EP2175436A1 - Punktmatrix- und segmentierte Anzeigen mit gleichmäßiger Beleuchtung - Google Patents

Punktmatrix- und segmentierte Anzeigen mit gleichmäßiger Beleuchtung Download PDF

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Publication number
EP2175436A1
EP2175436A1 EP08017601A EP08017601A EP2175436A1 EP 2175436 A1 EP2175436 A1 EP 2175436A1 EP 08017601 A EP08017601 A EP 08017601A EP 08017601 A EP08017601 A EP 08017601A EP 2175436 A1 EP2175436 A1 EP 2175436A1
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EP
European Patent Office
Prior art keywords
display
light
phosphor
phosphors
led
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08017601A
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English (en)
French (fr)
Inventor
Richard Peter James Barton
William Wallace May
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Individual
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Individual
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Publication date
Application filed by Individual filed Critical Individual
Priority to EP08017601A priority Critical patent/EP2175436A1/de
Publication of EP2175436A1 publication Critical patent/EP2175436A1/de
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/302—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements characterised by the form or geometrical disposition of the individual elements
    • G09F9/3023—Segmented electronic displays

Definitions

  • This invention relates to displays, and in particular to white and coloured dot-matrix and segmented displays in which the colour is produced by means of blue or ultra-violet light-emitting diodes (LED) together with a wavelength conversion phosphor, or combination of phosphors.
  • LED ultra-violet light-emitting diodes
  • a typical manufacturing process for a dot-matrix or segmented display corresponding to the existing art is described here with reference to Figure 2 .
  • a single moulding 11 is produced with holes 12 at the position of each illuminable element in the display. Around each of these holes the moulding forms a reflector cup which serves to prevent light from leaking from one hole to adjacent holes.
  • the surface of the moulding 11 is made opaque either by including suitable light absorbing substance in the material of the moulding or by coating the surface of the moulding with an opaque paint.
  • LED chips 8 are mounted on a printed circuit board 9 carrying two sets of addressing contact lines, usually one on the top surface, and the second set on the lower surface. Where necessary, standard plated-through via holes allow electrical contact to be made between the lower addressing lines and the LEDs.
  • the circuit board is placed in position using locating pegs so that one or more LEDs is contained inside each reflector cup, and the complete assembly is then filled with a clear epoxy 10 which may contain a diffusing material such as titania (titanium dioxide) particles.
  • a clear epoxy 10 which may contain a diffusing material such as titania (titanium dioxide) particles.
  • titania titanium dioxide
  • the epoxy may alternatively or additionally contain phosphor particles 13 which can be excited by the blue or UV LED array 8.
  • the epoxy serves to maintain the whole assembly rigidly together, to protect the printed circuit board, to improve light extraction from the LED chip, and to maintain in position the pins used for electrical connection between the LED chips and the addressing lines.
  • the solution described in the patent is to mount the LEDs on a single board, with electrodes on the upper and lower faces, and define the display pattern by means of holes in a flexible sheet that is bonded to the board by means of epoxy only at the position of the LEDs. It is claimed that flexibility of the sheet prevents distortion.
  • a subsequent patent US 4914731 describes another simplified method of fabricating LED dot-matrix and segment displays.
  • the display is formed from three injection moulded elements together with a circuit board on which the LEDs are mounted.
  • the first injection moulded element is a lens, circular for a dot-matrix display or lozenge shaped for a segment display, the second is a screen which has holes defining the display pattern, and the third is the reflector cup to contain the LED and which has a reflecting coating on the inside.
  • the three injection moulded elements are pushed together, and the circuit board glued to the back to form the complete display. It is claimed that this method reduces manufacturing costs, and eliminates the need to cover the inside of the cups holding the LEDs or the edges of the display with an opaque ink to prevent leakage of light.
  • European Patent Application EP1566848 filed by Lumileds Lighting (and based on a US Patent Application 20050184638 ) describes an extension of earlier LED patents concerning more than one phosphor incorporated into an LED in order to improve the quality of the white light.
  • the invention is intended to overcome the stated problem of interaction between phosphors by including them in discrete layers or over separate areas.
  • Dichroic filters are also included to transmit and reflect specified wavelengths in the illumination devices.
  • the implied applications include illumination of a Liquid Crystal Display (LCD) but all the claims are concerned exclusively with ways in which different phosphors can be combined. No claims are included in the patent for dot matrix or segment displays.
  • European patent application publication number EP1667091 describes an LED display showing digital characters or patterns.
  • Patent application EP1667091 claims that the use of a shaped cavity and "an optically conductive ink" can give internal reflection effects which lead to a more uniform display pattern.
  • the cavity containing the LEDs is narrower at the top than at the base and a screen diffuser is used in place of the diffusing epoxy. No phosphor is described in this patent.
  • US2005006659 refers only to LEDs for lighting and the invention is intended as a candidate for replacement of incandescent and fluorescent lights, and not for use in a display. Together with the use of the cap to cover only a single LED, and no mention of displays in the application, it is clear that US2005006659 is referring to a completely different application of a LED-phosphor combination.
  • the phosphor-containing cap is taken to be a preformed three-dimensional discrete entity, either a single crystal or prepared by "transfer moulding, injection moulding or casting".
  • the specific embodiment of the phosphor layer described in this application is prepared by the essentially two-dimensional techniques of screen printing or similar method of thin film deposition.
  • a problem with previous dot-matrix and segmented displays and one not addressed in previous patents concerned with phosphor conversion displays is lack of uniformity of the illuminated area in the display. Segregation and agglomeration of the phosphor in the epoxy gives a non-uniform phosphor distribution that in turn gives a non-uniform appearance to the display and can allow the underlying LEDs to be observed as bright spots within the illuminated areas of the display.
  • the invention described in the present patent uses a film or layer of phosphor or phosphor containing material to provide a uniform and consistent coating that produces uniform illumination.
  • the invention described in the present patent is a method of manufacture of white and other phosphor-conversion LED dot-matrix or segment displays that also avoids the degradation observed in earlier displays, and gives more uniform colour in the case of phopshor converted displays.
  • the display is realised in the conventional way except for the way in which the phosphor material is incorporated.
  • the blue or UV LED chips 1 are attached to the printed circuit board 2 for example by soldering or epoxy die attach, and the display pattern is defined by moulding 3 .
  • the display can be any segmented or dot matrix display or any other displays that require illuminated and dark regions.
  • Other ways of holding the LED lamps in position can also be used and different phosphors can be used to produce light with different chromaticity co-ordinates. Examples include in particular the use of phosphors that emit green light in order to overcome the well-known problem of low efficiency for LEDs emitting in the green region of the spectrum.
  • Other methods of depositing the phosphors on the substrate can also be used in addition to those described above, and a range of materials can be used as the substrate.
  • a major advantage of the method described in step 4) is the ability to control the thickness of the phosphor, and hence to control the quality and consistency of the light emitted from the display.
  • the earlier approach where the phosphor was incorporated in the epoxy 10 in Figure 2 gives rise to problems of settlement and aggregation that makes it difficult to control the amount of phosphor emission and to control the uniformity of the emission in different directions.
  • the thickness of the phosphor layer will depend on the phosphor being used, but is typically in the range 5 to 100 microns. More than one layer can be applied successively in order to improve the uniformity and to control the thickness.
  • the distribution of particle sizes in the phosphor is not critical, but for effective screen printing the maximum diameter of the phosphor particles should typically be below 20 microns.
  • Phosphor particles can both scatter the blue light, where the direction of propagation is changed but the wavelength is unchanged, and convert blue light to light of a longer wavelength.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Led Device Packages (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
EP08017601A 2008-10-08 2008-10-08 Punktmatrix- und segmentierte Anzeigen mit gleichmäßiger Beleuchtung Withdrawn EP2175436A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08017601A EP2175436A1 (de) 2008-10-08 2008-10-08 Punktmatrix- und segmentierte Anzeigen mit gleichmäßiger Beleuchtung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP08017601A EP2175436A1 (de) 2008-10-08 2008-10-08 Punktmatrix- und segmentierte Anzeigen mit gleichmäßiger Beleuchtung

Publications (1)

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EP2175436A1 true EP2175436A1 (de) 2010-04-14

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012006548A1 (de) * 2012-04-02 2013-10-02 MENTOR GmbH & Co Präzisions-Bauteile KG Anzeigeeinrichtung
JP2014137582A (ja) * 2013-01-18 2014-07-28 Sony Corp 表示パネルおよび表示装置
EP2884317A1 (de) * 2013-12-16 2015-06-17 Ict Ag Verfahren und Vorrichtung zur Verringerung des Moiré Effektes bei TV-Aufnahmen von LED-Bildwänden
US9313858B2 (en) 2011-06-10 2016-04-12 Koninklijke Philips N.V. Phosphor enhanced light source for presenting a visible pattern and a luminaire
WO2018005232A1 (en) * 2016-06-29 2018-01-04 Sharp Kabushiki Kaisha Laminated printed color conversion phosphor sheets
CN108281092A (zh) * 2018-01-24 2018-07-13 福州大学 一种微米级led显示光效提取的微结构及其制造方法
DE102017209071A1 (de) * 2017-05-30 2018-12-06 BSH Hausgeräte GmbH Streifenleuchte
WO2020187366A3 (de) * 2019-03-15 2020-12-30 OSRAM CONTINENTAL GmbH Optische vorrichtung, anordnung, fahrzeugleuchte und verfahren
FR3097936A1 (fr) * 2019-06-28 2021-01-01 Valeo Vision Dispositif lumineux pour véhicule automobile
CN113437054A (zh) * 2014-06-18 2021-09-24 艾克斯展示公司技术有限公司 微组装led显示器

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713579A (en) 1984-11-12 1987-12-15 Takiron Co., Ltd. Dot matrix luminous display
US4914731A (en) 1987-08-12 1990-04-03 Chen Shen Yuan Quickly formed light emitting diode display and a method for forming the same
US6165631A (en) 1997-03-04 2000-12-26 U.S. Philips Corporation Diode-addressed color display with lanthanoid phosphors
US20050006659A1 (en) 2003-07-09 2005-01-13 Ng Kee Yean Light emitting diode utilizing a discrete wavelength-converting layer for color conversion
US20050174770A1 (en) * 2004-02-05 2005-08-11 Marpole International, Inc. Light display structures
EP1566848A2 (de) 2004-02-23 2005-08-24 LumiLeds Lighting U.S., LLC Leuchtdiode mit Wellenlängen-Konversion
US20060111981A1 (en) * 1999-04-28 2006-05-25 Hunter Charles E Methods and apparatus for ultra-violet stimulated displays
EP1667091A2 (de) 2004-12-06 2006-06-07 Wai Ho LED-Anzeigevorrichtung
US20080060236A1 (en) 2006-09-08 2008-03-13 John Chiang Simulated neon illuminating sign
US20080116468A1 (en) * 2006-11-22 2008-05-22 Gelcore Llc LED backlight using discrete RGB phosphors
WO2008082136A1 (en) * 2006-12-28 2008-07-10 Seoul Semiconductor Co., Ltd. Back lighting unit having phosphor film structure

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713579A (en) 1984-11-12 1987-12-15 Takiron Co., Ltd. Dot matrix luminous display
US4914731A (en) 1987-08-12 1990-04-03 Chen Shen Yuan Quickly formed light emitting diode display and a method for forming the same
US6165631A (en) 1997-03-04 2000-12-26 U.S. Philips Corporation Diode-addressed color display with lanthanoid phosphors
US20060111981A1 (en) * 1999-04-28 2006-05-25 Hunter Charles E Methods and apparatus for ultra-violet stimulated displays
US20050006659A1 (en) 2003-07-09 2005-01-13 Ng Kee Yean Light emitting diode utilizing a discrete wavelength-converting layer for color conversion
US20050174770A1 (en) * 2004-02-05 2005-08-11 Marpole International, Inc. Light display structures
EP1566848A2 (de) 2004-02-23 2005-08-24 LumiLeds Lighting U.S., LLC Leuchtdiode mit Wellenlängen-Konversion
US20050184638A1 (en) 2004-02-23 2005-08-25 Lumileds Lighting, U.S., Llc Wavelength converted semiconductor light emitting devices
EP1667091A2 (de) 2004-12-06 2006-06-07 Wai Ho LED-Anzeigevorrichtung
US20080060236A1 (en) 2006-09-08 2008-03-13 John Chiang Simulated neon illuminating sign
US20080116468A1 (en) * 2006-11-22 2008-05-22 Gelcore Llc LED backlight using discrete RGB phosphors
WO2008082136A1 (en) * 2006-12-28 2008-07-10 Seoul Semiconductor Co., Ltd. Back lighting unit having phosphor film structure

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9313858B2 (en) 2011-06-10 2016-04-12 Koninklijke Philips N.V. Phosphor enhanced light source for presenting a visible pattern and a luminaire
RU2617672C2 (ru) * 2011-06-10 2017-04-26 Филипс Лайтинг Холдинг Б.В. Усиленный люминофором источник света для представления видимого рисунка и осветительное устройство
DE102012006548A1 (de) * 2012-04-02 2013-10-02 MENTOR GmbH & Co Präzisions-Bauteile KG Anzeigeeinrichtung
JP2014137582A (ja) * 2013-01-18 2014-07-28 Sony Corp 表示パネルおよび表示装置
EP2884317A1 (de) * 2013-12-16 2015-06-17 Ict Ag Verfahren und Vorrichtung zur Verringerung des Moiré Effektes bei TV-Aufnahmen von LED-Bildwänden
CN113437054A (zh) * 2014-06-18 2021-09-24 艾克斯展示公司技术有限公司 微组装led显示器
WO2018005232A1 (en) * 2016-06-29 2018-01-04 Sharp Kabushiki Kaisha Laminated printed color conversion phosphor sheets
US10262978B2 (en) * 2016-06-29 2019-04-16 eLux, Inc. Method for fabricating an emissive display using laminated printed color conversion phosphor sheets
DE102017209071A1 (de) * 2017-05-30 2018-12-06 BSH Hausgeräte GmbH Streifenleuchte
CN108281092A (zh) * 2018-01-24 2018-07-13 福州大学 一种微米级led显示光效提取的微结构及其制造方法
WO2020187366A3 (de) * 2019-03-15 2020-12-30 OSRAM CONTINENTAL GmbH Optische vorrichtung, anordnung, fahrzeugleuchte und verfahren
CN113632001A (zh) * 2019-03-15 2021-11-09 欧司朗大陆有限责任公司 光学装置，布置，车灯和方法
US20220186911A1 (en) * 2019-03-15 2022-06-16 OSRAM CONTINENTAL GmbH Optical Device, Arrangement, Vehicle Lamp and Method
FR3097936A1 (fr) * 2019-06-28 2021-01-01 Valeo Vision Dispositif lumineux pour véhicule automobile

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