CN112020781A

CN112020781A - Laser stripping method and laser stripping equipment for display panel

Info

Publication number: CN112020781A
Application number: CN201880091111.4A
Authority: CN
Inventors: 吕竟枫; 陈国峰; 林致远; 林俊仪
Original assignee: Shenzhen Royole Technologies Co Ltd
Current assignee: Shenzhen Royole Technologies Co Ltd
Priority date: 2018-04-20
Filing date: 2018-04-20
Publication date: 2020-12-01
Also published as: WO2019200611A1

Abstract

The invention provides a laser stripping method and laser stripping equipment for a display panel. The laser stripping method of the display panel comprises the following steps: providing a display device to be stripped, wherein the display device to be stripped comprises a carrier substrate and a display panel formed on the carrier substrate; scanning and irradiating the carrier substrate by using a first laser beam; scanning and irradiating the carrier substrate by using a second laser beam, wherein the first laser beam deflects towards a first direction relative to the normal of the incident surface of the carrier substrate, the second laser beam deflects towards a second direction relative to the normal of the incident surface of the carrier substrate, and the first direction is opposite to the second direction; and peeling the carrier substrate from the display panel. According to the laser stripping method of the display panel, the first laser beam and the second laser beam are deflected towards different directions to widen the effective irradiation area, so that the carrier substrate can be easily stripped from the display panel to avoid the damage of the display panel, and the display panel is protected.

Description

Laser stripping method and laser stripping equipment for display panel

Technical Field

The invention relates to the technical field of display, in particular to a display panel laser stripping method and laser stripping equipment.

Background

With the development of display technology, consumers have increasingly diversified and personalized demands for display modes, display effects and the like of display devices. Compared with the traditional display panel, the flexible display panel has the advantages of being foldable, curved, stretchable and the like, and is widely favored by consumers.

The existing display panel is separated from the carrier substrate through a Laser Lift Off (LLO) process. The absorption rate of laser is easily affected by the environment, which easily causes that the local display panel cannot be effectively separated during delamination, thereby damaging each film layer stacked in the display panel.

Disclosure of Invention

In view of the above problems in the prior art, the present invention provides a laser lift-off method and a laser lift-off apparatus for a display panel.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

in a first aspect, the present invention provides a laser lift-off method for a display panel, comprising the following steps:

providing a display device to be stripped, wherein the display device to be stripped comprises a carrier substrate and a display panel formed on the carrier substrate;

scanning and irradiating the carrier substrate by using a first laser beam;

scanning and irradiating the carrier substrate by using a second laser beam, wherein the first laser beam is deflected towards a first direction relative to a normal line of an incidence surface of the carrier substrate, the second laser beam is deflected towards a second direction relative to the normal line of the incidence surface of the carrier substrate, and the first direction is opposite to the second direction;

and peeling the carrier substrate from the display panel.

In a second aspect, the present invention provides a laser lift-off apparatus applying the display panel laser lift-off method, which includes an optical element for changing propagation paths of the first laser beam and the second laser beam.

According to the laser stripping method and the laser stripping equipment for the display panel, the first laser beam and the second laser beam are scanned and irradiated in different directions, so that the area shielded by a shielding object on the surface of the carrier substrate or a shielding object on the surface of the laser equipment can be reduced, and the scanning and irradiating range of the first laser beam and the second laser beam is widened. In addition, the first laser beam and the second laser beam are deflected towards different directions relative to the normal of the incident surface of the carrier substrate, so that the first laser beam and the second laser beam can effectively irradiate an interface where the carrier substrate is attached to the display panel, the carrier substrate can be easily peeled off from the display panel, the display panel is prevented from being damaged, and the display panel is protected.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic view of a manufacturing process of laser lift-off of a display panel according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a laser lift-off apparatus provided in an embodiment of the present invention.

Fig. 3 is a schematic view of a first light path structure of the display device to be peeled in fig. 1.

Fig. 4 is a schematic diagram of a second light path structure of the display device to be peeled off in fig. 1.

Fig. 5 is a flowchart of a laser lift-off method for a display panel according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and fig. 2, a schematic flow chart of laser lift-off manufacturing of a display panel is provided for an embodiment of the present invention. First, the display device 100 to be peeled is placed in the laser peeling apparatus 200. The display device 100 to be peeled includes a carrier substrate 1 and a display panel 2 formed on the carrier substrate 1. The display panel 2 has an interface 103 that is bonded to the carrier substrate 1.

The laser lift-off apparatus 200 includes a lift-off stage 3, a laser 4, an optical element 5, and a controller 6. The peeling table 3 is used for carrying the display device 100 to be peeled. The laser 4 is used to emit a laser beam. When the laser beam is irradiated to the interface 103 where the carrier substrate 1 and the display panel 2 are attached, the display panel 2 may be peeled off from the carrier substrate 1. The optical element 5 is used to change the path of the laser beam propagation. The optical element is, for example, a refractive element or a reflective element. Optionally, the optical element is a reflector. The controller 6 is used for controlling the laser 4 to emit the laser beam.

The laser beam may be a gas laser or a solid state laser. The solid-state laser is, for example, a semiconductor laser. The gas laser is, for example, but not limited to, an excimer laser, Nd-YAG laser, Ar laser, CO₂Laser, He — Ne laser, or the like. These laser beams can be roughly classified into Ultraviolet (UV) region laser beams (410nm or less), visible region-to-laser beams (500nm to 700nm), near-infrared region large laser beams (700nm to 2000nm), infrared region-to-laser beams (2000nm or more), and the like according to their wavelength. In this embodiment, the laser beam is a laser beam having a wavelength region of 410nm or less. Preferably, the laser beam has a wavelength of 308 nm.

The carrier substrate 1 is a glass substrate. Specifically, the glass substrate is, for example, but not limited to, soda lime glass, alkali-free glass, phosphoric acid-based glass, or quartz. The carrier substrate 1 has an entrance face 11 facing away from the display panel 2. It can be understood that environmental contaminants such as dust and impurities are easily accumulated on the carrier substrate 1 during production or transportation, so that a shielding object 12 is easily formed on the incident surface 11 of the carrier substrate 1, and the shielding object is easily remained on the lift-off laser apparatus, so that during laser lift-off, since the shielding object 12 blocks a path through which a laser beam passes, the laser beam cannot effectively irradiate the interface 103 where the carrier substrate 1 and the display panel 2 are attached, and thus cracks are easily caused in a region corresponding to the shielding object 12 during lift-off, thereby causing damage to internal circuits of the display panel 2 and risk of damage to a Thin Film Encapsulation (TFE).

In this embodiment, in the laser lift-off process of the display panel 2, the carrier substrate 1 is scanned and irradiated by the first laser beam L1, and then the carrier substrate 1 is scanned and irradiated by the second laser beam L2. The first laser beam L1 is deflected in a first direction X relative to a normal N1 of the incident surface 11 of the carrier substrate 1, and the second laser beam L2 is deflected in a second direction Y relative to a normal N1 of the incident surface 11 of the carrier substrate 1, wherein the first direction X is opposite to the second direction Y. Subsequently, the carrier substrate 1 is peeled off from the display panel 2.

It is understood that the normal N1 of the incident surface 11 of the carrier substrate 1 refers to a straight line perpendicular to the incident surface 11. In the present embodiment, the normal N1 refers to a perpendicular line along which the first laser beam L1 and the second laser beam L2 scan and irradiate the incident surface 11 of the carrier substrate 1. The first laser beam L1 and the second laser beam L2 are symmetrically distributed from a normal N1 of the incident surface 11 of the carrier substrate 1.

In other embodiments, one of the first laser beam L1 or the second laser beam L2 may be deflected toward the first direction X or the second direction Y relative to the normal N1 of the incident surface 11 of the carrier substrate 1, and the other of the first laser beam L1 or the second laser beam L2 may be parallel to the normal N1 of the incident surface 11 of the carrier substrate 1, that is, a first included angle α is formed between the first laser beam L1 and the second laser beam L2 (see fig. 4). The first included angle alpha is larger than 0 degree and smaller than 180 degrees.

In an embodiment, the first laser beam L1 and the second laser beam L2 scan and irradiate the carrier substrate 1 simultaneously. In another embodiment, after the first laser beam L1 scans and irradiates the carrier substrate 1, the second laser beam L2 scans and irradiates the carrier substrate 1 again.

The display device 100 includes opposing first and

second ends

101 and 102. In one embodiment, the first laser beam L1 is scanned from the first end 101 of the display device 100 to the second end 102 of the display device 100; the second laser beam L2 is scanned from the second end 102 of the display device 100 to the first end 101 of the display device 100. In another embodiment, the first laser beam L1 and the second laser beam L2 both scan from the first end 101 of the display device 100 to the second end 102 of the display device 100 or scan from the second end 102 of the display device 100 to the first end 101 of the display device 100.

As shown in fig. 3, the first laser beam L1 and the second laser beam L2 both scan and irradiate to the incident surface 11 of the carrier substrate 1 vertically, that is, the first laser beam L1 is parallel to the second laser beam L2, and neither the first laser beam L1 nor the second laser beam L2 is deflected with respect to the normal N1 of the incident surface 11 of the carrier substrate 1. When the first laser beam L1 is parallel to the second laser beam L2, the length of the barrier 12 on the carrier substrate 1 blocking the first laser beam L1 and the second laser beam L2 from irradiating the carrier substrate 1 and the display panel 2 is D1. As shown in fig. 4, the first laser beam L1 and the second laser beam L2 both scan obliquely to the incident surface 11 of the carrier substrate 1, i.e., both the first laser beam L1 and the second laser beam L2 are deflected from the normal N1 of the incident surface 11 of the carrier substrate 1. At this time, the first included angle α is formed between the first laser beam L1 and the second laser beam L2. When the first included angle α is formed between the first laser beam L1 and the second laser beam L2, the length of the barrier 12 on the carrier substrate 1 blocking the first laser beam L1 and the second laser beam L2 from irradiating the carrier substrate 1 and the display panel 2 is D2. Wherein D2 is less than D1. Therefore, when a first included angle α is formed between the first laser beam L1 and the second laser beam L2, the area of the first laser beam L1 and the second laser beam L2 shielded by the shielding object 12 on the surface of the carrier substrate 1 or the shielding object 12 on the surface of the laser device is reduced, and the scanning irradiation range of the first laser beam L1 and the second laser beam L2 is widened, so that the carrier substrate 1 can be peeled off from the display panel 2 to prevent the display panel 2 from being damaged, and the display panel 2 is protected.

The display panel 2 includes a substrate 10, a buffer layer 20, and a functional layer 30, which are sequentially stacked. The buffer layer 20 is disposed above the substrate 10. A carrier substrate 1 is disposed below the substrate 10.

It will be appreciated that the display panel 2 may be a flexible display panel or a non-flexible display panel. Preferably, the Display panel 2 is a flexible Display panel, and the flexible Display panel is, for example, but not limited to, a product or a component having a specific function, such as a Liquid Crystal Display (LCD) panel, a Quantum Dot Light Emitting Diodes (QLED) panel, an electronic paper (E-paper Display, EPD), a Touch screen (Touch panel), a flexible solar cell (PV) panel, a Radio Frequency tag (Radio Frequency Identification, RFID), and the like.

The substrate 10 is a flexible substrate, that is, a flexible substrate, and is configured to support the entire display panel 2. In this embodiment, the substrate 10 is a Polyimide (PI) substrate. It is understood that, in other embodiments, the substrate 10 may also be one of a Polyamide (PA) substrate, a Polycarbonate (PC) substrate, a Polyethersulfone (PES) substrate, a polyethylene terephthalate (PET) substrate, a polyethylene naphthalate (PEN) substrate, a polymethyl methacrylate (PMMA) substrate, and a Cyclic Olefin Copolymer (COC) substrate. The substrate 10 may be used for bending in which the curvature changes during use, may be a fixed curved surface in which the curvature does not change, or may be a flat surface in a form in which it is mounted on an electronic device.

The buffer layer 20 is disposed above the substrate 10. The buffer layer 20 is made of an inorganic insulating material. The inorganic insulating material is, for example, but not limited to, silicon nitride (SiNx) or silicon oxide (SiOx). It is understood that in other embodiments, the buffer layer 20 may also be a water oxygen barrier.

It is understood that the functional layer 30 is various functional material layers constituting products or parts having a display function such as a liquid crystal display, a quantum dot display, a mobile phone, a tablet computer, a navigator, etc. The functional layer 30 may be, but is not limited to, one of an electrode layer, a wiring layer, a light emitting layer, a gas barrier layer, an adhesive layer, a thin film transistor, a transparent conductive layer, or the like, or a combination thereof. In the present embodiment, the functional layer 30 is a wiring layer. The wiring layer is specifically a metal wire.

Referring to fig. 5, a flowchart of a laser lift-off method for a display panel is provided according to an embodiment of the present invention. The laser lift-off method of the display panel 2 comprises the following steps:

step 501, providing a display device 100 to be peeled, where the display device 100 to be peeled includes a carrier substrate 1 and a display panel 2 formed on the carrier substrate 1.

In step 503, the carrier substrate 1 is scanned and irradiated with the first laser beam L1.

Step 505, scanning and irradiating the carrier substrate 1 with a second laser beam L2, wherein the first laser beam L1 is deflected towards a first direction X relative to a normal N1 of the incident surface 11 of the carrier substrate 1, and the second laser beam L2 is deflected towards a second direction Y relative to a normal N1 of the incident surface 11 of the carrier substrate 1, and the first direction X is opposite to the second direction Y.

Step 507, peeling the carrier substrate 1 and the display panel 2.

As shown in fig. 1 to 4, in an embodiment, the first laser beam L1 and the second laser beam L2 are symmetrically distributed from a normal N1 of the incident surface 11 of the carrier substrate 1. A first included angle alpha is formed between the first laser beam L1 and the second laser beam L2, and the first included angle alpha is larger than 0 degree and smaller than 180 degrees. The first laser beam L1 is scan-irradiated from the first end 101 toward the second end 102 of the display device 100, and the second laser beam L2 is scan-irradiated from the second end 102 toward the first end 101 of the display device 100. It is understood that, in another embodiment, the first laser beam L1 may scan from the second end 102 of the display device 100 toward the first end 101, and the second laser beam L2 may scan from the first end 101 of the display device 100 toward the second end 102.

In another embodiment, the first laser beam L1 and the second laser beam L2 both scan-illuminate from the first end 101 towards the second end 102 of the display device 100 or scan-illuminate from the second end 102 towards the first end 101 of the display device 100.

In the present embodiment, the first laser beam L1 and the second laser beam L2 are both irradiated from a side of the carrier substrate 1 away from the display panel 2. It is understood that, in other embodiments, the first laser beam L1 and the second laser beam L2 may also be irradiated from a side of the carrier substrate 1 close to the display panel 2. At least one of the first laser beam L1 and the second laser beam L2 is obliquely irradiated to the carrier substrate 1. Alternatively, both the first laser beam L1 and the second laser beam L2 are obliquely irradiated to the carrier substrate 1.

Referring to fig. 4 again, a second included angle β departing from the normal N1 is formed between the first laser beam L1 and the plane of the carrier substrate 1 where the incident surface 11 departing from the display panel 2 is located, a third included angle departing from the normal N1 is formed between the second laser beam L2 and the plane of the carrier substrate 1 where the incident surface 11 departing from the display panel 2 is located, and both the second included angle β and the third included angle are acute angles.

Optionally, the second included angle β and the third included angle are both 0 to 85 degrees. Preferably, in order to more effectively irradiate the first laser beam L1 and the second laser beam L2 onto the interface 103 where the carrier substrate 1 and the substrate 10 are attached, both the second included angle β and the third included angle are 0 to 50 degrees.

In this embodiment, the second included angle β is equal to the third included angle. It is understood that in other embodiments, the second included angle β is not equal to the third included angle. Specifically, when the obstruction 12 is an axisymmetric figure, the second included angle β is equal to the third included angle. When the obstruction 12 is a non-axisymmetric pattern, that is, the obstruction 12 is an irregular pattern, the second included angle β may not be equal to the third included angle. Therefore, the area of the first laser beam L1 and the second laser beam L2 shielded by the shield 12 on the surface of the carrier substrate 1 or the shield 12 on the surface of the laser device is reduced, so as to widen the scanning irradiation range of the first laser beam L1 and the second laser beam L2, thereby facilitating the carrier substrate 1 to be peeled off from the display panel 2 to avoid the damage of the display panel 2, and further protecting the display panel 2.

Optionally, on the basis of the foregoing embodiment, an improvement is made on a laser lift-off method for a display panel 2, and specifically, before scanning and irradiating the carrier substrate 1 and the display panel 2 with the first laser beam L1, the method further includes:

detecting the size of a mask 12 on an incident surface 11 of the carrier substrate 1;

determining the degree of deflection of the first laser beam L1 and the second laser beam L2, i.e. the angle between the second angle β and the third angle, according to the size of the mask 12 and the size of the surface mask.

It is understood that the degree of deflection refers to an angle between the first laser beam L1 or the second laser beam L2 and a normal N1 of the incident surface 11 of the carrier substrate 1. The size of the obstruction 12 is inversely proportional to the angle of the second included angle β and the third included angle. Specifically, when the size of shelter 12 is great, second contained angle beta with the angle of third contained angle is less, works as when the size of shelter 12 is less, second contained angle beta with the angle of third contained angle is bigger, thereby can widen first laser beam L1 with second laser beam L2 scans and shines carrier substrate 1 with display panel 2's scope, so as to do benefit to carrier substrate 1 follows peel off and avoid on display panel 2 causes the damage, and then has protected display panel 2.

In an embodiment, the first laser beam L1 and the second laser beam L2 scan and irradiate the carrier substrate 1 and the display panel 2 simultaneously, so that the time for peeling the display panel 2 from the carrier substrate 1 can be shortened, and the peeling efficiency can be improved. In another embodiment, after the first laser beam L1 scans and irradiates the carrier substrate 1 and the display panel 2, the second laser beam L2 re-scans and irradiates the carrier substrate 1 and the display panel 2, i.e. the first laser beam L1 and the second laser beam L2 scan and irradiate the carrier substrate 1 and the display panel 2 back and forth, the laser lift-off device 200 can thus be provided with one of the lasers 4, simplifying the structure of the laser lift-off device 200, and ensures that the scanning irradiation parameters of the first laser beam L1 and the second laser beam L2 are consistent, thereby ensuring the energy stability of the first laser beam L1 and the second laser beam L2, thereby improving the effective scanning irradiation of the first laser beam L1 and the second laser beam L2 to facilitate the peeling of the carrier substrate 1 from the display panel 2. Further, in other embodiments, the first laser beam L1 and the second laser beam L2 may scan and irradiate the carrier substrate 1 and the display panel 2 at preset time intervals.

Wherein, in the present embodiment, the laser types of the first laser beam L1 and the second laser beam L2 include gas laser or solid laser. The carrier substrate 1 is a glass substrate. The display panel 2 includes a substrate 10, a buffer layer 20, and a functional layer 30 sequentially formed on the carrier substrate 1. The substrate 10 is a polyimide layer, and the functional layer 30 is a wiring layer.

According to the laser stripping method of the display panel, the first laser beam and the second laser beam are scanned and irradiated in different directions, so that the area shielded by a shielding object on the surface of the carrier substrate or a shielding object on the surface of laser equipment can be reduced, and the scanning and irradiation range of the first laser beam and the second laser beam is widened. In addition, the first laser beam and the second laser beam are deflected towards different directions relative to the normal of the incident surface of the carrier substrate, so that the first laser beam and the second laser beam can effectively irradiate an interface where the carrier substrate is attached to the display panel, the carrier substrate can be easily peeled off from the display panel, the display panel is prevented from being damaged, and the display panel is protected.

The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.

Claims

A laser lift-off method for a display panel comprises the following steps:

providing a display device to be stripped, wherein the display device to be stripped comprises a carrier substrate and a display panel formed on the carrier substrate;

scanning and irradiating the carrier substrate by using a first laser beam;

scanning and irradiating the carrier substrate by using a second laser beam, wherein the first laser beam is deflected towards a first direction relative to a normal line of an incidence surface of the carrier substrate, the second laser beam is deflected towards a second direction relative to the normal line of the incidence surface of the carrier substrate, and the first direction is opposite to the second direction;

and peeling the carrier substrate from the display panel.
The laser lift off method of claim 1, wherein the first laser beam and the second laser beam are symmetrically distributed from a normal to an incident surface of the carrier substrate.
The laser lift off method of claim 1 wherein the first laser beam and the second laser beam are both irradiated from a side of the carrier substrate facing away from the display panel.
The laser lift off method of claim 1 wherein a first angle is formed between the first laser beam and the second laser beam, the first angle being greater than 0 degrees and less than 180 degrees.
The laser lift off method of claim 4 wherein the first laser beam and the plane of the incident surface of the carrier substrate facing away from the display panel form a second angle that faces away from the normal, the second laser beam and the plane of the incident surface of the carrier substrate facing away from the display panel form a third angle that faces away from the normal, and both the second angle and the third angle are acute angles.
The laser lift off method of claim 5, wherein the acute angle is 0-85 degrees.
The laser lift off method of claim 6, wherein the acute angle is 0-50 degrees.
The laser lift off method of claim 5, wherein the second angle is equal to the third angle.
The display panel laser lift off method of claim 1, further comprising, prior to said scanning irradiating said carrier substrate with said first laser beam:

detecting the size of a shelter of the incident surface of the carrier substrate;

and determining the deflection degree of the first laser beam and the second laser beam according to the size of the surface obstruction.
The laser lift off method of display panel of claim 1 wherein said first laser beam and said second laser beam scan illuminate said carrier substrate simultaneously.
The laser lift off method of display panel of claim 1 wherein said first laser beam and said second laser beam scan illuminate said carrier substrate at predetermined time intervals.
The laser lift off method of claim 11 wherein said second laser beam is rescanned to illuminate said carrier substrate after said first laser beam is rescanned to illuminate said carrier substrate.
The laser lift off method of display panel of claim 12 wherein said display device has opposite first and second ends, said first laser beam being scanned from said first end of said display device to said second end of said display device; the second laser beam is scanned and irradiated from the second end of the display device to the first end of the display device.
The laser lift off method of claim 13, wherein the first laser beam and the second laser beam are scanned from a first end of the display device to a second end of the display device or scanned from the second end of the display device to the first end of the display device.
The laser lift off method of display panel of claim 1, wherein the carrier substrate is a glass substrate.
The display panel laser lift off method of claim 1, wherein the type of the first laser beam and the second laser beam comprises a gas laser or a solid state laser.
The laser lift off method of display panel of claim 1 wherein the first laser beam and the second laser beam are both 308nm in wavelength.
The laser lift-off method for a display panel according to claim 1, wherein the display panel comprises a substrate, a buffer layer and a functional layer sequentially formed on the carrier substrate.
The laser lift off method for a display panel according to claim 18, wherein the substrate is a polyimide layer and the functional layer is a wiring layer.
A laser lift-off apparatus to which the laser lift-off method of a display panel according to any one of claims 1 to 19 is applied, comprising an optical element for changing a propagation path of the first laser beam and the second laser beam.