LaserDisc (LD) is a home video format and the first
commercial optical disc storage medium initially licensed, sold, and marketed
as MCA DiscoVision (also known as simply "DiscoVision") in North
America in 1978.
Although the format was capable of offering higher-quality
video and audio than its consumer rivals, the VHS and Betamax videocassette
systems, LaserDisc never managed to gain widespread use in North America,
largely owing to high costs for the players and the video titles themselves. It
also remained a largely obscure format in Europe and Australia. However, it was
much more popular in Japan and in the more affluent regions of South East Asia,
such as Hong Kong, Malaysia and Singapore, being the prevalent rental video
medium in Hong Kong during the 1990s.
The technologies and concepts behind LaserDisc are the
foundation for later optical disc formats, including Compact Disc, DVD, and
Blu-ray Disc.
The earliest players employed gas helium-neon laser tubes to
read discs and had a red-orange light with a wavelength of 628 nm, while later
solid-state players used infrared semiconductor laser diodes with a wavelength
of 780 nm.
In March 1984, Pioneer introduced the first consumer player
with a solid-state laser, the LD-700. It was also the first LD player to load
from the front and not the top. One year earlier Hitachi introduced an
expensive industrial player with a laser diode, but the player, which had poor
picture quality due to an inadequate drop-out compensator, was made only in
limited quantities. After Pioneer released the LD-700, gas lasers were no
longer used in consumer players, despite their advantages, although Philips
continued to use gas lasers in their industrial units until 1985.
Most LaserDisc players required the user to manually turn
the disc over to play the other side. A number of players (all diode laser
based) were made that were capable of playing both sides of the disc
automatically.
While Pioneer produced some multi-disc models that held more
than 50 LaserDiscs, one company offered, for a short time in 1984, a
"LaserStack" unit that required the user to physically remove the
player lid for installation and attached to the top of the Pioneer LD-600,
LD-1100 or the Sylvania/Magnavox clones. LaserStack held up to 10 discs and
could automatically load or remove them from the player or change sides in
around 15 seconds.
Only one consumer player, the LD-W1 (it was also released
industrially too), was made that could hold more than a single disc; the W1 held
two discs and could automatically change discs and sides by rotating the entire
mechanism, including both the laser and turntable.
The first mass-produced, industrial LaserDisc player was the
MCA DiscoVision PR-7820, later rebranded the Pioneer PR7820. In North America,
this unit was used in many General Motors dealerships as a source of training
videos and presentation of GM's new line of cars and trucks in the late 1970s
and early 1980s.
Most players made after the mid-1980s were capable of also
playing Compact Discs. These players included a 4.7 in (12 cm) indentation in
the loading tray, where the CD would be placed for play. At least two Pioneer
models (the CLD-M301 and the CLD-M90) also operated as a CD changer, with
several 4.7 in indentations around the circumference of the main tray.
The Pioneer DVL-9, introduced in 1996, was both Pioneer's
first consumer DVD player and the first combination DVD/LD player.
The first high-definition video player was the Pioneer
HLD-X0. A later model, the HLD-X9, featured a superior comb filter, and laser
diodes on both sides of the disc.
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