JPS6315221A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a colored display having a high luminance by allowing a luminous phosphor to emit a light beam by ultraviolet rays which are emitted from an ultraviolet ray emitting source. CONSTITUTION:The titled device is provided with a liquid crystal cell, an ultraviolet ray emitting source 39 which is placed in the back side of this liquid crystal cell, and a luminous phosphor 36 which has been placed on an optical path of ultraviolet rays emitted from this ultraviolet ray emitting source 39. By driving a desired TFT 22 by driving a driving circuit board, and setting a picture element in this position, to an applied state, a liquid crystal 33 in this position is set to a light transmissive state. On the other hand, in the ultraviolet emitting source 39, ultraviolet rays are emitted, and this ultraviolet rays are made incident on the luminous phosphor 36 through an ultraviolet ray transmission visible light reflecting filter glass substrate 34. When the ultraviolet rays from the ultra violet ray emitting source 39 are made incident, the ultraviolet rays themselves are colored by the luminous phosphor 36 for emitting the light beams of the respective colors, therefore, the colored light beam of almost the same quantity as the light quantity of the ultraviolet rays emitted from the ultraviolet ray emitting source 39 can be obtained in the surface side. In such a way, a color display having a high luminance is obtained.

Description

[Detailed description of the invention] [1] Target of the invention] (Industrial application field) The present invention relates to a colored liquid crystal display 1. The present invention relates to a colored liquid crystal display 1.

(Prior Art) Generally, a color liquid crystal display device has a structure shown in FIG.

That is, as shown in the figure, a large number of pixel electrodes 2 . . . connected to T'FTs (not shown) are formed on one surface of the first glass substrate 1. On the other hand, on the second glass substrate 3, a red filter R1, a green filter G, and a blue filter B are sequentially formed for each pixel (hereinafter simply referred to as "color filter 4"), and a protective film 5 is formed thereon. A common electrode 6 made of a transparent conductive film is further formed thereon. And for each pixel (mutual electrode 2 and common electrode 6
A first glass substrate 1 and a second glass substrate 3 are arranged with a spacer 7 in between so that they face each other with a predetermined gap, and a liquid crystal 8 is sealed in the gap. In addition, polarizing plates 9 and 10 are arranged on both sides of these, and light sources 11 are arranged on the back side, and drive circuit boards 12 are electrically connected to the TFTs and the common electrode 6. .

Then, by driving the drive circuit board 12 side, a desired pixel electrode 2 is driven, and the pixel at this position is brought into an applied state, thereby making the liquid crystal 8 at this position capable of transmitting light. That is, at this position, the light emitted from the light source 11 passes through the polarizing plate 10, the second glass substrate 3, the color filter 4, the protective film 5, the common electrode (Φ6, the liquid crystal 8, the pixel electrode (*
2. By transmitting the light to the front side through the first glass substrate 1 and the light plate 9, a colored pixel display can be obtained.

(Problems to be Solved by the Invention) The color filter 4 described above has spectral characteristics for each color, for example, as shown in FIG. 19. On the other hand, the light source 11 generally has spectral characteristics as shown in FIG. 20 in addition to the above-mentioned spectral characteristics.

However, even when the spectral characteristics of the light source 11 are matched to the spectral characteristics of the color filter 4 as described above, the light from the light source 11 that has passed through the color filter 4 is
The amount of light is about 174 to 115 compared to the amount of light when emitting light in No. 1. Therefore, there is a problem in that the brightness of the display pixels decreases.

The present invention has been made in response to the above-mentioned circumstances, and an object of the present invention is to provide a liquid crystal display device that can provide a high-luminance color display.

[Structure of the Invention] (Means for Solving the Problems) In other words, the liquid crystal display device of the present invention includes a liquid crystal hill, an ultraviolet light emitting source disposed on the back side of the liquid crystal cell, and a light emitting source from the ultraviolet light emitting source. A light-emitting phosphor is disposed on the optical path of the emitted ultraviolet light.

(Function) In the liquid crystal display device of the present invention, a high-brightness color display can be obtained by causing the light-emitting phosphor to emit light with ultraviolet light emitted from the ultraviolet light source.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

FIG. 1 shows a groove path of a liquid crystal display device according to an embodiment of the present invention.

That is, as shown in the figure, a large number of pixels 11i21, . . . are formed on one surface of the first glass substrate 20. As shown in FIG. 2, a TPT 22 is arranged close to each of these pixel electrodes 21. As shown in FIG. This T
The FT 22 has a gate electrode 23 made of Cr connected to the drive circuit on the first glass substrate 20, a gate insulating film 24 made of SiOx, a semiconductor m25 made of α-3i, and a drain made of Aβ connected to the drive circuit. A source electrode 27 connected to the electrode 26 and the pixel electrode 21 and a PI (polyimide) protective film 28 are sequentially laminated, and a light shielding mask 29 made of 8β is inserted into the protective film 28 so as to cover the lower layer. .

On the other hand, the second glass substrate 30 has a thickness of 70 to 500 μm.
On one side of this, a common conductor (*31) made of a transparent conductive film is adhered using a silicone adhesive.

Then, the first glass substrate 20 and the second glass substrate 30 are arranged with a spacer 32 in between so that the pixel electrode 21 and the common electrode 31 face each other with a predetermined gap, and a liquid crystal 33 is placed in the gap. is included.

Further, an ultraviolet transmitting and visible light repulsion filter glass substrate 34 is disposed on the side of the second glass substrate 30 that is used.

This ultraviolet transmitting visible light filter glass substrate 34 consists of ZnS and SiO2 alternately arranged on a quartz glass plate with a thickness of 0.05 μm.
It is made up of 20 vacuum layers with a thickness of m, and has the spectral characteristics shown in FIG. Also on this is 3MO・1.
2~IC! Q2・019P205 ・0.08 B20
3/EU' (M=Sr, Ca, Ba) and has the spectral characteristics shown in FIG. 4. Blue-emitting phosphor B-1Y
2 S i Os /Ce, Tb and a green-emitting phosphor G' having the spectral characteristics shown in FIG. 5 and YzO3/
The red light-emitting phosphor R', which is made of Fu and is used to emit light as shown in FIG.
It is called "light-emitting phosphor 36". ), 3
7 is attached using a silicone adhesive.

Then, the polarizing plate 37 and the second glass substrate 30 are fixed with a silicone adhesive, and the polarizing plate 38 is attached on the surface of the first glass substrate 20 with a silicone adhesive, and then on the back side. A plurality of ultraviolet light emitting sources 39 having spectral properties shown in FIG. 7 are arranged at predetermined intervals.

In the liquid crystal display device configured in this manner, the desired lower FT 22 is driven by driving the drive circuit board (not shown), and the pixel at this position is brought into an applied state.
The liquid crystal 33 at this position is brought into a light transmittable state. on the other hand,
The ultraviolet light source 39 emits ultraviolet light, and the ultraviolet light enters the light-emitting phosphor 36 via the ultraviolet-transmissive visible light-repellent filter glass substrate 34 . This light-emitting phosphor 36 itself emits light corresponding to each color by receiving light from the outside line. In other words, at the position where the light from the liquid crystal 33 is enabled, the colored light from the light emitting phosphor 36 is directed to the polarizing plate 37, the second glass substrate j○, the common electrode 31, and the liquid crystal 3.
3. By transmitting light to the front side through the pixel electrode (fish 21, first glass substrate 20, and polarizing plate 38), colored light, that is, a colored display can be obtained.

However, according to this embodiment, when the ultraviolet light from the ultraviolet light source 39 enters, it is colored by the light-emitting phosphors 36 that emit light of respective colors, so that the ultraviolet light emitted from the ultraviolet light source 39 is colored. Colored light of approximately the same amount as the amount of ultraviolet rays can be obtained on the front side, that is, a high-luminance color display can be obtained.

Next, a method for forming the light-emitting phosphor 36 in this example will be described below.

First, a resist IIQ made of photosensitive milk casein is formed on the ultraviolet transmitting and visible light reflecting filter glass substrate 34,
After exposure using the same mask as the desired pattern, development is performed to dissolve and remove the unexposed portions. After that, apply Aquadag containing the specified materials to the remaining Regime 1 with a processing solution mainly consisting of Aquadag (washed and dried, water-soluble peroxide), and remove this resist film along with unnecessary Aquadag on the film. A desired black matrix pattern 35 is obtained.

Next, for the blue light emitting phosphor B-, 3MO・1.2
MCJh ・0.9P20s” 0.08B
203 / E u2 (M = Sr, Ca, Ba>) is dispersed in photosensitive milk casein to form a fluorescent film B', exposed to light using the same mask as the desired pattern, dried, and developed to remove unexposed areas. is removed to form the B' luminescent fluorescent film (Q).

This process is sequentially applied to the green light-emitting phosphor G-, and then to Y25.
iOs/Cc, Tb, Y in the red-emitting phosphor R'
2O3/Eu is repeatedly coated with a desired light-emitting fluorescent film.

In addition, the above-mentioned ultraviolet transmitting visible light filter glass substrate 3
4, Pyrex or any multilayer film of ZnS and MQF2 may be used, that is, it has a transmittance of 50% or more in the wavelength range of 350 to 3701 m for ultraviolet rays, and 30% or more in the wavelength range of 400 nm for visible light. % or more, 4
It has a recoil ratio of 60% or more at 30 to 650 nm and 20% or more at 7000 m.

The light-emitting phosphor 36 may be either inorganic or organic. For example, in the case of an inorganic light-emitting phosphor, a blue light-emitting phosphor is made of ZnS/AQ and has the spectral characteristics shown in FIG. The light-emitting phosphor is made of Zn2Si04/Mr) and has the spectral characteristics shown in Figure 9, and 7nS/Cu, AJ2 has the spectral characteristics shown in Figure 10 [1 or ZnCd5/Cu, A! Q and has the spectral 12+ characteristics shown in Figure 11, red light-emitting phosphors include Y202S/EU and have the spectral characteristics shown in Figure 12, or YVO4/Fu, T
b, YVS i04 /Eu, Tb, YVPS i O
+/Eu, Tb and -C may be used, or a mixture of these within the same color may be used.

Next, a modification of this embodiment is shown in FIG. 1. As shown in the same figure, a germicidal lamp 40 having a spectral characteristic of 1 as shown in FIG. Since it is an IT system, it is possible to obtain the same effect as the embodiment described above.

In this case, as the ultraviolet light emitting phosphor 41, (c
a, zn> 3 (PO2)2/T℃ system/)"B'
:,; In this case, as the ultraviolet light emitting light source 40, it is preferable to use a material that has the spectral characteristics shown in FIG. , has an emission peak at a wavelength of 250 to 370 nm, and has a wavelength of 420 to 480 nm as a blue-emitting phosphor.
510~ as a green-emitting phosphor with an emission peak at m.
Optimal is a red light-emitting phosphor having an emission peak at 560 nm and an emission peak at 600 to 660 nm. Incidentally, on the light-emitting phosphor, for example, a C'oOe AJ2203 pigment may be attached to a blue-emitting phosphor, and a Fe201 pigment may be attached to a red-emitting phosphor.

Further, according to the above-described embodiment, the ultraviolet-transmitting visible light-reflecting filter glass substrate 34 was disposed between the light-emitting phosphor and the light source, but the present invention is not limited to this, for example. It may be an ultraviolet transmitting/visible light cutting filter glass substrate having the spectral characteristics shown in FIG. 17, or it may be a simple glass substrate.

[Effects of the Invention] As explained above, according to the liquid crystal display device of the present invention, it is possible to perform high-luminance color display.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal sectional front view showing a liquid crystal display device according to an embodiment of the present invention, Fig. 2 is a partially enlarged view thereof, and Fig. 3 is a spectral characteristic of a glass substrate of this embodiment. FIG. 4 is a diagram showing the spectral characteristics of the blue-emitting phosphor of this example, FIG. 5 is a diagram showing the spectral characteristics of the green-emitting phosphor of this example, and FIG. 6 is a diagram showing the spectral characteristics of the green-emitting phosphor of this example. FIG. 7 is a diagram showing the spectral characteristics of the red-emitting phosphor, FIG. 7 is a diagram showing the spectral characteristics of the ultraviolet light source of this example, FIG. 8 is a diagram showing the spectral characteristics of other blue-emitting phosphors, and FIGS. Figure 11 is a diagram showing the spectral characteristics of other green-emitting phosphors.
Figure 2 is a diagram showing the spectral characteristics of other red-emitting phosphors;
14 is a diagram showing the spectral characteristics of a germicidal lamp in a modified example of the present invention, and FIG.
16 and 16 are diagrams showing the spectral characteristics of the ultraviolet light emitting phosphor in this modified example, FIG. 17 is a diagram showing the spectral characteristics of the ultraviolet transmitting visible light cut filter glass substrate in the second example of the present invention, and FIG. 19 is a longitudinal sectional front view showing a conventional liquid crystal display device, FIG. 19 is a diagram showing spectral characteristics of a color filter of this liquid crystal display device, and FIG. 20 is a diagram showing spectral characteristics of a light source of this liquid crystal display device. 36......Light-emitting phosphor 39......Ultraviolet light emitting source Applicant Toshiba Corporation Agent Patent attorney Sa Suyama - Wavelength (nm) Figure 3 Wavelength (nm) Wavelength (nm) Figure 5: Liquid length (nm) Figure 7: Wavelength (nml) Figure 8: Wavelength (nm) Figure 9: Wavelength (nm) Figure 10: Liquid length (nm) 11th Figure 13: Wavelength (nm) Figure 17: Wavelength (nm) Figure 19: Wavelength (nm)

Claims (2)

[Claims] (1) It is characterized by comprising a liquid crystal cell, an ultraviolet light source placed on the back side of the liquid crystal cell, and a light emitting phosphor placed on the optical path of the ultraviolet light emitted from the ultraviolet light source. A liquid crystal display device. (2) The liquid crystal display device according to claim 1, wherein the light-emitting phosphor is a red-light-emitting phosphor, a green-light-emitting phosphor, and a blue-light-emitting phosphor arranged sequentially in each pixel of the liquid crystal cell.