TWI393280B - Light-emitting device with magnetic field - Google Patents

Description

Magnetic illuminating device

The present invention relates to a light emitting device, and more particularly to a magnetic light emitting device.

A light emitting device such as a Light Emitting Diode (LED) can emit light depending on the driving electron flow through the active layer of the LED. However, if the current density distributed throughout the light-emitting region is uniform, the uniformity of light emission is lowered. Still further, in conventional designs, the opaque top electrode is typically disposed in a central region of the illuminating region. According to the above, the current density under the top electrode is larger than other regions and more light can be emitted. However, based on the top electrode being opaque, the illumination below the top electrode is covered. Since the top electrode of a conventional LED covers the highest intensity illumination in the central region, the output brightness is reduced.

Accordingly, in the related art, improvement of LED light-emitting output efficiency still needs further development.

The present invention provides a light emitting device having a magnetic source. The light emitting device includes a light emitting stack structure. The light emitting stacked structure has a first electrode, a second electrode, an upper doped stacked layer, a bottom doped stacked layer, and an active layer interposed between the upper doped stacked layer and the bottom doped stacked layer. The first electrode and the second electrode are disposed on the same side of the light emitting stack structure and configured to provide a driving current. The magnetic source layer is used to provide a magnetic field to the light emitting stack structure, the direction of the magnetic field being substantially perpendicular to the upper doped stacked layer.

The present invention provides a light emitting device having a magnetic source, comprising a light emitting stack structure. The light emitting stack structure has first and second electrodes distributed on the same side of the light emitting stack structure. The magnetic source layer is bonded to the light emitting stack structure to provide a magnetic field to the light emitting stack structure, wherein the direction of the magnetic field is substantially perpendicular to the light emitting stack structure.

The present invention provides a method of increasing the luminous efficacy of a light emitting device, wherein the method includes applying a magnetic field substantially perpendicular to the direction of the light emitting region of the light emitting device.

The foregoing general description and the following detailed description are exemplary and are in the

The accompanying drawings included in the present specification are intended to provide a more obvious understanding of the invention and The drawings illustrate various exemplary embodiments of the invention, and are in accordance

The present invention provides a light-emitting device for applying a magnetic field perpendicularly, thereby increasing light output efficiency. Many exemplary embodiments are described to illustrate the invention, but the invention is not limited to a plurality of exemplary embodiments. Still further, combinations of various exemplary embodiments may be utilized to form other exemplary embodiments.

In the physical phenomenon, the Hall effect is that when a current flows through the wire and a magnetic field is applied laterally, then, for example, the current path of the electron current is laterally shifted based on the magnetic field Lorenz force of F=q*v*B. The present invention incorporates a Hall effect into an LED in accordance with the principles of the Hall effect.

1 illustrates a cross-section of a magnetic LED structure in accordance with an exemplary embodiment of the present invention. In Fig. 1, an LED is taken as an example. For example, the LED includes a bottom electrode 100, a light emitting structure 102, and a top electrode 104, and the light emitting structure 102 includes a first semiconductor structure layer 102a, an active layer 102b, and another semiconductor structure layer 102c, wherein the first semiconductor structure layer 102a For example, a P-type doped semiconductor structure layer, the active layer 102b for emitting light is a combination of electrons and holes, and the other semiconductor structure layer 102c is, for example, an N-type doped layer. The top electrode 104 may not be disposed in the center of the light emitting region 180.

When operating, current flows from the bottom electrode 100 to the top electrode 104. however. If a magnetic field is applied laterally in one direction, such as indicated by magnetic field 106, a Lorenz force is generated to deflect and extend the current. Taking FIG. 1 as an example, according to the same concept, the conductivity type of the electrode and the direction of the magnetic field can be changed according to the actual design. Accordingly, the current can be laterally offset and flow from the bottom electrode to the top electrode. The driving current can more efficiently illuminate the active layer 102b.

As shown in the structure of FIG. 1, the two electrodes 100 and 104 are located on opposite sides of the light emitting structure 102, and then the direction of the applied magnetic field is parallel to the light emitting region 180, wherein the drive current is offset within the light emitting structure 102. However, when the electrodes are disposed on the same side of the light-emitting structure, a large amount of current in the horizontal portion is generated, and the direction of the magnetic field must be changed correspondingly.

2A and 2B illustrate top views of a physical process of a magnetic field in a light emitting diode structure in accordance with an exemplary embodiment of the present invention. Referring to FIG. 2A, the light emitting structure 200 is rectangular, and the two electrodes 202 and 204 are located on the diagonal side. When given At the appropriate voltage, the current 206 is concentrated in the region of the shortest path, so that the current density is not uniform. Referring to FIG. 2B, when the magnetic field 208 is applied in a direction of a magnetic field, such as perpendicular to the direction of the light emitting structure 200, the Lorenz force causes the flow direction of the current 206 to be changed. Accordingly, the current 206 can be spread and evenly distributed throughout the entire area of the light emitting structure 200. This means that the illuminating area can be increased and not concentrated in a certain area. However, the position of the electrode 204 will change correspondingly according to the applied magnetic field.

3 through 4 illustrate improvements in the application of a magnetic field to a light emitting device in accordance with an exemplary embodiment of the present invention. Referring to Figure 3, the research data shows that the output power can be increased when a magnetic field is applied. The curve with diamond dots represents the output power without a magnetic field, while the curve with dots represents the output power with a magnetic field of 0.05 Tesla. The improvement in output power can also be observed from the injection current. In Fig. 4, the curve of the applied magnetic field has the same large output power. In other words, the physical process of Figure 2 can actually improve the output power. In accordance with the physical processes presented by the present invention, a plurality of exemplary embodiments can be implemented in accordance with different design requirements. However, the present invention is not limited to the exemplary embodiments. Further combinations of the various exemplary embodiments may be combined to form other exemplary embodiments.

5 through 9 illustrate cross-sectional views of a light emitting device structure in accordance with various exemplary embodiments of the present invention. Referring to FIG. 5, the light emitting structure includes a basic structure 264 disposed on the substrate 252. The basic structure can include, for example, a bottom doped layer 254, wherein the bottom doped layer 254 can be an organic, inorganic semiconductor, or any doped material suitable for luminescence. The base structure 264 can include, for example, a bottom doped stacked layer 254, an active layer 256 (which produces photons), and an upper doped stacked layer 258. Here, the bottom doped stacked layer 254 or the upper doped stacked layer 258 For different conductive types. However, depending on the operating voltage, the bottom doped stacked layer 254 or the upper doped stacked layer 258 may be P-type or N-type. In addition, for example, the contact capability of the electrode based on the doped semiconductor material is relatively insufficient, which may further include, for example, a transparent conductive layer (TCL) 260 for increasing the current in the upper doped stacked layer 258. Current spreading effect. On the other hand, to obtain a better light output at the light emitting region 270, the rough surface 262 may be formed, for example, over the TCL 260 or the upper doped stacked layer 258. In fact, the rough surface 262 can be disposed on any suitable surface depending on the light output face. The bottom doped stacked layer 254 and the upper doped stacked layer 258 are respectively disposed. The two electrodes 266 and 268 are located on the same side of the light emitting structure, and such a configuration is referred to as a horizontal-type light emitting diode.

In the present invention, the substrate 252 additionally implements the magnetic source layer 250 on the other side. According to the physical process shown in FIG. 2B, the magnetic source layer 250 is used to generate a magnetic field to redistribute the current density of the horizontal portion to a transparent conductive (TCL) 260. The magnetic source layer 250 can be, for example, a natural magnet to provide a magnetic field substantially perpendicular to the illuminating region 270 and redistribute the current density of the horizontal portion. The electrodes 266 and 268 are disposed at corresponding positions corresponding to the generated magnetic field. The magnetic source layer 250 is used to generate a predetermined magnetic field to offset the drive current, and any suitable improved design can be implemented. The magnetic source layer 250 can also be another substrate. Still further by way of example, the magnetic source layer 250 can be an additional structure that does not require physical contact. In other words, the magnetic source layer 250 can be an external unit for applying a magnetic field or an integrated structural layer in the light emitting structure.

According to the same concept of the physical process, the structure shown in Fig. 5 can be improved, for example, as shown in Fig. 6. Referring to FIG. 6, the substrate 252 of FIG. 5 may be replaced with a reflective layer 272. The reflective layer 272 can be, for example, a metal layer or a reflective material made by other means. Still further, the reflective layer 272 of FIG. 7 can be replaced with, for example, an insulating layer 274. The substrate-compatible reflective layer 272 or the insulating layer 274 may be a substrate having a reduced thickness. The various exemplary embodiments shown in Figures 5 through 7 are for illustrative purposes only. The invention is not limited to the above exemplary embodiments.

In the above exemplary embodiment, the magnetic source layer 250 is implemented at the bottom. However, the magnetic source layer 250 can also be implemented on the top. Since the upper side surface of the light-emitting structure is generally not flat, the magnetic source layer can then be implemented, for example, by means of a package.

Referring to FIG. 8, the magnetic source layer 284 can be implemented by using conventional solder bumps 280 and 282 and a flip chip packaging process. Here, based on the direction in which the light-emitting output is directed toward the light-transmitting substrate 252, the rough surface 262 may be formed on the outer surface of the substrate 252, and the reflective layer 260' such as a metal layer may be implemented on the basic structure 264', however this is not implemented. The only way to package the magnetic source layer 284.

On the other hand, exemplary embodiments may, for example, omit solder bumps 280 and 282, and process electrodes 266 and 268 may be plated or of any suitable semiconductor process and have the same height. Since the electrodes 266 and 268 have the same height, the manner in which the magnetic source layer 284 is subsequently disposed may, for example, be attached to the electrodes. In other words, the magnetic source layer 284 can be formed in any suitable manner.

For further exemplary embodiments, reference may be made to FIG. 8. The structure shown in FIG. 8 may be combined with the magnetic source layer 250 at the bottom of the structure shown in FIG. 5, whereby two magnetic source layers are implemented.

In Fig. 9, another embodiment is to view the magnetic source layer 284 as a substrate. In this case, the basic structure 264'' can be packaged with the magnetic source layer 284 as described above. Similar to Figure 8, reflective layer 260' is implemented in basic structure 264''. In addition to this, the bottom doped layer 254 has a rough surface 262. Accordingly, light can pass through the rough surface 262 for better performance.

As before, the various exemplary embodiments described above are for illustrative purposes only, and all of the exemplary embodiments can be combined to form other exemplary embodiments.

The position where the electrodes are provided will be described later.

10 through 11 illustrate top views of a structure of a light emitting device for arranging electrodes in accordance with various exemplary embodiments of the present invention. Referring to FIG. 10, in the design of the light emitting device 300, the two electrodes 302 and 304 for connecting the upper and bottom doped stacked layers may have a line pattern. However, in the plan view, the two-line pattern is partially interleaved. Under this electrode structure, the two electrodes 302 and 304 are not completely symmetrical. In an exemplary embodiment, the gap distance between the two branch lines of the two line patterns is not as consistent as the selectivity constant. Referring to Figure 11, in another design, electrodes 306 and 308 are not disposed on a diagonal. The manner in which the electrodes are arranged is designed according to the applied magnetic field. The strength and direction of the magnetic field can cause different effects. In detail, if a magnetic field is applied as shown in FIG. 2A in FIG. 11, the electrode 306 corresponds to the magnetic field and is not in a symmetrical position.

According to the electrode configuration shown in Figs. 10 and 11, the research data can be completed. For example, a 420 millitesla magnetic field in the vertical direction and a current of 200 milliamps are applied. The structure shown in Fig. 10 can increase the output power by about 12% compared to the case where no magnetic field is applied. An output power of about 5.6% can be increased in FIG. According to the research data, according to the position of the electrode configuration, the additional magnetic field of the present invention can actually enhance the performance.

From another aspect of the method of operation, the present invention provides a method of increasing the luminous efficacy of a light emitting device, wherein the method includes applying a magnetic field substantially perpendicular to the direction of the light emitting region of the light emitting device. According to an exemplary embodiment, the manner in which the magnetic field is applied may include integrating the magnetic source layer to the light emitting device, wherein the magnetic source layer generates a magnetic field. In another exemplary embodiment, the magnetic field can be applied externally.

While the present invention has been described above by way of exemplary embodiments, it is not intended to limit the invention, and it is to be understood by those skilled in the art without departing from the spirit and scope of the invention. The teachings, disclosures, or stipulations of the invention are subject to a few changes and modifications, and the scope of the invention is defined by the scope of the appended claims.

100‧‧‧ bottom electrode

102,200‧‧‧Lighting structure

102a, 102c‧‧‧ semiconductor structural layer

102c, 256‧‧‧ active layer

104‧‧‧Top electrode

106, 208‧‧‧ magnetic field

180, 270‧‧‧Lighting area

202, 204, 266, 268, 302, 304, 306, 308 ‧ ‧ electrodes

206‧‧‧ Current

250, 284‧‧‧ magnetic source layer

252‧‧‧Base

254‧‧‧Bottom doped layer

258‧‧‧Upper doped stack

260, 260' ‧ ‧ transparent conductive layer

262‧‧‧Rough surface

264, 264’, 264” ‧‧‧ basic structure

272‧‧‧reflective layer

274‧‧‧Insulation

280, 282‧‧‧ solder bumps

300‧‧‧Lighting device

1 is a cross-sectional view of a structure of a magnetic light emitting diode in accordance with an exemplary embodiment of the present invention.

2A and 2B are top views of a physical process of a magnetic field in a light emitting diode structure in accordance with an exemplary embodiment of the present invention.

3 through 4 are diagrams showing an improvement in the application of a magnetic field to a light-emitting device in accordance with an exemplary embodiment of the present invention.

5 through 9 are cross-sectional views of a structure of a light emitting device in accordance with various exemplary embodiments of the present invention.

10 through 11 are top views of a structure of a light emitting device for arranging electrodes in accordance with various exemplary embodiments of the present invention.

250. . . Magnetic source layer

252. . . Base

254. . . Bottom doped layer

256. . . Active layer

258. . . Upper doped stack

260. . . Transparent conductive layer

262. . . Rough surface

264. . . basic structure

266, 268. . . electrode

270. . . Luminous area

Claims (19)

A light emitting device having a magnetic source, comprising: a light emitting stacked structure having a first electrode, a second electrode, an upper doped stacked layer, a bottom doped stacked layer, and the upper doped stacked layer The bottom layer is doped with an active layer between the stacked layers, wherein the first electrode and the second electrode are disposed on the same side of the light emitting stack structure and configured to provide a driving current; and a magnetic source layer is disposed on the light emitting layer The exterior of the stacked structure is configured to provide a magnetic field to the light emitting stack structure, the direction of the magnetic field being substantially perpendicular to the upper doped stacked layer. The light-emitting device of claim 1, wherein the bottom doped stacked layer has one of an N-type or a P-type conductivity type. The illuminating device of claim 1, further comprising a substrate, wherein the illuminating stack structure is disposed on a first side of the substrate, and the magnetic source layer is disposed on a second side of the substrate. The illuminating device of claim 1, further comprising a reflective layer, wherein the illuminating stack structure is disposed on a front side of the reflective layer, and the magnetic source layer is disposed on a back side of the reflective layer. The illuminating device of claim 1, wherein the upper portion of the upper doped stacked layer of the luminescent stack structure comprises a transparent conductive layer for contacting the first electrode. The illuminating device of claim 5, wherein the transparent conductive layer has a rough surface for increasing a luminous output efficiency. The illuminating device according to claim 1, further comprising a An insulating layer, wherein the insulating layer is disposed on the magnetic source layer, and the light emitting stacked structure is disposed on the insulating layer. The illuminating device of claim 1, further comprising a solder material layer, wherein the magnetic source layer and the luminescent stack structure are packaged to contact the first electrode and the second electrode. The illuminating device of claim 8, further comprising a substrate, wherein the illuminating stack structure is disposed on the substrate. The illuminating device of claim 1, wherein the first electrode has a first line pattern, the second electrode has a second line pattern, and the first line pattern and a portion of the second line pattern The pattern is interleaved in a plurality of regions corresponding to the magnetic field. The illuminating device of claim 10, wherein the line gap between the first line pattern and the plurality of branch lines of the second line pattern is not fixed. The illuminating device of claim 1, wherein the first electrode and the second electrode comprise a dot-like region. The illuminating device of claim 1, wherein the magnetic source layer is a layer of magnetized material having a magnetic force, the magnetic force acting substantially perpendicular to the upper doped stacked layer. The illuminating device of claim 1, wherein the magnetic source layer is not in direct physical contact with the luminescent stack structure. A light-emitting device having a magnetic source, comprising: a light-emitting stack structure having a first electrode and a second electrode distributed on one of the light-emitting output sides of the light-emitting stack structure; A magnetic source layer is coupled to the light emitting stack to provide a magnetic field to the light emitting stack, wherein the direction of the magnetic field is substantially perpendicular to the light emitting stack, wherein the magnetic source layer is an external magnetic source. The illuminating device of claim 15, wherein the magnetic source layer is encapsulated with the luminescent stack structure. The illuminating device of claim 15, wherein the magnetic source layer is a carrier substrate. The illuminating device of claim 15, wherein the magnetic source layer is stacked on one side of the illuminating stack structure. The illuminating device of claim 15, wherein the first electrode and the second electrode are disposed in a plurality of regions corresponding to the magnetic field, whereby a driving region is laterally offset by a driving current.