Infrared actuated control switch assembly

A switch assembly actuated by passive infrared radiation for operating a light in a space, the switch assembly including an optical system which senses infrared radiation over a 180.degree. range in horizontal plane including two separate vertical fields of view, a generally horizontal "look-out" field and a vertical semi cone-shaped "look-down" sensing field for directing to a common sensing element passive infrared radiation produced by a person moving within the sensing field of the switch assembly, the sensing element connected to a control circuit which responsively turns on the light, maintains the light on while the person remains in the space, and turns the light off automatically when the person leaves the space. The switch assembly includes a one-piece optical shell enclosed within a housing which is adapted for installation in a conventional light switch box in room. Another embodiment of the switch assembly is adapted for mounting on the exterior wall of a building for controlling the energization of an exterior light, turning the light on automatically whenever a person approaches the building.

BACKGROUND OF THE INVENTION 
This invention relates to passive infrared radiation actuated motion 
detection apparatus, and more particularly to a passive infrared actuated 
control switch assembly for controlling the operation of a functional 
device in response to detection of movement of a source of infrared 
radiation within an area monitored by the switch assembly. 
Presently, the operation of electric lights is controlled by manually 
operated switches. Wall switches are provided for controlling the 
energization and deenergization of ceiling mounted lamps or lamps plugged 
into electrical receptacles wired to the wall switch. A person entering a 
darkened room must search for the wall switch to turn on the room light. 
In the instance where the person is carrying articles and does not have a 
free hand for searching for the wall switch, the person must enter the 
room and set down the articles before groping for the light switch. 
Similarly, when a person is about to leave a room carrying a number of 
items, the person must either turn off the light before picking up the 
items before leaving the room, or must leave the room light on. 
It is common practice for persons leaving the room to leave the light on 
even though the person may not intend to return to the room. Thus, the 
room lights are maintained on even when they are not needed. This practice 
results in waste of energy. 
Thus, it would be desirable to have an arrangement for controlling the 
energization of a room light automatically and instantly in response to a 
person entering a room and which provides for deenergization of the light 
when the person exits the room. 
Likewise, it would be desireable to have an arrangement for controlling the 
energization of a porch light or yard light for a house or dwelling, for 
example, affording both convenience and safety for automatically turning 
the light on whenever someone approaches the house. This would both 
illuminate the approach to the house for the convenience and safety of the 
person approaching the house and alert occupants of the house to the fact 
that someone is approaching the house. In addition, this would save energy 
because the light would be turned on only when needed and would be turned 
off a short time after everyone has left the area illuminated by the 
light. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved control switch assembly which responds to variations in passive 
infrared radiation produced as the result of a movement of a source of 
infrared radiation within a given space and controls the operation of a 
functional device. 
It is another object of the present invention to provide a control switch 
assembly which responds to passive infrared radiation indicative of 
movement of a source of infrared radiation within a given space to 
energize a light within the space for illuminating the space. 
A further object of the present invention is to provide a control switch 
assembly which detects passive infrared radiation within a space, both in 
a 180.degree. generally horizontal look-out field extending generally 
forwardly the switch assembly and in a 180.degree. a shallow look-down 
field extending downwardly and outwardly from the switch assembly, and 
responds to variation in the infrared radiation detected, indicative of 
movement of a source of infrared radiation within a field of view of the 
switch assembly, to illuminate the space. 
Yet another object of the present invention is to provide a control switch 
assembly which detects passive infrared radiation within a space in two 
separate 180.degree. vertical fields of view including a shallow look-out 
field and a more vertical look-down field. 
Another object of the present invention is to provide an infrared radiation 
actuated control switch assembly for controlling the energization of a 
light bulb wherein the switch assembly is adapted for mounting in a 
conventional electrical wall switch receptacle for connecting electrical 
power to a light bulb that it controls for illuminating a room or other 
area of a house or building. 
Yet another object of the present invention is to provide an infrared 
actuated control switch assembly which is adapted for mounting on the 
exterior of a building for controlling the energization of an exterior 
light of the building in response to movement of a person within a sensing 
field for the switch assembly. 
The present invention provides an infrared radiation actuated control 
switch assembly responsive to infrared radiation within a given space for 
controlling a functional device in response to detection of variations in 
infrared radiation, indicative of movement of a source of infrared 
radiation within the space. 
The control switch assembly comprises sensing means including a sensing 
element responsive to infrared radiation; optical means; control circuit 
means; and housing means for containing said sensing means, said optical 
means and said control circuit means; said housing means constructed and 
arranged for mounting within the space; said optical means supported 
within said housing means and including first reflecting means, second 
reflecting means and focusing means, said sensing element being mounted in 
an operative relation with said focusing means, said first and second 
reflecting means each including planar reflecting means for reflecting to 
said focusing means infrared radiation in a first sensing field extending 
over a 180.degree. range and at a first predetermined semivertical angle 
within the space, said second reflecting means including further planar 
reflecting means for reflecting to said focusing means infrared radiation 
in a second sensing field extending over a 180.degree. range and at a 
second predetermined semivertical angle within the space, and said 
focusing means focusing onto said sensing element, infrared radiation from 
said first and second sensing fields reflected by said first and second 
reflecting means, said circuit means connected to said sensing element and 
responsive to said sensing element for providing an output for energizing 
the functional device in response to variation in infrared radiation 
focused onto said sensing element, indicative of movement of source of 
infrared radiation within the space. 
The invention consists of certain novel features and structural details 
hereinafter fully described, illustrated in the accompanying drawings, and 
particularly pointed in the appended claims, it being understood that 
various changes in the details may be made without departing from the 
spirit, or sacrificing any of the advantages of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring to FIGS. 1-3, the passive infrared actuated switch assembly 15 
incorporating the features of the present invention is described as being 
used to control the energization and deenergization of a light bulb 16 in 
a room. 
The passive infrared actuated switch assembly 15 includes a housing 20, a 
sensor module 22 mounted in the housing and a cover assembly including a 
conventional duplex wall plate 23 and a front cover bezel 24 secured to 
the sensor module by a screw 25. The housing is provided at its rearward 
surface 20a with a connector 27 which is adapted to receive power and 
ground wire of the conventional electrical wiring system for energizing 
the switch assembly 15. 
The switch assembly is provided with a mode switch 26 which enables the 
switch assembly to be operated in manual mode in which the light bulb 16 
is turned on or off by operating the switch 26 to the ON position or the 
OFF position, respectively. In the automatic mode, selected by operating 
the switch 26 to the AUTO position, the light bulb is turned on and off 
automatically under the control of the switch assembly. The light bulb is 
turned on when a source of infrared radiation moves within the detection 
fields of the switch assembly. The light bulb is turned off after a 
preselected time delay after movement of the infrared radiation is no 
longer sensed. The switch assembly includes a photocell 28 (FIG. 5A) and 
associated light lens assembly 29, including a light pipe 29a and a lens 
cover 29b, which enables the switch assembly to be inhibited whenever the 
ambient light is above a given level. The lens cover 29b, which is mounted 
on the front cover bezel 24, permits adjustment in the amount of ambient 
light conducted to the photocell 28 by the light pipe 29a. 
As shown in FIG. 3, the switch assembly is adapted to be installed in the 
electrical box (not shown) of an existing wall mounted light switch. By 
way of example, the switch assembly controls a light bulb 16 in a wall 
mounted light fixture which in turn is hard wired to the switch assembly 
15. However, the switch assembly may control a ceiling mounted light 
fixture or an electrical outlet into which is plugged a lamp or other 
functional device to be controlled. 
Referring to FIG. 5 in conjunction with FIGS. 1 and 2, the sensor module 22 
of the switch assembly 15 includes an optic shell 32 which defines 
reflective surfaces for focusing onto a sensor 41 infrared radiation 
produced by a person moving within the detection field of the switch 
assembly. As shown in FIG. 2, the optics shell 32 projects through an 
opening 23a in the front surface of the switch plate 23, and extends 
outwardly forward of the switch plate. This locates reflecting mirrors 70 
and 80, (FIG. 1) to receive infrared radiation in an arc 180.degree. in 
radius extending around the switch assembly from its left to right sides. 
As will be shown, the switch assembly 15 responds to the presence of a 
source of infrared radiation moving in the detection fields of the switch 
assembly to energize the light bulb 16. For purposes of illustration, the 
switch assembly 15 is described as responding to movements of a person 
within a room or space. However, the switch assembly responds to changes 
in infrared radiation levels and anything hotter or colder than ambient 
would be detected. The switch assembly maintains the light bulb 16 
energized as long as the person remains in the sensing field of the switch 
assembly 15 and movement of the person is sensed by the switch assembly. 
Once activated following the detection of infrared radiation, the switch 
assembly maintains the light bulb energized for a preset time period, 
adjustable for example, from ten seconds to eight minutes, even after 
movement of the person is no longer sensed. This delayed turnoff feature 
enables the switch assembly to keep the light bulb lit even though the 
person leaves the room or remains motionless in the room as when sitting 
down reading or watching television. 
The switch assembly 15 senses infrared radiation over a 180.degree. range 
in horizontal planes. The sensing range includes two separate fields of 
view, including a generally horizontal "look-out" or far field which 
extends forwardly of the switch assembly and a more vertical "look-down" 
or near field which extends forwardly and downwardly at a semivertical 
angle al relative to the horizontal. In one switch assembly which was 
constructed, the angle a1 was 32.degree.. Each field in vertical planes 
extends approximately 5.degree. on either side of center lines, 
represented by the dashed lines 30 and 31 for the "look-out" field and the 
"look-down" field, respectively. 
The effective lengths of sensing ranges for the "look-out" field and the 
"look-down" field are determined by the composition and configuration of 
the sensor used and by the size of the room in which the switch assembly 
is mounted. The sensor used in an exemplary embodiment had a maximum 
sensing range on the order of 20 feet. Preferably, the switch assembly 15 
is mounted on the wall of a room at a height of four feet, the standard 
height for wall switches. In such position, the sensing range for the 
"look-out" field extends at a radius of approximately twenty feet from the 
switch assembly at a height of four feet. As indicated the vertical extent 
of the "look-out" field is 10.degree., i.e. 5.degree. on either side of 
the horizontal center line. The maximum "look-down" field range for a 
semivertical angle of 32.degree. is within a radius of approximately 31/2 
feet at floor level from the location of the switch assembly. 
Generally, a person moving within the room will be within the look-out 
field unless that person is less than four feet tall or the person sits 
down. The look-down field is effective in certain of these conditions to 
turn the light on and/or maintain the light on. Thus, generally, the 
switch assembly is mounted in the wall light switchbox adjacent to a 
doorway to assure that a person of virtually any height entering the room 
is detected. A person entering the room through the doorway would have to 
pass through the "look-down" field and would then cause the light bulb to 
be lit and remain lit for at least the duration of the delayed turn off 
period. Assuming that the person moves to the center of the room, the 
person will pass out of the "look-down" field and should eventually pass 
into the "look-out" field because its vertical range increases in 
correspondence with distance from the location of the switch assembly, 
movements within either sensing fields being detected by the switch 
assembly to maintain the bulb lit. 
For the "look-down" field, there is a semi-circular dead zone having a 
radius of approximately two feet measured from a point directly beneath 
the switch assembly. However, a person would have to be less than two feet 
tall to fail to be sensed by the switch assembly. 
Thus, with an effective sensing range of approximately twenty feet, if the 
distance in a horizontal plane, from the switch assembly to each wall of a 
room is less than twenty feet, the wall mounted switch assembly 15 defines 
a sensing area for the switch assembly which covers an entire room, 
permitting detection of the movements of a person at least four feet tall 
anywhere in the room. 
Referring to FIG. 4, as will be shown, the switch assembly 15 provides a 
180.degree. "look-down" field having a generally horizontal sensing field 
approximately 180.degree. in angular extent, providing ten "look-out" 
sensing zones N1-N10 for the switch assembly. The sensing field is in the 
shape of a half cone. The end sensing zones N1 and N10 have an angular 
width of approximately 5.degree.. Each of the other sensing zones N2-N9 
has an angular width of approximately 10.degree., and is, for example, 
approximately 36" wide at a distance of about twenty feet radially outward 
from the switching assembly which is located at the mid-point. The longer 
the range, the greater the arc and the wider the field of view will be. 
The sensing zones N1-N10, and the spaces between adjacent zones, such as 
space 51 between zones N1 and N2, space 52 between zones N2 and N3, etc., 
are determined by the configuration of the optical system and of the 
infrared sensor of the switch assembly as will be described. 
Referring to FIG. 4, the "look-down" field is also in the shape of a half 
cone sensing field which has the same projections in a horizontal plane as 
the "look-out" field but is at the semivertical angle al. The "look-down" 
field includes ten "look-down" sensing zones which are defined similar to 
the sensing zones N1-N10. The "look-down" sensing zones have been labeled 
D1, D2, . . . D9, D10 in FIG. 4. The end sensing zones D1 and D10 have an 
angular extent of 5.degree.. Each of the other sensing zones, such as 
zones D2 and D9, has an angular width of approximately 10.degree. and is 
approximately 12" wide at a distance of 31/2 feet radially outward from 
the switch assembly. 
Referring to FIGS. 1-4, in summary, as indicated above, the control switch 
assembly 15 is mounted in a switch box in a wall within a room, generally 
on one side of a doorway, performing the function of the wall switch which 
would normally be mounted in such switch box. The switch assembly 15 
controls the energization of a light bulb 16 in response to movement of a 
person within the room. 
Referring to FIGS. 3 and 4, as indicated, the switch assembly senses 
infrared radiation in a generally horizontal look-out field 180.degree. in 
angular width and having ten zones N1-N10, sensing zones N2-N9 being 
10.degree. in angular width and zones N1 and N10 being 5.degree. in 
angular extent. In addition, the switch assembly senses infrared radiation 
in a shallow vertical 180.degree. look-down zone at a semivertical angle 
of 32.degree. in the illustrative embodiment. The look-down field also 
includes ten sensing zones D1-D10, including eight zones D2-D9 which are 
10.degree. in angular extent and two zones D1 and D10 which are 5.degree. 
in angular extent. 
Thus, when a person enters the room through the doorway, and moves into the 
room, the person will move through several of the look-down zones D1-D10, 
such as zone D1, and assuming that the person is at least four feet tall 
through several of the look-out zones N1-N10, such as zones N1, N2, etc., 
in succession. Upon entering the room, the person first moves into zone D1 
and N1. The infrared radiation emitted by the person will be sensed in 
zone N1 of the look-out field, causing the light bulb 16 to be lit. A 
person less than four feet tall will be detected by infrared radiation 
sensed in zone D1 of the look-down field which would cause the light bulb 
16 to be turned on. For a room having a maximum distance of 20 feet from 
the switch assembly mounting location to any wall laterally or forwardly 
of the switch assembly, movements of the person within the room will be 
sensed, maintaining the light bulb 16 lit. Because the switch assembly is 
mounted at a height of only four feet, and because its vertical field 
increases with distance from the switch assembly, infrared radiation 
generated by a person at least four feet tall will be sensed at virtually 
every point in the room. 
If the person is less than four feet tall, as such person moves past the 
switch assembly 15 and into the room, the person will eventually pass out 
of the look-down sensing field, when the person reaches a point 
approximately 31/2 feet forward of or to either side of the switch 
assembly. However, as indicated, the vertical extent of the look-out field 
increases as a function of distance away from the switch assembly 15 and 
at a distance 31/2 feet from the location of the switch assembly, the 
vertical extent is approximately 12". Accordingly, a person at least three 
feet tall would be sensed by the look-out field at a distance of about 
31/2 feet from the location of the switch assembly. 
As long as the person continues to move within the room and within the 
sensing fields of the switch assembly, infrared radiation generated by 
that person will be sensed, maintaining the light bulb lit. Even if the 
person sits down within the room, the slightest movement of the person 
will serve to maintain the lamp lit. When infrared radiation fails to be 
sensed within the turn off delay time provided by the switch assembly, the 
light bulb will be turned off. 
Switch Assembly 
Referring to FIGS. 5 and 5A, assembled as shown in FIG. 5B, there is 
provided an exploded perspective view of the housing 20 and sensor module 
22 of the switch assembly 15 in simplified form. The switch assembly 15 is 
oriented in the vertical direction in FIGS. 5 and 5A, for clarity of the 
drawings, but as shown in FIGS. 1 and 2, in use, the switch assembly is 
oriented in a horizontal direction. Thus, in the following description, 
upper and lower surfaces, and forward and rearward surfaces of the 
elements of the assembly are as for the normal use position (FIGS. 1 and 
2). As shown in FIG. 5, the sensor module 22 includes an optics shell 32, 
a sensor assembly 33 and a mounting bracket 34. The sensor module 22 
further includes a circuit assembly 35, shown in FIG. 5A. 
Referring to FIG. 5, the sensor assembly 33 includes an infrared sensor 41, 
a sensor carrier 42, a connector 43, and a sensor printed circuit board 
44. The sensor assembly 33 is adapted for mounting within the optics shell 
32. As will be shown, the optics shell 32 in turn is adapted for mounting 
on the mounting bracket 34 with the sensor assembly 33 contained 
therewithin. A sensor lens 45 encloses the upper portion of the optics 
shell 32. 
With reference to FIGS. 5 and 5A, the housing 20 is a hollow box-like 
member rectangular shape and which is open at its forward end. The 
mounting bracket 34 is adapted for mounting on the housing 20 at its open 
end with the circuit assembly 35 attached to the under surface 34a of the 
mounting bracket 34 and depending therefrom and located in the housing 20 
in the assembled unit. 
The circuit assembly 35 includes a printed circuit board 51, a printed 
circuit board mounting bracket 52, and a pair of PUSH-LOK wire type wire 
terminals 53 and 54. The circuit assembly also includes the mode switch 
26, photocell 28 and light lens assembly 29. 
Optics Shell 
Considering the optics shell 32 in more detail, with reference to FIGS. 
6-9, the optics shell 32 is a one-piece molded unit of a rigid material 
having electrically insulating characteristics and which is metalized all 
over and conductive at line voltage, acting as a shield for the sensor 43 
(FIG. 5) contained therewithin when the unit is assembled. One such 
material suitable for this use is Cyclolac ABS, commercially available 
from Borg-Warner. Preferably the reflective material is aluminum and is 
applied to the optics shell 32 by vacuum deposition. 
Referring to FIGS. 5-8, the optics shell 32 has a generally 
semi-ellipsoidal cross-section defined by a pair of flat upper and lower 
walls 61 and 62 having flat outer surfaces 61a and 62a and arcuate side 
walls 63 and 64, the side walls being joined by an integrally formed 
arcuate bridge 65 which defines the forward surface of the optics shell 
32. The bridge 65 extends over only the middle one-third of the forward 
surface of the optics shell defining openings 78 and 79 at the top and 
bottom of the forward surface of the optics shell. A mounting flange 67 
extends around the periphery of the optics shell at its open rearward end. 
The upper surface 67a of the flange 67 defines a pair of horizontally 
extending posts 68 which index the lens 45 (FIG. 5) to the optics shell. 
The lens 45 is provided with apertures 45a which receive the posts 68. The 
flange further defines a pair of depending hooks 69 which facilitate 
attachment of the optics shell to the mounting bracket 34 (FIG. 5) as will 
be shown. 
Referring to FIGS. 6-9, the upper wall 61 defines a curved reflective 
mirror 70 generally convex in shape and including six generally 
trapezoidal shaped flat segments 71-76 formed as an integral arcuate 
projecting downwardly and inwardly at an angle cl, relative to the plane 
of the upper wall 61 into the cavity of the optics shell from the front 
edge of the upper wall 61. As shown best in FIG. 6, the innermost or lower 
edge 70a of mirror 70, and thus edges of the elements 71-76 terminate at a 
height corresponding approximately to the upper edge 65a of the arcuate 
bridge 65. 
Similarly, the lower wall 62 defines on its upper surface a reflective 
mirror 80, generally convex in shape, comprised of six flat segments 
81-86. The segments 81-86 project upwardly and inwardly into the cavity of 
the optics shell from the front edge of the lower wall 62 and towards the 
rear of the optics shell. The segments 81-86, which are generally 
trapezoidal in shape, are divided into pairs of elements 81a-86a and 
81b-86b along a fold line 87. Elements 81a-86a extend at the same angle c1 
as elements 71-76 whereas elements 81b-86b extend at a less acute angle 
d1. The inner segments 72-75 are 20.degree. in arcuate width, with the 
centermost segments 73 and 74 having their axis offset 10.degree. from the 
center axis of the optics shell. The planes of segments 71-76 are inclined 
at an angle c1 of 30.degree. relative to the plane of the upper wall. 
Thus, referring to FIG. 4, segments 73 and 74 which, in part, define 
respective sensing zones N5 and N6 are centered on axis at 80.degree. and 
100.degree., segments 72 and 75 which define sensing zones N4 and N7 at 
60.degree. and 120.degree.. Segments 71 and 76 which define zones N1-N3 
and N8-N10 extend over a range of 0.degree. to 50.degree. and 130.degree. 
to 180.degree.. 
Similarly, inner segments 82-85 are 20.degree. in arcuate width with the 
centermost segments 83 and 84 having their axis offset 10.degree. from the 
center axis of the optics shell. The planes of segments 81a-86a are 
inclined at an angle cl of 30.degree. relative to the upper wall, and 
segments 81b-86b are inclined at angle d1 of 16.degree. relative to the 
upper wall. Segments 83,84 and 82,85 and 81,86 which define respective 
sensing zones D5,D6 and D4,D7 and D1-D3, D8-D10, are disposed on the same 
angular displacements as segments 73,74 and 72,75 and 71,76, respectively. 
Segments 71-76 and 81a-86a define the "look-out" reflector surfaces for the 
optics shell. Segments 81b-86b define the look-down reflector surfaces for 
the optics shell. 
The mirrors 70 and 80 extend in a generally parallel opposing relation with 
one another, with mirror 80 being located on the top inner surface of the 
optics shell 32 and mirror 70 being located on the lower inner surface of 
the optics shell 32. The openings 78 and 79 permit infrared radiation to 
impinge on the mirrors 70 and 80 from the front of the optics shell 32. 
The inner surface of the arcuate bridge 65 defines the focusing mirror 90 
which includes two major reflective surfaces 91 and 92 and two minor 
reflective surfaces 93 and 94. The major reflective surfaces 91 and 92 are 
formed as spherical surfaces having a radius of curvature in the vertical 
plane of 0.781 for the in use orientation of the optics shell. The minor 
reflective surfaces 93 and 94 have a radius of curvature of 1.036 in the 
vertical plane for the in use orientation of the optics shell. The 
focusing mirrors 91-94 define the 10.degree. sensing width in the vertical 
direction for the look-down field and the look-out field. Surface 91 
slants forwardly and upwardly, terminating in an inwardly projecting 
reflective edge portion defining reflective surface 93. Reflective surface 
92 slants forwardly and downwardly, terminating in an inwardly projecting 
edge portion defining reflective surface 94. The reflective surfaces 91 
and 94 focus on the sensor infrared radiation impinging on the segments 
71-76 of the mirror 70 located in the upper portion of the optics shell. 
The reflective surface 92 focuses onto the sensor infrared radiation 
impinging on the segments 81a-86a of the mirror 80 in the lower portion of 
the optics shell. The mirror segment 93 focuses onto the sensor infrared 
radiation impinging on segments 81b-86b of the mirror 80 in lower portion 
of the optics shell. 
Index members 95 and 96, projecting rearwardly from the forward inner 
surface of the optics shell at opposite ends of the arcuate member index 
the optics shell 32 to the sensor holder 42 (FIG. 5) as will be shown. 
Index pins 97 extending rearwardly from diametrically opposed positions at 
rearward corners of the top and bottom walls index the optics shell to the 
sensor printed circuit board. 
Sensor Assembly 
Referring to FIGS. 10-15, the infrared sensor 41 may, for example be the 
type disclosed in the U.S. Pat. No. 4,379,971. The sensor 41 comprises a 
pliable pyroelectric film material 101 such as polyvinyldine fluoride 
(PVF2) which forms the base substrate for the sensor. 
Briefly, the surface 102 of the pyroelectric material 101 which is 
designated as the front of the sensor is essentially covered with a 
continuous overlay 103 of an electrically conductive material which forms 
an electrostatic shield and a solid electrode for one side of the 
radiation sensor. The electrode arrangement provides six enlarged fingers 
106a-106f, alternate fingers 106a, 106c, and 106e interconnected in 
electrical series by conductor 105 to form one electrode 109 and fingers 
106b, 106d, and 106f interconnected by conductor 110 to form a second 
electrode 111. 
The infrared sensor is arranged in an elongated rectangular configuration 
so that energy striking the mirrors 70, 80, 90 (FIG. 8) is focused on the 
surface of the sensor generally along its longitudinal axis as the source 
of radiation moves within the sensing field. 
As a source of infrared energy in the horizontal plane that is being 
observed, passes in front of the mirror, a varying output signal from the 
sensor is generated. As the focused energy is aligned with one set of 
electrodes 109 or 111, the output voltage from that set of electrodes will 
be increased generally in a positive direction and the output from the 
other electrode set will remain essentially constant. The six electrode 
"fingers" define six sensing zones for each sensing field. The optical 
systems reverse the direction of the sweep of the focused radiation when 
the radiant energy is directed to the outermost "fingers" 106a and 106f. 
As the focused energy is directed between the two electrodes minimum 
output signal is provided by the sensor, these intermediate areas thus 
defining the "spaces", between sensing zones, such as N1, N2 and N2, N3, 
etc. 
As the energy source moves to the left, for example, the localized focus F 
of the energy on the surface of the sensor moves to the right to point F1 
as illustrated and the output voltage from electrode (i.e. finger 106a) 
will increase. As the focus point of the energy moves across the sensor in 
the axial direction away from point F1, the output from the electrode 109 
returns to the original voltage. The output voltage from the other 
electrode (i.e. finger 106b) will progressively increase as the focus 
point of the energy moves toward point F2 and approaches finger 106b of 
this electrode. As the focus point crosses an electrode and moves toward 
point F3, the output from the electrode will again return to its original 
voltage with an increase again being observed in the voltage output for 
electrode as the focus point of the energy approaches finger 106c. 
The sensor holder 42 has a generally arcuate center portion 131 defining a 
pair of spaced apart bridge members 132 and 133, defining a rectangular 
opening 134 therebetween, and joined at their bottom ends by end portions 
135 and 136. The inner surface of the arcuate members 132 and 133 is cut 
away represented by the dashed line 137 defining a recessed inner surface 
138 which receives the flexible sensor 41 (FIG. 14). 
The radius of curvature of the center portion 131 corresponds generally to 
one-half the radius of curvature of the inner surface of the arcuate 
bridge portion 65 of the optics shell (FIG. 7) at the junction of the two 
major reflective surfaces 91 and 92, to locate the sensor 41 at the focal 
point for focusing mirrors 90 (FIG. 8) which for the spherical mirrors is 
at one half the radius of curvature of the mirrors as shown in FIG. 16A. 
As shown in FIG. 5, portions of the fingers 106a-106f of the sensor 
element are exposed to view through the channel or opening 134 defined by 
the spaced apart members 132 and 133. 
The ends of the holder define indexing slots 139, 139a, the slot 139 being 
semi-circular for end portion 135 and the slot 139a being generally 
rectangular for end portion 136. These keyed apertures register with the 
pins 95,96 on the optics shell 32 (FIG. 9). End portion 136 has legs 136a 
spaced apart to define a generally rectangular trough 140 on its 
undersurface which receives the Zebra connector 43 (FIG. 5) for connecting 
the electrodes of the sensor to the control circuit as will be shown. Legs 
136a and legs 135a on end 135 support the holder 42 on the printed circuit 
board with the sensor 41 spaced from the upper surface of the printed 
circuit board. 
Referring to FIG. 5, the Zebra connector 43 interconnects the electrodes of 
the sensor with conductors 44a on the printed circuit board 44. The sensor 
printed circuit board 44 carries the input stage of the control circuit 
(FIG. 18), including operational amplifiers 187 and 187a and the 
associated components enclosed within the dashed line. The input stage has 
four output conductors 42c connected to four output terminals 44b 
extending downwardly from its undersurface for connecting the signal 
outputs of the input stage to signal processing and output stages of the 
control circuit by way of connector block 139 carried on the printed 
circuit board 51 (FIG. 5A). 
Circuit Assembly 
Referring to FIGS. 5A and 18, the printed circuit board 51 mounts the 
components of the control circuit, shown in diagrammatic form in FIG. 18. 
The control circuit responds to the infrared sensor 41 and generates 
control signals for causing energization and deenergization of the light 
bulb 16 (FIG. 3) controlled by the switch assembly 15. The output stage of 
the control circuit includes a triac 59 which is connected in series with 
the light bulb 16 being controlled and the power conductors. 
The two electrical contact assemblies 53,54, embodied as PUSH-LOK type wire 
terminals, are mounted on the printed circuit board to facilitate 
connection of electrical power to the circuit carried by printed circuit 
board. The electrical wires (not shown) of the electrical wiring 
installation in which the switch assembly is installed are plugged into 
the terminals through openings in the connector body 27 (FIG. 2) formed in 
the rear wall 20a of the housing 20. 
The mode switch 26 is mounted on the printed circuit board 51 near its 
lower edge 51a. The mode switch 26 includes a conventional slide switch 
151 having its terminals extending outward from its rearward surface into 
apertures (not shown) in the printed circuit board 51, for connecting the 
switch 151 into the control circuit. A toggle assembly including a pivot 
152 and toggle arm 153 is mounted on the forward surface of the switch 
151, the toggle arm 153 having a hollow bore (not shown) at its base which 
overlies the switch arm (not shown) of the slide switch 151, enabling the 
switch arm to be operated between its three positions by pivoting the 
toggle arm 153 about the pivot axis 152a. 
As shown in FIGS. 1 and 2, the free end 153a of the toggle arm 153 extends 
through an opening 24a in the forward surface of the cover bezel 24 to 
permit operation of the switch to select the operating mode for the switch 
assembly. 
Referring again to FIG. 5A, the photocell 28 is mounted on the printed 
circuit board at its lower edge 51a. The light lens assembly 29 includes 
light pipe member 29a and lens cover 29b. The light pipe member 29a is a 
generally "T" shaped element having a generally rectangular shank portion 
154 which terminates in a generally flat rectangular top lens portion 154a 
which extends horizontally in the switch unit and serves as a light 
collector to focus or channel ambient light from outside of the switch 
assembly to the shank of the light pipe member, the tip of the shank being 
located in overlying relationship to the photocell 28 in the assembled 
switch unit. The lens cover 29b is a generally rectangular element with a 
ridged or serrated upper or forward surface 155, the element conforming in 
size and shape to the rectangular lens portion of 154a of the light pipe 
member 29a and adapted to slide along the forward surface thereof into a 
channel (not shown) in the forward portion of the bezel 24. 
Referring to FIG. 1, when the lens cover 29b is operated to the left, as 
viewed in FIG. 1, the lens cover is moved out of the way, exposing the 
upper light collecting surface 154a of the light pipe member 29a. This 
transmits maximum ambient light to the photocell 28. When the lens cover 
29b is moved to the right such that the handle portion 155c abuts the 
right wall 24b of the opening in the bezel 24, the ridged surface 155 of 
the lens cover 29b reflects away ambient light, minimizing the amount of 
ambient light which is transmitted to the photocell 28. 
Referring to FIGS. 5 and 5A, the printed circuit board mounting bracket 52 
includes a generally trapezoidal shaped plate portion 52a having a pair of 
bifurcated legs 52b and 52c depending therefrom, the free ends of the legs 
terminating in hook portions 156 which pass through slots 157 formed on 
the opposite sides of the printed circuit board 51, with outwardly 
projecting shoulders 158 engaging the under surface of the printed circuit 
board 51 for supporting same. The upper surface of the plate 52a has a 
plurality of apertures 159 formed therethrough and aligned with the 
openings in the terminal connector 139 through which pass the terminals 
44b of the sensor assembly (FIG. 5) in the assembled unit. A pair of posts 
160 extend upwardly from the surface 52a to facilitate securing the 
mounting bracket 52 to the printed circuit board mounting bracket 34 as by 
swaging. The posts 160 pass through apertures 161 (FIG. 5) in the mounting 
bracket 34. The plate 52a has a pair of generally rectangular slots 162 
formed near its upper edge on either side thereof and which are aligned 
with correspondingly shaped slots 163 in the mounting bracket 34 and 
through which pass the hooks 69 of the optics shell 32 when the unit is 
assembled. The plate 52a also includes a boss 164 which includes a 
threaded insert 165 which facilitates mounting or securing the duplex 
cover plate (FIG. 1) and front cover bezel 24 to the unit by the screw 25. 
An aperture 166 in the plate 52a enables access to a trim potentiometer 
198 (FIG. 18) connected in the control circuit for adjusting the turn off 
delay time of the control circuit for the switch assembly. 
Continuing to refer to FIGS. 5 and 5A, the mounting bracket 34 is generally 
rectangular in shape and has its upper and lower end portions 171 and 172 
extending offset relative to the plane of the main body portion 170 of the 
mounting bracket 34 and provided with apertures 171a and 172a to 
facilitate attachment of the mounting bracket and the elements supported 
thereby to the switch box. The slot 173 is aligned with apertures 159 in 
plate 52a to provide pass through for the terminals of the sensor printed 
circuit board 44 to the connector 139 carried on the printed circuit 
board. Boss 164 on the printed circuit board mounting bracket 52 passes 
through an aperture 177 at the center of the mounting bracket 34. Aperture 
178 is aligned with aperture 166 to provide access to the potentiometer 
198 (FIG. 18) for adjusting the turn off delay time. A projection 175 at 
the rearward side of the mounting bracket 34 at its lower end connects the 
triac 59 to the metal mounting bracket which serves as a triac heat sink, 
the triac 59 being secured to the projection 175 in heat transfer 
relationship by a retainer clip 150. 
The mounting bracket 34 is provided with four rectangular apertures 174 
near the corners of its main body portion 170 through which pass the hooks 
20a at the upper surface of the housing 20, providing a snap fit for 
securing the mounting bracket 34 to the housing 20. A generally 
rectangular opening 176 is provided at the bottom of the mounting bracket 
34 to provide a pass through for the toggle switch assembly 26 and the 
light pipe assembly 29. 
Control Circuit 
Referring to FIG. 18, the control circuit includes an input stage 180, a 
comparator stage 181, a drive stage 182, an output stage 183 and a power 
supply stage 184. 
The power supply stage 184 includes a 24 volt Zener diode bridge network 
185 connected between the ground conductor B and hot conductor W providing 
an unregulated voltage at 24 VDC between conductor L1 and ground conductor 
B. This voltage is applied to a voltage regulator 186 which applies a 
regulated DC voltage at 12 VDC between conductor L2 and ground B. 
The sensor 41 is connected to the input stage 180 which comprises a pair of 
operational amplifiers 187 and 187a which are connected in tandem for 
operation as a low pass filter to filter out 60 Hz noise. Amplifier 187 
has its non-inverting input connected through a resistor 188 to sensor 
electrode 109 and through resistor 188a and a further resistor 188b to the 
ground reference. The inverting input of amplifier 187 is connected 
through a resistor 189 to electrode 111 of the sensor 41. The output of 
amplifier 187 is connected through resistors 190 and 190a and through 
resistor 188b to the ground reference and is connected through a feedback 
network including a capacitor 191 to the inverting input of the amplifier 
187. The inverting input of amplifier 187 is also connected through a 
resistor 191a to the junction of resistors 190 and 190a. The output of the 
amplifier 187 is also coupled trough a capacitor 192 and a resistor 192a 
to the inverting input of the amplifier 187a which has its non-inverting 
input connected to the ground reference and its output connected through 
parallel connected resistor 193 and capacitor 193a to the inverting input 
of the amplifier 187a. 
The output of amplifier 187a of the input stage 180 is connected to the 
input of the comparator stage 181 which is comprised of a pair of diodes 
194, 194a and a comparator 195 connected for operation as a window 
comparator circuit to provide an output indicative of whether or not the 
input signal provided by the sensor 41 is within a predetermined range. 
The output of amplifier 187a is connected through diode 194 to the 
inverting input of comparator 195. A voltage divider comprised of series 
connected resistors 194a and 194b is connected between conductor L2 and 
ground establishing a reference voltage Va at the inverting input of 
comparator 195, which is connected between the junction of resistors 194a 
and 194b. The non-inverting input of comparator 195 is connected through 
diode 194a to the output of amplifier 187a and to the junction of series 
connected resistors 195a and 195b which establish a reference voltage Vb 
at the non-inverting input of the comparator 195. 
The output of comparator 195 is connected through a resistor 196 to the 
non-inverting input of a comparator 197. A time delay network including 
series connected potentiometer 198, a resistor 198a and capacitor 198b are 
connected between conductor L2 and ground, the junction of potentiometer 
198 and capacitor 198b being connected through resistor 196 to the 
non-inverting input of comparator 197. Capacitor 198b provides a time 
delay shutoff feature to maintain the drive stage enabled for a time 
interval, such as four minutes, following termination of detection of 
infrared radiation by the input stage. Comparator 197 has its inverting 
input connected to a voltage divider formed by resistors 199, 199a and 
199b which are connected in series between conductor L2 and ground. The 
output of comparator 197 is connected through resistor 200 and diode 200a 
to its non-inverting input, and to the inverting input of comparator 201 
of the drive stage 182 and through resistor 202 to conductor L2. 
Comparator 201 has its non-inverting input connected to a reference 
potential at the junction of resistors 199a and 199b at point 205. 
The output of comparator 201 is connected through a resistor 202 to the 
gate of a field effect transistor 203 which has its source-to drain 
circuit connected in series with a resistor 204 between the line input at 
the conductor W, which is connected to the hot wire terminal through the 
lamp 16 and the conductor B which is connected to the ground terminal. 
The output stage 183 includes the triac 59, a breakover device 205 and a 
capacitor 206. The triac is connected in series with the lamp 16 between 
the conductor W connected to the hot terminal and the conductor B 
connected to the ground terminal. The breakover device 205 is connected 
between the gate of the triac 59 and the drain electrode of the field 
effect transistor 203 at the output of the drive stage 182 at point 207. A 
capacitor 206 is connected between the output of the drive stage 182 at 
point 207 and the conductor B connected to ground terminal. 
Mode switch 26 is connected in shunt with the triac 59 with its terminal 
"AUTO" connected to the conductor W, its terminal "OFF", unconnected, and 
its terminal "ON" connected to ground. The switch arm 26a is connected to 
one side of the lamp, the other side of which is connected to the hot wire 
of the AC power source. 
For the purpose of inhibiting the control circuit during daylight hours, 
the photocell 28 is connected in an inhibit network 210 to provide an 
inhibit input to comparator 201. The photocell 28 is connected in series 
with resistors 211, 211a between conductor L2 and ground. Diodes 212, 212a 
which are connected in series between ground and conductor L2 provide a 
reference voltage at point 213. A diode 214 is connected between the 
junction of the photocell 28 and the resistor 211a at point 215 and point 
213. Diode 216 connects point 215 to the inverting input of comparator 
201. The cathode of diode 216 is connected through capacitor 217 and a 
resistor 218 to ground. 
The reference voltage applied to the non-inverting input of comparator 201, 
at point 205a, is also connected through a resistor 219 to the 
non-inverting input of a comparator 220 which has its inverting input 
connected to the junction of diodes 212, 212a and its output connected to 
the inverting input of comparator 195. A resistor 221 is connected in a 
feedback path between the output of comparator 220 and its non-inverting 
input. 
Assembly 
In assembling the switch assembly 15, referring to the circuit assembly 35, 
FIG. 5A, the printed circuit board mounting bracket 52 is mounted on the 
printed circuit board 51 with its bifurcated legs 52b and 52c positioned 
with their hooked end portions 158 located in the lateral slots 158 on 
either side of the printed circuit board 51. The circuit assembly 35 is 
then secured to the under surface 34a of the mounting bracket 34, FIG. , 
with posts 160 extending through apertures 161 in the mounting bracket and 
swaged to secure the circuit assembly 35 to the mounting bracket 34. The 
tab 175 is connected to the triac 59 by clip 150 to heat sink the triac to 
the mounting bracket 34. 
Referring now to FIGS. 5-9 and 16A, in the sensor assembly 33, the sensing 
element 41 is located in the recess formed in the under surface of the 
sensor holder 42 and connector 43 is located in the channel 136b. The 
sensor holder 42 and sensor 41 thus assembled are positioned on the sensor 
printed circuit board 44, and this sub-assembly is positioned on the 
mounting bracket 34 with terminals 44b extending through aperture 173 with 
their distal end plugged into the connector block 139 openings. The optics 
shell 32 is then positioned over the sensor assembly 33 with its index 
pins 95 and 96 located in the indexing slots 135a and 136a in the sensor 
holder 42 and with its indexing pins 97 located in the indexing apertures 
44c in the sensor printed circuit board 44. In addition, hooks 69 of the 
optics shell 32 are aligned with apertures 163 in the mounting bracket 34 
and the optics shell is then pushed onto the mounting bracket 34 allowing 
the hooks 69 to pass through the apertures 163 and flex back securing the 
optics shell 32 and the sensor assembly 33 contained therewithin on the 
mounting bracket. 
Referring to FIG. 16A, in this sub-assembly, the sensor assembly 33 is 
located with its open upper channel 41 facing the inner concave mirrored 
surface of the optics shell which defines the focusing mirrors 90. As can 
be seen, the curved sensor 41 extends in arcuate fashion along the concave 
curved inner surface of the optics shell 32, enabling the sensor element 
41 to be located at the focal points of the four focusing mirror elements 
defined by the focusing mirror 90. 
Referring again to FIG. 5, the lens 45 is positioned on the optics shell 32 
with its locator holes 45a aligned with locator pins 68 which pass through 
the apertures 45a. 
The mounting plate 34 with the circuit assembly 35 attached to its under 
surface 34a and the sensor assembly 33 and optics shell 32 secured to its 
upper surface 34b is then mounted on the housing 20 with the circuit 
assembly 35 extending into the open forward end thereof and hooks 20a of 
the housing 20 aligned with apertures 174 in the mounting bracket 34. The 
mounting bracket 34 is then pushed onto the housing allowing the hooks 20a 
to pass through the apertures 174 and snap into place securing the sensor 
module to the housing 20. 
Referring now to FIGS. 1 and 2, the housing with the sensor module mounted 
thereon is positioned in a switch box (not shown) and secured thereto by 
screws which pass through the mounting slots 171a,172a (FIG. 5) of the 
mounting bracket. The duplex wall switch plate 23 is then positioned over 
the front surface of the assembly and the front cover bezel 24, with the 
light lens assembly 29 mounted therein is positioned over the forward 
surface of the wall plate 23 and secured thereto and to the mounting plate 
34 by screw 25 which is received in the threaded insert 165 in projection 
164 (FIG. 5A) on the printed circuit board mounting bracket 52. As shown 
in FIGS. 1 and 2, the free end 153a of the mode switch 26 projects through 
the forward surface of the cover assembly as does the optics shell 32 
enclosed within lens 45. As shown, the optics shell reflecting mirrors 70 
and 80 project outwardly relative to the plane of the covers and so 
located to allow infrared radiation in a 180.degree. arc around the 
forward and to the sides of the switch assembly to impinge directly on the 
reflective mirrors 70 and 80 for reflection onto the focusing mirror. 
Operation of the Switch Assembly 
The manner in which the switch assembly focuses infrared radiant energy 
present in its detecting fields onto the sensor 41 is described with 
reference to the simplified views of the switch assembly 15 with the 
radiation patterns illustrated in FIGS. 16 and 17. 
Referring to FIG. 16, infrared radiation directed, toward the switch 
assembly 15 in a horizontal plane (.+-.5.degree.) at a height at about 
four feet, at the top thereof, represented by rays 331 and 332, directed 
toward the switch assembly 15 from the top of the horizontal field line is 
reflected by the planar mirror 70, as rays 331a and 332a, to the focusing 
mirror 90. The segment 91 of the focusing mirror 90 focuses the radiation 
as ray 331b onto the sensor 41 which is located at the focal point of 
segment 91 of the focusing mirror 90. Similarly, the segment 94 of the 
focusing mirror 90 focuses the radiation as ry 332b onto the sensor 41 
which is located at the focal point of the mirror segment 94. 
Similarly, infrared radiation directed generally horizontally towards the 
switch assembly from the bottom of the horizontal field, as ray 333, 
impinges on one of the mirror segments 80a and is reflected to focus 
mirror 92 as ray 333a. This radiation is focused on the sensor 41 as ray 
333b. 
Infrared radiation directed toward the switch assembly 15 at an angle of 
approximately 28.degree. (.+-.5.degree.) from the horizontal is received 
in the "look-down" field, represented by ray 334. This radiation impinges 
on one of the segments 80b of mirror 80. The radiation is reflected 
upwards by the mirror segment 80b as ray 334a onto the segment 93 of the 
focusing mirror 90. The focusing mirror segment 93 focuses the radiation, 
as ray 334b, onto the sensor 41 which is located at the focal point of the 
focusing mirror segment 93. 
With reference to FIG. 17, considering now the operation of the optical 
systems of the switch assembly 15 in receiving infrared radiation in the 
sensing fields N1-N10 as a source of radiation moves past the switch 
assembly in the direction of the arrow 336, for infrared radiation, 
represented by ray 335, in the sensing field N4 of the "look-out" field, 
for example, the radiation impinges on the planar mirror segment 72 which 
redirects the radiation as ray 335a onto the focusing mirror segment 91. 
The focusing mirror segment 91 focuses the radiation as ray 335b onto the 
sensor 41. 
With continued movement in the direction of arrow 336, the source of 
infrared radiation moves into sensing field N5, radiating ray 337 to the 
switch assembly which impinges on mirror segment 73 and is reflected as 
ray 337a to the focusing mirror segment 91. The focusing mirror segment 91 
focuses the radiation as ray 337b onto the sensor element 41. 
For the case where the infrared radiation is originating in the "look-down" 
field and is in any of the sensing fields D1-D10, the operation is 
similar. However, the incoming radiation incoming at 28.degree. 
(.+-.5.degree.) is directed by one of the reflective surfaces of mirror 
80b to the focusing mirror FIG. 16. 
Referring to FIGS. 4, 14 and 16, in all cases, the radiation is focused at 
the center line 41a of the sensor 41 to provide maximum signal output of 
the sensor 41. As the source of infrared radiation moves within range in 
the field N5 of the sensing field in the direction of arrow 337, the 
radiant infrared energy is initially focused at finger 106b of the sensor 
and sweeps along a generally straight line in the direction of the arrow 
337 from finger 106b to finger 106f. Dead zones occur when the rays are 
focused between adjacent pairs of the fingers 106b-106f of the sensor 
electrodes. 
When the focused energy reaches finger 106f, the direction reverses and 
with continued movement of the source of infrared radiation in the 
direction of arrow 338, the focused energy is directed to fingers 106e, 
106d, etc. 
When the source of radiation moves in the opposite direction, the focused 
energy is swept across the sensor in the reverse direction (arrow 338) 
from finger 106f to finger 106a. The size of the electrodes, which 
basically operate under a capacitive effect, defines the speed of response 
of the system to changes in movement within the sensing zones. 
Circuit Operation 
In operation, with reference to FIG. 18, it is assumed that the mode switch 
26 is operated to the AUTO position. As is apparent, when the mode switch 
is operated "OFF", the ground connection to the light bulb 16 is open and 
the light bulb cannot be energized. In the "ON" position ground is 
connected directly to one side of the light bulb, turning on the light. In 
the absence of infrared radiation, the field effect transistor 203 is 
maintained on, providing a short circuit around capacitor 206, preventing 
the triac 59 from being turned on. Thus, very little AC current flows from 
the hot conductor W through the lamp 16. As long as capacitor 206 is short 
circuited by field effect transistor 203, triggering of the triac 59 is 
prevented and very little current flows through the lamp 16. 
With reference to FIGS. 14, 17 and 18, when infrared radiation is directed 
to the sensor as the source of the infrared radiation moves relative to 
the sensing fields, the focus point of the radiation is swept along the 
sensor 41 from finger to finger of the electrode. As the focus point first 
approaches point Fl, the signal output of electrode 109 increases relative 
to that of electrode 111 resulting in an increase in the signal at the 
non-inverting input of amplifier 187. The output signal of amplifier 187 
responsively increases with continued movement of the source of radiation 
in the same direction, and approaches point F3. This results in a time 
varying signal which is coupled through capacitor 192 to the inverting 
input of amplifier 187a. Capacitor 193a and resistor 193 set the response 
time for amplifier 187a to the input signal to limit its response to 
signals varying at a rate greater than 60 Hz. 
The positive half cycles of signal output of amplifier 187a are applied 
through diode 194 to the inverting input of comparator 195 and the 
negative half cycles of the signal are applied through diode 194a to the 
non-inverting input of comparator 195. When this signal is less than Va or 
greater than Vb (less the drop across diode 194 or 194a), respectively, 
the reference voltages at the non-inverting and inverting inputs of the 
comparator 195, the comparator provides a negative going output. Such 
output is coupled through resistor 196 to the non-inverting input of 
comparator 197, resulting in a negative going signal at the output of 
comparator 197. When this signal is applied to the inverting input of 
comparator 201, the output provides a positive going output. This signal 
turns off the field effect transistor 203, interrupting the shorting 
circuit path around the capacitor 206. Accordingly, the capacitor 206 can 
now charge during each cycle of the AC signal raising the potential at 
point 207 to above the breakover voltage of the breakover device 205, the 
triac 59 is triggered on energizing the lamp 16 with full power. 
As long as the source of infrared radiation continues to move within the 
sensing field, the signal applied to the input stage 180 continues to 
vary, maintaining the drive stage enabled to keep the field effect 
transistor non-conducting. This enables the triac to be turned on each 
cycle to keep the lamp energized. 
When variations in infrared radiation cease to be detected by the sensor, 
the input stage will inhibit the comparator stage 181 causing its output 
to become logic high level. However, the charge on capacitor 217 maintains 
the potential at the inverting input of the output stage comparator 220 at 
a potential higher than the non-inverting input. The output of comparator 
220 is maintained at logic low level for the time duration, defined by the 
discharge time for capacitor 217, and inhibits all inputs to comparator 
stage 181. When the capacitor 217 discharges sufficiently, comparator 220 
switches its output to logic high level, enabling comparator stage 181 to 
detect additional infrared changes. 
The preceding operational description assumed that the photocell 28 was 
ineffective to inhibit circuit operation by virtue of the ambient light 
level being low enough to effect normal circuit operation or by virtue of 
the lens cover 28b being closed so as to prevent ambient light from being 
conducted to the photocell 28 via the light pipe 28a (FIG. 5A). For such 
conditions, the photocell, the resistance of which is proportional to 
applied light, maintains the dc voltage level at point 215 sufficiently 
low as to allow the signal output of comparator 220 to remain high to 
allow the above described operation of comparator stage 181. 
When the lens cover 28b is open, and/or the ambient light level is high, 
the photocell will conduct, lowering its resistance. This causes the 
voltage level at point 215 to increase switching the output of comparator 
220 low, inhibiting all outputs from comparator stage 181. 
Second Embodiment of Switch Assembly 
Referring to FIGS. 19-22, there is illustrated a second embodiment for a 
switch assembly 300 provided by the present invention. The switch assembly 
300 is particularly suitable for automatic outdoor light control and is 
adapted for mounting on the exterior of a house or other building for 
controlling the turning on and off of a light, such as a porch light, yard 
light, or the like as someone approaches the dwelling or building. 
As shown in FIGS. 19-22 the sensor switch assembly 300 includes a housing 
301 which contains a sensor assembly 302, and a mounting bracket 303 for 
pivotally mounting the housing on a vertical surface as illustrated in 
FIG. 22 which may be the exterior wall of a building or dwelling. In the 
embodiment shown in FIG. 22, the housing is pivoted forwardly and 
downwardly at an angle of approximately 8.degree. off normal, the angle 
inclination being adjustable. As shown in FIG. 21, a screw 304 permits 
loosening of the housing relative to the mounting bracket for adjustment 
of the angle of inclination. The switch assembly 300 includes a photocell 
assembly 305 shown in FIG. 19 which enables the light to be kept off 
during daylight hours. 
In principal, the switch assembly 300 operates, similar to switch assembly 
15, but because it is intended for mounting at a higher level, typically 
eight to ten feet above ground level, and to sense infrared radiation over 
larger field, the switch assembly 300 incorporates differences in its 
housing, optical system and sensor assembly as will become apparent. As 
will be shown, the switch assembly 300 defines two vertical fields of view 
including a shallow look-out field and a more vertical look-down zone 
shown in FIG. 22. Each of the look-out and look-down fields comprises 
eighteen zones each 10.degree. in arcuate width providing a 180.degree. 
field of view for the sensor in the look-out and look-down ranges as 
illustrated in FIG. 23. 
The switch assembly 300 senses infrared radiation over a 180.degree. range 
in horizontal planes. The sensing range includes two separate vertical 
fields of view, a shallow "look-out" field which extends downwardly at an 
angle e1 relative to the horizontal and a more vertical "look-down" field 
which extends downwardly at an angle fl relative to the horizontal. In one 
switch assembly which was constructed, the angles e1 and f1 were 8.degree. 
and 28.degree., respectively, providing semivertical angles of 82.degree. 
and 62.degree. for respective sensing fields. Each field in a vertical 
plane extends approximately 5.degree. on either side of a center lines 
represented by the dashed 307,307' lines for the "look-out" field and the 
"look-down" field, respectively. 
For the sensor used in an exemplary embodiment, the maximum sensing range 
for the switch assembly is on the order of 25 to 30 feet. When such a 
switch assembly is mounted at a height of eight feet, at the maximum limit 
of the sensing range, i.e. approximately twenty feet away from the place 
where the switch assembly is mounted, persons at least four feet tall will 
be detected. However, the maximum "look-down" field maximum range is 
approximately twelve feet at ground level from the location of the switch 
assembly for an angle e1 of 8.degree. . Thus, any person not detected 
within the "look-out" field will be detected within the "look-down" field 
if the person approaches to within twelve feet of the building. 
A person at least four feet tall entering the area encompassed by the 
twenty foot radius extending forward of the mounting location for the 
switch assembly 300 has to pass through the "look-out" field and would 
then cause the light bulb to be lit and remain lit for at least the 
duration of the delayed turn off period. Assuming that the person moves 
toward the location of the switch assembly, the person will pass out of 
the "look-out" field and pass through the "look-down" field, movements 
within either sensing field being detected by the switch assembly 300 to 
maintain the bulb lit. 
For the "look-down" field, there is a circular dead zone having a radius of 
approximately three feet measured from a point directly beneath the switch 
assembly. In other words, a person standing in that zone who is less than 
five feet tall would not be detected. However, a person located directly 
beneath the switch assembly would move into the sensing range from time to 
time, and such movements would be sensed by the switch assembly, enabling 
the bulb to remain lit. 
Referring to FIG. 23, the switch assembly 300 provides a 180.degree. 
"look-out" field having eighteen sensing zones B1-B18, each 10.degree. in 
arcuate length and a 180.degree. "look-down" field having eighteen sensing 
zones C1-C18 of approximately 5.degree. in angular extent. The 180.degree. 
sensing fields are in the shape of a half cone at a predetermined 
semivertical angle which for the look-out field is 82.degree. and for the 
look-down field is 62.degree.. Each sensing zone has an angular width of 
approximately 10.degree., and is, for example, approximately 36" wide at a 
distance of about twenty feet radially outward from the switching assembly 
which is located at the mid-point. The longer the range, the greater the 
arc and the wider the field of view will be. 
The eighteen sensing zones B1-B18 (and C1-C18), and the spaces between 
adjacent zones, such as space 308 between zones B1 and B2, space 308' 
between zones B2 and B3, etc., are determined by the configuration of the 
optical system and of the infrared sensor of the switch assembly as will 
be described. 
Switch Assembly 
Referring to FIG. 24, which illustrates the sensor assembly 302 and the 
housing 301, the housing 301 comprises a housing front 310 and a housing 
rear 311, the housing front 310 including a lens 312 behind which is 
mounted the sensor assembly 301. 
The sensor assembly 302 includes an optics shell 315 having an associated 
optics back plate 316, a printed circuit board 317, an infrared sensor 318 
and an electrostatic shield 319. 
Optics Shell 
Referring to FIGS. 25-28, the optics shell 315 is a generally rectangular 
open ended box like structure which defines the focusing mirror for the 
switch assembly 300. The optics shell 315 has a top wall 321, a bottom 
wall 322 and side walls 323 and 324. The side walls 323 and 324 extend 
inwardly from the rearward edge toward the forward or front wall of the 
optics shell 315. The forward surface 325 of the optics shell 315 
comprises an arcuate segment extending between the forward edges of the 
side walls 323 and 324, the forward portion terminating short of the upper 
wall 321 and terminating short of the lower wall 322 defining openings 331 
and 332, respectively. 
The inner rearward facing surface 326 of the forward wall defines a 
reflective surface of a stepped configuration including three reflecting 
segments 335, 336, and 337. The inner surfaces 338a of the side walls 323 
and 324 also define reflective surfaces. The optics shell is a one-piece 
molded unit of a rigid material such as Cyclolac ABS. The inner surface 
326 is coated with a reflective material, preferably aluminum, defining a 
focusing mirror comprising of segments 335-337 for the sensor assembly. 
The concave arcuate reflecting segments 335 and 337 focus on the sensor 
infrared radiation present in the look-out field and directed toward the 
top and bottom of the switch assembly, and concave arcuate segment 336 
focuses onto the sensor infrared radiation in the look-down field and 
directed toward the switch assembly. The reflecting segments 335-337 
define the 10.degree. vertical range for the sensing fields. 
The optics shell 315 further comprises a plurality of hook members 339 
extending outwardly and rearwardly from the side walls 323 and 324 for 
securing the optics shell 315 to the printed circuit board (FIG. 24) as 
will be shown. In addition, the upper and lower surface walls 321 and 322 
define alignment slots 340 which are provided for indexing and aligning 
the optics shell 315 with the optics back plate 316. 
The radii of the segments 335-337 in the horizontal plane vary with contour 
of the segments. The radius of curvature of segments 335 and 337 measured 
from a point 335R is 1.688 and the radius of curvature of segment 336 
measured from a point 336R is 1.541. A segment 326a in the form of a 
planar element extends upwards and forwardly between the end of segment 
337 and the lower end of segment 336 at an angle of 30.degree. relative to 
the horizontal. The side walls 323 and 324 diverge from front to rear of 
the optics shell at an angle of 15.degree.. 
Optics Back Plate 
Referring to FIGS. 29-34, the optics back plate 316 is a one-piece molded 
unit having a generally flat plate like portion with an outer frame 341 
with top and bottom members 342 and 343, respectively, and side members 
344 and 345. The back plate includes a first segmented planar mirror 350 
which extends horizontally along the upper portion of the frame 345, 
defining twelve segments or facets 350A-350L. The segments 350A-350L are 
generally elongated rectangular elements of the same size and inclined 
forwardly from top to bottom at an angle of 15.degree. relative to the 
vertical. As shown in FIG. 32, in the horizontal plane, the segments are 
oriented with their planar reflecting surfaces turned approximately 
15.degree. relative to a vertical plane extending through the forward 
surface of the mirror 50. Alternate segments 350A, 350C, 350E, etc., are 
oriented in one direction, such as to the left of the center line 351 of 
the optical assembly and the remaining elements 350B, 350D, etc. are 
oriented in the opposite direction to the right of the center line 351. 
Similarly, a second segmented planar mirror 360 is formed integral with the 
frame 345 at the bottom portion thereof. The mirror 360 includes twelve 
segments or facets 360A-360L, having a lower reflective portion with 
segments 360A'-360L' corresponding to segments 350A-350L, inclined 
inwardly at an angle of 15.degree. relative to the vertical and an upper 
portion with segments 360A"-360L" inclined at an angle of 5.degree. 
relative to the vertical. Segments 360A-360L are oriented 15.degree. 
relative to the vertical plane of the segmented mirror 360 in the manner 
of segments 350A-350L. The mirrors 350 and 360 correspond to mirrors 70 
and 80 (FIG. 8) of the switch assembly 15 and function in much the same 
manner. 
The twelve segments 350A-350L (and 360A'-360L') for the planar reflecting 
mirror 350 define the inner sensing zones B4-B15, the outer zones B1-B3 
and B16-B18 are defined by a compound planar reflecting system including 
the reflective inner surfaces 338 of inner side walls of the optics shell 
(FIG. 28) and the outermost segments 350A, 50B (360A', 360B') and 350K, 
350L (360K', 360L') for the look-out field. Similarly, reflective surfaces 
338 and segments 360A", 360B" and 360K" and 360L" define sensing zones 
C1-C3 and C15-C18 for the look-down field. This enables the switch 
assembly 300 to provide a 180.degree. range for the look-out and look-down 
sensing fields even though the optic assembly does not project beyond the 
forward surface of the housing in the assembled unit. 
The switch assembly 300 is intended for mounting high on a wall or other 
vertical surface, and may be located outside where it is subjected to the 
effects of weather. Thus, the optic assembly is contained within the 
housing and the optical shell assembly does not project through the 
forward surface of the housing. In addition, the reflecting mirrors 350 
and 360 are not oriented in convex fashion as are the segments of mirrors 
70 and 80 (FIG. 8). 
The optics back plate 316 is made of Cycolac ABS, for example, coated with 
a suitable reflecting material, such as aluminum, applied, for example, by 
vacuum metalization, to form the segments of the mirrors 350 and 360. 
An indexing tongue 368 projects upwardly from the top rail 342 and is 
received in the notch in the upper surface in the optics shell (FIG. 28). 
In addition, a pair of depending members 369 are received in the notches 
in the bottom side or lower side of the optics shell (FIG. 28). 
The portion of the back plate 316 between the upper mirror 350 and lower 
mirror 360 is open defining a window 370 through which the sensor 41 is 
exposed to view. 
Circuit Assembly 
The control circuit for the switch assembly 300 is generally the same as 
for switch assembly 15 (FIG. 1) and thus will be described in detail. The 
control circuit is carried on the printed circuit board 317 which is 
constructed and arranged to mount the optic assembly of optics shell 315 
on its forward surface and optics back plate 316. Referring to FIGS. 24 
and 42, to this end, the printed circuit board 317 includes a rectangular 
aperture 317a. 
The sensor 41 is secured to the rearward surface 317b overlying the 
aperture 317a and secured thereto in a suitable manner such as by use of a 
conductive adhesive. The optical assembly is mounted on the printed 
circuit board 317 overlying the aperture 317a such that the sensor 41 is 
located at the focal point of the focusing mirror. 
Referring to FIG. 24, the static shield 319 is bowed rearwardly to conform 
to the curved surface of the housing back 311 and to provide clearance at 
its center for the under surface of the printed circuit board 317 and 
sensor 41 mounted thereon. A ground contact finger 319b on the printed 
circuit board extends rearwardly thereof to engage the static shield 319 
in the assembled unit to connected ground for the control circuit to the 
static shield. 
The control circuit for the switch assembly 300 includes a photocell (not 
shown) and light lens assembly 310a mounted in the housing front 310 to 
conduct ambient light to photocell in the manner described above for light 
lens assembly 29 (FIG. 1) for switch assembly 15. It is apparent that 
light lens assembly 310a may not include a lens cover for applications 
where the switch assembly 300 is used outdoors. 
Switch assembly 300, may include a mode switch (not shown), adapted for 
mounting within the building with which the switch assembly is used. 
Housing Rear 
Referring to FIGS. 35-37, the housing rear 311 is an elongated, dish-shaped 
member having a curved back surface 381, generally rectangular upper and 
lower surfaces 382 and 383 and side walls 384 and 385 projecting forwardly 
from the rear wall 381. A plurality of indexing members 386-389 project 
forwardly from the inner surface of the back wall 381 which serve as 
alignment and mounting pins for the printed circuit board 317 (FIG. 24). 
As shown in FIG. 36, the pins 386-388 project beyond the plane of the 
upper edge of the housing rear 311. A plurality of stop members 391 
project forwardly from the rear wall near its upper and lower sides 382 
and 383 serving as stops or supports for the underside 317b of the printed 
circuit board 317 (FIG. 24). A pair of catches 392 are defined between 
pairs of projections 391 at the upper and lower edges of the housing rear 
311. 
A generally rectangular shaped bridge member 394 projects forwardly from 
the rear wall 381 defining a connector locator for locating the electrical 
conductors which supply electrical power to the switch assembly. The 
bridge member 394 has a rectangular slot 395 through its bottom portion, 
shown best in FIGS. 36 and 37. The bridge member overlies a rectangular 
opening 380 formed through the rear wall 381 of the housing rear 311. 
A generally cylindrical post 396 projects forwardly from the rear wall 381 
and has a central bore 396a therethrough which extends through the surface 
381 of the rear wall and is countersunk at 396a on the rear surface of the 
housing back as shown in FIG. 36. This opening permits insertion of an 
element for adjusting the turn off time delay for the control circuit of 
the switch assembly 300. 
The catches 392 are resilient elements, enabling them to be flexed 
outwardly by the side edges of the printed circuit board which engage the 
tapered forward surfaces of the catches as the printed circuit board is 
pressed onto the housing rear 311 during assembly of the unit. The catches 
392 can be flexed outwardly to release the printed circuit board for 
disassembly of the unit when necessary. 
Referring to FIGS. 35 and 36, the side walls 384 and 385 define 
semi-circular cutouts 399 and 399a which mate with semi-circular 
projections 404a and 405a (FIG. 24) on end walls 404 and 405 of the 
housing front 310. The forward peripheral edge 397 of the housing rear 311 
defines a ridge 397a. The housing rear 311 is preferably molded as a 
one-piece unit from a rigid material such as polystyrene. 
Housing Front 
Referring to FIGS. 38-41, the housing front 310 is generally 
semi-cylindrical in shape having a curved forward surface 401, generally 
rectangular top and bottom walls 402 and 403 and generally semi-circular 
end walls 404 and 405. The forward surface 401 has a rectangular cutout or 
aperture 406 in which is mounted the lens 312 (FIG. 24). The front surface 
401 has a further recessed portion 407 having an aperture 408 therethrough 
which passes the light pipe 310a (FIG. 24) to communicate light forward of 
the switch assembly housing to the photocell (not shown) mounted on the 
printed circuit board 317 (FIG. 24). 
Referring to FIGS. 39-41, a plurality of locating pins 410, which extend 
rearwardly from the housing front 310 near its peripheral edges, are 
located to be positioned for extending along the inner peripheral surface 
of the side walls of the housing rear 311. The peripheral edge 412 of the 
housing front 310 is cut back at its inner edge 414 for mating engagement 
with complementary peripheral edge 397 of the housing rear 311. 
One end wall 404 of the housing front 310 defines a semi-circular 
projection 416 which acts as a pivot and has formed thereon and projecting 
outwardly therefrom a short cylindrical member 418 which mounts a 
cylindrical shaped bearing surface formed in side arm 303a in the mounting 
bracket 303 and defining a pivot surface for rotation of the housing 
relative to the bracket. The other end wall 405 of the housing front 310 
has a reinforced section 418a including a semi-circular projection 420 
having a brass eyelet 422 mounted therein for receiving the set screw 304 
which provides the adjustable mounting for the housing relative to the 
mounting bracket 303. As shown in FIG. 41, a plurality of notches 424 are 
formed in the outer surface of the end wall 405 which are engaged by the 
inward projection or detent 426 on the mounting bracket 303 for locking it 
in place at the desired inclination. The housing front 310 is also made of 
polystyrene. 
In assembling the switch assembly 300, with reference to FIG. 24, the 
optics back plate 316 is assembled together with the optics shell 315, 
aligning the projections 368 and 369 with the slots 340 and 340a, 
respectively. The optics assembly is then mounted on the printed circuit 
board 317, aligning the hooks 339 with the apertures 339a in the printed 
circuit board. The optics assembly is then pressed onto the printed 
circuit board causing its hooks 339 to flex inwardly, allowing them to 
pass through the apertures 339a and to then spring back when they have 
cleared the printed circuit board, engaging the rearward surface of the 
printed circuit board 317. This secures the optics assembly to the printed 
circuit board 317. As has been indicated, the sensor 41 is affixed to the 
rearward surface of the printed circuit board 317 by a conductive adhesive 
which connects the conductors of the element to conductors (not shown) of 
the printed circuit board 317. 
The conductive shield 319 is positioned in the housing rear 311 with the 
connector inlet 394 passing through the aperture 319a. The assembled optic 
assembly and printed circuit board is then positioned in the housing rear 
311 with the index apertures aligned with the indexing posts 386-388 and, 
with the unapertured corner of the printed circuit board 317 resting on 
the rectangular indexing post 389. The printed circuit board 317 is then 
pressed into the housing back 311 causing the catches 392 to engage the 
forward surface of the printed circuit board, pressing the printed circuit 
board against stops 391 and 391a at opposite side walls of the cover 
housing rear 311. 
In assembling the housing front 310 on the housing rear 311, first the lens 
312 is positioned on the housing front extending through the opening 406 
with its flange 312a engaging the inner rearward surface of the housing 
front 310 around the periphery of the aperture 406. The housing front 310 
is then aligned with the housing rear 311 with the index member 408 
aligned with index notch 409 (FIG. 35) in the end wall of the housing rear 
311. The housing front and back are secured together in a suitable manner, 
such as by ultrasonic welding along the junction between the edges of the 
housing front 310 and housing rear 311. 
Referring to FIGS. 19-21, the thus assembled housing and sensor assembly is 
affixed to the mounting bracket 303 first inserting the annular bosses 
formed on the housing front 310 into respective recesses formed in the 
ends of the brackets. The housing is then adjusted to the desired angle, 
and the set screw 304 is tightened to bring the detent 426 into engagement 
with one of the notches 424 in the end wall of the housing, locking it in 
position. 
Operation of the Switch Assembly 
The manner in which the optical system of the switch assembly 300 focuses 
infrared radiant energy present in its detecting fields onto the sensor 41 
is described with reference to the simplified views of the switch assembly 
300 with the radiation patterns illustrated in FIGS. 43 and 44. 
It is assumed that a source of infrared radiation is moving toward the 
location of the switch assembly 300, first entering the look-out field, 
and moves toward the switch assembly eventually passing into the look-down 
field and passing out of the look-out field. 
Referring to FIGS. 22, 23 and 43, for the look-out sensing field, at or 
near the periphery of the 20 foot sensing field, infrared radiation, 
represented by rays 420 and 421, directed toward the switch assembly 300 
at an angle of 8.degree. (.+-.5.degree.) off the horizontal is received in 
sensing zones B7 and B8 for example, of the look-out sensing field, and 
passes through the openings 331 and 332 in the upper and lower portions of 
the housing front 310. Ray 420 is reflected off mirror 350 at an angle of 
46.degree. onto segment 335 of the focusing mirror which as ray 420a which 
focuses the radiation a ray 420b onto the sensor. The ray 421 impinging on 
mirror 360 at an angle of 8.degree. (.+-.5.degree.) off the horizontal at 
the bottom of the housing is reflected as ray 421a to segment 337 of the 
focusing mirror. The focusing mirror segment 337 focuses the radiation as 
ray 421b onto the sensor. 
In the near field range, say 10 feet away from the switch assembly, 
infrared radiation directed toward the switch assembly 300 at an angle of 
28.degree. (.+-.5.degree.) will be detected in the look-down field. In the 
look-down field, such infrared radiation represented by ray 426 will 
impinge on one of the segments 360A (depending on location within the 
180.degree. field) of the reflecting mirror and be reflected at an angle 
of 23.degree. (.+-.5.degree.)as ray 426a onto focusing mirror segment 336. 
Focusing mirror segment 336 will focus the radiation as ray 426b onto the 
sensor. 
With reference to FIG. 44, the manner in which the optical system of the 
switch assembly 300 receives infrared radiation in a generally horizontal 
field due to a person passing parallel to or in front of the switch 
assembly 300 in the near field range, is similar to that just described. 
However, the planar reflecting segments 360A-360L define two generally 
planar reflecting mirrors, one facing towards the left and the other 
towards the right of the center line of the unit. Thus, for a person 
passing the switch assembly 300 from the left of center in the direction 
of arrow 430 in FIG. 44, the radiation will impinge on segments 360B, 
360D, 360F, etc., whereas for a person moving to the right of center, the 
radiation will impinge on segments 360A, 360C, 360E, etc. 
Thus, assuming that a person is moving parallel to the switch assembly 300 
in direction of arrow 430 to the left of center, entering at zone C5, for 
example, and passing through zones C6 and C7 in succession, as the person 
moves into the sensing field, infrared radiation represented by ray 431 
will impinge on segment 360D and will be reflected to the focusing mirror 
segment 336. Focusing mirror segment 336 focuses the radiation as ray 431b 
onto the sensor 41. With continued movement of the person, infrared 
radiation represented as ray 432 will impinge on segment 360F" and be 
reflected as ray 432a to focusing mirror segment 336. The focusing mirror 
segment 336 will focus the radiation as ray 432b onto the sensor 41. 
The operation is similar for infrared radiation in the look-out field, the 
radiation being reflected by the segment 360. 
As described previously with reference to switch assembly 15, in all cases, 
the radiation is focused at the center of the sensor 41 to provide maximum 
signal output of the sensor. As a source of infrared radiation moves from 
sensing zone to sensing zone, the infrared energy is swept along a 
generally straight line along the sensor from finger to finger.