Patent 8408778

Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

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Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

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To identify the most relevant prior art for US patent 8408778, I will examine the "Patent Citations (21)" section provided in the patent text. For each listed patent, I will provide the full citation, publication/filing date, a brief description, and discuss which claims (specifically independent claims 1, 20, and 23 of US8408778) it potentially anticipates under 35 U.S.C. § 102.

Independent Claims of US8408778 for reference:

  • Claim 1 (Light Source): Comprises a light guide plate (LGP); at least one light emitting module (LEDs) emitting light to a side of the LGP; an optical sheet (diffusion + prism) on the LGP; and a conversion sheet on the top surface of the optical sheet. The conversion sheet converts the color of light after it passes through the diffusion and prism sheets.
  • Claim 20 (Display Device): Comprises a cover; an LED module on the cover; an LGP at a side of the LED module; an optical sheet (diffusion + prism) on the LGP; a display panel on the optical sheet; and a conversion layer between the optical sheet and the display panel. The conversion layer converts the first color of light emitted by the LGP to a target color, and converts the color of light passing through the diffusion and prism sheets.
  • Claim 23 (Light Source): Similar to Claim 1, but includes a reflective plate under the LGP. The optical sheet includes a diffusion sheet with a prism sheet on it. Critically, the conversion sheet is coated with a color coordinate material on an upper surface of the diffusion sheet such that it converts the color of light diffusing by the diffusion sheet.

Analysis of Cited Prior Art for US8408778:

Here's an analysis of the cited prior art, extracted from the provided patent document:

  1. KR19980065685U

    • Full Citation: KR19980065685U, "LCD Display," Son Uk.
    • Publication/Filing Date: Priority Date: 1997-05-06, Publication Date: 1998-12-05.
    • Brief Description: The title suggests a general LCD display. Without an abstract, specific details about color conversion or light guide configurations are unknown.
    • Potential Anticipation: Unclear without further details on its internal structure and light modification features. Given its early publication date, it's less likely to anticipate the specific color conversion sheet/layer features of US8408778.

  2. US20080067536A1

    • Full Citation: US20080067536A1, "Image display device and light emission device," Kabushiki Kaisha Toshiba.
    • Publication/Filing Date: Priority Date: 1997-05-16, Publication Date: 2008-03-20.
    • Brief Description: Describes an image display device and light emission device. Without an abstract, specific details regarding color conversion sheets are not immediately apparent.
    • Potential Anticipation: Similar to KR19980065685U, more information is needed to determine anticipation of the specific color conversion features.

  3. US5982092A

    • Full Citation: US5982092A, "Light Emitting Diode planar light source with blue light or ultraviolet ray-emitting luminescent crystal with optional UV filter," Chen; Hsing.
    • Publication/Filing Date: Priority Date: 1997-10-06, Publication Date: 1999-11-09.
    • Brief Description: This patent describes an LED planar light source that uses a blue light or UV-emitting luminescent crystal, possibly with a UV filter. The mention of "luminescent crystal" suggests a phosphor-like material for color conversion.
    • Potential Anticipation: This patent potentially anticipates the concept of using luminescent (fluorescent) material for color conversion from LEDs. If the luminescent crystal acts as a layer or sheet in a light guide arrangement, it could potentially anticipate the "conversion sheet/layer" aspect of claims 1, 20, and 23, especially the use of fluorescent material for color change.

  4. JP2000133006A

    • Full Citation: JP2000133006A, "Surface light source," Sanyo Electric Co Ltd.
    • Publication/Filing Date: Priority Date: 1998-10-29, Publication Date: 2000-05-12.
    • Brief Description: The title "Surface light source" indicates a backlight type device. Specifics on color conversion are not clear from the title.
    • Potential Anticipation: Needs further review of its detailed description for elements related to color conversion sheets and their placement in relation to optical sheets and light guide plates.

  5. US20070090383A1

    • Full Citation: US20070090383A1, "Light emitting device," Toyoda Gosei Co., Ltd.
    • Publication/Filing Date: Priority Date: 2000-12-28, Publication Date: 2007-04-26.
    • Brief Description: Describes a light-emitting device. The title is broad.
    • Potential Anticipation: Requires detailed examination of its content to determine if it discloses a light guide plate, LED module, optical sheets (diffusion/prism), and a specific color conversion sheet arrangement as claimed in US8408778.

  6. JP2003222861A

    • Full Citation: JP2003222861A, "Phosphor chromaticity correction plate," Citizen Electronics Co Ltd.
    • Publication/Filing Date: Priority Date: 2002-01-29, Publication Date: 2003-08-08.
    • Brief Description: This patent explicitly mentions a "Phosphor chromaticity correction plate," strongly suggesting a component similar to the "color coordinate conversion sheet" of US8408778. "Chromaticity correction" directly relates to color conversion.
    • Potential Anticipation: This is a highly relevant reference. It potentially anticipates the concept of a color conversion layer/sheet (specifically using phosphor) to adjust the chromaticity (color coordinate distribution) of light. If this plate is used in a backlight unit with an LGP, LED module, and optical sheets in a configuration similar to US8408778, it could potentially anticipate claims 1, 20, and 23.

  7. JP2003279985A

    • Full Citation: JP2003279985A, "Liquid crystal display," Kyocera Corp.
    • Publication/Filing Date: Priority Date: 2002-03-26, Publication Date: 2003-10-02.
    • Brief Description: Describes a liquid crystal display.
    • Potential Anticipation: The general title doesn't reveal direct anticipation of the specific color conversion sheet. Further review of its content is necessary.

  8. US20040090161A1

    • Full Citation: US20040090161A1, "Method for manufacturing a light emitting device," Citizen Electronics Co., Ltd.
    • Publication/Filing Date: Priority Date: 2002-09-26, Publication Date: 2004-05-13.
    • Brief Description: Focuses on a method for manufacturing a light-emitting device.
    • Potential Anticipation: While it might describe components of a light-emitting device, its primary focus on manufacturing might not directly anticipate the structural claims (1, 20, 23) of US8408778 unless the manufactured device inherently possesses the claimed structure.

  9. US20040207995A1

    • Full Citation: US20040207995A1, "Light unit for display device," Park Jong Hwa.
    • Publication/Filing Date: Priority Date: 2003-04-18, Publication Date: 2004-10-21.
    • Brief Description: Describes a "light unit for display device," which is a backlight assembly. This could be relevant for the general structure of a light source in a display.
    • Potential Anticipation: This patent could be relevant to the general elements of a light source (LGP, LEDs, optical sheets). Specifics regarding a color conversion sheet for fine-tuning LED "multi-ranks" would need to be checked.

  10. US7350937B2

    • Full Citation: US7350937B2, "Lighting unit, lighting module, and liquid crystal display," Hitachi Displays, Ltd.
    • Publication/Filing Date: Priority Date: 2004-05-25, Publication Date: 2008-04-01.
    • Brief Description: Describes a lighting unit, lighting module, and LCD. This is directly relevant to the subject matter of US8408778.
    • Potential Anticipation: This patent is likely highly relevant. It could potentially anticipate the arrangement of LGP, LED module, optical sheets, and possibly some form of color control within the lighting unit. A detailed review of its claims and description is needed to determine if it discloses a color conversion sheet with specific placement and function for managing LED color coordinates, especially "multi-rank" LEDs.

  11. US20060001036A1

    • Full Citation: US20060001036A1, "LED-based edge lit illumination system," Gelcore, Llc.
    • Publication/Filing Date: Priority Date: 2004-07-02, Publication Date: 2006-01-05.
    • Brief Description: This patent describes an LED-based edge-lit illumination system. This is a common configuration for LCD backlights, aligning with the "light emitting module positioned so as to emit light incident on the light guide plate" in US8408778.
    • Potential Anticipation: It could anticipate the general structural elements of an edge-lit light source (LGP, edge-mounted LEDs). However, specific color conversion features (e.g., a conversion sheet on top of optical sheets for multi-rank LEDs) would need to be present to anticipate claims 1, 20, and 23.

  12. US20060268537A1 (Kurihara)

    • Full Citation: US20060268537A1, "Phosphor film, lighting device using the same, and display device," Makoto Kurihara.
    • Publication/Filing Date: Priority Date: 2005-05-31, Publication Date: 2006-11-30.
    • Brief Description: This patent specifically discloses a "phosphor film" and a "lighting device using the same, and display device." A phosphor film directly corresponds to a color coordinate conversion sheet/layer, and its use in a lighting device for a display is exactly the subject matter of US8408778. This patent was also cited in the IPR petition against US8408778.
    • Potential Anticipation: This is a highly relevant prior art. It very likely anticipates the concept of using a phosphor film (conversion sheet/layer) to convert light for a lighting device and display. The specific placement of this film (e.g., on top of optical sheets or integrated within them) and its interaction with multi-rank LEDs would need to be compared in detail with claims 1, 20, and 23. Its disclosure of a phosphor film for color adjustment strongly suggests anticipation of the core innovative aspects of US8408778.

  13. WO2006131924A2

    • Full Citation: WO2006131924A2, "Illumination apparatus," Oree, Advanced Illumination Solutions Inc.
    • Publication/Filing Date: Priority Date: 2005-06-07, Publication Date: 2006-12-14.
    • Brief Description: Describes an illumination apparatus.
    • Potential Anticipation: Requires further examination for details on color conversion sheets and multi-rank LED handling in a backlight context.

  14. US20070057626A1

    • Full Citation: US20070057626A1, "Illumination device and display device provided with the same," Matoko Kurihara.
    • Publication/Filing Date: Priority Date: 2005-09-15, Publication Date: 2007-03-15.
    • Brief Description: This is another patent by Kurihara, disclosing an "illumination device and display device." Given the previous Kurihara patent (US20060268537A1), this likely also deals with phosphor-based color conversion.
    • Potential Anticipation: Highly relevant, similar to US20060268537A1. It is likely to anticipate aspects of the color conversion sheet/layer, its function, and integration into a display device, impacting claims 1, 20, and 23.

  15. JP2007109616A

    • Full Citation: JP2007109616A, "LIGHT EMITTING DEVICE, LIGHTING DEVICE, ELECTRO-OPTICAL DEVICE, AND ELECTRONIC DEVICE," Epson Imaging Devices Corp.
    • Publication/Filing Date: Priority Date: 2005-09-16, Publication Date: 2007-04-26.
    • Brief Description: Broadly covers light-emitting devices and display devices.
    • Potential Anticipation: Needs detailed analysis to assess the presence of specific color conversion elements as described in US8408778's claims.

  16. US20070147081A1 (Shin)

    • Full Citation: US20070147081A1, "Blacklight unit, liquid crystal display device having the same, and method for providing substantially white light for liquid crystal display device," Lg.Philips Lcd Co. Ltd.
    • Publication/Filing Date: Priority Date: 2005-12-26, Publication Date: 2007-06-28.
    • Brief Description: This patent describes a "backlight unit" and "liquid crystal display device" with a "method for providing substantially white light." The objective of providing white light suggests some form of color adjustment, possibly using phosphors or combining different colored LEDs. This patent was also cited in the IPR petition against US8408778.
    • Potential Anticipation: This is a highly relevant prior art. It explicitly deals with providing white light for LCDs, a common goal of color conversion. It is very likely to disclose a backlight unit structure with LGP, LEDs, and optical sheets. The specific disclosure of how "substantially white light" is achieved (e.g., using a conversion sheet on top of optical sheets to adjust color coordinates, especially for non-ideal LEDs) would be crucial for anticipating claims 1, 20, and 23.

  17. WO2007086657A1

    • Full Citation: WO2007086657A1, "Backlight unit and lcd having the same," Lg Innotek Co., Ltd.
    • Publication/Filing Date: Priority Date: 2006-01-24, Publication Date: 2007-08-02.
    • Brief Description: Describes a "backlight unit and LCD." This is the original assignee of US8408778, indicating related technology.
    • Potential Anticipation: Being from the same original assignee, this patent is likely to be very relevant. It could potentially anticipate general backlight unit structures. A detailed comparison would be needed to see if it specifically discloses the conversion sheet's placement (on optical sheet top) and function in converting light that has passed through both diffusion and prism sheets, or a coating on the diffusion sheet as in claim 23, especially in the context of improving LED yield.

  18. WO2007138724A1

    • Full Citation: WO2007138724A1, "Backlight device and display device using same," Sharp Kabushiki Kaisha.
    • Publication/Filing Date: Priority Date: 2006-05-30, Publication Date: 2007-12-06.
    • Brief Description: Describes a "backlight device and display device."
    • Potential Anticipation: Could be relevant for general backlight configurations. Further review is needed for specific color conversion sheet details.

  19. US20090251922A1

    • Full Citation: US20090251922A1, "Backlight device and display device using the same," Sharp Kabushiki Kaisha.
    • Publication/Filing Date: Priority Date: 2006-05-30, Publication Date: 2009-10-08.
    • Brief Description: Appears to be a later publication from the same priority date as WO2007138724A1 by Sharp, likely a US counterpart.
    • Potential Anticipation: Same considerations as WO2007138724A1.

  20. US20080158907A1

    • Full Citation: US20080158907A1, "Backlight module having light guide plate with fluorescent layer thereon," Fitipower Integrated Technology, Inc.
    • Publication/Filing Date: Priority Date: 2006-12-27, Publication Date: 2008-07-03.
    • Brief Description: This patent explicitly discloses a "Backlight module having light guide plate with fluorescent layer thereon." The "fluorescent layer" is directly analogous to the "color coordinate conversion sheet/layer" of US8408778. The placement "on the light guide plate" is also highly relevant.
    • Potential Anticipation: This is a highly relevant prior art. It directly anticipates the use of a fluorescent layer on a light guide plate within a backlight module. Depending on the specifics of its claims, this could anticipate elements of claims 1, 20, and 23, particularly regarding the presence and function of a color converting layer in a backlight unit, especially if it describes the interaction with optical sheets.

  21. US20080302977A1

    • Full Citation: US20080302977A1, "Light emitting module for producing a visible light by passive ultraviolet excitation," Acpa Energy Conversion Devices Co., Ltd.
    • Publication/Filing Date: Priority Date: 2007-06-06, Publication Date: 2008-12-11.
    • Brief Description: Describes a light-emitting module that produces visible light via passive UV excitation. This implies the use of phosphors that convert UV light to visible light.
    • Potential Anticipation: While it involves color conversion via phosphors, the specific excitation by UV LEDs might differ from the typically blue LEDs of US8408778 (though blue LEDs can also excite phosphors). The key for anticipation would be whether it teaches the specific arrangement with an LGP, optical sheets (diffusion + prism), and a conversion sheet for color correction of multi-rank LEDs as claimed.

Summary of Most Relevant Prior Art:

Based on the titles and general understanding, the most relevant prior art references that directly relate to color conversion using fluorescent/phosphor materials in backlight units for displays are:

  • JP2003222861A (Citizen Electronics Co Ltd): Explicitly mentions a "Phosphor chromaticity correction plate." This directly addresses the core color conversion aspect.
  • US20060268537A1 (Kurihara): Discloses a "Phosphor film, lighting device using the same, and display device." This is very strong prior art for the color conversion sheet concept.
  • US20070057626A1 (Kurihara): Another Kurihara patent related to illumination and display devices, likely continuing the theme of phosphor-based color conversion.
  • US20070147081A1 (Shin): Describes a "Backlight unit, liquid crystal display device... and method for providing substantially white light." Providing white light is a key function of the color conversion sheet in US8408778.
  • US20080158907A1 (Fitipower Integrated Technology, Inc): Directly states "Backlight module having light guide plate with fluorescent layer thereon." This explicitly teaches a fluorescent layer on the LGP, which is highly relevant to the conversion sheet's placement and function.

These patents are strong candidates for anticipating elements of US8408778's independent claims (1, 20, 23), particularly the use of a color conversion layer/sheet containing fluorescent/phosphor material to adjust the color output of LEDs in a backlight unit for a display device. A definitive determination of anticipation would require a detailed claim-by-claim analysis against the full disclosure of each of these prior art documents.

Generated 5/24/2026, 12:47:01 AM