Touch screens for e-Book readers


As e-ink, and TFT-screen e-reader and other devices can be touch.

In order to become a touch screen, on top of it a special transparent layer around the screen, or a special sensors. Such devices are also referred to as touch panels.

Let's look in more detail, what are the touch screens of electronic books, and what kind of stylus - a special "pencil" to draw on these screens or menus to specify the screens can be used.



Resistive touch panel


Resistive sensor - on top of the screen are two layers with a special coating. The top layer of a flexible, low - hard. On both layers sputtered conductive coating having a specific electrical resistance. The electrodes are arranged in a first layer on the left and right, and in the second - on the top and bottom. When you click any object to point of the screen sets the electrical contact with the bottom of the upper layer, the resistance between the electrodes of the two layers of the screen change, and their values are calculated coordinates of the touch point. E-book management program performs any action: pressing the appropriate place touching the menu item, page flipping, drawing notes in the margins, etc.

The advantages of such sensors: simplicity, low cost, you can click on them with a finger and nail, stylus pen for such a panel - just plastic stick. The facility is fairly accurate determination touch coordinates and, consequently, the ability to accurately draw on screen, thin lines.

The main drawback of such a panel - the need to apply some force to the sensor response. Pressure on the surface of the display may damage it. Another disadvantage include the reduction of contrast in the image caused by nonideal transparency sensory layers.

According to this technology, the sensors are made of e-books SONY PRS-350, PRS-600, PRS-T1, PRS-T2.



The capacitive touch panel


The capacitive sensor consists of a transparent glass or plastic plate coated with a resistive electrically conductive material. On all four sides of the plate are the electrodes.On all four sides of the plate are the electrodes. To each of the electrodes is applied alternating voltage. At the touch of the fingertip sensor to such a leak current, since the human body has a large capacity. Measured current values for each of the four electrodes and it calculates the coordinates of the touch point on the screen.

The advantages of such sensors: simplicity, for the sensor response fairly light touch of your finger.

Disadvantages of capacitive sensors: You can click on them just a finger, a stylus for such a screen - a special "pencil", ending with electrically conductive rubber ball size not smaller than a pea, on such screens is very inconvenient to draw thin lines. There are constant false alarms at a touch of the human body in a pocket thin clothing. An additional layer of coated also reduces the contrast of the screen.

According to this technology, the sensors are made of e-books Pocketbook Touch 622, 623.



Infrared Touch Panel


Infrared sensor consists of a set of LEDs and photodiodes, infrared arranged around the screen. LEDs create a grid of beams above the screen. When you touch any object to such a number of sensor beams cut off, and this event is calculated coordinates of the point of contact.

The advantages of such sensors: simplicity, enough to trigger the sensor light finger touch, no additional layers above the screen, reducing the contrast of the image, the stylus can be any plastic stick with the blunt end of a diameter of 5 millimeters.

Disadvantages of infrared sensors: on such screens is very inconvenient to draw thin lines.

According to this technology, the sensors are made ebook Amazon Kindle Touch Special Offer, Amazon Kindle Paperwhite and the Nook Simple Touch, Nook Simple Touch with GlowLight.

There are other types of touch panels, but in modern e-book readers are not used.





E-ink-reader