Liquid crystal display
View Patent ↗A liquid crystal display capable of expanding a color reproduction range in the case where a cold cathode fluorescent lamp is used as a light source is provided. A green phosphor of the cold cathode fluorescent lamp includes BaMgAl 10 O 17 :Eu, Mn. The wavelength range of a green emission spectrum is located on a shorter wavelength side than that in the case where the green phosphor includes LaPO 4 :Ce, Tb, so the spectral width of the green emission spectrum is narrower. Therefore, an overlap between the wavelength ranges of green display light and red display light is reduced. Moreover, the spectral characteristics of blue display light (blue spectral characteristics) are set so as to satisfy predetermined conditional expressions. An overlap between the wavelength ranges of the green display light and the blue display light is also reduced.
1. A liquid crystal display, comprising:
a cold cathode fluorescent lamp including a red phosphor, a green phosphor and a blue phosphor and emitting white light, the green phosphor including BaMgAl 10 O 17 :Eu, Mn and the blue phosphor including BaMgAl 10 O 17 :Eu; and
a liquid crystal panel modulating the white light according to an image signal to emit the modulated white light as a display light,
wherein assuming that the maximum peak intensity is Pbmax, the peak intensity at a wavelength of 506 nm is Pb(506 nm), the peak intensity at a wavelength of 530 nm is Pb(530 nm), and the peak intensity at a wavelength of 550 nm is Pb(550 nm), in blue spectral characteristics of the display light, Pbmax, Pb(506 nm), Pb(530 nm) and Pb(550 nm) satisfy the following conditional expressions (1) through (3):
Pb (506 nm)/ Pb max≦0.550 (1)
Pb (530 nm)/ Pb max≦0.100 (2)
Pb (550 nm)/ Pb max≦0.025 (3).
2. The liquid crystal display according to claim 1 , wherein
the liquid crystal panel includes a blue color filter selectively allowing only light in a blue wavelength range of the white light modulated according to the image signal to pass through, and
the blue color filter is formed so as to satisfy the conditional expressions (1) through (3).
3. The liquid crystal display according to claim 2 , wherein
the blue color filter includes Pigment Blue (P.B. 15:6) as a blue pigment and Pigment Violet (P.V.23) as a violet pigment, and
the content ratio between Pigment Blue (P.B. 15:6) and Pigment Violet (P.V.23) is within a range from 3:7 to 4:6.
4. The liquid crystal display according to claim 2 , wherein
the thickness of the blue color filter is adjusted so as to satisfy the conditional expressions (1) through (3).
5. The liquid crystal display according to claim 1 , further comprising:
an adjustment layer between the cold cathode fluorescent lamp and the liquid crystal panel or in the liquid crystal panel so as to adjust the spectral characteristics of the white light and guide the adjusted white light to the liquid crystal panel,
wherein the adjustment layer is formed so as to satisfy the conditional expressions (1) through (3).
6. The liquid crystal display according to claim 5 , wherein
the adjustment layer is a diffusing plate, the transmittance of the diffusing plate being adjusted so as to satisfy the conditional expressions (1) through (3).
7. The liquid crystal display according to claim 1 , wherein
the red phosphor includes YVO 4 :Eu or Y(P,V)O 4 :Eu.
8. The liquid crystal display according to claim 1 , wherein
the red phosphor includes Y 2 O 3 :Eu, and
assuming that the maximum peak intensity is Prmax, the peak intensity at a wavelength of 580 nm is Pr(580 nm), and the peak intensity at a wavelength of 600 nm is Pr(600 nm), in the red spectral characteristics of the display light, Prmax, Pr(580 nm) and Pr(600 nm) satisfy the following conditional expressions (4) and (5):
Pr (580 nm)/ Pr max≦0.200 (4)
Pr (600 nm)/ Pr max≦0.850 (5).
9. The liquid crystal display according to claim 8 , wherein
the liquid crystal panel includes a red color filter selectively allowing only light in a red wavelength range of the white light modulated according to the image signal to pass through, and
the red color filter is formed so as to satisfy the conditional expressions (4) and (5).