JP2009245743A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the degradation of image quality in an image display device forming a black matrix using a divided exposure. <P>SOLUTION: The image display apparatus includes a plurality of light-emitting areas formed on a substrate, and a black matrix equipped with a plurality of openings fitted on the substrate for zoning a plurality of light-emitting areas. The black matrix has a nonlinear virtual boundary line 13a extended to its inside face, and an alignment pattern of the openings is changed with the virtual boundary line 13a as a boundary. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image display apparatus having a black matrix, and more particularly to an arrangement pattern of openings in a black matrix.

  An image display device that displays an image by irradiating a plurality of light emitting regions including a phosphor with electrons emitted from an electron source is known. In this type of image display device, a black matrix having a plurality of openings for defining a light emitting region is provided on a substrate on which the light emitting region is formed. As described in Patent Document 1, in the conventional black matrix, the openings are periodically arranged in a line without being disturbed in order to ensure image quality.

  In general, the black matrix is formed by applying a paste obtained by mixing a negative photosensitive resin to a metal oxide on a glass substrate, and then exposing and developing. In the case of using a negative photosensitive resin, the metal oxide remains in a region where light is irradiated and is removed in a region where light is not irradiated. Therefore, at the time of exposure, a mask that blocks a region to be an opening, that is, a region where the metal oxide is to be removed, and transmits light only in a region where the metal oxide remains is used.

By the way, with the recent enlargement of the screen, it is becoming difficult to perform full screen batch exposure with a single mask. When manufacturing a black matrix for a large-sized image display device, so-called continuous exposure is required in which one screen is divided into a plurality of areas, and each divided area is individually exposed. The connection part of each area | region in a joining exposure is linear. That is, it is possible to pattern the entire screen by preparing a rectangular mask and repeating the exposure and development a plurality of times.
Japanese Patent Laid-Open No. 2003-22769

  In splicing exposure, mask misalignment (alignment misalignment) inevitably occurs within the range of alignment accuracy. As a general deviation amount, it is necessary to allow about ± 1.5 μm when a mirror projection aligner is used, and about ± 3 μm when a proxy exposure machine is used. This mask misalignment occurs along the connection between each exposure region and the adjacent exposure region. Usually, the connection portion coincides with a line that bisects the screen. In the case of a horizontally long general image display device, this connection portion coincides with a center line that extends vertically across the screen. For this reason, the openings of the black matrix are simultaneously shifted on the left and right along the center line in the vertical direction of the screen. The direction of the shift may be the vertical direction of the screen, the horizontal direction, or a combination thereof, but if it is shifted up and down, the image becomes asymmetrical on the left and right, and if it is shifted left and right, the image is unnatural in the area along the center line of the screen In either case, the image quality is greatly affected.

  FIG. 9 shows a general shape of a division mask in the prior art and a schematic view of a screen obtained thereby. As shown in FIG. 9A, a divided mask pattern 122 divided along a line corresponding to the center line of the screen is formed at the center of the mask 121 so as to be within an area that can be exposed. Referring to FIG. 9B, which is a partially enlarged view of FIG. 9A, the mask pattern 122 is formed with dots 124 that are areas not irradiated with light. The dots 124 correspond to the openings of the black matrix because a negative material is used as the photosensitive resin. After exposing the half surface of the black matrix, the entire surface is exposed by rotating the mask 121 180 degrees and exposing the remaining half surface. When exposure is performed using this mask pattern 122, the dots 124 are arranged in the x and y directions around the connecting portion 123 from the broken line position to the solid line position in FIG. It will shift by Δx and Δy. In the figure, the dot 124 is shifted rightward and downward, but it may be shifted leftward or upward.

  A pattern as shown in FIG. 10 is also conceivable as a mask division pattern. As shown in FIG. 10A and FIG. 10B, which is a partially enlarged view thereof, a mask pattern 122a that is divided so as to straddle the center line 123a of the black matrix is formed on the mask 121a. Also in this case, as in the case of FIG. 9, the dots 124a are shifted in the x direction and the y direction. In addition to this, as shown in FIG. 10C, the black matrix is over-exposed over the range of the width W through the opening of the mask pattern 122a which has been displaced. For this reason, the opening shape of the black matrix itself is also different from the opening shape of the region not subjected to the overexposure. As a result, the opening pattern of the black matrix is divided into three areas: a left area of the screen, a center band area having a different opening shape from the left area, and a right area whose opening position is deviated from the left area. Rather it gets worse.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a black matrix opening array pattern capable of suppressing deterioration in image quality in an image display device that forms a black matrix using continuous exposure. .

  An image display device of the present invention has a plurality of light emitting regions formed on a substrate, and a black matrix provided on the substrate and having a plurality of openings that define the plurality of light emitting regions. , Having a non-linear virtual boundary line extending in the plane of the black matrix, and the arrangement pattern of the openings changes with the virtual boundary line as a boundary.

  The black matrix is divided by non-linear virtual boundaries. For this reason, compared with the case where it divides | segments by the linear virtual boundary line, the effect equivalent to dividing | segmenting on both sides of a wide strip | belt-shaped area | region produces visually. In other words, the wide area acts as a buffer band that makes the deviation of the opening arrangement pattern of the black matrix on both sides of the virtual boundary line inconspicuous. For this reason, in the image display apparatus of this invention, the fall of image quality can be suppressed.

  Hereinafter, an embodiment of an image display device of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of an image display apparatus according to the present invention. 1A is a schematic cross-sectional view of the image display device, and FIG. 1B is a schematic plan view of the inner surface side of the first substrate as viewed from the line 1b-1b in FIG. 1A. Show. The image display device 1 includes a first substrate 2 and a second substrate 3 that are opposed to each other at a predetermined interval. As shown in FIG. 1B, the first substrate 2 includes a plurality of light emitting regions 5 including a phosphor 4 and a black matrix 6 having a plurality of openings 8 that define the plurality of light emitting regions 5, Is formed. On the second substrate 3, electron-emitting devices 9 are arranged in an array. The electron-emitting device 9 is, for example, a Spindt-type electron-emitting device having a sharp tip shape or a device formed of carbon nanotubes. However, the electron-emitting device 9 is not limited thereto, and any device that emits electrons can be used. Good. A spacer 10 is provided to hold the first substrate 2 and the second substrate 3 at a predetermined interval.

  In order to display an image, the electron-emitting devices 9 formed on the second substrate 3 are driven in matrix, and desired electrons are emitted from the desired electron-emitting devices 9. At the same time, a high voltage of, for example, about 10 kV is applied to the metal back 11 of the first substrate 2, and the emitted electrons are accelerated by the high voltage applied to the metal back 11 to fly along the locus 12. It collides with the phosphor 4. The phosphor 4 is excited and emitted by the colliding electrons, and a desired image is displayed. The image display device 1 is not limited to such an electronic excitation type image display device as long as the image display device has a black matrix 6 on the first substrate 2 and has the opening as a light emitting region. A device (LCD) or a plasma display device (PDP) can also be an object of the present invention.

  The manufacturing method of the first substrate 2 is roughly as follows. First, a black matrix material having photosensitivity is applied onto a glass substrate and patterned by exposure and development. As the black matrix material, a paste in which a photosensitive resin is mixed with a metal oxide is used as in the prior art, and a negative material is used as the photosensitive resin. The exposure process is performed in two steps, and one image region is formed by joining the two exposures. Next, the phosphor 4 is formed in the opening 8 of the black matrix 6 by pattern printing, for example. Next, a metal back 11 made of, for example, aluminum (Al) is formed. Thereafter, the first and second substrates 2 and 3 are opposed to each other through the spacer 10 to form a sealed envelope, and the inside thereof is evacuated to form the image display device 1.

  FIG. 2 shows a schematic diagram of the shape of the division mask according to the present invention and the screen obtained thereby. FIG. 2A is a plan view of the mask 21a, and FIG. 2B is a partially enlarged view of the mask 21a. In these drawings, the white portion is a transparent portion that transmits light. The dark portion is a light non-transmitting portion composed of a large number of dots 24, and each dot 24 corresponds to each opening 8 of the black matrix 6. A number of similar dots are formed inside the mask pattern 22a surrounded by the three straight lines and the broken line in FIG. 2A, but the display is omitted to make the drawing easier to see. In addition, the broken line is actually a stair-like broken line connected in a zigzag shape as shown in FIG.

  In the exposure, first, the range S1 enveloping the mask pattern 22a in FIG. Next, as shown in FIG. 2C, a mask 21aa having a mask pattern 22aa which has a boundary line complementary to the mask pattern 22a and matches the actual black matrix shape together with the mask pattern 22a. Prepare. Then, using the mask 21aa, the range S2 enveloping the mask pattern 22aa is exposed. The boundary lines 14a and 14aa of the mask patterns 22a and 22aa are not linear but have an intricate zigzag shape. In order to expose the zigzag pattern, the boundary lines 14a and 14aa have a width L along the boundary line of the mask patterns 22a and 22aa. The area is exposed twice.

  The black matrix 6a created as a result is a pattern that is divided into two at the center by a zigzag virtual boundary line 13a consisting of a broken line, as shown in the schematic diagram of the screen of FIG. 2 (d). . The virtual boundary line 13a substantially matches the pattern of the boundary lines 14a and 14aa of the mask patterns 22a and 22aa, but does not exactly match due to the positional deviation of the masks 21a and 21aa. To be precise, it should be noted that the virtual boundary line 13a is an area having a certain width defined by the boundary line 14a of the mask pattern 22a and the boundary line 14aa of the mask pattern 22aa. On both sides of the zigzag virtual boundary line 13a, the arrangement pattern of the openings 8 of the black matrix 6a is usually changed due to the displacement of the masks 21a and 21aa. However, because of the zigzag virtual boundary line 13a, the deviation of the aperture arrangement pattern is not linear, but occurs along the zigzag virtual boundary line 13a, and deterioration of visibility is suppressed.

  This is considered to be because the boundary where the periodic disturbance of the opening 8 of the black matrix 6a occurs is not linear but zigzag, thereby obscure the boundary. Visibility hindrance is due to having a clear pattern mask boundary (hereinafter, the boundary lines 14a and 14aa of the mask patterns 22a and 22aa and the connection part 123 of the prior art are collectively referred to as a mask boundary). It is thought to occur. When overlay exposure is performed using a simple linear mask pattern, the change in the aperture pattern is visually clear on the left and right of the linear mask boundary, and the shift on the left and right is easily recognized. That is, when a linear mask boundary is used, a mask position shift occurs simultaneously on the left and right sides of the linear mask boundary, so that a sudden position shift of the light emission point pattern is easily recognized at the mask boundary. On the other hand, when a zigzag mask boundary is used, the region of the width L in the figure becomes a transition region or a buffer region of the mask misalignment for the screen observer, which is equivalent to a gradual change in the mask misalignment. Effects are obtained, and the disturbing feeling on visibility is suppressed. Thus, since it is considered that the formation of a clear mask boundary at the time of joint exposure is a factor causing a sense of disturbing visibility, it is effective to make the boundary pattern a zigzag shape as a means for avoiding this.

  By the way, as described above, in the case of using a negative photosensitive resin, in order to reliably expose the joint portion due to the positional deviation of the mask, the connection portion of each exposure region with the adjacent exposure region is used. A region for overexposure is provided. For this reason, the double-exposed region is given twice as much dose as the normal region, and the photochemical reaction further proceeds, resulting in a characteristic change. Since the characteristic change is accompanied by an increase in reflectance, the overexposed area becomes a black matrix altered pattern having a higher reflectance than other areas.

  In the prior art, as shown in FIG. 9C, the region near the connection portion 123 of the mask pattern 122 is exposed twice, and the black matrix has a very narrow linear alteration pattern 125. It is formed. Since the black matrix is located on the outermost layer of the display surface, the black matrix alteration pattern 125 may be visually recognized as a linear unevenness on the black matrix. This linear unevenness is mainly recognized when the image display device is not operated, but is not preferable from the viewpoint of the interior property and the design property of the image display device.

  On the other hand, in the case of the present embodiment, the region of width L that is overexposed includes the zigzag virtual boundary line 13a, and the black matrix alteration pattern 25a is averaged in the region of width L. As a result, the unevenness of the screen due to the alteration becomes less noticeable visually. In other words, since the change in the reflectance of the black matrix 6a is dispersed in the region of the width L, the unevenness of the screen is hardly visually recognized.

  As described above, the present embodiment is characterized in that the shape of the mask connection portion in the joint exposure of the black matrix is a zigzag shape. As a result, it is possible to suppress the image disturbance caused by the periodic disturbance of the light emitting point position and the distortion of the reflected image in the connection exposure unit having a high reflectance when the image display device is not operated.

  As described above, the mask misalignment can occur about ± 1.5 μm when the mirror projection aligner is used, and about ± 3 μm when the proxy exposure machine is used. When these apparatuses are used, the change in the arrangement pattern of the openings occurs as a positional deviation within 3 μm of the arrangement pattern of the openings 8 on both sides of the virtual boundary line 13a.

  Other division patterns of the black matrix in the image display device according to the present invention are shown in FIGS. In any of the embodiments, the zigzag mask boundary is used to make the positional deviation of the arrangement pattern of the black matrix openings and the unevenness of the screen due to the difference in the reflectance at the overlapped exposure portion less noticeable.

  In each figure of FIGS. 3-7, (a) is a top view of a mask, (b) is the elements on larger scale of a mask, (c) is the schematic of a screen. In each figure, the boundary line of the mask pattern is shown only for one mask pattern, but the boundary line of the other mask pattern has a shape complementary to the boundary line of the illustrated mask pattern.

  In the embodiment shown in FIG. 3, the mask pattern boundary line 14b, and thus the formed virtual boundary line 13b, is formed with an equal length cut for each line, and the regions on both sides of the virtual boundary line 13b are nested in each other. It has a different shape.

  In the embodiment shown in FIG. 4, the mask pattern boundary line 14c, and thus the formed virtual boundary line 13c, are alternately formed with cuts having different lengths for each line, and regions on both sides of the virtual boundary line 13c. Have nested shapes.

  In the embodiment shown in FIG. 5, the boundary 14d of the mask pattern, and hence the formed virtual boundary 13d, is formed with cuts made up of a plurality of continuous equal length lines, and the regions on both sides of the virtual boundary 13d are mutually connected. It has a nested shape.

  In the embodiment shown in FIG. 6, a cut formed by a plurality of continuous equal-length lines is formed, but the length of the cut is increased or decreased with respect to the adjacent cut. The boundary line 14e of the mask pattern, and hence the formed virtual boundary line 13e, has a shape close to an S shape as a whole.

  In the embodiment shown in FIG. 7, random nests having no periodicity are formed on the boundary line 14f of the mask pattern, and thus on the formed virtual boundary line 13f.

  All of these patterns have an effect of visually suppressing image distortion and non-uniformity of the reflection pattern caused by the displacement of the mask of the black matrix.

  FIG. 8 shows another division pattern of the black matrix, and contrasts the effect of the present invention with the prior art. FIG. 8A shows an example of a black matrix created using a linear mask pattern according to the prior art. In this example, the right part in the figure is shifted downward relative to the left part. FIG. 8B shows a divided mask pattern according to an embodiment of the present invention. The right part in the figure is shifted downward with respect to the left part as much as in the case of FIG. Referring to FIG. 8 (a), it can be seen that the left and right opening patterns are shifted all at once along the linear mask boundary, and the opening shift is conspicuous. On the other hand, in the case of FIG. 8B, in the position I, the uppermost two stages are shifted left and right, but the other stages are not shifted. At position II, the fifth and sixth steps from the top are shifted from left to right, but no shift occurs at the other steps. Thus, it can be seen that the portions where the deviation occurs are dispersed, and the visual deviation is hardly noticeable.

  In the example shown in FIGS. 2 to 6 and 8, the black matrix is divided into two regions that are point-symmetric with respect to the center points C2 to C6 and C8 of the black matrix by the virtual boundary line. In such a divided pattern, it is possible to first expose one side with one mask and then rotate the same mask 180 degrees to expose the rest, so it is necessary to prepare separate masks exclusively for left and right This is advantageous because it reduces the manufacturing cost.

  Although not shown, the shape of the virtual boundary line, that is, the boundary line of the mask pattern, may be composed of a waveform, a sine wave, or any other curve, or a combination of these curves and a broken line. May be. In short, the virtual boundary line may be any non-linear line, and may have a non-zero width in a direction orthogonal to the direction in which the line extends. By having a non-zero width, the non-zero width region becomes a buffer region for visually relieving the positional deviation of the light emitting point pattern.

  Further, in the embodiment described above, the screen is divided into the left and right parts, but the form of the division is not limited to this. Also good. Furthermore, the virtual boundary line may be closed inside the black matrix without reaching the end of the black matrix, as in the central region when dividing vertically and horizontally into nine, but such a form is also included in the present invention. It is. That is, the virtual boundary line may be a non-linear shape extending in the plane of the black matrix.

1 is a schematic view of an image display device according to the present invention. It is a figure which shows the outline of the screen obtained by the shape of the division | segmentation mask pattern based on this invention, and it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the other division | segmentation pattern of a black matrix, and the outline of the screen obtained by it. It is a figure which shows the shape of the general division | segmentation mask pattern in a prior art, and the outline of the screen obtained by it. It is a figure which shows the outline of the other divided mask pattern in a prior art, and the screen obtained by it.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 1st board | substrate 3 2nd board | substrate 4 Phosphor 6 Black matrix 8 Aperture 13a-13f Virtual boundary line

Claims (5)

A plurality of light emitting regions formed on the substrate;
A black matrix provided on the substrate and having a plurality of openings defining the plurality of light emitting regions;
Have
The image display device, wherein the black matrix has a non-linear virtual boundary line extending in a plane of the black matrix, and the array pattern of the openings changes with the virtual boundary line as a boundary.   The image display apparatus according to claim 1, wherein the virtual boundary line is a polygonal line.   The image display device according to claim 1, wherein the change in the arrangement pattern of the openings occurs as a positional deviation within 3 μm of the arrangement pattern of the openings on both sides of the virtual boundary line.   The image according to any one of claims 1 to 3, wherein the black matrix has a linear region having a reflectance different from that of other regions, and the linear region includes the virtual boundary line. Display device.   The image display device according to claim 1, wherein the black matrix is divided into two regions that are point-symmetric with respect to a center point of the black matrix by the virtual boundary line.

Images