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Display News 2021

The right touch for every purpose

Which is better? Resistive or capacitive touch panels? The two input techniques not only differ in the way they work; they also have different strengths and weaknesses.

Touch-sensitive displays are an essential part of modern measurement and control equipment. Unlike mechanical switches and controllers, they make it easy to create flexible applications and interactive user guidance. Mainly resistive and capacitive touch surfaces are used. To recognise an input, they make use of different electrical effects.

Pressure creates resistance
The resistive touch panel uses the change in resistance, which is measurable when two conductive layers touch, to determine position. It essentially consists of a flexible, transparent plastic film and a rigid glass or plastic support underneath. Both elements are coated on an electrically conductive basis with indium tin oxide (ITO) on their inner sides. Very small rubber buffers, the spacers, keep them at a distance and isolate them from each other. If the flexible foil is pressed in at one point, a voltage divider is created by the contact, with the help of which the position can be determined by two measurements. First, a defined DC voltage is applied to the upper foil and the voltage at the point of contact is measured via the lower disc. This is linearly proportional to the distance of the pressure point from the edge. The voltage is then applied to the lower support and measured at the top. This clearly determines the position.
The resistive touch panel responds quickly and precisely. It can be operated reliably even with thick gloves, prostheses and any type of pen. Therefore, it is very flexible and secure in its response. However, its elastic surface is sensitive to scratches and not entirely free of wear. Inputs with multiple fingers at the same time or gesture control are only possible on it to a limited extent. The two-layer structure impairs the readability of the underlying display in direct sunlight. With a transparency of about 80%, it is slightly darker than a capacitive panel. Because it reacts to any kind of pressure, contact with other objects can also trigger unwanted actions, for example during transport.
Among other things, touch panels are the preferred choice for outdoor devices that require reliable operation under the most difficult conditions.

Sensitive field influence
The capacitive touch panel (PCAP) responds to a mere touch without the need for mechanical pressure. It consists mainly of a rigid, transparent disc to which two mutually insulated grids with conductive tracks made of transparent indium tin oxide (ITO) are attached. This creates tiny capacitors at the crossing points whose capacities are permanently measured. If alternating current is applied to this system, an electric field builds up on the surface. When a finger approaches the panel, it changes the field at that point. The abbreviation "PCAP" stands for "Projected Capacitive Touch" because the sensitive layer is located on the underside of the cover glass, i.e. the capacity of the finger is projected onto its own capacity.
The surface of a capacitive touch panel is usually made of glass and is therefore scratch-resistant. The position of several fingers can be detected simultaneously, enabling multi-touch actions and gesture control. With a transparency of 87%, it is slightly more translucent than a resistive touch panel.
However, the response behaviour of capacitive touch panels is not quite as reliable as that of resistive surfaces. Since they react to the electrical conductivity of the human body, they can at best still be operated with thin gloves or conductive special pens. Even dry skin or prostheses cause difficulties here. Displays with this type of interface are therefore not readily accessible. Water drops also impair the function to the point of inoperability. Nevertheless, almost all smartphones and tablet computers today are equipped with capacitive surfaces.

Many possible combinations
With ELECTRONIC ASSEMBLY's intelligent display series eDIP and uniTFT, you do not have to worry about the technical details. Both model series support the respective touch panel technology both on the hardware and software side. Thanks to the already integrated functions, buttons, controllers or switches can be easily defined and corresponding actions can be stored. This means that nothing stands in the way of the rapid development of prototypes and series. Especially as Electronic Assembly intensively supports its customers in their projects with advice and assistance as well as powerful development tools.

More information here.

The smallest colour display in the world

Smallest TFT / IPS display

With a diagonal of just 0.96 inches, the ELECTRONIC ASSEMBLY EA TFT009-81AINN LCD colour display is perfect for installation in handheld devices of all types. The high brightness overhead and the wide viewing angle stability of the IPS panel guarantee excellent readability, even under poor light conditions.

The new EA TFT009-81AINN LCD colour display from ELECTRONIC ASSEMBLY is not even the size of a thumb. Despite this, the roughly one by three centimetre area (0.96 inch diagonal) holds 80 by 160 pixels. It can be used to realise high-resolution graphic displays in colour or black and white. The powerful, white LED backlight gives the display a brightness of up to 500 cd/m². As a result, it has great readability even in direct sunlight or under dazzling operating lights. Since it is an IPS panel with all-angle-colour technology, the colours and contrast remain stable even at very oblique viewing angles.

It is controlled via the integrated ST7735S graphics controller. Its SPI interface manages with four or three wires. The mini display is therefore particularly suitable for applications in which every connector pin saved counts. This graphics panel will soon also be available with a capacitive touch surface under the designation of EA TFT009-81AITC. It will then also have an I²C interface which significantly streamlines direct reading of the coordinates which are touched.

The display requires a 3.3 V power supply and works reliably in a temperature range of between -20 °C and +70 °C. It can be operated both upright and in landscape format. Thanks to its small dimensions, it is particularly suitable for use as a display in wearables, as well as in measuring probes, battery drill screws and handheld electronic devices of all types. Combined with the touch surface, it becomes an informative switch element. ELECTRONIC ASSEMBLY guarantees rapid delivery off the shelf as well as long-term availability.

Ideal for extremely compact handhelds and wearables. More information the Datasheet

Buy directly in our webshop for displays.

TFT Displays with OLED viewing angle

IPS Displays: strong in contrast even in direct sunlight

ELECTRONIC ASSEMBLYs brilliant TFT displays offer all-round viewing angles comparable to OLED panels. Thanks to their extraordinary brightness, they are perfectly readable even in extremely bright environments.
Conventional TFT displays have one weak point: the more you look at the display at a slant, the weaker the contrast becomes. At a certain angle it can even tip over completely (gray scale inversion effect). Self-luminous OLED panels don’t have this effect, but they are limited in maximum brightness and life time. The IPS color displays from ELECTRONIC ASSEMBLY combine the best of both techniques. Thanks to their AACS (All Angle Color Stability) technology, contrast and colors of these graphic displays remain virtually unchanged even at extreme viewing angles. With a brightness of up to 1,000 cd/m², these displays are also clearly readable in direct sunlight. Whether in the operating room or the outdoor measuring station, these displays are in demand wherever one glance has to be enough.
ELECTRONIC ASSEMBLY offers the compact TFT displays in staggered sizes from 2" to 7". Even the smallest version already has a fine resolution of 240 x 320 pixels. All displays can be ordered with capacitive multi-touch surface.

More information on our IPS Displays.

Mini OLED for ZIFF

Mini OLED 96x16 dots with FPC cable for ZIFF connector

The smallest OLED display with practical FFC cable measures just 29.1 x 9.2 mm. Brilliant 96x16 pixels offer enough space for 2 lines of text or large digits including icons. The display runs smoothly between -40 and 80°C, SPI and I²C bus are standard.

Ideal for extremely compact handhelds and wearables.

 

 

 

 

 

 

More information on our OLED Displays.

Here's the Datasheet

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