PATENT DOCUMENT

Publication Number: US-9997304-B2
Application Number: US-201615154723-A
Country: US
Kind Code: B2

Title: Uniform illumination of keys

Abstract:
Systems and methods for providing illumination to illuminable portions of keys associated with a keyboard are described. A key includes a light guide positioned below a keycap. The light guide includes one or more sidewalls that exhibit high internal reflection. In many examples, light guide sidewalls are formed with one or more prisms.

Claims:
What is claimed is: 
     
       1. A key for a keyboard comprising:
 a keycap disposed within an aperture defined by the keyboard; 
 a structural body positioned beneath the keycap and defining an opening, the structural body formed from an optically translucent material; 
 a compressible dome positioned below the keycap and at least partially within the opening of the structural body; 
 a key mechanism coupled to the keycap and pivotally engaged with a sidewall of the structural body; and 
 a light emitting element optically coupled to the structural body. 
 
     
     
       2. The key of  claim 1 , wherein the structural body has a prismatic sidewall within the opening. 
     
     
       3. The key of  claim 2 , wherein the structural body comprises an internally reflective surface. 
     
     
       4. The key of  claim 3 , wherein the internally reflective surface comprises a rectilinear through-hole. 
     
     
       5. The key of  claim 2 , wherein the structural body comprises a light guide. 
     
     
       6. A key comprising:
 a keycap defining an input surface of the key; 
 a compressible dome below the keycap; 
 a light emitting element; 
 a light guide optically coupled to the light emitting element and defining:
 an opening at least partially surrounding the compressible dome; and 
 an interlock feature positioned on a sidewall of the light guide; and 
 
 a key mechanism engaged with the interlock feature and with the keycap and configured to guide the keycap between a depressed position and an undepressed position. 
 
     
     
       7. The key of  claim 6 , wherein the keycap comprises an illuminable portion. 
     
     
       8. The key of  claim 7 , wherein the illuminable portion comprises a glyph formed from an optically translucent material. 
     
     
       9. The key of  claim 7 , wherein the key mechanism at least partially surrounds the light emitting element. 
     
     
       10. The key of  claim 9 , wherein the key mechanism comprises a butterfly mechanism. 
     
     
       11. The key of  claim 6 , wherein the light guide forms a ring. 
     
     
       12. The key of  claim 6 , wherein:
 the sidewall is an outer sidewall; and 
 the light guide comprises:
 a top endcap surface; 
 a bottom endcap surface; and 
 an inner sidewall extending from the top endcap surface to the bottom endcap surfaces and having a greater internal reflection than the top endcap surface. 
 
 
     
     
       13. The key of  claim 12 , wherein the outer sidewall has a greater internal reflection than the top endcap surface. 
     
     
       14. The key of  claim 12 , wherein each of the inner sidewall and the outer sidewall form one or more prisms. 
     
     
       15. An input structure for an electronic device, comprising:
 an input surface comprising an illuminable portion; 
 a collapsible dome positioned below the input surface; 
 a depressible mechanism positioned around the collapsible dome and coupled to the input surface, the depressible mechanism configured to move the input surface downward to collapse the collapsible dome in response to an external force on the input surface; 
 a body coupled to the depressible mechanism and the collapsible dome; 
 a light guide positioned around the collapsible dome and within the body, the light guide optically coupled to the illuminable portion; and 
 a light emitting element optically coupled to the light guide and configured to illuminate the illuminable portion through the light guide. 
 
     
     
       16. The input structure of  claim 15 , wherein the light guide defines an inner sidewall and an outer sidewall. 
     
     
       17. The input structure of  claim 16 , wherein the light guide is optically coupled to the light emitting element. 
     
     
       18. The input structure of  claim 16 , wherein the inner sidewall and the outer sidewall of the light guide each form a series of prisms. 
     
     
       19. The input structure of  claim 15 , wherein the light guide is insert-molded into the body. 
     
     
       20. The input structure of  claim 15 , wherein the body comprises a reflective surface that is oblique to the light emitting element. 
     
     
       21. The key of  claim 1 , wherein the key mechanism at least partially surrounds the structural body when the key is in a depressed configuration. 
     
     
       22. The key of  claim 6 , wherein the key mechanism at least partially surrounds the light guide when the key is in a depressed configuration.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 62/161,038, filed May 13, 2015 and titled “Uniform Illumination of Keys,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     Embodiments described herein are directed to input devices for computing systems and, more particularly, to systems and methods for facilitating substantially uniform illumination of select features of such input devices. 
     BACKGROUND 
     Electronic devices can receive user input from a keyboard, some keys of which may be illuminable and thus visible to a user in dimly-lit environments. A key can be illuminated in a number of ways. For example, a light-emitting diode (“LED”) can be disposed behind a keycap of an illuminable key to direct light toward and through a translucent portion of the keycap. In many cases, the location, orientation, and size of such an LED is limited by the structure of the key itself, which, in turn, affects the quality, uniformity, and quantity of light visible to a user. 
     SUMMARY 
     Embodiments described herein disclose a keyboard including a group of keys. At least one key of the group of keys includes a compressible dome, a light emitting element, and a light guide that is positioned at least partially around the compressible dome and optically coupled to the light emitting element. Some embodiments may include an illuminable keycap positioned over the compressible dome 
     In certain keys, the light guide includes a body that defines an inner sidewall, an outer sidewall, a top endcap surface, and a bottom endcap surface. The inner sidewall may exhibit greater internal reflection than the top endcap surface. The inner sidewall and the outer sidewall form one or more prisms. 
     Some embodiments take the form of a key for a keyboard, comprising: a keycap disposed within an aperture defined by the keyboard; a compressible dome positioned below the keycap; a key mechanism positioned around the compressible dome and coupled to the keycap; a structural body positioned beneath the key mechanism and formed from an optically translucent material, the structural body coupled to the key mechanism; and a light emitting element optically coupled to the structural body. 
     Other embodiments take the form of an input structure for an electronic device, comprising: an input surface comprising an illuminable portion; a collapsible dome positioned below the input surface; a depressible mechanism positioned around the collapsible dome and coupled to the input surface, the depressible mechanism configured to move the input surface downward to collapse the collapsible dome in response to an external force on the input surface; a body coupled to the depressible mechanism and the collapsible dome; a light guide positioned around the collapsible dome and within the body, the light guide optically coupled to the illuminable portion; and a light emitting element optically coupled to the light guide and configured to illuminate the illuminable portion through the light guide. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to representative embodiments illustrated in the accompanying figures. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments as defined by the appended claims. 
         FIG. 1A  depicts an electronic device incorporating a keyboard with illuminable keys. 
         FIG. 1B  depicts the enclosed circle A-A of  FIG. 1A . 
         FIG. 2A  depicts an example key mechanism that may be used with an illuminable key of the keyboard shown in  FIGS. 1A-1B . 
         FIG. 2B  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , particularly showing an example light guide. 
         FIG. 3  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , particularly showing another example light guide. 
         FIG. 4  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , particularly showing another example light guide. 
         FIG. 5  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , particularly showing another example light guide. 
         FIG. 6A  depicts an example light guide having a prismatic sidewall. 
         FIG. 6B  depicts another example light guide having a prismatic sidewall. 
         FIG. 6C  depicts still another example light guide having a prismatic sidewall. 
         FIG. 6D  depicts yet another example light guide having an internally scalloped sidewall. 
         FIG. 6E  depicts a further example light guide having an externally scalloped sidewall. 
         FIG. 6F  depicts an example ring-shaped light guide having an internally-scalloped sidewall. 
         FIG. 7A  depicts an example light guide defining a prismatic through-hole. 
         FIG. 7B  depicts another example light guide defining a prismatic through-hole. 
         FIG. 7C  depicts another example light guide defining a prismatic through-hole and three internal reflective surfaces. 
         FIG. 8  is a flow chart depicting operations of a method of manufacturing a light guide. 
         FIG. 9  is a flow chart depicting operations of a method of manufacturing a light guide based on a selected glyph. 
     
    
    
     The use of the same or similar reference numerals in different figures indicates similar, related, or identical items. 
     The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Embodiments described herein reference systems and methods that illuminate one or more keys of a keyboard. An illuminable key includes a light emitting element, such as a light-emitting diode, that is optically coupled to a light guide positioned beneath the key. The light guide conveys light from the light emitting element to an illuminable portion of the key. 
     As used herein, the phrase “illuminable portion of a key” refers generally to any or all areas of (or adjacent to) a keycap or other input surface that are intended to be illuminated such that the location, size, and/or functionality of that portion of the key is visually emphasized. 
     A glyph can be formed in an outer surface of a key from a translucent or transparent material to define an alphanumeric character, symbol, word, phrase, abbreviation, or any other linguistic, scientific, numeric, or pictographic symbol or set of symbols. In one example, the glyph itself illuminates upon activation of the light emitting element. In other examples, other portions of the key associated with the glyph illuminate upon activation of the light emitting element such as a glyph border, a glyph underline, a glyph outline, and so on. All are examples of illuminable portions of a key. 
     Another example of an illuminable portion of a key is the geometry of the key itself. In one example, the light emitting element illuminates a key perimeter. In other examples, other portions of the key geometry are illuminated, such as an external surface, a sidewall, a corner, and so on. In further examples, the light emitting element can illuminate spaces between one or more keys and the adjacent structure of a keyboard. For example, an aperture in which a key is disposed illuminates upon activation of the light emitting element, thereby generating a halo around a base of the key. 
     As noted above, the light emitting element optically couples to illuminable portions of a key via a light guide. In some embodiments, the light guide takes the shape of a ring, although such a shape is not required. The ring-shaped light guide can be fully closed or can be segmented. Such a light guide is formed from an optically translucent (or transparent) material. A body of the light guide can define an inner sidewall, an outer sidewall, a top endcap surface, and a bottom endcap surface. The light emitting element is optically coupled, either directly or indirectly, to the body of the light guide. The endcap surfaces are optically coupled, either directly or indirectly, to the illuminable portions of the key or keycap. 
     The sidewalls of the light guide exhibit greater internal reflection than the endcap surfaces. In one example, one or more prisms or scallops are formed in the sidewalls and are oriented to reflect light internally (e.g., into the interior of the light guide) whereas an endcap surface is smooth and facilitates transmission of light therethrough. In this manner, light emitted by the light emitting element exits the light guide in a greater quantity and in a more uniform manner through the endcap surfaces, and thus through the illuminable portions of the key, than from the sidewalls of the light guide. 
     In other embodiments, a light guide can form a structural portion of the key in addition to directing light. In these examples, the light guide also includes one or more internal reflectors (e.g., reflective surface), such as rectilinear through-holes, laser etched or routed channels, insert-molded reflectors, or the like. The internal reflectors are positioned and oriented to direct light (via internal reflection) within the body to selected locations of the top surface and/or the outer sidewall. In some cases, the internal reflectors are oriented oblique to a light emitting element. The internal reflectors direct light around structural features of the body that can cause light to undesirably scatter, leak, or exit the body away from the illuminable portion of the key (“light leakage”). In this manner, light emitted by the light emitting element exits the light guide in a greater quantity and in a more uniform manner through the top surface and/or the outer sidewall (which may, in some embodiments, be smooth and facilitate light transmission therethrough), and thus to the illuminable portion of the key, because less light is lost to leakage. 
     These and other embodiments are discussed below with reference to  FIGS. 1A-9 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1A  depicts an electronic device  100  incorporating a keyboard with illuminable keys, such as the illuminable key  102  depicted in a removed view of greater scale identified by the enclosed circle A-A, shown in  FIGS. 1A-1B . 
     The electronic device  100  is a portable laptop computer including an integrated keyboard with illuminable keys, such as an illuminable key  102  or other suitable input structure. The illuminable key  102  at least partially extends through an aperture  104  defined in a housing  106  of the electronic device  100 . The illuminable key  102  depresses at least partially into the aperture  104  when a user presses the illuminable key  102 . In one example, a top surface of the illuminable key  102  is flush with a top surface of the housing of the electronic device  100  when the illuminable key  102  is fully pressed. Other sample input structures may take the form of buttons, mice, trackpads, touch-sensitive surfaces, and so on. 
     A structure associated with the illuminable key  102  is disposed at least partially within the aperture  104 . This structure, referred to as a “key stack,” can include a keycap or similar input surface, a key mechanism, an elastomeric dome, a switch housing, and electronic switch circuitry. The keycap typically defines at least one illuminable portion, depicted in  FIG. 1A  as a glyph  108 . 
       FIG. 2A  depicts an example key mechanism that may be used with an illuminable key of the keyboard shown in  FIGS. 1A-1B  (or another suitable input structure). The key mechanism  200  is shown as a depressible mechanism and includes a first wing  202  and a second wing  204  that are coupled together with a hinge  206 . The first wing  202  and the second wing  204  are substantially symmetric across the hinge  206 . For example, as illustrated the first wing  202  and a second wing  204  are each formed in a U-shape, the free ends of which are coupled by the hinge  206  to form a closed ring. The key mechanism  200  is depicted in a depressed configuration (e.g., the key is pressed by a user). When the depressible mechanism depresses, the wings may flatten or otherwise move toward a base of the mechanism. 
     In many cases, the hinge  206  is a living hinge formed from a flexible material such as a polymer or elastomer. In other cases, the hinge  206  is a flexible member overmolded onto the first wing  202  and the second wing  204 . The flexible member can be formed from metal, fabric, polymer, or the like. In other embodiments, the first wing  202  and the second wing  204  can be formed from an optically translucent material and can be optically coupled to a light emitting element. In this manner, the first wing  202  and the second wing  204  can serve as a portion of a light guide. 
     Many embodiments include more than one hinge. For example, as depicted, the first wing  202  and the second wing  204  are joined by two hinges. 
     The first wing  202  and the second wing  204  are typically formed from the same material, although this is not required. For example, in one embodiment, the first wing  202  is formed from a plastic material doped with glass fibers and the second wing is formed from metal. In other embodiments, both the first wing  202  and the second wing  204  are formed from a doped plastic material. In one embodiment, the dopant material can be selected to increase the strength and/or rigidity of the first wing  202  and the second wing  204 . 
     Both the first wing  202  and the second wing  204  include geometry configured to interlock with one or more other structural portions of the key mechanism  200 . For example, the first wing  202  includes a keycap pivot  208   a  that interlocks with and/or slides within a portion of a keycap (or other such input surface) positioned above the depressible mechanism  200 . The first wing  202  also includes a structural pivot  208   b  that interlocks with and/or slides within a portion of a structural body  210 . Similarly, the second wing  204  includes a keycap pivot  212   a  that interlocks with and/or slides within a portion of the keycap. The second wing  204  also includes a structural pivot  212   b  that interlocks with and/or slides within a portion of the structural body  210 . 
     The structural body  210  is formed from a rigid material such as plastic or metal. As with the first wing  202  and the second wing  204 , the structural body  210  can be formed from a doped material. The structural body  210  can be formed from an optically transparent or translucent material although this is not required of all embodiments. In one example, the structural body  210  can be formed from an optically opaque material. In other embodiments, the structural body  210  can be formed from a translucent material that takes a particular color. 
     A light guide  214  is positioned within the structural body  210 . The light guide  214 , and as illustrated, is shaped as a closed ring, although such a configuration is not required. For example, the light guide  214  can take a square shape, a rectangular shape, a grid shape, or any other shape or combination of shapes. In still further examples, the light guide  214  is formed as a segmented shape, such as a segmented ring. 
     The light guide  214  is formed from an optically translucent or transparent material such as acrylic, glass, or plastic. In many examples, the light guide  214  is insert-molded into the structural body  210 . In other embodiments, the light guide  214  is co-molded with the structural body  210 . In still further examples, the light guide  214  is molded into a light guide cavity that is defined within the structural body  210 . 
     As noted above, the light guide  214  includes a body that defines an inner sidewall  214   a , an outer sidewall  214   b , a top endcap surface  214   c , and a bottom endcap surface (not visible in  FIG. 2A ). The inner sidewall  214   a  and the outer sidewall  214   b  of the light guide  214  exhibit greater internal reflection than the endcap surfaces, such as the top endcap surface  214   c . In this manner, light emitted into the light guide  214  by a light emitting element (see, e.g.,  FIG. 2B ) will exit the light guide  214  in a greater quantity and in a more uniform manner through the top endcap surface  214   c  than through any other portion of the light guide  214 . In some examples, the top endcap surface  214   c  is optically diffusive. 
     The light guide  214  is optically coupled, either directly or indirectly, to one or more illuminable portions of the key. In one example, the light guide  214  is optically coupled to the glyph  108  of the illuminable key  102  depicted in  FIGS. 1A-1B . With respect to the orientation shown in  FIG. 1B , the light guide  214  emits light toward the bottom left hand portion of the illuminable key  102 . For example, in place of a ring configuration such as depicted in  FIG. 2A , the top endcap surface  214   c  of the light guide  214  can take a circular shape, positioned in the leftmost corner of the structural body  210  so that the top endcap surface  214   c  is positioned substantially below the glyph  108  of the illuminable key  102  depicted in  FIGS. 1A-1B . For other glyphs taking other shapes, the light guide  214  can take a different shape. In this manner, the shape and size of the light guide  214  is selected based on the geometry of the illuminable portion to which the light guide  214  is optically coupled. 
     The light guide  214  can be disposed around an aperture defined in the structural body  210 . For example, in one embodiment the structural body  210  defines a through-hole  210   a . As illustrated, the through-hole  210   a  is circular, although this is not required and the through-hole can take other shapes. A compressible dome  216  is disposed within the through-hole  210   a . In some embodiments, the compressible dome  216  is formed from an elastomeric material (e.g., is an elastomeric dome), although this is not required. Likewise, the compressible or collapsible dome  216  may be formed from a transparent or translucent material. For example, the compressible dome  216  is formed from an optically opaque material. In other examples, the compressible dome is formed from an optically translucent material of a particular color (e.g., white). In some embodiments, the compressible/collapsible dome may be replaced by a different structure, including various mechanical, electrical, and/or electromechanical switches. Likewise, the dome may be replaced by a structure designed to provide a particular feedback or feel to the user as the key (or other input surface) is pressed. For example, the dome may be replaced by a spring, a bi-stable element, and so on. 
     In some embodiments, the compressible dome  216  extends a certain distance above a top surface of the structural body  210 . In other embodiments, the compressible dome  216  is flush with a top surface of the structural body  210 . 
     In many embodiments, a top surface  216   a  of the compressible or otherwise collapsible dome  216  interfaces with the underside of the keycap (or other such input surface) of the illuminable key. In one example, the underside of the keycap includes a projection that contacts the top surface  216   a  of the compressible dome  216 . In other cases, the underside of the keycap can include an indentation that receives the top surface  216   a  of the compressible dome  216 . The compressible dome  216  collapses into the through-hole  210   a  to activate the electronic switch circuitry associated with the illuminable key in response to a user press of the keycap. 
     For simplicity of illustration, the depressible mechanism  200  is depicted in a depressed configuration (e.g., when the key is pressed by a user), depicting the first wing  202  and the second wing  204  fully extended. In an upward configuration, the outermost portions of the first wing  202  and the second wing  204  extend above the structural body  210 , pivoting relative to one another and relative to the structural body  210  at the hinge  206 . 
       FIG. 2B  depicts a cross-section view of the key mechanism (e.g., sample input structure) of  FIG. 2A  taken along line B-B of  FIG. 2A . As depicted in  FIG. 2A , the first wing  202  and the second wing  204 , when coupled by the hinge(s), define an internal area in which the structural body  210  is positioned. The light guide  214  is disposed within a portion of the structural body  210 . As illustrated, the top endcap surface  214   c  is substantially flush with a top surface of the structural body  210 , although such a configuration is not required. For example, in some embodiments the top endcap surface  214   c  extends proud of the top surface of the structural body  210 . In other examples, the top endcap surface  214   c  is inset into the structural body  210 . 
     In some embodiments, the light guide  214  extends partially, but not entirely, through the structural body  210 . More particularly, a bottom endcap surface  214   d  of the light guide  214  mates with an internal portion of the structural body  210 . In other embodiments, the bottom endcap surface  214   d  can extend through the entire depth of the structural body  210 . 
     Although the bottom endcap surface  214   d  is illustrated as substantially parallel to the top endcap surface  214   c , such a configuration is not required. For example, the bottom endcap surface  214   d  can be oblique to the top endcap surface  214   c.    
     As noted above, the light guide  214  can include a body  214   e . The body  214   e  is optically coupled, either directly or indirectly, to a light emitting element  218 . As illustrated, the body  214   e  is optically coupled to the light emitting element  218  through the bottom endcap surface  214   d . In other embodiments, the light emitting element  218  can be optically coupled to the light guide  214  at a different location. In other examples, the light emitting element  218  can be optically coupled to the light guide  214  indirectly, such as via a light pipe. 
     The light emitting element  218  includes one or more light-emitting diodes. The light-emitting diodes emit light of a particular color and at a particular brightness. In some embodiments, the light emitting element  218  provides light of a variable color or a variable brightness. In one example, the light emitting element  218  emits white light having a cool color temperature, although this is not required. 
     An electrical switch layer  220  is also depicted in  FIG. 2B . The electrical switch layer  220  is disposed below the compressible or otherwise collapsible dome  216  such that an electrical property of the electrical switch layer  220  changes when the compressible dome  216  compresses. In one example, the compressible dome  216  can complete an electrical contact between electrical traces or contacts disposed on the electrical switch layer  220  when the compressible dome  216  is compressed. The electrical traces are organized in an interleaved comb pattern or a concentric circular pattern. In other embodiments, the compressible dome  216  can cause a change in a capacitance measured between one or more portions of the electrical switch layer  220  when the compressible dome  216  compresses (or, put another way, a collapsible dome collapses). 
     The key mechanism  200  (or another example of a depressible mechanism) is disposed onto a substrate  222 . The substrate  222  can be positioned within a housing of an electronic device, such as the electronic device  100  depicted in  FIGS. 1A-1B . In other embodiments, the substrate  222  can be positioned within an aperture defined by the housing of an electronic device. In one example, the substrate  222  is formed from a rigid material such as metal or plastic. 
     As noted with respect to other embodiments described herein, the inner sidewall  214   a  and the outer sidewall  214   b  of the light guide  214  exhibit greater internal reflection than the top endcap surface  214   c  and the bottom endcap surface  214   d . More particularly, the internal reflection of light vectored toward a sidewall of the light guide  214  may be greater than the internal reflection of light vectored toward an endcap of the light guide. In an alternate and non-limiting phrasing, the sidewalls of the light guide  214  may be more optically reflective than the endcaps of the light guide  214 . 
     As may be appreciated, the reflectivity of a surface may depend upon the angle of incidence with which light strikes the surface and the difference between the refractive indices of the materials interfacing at the surface. More specifically, at the boundary between the light guide  214  and another material (e.g., air, the structural body  210 , the keycap, and so on) having a lower refractive index than that of the light guide  214 , light within the light guide  214  may be reflected internally. If the angle of incidence of the light is sufficiently high, total internal reflection may occur (e.g., almost zero light passes through the boundary; effectively all light reflects back into the body  214   e ). Thus, in some cases, the inner sidewall  214   a  and the outer sidewall  214   b  can exhibit total internal reflection. In some embodiments, the bottom endcap surface  214   d  may also exhibit greater internal reflection than the top endcap surface  214   c.    
     For these embodiments, most of the light emitted into the light guide  214  by the light emitting element  218  will either reflect off the inner sidewall  214   a  and/or the outer sidewall  214   b  (and/or the bottom endcap surface  214   d ), or will exit the light guide  214  through the top endcap surface  214   c . Similarly, for ring-shaped light guides, internal reflection of light can cause light to be emitted in a substantially uniform manner across the entire surface of the top endcap surface  214   c . More specifically, the portion of the top endcap surface  214   c  that is diametrically opposite the light emitting element  218  (e.g., the farthest point away from the light emitting element  218 , as illustrated in  FIG. 2A ) can emit a quantity of light substantially similar to the other portions of the top endcap surface  214   c . In this manner, the light guide  214  facilitates substantially uniform emission of light from its body. 
     As a result, the illuminable portions of the key to which the light guide  214  is optically coupled (either directly or indirectly) are illuminated in a substantially uniform manner. Likewise, other suitable input structures may be illuminated in this fashion. 
       FIG. 3  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , showing another example light guide. As with the embodiment depicted in  FIG. 2A , a light guide  314  can be disposed at least partially within a structural body  312  of a key mechanism  300 , or other depressible mechanism. The light guide  314  is optically coupled, either directly or indirectly, to a light emitting element  318 . The light emitting element  318  is positioned to emit light into a sidewall (e.g., outer sidewall) of the light guide  314 . A reflective feature  312   a  of the structural body  312  is positioned adjacent to and/or within the light emission path of the light emitting element  318 . 
     In many embodiments, the reflective feature  312   a  is a substantially flat surface that is oblique to the light emitting element  318 . In one embodiment, the reflective feature  312   a  is oriented toward a top endcap surface  314   c  of the light guide  314  at a 45-degree angle to the light emitting element  318 . The reflective feature  312   a  can be coated with a reflective coating such as a metalized ink. 
     The angle of the reflective feature  312   a  can be selected, at least in part, to increase or maximize the total internal reflection of light emitting from the light emitting element  318 . In such an embodiment, the structural body  312  and the light guide  314  can be formed from materials having different refractive indices. More particularly, the structural body  312  may have a lower refractive index n 2  than the refractive index n 1  of the light guide  314 . Once the refractive indices of the structural body  312  and the light guide  314  are known, an incident angle θ i  at which total internal reflection occurs (the “critical angle”) can be determined by the following equation:
 
θ i =arcsin( n   2   /n   1 )  Equation 1
 
     Once the incident angle θ i  is determined, the minimum angle of the reflective feature  312   a  can be determined. In this manner, the amount of light lost to absorption within the structural body  312  is substantially reduced. In other words, the volume of light that exits the top endcap surface  315   c  is increased. 
     In some embodiments, the reflective feature  312   a  can be implemented as a chamfer formed in the inner sidewall of the light guide. In other embodiments, the reflective feature  312   a  is a non-flat surface such as a convex surface, a concave surface, or a domed surface. 
     In other embodiments, the light emitting element  318  is positioned elsewhere. For example, in one embodiment, the light emitting element  318  is optically coupled to an internal sidewall of the light guide. In other embodiments, such as depicted in  FIG. 2B , the light emitting element  318  is coupled to a bottom surface (e.g., bottom endcap surface) of the light guide. In still other embodiments, the light emitting element  318  is optically coupled to the top endcap surface  314   c  of the light guide  314 . In these and related embodiments, one or more reflective features, such as the reflective feature  312   a , can be formed within the structural body  312  to direct light emitted from the light emitting element  318  in a particular direction. 
       FIG. 4  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , showing another example light guide. As with the embodiment depicted in  FIG. 2A , a light guide  414  can be disposed at least partially within a structural body  412  of a key mechanism  400 . The light guide  414  is optically coupled, either directly or indirectly, to a light emitting element  418 . 
     As with the embodiment depicted in  FIG. 3 , the light emitting element  418  is positioned to emit light into a sidewall (e.g., outer sidewall) of the light guide  414 . A first reflective feature  412   a  and a second reflective feature  412   b  of the structural body  412  are positioned adjacent to the light emitting element  418 . In many embodiments, the reflective features  412   a ,  412   b  are substantially flat surfaces that are oriented oblique to the light emitting element  418 . In one embodiment, the reflective feature  412   a  is angled toward a top endcap surface  414   c  of the light guide  414  at a 45-degree angle to the light emitting element  418 . The reflective feature  412   a  can be coated with a reflective coating such as a metalized ink. In other examples, the angle of the reflective feature  412   a  is selected, at least in part, to maximize the total internal reflection of light emitting from the light emitting element  418 . 
     As with the embodiment depicted in  FIG. 3 , Equation 1 may be used to determine or approximate the angle(s) of the reflective features  412   a ,  412   b.    
       FIG. 5  depicts a cross-section view of the key mechanism of  FIG. 2A  taken along line B-B of  FIG. 2A , showing another example light guide. As with the embodiment depicted in  FIG. 2A , a light guide  514  can be disposed at least partially within a structural body  512  of a key mechanism  500 . The light guide  514  is optically coupled, either directly or indirectly, to a light emitting element  518 . In the illustrated embodiment, the light guide  514  can include a partially domed surface, identified as the top endcap surface  514   c.    
     It may be appreciated that the embodiments depicted in  FIGS. 2B and 3-5  are not exhaustive. For example, in some embodiments, the various features depicted in  FIG. 5  can be incorporated into an embodiment incorporating features depicted and described with respect to  FIG. 3 . Other embodiments can include additional reflective surfaces other than those shown. For example, as noted above, many embodiments described herein employ a light guide with its sidewalls formed to exhibit greater internal reflection than its endcap surfaces. 
       FIG. 6A  depicts an example ring-shaped light guide  600  having an external prismatic sidewall  602  and an internal prismatic sidewall  604 . The external prismatic sidewall  602  and the internal prismatic sidewall  604  exhibit a repeating pattern of triangular prisms. In some embodiments, the depth of the external prismatic sidewall  602  and the internal prismatic sidewall  604  can be varied, such as shown in  FIG. 6B . In other embodiments, the number of triangular prisms can be varied, such as shown in  FIG. 6C . In other embodiments, the shape of the prisms can be changed. For example, as shown in  FIG. 6D , the external prismatic sidewall  602  can take a saw tooth (e.g., serrated) shape. In such an embodiment, the internal prismatic sidewall  604  can also take a saw tooth shape. In some cases, the internal prismatic sidewall  604  can be oriented oppositely from the external prismatic sidewall  602 . In this manner, light within the ring-shaped light guide  600  can be directed in a substantially counterclockwise direction. 
     As with other embodiments described herein, the geometry of the prismatic sidewalls of a light guide can be determined or approximated, at least in part, based on the refractive index of the material selected for the light guide. 
     In other embodiments, the sidewalls of the light guides can take other shapes. For example, in some embodiments, such as depicted in  FIGS. 6E-6F , a ring-shaped light guide  600  can include scalloped sidewalls. As with prismatic sidewalls depicted in  FIGS. 6A-6D , the scalloped sidewalls  606 ,  608  can take any number of specific shapes. For example, the depth, size, width, radius, and orientation of the scallops can vary from embodiment to embodiment. 
     As noted above, in other embodiments, a light guide of an illuminable key can form a portion of the structure of the key itself. For example,  FIG. 7A  depicts an example light guide that serves a dual purpose of directing light to an illuminable portion of a key and providing structural support to one or more portions of the key. The light guide  700  can take the shape of a structural body, such as the structural body  210  depicted in  FIGS. 2A-2B . The light guide  700  includes a through-hole  702 . A compressible dome, such as the compressible dome  216  depicted in  FIGS. 2A-2B  can be inserted into the through-hole  702 . A light emitting element  706  is disposed at one corner of the light guide  700  to emit light into the light guide  700 . 
     As with other embodiments described herein, the light guide  700  is made from an optically translucent or transparent material such as plastic, glass, doped plastic or glass, sapphire, zirconia or the like. The light guide  700  is formed from a material with a known or determinable refractive index. 
     In other embodiments, the light emitting element  706  can be disposed in other locations along the light guide  700 . In one embodiment, more than one light emitting element can be used. For example,  FIG. 7B  depicts an embodiment with two light emitting elements, each labeled as a light emitting element  706 . 
     The through-hole  702  can have a greater internal reflectance than other surfaces of the light guide  700 . For example, the through-hole  702  can include a prismatic sidewall, such as shown and described with respect to  FIGS. 6A-6D  and as illustrated in  FIGS. 7A-7C . In other embodiments, the through-hole  702  can include a scalloped sidewall, such as shown and described with respect to  FIGS. 6E-6F . 
     In still further examples, the light guide  700  can include an internally reflective feature  708 . In one embodiment, the internally reflective feature  708  can be implemented as a rectilinear through-hole, a laser etched or routed channel, an insert-molded reflector, or the like. For example, as shown in  FIG. 7C , three internally-reflective features are depicted, positioned and oriented to direct light (via internal reflection) within the body of the light guide  700 . In this manner, the internally reflective features direct light around structural features of the body, such as the through-hole  702 . Although the internally reflective features  708  are depicted as rotated at 45 degrees, one may appreciate that different embodiments can orient the internally reflective feature  708  at different angles. 
       FIG. 8  is a flow chart depicting operations of a method of manufacturing a light guide. The method can begin at operation  800  in which a light guide is insert-molded into a structural base of a key stack. Next, at operation  802 , a light emitter, such as a light-emitting diode, is positioned in optical communication with the light guide. 
       FIG. 9  is a flow chart depicting operations of a method of manufacturing a light guide based on a selected glyph. The method begins at operation  900  at which a glyph is selected. Next at operation  902 , the light guide and/or key structure are formed based on the shape and location of the selected glyph (or glyphs). 
     Although many embodiments described and depicted herein reference light guides for illuminable keys of a keyboard, it should be appreciated that other implementations can take other form factors. Thus, the various embodiments described herein, as well as functionality, operation, components, and capabilities thereof may be combined with other elements as necessary, and so any physical, functional, or operational discussion of any element or feature is not intended to be limited solely to a particular embodiment to the exclusion of others. 
     For example, although the electronic device  100  is shown in  FIGS. 1A-1B  as a laptop computer, it may be appreciated that other electronic devices are contemplated. For example, the electronic device  100  can be implemented as a peripheral input device, a desktop computing device, a handheld input device, a tablet computing device, a cellular phone, a wearable device, and so on. 
     Further, it may be appreciated that the electronic device  100  can include one or more components that interface or interoperate, either directly or indirectly, with the illuminable key  102  which, for simplicity of illustration are not depicted in  FIGS. 1A-1B . For example, the electronic device  100  may include a processor coupled to or in communication with a memory, a power supply, one or more sensors, one or more communication interfaces, and one or more input/output devices such as a display, a speaker, a rotary input device, a microphone, an on/off button, a mute button, a biometric sensor, a camera, a force and/or touch sensitive trackpad, and so on. 
     In some embodiments, the communication interfaces provide electronic communications between the electronic device  100  and an external communication network, device or platform. The communication interfaces can be implemented as wireless interfaces, Bluetooth interfaces, universal serial bus interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communications interfaces, or any conventional communication interfaces. The electronic device  100  may provide information related to externally connected or communicating devices and/or software executing on such devices, messages, video, operating commands, and so forth (and may receive any of the foregoing from an external device), in addition to communications. As noted above, for simplicity of illustration, the electronic device  100  is depicted in  FIGS. 1A-1B  without many of these elements, each of which may be included, partially, optionally, or entirely, within a housing  106 . 
     In some embodiments, the housing  106  can be configured to, at least partially, surround a display. In many examples, the display may incorporate an input device configured to receive touch input, force input, and the like and/or may be configured to output information to a user. The display can be implemented with any suitable technology, including, but not limited to, a multi-touch or multi-force sensing touchscreen that uses liquid crystal display (LCD) technology, light-emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. 
     The housing  106  can form an outer surface or partial outer surface and protective case for the internal components of the electronic device  100 . In the illustrated embodiment, the housing  106  is formed in a substantially rectangular shape, although this configuration is not required. The housing  106  can be formed of one or more components operably connected together, such as a front piece and a back piece or a top clamshell and a bottom clamshell. Alternatively, the housing  106  can be formed of a single piece (e.g., uniform body or unibody). 
     Various embodiments described herein can be incorporated with other systems or apparatuses and may not, in all cases, be directly associated with an input device configured for use with an electronic device such as depicted in  FIGS. 1A-1B . For example, a light guide as described herein can be incorporated into an independent electronic switch such as a button (e.g., light switch, automotive button, doorbell, and so on). In other examples, a light guide as described herein can be incorporated into a different portion of an electronic device, such as a display element of an electronic device. In such an example, a light guide incorporating prismatic or scalloped sidewalls can be used as a backlight diffuser within a display stack-up. 
     Additionally, it may be appreciated that for illuminable key embodiments the various structures and mechanisms described herein are not intended to limit the disclosure to a particular favored or required geometry or form factor. For example, an illuminable key can include a butterfly mechanism, a scissor mechanism, or any other suitable type of key mechanism. An illuminable key can include a keycap that is formed to have a substantially flat top surface or, in other embodiments, to have a partially curved top surface. An electronic switch associated with the illuminable key can be implemented as a single throw switch, a multi-throw switch, a capacitive switch, and so on. A tactile feedback structure associated with the illuminable key can be implemented as an elastomeric dome, a spring, an elastomer deposit, a metal dome, or any combination thereof. 
     Furthermore, one may appreciate that although many embodiments are disclosed above, that the operations and steps presented with respect to methods and techniques described herein are meant as exemplary and accordingly are not exhaustive. One may further appreciate that an alternate step order or fewer or additional steps may be implemented in particular embodiments. 
     Although the disclosure above is described in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the some embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments but is instead defined by the claims herein presented.

Metadata:
Filing Date: 20160513
Publication Date: 20180612
Grant Date: 20180612
Priority Date: 20150513
Inventors: LEONG, Craig C.
ZERCOE, BRADFORD J.
MATHEW, DINESH C.
KRISHNAMURTHI, Mahesh
CAO, ROBERT Y.
QI, JUN
LIU, RONG
YIN, VICTOR H.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H2219/0622", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/023", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/0622", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/023", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2219/0622", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 56411876