TWI464916B - Light emitting device - Google Patents

Description

Illuminating device

The present invention relates to light emitting devices, and more particularly to light emitting devices for light emitting wafers.

About half of the packaged light-emitting diodes (LEDs) are used in mobile phone related fields, and the backlight unit (BLU) in the mobile phone display device is mainly used. In order to make the backlight unit lighter and thinner, in addition to using a side-view package (SVP) technology, the package thickness is continuously reduced. In some configurations of the side-emitting type package, the wafer of the light-emitting diode is sealed at the bottom of a bowl-shaped or cup-shaped structure (bowl structure) made of a material of a transparent resin, and facing the bowl or the cup. The direction of the light. With the package of such a structure, in the process of continuously thinning it, problems may occur, such as a decrease in the thickness of the resin cup, a light leakage, a small cup mouth, a step of performing dispensing, and a cup angle not being the most. The loss of side light, etc., occurs, resulting in loss of light efficiency.

How to maintain the demand for thinning and improve the light extraction efficiency has become the development focus of the side-emitting type package.

In view of the above, it is a primary object of the present invention to provide a light-emitting device that can more effectively utilize light emitted from a light-emitting diode such as a light-emitting diode to increase the amount of light reaching a light-receiving device such as a light guide plate.

In order to achieve the above object, the present invention provides a light emitting device comprising: a circuit carrier; and a light emitting chip having a plurality of surfaces on the circuit carrier, wherein the light emitting chip comprises: a substrate; a first conductive type semiconductor layer located at On the substrate, an active layer is disposed on the first conductive semiconductor layer; a second conductive semiconductor layer is disposed on the active layer; and a first internal electrode electrically connected to the first conductive type a semiconductor layer; and a second internal electrode electrically connected to the second conductive semiconductor layer; a first reflective layer covering the plurality of surfaces and exposing only any surface of the plurality of surfaces as a light emitting surface; and a first external electrode And a second external electrode is located on the reflective layer, and is electrically connected to the first internal electrode, the second internal electrode, and the circuit carrier, respectively.

The present invention further provides a light emitting device comprising: a circuit carrier; and an illuminating wafer having: a first electrode and a second electrode on the upper surface thereof, and electrically connected via the first electrode and the second electrode Connected to the circuit carrier; a transparent substrate; a first conductive semiconductor layer on the transparent substrate; an active layer on the first conductive semiconductor layer; and a second conductive semiconductor layer Located on the active layer; a reflective layer does not completely cover the surface of the illuminating wafer, leaving an uncovered illuminating surface.

The above and other objects, features, and advantages of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; 1A is a side view showing a relative positional relationship between a light-emitting device and a light-receiving device according to a first embodiment of the present invention, and FIG. 1B is a view showing a light-emitting device according to a first embodiment of the present invention shown in FIG. 1A. Side view of a direction A.

In the first embodiment, the light-emitting device of the first embodiment of the present invention comprises: a circuit carrier 10 and a light-emitting chip 1. In the embodiment, the circuit carrier is a printed circuit board (PCB). The illuminating wafer 1 has a first reflective layer 160 (see FIGS. 2A, 2B) on a side surface 1S4 of the first outer electrode 195 and a second outer electrode 196 on the same side thereof, and via the first outer electrode. The 195 is electrically connected to the circuit carrier 10 and the second outer electrode 196. In the present embodiment, the illuminating wafer 1 is disposed on a side surface of a light-receiving device such as a light guide plate 80 with a predetermined light-emitting surface, so that the light emitted from the luminescent wafer 1 is transmitted to the light guide plate 80. In this embodiment, the circuit carrier 10 and the first outer electrode 195 are electrically connected by a solder ball 11 and the circuit carrier 10 and the second are electrically connected by a soft solder ball 12 . The outer electrode 196 can be used to control whether to illuminate or adjust the brightness of the illuminating wafer 1 by using some control elements (not shown) on the circuit carrier 10; in other embodiments, other suitable Techniques for achieving electrical connection between the first outer electrode 195, the second outer electrode 196, and the circuit carrier 10, such as wire bonding technology, tape automatic bonding (TAB) technology, or Other suitable joining techniques.

FIG. 1B shows that three light-emitting wafers 1 are electrically connected to the circuit carrier 10, and light is supplied to the light guide plate 80. However, for those of ordinary skill in the art to which the present invention pertains, the number, type, arrangement, and the like of the light-emitting wafers 1 can be arbitrarily adjusted according to the needs thereof.

2A and 2B, wherein FIG. 2A is a cross-sectional view showing an example of a light-emitting chip in the light-emitting device according to the first embodiment of the present invention, and FIG. 2B is a first embodiment of the present invention shown in FIG. 2A. A schematic top view of the upper surface of the light-emitting chip in the light-emitting device of the example.

In the second and second embodiments, the luminescent wafer 1 further includes a substrate 100, a first conductive semiconductor layer 120, an active layer 130, a second conductive semiconductor layer 140, and a first internal electrode. 151, and a second inner electrode 152. The first conductive semiconductor layer 120 is on the substrate 100; the active layer 130 is on the first conductive semiconductor layer 120; and the second conductive semiconductor layer 140 is on the active layer 130. In the present embodiment, the "first conductivity type" is an n-type and the "second conductivity type" is a P-type; and in another embodiment, the "first conductivity type" is a P-type, and the above The "second conductivity type" is an n-type. Depending on the wavelength of the light to be emitted, etc., different material combinations may be selected as the first conductive semiconductor layer 120, the active layer 130, and the second conductive semiconductor layer 140, and the material may be selected from the group consisting of aluminum (Al). Semiconductor materials such as gallium (Ga), indium (In), nitrogen (N), phosphorus (P) or arsenic (As), such as aluminum indium gallium nitride (AlGaInN) series materials, aluminum gallium indium phosphide ( AlGaInP) series materials or aluminum gallium arsenide (AlGaAs) series materials.

Also in the second and second embodiments, the first inner electrode 151 is electrically connected to the first conductive semiconductor layer 120, the second inner electrode 152 is electrically connected to the second conductive semiconductor layer 140, and the upper surface of the light emitting wafer 1 is exposed. . Further, the light-emitting wafer 1 has an upper surface 1U, a lower surface 1D, and four side surfaces 1S1, 1S2, 1S3, and 1S4. If the shape of the illuminating wafer 1 is other polyhedrons, the number of side surfaces thereof may vary depending on the needs of those skilled in the art to practice the present invention. In this embodiment, the upper surface 1U of the luminescent wafer 1 is stepped to expose a portion of the first conductive semiconductor layer 120, and the first internal electrode 151 is located on the first conductive semiconductor layer 120 and electrically connected thereto. The second internal electrode 152 is located on the second conductive type semiconductor layer 140 and electrically connected thereto. In other embodiments, other different structural designs may be made to achieve the first internal electrode 151 and the first conductive type semiconductor. The electrical connection of the layer 120 and the electrical connection of the second inner electrode 152 and the second conductive semiconductor layer 140 are electrically connected.

In the present embodiment, the first reflective layer 160 is located on all side surfaces 1S1, 1S2, 1S3, and 1S4 of the light-emitting wafer 1, wherein the side surfaces include the first conductive semiconductor layer 120, the active layer 130, and the second surface. The side surface of the conductive semiconductor layer 140. The following embodiments are also the same. In the embodiment, the first reflective layer 160 is preferably a Distributed Bragg Reflector (DBR).

The first outer electrode 195 shown in FIG. 2B is electrically connected to the first inner electrode 151 via a first circuit layer 191 on the first reflective layer 160; the second outer electrode 196 is located in the first reflective layer 160. A second circuit layer 192 is electrically connected to the second inner electrode 152. The first outer electrode 195 and the second outer electrode 196 may be disposed on the side surface of the same side of the light-emitting wafer 1 via the winding design of the appropriate first wiring layer 191 and the second wiring layer 192 (in this embodiment, The side surface 1S4) is attached to the light-emitting wafer 1 to the circuit carrier 10 (refer to FIGS. 1A and 1B) and electrically connected thereto.

In the winding design employed in the present embodiment, as shown in FIG. 2B, the first wiring layer 191 extends from the first inner electrode 151 of the upper surface 1U to the first reflective layer 160 on the side surface 1S1. And extending to the first reflective layer 160 on the side surface 1S4; the second circuit layer 192 starts from the second inner electrode 152 of the upper surface 1U, extends to the first reflective layer 160 on the side surface 1S2, and then extends to The first reflective layer 160 on the side surface 1S4. The winding method described above is merely an example, and those skilled in the art to which the present invention pertains may adopt a winding method suitable for the scope of application thereof when implementing the present invention.

In the embodiment shown in FIG. 2A, the substrate 100 is a transparent substrate such as a sapphire substrate, and the upper surface 1U serves as a light-emitting surface of the light-emitting wafer 1. At this time, a second reflective layer 170 needs to be additionally disposed to cover the lower surface 1D of the luminescent wafer 1, wherein the second reflective layer 170 may be a metal reflective layer or a distributed Bragg mirror. In another embodiment, the substrate 100 may be a substrate having light reflectivity, such as a copper substrate or an aluminum substrate. In addition, the first conductive semiconductor layer 120 and the substrate 100 may further include a bonding layer.

In the above embodiment, light is emitted from the active layer 130, and light rays reaching the side surfaces 1S1, 1S2, 1S3, 1S4 and the lower surface 1D are reflected to the upper surface 1U, and light is emitted from the upper surface 1U. When the light-emitting wafer 1 shown in FIG. 2A is electrically connected to the circuit carrier 10 shown in FIGS. 1A and 1B, the upper surface 1U is a light-emitting surface facing the side surface of the light guide plate 80, and the light can be efficiently radiated. Provided to the light guide plate 80. Therefore, with the light-emitting device of the first embodiment of the present invention, the light is emitted from only one light-emitting surface by the above structure, thereby preventing or greatly reducing the light loss caused by light leakage (the light is dissipated to the region where the light-receiving device cannot receive light). In this case, the use efficiency of the light emitted by the light-emitting device in the light-emitting device can be improved.

As described above, different material combinations may be selected as the first conductive type semiconductor layer 120, the active layer 130, and the second conductive type semiconductor layer 140 depending on the wavelength of the light to be emitted or the like. For example, when the light guide plate 80 shown in FIG. 1A needs white light, one method is to make the three light-emitting chips 1 arranged in FIG. 1B respectively emit light of three primary colors of red, green and blue, and combine them into white light to provide Light guide plate 80. Another method is to provide white light by a single illuminating wafer 1, for example, the illuminating wafer 1 in the illuminating device of the first embodiment of the present invention emits ultraviolet light or blue light, and the emitted light is transmitted through a suitably disposed wavelength conversion layer. And converted into white light.

An example of a wavelength conversion layer setup is shown in Figure 3. Compared with the luminescent wafer 1 shown in FIG. 2A, except that a wavelength conversion layer 110 is disposed between the first conductive semiconductor layer 120 and the substrate 100, the wavelength conversion layer 110 has a wavelength converting substance. The bonding layer, the components, the configuration, the connection relationship, and the like of the light-emitting wafer 1 shown in Fig. 3 are the same as those shown in Fig. 2A. When the illuminating wafer 1 shown in FIG. 3 is a blue illuminating wafer, the wavelength converting substance of the wavelength converting layer 110 contains a yellow luminescent powder, and a part of the blue light passing through the wavelength converting layer 110 can be converted into yellow light due to blue color. Yellow is a complementary color, and the converted yellow light and other blue light can be combined to provide white light to the light guide plate 80 shown in FIGS. 1A and 1B. In another case, when the illuminating wafer 1 shown in FIG. 3 is also a blue illuminating wafer, the wavelength converting layer 110 has a green luminescent phosphor and a red luminescent phosphor, and the blue ray passing through the wavelength conversion layer 110 A part of the light can be converted into green light and red light. Since red, green and blue are the three primary colors, the converted green light, red light and other blue light can be combined into white light to be supplied to the light guide plate 80 shown in FIGS. 1A and 1B. In another case, when the illuminating wafer 1 shown in FIG. 3 is an ultraviolet illuminating wafer, the wavelength converting layer 110 may have a blue fluorescing powder, a green luminescent powder, and a red luminescent powder. The ultraviolet light passing through the phosphor layer 110 can be converted into blue light, green light, and red light. Since red, green, and blue are the three primary colors, the converted blue light, green light, and red light can be synthesized into white light and provided to the first and second images. Light guide plate 80 is shown.

In another embodiment, as shown in FIG. 4, the first reflective layer 160 and the second reflective layer 170 are respectively covered by a dielectric film 161/163, 171/173, and a metal reflective layer 162, 172. The sandwich structure has a dielectric film 161, 163, 171, 173 made of a transparent insulating material; in other words, the dielectric film 161 is located between the metal reflective layers 162, 172 and the luminescent wafer 1. In this embodiment, the metal reflective layer 162 is sufficiently electrically isolated from the first conductive semiconductor layer 120, the active layer 130, the second conductive semiconductor layer 140, and the first wiring layer 191 and the second wiring layer 192. Avoid short circuits.

FIG. 5 is another embodiment of the present invention. As shown in FIG. 5, the second reflective layer 180 covers the upper surface 1U of the luminescent wafer 1, but does not cover the first inner electrode 151 and the second inner electrode 152. The first reflective layer 160 covers the side surface 1S1/1S2 of the light-emitting chip, and only the lower surface 1D of the light-emitting chip 1 is exposed. The first reflective layer 180 and the second reflective layer 170 may be distributed Bragg mirrors in this embodiment. Or a sandwich film formed by a dielectric film covering a metal reflective layer. In the present embodiment, the substrate 100 is a transparent substrate, such as a sapphire substrate, and the lower surface 1D is a light-emitting surface. When the light-emitting wafer 1 shown in FIG. 5 is electrically connected to the circuit carrier 10 shown in FIGS. 1A and 1B, the lower surface 1D which is the light-emitting surface is the side surface facing the light guide plate 80, and the light is efficiently applied. Provided to the light guide plate 80.

Next, please refer to FIG. 6, which is a side view of a light-emitting device and a relative positional relationship thereof with a light-receiving device according to a second embodiment of the present invention.

In Fig. 6, a light-emitting device according to a second embodiment of the present invention comprises: a circuit carrier 20 and a light-emitting chip 2. The illuminating chip 2 has a first inner electrode 251 and a second inner electrode 252, and is electrically connected to the circuit carrier 20 via the first inner electrode 251 and the second inner electrode 252. In this embodiment, the illuminating chip 2 faces a light receiving device, such as a side surface of a light guide plate 90, with a predetermined light emitting surface, so that the light emitted by the luminescent wafer 2 is transmitted to the light guide plate 90, wherein the circuit carrier 20 A soft solder ball 21 is electrically connected to the first inner electrode 251, and a soft solder ball 22 is electrically connected between the circuit or body 20 and the second inner electrode 252. This can use some control elements (not shown) on the circuit carrier 20 to control whether the illuminating chip 2 is illuminated or adjust its brightness, etc.; in other embodiments, other suitable techniques can be used to achieve the first Electrical connection between the inner electrode 251, the second inner electrode 252 and the circuit carrier 20, such as wire bonding techniques, tape and tape automated bonding techniques, or other suitable bonding techniques. In addition, in this embodiment, the three light-emitting chips 2 are electrically connected to the circuit carrier 20 to provide light to the light guide plate 90. However, for those having ordinary knowledge in the technical field of the present invention, the light-emitting chip can be arbitrarily adjusted according to the needs thereof. The number, type, arrangement, etc. of 2.

Next, please refer to FIG. 7, which is a cross-sectional view of a light-emitting chip in a light-emitting device according to a second embodiment of the present invention.

In FIG. 7, the luminescent wafer 2 further includes a substrate 200, a first conductive semiconductor layer 220, an active layer 230, a second conductive semiconductor layer 240, a first internal electrode 251, and a second The internal electrode 252 has a structure, a material, a connection relationship, and the like, respectively, and the substrate 100, the first conductive semiconductor layer 120, the active layer 130, the second conductive semiconductor layer 140, and the first internal electrode 151 shown in FIG. The second internal electrode 152 is equivalent or identical, and the details thereof can be referred to the description of FIG. 2A before, and therefore will be omitted.

Also in Fig. 7, the luminescent wafer 2 has an upper surface 2U, a lower surface 2D and four side surfaces. However, only the two side surfaces 2S1, 2S2 are shown in Fig. 7. If the shape of the light-emitting wafer 2 is other polyhedrons, the number of side surfaces thereof may vary depending on the needs of those skilled in the art to practice the present invention. Further, the first reflective layer 260 covers the side surface of the light-emitting wafer 2 leaving only a light-emitting surface uncovered, and the second reflective layer 270/270' covers the upper surface 2U and the lower surface 2D, respectively. In the present embodiment, the first reflective layer 260 covers only the side surface 2S2 and the two side surfaces not shown, and does not cover the side surface 2S1, and the side surface 2S1 becomes the light-emitting surface of the light-emitting wafer 2. The forming method and material of the first reflective layer 260 and the second reflective layer 270/270' are substantially the same as the first reflective layer 160 described above, but the side surface 2S1 needs to be masked or formed after the formation, for example, etching or Other techniques remove the reflective layer formed on the side surface 2S1.

In the embodiment shown in FIG. 7, the flip-chip technique is adhered to the circuit carrier 20 shown in FIG. 6 to be electrically connected thereto, and the side surface 2S1 as the light-emitting surface faces the side of the light guide plate 90. The surface does not require the structure of the outer electrode in the foregoing first embodiment and the wiring layer for winding. In addition, in another embodiment, the substrate 200 may be an opaque substrate or a reflective substrate, such as a ruthenium substrate. In this case, it is not necessary to provide the second reflective layer 270' on the lower surface 2D of the luminescent wafer 2.

When the light-emitting wafer 2 shown in FIG. 7 is electrically connected to the circuit carrier 20 shown in FIG. 6, the side surface 2S1 is a light-emitting surface facing the side surface of the light guide plate 90, effectively providing light to the guide. Light board 90. Therefore, according to the illuminating device of the second embodiment of the present invention, the light is emitted from only one illuminating surface by the above structure, and the light loss caused by light leakage (the area where the light is dissipated to the light collecting device cannot be received) can be prevented or greatly reduced. In this case, the use efficiency of the light emitted by the light-emitting device in the light-emitting device can be improved.

As described above, according to the light-emitting device of each embodiment of the present invention, the light emitted from the light-emitting chip such as the light-emitting diode can be more effectively utilized, and the amount of light reaching the light-receiving device such as the light guide plate can be increased, thereby achieving the above-mentioned The object of the invention.

Although the present invention has been disclosed in the above preferred embodiments, the present invention is not intended to limit the invention, and it is possible to make a few changes without departing from the spirit and scope of the invention. And the scope of the present invention is defined by the scope of the appended claims.

1. . . Light emitting chip

1D. . . lower surface

1S1. . . Side surface

1S2. . . Side surface

1S3. . . Side surface

1S4. . . Side surface

1U. . . Upper surface

2. . . Light emitting chip

2D. . . lower surface

2S1. . . Side surface

2S2. . . Side surface

2U. . . Upper surface

10. . . Brush board

11. . . Soft solder ball

12. . . Soft solder ball

20. . . Circuit carrier

twenty one. . . Soft solder ball

twenty two. . . Soft solder ball

80. . . Light guide

90. . . Light guide

100. . . Substrate

110. . . Fluorescent layer

120. . . First conductive semiconductor layer

130. . . Active layer

140. . . Second conductive semiconductor layer

151. . . First inner electrode

152. . . Second inner electrode

160. . . First reflective layer

161. . . Dielectric film

162. . . Metal reflective layer

163. . . Dielectric film

170. . . Second reflective layer

171. . . Dielectric film

172. . . Metal reflective layer

173. . . Dielectric film

180. . . Second reflective layer

191. . . First circuit layer

192. . . Second circuit layer

195. . . First outer electrode

196. . . Second outer electrode

200. . . Substrate

210. . . Wavelength conversion layer

220. . . First conductive semiconductor layer

230. . . Active layer

240. . . Second conductive semiconductor layer

251. . . First inner electrode

252. . . Second inner electrode

260. . . First reflective layer

270. . . Second reflective layer

270’. . . Second reflective layer

Fig. 1A is a side view showing the light-emitting device of the first embodiment of the present invention and its relative positional relationship with a light-receiving device.

Fig. 1B is a side view showing the light-emitting device of the first embodiment of the present invention shown in Fig. 1A in the other direction A.

Fig. 2A is a cross-sectional view showing an example of a light-emitting chip in the light-emitting device of the first embodiment of the present invention.

Fig. 2B is a plan view showing the upper surface of the light-emitting wafer in the light-emitting device according to the first embodiment of the present invention shown in Fig. 2A.

Fig. 3 is a cross-sectional view showing a modification of the light-emitting chip in the light-emitting device of the first embodiment of the present invention.

Fig. 4 is a cross-sectional view showing another modification of the light-emitting chip in the light-emitting device of the first embodiment of the present invention.

Fig. 5 is a cross-sectional view showing still another modification of the light-emitting chip in the light-emitting device of the first embodiment of the present invention.

Figure 6 is a side elevational view showing the light-emitting device of the second embodiment of the present invention and its relative positional relationship with a light-receiving device.

Fig. 7 is a cross-sectional view showing an example of a light-emitting chip in a light-emitting device according to a second embodiment of the present invention.

1. . . Light emitting chip

1D. . . lower surface

1S1. . . Side surface

1S2. . . Side surface

1U. . . Upper surface

100. . . Substrate

120. . . First conductive semiconductor layer

130. . . Active layer

140. . . Second conductive semiconductor layer

151. . . First inner electrode

152. . . Second inner electrode

160. . . First reflective layer

170. . . Second reflective layer

191. . . First circuit layer

192. . . Second circuit layer

Claims (10)

A light-emitting device comprising: a circuit carrier; a light-emitting chip having a plurality of surfaces on the circuit carrier, wherein the light-emitting chip comprises: a first conductive semiconductor layer; and an active layer located in the first conductive semiconductor layer a second conductive semiconductor layer on the active layer; a first internal electrode electrically connected to the first conductive semiconductor layer; a second internal electrode electrically connected to the second conductive semiconductor layer; a reflective layer covering the plurality of surfaces and exposing only one of the plurality of surfaces as a light-emitting surface; and a first outer electrode and a second outer electrode are disposed on the reflective layer, respectively, and the first inner electrode a second internal electrode, and the circuit carrier is electrically connected; and a light guide plate, wherein a light emitting surface of the light emitting chip faces a side of the light guide plate. The illuminating device of claim 1, further comprising a first circuit layer and a second circuit layer for electrically connecting the first inner electrode and the first outer electrode and the second inner electrode And the second outer electrode. The illuminating device of claim 1, further comprising a substrate under the first conductive semiconductor layer and a wavelength conversion layer between the first conductive semiconductor layer and the substrate. The illuminating device of claim 3, wherein the illuminating wafer is a blue illuminating wafer, and the wavelength converting layer has a yellow luminescent phosphor. The illuminating device of claim 3, wherein the illuminating device The optical wafer is a blue light emitting chip, and the wavelength conversion layer has a green fluorescent powder and a red fluorescent powder. The illuminating device of claim 3, wherein the illuminating wafer is an ultraviolet illuminating wafer, and the wavelength converting layer has a blue luminescent powder, a green luminescent powder and a red luminescent powder. The illuminating device of claim 1, wherein the reflective layer is a metal reflective layer. The illuminating device of claim 1, wherein the reflective layer is a distributed Bragg mirror. The illuminating device of claim 1, further comprising: a first soft solder ball electrically connected to the circuit carrier and the first outer electrode; and a second soft solder ball, electrically The circuit carrier and the second outer electrode are connected. A light-emitting device comprising: a circuit carrier; a light-emitting chip having a plurality of surfaces on the circuit carrier, wherein the light-emitting chip comprises: a substrate; a light-emitting layer on the substrate; at least one electrode, respectively electrically Connecting the light-emitting layer and the circuit carrier; and a reflective layer covering the plurality of surfaces and exposing only one of the plurality of surfaces as a light-emitting surface; and a light guide plate, wherein the light-emitting surface of the light-emitting chip a side surface of the light guide plate; wherein the reflective layer covers the substrate and the light On the side of the laminate.