Electric lamp and discharge devices: systems – Plural load device systems
Reexamination Certificate
2000-03-14
2003-09-16
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Plural load device systems
C315S112000, C315S316000
Reexamination Certificate
active
06621239
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to theatre lighting, and more particularly to controlling the temperature of lighting devices such as multi-parameter lights that include both optical and electromechanical components.
2. Description of Related Art
Theatre lighting devices are useful for many dramatic and entertainment purposes such as, for example, Broadway shows, television programs, rock concerts, restaurants, nightclubs, theme parks, the architectural lighting of restaurants and buildings, and other events. A multi-parameter light is a theatre lighting device that includes a light source and one or more effects known as “parameters” that are controllable typically from a remotely located console. For example, U.S. Pat. No. 4,392,187 issued Jul. 5, 1983 to Bohnhorst and entitled “Computer controlled lighting system having automatically variable position, color, intensity and beam divergence” describes multi-parameter lights and a central control system. Multi-parameter lights typically offer several variable parameters such as pan, tilt, color, pattern, iris and focus.
A multi-parameter light typically employs a light source such as a high intensity lamp as well as motors and other motion components which provide the automation to the parameters. These components are typically mounted inside of a lamp housing and generate large amounts of heat inside of the lamp housing, so that cooling by convection or forced air is required. The high intensity lamp generates the greatest amount of heat. However, motors used to automate the parameters also generate significant amounts of heat. Heat generation by the motors is a function of the number of motors within a lamp housing as well as the usage of the motors. Heat generation increases with increasing numbers of motors and with repetitive use in a high duty cycle. Various optical components such as filters, projection patterns, shutters, and an iris diaphragm are used within the lamp housing to collimate the light and focus patterns to be projected. These optical components are selectively moved in and out of the light path or controllably varied in the light path by motors to vary the attributes of the projected light, and generate varying amounts of heat as they interact with the light beam by reflection or absorption.
Many variables affect the internal temperature of the lamp housing of a multi-parameter light. For example, lamps provided by different manufactures may have differences in lumens per watt, or may have a spectral distributions that create more energy in the infrared spectrum thus further raising the internal temperature of the multi-parameter light. The optical components in the lamp housing that are used to vary the parameters lie in the path of the projected light. These components may reflect or absorb light. Light collimated or condensed by the optical components may be reflected back into the lamp housing, the components of the lamp housing, or the lamp itself, causing a rise in temperature of the lamp housing and its components. Light may also be absorbed by the optical components when placed in the path of the projected light. As these components absorb the condensed or collimated light, they generate heat and raise the temperature within the lamp housing. The ambient air temperature to which the instrument is exposed may also raise the internal temperature of the lamp housing from 25 to 40 Celsius. The position of the multi-parameter lamp housing also is a factor in the operating temperature, since the position may allow heat to rise in certain areas of the lamp housing. The motors within the lamp housing when used repetitively for shows or events that often repeat the change of a parameter may raise the temperature inside of the lamp housing and its components by 5 to 15 degrees Celsius.
Because of the presence of such substantial amounts of heat, some multi-parameter lights are constructed of various high temperature materials. For example, the insulation of the wiring to the lamp may be silicon or Teflon. The lamp housing of the multi-parameter light may be constructed of a high temperature polymer, which additionally helps to reduce the weight of the light and is often molded into a pleasing design shape. However, as the heat capacity of even these materials is not infinite, various cooling techniques are used. The most common cooling techniques are convection and forced air cooling. An example of a convection cooled multi-parameter light is the model Studio Color® 575 wash fixture, available from High End Systems, Inc. of Austin, Tex., URL www.highend.com. In this type of multi-parameter light, the convection cooled lamp housing contains the lamp, motors, optics and mechanical components, and is rotatably attached to a yoke that facilitates pan and tilt. The yoke is rotatably attached to a base, which contains the power supplies and control and communications electronics. See also U.S. Pat. No. 5,515,254, issued May 7, 1996 to Smith et al. and entitled “Automated color mixing wash luminaire,” and U.S. Pat. No. 5,367,444, issued Nov. 22, 1994 to Bohnhorst et al. and entitled “Thermal management techniques for lighting instruments.” An example of a forced air cooled multi-parameter light is the model Cyberlight® automated luminaire, available from High End Systems, Inc. of Austin, Tex., URL www.highend.com. In this type of multi-parameter light, the forced-air cooled lamp housing is stationary and contains all of the necessary operating components, including a positionable reflector to achieve the pan and tilt parameters.
Neither convection cooling nor forced air cooling is entirely satisfactory. Convection cooling is quiet but does not dissipate as much heat as forced air cooling. Forced air cooling typically is achieved with fans which increase the operating noise of the multi-parameter light.
A technique found both in forced air cooled multi-parameter lights and convection cooled multi-parameter lights for dealing with excessive heat in the lamp housing involves the use of a thermal switch to turn off the lamp when the temperature inside of the lamp housing exceeds specification, and then to turn on the lamp when the inside of the lamp housing falls back to a cooler temperature.
FIG. 1
is a block diagram of a forced air cooled multi-parameter light which has a lamp housing
40
. The lamp housing
40
contains various optical components such as a reflector
45
, a lamp
46
, a condensing lens
47
, three filter wheels
48
,
49
and
51
, an iris diaphragm
50
(motor omitted for clarity), and a focussing lens
52
(motor omitted for clarity). The lamp housing
40
also contains a thermal switch
43
, a lamp power supply
44
, and a power supply
53
to power the lamp, various motors and electronics of the multi-parameter light. The electronics
41
within the lamp housing
40
include a communications node for receiving communication and command signals from a remote console (not shown) to vary the parameters of the multi-parameter light, and a microprocessor for operating the electromechanical system of motors (not shown for clarity) of the multi-parameter light as well as for turning on and off a fan
42
in accordance with the command signals. For cooling purposes, air enters the interior of the lamp housing
40
through a intake vent
54
, and is drawn through the lamp housing
40
by the fan
42
, and exits the lamp housing
40
through the fan and exhaust vent
42
. The thermal sensor
43
is located next to the ventilation exit near the fan
42
, and responds to the temperature at that point inside of the lamp housing
40
by opening the line power circuit if the temperature exceeds specification and closing the line power circuit when the temperature falls back into specification. If pan and tilt parameters are desired, a positionable reflector system (not shown) is provided after the focussing lens
52
and typically outside of the housing
40
, although the reflector system may be located inside of the housing
40
if desired.
FIG. 2
is a
Altera Law Group LLC
Lee Wilson
Wong Don
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