Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate

Kimmo Keränen (Corresponding author), Mikko Heikkinen, Marianne Hiltunen, Markku Lahti, Jukka-Tapani Mäkinen, Antti Sunnari, Jari Rekilä, Kari Rönkä

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

3 Citations (Scopus)

Abstract

The dominant technology for manufacturing backlight illumination structures is typically based on use of individually packaged Surface Mount Device (SMD) Light Emitting Diodes (LEDs). The optical power from sources is coupled to the light guide having a special structure to couple light out so that uniform illumination is achieved to the illuminated component, typically LCD display. In practice the structure contains several separate diffuser films, which results to a thick and costly structure. In addition, the light coupling from LED to the light guide is sensitive to alignment errors causing nonuniform and inefficient illumination. The developed alternative packaging structure for backlighting solutions is based on inorganic LED devices and multilayer polymer substrate. Polycarbonate substrate material was used, which is highly transparent at visual band allowing low absorption and has good lamination properties in hot lamination process allowing compact integrated structures. In the manufacturing process the individual polymer sheets with an individual thickness of 100 μm were printed with conductive patterns produced by screen printing using silver-based thick film pastes. The final integrated multilayer structure containing embedded LED devices was produced in a hot lamination process. Two types of LED devices were embedded within the laminated structure, namely blue LED, type C470RT290 and green LED, type C527RT290. The bottom area of the chip was 300 μm × 300 μm and the thickness 115 μm. The devices were manufactured by Cree. Test samples containing 3 × 3, 5 × 5 and 5 × 7 LED devices were designed, implemented and characterized. The final laminated structure thickness was typically 300 μm. The performed designs verified by test structure implementations and characterizations showed that the final thickness of the backlight illumination structure depends of the required uniformity of illumination and allowed LED device pitch and used diffuser efficiency. The main advantages of the implemented system compared to traditional light guiding system are easy optical coupling with high efficiency in an integrated and thin package. The developed technology seems to be suitable to produce backlight illumination structures for applications in which thin, lightweight, efficient and cost-efficient backlight illumination structure is essential, such as, hand-held devices. In addition, the developed technology seems to be possible to apply in several other applications, such as, information tables, signboards and displays.
Original languageEnglish
Title of host publication2010 3rd Electronic System-Integration Technology Conference (ESTC 2010)
Subtitle of host publicationBerlin, Germany, 13-16 Sept. 2010
Place of PublicationPiscataway, NJ, USA
PublisherIEEE Institute of Electrical and Electronic Engineers
Number of pages4
ISBN (Electronic)978-1-4244-8555-0, 978-1-4244-8554-3
ISBN (Print)978-1-4244-8553-6
DOIs
Publication statusPublished - 2010
MoE publication typeA4 Article in a conference publication

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light emitting diodes
illumination
polymers
laminates
diffusers
manufacturing
optical coupling
polycarbonates
packaging
printing
thick films
chips
alignment
silver
costs

Cite this

Keränen, K., Heikkinen, M., Hiltunen, M., Lahti, M., Mäkinen, J-T., Sunnari, A., ... Rönkä, K. (2010). Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate. In 2010 3rd Electronic System-Integration Technology Conference (ESTC 2010): Berlin, Germany, 13-16 Sept. 2010 Piscataway, NJ, USA: IEEE Institute of Electrical and Electronic Engineers . https://doi.org/10.1109/ESTC.2010.5642993
Keränen, Kimmo ; Heikkinen, Mikko ; Hiltunen, Marianne ; Lahti, Markku ; Mäkinen, Jukka-Tapani ; Sunnari, Antti ; Rekilä, Jari ; Rönkä, Kari. / Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate. 2010 3rd Electronic System-Integration Technology Conference (ESTC 2010): Berlin, Germany, 13-16 Sept. 2010. Piscataway, NJ, USA : IEEE Institute of Electrical and Electronic Engineers , 2010.
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author = "Kimmo Ker{\"a}nen and Mikko Heikkinen and Marianne Hiltunen and Markku Lahti and Jukka-Tapani M{\"a}kinen and Antti Sunnari and Jari Rekil{\"a} and Kari R{\"o}nk{\"a}",
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Keränen, K, Heikkinen, M, Hiltunen, M, Lahti, M, Mäkinen, J-T, Sunnari, A, Rekilä, J & Rönkä, K 2010, Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate. in 2010 3rd Electronic System-Integration Technology Conference (ESTC 2010): Berlin, Germany, 13-16 Sept. 2010. IEEE Institute of Electrical and Electronic Engineers , Piscataway, NJ, USA. https://doi.org/10.1109/ESTC.2010.5642993

Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate. / Keränen, Kimmo (Corresponding author); Heikkinen, Mikko; Hiltunen, Marianne; Lahti, Markku; Mäkinen, Jukka-Tapani; Sunnari, Antti; Rekilä, Jari; Rönkä, Kari.

2010 3rd Electronic System-Integration Technology Conference (ESTC 2010): Berlin, Germany, 13-16 Sept. 2010. Piscataway, NJ, USA : IEEE Institute of Electrical and Electronic Engineers , 2010.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate

AU - Keränen, Kimmo

AU - Heikkinen, Mikko

AU - Hiltunen, Marianne

AU - Lahti, Markku

AU - Mäkinen, Jukka-Tapani

AU - Sunnari, Antti

AU - Rekilä, Jari

AU - Rönkä, Kari

PY - 2010

Y1 - 2010

N2 - The dominant technology for manufacturing backlight illumination structures is typically based on use of individually packaged Surface Mount Device (SMD) Light Emitting Diodes (LEDs). The optical power from sources is coupled to the light guide having a special structure to couple light out so that uniform illumination is achieved to the illuminated component, typically LCD display. In practice the structure contains several separate diffuser films, which results to a thick and costly structure. In addition, the light coupling from LED to the light guide is sensitive to alignment errors causing nonuniform and inefficient illumination. The developed alternative packaging structure for backlighting solutions is based on inorganic LED devices and multilayer polymer substrate. Polycarbonate substrate material was used, which is highly transparent at visual band allowing low absorption and has good lamination properties in hot lamination process allowing compact integrated structures. In the manufacturing process the individual polymer sheets with an individual thickness of 100 μm were printed with conductive patterns produced by screen printing using silver-based thick film pastes. The final integrated multilayer structure containing embedded LED devices was produced in a hot lamination process. Two types of LED devices were embedded within the laminated structure, namely blue LED, type C470RT290 and green LED, type C527RT290. The bottom area of the chip was 300 μm × 300 μm and the thickness 115 μm. The devices were manufactured by Cree. Test samples containing 3 × 3, 5 × 5 and 5 × 7 LED devices were designed, implemented and characterized. The final laminated structure thickness was typically 300 μm. The performed designs verified by test structure implementations and characterizations showed that the final thickness of the backlight illumination structure depends of the required uniformity of illumination and allowed LED device pitch and used diffuser efficiency. The main advantages of the implemented system compared to traditional light guiding system are easy optical coupling with high efficiency in an integrated and thin package. The developed technology seems to be suitable to produce backlight illumination structures for applications in which thin, lightweight, efficient and cost-efficient backlight illumination structure is essential, such as, hand-held devices. In addition, the developed technology seems to be possible to apply in several other applications, such as, information tables, signboards and displays.

AB - The dominant technology for manufacturing backlight illumination structures is typically based on use of individually packaged Surface Mount Device (SMD) Light Emitting Diodes (LEDs). The optical power from sources is coupled to the light guide having a special structure to couple light out so that uniform illumination is achieved to the illuminated component, typically LCD display. In practice the structure contains several separate diffuser films, which results to a thick and costly structure. In addition, the light coupling from LED to the light guide is sensitive to alignment errors causing nonuniform and inefficient illumination. The developed alternative packaging structure for backlighting solutions is based on inorganic LED devices and multilayer polymer substrate. Polycarbonate substrate material was used, which is highly transparent at visual band allowing low absorption and has good lamination properties in hot lamination process allowing compact integrated structures. In the manufacturing process the individual polymer sheets with an individual thickness of 100 μm were printed with conductive patterns produced by screen printing using silver-based thick film pastes. The final integrated multilayer structure containing embedded LED devices was produced in a hot lamination process. Two types of LED devices were embedded within the laminated structure, namely blue LED, type C470RT290 and green LED, type C527RT290. The bottom area of the chip was 300 μm × 300 μm and the thickness 115 μm. The devices were manufactured by Cree. Test samples containing 3 × 3, 5 × 5 and 5 × 7 LED devices were designed, implemented and characterized. The final laminated structure thickness was typically 300 μm. The performed designs verified by test structure implementations and characterizations showed that the final thickness of the backlight illumination structure depends of the required uniformity of illumination and allowed LED device pitch and used diffuser efficiency. The main advantages of the implemented system compared to traditional light guiding system are easy optical coupling with high efficiency in an integrated and thin package. The developed technology seems to be suitable to produce backlight illumination structures for applications in which thin, lightweight, efficient and cost-efficient backlight illumination structure is essential, such as, hand-held devices. In addition, the developed technology seems to be possible to apply in several other applications, such as, information tables, signboards and displays.

U2 - 10.1109/ESTC.2010.5642993

DO - 10.1109/ESTC.2010.5642993

M3 - Conference article in proceedings

SN - 978-1-4244-8553-6

BT - 2010 3rd Electronic System-Integration Technology Conference (ESTC 2010)

PB - IEEE Institute of Electrical and Electronic Engineers

CY - Piscataway, NJ, USA

ER -

Keränen K, Heikkinen M, Hiltunen M, Lahti M, Mäkinen J-T, Sunnari A et al. Backlight illumination structure based on inorganic LED devices and laminated multilayer polymer substrate. In 2010 3rd Electronic System-Integration Technology Conference (ESTC 2010): Berlin, Germany, 13-16 Sept. 2010. Piscataway, NJ, USA: IEEE Institute of Electrical and Electronic Engineers . 2010 https://doi.org/10.1109/ESTC.2010.5642993