A device for detecting abnormal PS column quantity in a liquid crystal panel

Abstract

This utility model relates to a device for detecting abnormal PS pillar measurements in liquid crystal panels, belonging to the field of PS pillar detection. The imaging device is mounted on a piezoelectric ceramic nano-displacement stage and includes a camera, an imaging mirror turret, a beam splitter, and an objective lens turret arranged sequentially along the Z-axis, as well as a light source assembly located on one side of the beam splitter. The imaging mirror turret has multiple imaging mirrors of different magnifications, and the objective lens turret has multiple objective lenses of different magnifications. Both the imaging mirror turret and the objective lens turret are motorized. This utility model's detection device features high detection efficiency, high stability, and high accuracy, and is suitable for three-dimensional measurement in PS pillar mass production lines, thereby reducing labor costs and improving production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of PS column detection, specifically to a device for detecting abnormal PS column quantity in a liquid crystal panel. Background Technology

[0002] The "pillar-like spacers" in LCD panels are called PS (Photo Spacers). Essentially, they are micron-sized elastic pillars created between pixels using photolithography. These precise mechanical structures maintain the thickness of the liquid crystal layer, ensuring display quality and panel reliability. They are an indispensable "invisible skeleton" in modern LCD technology, directly affecting the screen's pressure resistance, uniformity, and lifespan. An LCD panel consists of two glass substrates (TFT array substrate + color filter substrate) bonded together, with liquid crystal filling the space between them. The core function of the PS pillars is to form a precise and uniform physical support between the two substrates, ensuring: 1. Stable cell gap: Maintaining a consistent liquid crystal layer thickness (typically 3-5 microns), avoiding uneven display (such as brightness patches and color shift); 2. Pressure resistance: When the screen is subjected to pressure (such as finger pressure), the PS pillars provide elastic support, preventing substrate collisions or permanent deformation; 3. Prevention of liquid leakage: Uniform support prevents liquid crystal leakage caused by adhesive failure.

[0003] In the precision manufacturing system of liquid crystal displays, the three-dimensional morphological measurement of PS pillars is a core step in ensuring panel performance. The geometric accuracy of these micron-level pillars (typically 0.5-5μm in height and 10-20μm in diameter) directly determines the uniformity of the liquid crystal cell thickness. Through three-dimensional morphological reconstruction, key parameters that traditional two-dimensional inspection cannot capture can be obtained: 1. Height non-uniformity can lead to fluctuations in liquid crystal cell thickness, causing color shift / Mura (display patches); 2. Pillar tilting / deformation can lead to a decrease in local compressive strength, resulting in permanent water ripples after pressing; 3. Deviations in top flatness can lead to stress concentration, increasing the risk of glass substrate breakage.

[0004] Currently, the main methods for 3D measurement of PS columns include laser confocal microscopy, atomic force microscopy (AFM), X-ray CT, and white light interferometry (WLI). Among these, laser confocal microscopy uses focal tomography, which can resolve transparent materials but is limited by scanning speed (minutes / area), making it suitable for offline sampling. AFM uses probe-contact scanning, offering sub-nanometer resolution but with extremely low efficiency (hours / sample), making it suitable for R&D laboratories. X-ray CT uses tomographic scanning for 3D reconstruction, capable of revealing internal structures but difficult to integrate with mass production environments, making it suitable for failure analysis. In contrast, white light interferometry uses coherent light phase difference to reconstruct the morphology, offering three core advantages: nanometer-level precision, non-contact high-speed scanning, and resolution of complex morphologies, making it the preferred solution for 3D measurement in PS column mass production lines.

[0005] Currently, white light interferometers are only suitable for single-piece inspection, and there is no white light interferometric inspection equipment suitable for mass production lines. Utility Model Content

[0006] The technical problem to be solved by this invention is how to detect abnormal PS column counts in LCD panels on a mass production line.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A liquid crystal panel PS column abnormality detection device includes an imaging device and a piezoelectric ceramic nano-displacement stage. The imaging device is installed on the piezoelectric ceramic nano-displacement stage. The imaging device includes a camera, an imaging mirror turret, a beam splitter and an objective lens turret arranged sequentially along the Z direction, and a light source assembly located on one side of the beam splitter. The imaging mirror turret is provided with a plurality of imaging mirrors with different magnifications, and the objective lens turret is provided with a plurality of objective lenses with different magnifications. Both the imaging mirror turret and the objective lens turret are motorized turrets.

[0008] The beneficial effects of this invention are as follows: By switching between the imaging mirror turret and objective lens turret with electric switching, different magnifications of the imaging mirror and objective lens can be achieved, enabling multi-field imaging adaptation and allowing for the measurement and inspection of PS columns for different products. The piezoelectric ceramic nano-displacement stage generates nanometer-precision stepping motion, driving the imaging device to move along the Z-axis, thereby achieving layer-by-layer scanning imaging from the bottom to the top of the sample surface, ensuring movement accuracy and stability. The detection device of this invention has high detection efficiency, high stability, and high accuracy, and is suitable for three-dimensional measurement in PS column mass production lines, thereby reducing labor costs and improving production efficiency.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the light source assembly includes a light source and a shaping lens group arranged sequentially along the X direction.

[0011] Furthermore, the light source is a white LED broadband light source.

[0012] Furthermore, the camera is a high-speed, high-resolution area array CCD camera.

[0013] Furthermore, there are four imaging mirrors.

[0014] Furthermore, the magnifications of the four imaging mirrors are 0.5, 0.75, 1, and 2, respectively.

[0015] Furthermore, there are three objectives.

[0016] Furthermore, the magnifications of the three objectives are 10, 20, and 50, respectively.

[0017] Furthermore, the LCD panel PS column abnormality detection device also includes a moving mechanism, on which the piezoelectric ceramic nano-displacement stage is fixed.

[0018] The beneficial effect of adopting the above-mentioned further solution is that the moving mechanism can first drive the piezoelectric ceramic nano-displacement stage and imaging equipment to the detection point to be detected, and then use the piezoelectric ceramic nano-displacement stage to achieve high-precision scanning in the Z direction.

[0019] Furthermore, the moving mechanism is a three-degree-of-freedom moving stage. Attached Figure Description

[0020] Figure 1 This is a three-dimensional diagram of a liquid crystal panel PS column abnormality detection device according to the present invention; Figure 2 This is a schematic diagram of a liquid crystal panel PS column abnormality detection device according to the present invention.

[0021] The attached diagram lists the components represented by each number as follows: 1. Light source; 2. Shaping lens assembly; 3. Imaging lens; 4. Camera; 5. Piezoelectric ceramic nano-displacement stage; 6. Imaging lens turret; 7. Objective lens; 8. Objective lens turret; 9. Beam splitter. Detailed Implementation

[0022] The principles and features of this utility model are described below. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0023] Example 1 like Figures 1-2 As shown, this embodiment provides a device for detecting abnormal PS column quantity in a liquid crystal panel, including an imaging device and a piezoelectric ceramic nano-displacement stage 5. The imaging device is mounted on the piezoelectric ceramic nano-displacement stage 5. The imaging device includes a camera 4, an imaging mirror turret 6, a beam splitter 9, and an objective lens turret 8 arranged sequentially along the Z direction, as well as a light source assembly located on one side of the beam splitter 9. The imaging mirror turret 6 is provided with multiple imaging mirrors 3 of different magnifications, and the objective lens turret 8 is provided with multiple objective lenses 7 of different magnifications. Both the imaging mirror turret 6 and the objective lens turret 8 are motorized turrets.

[0024] In this embodiment, the imaging mirror turret 6 and objective mirror turret 8, which are electrically switchable, allow for switching between imaging mirrors 3 and objective lenses 7 at different magnifications, enabling multi-field imaging adaptation and allowing for the measurement and inspection of PS columns for different products. The piezoelectric ceramic nanostage 5 generates nanometer-precision stepping motion, driving the imaging device to move along the Z-axis, thereby achieving layer-by-layer scanning imaging from the bottom to the top of the sample surface, ensuring movement accuracy and stability. This invention's detection device boasts high detection efficiency, high stability, and high accuracy, making it suitable for three-dimensional measurement in PS column mass production lines, thereby reducing labor costs and improving production efficiency.

[0025] Specifically, such as Figure 2 As shown, the principle of white light interferometry is to use low-coherence broadband light as the light source. The broadband white light interference signal is composed of the superposition of multiple cosine functions with different periods, and its visibility is not constant, varying with different scanning positions. Interference fringes are obtained by converging the measurement light reflected from the surface of the structure under test with the reference light in the interference objective (objective 7) through the interference optical path. When the optical path difference between the measurement light and the reference light is zero, the interference signal reaches its maximum value. By finding the longitudinal height information corresponding to the extreme light intensity, the Z-axis height information of the object under test is detected. Hundreds of interference fringe images are obtained by scanning layer by layer from the bottom to the top of the sample surface within the field of view; the position of each pixel at the point of maximum light intensity is found during this process, and 3D reconstruction is completed; based on the reconstructed 3D image, relevant parameters such as the PS column height are measured.

[0026] Among them, the electric turret refers to a turret driven by a motor, which has multiple mounting holes for mounting the imaging lens 3 or the objective lens 7. The turret can rotate, so that each turret can rotate one of the mounting holes to the Z-direction downward of the camera 4. The imaging lens turret 6 and the objective lens turret 8 place one of the imaging lenses 3 and one of the objective lenses 7 in the optical path to realize the switching of the magnification of the imaging lens 3 or the objective lens 7.

[0027] Based on the above technical solution, the light source assembly includes a light source 1 and a shaping mirror group 2 arranged sequentially along the X direction.

[0028] Based on the above technical solution, the light source 1 is a white LED broadband light source.

[0029] Based on the above technical solution, the camera 4 is a high-speed, high-resolution area array CCD camera.

[0030] Based on the above technical solution, there are four imaging mirrors 3.

[0031] Based on the above technical solution, preferably, the magnifications of the four imaging mirrors 3 are 0.5, 0.75, 1 and 2, respectively.

[0032] Alternatively, the imaging lens 3 can be of other numbers or magnifications.

[0033] Based on the above technical solution, there are three objectives 7.

[0034] Based on the above technical solution, preferably, the magnifications of the three objectives 7 are 10, 20 and 50, respectively.

[0035] Alternatively, objective 7 can be of other numbers or magnifications.

[0036] In one specific example, objective lens 7 can be selected with a magnification of 10X / 20X / 50X, imaging lens 3 can be selected with a magnification of 0.5X / 0.75X / 1X / 2X, and the final combined detection magnification can be 5X / 7.5X / 10X / 15X / 20X / 25X / 37.5X / 40X / 50X / 100X.

[0037] Based on the above technical solution, the LCD panel PS column abnormality detection device also includes a moving mechanism, and the piezoelectric ceramic nano displacement stage 5 is fixed on the moving mechanism.

[0038] The moving mechanism can first move the piezoelectric ceramic nano-displacement stage 5 and the imaging device to the detection point that needs to be detected, and then use the piezoelectric ceramic nano-displacement stage 5 to achieve high-precision scanning in the Z direction.

[0039] Optionally, the moving mechanism is a two-degree-of-freedom moving stage, which can drive the piezoelectric ceramic nano-displacement stage 5 and the imaging device to move along the X and Y directions; or the moving mechanism is a three-degree-of-freedom moving stage, which can drive the piezoelectric ceramic nano-displacement stage 5 and the imaging device to move along the X, Y and Z directions.

[0040] Specifically, the three-degree-of-freedom moving stage includes an X-axis linear stage, a Y-axis linear moving stage, and a Z-axis linear moving stage. The Y-axis linear moving stage is fixed on the slide of the X-axis linear stage, the Z-axis linear moving stage is fixed on the slide of the Y-axis linear moving stage, and the piezoelectric ceramic nano-displacement stage 5 is fixed on the slide of the Z-axis linear moving stage.

[0041] This invention relates to a device for detecting anomalies in PS columns of liquid crystal panels using white light interference. Through the synergistic effect of a broadband coherent light source and phase-shifting interferometry, it achieves non-contact three-dimensional morphology reconstruction of micron-level optical spacers. This resolves the contradictions between efficiency, accuracy, and industrial adaptability in existing technologies (AFM / laser confocal microscopy), providing a solution for liquid crystal panel microstructures that combines sub-nanometer resolution with online mass production testing capabilities.

[0042] The core of this device's optical system utilizes a white LED broadband light source, coupled with a high-speed, high-resolution area array camera. Multiple imaging fields of view are achieved through electrically switchable objective lens groups (10X / 20X / 50X selectable) and imaging lens groups (0.5X / 0.75X / 1X / 2X selectable), covering an imaging field of view from 51.2×38.4μm to 1024×768μm. The system integrates a PZT piezoelectric ceramic nanostage, providing a maximum scanning range of ≤100μm and supporting a high-speed scanning mode of 80μm / s. It maintains a vertical resolution of 0.1nm throughout the scanning process, and its core performance indicators meet the requirements for three-dimensional nanometer-precision detection of micron-level optical spacers (PS columns). (1) Single-point scanning speed is less than 1 second; (2) The static three-fold variance of the PS column height is ≤18nm; (3) The dynamic three-fold variance of the PS column height is ≤18nm; (4) The static three-fold variance 3σ of the CD value of the PS column is ≤200nm; (5) The dynamic three-fold variance of the CD value of the PS column is 3σ≤200nm.

[0043] Example 2 This embodiment also provides a method for detecting abnormal PS column quantity in a liquid crystal panel, which is implemented using the liquid crystal panel PS column abnormal quantity detection device described in Embodiment 1, and includes the following steps: S1, Select several detection points in the area to be tested of the sample; S2, the imaging device and the piezoelectric ceramic nano-displacement stage 5 are moved above one of the detection points; S3, the piezoelectric ceramic nano-displacement stage 5 drives the imaging device to move along the Z direction, thereby scanning layer by layer from the bottom to the top of the sample surface within the field of view. The camera 4 acquires the interference fringe image information of each layer, and the PS column detection result at the detection point is obtained by analyzing the interference fringe image information of each layer. S4. Repeat S2 and S3 until all detection points have been detected.

[0044] In this embodiment, the PS pillar detection method for liquid crystal panels mainly involves selecting points for detection in each region, thereby improving detection efficiency. The aforementioned detection device offers high detection efficiency, high stability, and high accuracy, making it particularly suitable for three-dimensional measurement in PS pillar mass production lines.

[0045] Specifically, during the detection of PS column anomalies in LCD panels, dozens to thousands of points are selected on a large 1850mm×1500mm plate according to requirements. Algorithm templates are selected based on the shape of these points from different sample tests; currently, cylindrical shapes are the most commonly tested. A moving mechanism moves the piezoelectric ceramic nano-displacement stage 5 and the imaging device above the detection point. The piezoelectric ceramic nano-displacement stage 5 then drives the imaging device to move in the Z-axis, scanning layer by layer from the bottom to the top of the sample surface within the field of view. Based on the positioning information of the piezoelectric ceramic nano-displacement stage 5, the camera 4 is triggered to take images every 50nm (Z-axis displacement), obtaining hundreds of interference fringe images. An algorithm is used to find the position of each pixel when the light intensity is at its maximum during this process, completing 3D reconstruction. Based on the reconstructed 3D image, the height of the PS column and other related parameters are measured and the results are output.

[0046] Camera 4 is a high-speed, high-resolution area array camera that scans and images the PS pillars of the product. Light source 1 uses a high-power white light source; its bandwidth, stability, and spectral characteristics directly determine the accuracy, resolution, and reliability of the white light measurement. A piezoelectric ceramic nano-displacement stage 5 is used as the driving source to generate nanometer-precision stepping motion. The piezoelectric ceramic nano-displacement stage 5 can directly drive the imaging equipment for micro-displacement adjustment, and its moving surface has threaded holes for mounting and fixing the imaging equipment. The optical imaging lens (imaging lens 3 + objective lens 7) enables the product information to be imaged onto the CCD of the area array camera. Since the PS pillar shapes and sizes of LCD panel products vary, this invention designs a combination of imaging lens 3 and objective lens 7 with different magnifications to meet testing requirements, and incorporates an adaptive electric turret to further industrialize the testing process.

[0047] In the description of this utility model, it should be noted that the terms "X direction", "Y direction", "Z direction", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0048] In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0051] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A liquid crystal panel PS column abnormality amount detection device characterized by comprising: The device includes an imaging device and a piezoelectric ceramic nano-displacement stage (5). The imaging device is mounted on the piezoelectric ceramic nano-displacement stage (5). The imaging device includes a camera (4), an imaging mirror turret (6), a beam splitter (9), and an objective lens turret (8) arranged sequentially along the Z direction, as well as a light source assembly located on one side of the beam splitter (9). The imaging mirror turret (6) is provided with multiple imaging mirrors (3) of different magnifications, and the objective lens turret (8) is provided with multiple objective lenses (7) of different magnifications. Both the imaging mirror turret (6) and the objective lens turret (8) are motorized turrets.

2. The liquid crystal panel PS column abnormality amount detection device according to claim 1, characterized by The light source assembly includes a light source (1) and a reshaping lens assembly (2) arranged sequentially along the X direction.

3. The liquid crystal panel PS column abnormality amount detection device according to claim 2, characterized by The light source (1) is a white LED broadband light source.

4. The liquid crystal panel PS column abnormality amount detection device according to claim 1, characterized by The camera (4) is a high-speed, high-resolution area array CCD camera.

5. The liquid crystal panel PS column abnormality amount detection device according to claim 1, characterized by There are four imaging mirrors (3).

6. The liquid crystal panel PS column abnormality amount detection device according to claim 5, characterized by The magnifications of the four imaging mirrors (3) are 0.5, 0.75, 1 and 2, respectively.

7. The liquid crystal panel PS column abnormality amount detection device according to claim 1, characterized by There are three objectives (7).

8. The liquid crystal panel PS column abnormality amount detection device according to claim 7, characterized by The magnifications of the three objectives (7) are 10, 20 and 50, respectively.

9. The liquid crystal panel PS column abnormality amount detection device according to claim 1, characterized by It also includes a moving mechanism, on which the piezoelectric ceramic nano-displacement stage (5) is fixed.

10. The liquid crystal panel PS column abnormality amount detection device according to claim 9, characterized by The moving mechanism is a three-degree-of-freedom moving stage.

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