JPH11202118A - Color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light transmissivity without lowering the color purity. SOLUTION: White light 10 which is made incident on the color filter has its wavelength converted by color converting layers 2G, 2R, and 2B and is emitted as light (which can be transmitted through filter layers 3G, 3R, and 3B) effective to the filter layers 3G, 3R, and 3B. The color conversion layers 2G, 2R, and 2B transmit light which does not have its wavelength converted as it is. Thus, the light in the wavelength range which is not transmitted through a conventional color filter can effectively be utilized to improve the light transmissivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art For example, many image pickup apparatuses for photographing images and display apparatuses for displaying images have been developed which are compatible with colorization. Here, there is a color filter as one of means for realizing colorization.

Conventional color filters include, for example, a colored pattern for color display (for example, R (red), G (green), B
(Colored pattern of (blue)). In such a color filter, only light in a specific wavelength range is selectively transmitted, and light outside the specific wavelength range is absorbed.

[0004]

However, the color filters used in the prior art do not transmit light outside the specific wavelength range, and thus have a problem of low light transmittance. For example, in an RGB color filter, the G color filter portion absorbs the light in the wavelength ranges corresponding to the R and B colors of the incident white light and transmits the G color light. This means that 2/3 or more of the light is lost. Further, in order to increase the light transmittance, the wavelength range of the light to be transmitted must be expanded, but this causes a problem that the color purity of the transmitted light is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a color filter which can improve light transmittance without lowering color purity.

[0006]

A color filter according to the present invention is provided on a color conversion means for converting a part of incident light into light of a specific wavelength range, and on a light emission side of the color conversion means. And a filter means for transmitting only light in a specific wavelength range of the incident light.

In this color filter, a part of the incident light is converted into light in a specific wavelength range by the color conversion means. The filter unit transmits only light in a specific wavelength range including the light converted by the color conversion unit.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a sectional view showing a schematic configuration of a color filter according to a first embodiment of the present invention. This color filter is used as an RGB color filter, and includes a transparent glass substrate 1 on which white light 10 is incident from one surface and a light on the other surface of the glass substrate 1, that is, the light on the glass substrate 1. Color conversion layers 2G, 2R, 2B stacked on the emission side of
Filter layer 3 laminated on the emission side of G, 2R, 2B light
G, 3R and 3B. The color filter includes a color conversion layer 2 laminated on one side of the glass substrate 1.
A flattening layer 4 for flattening the G, 2R, 2B and the filter layers 3G, 3R, 3B is provided. Here, the filter layers 3G, 3R, 3B correspond to "filter means" in the present invention. Further, the color conversion layers 2G, 2R,
2B corresponds to "color conversion means" in the present invention.

The filter layers 3G, 3R, and 3B selectively transmit only light in a specific wavelength range among the incident light. That is, the filter layer 3G selectively transmits light in the G wavelength range.
R selectively transmits light in the wavelength range of R color. The filter layer 3B selectively transmits light in the B color wavelength range. These filter layers 3G, 3
R and 3B are layers formed by forming a dye substrate on one side of the color conversion layers 2G, 2R and 2B, and then dyeing the dye substrate with a dye for each color to form a color. The filter layers 3G, 3R, and 3B are made of a colored resin in which a dye or pigment for each color is dispersed in a resin.
It may be formed by laminating on one surface of 2R, 2B.

The color conversion layers 2G, 2R, and 2B convert a part of the incident light into light of a specific wavelength range, and
The light is emitted to 3R and 3B. That is, the color conversion layer 2G is, for example, a wavelength region (for example, about 360 to 450 nm) of the incident light from the near ultraviolet to the vicinity of the B color.
, And converts the absorbed light into light in a wavelength range near G color (for example, about 450 to 550 nm) and emits the light to the filter layer 3G. Also,
The color conversion layer 2R, for example, absorbs light in the wavelength range from near ultraviolet to near G color (for example, about 360 to 550 nm) out of the incident light, and converts the absorbed light into the wavelength range near R color (for example). For example, the light is converted into light having a wavelength of about 600 to 650 nm and emitted to the filter layer 3R. The color conversion layer 2B is, for example, a wavelength region near the near ultraviolet region (for example, about 360 to 420 nm) of the incident light.
And converts the absorbed light into light in the wavelength range near B color (for example, about 420 to 480 nm) and emits the light to the filter layer 3B. As described above, the color conversion layers 2G, 2R, and 2B convert a part of the incident light into light effective for the filter layers 3G, 3R, and 3B (light that can be transmitted through the filter layers 3G, 3R, and 3B). And is emitted.

The color conversion layers 2G, 2R, and 2B are formed by dispersing a substance having the above-described color conversion properties in a resin on the glass substrate 1 in a predetermined pattern. As a pattern forming method, for example, a photolithography method or the like can be used. The color conversion layer 2
G, 2R, and 2B may be formed by, for example, directly depositing the substance having the above-described color conversion property on the glass substrate 1. Further, the color conversion layers 2G, 2R, 2B
For example, a material obtained by dissolving a substance having the above-described color conversion property in a liquid may be formed by stacking on the glass substrate 1.

Next, with reference to FIGS. 2 and 3, specific examples of substances used for the color conversion layers 2G, 2R, 2B will be described.

For the color conversion layer 2G, for example, Coumarin 337, 523 represented by the following formula can be used as a main material.

[0015]

Embedded image

FIG. 2 shows Coumarin 337,5 represented by this equation.
23 is a diagram showing the light absorption characteristics of 23 light, in which the horizontal axis represents wavelength and the vertical axis represents light absorption. As shown in this figure, the color conversion layer 2G mainly composed of Coumarin 337, 523 absorbs light in a wavelength region centered on 443 nm and converts the absorbed light into light in a wavelength region of 500 to 560 nm. It has the property of being able to. Also,
The color conversion layer 2G transmits light in the wavelength range corresponding to the G color as it is. Therefore, the color conversion layer 2G can emit light in the wavelength ranges corresponding to the B color and the G color as light effective for the filter layer 3G (light that can be transmitted through the filter layer 3G).

For the color conversion layer 2R, for example, DCM represented by the following formula can be used as a main material. Note that D
The official name of CM is [2- [2- [4- (Dimethylamino) phenyl] e
thenyl] -6-methyl-4H-pyran-4-ylidene] propanedinitri
le.

[0018]

Embedded image

FIG. 3 is a diagram showing the light absorption characteristics of the DCM represented by this equation. In the figure, the horizontal axis represents the wavelength, and the vertical axis represents the light absorption. As shown in this figure, the color conversion layer 2R mainly composed of DCM is 469n.
It has a characteristic that it absorbs light in a wavelength region centered on m and can convert the absorbed light into light in a wavelength region of 571 to 727 nm. In addition, the color conversion layer 2R
Light in the wavelength range corresponding to the color is transmitted as it is. Therefore,
The color conversion layer 2R converts the light in the wavelength range corresponding to the B color and the R color and the light in a partial wavelength range corresponding to the G color into the filter layer 3R.
Can be emitted as effective light (light that can be transmitted through the filter layer 3R).

For the color conversion layer 2B, for example, Coumarin 102 represented by the following formula can be used as a main material.

[0021]

Embedded image

The color conversion layer 2B mainly composed of Coumarin 102 represented by this formula absorbs light in a wavelength region centered at 390 nm and absorbs the absorbed light in a wavelength range of 450 to 530 nm.
It has the characteristic that it can be converted to light in the wavelength range of m. Therefore, the color conversion layer 2B can emit light in the wavelength region corresponding to the near ultraviolet region and the B color as light effective for the filter layer 3R (light that can be transmitted through the filter layer 3R).

Next, the operation of the color filter having the above configuration will be described.

The white light 10 incident on the color filter is
First, the color conversion layers 2G, 2R, and 2B undergo a wavelength conversion action. The color conversion layer 2G absorbs, for example, the light in the wavelength range from the near ultraviolet to the B color in the incident white light 10, and converts the absorbed light into light in the wavelength range in the G color range to filter. The light is emitted to the layer 3G. The color conversion layer 2
R absorbs, for example, light in the wavelength range from near ultraviolet to G color in the incident white light 10, converts the absorbed light into light in the wavelength range near R color, and outputs the light to the filter layer 3R. Emit. The color conversion layer 2B, for example, absorbs light in the wavelength region near the near ultraviolet region of the incident white light 10 and converts the absorbed light into light in the wavelength region near the B color to form a filter. The light is emitted to the layer 3B. As described above, the color conversion layers 2G, 2R, and 2B use the part of the incident white light 10 as light effective for the filter layers 3G, 3R, and 3B (light that can be transmitted through the filter layers 3G, 3R, and 3B). And output. In the color conversion layers 2G, 2R, and 2B, the light in the wavelength range that has not been subjected to the wavelength conversion action is transmitted to the color conversion layer 2G.
G, 2R and 2B are transmitted as they are.

Next, the light emitted from the color conversion layers 2G, 2R, 2B enters the filter layers 3G, 3R, 3B. The filter layers 3G, 3R, and 3B selectively transmit only light in a specific wavelength range among the incident light. That is, the filter layer 3G selectively transmits light in the G wavelength range, and the filter layer 3R selectively transmits light in the R wavelength range. Further, the filter layer 3B selectively transmits light in the B color wavelength range.

As described above, according to the color filter of the present embodiment, a part of the incident light in the color conversion layers 2G, 2R, and 2B is filtered by the filter layers 3G, 3R, and 3B.
Since the light is converted into light effective for B and emitted, light in a wavelength range not transmitted by the conventional color filter can be effectively used, and light transmittance can be improved. . In addition, since light of an unnecessary wavelength transmitted through the color conversion layers 2G, 2R, and 2B is absorbed by the filter layers 3G, 3R, and 3B, the color purity does not decrease. Thus, according to the color filter according to the present embodiment, it is possible to improve the light transmittance without lowering the color purity.

[Second Embodiment] Next, a second embodiment of the present invention will be described.
An embodiment will be described. In the first embodiment, a description has been given of the color filter alone.
In this embodiment mode, a liquid crystal display device to which the color filter of the present invention is applied will be described. In the following,
In the liquid crystal display device, a portion using a color filter, that is, a liquid crystal panel used in the liquid crystal display device will be described.

FIG. 4 is a sectional view showing a schematic configuration of the liquid crystal panel in the present embodiment. The liquid crystal panel shown in this figure is used for a reflection type liquid crystal display device. Note that a polarizing plate is usually required in a liquid crystal panel, but is not shown here.

This liquid crystal panel has a reflection plate 70 on one surface.
, A counter substrate 40 facing the pixel substrate 60, and a liquid crystal layer 50 made of a liquid crystal material sandwiched between the pixel substrate 60 and the counter substrate 40.

The pixel substrate 60 is composed of a glass substrate 61 and B-color light and R-color light that are regularly (periodically) arranged on one side of the glass substrate 61 (the side on which the reflection plate 70 is not attached).
It has pixel electrodes 62B, 62R, and 62G for color light and G color light. The pixel electrodes 62B, 62R, and 62G are composed of transparent electrodes, and the protective layer 6 has a planarized surface.
3 covered.

The opposing substrate 40 includes a glass substrate 41 and a color conversion layer 42 G attached to one side of the glass substrate 41.
42R, 42B, and filter layers 43G, 43R, 43B attached to the color conversion layers 42G, 42R, 42B. The color conversion layers 42G, 42R, 42B and the filter layers 43G, 43R, 43B are flattened by the flattening layer 44. Further, the counter substrate 40 includes a counter electrode 45 attached to the surface of the flattening layer 44. In the counter substrate 40, the portion excluding the counter electrode 45 corresponds to the color filter in the first embodiment, and the color conversion layer 4 which is a characteristic portion thereof is used.
2G, 42R, 42B and filter layers 43G, 43
Since the configurations of R and 43B are the same, detailed description is omitted here.

The liquid crystal layer 50 includes pixel electrodes 62B, 62R,
Between 62G and the counter electrode 45, the liquid crystal molecule orientation changes according to the image signal voltage. Thereby, the polarization direction of the light passing through the liquid crystal layer 50 is controlled.

Next, the operation of the liquid crystal panel having the above configuration will be described.

In this liquid crystal panel, first, white light from a light source (not shown) is incident on the surface of the counter substrate 40. The white light incident on the counter substrate 40 is transmitted to the color conversion layers 42G and 42G.
R and 42B undergo a wavelength conversion operation. Regarding the conversion action by the color conversion layers 42G, 42R, 42B,
The color conversion layers 2G, 2R, 2 in the first embodiment.
The operation is similar to that of B, and a part of the incident white light is converted into light effective for the filter layers 43G, 43R, and 43B and emitted. Further, the color conversion layers 42G, 42R, 42
In B, the light in the wavelength range that has not been subjected to the wavelength conversion operation passes through the color conversion layers 42G, 42R, and 42B as it is. The light emitted from the color conversion layers 42G, 42R, 42B is
The light enters the filter layers 43G, 43R, and 43B. The filter layers 43G, 43R, and 43B selectively transmit only light of G, R, and B colors, respectively, of the incident light.

The G, R, and B color lights emitted from the opposite substrate 40 enter the pixel substrate 60 via the liquid crystal layer 50. Each color light incident on the pixel substrate 60 is reflected on the reflection plate 70, and reaches the opposite substrate 40 again via the pixel substrate 60 and the liquid crystal layer 50. Here, each color light of G, R, and B is applied to the liquid crystal layer 5.
0, the pixel electrode 62B of the pixel substrate 60,
In accordance with the color image signal for each color applied to 62R and 62G, the liquid crystal molecular orientation of the liquid crystal layer 50 in the area corresponding to each pixel changes, and B, R, and G incident on the liquid crystal layer 50 in each area. Are subjected to spatial modulation selectively. Each color light that has been subjected to the spatial modulation passes through a polarizing plate (not shown) according to the degree of the modulation, is emitted from the liquid crystal panel, and is used for image display.

As described above, according to the liquid crystal panel of the present embodiment, the color conversion layers 42G, 42R, 42B and the filter layers 43G,
By the action of 43R and 43B, each color light required for color display can be extracted at a high transmittance without lowering the color purity, so that a high-luminance image display can be realized using this light.

The other functions and effects provided by the color conversion layers 42G, 42R, 42B and the filter layers 43G, 43R, 43B are the same as in the first embodiment.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and can be variously modified. For example, in the above embodiment, the basic colors for color display have been described as the three primary colors of R, G, and B. However, for example, three colors of cyan (C), magenta (M), and yellow (Y) are used as the basic colors. May be adopted.

The color filter of the present invention can be used not only in a reflection type liquid crystal display device but also in a projection type liquid crystal display device such as a liquid crystal projector.
Furthermore, the present invention can be used not only in a liquid crystal display device but also in various types of devices that support colorization using a color filter, such as an imaging device using a charge coupled device (CCD).

[0040]

As described above, claim 1 or claim 2
According to the color filter described in (1), since a part of the incident light is wavelength-converted by the color conversion means into light in a specific wavelength range that can be transmitted through the filter means, the light can be converted without lowering the color purity. There is an effect that the transmittance can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a color filter according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram for explaining characteristics of a color conversion layer in FIG.

FIG. 3 is another characteristic diagram for explaining characteristics of the color conversion layer in FIG.

FIG. 4 is a sectional view showing a main part of a liquid crystal device according to a second embodiment of the present invention.

[Explanation of symbols]

1,41: glass substrate, 2G, 2R, 2B, 42G, 4
2R, 42B ... color conversion layer, 3G, 3R, 3B, 43G,
43R, 43B: filter layer, 4: flattening layer, 40: counter substrate, 50: liquid crystal layer, 60: pixel substrate, 70: reflector

Claims (2)

[Claims] 1. A color conversion means for converting a part of incident light into light of a specific wavelength range, and a light of a specific wavelength range among the incident lights, the color conversion means being provided on a light emission side of the color conversion means. A filter means for transmitting only light. 2. The filter means comprises: red, green,
It has a plurality of filters for a basic color that transmits only light in a wavelength range centered on blue, and the color conversion means is provided on the light incident side of the red filter, and near-green to near green. A color conversion unit for red that converts light in a wavelength range to light in a wavelength range near red,
A green color conversion unit that is provided on the light incident side of the green filter and converts light in the near-ultraviolet to near-blue wavelength region into light in the near-green wavelength region, and light of the blue filter 2. The color filter according to claim 1, further comprising: a blue color conversion unit provided on the incident side and configured to convert light in the near ultraviolet region into light in a wavelength region near blue.