Assembly for visually indicating signals generated by an electrical circuit and light-diffusing interface apparatus therefor

An assembly for visually indicating signals generated by an electrical circuit and a light diffuser therefor. Light emitting diodes disposed upon a circuit board and housed within a housing structure are connected to an electrical circuit and generate light responsive to signals generated by the electrical circuit. A sheet of translucent material having a spine-portion and toothed-portion extending therefrom is positioned upon the circuit board portion at which the light emitting diodes are disposed. Light diffusers comprised of truncated, conical bodies protrude beyond top surfaces of each of the toothed-portions and correspond in number and spacing with the light emitting diodes disposed upon the circuit board. Apertures are formed to extend through the housing assembly and top end portions of the light diffusers are visible from beyond the housing assembly. The light diffusers diffuse the light generated by the light emitting diodes to form a uniformly-lighted indication of times in which such diodes are lighted.

BACKGROUND OF THE INVENTION 
The present invention relates generally to light diffusers and, more 
particularly, to a light-diffusing interface apparatus for diffusing light 
generated by a light-generative device. 
A communication system is operative to transmit information between two or 
more locations, and includes, at a minimum, a transmitter and a receiver 
interconnected by a communication channel. In a radio communication 
system, the communication channel comprises a radio frequency channel 
wherein a radio frequency channel is defined by a range of frequencies of 
the communication spectrum. Information is transmitted by the transmitter 
to the receiver by transmitting the information upon the radio frequency 
channel to the receiver. 
The transmitter which forms a portion of the radio communication system 
includes circuitry for converting the information into a form suitable for 
transmission thereof upon a radio frequency channel. Such circuitry 
includes modulation circuitry which performs a process referred to as 
modulation. In such modulation process, the information which is to be 
transmitted is impressed upon a radio frequency electromagnetic wave, 
commonly referred to as a carrier signal. The resultant signal, formed of 
a combination of the carrier signal and the information, is commonly 
referred to as a modulated signal. Such resultant signal is also referred 
to as a communication signal as the modulated signal includes the 
information which is to be communicated by the transmitter to the 
receiver. 
Various types of modulation schemes have been devised for impressing the 
information upon the carrier signal, thereby to form the communication 
signal. For instance, amplitude modulation, frequency modulation, phase 
modulation, and combinations of such modulation schemes are all modulation 
schemes by which the information may be impressed upon the carrier wave to 
form the communication signal. 
Radio communication systems are advantageous in that no physical 
interconnection is required between the transmitter and the receiver; once 
the information is modulated to form a modulated signal, a modulated 
signal may be transmitted over large distances. 
Numerous modulated signals may be simultaneously transmitted upon different 
radio frequency channels defined upon the electromagnetic frequency 
spectrum. Transmission of modulated signals on different ones of the radio 
frequency channels defined upon certain frequency bands of the 
electromagnetic frequency spectrum is regulated by regulatory bodies. 
A two-way, radio communication system is a radio communication system, 
similar to the radio communication system above-described, but which 
further permits both transmission and reception of information at first 
and second, spaced-apart locations. Each location of a two-way radio 
communication system contains both a transmitter and a receiver. The 
transmitter and the receiver positioned at a single location typically 
comprise a unit referred to as a radio transceiver, or, more simply, a 
transceiver. A transceiver capable of alternate operation either to 
transmit or to receive a communication signal is referred to as being 
capable of simplex operation. A transceiver capable of simultaneous 
operation both to transmit and to receive a communication signal is 
referred to as being capable of duplex operation. 
A cellular communication system is one type of two-way radio communication 
system in which communication is permitted with a radio transceiver 
positioned at any location within a geographic area encompassed by the 
cellular communication system. 
A cellular communication system is created by positioning a plurality of 
fixed-site radio transceivers referred to as base stations, at 
spaced-apart locations throughout the geographic area. The base stations 
are connected to a conventional, wireline, telephonic network. Each base 
station has associated therewith a portion of the geographic area located 
proximate to each of such base stations. Such portions are referred to as 
cells. The plurality of cells, each defined by corresponding ones of the 
base stations of the plurality of base stations together define the 
coverage area of the cellular communication system. 
A radio transceiver, referred to in the cellular communication system as a 
radiotelephone, positioned within any location within the coverage area of 
the cellular communication system is able to communicate with a user of 
the conventional, wireline, telephonic network by way of a base station. 
Modulated signals are transmitted between the radiotelephone and the base 
station to effectuate communication therebetween. 
Typically, the radiotelephone includes a handset assembly operative in a 
manner analogous to the operation of a handset assembly of conventional 
telephonic apparatus. 
In some radiotelephone constructions, only portions of the circuitry of the 
radiotelephone is disposed within the handset assembly, In such 
constructions, the handset assembly is coupled to transceiver circuitry 
housed within other structure. In other radiotelephone constructions, the 
entire circuitry of the radiotelephone is housed within the handset 
assembly thereof. 
In either type of radiotelephone construction, however, the handset 
assembly includes structure to facilitate operation of the radiotelephone. 
As such structure typically requires the interaction of a user, such 
structure is typically referred to as a user interface. 
For instance, the handset assembly of either type of radiotelephone 
includes a user interface which permits the user to effectuate telephonic 
communication by way of the radiotelephone with a remote site. Such user 
interface typically comprises a telephonic keypad to permit the user to 
enter a desired call sequence (i.e., a telephone number) thereby to 
effectuate telephonic communication with a location associated with such 
call sequence. 
Additionally, information is provided by the radiotelephone to indicate to 
the user of such radiotelephone certain parameters of operation of such 
radiotelephone. Typically, such information is provided in the form of a 
visual indication by light-generative devices, usually light emitting 
diodes. 
Light emitting diodes are advantageously utilized to provide the 
indications to the user of the parameters of operation of the 
radiotelephone as the light emitting diodes are operable at low power 
levels. Use of such light emitting diodes is particularly advantageous 
when the radiotelephone is powered by a portable power source. 
Diodes generate a nondiffuse light pattern. Because of this characteristic, 
many designs of radiotelephone constructions position the diodes near the 
surface of the housing of the handset assembly, thereby to ensure that the 
light generated by such diodes is noticeable to the user of the 
radiotelephone. 
Radiotelephones are oftentimes operated in darkened conditions. To 
facilitate operation of such radiotelephones in the darkened conditions, 
the keypad supported by the handset assembly oftentimes also includes 
light-generative devices, once again typically formed of light emitting 
diodes, for illuminating the keypad display. 
In some radiotelephone constructions, the keypad display is comprised of a 
thermoelastic, and also translucent, material. The thermoelastic and 
translucent material may, for example, be comprised of a silicone 
rubber-type material. The light emitting diodes forming the 
light-generative devices which illuminate the keypad display are 
positioned beneath individual actuation switches of the keypad display. 
The translucent keypad acts to diffuse the point-intensive light pattern 
of the light generated by the light emitting diodes. When the diodes are 
lighted, the diffusion of the light caused by the keypad display causes 
the entire keypad display to be illuminated. 
Positioning of a similar such translucent material upon the light emitting 
diodes utilized to indicate the certain parameters of operation of the 
radiotelephone to the user thereof would also be advantageous to the user. 
However, such additional piece of translucent material increases the 
piece-part count of the radiotelephone. The increased piece-part count 
increases not only the product part cost of the radiotelephone, but also 
increases the number of assembly steps required to assemble such 
radiotelephone. 
When more than one proximately-positioned light emitting diode (or other 
light generative device) are separately lighted by the circuitry of the 
radiotelephone to provide indications of different parameters of operation 
of the radiotelephone, confusion as to which of the light emitting diodes 
is lighted can occur. Transmission of the light generated by the 
proximately-positioned diodes through the translucent material resulting 
in confusion as to which of the diodes (or other light-generative devices) 
is lighted is undesirable. Such undesired transmission is sometimes 
referred to as light bleed. Light bleed resulting in confusion as to which 
of more than one proximately-positioned diodes is lighted should be 
minimized. 
What is needed is a light-diffusing interface apparatus for diffusing light 
generated by light-generative devices for an electronic device which does 
not increase the product part count of the electronic device and which 
minimizes light bleed between adjacently-positioned light-generative 
devices. 
SUMMARY OF THE INVENTION 
The present invention, accordingly, advantageously provides a 
light-diffusing interface apparatus for diffusing light generated by a 
light generative device. 
The present invention further advantageously provides an assembly for 
visually indicating signals generated by an electrical circuit. 
The present invention yet further advantageously provides an interface 
apparatus for a radio transceiver. 
The present invention contains further advantages and features, the details 
of which will become more apparent when reading the following detailed 
description of the preferred embodiments. 
In accordance with the present invention, therefore, an assembly for 
visually indicating signals generated by an electrical circuit is 
disclosed. The assembly comprises at least two light-generative devices 
coupled to the electrical circuit wherein a first light-generative device 
of the at least two light-generative devices is operative to turn-on when 
a first of the signals is generated by the electrical circuit. A second 
light-generative device of the light-generative devices is spaced apart 
from the first of the light-generative devices and is operative to turn-on 
when a second of the signals is generated by the electrical circuit. A 
sheet of translucent material is positioned above both the first and 
second light-generative devices, respectively, of the at least two 
light-generative devices. At least two spaced-apart light diffusers formed 
of the translucent material comprising the sheet of translucent material 
is positioned to extend beyond a top surface of the sheet of the 
translucent material. A first light diffuser and a second light diffuser 
of the at least two light diffusers are spaced-apart by distances 
corresponding to distances at which the first and second light-generative 
devices, respectively, are spaced-apart, thereby to permit alignment of 
the first light diffuser with the first light-generative device and 
alignment of the second light diffuser with the second light-generative 
device. Light emitted by the first and second light-generative devices, 
respectively, are diffused by corresponding ones of the first and second 
light diffusers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
At the outset, it should be noted that, while the assembly of the preferred 
embodiment of the present invention is described in connection with a 
radio transceiver such as a radiotelephone operative in a cellular 
communication system, the teachings of the present invention are similarly 
applicable for use in other devices and other applications. 
Turning first, then, to the exploded, cutaway view of FIG. 1, the assembly, 
referred to generally by reference numeral 100, of a preferred embodiment 
of the present invention is shown. Assembly 100 is operative to indicate 
visually signals generated by an electrical circuit. Here, the electrical 
circuit is represented by block 106, shown in hatch, which is disposed 
primarily upon a bottom surface of circuit board 112. 
Electrical circuit 106 generates signals on lines 118 (here five lines 118 
are shown) which lead to light-generative devices 124. In the preferred 
embodiment of the present invention, light-generative devices 124 are 
comprised of light emitting diodes. 
Circuit board 112 of FIG. 1 is further shown to include an array of input 
terminals 134 at which input signals are applied, thereafter to be 
supplied to electrical circuit 106 by way of lines 140. As illustrated, 
input terminals 134 are arranged in rows and columns to form an array of 
terminals. Additional light-generative devices 146 are further disposed 
upon circuit board 112. Light-generative devices 146 are also preferably 
comprised of light emitting diodes and are also connected to electrical 
circuit 106 by electrically-conductive lines (not shown in the figure). 
Keypad interface 150 is positioned above a top face surface of circuit 
board 112 and is of dimensions permitting tandem positioning of a face 
surface of keypad interface 150 upon the top face surface of circuit board 
112. Keypad interface 150 includes a plurality of keypad push buttons 156 
arranged in rows and columns to form an array of keypad pushbuttons. 
Individual ones of the keypad pushbuttons 156 are spaced-apart by 
distances corresponding to distances at which input terminals 134 are 
spaced-apart upon the top face surface of circuit board 112. 
Keypad interface 150 is comprised of a flexible, thermoelastic material and 
is constructed to permit limited vertical translation of individual ones 
of the keypad pushbuttons 156. In the preferred embodiment, keypad 
interface 150 is comprised of a silicone rubber-type material. The 
thermoelastic material comprising keypad interface 150 is preferably 
translucent and is both light-diffusive and light-transmissive. (Keypad 
pushbuttons 156, also comprised of the silicone rubber-type material are 
similarly both light-diffusive and light-transmissive.) 
An electrically-conductive material is coated upon bottom portions (not 
shown in FIG. 1) of the keypad pushbuttons 156. When a bottom face surface 
of keypad interface 150 is aligned with circuit board 112 and is 
positioned upon the front face surface of circuit board 112, individual 
ones of the keypad pushbuttons 156 of the array of pushbuttons 156 are 
aligned with corresponding ones of the input terminals 134 of the array of 
input terminals 134. 
Keypad pushbuttons 156 are actuated by application of a downward 
translation force upon face surfaces of individual ones of keypad 
pushbuttons 156. Translation of keypad pushbuttons 156 responsive to 
application of such actuation force thereto causes the bottom portions of 
such keypad pushbuttons 156, coated with the electrically-conductive 
material, to abut against input terminals 134. Such abutment of the 
electrically-conductive coating upon adjoining input terminals 134 closes 
contacts comprising each of the terminals 134 and thereby form the input 
signals applied to electrical circuit 106. 
Keypad pushbuttons 156 are arranged in a configuration corresponding to the 
configuration of a conventional, telephonic keypad and are operative to 
permit manual entry of a desired call sequence corresponding to a 
telephone number to be entered by a user. 
Sheet 170 is formed integral with keypad interface 150 to extend beyond a 
top edge surface thereof. Sheet 170 is comprised of the same thermoelastic 
material of which keypad interface 150 is comprised. Again, in the 
preferred embodiment, sheet 170, integrally formed with keypad interface 
150, is comprised of the silicone rubber-type material. The thermoelastic 
material comprising sheet 170 is also translucent to be both light 
transmissive and light-diffusive thereby. Sheet 170 is of like a comb-like 
configuration forming a spine-portion 176 with toothed-portions 182 
extending therefrom. In the embodiment of FIG. 1, five toothed-portions 
extend beyond spine-portion 176. Adjacent ones of the tooth-portions 182 
are spaced-apart from each other to define thereby gaps 188 therebetween. 
Light diffusers 194 are formed to extend beyond a top face surface of each 
tooth-portion 182 of sheet 170 and are comprised of the same material as 
that of sheet 170 and keypad interface 150. As illustrated, light 
diffusers 194 are conically-shaped and have truncated top ends. Each light 
diffuser 194 forms a truncated conical body thereby. While diffusers 194 
are integrally formed with sheet 170, the diffusers are formed to be of 
thicknesses less than the thickness of sheet 170 (and also keypad 
interface 150) thereby to be more greatly light-transmissive (and less 
light-diffusive) than sheet 170 (and keypad interface 150). 
Individual ones of the toothed-portions 182 are spaced apart by distances 
such that when keypad interface 150 is positioned in tandem with the top 
face surface of circuit board 112 to align keypad pushbuttons 156 with 
corresponding input terminals 134, light diffusers 194 formed upon the 
individual ones of the toothed-portions 182 align with individual ones of 
the light-generative devices 124. Once positioned as such, light emitted 
by individual ones of the light-generative devices 124 pass through a 
corresponding light diffuser 194 positioned thereabove. 
As light diffusers 194 are operative to diffuse the light directed thereat, 
light generated by individual ones of the light generative devices 124 is 
diffused by a light diffuser 194 positioned thereabove, and the entire 
surface area of the particular one of the light diffusers 194 positioned 
over top the particular light-generative device 124 is illuminated. 
Because gaps 188 are formed between adjacent ones of toothed-portions 182, 
light generated by any particular ones of the light-generative devices 124 
is transmitted through only the toothed-portion 182 and the associated 
light diffuser 194 positioned thereabove; such light is not transmitted to 
an adjacent one of the toothed-portions 182. 
Unwanted transmission of light resulting in the aforementioned light bleed 
of light generated by any particular one of the light-generative devices 
124 is thereby minimized as only insignificant amounts of light are 
transmitted across the separate boundaries of the translucent, 
thermoelastic material comprising sheet 170 and the toothed-portions 182 
comprising portions thereof. It should be noted that, as noted 
hereinabove, because the thicknesses of diffusers 194 are less than the 
thickness of sheet 170, diffusers 194 are more light transmissive than 
sheet 170, light diffusers 194 appear to channel and to focus the light 
generated by light generative devices positioned therebeneath. 
Transversely-extending channel 198 formed proximate to the intersection 
between keypad interface 150 and sheet 170 extends across a substantial 
portion of the distance between opposing side surfaces of keypad interface 
150 and sheet 170. While not shown in the view of FIG. 1, a similar such 
channel (spaced somewhat apart from that of channel 198) is formed to 
extend transversely along a bottom side of the structure proximate to the 
intersection of keypad interface 150 and sheet 170. 
Such channels are operative to minimize undesired transmission of light 
(i.e., light bleed) through the thermoelastic material comprising 
interface 150 and sheet 170 of light generated by either any of the 
light-generative devices 124 or light-generative devices 146. 
Turning next to the cutaway view of FIG. 2, a portion of handset assembly 
200 is shown in exploded form. Assembly 100 of FIG. 1 forms a portion of 
handset assembly 220. Accordingly, commonly-numbered circuit board 112, 
keypad interface 150 and sheet 170 extending from a top edge surface 
thereof form portions of handset assembly 200. 
The view of FIG. 2 illustrates the face surface of circuit board 112 hidden 
from view in FIG. 1 upon which substantial portions of electrical circuit 
106 are disposed as well as lines 118 which extend to light-generative 
devices 124. 
Keypad interface 150 is again shown to include keypad pushbuttons 156 which 
are arranged to form an array of pushbuttons 156. And, the plurality of 
toothed-portions 182 and light diffusers 194 are also again shown in the 
figure. The view of FIG. 2 further illustrates transversely-extending 
channel 199 which forms the channel, noted briefly hereinabove, which is 
substantially similar to that of channel 198 shown FIG. 1. 
Handset assembly 200 is further shown to include handset housing portions 
216 and 222. Handset housing portions 216 and 222 are of dimensions 
permitting supportive housing therewithin of, inter alia, circuit board 
112, keypad interface 150, and sheet 170. 
An inner wall 228 of handset housing portion 222 is further illustrated in 
the view of the figure. A plurality of spaced-apart, 
longitudinally-extending rib members 234 are formed upon inner wall 228. 
Rib members 234 are spaced-apart by distances corresponding to the widths 
of toothed-portions 182 of sheet 170 (and, hence, also to the distances 
separating gaps 188 formed at opposing sides of toothed-portions 182). 
Such spacing of rib members 234 thereby permits interfitting engagement of 
such rib members 234 with toothed-portions 182 when such toothed-portions 
182 are suitably aligned therewith. Rib members 234 are operative thereby 
to support toothed-portions 182 in position. Also, as rib members 234 are 
comprised of an opaque material, the rib members are operative to prevent 
undesired transmission of light (i.e., light bleed) generated by 
light-generative devices 124 once circuit board 112 and keypad interface 
150 are tandemly positioned and toothed-portions 182 and rib members 234 
are positioned in the interfitting engagement therebetween. 
Apertures 240 are formed to extend through handset housing portion 222 at 
locations between adjacent ones of the rib members 234. Apertures 240 
extend the entire distances between inner wall 228 of housing portion 222 
and a corresponding outer wall of the housing portion. Apertures 240 are 
of diameters permitting insertion therein of portions of light diffusers 
194. Apertures 240 are thereby operative to support light diffusers 194 in 
position once toothed-portions 182 are positioned in the interfitting 
engagement with rib members 234. 
By suitable selection of the dimensions of handset housing portion 222 as 
well as the heights of light diffusers 194, the top edge surfaces of the 
truncated, conical bodies forming light diffusers 194 may be positioned 
flush with an outer wall of handset housing portion 222 once the light 
diffusers 194 are positioned to extend into apertures 240. Because light 
diffusers 194 are operative to diffuse the light generated by 
light-generative devices 124, a uniformly-lighted circular area 
corresponding to the top edge surface of a light diffuser 194 appears at 
the outer wall of handset housing portion 222 when a light-generative 
device 124 is lighted. Because of gaps 182 positioned between adjacent 
toothed-portions 182, opaque rib members 234, and channels 198 and 199, 
light bleed of light transmitted through the translucent material 
comprising sheet 170 and light diffusers 194 is insignificant. 
Turning next to FIG. 3, a radiotelephone, referred to generally to 
reference numeral 300, of a preferred embodiment of the present invention 
is shown in partial-perspective, partial-block form. Radiotelephone 300 
includes commonly-numbered, housing assembly 200 shown in the exploded 
view of FIG. 2 as a portion thereof. Housing assembly 200 is again shown 
to be comprised of handset housing portions 216 and 222. Circuit board 
112, keypad interface 150, and sheet 170 are supported within assembly 
200. 
Radiotelephone 300 further includes radio transceiver circuit 312 which is 
coupled to the circuitry, including circuit board 112, housed within 
handset assembly 200. It should be noted that, while radio transceiver 
circuitry 312 is illustrated in the figure as being located separate from 
handset assembly 200, radio transceiver circuitry 312 may also alternately 
be housed entirely within handset assembly 200. In such an embodiment, 
radiotelephone 300 forms a portable radiotelephone. 
Outer wall 328 of handset housing portion 222, hidden from view in the view 
of FIG. 2, is illustrated in the perspective view of FIG. 3. Keypad 
pushbuttons 156 extend through openings formed to extend through handset 
housing portion 222 to be accessible by a user of radiotelephone 300. A 
user may utilize such keypad pushbuttons 156 to enter a call sequence 
corresponding to a telephone number by application of actuation forces 
upon individual ones of the keypad pushbuttons 156. 
Apertures 240 and top end portions of light diffusers 194 are further 
illustrated in the perspective view of radiotelephone 300 of FIG. 3. Light 
generated by individual ones of the light-generative devices 124 shown in 
the preceding figures is diffused by a light diffuser 194 positioned 
thereupon, as described previously, thereby to provide a uniformly-lighted 
indication at the circular, top-end portion of the associated light 
diffuser 194 visible from the exterior of handset assembly 200. Because 
light bleed is insignificant, a mistaken indication of lighting of one or 
another of the light-generative devices is obviated. 
Because sheet 170 is integrally formed with keypad interface 150, use of 
the light diffusers disposed thereupon is permitted while not increasing 
the product part count of radiotelephone 300. (Rib numbers 234 are also 
integrally formed with handset housing portion 222 and similarly do not 
increase the product part count of radiotelephone 300.) Accordingly, 
assembly of radiotelephone 300 including such light diffusers 194 is 
permitted without any increase in assembly complexity. 
Finally turning now to the cross-sectional view of FIG. 4, a sectional view 
of a portion of handset assembly 200 taken along lines IV--IV of FIG. 3 is 
shown. The relationship between a single light-generative device 124 and a 
single light diffuser 194 is shown. Light generated by light-generative 
device 124 is diffused by light diffuser 194. As light diffuser 194 is 
inserted to extend into an aperture 240 extending through handset housing 
portion 222, only a top, end portion of light diffuser 194 is visible from 
beyond the handset assembly 200. 
Top surface 350 of light diffuser 194 is positioned beneath lens 360 and is 
spaced apart therefrom by a slight distance for aesthetic reasons. 
(Positioning of top surface 350 is abutting engagement with a surface of 
lens 360 can result in an aesthetically displeasing appearance referred to 
as a "water effect.") 
The thickness of top surface 350 is somewhat greater than sidewalls of 
diffuser 194 thereby to increase the amount of diffusion of light directed 
thereat by light-generative device 124 and may be of any desired thickness 
to cause a desired amount of light diffusion of light generated thereat. 
While the present invention has been described in connection with the 
preferred embodiments of the various figures, it is to be understood that 
other similar embodiments may be made and modifications and additions may 
be made to the described embodiments for performing the same functions of 
the present invention without deviating therefrom. Therefore, the present 
invention should not be limited to any single embodiment, but rather 
construed in breadth and scope in accordance with the recitation of the 
appended claims.