Handbook for Sound Engineers

The Fundamentals of Display Technologies 1583

of passing both digital and analog video signals. Some
TVs feature DVI-I inputs for greater hookup flexibility.

44.7.6.1 HDMI (High-Definition Multimedia Interface)

HDMI is the second generation digital interface that
evolved out of the DVI standard.
HDMI is a multipin connection used for passing
standard- and high-definition digital video signals, as
well as multichannel digital audio, through a single
cable. These connections are usually found on newer
HDTV tuners, and a growing number of DVD players,
HDTV-ready televisions, and home theater receivers.
HDMI cable accommodates up to 5 Gbps bandwidth, so
it can simultaneously transfer pure digital video and
audio signals without compression (even HDTV video).
HDMI works especially well with a fixed-pixel
display (like a LCoS, plasma, LCD, or DLP TV), and is
backwardscompatible with most DVI connections.
Signals are encrypted with HDCP (high-bandwidth
digital content protection) to prevent recording.
Although many first generation HDMI-equipped
components only pass two-channel audio signals,
HDMI can carry up to eight discrete audio channels,
making it forward-compatible with 7.1 sound systems.
That means you can pass digital video and multichannel
audio signals between newer HDMI-equipped compo-
nents along a single cable.

44.8 Digital Display Technologies

In the early days of the audiovisual industry, it was nec-
essary to immerse oneself in the tiniest details of tech-
nology and how it operated. In today’s market, it is
necessary to understand the basic function of various
technologies, and more specifically, how the basic func-
tions affect the final design, and the solutions presented
to the client and for the specific project.
We will examine the characteristics and basic func-
tions and operation of the following:

•PDP (plasma).

• DLP (digital light processing).


• LCD (liquid crystal display).


• LCOS (liquid crystal on silicon).


• OLED (organic light emitting diode).


• LED (light emitting diode).

44.8.1 Plasma Display Technology

Of all fixed matrix display technologies, plasma, or
PDP displays most closely replicate the smooth image

from a 35 mm film projector and a CRT. Plasma dis-

plays are emissive in nature, and utilize a similar rare

earth phosphor to a CRT to provide color saturation for

the display, Fig. 44-1.

44.8.1.1 PDP Characteristics

• 3 to 4 inch thick displays (wall or base mount).


• 60 to 500 pounds.


• Panel sizes 37 inch, 40 inch, 42 inch, 43 inch, 46 inch,
  50 inch, 55 inch, 60 inch, 61 inch, 63 inch, 71 inch,
  103 inch, and 150 inch.


• 16:9 aspect ratio panels.


• PDP combines the pixel structure of LCD with the
  color generation of a CRT.


• No radiation or high voltage emissions.


• Fast response time.


• High contrast.


• Deep color saturation.

44.8.1.2 PDP Operates in the Following Manner

• The cells are filled with a xenon and neon gas
  mixture.


• A controlled current is passed through the gas.


• Ultraviolet rays are produced by the current ener-
  gizing the gas, creating a plasma.


• Ultraviolet rays hit the red, green, and blue phosphors
  applied inside the cells.


• Visible light is produced by the ultraviolet rays
  exciting the rare earth phosphors.


• Voltage is applied to one of three terminals on a pixel.
  The voltage discharges through the pixel to a second
  electrode ionizing a rare gas (creating a plasma) in the
  process. The ionization creates UV light, which
  excites an R,G, B phosphor causing it to glow (like a
  CRT). Brightness variation is achieved by controlling
  the number of pulses of light that our eyes integrate to
  produce impression of dim or bright areas.

Figure 44-1. Plasma monitor.

Display electrode

Front glass plate

Barrier rib

Rear glass plate

Data electrode Phosphor

Discharge of

ultraviolet

ray

Discharge of

ultraviolet

ray

Discharge of

ultraviolet

ray 0.1 mm

Light output

Projection layer (MgO)