GLASS COMPOSITION FOR LAMP, LAMP, BACKLIGHT UNIT AND METHOD FOR PRODUCING GLASS COMPOSITION FOR LAMP

1 . A glass composition for lamps which contains Mo ions as a component, substantially comprising the following that are expressed in terms of oxides:

SiO 2 : 55 to 75 wt %;

B 2 O 3 : 11 to 25 wt %;

MoO 3 : 0.3 to 1.4 wt %;

Al 2 O 3 : 1 to 10 wt %;

Li 2 O: 0 to 10 wt %;

Na 2 O: 0 to 10 wt %;

K 2 O: 0 to 10 wt %;

Li 2 O+Na 2 O+K 2 O: 1 to 10 wt %;

MgO: 0 to 5 wt %;

CaO: 0 to 10 wt %;

SrO: 0 to 10 wt %;

BaO: 0 to 10 wt %; and

MgO+CaO+SrO+BaO: 1 to 10 wt %, wherein

a cation percentage of Mo 6+ and Mo Other of the Mo ions satisfies the following relation:

(Mo 6+ )/[(Mo 6+ )+(Mo Other )]≧0.8.

2 . The glass composition of claim 1 , having an oxidization property in a molten state.

3 . The glass composition of claim 1 , containing 1.1 wt % or more MoO 3 in terms of oxides.

4 . The glass composition of claim 2 , containing 1.1 wt % or more MoO 3 in terms of oxides.

5 . The glass composition of claim 1 , wherein

a thermal expansion coefficient α 30/380 is in a range of 34×10 −7 /K to 43×10 −7 /K inclusive.

6 . The glass composition of claim 4 , wherein

a thermal expansion coefficient α 30/380 is in a range of 34×10 −7 /K to 43×10 −7 /K inclusive.

7 . The glass composition of claim 1 , wherein

a thermal expansion coefficient α 30/380 is in a range of 43×10 −7 /K to 55×10 −7 /K inclusive.

8 . The glass composition of claim 4 , wherein

a thermal expansion coefficient α 30/380 is in a range of 43×10 −7 /K to 55×10 −7 /K inclusive.

9 . A lamp including a glass bulb that is made of the glass composition of claim 1 .

10 . A lamp including a glass bulb that is made of the glass composition of claim 3 .

11 . A backlight unit on which the lamp of claim 9 is disposed.

12 . A backlight unit comprising:

a plurality of lamps of claim 10 ; and

a diffusion plate made from a polycarbonate resin disposed on a light-emission side of the plurality of lamps.

13 . A method for producing a glass composition for lamps comprising:

a mixing step of mixing glass materials so that the glass composition substantially contains the following that are expressed in terms of oxides:

SiO 2 : 55 to 75 wt %;

B 2 O 3 : 11 to 25 wt %;

MoO 3 : 0.3 to 1.4 wt %;

Al 2 O 3 : 1 to 10 wt %;

Li 2 O: 0 to 10 wt %;

Na 2 O: 0 to 10 wt %;

K 2 O: 0 to 10 wt %;

Li 2 O+Na 2 O+K 2 O: 1 to 10 wt %;

MgO: 0 to 5 wt %;

CaO: 0 to 10 wt %;

SrO: 0 to 10 wt %;

BaO: 0 to 10 wt %; and

MgO+CaO+SrO+BaO: 1 to 10 wt %; and

a melting step of melting the mixed glass materials to make the glass composition in a molten state, wherein

the glass materials in the molten state are oxidized in the melting step.

14 . The method of claim 13 , wherein

a part of the glass materials mixed in the mixing step is alkali metal nitrate, and

the glass materials in the molten state are oxidized in the melting step by melting the alkali metal nitrate.

15 . The method of claim 13 , wherein

the alkali metal nitrate is either NaNO 3 or KNO 3 , or both NaNO 3 and KNO 3 .

16 . The method of claim 14 , wherein

the alkali metal nitrate is either NaNO 3 or KNO 3 , or both NaNO 3 and KNO 3 .