Patent Application
20200006924
The present invention relates to micro laser diodes, and more specifically, to a micro laser diode display device and an electronics apparatus.
The laser diode (LD) has been actively developed recently. Generally, a laser diode or a laser diode array is used as a light source for optical communications or a laser printer. The laser diode could be of a vertical cavity surface emitting laser (VCSEL) structure, which includes a lower contact layer, a lower Bragg reflector layer, a lower spacer layer, an active layer, an upper spacer layer, an upper Bragg reflector layer and an upper contact layer.
In the prior art, micro laser diodes are transferred onto a receiving substrate individually. The common electrode for the micro laser diodes is mounted at bottom on the receiving substrate. The top electrodes of the laser diodes are wire-bonded onto the receiving substrate. Although the laser diode is downsizing and thus an individual micro laser diode can be made, traditional assembling approaches are still used in transfer of the micro laser diode. They are not suitable for the application of a micro laser diode. Furthermore, they are not suitable for a display device using micro laser diodes, especially, a high definition (HD) display device.
US patent application No. 2016/0308333 A1 discloses a laser diode array, method of manufacturing the same, printer and optical communication device, which is hereby incorporated herein by reference.
Micro-LEDs can be used as display light source. But, they are not suitable for projection display. A projection display apparatus using micro-LEDs requires a complicated optical focusing system, which limits its application.
U.S. Pat. No. 9,367,094 B2 discloses a display module and system applications, which is hereby incorporated herein by reference.
Therefore, there is a demand in the art that a new solution for a display device using micro laser diodes shall be proposed to address at least one of the problems in the prior art.
Therefore, there is a demand in the art that a new solution for display using micro laser diodes shall be proposed to address at least one of the problems in the prior art.
One object of this invention is to provide a new technical solution for a display device using micro laser diodes.
According to a first aspect of the present invention, there is provided a micro laser diode display device, comprising: a substrate, wherein first type electrodes are arranged on the substrate; a micro laser diode array of at least one color bonded on the substrate, wherein a first side of micro laser diodes in the micro laser diode array is connected to the first type electrodes; and second type electrodes connected to a second side of the micro laser diodes.
Alternatively or optionally, the micro laser diodes are of vertical cavity surface emitting laser structure, which includes a lower contact layer, a lower Bragg reflector layer, a lower spacer layer, an active layer, an upper spacer layer, an upper Bragg reflector layer and an upper contact layer.
Alternatively or optionally, dielectric filler layer is filled among the micro laser diodes. Alternatively or optionally, at least one part of the second type electrodes is formed at a lateral side of the micro laser diodes.
Alternatively or optionally, the second type electrodes are formed on top of the micro laser diodes and the dielectric filler layer, and are patterned so that the micro laser diodes are exposed.
Alternatively or optionally, the second type electrodes are common electrodes.
Alternatively or optionally, the at least one color includes red color, blue color and green color.
Alternatively or optionally, the first type electrodes are anodes and the second type electrodes are cathode.
Alternatively or optionally, the micro laser diode display device is a projection display device.
According to a second aspect of the present invention, there is provided an electronics apparatus, comprising the micro laser diode display device according to the present invention as a projection display source.
According to an embodiment of this invention, the present invention can provide a new solution for a display device by using micro laser diodes.
Further features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments according to the present invention with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention.
Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods and apparatus as known by one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all of the examples illustrated and discussed herein, any specific values should be interpreted to be illustrative only and non-limiting. Thus, other examples of the exemplary embodiments could have different values.
Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it is possible that it need not be further discussed for following figures.
Embodiments and examples of the present invention will be described with reference to the drawings.
As shown in
For example, the micro laser diode 100 can be mounted on a lower metal electrode 108.
In
The micro laser diode display device further comprises a micro laser diode array of at least one color 200r, 200g, 200b and second type electrodes 211. The micro laser diode array is bonded on the substrate 213. The first side (lower side) of micro laser diodes 200r, 200g, 200b is connected to the first type electrodes 214, for example, via a bonding layer 215. The second type electrodes 211 are connected to a second side of the micro laser diodes 200r, 200g, 200b.
For example, the micro laser diodes can be of VCSEL structure as shown in
For example, the first type electrodes are anodes and the second type electrodes are cathode.
For example, the diameter of the micro laser diodes may be 1-500 μm, preferably 10-100 μm and further preferably 20-50 μm. In an example, the diameter of the micro laser diodes may be less than 100 μm.
In the prior art, a laser diode is not used in a display device. In this invention, it is used for display. For example, the micro laser diode display device can be a projection display device and it is used as a light source of a projector. It can project light onto a display screen (display surface). Because of the highly collimated light emitted by the micro laser diodes, it can offer a focus-free display. Compared with a micro-LED projection display device requiring a complicated optical focusing system due to its limited focal depth, the display solution using micro laser diodes will have advantages. This will lead to a new technical trend for display different from that of micro-LED.
As shown in
In an example, as shown in
In another example, as shown in
Alternatively, the second type electrodes 311 may be transparent and is un-patterned. This will simplify the manufacturing of the device.
The second type electrodes can be a common electrode and/or be shorted.
It would be understood by a person skilled in the art that although the above two examples are shown in one figure, they can be implemented separately or in combination.
As shown in
As shown in
The micro laser diode display device according to the embodiments of the present invention can used in an electronics apparatus as a projection display source. The electronics apparatus can be a projector, a projection television, a smart phone with projection display and so on.
Below, a method for transferring micro laser diodes will be described with reference to
As shown in
A first side (lower side) of the micro laser diodes 500r on a carrier substrate 520 is brought into contact with the bonding layer 514. The carrier substrate 520 is laser-transparent.
In
Selected micro laser diodes 500r are irradiated with laser 521 from the side of the carrier substrate 520 to lift-off the selected micro laser diodes 500r from the carrier substrate 520.
For example, during lifting-off, the micro laser diodes 500r are kept on the receiving substrate 513 through a gravity force. Alternatively, an adhesion force of the bonding layer 515 may also be used to keep the micro laser diodes 500r. Further alternatively, an electrostatic force may be applied to the micro laser diodes 500r to keep it on the receiving substrate 513. Even further alternatively, an electromagnetic force may be applied to the micro laser diodes 500r to keep it on the receiving substrate 513. The above approaches can be used individually or in any combination.
This embodiment proposes a new approach for transferring micro laser diodes. Compared with the prior solution of picking up laser diodes individual with a pick-up head, this embodiment is more suitable for semiconductor processing. For example, it can improve yield. Optionally, it can provide a more efficient transfer. Optionally, the definition of the micro laser diodes may be improved.
As shown in
After transferring, the bonding layer 515 may be cured.
As shown in
This processing may provide flexibility for a designer or a manufacturer in designing and manufacturing a micro laser diodes device.
As shown in
For example, during the second type electrodes 511 are formed, an electrode layer are formed on the micro laser diodes 500r, 500g, 500b and the dielectric filler layer 512. Then, the electrode layer is patterned to expose the micro laser diodes to form the second type electrodes 511.
Alternatively, the electrode layer is transparent and may not be patterned. This will simplify the manufacture processing and thus may reduce the cost.
Although it is not shown, at least one part of the second type electrodes 511 may be formed at a lateral side of the micro laser diodes 500r, 500g, 500b.
For example, the second type electrode 511 may be a common electrode.
For example, the first type electrodes 514 are anodes and the second type electrodes 511 are cathode.
For example, the diameter of the micro laser diodes 500r, 500g, 500b may be less than 100 μm.
For example, a protection layer may be applied on the top of the transferred micro laser diodes.
In another embodiment, a method for manufacturing a micro laser diode device may include transferring micro laser diodes to a receiving substrate of the micro laser diode device by using the method according to any of the embodiments of the present invention.
For example, the manufacturing method can be used to manufacture the micro laser diode display device according to the embodiments of the present invention. Alternatively, the method can further be used in manufacturing a micro laser diode device, and the micro laser diode device may be used in micro laser printers, optical communications, collimated light sourcing, micro-displays, micro-projections and so on.
Although some specific embodiments of the present invention have been demonstrated in detail with examples, it should be understood by a person skilled in the art that the above examples are only intended to be illustrative but not to limit the scope of the present invention.
This application is a National Stage of International Application No. PCT/CN2016/108513 filed on Dec. 5, 2016, which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2016/108513 | 12/5/2016 | WO | 00 |
