TRANSFER SYSTEM AND A FIXTURE THEREOF ADAPTABLE TO PERFORMING LEVELLING ALIGNMENT
A transfer system adaptable to performing levelling alignment includes a transfer head that picks up micro devices, the transfer head having a plurality of pick-up heads protruded from a bottom surface of the transfer head; and a levelling fixture configured to perform levelling alignment for the transfer head, the levelling fixture having a plurality of cavities that are concave downwards to correspondingly accommodate the pick-up heads respectively.
The present invention generally relates to transferring micro devices, and more particularly to a levelling fixture adaptable to performing levelling alignment.
2. Description of Related ArtA micro light-emitting diode (microLED, mLED or μ LED) display panel is one of flat display panels, and is composed of microscopic microLEDs each having a size of 1-100 micrometers. Compared to conventional liquid crystal display panels, the microLED display panels offer better contrast, response time and energy efficiency. Although both organic light-emitting diodes (OLEDs) and microLEDs possess good energy efficiency, the microLEDs, based on group III/V (e.g., GaN) LED technology, offer higher brightness, higher luminous efficacy and longer lifespan than the OLEDs.
During manufacturing a microLED display panel, a pick-up module is used to pick up individual microLEDs, and the microLEDs are then transferred to a display panel. Before picking up the microLEDs, the pick-up module need be pre-adjusted in a levelling alignment stage to make sure that the pick-up module is in a levelled position, such that the pick-up module can pick up microLEDs properly in the later transfer stages. Unfortunately, during the levelling alignment stage, the levelling normal (or perpendicular) force of the pick-up module exerted on a levelling fixture may usually cause damage to the pick-up heads of the pick-up module.
A need has thus arisen to propose a novel scheme to overcome the disadvantages of the conventional transfer system, particularly to prevent damage to the pick-up module while performing the levelling alignment stage.
SUMMARY OF THE INVENTIONIn view of the foregoing, it is an object of the embodiment of the present invention to provide a transfer system adaptable to effectively transferring micro devices without damaging to elements of the transfer system.
According to one embodiment, a transfer system adaptable to performing levelling alignment includes a transfer head and a levelling fixture. The transfer head picks up micro devices, the transfer head having a plurality of pick-up heads protruded from a bottom surface of the transfer head. The levelling fixture is configured to perform levelling alignment for the transfer head, the levelling fixture having a plurality of cavities that are concave downwards to correspondingly accommodate the pick-up heads respectively.
In the embodiment, the transfer system 100 may include a transfer head 11 configured to pick up the micro devices (not shown). The transfer head 11 may have a plurality of pick-up heads (commonly called stamps in the pertinent field) 111 protruded from a bottom surface of the transfer head 11. In the embodiment, as the transfer system 100 is specifically adaptable to mass transferring micro devices, the amount of the pick-up heads 111 may be at least hundreds or more. The transfer head 11 may include a device that adopts, for example, vacuum force, electromagnetic force, Van der Waals force or viscous force, to pick up the micro devices. In one embodiment, the transfer head 11, for example, has a size of 5×5 cm.
The transfer system 100 of the embodiment may include an adapter 12, disposed above the transfer head 11, configured to hold (a top surface of) the transfer head 11, for example, by vacuum force or by a clamp.
In the embodiment, the transfer system 100 may include a levelling fixture 13 configured, in companion with the adaptor 12, to perform levelling alignment for the transfer head 11. The levelling fixture 13 of the embodiment may preferably be made of a rigid material such as Sapphire or Granite. According to one aspect of the embodiment, the levelling fixture 13 may have a plurality of cavities 131 that are concave downwards. Particularly, the cavities 131 (of the levelling fixture 13) are arranged to correspondingly accommodate the pick-up heads 111 (of the transfer head 11) respectively. The cavities 131 of the levelling fixture 13 may be made, for example, by etching or laser drilling.
According to the transfer system 100 as disclosed above, due to the concave cavities 131 of the embodiment, the pick-up heads 111 of the transfer head 11 would not be damaged when the transfer head 11 are touching the levelling fixture 13 while performing a levelling alignment stage to properly fit the transfer head 11 to the levelling fixture 13, before mass transferring micro devices by the transfer head 11.
Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.
Claims
1. A transfer system adaptable to performing levelling alignment, the system comprising:
- a transfer head that picks up micro devices, the transfer head having a plurality of pick-up heads protruded from a bottom surface of the transfer head; and
- a levelling fixture configured to perform levelling alignment for the transfer head, the levelling fixture having a plurality of cavities that are concave downwards to correspondingly accommodate the pick-up heads respectively.
2. The system of claim 1, wherein the micro devices have a size less than 100 micrometers.
3. The system of claim 1, wherein the transfer head adopts vacuum force, electromagnetic force, Van der Waals force or viscous force to pick up the micro devices.
4. The system of claim 1, further comprising:
- an adapter disposed above the transfer head to hold the transfer head.
5. The system of claim 1, wherein the levelling fixture is made of a rigid material.
6. The system of claim 1, wherein the cavities of the levelling fixture are made by etching or laser drilling.
7. The system of claim 1, wherein a depth of the cavities is greater than a height of the pick-up heads.
8. The system of claim 1, wherein a pitch of the cavities is larger than a width of the cavities, which is greater than a width of the pick-up heads.
9. The system of claim 8, wherein a ratio of the width of the cavities to the width of the pick-up heads is greater than 1 and is less than or equal to 1.5.
10. The system of claim 8, wherein a ratio of the width of the cavities to the width of the pick-up heads is greater than 1.5.
11. The system of claim 1, wherein the plurality of cavities are interconnected to result in a single cavity to accommodate all the pick-up heads of the transfer head.
12. A fixture adaptable to performing levelling alignment, the fixture comprising:
- a levelling fixture configured to perform levelling alignment for a transfer head, the levelling fixture having a plurality of cavities that are concave downwards to correspondingly accommodate a plurality of pick-up heads of the transfer head respectively.
13. The fixture of claim 12, wherein the levelling fixture is made of a rigid material.
14. The fixture of claim 12, wherein the cavities of the levelling fixture are made by etching or laser drilling.
15. The fixture of claim 12, wherein a depth of the cavities is greater than a height of the pick-up heads.
16. The fixture of claim 12, wherein a pitch of the cavities is larger than a width of the cavities, which is greater than a width of the pick-up heads.
17. The fixture of claim 16, wherein a ratio of the width of the cavities to the width of the pick-up heads is greater than 1 and is less than or equal to 1.5.
18. The fixture of claim 16, wherein a ratio of the width of the cavities to the width of the pick-up heads is greater than 1.5.
19. The fixture of claim 12, wherein the plurality of cavities are interconnected to result in a single cavity to accommodate all the pick-up heads of the transfer head.
Type: Application
Filed: Apr 1, 2021
Publication Date: Oct 6, 2022
Inventors: Biing-Seng Wu (Tainan City), Chun-Jen Weng (Tainan City), Chao-Wen Wu (Tainan City)
Application Number: 17/220,638