Dot Arrays: Pixels can be made in almost any size and dot count.  Examples include character displays that use a series of 5x7 dot arrays in order to create a string of alpha-numerical characters, or the larger 320 x 240 pixels (QVGA) graphic arrays where complex images can be displayed in the LCD.

Transmissive: This type of viewing mode requires a back-lighting system to be incorporated behind the LCD. During day-time viewing in direct bright sunlight conditions, the display may be difficult to read due to the back-light having difficulties overpowering the high ambient lighting. However, during night-time viewing the brightness will be very high and this type of display is therefore appropriate for indoor applications.

Backlighting for transmissive LCD’s

When developing a transmissive type LCD, a backlighting system may be required in order to illuminate the display from behind and there are several options available. The considerations for a backlighting system are the lighting intensity, lifetime and consumed power and there are several different design possibilities available.

LED:  The use of Light Emitting Diodes (LED’s) is often recommended due to the variety of different colours available, high intensity, long life (>100K hrs), wide operating temperature range and low voltage requirements. The downside is the relatively high power consumption when large arrays of LED’s are used in order to illuminate large sized LCD’s as well as the lower uniformity of the lighting system.

EL Panel:  Electro-luminescent Panels (EL) consume extremely low power, but require high voltage operation (eg. 120VAC @ 400Hz) and possess a relatively short lifetime (half-intensity lifetime <4K hrs) together with a medium operating temperature range.

Cold Cathode Florescent Lamp:  The use of cold cathode florescent lamps provides for high illumination intensity relative to the power consumed and is recommended when considering large sized LCD’s. The downside is the relatively short lifetime (<20K hrs), sensitivity to large vibration which further reduces the lifetime of the tube, limited operating temperature range and the relatively high operating voltage required (eg. >300VAC @ 30-80KHz).

Viewing angle for LCD

The viewing angle of an LCD is defined by the angles above, below, left & right of the perpendicular direction to the centre of the display. These angles are defined as follows:

i)  06:00 o’clock viewing angle has optimum contrast when the LCD is viewed from below the perpendicular viewing plane (standard configuration).

ii)  12:00 o’clock viewing angle has optimum contrast when the LCD is viewed from above the perpendicular viewing plane.

iii)  09:00 o’clock & 03:00 o’clock viewing angles have optimum contrasts when the LCD is viewed from the left & right sides respectively of the perpendicular viewing plane (non-standard configuration).

Please note that viewing angle consideration is less important for a direct-driven LCD since the angular properties of the display are relatively homogeneous. However, as a general rule the higher the multiplex rate, the more important is the consideration of viewing angle. Furthermore, should the LCD be viewed by an observer wearing polarised sun-glasses, it is necessary to specify this in order to ensure that the LCD will not look "blank" when viewed using sun-glasses.

Required temperature range for LCD
 
The required operating & storage temperature ranges for an LCD are important considerations and operation outside of these limits may result in either the display not being readable (above operational temperature range) or the display becoming permanently damaged (outside of storage temperature range).

The combination of the LCD fluid, polarisers, operational voltage and multiplex rate determine the operating temperature range for the LCD and typical values are as follows:

TN (direct driven): Standard operating temperature range -10 to +65°C

STN & F-STN: Standard operating temperature range: 0 to +50°C

Cholesteric (Ch-LCD) (direct driven): Standard operating temperature range -50 to +70°C

Driving Method for LCD’s

The Driving Method controls how each segment, icon or pixel of the LCD is connected to the electronic driving circuitry and there are two possible methods available:

Static Drive (direct driving): The static or direct driving method requires an individual electrical connection line for each display segment and there is only one common GND connection for all segments. The total number of electrical connections required to the LCD is therefore the same as the total number of segments or icons present in the display. The static drive configuration is therefore suitable for LCD’s where there are only a limited number of segments or icons to be displayed (eg. total number of segments is less than approximately 150pcs). This driving method produces the best display contrast and viewing properties together with the widest operating temperature range, but it requires a higher number of electrical interconnections relative to the multiplexed driving method hereinunder.

Multiplexed Drive: The multiplexed driving method requires that each control line selects several segments or icons simultaneously and the final selection is controlled by selecting the required GND back-plane that also simultaneously connects to several segments. This driving method requires less interconnections than that for the static driving configuration and therefore enables a higher number of segments or icons to be displayed within the LCD. However, the use of the multiplexed driving method results in reduced contrast and viewing properties together with a reduced temperature operating range.

Driving electronics for LCD’s

Please note that LC-Tec Displays AB supplies LCD products in the form of the LCD-glass plus electrical contacting only but without controlling electronics. The reason for this is that the LCD component is usually incorporated into a larger product system and it is invariably more efficient to incorporate the driving electronics for the LCD together with the electronics for the complete product system as a whole.

From the customer’s point of view, the main reasons for procuring the LCD glass part only are to reduce costs and provide design flexibility. The total cost of the electrical components necessary to build the drive circuitry is invariably much less than the cost of a pre-built complete display module and as long as there is available space on your existing Printed Circuit Board (PCB), it will not be necessary to incorporate an additional PCB on which to mount the LCD component.

Pricing & ordering

LC-Tec Displays AB provides a fixed commercial quotation for the manufacturing & supplying of custom LCD product including NRE manufacturing tooling costs so that the total costs are established & identified prior to the placing of an order.

By using our own manufacturing facilities both in Sweden & China, manufacturing costs are kept to a minimum in order to be able to offer both competitive pricing as well as a fast turnaround time for the manufacturing of new custom LCD product.

Please click here to download the "Custom LCD Request Form". Please return this form to LC-Tec Displays AB in order to receive a commercial quotation and detailed design specifications for your LCD component.

Competitive Pricing on Existing LCD Product

Please fill in the "Custom LCD Request Form" available for download here or send a copy of your current specifications for the custom LCD and we will endeavour to supply to you a high quality product with competitive pricing.

You may also fax or Email a drawing or sketch of your required LCD in order that we can rapidly analyse your requirements. Our engineers will offer recommendations in order to reduce common errors, costing and lead-times and also do an extensive review of the manufacturing feasibility of your LCD design in order to make sure it is compatible with your requirements and overall goals. Please therefore contact LC-Tec Displays AB for a free design consultation with one of our design specialists.