JPH1020109A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of displaying a high-luminance distinct color image excellent in color purity. SOLUTION: Red, green and blue optical coloring films 40R, 40G and 40B are arranged between a liquid crystal cell 1 and a light source 30 arranged at the rear of the cell 1 corresponding to the respective picture elements of the cell 1, and they are a complex obtained by mixing fluorescent substance having the same stock color as a color filter having a specified color in the color filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display for displaying a color image.

[0002]

2. Description of the Related Art Conventionally, as a liquid crystal display device for displaying a color image, a liquid crystal cell provided with a plurality of color filters (generally, three color filters of red, green and blue) respectively corresponding to respective pixels. There is known a configuration in which a light source is arranged behind the light source.

[0003]

However, since the above-mentioned liquid crystal display device obtains colored light using a color filter, the color purity of a displayed color image is good, but the brightness of the image is not sufficient. I have a problem.

This is because the color filter transmits light in the wavelength range of the color and absorbs light in the other wavelength range, so that light from the light source is largely absorbed by the color filter, and the liquid crystal cell is damaged. This is because the intensity of the emitted colored light is considerably reduced. SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device capable of displaying a clear color image with high luminance and good color purity.

[0005]

A liquid crystal display device according to the present invention comprises a liquid crystal cell, a light source disposed behind the liquid crystal cell, and a light-colored film of a plurality of colors corresponding to each pixel of the liquid crystal cell. And the light-colored films of the respective colors are respectively
It is characterized by comprising a complex of a color filter of a predetermined color and a fluorescent substance of a similar color to the color filter.

That is, in the liquid crystal display device of the present invention, colored light is obtained by a light colored film made of a complex of a color filter of a predetermined color and a fluorescent substance of a similar color to the color filter. When light is incident, the fluorescent substance absorbs excitation light in a wavelength range different from that of the fluorescent color and emits fluorescence of a color unique to the fluorescent substance due to its energy. The light is emitted as light having an intensity distribution in which the light intensity in the wavelength region of the fluorescent color unique to the fluorescent substance is increased.

The color filter of the light-coloring film transmits light in the wavelength range of the color and absorbs light in other wavelength ranges, but the fluorescent light emitted by the fluorescent substance has a similar color to the color filter. Further, since the light incident on the color filter is light having an intensity distribution in which the light intensity in the wavelength range transmitting the color filter is increased, the light transmitted through the color filter, that is, the color emitted from the light-colored film is colored. The light intensity is higher at each stage than when the light is colored only with the color filters. Moreover, since the colored light emitted from the light colored film is light in a wavelength range transmitted through the color filter, the color purity is good.

Therefore, according to the liquid crystal display device of the present invention, it is possible to emit colored light having sufficient intensity on the surface side of the liquid crystal cell, and to display a clear color image with high luminance and good color purity. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the liquid crystal display device of the present invention comprises a plurality of light-colored films corresponding to respective pixels of a liquid crystal cell, each having a predetermined color filter and a similar color filter. By forming a complex with a fluorescent substance, this light-colored film can provide colored light with high intensity and good color purity.

In the liquid crystal display device according to the present invention, the light-colored film of each color may be a color filter in which a fluorescent substance is mixed or a color filter and a phosphor film made of a fluorescent substance may be laminated. When using the latter light colored film, this light colored film,
What is necessary is just to arrange | position the phosphor film toward the light source side.

In the liquid crystal display device according to the present invention,
The light-colored film of each color may be disposed between a light source and a liquid crystal cell, or may be provided on an inner surface of one of a pair of substrates of the liquid crystal cell, or a surface of the liquid crystal cell. Although the most preferable location of the light-colored film is between the light source and the liquid crystal cell, if the light-colored film is disposed between the light source and the liquid crystal cell, Since light first enters the light-colored film, the light from the light source is most efficiently received by the fluorescent substance of the light-colored film to generate stronger colored fluorescence, and the intensity of the colored light emitted from the light-colored film is further increased. By increasing the height, the intensity of the colored light emitted to the surface side of the liquid crystal cell can be further increased.

Further, the present invention can be applied to a so-called projection type liquid crystal display device having a projection means for enlarging and projecting the light emitted from the liquid crystal cell. If the light colored film is disposed between the light source and the liquid crystal cell as described above, the intensity of the colored light emitted to the surface side of the liquid crystal cell can be further increased. Even if the brightness is reduced due to the projection by the projection means, the brightness and the sharpness of the enlarged image projected and displayed on the projection surface such as a screen can be sufficiently increased.

[0013]

【Example】

FIG. 1 is a sectional view of a part of a liquid crystal display device according to a first embodiment of the present invention. This liquid crystal display device is of a TN (twisted nematic) type, and includes a liquid crystal cell 1, a pair of polarizing plates 21 and 22 sandwiching the liquid crystal cell 1, and a liquid crystal cell 1 disposed behind the liquid crystal cell 1. Light source 30, the light source 30 and the liquid crystal cell 1
And a plurality of light-colored films 40R, 40G, and 40B of three colors, for example, red, green, and blue, arranged corresponding to the respective pixels of the liquid crystal cell 1 in this embodiment. In this embodiment, the light colored films 40R, 40G, and 40B are disposed between the light source 30 and the back-side polarizing plate 21 disposed on the back side of the liquid crystal cell 1.

First, the liquid crystal cell 1 will be described. The liquid crystal cell 1 is of an active matrix type, and a rear substrate (of a pair of transparent substrates 2 and 3 opposed to each other with a liquid crystal layer 14 interposed therebetween). (The lower substrate in the figure)
2, a plurality of transparent pixel electrodes 4 and a plurality of switching elements 5 corresponding to the respective pixel electrodes 4 are formed in a matrix in a row and column direction. An alignment film 11 that has been subjected to an alignment process is formed.

The switching element 5 is, for example, a TFT
(Thin film transistor), and the TFT 5
A gate electrode 6 formed thereon, a gate insulating film 7 covering the gate electrode 6, a semiconductor film 8 formed on the gate insulating film 7 so as to face the gate electrode 6, and provided on both sides thereof Source electrode 9 and drain electrode 10
It consists of The gate insulating film 7 is a transparent film, and is formed over the entire display area of the liquid crystal cell 1.

Although not shown, a gate line (address line) for supplying a gate signal to the gate electrode 6 of the TFT 5 is provided on the inner surface of the back substrate 2.
A data line for supplying a data signal according to image data is connected to the drain electrode 10 of the fifth embodiment.

The gate line is formed on the substrate 2 by the T
It is formed integrally with the gate electrode 6 of the FT 5 and is covered with the gate insulating film 7 except for its terminal. Further, a data line is formed on the gate insulating film 7, and the data line is connected to the drain electrode 1 of the TFT 5.
Connected to 0.

The pixel electrodes 4 are formed on the gate insulating film 7, and each pixel electrode 4 is
One end is connected to the source electrode 9 of the corresponding TFT 5.

On the other hand, on the inner surface of the front substrate 3 (upper substrate in the figure) 3 of the liquid crystal cell 1, a single film-shaped transparent counter electrode 12 facing each pixel electrode 4 of the back substrate 2 is formed. In addition, an alignment film 13 that has been subjected to an alignment process is formed thereon.

Although not shown, the back substrate 2 and the front substrate 3 are joined at their outer peripheral edges via a frame-shaped sealing material, and the liquid crystal 14 is sealed between the substrates 2 and 3. It is enclosed in the area surrounded by the material.

The liquid crystal 14 is a nematic liquid crystal having a positive dielectric anisotropy, and its molecules are formed in the vicinity of the substrates 2 and 3 by the alignment films 11 and 13 provided on the inner surfaces of the substrates 2 and 3. Is twisted at a predetermined twist angle between the substrates 2 and 3.

The twist angle of the liquid crystal molecules is, for example, about 90 °, and the rear polarizing plate 21 of the pair of polarizing plates 21 and 22 has its transmission axis set near the rear substrate 2 of the liquid crystal cell 1. And the polarizing plate 22 on the front side has its transmission axis substantially aligned with the alignment direction of the liquid crystal molecules in the vicinity of the front substrate 3 of the liquid crystal cell 1. They are arranged in parallel or substantially orthogonally.

The light source 30 is, for example, a surface light source generally called a side lamp type.
A light guide plate 31 made of acrylic resin or the like arranged opposite to the back surface of the light guide plate, and a light source lamp (not shown) made of a straight tube fluorescent lamp or the like arranged opposite one end surface or both end surfaces of the light guide plate 31 ).

In this side lamp type light source, light from the light source lamp is guided by a light guide plate 31 as shown by a broken line in FIG. 1 and emitted from the surface thereof. The reflected light is repeatedly reflected on the front and back surfaces of the light guide plate 31 and guided to the entire light guide plate, and light incident on the light guide plate surface at an angle steeper than the total reflection angle is incident on the surface of the light guide plate 31. Outgoing to the side.

On the other hand, the red, green and blue light colored films 40R,
Each of 40G and 40B is formed of a complex of a color filter of a predetermined color and a fluorescent substance of a similar color to the color filter. In this embodiment, the fluorescent substance is made of a transparent resin granular material dyed with a fluorescent dye. These fluorescent pigments are mixed in a color filter in a dispersed state to form light-colored films 40R, 40G, and 40B of each color.

That is, the red light coloring film 40R is made of a red color filter mixed with a red fluorescent pigment.
The green light coloring film 40G is made of a green color filter mixed with a green fluorescent pigment, and the blue light coloring film 40B is
It consists of a blue color filter mixed with a blue fluorescent pigment.

The light coloring films 40R, 40R
G and 40B are alternately arranged and formed on the surface of the light guide plate 31 of the light source 30. By adjusting the arrangement position of the light guide plate 31, the light colored films 40R and 40R of each color are formed.
G and 40B are arranged so as to correspond to the respective pixels of the liquid crystal cell 1 respectively.

In this liquid crystal display device, light from the light source 30 is first made incident on the light colored films 40R, 40G, and 40B to obtain red, green, and blue colored lights.
The light of each color emitted from OG and 40B is incident on each pixel of the liquid crystal cell 1 and the transmission of the light is controlled by a pair of polarizing plates 2 disposed between the liquid crystal cell 1 and the liquid crystal cell 1.
1 and 22 to display a color image. The liquid crystal cell 1 and a pair of polarizing plates 21 and 22
Is the same as that of a general TN liquid crystal display device, and a description thereof will be omitted.

That is, this liquid crystal display device has a red, green, and blue light colored film 40 composed of a composite of a color filter and a fluorescent substance having a similar color (a fluorescent pigment in this embodiment).
R, 40G, and 40B are used to obtain red, green, and blue colored light, and these light colored films 40R, 40G, and 40B are obtained.
When light (white light) from the light source 30 is incident on the fluorescent material, the fluorescent material absorbs excitation light in a wavelength range different from the fluorescent color and emits a fluorescent light of a color specific to the fluorescent material by its energy. The light incident on the light colored films 40R, 40G, and 40B is emitted as light having an intensity distribution in which the light intensity in the fluorescent color wavelength region unique to the fluorescent substance is increased.

Examples of the red, green, and blue fluorescent materials include coumarin102 and coumar as blue fluorescent materials.
in480, coumarin481 etc. The peak value of the absorption wavelength (wavelength of excitation light) and the peak value of the emission wavelength of these fluorescent materials are coumarin102; absorption wavelength peak 390 nm, emission wavelength peak 468 nm coumarin480; absorption wavelength peak 390 nm, emission wavelength peak 466 nm coumarin481 An absorption wavelength peak of 390 nm and an emission wavelength peak of 465 nm, each of which mainly absorbs light in the ultraviolet region and is excited to generate blue fluorescence.

Green fluorescent substances include HPTS and coum.
arin153 etc. The peak values of the absorption wavelength and emission wavelength of these fluorescent substances are HPTS; absorption wavelength peak 455 nm, emission wavelength peak 510 nm coumarin 153; absorption wavelength peak 423 nm, emission wavelength peak 532 nm. Then, it absorbs light in the blue wavelength range and is excited to generate green fluorescence.

Further, as a red fluorescent substance, there is LDS720 or the like. The peak value of the absorption wavelength of this fluorescent substance is 529 nm,
The emission wavelength has a peak value of 699 nm, and is mainly excited by absorbing light in the green wavelength range to generate red fluorescence.

Then, the light colored films 40R, 40 of the respective colors are formed.
The G, 40B color filter transmits light in the wavelength range of the color and absorbs light (excitation light) in the other wavelength range, but the fluorescent light emitted by the fluorescent substance has the same color as that of the color filter. Since the light incident on the color filter is light having an intensity distribution in which the light intensity in the wavelength region transmitted through the color filter is increased, the light transmitted through the color filter, that is, the light colored films 40R, 40G, and 40B are emitted. The intensity of the colored light is higher in each stage than when the light is colored only with the color filter. Moreover, the light colored film 40
Since the colored light emitted from R, 40G, and 40B is light in the wavelength range transmitted through the color filter, the color purity is good.

Therefore, according to the above liquid crystal display device,
By emitting colored light of sufficient intensity to the surface side of the liquid crystal cell 1, a clear color image with high luminance and good color purity can be displayed.

[Second Embodiment] FIG. 2 is a sectional view of a part of a liquid crystal display device according to a second embodiment of the present invention. The liquid crystal display device of this embodiment has a red, green, and blue light coloring film 41.
The red, green and blue color filters 42R, 42G and 42B and the phosphor films 43R, 43G and 43B made of fluorescent substances of the same color as the color filters 42R, 42G and 42B are used as R, 41G and 41B, respectively. It has a laminated two-layer film structure, and other configurations are the same as those of the first embodiment.

The phosphor films 43R, 43G, 43B are
A colorless transparent resin mixed with a fluorescent substance of a predetermined color (for example, a fluorescent pigment).
G and 41B are arranged with their phosphor films 43R, 43G and 43B facing the light source 30 side.

According to this liquid crystal display device, the light (white light) incident on the light colored films 41R, 41G, 41B of the respective colors from the light source 30 first enters the phosphor films 43R, 43G, 43B. The phosphor films 43R, 43G, and 43B are excited to generate fluorescent light of a color unique to each fluorescent substance, and to a colored light having an intensity distribution in which the light intensity in the wavelength region of the fluorescent color specific to the fluorescent substance is increased. Since the light passes through the color filters 42R, 42G, and 42B and becomes colored light having higher color purity, the colored light having higher intensity and color purity than the first embodiment is incident on the liquid crystal cell 1. Thus, a clear color image with higher luminance and good color purity can be displayed.

That is, in the first embodiment, the light-colored films 40R, 4R in which a fluorescent substance is mixed in a color filter are used.
0G and 40B, these light colored films 40
The fluorescent substance near the incident surface of R, 40G, and 40B (the surface facing the light source 30) sufficiently absorbs light in the excitation wavelength region (excitation light) of the incident light to emit high-intensity fluorescence. But,
Since the excitation light of the fluorescent substance near the emission surface is absorbed by the color filter, the excitation light incident on the fluorescent substance near the emission surface is weak. Therefore, the intensity of the fluorescent light emitted from the fluorescent material decreases as the emission surface approaches.

On the other hand, the light colored films 41R, 41G and 41B used in this embodiment are the fluorescent films 43R and 4R.
Since 3G and 43B are made by mixing a fluorescent substance into a colorless transparent resin, there is no excitation light absorption like a color filter, and therefore, a high-intensity fluorescent light is generated in the fluorescent substance near the incident surface. In addition, the fluorescent substance near the emission surface can be sufficiently irradiated with the excitation light of the light (white light) transmitted through the gap between the fluorescent substances near the incident surface to generate high-intensity fluorescent light.

In the light-colored films 40R, 40G, and 40B used in the first embodiment, the fluorescence generated by the fluorescent substance near the emission surface is emitted almost without passing through the color filter. The light colored film 41R used in
According to 41G and 41B, the phosphor films 43R and 43R are provided.
The fluorescent light emitted from G and 43B must be a color filter 42
R, 42G, 42B, and the light-colored films 41R,
Since light in unnecessary wavelength ranges is absorbed by 41G and 41B,
It becomes colored light with good color purity.

Moreover, the light colored films 41R, 4R of this embodiment
1G and 41B, the phosphor films 43R, 43G, 43
B is emitted from the color filter 42 on the emission side.
Since the fluorescent light is of the same color as the colors of R, 42G, and 42B, even if the thickness of the color filters 42R, 42G, and 42B is small, colored light with sufficiently high color purity can be obtained. 42G and 42B need only be formed extremely thin.

[Third Embodiment] FIG. 3 is a sectional view of a part of a liquid crystal display device according to a third embodiment of the present invention. The liquid crystal display device of this embodiment is different from the first embodiment in that the red, green, and blue light-colored films are arranged on the back side of the liquid crystal cell between the liquid crystal cell and the light source. It is arranged between the polarizing plate and other components, and the other configuration is the same as that of the first embodiment.

According to the liquid crystal display device of this embodiment, the light from the light source 30 is first transmitted through the back-side polarizing plate 21 and becomes linearly polarized light, and the light is converted into the light-colored films 40R and 40R of the respective colors.
G, 40B and these light colored films 40R, 40R.
The red, green, and blue lights emitted from G and 40B enter the respective pixels of the liquid crystal cell 1 respectively.

Also in this liquid crystal display device, the red, green, and blue light coloring films 40R, 40G, and 40B corresponding to the respective pixels of the liquid crystal cell 1 are each provided with a color filter of a predetermined color and a color filter of a similar color. By forming a complex with a fluorescent substance, the light-colored films 40R, 40G, and 40B provide colored light with high intensity and good color purity. , And a clear color image with high luminance and good color purity can be displayed.

In this embodiment, since the light transmitted through the back-side polarizing plate 21 is incident on the light-colored films 40R, 40G, and 40B, the intensity of the light incident on the light-colored films 40R, 40G, and 40B is reduced. The intensity of the colored light emitted from the light-colored films 40R, 40G, and 40B is lower than that of the first and second embodiments. Still, since the intensity of the colored light is higher in each stage than in the case where the light is colored only by the color filter, a clear color image with high luminance and good color purity is displayed as compared with the conventional liquid crystal display device. can do.

[Fourth Embodiment] FIG. 4 is a sectional view of a part of a liquid crystal display device according to a fourth embodiment of the present invention. The liquid crystal display device of this embodiment has the red, green, and blue light coloring films used in the first embodiment described above provided on the inner surface of the front substrate of the pair of substrates of the liquid crystal cell. Other configurations are the same as those of the first embodiment.

According to the liquid crystal display device of this embodiment, the light from the light source 30 becomes linearly polarized light after passing through the backside polarizing plate 21, and the light is converted to the backside substrate 2 of the liquid crystal cell 1 and the liquid crystal layer. And the light colored films 40R, 40G, 4
0B, and the light colored films 40R, 40G, 40
It is colored red, green and blue by B and emitted.

Also in this liquid crystal display device, the red, green, and blue light coloring films 40R, 40G, and 40B corresponding to the respective pixels of the liquid crystal cell 1 are each provided with a color filter of a predetermined color and a color filter of a similar color. By forming a complex with a fluorescent substance, the light-colored films 40R, 40G, and 40B provide colored light with high intensity and good color purity. , And a clear color image with high luminance and good color purity can be displayed.

In this embodiment, the light from the light source 30 passes through the back-side polarizing plate 21 to have almost half the intensity, and furthermore, a certain amount of light is transmitted in the process of passing through the back-side substrate 2 of the liquid crystal cell 1 and the liquid crystal layer. The light colored film 40R of each color absorbed and
40G and 40B, these light-colored films 40
Although the intensity of the colored light emitted from R, 40G, and 40B is somewhat weaker than that of the third embodiment described above, the intensity of the colored light is still lower in each stage than when the light is colored only by the color filter. Therefore, a clear color image with high luminance and good color purity can be displayed as compared with a conventional liquid crystal display device.

However, in the above embodiment, the light colored film 4
Although 0R, 40G, and 40B are provided on the inner surface of the front substrate 3 of the liquid crystal cell 1, the light coloring films 40R, 40G, and 40B
It may be provided on the inner surface of the back substrate 2 of the liquid crystal cell 1, and in this case, the light-colored films 40R, 40R
G, 40B, by increasing the intensity of the light incident on the light-colored films 40R, 40B by the amount of light absorbed during the transmission through the liquid crystal layer.
The intensity of the colored light emitted from G and 40B can be improved.

[Fifth Embodiment] FIG. 5 is a sectional view of a part of a liquid crystal display device according to a fifth embodiment of the present invention. The liquid crystal display device of this embodiment includes the red, green, and blue light coloring films used in the first embodiment described above on the surface of the liquid crystal cell, that is, the liquid crystal cell and the front side polarizing plate disposed on the surface side. The other components are the same as those of the first embodiment.

According to the liquid crystal display device of this embodiment, the light from the light source 30 is first converted into linearly polarized light through the back-side polarizing plate 21, and the light is transmitted through the liquid crystal cell 1 to emit light of each color. The light is incident on the colored films 40R, 40G, and 40B, and is colored red, green, and blue by the light colored films 40R, 40G, and 40B, and is emitted.

Also in this liquid crystal display device, the red, green, and blue light coloring films 40R, 40G, and 40B corresponding to the respective pixels of the liquid crystal cell 1 are each provided with a color filter of a predetermined color and a color filter of a similar color. By forming a complex with a fluorescent substance, the light-colored films 40R, 40G, and 40B provide colored light with high intensity and good color purity. , And a clear color image with high luminance and good color purity can be displayed.

In this embodiment, the light from the light source 30 passes through the back-side polarizing plate 21 to have almost half the intensity, and the back substrate 2 and the liquid crystal layer of the liquid crystal cell 1 and the front substrate 3
In the process of transmitting the light, the light is absorbed to some extent and enters the light-colored films 40R, 40G, and 40B of the respective colors. Therefore, the intensity of the colored light emitted from these light-colored films 40R, 40G, and 40B is increased in the fourth embodiment. Somewhat weaker than the example,
Nevertheless, since the intensity of the colored light is higher in each stage than in the case where the light is colored only with the color filter, a clear color image with high luminance and good color purity is displayed as compared with the conventional liquid crystal display device. be able to.

[Other Embodiments] The first to fifth embodiments described above
In any of the liquid crystal display devices according to the first and second embodiments, the surface, that is, the exit surface of the front polarizing plate 22 is used as the display surface. In the present invention, the exit light from the liquid crystal cell 1 is enlarged and projected. The invention can also be applied to a so-called projection type liquid crystal display device having projection means.

That is, FIG. 6 is a schematic configuration diagram of a liquid crystal display device showing an embodiment in which the present invention is applied to a projection type liquid crystal display device. In front of the liquid crystal display unit A having the same configuration as the liquid crystal display device of the second embodiment, a projection lens system 51 for enlarging light emitted from the liquid crystal display unit A and projecting it on a projection surface such as a screen 50 is provided. Things.

In the liquid crystal display device of this embodiment, since the light emitted from the liquid crystal display section A is enlarged and projected by the projection lens system 51, the intensity of the light emitted from the liquid crystal display section A is reduced by the intensity of the luminous flux. Although it is attenuated with the enlargement, the liquid crystal display section A has the same configuration as that of the liquid crystal display device of the first or second embodiment described above. Since the intensity of the colored light emitted to the light source is sufficiently high, even if the light intensity is attenuated due to the expansion of the luminous flux, a clear enlarged color image with high luminance and good color purity can be displayed on a projection surface such as the screen 50. it can.

When the present invention is applied to the above-mentioned projection type liquid crystal display device, the liquid crystal display portion A
May have the same configuration as the liquid crystal display devices of the above-described third to fifth embodiments. In particular, the liquid crystal display portion A is made of a light-colored liquid crystal display like the liquid crystal display device of the first or second embodiment. Membrane 40
R, 40G, 40B or 41R, 41G, 41B on the back side of light source 30 and liquid crystal cell 1
With this configuration, the intensity of the colored light emitted to the front surface side of the liquid crystal cell 1 can be further increased, so that the emitted light from the liquid crystal cell 1 is enlarged and projected by the projection means. Even if the brightness is reduced, the brightness and the sharpness of the enlarged image projected and displayed on the projection surface such as the screen can be sufficiently increased.

The liquid crystal display section A in the liquid crystal display device according to the first to fifth embodiments and the liquid crystal display device according to the sixth embodiment includes a liquid crystal cell 1 having a TF as a switching element.
Although the liquid crystal cell 1 is of an active matrix type using T5, the liquid crystal cell 1 may be of an active matrix type using a MIM type two-terminal element as a switching element or a simple matrix type.

Further, the liquid crystal cell 1 is not limited to the TN type, but may be a guest cell using a liquid crystal to which a dichroic dye is added.
The liquid crystal cell 1 may be of a host type, in which case it is not necessary to dispose the polarizing plates 21 and 22 on the front and back sides of the liquid crystal cell 1.

The light source 30 disposed behind the liquid crystal cell 1 is not limited to the side lamp type used in each of the above embodiments. For example, a plurality of straight tube fluorescent lamps or the like may be disposed at appropriate intervals. May be so-called direct light sources arranged in parallel with each other.

[0062]

According to the present invention, a liquid crystal display device includes a liquid crystal cell, a light source disposed behind the liquid crystal cell, and a plurality of light-colored films corresponding to respective pixels of the liquid crystal cell. Since the light-colored films of the respective colors are each composed of a complex of a color filter of a predetermined color and a fluorescent substance of a similar color, a clear color image with high luminance and good color purity is displayed. can do.

In the liquid crystal display device according to the present invention, the light-colored film of each color may be formed by mixing a fluorescent substance in a color filter, or by laminating a color filter and a fluorescent film made of a fluorescent substance. However, if the latter light-colored film is used, and the light-colored film is arranged with the phosphor film facing the light source, colored light having higher intensity and color purity is incident on the liquid crystal cell. As a result, a clear color image with higher luminance and good color purity can be displayed.

In the liquid crystal display of the present invention,
The light-colored film of each color may be disposed between a light source and a liquid crystal cell, or may be provided on the inner surface of one of a pair of substrates of the liquid crystal cell, or may be provided on the surface of the liquid crystal cell. Although the most preferable location of the light-colored film is between the light source and the liquid crystal cell, if the light-colored film is disposed between the light source and the liquid crystal cell, Since light first enters the light-colored film, the light from the light source is most efficiently received by the fluorescent substance of the light-colored film to generate stronger colored fluorescence, and the intensity of the colored light emitted from the light-colored film is further increased. By increasing the height, the intensity of the colored light emitted to the surface side of the liquid crystal cell can be further increased.

Further, the present invention can be applied to a so-called projection type liquid crystal display device having a projection means for enlarging and projecting the light emitted from the liquid crystal cell. If the light colored film is disposed between the light source and the liquid crystal cell as described above, the intensity of the colored light emitted to the surface side of the liquid crystal cell can be further increased. Even if the brightness is reduced due to the projection by the projection means, the brightness and the sharpness of the enlarged image projected and displayed on the projection surface such as a screen can be sufficiently increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a part of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a part of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a part of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a part of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a part of a liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a liquid crystal display device showing an embodiment in which the present invention is applied to a projection type liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal cell 21, 22 ... Polarizer 30 ... Light source 40R ... Light-colored film (red) which mixed fluorescent substance with a color filter 40G ... Light-colored film (green) mixed with fluorescent substance into a color filter 40B ... Color filter Light-colored film (blue) 41R: light-colored film (red) formed by laminating a color filter and a phosphor film 41G: light-colored film (green) 41B: light-colored film formed by laminating a color filter and a phosphor film ... Light-colored films (blue) formed by laminating a color filter and a phosphor film 42R, 42G, 42B... Color filters 43R, 43G, 43B.

Claims (5)

[Claims] 1. A liquid crystal display device for displaying a color image, comprising: a liquid crystal cell; a light source disposed behind the liquid crystal cell;
A light-coloring film of a plurality of colors corresponding to each pixel of the liquid crystal cell, wherein the light-coloring films of the respective colors are each composed of a complex of a color filter of a predetermined color and a fluorescent substance of a similar color to the color filter. A liquid crystal display device comprising: 2. The liquid crystal display device according to claim 1, wherein the light colored films of the respective colors are disposed between the light source and a liquid crystal cell. 3. The liquid crystal display device according to claim 2, further comprising projection means for enlarging and projecting the light emitted from said liquid crystal cell. 4. The liquid crystal display device according to claim 1, wherein the light colored film of each color is provided on an inner surface of one of a pair of substrates of the liquid crystal cell. 5. The liquid crystal display device according to claim 1, wherein the light colored films of the respective colors are arranged on a surface of the liquid crystal cell.