Kabushiki Kaisha Toshiba

Misawa Co. Ltd.

Alpad Corporation

Iwao Mitsuishi

Shinya Nunoue

Naotoshi Matsuda

Yumi Fukuda

Aoi Okada

Keiko Albessard

Masahiro Kato

Yasushi Hattori

Takahiro Sato

Ryosuke Hiramatsu

Toshiki Hikosaka

Shinji Saito

Kunio Ishida

Kuniaki Konno

Hiroshi Kukimoto

Shigeya Kimura

Naomi Shida

Hiroshi Endo

Koichi Tachibana

Genichi Hatakoshi

Masaaki Tamatani

Takashi Yasuda

Atsuko Iida

Miwa Okumura

Fumio Ueno

Hironori Asai

Motomasa Imai

Naoki Shutoh

Hideyasu Andoh

Fusayoshi Kido

Shoji Kozuka

Sinya Nunoue

Aoi Okoda

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

A light emitting device according to embodiments includes a light emitting element emitting light having a peak wavelength of 425 nm or more and 465 nm or less, a first phosphor emitting light having a peak wavelength of 485 nm or more and 530 nm or less, a second phosphor emitting light having a peak wavelength longer than that of the first phosphor, and a third phosphor emitting light having a peak wavelength longer than that of the second phosphor. Then, when the peak wavelength of the light emitting element is &#x3bb;(nm) and the peak wavelength of the first phosphor is &#x3bb;(nm), a relation of 30&#x2266;&#x3bb;&#x2212;&#x3bb;&#x2266;70 is satisfied.

Light emitting device

The present embodiments provide a europium-activated oxynitride phosphor and a production method thereof. This phosphor emits red luminescence having a peak at 630 nm or longer and can be produced by use of inexpensive oxides as raw materials containing alkaline earth metals such as strontium. The oxynitride phosphor is activated by a divalent europium and represented by the formula (1):(MEu)AlSiONC&#x2003;&#x2003;(1). In the formula, M is an alkaline earth metal, and x, a, b, c, d and e are numbers satisfying the conditions of 0&#x3c;x&#x3c;0.2, 1.3&#x2266;a&#x2266;1.8, 3.5&#x2266;b&#x2266;4, 0.1&#x2266;c&#x2266;0.3, 6.7&#x2266;d&#x2266;7.2 and 0.01&#x2266;e&#x2266;0.1, respectively.

Phosphors and method for producing thereof

According to one embodiment, the luminescent material 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 luminescent material has a composition represented by Formula 1 below:(MCe)AlSiON&#x2003;&#x2003;Formula 1wherein 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 following conditions:

Luminescent material

Disclosed is a white light emitting device including a semiconductor light emitting element configured to emit near ultraviolet light having a peak wavelength ranging from 380 to 410 nm, a first phosphor layer and a second phosphor layer. The first phosphor layer contains a blue-emitting phosphor configured to emit blue light by the near ultraviolet light, and a red-emitting phosphor activated by trivalent europium and configured to emit red light by the near ultraviolet light. The second phosphor layer contains a green-emitting phosphor configured to emit green light by the near ultraviolet light. The semiconductor light emitting element, the first phosphor layer and the second phosphor layer are laminated in this order to emit white 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.

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)

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

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, a light emitting device includes a semiconductor light emitting element, a mounting member, a first wavelength conversion layer, and a first transparent layer. The semiconductor light emitting element emits a first light. The semiconductor light emitting element is placed on the mounting member. The first wavelength conversion layer is provided between the semiconductor light emitting element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The first transparent layer is provided between the semiconductor light emitting element and the first wavelength conversion layer in contact with the semiconductor light emitting element and the first wavelength conversion layer. The first transparent layer is transparent to the first light and the second light.

According to one embodiment, a light emitting device includes a semiconductor light emitting element to emit a first light, a mounting member, first and second wavelength conversion layers and a transparent layer. The first wavelength conversion layer is provided between the element and the mounting member in contact with the mounting member. The first wavelength conversion layer absorbs the first light and emits a second light having a wavelength longer than a wavelength of the first light. The semiconductor light emitting element is disposed between the second wavelength conversion layer and the first wavelength conversion layer. The second wavelength conversion layer absorbs the first light and emits a third light having a wavelength longer than the wavelength of the first light. The transparent layer is provided between the element and the second wavelength conversion layer. The transparent layer is transparent to the first, second, and third lights.

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.

Growing community of inventors

Tokyo, Japan

Iwao Mitsuishi