JP2005122101A - Electrooptic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new electrooptic device in which visibility can be greatly improved by making effective use of light shielding films covering the non-apertures of pixels and the excellent visibility like that of paper printed matter etc., can be assured. <P>SOLUTION: The electrooptic device equipped with a display panel where the pixels having apertures and the non-apertures are arrayed is equipped with the light shielding films on the light exit side of the display panel so as to cover the non-apertures, wherein the light shielding films are formed of a light diffusive material. As a result, the surface of the display panel can be provided with texture like that of paper and the excellent visibility like that of the paper printed matter etc., can be exhibited. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electro-optical device such as an LCD (liquid crystal display), an OLED (organic electroluminescence display), an EPD (electrophoretic display), and a PDP (plasma display).

Such an electro-optical device has characteristics such as thin and light weight, low power consumption, and easy large screen. Therefore, the electro-optical device is rapidly used in various fields as an electronic display device replacing the conventional CRT (cathode-ray tube). The demand is growing.
In this electro-optical device, for example, a large number of pixels filled with a light control material such as liquid crystal or gas are arranged in a plane, and the light control material of each pixel is electrically driven to transmit the amount of light transmitted therethrough. By controlling, a desired display of images, characters, and the like is performed.

  In a conventional electro-optical device having such a configuration, an opening that is a part where light is controlled, that is, a part that contributes to direct display, and a part that does not control light, that is, a part that does not contribute to direct display. In general, an opening exists for each pixel. For example, in an LCD (liquid crystal display) or the like, the central portion of each pixel functions as an opening for controlling light, and a portion where an element such as a TFT (thin film transistor) is disposed or a boundary portion between pixels is provided. It is a non-opening where light is not controlled.

In the conventional LCD having such a configuration, the non-opening portion is black in order to protect the elements such as TFTs from light and to improve the blackness and display with high contrast. Generally, it is covered with a black light-shielding film made of a metal thin film, a black pigment, or the like, called a matrix (BM).
By the way, in a liquid crystal display used in a recent personal computer (PC) or the like, the background color of the liquid crystal display has become the mainstream instead of the conventional black color tone. If a black light-shielding film such as a black matrix is used as a light-shielding film for covering the opening, the black light-shielding film is conspicuous in the form of a lattice on the white background, and the visibility deteriorates. is there.

Therefore, conventionally, as shown in, for example, Patent Documents 1 and 2 below, in the case of a liquid crystal display with a white background color, a conventional black color is used as a light shielding film provided between the pixels (non-openings). There has been proposed a method for improving the visibility of a liquid crystal display with a white background color by using a white one instead of the one.
JP-A-11-271755 JP 2002-229046 A

However, the method of using a white type instead of black as the light shielding film in this way makes the light shielding film itself inconspicuous. Since it is disposed inside a filter or the like, the visibility of the display cannot be improved using the light shielding film.
On the other hand, in an electronic display device such as an LCD as described above, the visibility has been improved year by year due to the higher definition of pixels and the improvement of manufacturing technology. However, images and characters are actually displayed on a paper medium. The present situation is that it has not yet reached an excellent visibility such as a printed paper on which is printed.

Therefore, the present invention has been devised to effectively solve such problems, and one of its main purposes is to greatly improve the visibility by utilizing a light shielding film covering the non-opening portion of the pixel. It is an object of the present invention to provide a novel electro-optical device that can be improved.
Another main object of the present invention is to provide a novel electro-optical device capable of ensuring excellent visibility such as printed paper.

[Invention 1] In order to solve the above problems, an electro-optical device according to Invention 1 comprises:
An electro-optical device including a display panel in which pixels having openings and non-openings are arranged, the light-shielding film being provided on the light output side of the display panel so as to cover the non-openings, and the light-shielding film It is characterized by being optimized according to the purpose of display.
As described above, the light-shielding film is provided on the light output side of the display panel, and the light-shielding film is optimized according to the purpose of display. Excellent visibility like an actual printed matter with characters and images printed thereon can be exhibited.

  That is, according to the present invention, in a conventional electro-optical device including a large number of pixels having openings and non-openings, such as an LCD, a non-opening light-shielding film that has hardly contributed to the display function is more conspicuous. The display is provided on the light output side of the display panel and used for display, and as described later, the display texture, display color, and the like can be significantly improved as compared with the prior art.

[Invention 2] The electro-optical device of Invention 2 is
The electro-optical device according to the invention is characterized in that the light shielding film is formed on the outermost surface of the display panel.
As a result, the light shielding film is directly visually recognized, so that the image quality improvement effect by the light shielding film, such as improvement of texture and coloring, can be exhibited more remarkably.

[Invention 3] The electro-optical device of Invention 3 is
In the electro-optical device according to the first or second aspect of the invention, a polarizing plate is provided on the outermost surface of the display panel, and the light-shielding film is formed on the polarizing plate.
Thus, in addition to the effects of the first and second aspects, the light shielding film can be easily formed by forming the light shielding film on the polarizing plate attached to the end of the panel module of a general display panel.

[Invention 4] An electro-optical device according to Invention 4 comprises
The electro-optical device according to any one of the first to third aspects is characterized in that the shape of the opening is circularly formed by the light shielding film.
As a result, in addition to the effects as in the first to third aspects, by forming the shape of the opening in a circular shape, a false structure according to the direction of the line segment or the like does not occur, and high-quality display can be performed. .

[Invention 5] The electro-optical device of Invention 5 is
The electro-optical device according to any one of the first to fourth aspects is characterized in that the light shielding film has light diffusibility.
That is, since this light shielding film is seen in a reflection mode by external light, by providing light diffusibility, the external light hitting the surface of the light shielding film is diffused and exhibits a white color. Such an easy-to-see display can be exhibited.

[Invention 6] The electro-optical device of Invention 6 is
The electro-optical device according to any one of the inventions 1 to 4, wherein the light-shielding film has a whiteness of 60 to 80%.
As a result, the surface of the light-shielding film becomes white like a normal white printing paper, so that a more easily visible display can be exhibited.

[Invention 7] An electro-optical device according to Invention 7 comprises
The electro-optical device according to a sixth aspect is characterized in that the whiteness of the light shielding film increases or decreases in accordance with the area ratio between the opening and the light shielding film.
That is, if the whiteness of the light-shielding film is 60 to 80% as in the invention 6 in the area ratio of the normal light-shielding film to the opening (approximately 10:90), white like a normal white printing paper. For example, if the area ratio of the openings is too small, the whiteness of ordinary white printing paper can be obtained even if the whiteness of the light shielding film is 60 to 80%. Absent.
Therefore, for example, when the area ratio of the opening is smaller than usual as in the present invention, the whiteness is further increased to increase the whiteness even if the area ratio of the opening is smaller than usual. Whiteness can be obtained.

[Invention 8] The electro-optical device according to Invention 8 includes
The electro-optical device according to any one of the inventions 1 to 7, wherein the light-shielding film is formed by a micro liquid process technique.
That is, this micro liquid process technology is a high-definition droplet discharge printing technology used in ink jet printers and the like. By using such a micro liquid process technology, an extremely fine pixel such as an LCD pixel can be obtained. The light-shielding film can be formed accurately without causing a positional shift with respect to the non-opening.

[Invention 9] The electro-optical device of Invention 9 is
The electro-optical device according to any one of the inventions 1 to 8, wherein the display of the opening is processed in accordance with a color of the light shielding film.
That is, in the above-described invention, since the ratio of the light shielding film (non-opening portion) is larger than usual and further colored, if the display is performed without performing color processing, the light shielding film The display color as a whole may be shifted by being pulled by the color.
Therefore, in the present invention, for example, the display color of the aperture is changed by changing the display of the aperture in accordance with the color of the light-shielding film by hardware processing such as a color filter or processing by image processing correction. be able to.

[Invention 10] An electro-optical device according to Invention 10 includes:
In the electro-optical device according to any one of the inventions 1 to 8, the display of the opening is processed according to the color of the light-shielding film and the ambient light.
That is, as described in the ninth aspect of the invention, the display of the opening may be shifted depending on the color of the light shielding film, and may change depending on the ambient light (external light). The correction is made in consideration of the above.

For example, if the diffusivity of the light-shielding film (non-aperture) is high, the color and brightness of the non-aperture will change due to ambient light. The sensor detects the color of the light-shielding film according to the detected ambient light, and corrects the display of the opening by image processing or the like so as to reduce the influence of the predicted color.
Thereby, not only the color of the light shielding film but also the display color shift of the opening due to ambient light (external light) can be avoided accurately.

[Invention 11] An electro-optical device according to Invention 11 includes:
The electro-optical device according to any one of inventions 1 to 10, wherein a haze value of the opening is 30% or less.

Accordingly, since the diffusibility of the opening is lowered, a clear display can be performed with almost no diffusion of transmitted light passing through the opening.
The reason why the haze value of the opening is defined as 30% or less is that when the haze value exceeds 30%, the occurrence of a diffusion phenomenon can be confirmed by a normal user's naked eye. This is because the occurrence of the diffusion phenomenon is not recognized by the normal user's naked eyes if the ratio is 10% or less. Desirably, this haze value is 10% or less. Moreover, setting the haze value of the opening to 30% or less as described above can be realized relatively easily by configuring the opening with a material having low diffusibility.

[Invention 12] The electro-optical device according to Invention 12 includes:
The electro-optical device according to any one of Inventions 1 to 10, wherein the haze value of the opening is 30% or less, and the haze value of the non-opening is 50% or more.
As a result, it is possible to achieve a clear display with almost no diffusion phenomenon of transmitted light passing through the opening as in the case of the invention 11, and the haze value of the non-opening is set to 50% or more. The diffusibility of the image becomes high, and a display with less reflection can be realized on the entire screen.

  Here, the reason why the haze value of the opening is defined as 30% or less (preferably 10% or less) is the same reason as that of the invention 11, and the haze value of the non-opening is 50% or more. The reason is that if the value is less than 50%, sufficient light diffusibility cannot be obtained, and a clear reflection phenomenon occurs, preferably 80% or more.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a pixel unit of a display panel of a transmissive color LCD using an LED backlight as a light source in the electro-optical device according to the present invention, and FIG. 2 is a plan view thereof. is there.
In the figure, P represents each pixel constituting the display panel, and this pixel P has a lower alignment film 16, a transparent pixel electrode 14, and a lower side on the lower side of the liquid crystal layer 18 as a reference. The glass substrate 12, the lower polarizing layer 10, and the upper alignment film 20, the transparent solid electrode 22, the upper glass substrate 24, and the upper polarizing layer 26 are sequentially laminated on the liquid crystal layer 18, and the back surface thereof. Light of each color of RGB is projected at regular time intervals from a backlight composed of LEDs provided on the side, and the light passes through the layers 10, 12, 14, 16, 18, 20, 22, 24, 26 to the outside from the surface. It comes to emit light.

Further, a light shielding film S is provided on the pixel P (on the light output side) so as to cover a non-opening portion of each pixel P, that is, a portion that does not affect the transmission of light around each pixel.
FIG. 2 shows the arrangement and shape of the pixels P of the display panel. The hatched circles in the figure represent openings, and the halftone dots in the figure represent non-openings having light shielding properties. is there. In addition, dotted lines in the figure indicate a pixel matrix, and each pixel P is controlled in units of this pixel matrix.

Here, the circle of the opening is not a circle of the pixel electrode or the like, but is realized by making the light-shielding non-opening, that is, the light-shielding film S in this way. Has a general rectangular structure.
If a circle is used as the shape of the opening of each pixel P in this way, a fake structure or the like caused by the line segment direction does not occur, and a clear and easy-to-view display can be achieved. Therefore, when the non-opening is used effectively as in the present invention, the circular opening is effective.

In addition, when considering a square opening, there are problems in image quality, such as the presence of electrodes or uneven orientation at the four corners. However, the effect on the image quality due to the reduction of the opening area is considered to be small.
In the present invention, the light shielding film S is not only provided on the surface side of the pixel P as described above, but the light shielding film S is optimized according to the purpose of display.

Specifically, if the light-shielding film S is formed of a material having a high light diffusibility (white material), a white surface having a high light diffusibility exists on the outermost surface of the display panel. The surface has a real paper-like texture, and a more easily visible display can be obtained.
As the material having high light diffusibility, for example, a diffusing material such as silica, mica, and titania can be used, and the surface of the display panel is obtained by a known micro liquid process or printing technique using a dispersion liquid in which the diffusing material is dispersed. It can be easily obtained by coating and printing.

In this case, the light diffusibility of the light shielding film S is not particularly limited. However, when a numerical value of whiteness is used as an index for expressing the whiteness of paper, In general paper, the whiteness is about “60 to 80%”. Therefore, it is desirable to set the diffusion material so as to be within this range.
For example, when it is desired to set the whiteness to be slightly calm, the whiteness is set to “60%”, and when the whiteness is desired to be a bright image, the whiteness is set to “80%”. It is also possible to control by whiteness.

Further, when the area ratio of the non-opening portion is smaller than that of the opening portion, for example, when it is “10%” or less with respect to the area of the opening portion, the whiteness is set to “80%” and “white” In such a case, the whiteness may be further increased by about “10 to 20%”.
Further, when the surface of the light shielding film S is made white as described above, it is not always necessary to make the entire surface white. For example, even if a circular white film W is formed on the light shielding film S as shown in FIG. Similar to the above, it is possible to display an easy-to-view and high-quality texture like real paper.

In addition, when the light diffusion material is partially applied in this way, it can be easily formed with high accuracy by using a micro liquid process (droplet discharge technique) using an ink jet printer technique. By partially forming in this way, waste of materials can be eliminated, cost reduction and environmental load can be reduced.
In addition, by creating a high transmittance (low diffusibility) state in the opening, contrary to the non-opening, not only can a clear display be achieved, but the transmitted light is not diffused and white blurred. Therefore, clear display with high saturation can be performed.

  In this case, there is an adverse effect that the specular reflectance increases and the reflection on the screen increases, but in the case of the present embodiment, the non-opening portion has a high light diffusibility, so the reflection of the screen Since there is almost no blur, the opening can obtain a clear display with little reflection even with a clear display. Here, the light diffusibility can be expressed by a haze value. If the haze value of the opening is 30% or less and the haze value of the non-opening is 50% or more, such an effect is remarkably exhibited. can do.

Note that the transmissive color LCD having such a configuration can express a color by a single pixel (pixel) P by field sequential driving, and an RGB sub-pixel like an RGB sub-pixel often used in a general LCD. It is possible to avoid image quality deterioration such as false color due to the arrangement of pixels.
Next, FIGS. 4 and 5 show the application of the present invention to a transmissive color LCD having RBG subpixels using a general color filter.

FIG. 4 shows the pixel arrangement and shape. The hatched rectangle in the figure indicates an opening, and the halftone dot in the figure indicates a non-opening having light shielding properties.
The major difference in structure between the display panel P of the transmissive color LCD and the display panel P is that, as shown in FIG. 5, the light-shielding film S is located below the upper polarizing layer 26, and at the opening thereof. The RGB color filters F are provided.

A backlight composed of a general white cold-cathode tube is provided on the back side of the display panel P, and the light from the backlight is transmitted from the respective layers 10, 12, 14, 16, 18, 20, 22, Color display is performed by passing light through the openings 24 and 26 and the color filter F and exiting from the openings.
Further, by forming the color filter F and the light shielding film S as a single layer, it is possible to perform reliable light shielding and color generation, and to improve image quality.

Further, by integrating the color filter F and the light shielding film S, even if they are slightly shifted, there is little influence on the appearance, and high image quality can be maintained regardless of the manufacturing accuracy.
In the case of the present embodiment, since the surface of the light-shielding film S serving as a non-opening portion reflects external light and always emits white light, it is necessary to perform color display in consideration of this. Furthermore, in the case of reflected light, the color temperature and brightness of the reflected light change depending on the external light, so some external light sensor should be installed and color display should be performed based on the information of the external light detected by the sensor. Thus, high-quality display can be performed regardless of outside light. Further, the color filter F and the light shielding film S can be bonded together with high accuracy by alignment using an alignment mark that is generally performed.

Further, the light shielding film S and the color filter F may be provided on the outermost surface thereof as shown in FIG. 1. However, if the light shielding film S and the color filter F are provided on the lower side of the polarizing layer 26 as in the present embodiment, the texture is somewhat lowered. However, since the user or the like does not directly touch the light shielding film S, the light shielding film S can be reliably prevented from being contaminated, damaged or worn.
Next, FIG. 6 shows a case where the present invention is applied to a reflective monochrome LCD.

  As shown in the figure, this reflection type monochrome LCD has a lower substrate 30 as a base, a reflective pixel electrode 32, a lower alignment film 16, a liquid crystal layer 18, an upper alignment film 20, and a transparent solid electrode thereon. 22, an upper glass substrate 24, and a polarizing layer 26 are sequentially laminated, and light (external light) incident from the outside (polarizing layer 24 side) is shown in each of the layers 26, 24, 22, 20, 18, 16, reflected by the reflective pixel electrode 32, and then again passed through each layer 16, 18, 20, 22, 24, 26 and emitted as reflected light from the opening. Yes.

In this way, in the case of a reflective monochrome LCD, black and white are expressed using reflected light emitted from the opening as compared with the backlight type LCD as described above. Is very dark and passes through each layer 16, 18, 20, 22, 24, 26, resulting in unnatural light.
For this reason, even in the case of such a reflective monochrome LCD, if a light shielding film S is provided on the surface and the surface is formed of a highly diffusible white material, whiteness close to that of real paper can be exhibited. Natural, easy-to-see “white” display can be performed. As a result, it is possible to realize a display that is easy to see and less tiring, especially when displaying a document or the like.

The pixel array may have a circular opening as shown in FIG. 2, but is not limited to this, and a square (rectangular) opening as shown in FIG. It may have a part.
In this embodiment, an example of an LCD is shown as an electro-optical device. However, the present invention is not limited to this, and any other display device, for example, a CRT (cathode-ray tube) that has been widely used in the past is used. Electroluminescence devices attracting attention as next-generation display monitors, especially organic electroluminescence devices, inorganic electroluminescence devices, plasma display devices, LED (light emitting diode) display devices, electrophoretic display devices, thin cathode ray tubes, The present invention can also be applied to a small television using a liquid crystal shutter or the like, an apparatus using a digital micromirror device (DMD), a field emission display (FED), a surface-conduction electron-emitter display (SED), or the like.

It is sectional drawing which shows one Embodiment of transmissive color LCD. It is an enlarged plan view showing an example of a pixel array. It is an enlarged plan view showing an example of a pixel array. It is an enlarged plan view showing an example of a pixel array. It is sectional drawing which shows one Embodiment of transmissive color LCD. It is sectional drawing which shows one Embodiment of reflection type monochrome LCD. It is an enlarged plan view showing an example of a pixel array.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lower polarizing layer, 12 ... Lower glass substrate, 14 ... Transparent pixel electrode, 16 ... Lower alignment film, 18 ... Liquid crystal layer, 20 ... Upper alignment film, 22 ... Transparent solid electrode, 24 ... Upper glass substrate, 26: upper polarizing layer, 30: lower substrate, 32: reflective pixel electrode, F: color filter, P: pixel, S: light shielding film, W: white film.

Claims (12)

An electro-optical device including a display panel having an array of pixels having an opening and non-opening portion provided with a light shielding film on the light outgoing side of the display panel so as to cover the non-opening portion, wherein the light-shielding film An electro-optical device, which is optimized according to a display purpose.   2. The electro-optical device according to claim 1, wherein the light shielding film is formed on an outermost surface of the display panel.   2. The electro-optical device according to claim 1, wherein a polarizing plate is provided on the outermost surface of the display panel, and the light shielding film is formed on the polarizing plate.   The electro-optical device according to claim 1, wherein the opening is formed in a circular shape by the light shielding film.   The electro-optical device according to claim 1, wherein the light-shielding film has light diffusibility.   5. The electro-optical device according to claim 1, wherein the light-shielding film has a whiteness of 60 to 80%. 6.   The electro-optical device according to claim 6, wherein the whiteness of the light-shielding film increases or decreases according to an area ratio between the opening and the light-shielding film.   8. The electro-optical device according to claim 1, wherein the light shielding film is formed by a micro liquid process technique.   9. The electro-optical device according to claim 1, wherein the display of the opening is processed according to the color of the light shielding film.   9. The electro-optical device according to claim 1, wherein the display of the opening is processed in accordance with a color of the light-shielding film and environmental light.   The electro-optical device according to claim 1, wherein the opening has a haze value of 30% or less.   The electro-optical device according to claim 1, wherein the opening has a haze value of 30% or less and the non-opening has a haze value of 50% or more. apparatus.

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