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Researchers Submit Patent Application, "Display Backlight with Closely Spaced Light-Emitting Diode Packages", for Approval

February 26, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Doyle, David A. (San Francisco, CA); Gettemy, Shawn R. (San Jose, CA), filed on August 7, 2012, was made available online on February 13, 2014.

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "This relates generally to electronic devices, and more particularly, to electronic devices with displays.

"Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user. An electronic device may have a housing such as a housing formed from plastic or metal. Components for the electronic device such as display components may be mounted in the housing.

"It can be challenging to incorporate a display into the housing of an electronic device. Size and weight are often important considerations in designing electronic devices. If care is not taken, displays may be bulky or may be surrounded by overly large borders.

"It would therefore be desirable to be able to provide improved backlit displays for electronic devices."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An electronic device may be provided with a display that has display layers such as a layer of liquid crystal material interposed between a color filter layer and a thin-film-transistor layer. The color filter layer, liquid crystal layer, and thin-film transistor layer may be interposed between upper and lower polarizers.

"Backlight structures may be used to provide backlight that passes through the display layers. The backlight structures may include a light guide plate formed from injection molded plastic or a clear polymer film. The light guide plate may have an edge into which light is emitted from an adjacent array of light-emitting diodes.

"The light emitting diodes may each include a semiconductor device that emits light. The semiconductor device in each diode may be mounted on lead frame structures in a molded plastic package or may be formed as a portion of a chip-on-board package with attached light redirecting structures.

"In configurations in which the semiconductor device is mounted on lead frame structures, the semiconductor device may be electrically connected to the lead frame structures using first and second wire bonds or using solder bumps on a bottom surface of the semiconductor device.

"In configurations in which the semiconductor device is formed as a portion of a chip-on-board package with attached light redirecting structures, the attached light redirecting structures may be attached to a substrate using adhesive. The attached light redirecting structures may include ceramic, metal, plastic, or resin wall structures that at least partially surround the semiconductor device. In this type of configuration, the semiconductor device may be electrically connected to the electrical contacts on the substrate using wire bonds.

"Light from each diode may be emitted through a window in the molded plastic package or the chip-on-board package. The window may occupy a relatively large portion of the front face of a package and may contain a phosphorescent filler material.

"To improve backlight homogeneity and thereby reduce the mixing distance for light in the light guide plate, the diodes may be spaced closely together using diode packages having end faces that are free of lead frame structures. Lead frame structures for the light-emitting diodes may be formed under the light-emitting diodes and on rear surfaces of the light-emitting diodes. The exposed lead frame structures may be soldered to solder pads on a dielectric substrate.

"Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 is a perspective view of an illustrative electronic device such as a laptop computer with a display in accordance with an embodiment of the present invention.

"FIG. 2 is a perspective view of an illustrative electronic device such as a handheld electronic device with a display in accordance with an embodiment of the present invention.

"FIG. 3 is a perspective view of an illustrative electronic device such as a tablet computer with a display in accordance with an embodiment of the present invention.

"FIG. 4 is a schematic diagram of an illustrative electronic device with a display in accordance with an embodiment of the present invention.

"FIG. 5 is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention.

"FIG. 6 is a top view of backlight structures for a display in accordance with an embodiment of the present invention.

"FIG. 7 is a cross-sectional side view of an illustrative light guide plate and an associated light-emitting diode that is injecting light into an edge of the light guide plate in accordance with an embodiment of the present invention.

"FIG. 8 is a front view of an illustrative packaged light-emitting diode in accordance with an embodiment of the present invention.

"FIG. 9 is a top view of an illustrative light guide plate and an associated array of light-emitting diodes for providing backlight in a display in accordance with an embodiment of the present invention.

"FIG. 10 is a top view of a portion of a light guide plate showing how reduced diode-to-diode spacing in an array of light-emitting diodes may help minimize mixing distance in the light guide plate in accordance with an embodiment of the present invention.

"FIG. 11 is a rear perspective view of an illustrative packaged light-emitting diode showing how lead frame terminals may be wrapped under and around the back of a light-emitting diode to allow the light-emitting diode to be mounted close to another light-emitting diode in an array of light-emitting diodes of the type shown in FIG. 10 in accordance with an embodiment of the present invention.

"FIGS. 12, 13, and 14 are perspective views of illustrative lead frame configurations that may be used in forming a packaged light-emitting diode of the type shown in FIG. 11 in accordance with an embodiment of the present invention.

"FIG. 15 is a flow chart of illustrative steps involved in forming an electronic device having display backlight structures in accordance with an embodiment of the present invention.

"FIG. 16 is a perspective view of an illustrative lead frame configuration that may be used in forming a packaged light-emitting diode of the type shown in FIG. 11 in accordance with an embodiment of the present invention.

"FIG. 17 is a rear perspective view of an illustrative packaged light-emitting diode showing how electrical contacts may be formed on a rear surface of a chip-on-board package to allow the light-emitting diode to be mounted close to another light-emitting diode in an array of light-emitting diodes of the type shown in FIG. 10 in accordance with an embodiment of the present invention.

"FIG. 18 is a cross-sectional side view of a chip-on-board package of the type shown in FIG. 17 in accordance with an embodiment of the present invention."

For additional information on this patent application, see: Doyle, David A.; Gettemy, Shawn R. Display Backlight with Closely Spaced Light-Emitting Diode Packages. Filed August 7, 2012 and posted February 13, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4887&p=98&f=G&l=50&d=PG01&S1=20140206.PD.&OS=PD/20140206&RS=PD/20140206

Keywords for this news article include: Patents, Electronics, Semiconductor, Light-emitting Diode.

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Source: Electronics Newsweekly


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