WO2015015292A1

WO2015015292A1 - Illuminated keypad assembly

Info

Publication number: WO2015015292A1
Application number: PCT/IB2014/001471
Authority: WO
Inventors: Louis BEAUMIER; Martial Bilodeau; Bertrand Mallette; Pierre Gaudet; Guillaume Robitalle BEAUMIER
Original assignee: Kongsberg Inc.
Priority date: 2013-08-02
Filing date: 2014-08-05
Publication date: 2015-02-05
Also published as: WO2015015292A8

Abstract

An illuminatable keypad assembly comprises a top member having at least one depressible touch section, a bottom member, and an intermediate member sandwiched between the top and bottom members. The intermediate member has a cavity extending from a second side towards a first side of the intermediate member to define a light guide aligned with the depressible touch section for guiding light toward the depressible touch section. The assembly further comprises a conductive element coupled to the top member and aligned with the depressible touch section, a capacitive sensor coupled to the bottom member for detecting a chance in capacitance when the depressible touch section is moved toward a depressed position, and a primary light source coupled to the bottom member and aligned with the light guide for emitting light through the light guide toward the depressible touch section for illuminating the depressible touch section.

Description

ILLUMINATED KEYPAD ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all the benefits of U.S. Provisional Patent Application Serial No. 61/861,819 filed on August 2, 2013, the contents of which are expressly incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

[0002] The present disclosure relates generally to keypads and, more particularly, to an illuminated keypad assembly.

BACKGROUND

[0003] Many electronic devices include a user interface device for allowing user interaction and user input. One user interface device is a button or a key. Conventional buttons include mechanical components to actuate a switch to indicate a button press or button activation. Mechanical buttons also provide a tactile feedback to the user to indicate the button has been pressed. More recently, touch-sensor buttons are being used in some applications to replace mechanical buttons. One type of touch-sensor button operates by way of capacitance sensing, utilizing capacitance sensor elements. The capacitance detected by a capacitance sensor changes as a function of the proximity of a conductive object on the sensor element. The conductive object can be, for example, a stylus or a user's finger. In a touch-sensor button, a change in capacitance detected by each sensor due to the proximity of a conductive object can be measured by a variety of methods. Regardless of the method, usually an electrical signal representative of the capacitance detected by each capacitance sensor is processed by a processing device, which in turn produces electrical or optical signals representative of the button or sensor activation of the touch-sensor button.

[0004] Accordingly, it is desirable to provide an assembly for a keypad having capacitance touch sensor activation that is illuminated. Thus, there is a need in the art to provide an assembly that meets at least one of these desires.

SUMMARY

[0005] An illuminated keypad assembly comprises a top member having an outer and inner surface and at least one depressible touch section movable between a rest position and a depressed position. The assembly further comprises a conductive element coupled to the top member and aligned with the depressible touch section. The assembly further comprises an intermediate member coupled to the top member and having opposed first and second sides with the first side adjacent the inner surface of the top member. The intermediate member has a cavity extending from the second side towards the first side to define a light guide aligned with the depressible touch section for guiding light toward the depressible touch section. The assembly further comprises a bottom member spaced from the top member adjacent the intermediate member such that the intermediate member is sandwiched between the top member and the bottom member. The assembly further comprises a capacitive sensor coupled to the bottom member and at least partially aligned with the depressible touch section for detecting a change in capacitance when the depressible touch section is moved toward the depressed position. The assembly further comprises a primary light source coupled to the bottom member and aligned with the light guide for emitting light through the light guide toward the depressible touch section for illuminating the depressible touch section. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description, when considered in connection with the accompanying drawings. It is to be appreciated that the figures are merely illustrative and are not necessarily drawn to scale.

[0007] Figure 1 is a perspective view of a portion of an interior of a vehicle including an example of an illuminated keypad assembly.

[0008] Figure 2 is a fragmented, semi-schematic, perspective view of an illuminated keypad assembly according to an embodiment of the present disclosure.

[0009] Figure 3 is a fragmented, sectional view of a top member of the illuminated keypad assembly with a depressible touch section shown in a rest position.

[0010] Figure 4 is a fragmented, sectional view of the top member of the illuminated keypad assembly with a depressible touch section shown in a fully depressed position.

[001 1] Figure 5 is a fragmented, enlarged, semi-schematic, sectional view of the illuminated keypad assembly of Figure 2 without a back cover member.

[0012] Figure 6 is a fragmented, exploded side view of the illuminated keypad assembly of Figure 5.

[0013] Figure 7 is a fragmented, plan view of the top member of the illuminated keypad assembly of Figure 5.

[0014] Figure 8 is a fragmented, plan view of an intermediate member of the illuminated keypad assembly of Figure 5. [0015] Figure 9 is a fragmented, plan view of a bottom member of the illuminated keypad assembly of Figure 5.

[0016] Figure 10 is semi-schematic, exploded side view of another embodiment of the illuminated keypad assembly.

[0017] Figure 1 1 is a semi-schematic, side sectional view of yet another embodiment of the illuminated keypad assembly.

[0018] Figure 12 is an enlarged, end sectional view of the illuminated keypad assembly of Figure 1 1 .

DETAILED DESCRIPTION

[0019] Referring now to the figures, wherein like numerals indicate corresponding parts throughout the several views, various embodiments of an illuminated keypad assembly 10, 1 10, 210 are shown throughout the figures and are described in detail below. The illuminated keypad assembly 10, 1 10, 210 may be a user interface for an electronic device. As shown in Figure 1, for example, the illuminated keypad assembly 10, 1 10, 210 may be used within an interior of a vehicle, such as an automobile. The illuminated keypad assembly 10, 1 10, 210 may also be used as a keyboard for a personal computer, as a keypad for a control panel of an airplane, etc. The illuminated keypad assembly 10, 110, 210 is generally designed to illuminate when a depressible touch section 20, 120, 220 (such as a burton or key) is depressed. In an example, the depressible touch section 20, 120, 220 may be illuminated utilizing a primary light source 34, 134, 234 (such as a light emitting diode (LED), which is schematically depicted in the figures) when the depressible touch section 20, 120, 220 is depressed. In another example, the illuminated keypad assembly 10, 1 10, 210 may also be illuminated with a backlight when the depressible touch section 20, 120, 220 is depressed. The keypad assembly 10, 1 10, 210 may also be an easily packaged capacitive touch keypad having a dual backlight function. Further, the keypad assembly 10, 1 10, 210 of the present disclosure provides tactile feedback to the user.

[0020] An embodiment of the illuminated keypad assembly 10 is described below with reference to Figures 2 through 9. As shown, the illuminated keypad assembly 10 includes a top member 12, an intermediate member 14, and a bottom member 16. The intermediate member 14 is coupled to the top member 12. The bottom member 16 is spaced from the top member 12 such that the intermediate member 14 is sandwiched between the top member 12 and the bottom member 14. The illuminated keypad assembly 10 may include a back cover member 18 to cover one side of the bottom member 16. The top member 12, intermediate member 14, bottom member 16, and cover member 18 is described in further detail below.

[0021] The top member 12 is a top layer of the illuminated keypad assembly 10 and acts as a visual interface for a user. The top member 12 may be a one-piece or multiple-piece membrane. The top member 12 is generally planar and has an outer surface 13 and an inner surface 15. In an example, and as shown, the top member 12 further has a rectangular shape. It is to be appreciated, however, that the top member 12 may have any suitable shape. Additionally, the top member 12 is flexible compared to the intermediate member 14, and may be made of, formed from, or comprise a polymeric or plastic material. Examples of suitable materials for the top member 12 are polycarbonates (such as LEXAN^® available from Saudi Basic Industries Corp., Sabic Innovative Plastics division, Pittsfield, MA), polyesters, and polyester blends. The top member 12 may also be partially or fully transparent. Said differently, the top member 12 may partially or fully transmit light.

[0022] The top member 12 further has at least one depressible touch section 20. As shown, the top member 12 has a plurality of depressible touch sections 20, where each depressible touch section 20 is spaced from an adjacent depressible touch section 20. The depressible touch sections 20 are generally arcuate in cross-sectional shape. As shown, the depressible touch sections 20 are square-shaped with rounded corners. The depressible touch sections 20 may otherwise be any desirable shape, such as circular, triangular, rectangular, etc. The depressible touch sections 20 are also concave relative to the inner surface 15 of the top member 12 when the depressible touch sections 20 are in a rest position. An example of the rest position (identified by the reference character R) is shown at least in Figure 3. For example, in the rest position R, the depressible touch section 20 protrudes outwardly toward the outer surface 13 of the top member 12. In the rest position R, the depressible touch section 20 resembles a dome.

[0023] Each depressible touch section 20 may be actuated by a user, such as by touching the depressible touch section 20 with the user's finger. When actuated, the depressible touch section 20 moves from the rest position R (as shown in Figure 3) to a fully depressed position D (an example of which is shown in Figure 4). It is to be appreciated that Figure 4 shows the depressible touch section 20 in a fully depressed position D. The shape of the depressible touch section 20 in the fully depressed position D is beneficial for illuminating the depressible touch section 20, as well as for improving the signal-to-noise ratio. It is also to be appreciated that the depressed position may also be any position of the depressible touch section 20 between the rest position R and the fully depressed position D.

[0024] The movement of the depressible touch section 20 between the rest position R and the depressed position D is due, at least in part, to the flexible nature of the top member 12 relative to the intermediate member 14. Further, the depressible touch section 20 provides physical feedback to the user when the user touches, presses, or actuates the depressible touch section 20. For example, when depressed, the depressible touch section 20 flexes toward the intermediate member 14 (such as toward the fully depressed position D) and flexes back toward the rest position R wiicii icicascu. i nc movement uaeis. luwai u me resi pusuiuii r . lypi auy piuviues tactile user feedback. In an example, the depressible touch section 20 may also be designed to provide a weak audible "click" feedback to the user when the depressible touch section 20 is released back to the rest position R.

[0025] In an example, and as shown, the keypad assembly 10 further has a conductive element 22 coupled to the top member 12. By the presence of the conductive element 22, the top member 12 is considered to be an at least partially conductive member. The conductive element 22 may be coupled to the outer surface 13 and/or the inner surface 15 of the top member 12. Additionally, the conductive element 22 may be a single conductive layer that extends across the entire outer 13 and/or inner 15 surfaces. Alternatively, the keypad assembly 10 may include a plurality of conductive elements 22, with each conductive element 22 being aligned with a respective one of the depressible touch sections 20. As shown, the conductive element 22 is coupled to the inner surface 15 of the top member 12 (again, which is adjacent to the intermediate member 14) and is aligned with the depressible touch section 20.

[0026] In an example, the conductive element 22 is a conductive layer of paint or ink. The conductive element 22 may be formed by painting the portion of the inner surface 15 which is aligned with the depressible touch section 20 with a conductive paint or ink. The conductive element 22 may or may not be connected to a ground (not shown). [0027] Activation of the depressible touch section 20 is accomplished by displacing, moving, or depressing the depressible touch section 20. Typically, the depressible touch section 20 may be activated by the user's touch, such as with his/her .-w.^ W l U ^ ^ΐ^* - rt ' _^l . . - J _A«_{-n n^} : 1 _n + may also or otherwise be activated using any non-conductive object, such as a glove (which may be worn by the person when activating the depressible touch section 20), a pencil, and/or the like. Accordingly, the keypad assembly 10 is designed to give the user some freedom to activate the depressible touch section 20 using more than just the user's bare finger.

[0028] In an example, the top member 12 comprises indicia 24 such as icons or user interface information. As shown in Figure 7, the indicia 24 may be formed by making larger areas of the top member 12 fully opaque, such as by spraying or painting (such as by silk screen painting) an ink on the outer surface 13 of the top member 12. In one example, the indicia 24 are formed on one or more of the depressible touch sections 20. In this example, the indicia 24 illuminates when a light (from a primary light source 34) is directed toward the depressible touch section(s) 20.

[0029] The intermediate member 14 is a middle layer of the illuminated keypad assembly 10, and acts as a support structure to support or maintain the top member 12 in position. As previously mentioned, the intermediate member 14 is coupled to the top member 12. In an example, the intermediate member 14 is directly coupled to the top member 12. Further, the intermediate member 14 is planar, and has opposed first 17 and second 19 sides with the first side 17 adjacent to the inner surface 15 of the top member 12. Further, the intermediate member 14 has a rectangular shape. It is to be appreciated, however, that the intermediate member 14 may have any suitable shape. In an example, the intermediate member 14 has substantially the same shape as the top member 12.

[0030] The intermediate member 14 further has a cavity 28 (such as an air gap) diffuser 29 which is aligned with the depressible touch section 20 for guiding light toward the depressible touch section 20. As shown, the light guide 29 is located directly below the depressible touch section 20. It is to be appreciated that where the keypad assembly 10 has a plurality of depressible touch sections 20, there is a light guide 29 aligned with each of the depressible touch sections 20.

[0031] The cavity 28 is generally defined by inner 3 1 and outer 33 walls extending from the second side 19 of the intermediate member 14 to the first side 17 of the intermediate member 14. The outer wall 33 is spaced a distance x from the inner wall 3 1 , and the distance x defines a thickness T of the cavity 28. Additionally, the cavity 28 has first 35 and second 37 ends and a height H defined between the first 35 and second 37 ends. As shown, the cavity 28 is closed at the first end 35 so that the cavity 28 is closed to the first side 17 of the intermediate member 14. In this instance, the cavity 28 extends toward the first side 17; however, the cavity 28 does not extend entirely through the intermediate member 14 and is not open to the first end 35. As also shown, the cavity 28 is open at the second end 37 so that the cavity 28 is open to the second side 19 of the intermediate member 14. It is to be appreciated that the cavity 28 may alternatively be designed so that the cavity 28 extends entirely through the intermediate member 14. In this instance, the cavity 28 would be open to both the first 35 and second 37 ends and in turn, would also be open to the first 17 and second 19 sides of the intermediate member 14. It is also to be appreciated that the cavity 28 may be alternatively designed so that the cavity 28 is closed at the second end 37 and extends toward the first end 35. In this instance, the cavity 28 would be open at the first end 35 and closed at the second end 37 and in turn, would be open to the first side 17 and closed to the second side 19 of the intermediate member 14,

[0032] In an example, and as shown, the inner 31 and outer 32 walls defining the cavity 28 are annular with the inner wall 31 having an inner diameter d| and the outer wall 32 having an outer diameter do- The outer diameter do is larger than the inner diameter di. In an example, the inner diameter d[ is consistent about a periphery 39 of the inner wall 31 and the outer diameter do is substantially consistent about a periphery 41 of the outer wall 33 along the height H of the cavity 28. To this end, the thickness T of the cavity 28 is also substantially consistent along the height H of the cavity 28. Additionally, each of the inner 31 and outer 33 walls is substantially straight along the height H of the cavity 28. The term substantially straight describes the contour of the inner 31 and outer 33 walls as having no or very little blemishes (such as ridges, pits, bumps, cracks, and/or the like), curves, angles, texturing, etc. Additionally, the inner 3 1 and outer 33 walls are substantially perpendicular to the second side 19 of the intermediate member 14. The term substantially perpendicular describes the orientation of the inner 3 1 and outer 33 walls relative to the second side 19 of the intermediate member 14, where each of the walls 31, 33 is close to or exactly 90° offset from the second side 19 of the intermediate member 14. With the inner 31 and outer 33 walls defining the cavity 28 being substantially perpendicular to the second side 19 of the intermediate member 14, the cavity 28 appears rectangular in cross-section and cylindrical or dough-nut shaped in plan view. In an example, the cavity 28 may have the shape of a prism. [0033] The depressible touch section 20 has a maximum width W. As shown, the maximum width W of the depressible touch section 20 is larger than the outer diameter d₀ (i.e., the diameter of the outer wall 33 of the cavity 28).

[0034] In an example, each of the inner 31 and outer 33 walls defining the cavity 28 has a polished surface. The polished surface, in addition to the features of the cavity 28 described above, facilitates transmission of light through the light guide 29 by total internal reflection of light. The operation of the light guide 29 with respect to the transmission of light toward the depressible touch section 20 is described in further detail below.

[0035] It is to be appreciated that the light guide 29 constitutes part of the intermediate member 14. The part of the intermediate member 14 is a portion of the intermediate member 14 that the cavity 28 surrounds. Additionally, the light guide 29 extends as high as the height H of the cavity 28. Said differently, the height of the light guide 29 and the height H of the cavity 28 are substantially the same.

[0036] Additionally, the portions of the intermediate member 14 that are not part of the light guides 29 include those portions of the intermediate member 14 to the right and left of each of the cavities 28, as well as those portions of the intermediate member 14 that extend above the light guides 29. As will be described further below, light which is emitted from the secondary light source(s) 36 illuminates all of the portions of the intermediate member 14 that are not part of the light guides 29. This, light, which is a backlight, illuminates the portions of the intermediate member to the right and left of each of the cavities 28, as well as the portions of the intermediate member 14 that extend above the light guides 29.

[0037] The intermediate member 14 is made of, formed from, or comprises a non- conductive material that is capable of transmitting, guiding, and/or diffusing light. In one example, the intermediate member 14 is made of, formed from, or comprises acrylic and/or polycarbonate. Further, the intermediate member 14 is formed as a single piece. The intermediate member 14 acts as a light diffuser, provides a strong support for the top member 12, and allows the ton member ! 2 to be separate from the bottom member 16. Accordingly, the intermediate member 14 may be referred to as a support member. Additionally, the intermediate member 14 serves to seal the bottom member 16 and the cover member 18 in a watertight manner, but is not necessarily waterproof.

[0038] The bottom member 16 is the bottom layer of the illuminated keypad assembly 10, and acts to integrate all of the electronic components of the assembly 10. For instance, the bottom member 16 includes electrical lead(s) and all of the electronics to control and drive capacitive sensor(s) 32, light sources (such as primary light source(s) 34 and secondary light source(s) 36), and all other electrical components to link with an outside interface.

[0039] The bottom member 16 may be referred to as a substrate. In one example, the bottom member 16 is a printed circuit board (PCB). As shown, the bottom member 16 is planar. Further, the bottom member 16 has a rectangular shape. It is to be appreciated, however, that the bottom member 16 may have any suitable shape. In an example, the bottom member 16 has substantially the same shape as the top member 12 and/or the intermediate member 14.

[0040] In an example, the bottom member 16 has at least one aperture or cut-out region 30. Typically, the aperture 30 is round, circular, or cylindrical in shape; however, the aperture 30 may have any suitable shape. As shown, the aperture 30 is aligned with the depressible touch section 20 of the top member 12. [0041 ] The illuminated keypad assembly 10 further comprises a capacitive sensor 32 coupled to the bottom member 16 and at least partially aligned with the depressible touch section 20. In an example, the keypad assembly 10 comprises a plurality of capacitive sensors 32 arranged around or in the periphery of the aperture 30. The capacitive sensors 32 detect or sense a change in capacitance when the depressible touch section 20 is moved toward the depressed position D. The value of the capacitance is a change in function of the distance between the depressible touch section 20 and the capacitive sensor 32. The capacitance detected by the capacitive sensor 32 changes as a function of the proximity of the conductive element 22 on the depressible touch section 20 relative to the capacitive sensor 32. A processing device (not shown) detects the activation of the depressible touch section 20 by a capacitive variation of the capacitive sensor 32 when the depressible touch section 20 is depressed. The operation of a change in capacitance of the capacitive sensor 32 is generally known.

[0042] The illuminated keypad assembly 10 further comprises at least one primary light source 34. Typically, the illuminated keypad assembly 10 has a plurality of light guides 29, and further has a primary light source 34 aligned with each of the light guides 29. The primary light source 34 is coupled to the bottom member 16. In an example, the primary light source 34 is a LED and is at least partially disposed within the aperture 30 of the bottom member 16. If not entirely within the aperture 30, the primary light source 34 may be partially underneath or behind the bottom member 16 and partially within the aperture 30. By being at least partially disposed within the aperture 30, the primary light source 30 can emit light directly toward the light guide 29. Said differently, the primary light source 34 may emit light directed substantially perpendicular to a horizontal plane PB of the bottom member 16. While the primary light source 34 may be coupled to the bottom member 16 but not within the aperture 30, it may be difficult to prevent the light from scattering and in turn, it may be difficult to channel most if not all of the light emitted from the primary light source 34 toward the light guide 29.

[0043] As previously mentioned, light emitted from the primary light source 34 is transmitted through the light guide 29 by total internal reflection. Total internal reflection is the total reflection of a light ray off of a boundary, such as the inner wall 31 of the cavity 28. An example of light rays reflecting off the inner wall 3 1 is shown in Figure 5, where the light rays are represented as arrows. Internal reflection typically occurs when light emitted from the primary light source 34 travels through a medium having a higher refractive index (such as the light guide 29) to a medium having a lower refractive index (such as the cavity 28). The light ray is bent away from the normal (of the wall 31) so an exit angle of the light ray is greater than an incident angle. Total internal reflection occurs when the incident angle is greater than a critical angle.

[0044] Further, internal specular reflection occurs when the light is traveling through the light guide 29. For instance, internal specular reflection occurs within the light guide 29 at the light guide-to-cavity interface (i.e., the inner wall 31). In an example, light rays internal to the light guide 29 that are incident to the light guide-to- cavity interface are totally internally reflected when the angle of incidence is 42° or greater.

[0045] It is to be appreciated that some light rays may not be internally reflected off the inner wall 31, and may pass into the cavity 28. The cavity 28, however, prevents the light rays from travelling further into the remaining portion of the intermediate member 14. In this instance, the light ray may be reflected off the outer wall 33 of the cavity 28 and back toward the light guide 29. Accordingly, light emitted from the primary light source 34 is transmitted through the light guide 29, and is not transmitted through or into any part of the remaining portion of the intermediate layer 14 to any significant degree. Said differently, the specularly reflected light transmitted through the light guided 29 is reflected without any significant loss of light.

[0046] The illuminated keypad assembly 10 further comprises a secondary, light source 36 (which is schematically depicted in the figures) spaced from the primary light source 34 and adjacent the intermediate member 14 for emitting a backlight to illuminate the intermediate member 14. In an example, the secondary light source(s) 36 is/are arranged on the top of the bottom member 16, such as between the bottom member 16 and the intermediate member 14. In an example, the secondary light source 36 is supported by the intermediate member 14. For instance, and as shown in Figures 5 and 6, the intermediate member 14 has a recess 25 for receiving and supporting each secondary light source 36. In another example, the secondary light source 36 is embedded in the intermediate member 14. The light of the secondary light sources 36 is directed substantially parallel to the horizontal plane Pi of the intermediate member 14 to illuminate the backlight portion 27 of the intermediate member 14. In an example, the secondary light sources 36 are LED's.

[0047] The light sources 34 and 36 may be of the same color or may be of different colors. Further, the light from the primary light sources 34 may act as status or "Tell-Tale" lighting, where there is a change in color when the associated function is activated. The light of the secondary light sources 36 acts as a backlight.

[0048] The cover member 18 is an outer member to cover the side of the bottom member 16 opposite the intermediate member 14. The cover member 18 may be planar and rectangular in shape, but may have any suitable shape. The cover member 18 may include an integrated connector 38 for attachment to an outside interface or source of power (not shown). The cover member 18 may have a cavity 40 to receive and support the top member 12, intermediate member 14, and bottom member 16 therein. In one embodiment, the intermediate member 14 may form a top cover and the bottom member 16 may form a bottom cover in which the covers are attached together by a suitable mechanism such as an adhesive, fastener, or clip. The cover member 18 is made of a suitable rigid material such as plastic.

[0049] In operation, power from a source (not shown) is supplied to bottom member 16 via the connector 38. The secondary light source 36 provide a common backlight for a first keypad area 42 (i.e., the backlight which illuminates the intermediate member 14 and is visible through the top member 12 in the first keypad area 42) and indicia 24. Each keypad area 42 has its own primary light to display if the key is activated or not. The primary light source 34 is dedicated to light the indicia 24 when the key is activated and consequently overwrites the backlight because light density of the primary light source 34 is greater than the secondary light source 36. The cavity 28 forms the light guide 29 in the intermediate member 14 and surrounds the primary light source 34 on side of the bottom member 16. The light from the primary light source 34 is transmitted through the light guide 29 of the intermediate member 14 by total internal reflection due to the cavity 28. For example, when the angle of refraction is 90°, the incident light ray is refracted along the boundary (i.e., the inner wall 31, and perhaps the outer wall 33 if light passes through the inner wall 31) of the cavity 28 according to SnelPs law. Internal specular reflection occurs within the light guide 29 at the guide surface-to-air (i.e., cavity) boundary to transmit light through the light guide 29. Light rays internal to the light guide 29 that are incident to the guide surface-to-air boundary are totally internally reflected when the angle of incidence is approximately 42° or greater for an acrylic material. It should be appreciated that specular reflected light rays are reflected without loss. It should also be appreciated that the cavity 28 prevents the light from the primary light source 34 from interfering with the diffused light or backlight from the secondary light source 36.

[0050] Referring to Figure 10, another embodiment of the illuminated keypad assembly 1 10 is shown and described below. In this embodiment, the illuminated keypad assembly 1 10 is similar to the illuminated keypad assembly 10 described above in connection with Figures 2-9 except that intermediate member 1 14 and the cover member are desgined so that the intermediate member 1 14 and the cover member 1 18 may be attached to one another.

[0051 ] As shown, the illuminated keypad assembly 1 10 includes a top member 1 12, an intermediate member 1 14, and a bottom member 1 16. The intermediate member 1 14 is coupled to the top member 1 12. The bottom member 1 16 is spaced from the top member 1 12 such that the intermediate member 14 is sandwiched between the top member 1 12 and the bottom member 1 14. The illuminated keypad assembly 1 10 may include a back cover member 1 18 to cover one side of the bottom member 1 16. The top member 1 12, intermediate member 1 14, bottom member 1 16, and cover member 1 18 is described in further detail below.

[0052] The top member 1 12 is a top layer of the illuminated keypad assembly 1 10 and acts as a visual interface for a user. The top member 1 12 may be a one-piece or multiple-piece membrane. The top member 1 12 is generally planar and has an outer surface 1 13 and an inner surface 1 15. In an example, and as shown, the top member 1 12 further has a rectangular shape. It is to be appreciated, however, that the top member 1 12 may have any suitable shape. Additionally, the top member 1 12 is flexible compared to the intermediate member 1 14, and may be made of, formed from, or comprise a polymeric or plastic material, examples of which are described

may also be partially or fully transparent. Said differently, the top member 1 12 may partially or fully transmit light.

[0053] The top member 1 12 further has at least one depressible touch section 120. As shown, the top member 1 12 has a plurality of depressible touch sections 120, where each depressible touch section 120 is spaced from an adjacent depressible touch section 120. The depressible touch sections 120 are generally arcuate in cross- sectional shape. As shown, the depressible touch sections 120 are square-shaped with rounded corners. The depressible touch sections 120 may otherwise be any desirable shape, such as circular, triangular, rectangular, etc. The depressible touch sections 120 are also concave relative to the inner surface 1 15 of the top member 1 12 when the depressible touch sections 120 are in a rest position. For example, in the rest position, the depressible touch sections 120 protrude outwardly toward the outer surface 1 13 of the top member 1 12, and each resembles a dome. Each depressible touch section 120 may be actuated by a user, such as by touching the depressible touch section 120 with the user's finger. When actuated, the depressible touch section 120 moves from the rest position to a depressed position.

[0054] The movement of the depressible touch section 120 between the rest position and the depressed position is due, at least in part, to the flexible nature of the top member 1 12 relative to the intermediate member 1 14. Further, the depressible touch sections 120 provide physical feedback to the user when the user touches, presses, or actuates the depressible touch sections 20. For example, when depressed, the depressible touch section 120 flexes toward the intermediate member 1 14 and flexes back toward the rest position when released. The movement back toward the rest position typically provides tactile user feedback. In an example, the depressible touch section 120 may also be designed to provide a weak audible "click" feedback to the user when the depressible touch section 120 is released back to the rest position.

[0055] The keypad assembly 110 further has a conductive element 122 coupled to the top member 1 12. By the presence of the conductive element 122, the top member 1 12 is considered to be an at least partially conductive member. The conductive element 122 may be coupled to the outer surface 1 13 and/or the inner surface 1 15 of the top member 1 12. Additionally, the conductive element 122 may be a single conductive layer that extends across the entire outer 1 13 and/or inner 1 15 surfaces. Alternatively, the keypad assembly 1 10 may include a plurality of conductive elements 122, with each conductive element 122 being aligned with a respective one of the depressible touch sections 120. As shown, the conductive element 122 is coupled to the inner surface 1 15 of the top member 1 12 (again, which is adjacent to the intermediate member 1 14) and is aligned with the depressible touch section 120.

[0056] In an example, the conductive element 122 is a conductive layer of paint or ink. The conductive element 122 may be formed by painting the portion of the inner surface 1 15 which is aligned with the depressible touch section 120 with a conductive paint or ink. The conductive element 122 may or may not be connected to a ground (not shown).

[0057] Activation of the depressible touch sections 120 is accomplished by displacing, moving, or depressing the depressible touch sections 120. Typically, the depressible touch section 120 may be activated by the user's touch, such as with his/her bare finger. With the presence of conductive ink, the depressible touch section 20 may also or otherwise be activated using any non-conductive object, such as a glove, a pencil, and/or the like. Accordingly, the keypad assembly 1 10 is designed to give the user some freedom to activate the depressible touch section 120 using more than just the user's bare finger.

[0058] In an example, the top member 1 12 comprises indicia (not shown) such as icons or user interface information. The indicia may be formed by making larger areas of the top member 1 12 fully opaque, such as by spraying or painting (such as by silk screen painting) an ink on the outer surface 1 13 of the top member 112. In one example, the indicia are formed on the depressible touch sections 120. In this example, the indicia illuminates when a light (from a primary light source 134) is directed toward the depressible touch sections 120.

[0059] The intermediate member 1 14 is a middle layer of the illuminated keypad assembly 1 10, and acts as a support structure to support or maintain the top member 1 12 in position. As previously mentioned, the intermediate member 1 14 is coupled to the top member 1 12. In an example, the intermediate member 1 14 is directly coupled to the top member 1 12. Further, the intermediate member 1 14 is planar, and has opposed first 1 17 and second 1 19 sides with the first side 1 17 adjacent to the inner surface 1 15 of the top member 1 12. Further, the intermediate member 1 14 has a rectangular shape. It is to be appreciated, however, that the intermediate member 1 14 may have any suitable shape. In an example, the intermediate member 14 has substantially the same shape as the top member 1 12.

[0060] The intermediate member 1 14 further has a cavity 128 (such as an air gap) extending from the second side 1 19 toward the first side 1 17 to define a light guide or diffuser 129 which is aligned with the depressible touch section 120 for guiding light toward the depressible touch section 120. As shown, the light guide 129 is located directly below the depressible touch section 120. It is to be appreciated that where the keypad assembly 110 has a plurality of depressible touch sections 120, there is a light guide 129 aligned with each of the depressible touch sections 120.

[006 i ] The cavity Ί 28 is generally defined by inner 131 and outer 133 wails extending from the second side 119 of the intermediate member 1 14 to the first side 1 17 of the intermediate member 1 14. The outer wall 133 is spaced a distance from the inner wall 131, and the distance defines a thickness of the cavity 128. Additionally, the cavity 128 has first 135 and second 137 ends and a height defined between the first 135 and second 137 ends. As shown, the cavity 128 is closed at the first end 135 so that the cavity 128 is closed to the first side 1 17 of the intermediate member 1 14. in this instance, the cavity 128 extends toward the first side 1 17; however, the cavity 128 does not extend entirely through the intermediate member 1 14 and is not open to the first end 135. As also shown, the cavity 128 is open at the second end 137 so that the cavity 128 is open to the second side 1 19 of the intermediate member 1 14. It is to be appreciated that the cavity 128 may alternatively be designed so that the cavity 128 extends entirely through the intermediate member 1 14. In this instance, the cavity 128 would be open to both the first 135 and second 137 ends and in turn, would also be open to the first 1 17 and second 1 19 sides of the intermediate member 1 14. It is also to be appreciated that the cavity 128 may be alternatively designed so that the cavity 128 is closed at the second end 137 and extends toward the first end 135. In this instance, the cavity 128 would be open at the first end 135 and closed at the second end 137 and in turn, would be open to the first side 1 17 and closed to the second side 1 19 of the intermediate member 1 14.

[0062] In an example, the inner 131 and outer 132 walls defining the cavity 128 are annular with the inner wall 131 having an inner diameter and the outer wall 132 having an outer diameter. The outer diameter is larger than the inner diameter. In an example, the inner diameter is consistent about a periphery of the inner wall 131 and the outer diameter is substantially consistent about a periphery of the outer wall 133 along the height H of the cavity 128. To this end, the thickness of the cavity 128 is also substantially consistent along the height of the cavity 128. Additionally, each of the inner 131 and outer 133 walls is substantially straight along the height of the cavity 128. Additionally, the inner 131 and outer 133 walls are substantially perpendicular to the second side 1 19 of the intermediate member 1 14. With the inner 131 and outer 133 walls defining the cavity 128 being substantially perpendicular to the second side 1 19 of the intermediate member 1 14, the cavity 128 appears rectangular in cross-section and cylindrical or dough-nut shaped in plan view. In an example, the cavity 28 may have the shape of a prism.

[0063] In an example, the depressible touch section 120 has a maximum width which is larger than the outer d iameter of the outer wall 133 of the cavity 128.

[0064] In an example, each of the inner 131 and outer 133 walls defining the cavity 128 has a polished surface. The polished surface, in addition to the features of the cavity 128 described above, facilitates transmission of light through the light guide 129 by total internal reflection of light. The operation of the light guide 129 with respect to the transmission of light toward the depressible touch section 120 is described in further detail below.

[0065] It is to be appreciated that the light guide 129 constitutes part of the intermediate member 1 14. The part of the intermediate member 1 14 is a portion of the intermediate member 1 14 that the cavity 128 surrounds. Additionally, the light guide 129 extends as high as the height of the cavity 128. Said differently, the height of the light guide 129 and the height of the cavity 128 are substantially the same. [0066] Additionally, the portions of the intermediate member 1 14 that are not part of the light guides 129 include those portions of the intermediate member 1 14 to the right and left of each of the cavities 128, as well as those portions of the intermediate member 1 14 that extend above the light guides 129. As will be described further below, light which is emitted from the secondary light source(s) 136 illuminates all of the portions of the intermediate member 114 that are not part of the light guides 129. This light, which is a backlight, illuminates the portions of the intermediate member to the right and left of each of the cavities 128, as well as the portions of the intermediate member 14 that extend above the light guides 129.

[0067] The intermediate member 1 14 is made of, formed from, or comprises a non-conductive material that is capable of transmitting, guiding, and/or diffusing light. In one example, the intermediate member 1 14 is made of, formed from, or comprises acrylic and/or polycarbonate. Further, the intermediate member 1 14 is formed as a single piece. The intermediate member 1 14 acts as a light diffuser, provides a strong support for the top member 1 12, and allows the top member 1 12 to be separate from the bottom member 1 16. Accordingly, the intermediate member 1 14 may be referred to as a support member. Additionally, the intermediate member 1 14 serves to seal the bottom member 116 and the cover member 1 18 in a watertight manner, but is not necessarily waterproof.

[0068] The bottom member 1 16 is the bottom layer of the illuminated keypad assembly 1 10, and acts to integrate all of the electronic components of the assembly 1 10. For instance, the bottom member 1 16 includes electrical lead(s) and all of the electronics to control and drive capacitive sensor(s) 132, light sources (such as primary light source(s) 134 and secondary light source(s) 136), and all other electrical components to link with an outside interface. [0069] The bottom member 1 16 may be referred to as a substrate. In one example, the bottom member 16 is a printed circuit board (PCB). As shown, the bottom member 1 16 is planar. Further, the bottom member 1 16 has a rectangular shape, it is to be appreciated, however, that the bottom member 1 16 may have any suitable shape. In an example, the bottom member 1 16 has substantially the same shape as the top member 1 12 and/or the intermediate member 1 14.

[0070] In an example, the bottom member 16 has at least one aperture or cut-out region 130. Typically, the aperture 130 is round, circular, or cylindrical in shape; however, the aperture 130 may have any suitable shape. As shown, the aperture 130 is aligned with the depressible touch section 120 of the top member 1 12.

[0071] The illuminated keypad assembly 1 10 further comprises a capacitive sensor 132 coupled to the bottom member 1 16 and at least partially aligned with the depressible touch section 120. In an example, the keypad assembly 1 10 comprises a plurality of capacitive sensors 132 arranged around or in the periphery of the aperture 130. The capacitive sensors 132 detect or sense a change in capacitance when the depressible touch section 120 is moved toward the depressed position. The value of the capacitance is a change in function of the distance between the depressible touch section 120 and the capacitive sensor 132. The capacitance detected by the capacitive sensor 132 changes as a function of the proximity of the conductive element 122 on the depressible touch section 120 relative to the capacitive sensor 132. A processing device (not shown) detects the activation of the depressible touch section 120 by a capacitive variation of the capacitive sensor 132 when the depressible touch section 120 is depressed. The operation of a change in capacitance of the capacitive sensor 132 is generally known. [0072] The illuminated keypad assembly 1 10 further comprises at least one primary light source 134. Typically, the illuminated keypad assembly 1 10 has a plurality of light guides 129, and further has a primary light source 134 aligned with each of the light guides 129, in an example, the primary light source 134 is a LED and is at least partially disposed within the aperture 130 of the bottom member 1 16. If not entirely within the aperture 130, the primary light source 134 may be partially underneath or behind the bottom member 1 16 and partially within the aperture 130. By being at least partially disposed within the aperture 130, the primary light source 130 can emit light directly toward the light guide 129. Said differently, the primary light source 134 may emit light directed substantially perpendicular to a horizontal plane P of the bottom member 1 16. While the primary light source 134 may be coupled to the bottom member 1 16 but not within the aperture 130, it may be difficult to prevent the light from scattering and in turn, it may be difficult to channel most if not all of the light emitted from the primary light source 134 toward the light guide 129.

[0073] As previously mentioned, light emitted from the primary light source 134 is transmitted through the light guide 129 by total internal reflection. Total internal reflection of the light transmitted through the light guide 129 is described in detail above.

[0074] The illuminated keypad assembly 1 10 further comprises a secondary light source 136 spaced from the primary light source 134 and adjacent the intermediate member 1 14 for emitting a backlight to illuminate the intermediate member 1 14. In an example, the secondary light source(s) 136 is/are arranged on the top of the bottom member 1 16, such as between the bottom member 16 and the intermediate member 1 14. In an example, the secondary light source 36 is supported by the intermediate member 1 14. For instance, and as shown, the intermediate member 1 14 has a recess 125 for receiving and supporting each secondary light source 136. The light of the secondary light source 136 is directed substantially parallel to the horizontal plane of the intermediate member 1 14 to illuminate the backlight portion 127 of the intermediate member 1 14. In an example, the secondary light sources 136 are LED's.

[0075] The light sources 134 and 136 may be of the same color or may be of different colors. Further, the light from the primary light sources 134 may act as status or "Tell-Tale" lighting, where there is a change in color when the associated function is activated. The light of the secondary light sources 136 acts as a backlight.

[0076] The cover member 1 8 is an outer member to cover the side of the bottom member 1 16 opposite the intermediate member 1 14. The cover member 1 18 may be generally planar and rectangular in shape, but may have any suitable shape. The cover member 1 18 may include an integrated connector 138 for attachment to an outside interface or source of power (not shown). In this embodiment, and as shown in Figure 10, the intermediate member 1 14 has a side wall 143 extending therefrom to form a top cover having a projection 142 near the lower inner edge thereof. The cover member 1 18 has a lock member 144 at the outer edge thereof with a recess 146 to receive the projection 142. In one embodiment, the projection 142 and recess 146 are generally V-shaped in cross-section, but may be any suitable shape. The cover member 1 18 and intermediate member 1 14 may be attached together by a suitable mechanism such as an adhesive, fastener, or clip from a back thereof. The cover member 1 18 is made of a suitable rigid material such as plastic.

[0077] It should be appreciated that the operation of the illuminated keypad assembly 1 10 is similar to the illuminated keypad assembly 10 described above. [0078] Another embodiment of the illuminated keypad assembly 210 is shown in Figures 1 1 and 12. In this embodiment, the illuminated keypad assembly 210 is similar to the keypad assembly 10 described above in connection with Figures 2-9, except that the cover member 218 is designed to lock with the bottom member 216 and further includes clip(s) 254 for attaching the keypad assembly 210 to another structure.

[0079] As shown, the illuminated keypad assembly 210 includes a top member 212, an intermediate member 214, and a bottom member 216. The intermediate member 214 is coupled to the top member 212. The bottom member 216 is spaced from the top member 212 such that the intermediate member 214 is sandwiched between the top member 212 and the bottom member 214. The illuminated keypad assembly 210 may include a back cover member 218 to cover one side of the bottom member 216. The top member 212, intermediate member 214, bottom member 216, and cover member 218 is described in further detail below.

[0080] The top member 212 is a top layer of the illuminated keypad assembly 210 and acts as a visual interface for a user. The top member 212 may be a one-piece or multiple-piece membrane. The top member 212 is generally planar and has an outer surface 213 and an inner surface 215. In an example, and as shown, the top member 212 further has a rectangular shape. It is to be appreciated, however, that the top member 212 may have any suitable shape. Additionally, the top member 212 is flexible compared to the intermediate member 214, and may be made of, formed from, or comprise a polymeric or plastic material, examples of which are described above with reference to the illuminated keypad assembly 10. The top member 212 may also be partially or fully transparent. Said differently, the top member 212 may partially or fully transmit light. [0081] The top member 212 further has at least one depressible touch section 220. As shown, the top member 212 has a plurality of depressible touch sections 220, where each depressible touch section 220 is spaced from an adjacent depressible touch section 220. The depressible touch sections 220 are generally arcuate in cross- sectional shape. As shown, the depressible touch sections 220 are square-shaped with rounded corners. The depressible touch sections 220 may otherwise be any desirable shape, such as circular, triangular, rectangular, etc. The depressible touch sections 220 are also concave relative to the inner surface 215 of the top member 212 when the depressible touch sections 220 are in a rest position. For example, in the rest position, the.depressible touch sections 220 protrude outwardly toward the outer surface 213 of the top member 212, and each resembles a dome. Each depressible touch section 220 may be actuated by a user, such as by touching the depressible touch section 220 with the user's finger. When actuated, the depressible touch section 220 moves from the rest position to a depressed position.

[0082] The movement of the depressible touch section 220 between the rest position and the depressed position is due, at least in part, to the flexible nature of the top member 212 relative to the intermediate member 214. Further, the depressible touch sections 220 provide physical feedback to the user when the user touches, presses, or actuates the depressible touch sections 220. For example, when depressed, the depressible touch section 220 flexes toward the intermediate member 14 and flexes back toward the rest position when released. The movement back toward the rest position typically provides tactile user feedback. In an example, the depressible touch section 220 may also be designed to provide a weak audible "click" feedback to the user when the depressible touch section 220 is released back to the rest position. [0083] The keypad assembly 210 further has a conductive element 222 coupled to the top member 212. By the presence of the conductive element 222, the top member 212 is considered to be an at least partially conductive member. The conductive element 222 may be coupled to the outer surface 213 and/or the inner surface 215 of the top member 212. Additionally, the conductive element 222 may be a single conductive layer that extends across the entire outer 213 and/or inner 21 surfaces. Alternatively, the keypad assembly 210 may include a plurality of conductive elements 222, with each conductive element 222 being aligned with a respective one of the depressible touch sections 220. As shown, the conductive element 222 is coupled to the inner surface 215 of the top member 212 (again, which is adjacent to the intermediate member 214) and is aligned with the depressible touch section 220.

[0084] In an example, the conductive element 222 is a conductive layer of paint or ink. The conductive element 222 may be formed by painting the portion of the inner surface 215 which is aligned with the depressible touch section 220 with a conductive paint or ink. The conductive element 222 may or may not be connected to a ground (not shown).

[0085] Activation of the depressible touch sections 220 is accomplished by displacing, moving, or depressing the depressible touch sections 220. Typically, the depressible touch section 220 may be activated by the user's touch, such as with his/her bare finger. With the presence of the conductive ink, the depressible touch section 220 may also or otherwise be activated using any non-conductive object, such as by a glove, a pencil, and/or the like. Accordingly, the keypad assembly 210 is designed to give the user some freedom to activate the depressible touch sections 220 using more than just the user's bare finger. [0086] In an example, the top member 212 comprises indicia (not shown) such as icons or user interface information. The indicia may be formed by making larger areas of the top member 212 fully opaque, such as by spraying or painting (such as by silk screen painting) an ink on the outer surface 1 1 3 of the top member 212. In one example, the indicia are formed on the depressible touch sections 220. In this example, the indicia illuminates when a light (from a primary light source 234) is directed toward the depressible touch sections 220.

[0087] The intermediate member 214 is a middle layer of the illuminated keypad assembly 210, and acts as a support structure to support or maintain the top member 212 in position. As previously mentioned, the intermediate member 214 is coupled to the top member 212. In an example, the intermediate member 214 is directly coupled to the top member 212. Further, the intermediate member 214 is planar, and has opposed first 217 and second 219 sides with the first side 217 adjacent to the inner surface 215 of the top member 212. Further, the intermediate member 214 has a rectangular shape. It is to be appreciated, however, that the intermediate member 214 may have any suitable shape. In an example, the intermediate member 14 has substantially the same shape as the top member 212.

[0088] The intermediate member 214 further has a cavity 228 (such as an air gap) extending from the second side 219 toward the first side 217 to define a light guide or diffuser 229 which is aligned with the depressible touch section 220 for guiding light toward the depressible touch section 220. As shown, the light guide 229 is located directly below the depressible touch section 220. It is to be appreciated that where the keypad assembly 210 has a plurality of depressible touch sections 220, there is a light guide 229 aligned with each of the depressible touch sections 220. [0089] The cavity 228 is generally defined by inner 231 and outer 233 walls extending from the second side 219 of the intermediate member 214 to the first side 217 of the intermediate member 214. The outer wall 233 is spaced a distance from the inner wall 231. and the distance defines a thickness of the cavity 228. Additionally, the cavity 228 has first 235 and second 237 ends and a height defined between the first 35 and second 37 ends. As shown, the cavity 228 is closed at the first end 235 so that the cavity 228 is closed to the first side 217 of the intermediate member 214. In this instance, the cavity 228 extends toward the first side 217; however, the cavity 228 does not extend entirely through the intermediate member 214 and is not open to the first end 235. As also shown, the cavity 228 is open at the second end 237 so that the cavity 228 is open to the second side 219 of the intermediate member 214. It is to be appreciated that the cavity 228 may alternatively be designed so that the cavity 228 extends entirely through the intermediate member 214. In this instance, the cavity 228 would be open to both the first 235 and second 237 ends and in turn, would also be open to the first 217 and second 219 sides of the intermediate member 214. It is also to be appreciated that the cavity 228 may be alternatively designed so that the cavity 228 is closed at the second end 237 and extends toward the first end 235. In this instance, the cavity 228 would be open at the first end 235 and closed at the second end 237 and in turn, would be open to the first side 2 17 and closed to the second side 219 of the intermediate member 214.

[0090] In an example, the inner 231 and outer 232 walls defining the cavity 228 are annular with the inner wall 231 having an inner diameter and the outer wall 232 having an outer diameter. The outer diameter is larger than the inner diameter. In an example, the inner diameter is consistent about a periphery 239 of the inner wall 231 and the outer diameter is substantially consistent about a periphery 241 of the outer wall 233 along the height of the cavity 228. To this end, the thickness of the cavity 228 is also substantially consistent along the height of the cavity 228. Additionally, each of the inner 231 and outer 233 walls is substantially straight along the height H of the cavity 228. Additionally, the inner 231 and outer 233 walls are substantially perpendicular to the second side 219 of the intermediate member 214. With the inner 23 1 and outer 233 walls defining the cavity 228 being substantially perpendicular to the second side 219 of the intermediate member 214, the cavity 228 appears rectangular in cross-section and cylindrical or dough-nut shaped in plan view. In an example, the cavity 218 may have the shape of a prism.

[0091 ] In an example, the depressible touch section 220 has a maximum width which is larger than the outer diameter of the outer wall 233 of the cavity 228.

[0092] In an example, each of the inner 231 and outer 233 walls defining the cavity 228 has a polished surface. The polished surface, in addition to the features of the cavity 228 described above, facilitates transmission of light through the light guide 229 by total internal reflection of light. The operation of the light guide 229 with respect to the transmission of light toward the depressible touch section 220 is described in further detail below.

[0093] It is to be appreciated that the light guide 229 constitutes part of the intermediate member 214. The part of the intermediate member 214 is a portion of the intermediate member 214 that the cavity 228 surrounds. Additionally, the light guide 229 extends as high as the height of the cavity 228. Said differently, the height of the light guide 229 and the height of the cavity 228 are substantially the same.

[0094] Additionally, the portions of the intermediate member 214 that are not part of the light guides 229 include those portions of the intermediate member 214 to the right and left of each of the cavities 228, as well as those portions of the intermediate member 214 that extend above the light guides 229. As will be described further below, light which is emitted from the secondary light source(s) 236 illuminates all of the portions of the intermediate member 214 that are not part of the light guides 229. una iigin, winuii 13 a

iiiuiiuiiaics me portions ui me uiieniieuiaie memuer to the right and left of each of the cavities 228, as well as the portions of the intermediate member 14 that extend above the light guides 229.

[0095] The intermediate member 214 is made of, formed from, or comprises a non-conductive material that is capable of transmitting, guiding, and/or diffusing light. In one example, the intermediate member 214 is made of, formed from, or comprises acrylic and/or polycarbonate. Further, the intermediate member 214 is formed as a single piece. The intermediate member 214 acts as a light diffuser and provides a strong support for the top member 212 and allows the top member 212 to be separate from the bottom member 216. Accordingly, the intermediate member 214 may be referred to as a support member. Additionally, the intermediate member 214 serves to seal the bottom member 216 and the cover member 218 in a watertight manner, but is not necessarily waterproof.

[0096] The bottom member 216 is the bottom layer of the illuminated keypad assembly 210, and acts to integrate all of the electronic components of the assembly 210. For instance, the bottom member 216 includes electrical lead(s) and all of the electronics to control and drive capacitive sensor(s) 232, light sources (such as primary light source(s) 234 and secondary light source(s) 236), and all other electrical components to link with an outside interface.

[0097] The bottom member 216 may be referred to as a substrate. In one example, the bottom member 216 is a printed circuit board (PCB). As shown, the bottom member 216 is planar. Further, the bottom member 216 has a rectangular shape. It is to be appreciated, however, that the bottom member 216 may have any suitable shape. In an example, the bottom member 216 has substantially the same shape as the top member 212 and/or the intermediate member 214.

rODORl in ¾n Viimnl c

region 130. Typically, the aperture 230 is round, circular, or cylindrical in shape; however, the aperture 230 may have any suitable shape. As shown, the aperture 230 is aligned with the depressible touch section 220 of the top member 212.

[0099] The illuminated keypad assembly 210 further comprises a capacitive sensor 232 coupled to the bottom member 216 and at least partially aligned with the depressible touch section 220. In an example, the keypad assembly 210 comprises a plurality of capacitive sensors 232 arranged around or in the periphery of the aperture 230. The capacitive sensors 232 detect or sense a change in capacitance when the depressible touch section 220 is moved toward the depressed position. The value of the capacitance is a change in function of the distance between the depressible touch section 220 and the capacitive sensor 232. The capacitance detected by the capacitive sensor 232 changes as a function of the proximity of the conductive element 222 on the depressible touch section 220 relative to the capacitive sensor 232. A processing device (not shown) detects the activation of the depressible touch section 220 by a capacitive variation of the capacitive sensor 232 when the depressible touch section 220 is depressed. The operation of a change in capacitance of the capacitive sensor 232 is generally known.

[00100] The illuminated keypad assembly 210 further comprises at least one primary light source 234. Typically, the illuminated keypad assembly 210 has a plurality of light guides 229, and further has a primary light source 234 aligned with each of the light guides 229. In an example, the primary light source 234 is a LED and is at least partially disposed within the aperture 230 of the bottom member 216. If not entirely within the aperture 230, the primary light source 234 may be partially underneath or behind the bottom member 216 and partially within the aperture 230. By being at ieast partially disposed within the aperture 230, t e primary light source 230 can emit light directly toward the light guide 229. Said differently, the primary light source 234 may emit light directed substantially perpendicular to a horizontal plane of the bottom member 216. While the primary light source 234 may be coupled to the bottom member 216 but not within the aperture 230, it may be difficult to prevent the light from scattering and in turn, it may be difficult to channel most if not all of the light emitted from the primary light source 234 toward the light guide 229.

[00101 ] As previously mentioned, light emitted from the primary light source 234 is transmitted through the light guide 229 by total internal reflection. Total internal reflection of the light transmitted through the light guide 229 is described in detail above.

[00102] The illuminated keypad assembly 210 further comprises a secondary light source 236 spaced from the primary light source 234 and adjacent the intermediate member 214 for emitting a backlight to illuminate the intermediate member 214. In an example, the secondary light source(s) 236 is/are arranged on the top of the bottom member 216, such as between the bottom member 216 and the intermediate member 214. In an example, the secondary light source 36 is supported by the intermediate member 214. For instance, and as shown, the intermediate member 214 has a recess 125 for receiving and supporting each secondary light source 236. The light of the secondary light source 236 is directed substantially parallel to the horizontal plane of the intermediate member 214 to illuminate the backlight portion 227 of the intermediate member 214. In an example, the secondary light sources 236 are LED's. [00103] The light sources 234 and 236 may be of the same color or may be of different colors. Further, the light from the primary light sources 234 may act as status or "Tell-Tale" lighting, where there is a change in color when the associated function is activated. The light of the secondary light sources 236 acts as a backlight.

[00104] The cover member 218 is an outer member to cover the side of the bottom member 216 opposite the intermediate member 214. The cover member 218 may be generally planar and rectangular in shape, but may have any suitable shape. The cover member 218 may include an integrated connector 238 for attachment to an outside interface or source of power (not shown). The cover member 218 may have a cavity 240 to receive and support the top member 212, intermediate member 214, and bottom member 216 therein. In this embodiment, and as shown in Figures 1 1 and 12, the bottom member 216 has one or more apertures 250 extending therethrough. The cover member 216 has one or more lock member 244 extending into the cavity 240 and through the aperture 250 in the bottom member 216. The lock member 244 has a projection 252 near the upper end thereof. In one embodiment, the projection 252 is generally triangular shaped in cross-section, but may be any suitable shape. In one embodiment, the top member 212, intermediate member 214 and the bottom member 216 may be attached together by a suitable mechanism such as an adhesive, fastener, or clip.

[00105] The cover member 218 may include one or more clips 254 for attaching the illuminated keypad assembly 210 to other structure. As illustrated in Figure 12, the clip 254 extends outwardly from and is cantilevered to the cover member 218. The clip 254 has a general "U" shape. The clip 254 may include a plurality of teeth 256 on an upper end thereof for gripping to the structure to which it is attached. The cover member 218 is made of a suitable rigid material such as plastic. The cover member 218 is integral, unitary, and one-piece. It should be appreciated that the operation of the illuminated keypad assembly 210 is similar to the illuminated keypad assembly 10. It should be appreciated that the clips 254 flex.

[00106] While the invention lias been described with reference to the examples above, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all examples falling within the scope of the appended claims.

Claims

CLAIMS What is claimed is:

1. An illuminatable keypad assembly comprising:

a top member having an outer and inner surface -uiu at least one depressiulc touch section movable between a rest position and a depressed position;

a conductive element coupled to said top member and aligned with said depressible touch section;

an intermediate member coupled to said top member and having opposed first and second sides with said first side adjacent said inner surface of said top member, and said intermediate member having a cavity extending from said second side towards said first side to define a light guide aligned with said depressible touch section for guiding light toward said depressible touch section;

a bottom member spaced from said top member adjacent said intermediate member such that said intermediate member is sandwiched between said top member and said bottom member;

a capacitive sensor coupled to said bottom member and at least partially aligned with said depressible touch section for detecting a change in capacitance when said depressible touch section is moved toward said depressed position; and

a primary light source coupled to said bottom member and aligned with said light guide for emitting light through said light guide toward said depressible touch section for illuminating said depressible touch section.

2. The assembly as set forth in claim 1 wherein said cavity is defined by outer and inner walls extending from said second side toward said first side of said intermediate member, with said outer wall being spaced a distance from said inner wall.

3. The assembly as set forth in claim 2 wherein said cavity has a height and said distance between said inner and outer walls defines a thickness of said cavity that is substantially consistent along said height of said cavity.

4= The assembly as set forth in claim 2 wherein said outer and inner walls are annular with said outer and inner walls having an outer and inner diameter, respectively, with said outer diameter being larger than said inner diameter and being consistent about a periphery of said outer wall, and said inner diameter being consistent about a periphery of said inner wall.

5. The assembly as set forth in claim 2 wherein said cavity has a height, and each of said outer and inner walls is substantially straight along said height of said cavity.

6. The assembly as set forth in claim 2 wherein each of said outer and inner walls is substantially perpendicular to said second side of said intermediate member.

7. The assembly as set forth in claim 2 wherein each of said inner and outer walls has a polished surface for facilitating transmission of light through said light guide by total internal reflection of light.

8. The assembly as set forth in claim 2 wherein said depressible touch section has a maximum width which is larger than said outer diameter.

9. The assembly as set forth in claim 2 wherein said cavity has first and second ends and a height defined between said first and second ends, with said cavity being closed at said first end so that said cavity is closed to said first side of said intermediate member.

10. The assembly as set forth in claim 9 wherein said cavity is open at said second end so that said cavity is open to said second side of said intermediate member.

1 i

;n claim 1 wherein said bottom member has ail aperture, and said primary light source is a light emitting diode (LED) that is at least partially disposed within said aperture.

12. The assembly as set forth in claim 1 further comprising a secondary light source spaced from said primary light source and adjacent said intermediate member for emitting a backlight to illuminate said intermediate member.

13. The assembly as set forth in claim 12 wherein said secondary light source is supported by said intermediate member.

14. The assembly as set forth in claim 13 wherein said intermediate member has a backlight portion which is adjacent said cavity and extends above said light guide so that backlight emitted from said secondary light source is transmitted through and across said intermediate member.

15. The assembly as set forth in claim 13 wherein said intermediate member further comprises a recess for receiving and supporting said secondary light source.

16. The assembly as set forth in claim 1 wherein said capacitive sensor is one of a plurality of capacitive sensors, with said plurality of capacitive sensors being arranged about a periphery of said aperture of said bottom member.

17. The assembly as set forth in claim 1 wherein said depressible touch section is concave relative to said bottom surface of said top member when said depressible touch section is in said rest position.

18. The assembly as set forth in claim 1 wherein said depressible touch section is one of a plurality of depressible touch sections and said conductive element is one of a plurality of conductive elements, with each of said conductive elements being coupled to said bottom surface of said top member and adjacent to a respective one of said depressible touch sections.