# US 7,407,315 B2 · Method and apparatus for backlighting a device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,315 B2 - Document ID: US7407315B2 - Status: Granted - Kind: B2 - Application number: 11/172,225 - Filed: 2005-06-29 - Published: 2005-11-17 - Granted: 2008-08-05 - Earliest claimed: 2003-07-17 - Assignees: Apple Inc. - Inventors: Steven Porter Hotelling - Web page: https://patentgrep.com/patent/US7407315B2 ## CPC - G02B 6/0018: {Redirecting means on the surface of the light guide} - G02B 6/0021: {for housing at least a part of the light source, e.g. by forming holes or recesses} - Y10S 362/80: Light emitting diode - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A light guide panel is disclosed. The panel comprises a plate for dispersing light and at least one light-emitting diode (LED) coupled to the plate for providing the dispersed light. When the panel is coupled to a keyboard, the at least one LED is under a portion of the keyboard such that when the at least one LED is illuminated, the light from the LED does not distract a user. Accordingly, by strategically placing LEDs within the panel and providing the LEDs under appropriate portions of the keyboard, the device utilizing the keyboard can be smaller than when a conventional light guide panel is utilized. In addition, a further improvement in illumination is provided when a mechanism is provided which reflects light escaping from the edges of the panel back into the panel. ## Claims ### Claim 1 A light guide panel for backlighting a device, the light guide panel comprising: a plate including a plurality of optical fibers for dispersing light through the plate to illuminate the plate and provide a backlight for the device, the plurality of optical fibers being completely within the plate; and a light-emitting diode (LED) coupled to the plate for providing the light dispersed by the plurality of optical fibers, the light-emitting diode being located in a central portion of the plate such that the light-emitting diode (LED) does not touch an edge of the plate, wherein an opaque portion of the device covers the light-emitting diode (LED) in the central portion of the plate such that when the light-emitting diode (LED) is illuminated, the light from the light-emitting diode (LED) is more evenly distributed throughout the plate, the opaque portion of the device being a user input button of the device. ### Claim 2 (depends on 1) The light guide panel of claim 1, wherein the light guide panel comprises a plurality of light-emitting diodes (LEDs) coupled to the plate. ### Claim 3 (depends on 2) The light guide panel of claim 2, wherein the plurality of light-emitting diodes (LEDs) are coupled to the device to provide for even distribution of light throughout the plate. ### Claim 4 (depends on 1) The light guide panel of claim 1, further comprising a mechanism to reflect light at an edge of the plate back into the plate. ### Claim 5 (depends on 4) The light guide panel of claim 4, wherein the mechanism comprises jagged ends on an edge of the plate. ### Claim 6 (depends on 1) The light guide panel of claim 1, wherein: the device is a keyboard; and the opaque portion of the device comprises a keypad on the keyboard. ### Claim 7 (depends on 4) The light guide panel of claim 4, wherein the mechanism comprises sheet metal flanges that are parallel to an edge of the plate. ### Claim 8 An assembly comprising: a device; and a light guide panel coupled to the device for providing a backlight for the device, the light guide panel comprising, a plate including a plurality of optical fibers for dispersing light through the plate to illuminate the plate, the plurality of optical fibers being completely within the plate; and a light-emitting diode (LED) coupled to the plate for providing the light dispersed by the plurality of optical fibers, the light-emitting diode being located in a central portion of the plate such that the light-emitting diode (LED) does not touch an edge of the plate; and wherein an opaque portion of the device covers the light-emitting diode (LED) in the central portion of the plate such that when the light-emitting diode (LED) is illuminated, the light from the light-emitting diode (LED) is more evenly distributed throughout the plate, the opaque portion of the device being a user input button of the device. ### Claim 9 (depends on 8) The assembly of claim 8, wherein the plate comprises a clear sheet of material with a printed dot pattern for further dispersing light through the plate. ### Claim 10 (depends on 8) The assembly of claim 8, wherein the light guide panel comprises a plurality of light-emitting diodes (LEDs) coupled to the plate. ### Claim 11 (depends on 10) The assembly of claim 10, wherein the plurality of light-emitting diodes (LEDs) are coupled to the device to provide for even distribution of light throughout the plate. ### Claim 12 (depends on 8) The assembly of claim 8, wherein the plate includes a mechanism to reflect light at an edge of the plate back into the plate. ### Claim 13 (depends on 12) The assembly of claim 12, wherein the mechanism comprises jagged ends on an edge of the plate. ### Claim 14 A light guide panel for backlighting a device, the light guide panel comprising: a plate including a plurality of optical fibers for dispersing light through the plate to illuminate the plate and provide a backlight for the device, the plurality of optical fibers completely within the plate, the plate including a mechanism to reflect light at an edge of the plate back into the plate; and a plurality of light-emitting diodes (LEDs) coupled to the plate for providing the light dispersed by the plurality of optical fibers, each of the plurality of light-emitting diode being located in a central portion of the plate such that each light-emitting diode (LED) does not touch an edge of the plate, wherein opaque portions of the device respectively covers each light-emitting diode (LED) in the central portion of the plate, such that when each of the plurality of light-emitting diodes (LEDs) are illuminated, the light from the plurality of light-emitting diodes (LEDs) is more evenly distributed throughout the plate, the opaque portions of the device being user input buttons of the device. ### Claim 15 (depends on 14) The light guide panel of claim 14, wherein each of the opaque portions of the device is a user input button of the device. ### Claim 16 (depends on 14) The light guide panel of claim 14, wherein the mechanism comprises jagged ends on an edge of the plate. ### Claim 17 A light guide panel for backlighting a keyboard, the light guide panel comprising: a plate including a plurality of optical fibers for dispersing light through the plate to illuminate the plate and provide a backlight for the keyboard, the plurality of optical fibers being completely within the plate, the plate further including a mechanism to reflect light at an edge of the plate back into the plate; and a light-emitting diode (LED) coupled to the plate for providing the light dispersed by the plurality of optical fibers, the light-emitting diode being located in a central portion of the plate such that the light-emitting diode (LED) does not touch an edge of the plate, wherein a keypad of the keyboard covering the light-emitting diode (LED) in the central portion of the plate such that when the light-emitting diode (LED) is illuminated, the light from the light-emitting diode (LED) is more evenly distributed throughout the plate. ### Claim 18 (depends on 17) The light guide panel of claim 17, wherein the mechanism comprises jagged ends on an edge of the plate.