 106, and the reflective layer 103 in the light-emitting device. For other elements in the light-emitting device, please refer to Figure 1 , 2 and 4.

[0039] The present invention will be described below through a plurality of examples and comparative examples. However, the present invention is not limited to the components, contents, particle sizes, etc. disclosed in the following examples.

[0040] According to Figures 1 to 2 the shown structure, a light-emitting device is prepared. The polymer material and the light-reflective material are mixed according to the components and contents in Table 1 below, and the mixed material is filled between a plurality of light-emitting elements and a plurality of light-transmitting elements to form a reflective layer, obtaining the light-emitting devices of Examples 1 to 6 and Comparative Example 1. Among them, the areas of the light-emitting elements and the light-transmitting elements are about 50 μm × 50 μm, the thickness of the light-transmitting element is 120 μm, the thickness of the light-emitting element is 150 μm, and the micron-level spacing G2 is all 25 μm. In Examples 1 to 6 and Comparative Example 1, the polymer material is transparent silica gel, the light-reflective material is titanium dioxide, and the content of the light-reflective material is relative to the total weight of the reflective layer. The light-emitting device of Comparative Example 1 does not include a reflective layer, and there is air (air gap) between the plurality of light-emitting elements and the plurality of light-transmitting elements. The contrast ratios of the light-emitting devices of Examples 1 to 6 and Comparative Example 1 are measured using the following measuring equipment, parameters, and measuring methods, and the measurement results are listed in Table 1 below.

[0041] Measuring Equipment and Parameters

[0042] Measuring device: LumiCam 2400B (manufactured by Instrument Systems, Germany).

[0043] Lens: Canon 24mm with OD4 filter.

[0044] Iris F / number: 16.

[0045] Distance between the sample and the measuring device: 0.3 m.

[0046] Take Figure 6 the light-emitting device (sample) shown as an example. All the light-emitting elements except the light-emitting element 105-2 in the light-emitting device (including a plurality of light-emitting elements 105 and a plurality of light-emitting elements 105-1) are lit with a current of 10 mA, that is, the light-emitting element 105-2 is deliberately not lit. Use the LumiCam 2400B display to measure the brightness value (cd / mm2) of a detection area TB in the unlit light-emitting element 105-2 and the brightness values of the detection areas TA in three light-emitting elements 105-1 adjacent to the unlit light-emitting element 105-2. Calculate the average value of the brightness values of the three detection areas TA, and divide the brightness value of the detection area TB by the average value of the brightness values of the detection areas TA to obtain the contrast. The area of the detection area TA is 300 μm × 300 μm. The area of the detection area TB is 300 μm × 300 μm.

[0047] Table 1

[0048]

[0049] As shown in Table 1, when a light-reflective material is added to the polymer material, the contrast performance of the light-reflective material with a particle size of 5 μm is better than that with a particle size of 0.5 μm. Generally speaking, when the content of the light-reflective material is between 20 wt% and 50 wt%, the contrast of the light-emitting device is improved. However, when the content of the light-reflective material rises to 60 wt%, regardless of whether the particle size is 5 μm or 0.5 μm, the fluidity of the reflective layer precursor is too poor, and some gaps cannot be filled, so the light-emitting elements cannot be completely protected.

[0050] According to Figures 1 to 2Fabricate a light-emitting device with the structure shown. Mix a polymer material, a light-reflective material, and a light-absorbing material according to the components and contents in Table 2 below, and fill the mixed material between multiple light-emitting elements and multiple light-transmitting elements to form a reflective layer, obtaining the light-emitting devices of Examples 5 to 12 and Comparative Examples 4 to 6. In Examples 5 to 12 and Comparative Examples 4 to 6, the area of the light-emitting element and the light-transmitting element is approximately 525 μm × 665 μm, the thickness of the light-transmitting element is 120 μm, the thickness of the light-emitting element is 100 μm, and the micron-scale spacing G2 is all 25 μm. In Examples 5 to 12 and Comparative Examples 4 to 5, the polymer material is transparent silica gel, the light-reflective material is titanium dioxide, the light-absorbing material is carbon black, and the contents of the light-reflective material and the light-absorbing material are relative to the total weight of the reflective layer. The reflective layer of the light-emitting device in Comparative Example 5 does not contain a light-absorbing material. The light-emitting device in Comparative Example 6 does not contain a reflective layer, and there is air (air gap) between the multiple light-emitting elements and the multiple light-transmitting elements. Measure the contrast ratio and luminous flux of the light-emitting devices of Examples 5 to 12 and Comparative Examples 4 to 6 using the aforementioned measurement equipment and parameters, and the measurement results are listed in Table 2 below.

[0051] Table 2

[0052]

[0053] Compared with Examples 1 to 4 shown in Table 1, the thickness of the light-emitting element is reduced in Examples 5 to 12 shown in Table 2, and a light-absorbing material is additionally added to the reflective layer. Comparing Example 2 and Comparative Example 5, it can be seen that when the thickness of the light-emitting element is reduced, the contrast ratio will increase. In addition, when the content of the light-absorbing material is between 0.15 wt% and 1.0 wt%, the light-emitting device has a high contrast ratio, and the luminous flux is maintained within an appropriate range without being too low, achieving a good balance between the contrast ratio and the luminous flux, and improving the luminous efficiency of the light-emitting device. In addition, although the light-emitting device in Comparative Example 4 has a high luminous flux, its contrast ratio is not good. The contrast ratio of the light-emitting device in Comparative Example 5 is lower than that of the light-emitting devices in Examples 5 to 12, indicating that the use of a light-absorbing material in the reflective layer can improve the contrast ratio. The contrast ratio of the light-emitting device in Comparative Example 6 is much lower than that of the light-emitting devices in Examples 5 to 12, indicating that the use of the material combination of the reflective layer of the present invention can significantly improve the contrast ratio.

[0054] As shown in Table 2, the light-emitting devices of the present invention all have a contrast ratio of 25 or more and a luminous flux of 39 lumens or more, and can maintain a good balance between the contrast ratio and the luminous flux while ensuring a high contrast ratio. Therefore, the light-emitting devices of the present invention can have both good contrast ratio and good luminous flux, and can effectively improve the luminous efficiency, heat dissipation, reliability and performance. Moreover, the present invention uses a packaging technology to directly dispose the light-emitting diode chip on the substrate to form a light-emitting device with a micron-level pitch, which can easily change the arrangement and number of the light-emitting elements to adapt to different usage scenarios, and contributes to the miniaturization of the light-emitting device.

[0055] It should be noted that the above-mentioned drawings, structures and steps are used to describe some embodiments or application examples of the present invention, and the present invention is not limited to the scope and application modes of the above-mentioned structures and steps. Embodiments of other different structural modes, for example, known components of different internal components can be applied, and the example structures and steps can be adjusted according to the requirements of actual applications. Therefore, the structures of the drawings are only used for illustration and not for limiting the present invention. Those with ordinary knowledge should know that in the process of applying the relevant structures and steps of the present invention, such as the arrangement or configuration of relevant elements and layers in the light-emitting device and the light-emitting diode, or the details of the manufacturing steps, etc., may be adjusted and changed according to the requirements of the actual application mode.

[0056] In summary, although the present invention has been disclosed above with embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to that defined by the appended claims.

Claims

1. A light emitting device, characterized in that: Include: a substrate; a reflective layer disposed on the substrate; A plurality of light emitting elements are disposed on the substrate and in the reflective layer; and A plurality of light-transmitting elements are disposed on the plurality of light-emitting elements and in the reflective layer, wherein a plurality of upper surfaces of the plurality of light-transmitting elements are exposed from the reflective layer, and a first micrometer-level interval exists between two adjacent light-transmitting elements in the plurality of light-transmitting elements, The reflective layer includes a light reflective material and a light absorbing material.

2. The light emitting device according to claim 1, characterized in that: The content of the light absorbing material is 0.15 wt % to 1.0 wt % relative to the total weight of the reflective layer.

3. The light emitting device according to claim 1, characterized in that: The light-transmitting element includes a light-converting material.

4. The light emitting device according to claim 1, characterized in that: The plurality of light emitting elements are separated from each other by the reflective layer, and the plurality of light-transmitting elements are separated from each other by the reflective layer.

5. The light emitting device according to claim 1, characterized in that: There is a second micrometer-level interval between two adjacent light-emitting elements among the plurality of light-emitting elements, and the first micrometer-level interval is less than or equal to the second micrometer-level interval.

6. The light emitting device according to claim 5, characterized in that: The first micrometer-level spacing is 10 μm to 100 μm.

7. The light emitting device according to claim 1, characterized in that: An upper surface of the reflective layer is coplanar with an upper surface of the plurality of light-transmitting elements.

8. The light emitting device according to claim 1, characterized in that: Also includes: A plurality of conductive elements are disposed on the substrate and between the substrate and the plurality of light emitting elements, wherein each of the plurality of light emitting elements is electrically connected to two conductive elements among the plurality of conductive elements.

9. The light emitting device according to claim 1, characterized in that: The content of the light absorbing material is 0.2 wt % to 0.75 wt % relative to the total weight of the reflective layer.

10. The light emitting device according to claim 1, characterized in that: The light reflective material has a particle size of 0.5 μm to 10 μm.

11. The light emitting device according to claim 1, characterized in that: The content of the light reflective material is 20 wt % to 50 wt % relative to the total weight of the reflective layer.

12. The light emitting device according to claim 1, characterized in that: The reflective layer includes a polymer material.

13. The light emitting device according to claim 12, characterized in that: The light absorbing material is carbon black.

14. The light emitting device according to claim 12, characterized in that: The light reflective material is selected from at least one of the group consisting of SiO2, TiO2, BN, Al2O3, and ZrO2.

15. The light emitting device according to claim 1, characterized in that: The light emitting device has a contrast ratio of more than 25.

16. The light emitting device according to claim 1, characterized in that: The light emitting device has a luminous flux of more than 39 lumens.

Images