TW201904091A - Light emitting device - Google Patents

Abstract

A light emitting device includes a substrate, light emitting units, an insulation layer, a current distribution layer and a reflective layer. The substrate has an upper surface. The light emitting units are disposed on the upper surface and include at least one first light emitting diode (LED) and at least one second LED. A first side wall of the first LED is adjacent to a second side wall of the second LED so as to define a concave portion exposing a portion of the upper surface. The insulation layer at least covers the first side wall and the second side wall. The current distribution layer covers the concave portion and at least covers a portion of the second LED. The reflective layer covers the current distribution layer and is electrically connected to the first LED and the second LED.

Description

Illuminating device

The present invention relates to a light-emitting device, and more particularly to a light-emitting device using a light-emitting diode as a light source.

With the development of the technology of the Light Emitting Diode (LED), the light-emitting diode has been gradually replaced by the conventional light bulb and used in the field of illumination. Since the conventional light-emitting diodes are driven by direct current, they can only be used in a DC-driven environment; or, an AC-DC power converter and a transformer are required to convert a commercial alternating current into a low-voltage direct current to provide a light-emitting diode. Body use.

However, general commercial power consumption is 110V/220V AC power. Therefore, it is conventionally known that a DC light-emitting diode has a problem of inconvenient use. In view of the above, some researchers have developed AC light-emitting diodes (AC LEDs) or high-voltage light-emitting diodes (HV LEDs). The AC light-emitting diodes do not require an additional transformer, rectifier or drive circuit. The AC light-emitting diode is driven, and the high-voltage light-emitting diode does not need to be converted into a low-voltage direct current, and can be driven by a general direct current, thereby reducing the energy loss generated by the transformer.

The current AC/high-voltage light-emitting diodes are formed on a single-chip of a relatively small size to form a matrix of light-emitting diode cells and interconnect lines, and a plurality of light-emitting diode units are connected in series or in parallel by interconnecting lines, so that The AC/High Voltage LEDs are characterized by adjustable voltage and current. In general, interconnect lines are typically made of a transparent conductive material such as indium tin oxide (ITO). Since the interconnecting line can only provide the electrical connection effect, the luminous efficiency at the bridge of the adjacent two light emitting diode units is low.

The invention provides a light-emitting device which can enhance the light reflection effect of the bridge between two adjacent light-emitting diodes to improve the luminous efficiency of the overall light-emitting device.

The invention provides a light emitting device comprising a substrate, a plurality of light emitting units, an insulating layer and a reflective conductive stack. The light emitting unit is disposed on the substrate. The light emitting unit includes at least one first light emitting diode and at least one second light emitting diode. The second light emitting diode and the first light emitting diode are separated from each other. A portion of the substrate is exposed between the first light emitting diode and the second light emitting diode. The insulating layer is disposed on the substrate and covers at least a first sidewall of the first LED and a second sidewall of the second LED. The reflective conductive stack is disposed on the insulating layer and electrically connected to the first light emitting diode and the second light emitting diode.

In an embodiment of the invention, the reflective conductive stack includes a current distribution layer and a reflective layer. The current distribution layer covers at least a portion of the second light emitting diode. The reflective layer covers the current distribution layer and is electrically connected to the first light emitting diode and the second light emitting diode.

In an embodiment of the invention, the reflective conductive stack further includes a barrier layer disposed on the reflective layer.

In an embodiment of the invention, the current distribution layer extends over a portion of the first light emitting diode.

In an embodiment of the invention, the current distribution layer extends over the substrate exposed between the first light emitting diode and the second light emitting diode.

In an embodiment of the invention, the insulating layer covers the plate exposed between the first light emitting diode and the second light emitting diode.

The present invention provides another light emitting device comprising a substrate, a plurality of light emitting units, an insulating layer and a reflective conductive stack. The light emitting unit is disposed on the substrate. The light emitting unit includes at least one first light emitting diode and at least one second light emitting diode. The second light emitting diode and the first light emitting diode are separated from each other. A portion of the substrate is exposed between the first light emitting diode and the second light emitting diode. The insulating layer is disposed on the substrate and covers at least a first sidewall of the first LED and a second sidewall of the second LED. The reflective conductive stack is disposed on the insulating layer and electrically connected to the first light emitting diode and the second light emitting diode. The reflective conductive stack includes a current distribution layer and a plurality of conductive layers. The current distribution layer covers at least a portion of the second light emitting diode. These conductive layers cover the current distribution layer.

In an embodiment of the invention, the conductive layer includes a reflective layer and a barrier layer. The reflective layer covers the current distribution layer and is electrically connected to the first light emitting diode and the second light emitting diode. The barrier layer is disposed on the reflective layer.

Based on the above, the reflective layer of the present invention has electrical conductivity to electrically connect adjacent two light-emitting diodes, and has high reflection efficiency to reflect light emitted from the light-emitting layer of the light-emitting diode. Therefore, the light-emitting device of the present invention can have better luminous efficiency than the conventional high-voltage light-emitting diode.

The above described features and advantages of the invention will be apparent from the following description.

1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention. Referring to FIG. 1, in the embodiment, the light emitting device 100a includes a substrate 110a, a plurality of light emitting units 120, an insulating layer 130a, a current distribution layer 140a, and a reflective layer 150a. The substrate 110a has an upper surface 112a. The light emitting unit 120 is disposed on the upper surface 112a of the substrate 110a. The light emitting unit 120 includes at least one first light emitting diode 120a (only one is schematically shown in FIG. 1) and at least one second light emitting diode 120b (only one is schematically shown in FIG. 1). A first sidewall 127a of the first LED 120a and a second sidewall 127b of the second LED 120b are adjacent to each other and define a recess C, and the recess C exposes a portion of the upper surface 112a of the substrate 110a. The insulating layer 130a covers at least the first sidewall 127a of the first LED body 120a and the second sidewall 127b of the second LED body 120b. The current distribution layer 140a covers the recess C and covers at least a portion of the second light emitting diode 120b. The reflective layer 150a covers the current distribution layer 140a and is electrically connected to the first light emitting diode 120a and the second light emitting diode 120b.

More specifically, the first LED 220a of the present embodiment includes a first semiconductor device layer 122a, a first electrode 124a, and a second electrode 126a. The first semiconductor element layer 122a of the first light emitting diode 120a is composed of a first semiconductor layer 121a, a first light emitting layer 125a and a second semiconductor layer 123a. The first light emitting layer 125a is disposed between the first semiconductor layer 121a and the second semiconductor layer 123a. The first electrode 124a is located on the first semiconductor layer 121a and the insulating layer 130a covers a portion of the first semiconductor layer 121a. The second light emitting diode 120b includes a second semiconductor element layer 122b and a third electrode 124b. The second semiconductor device layer 122b of the second LED 220b is composed of a third semiconductor layer 121b, a second luminescent layer 125b, and a fourth semiconductor layer 123b. The second light emitting layer 125b is disposed between the third semiconductor layer 121b and the fourth semiconductor layer 123b. The third electrode 124b is located on the third semiconductor layer 121b. The insulating layer 130a further covers a portion of the fourth semiconductor layer 123b and a portion of the upper surface 112a of the substrate 110a exposed by the recess C. That is, the insulating layer 130a is a continuous film layer covering the first side wall 127a, the second side wall 127b, and a portion of the upper surface 112a of the substrate 110a exposed by the recess C. The current distribution layer 140a covers a portion of the first electrode 124a and the second semiconductor layer 123a and the second semiconductor element layer 122b of the second light emitting diode 120b. In particular, the current distribution layer 140a covers a portion of the fourth semiconductor layer 123b, and the current distribution layer 140a forms an ohmic contact with the fourth semiconductor layer 123b. The reflective layer 150a further covers the current distribution layer 140a on the second semiconductor layer 123a, and the second electrode 126a is on the reflective layer 150a. In particular, the reflective layer 150a is electrically connected to the first electrode 124a of the first LED body 120a and the second semiconductor device layer 122b of the second LED body 120b. Here, the first light-emitting diode 120a and the second light-emitting diode 120b are respectively a flip-chip light-emitting diode. In this embodiment, the first sidewall 127a of the first LED 120a and the second sidewall 127b of the second LED 120b are respectively a vertical sidewall. That is, the first side wall 127a and the second side wall 127b are disposed in parallel with each other. Of course, in the other embodiments, the first sidewall 127a of the first LED 120a and the second sidewall 127b of the second LED 120b may also be a sloping sidewall, respectively. limit. Furthermore, the insulating layer 130a of the present embodiment is, for example, a single-layer material structure layer, wherein the material of the insulating layer 130 is, for example, tantalum oxide or titanium nitride. Of course, in other embodiments not shown, the insulating layer 130a may also be composed of two or more different refractive index materials, which are not limited herein. In addition, the material of the current distribution layer 140a of the present embodiment is, for example, nickel/gold, indium tin oxide, cadmium tin oxide, antimony tin oxide, zinc oxide, or a combination thereof, wherein the current distribution layer 140a has a good current dispersion function. Here, the current distribution layer 140a also has a second semiconductor element layer 122b electrically connected to the first electrode 124a of the first light emitting diode 120a and the second light emitting diode 120b.

In particular, in the present embodiment, in addition to having high reflection efficiency, the reflective layer 150a has electrical efficacy to electrically connect the first LED body 120a and the second LED body 120b. That is, the first light emitting diode 120a and the second light emitting diode 120b of the present embodiment are electrically connected to each other in series or in parallel through the reflective layer 150a. Here, the reflective layer 150a may be a single metal layer, wherein the material of the reflective layer 150a is, for example, silver, titanium, aluminum, gold, chromium, nickel, platinum or an alloy thereof. Of course, in other embodiments not shown, the reflective layer 150a may also be composed of a plurality of layers of metals or metal alloys having different reflectivity materials, which are not limited herein.

In addition, in order to prevent metal diffusion, to further improve the luminous efficiency of the overall light-emitting device 100a, the light-emitting device 100a of the present embodiment may further include a barrier layer 160, wherein the barrier layer 160 is disposed on the reflective layer 150a. In other words, the barrier layer 160 also bridges the first semiconductor layer 124a of the first LED body 120a and the fourth semiconductor layer 123b of the second LED body 120b, and is disposed on the first LED body 120a. The two electrodes 126a are interposed between the second semiconductor layer 123a of the first semiconductor element layer 122a. Here, the material of the barrier layer 160 is, for example, tungsten, titanium tungsten or titanium tungsten/platinum. The material used for the barrier layer 160 described above is not only a diffusion barrier but also a good reflective metal.

The reflective layer 150a of the present embodiment has high electrical efficiency, and is electrically connected to the adjacent first and second light emitting diodes 120a and 120b. Light emitted by the first light-emitting layer 125a and the second light-emitting layer 125b of the light-emitting diode 120a and the second light-emitting diode 120b. Therefore, in this embodiment, the bridge between the adjacent two first LEDs 120a and the second LEDs 120b is compared with the conventional high-voltage LEDs that use a transparent conductive material as the interconnecting line. It can have better reflection efficiency. In this way, the light-emitting device 100a of the embodiment can have better luminous efficiency. In addition, the barrier layer 160 disposed on the reflective layer 150a of the present embodiment has a good reflection effect in addition to being a diffusion barrier. Therefore, the arrangement of the barrier layer 160 also contributes to improving the luminous efficiency of the overall light-emitting device 100a.

It is to be noted that the following embodiments use the same reference numerals and parts of the above-mentioned embodiments, and the same reference numerals are used to refer to the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted portions, reference may be made to the foregoing embodiments, and the following embodiments are not repeated.

2 is a schematic view showing a cross section of a light-emitting device according to another embodiment of the present invention. Referring to FIG. 2, the illuminating device 100b of the present embodiment is similar to the illuminating device 100a of FIG. 1, except that the current distribution layer 140b of the illuminating device 100b of the present embodiment covers the substrate 110a exposed by the recess C. The upper surface 112a is partially covered, but does not cover the first electrode 124a of the first LED 120a. That is, the current distribution layer 140b contacts the reflective layer 150b, the fourth semiconductor layer 123b of the second light emitting diode 120b, the insulating layer 130b, and a portion of the upper surface 112a of the substrate 110a exposed by the recess C. Here, the insulating layer 130b is a discontinuous film layer covering only the first sidewall 127a and the second sidewall 127b.

3 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention. Referring to FIG. 3, the illuminating device 100c of the present embodiment is similar to the illuminating device 100b of FIG. 2, except that the insulating layer 130c of the illuminating device 100c of the present embodiment further covers the substrate 110a exposed by the recess C. Part of the upper surface 112a. That is, the insulating layer 130c is a continuous film layer covering the first side wall 127a, the second side wall 127b, and a portion of the upper surface 112a of the substrate 110a exposed by the recess C. The current distribution layer 140c contacts only the reflective layer 150b, the fourth semiconductor layer 123b of the second light emitting diode 120b, and the insulating layer 130c.

4 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention. Referring to FIG. 4, the illuminating device 100d of the present embodiment is similar to the illuminating device 100b of FIG. 2, except that the upper surface 112b of the substrate 110b of the illuminating device 100d of the present embodiment has a recess 113b, wherein the recess 113b corresponds to The recess C is disposed, and the insulating layer 130d extends into the recess 113b and covers the recess 113b. That is, the insulating layer 130d is a continuous film layer covering the first side wall 127a and the second side wall 127b and extending into the recess 113b and covering the recess 113b. The current distribution layer 140d contacts only the reflective layer 150b, the fourth semiconductor layer 123b of the second light emitting diode 120b, and the insulating layer 130d.

FIG. 5 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention. Referring to FIG. 5, the light-emitting device 100e of the present embodiment is similar to the light-emitting device 100d of FIG. 4, except that the insulating layer 130e of the light-emitting device 100e of the present embodiment extends into the recess 113b and does not cover the recess 113b. A bottom 115b. That is, the insulating layer 130e is a discontinuous film layer covering only the first side wall 127a and the second side wall 127b and extending into the recess 113b. The current distribution layer 140e contacts the reflective layer 150b, the fourth semiconductor layer 123b of the second light emitting diode 120b, the insulating layer 130e, and the bottom 115b of the recess 113b.

It is worth mentioning that the present invention does not limit the electrical conduction state of the current distribution layers 140b, 140c, 140d, 140e in the light-emitting devices 100b, 100c, 100d, 100e, although the current distribution layers 140b, 140c mentioned herein 140d, 140e is embodied as a function of not having electrical conduction, that is, the first electrode 124a of the first light-emitting diode 120a and the second semiconductor element layer 122b of the second light-emitting diode 120b are not transmitted through the current distribution layer 140b. , 140c, 140d, 140e are electrically connected, but through the reflective layer 150b to achieve electrical conduction. However, in other embodiments not shown, the current distribution layer 140a having an electrical conduction function as mentioned in the foregoing embodiments may be selected, and those skilled in the art may refer to the description of the foregoing embodiments, according to the description. For the actual needs, the aforementioned components are selected to achieve the desired technical effect.

In summary, the reflective layer of the present invention has electrical conductivity to electrically connect adjacent two light-emitting diodes, and has high reflection efficiency to reflect light emitted from the light-emitting layer of the light-emitting diode. Therefore, the light-emitting device of the present invention can have better luminous efficiency than the conventional high-voltage light-emitting diode.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100a, 100b, 100c, 100d, 100e‧‧‧ illuminating devices

110a, 110b‧‧‧ substrate

112a, 112b‧‧‧ upper surface

113b‧‧‧ dent

115b‧‧‧ bottom

120‧‧‧Lighting unit

120a‧‧‧first light-emitting diode

120b‧‧‧Second light-emitting diode

121a‧‧‧First semiconductor layer

121b‧‧‧ third semiconductor layer

122a‧‧‧First semiconductor component layer

122b‧‧‧Second semiconductor component layer

123a‧‧‧Second semiconductor layer

123b‧‧‧fourth semiconductor layer

124a‧‧‧first electrode

124b‧‧‧ third electrode

125a‧‧‧first luminescent layer

125b‧‧‧second luminescent layer

126a‧‧‧second electrode

127a‧‧‧First side wall

127b‧‧‧ second side wall

130a, 130b, 130c, 130d, 130e‧‧‧ insulation

140a, 140b, 140c, 140d, 140e‧‧‧ current distribution layer

150a, 150b‧‧‧reflective layer

160‧‧‧Barrier layer

C‧‧‧ recess

1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention. 2 is a schematic view showing a cross section of a light-emitting device according to another embodiment of the present invention. 3 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention. 4 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a light emitting device according to still another embodiment of the present invention.

Claims (2)

A light-emitting device, comprising: a substrate; a plurality of light-emitting units disposed on the substrate, the light-emitting units comprising: at least one first light-emitting diode; and at least one second light-emitting diode, and the first light-emitting device The diodes are separated from each other and form a gap, the gap exposing a portion of the substrate; an insulating layer covering at least a portion of the gap, a portion of the first light emitting diode, a first sidewall, and the second light emitting diode And a reflective layer disposed on the substrate, and at least Covering a portion of the current distribution layer, a portion of the first light emitting diode, and a portion of the second light emitting diode. The illuminating device of claim 1, further comprising a metal layer disposed on the reflective layer and covering at least a portion of the reflective layer, a portion of the first illuminating diode, and a portion of the second illuminating dipole body.