Kabushiki Kaisha Toshiba

Samsung Electronics Co., Ltd.

Aoi Okada

Yumi Fukuda

Naotoshi Matsuda

Iwao Mitsuishi

Shinya Nunoue

Masahiro Kato

Keiko Albessard

Ryosuke Hiramatsu

Kunio Ishida

Yasushi Hattori

Toshiki Hikosaka

Takahiro Sato

Shigeya Kimura

Hironori Asai

A light-emitting device of an embodiment includes a light-emitting element emitting blue excitation light and a first phosphor excited by the blue excitation light and emitting fluorescence. A peak wavelength of the fluorescence is not shorter than 520 nm and shorter than 660 nm and the peak wavelength of the fluorescence shifting in the same direction when a peak wavelength of the blue excitation light shifts. The first phosphor is one of a yellow phosphor emitting yellow fluorescence, a green phosphor emitting green fluorescence, a yellow-green/yellow phosphor emitting yellow-green/yellow fluorescence and a red phosphor emitting red fluorescence.

Light-emitting device with phosphor excited by blue excitation light

According to one embodiment, the luminescent material shows a luminescence peak in a wavelength range of 570 to 670 nm when excited with light having an emission peak in a wavelength range of 250 to 520 nm. The luminescent material includes a host material having a crystal structure substantially same as the crystal structure of SrSiAlON. The host material is activated by Eu, and includes Sr and Ca to satisfy a relationship of 0.008&#x2266;M/(M+M)&#x2266;0.114, where Mis a number of moles of Ca and Mis a number of moles of Sr.

Luminescent material

According to one embodiment, the phosphor exhibits a luminescence peak in a wavelength ranging from 500 to 600 nm when excited with light having an emission peak in a wavelength ranging from 250 to 500 nm. The phosphor has a composition represented by (MCe)AlSiON(M represents Sr and a part of Sr may be substituted by at least one selected from Ba, Ca, and Mg; x, y, z, u, and w satisfy 0&#x3c;x&#x2266;1, 0.8&#x2266;y&#x2266;1.1, 2&#x2266;z&#x2266;3.5, 0&#x3c;u&#x2266;1, 1.8&#x2266;z&#x2212;u, and 13&#x2266;u+w&#x2266;15). The phosphor has a crystalline aspect ratio of 1.5 to 10.

Phosphor

A light emitting device includes a light emitting element that emits light having a wavelength of 250 nm to 500 nm and a fluorescent layer that is disposed on the light emitting element. The fluorescent layer includes a phosphor having a composition expressed by the equation, ((MEu)SiAlON), and an average particle diameter of 12 &#x3bc;m or more, wherein in the equation, M is an element that is selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al, rare-earth elements, and IVB group elements, and x1, y, z, u, and w satisfy each of the inequalities simultaneously, that is to say each of the following inequalities is satisfied by the choice of values of the identified paramaters within the noted ranges of 0&#x3c;x1&#x3c;1, &#x2212;0.1&#x3c;y&#x3c;0.3, &#x2212;3&#x3c;z&#x2266;1, &#x2212;3&#x3c;u&#x2212;w&#x2266;1.5, 2&#x3c;u, w&#x3c;21.

Light emitting device and manufacturing method thereof

A light emitting device according to one embodiment includes a board; a light emitting element mounted on the board, emitting light having a wavelength of 250 nm to 500 nm; a red fluorescent layer formed on the element, including a red phosphor expressed by equation (1), having a semicircular shape with a diameter r;(MEu)SiAlON&#x2003;&#x2003;(1) (In the equation (1), M is an element that is selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al (Aliminum), rare-earth elements, and IVB group elements), an intermediate layer formed on the red fluorescent layer, being made of transparent resin, having a semicircular shape with a diameter D; and a green fluorescent layer formed on the intermediate layer, including a green phosphor, having a semicircular shape. A relationship between the diameter r and the diameter D satisfies equation (2):2(&#x3bc;m)&#x2266;&#x2266;(+1000)(&#x3bc;m).&#x2003;&#x2003;(2)

Light emitting device

The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1):(MEC)MAlON&#x2003;&#x2003;(1).In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; Mis different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0&#x3c;x&#x3c;0.2, 0.55&#x3c;a&#x3c;0.80, 2.10&#x3c;b&#x3c;3.90, 0&#x3c;c&#x2266;0.25 and 4&#x3c;d&#x3c;5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.

Red light-emitting flourescent substance and light-emitting device employing the same

A white light emitting device according to an embodiment includes: a light emitting element having a peak wavelength in a wavelength range of 430 nm or more and 470 nm or less; a first fluorescent material emits light with a first peak wavelength of 525 nm or more and 560 nm or less; a second fluorescent material emits light with a second peak wavelength longer than the first peak wavelength; and a third fluorescent material emits light with a third peak wavelength of 620 nm or more and 750 nm or less, which is longer than the second peak wavelength. The first fluorescent material and the second fluorescent material has a composition of MSiON, and when the first peak wavelength is denoted by &#x3bb;1 (nm), whereas the second peak wavelength is denoted by &#x3bb;2 (nm), 1100&#x2266;&#x3bb;1+&#x3bb;2 and &#x3bb;2&#x2212;&#x3bb;1&#x2266;60 are satisfied.

White light emitting device containing three fluorescent materials having different peak wavelengths

The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1):(MEC)MAlON&#x2003;&#x2003;(1).In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; Mis different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0&#x3c;x&#x3c;0.2, 0.63&#x3c;a&#x3c;0.80, 2.1&#x3c;b&#x3c;2.63, 0&#x3c;c&#x2266;0.24 and 4&#x3c;d&#x3c;5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.

Red light-emitting fluorescent substance and light-emitting device employing the same

According to one embodiment, the luminescent material emits light having an luminescence peak within a wavelength range of 550 to 590 nm when excited with light having an emission peak in a wavelength range of 250 to 520 nm. The luminescent material has a composition represented by the following formula 1.(SrEu)SiAlON&#x2003;&#x2003;formula 1

A light emitting device according to one embodiment includes a board; plural first light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm; plural second light emitting elements mounted on the board to emit light having a wavelength of 250 nm to 500 nm; a first fluorescent layer formed on each of the first light emitting elements, the first fluorescent layer including a first phosphor; and a second fluorescent layer formed on each of the second light emitting elements, the second fluorescent layer including a second phosphor. The second phosphor is higher than the first phosphor in luminous efficiency at 50&#xb0; C., and is lower than the first phosphor in the luminous efficiency at 150&#xb0; C.

The embodiment provides a process for production of an oxynitride fluorescent substance. An compound containing In or Ga is adopted in the process as a material thereof. The red fluorescent substance produced by the process can be combined with a semiconductor light-emitting element, so as to be used in a light-emitting device or a light-emitting module.

Fluorescent substance, process for production of fluorescent substance, light-emitting device and light-emitting module

A light emitting device according to one embodiment includes: a board; plural first light emitting units each including a first light emitting element and a first fluorescent layer formed on the first light emitting element having a green phosphor; plural second light emitting units each including a second light emitting element and a second fluorescent layer formed on the second light emitting element having a red phosphor; the second fluorescent layers and the first fluorescent layers being separated in a non-contact manner with gas interposed there between; and plural third light emitting units each including a third light emitting element and a resin layer formed on the third light emitting element having neither a green phosphor nor the red phosphor, the third light emitting units being disposed between the first light emitting units and the second light emitting units.

The embodiment provides a process for production of a green light-emitting oxynitride fluorescent material having SrAlSiONcrystal structure, and also provides the fluorescent material produced by that process. An metal halide is adopted in the process as one of the starting material metal compounds. As the metal halide, a Ca or Na compound as well as a Sr compound can be preferably employed.

Fluorescent material and light-emitting device employing the same

The fluorescent substance according to the embodiment is generally represented by (MEC)SiAlON, and is a kind of the SrSiAlONphosphors. The substance is in the form of crystals having a mean grain size of 20 to 100 &#x3bc;m, and the aspect ratio thereof is in the range of 2 to 4. This substance emits luminescence having a peak in the wavelength range of 580 to 660 nm when excited by light of 250 to 500 nm. The embodiment also provides a light-emitting device comprising this substance in combination with a light-emitting element and a green light-emitting fluorescent substance.

Fluorescent substance and light-emitting device employing the same

A light emitting device according to one embodiment includes a light emitting element that emits light having a wavelength of 380 nm to 470 nm; a CASN first red phosphor that is disposed on the light emitting element; a sialon second red phosphor that is disposed on the light emitting element; and a sialon green phosphor that is disposed on the light emitting element.

Growing community of inventors

Tokyo, Japan

Aoi Okada