WO2022101371A1

WO2022101371A1 - Assembly and method for uniform illumination of icons on a housing of a power device

Info

Publication number: WO2022101371A1
Application number: PCT/EP2021/081450
Authority: WO
Inventors: Le Gia Pham; Nathan Farrell
Original assignee: Koninklijke Philips N.V.
Priority date: 2020-11-13
Filing date: 2021-11-12
Publication date: 2022-05-19

Abstract

A handle assembly (10) and method for uniform illumination of an icon on a housing (14) of a power device (12) wherein a primary printed circuit board (36) and a secondary printed circuit board (38) are operatively coupled via a connector (42). One or more secondary light sources (44) are mounted on the secondary printed circuit board (38). One or more secondary light pipes (46) with several shielding methods are coupled to the one or more secondary light sources (44) to illuminate the icon such that the one or more secondary light sources (44) provide uniform illumination of the icons on the housing.

Description

ASSEMBLY AND METHOD FOR UNIFORM ILLUMINATION OF ICONS ON A HOUSING OF A POWER DEVICE

FIELD OF THE INVENTION

[0001] The present disclosure is directed generally to an assembly and method for uniform illumination of icons on a housing of a power device.

BACKGROUND

[0002] Many power devices, such as electric toothbrushes, have handles with icons visible on an external surface of the handle for improved user experience. Icons are often lit up by light emitted diodes (LEDs) mounted on a main printed circuit board (PCB) assembly. For purposes of controlling light brightness and light patterns, light pipes which are mounted over the LEDs on the main PCB assembly, can be used.

[0003] The main PCB assembly is structured to the core main frame assembly of the device which is disposed in the housing of the electric toothbrush. During product assembly the core main frame and main PCB assembly are put in place in the handle by inserting the entire assembly into the handle. The main PCB assembly and the icons on the handle are positioned to allow light from the LEDs to light up the icons. This can be aided by light pipes that are mounted between the LEDs and icons. However, any structural components that are present between the LED or output end of the light pipe and the icon display on the handle will interfere with the optical path of light emitted by the LEDs and any icons whereof the light path is obstructed cannot be lit.

SUMMARY

[0004] It is desirable to improve assemblies and methods that provide uniform illumination of icons on a handle of a power device. [0005] According to aspects and embodiments described herein addressing such a need, the present disclosure is directed to an assembly and method for lighting up icons on a power device wherein the light path from the main PCB may be obstructed by internal assembly components, such as a connector. In some embodiments, a combination of light pipes and light baffles can provide for uniform illumination of the icons.

[0006] In some embodiments, a handle assembly for a power device may include a housing configured to be held in a hand of a user. The handle assembly may have one or more user interface elements including at least one illuminable icon configured to be visible on an outer surface of the housing. The handle assembly further includes a primary printed circuit board arranged within the housing, a secondary printed circuit board arranged within the housing and abutting an inner surface of the housing. The secondary printed circuit board may be operatively coupled to the primary printed circuit board via a connector. One or more secondary light sources may be mounted on the secondary printed circuit board. One or more secondary light pipes may be configured to convey light from the one or more secondary light sources on the secondary printed circuit board to the at least one illuminable icon and to provide uniform illumination of the at least one illuminable icon.

[0007] In other implementations, the present disclosure is related to a method for uniform illumination of an icon on a housing of a power device. The method includes the steps of providing a primary printed circuit board within the housing, providing a secondary printed circuit board within the housing abutting an inner surface of the housing, operatively coupling the secondary printed circuit board to the primary printed circuit board via a connector, mounting one or more secondary light sources on the secondary printed circuit board, and coupling one or more secondary light pipes to the one or more secondary light sources to illuminate the icon such that the one or more secondary light sources provide uniform illumination of the icons on the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the inventive subject matter.

[0009] FIG. 1 is a perspective view of a handle of an electric toothbrush illustrating schematically an embodiment of a handle assembly according to the inventive subject matter.

[0010] FIG. 2 is a partial cross-sectional view of the assembly of FIG. 1.

[0011] FIG. 3 is a cross-sectional view of a detail of FIG. 2.

[0012] FIG. 4 is a top perspective view of a light pipe as used in the handle assembly shown in FIG. 2.

[0013] FIG. 5 is a bottom perspective view of the light pipe shown in FIG. 4.

[0014] FIG. 6 is a partial cross-sectional view of a detail of the handle assembly of FIG. 1 illustrating operation of the light pipe.

[0015] FIG. 7 is a top perspective view of another embodiment of a light pipe including a light shielding part.

[0016] FIG. 8 is a top perspective view of another embodiment of a light shielding part.

[0017] FIG. 9 is a bottom perspective view of the light shielding part shown in FIG. 7.

[0018] FIG. 10 is a perspective view of light pipe provided with the light shielding part shown in FIGS. 7 and 8.

[0019] FIG. 11 is a top perspective view of another embodiment of a light shielding part.

[0020] FIG. 12 is a bottom perspective view of the light shielding part shown in FIG. 10.

[0021] FIG. 13 is a perspective view of a light baffle as used in the handle assembly of FIG. 2.

[0022] FIG. 14 is a partial cross-sectional view of the handle assembly of FIG. 2 illustrating operation of the light baffle.

DETAILED DESCRIPTION OF EMBODIMENTS

[0023] The disclosed subject matter will become better understood through review of the following detailed description in conjunction with the figures. The detailed description and figures provide example embodiments of the invention described herein. Those skilled in the art will understand that the disclosed examples may be varied, modified, and altered without departing from the scope of the invention described herein.

[0024] In some power devices, such as electric toothbrushes, multiple icons can provide a user interface display on an external surface of the handle. Some handles include faceplates, seamless buttons, or other components with portions that are at least partially transparent to allow light from internal light sources to pass through thereby illuminating the icons. As used herein, an icon refers to a graphical element such as a symbol, word, or other image, displayed on the housing of the power device allowing a user to easily select a desired function or to provide a user with information.

[0025] Seamless buttons with force gage sensors, or similar types of sensors, can be used to improve the user experience. Such sensors, however, require the sensors and their components to be mounted on the inside of the handle housing wall, for example opposite to the externally marked icons, in order to receive a press force input from a user. The sensors and their associated components can be mounted on a printed circuit board that is different from the main PCB so that they are held in place while facing an inside wall of the handle housing. For example, in the embodiments described below some of the sensors and their associated components are coupled to a secondary printed circuit board disposed right up against an inner surface of the housing.

[0026] For intercommunication between the boards, the secondary PCB may be connected to the main or primary PCB via a connector, such as a flexible ribbon cable. In some locations, this connector may block the optical path to the icons of light emitted by the LEDs and light pipes on the main PCB. As a result, the affected icons cannot be lit and cannot be seen by users. In those instances wherein user interface elements and light sources are located on a secondary printed circuit board assembly mounted on the back of the inner wall of the handle, and wherein the illuminable icons are long or large, the icons may benefit from being illuminated by a LED coupled to a light baffle on the main PCB assembly.

[0027] In addition, for commercial purposes and advantages in cost and development time, a product family often has multiple product versions with a diversity in user interface layout, for example using different icons and buttons, and/or different housing design but may share the same core structure.

[0028] In view of the foregoing, various embodiments and implementations are directed to an assembly and method for uniform illumination of icons on a housing of a power device wherein a direct optical light path between LEDs and icon may be obstructed. It is noted that particular features, structures, or characteristics of one or more embodiments discussed below may be combined in any suitable manner to form new, not explicitly described embodiments.

[0029] In some embodiments, a combination of optical coupling elements can be arranged to bypass any obstacles and to uniformly illuminate icons on the handle of the power device. For example, multiple icons on the external surface of the housing of the handle of a power device can be lit up via a combination of one or more light pipes. The light pipes can be mounted on a secondary PCB assembly hosting the sensors. Additionally, a light baffle can be mounted on the main PCB assembly in an area of the internal assembly that does not interfere with a connector between the main PCB and secondary PCB.

[0030] FIG. 1 illustrates an embodiment of a handle assembly 10 for an electrical toothbrush 12 wherein icons can be illuminated uniformly by using a combination of optical coupling elements. Handle assembly 10 includes a housing 14 having an elongated tubular shape configured to be held in a hand of a user. Housing 14 has a top portion 16 adapted to be coupled to an oral care implement, such as a brush head or other dental appliance. Housing 14 has a cavity 22 wherein the internal components of electric toothbrush 12 are encased, and a bottom portion 18 is closed off with a bottom cap 20.

[0031] An outer surface 24 of housing 12 can include a display of user interface elements 26 which can have illuminated portions and non-illuminated portions. For example, indicator lights may be used to communicate a status of the device to the user and buttons may be used for user interaction.

[0032] Some user interface elements 26 may be provided with an icon or symbol to indicate the function of the user interface element. Some icons can be lit up at outer surface 24 of housing 12. The embodiment shown in FIG. 1 includes a power icon 27, three intensity dot icons 28a, 28b, and 28c, a text icon 30, a brush head icon 32 and a battery icon 34. The icons can be applied to the housing, for example by laser etching on a housing made of plastic or other sufficiently hard or durable material.

[0033] FIG. 2 shows details of some of the internal components of handle assembly 10. The internal assembly includes a primary PCB 36 arranged within housing 12. A secondary PCB 38 may also be arranged within housing 12 and may abut an inner surface 40 of housing 12 such that user interface elements 26 can be coupled to secondary PCB 38. A force gauge sensor 48 (indicated in FIGs. 2 and 8) is disposed in proximity of text icon 30 and intensity dot icons 28a, 28b, and 28c such that users can change a mode of the toothbrush by pushing the icons. Furthermore, a force gage sensor may be associated with power icon 27 allowing a user to turn the toothbrush on or off.

[0034] Secondary PCB 38 can be operatively coupled to primary PCB 36 via a connector, such as a flat flexible interconnect cable 42. As can be seen on the left side of FIG. 2, flexible interconnect cable 42 may be folded between secondary PCB 38 and primary PCB 36 in an S-shaped configuration. In other embodiments, the connector can be any assembly that includes one or more power and/or data conductors allowing power transfer connections, data transfer connections and/or signal transfer connections between a primary PCB and secondary PCB.

[0035] Secondary light sources, such as LEDs 44a and 44b, can be mounted on secondary PCB 42 to illuminate certain icons. A secondary light pipe 46 may be mounted on secondary PCB 38 positioned above flexible interconnect cable 42, as can be seen in FIG. 3, and coupled to LEDs 44a and 44b. Secondary light guide 46 can be made of a substantially translucent material, such as an acrylic plastic, polycarbonate, epoxies, glass, and other suitable materials. Secondary light pipe 46 may be configured to convey light from secondary light sources 44a and 44b to icons 32 and 34. To illuminate the icons and to bypass any possible interference of flexible cable 42 on the way, light pipe 46 can be provided with input ends positioned near secondary light sources 44a and 44b and output ends terminating at the light-emitting areas near icons 32 and 34 respectively. Light pipe 46 may be secured to secondary light sources 44 on secondary PCB 38, for example via instant glue or epoxy or pressure sensitive adhesive tape or other suitable means. In other embodiments, icons can be illuminated with secondary light sources mounted on the secondary PCB coupled to light pipes providing a different configuration of optical paths. [0036] In some embodiments, light pipe 46 may include a brush head light pipe 56 for illuminating brush head icon 32 and a battery icon light pipe 58 for illuminating battery icon 34. To effectively transmit light emitted by LEDs 44a and 44b to icons 32 and 34, secondary light pipe 46 can be configured to conform to the requirements of the user interface element while also reducing or minimizing the light bleed. To prevent the inadvertent capture of light from the wrong lit up light pipe, secondary light pipe 46 can be provided with a wedge-shaped part that fits between the light emitting surfaces.

[0037] FIG. 4-5 illustrate an embodiment wherein secondary light pipe 46 includes a connecting member in the form of a general rectangularly shaped frame 76 with wedge-shaped portions to connect two light pipes 58 and 56. Brush head light pipe 56 may have a serrated portion 60 on a slanted surface 62 and battery light pipe 64 may have a serrated portion 66 on a slanted surface 66 which together are configured to redirect the light path emitted by LEDs 44a and 44b to icons 32 and 34 respectively while avoiding bleeding into an adjacent light pipe and distributing the light rays as uniform as possible on the exit surfaces of light pipes 56 and 58. LED 44b may be disposed in an opening in frame 76 between serrated portion 60 and serrated portion 66.

[0038] Secondary light pipe 46 may further include serrated side portions 68, 70 on two opposite side bars 72 and 74 respectively of secondary light pipe frame 76. Serrated portions 68, 70 are configured to minimize side light bleed, i.e., where light from one turned-on light pipe can travel along the side bars to light up the other light pipe unintentionally, and thereby prevent light from bleeding from one light pipe to the other light pipe which could also provide the user with a false reading.

[0039] To effectively illuminate battery icon 34 and to reduce light bleeding from LED 44b back to light pipe 56 and brush head icon 32, frame 76 may include a sloped surface, such as chamfer 78, on a top surface of frame 76 between the two light pipes. A light beam generated by LED 44b may move along the chamfer surface 78 and can be redirected vertically where it can be absorbed by the black shield tape. Inside light pipe 58, light beams can be redirected by chamfer surface 78 to illuminate battery icon 34.

[0040] To secure secondary light pipe 46 to secondary PCB 38, secondary light pipe frame 76 may include locating features or docking elements, as can be seen in FIG. 5. For example, protrusions 80a and 80b can be positioned on a surface of light pipe frame 76 opposite of the side of the frame having serrated surfaces. Protrusions 80a, 80b ensure that secondary light pipe 46 fits cut-outs on secondary PCB 38 to securely position secondary light pipe 46 on secondary PCB 38 and to maintain a consistent gap with the LEDs, thereby preventing that light pipe 46 sits flat on secondary PCB 38. As secondary light pipe 46 is glued to secondary PCB 38, its position can vary upon the actual clearance between the light pipe and holes cut in secondary PCB 38. [0041] To prevent light from bleeding from one light pipe into another light pipe, light-blocking tape may be applied between the two light pipes. For example, as shown in FIG. 3, light shielding tape 54, such as black tape, can be mounted on a surface of secondary light pipe 46 to prevent cross light bleed between brush head light pipe 56 and battery icon light pipe 58.

[0042] FIG. 6 illustrates the principle of operation of secondary light pipe 46, discussed above with reference to FIGs. 4-5. When LED 44a of brush head icon 32 is turned on, a light beam LI will travel through brush head light pipe 56 and reflect to brushead icon 32 at serrated portion 60. A portion of light, indicated by L2, may refract past serrated portion 60 and possibly bounce inside the handle and bleed the battery light pipe 58, or directly enter the battery light pipe 58, as indicated by L3. Black shield tape 54, indicated in dashed line in FIG. 6, applied on light pipe 46 will absorb light L2 and prevent light from bouncing back and bleeding into battery light pipe 58. Chamfer 78 may help redirect the undesired coming light L3 to black shield tape 54 to minimize bleed.

[0043] In some embodiments, light bleeding in the light pipes can be prevented by providing a light pipe frame with a two-shot or over-molded light shielding part, made of a light shielding material. For example, as illustrated in FIG. 7, a light pipe 146 includes a light pipe frame 176 made of a clear plastic material and an over-molded barrier 154 made of black rubber. Barrier 154 can be applied between light pipes 156, 158 and side bars 172, 174 to prevent light from bleeding between light pipes 156 and 158.

[0044] FIGS. 8-10 show another embodiment wherein light bleeding between light pipes is prevented by coupling light pipe 246 to a distinct light shielding part 254. Light shielding part 254 can be shaped and dimensioned to fit within the internal opening of the frame between light pipes 256 and 258 and over the LED. Light shielding part 254 is substantially rectangular shape to cover the LED disposed in the frame and includes two legs adapted to fit around the sides of light pipe 256 such that light shielding member 254 sits flush with the adjoining frame. Light shieling part 254 can be glued down, for example with black tape, to the secondary PCB.

[0045] FIGS. 11-12 show yet another embodiment of a light shielding part 354. Light shielding part 354 is dimensioned and shaped to be complementary to the contours of the light pipe and is positioned such that it encapsulates the entire light pipe. To prevent light bleeding, light shielding part 354 can be made of a black rubber material. A separator portion 378, protruding from a main body 380 of light shielding part 354, may prevent light from bleeding between the two slanted surfaces of the light pipes.

[0046] Returning to FIGs. 1 and 2, some icons, such as intensity icons 28a, 28b, 28c and text icon 30, on housing 12 can be illuminated with primary light sources 50, such as LEDs 50a, 50b, 50c, mounted on primary PCB 36. For these icons, light pipes and/or light baffles, may be used to illuminate icons vertically. Especially larger icons, such as text icon 30, where these icons are not obstructed by the flexible interconnect cable may benefit from this type of illuminations as a broader light pattern can be created from LEDs further away. To effectively illuminate icons with primary light sources mounted on primary PCB 36, a light baffle can be used.

[0047] FIG. 13 illustrates details of an embodiment of a light baffle 82 that can be mounted on primary PCB 36. Light baffle 82 has an an elongated configuration adapted to selectively block light emitted by the LEDs on primary PCB 36 and to allow illumination of text icon 30 and three intensity dot icons 28a, 28b, 28c. Light baffle 82 may have two locating holes 84a and 84b to secure baffle 82 on primary PCB 36, and may further have two slots 86a, 86b adapted to hook to snaps (not shown) on primary PCB 36. Three open slots 88a, 88b, 88c can be provided for housing the three LEDs of the intensity dot icons 28a, 28b, 28c. In one embodiment, light baffle 82 can be an overmolded part forming a black body frame 90 adapted to fit over a portion of the primary PCB assembly. Light baffle 82 may be provided with optical grade translucent parts 92a, 92b, 92c. The optical grade translucent part is on top of each LED assigned for each intensity icon. To prevent light bleeding between intensity icons, another light shield 94 may be mounted on secondary PCB 38. [0048] FIG. 14 illustrates the principle of operation of light baffle 82. As discussed above, light baffle 82 may be designed for three possible mode icons but as shown in FIG. 13 only the first mode icon is lit. When LED 50d is activated, light will shine up, diffuse past top translucent portion 92c, and uniformly light up to mode icon 30 directly above. Similary for the intensity dot icons, when LEDs 50a, 50b, 50c are activiated, light is shining up to respective intensity dot icons 28a, 28b, 28c but is prevented from bleeding into the closely adjacent icons thanks to the light shield 94.

[0049] In some embodiments, larger icons, such as text icon 30, shown in FIG. 1, may use multiple LEDs to be completely and uniformly illuminated. In other possible embodiments, where user interface and design requirments are simpler, a button with one or two icons and a single printed circuit board mounted on the handle housing may be effective without a need for an additional printed circuit board assembly and light baffle.

[0050] In another aspect, the inventive subject matter contemplates a method for uniform illumination of an icon on a housing of a power device. The method includes providing a primary PCB within the housing, providing a secondary PCB within the housing abutting an inner surface of the housing, operatively coupling the secondary PCB to the primary PCB via a connector, mounting one or more secondary light sources on the secondary PCB, coupling one or more secondary light pipes to the one or more secondary light sources to illuminate the icon, thereby bypassing the connector, such that the one or more secondary light sources provide uniform illumination of the icons on the housing.

[0051] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

[0052] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0053] The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, /.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified.

[0054] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" or "and/or" shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be interpreted as indicating exclusive alternatives (i.e. "one or the other but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of."

[0055] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified.

[0056] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0057] In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

[0058] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0059] Applicant(s) reserves the right to submit claims directed to combinations and subcombinations of the disclosed inventions that are believed to be novel and non-obvious. Inventions embodied in other combinations and sub-combinations of features, functions, elements and/or properties may be claimed through amendment of those claims or presentation of new claims in the present application or in a related application. Such amended or new claims, whether they are directed to the same invention or a different invention and whether they are different, broader, narrower or equal in scope to the original claims, are to be considered within the subject matter of the inventions described herein.

Claims

What is claimed is:

1. A handle assembly (10) for a power device (12), comprising: a housing (14) configured to be held in a hand of a user; one or more user interface elements (26) including at least one illuminable icon (28, 30, 32, 34) configured to be visible on an outer surface (24) of the housing (14); a primary printed circuit board (36) arranged within the housing (14); a secondary printed circuit board (38) arranged within the housing (14) and abutting an inner surface (40) of the housing (14), the secondary printed circuit board (38) being operatively coupled to the primary printed circuit board (36) via a connector(42); one or more secondary light sources (44) mounted on the secondary printed circuit board (38); one or more secondary light pipes (46) configured to convey light from the one or more secondary light sources (44) on the secondary printed circuit board (38) to the at least one illuminable icon (28, 30, 32, 34) and to provide uniform illumination of the at least one illuminable icon (28, 30, 32, 34).

2. The assembly of claim 1, wherein the one or more user interface elements (26) include a force gauge sensor (48) positioned juxtaposed the at least one illuminable icon.

3. The assembly of claim 1, further comprising one or more primary light sources (50) mounted on the primary printed circuit board (36).

4. The assembly of claim 3, further comprising a light baffle (82) coupled to the one or more primary light sources (50) on the primary printed circuit board (36) and configured to illuminate the at least one illuminable icon via an unobstructed light path, and together with the secondary light sources (44) provides uniform illumination of icons displayed on the outer surface of the housing.

5. The assembly of claim 4, wherein the light baffle (82) includes an optical grade translucent portion (92).

6. The assembly of claim 3, further comprising one or more primary light pipes (52) coupled to the one or more primary light sources (50) to illuminate the at least one icon and wherein the one or more primary light pipes (52) are arranged to avoid any obstruction of the light path.

7. The assembly of claim 1, wherein the one or more secondary light pipes (46) include a connecting member (76) to direct light to the at least one illuminable icon and prevent light from bleeding into an adjacent light pipe.

8. The assembly of claim 7, wherein the connecting member (76) includes a serrated surface (64, 66) to redirect light to the at least one illuminable icon.

9. The assembly of claim 7, wherein the connecting member (76) includes a chamfered portion (78).

10. The assembly of claim 1, further comprising one or more light shielding members (94) configured to prevent light emitted by the one or more secondary light sources from illuminating an icon that was not intended to be illuminated.

11. A method for uniform illumination of an icon on a housing (14) of a power device (12), the method comprising: providing a primary printed circuit board (36) within the housing (14); providing a secondary printed circuit board (38) within the housing (14) abutting an inner surface (40) of the housing (14); operatively coupling the secondary printed circuit board (38) to the primary printed circuit board (36) via a connector (42); mounting one or more secondary light sources (44) on the secondary printed circuit board

(38); coupling one or more secondary light pipes (46) to the one or more secondary light sources (44) to illuminate the icon such that the one or more secondary light sources (44) provide uniform illumination of the icons on the housing (14).

12. The method of claim 11, further comprising: providing one or more primary light sources (50) on the primary printed circuit board with one or more light baffles (82) to illuminate the icon.

13. The method of claim 12, further comprising: providing one or more primary light pipes (52) to the one or more primary light sources (50); and arranging the one or more primary light pipes (52) to illuminate the icon.

14. The method of claim 11, wherein the one or more secondary light pipes (46) include a serrated frame member (76) and one or more serrated light pipes (56, 58) to direct light to the illuminable icon and prevent light from bleeding into an adjacent light pipe.

15. The method of claim 11, further comprising: providing one or more light shielding members (94) configured to prevent light emitted by the one or more secondary light sources (44) from illuminating an icon that was not intended to be illuminated.

15