WO2007117333A2

WO2007117333A2 - Electroluminescent multi-pattern display in a night-light configuration

Info

Publication number: WO2007117333A2
Application number: PCT/US2007/000018
Authority: WO
Inventors: James Hillman
Original assignee: Impact Merchandising, Inc.
Priority date: 2006-01-03
Filing date: 2007-01-03
Publication date: 2007-10-18
Also published as: WO2007117333A3

Abstract

A night-light-style illumination device displays a pattern of changing lights utilizing a plurality of EL elements, and includes a housing that includes an electrical plug capable of engaging with a standard household AC power outlet. The EL driving circuit is coupled with a controller that causes the driving circuit to sequentially drive selected ones of the plurality of EL elements according to a first sequence. A low-cost circuit converts the AC power into power signals suitable for powering the controller and for driving the EL elements.

Description

ELECTROLUMINESCENT MULTI-PATTERN DISPLAY IN A NIGHT-LIGHT CONFIGURATION

FIELD OF THE INVENTION

[0001] The invention relates generally to illumination devices and, more particularly, to an electroluminescent night-light that is capable of displaying various light patterns.

BACKGROUND OF THE INVENTION

[0002] Electroluminescent lighting technology as applied in night-lights is well-known in the art. See, for example, U.S. Pat. Nos. 5,662,408, 5,779,346, 6,302,559, 6,337,541, and 6,905,231. in general, these devices include a housing, a plug for insertion into a household electrical outlet, and an electroluminescent (EL) element coupled to the plug terminals and positioned to emit light in the vicinity of the outlet based on energy supplied from the outlet. EL-type night-lights offer several advantages over traditional incandescent bulb-type night- lights, such as longer life, no maintenance (i.e. replacement of bulbs), substantially lower power consumption, lower operating temperature, and slimmer profile.

[0003] EL technology can also been used in a variety of novelty or indicia display devices, such as the ones described in U.S. Pat. Nos. 5,833,508 and 6,060,838. Display devices utilizing EL elements can take advantage of the inherent properties of the EL elements, including the ease with which the EL elements can be fabricated in a variety of useful or decorative shapes. One type of novelty display device that is known in the art includes a plurality of EL elements on a laminated display surface that are coupled, via flex circuitry, to control and driving circuitry adapted to energize different EL elements according to a selectable sequence. The control and driving circuitry is powered from replaceable battery cells located in a base to which the laminated display is electrically and mechanically attached.

[0004] When in use, an EL element emits visible light in response to an excitation signal.

A variety of compositions of EL material are known that can respond differently to a given type of excitation signal. For each particular EL material type, there generally an optimal excitation signal having a frequency and waveform that causes the EL material to produce the most light output per unit of energy dissipated. A typical optimal excitation signal has ah amplitude on the order of 100-200 Volts, and a frequency on the order of several kilohertz. VEL element driver circuitry is known in the art that is designed to provide an excitation signal having desirable characteristics. See, for example, U.S. Pat. No. 4,633,141, which describes a driving circuit that can convert a 5 V DC supply voltage into a 150 VAC, 3500 Hz excitation signal. • • • [0005] A principal design criterion in the development of consumer-oriented products is cost-efficiency. Designers of EL devices are almost always faced with the trade-off between low cost (i.e., minimal number of components) and high performance or energy efficiency, which is achievable with optimized electronic driving circuitry. Tn conventional AC mains-powered EL night-light devices, high-intensity light output is not needed. Therefore, in these devices, the EL elements are generally configured to be powered directly from the mains supply (e.g. 120 VAC, 60 Hz in North America), which provides an adequate, albeit sub-optimal, continuous light output. In these conventional low-cost designs in which the AC mains power is directly connected to the EL element (i.e. without intervening driving circuitry), automatic control of the light output or lighting pattern is impracticable.

[0006] In battery-powered EL display devices, there is inadequate voltage from the batteries for properly exciting the EL element, necessitating the inclusion of a relatively expensive electronic driving circuit for boosting the battery voltage to a level sufficient to excite the EL element to provide desired light output. The driving circuitry can, in turn, be optimized for the particular type of EL element being utilized for marginal additional cost. The availability of low voltage from the batteries enables the use of a conventional digital controller to individually control the EL elements. One drawback of such battery-powered devices is the need to replace or recharge the batteries that are consumed by operation of the devices. [0007] Conventional battery-powered EL display devices include an input for a low- voltage power supply that^" would effectively bypass the batteries. A conventional external AC- DC adapter that includes a step-down transformer, rectifier, and voltage regulator in a single package, can supply the necessary low-voltage power to run the battery-powered device from the AC mains. One drawback of such an arrangement is the need for the additional circuitry in the DC adapter to first down-convert the input power from AC mains supply to power the EL element driver and control circuitry (which require low voltage DC as input power), and then to step-up the low-voltage input power with the driving circuitry to a level sufficient to drive the EL element. The additional circuitry to reduce, and then to raise the voltage supply introduces undesirable size, weight, and cost constraints.

SUMMARY OF THE INVENTION

[0008] According to one aspect of the invention, a night-light display device includes an electrical plug adapted to interface electrically and mechanically with a household electrical outlet. The electrical plug includes a pair of terminals. The device includes a display that has a¹ plurality of electroluminescent (EL) elements decoratively arranged on at least one substrate. A circuit electrically couples the pair of terminals to the EL elements, and a housing mechanically couples the pair of terminals and the display and houses the circuit. The circuit includes a controller that causes selected ones of the EL elements to be sequentially illuminated according to a selected pattern. Additionally, a user input is electrically coupled to the controller, and facilitates user selection of the selected pattern from a set of preconfigured patterns. A power converter is electrically coupled with the pair of terminals and the EL elements, and operates to convert at least one of a line voltage and a line frequency present at the pair of terminals into a driving signal to be applied to the EL elements.

[0009] According to another aspect of the invention, a night-light-style illumination device includes a housing having a front cover and a front face, and a back cover and a back face that generally opposes the front face. At least a portion of the back face is integrally formed with the back cover, and the back face includes an electrical plug capable of engaging with a standard household AC power outlet. When the plug is engaged with the outlet, the back face is generally parallel with, and proximate to, a face of the outlet, and the back face has a shape and dimensions that define a wall footprint. At least a portion of the front face is integrally formed with the front cover. The front face includes a display having a plurality of EL elements, and the display has a shape and dimensions that are different from the wall footprint. The display displays a pattern of changing lights by sequentially illuminating different ones of the plurality of EL elements.

[0010] Another aspect of the invention is directed to merchandising a night-light display device that includes a plurality of separately-controllable electroluminescent (EL) elements and a user-operable selector control. A display rack is provided that presents a plurality of packaged night-light devices for retail sale. The display rack includes a household-style electrical outlet that supplies AC mains power. A demonstration night-light display device is permanently attached to at least one of the display rack and the electrical outlet. The demonstration night- light display device is electrically engaged with the electrical outlet. The demonstration night- light display device is operated such that: (a) the AC mains power is drawn from the electrical outlet and converted into a driving signal for the EL elements, the driving signal having a frequency that is different from a frequency of the AC mains; (b) the plurality of EL elements are sequentially illuminated according to a set of predetermined sequencing patterns that are selectable by operation of the selector control; and (c) in response to operation of the selector control, the plurality of EL elements are sequentially illuminated according to a different. sequencing pattern than a sequencing pattern according to which the EL elements were illuminated immediately prior to the operation of the selector control.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

[0012] FIG. 1 is an exploded-view diagram illustrating the construction of a night-light style display device according to one aspect of the invention.

[0013] FIGs. 2 and 3 are diagrams showing top, perspective, and cross-sectional views of housing portions of the night-light style display device of FIG. 1

[0014] FIG. 4 is a diagram illustrating a display portion of the night-light style display device of FIG. 1.

[0015] FIG. 5 is a block diagram illustrating functions of a low-cost circuit suitable for powering the night-light style display device of FIG. 1.

[0016] FIG. 6 is a circuit diagram illustrating a low-cost circuit suitable for powering the night-light style display device of FIG. 1..

[0017] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] According to one aspect of the invention, a decorative or novelty display device includes a plurality of electroluminescent (EL) elements, which can be controlled individually, or in groups. In one embodiment, the EL elements are shaped and positioned in a decorative pattern on a substrate or combination of substrates, which may also include printed graphics. The device further includes a controller that sequentially illuminates selected ones of the EL elements according to at least one pattern. In one embodiment, the device further includes a user input that facilitates user selection of a desired pattern from a set of preconfigured patterns. The mechanically with a household electrical outlet. The housing mechanically couples the plug to the plurality of EL elements, and the controller, and in one embodiment insulates high-voltage nodes for user safety.

[0019] According to another aspect of the invention, a decorative or novelty display device includes a low-cost circuit for controlling a sequence of selectively illuminating a plurality of controllable EL elements. The circuit accepts as its input an AC mains power supply, and provides a plurality of control signals corresponding to the plurality of controllable EL elements. The circuit also includes a digital controller adapted to .implement the sequence. When activated, each of the controllable EL elements receives a high-voltage excitation signal having a frequency that is higher than the frequency of the AC mains power supply. [0020] In one embodiment, the low-cost circuit includes a rectifier, a first voltage regulator that produces a relatively higher DC voltage, and a second voltage regulator that produces a relatively lower DC voltage. The first voltage regulator powers an oscillating sub- circuit that generates an oscillating voltage differential relative to the lower DC voltage. The lower DC voltage powers a controller sub-circuit that selectively sequences a set of illumination patterns to a plurality of EL elements via a multi-channel driver 'Circuit. The EL elements are respectively connected across corresponding channels of the driver circuit and the oscillating voltage such that the EL elements are powered substantially by the oscillating voltage differential.

[0021] According to a further aspect of the invention, a night-light-style illumination device displays a pattern of changing lights utilizing a plurality of EL elements, and includes a housing having a front cover and a front face, and a back cover and a back face that generally opposes the front face. At least a portion of the back face is integrally formed with the back cover. The back face includes an electrical plug capable of engaging with a standard household AC power outlet such that, when the plug is engaged with the outlet, the back face is generally parallel with, and proximate to, a face of the outlet, and the back face has a shape and dimensions that define a wall footprint. The front face includes a display having a plurality of EL elements. At least a portion of the front face is integrally formed with the front cover. The display has a shape and dimensions that are different from the wall footprint. In one embodiment, at least one major dimension of the display is larger than a corresponding dimension of the wall footprint. The housing houses an EL driving circuit that has an electrical power input coupled with the electrical plug, and a set of power outputs that is coupled with the plurality of the EL elements. Optionally, the EL driving circuit is coupled with a controller that causes the driving circuit to sequentially drive selected ones of the plurality of EL elements according to a first sequence.

[0022] FIG. 1 is an exploded-view diagram illustrating the main components of a night- light type electroluminescent (EL) display device 100 according to one embodiment of the invention. El display device 100 includes a back housing portion 102 that has slots 103 for accepting standard electrical plug blades 110. Plug blades 110 are fixed in place within back panel 107a, and are wired to power and control electronics 105 as depicted in FIG. 1. [0023] A front housing portion 104 fits together with back housing 104 to complete the housing for power and control electronics 105. Power and control electronics 105 are situated on, and interconnected via a printed circuit board (PCB) 106. In one embodiment, front housing portion 104 is connected with a light-emitting decorative display 107. In a related embodiment, a portion of decorative display 107 is formed together with front housing portion 104. Display 107 includes an opaque back panel 107a and an at least partially transparent front panel 107b. [0024] Between back panel 107a and front panel 107b are situated a plurality of EL elements. EL elements are generally known in the art. For example EL elements and the fabrication thereof are described in U.S. Pat. 6,922,020, which is incorporated herein by reference in its entirety. In one embodiment, the EL elements are fabricated onto a common substrate that has electrical conductors, such as copper traces, contacting the individual EL elements. In the embodiment depicted in FIG. 1, a flex circuit or ribbon cable 108 facilitates the electrical connection between the power and control electronics 105 and the substrate. In one embodiment, back panel 107a is the common substrate. In another embodiment, the common substrate (not shown) is separately fabricated and assembled onto back panel 107a and front panel 107b during assembly of device 100.

[0025] Tn one embodiment, as shown in FIG. 1 , device 100 includes a pushbutton 1 12, which is operable by the user to adjust the operation of device 100. Pushbutton 112 is positioned in the final assembly behind button cover 1 14, which can travel through port 115 in front panel 107b. Pushbutton 112 is wired to the power and control electronics 105 as depicted in FIG. 1. [0026] FIG. 2 depicts various views of front housing portion 104, which includes a front face 120. FIG. 3 depicts various views of back housing portion 102, which includes a back face 130. When front housing portion 104 and back housing portion 102 are assembled (FIG. 1), back face 130 and front face 120 are mutually opposing. When plug blades 110 of device 100 are engaged with a standard household electrical outlet, back face 130 of back cover portion 102 is generally situated against the face of the outlet. Back face 130 may or may not be in intimate contact with the outlet face, but back face 130 is generally parallel with the outlet face and is situated proximate to the outlet face when device 100 is plugged into the outlet. Back face 130 has major dimensions u and v. When device 100 is plugged into the outlet, back face 130 defines a wall footprint 132 of device 100 having dimensions u and v.

[0027] FIG. 4 illustrates one embodiment of display 107. Display 107 has a decorative shape having major dimensions x and y. In one embodiment, at least one of major dimensions x and y are larger than the corresponding major dimensions u and v (FIG. 3) of wall footprint 132. Thus, in this embodiment, dimension x is greater than dimension u (FIG. 3) and/or dimension y is greater than dimension v (FIG. 3). The large, or over-sized, dimension of display 107 relative to wall footprint 132 facilitates the use of a larger display area without occupying an equivalently large wall footprint.

[0028] Display 107 includes a substrate 138 upon which are situated a plurality of EL elements indicated at 140, 142, 144, 146, 148, and 150. Each EL element has a pair of electrical connections for interconnection between a driving signal supply and ground. As depicted in FIG. 4, each EL element has an electrical path to a common ground conductor 152. The type of electrical path can be different for various EL elements. For example, EL element 140 has a direct connection common ground conductor 152, while EL element 148 has an indirect path to ground conductor 152 that includes EL element 144. Thus, EL elements 148 and 144 are series- connected.

[0029] The electrical interconnection between each EL element and the driving signal supply can similarly include a variety of types of electrical paths. As depicted in FIG. 4, EL elements 140, 142, 146, and 150 each have a direct connection via conductors 141, 143, 147, and 151, respectively, to their driving signal supply (not shown). Series EL element 148 is connected directly to its driving signal supply via conductor 151, while series EL element 144 is connected to the driving signal supply of EL element 148. Conductor 149 completes the circuit for series elements 144 and 148.

[0030] In a preferred embodiment, conductors 141, 143, 145, 147, 151, and 152 are formed as traces on substrate 138, and continue as wires bundled together in ribbon cable 108. A connector 154 maintains electrical contact between the traces on substrate 138 and the wires of ribbon cable 108. At the opposite end of ribbon cable 108 is a connector that maintains electrical contact between each wire of ribbon cable 108 and the traces of PCB 106 on which the driving and control circuitry is arranged. [0031] FIG. 5 is a block diagram illustrating the functional components of a driving and control circuit 500 according to one embodiment. Circuit 500 receives its power from AC mains 502, which are standardized in the U.S. at 110-120 VAC, 60 Hz, via plug input 504. The AC power is converted to a high-voltage DC power signal 506 by rectifier and filter 508. A first low-cost voltage regulator 510 reduces high-voltage DC power signal 506 to a medium- voltage DC power signal 512. From medium-voltage DC power signal 512, a second low-cost voltage regulator 514 produces low- voltage DC power signal 516.

[0032] Low- voltage power signal 516 powers controller 518, which controls the sequencing of illuminating the EL elements 520a-520g, collectively referred to herein as EL elements 520. Controller 518 includes controller logic that can be implemented in a variety of forms, such as in hardware logic, in software logic, or in a combination thereof such as in a dynamically self-reprogrammable hardware logic array.

[0033] • Each of EL elements 520 in FIG. 5 represents a group of at least one EL element that is separately-controllable from the remaining EL elements 520. Thus, for example, EL element 520a can represent a group of 1, 2, or more EL elements that are series- or parallel- connected. In this embodiment, controller 518 is not able to drive RL elements 520. Therefore, EL driver 522 interfaces controller 518 with the EL elements 520. EL driver 522 receives control signaling 524 from controller 518, and converts control signaling 524 into a plurality of driving signals 526a-526g, collectively referred to herein as driving signals 526. Each of driving signals 526 corresponds to a dedicated EL element 520.

[0034] Control signaling 524 can be in a variety of forms. In one embodiment, control signaling 524 is a set of independent signals, each corresponding to a separate EL element 520 to be driven. Tn another embodiment, control signaling 524 is a multiplexed signal, such as by code division or time division, that conveys the equivalent control information as separate dedicated control lines. In a related embodiments, control signaling 524 can be a digital multi-bit signal requiring separate parallel lines, or a serialized digital signal. Control signaling 524 can be binary signaling (i.e. representing a single amplitude at any given time), or can represent multiple amplitudes, either digitally, or in the analog domain.

[0035] In the embodiment depicted in FIG. 5, EL driver 524 receives a single driving signal supply 528, which EL driver selectively applies to EL elements 520 according to control signaling 524 to produce driving signals 526. In one embodiment, driving signal supply 528 has an amplitude and frequency that is matched with the EL technology of the EL elements 520 to produce a light output of the maximum brightness desired. In one embodiment, EL driver 524 is capable of independently adjusting or modulating driving signal supply 528 when produce each driving signal 526. In this embodiment, EL driver 524 can thus regulate the light output of the EL elements 520.

[0036] Driving signal supply 528 is generated from medium-voltage DC power signal

512 by the combination of oscillator 530, amplifier 532, and amplitude booster 534. Oscillator 530 is powered by medium-voltage DC power signal 512, and generates a high-frequency input 536 to amplifier 532. In turn, amplifier 532, also powered by medium-voltage DC power signal 512, drives amplitude booster 534 with an amplified high-frequency signal 538 to produce EL driving signal supply 528. In one embodiment, oscillator 530 and amplifier 532 are combined in a single sub-circuit using resonant positive feedback to produce only amplified high-frequency signal 538.

[0037] In operation, driving and control circuit 500 illuminates various combinations of

EL elements 520 according to a selectable pattern. User interface 540 facilitates selection of the sequence by the user. In one embodiment, user interface 540 is a pushbutton interfaced with controller 518. The logic of controller 518 responds to the press of the pushbutton by changing to the next sequential pattern.

[0038] Table 1 below illustrates one example of a selectable sequence of patterns. The

Selectable Sequence ID column represents different sequences of EL element illumination patterns. In the embodiment in which user interface 540 is a single pushbutton that facilitates selection of a particular sequence by cycling through a set of available sequences, the Selectable Sequence ID can represent the number of button presses since power-up of the device needed to select the corresponding sequence.

[0039] Under the Time heading, each time duration T1-T4 represents the duration during which the EL elements 520 are maintained in the corresponding states. For each time duration T1-T4, there is a particular pattern of illumination of EL elements 520. In this example, for the sake of simplicity, the EL elements are either "ON" or "OFF," and are not illuminated at varying intensity. However, persons skilled in the art will appreciate that the basic concept of this example can be expanded to cover a virtually limitless set of combinations and permutations of illumination patterns. Under each column heading corresponding to each EL element 520, a "1" represents that the EL element is illuminated, while a "0" represents that it is off. [0040] For simplicity, the time durations T1-T4 have been limited to four, and the actual length of time of each duration has been left ambiguous. Persons skilled in the art will appreciate that there can be a more time durations (in excess of four) and that the length of each time duration can be different. For each sequence ID, the EL elements are illuminated according to the sequence of patterns shown for the corresponding time durations T1-T4. After T4, the selected sequence can either repeat, switch to a different sequence ID, or stop.

Table 1

[0041] In one example embodiment, certain EL elements are cycled according to one or more optionally selectable patterns, while other EL elements are maintained in a constant ON or OFF state. This type of arrangement is illustrated in Table 1 above, in which Selectable Sequence ID 0 includes EL element 520g staying OON while the remaining elements are cycled; and in which Selectable Sequence ID 1 includes EL element 520g staying OFF while the remaining elements are cycled.

[0042] FIG. 6 illustrates an electrical circuit schematic of a driver and controller circuit

600 according to one embodiment. Input power is received across power inputs indicated at AC 120V. Rl, Cl, and RT provide power input filtering and transient suppression, respectively. Rectifier ridge BRl converts AC power from the input into a unidirectional current flow. R3, C2, and ZOl respectfully filter the unidirectional current into a direct current (DC) power signal, and regulate the voltage according to the breakdown characteristic of ZOl. A second, lower, DC power source is achieved by the combination of R6, C3. and Z02. The voltage at the cathode of ZOl is a relatively higher regulated DC power source, whereas the cathode of Z02 is a relatively lower DC voltage power source.

[0043] Integrated circuit Ul contains control logic for sequencing the EL elements (not shown) through the various illumination patters. Ul receives its input signaling according to switch SWl, which is operated by a user. Ul outputs a set of 5 control signals, respectfully via R7-R11, and each output signal drives the base of a corresponding output driver transistor Ql- Q5. The emitters of each of Q1-Q5 are commonly tied to the low voltage DC source at the cathode of Z02. The collectors of each of Q1-Q5 are each connected to a respective individually-controllable set of EL elements via connector Jl. Driver transistors Q1-Q5 are operated in one embodiment as switching elements. In another embodiment, driver transistors Q1-Q5 are operated in their active mode (or, in the case of FETs, in their pinched channel mode). Optionally, selective dimming of the EL elements may be achieved by either embodiment, such as, for example, by duty cycling the switch mode transistors for the first embodiment, or by dissipating energy in the transistors for the latter embodiment. [0044] The circuit through each of the EL elements is completed to a common node indicated at ELCOM. The voltage at ELCOM is an alternating voltage signal of a relatively high frequency that establishes a cyclically oscillating voltage differential relative to the low-voltage DC supply at the cathode of ZOl. The oscillating signal at ELCOM is achieved by the circuit consisting of Q6, R4-R5, and C4-C5, as well as transformer Tl . Q6 operates as an oscillator/amplifier that switchably drives the primary of Tl . Tl is wound to magnify the voltage at its primary to produce a relatively higher voltage for ELCOM.

[0045] Circuit 600 produces an optimized set of driving signals for a plurality of EL elements having a relatively high voltage and high frequency. Controller Ul provides a set of pattern sequences for a decorative EL display. The power management components facilitate powering circuit 600 from ordinary household AC mains power. This overall functionality of circuit 600 is achieved at a substantially low cost with a small number of simple, readily- available electrical and electronic components.

[0046] According to one aspect of the invention, device 100 is marketed in a retail scenario in a special display configuration that facilitates demonstration of its functionality. According to one embodiment, the display configuration includes a household-style outlet positioned prominently on a display rack. The display rack holds packages of a plurality of devices such as device 100 that ore being offered for sale. A functional demonstration unit of device 100 is engaged with the household-style outlet on the display rack for power to be supplied to the demonstration unit. Also, the demonstration unit is permanently (i.e., non- removably) attached to the outlet or to the display rack for durability of the display configuration and to prevent the demonstration unit from being stolen.

[0047] In one embodiment, the user-operable control (such as pushbutton 112) is exposed for operation by shoppers. Signage or other indicia drawing shoppers' attention to the pushbutton is included on the display rack near the demonstration unit.

[0048] The invention may be embodied in other specific forms without departing from the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, with the invention being limited only by the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A night-light display device comprising: an electrical plug adapted to interface electrically and mechanically with a household electrical outlet, the electrical plug including a pair of terminals; a display including a plurality of electroluminescent (EL) elements that are decoratively arranged on at least one substrate; a circuit that electrically couples the pair of terminals to the EL elements; a housing that mechanically couples the pair of terminals and the display and houses the circuit; wherein the circuit includes: a controller that causes selected ones of the EL elements to be sequentially illuminated according to a selected pattern; a user input electrically coupled to the controller, wherein the user input facilitates user selection of the selected pattern from a set of preconfigured patterns; and a power converter electrically coupled with the pair of terminals and the EL elements, wherein the power converter operates to convert at least one of a line voltage and a line frequency present at the pair of terminals into a driving signal to be applied to the EL elements.

2. The night-light display device of claim 1, wherein the circuit further comprises a set of driver transistors electrically coupled to the controller, the EL elements, and the power converter.

3. The night-light display device of claim 1, wherein the user input comprises a pushbutton switch.

4. The night-light display device of claim 1, wherein the set of preconfigured patterns includes patterns in which a certain at least one EL element remains in an illuminated state while at least one other EL element is sequenced through illuminated and non-illuminated states.

5. The night-light display device of claim 1, wherein controller provides an output that includes a plurality of control signals, wherein each control signal corresponds to a set of at least one individually controllable group of at least one EL element.

6. The night-light display device of claim 1, wherein the power converter provides a high- voltage excitation signal having a frequency that is higher than a frequency of an AC mains power supply to which the pair of terminals is connected via the household electrical outlet.

7. The night-light display device of claim 1, wherein the circuit includes a rectifier, a first voltage regulator that produces a relatively higher DC voltage, and a second voltage regulator that produces a relatively lower DC voltage; wherein the first voltage regulator powers an oscillating sub-circuit that generates an oscillating voltage differential relative to the lower DC voltage; wherein the lower DC voltage powers a controller sub-circuit that selectively sequences a set of illumination patterns to a plurality of EL elements via a multi-channel driver circuit; and wherein the EL elements are respectively connected across corresponding channels of the driver circuit and the oscillating voltage such that the EL elements are powered substantially by the oscillating voltage differential.

8. A night-light-style illumination device comprising: a housing having a front cover and a front face, and a back cover and a back face that generally opposes the front face; wherein at least a portion of the back face is integrally formed with the back cover, and the back face includes an electrical plug capable of engaging with a standard household AC power outlet such that, when the plug is engaged with the outlet, the back face is generally parallel with, and proximate to, a face of the outlet, and the back face has a shape and dimensions that define a wall footprint; wherein at least a portion of the front face is integrally formed with the front cover; wherein the front face includes a display having a plurality of EL elements, and the display has a shape and dimensions that are different from the wall footprint; and wherein the display displays a pattern of changing lights by sequentially illuminating different ones of the plurality of EL elements.

9. The night-light-style illumination device of claim 8, wherein at least one major dimension of the display is larger than a corresponding dimension of the wall footprint.

10. The night-light-style illumination device of claim 8, wherein the housing houses an EL driving circuit that has an electrical power input coupled with the electrical plug; and a set of power outputs that is coupled with the plurality of the EL elements.

11. The night-light-style illumination device of claim 10, further comprising a controller coupled with the EL driving circuit, wherein the controller is programmed to cause the driving circuit to drive certain ones of the plurality of EL elements according to a first sequence and according to a second sequence that is different from the first sequence.

12. The night-light-style illumination device of claim 11, further comprising a user-operable input device coupled with the controller, wherein the controller is programmed to respond to operation of the user-operable input device by changing from driving the EL elements according to the first sequence to driving the EL elements according to the second sequence.

13. A method of merchandising a night-light display device that includes a plurality of separately-controllable electroluminescent (EL) elements and a user-operable selector control, the method comprising: providing a display rack that presents a plurality of packaged night-light devices for retail sale, wherein the display rack includes a household-style electrical outlet that supplies AC mains power; permanently attaching a demonstration night-light display device to at least one of the display rack and the electrical outlet; electrically engaging the demonstration night-light display device with the electrical outlet; operating the demonstration night-light display device such that: the AC mains power is drawn from the electrical outlet and converted into a driving signal for the EL elements, the driving signal having a frequency that is different from a frequency of the AC mains; the plurality of EL elements are sequentially illuminated according to a set of predetermined sequencing patterns that are selectable by operation of the selector control; and in response to operation of the selector control, the plurality of EL elements are sequentially illuminated according to a different sequencing pattern than a sequencing pattern according to which the EL elements were illuminated immediately prior to the operation of the selector control.