1. Assembly process:

The main tools for assembly are hammers and wrenches, which are used to tighten the frame feet. The sequence of assembly operations is to first place all tools and raw materials in an orderly manner on the workbench. Next, place the shell correctly on the workbench according to the process card instructions. If there are assembly fixtures, place them on the fixtures as required, paying attention to the correct orientation of the shell. Next, remove the protective film from the LCD screen, wipe the electrodes clean with dust-free paper, confirm the direction, align with the frame position according to the process card instructions, install the housing and press the zebra stripes tightly, and use a special assembly tool to fix the housing and circuit board. Pay attention to twisting the frame feet to a 450 degree angle, do not gnaw on the board or break the wire, and ensure that the frame feet are in parallel contact with the PCB board. Finally, remove the assembled finished product from the workbench, apply protective film, and place it on the turntable. Pay attention to making the screens and boards face each other to avoid scratches. The product assembly should be inspected by the inspector, and if it is found to be unqualified, it should be reassembled.

2. Assembly method:

The purpose of assembly is to match the electrodes of the screen and circuit board one by one, to achieve electrical performance coordination. However, due to the fact that the screen is not in direct contact with the circuit board and uses conductive adhesive strips as a medium, the screen and board cannot be visually matched, resulting in misalignment between their corresponding electrodes. The connection of the corresponding electrodes between the screen and the circuit board during the assembly process is called alignment. In assembly, the alignment between the screen and the board, as well as the alignment between the shell and the board, is mainly used to achieve the correspondence between the screen and the board during assembly. As an intermediate medium and a corresponding standard between the screen and the shell, the shell plays a significant role in alignment. The main alignment methods include edge alignment, pinhole alignment, and middle alignment.

(1) Edge alignment:

Edge alignment refers to the use of a short edge of the frame to create a one-to-one alignment standard between the LCD screen and the electrodes on the circuit board, in order to achieve assembly alignment. Edge alignment actually refers to the alignment method between the screen and the shell. Since edge alignment refers to the alignment method between the screen and the shell, there are different alignment methods for different situations of the screen and the shell. For shells, there are many situations based on different design requirements, such as symmetrical shells, shells with gaps on one side and no gaps on the other, and the direction of the shell feet. These can all be used as benchmarks for edge alignment of shells, and can be described as open edge alignment, non open edge alignment, and straight edge alignment. The alignment edges of the screen only have two types: open edge alignment and non open edge alignment, so they are often referred to as open edge alignment and non open edge alignment. When they are combined together, the combination of the two is used, such as: the sealing edge of the screen is at the opening edge of the shell, the non sealed edge of the screen is at the non opening edge of the shell, and the opening edge of the screen is at the edge of the shell. Based on the alignment methods of some screens mentioned above, combined with the alignment methods of circuit boards and shells, such as assembling with one or two shell legs of the shell as the alignment reference. This completes the assembly based on edge alignment, which is suitable for modules with wider electrodes.

(2) Middle alignment:

In addition to edge alignment and pinhole alignment, there is another alignment method called middle alignment. When designing, design the shell as a symmetrical shell. Place the LCD screen based on the long side of the shell or the gap at the short side, so that the screen is in the middle of the entire shell, and the bisector of the long side of the screen coincides with the bisector of the long side of the shell. When placing the circuit board, use the two outermost assembly holes on the same side of the circuit board or the positioning holes on the circuit board that coincide with the positioning protrusions on the shell as the positioning reference with the shell, in order to achieve assembly alignment.

1. LCM assembly techniques:

In long-term production practice, with the increase of assembly times and the accumulation of experience, many assembly techniques can be gradually mastered (assembly techniques are important in assembly production).

(1) Improve the yield rate:

In module assembly production, the yield rate is an important parameter for assessing production efficiency and the technical level of an assembly personnel. A high yield rate is necessary to improve production efficiency, ensure work completion time, reduce necessary labor time, and lower labor costs. Additionally, it can ensure the reliability of the module.

(2) Reduce waste and lower costs:

If a module is assembled multiple times, it may increase its material consumption. Scratches on the screen, shell, and paint peeling are mainly caused by deformation of the shell feet, reducing their expected stress, which affects the reliability of the module. If there are good assembly techniques to ensure the yield of modules and reduce the number of assembly times, the cost of screens and shells can be reduced.

2. Experience and principles:

Skills are techniques that accumulate experience in production and then refine it. The skills of assembly come from production and are the accumulation and summary of experience, so it is necessary to have a certain amount of experience. Without experience and knowledge of assembly principles, it is impossible to have good skills. The assembly principle is simply to make the electrodes of the LCD screen correspond one-to-one with the corresponding control electrodes on the circuit board. Based on experience and principles, fully utilize assembly techniques to promote production. Assembly techniques are extremely useful in overcoming the alignment difficulties caused by raw materials. Due to the unqualified raw materials such as shells, screens, and circuit boards, their alignment methods have become ineffective, making it impossible to assemble according to the original procedures and process documents. In other words, the assembly at this time is blind. For the alignment difficulties caused by these reasons, two main techniques are adopted to solve them. One is to search for the alignment benchmark again; The second is visual alignment. Additionally, there is the use of tooling for alignment.

(1) Re search for the alignment benchmark

Sometimes, due to raw material reasons or accumulated tolerances, the alignment reference between the screen and the shell or between the shell and the plate specified in the original process documents fails, and it is necessary to search for a new alignment reference in production to achieve assembly positioning. Before searching for the alignment benchmark again, it is necessary to analyze the reasons for the failure of the alignment benchmark and find solutions in order to achieve targeted and smooth production. The main reasons for the failure of the alignment benchmark are the three basic assembly materials of the shell, screen, and circuit board.

The most common type of alignment benchmark failure is caused by the shell, which is mainly manifested by the excessive positive tolerance of the long side of the shell, exceeding the width of one electrode, resulting in edge alignment failure. The pinhole position is incorrect and cannot be aligned. The wide edge is too long, which creates a certain angle on the screen and causes electrode misalignment. The long side of the shell is too long, resulting in an increase in positive tolerance. Since the electrode width of the screen and board is constant, if edge alignment is used, it will cause excessive displacement of the screen electrode beyond the design. When the displacement exceeds one electrode, assembling according to edge alignment will inevitably result in misalignment of the screen and board electrodes, leading to assembly failure. At this point, it is necessary to reconfirm its alignment benchmark. There are two benchmarks for assembly alignment, one is the alignment between the screen and the shell; Another is the alignment between the shell and the circuit board. Due to the fact that the alignment reference between the shell and the circuit board is often based on the shell foot for edge alignment, edge alignment can still be used to ensure that one side of the screen is tightly attached to the shell; But when changing the alignment benchmark between the shell and the circuit board, the selection of shell legs should be determined based on experiments.

If the difficulty in alignment is caused by inaccurate pinholes in the shell, due to the failure of the alignment reference between the screen and the shell, the alignment reference between the shell and the circuit board needs to be changed accordingly for the same edge alignment. Instead of aligning the pinholes between the circuit board and the shell on the same axis, the circuit board should be moved in the same direction relative to the shell with a positive tolerance to compensate for the electrode gap caused by the tolerance and achieve alignment.