JPH092866A - Ferrite with minor electric power loss for liquid crystal backlight - Google Patents
Ferrite with minor electric power loss for liquid crystal backlightInfo
- Publication number
- JPH092866A JPH092866A JP7157334A JP15733495A JPH092866A JP H092866 A JPH092866 A JP H092866A JP 7157334 A JP7157334 A JP 7157334A JP 15733495 A JP15733495 A JP 15733495A JP H092866 A JPH092866 A JP H092866A
- Authority
- JP
- Japan
- Prior art keywords
- power loss
- liquid crystal
- electric power
- ferrite
- crystal backlight
- 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.)
- Granted
Links
Landscapes
- Liquid Crystal (AREA)
- Magnetic Ceramics (AREA)
- Soft Magnetic Materials (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、液晶バックライト用イ
ンバータートランス磁心等に好適な低損失フェライトに
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low loss ferrite suitable for an inverter transformer magnetic core for a liquid crystal backlight.
【０００２】[0002]
【従来の技術】各種通信機器、民生用機器等のトランス
用材料として、Ｍｎ―Ｚｎ系フェライトが使用されてい
る。このトランス用材料としては、低損失であることが
求められている。従来の低損失フェライトとしては、種
々の組成のものが既に提案されている。例えば、特開平
３―２４８４０５号には、Ｆｅ2Ｏ3、ＭｎＯ、ＺｎＯを
主成分とし、副成分として、ＣａＯ ２００〜１０００
ｐｐｍ、ＳｉＯ2 ５００ｐｐｍ以下（０を含まず）、
Ｎｂ2Ｏ5 １５００ｐｐｍ以下（０を含まず）、Ｔａ2
Ｏ5１５００ｐｐｍ以下（０を含まず）を複合添加した
電源用低損失フェライトが開示されている。この低損失
フェライトでは、１００ｋＨｚ、２００ｍＴで電力損失
が３００程度の材料が得られている。2. Description of the Related Art Mn--Zn ferrite is used as a transformer material for various communication devices, consumer devices and the like. This transformer material is required to have low loss. Conventional low-loss ferrites having various compositions have already been proposed. For example, in JP-A-3-248405, Fe 2 O 3 , MnO, and ZnO are used as main components, and CaO 200 to 1000 as auxiliary components.
ppm, SiO 2 500 ppm or less (not including 0),
Nb 2 O 5 1500ppm or less (not including 0), Ta 2
O 5 1500 ppm or less (not including 0) complex added power low loss ferrite is disclosed. With this low-loss ferrite, a material having a power loss of about 300 at 100 kHz and 200 mT has been obtained.
【０００３】[0003]
【発明が解決しようとする課題】スイッチング電源用ト
ランスの動作温度は、７０℃前後であり、上記従来材の
電力損失が最小となる温度は、トランスの発熱防止のた
め、１００℃前後に設計されている。しかしながら、近
年では、例えば液晶バックライト用トランスに使用され
る用途では、動作温度が室温付近と低いため、その電力
損失が最小となる温度、所謂ボトム温度を６０℃以下に
する要求がある。本発明は、上記のことを鑑みて、電力
損失のボトム温度が２０〜６０℃であり、低損失な液晶
バックライト用低損失フェライトを提供することを目的
とする。The operating temperature of the switching power supply transformer is around 70 ° C., and the temperature at which the power loss of the conventional material is minimum is designed around 100 ° C. to prevent heat generation of the transformer. ing. However, in recent years, for example, in applications used for liquid crystal backlight transformers, since the operating temperature is as low as room temperature, there is a demand for the temperature at which the power loss is minimized, the so-called bottom temperature, to be 60 ° C. or less. In view of the above, it is an object of the present invention to provide a low loss ferrite for a liquid crystal backlight, which has a bottom temperature of power loss of 20 to 60 ° C.
【０００４】[0004]
【課題を解決するための手段】本発明は、Ｆｅ2Ｏ3 ５
３．０〜５４．５モル％、ＺｎＯ ６〜１２モル％、残
部ＭｎＯからなる主成分と、副成分として、ＣａＯ ２
００〜１０００ｐｐｍ、ＳｉＯ2 ０〜３００ｐｐｍ
（但し０ｐｐｍを含まない）、ＣｏＯ １００〜４００
０ｐｐｍ含有し、更にＮｂ2Ｏ5、Ｔａ2Ｏ5の少なくとも
１種を５０〜５００ｐｐｍ含有し、１００ｋＨｚ、２０
０ｍＴでの電力損失が４００ｋＷ／ｍ3以下で、その電
力損失の最小値を得る温度が２０〜６０℃であることを
特徴とする液晶バックライト用低損失フェライトであ
る。また本発明は、その液晶バックライト用低損失フェ
ライトにおいて、平均結晶粒径が５〜１５μｍであるこ
とを特徴とするものである。SUMMARY OF THE INVENTION The present invention relates to Fe 2 O 3 5
A main component consisting of 3.0 to 54.5 mol%, ZnO 6 to 12 mol% and the balance MnO, and CaO 2 as a subcomponent.
00~1000ppm, SiO 2 0~300ppm
(However, 0 ppm is not included), CoO 100-400
0 ppm, and further contains 50 to 500 ppm of at least one of Nb 2 O 5 and Ta 2 O 5 , 100 kHz, 20
A low-loss ferrite for a liquid crystal backlight, which has a power loss at 0 mT of 400 kW / m 3 or less and a temperature at which the minimum value of the power loss is obtained is 20 to 60 ° C. Further, the present invention is characterized in that the low-loss ferrite for a liquid crystal backlight has an average crystal grain size of 5 to 15 μm.
【０００５】[0005]
【作用】本発明において、各範囲を規定した理由は、以
下のとおりである。主成分は、Ｆｅ2Ｏ3が５３．０モル
％未満、またはＺｎＯが６モル％未満であると、電力損
失の最小値を得る温度が６０℃以上となり、これに伴い
２０〜６０℃における電力損失が増大し、４００ｋＷ／
ｍ3を越える。また、Ｆｅ2Ｏ3が５４．５モル％を超
過、またはＺｎＯが１２モル％を超過すると、電力損失
の最小値を得る温度が２０℃以下となり、これに伴い２
０〜６０℃における電力損失が増大し、４００ｋＷ／ｍ
3を越える。副成分は、ＣａＯ、ＳｉＯ2の添加量が範囲
に満たないと、２０〜６０℃における損失が４００ｋＷ
／ｍ3を越え、またＣａＯが範囲を越えると粒界応力の
増加に伴い、電力損失が増大し、ＳｉＯ2が範囲を越え
ると、異常粒成長が発生して、損失が増大するためであ
る。ＣｏＯは、添加量が１００ｐｐｍ未満では、電力損
失の低減効果が少なく、環境温度の変動に対する電力損
失の変化が大きくなる。一方、添加量が４０００ｐｐｍ
を超過すると、電力損失の温度変化は少ないが、電力損
失の最小値を得る温度が大幅に低下し、２０℃以下とな
る。Ｎｂ2Ｏ5、Ｔａ2Ｏ5は、範囲に満たない場合では電
力損失の低減効果が少なく、範囲を越えると異常粒成長
が発生して、電力損失が増大する。また、このＮｂ
2Ｏ5、Ｔａ2Ｏ5は、総量で、５００ｐｐｍ以下であるこ
とが望ましい。また、平均結晶粒径は、５〜１５μｍが
適当であり、好ましくは、６〜１２μｍである。In the present invention, the reason for defining each range is as follows. When Fe 2 O 3 is less than 53.0 mol% or ZnO is less than 6 mol% as the main component, the temperature at which the minimum value of power loss is obtained is 60 ° C. or higher, and accordingly, the power at 20 to 60 ° C. Loss increases, 400kW /
exceeds m 3 . Further, when Fe 2 O 3 exceeds 54.5 mol% or ZnO exceeds 12 mol%, the temperature at which the minimum value of the power loss is obtained becomes 20 ° C. or less, and accordingly, 2
Increased power loss at 0-60 ° C, 400kW / m
Over 3 . If the additive amount of CaO and SiO 2 is less than the range, the loss of 400kW at 20-60 ℃
/ M 3 and when CaO exceeds the range, power loss increases with an increase in grain boundary stress, and when SiO 2 exceeds the range, abnormal grain growth occurs and the loss increases. . When the amount of CoO added is less than 100 ppm, the effect of reducing power loss is small, and the change in power loss with respect to environmental temperature changes becomes large. On the other hand, the added amount is 4000ppm
When the temperature exceeds, the temperature change of the power loss is small, but the temperature at which the minimum value of the power loss is obtained is significantly lowered to 20 ° C. or less. Nb 2 O 5 and Ta 2 O 5 are less effective in reducing the power loss when they are less than the range, and when they exceed the range, abnormal grain growth occurs and the power loss increases. Also, this Nb
The total amount of 2 O 5 and Ta 2 O 5 is preferably 500 ppm or less. The average crystal grain size is suitably 5 to 15 μm, preferably 6 to 12 μm.
【０００６】[0006]
【実施例】以下に本発明に関する液晶バックライト用低
損失フェライトの実施例を説明する。まず、Ｆｅ2Ｏ3、
ＭｎＯ、ＺｎＯを所定量秤量し、９００℃で仮焼し、副
成分としてＣａＯ（ＣａＣＯ3で添加）、ＳｉＯ2、Ｃｏ
Ｏ、Ｎｂ2Ｏ5、Ｔａ2Ｏ5を所定量添加し、ボールミルで
１２時間粉砕し、バインダーを１ｗｔ％添加してスプレ
ー造粒した。これを成形し、保持温度１３００℃で５時
間焼成し、外径２５ｍｍ、内径１５ｍｍ、高さ５ｍｍの
リング形コア（試料）を製造した。この各試料の成分を
表１に示す。又、各試料の電力損失の最小値とそのとき
の温度（ボトム温度）、初透磁率、焼結密度及び平均結
晶粒径を表２に示す。EXAMPLES Examples of low loss ferrite for liquid crystal backlight according to the present invention will be described below. First, Fe 2 O 3 ,
Predetermined amounts of MnO and ZnO were calcined and calcined at 900 ° C., and CaO (added with CaCO 3 ), SiO 2 and Co as auxiliary components.
Predetermined amounts of O, Nb 2 O 5 and Ta 2 O 5 were added, the mixture was pulverized with a ball mill for 12 hours, and 1 wt% of a binder was added to carry out spray granulation. This was molded and fired at a holding temperature of 1300 ° C. for 5 hours to manufacture a ring-shaped core (sample) having an outer diameter of 25 mm, an inner diameter of 15 mm and a height of 5 mm. The components of each sample are shown in Table 1. Table 2 shows the minimum value of power loss of each sample, the temperature at that time (bottom temperature), the initial magnetic permeability, the sintered density and the average crystal grain size.
【０００７】[0007]
【表１】 [Table 1]
【０００８】[0008]
【表２】 [Table 2]
【０００９】表１、２において、本発明の範囲外のもの
には、試料の番号に＊印を付けた。試料番号２０では、
Ｆｅ2Ｏ3が５４．８モル％と多く、ボトム温度が０℃と
なり、又試料番号１７では、Ｆｅ2Ｏ3が５２．８モル％
と少ないと、ボトム温度が８０℃となっている。更に、
試料番号１６では、ＣｏＯが８０００ｐｐｍと多く、ボ
トム温度が０℃となり、又試料番号１２では、ＣｏＯが
０ｐｐｍと含有されてなく、ボトム温度が７０℃となっ
ている。このように、Ｆｅ2Ｏ3が５３．０〜５４．５モ
ル％で、ＣｏＯが１００〜４０００ｐｐｍであると、ボ
トム温度が２０〜６０℃となっている。本発明の実施例
によれば、電力損失の最小値が４００ｋＷ／ｍ3以下
で、しかもその最小値となる温度（ボトム温度）が２０
〜６０℃となっている。In Tables 1 and 2, those outside the scope of the present invention are marked with * in the sample numbers. For sample number 20,
Fe 2 O 3 was as large as 54.8 mol%, the bottom temperature was 0 ° C., and in Sample No. 17, Fe 2 O 3 was 52.8 mol%.
If it is less, the bottom temperature is 80 ° C. Furthermore,
In Sample No. 16, CoO is as high as 8000 ppm and the bottom temperature is 0 ° C., and in Sample No. 12, CoO is not contained at 0 ppm and the bottom temperature is 70 ° C. Thus, when Fe 2 O 3 is 53.0 to 54.5 mol% and CoO is 100 to 4000 ppm, the bottom temperature is 20 to 60 ° C. According to the embodiment of the present invention, the minimum value of the power loss is 400 kW / m 3 or less, and the minimum value (bottom temperature) is 20.
It is ~ 60 ° C.
【００１０】[0010]
【発明の効果】本発明によれば、電力損失の最小値が４
００ｋＷ／ｍ3以下で、その電力損失の最小値を得る温
度が２０〜６０℃の電源用低損失フェライトを得ること
が出来、例えば、液晶バックライト用トランスなどの用
途に極めて有効である。According to the present invention, the minimum value of power loss is 4
It is possible to obtain a low-loss ferrite for a power source having a temperature of 20 to 60 ° C. at which the minimum value of power loss is obtained at 00 kW / m 3 or less, and it is extremely effective for applications such as a liquid crystal backlight transformer.
Claims (2)
ＺｎＯ ６〜１２モル％、残部ＭｎＯからなる主成分
と、副成分として、ＣａＯ ２００〜１０００ｐｐｍ、
ＳｉＯ2 ０〜３００ｐｐｍ（但し０ｐｐｍを含まな
い）、ＣｏＯ １００〜４０００ｐｐｍ含有し、更にＮ
ｂ2Ｏ5、Ｔａ2Ｏ5の少なくとも１種を５０〜５００ｐｐ
ｍ含有し、１００ｋＨｚ、２００ｍＴでの電力損失が４
００ｋＷ／ｍ3以下で、その電力損失の最小値を得る温
度が２０〜６０℃であることを特徴とする液晶バックラ
イト用低損失フェライト。1. Fe 2 O 3 53.0-54.5 mol%,
ZnO 6-12 mol%, the main component consisting of the balance MnO, and CaO 200-1000 ppm as a sub-component,
SiO 2 0 to 300 ppm (excluding 0 ppm), CoO 100 to 4000 ppm, and N
50 to 500 pp of at least one of b 2 O 5 and Ta 2 O 5
m, and the power loss at 100kHz, 200mT is 4
A low-loss ferrite for a liquid crystal backlight, wherein the temperature at which the minimum value of the power loss is obtained is 20 to 60 ° C. at 00 kW / m 3 or less.
１５μｍであることを特徴とする液晶バックライト用低
損失フェライト。2. The average crystal grain size according to claim 1, which is 5 to 5.
A low loss ferrite for a liquid crystal backlight, which has a thickness of 15 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15733495A JP3849808B2 (en) | 1995-06-23 | 1995-06-23 | Low loss ferrite for LCD backlight |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15733495A JP3849808B2 (en) | 1995-06-23 | 1995-06-23 | Low loss ferrite for LCD backlight |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH092866A true JPH092866A (en) | 1997-01-07 |
| JP3849808B2 JP3849808B2 (en) | 2006-11-22 |
Family
ID=15647430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15733495A Expired - Lifetime JP3849808B2 (en) | 1995-06-23 | 1995-06-23 | Low loss ferrite for LCD backlight |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3849808B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001080952A (en) * | 1999-09-09 | 2001-03-27 | Tdk Corp | Magnetic ferrite material |
| US6905629B2 (en) | 2002-09-02 | 2005-06-14 | Tdk Corporation | Mn-Zn ferrite, transformer magnetic core and transformer |
| JP2006151701A (en) * | 2004-11-25 | 2006-06-15 | Hitachi Metals Ltd | Manganese-zinc-based ferrite and electronic component using it |
-
1995
- 1995-06-23 JP JP15733495A patent/JP3849808B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001080952A (en) * | 1999-09-09 | 2001-03-27 | Tdk Corp | Magnetic ferrite material |
| EP1083158A3 (en) * | 1999-09-09 | 2001-10-10 | TDK Corporation | Magnetic ferrit material |
| US6905629B2 (en) | 2002-09-02 | 2005-06-14 | Tdk Corporation | Mn-Zn ferrite, transformer magnetic core and transformer |
| JP2006151701A (en) * | 2004-11-25 | 2006-06-15 | Hitachi Metals Ltd | Manganese-zinc-based ferrite and electronic component using it |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3849808B2 (en) | 2006-11-22 |
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