A bright spot defect correction system for OLED display panel

Abstract

The present invention discloses a bright spot defect correction system for an OLED display panel, comprising a beam shaping unit, a beam relay scanning unit, a beam projection unit, an illumination unit and an imaging unit; the beam shaping unit is used to shape an incident Gaussian beam into a Gauss-Bessel beam and output it; the beam relay scanning unit is arranged on the output optical path of the beam shaping unit; the beam projection unit is arranged on the output optical path of the beam relay scanning unit; the OLED display panel to be repaired is placed at the beam focusing position after the beam projection unit, and the beam focusing point after the beam projection unit is aligned with the bright spot defect area of ​​the OLED display panel to be repaired; the illumination unit is arranged on the optical path in the beam projection unit; and the imaging unit is arranged on the retroreflection optical path of the illumination unit. The operation is more convenient and the repair efficiency is higher.

Description

Technical Field

[0001] The invention belongs to the field of laser equipment, and in particular relates to an OLED display panel bright spot defect correction system. Background Art

[0002] In the field of semiconductor display, automatic repair equipment for semiconductor display panels based on laser technology is also becoming one of the indispensable important equipment. Its main needs include process improvement of existing production lines, "better" repair of defective display products, and supporting construction of new high-generation production lines. In the field of OLED semiconductor display panel manufacturing, the existing technology uses Gaussian laser beam direct focusing to repair bright spot defects of OLED display panels. Since the laser focal depth of Gaussian beam under the repair parameters is generally less than 10μm, it has high requirements for the accuracy and real-time performance of laser focusing, and must be used in conjunction with the autofocus system, resulting in strict requirements on the focusing of the beam, poor adaptability of the entire repair system, and poor repair effect. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a laser repair system with a simple structure, strong adaptability, good repair effect, and a focal depth that can be extended to the order of hundreds of microns to millimeters. The system can greatly reduce the requirements for focusing the light beam on the surface of the OLED display panel to be repaired, and also relax the requirements for the flatness of the sample processing surface, and can accurately and stably repair the bright spot defects on the OLED display panel.

[0004] In order to achieve the above-mentioned object, the technical solution of the present invention is as follows: an OLED display panel bright spot defect correction system comprises a beam shaping unit, a beam relay scanning unit, a beam projection unit, an illumination unit and an imaging unit;

[0005] The beam shaping unit is used to shape the incident Gaussian beam into a Gaussian-Bessel beam and output it, and the output optical path thereof has a first Bessel zone;

[0006] The beam relay scanning unit is arranged on the output optical path of the beam shaping unit, and is used to relay the Gauss-Bessel beam output by the beam shaping unit to the far field, and make the Gauss-Bessel beam deviate from the optical axis and perform beam scanning;

[0007] The beam projection unit is arranged on the output optical path of the beam relay scanning unit, and is used to flexibly shrink and focus the Gauss-Bessel beam to adapt to the required processing parameters;

[0008] The OLED display panel to be repaired is placed at the beam focusing position behind the beam projection part, and the beam focusing point behind the beam projection part is aligned with the bright spot defect area of ​​the OLED display panel to be repaired;

[0009] The illumination unit is arranged on the optical path in the light beam projection unit, and is used to perform coaxial or off-axis illumination on the surface of the OLED display panel to be repaired;

[0010] The imaging unit is arranged on the retroreflective light path of the illumination unit, and is used for performing bright field or dark field microscopic observation on the surface of the OLED display panel to be repaired.

[0011] The beneficial effect of the above technical solution is that, among others, the incident Gaussian beam is shaped into a Gaussian-Bessel beam by the beam shaping unit, so that the focal depth can be extended to a very long range of hundreds of microns to millimeters, which greatly reduces the stringent requirements for focusing and aligning the beam on the sample surface during laser repair, thus making the entire system more adaptable, more convenient to operate, and more efficient in repair.

[0012] In the above technical solution, the beam shaping part is a spatial light modulator of the conical mirror phase or a positive conical prism or a negative conical prism with a base angle range of 0.5-5°; the incident Gaussian beam is a laser beam with a pulse width of 10-100ns and a repetition frequency of 20-60kHz; 1 / e of the incident beam 2 The diameter is 5-10mm.

[0013] The beneficial effect of the above technical solution is that it can shape the incident Gaussian beam into a Gaussian-Bessel beam.

[0014] The beam relay scanning unit in the above technical solution includes a first lens, a beam scanner and a second lens which are sequentially arranged on the output light path of the beam shaping unit. The beam scanner is used to turn the output light path by 90° and scan the shaped light beam. The front focal plane of the first lens is arranged in the first Bessel zone, and the optical axes of the first lens and the second lens coincide with the optical axis of the incident Gaussian light beam. The first lens and the second lens are confocally distributed, and the confocal position of the two is the spatial spectrum position of the first Bessel zone, and the position of the back focal plane of the second lens is the second Bessel zone.

[0015] The beneficial effect of the above technical solution is that the near-field Gauss-Bessel beam is relayed to the far field through the first lens and the second lens, making the deployment of the beam scanner easier.

[0016] In the above technical solution, the first lens and the second lens are plano-convex positive lenses or bi-convex positive lenses with equal focal lengths.

[0017] The beneficial effect of the above technical solution is that it has a simple structure.

[0018] In the above technical solution, the scanning head of the beam scanner is a fast reflection mirror or a scanning galvanometer, and its rotation center coincides with the turning point of the optical axis of the incident Gaussian beam and the spatial spectrum position of the first Bessel zone.

[0019] The beneficial effect of the above technical solution is that it has a simple structure.

[0020] The beam projection unit in the above technical solution includes a third lens and a fourth lens which are sequentially arranged on the output light path of the beam relay scanning unit. The third lens and the fourth lens are both concentrically distributed with the second lens. The front focal plane of the third lens is located in the second Bessel zone. The third lens and the fourth lens are confocally arranged, and their confocal positions are set to the spatial spectrum position of the second Bessel zone. The focal length of the fourth lens is smaller than that of the third lens. The back focal plane of the fourth lens is set to the third Bessel zone. The OLED display panel to be repaired is placed in the third Bessel zone.

[0021] The beneficial effect of the above technical solution is that the light beam output by the fourth lens is focused on the surface of the OLED display panel to be repaired to repair the bright spots thereon.

[0022] In the above technical solution, the third lens is a plano-convex positive lens or a bi-convex positive lens; the fourth lens is a plano-convex positive lens, a bi-convex positive lens or a laser processing objective lens.

[0023] The beneficial effect of the above technical solution is that it has a simple structure.

[0024] The illumination unit in the above technical solution includes an illumination light source, a first beam splitter prism and a second beam splitter prism; the first beam splitter prism has a transmission-reflection ratio of 1:1, and is arranged in the output light path of the illumination light source; the second beam splitter prism has a transmission-reflection ratio of 1:1, and is arranged in the reflection light path of the first beam splitter prism, and is located at the confocal position of the third lens and the fourth lens, and the imaging unit is arranged on the reverse extension line of the reflection light path of the first beam splitter prism.

[0025] The beneficial effect of the above technical solution is that it is convenient to observe the surface of the OLED display panel to be repaired in real time.

[0026] The illumination light source in the above technical solution is a coaxial light source or an off-axis light source.

[0027] The beneficial effects of the above technical solution are: off-axis lighting can improve detail resolution, while on-axis lighting can provide clear imaging levels and uniform brightness, both of which can improve the recognition of the surface of the OLED display to be repaired.

[0028] The imaging unit in the above technical solution includes an imaging tube lens and an imaging sensor which are sequentially arranged on the reverse extension line of the reflecting light path of the first beam splitting prism.

[0029] The beneficial effect of the above technical solution is that the bright spot defect on the OLED display panel to be repaired can be clearly magnified by the imaging unit and displayed through the display device for real-time observation and aiming. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a module diagram of the OLED display panel bright spot defect correction system according to an embodiment of the present invention;

[0031] Figure 2 A light path diagram of a light beam of the OLED display panel bright spot defect correction system according to an embodiment of the present invention without deflection;

[0032] Figure 3 A light path diagram of a light beam deflected by a system for correcting bright spot defects of an OLED display panel according to an embodiment of the present invention;

[0033] Figure 4 A schematic diagram showing the comparison of the effects of a Gaussian-Bessel beam and a normal Gaussian beam focused on an OLED display panel;

[0034] Figure 5 It is a schematic diagram of the OLED display panel bright spot defect correction system according to an embodiment of the present invention scanning and repairing bright spot defects on the OLED display panel to be repaired.

[0035] In the figure: 1 beam shaping unit, 2 beam relay scanning unit, 21 first lens, 22 beam scanning element, 23 second lens, 3 beam projection unit, 31 third lens, 32 fourth lens, 4 lighting unit, 41 lighting light source, 42 first beam splitting prism, 43 second beam splitting prism, 5 imaging unit, 51 imaging tube lens, 52 imaging sensor, 6 OLED display panel to be repaired. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] like Figure 1 and Figure 5 As shown, this embodiment provides an OLED display panel bright spot defect correction system, including a beam shaping unit 1, a beam relay scanning unit 2, a beam projection unit 3, an illumination unit 4 and an imaging unit 5;

[0038] The beam shaping unit 1 is used to shape the incident Gaussian beam into a Gaussian-Bessel beam and output it, and the output optical path thereof has a first Bessel zone;

[0039] The beam relay scanning unit 2 is arranged on the output optical path of the beam shaping unit 1, and is used to relay the Gauss-Bessel beam output by the beam shaping unit 1 to the far field, and make the Gauss-Bessel beam deviate from the optical axis and perform beam scanning;

[0040] The beam projection unit 3 is arranged on the output optical path of the beam relay scanning unit 2, and is used to flexibly shrink and focus the Gauss-Bessel beam to adapt to the required processing parameters;

[0041] The OLED display panel 6 to be repaired is placed at the beam focusing position after the beam projection unit 3, and the beam focusing point after the beam projection unit 3 is aligned with the bright spot defect area of ​​the OLED display panel 6 to be repaired;

[0042] The lighting unit 4 is arranged on the optical path in the light beam projection unit 3, and is used to perform coaxial or off-axis illumination on the surface of the OLED display panel 6 to be repaired;

[0043] The imaging unit 5 is arranged on the retroreflective light path of the illumination unit 4, and is used for bright field or dark field microscopic observation of the surface of the OLED display panel 6 to be repaired, wherein the incident Gaussian light beam is shaped into a Gaussian-Bessel light beam by the beam shaping unit, so that the focal depth can be extended to a very long range of hundreds of microns to millimeters, which greatly reduces the stringent requirements for focusing and aligning the light beam on the sample surface during laser repair, thereby making the entire system more adaptable, more convenient to operate, and more efficient in repair.

[0044] The beam shaping unit 1 in the above technical solution is a spatial light modulator of the conical mirror phase or a positive conical prism or a negative conical prism with a base angle range of 0.5-5°; the incident Gaussian beam is a laser beam with a pulse width of 10-100ns and a repetition frequency of 20-60kHz; 1 / e of the incident beam 2 The diameter is 5-10 mm, so that the incident Gaussian beam can be shaped into a Gaussian-Bessel beam.

[0045] like Figure 2 and Figure 3As shown, the beam relay scanning unit 2 in the above technical solution includes a first lens 21, a beam scanner 22 and a second lens 23 which are sequentially arranged on the output light path of the beam shaping unit 1. The beam scanner 22 is used to turn the output light path by 90° and scan the shaped light beam. The front focal plane of the first lens 21 is arranged in the first Bessel zone, and the optical axes of the first lens 21 and the second lens 23 coincide with the optical axis of the incident Gaussian light beam. The first lens 21 and the second lens 23 are confocally distributed, and the confocal position of the two is the spatial spectrum position of the first Bessel zone, and the position of the back focal plane of the second lens 23 is the second Bessel zone. In this way, the near-field Gauss-Bessel beam is relayed to the far field through the first lens and the second lens, making the deployment of the beam scanner easier.

[0046] In the above technical solution, the first lens 21 and the second lens 23 are plano-convex positive lenses or bi-convex positive lenses with equal focal lengths.

[0047] In the above technical solution, the scanning head of the beam scanner 22 is a fast reflection mirror or a scanning galvanometer, and its rotation center coincides with the turning point of the optical axis of the incident Gaussian beam and the spatial spectrum position of the first Bessel zone.

[0048] The beam projection unit 3 in the above technical solution includes a third lens 31 and a fourth lens 32 which are sequentially arranged on the output light path of the beam relay scanning unit 2. The third lens 31 and the fourth lens 32 are both concentrically distributed with the second lens 23. The front focal plane of the third lens 31 is located in the second Bessel zone. The third lens 31 and the fourth lens 32 are confocally arranged, and their confocal positions are the spatial spectrum positions of the second Bessel zone. The focal length of the fourth lens 32 is smaller than that of the third lens 31, and the back focal plane of the fourth lens 32 is the third Bessel zone. The OLED display panel 6 to be repaired is placed in the third Bessel zone, so that the light beam output from the fourth lens is focused on the surface of the OLED display panel to be repaired to repair the bright spots on it.

[0049] In the above technical solution, the third lens 31 is a plano-convex positive lens or a bi-convex positive lens; the fourth lens 32 is a plano-convex positive lens, a bi-convex positive lens or a laser processing objective lens.

[0050] The lighting unit 4 in the above technical solution includes an illumination light source 41, a first beam splitting prism 42 and a second beam splitting prism 43; the first beam splitting prism 42 has a transmission-reflection ratio of 1:1, and is arranged in the output light path of the illumination light source 41; the second beam splitting prism 43 has a transmission-reflection ratio of 1:1, and is arranged in the reflection light path of the first beam splitting prism 42, and is located at the confocal position of the third lens 31 and the fourth lens 32, and the imaging unit 5 is arranged on the reverse extension line of the reflection light path of the first beam splitting prism 42, so as to facilitate timely observation of the surface of the OLED display panel to be repaired.

[0051] The illumination light source 41 described in the above technical solution is a coaxial light source or an off-axis light source. Off-axis illumination can improve the focusing depth, while coaxial illumination can produce clear imaging and uniform brightness, both of which can further improve the recognition of the surface of the OLED display screen to be repaired.

[0052] The imaging unit 5 in the above technical solution includes an imaging tube lens 51 and an imaging sensor 52 which are sequentially arranged on the reverse extension line of the reflected light path of the first beam splitting prism 42. In this way, the bright spot defects on the OLED display panel to be repaired can be clearly magnified with the help of the imaging unit and displayed through a display device for real-time observation and aiming.

[0053] Wherein, the incident Gaussian beam is TEM 00 The fundamental mode Gaussian beam can be spatially filtered in advance by introducing a small aperture in the Fourier spectrum plane to obtain a high-quality fundamental mode Gaussian beam.

[0054] Preferably, the key parameters of the beam projection unit are related to each other as follows:

[0055] θ1=arcsin(n axi sinα)–α (1)

[0056] θ2=arctan(f3 tanθ1 / f4); (2)

[0057] w4=f3 w3 / f4 (3)

[0058] d≈2.405 / (k sinθ) (4)

[0059] DOF≈w / tanθ (5)

[0060] Where: -θ1 is the semi-cone angle of the Bessel beam before the projection part;

[0061] -n axi is the material refractive index of the conical prism;

[0062] -α is the base angle of the conical prism;

[0063] -θ2 is the half cone angle of the Bessel beam after the beam projection part;

[0064] -f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and the ratio of the projection beam reduction system is f3 / f4;

[0065] -w3 is the ring width of the incident beam, and w4 is the ring width of the beam after passing through the projection beam reduction system;

[0066] -d is the center spot radius of the Bessel beam (the first zero point position);

[0067] -k is the vacuum wave vector of the light beam;

[0068] -DOF is the depth of focus of the light beam.

[0069] Among them, further preferably, the OLED display panel bright spot defect correction system described in this embodiment may also include a high-precision two-dimensional mobile platform, and the OLED display panel to be repaired is placed on the two-dimensional mobile platform, and is driven by the two-dimensional mobile platform to perform two-dimensional movement so as to locate the bright spot defect and implement scanning repair.

[0070] The OLED display panel bright spot defect correction system described in this embodiment can accurately and stably repair common bright spot defects caused by thin film transistor (TFT) unit failure, aging process failure, etc. in the manufacturing of the OLED display panel to be repaired.

[0071] Compared with the prior art, the present invention is characterized in that it shapes the ordinary Gaussian beam into a Gaussian-Bessel beam through the beam shaping unit (the focusing diagram of the two can be referred to in Figure 4 ), taking advantage of the fact that the focal depth of Gauss-Sebel can be extended to hundreds of microns to millimeters, the requirements for its focusing accuracy are reduced, making its operation more convenient and the repair efficiency higher.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for correcting bright spot defects of an OLED display panel, characterized in that: It comprises a beam shaping unit (1), a beam relay scanning unit (2), a beam projection unit (3), an illumination unit (4) and an imaging unit (5); The beam shaping unit (1) is used to shape the incident Gaussian beam into a Gaussian-Bessel beam and output it, and the output optical path thereof has a first Bessel zone; The beam relay scanning unit (2) is arranged on the output optical path of the beam shaping unit (1), and is used to relay the Gauss-Bessel beam output by the beam shaping unit (1) to the far field, and to make the Gauss-Bessel beam deviate from the optical axis and perform beam scanning; The light beam projection unit (3) is arranged on the output light path of the light beam relay scanning unit (2), and is used to flexibly shrink and focus the Gauss-Bessel light beam to adapt to the required processing parameters; The light beam relay scanning unit (2) comprises a second lens (23) arranged on the output light path of the light beam shaping unit (1); The light beam projection unit (3) comprises a third lens (31) and a fourth lens (32) which are sequentially arranged on the output light path of the light beam relay scanning unit (2); the third lens (31) and the fourth lens (32) are both concentrically distributed with the second lens (23); the front focal plane of the third lens (31) is located in the second Bessel zone; the third lens (31) and the fourth lens (32) are cofocally arranged, and their cofocal positions are set to the spatial spectrum position of the second Bessel zone; the focal length of the fourth lens (32) is smaller than that of the third lens (31); the back focal plane of the fourth lens (32) is set to the third Bessel zone; and the OLED display panel (6) to be repaired is placed in the third Bessel zone; The key parameters of the beam projection unit are related to each other as follows: θ1=arcsin(n axi sinα)–α (1) θ2=arctan(f3 tanθ1 / f4); (2) w4=f3 w3 / f4 (3) d≈2.405 / (k sinθ)(4) DOF ≈ w / tanθ(5) Where: θ1 is the semi-cone angle of the Bessel beam before the projection part; n axi is the material refractive index of the conical prism; α is the base angle of the conical prism; θ2 is the semi-cone angle of the Bessel beam after the beam projection part; f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and the ratio of the projection beam reduction system is f3 / f4; w3 is the ring width of the incident beam, and w4 is the ring width of the beam after passing through the projection beam reduction system; d is the central spot radius of the Bessel beam; k is the vacuum wave vector of the beam; DOF is the focal depth of the beam; The OLED display panel (6) to be repaired is placed at a light beam focusing position behind the light beam projection unit (3), and the light beam focusing point behind the light beam projection unit (3) is aligned with a bright spot defect area of ​​the OLED display panel (6) to be repaired; The illumination unit (4) is arranged on the optical path in the light beam projection unit (3), and is used to perform coaxial or off-axis illumination on the surface of the OLED display panel (6) to be repaired; The imaging unit (5) is arranged on the retroreflective light path of the illumination unit (4) and is used to perform bright field or dark field microscopic observation on the surface of the OLED display panel (6) to be repaired.

2. The OLED display panel bright spot defect correction system according to claim 1, characterized in that: The beam shaping part (1) is a spatial light modulator of the conic phase or a positive conical prism or a negative conical prism with a base angle range of 0.5-5°; the incident Gaussian beam is a laser beam with a pulse width of 10-100ns and a repetition frequency of 20-60kHz; 1 / e of the incident beam 2 The diameter is 5-10mm.

3. The OLED display panel bright spot defect correction system according to claim 1 or 2, characterized in that: The beam relay scanning unit (2) further comprises a first lens (21) and a beam scanning element (22) arranged on the output light path of the beam shaping unit (1), and the first lens (21), the beam scanning element (22) and the second lens (23) are arranged in sequence on the output light path of the beam shaping unit (1), the beam scanning element (22) is used to turn the output light path by 90 degrees and scan the shaped light beam, the front focal plane of the first lens (21) is arranged in the first Bessel zone, and the optical axes of the first lens (21) and the second lens (23) are coincident with the optical axis of the incident Gaussian light beam, the first lens (21) and the second lens (23) are cofocally distributed, and the cofocal position of the two is the spatial spectrum position of the first Bessel zone, and the position of the back focal plane of the second lens (23) is set as the second Bessel zone.

4. The OLED display panel bright spot defect correction system according to claim 3, characterized in that: The first lens (21) and the second lens (23) are plano-convex positive lenses or bi-convex positive lenses with equal focal lengths.

5. The OLED display panel bright spot defect correction system according to claim 3, characterized in that: The scanning head of the beam scanning element (22) is a fast reflection mirror or a scanning galvanometer, and its rotation center coincides with the turning point of the optical axis of the incident Gaussian beam and the spatial spectrum position of the first Bessel zone.

6. The OLED display panel bright spot defect correction system according to claim 1, characterized in that: The third lens (31) is a plano-convex positive lens or a bi-convex positive lens; the fourth lens (32) is a plano-convex positive lens or a bi-convex positive lens.

7. The OLED display panel bright spot defect correction system according to claim 1, characterized in that: The illumination unit (4) comprises an illumination light source (41), a first beam splitting prism (42) and a second beam splitting prism (43); the first beam splitting prism (42) has a transmission-reflection ratio of 1:1 and is arranged in the output light path of the illumination light source (41); the second beam splitting prism (43) has a transmission-reflection ratio of 1:1 and is arranged in the reflection light path of the first beam splitting prism (42) and is located at the confocal position of the third lens (31) and the fourth lens (32); the imaging unit (5) is arranged on the reverse extension line of the reflection light path of the first beam splitting prism (42).

8. The OLED display panel bright spot defect correction system according to claim 7, characterized in that: The illumination light source (41) is a coaxial light source or an off-axis light source.

9. The OLED display panel bright spot defect correction system according to claim 7, characterized in that: The imaging unit (5) comprises an imaging tube lens (51) and an imaging sensor (52) which are sequentially arranged on a reverse extension line of the reflection light path of the first beam splitting prism (42).

Images