Custom glass

In cost sensitive applications such as utility meters (which require segments only or simple alphanumeric text), LCD glass only is the best solution, with the LCD driven directly from the host microprocessor/controller IC. For a small tooling charge, we can fully customize this LCD glass (size, image, temperature range etc.) to provide you with 100% satisfaction.

		Process for glass:

   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 prototypes 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 LCDs are manufactured to all approved specifications and all previously agreed specifications, e.g. test and QC specs.

		Criteria for custom glass quotation:

	To ensure that our custom glass 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 glass criteria are:
		LCD technology
		Overall Dimensions
		LCD image
		Polarisers
		Display mode
		Operating environment
		Drive method
		Connection method

    LCD Technology

    We need to know which of the following technologies best meets your custom glass requirements

		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.

    Overall Dimensions

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

    LCD Image

We need to know what type of data imaging you require on the display, e.g. 7 segment digits (6mm) plus icons, alphanumeric dot matrix (5 x 7 dots per character) or Graphics etc.

    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)

     Operating Environment

PWe need to know the precise details of the operating environment in which the display will be used.

     Drive Method

We need to know the multiplex rate (also known as the duty.) For example: 1/4, 1/8 duty or 4 mux, 64 mux.

     Connection Method

    Connection methods are available in three options:

		Elastomeric Connection: Provides a low-cost, solderless, high density connection. In order to achieve the necessary compression (typically 10 to 15%), the glass will also require a bezel. Elastomeric is also known as Zebra strip.
		Pin Connections: The pins are epoxy-bonded to the edge of the glass. Typical pitch is 2.54mm, but 1.80mm and 2.0mm also available.
		Heatseal Connection (HSC): A foil of alternating conductive and insulating material is bonded by heat and pressure to the LCD to provide a highly reliable connection. The other end can be either bonded to a PCB or inserted into a suitable ZIF connector.

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