how to make a lcd screen factory

Important technical improvements of LCD, such as LED backlighting and wide viewing Angle, are directly related to LCD. And account for an LCD display 80% of the cost of the LCD panel, enough to show that the LCD panel is the core part of the entire display, the quality of the LCD panel, can be said to directly determine the quality of an LCD display.

The production of civil LCD displays is just an assembly process. The LCD panel, the main control circuit, shell, and other parts of the main assembly, basically will not have too complex technical problems.

Does this mean that LCDS are low-tech products? In fact, it is not. The production and manufacturing process of the LCD panels is very complicated, requiring at least 300 process processes. The whole process needs to be carried out in a dust-free environment and with precise technology.

The general structure of the LCD panel is not very complex, now the structure of the LCD panel is divided into two parts: the LCD panel and the backlight system.

Due to the LCD does not shine, so you need to use another light source to illuminate, the function of the backlight system is to this, but currently used CCFL lamp or LED backlight, don’t have the characteristics of the surface light source, so you need to guide plate, spreadsheet components, such as linear or point sources of light evenly across the surface, in order to make the entire LCD panel on the differences of luminous intensity is the same, but it is very difficult, to achieve the ideal state can be to try to reduce brightness non-uniformity, the backlight system has a lot to the test of design and workmanship.

In addition, there is a driving IC and printed circuit board beside the LCD panel, which is mainly used to control the rotation of LCD molecules in the LCD panel and the transmission of display signals. The LCD plate is thin and translucent without electricity. It is roughly shaped like a sandwich, with an LCD sandwiched between a layer of TFT glass and a layer of colored filters.

LCD with light refraction properties of solid crystals, with fluid flow characteristics at the same time, under the drive of the electrode, can be arranged in a way that, in accordance with the master want to control the strength of the light through, and then on the color filter, through the red, green, blue three colors of each pixel toning, eventually get the full-screen image.

According to the functional division, the LCD panel can be divided into the LCD panel and the backlight system. However, to produce an LCD panel, it needs to go through three complicated processes, namely, the manufacturing process of the front segment Array,the manufacturing process of the middle segment Cell, and the assembly of the rear segment module. Today we will be here, for you in detail to introduce the production of the LCD panel manufacturing process.

The manufacturing process of the LCD panel Array is mainly composed of four parts: film, yellow light, etch and peel film. If we just look at it in this way, many netizens do not understand the specific meaning of these four steps and why they do so.

First of all, the motion and arrangement of LCD molecules need electrons to drive them. Therefore, on the TFT glass, the carrier of LCD, there must be conductive parts to control the motion of LCD. In this case, we use ITO (Indium Tin Oxide) to do this.ITO is transparent and also acts as a thin-film conductive crystal so that it doesn’t block the backlight.

The different arrangement of LCD molecules and the rapid motion change can ensure that each pixel displays the corresponding color accurately and the image changes accurately and quickly, which requires the precision of LCD molecule control.ITO film needs special treatment, just like printing the circuit on the PCB board, drawing the conductive circuit on the whole LCD board.

First, the ITO film layer needs to be deposited on the TFT glass, so that there is a smooth and uniform ITO film on the whole TFT glass. Then, using ionized water, the ITO glass is cleaned and ready for the next step.

Next, a photoresist is applied to the glass on which ITO film is deposited, and a uniform photoresist layer is formed on the ITO glass. After baking for a period of time, the solvent of the photoresist was partially volatilized to increase the adhesion of the photoresist material to the ITO glass.

Ultraviolet light (UV) is used to illuminate the surface of the photoresist through a pre-made electrode pattern mask, which causes the photoresist layer to react. The photoresist is selectively exposed under ultraviolet light by covering the photoresist on the glass coated with the photoresist.

The exposed part of the photoresist is then washed away with the developer, leaving only the unexposed part, and the dissolved photoresist is then washed away with deionized water.

Then etch off the ITO film without photoresist covering with appropriate acid etching solution, and only retain the ITO film under the photoresist. ITO glass is conductive glass (In2O3 and SnO2). The ITO film not covered by photoresist is easy to react with acid, while the ITO film covered by photoresist can be retained to obtain the corresponding wire electrode.

Stripping: High concentration of alkali solution (NaOH solution) is used as a stripping solution to peel off the remaining photoresist on the glass so that ITO glass can form ITO graphics exactly consistent with the photolithography mask.

Rinse the basic label of glass with an organic solution and remove the photolithographic tape after reaction to keep the glass clean. This completes the first thin-film conductive crystal process, which generally requires at least five identical processes to form a complex and sophisticated pattern of electrodes on the glass.

This completes the previous Array process. It is not difficult to see from the whole process that ITO film is deposited, photoresist coated, exposed, developed, and etched on TFT glass, and finally, ITO electrode pattern designed in the early stage is formed on TFT glass to control the movement of LCD molecules on the glass. The general steps of the whole production process are not complicated, but the technical details and precautions are very complicated, so we will not introduce them here. Interested friends can consult relevant materials by themselves.

The glass that the LCD board uses makes a craft also very exquisite. (The manufacturing process flow of the LCD display screen)At present, the world’s largest LCD panel glass, mainly by the United States Corning, Japan Asahi glass manufacturers, located in the upstream of the production of LCD panel, these manufacturers have mastered the glass production technology patents. A few months ago, the earthquake caused a corning glass furnace shutdown incident, which has caused a certain impact on the LCD panel industry, you can see its position in the industry.

As mentioned earlier, the LCD panel is structured like a sandwich, with an LCD sandwiched between the lower TFT glass and the upper color filter. The terminal Cell process in LCD panel manufacturing involves the TFT glass being glued to the top and bottom of a colored filter, but this is not a simple bonding process that requires a lot of technical detail.

As you can see from the figure above, the glass is divided into 6 pieces of the same size. In other words, the LCD made from this glass is finally cut into 6 pieces, and the size of each piece is the final size. When the glass is cast, the specifications and sizes of each glass have been designed in advance.

Then, the organic polymer directional material is coated on the surface of the glass, that is, a uniform directional layer is applied to the appropriate position of ITO glass by the method of selective coating. Meanwhile, the directional layer is cured.

Directional friction:Flannelette material is used to rub the surface of the layer in a specific direction so that the LCD molecules can be arranged along the friction direction of the aligned layer in the future to ensure the consistency of the arrangement of LCD molecules. After the alignment friction, there will be some contaminants such as flannelette thread, which need to be washed away through a special cleaning process.

After the TFT glass substrate is cleaned, a sealant coating is applied to allow the TFT glass substrate to be bonded to the color filter and to prevent LCD outflow.

Finally, the conductive adhesive is applied to the frame in the bonding direction of the glass of the color filter to ensure that external electrons can flow into the LCD layer. Then, according to the bonding mark on the TFT glass substrate and the color filter, two pieces of glass are bonded together, and the bonding material is solidified at high temperatures to make the upper and lower glasses fit statically.

Color filters are very important components of LCD panels. Manufacturers of color filters, like glass substrate manufacturers, are upstream of LCD panel manufacturers. Their oversupply or undersupply can directly affect the production schedule of LCD panels and indirectly affect the end market.

As can be seen from the above figure, each LCD panel is left with two edges after cutting. What is it used for? You can find the answer in the later module process

Finally, a polarizer is placed on both sides of each LCD substrate, with the horizontal polarizer facing outwards and the vertical polarizer facing inwards.

A polarizer is an optical plate that allows only light from a certain direction to pass through. It is an optical element that converts natural light into straight polarized light. The mechanism of action is to make the vertical direction light pass through the straight incident light after passing through the vertical polarizer, and the other horizontal direction light is absorbed, or use reflection and scattering and other effects to make its shade.

When making LCD panel, must up and down each use one, and presents the alternating direction, when has the electric field and does not have the electric field, causes the light to produce the phase difference and to present the light and dark state, uses in the display subtitle or the pattern.

The rear Module manufacturing process is mainly the integration of the drive IC pressing of the LCD substrate and the printed circuit board. This part can transmit the display signal received from the main control circuit to the drive IC to drive the LCD molecules to rotate and display the image. In addition, the backlight part will be integrated with the LCD substrate at this stage, and the complete LCD panel is completed.

Firstly, the heteroconductive adhesive is pressed on the two edges, which allows external electrons to enter the LCD substrate layer and acts as a bridge for electronic transmission

Next is the drive IC press. The main function of the drive IC is to output the required voltage to each pixel and control the degree of torsion of the LCD molecules. The drive IC is divided into two types. The source drive IC located in the X-axis is responsible for the input of data. It is characterized by high frequency and has an image function. The gate drive IC located in the Y-axis is responsible for the degree and speed of torsion of LCD molecules, which directly affects the response time of the LCD display. However, there are already many LCD panels that only have driving IC in the X-axis direction, perhaps because the Y-axis drive IC function has been integrated and simplified.

The press of the flexible circuit board can transmit data signals and act as the bridge between the external printed circuit and LCD. It can be bent and thus becomes a flexible or flexible circuit board

The manufacturing process of the LCD substrate still has a lot of details and matters needing attention, for example, rinse with clean, dry, dry, dry, ultrasonic cleaning, exposure, development and so on and so on, all have very strict technical details and requirements, so as to produce qualified eyes panel, interested friends can consult relevant technical information by a search engine.

LCD (LC) is a kind of LCD, which has the properties of light transmission and refraction of solid Crystal, as well as the flow property of Liquid. It is because of this property that it will be applied to the display field.

However, LCD does not emit light autonomously, so the display equipment using LCD as the display medium needs to be equipped with another backlight system.

First, a backplate is needed as the carrier of the light source. The common light source for LCD display equipment is CCFL cold cathode backlight, but it has started to switch to an LED backlight, but either one needs a backplate as the carrier.

CCFL backlight has been with LCD for a long time. Compared with LED backlight, CCFL backlight has many defects. However, it has gradually evolved to save 50% of the lamp and enhance the transmittance of the LCD panel, so as to achieve the purpose of energy-saving.

With the rapid development of LED in the field of lighting, the cost has been greatly reduced.LCD panels have also started to use LED as the backlight on a large scale. Currently, in order to control costs, an LED backlight is placed on the side rather than on the backplate, which can reduce the number of LED grains.

However, no matter CCFL backlight or LED backlight is placed in various ways, the nature of the backlight source cannot be a surface light source, but a linear light source or point light source. Therefore, other components are needed to evenly distribute the light to the whole surface. This task is accomplished by the diffuser plate and diffuser plate.

On the transparent diffuser plate, point-like printing can block part of the light. The LED backlight on the side drives the light from the side of the diffuser plate, and the light reflects and refracts back and forth in the diffuser plate, distributing the light evenly to the whole surface. Point-like printing blocks part of the light, screening the light evenly like a sieve.

At the top of the diffusion plate, there will be 3~4 diffuser pieces, constantly uniform light to the whole surface, improve the uniformity of light, which is directly related to the LCD panel display effect. Professional LCD in order to better control the brightness uniformity of the screen, panel procurement, the later backlight control circuit, will make great efforts to ensure the quality of the panel.

The backlight system also includes a backlight module laminator, located behind the backplane. In the CCFL backlight era, you can often see the long strip laminator like the one above, with each coil responsible for a set of tubes.

However, it is much simpler to use a side white LED as a backlight. The small circuit board on the far left of the figure above is the backlight of the LED.

This is the general structure of the backlight system. Since I have never seen the backlight mode of R.G.B LED, I cannot tell you what the backlight mode is like. I will share it with you when I see it in the future.

Since the LCD substrate and the backlight system are not fixed by bonding, a metal or rubber frame is needed to be added to the outer layer to fix the LCD substrate and the backlight system.

After the period of the Module, the process is completed in LCM (LCDModule) factory, the core of this part of the basic does not involve the use of LCD manufacturing technology, mainly is some assembly work, so some machine panel factories such as chi mei, Korea department such as Samsung panel factory, all set with LCM factories in mainland China, Duan Mo group after the LCD panel assembly, so that we can convenient mainland area each big monitor procurement contract with LCD TV manufacturers, can reduce the human in the whole manufacturing and transportation costs.

However, neither Taiwan nor Korea has any intention to set up factories in mainland China for the LCD panel front and middle manufacturing process involving core technologies. Therefore, there is still a long way to go for China to have its own LCD panel industry.

One of today’s modern technological wonders is the flat-panel liquid crystal display (LCD) screen, which is the key component we find inside televisions, computer monitors, smartphones, and an ever-proliferating range of gadgets that display information electronically.What most people don’t realize is how complex and sophisticated the manufacturing process is. The entire world’s supply is made within two time zones in East Asia. Unless, of course, the factory proposed by Foxconn for Wisconsin actually gets built.

Last week I had the opportunity to tour BOE Technology Group’s Gen 10.5 factory in Hefei, the capital of China’s Anhui Province.This was the third factory, or “fab” that Beijing-based BOE built in Hefei alone, and in terms of capability, it is now the most advanced in the world.BOE has a total of 12 fabs in Beijing, Chongqing, and several other major cities across China; this particular factory was named Fab 9.

Liquid crystal display (LCD) screens are manufactured by assembling a sandwich of two thin sheets of glass.On one of the sheets are transistor “cells” formed by first depositing a layer of indium tin oxide (ITO), an unusual metal alloy that you can actually see through.That’s how you can get electrical signals to the middle of a screen.Then you deposit a layer of silicon, followed by a process that builds millions of precisely shaped transistor parts.This patterning step is repeated to build up tiny little cells, one for each dot (known as a pixel) on the screen.Each step has to be precisely aligned to the previous one within a few microns.Remember, the average human hair is 40 microns in diameter.

On the other sheet of glass, you make an array of millions of red, green, and blue dots in a black matrix, called a color filter array (CFA).This is how you produce the colors when you shine light through it.Then you drop tiny amounts of liquid crystal material into the cells on the first sheet and glue the two sheets together.You have to align the two sheets so the colored dots sit right on top of the cells, and you can’t be off by more than a few microns in each direction anywhere on the sheet.The sandwich is next covered with special sheets of polarizing film, and the sheets are cut into individual “panels” – a term that is used to describe the subassembly that actually goes into a TV.

For the sake of efficiency, you would like to make as many panels on a sheet as possible, within the practical limitations of how big a sheet you can handle at a time.The first modern LCD Fabs built in the early 1990s made sheets the size of a single notebook computer screen, and the size grew over time. A Gen 5 sheet, from around 2003, is 1100 x 1300 mm, while a Gen 10.5 sheet is 2940 x 3370 mm (9.6 x 11 ft).The sheets of glass are only 0.5 - 0.7 mm thick or sometimes even thinner, so as you can imagine they are extremely fragile and can really only be handled by robots.The Hefei Gen 10.5 fab is designed to produce the panels for either eight 65 inch or six 75 inch TVs on a single mother glass.If you wanted to make 110 inch TVs, you could make two of them at a time.

The fab is enormous, 1.3 km from one end to the other, divided into three large buildings connected by bridges.LCD fabs are multi-story affairs.The main equipment floor is sandwiched between a ground floor that is filled with chemical pipelines, power distribution, and air handling equipment, and a third floor that also has a lot of air handling and other mechanical equipment.The main equipment floor has to provide a very stable environment with no vibrations, so an LCD fab typically uses far more structural steel in its construction than a typical skyscraper.I visited a Gen 5 fab in Taiwan in 2003, and the plant manager there told me they used three times as much structural steel as Taipei 101, which was the world’s tallest building from 2004- 2010.Since the equipment floor is usually one or two stories up, there are large loading docks on the outside of the building.When they bring the manufacturing equipment in, they load it onto a platform and hoist it with a crane on the outside of the building.That’s one way to recognize an LCD fab from the outside – loading docks on high floors that just open to the outdoors.

LCD fabs have to maintain strict standards of cleanliness inside.Any dust particles in the air could cause defects in the finished displays – tiny dark spots or uneven intensities on your screen.That means the air is passed through elaborate filtration systems and pushed downwards from the ceiling constantly.Workers have to wear special clean room protective clothing and scrub before entering to minimize dust particles or other contamination.People are the largest source of particles, from shedding dead skin cells, dust from cosmetic powders, or smoke particles exhaled from the lungs of workers who smoke.Clean rooms are rated by the number of particles per cubic meter of air.A class 100 cleanroom has less than 100 particles less than 0.3 microns in diameter per cubic meter of air, Class 10 has less than 10 particles, and so on. Fab 9 has hundeds of thousands of square meters of Class 100 cleanroom, and many critical areas like photolithography are Class 10.In comparison, the air in Harvard Square in Cambridge, MA is roughly Class 8,000,000, and probably gets substantially worse when an MBTA bus passes through.

Since most display manufacturing has to be done in a cleanroom and handling the glass requires such precision, the factory is heavily automated.As you watch the glass come in, it is placed into giant cassettes by robot handlers, and the cassettes are moved around throughout the factory.At each step, robots lift a piece of glass out of the cassette, and position it for the processing machines.Some of the machines, like the ones that deposit silicon or ITO, orient the glass vertically, and put them inside an enormous vacuum chamber where all the air is first pumped out before they can go to work.And then they somehow manage to deposit micrometer thin layers that are extremely uniform.It is a miracle that any of this stuff actually works.

It obviously costs a lot to equip and run such a fab.Including all of the specialized production tools, press reports say BOE spent RMB 46 billion (US$6.95 billion). Even though you don’t see a lot of people on the floor, it takes thousands of engineers to keep the place running.

The Hefei Gen 10.5 is one of the most sophisticated manufacturing plants in the world.On opening day for the fab, BOE shipped panels to Sony, Samsung Electronics, LG Electronics, Vizio, and Haier.So if you have a new 65 or 75-inch TV, there is some chance the LCD panel came from here.

Liquid crystal displays are commonly known as LCD, consist of liquid crystals that are activated by electric current, and they are used to display lines of alpha-numeric information (one or more lines) in a variety of devices, for example, fax machines, answering machines call counters, laptop computer screens, scientific instruments, portablecompact disc players,clocks, and so forth. The basis of LCD technology is the liquid crystal, a substance made of complicated molecules.

LCD uses a liquid crystal to produce a visible image. Liquid crystal displays are super-thin technology display screens that are generally used in laptop computer screens, TVs, cell phones, and portable video games.Liquid crystal displays (LCDs) have become the dominant technology in televisions and monitors in our homes and offices.

In an LCD, an electric current is used to switch segments of liquid crystals from a transparent phase to a cloudy phase, each segment forming part of a number or letter. The segments can also be in the shape of tiny dots or pixels, and they can be arranged in rows and columns. They are turned on and off individually to either block or allow polarized light to pass through. When the light is blocked, a dark spot is created on the reflecting screen.

The input of ITO glass: According to the requirements of the product, appropriate ITO glass is selected and put into the transfer basket. Specifications and models of ITO glass are required to meet the requirements of the product. Remember that the ITO layer must be inserted into the basket upward.

Liquid crystal display (LCD) screens are manufactured by assembling a sandwich of two thin sheets of glass.  On one of the sheets are transistor “cells” formed by first depositing a layer of indium tin oxide (ITO), an unusual metal alloy that you can actually see through.  That’s how you can get electrical signals to the middle of a screen.  Then you deposit a layer of silicon, followed by a process that builds millions of precisely shaped transistor parts.  This patterning step is repeated to build up tiny little cells, one for each dot (known as a pixel) on the screen.  Each step has to be precisely aligned to the previous one within a few microns. Remember, the average human hair is 40 microns in diameter.

On the other sheet of glass, you make an array of millions of red, green, and blue dots in a black matrix called a color filter array (CFA). This is how you produce the colors when you shine light through them.  Then you drop tiny amounts of liquid crystal material into the cells on the first sheet and glue the two sheets together.  You have to align the two sheets so the colored dots sit right on top of the cells, and you can’t be off by more than a few microns in each direction anywhere on the sheet.  The sandwich is next covered with special sheets of the polarizing film, and the sheets are cut into individual “panels” – a term that is used to describe the subassembly that actually goes into a TV.

Clean ITO glass with the cleaning agent and deionized water (DI water), wash impurities and oil stains on the ITO surface with physical or chemical methods and then remove and dry the water to ensure the processing quality of the next process.

According to product requirements, prepare ITO glass (thickness, surface resistance, substrate type) suitable for cleaning. The front of the glass is placed in the same direction, that is, the identification angles of all the glass to be cleaned are placed in the same direction. Work in the same direction.

Photoresist Glue coatingis the first process ofphotolithography. It is to coat a layer of photoresist evenly on the ITO surface of ITO glass. The effect of coating directly affects the quality of photolithography. Its main control content is photoresist Preparation, coating thickness, and uniformity, coating surface state, etc.

Evenly coat a layer of photoresist on the conductive surface of ITO glass. The glass coated with a photoresist must be pretreated at a certain temperature.

Duringexposure,the mask and photoresist will not damage the photoresist film and contaminate the mask film even if they are in contact with each other. At the same time, only when the photoresist is clean, can the photoresist fully react with light during exposure.

Ultraviolet light (UV) is used to illuminate the surface of the photoresist through the premade electrode pattern mask, which causes the reaction of the photoresist layer. The photoresist is selectively exposed under an ultraviolet lamp by covering the photoresist on the glass coated with the photoresist (as shown in the figure).

Process control:temperature, time (pulling speed) exposure Use ultraviolet light to irradiate the photoresist surface through the premade film (selective irradiation) to make the photoresist layer of the part irradiated by the ultraviolet light react.

The surface of the glass is treated with developer solution, the photoresist layer decomposed by light is removed, the photoresist layer of the unexposed part is retained, the photoresist of the part exposed by UV light is dissolved in the developer solution by chemical method, the developed glass has to undergo a certain temperature hardening film treatment.

The photoresist is selectively exposed under the ultraviolet light development Treat the surface of the glass with a developer solution, remove the photoresist layer (positive glue) that has been decomposed by light, leave the unexposed part of the photoresist layer, and use the photolithography of the part irradiated with UV light to dissolve in the developer solution.

Since the photoresist film softens and swells during development, which affects the anti-corrosion ability of the film, the glass must be baked at an appropriate temperature after development to remove moisture and enhance the adhesion of the film to the glass. This process is called hard film.

Hard film conditions: one is temperature, and the other is time (drawing speed). Generally, hard film conditions are higher than pre-baking conditions.

Use a certain ratio of acid to remove the ITO film on the glass that is not protected by the photoresist, and leave the ITO protected by the photoresist, and finally form the desired pattern.

As shown in the figure, the etching solutionused should generally be able to etch away the ITO without damaging the photoresist on the glass surface. Generally, a certain proportion of HCl, HNO3 (or FeCl3), and a mixture of water are used.

Etching is traditionally the process ofusing strong acid or mordant to cut into the unprotected parts of a metal surfaceto create a design in intaglio (incised) in the metal. … The plate is then dipped in a bath of acid, known as the mordant (French for “biting”) or etchant, or has acid washed over it.

With an appropriate acid etching solution, the ITO film without photoresist covering is etched off. Thus, the required ITO electrode pattern is obtained.

Use high-concentration lye as a stripping solution to peel off the remaining photoresist on the glass, so that an ITO pattern that is exactly the same as the film pattern is formed on the ITO glass, as shown in the figure below.

Generally, a brush is used toscrubat the same time to enhance the stripping effect. Then use DI water to clean and dry the glue crumbs. Generally, the above processes are calledlithography processes, which play a key role in LCD manufacturing.

the high concentration of alkali solution (NaOH solution) is used as the film removal solution to peel off the remaining photoresist on the glass, thus forming ITO graphics exactly consistent with the lithography mask on the ITO glass.

According to product requirements, prepare ITO glass (thickness, surface resistance, substrate type) suitable for cleaning. The front of the glass is placed in the same direction, that is, the identification angles of all the glass to be cleaned are placed in the same direction. Work in the same direction.

Generally, the orientation materials for the production of low- and medium-grade LCDs are made of PA, that is, polyimide acid, which is made by the polymerization reaction of dianhydride and diamine at low temperature. It is dehydrated and cured at high temperature (the upper chemical layer is a kind of ring Chemical reaction), it becomes polyimide (PI). Polyimide has good chemical stability, excellent mechanical properties, high insulation, high-temperature resistance, high dielectric constant, radiation resistance, and non-flammability.

Screen printing is used for seal printing and thick layer printing. Flexo-Printing is used for polyimide layer printing and printing of thin layers with high precision.

Screen printing is a technology, where the print material is pressed by a squeegee through a mesh that is fixed on a frame. The mesh carries a photoresist layer with openings defining the pattern to be printed.

Flexo printing is offered in order to form polyimide layers in glass plates for LCD manufacturing. We can integrate these machines in an in-line production street or in a polyimide cluster, consisting of a polyimide printing machine, a coupled hot plate curing system and related automation incl. loading and unloading devices.

The purpose of the pre-baking is to promote the full volatilization of the solvent in the adhesive film and to dry the adhesive film to enhance the adhesion between the adhesive film and the ITO glass surface and the wear resistance of the adhesive film.

The glass coated with a photoresist is baked for a period of time at a certain temperature to volatilize the solvent in the photoresist and increase its adhesion to the glass surface. the glass will be processed by high temperature again, making the photoresist stronger.

Use flannel materials to rub the surface of the alignment layer in a specific direction so that the liquid crystal molecules can be aligned along the rubbing direction of the alignment layer in the future.

Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.

Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.

Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.

Punctuation silkscreen is used to connect the circuits of the LCD because there are 2 glasses of the LCD. up one and down. Only the pin side glass has an electricity connection, that dots are for supplying electricity for the glass which doesn’t have electricity. that dots are for supplying electricity for the glass which doesn’t have electricity.

The system of roller lamination is that after an inclined stage which sucks and holds the film, then touches the roller at the film tip portion, and laminates the film to the cover glass by roller pressure and the movement of the lamination stage. The screen lamination system is a method of entirely sucking and holding the film in an adsorption mesh sheet and laminating it by a roller pressure through a mesh.

As described above already, the seal has to be finally cured after the cell assembly process. This has to be done under pressure in order to make sure that the seal thickness is properly related to the spacer diameter and the calculated liquid crystal thickness can be reached with low tolerances. Hotpress ovens are available as a batch process tool and as a single panel press oven. The batch oven requires a previous collection of panels and preparation of a larger pile of panels that are pressed together. The pressed pile of wafers is then cured in a clean convection oven. The single panel hot press oven is easier to integrate with automatic lines and works continuously.

Usually, a pair of ITO glasses can make multiple liquid crystal cells. In order to expose the LCD filling port, the glass must be appropriately cut into strips or granules.

The two glass substrates must be cut to the proper size, polished, and washed. Cutting can be done with a diamond saw or scribe while polishing involves a process called lapping, in which the glass is held against a rotating wheel that has abrasive particles embedded in it.

This stage includes filling the liquid crystal into the prepared empty cell and sealing the filling hole so that the liquid crystal cell is basically made. Generally, a special liquid crystal filling machine is used to form a vacuum in the liquid crystal cell, and then the liquid crystal is filled into the LCD cell by the pressure difference and the capillary action of the liquid crystal cell.

Use a sealing material (such as a sealing resin) to block the opening of the filled liquid crystal box. Wipe clean the liquid crystal on the sealing surface of the filled LC liquid crystal box, apply a certain amount of UV sealing glue, and then irradiate it with ultraviolet rays to cause the glue itself to chemically react and interact.Coupling and polymerizationto form a firm seal to prevent the liquid crystal in the screen from leaking to the outside, and also prevent external contaminants from intruding into the liquid crystal in the screen.

Detection Visuallyinspects the appearance and background color of semi-finished LCD products under the polarized light table and picks out the unqualified products.

The electrical testis to check the display graphics, electrical and functional defects, and other appearance defects of the LCD screen under the power-on state.

This is the most important point in LCD manufacturing, where silkscreens are used for printing. High-resolution silkscreens have more than 130 meshes per cm, enabling them to print lines with a width down to 50µm. The layer thickness is in the range of 10µm normally, which is regarded as a “thick” layer in LCD manufacturing.

For creating the image, the mesh is coated by a photosensitive emulsion, which is exposed using a mask, made from a glass or polymer film. The unexposed portion of the coating is washed off afterward. This portion lets the seal material go through and you have its pattern on the substrate.

Adhesive force enhancement. This surface improvement is used for various materials like plastics, metals, and inorganic compounds. It can be used for many applications e.g before like aquarium tank sealing, sticking or mounting plastic parts or rubbers, before attachment of aluminum foils in micro condensers, mounting of magnetic heads, semiconductor lead frames, etc.

Coating property enhancement. This effect is used for mudguards, fender frames, and airbags in cars, propulsion coils for superconductive linear motor cars, outdoor structures for power facilities, etc.

Liquid Crystal Displays or more commonly known as LCDs are one of the most common electronic components which help us interact with an equipment or a device. Most personal portable equipment and even gigantic industrial equipment utilize a custom segment display to display data. For many portable consumer electronics, a segment LCD display is one of the biggest contributors to the overall cost of the device, hence designing a custom segment display can drive the cost down while also utilizing the display area in the most optimum manner. These displays have the lowest cost per piece, low power requirements, and a low tooling fee too.

At first thought, designing a custom segment LCD might look like a Herculean task, but trust me that it is easier than it seems. In this article, we have summarised and compared the display types and available technologies which are required to construct a custom segment LCD. We have also provided a flowchart that can act as a step-by-step guide while you design your own custom LCD. We have also provided the process we followed, a require gathering sheet we used for communicating our needs to the manufacturer, and a few other data and the quotation we received from the manufacturer.

Icons: A silhouette of any shape can be placed on the glass which enhances the ability to display data. For example, a symbol of a heart can be made to denote heart rate or an icon for a low battery to show that the battery needs to be charged. Icons are counted as a single pixel or segment and can give a lot more details than similar-sized text.

LCD Bias– It denotes the number of different voltage levels used in driving the segments, static drives (explained later in this article) only have 2 voltage levels or 2 bias voltage while multiplex drives have multiple voltage levels. For example, 1/3 will have 4 bias voltages.

LCDs utilizes the light modulating properties of liquid crystals which can be observed by using polarizing filters. Polarizing filters are special materials that have their molecules aligned in the same direction. If the light waves passing through polarisers have the same orientation as the filter, then the molecules of lights are absorbed by the filter, hence reducing the intensity of light passing through it, making it visible.

In Layman’s language, when an electric current is applied to the electrodes, i.e. to the segment line and common line, it twists the Liquid Crystals w.r.t to the polarizing filter, obstructing the light in that particular area as shown in the figure below. Hence, that area becomes darker and prominent.

A custom LCD is important for maximizing the efficiency of the display area by adding custom symbols and characters. It also helps in reducing the cost and improving energy efficiency of the product. A higher number of custom symbols and specified placement of numerical and alphanumerical characters make the display more informative and readable for the user. This makes it look better than the plain old boring displays we get in the market. Furthermore, we can specify the viewing angle, contrast, and other specifications which can increase durability or give a better value for money for our intended usage.  A typical Custom Segment display is shown below, we will also show you how to design and fabricate the same further in the article.

The LCD display doesn’t emit any light of its own, therefore it requires an external source of illumination or reflector to be readable in dark environments.

While designing a custom segment LCD display, we have the leverage of choosing a lot of parameters that affect the final product. From the color of the display to the illumination technique and color of illumination as well as the type of input pins. Some important considerations we need to take while designing a custom 7 segment display are - the type of display, i.e. positive or negative, illumination method, driving technique, polarising type, and connection method. All these design criteria are explained below:

Positive and negative displays can be easily distinguished by the colour of the background and characters. Some common differences between the positive and negative displays are:

So, which one should you choose? When the displays are to be used in areas with higher ambient light, we should select positive segment LCD display as it has better visibility than negative segment LCD displays without using a backlight.

As we know that LED displays don’t emit any light, hence to illuminate it and make it visible in a dark environment, we can use different methods of illumination. The most common LCD Illumination methods are compared below:

For displays that need to be used for budget-friendly devices that should be small and rugged, LED lights are preferred for the displays due to the high durability and low cost of operations. For high brightness, CCFL and Incandescent lights can be used.

A polarizer film is the most important component of an LCD display, which makes it possible to display characters by controlling the light. There are 3 types of polarizers that can be used in the LCD display, the properties and difference are given below:

If your products need to be used with a switchable backlight, then trans-reflective reflectors are best to be used for front reflectors. If the device has to be used without backlight, then we can select a reflective polarizer for the back-panel as it gives the best contrast ratio.

Displays can be categorized into two types, passive displays, and active display, passive displays are simpler to construct as they have 2 connections at each segment, the conductors comprise of an Indium Tin Oxide to create an image, whereas the active displays use thin-film transistors (TFT) arranged in a grid. The name is due to its ability to control each pixel individually.

If your displays have fewer segments, then static LCD drive is preferred as it is easier to control and cheaper to construct, and has a better contrast ratio. But let’s say that if the number of segments in the display are more than 30-40 then a multiplex LCD drive should be preferred as it has multiple common pins, hence reducing the total number of pins required to drive the display.

Choosing a connector type!!! For the prototyping phase or if you need to connect your LCD display on a Microcontroller directly, a pin type connector is the best and most economical option you have. If you need to connect your LCD display in a final product with a high volume of production which also requires to be extremely durable, but at the same time should not take up a lot of space, a Flex type LCD Connector will work best for you

LCDs have limited viewing angles and when seen from an angle they lose contrast and are difficult to be observed.  The viewing angle is defined by the angles perpendicular to the center of the display towards its right, left, up, and down which are denoted by the notations 3:00, 9:00, 12:00, and 6:00 respectively. The viewing angle of LCD can be defined as the angle w.r.t. to the bias angle at which the contrast of segments is legible.

To improve the viewing angle in an LCD, a Bias is incorporated in the design which shifts the nominal viewing angle with an offset. Another technique is to increase the Voltage, it affects the bias angle, making the display crisper when viewed from a direction.

For example, the viewing angle of a TN type TFT LCD is 45-65 degrees. Extra-wide polarising film (EWP) can increase the viewing angle by 10 degrees, using an O film polariser can make the viewing angles 75 degrees but these come at a cost of reduced contrast.

Anti-glare filters are bonded with the top polarising filters using adhesive. It improves the viewability by re-directing light waves so they don’t reflect back towards the viewer thus reducing glare. Newer materials are capable of reducing the front glare by up to less than 0.3%.

LCD Control chip or LCD driver chips can be mounted on the flex cable, display, or externally on a PCB. The placement of LCD control chip can affect the cost and size of the display. The 2 most common methods of chip placement are-Chip of Board (COB)and Chip on Glass(COG) which are described below:

COG can be used as it is cheaper and makes the assembly process simpler, but if the dimensions are a constraint, then the COB is also a viable option.

We planned to design an air quality monitoring system for which we needed a custom segment LCD panel for an air quality monitoring device. Our product needs to display the following data: 2.5-micron and 10-micron particulate matter (PM) suspended in the air; the units should be in parts per million (PPM). CO2 in the air in PPM along with total volatile organic compounds present in the air in parts per billion (PPB). To make the product more usable, we included time in 24-hour format, Temperature in ºC, Battery status, loudspeaker status, Bluetooth status, and Wi-Fi status. And for some personal touch, we also added how good the air quality in the room is by using 3 different smileys.

We realized that it was impossible to provide all these data in a generic LCD available in the market, thus decided to build a custom LCD for our project.

A step-by-step flowchart is shown below to walk you through each and every step of selecting components and getting your custom segment LCD manufactured.

We started by listing down our requirements and drew a mock-up of the display on paper. After finalizing the placement of all the segments and icons on the prototype sketch of the display, we then decided which all icons and segments have to be kept on for the whole time and which needs to be driven. Realizing that there are too many segments, characters and icons, hence we selected a multiplex drive with 8 common pins which helped us bring down the total pins from an estimated 180 pins to less than 40 pins.

Since the device was meant to be used inside houses and offices, which are more often than not well lit and protected from environmental conditions, we opted for a positive mode display. For superior contrast ratio and better viewing angle, we chose a Film Super Twisted Nematic Display (FSTN) with a drive condition of 1/8 Duty and bias of 1/4.

Usually, the displays are mounted at a height of 4.5 feet from the ground, thus the viewing direction was selected to be 12"O clock with an operating frequency of 64Hz. We selected a Transmissive polarizer for the front glass and a reflective polarizer for the rear glass so that the natural light can pass through the front panel and the display can achieve the maximum contrast without the need for backlighting and we opted for the pin type connectors as they are easy for prototyping and are suitable for harsh environment with a lot of vibrations and shocks which best suited our purpose.

In the above image of a custom display design, we sent to the manufacturer, the red lines over multiple characters indicate that all these are considered as a single segment. For the sake of simplicity, we added test like T, S, U, B to denote Text, Symbols, Units, and Battery respectively. These characters were followed by numbers to simplify communication between us and the manufacturer. For example, if we needed any particular text or symbol to remain on, we can easily specify that to the manufacturer by using the corresponding text for that segment.

We mailed our requirements to multiple LCD manufacturers, (you will find a lot of LCD manufacturers on the Internet). Most LCD manufacturers have competitive pricing, and reply within a week. A sample requirement sheet is shown above which a customer needs to fill to specify all the details to the manufacturer.

This is a sample Custom Segment LCD quotation we got from one of the manufacturers. As you can see, the cost is based on the quantity. Higher the quantity, lower the cost. Apart from the cost per quantity, there is one more component called tooling fees. Tooling fee is a one-time fee charged by the manufacturer. It is for the technical design, support, and customization of the product. Customization of PCB or tooling of LCD can drive the tooling price higher or lower.

The tooling time and cost depend on how detailed and accurate designs you sent to the manufacturer. They then send the exact dimensions and technical details of the product they will be manufacturing. Once you confirm the design, they manufacture and ship the product which might take 4-8 weeks to arrive depending on the size of the order and mode of transportation selected.

A custom segment LCD can help you personalize your product while also saving the overall cost of your product. The whole process will take you around 2-3 months, which will include the designing phase, prototyping phase, and getting your custom segment LCDs delivered to your doorstep. Higher ordering quantity will reduce the cost per piece of each unit, thus driving down the cost of your final product.

Display screen is everywhere nowadays. Do you still remember the TVs or computer monitors 20 years ago? They were quadrate, huge and heavy. Now let’s look at the flat, thin and light screen in front of you, have you ever wondered why is there such a big difference?

Actually, the monitors 20 year ago were CRT (Cathode Ray Tube) displays, which requires a large space to run the inner component. And now the screen here in your presence is the LCD(Liquid Crystal Display) screen.

As mentioned above, LCD is the abbreviation of Liquid Crystal Display. It’s a new display technology making use of the optical-electrical characteristic of liquid crystal.

Liquid crystal is a state of substance that has both the characteristics of liquid and solid crystal. It don’t emit light itself, but it can let the light pass perfectly in specific direction. Meanwhile, liquid crystal molecule will rotate under the influence of a electric field, and then the light goes through it will rotate too. That said, liquid crystal can be a switch of light, which is the key in display technology.

STN LCD: STN is for Super-twisted Nematic. The liquid crystal in STN LCD rotate more angles than that in TN LCD, and have a different electrical feature, allowing STN LCD to display more information. There are many improved version of STN LCD like DSTN LCD (double layer) and CSTN LCD (color). This LCD is used in many early phones, computers and outdoor devices.

TFT LCD: TFT is for Thin Film Transistor. It’s the latest generation of LCD technology and has been applied in all the displaying scenario including electronic devices, motor cars, industrial machines, etc. When you see the word ‘transistor’, you may realize there’s integrated circuits in TFT LCD. That’s correct and the secret that TFT LCD has the advantage of high resolution and full color display.

In a simple way, we can divide TFT LCD into three parts, from bottom to top they are: light system, circuit system and light and color control system.In manufacturing process, we’ll start from inner light and color control system and then stretch out to whole module.

It’s accustomed to divide TFT LCD manufacturing process into three main part: array, cell and module. The former two steps are about the production of light and color control system, which contains TFT, CF (color filter) and LC (liquid crystal), named a cell. And the last step is the assembly of cell, circuit and light system.

In order to enhance productivity, in this step we’ll do a series of procedure on a large glass, which will be cut into smaller pieces in the following step.

First, let me introduce a crucial material, ITO, to you. ITO, abbreviation of Indium tin oxide, has the characteristic of electrical conductivity and optical transparency, as well as can be easily deposited as a thin film. Thus it’s widely used to create circuit on glass.

Now let’s turn to the production of TFT and CF. Here is a common method called PR (photoresist) method. The whole process of PR method will be demonstrated in TFT production.

Use glue to build a boundary for LC on both glass. And on CF glass, apply one more layer of  conductive adhesive. This enable LC molecule link to the control circuit.

Put the diffuser film and prism film on light source in turn. Together with reflector film, these two films are used to turn the point light from light source into area light and enhance light intensity.

This marks the end of this post. If you find it useful or want to know more about TFT LCD, just leave your comment below or contact us. We’re hearing!

Note: We do not own the images used in this post. Feel free to contact us if they belong to you, and we’ll take them down as quickly as we possibly can.

If you have ever wondered what it took to make your own custom graphic LCD from scratch, this video from [Applied Science] is worth a watch. It’s concise and to the point, while still telling you what you need to know should you be interested in rolling your own. There is also a related video which goes into much more detail about experimenting with LCD technology.

[Applied Science] used microscope slides and parts purchased online to make an LCD that displays a custom graphic when activated. The only step that home experimenters might have trouble following is coating the glass slides with a clear conductive layer, which in the video is done via a process called sputtering to deposit a thin film. You don’t need to do this yourself, though. Pre-coated glass is readily available online. (Search for Indium-Tin Oxide or ‘ITO’ coated glass.)

The LCD consists of a layer of liquid crystal suspended between two layers of conductive glass. An electrical field is used to change the orientation of crystals in the suspension, which modulate the light passing through them. Polarizing filters result in a sharp contrast and therefore a visible image. To show a particular shape, some of the conductive coating is removed from one of the layers in the shape of the desired image. The process [Applied Science] uses to do this is nearly identical to etching a custom PCB.

Parts of LCD technology can be quite hackable. Neither of these videos are brand-new, either. Have any of you taken on the challenge of DIY LCD displays? We’ve seen experiments with electrochromatic glass using old LCD displays, as well as experiments in playing with polarized light to hide secret messages on LCD screens.

To create an LCD, you take two pieces ofpolarized glass. A special polymer that creates microscopic grooves in the surface is rubbed on the side of the glass that does not have the polarizing film on it. The grooves must be in the same direction as the polarizing film. You then add a coating of nematic liquid crystals to one of the filters. The grooves will cause the first layer of molecules to align with the filter"s orientation. Then add the second piece of glass with the polarizing film at a right angle to the first piece. Each successive layer of TN molecules will gradually twist until the uppermost layer is at a 90-degree angle to the bottom, matching the polarized glass filters.

As light strikes the first filter, it is polarized. The molecules in each layer then guide the light they receive to the next layer. As the light passes through the liquid crystal layers, the molecules also change the light"s plane of vibration to match their own angle. When the light reaches the far side of the liquid crystal substance, it vibrates at the same angle as the final layer of molecules. If the final layer is matched up with the second polarized glass filter, then the light will pass through.

If we apply an electric charge to liquid crystal molecules, they untwist. When they straighten out, they change the angle of the light passing through them so that it no longer matches the angle of the top polarizing filter. Consequently, no light can pass through that area of the LCD, which makes that area darker than the surrounding areas.

Building a simple LCD is easier than you think. Your start with the sandwich of glass and liquid crystals described above and add two transparent electrodes to it. For example, imagine that you want to create the simplest possible LCD with just a single rectangular electrode on it. The layers would look like this:

The LCD needed to do this job is very basic. It has a mirror (A) in back, which makes it reflective. Then, we add a piece of glass (B) with a polarizing film on the bottom side, and a common electrode plane (C) made of indium-tin oxide on top. A common electrode plane covers the entire area of the LCD. Above that is the layer of liquid crystal substance (D). Next comes another piece of glass (E) with an electrode in the shape of the rectangle on the bottom and, on top, another polarizing film (F), at a right angle to the first one.

The electrode is hooked up to a power source like a battery. When there is no current, light entering through the front of the LCD will simply hit the mirror and bounce right back out. But when the battery supplies current to the electrodes, the liquid crystals between the common-plane electrode and the electrode shaped like a rectangle untwist and block the light in that region from passing through. That makes the LCD show the rectangle as a black area.

Liquid crystal refers to the intermediate status of a substance between solid (crystal) and liquid. When crystals with a high level of order in molecular sequence are melted, they generally turn liquid, which has fluidity but no such order at all. However, thin bar-shaped organic molecules, when they are melted, keep their order in a molecular direction although they lose it in molecular positions. In the state in which molecules are in a uniform direction, they also have refractive indices, dielectric constants and other physical characteristics similar to those of crystals, depending on their direction, even though they are liquid. This is why they are called liquid crystal. The diagram below shows the structure of 5CB (4-pentyl-4’-Cyanobiphenyl) as an example of liquid crystal molecules.

A liquid crystal display (LCD) has liquid crystal material sandwiched between two sheets of glass. Without any voltage applied between transparent electrodes, liquid crystal molecules are aligned in parallel with the glass surface. When voltage is applied, they change their direction and they turn vertical to the glass surface. They vary in optical characteristics, depending on their orientation. Therefore, the quantity of light transmission can be controlled by combining the motion of liquid crystal molecules and the direction of polarization of two polarizing plates attached to the both outer sides of the glass sheets. LCDs utilize these characteristics to display images.

An LCD consists of many pixels. A pixel consists of three sub-pixels (Red/Green/Blue, RGB). In the case of Full-HD resolution, which is widely used for smartphones, there are more than six million (1,080 x 1,920 x 3 = 6,220,800) sub-pixels. To activate these millions of sub-pixels a TFT is required in each sub-pixel. TFT is an abbreviation for "Thin Film Transistor". A TFT is a kind of semiconductor device. It serves as a control valve to provide an appropriate voltage onto liquid crystals for individual sub-pixels. A TFT LCD has a liquid crystal layer between a glass substrate formed with TFTs and transparent pixel electrodes and another glass substrate with a color filter (RGB) and transparent counter electrodes. In addition, polarizers are placed on the outer side of each glass substrate and a backlight source on the back side. A change in voltage applied to liquid crystals changes the transmittance of the panel including the two polarizing plates, and thus changes the quantity of light that passes from the backlight to the front surface of the display. This principle allows the TFT LCD to produce full-color images.

New Vision Display is a custom LCD display manufacturer serving OEMs across diverse markets. One of the things that sets us apart from other LCD screen manufacturers is the diversity of products and customizations we offer. Our LCD portfolio ranges from low-cost monochrome LCDs to high-resolution, high-brightness color TFT LCDs – and pretty much everything in between. We also have extensive experience integrating LCD screen displays into complete assemblies with touch and cover lens.

Sunlight readable, ultra-low power, bistable (“paper-like”) LCDs. Automotive grade, wide operating/storage temperatures, and wide viewing angles. Low tooling costs.

Among the many advantages of working with NVD as your LCD screen manufacturer is the extensive technical expertise of our engineering team. From concept to product, our sales and technical staff provide expert recommendations and attentive support to ensure the right solution for your project.

In addition, our extensive technology portfolio and manufacturing capabilities enable us to deliver high-qu