JPH11142835A - Color filter substrate with micro lens - Google Patents

Abstract

(57) [Summary] [Problem] To provide a color filter substrate with a microlens having high light use efficiency, thereby improving the display quality of an image display device using the color filter substrate with a microlens. In a color filter substrate with a micro lens, at least a color filter layer including a plurality of rectangular colored pixels, a micro lens layer, and a black matrix layer are sequentially laminated on a transparent substrate. A color filter substrate with microlenses, wherein the microlenses constituting the layer are square or substantially square in plan view.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter substrate with microlenses constituting a liquid crystal display panel used for an image display device, and more particularly to a color liquid crystal display panel used for a projection type image display device such as a liquid crystal projector. And a color filter substrate with microlenses.

[0002]

2. Description of the Related Art Projection-type image display devices such as projection televisions project a display image on a screen in an enlarged manner, and those using a liquid crystal display panel are becoming mainstream. A liquid crystal display panel is a liquid crystal display panel in which liquid crystal is sandwiched and sealed between a pair of opposing substrates having electrodes in a predetermined pattern. The image display is performed by controlling the transmission and non-transmission of the irradiated light for each pixel.

Usually, one substrate constituting a liquid crystal display panel has a color filter layer 13 in which a plurality of colored pixels 14 are formed on a transparent substrate 15, as shown in FIG. 7, in order to obtain a colored image. It is a substrate (color filter substrate). The colored pixels 14 are formed of a resin in which a pigment is dispersed, an optical interference film in which a plurality of inorganic materials are stacked, or the like, for example, R (red), G (green), and B (blue).
The light is emitted from a light source such as a lamp, and the light emitted from a light source such as a lamp is given a color according to the pixel when passing through the colored pixel 14 of each color. Next, on the color filter substrate, in order to improve the contrast of the displayed image, a black matrix layer 17 in which a portion facing each colored pixel 14 is an opening 18 and other portions are light shielding portions 19 is formed.

In recent years, a projection type image display device has been required to have a large screen. Therefore, it is required to project an image displayed on a liquid crystal display panel at a high magnification. . Further, the image display device is also required to have a high definition image, and in order to project the liquid crystal display image with high definition at a high magnification, the number of pixels constituting the liquid crystal display panel is increased. It is necessary.

However, when the number of pixels of the liquid crystal display panel is increased, an opening 18 formed in the black matrix layer 17 is formed.
Must be increased, and accordingly, the proportion of the light shielding portion 19 other than the opening 18 increases. Further, when the number of the openings 18 is increased, the area of each of the openings 18 has to be reduced, so that the so-called aperture ratio is reduced. When the aperture ratio of the black matrix layer 17 decreases, the amount of light passing through the opening 18 decreases, so that the display image on the image display device becomes dark and the quality of the display image decreases.

Conventionally, the above-described black matrix layer
As means for preventing the deterioration of the quality of the displayed image due to the decrease in the aperture ratio of 17, a color filter substrate 11 with microlenses formed by forming microlenses 12 on colored pixels 14, as shown in FIG. Is what it is. That is, in the related art, light that has passed through the colored pixels 14 facing the light-shielding portion 19 of the black matrix layer 17 has been blocked by the light-shielding portion 19 of the black matrix layer 17. However, when the microlenses 12 are formed on the colored pixels 14, the microlenses 12 condense the light that has been blocked by the light-shielding portions 19 of the black matrix layer 17 and guide the light to the openings 18.
The amount of light passing through the opening 18 is increased, and the use efficiency of light is increased by the formation of the microlenses 12, so that the quality of a displayed image is improved.

The microlenses 12 are formed so as to face the respective colored pixels 14 and have substantially the same shape as the respective colored pixels 14 in a plan view with substantially no gap. That is, by making the microlenses 12 have substantially the same shape as the colored pixels 14 in plan view, the light condensing effect is enhanced, and the light passing through the colored pixels 14 is to be used to the maximum without waste. In order to increase the focal length of the micro lens 12, a transparent buffer layer is provided between the micro lens 12 and the black matrix layer 17.
It is common to form 16.

Here, the shape of each of the colored pixels 14 formed on the color filter substrate 11 with microlenses and each of the openings 18 of the black matrix layer 17 facing each other is rectangular (rectangular) in plan view due to image display characteristics. In general, this tendency becomes more remarkable as the resolution of pixels is required to be higher.

For this reason, as shown in FIG. 6, the plane shape of the microlenses 12 is also formed in a rectangular (rectangular) shape in accordance with the plane shape of the colored pixels 14. FIG. 6 shows a plurality of colored pixels constituting a color filter layer 13 of a conventional color filter substrate 11 with microlenses.
One colored pixel in 14 (for example, R (red) colored pixel)
It is the top view which expanded the part.

[0010]

As described above, the conventional microlenses 12 formed on the color filter substrate 11 with microlenses have a rectangular (rectangular) shape in plan view as shown in FIG. Is what it is.

In the microlens 12 having a rectangular shape (rectangular shape) in plan view, each side surface is naturally curved to provide a lens effect. However, as shown in FIG. 5A, which is a cross-sectional view of the microlens 12 along line XX ′ in FIG. 6, and FIG. 5B, which is a cross-sectional view of the microlens 12 along line YY ′. The curvature (R ₁ ) on the long side of the microlens 12 and the curvature (R ₂ ) on the short side are greatly different. Therefore, it is assumed that the focal length f ₂ of the focal length f ₁ and short side of the long side is different, the collected light is not condensing on one point by the microlens 12, and those that result in the so-called astigmatism.

The light that has passed through the colored pixels 14 is rectangular (rectangular).
As shown in FIG. 4, which schematically shows a state where light is condensed by a microlens 12 having a shape, a focus B condensed at a position of a focal length f ₁ on the long side is located at an opening 18 of a black matrix layer 17. Even if it does, the focal point A condensed at the position of the focal length f ₂ on the short side is in front of the opening 18 of the black matrix layer 17. Thus, a rectangular (rectangular) micro lens
In FIG. 12, there are a plurality of focal points, and at each focal point, spot light (condensed at one point) is not formed but slit light (condensed in a rectangular shape).

Therefore, no matter how the buffer layer 16 is formed between the microlens 12 and the black matrix layer 17, the light collected by the microlens 12 does not converge at one point. A light beam that is out of focus on the surface (for example, light collected at the focus A in FIG. 4) is kicked without being incident on the opening 18 of the black matrix layer 17 (obstructed by the light shielding portion 19). Is what you do.

That is, in the conventional color filter substrate having the rectangular (rectangular) microlenses 12 (the color filter substrate 11 with microlenses), the light use efficiency cannot be increased, and the required high efficiency is required. There is a problem that it is impossible to display a high-quality image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a color filter substrate with microlenses having high light use efficiency. The display quality of the image display device is improved.

[0016]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have made intensive studies, and as a result, have noticed that the planar shape of the microlens is square or substantially square. It was done. That is, claim 1 is a color filter substrate with a micro lens in which at least a color filter layer formed of a plurality of rectangular colored pixels, a micro lens layer, and a black matrix layer are sequentially formed on a transparent substrate. The microlens forming the microlens layer is a color filter substrate with a microlens, wherein the microlens has a square shape or a substantially square shape in plan view.

As described above, since the conventional microlens has a rectangular (rectangular) shape, the curvature (R ₁ ) on the long side and the curvature (R ₂ ) on the short side are different from each other. Unlike the focal length f ₂ of the focal length f ₁ and short side,
It was not focused at one point. However, the microlens according to the present invention is a square or a substantially square, and the lengths of the four sides are substantially equal, the curvature of the curved surface formed on each side can be equal, and the focal length on each side is also Can be equal. That is, light condensed by the microlens according to the present invention can be condensed at one point. By adjusting the thickness of the buffer layer and the distance between the microlens and the black matrix layer, light that has passed through the microlens can be guided to the opening of the black matrix layer without being kicked. Usage efficiency can be increased.

Here, as described above, the shape of the colored pixel facing the microlens is rectangular (rectangular) in plan view.
It is in a shape. For this reason, when the shape of the microlens is square or substantially square, the planar shapes of the microlens and the colored pixel are different, and it can be said that it is impossible to cover one colored pixel region with one microlens. The invention according to claim 2 solves this. That is, the invention according to claim 2 is a color filter substrate with microlenses, wherein a plurality of microlenses are formed for each colored pixel forming the color filter layer. Is covered by a plurality of microlenses.

Here, when a plurality of microlenses are formed for each colored pixel, arranging the microlenses arranged in each colored pixel region without gaps increases the filling ratio of the microlenses for each colored pixel. This is advantageous in condensing light at one point. That is, in the third aspect of the present invention, there is provided a color filter substrate with microlenses, wherein a plurality of microlenses formed for each colored pixel are formed in a state of being substantially adhered.

Next, it is desirable that the size of the microlens formed be as large as possible. The reason will be described below.

In forming a microlens, a heat flow type microlens forming method is generally used. That is, a material (for example, a transparent photosensitive resin) to be a microlens is applied on the substrate.
Then, after pattern exposure to the photosensitive resin through a pattern exposure mask having a predetermined pattern, development is performed,
A transparent resin layer is formed at a portion where a microlens is to be formed. Next, a heat treatment is performed on the substrate to melt the surface of the transparent resin layer, thereby forming a microlens having a curved surface. When microlenses are formed by the heat flow method, if there is no gap between individual microlenses, adjacent microlenses are welded during heat treatment, and a desired curved surface cannot be formed. For this reason, it is necessary to keep the distance between adjacent microlenses to some extent,
It is necessary to provide a gap between the microlenses.

Here, in the present invention, a plurality of microlenses are formed for each colored pixel, but the size of the microlenses is reduced and the number of microlenses formed for each colored pixel is increased. In this case, the ratio of the space between the microlenses increases, and the filling ratio of the microlenses to the colored pixels (the ratio of the microlens covering the colored pixel area) decreases, and the intensity of the light condensed by the microlenses decreases. Will be lowered. That is, by enlarging the square microlenses as much as possible and covering the colored pixels with a small number of microlenses, the ratio of the gaps between the microlenses can be reduced, the filling rate of the microlenses is increased, and the light intensity of the condensed light is increased. Can be raised.

The present inventors have made intensive studies to cover the colored pixels with a square-shaped microlens as large as possible and to increase the intensity of light to be condensed. As a result, the colored pixels are rectangular (rectangular). It is proposed that the shape of the colored pixel be as follows. That is, the invention according to claim 4 satisfies By = k × Bx (k is an integer of 2 or more) when the length of the short side of the rectangular colored pixel is Bx and the length of the long side is By. This is a color filter substrate with a microlens characterized by having a rectangular shape.

As described above, by setting the length of the long side to be an integer multiple of the length of the short side, the shape of the colored pixel can be reduced.
The colored pixels can be covered with the minimum number of microlenses. For example, if a colored pixel whose long side is twice as long as the short side is used, a square microlens whose one side is the length of the short side of the colored pixel is formed in the longitudinal direction of the colored pixel. The colored pixels can be covered with the microlenses by arranging two of them.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a color filter substrate with microlenses according to an embodiment of the present invention.

FIG. 3 is a plan view of the color filter substrate 1 with microlenses according to the present embodiment as viewed from the black matrix layer 7 side. A portion K in FIG. 3 exposes a part of the color filter layer 3 formed on the transparent substrate 5 and includes R (red), G (green), and B (blue) colored pixels. No. 4 is formed by a conventionally known forming means such as a pigment dispersion method. As shown in the portion K in FIG. 3, in the color filter substrate 1 with microlenses of the present embodiment, a large number of rectangular colored pixels 4 are arranged so as to have almost no gap, and
The colored pixels 4 are arranged at equal pitches.

In this embodiment, as shown in FIG.
The pitch dimension for arranging the colored pixels 4 is Dx in the X direction,
Assuming that the Y direction is Dy, Dy = 2 × Dx. The R (red), G (green), and B (blue) colored pixels 4 have the same size, the short side length is Bx, and the long side length is By.
Then, By = 2 × Bx. Further, the colored pixel 4
And the dimensions of the colored pixels 4 are set to be substantially the same. That is, Bx = Dx and By = Dy.

Next, part L in FIG. 3 shows a part of the microlens layer formed on the colored pixel 4 so as to be opposed to the colored pixel 4. As shown in a portion L in FIG. 3, in the color filter substrate with microlenses 1 of this embodiment, two square microlenses 2 are formed for each colored pixel 4 in the longitudinal direction of the colored pixel 4. .

Further, the length Mx of one side of the square microlens 2 formed in the present embodiment is, as shown in FIG. The distance from the edge to the microlens 2 is S, and Mx
= (Bx-2S).

In this embodiment, as described above, B
y = 2 × Bx, and two square microlenses 2 are formed in the longitudinal direction of the rectangular colored pixel 4. The vertical and horizontal dimensions of the colored pixel 4 are By = K × Bx (K is 2 or more). ), K colored microlenses 2 may be formed in the longitudinal direction of the colored pixel 4. Even in that case, the length M of one side of the square microlens 2 is M
x is set as Mx = (Bx−2S).

However, as described above, if K is too large, the number of arranged microlenses 2 increases, and the proportion of the distance S (so-called dead space) from the edge of the colored pixel to the microlens increases. For this reason, the filling rate of the microlenses with respect to the colored pixels decreases, so that K is desirably about 2 to 3.

In the color filter substrate 1 with microlenses according to the present embodiment, as shown in FIG. 2, which is a drawing showing a cross section taken along the line ZZ 'in FIG. After forming the layer 6, a black matrix layer 7 is formed.

The color filter substrate 1 with microlenses according to the present embodiment is manufactured by the following known manufacturing means. That is, first, a colored pixel 4 of R (red) color, G (green) color, B (blue) color, or the like is formed on a transparent substrate 5 such as glass by a pigment dispersion method, an inorganic multilayer film deposition method, or the like. It was formed in the above-described arrangement pattern.

Next, after the colored pixels 4 are formed, the transparent substrate 5
A transparent lens material (photosensitive resin) was applied (coated) on the top. Next, a pattern exposure mask having a square pattern was overlaid on the lens material to perform pattern exposure, followed by development processing. As a result, a lens base material having a square shape in plan view was obtained.

Next, a heat treatment was performed on the transparent substrate 5. As a result, the lens base material is melted, and the surface of the lens base material becomes a curved convex surface. Next, the lens base material was cured while the surface of the lens base material was kept convex. As a result, a desired square microlens 2 in a plan view was obtained.

Next, the focal length of the microlens 2 is considered on the microlens 2 and, for example, the microlens 2
The transparent buffer layer 6 having a layer thickness corresponding to the focal length of was formed of a transparent resin or the like. Next, a black matrix layer 7 is formed on the buffer layer 6. As a means for forming the black matrix layer 7, after depositing a metal chromium film on the buffer layer 6, an opening 8 is formed by a photo-etching method, or after applying a black resin on the buffer layer 6, pattern exposure, For example, there is a method of performing development.

Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above description and drawings, and various modifications are made based on the spirit of the present invention. Needless to say, it does not matter.

[0038]

As described above, in the color filter substrate with microlenses of the present invention, square or substantially square microlenses are formed on a color filter layer having rectangular colored pixels. . Thereby, in the microlens according to the present invention, the difference in the curvature of the lens surface can be made smaller than that of a conventionally formed rectangular microlens.

Therefore, it is possible to prevent a phenomenon that the light passing through the colored pixels and the microlenses is kicked (shielded) by the light shielding portion without passing through the opening of the black matrix layer.

Further, in the present invention, a plurality of microlenses having the above-mentioned shape are arranged in each colored pixel so that there is almost no gap, so that the filling rate for the colored pixels can be increased.

That is, by using the color filter substrate with a microlens of the present invention, the light utilization efficiency of the light passing through the colored pixels can be increased, and an image display device using the color filter substrate with a microlens of the present invention can be obtained. In, a bright display image can be obtained.

[0042]

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing a main part of an embodiment of a color filter substrate with microlenses of the present invention.

FIG. 2 is an explanatory sectional view showing one embodiment of a color filter substrate with microlenses of the present invention.

FIG. 3 is an explanatory plan view showing one embodiment of a color filter substrate with microlenses of the present invention.

FIG. 4 is an explanatory diagram showing an example of a difference in focus of a micro lens formed on a conventional color filter substrate with a micro lens.

FIGS. 5A and 5B are explanatory diagrams showing an example of a focal length of a microlens formed on a conventional color filter substrate with microlenses. FIGS.

FIG. 6 is an enlarged explanatory view showing a main part of an example of a conventional color filter substrate with microlenses.

FIG. 7 is an explanatory view showing an example of a conventional color filter substrate with microlenses.

[Explanation of symbols]

 1,11 color filter substrate 2,12 micro lens 3,13 cutter filter layer 4,14 colored pixel 5,15 transparent substrate 6,16 buffer layer 7,17 black matrix layer 8,18 opening 9,19 light shielding part

Claims (4)

[Claims] 1. A color filter substrate with microlenses, wherein at least a color filter layer comprising a plurality of rectangular colored pixels, a microlens layer, and a black matrix layer are sequentially formed on a transparent substrate. A color filter substrate with microlenses, wherein the microlenses constituting the lens layer are square or substantially square in plan view. 2. The color filter substrate with microlenses according to claim 1, wherein a plurality of microlenses are formed for each colored pixel constituting the color filter layer. 3. The color filter substrate with microlenses according to claim 2, wherein a plurality of microlenses formed for each of the colored pixels are formed in a substantially close contact state. 4. A rectangular pixel which satisfies By = k × Bx (k is an integer of 2 or more), where Bx is the length of the short side and By is the length of the long side of the rectangular colored pixel. The color filter substrate with a micro lens according to claim 1, wherein: