chip on glass lcd display quotation

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The Displaytech 162GCOG series is a lineup of 16x2 character chip-on-glass LCD modules. These modules have an 65x27.7 mm outer dimension with 61x15.7 mm viewing area on the display. The 162GCOG 16x2 LCD display series has the controller mounted directly onto the LCD glass. The chip-on-glass (COG) technology allows for a cost-effective system build since the display does not require a PCB. Get a quote directly from Displaytech for the 16x2 COG character LCD display from the 162GCOG series.

Available in character and graphic formats, COG (Chip-On-Glass) LCD Displays are designed without a PCB. The LCD driver/controller is bonded directly to the glass of the display. This allows COG displays to be smaller in size, more cost effective and a highly customizable display solution compared to typical LCD modules with a board.

We offer character LCDs and graphic LCDs as modules or COG (Chip On Glass) displays in a wide array of character and pixel configuration sizes. From yellow/green, red, orange, green, blue, amber, white, and RGB backlight colors to displays without a backlight, we have the perfect LCD for your application.

Not EXACTLY what you need? We specialize in custom and semi-custom display solutions. Contact us about creating something that fits your exact specifications.

Dr Pan: Hello, Greg. COG is the abbreviation for chip on glass. It is a technology, which IC is bonded directly onto ITO glass. COG technology is usually used in small size dot matrix monochrome LCD module and TFT LCD module.

NO.1, it can greatly reduce the size of the LCD module because it doesn’t have PCB and it can be as thin as 2.0mm (maybe thinner). The thinner the more expensive.

NO.3, it is cost effective over COB LCD and can totally replace COB LCD in function, especially in graphic LCD modules, because it reduces the number of IC.

NO.4, for some dot matrix LCD modules, it is not possible to apply COB LCD technology because it is too crowded to place so many points on the view area. COG LCD is an economical and feasible solution because the pitch is smaller .

We have received calls to be a second source LCD display supplier for selected technologies of Densitron LCD Displays. This includes Monochrome Graphic and custom segmented TN, STN, and FSTN static displays. The majority of these monochrome displays are FSTN, but can also be built as a STN.

We offer standard LCD display modules that are an equivalent replacement to Densitron’s character LCD display modules. We also offer design assistance to design and build a custom LCD module and glass that will be an equivalent match to your current Densitron LCD module.

At Focus Display Solutions, when we are asked to quote on a “chip on glass” graphic LCD module, we find that many of the displays require a custom display solution and are not off-the-shelf.

If you find that you need a unique LCD design to match your current display requirements, please feel free to contact us. We offer design assistance with the initial prototype through final production.

In the field of flat panel displays (FPD), packaging technology has significant influence on display performance. The electrical and mechanical interconnect between the liquid crystal displays (LCD) and its driver integrated circuit (IC) is a key issue that needs improvement to achieve finer pitch, easier assembly and greater connection reliability. With the decrease of the pixel size and the increase of pixel count for high-density LCD, the overall trend of the driver IC is packaged closer and closer to the LCD itself, even is onto the backside glass of the LCD. Bonding the driver IC chips directly to the glass substrate of the LCD panel might be a better choice when the pitch becomes less than 70–100 μm (Helge & Liu, 1998). Since the announcement by Citizen back in 1983 of a chip-on-glass (COG) driver assembly process for their LC pocket TV, many different types of COG assembly processes have been developed (Helge & Liu, 1998). In COG technology, the driver ICs are bonded directly to the indium-tin-oxide (ITO) traces on the glass without increasing the size of the panel, except for the finer bump pitch and smaller contact resistance, which can bring a significant reduction in the size of the FPD module. Because LCD is particularly heat sensitive and cannot withstand normal soldering temperatures, conductive adhesives are widely used to connect the driver IC to LCD. Usually, there are two different mechanisms used to cure the conductive adhesives, heat curing for thermosetting adhesives and UV curing for thermoplastic adhesives. Among them, heat curing appears to be most common. Nowadays interconnection using anisotropic conductive film (ACF) is the most major packaging method for production of FPD modules, to provide electrical conduction and mechanical adhesion between the driver ICs and the glass substrate with a high resolution, light weight, thin profile, and low power consumption (Myung & Kyung, 2006). Figure 1 presents a schematic illustration of a typical COG connection process using ACF.

The reliability of COG packaging is an important aspect in the electronics industry. It is found that the reliability is much dependant on the properties of the ACF (Lin & Zhong, 2008). Missing strong metal connection, ACF jointing usually has poor adhesion strength and unstable contact resistance, which are the two most critical reliability issues of ACF applications (Kim & Kim, 2008). High adhesion strength is a critical parameter of fine pitch interconnection that fragile to shocks encountered during assembly, handling and lifetime. During the curing process, voids are generated between the chip, adhesion and glass panel. These voids may affect the adhesion strength of the ACF, resulting in low reliability (Uddin, et al, 2004). Mechanisms to affect the stability of contact resistance include water absorption, electrochemical corrosion and metal oxidation, resulting in ever-increasingly unstable resistance through time, particularly under high temperature and high humidity conditions (Wu & Chau, 2002). These degradation mechanisms interfere with the contact resistance of ACF joints and hence limiting the ultimate electrical and mechanical performance of FPD module, which depends to a large extent on the curing conditions, including curing time, temperature, pressure, etc. Successful bonding involves the selection of proper bonding parameter, during which chemical reactions proceed to completion, in order to develop its strong adhesion strength and stable contact resistance.

During ACF bonding process, heat and pressure are applied concurrently to the component, and the conductive particles between an IC bump and a glass substrate pad change their shape from spheres to ovoid to form the z-direction conduction paths. On the one hand, when heat is applied during bonding, the epoxy matrix of ACF is cured and becomes soft first and then rubbery. This transformation allows the ACF to flow, which in turn allows the conductive particles within to move and distribute themselves evenly throughout the ACF joints. When the curing process is completed, the ACF becomes hardened and the mobility of the conductive particles loses. A reliable electrical interconnect should have sufficient amount of conductive particles captured between the bump and pad, and they do not flow away after cured. The fluidity of the conductive particles during ACF bonding is strongly dependent on the curing temperature and time. Higher curing temperature and shorter time will limit the fluidity of particles and chemical reaction of epoxy, resulting in large and uneven contact resistance due to the less particles captured and their uneven distribution. Furthermore, inadequate chemical reaction will decrease the capability to endure the high hydrothermal impact during operations, which will speed the contact resistance shift (Hwang & Yim, 2008). On the other hand, the deformation amount of the conductive particles, determined by the amount of the pressure applied during the bonding process, has also a great influence on the contact resistance and adhesion strength of the ACF joints. Too much pressure will make the particle a larger deformation degree, meaning a larger recovery rate. When the external pressure is cancelled after cured, a larger residual stress will be present, due to the difference of the expanding fore of the deformed particles and the compressive force of the polymer matrix resin, which will speed the interface breakdown between ACF and IC or ACF and substrate. In fact, too much spread of the particles between adjacent bumps or pads, caused by too large pressure applied, will also increase possibility of short-circuiting. Whereas if the bonding force is too low, the particles may not be able to make contact between the connecting bumps and pads (Masahiro & Katsuaki, 2006). Moreover, in some cases an excessive pressure on bumps can cause glass breakage, so the bonding pressure imposed on the backside of the IC must be controlled precisely. Hence, to have a reliable ACF interconnection in a fine-pitched COG module, the thermo-compression bonding conditions need to be optimized except for the material properties of ACF.

Extensive studies have been done on the ACF bonding in past decades. However, most of them focus on certain bonding process parameter optimization, such as bonding pressure, temperature, time, and its correlations with the reliability of ACF joints subjected to various thermal, mechanical or environmental stresses. In fact, these bonding parameters not only influence the contact resistance of ACF joints but also determine their adhesive strengths greatly. Therefore, the electrical performance and adhesive strengths must both be considered to determine the optimum bonding parameters for reliability of interconnection from a systematic viewpoint of ACF curing reaction mechanism. Usually, the curing reaction of ACF is characterized by the curing degree of epoxy resin, defined as the fraction or extent to which the maximum possible cross links has been produced in a reaction. However, little work has been done to reveal the correlations of adhesion strength and contact resistance of flip chip with the curing degree of ACF matrix (Chung, et al, 2008). In the present work, the effect of different curing degrees on the electrical and mechanical properties of a typical ACF is studied through a systematic joints reliability evaluation method, and the optimum curing degree as well as its corresponding curing conditions for the given ACF is suggested to achieve highly reliable ACF joints, where the performance variations of the adhesion strength and contact resistance are considered simultaneously. The later sections are organized as follows. In section two, the degradation data of the contact resistance of some ACF assemblies, bonded with several curing degrees, is collected during a standard high hydrothermal fatigue test. The resistance distribution of the ACF assemblies for each curing degree is verified and the distribution parameters are estimated respectively. In section three, a reliability analysis method based on the degradation data of contact resistance is adopted, and the reliability index as well as the mean-time-todegradation (MTTD) of ACF joints, as a function of the curing degree, is deduced, through which, the optimization curing degree is suggested. In section four, combining with the mechanism analysis and actual experiments, the curing kinetics model of the given ACF is built. Based on which, the optimum bonding parameters are suggested and are verified by way of actual ACF curing experiments. Finally, section five organizes this work and the value of this work is evaluated.

Liquid crystal display (LCD) is a flat panel display that uses the light modulating properties of liquid crystals. Liquid crystals do not produce light directly, instead using a backlight or reflector to produce images in colour or monochrome.

Easby Electronics are able to offer a wide range of standard LCD products from our key display supplier, Raystar. With character displays ranging in size from 8×2 up to 40×4 and graphic displays with resolutions of 122×32 up to 320×240, we’re able to offer a vast range of products. If there isn’t a standard product that fits your requirement, we are also able to offer a semi-custom or full custom solution to suit your requirements.

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.