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DisponibileSecondo Digital-Photo-Frame-Market.Info, il mercato digitale della struttura della foto può essere diviso largamente in tre generi di telai digitali della foto:
1. Simple function digital photo frames
2. Simple "multimedia" digital photo frames
3. Improved "multimedia" digital photo frames
While digital photo frames in the first category
can just display pictures (in JPEG format),
multimedia digital photo frames can play music
and videos additionally. Some models in the last
category can load pictures over the Internet
from RSS feeds, photo-sharing sites like Ceiva,
Flickr, or Picasa, and even by email. Such
networked models usually support wireless
(802.11) connections. Most digital photo frames
display the photos as a slideshow (usually with
an adjustable time interval). Some digital photo
frames can also play movie clips recorded in a
camera's movie mode, MPG files, or MP3 audio.
A digital photo frame consists of three main parts, the LCD-panel, the PCB and the outside frame. The panel can either be analog or digital and they differ in size. The PCB is the heart of the digital photo frame, as it includes the necessary software. For end users, the outside frame can be an important criterion. This outside frame is usually made of plastic or wood.
Digital Photo Frame Memory Cards and Built-in Memory
Very few digital photo frames have built-in
memory and due the high price of in-built memory
this feature has been relatively expensive and
the memory provided has been small.
Number of Digital Photos on a Memory Card:
| Megapixels | 256mb | 512mb | 1GB | 2GB |
|---|---|---|---|---|
| 2 | 291 | 582 | 1164 | 2328 |
| 3 | 225 | 449 | 898 | 1796 |
| 4 | 136 | 272 | 545 | 1090 |
| 5 | 100 | 200 | 400 | 800 |
| 6 | 84 | 165 | 329 | 658 |
The Best Way to Upload Digital Photos onto a
Digital Photo Frame
With a digital photo frame that has a USB port
it is possible to upload photos directly onto
the memory chip in the frame. This feature is
very useful but is not imperative if one has a
USB memory card adaptor.
Digital Photo Frame LCD Technology
Today's flat-panel desktop monitors almost
exclusively use liquid crystal display (LCD)-based
panels. Almost all LCD monitors are based on
active-matrix thin-film transistors (TFTs) to
provide bright, sharp displays. Another type of
LCD display called passive-matrix, used widely
in early laptop computers, never made it into
desktop displays due to the image ghosting,
limited viewing angle and streaking associated
with this type of LCD. TCT LCDs are made of
several layers that are arranged in the
following order: polarising filter, sheet of
glass, electrode, alignment layer, liquid
crystals, alignment layer, electrode, sheet of
glass and polarising filter. The cross-section
of the TFT LCD panel looks like a multi-layer
sandwich. The outermost layers on either side
are clear glass substrates. Between the
substrates are the thin film transistor, colour
filter panel, which provides the necessary red,
blue and green primary colours and the liquid
crystal layer. Completing the LCD is a
fluorescent back light that illuminates the
screen from behind.
In traditional active-matrix TFT displays and under normal conditions, when there is no electrical charge, the liquid crystals are in an amorphous state. In this state, no image is visible. By subjecting the liquid crystal layer to varying amounts of electrical charges, the liquid crystal layer will allow different amounts of light to pass through as they orient themselves according to the control centre for the liquid crystals. In basic terms, each pixel can be thought of as a vertical blind. When a charge is applied, the liquid crystals of the pixel untwist to block the light from the backlight to not allow light to come through. When an electrical charge is not applied, the blinds open up, allowing light from the backlight to pass and thus illuminate either the red green or blue crystals.
The red, green and blue liquid crystal "chambers" make up one pixel (picture element). By subjecting the red, green and blue chambers to varying degrees of electrical charges, different colours can be achieved. An entire TFT screen is made up of a grid of pixels, with each pixel having a transistor for each colour turning it on or off. This is where you get your resolution. Thus, for an LCD to provide a screen resolution of 1024 x 768 pixel (XGA), it must have that exact number of pixels.
