Custom modules overview

An LCD module is the most cost effective solution for applications requiring dot matrix alphanumeric or graphics LCD's. Our extensive range of standard LCD modules provide all the necessary LCD drivers, mounting and connection, as well as backlighting if required.

We also specialise in the design and development of semi custom and custom LCD modules.

Semi-custom LCD modules
We can modify the PCB and/or interface of our standard modules to provide you with a semi custom module to meet your requirements. In order to reduce your final assembly cost, we can also include additional components such as LED indicator lamps, switches, keypad traces and cable assemblies. Tooling charges are very low, because our semi-custom LCD modules use the LCD panel, bezel and backlight from existing standard modules.

Custom LCD modules
The main components of our custom LCD modules - LCD glass, bezel, PCB and backlight - are custom parts, while the electronic and electrical components, e.g. the LCD controller and driver IC's, are usually standard components specified by either Anders or the customer. If required, we can also integrate custom micro-controllers or ASIC's in our custom LCD modules. Contrary to prevailing opinion, custom LCD modules do not require high tooling charges, but have a similar charge to any other custom assembly tooling charge.

		The customization process:

The custom LCD module development process involves the following steps:

   Feasibility stage

	Technical Feasibility: We evaluate your specifications to determine whether or not the LCD can be manufactured. We can use either a basic outline or full specification. This stage is carried out by the UK engineering team
	QA feasibility: We evaluate your QC requirements and specifications to determine whether or not we can satisfy them. This may also include the customer test specification.
	Commercial Feasibility: We evaluate your specifications and requirements to determine whether the LCD can be manufactured within your budget. This stage is carried out by the UK and Far East offices. At this stage we also determine and agree with you the minimum order quantities and minimum production quantities.

    Design stage

Upon receipt of the tooling order we proceed with the design. Based on your specifications and results of the feasibility study, our engineering departments in the Far East will produce counter drawings and specifications. These drawing are checked and approved by our UK engineering team before being sent to you for approval. Counter drawings take from 1 to 3 weeks according to the complexity.

   Prototype stage

	Once you formally approve the counter drawings, we proceed with the prototypes.
	The prototypes take from 4 to 12 weeks according to the complexity of the design and the availability of the materials.
	The prototypes are manufactured in the Far Eastern LCD factories. Before being sent to you, the protitypes are tested against the approved specification by both the UK engineering team and the Far Eastern engineering department.
	At this stage we also review the current lead times and materials to determine whether or not the results of the feasibility study are still applicable.

   Production stage

	Production can proceed once you have formally approved the prototypes.
	The LCD's are manufactured to all approved specifications and all previously agreed specifications, e.g. test and QC specs.

		Criteria for custom modules quotation:

To ensure that our custom modules solution is the perfect match for your specific needs, and to ensure that we provide you with an accurate initial quotation, please make sure that you supply us with specific information about your requirements, as per the criteria below. If you need clarification of any kind, please consult our sales support team. It is their job to help you make the right decisions. The custom modules criteria are:

	LCD technology
	Overall Dimensions
	Polarisers
	Display modes
	Module assembly options

   LCD Technology

Twisted Nematic (TN) TN is the simplest LCD technology. Common applications include calculators, heating controllers and utility meters. The LC twist angle is 90°, making this technology ideal for simple "digit" or "icon" images, with little or no need for multiplexing. Suitable for mux. rates of 1:1 to 4:1. Typical temperature range: -30°C to +85°C.

First Minima TN (FMTN) When the transmission of monochromatic light is measured through a TN cell between parallel polarisers, zero transmission occurs at several points, 1st minima, 2nd minima, 3rd minima. In a positive mode display, maximum contrast is achieved by selecting the 1st minima point, hence the name First Minima TN displays. Temperature range: -30°C to +85°C.

Enhanced TN (ETN) Designed for negative mode displays, using the higher minima points with the higher cell gap to produce a 'blacker' background. This technology originated in the automotive industry where bright backlighting makes a high "black value" - important for avoiding bleed through of light in non selected areas.

Super Twisted Nematic (STN) As the multiplex rate of a display increases, the voltage between the non selected and selected voltages (Von/Voff) decreases. For drive schemes from static through to 1/4 mux, this voltage difference is large enough in a TN cell to maintain an acceptable contrast level and avoid cross talk. However, multiplex drive schemes from 1/8 to 1/480 mux require the steeper electro optical characteristics of STN, which has a slightly more limited temperature range (-30 to +80°C) than TN due to its higher complexity.

Film Super Twisted Nematic (FSTN) By adding a compensation foil on top of the LCD to neutralise the natural colouring of yellow-green/purple in STN displays - a process which gives rise to FSTN (Film STN) - customers who prefer neutral black and white can achieve backlighting to whatever colour they want.

Automotive Super Twisted Nematic (ASTN) Similar to FSTN, except that it uses a complex compensation foil which gives the display better overall performance throughout the temperature range, and actually improves as temperatures rise. While FSTN performance drops significantly (i.e. the background gets darker) above 50°C, ASTN performance is still good and remains stable right up to 80°C and above (complying with automotive standards).

ESTN (Enhanced STN) and ISTN (Improved STN) These displays have been developed to further increase the performance of displays in terms of contrast by adding dyes to the fluid and using super-efficient polarisers to allow better use of the available light. ESTN and ISTN offer high reliability and low performance variation (colour, viewing angle) with temperature. A wide temperature range is also feasible.

Double Super Twisted Nematic (DSTN) DSTN displays consist of two LC cells; one active and one passive bonded together. The direction of LC twist of one cell has an equivalent opposite LC twist of the other. This results in a very black background with virtually no bleed through of backlight when used in negative mode. It also offers a very wide viewing angle from all directions when compared to FSTN. The operating temperature range can be -40 to +85 deg C, which make this type of display fully compatible with the requirements of the automotive industry.

   Overall Dimensions

We need to receive the exact measurements of your custom modules requirements.

   Backlighting

A choice of backlighing options is available for your custom LCD module, according to the ambient lighting conditions of your application:

	LED Backlights: These are the most popular for alphanumeric and small graphic custom LCD modules, requiring a single low DC voltage supply and providing long lifetime and high brightness over a wide temperature range (-30 to +85 deg C). LED backlights are available in the following colours: Yellow/Green, Pure Green, Red, Orange/Amber, Blue, White. A bi-colour option is also available.
	Array Type Light Box: Used mainly in applications where space and power consumption are not an issue. Bare LED dies are evenly spaced and bonded onto the surface of a PCB. To prevent any visible "hotspots" of light emanating directly from the LEDs, a translucent film is fitted on top of this PCB. The overall lit area of the LCD display and the required brightness will dictate the quantity and electrical configuration of the LEDs.
	Edgelit Type Backlights: Because this requires less LEDs and a lower profile, Edgelit is ideal for applications where a lack of space and relative low power consumption are required. Bare LED dies are evenly spaced and bonded onto the surface of a slim (height typically 3mm) PCB which is slotted into the side of an injection moulded "lightguide" which diffuses the light through the material. By adding a translucent film and/or a white silkscreen printed dotted pattern, you will achieve a very homogenous backlight similar to Array Type Backlighting.
	Cold-Cathode Fluorescent Lamp (CCFL) Backlights: These provide a high intensity uniform white backlight, and are commonly used on medium and high resolution graphics modules.
	EL Backlights: Only used where there is a requirement for a thin module profile and low power consumption. EL backlights have a limited operating lifetime and require a DC - AC inverter.

   Polarisers

LCDs are constructed with three types of polariser films: Transmissive, Reflective or Transflective. Front surface polarisers are always transmissive. Rear surface polarisers can be any of the three.

	Transmissive polarisers are used in low ambient applications that require backlighting, and allow maximum transmission of the backlight brightness. The image is not viewable when the backlight is not switched on.
	Reflective rear polarisers are used in applications with no backlight, either because of insufficient backlight power or because of high ambient light.
	Transflective rear polarisers combine transmissive and reflective polarisers, which means that the image can be viewed in high or low ambient light when the backlight is switched on.

   Display Modes

   Display modes are available in two options:

	Positive mode (dark characters on light background)
	Negative mode (light characters on dark background)

   Module Assembly Options

The assembly option for your custom LCD module will depend on the LCD controller and driver I.C's, their associated mounting package, and the mechanical constraints of your application. The choice I.C's can be specified by you, or we can provide what we regard as the most suitable for your application.

	Quad Flat Pack (QFP): The IC's are soldered on to the rear surface of a rigid PCB. The LCD glass is bezel mounted to the front surface, and connected to the PCB using the Elastomeric or Heatseal connection method.
	Chip On Board (COB): The IC's in their bare die form are bonded directly to the rear surface of a rigid PCB. The LCD glass is bezel mounted to the front surface, and connected to the PCB using the Elastomeric or Heatseal connection method.
	Tape Automated Bonding (TAB): One end of the Tape Carrier Package (TCP) containing the IC's is bonded to the LCD. The other end is either bonded directly to the customer's PCB or to a rigid PCB. If an additional rigid PCB is required, the LCD is bezel mounted to it.
	Chip On Glass (COG): The IC's in their bare die or with a gold bump are bonded directly to the LCD glass, and connected to the IC and LCD glass via an FPC tail or gold loaded elastomer. Backlighting of the COG module is achieved by attaching a plastic bezel with integrated LED backlight directly to the LCD glass, or by soldering the COG FPC tail to a rigid PCB and bezel mounting the LCD glass and backlight to a rigid PCB.
	Chip On Film (COF): The IC's in their bare die form as well as other discrete components are bonded to a flex. One end of which is bonded to the LCD glass, and the other is either inserted in to a suitable ZIF connector or bonded to a PCB.

​