Light fixture with object detection system

A light fixture with a detection system includes a sensor subsystem with vehicle and personnel sensors. The detection system also includes an indicator/display subsystem with empty space, moving vehicle and personnel present indicators. The detection system further includes a control subsystem mounted in the light fixture and connected to the sensor and indicator subsystems for actuating the indicators in response to the signal inputs from the sensors. Applications of the detection system in parking structures and industrial facilities are disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to security lighting, and in 
particular to a light fixture for a parking facility with a detection 
system for detecting parking space status, moving vehicles and personnel 
in the vicinity of the parking space. 
2. Description of the Related Art 
Lighting fixtures are used for environmental control, i.e., illumination, 
and a variety of different designs have previously been developed to meet 
the requirements of particular applications. 
Light fixtures are commonly installed in various structures for security 
purposes. For example, parking garages comprise a class of structures 
which typically require illumination for safety and security. Since 
parking garages are often used during the hours of darkness, artificial 
illumination is desirable to reduce collision risks, enhance safety, etc. 
Moreover, parking garages are sometimes regarded as risky from the 
standpoint of personal attack. Such risks can be enhanced by the 
vulnerability of motorists as they enter and leave their vehicles and are 
thus preoccupied with retrieving vehicle keys, locking and unlocking 
vehicle doors, loading or unloading items in the vehicle, etc. Such 
activities tend to preoccupy motorists, and assailants have been known to 
time their attacks for such moments of vulnerability. 
Another security problem with parking structures is that vehicles parked 
therein afford numerous hiding places for would-be assailants. Other 
hazards associated with parking structures include collision risks 
associated with vehicles entering and leaving parking spaces. For example, 
when a vehicle backs out of a parking space, its driver's rearward vision 
is often limited, thus increasing the chances of a collision with a 
vehicle in the drive aisle. Another common problem encountered by 
motorists in parking structures relates to locating available spaces. 
Considerable amounts of unnecessary driving often occur as motorists 
traverse the drive aisles in large parking structures seeking empty 
parking spaces. 
A partial solution to safety and security issues associated with parking 
structures is to provide illumination by mounting light fixtures therein. 
However, the normal design standards for parking structure illumination 
require only relatively low illumination levels, e.g., about 0.5 foot 
candles per square foot. 
Light fixtures have previously been used for security purposes by coupling 
them with motion detection switching systems. For example, U.S. Pat. No. 
5,381,323; No. 5,434,764 and No. 5,442,532 disclose lighting fixtures with 
motion or proximity detectors. Such lighting fixtures can be used in areas 
in which illumination is desired when personnel are present. They tend to 
discourage intruders and would-be assailants by depriving them of the 
cover of darkness. 
Motion sensing electronics are well known in the art. For example, the 
Ravas U.S. Pat. No. 3,459,961 discloses a movement responsive light 
control means. The Ravas '961 patent motion sensor utilizes a doppler 
shift in a transmitted signal frequency to detect movement and thus 
trigger a firing circuit, which in turn switches a load (e.g., a light) to 
an on condition. Other sensor systems currently available utilize sonar 
and infrared technology to detect objects and object movement. 
Heretofore there has not been available a detection system for a light 
fixture with the safety and security advantages of the present invention. 
The present invention addresses some or all of the foregoing safety and 
security issues as they relate to parking structures and lighting system 
therefore. 
SUMMARY OF THE INVENTION 
In the practice of the present invention, a detection system is provided 
for a light fixture in a parking structure including a parking space, a 
drive aisle and a ceiling. The detection system includes a sensor 
subsystem with vehicle and personnel sensors, an indicator/display 
subsystem with empty space, moving vehicle and personnel indicators; and a 
control subsystem. The control subsystem includes memory, switching and 
logic units for receiving and storing data corresponding to predetermined 
situations and switching the indicators in response to signal inputs from 
the sensors. 
OBJECTS AND ADVANTAGES OF THE INVENTION 
The principle objects and advantages of the present invention include: 
providing a "smart" light fixture; providing a detection system for a 
light fixture; providing such a detection system which includes a vehicle 
detector; providing such a detection system which includes a personnel 
detector; providing such a detection system which is adapted for mounting 
in different types of light fixtures; providing such a protection system 
which is adapted for mounting in light fixtures installed in parking 
structures; providing such a detection system which is adapted for use in 
light fixtures installed in high bay industrial applications; providing 
such a light fixture which includes a programmable logic controller; 
providing such a detection system which can enhance safety and security in 
facilities where it is installed; and providing such a detection system 
which is economical to manufacture, efficient in operation, capable of a 
long operating life and particularly well adapted for the proposed uses 
thereof. 
Other objects and advantages of this invention will become apparent from 
the following description taken in conjunction with the accompanying 
drawings wherein are set forth, by way of illustration and example, 
certain embodiments of this invention. 
The drawings constitute a part of this specification and include exemplary 
embodiments of the present invention and illustrate various objects and 
features thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
I. Introduction and Environment 
As required, detailed embodiments of the present invention are disclosed 
herein; however, it is to be understood that the disclosed embodiments are 
merely exemplary of the invention, which may be embodied in various forms. 
Therefore, specific structural and functional details disclosed herein are 
not to be interpreted as limiting, but merely as a basis for the claims 
and as a representative basis for teaching one skilled in the art to 
variously employ the present invention in virtually any appropriately 
detailed structure. 
Certain terminology will be used in the following description for 
convenience in reference only and will not be limiting. For example, the 
words "upwardly", "downwardly", "rightwardly" and "leftwardly" will refer 
to directions in the drawings to which reference is made. The words 
"inwardly" and "outwardly" will refer to directions toward and away from, 
respectively, the geometric center of the embodiment being described and 
designated parts thereof. Said terminology will include the words 
specifically mentioned, derivatives thereof and words of a similar import. 
Referring to the drawings in more detail, the reference numeral 2 generally 
designates a detection system incorporated in a light fixture 4 having a 
base 4a and a lens 4b. Without limitation on the generality of useful 
applications of the detection system 2, it is shown mounted in a parking 
structure 6 including a plurality of parking spaces 6a,b,c; a drive aisle 
6d at the ends of the parking spaces 6a,b,c; and a ceiling 6e located 
thereover. 
The detection system 2 generally comprises a sensor subsystem 8, an 
indicator/display subsystem 10 and a control subsystem 12. The detection 
system 2 is designed to detect both vehicles 14 and personnel 16. 
II. Sensor Subsystem 8 
The sensor subsystem 8 includes a vehicle sensor 18 mounted on the fixture 
base 4a and directed at a respective parking space 6a. The vehicle sensor 
18 is adapted to provide a stationary vehicle presence signal to indicate 
occupancy of the parking space 6a, and a moving vehicle signal to indicate 
movement of a vehicle 14 with respect to the parking space 6a. A personnel 
sensor 20 is directed to the vicinity 6f of the parking space 6a and is 
adapted for emitting a "person present" signal if a person 16 is detected 
within such vicinity 6f 
The vehicle and personnel sensors 18, 20 can comprise any suitable sensor. 
For example, infrared sensors are available for detecting movement of 
heat-emitting objects, such as personnel and moving vehicles. Infrared 
sensors could be incorporated in both the vehicle sensor 18 and the 
personnel sensor 20. For detection of a stationary vehicle, the vehicle 
sensor 18 could employ sonar to transmit and receive signals for detecting 
the presence of a vehicle 14 in the parking space 6a. An optional, 
additional sensor is shown at 19 (FIG. 5). 
III. Indicator/Display Subsystem 10 
The indicator/display subsystem 10 includes a space available indicator 22, 
a person present indicator 24 and a moving vehicle indicator 26. The 
indicators 22, 24, 26 can be suitably color-coded, i.e., green, yellow and 
red respectively. The indicators 22, 24 and 26 can include, for example, 
light emitting diodes (LEDs) 22a, 24a, 26a respectively. Each indicator 
22, 24, 26 can also include a fresnel lenses 22b (green), 24b (yellow), 
26b (red) respectively, which lenses are mounted on the light fixture lens 
4b immediately outside respective LEDs 22a, 24a, 26a. The fresnel lenses 
22b, 24b, 26b function to enlarge the illumination patterns created by the 
LEDs 22a, 24a, 26a for greater visibility to an approaching motorist. An 
optional, additional LED is shown at 27 (FIG. 5). 
IV. Control Subsystem 12 
The control subsystem 12 includes a programmable logic controller (PLC) 28 
connected to a power source 30, which can comprise an alternating current 
source shared with the light fixture 4, a battery, or a combination AC and 
a rechargeable battery. Battery-powered capabilities for the detection 
system 2 have the advantage of providing emergency operation in the event 
of a power interruption. Thus, even if the light fixture 4 were not 
functioning, the detection system 2 could provide safety information to 
detect the presence of an intruder, a moving vehicle, etc. 
The PLC 28 includes a memory unit 32, a switching unit 34 and a logic unit 
36, all suitably interconnected with each other and with the sensor and 
indicator/display subsystems 8, 10 by suitable wiring 21. The memory unit 
32 is preferably programmable to receive data corresponding to 
predetermined conditions, such as the types of infrared signatures to 
which the control system will respond, and the sonar signature of a 
vehicle located within the parking space 6a. A suitable source of 
photoelectric sensors is Banner Engineering Corporation, P.O. Box 9414, 
Minneapolis, Minn. 55440. 
The logic unit 36 processes signals from the sensor subsystem 8 and 
actuates the switching unit 34 to illuminate or deilluminate the 
appropriate indicators 22, 24, 26. It will be appreciated that the PLC can 
be programmed to respond to a variety of different conditions as 
appropriate. 
V. First Modified Embodiment Detection System 102 
A detection system 102 comprising a first modified embodiment of the 
present invention is shown in FIGS. 6-7 and is installed in a high bay 
industrial type fixture 104 including a fixture base 104a mounted on the 
parking structure ceiling 106e and a fixture reflector 104b mounted on and 
depending downwardly from the fixture base 104a. 
The ceiling 106e on which the fixture 104 is mounted can be located at a 
substantial height, e.g., 15 feet to 25 feet high. Light fixtures such as 
that shown at 104 are commonly used for such relatively high 
installations. 
The detection system 102 is otherwise adapted for operating in a manner 
similar to the detection system 2, and includes a PLC 108 and a power 
source 130, similar subsystems to those described above. 
VI. Second Modified Embodiment Detection System 202 
A detection system 202 comprising a second modified embodiment of the 
present invention is shown in FIGS. 8-10 and is incorporated in a high bay 
industrial fixture 204 like the fixture 104 described above with a base 
204a and a reflector 204b. The fixture 204 is adapted for mounting on a 
parking or industrial structure ceiling 206e, which can be located a 
substantial distance, e.g., 15 to 25 feet, above a floor surface. The 
detection system 202 includes a PLC 208, such as the PLC 8 described above 
with sensor, indicator/display and control subsystems, and a power source 
230. 
The detection system 202 includes vehicle and personnel sensors 219, 221 as 
described above, and also includes an approaching vehicle sensor 214. A 
signal from the approaching vehicle sensor 214 is processed by the 
detection system 202 to determine a range and speed of an approaching 
vehicle 216. 
The PLC 208 includes a laser light source means 218 for emitting a 
directional laser beam 222. The detection system 202 further includes a 
laser reflector 220 mounted at approximately nominal visual height (e.g., 
about 4 to 8 feet) within the path of the laser light beam 222. The 
detection system 202, in addition to the functions described above, 
responds to the proximity of the approaching vehicle 216 when a potential 
hazard situation exists. For example, the detection system 202 can cause 
the laser light source 218 to emit a pulsating signal, visible on the 
laser reflector 220 to an approaching driver, when the approaching vehicle 
is within 25 feet. The pulsating signal can signify either a vehicle 
backing out of the parking space 6a, a person 217 in the vicinity 224 
thereof, or both. When the approaching vehicle 216 comes within a second 
predetermined range, e.g., 12 to 18 feet, the detection system 202 can 
cause the laser light beam 222 to be emitted continuously from the laser 
light source 218, thus indicating that the approaching vehicle 216 should 
stop. When the potential hazard leaves the vicinity of the parking space 
6a, the laser light source 218 would deactivate, thus signaling the 
approaching driver to proceed. 
It is to be understood that while certain forms of the present invention 
have been illustrated and described herein, it is not to be limited to the 
specific forms or arrangement of parts described and shown.