JP3540896B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to improving the display quality of a liquid crystal display device, and more particularly to improving the display quality of a negative type STN liquid crystal display device having a color filter layer using a photosensitive resin material as a light-shielding filter.
[0002]
[Prior art]
FIG. 16 is a cross-sectional view of a liquid crystal display element having a color filter layer (hereinafter, referred to as a color liquid crystal display element) using a conventional photosensitive resin material for a light shielding filter. As shown in the figure, a pair of substrates 1 and 2 made of a transparent and insulating material such as glass are disposed to face each other, and a color filter layer 3, an overcoat layer 6, a display An electrode 7a and an alignment film 8a are formed in this order, and a display electrode 7b, an insulating film 9, and an alignment film 8b are formed in this order on the opposite surface of the other glass substrate 2. The display electrodes 7a and 7b are arranged in a matrix such that striped electrodes are orthogonal to each other. Then, these substrates 1 and 2 are bonded together with a sealing material 12 containing glass beads 11 arranged on the outer periphery of the effective display area via plastic beads 10 for cell gap control arranged in the effective display area, Liquid crystal is injected and sealed in the gap between the glass substrates 1 and 2 surrounded by the sealing material 12, and a liquid crystal layer 13 is formed.
[0003]
Next, a method of manufacturing the color filter layer 3 when a photosensitive resin material is used as a light-shielding filter will be described. FIG. 17 is a view showing a manufacturing method (post-attached black mask method) for forming the black mask 5 after forming the R, G, B color filters 4, and FIG. , G and B are diagrams showing a manufacturing method (pre-attached black mask method) for forming color filters 4.
[0004]
In the method for manufacturing the color filter layer 3 of the post-attached black mask method shown in FIG. 17, first, as shown in FIG. 17A, a color filter 4 of each of R, G, and B is applied to the substrate 1 by a predetermined method. After the formation, next, as shown in FIG. 17B, a photosensitive resin light-shielding material 14 containing a light-shielding material such as carbon on the entire surface is formed by a printing method, a spin coating method, or a film laminating method, and specified. UV light of a wavelength is exposed from the back surface. Thereafter, as shown in FIG. 17C, development is performed to form a black mask 5 between each of the R, G, and B color filters 4 and on the outer peripheral portion of the effective display area, as shown in FIG. 17D. And a method of baking in an oven or the like to cure by thermal polymerization.
[0005]
At this time, as disclosed in JP-A-6-273743, a black matrix layer (light-shielding property) is also provided on the seal portion in order to make the cell gap uniform, which is a problem of the STN-type liquid crystal display element, as disclosed in JP-A-6-273743. In general, a filter is provided, and the color filters 4 and the black masks 5 of the respective hues are adjusted to have the same film thickness. Further, the film thickness of the black mask was the same in both the effective display area and the outer peripheral portion of the effective display area.
[0006]
FIG. 18 shows a method of manufacturing the color filter layer 3 of the pre-attached black mask method. First, as shown in FIG. 18A, a photosensitive resin light-shielding material 14 containing a light-shielding material such as carbon is printed on the substrate 1. After being exposed by UV light of a specific wavelength from the surface using a photomask 15 and then developed to form R, G, B as shown in FIG. The black mask 5 is first formed between the color filters of each hue and on the outer peripheral portion of the effective display area. Next, as shown in FIG. 18 (c), after baking in an oven or the like to be thermally polymerized and cured, as shown in FIG. 18 (d), a manufacturing method for forming R, G, B color filters 4 It is. As a method of forming the color filter 4, a process of exposing any one of the R, G, and B color filters to UV light of a specific wavelength from the back surface and developing and developing the same is repeated between the R, G, and B black masks. There is a method of forming a B color filter, or a method of making the UV light of a specific wavelength larger than the surface between the black masks so that the edges of the R, G, and B color filters cover the black mask.
[0007]
Here, as in the case shown in FIG. 17, the black mask 5 and the R, G, B color filters 4 are generally designed to have substantially the same film thickness. In the case of the manufacturing method shown in FIG. 18, since the periphery of the R, G, and B color filters 4 partially overlaps the black mask 5, the shape of the color filters in the effective display area and the continuity of the color filters in the outer periphery of the effective display area. In general, a dot design in the effective display area is extended to the outer periphery of the effective display area to maintain uniformity (approximately ± 0).
[0008]
The thickness of the black mask was the same in both the effective display area and the outer periphery of the effective display area. However, the film thickness is reduced by thermal polymerization in the baking process of the black mask, and there is a film reduction in the brush cleaning or solvent cleaning in the next process.Thus, although the average thickness of the finished black mask can be adjusted, The in-plane variation of the black mask was as large as about ± 0.25 μm with respect to the average value. In order to solve this problem, Japanese Patent Application Laid-Open No. 3-252622 proposes a method for solving variations in the thickness of the black mask by performing exposure from the substrate surface in addition to exposure from the back surface of the substrate. I have.
[0009]
Further, as shown in FIG. 19, the R, G, and B color filters 4 in the effective display area and the dot pattern of the black mask 5 are continuously formed up to the vicinity of the seal on the outer peripheral portion of the effective display area, and the effective display is performed. There is a method of making the level difference between the area and the outer periphery of the effective display area uniform. In this case, since dot patterns having the same film thickness are continuously formed, the variation in the level difference between the effective display area and the outer peripheral portion of the effective display area is extremely small, and the uniformity is high, but the outer peripheral portion of the effective display area is monochromatic black. However, there is a drawback that light escapes.
[0010]
[Problems to be solved by the invention]
2. Description of the Related Art In recent years, with respect to liquid crystal display elements, particularly STN color liquid crystal display elements, luminance unevenness (washout) due to heat factors of a backlight light source, luminance unevenness (washout) due to sime thickness factor, and wiring resistance around a screen of the liquid crystal display element, particularly near a black frame. High display quality such as luminance unevenness (gradation) on the left and right sides of the screen due to a voltage drop, high contrast of 30 or more, luminance of 100 cd or more, response speed of 200 ms or less, and high reliability and high reliability are required. 30: 1 or more is required. Among the above-mentioned demands, there is a strong demand for uniformity of display quality near the outer periphery of the effective display area, and there is a stronger demand for improvement with respect to uneven brightness (washout) near the outer periphery of the effective display area.
[0011]
That is, in the above-described prior art, (1) when the film thickness of the black mask in the outer peripheral portion of the effective display area is smaller than the film thickness of the color filter and the black mask in the effective display area, there is a step at the boundary. The cell gap in the vicinity of the outer periphery of the effective display area becomes thin, and when the liquid crystal driving voltage is in the ON state, there is a problem that a bright white spot (washout) occurs.
[0012]
(2) When the thickness of the black mask around the effective display area is larger than the thickness of the color filter and the black mask in the effective display area, the cell gap thickness is increased due to the step at the boundary, and When the drive voltage is in the ON state, there is a problem that the vicinity of the outer peripheral portion of the effective display area becomes dark and the in-plane uniformity in the effective display area is impaired.
[0013]
Further, even in the case of (3) above (1) or (2) or when the film thickness of the color filter and the black mask in the effective display area is equal to the film thickness of the black mask in the outer periphery of the effective display area, Due to the demand for smaller and lighter liquid crystal modules, the backlight and the liquid crystal display element are increasingly designed close to each other. The heat generated by the backlight affects the periphery of the liquid crystal display element, and the periphery of the effective display area The retardation of the liquid crystal in the vicinity changes, and the liquid crystal driving voltage in this portion increases, which causes a problem that a washout due to heat occurs.
[0014]
Further, in order to improve the tightness of black (increase the OD (Optical Density) value) in the black frame portion on the outer periphery of the effective display area, it is preferable that the thickness of the black mask is thicker. In order to increase the light transmittance of the entire device and obtain a bright and vivid display quality, it is better to make the R, G, and B color filters thinner, which has a trade-off relationship. In consideration of the above, the design is made such that the film thicknesses of the black mask and the color filter are the same as described above. In other words, it is impossible to intentionally change the thickness of the black mask in the effective display area and the outer peripheral portion of the effective display area by the conventional manufacturing method, and both the improvement of the display quality and the improvement of the optical characteristics are satisfied. Could not.
[0015]
Further, in the prior art shown in FIG. 19, the degree of tightness of black near the outer periphery of the effective display area is clearly worse than when a black mask of a single black color is used.
[0016]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for manufacturing a liquid crystal display element of the present invention includes the steps of: adhering a liquid crystal display element via a sealing material at an outer peripheral portion of an effective display area; Further, at least one of the pair of substrates is formed with a color filter layer made of a photosensitive resin material that causes photopolymerization by absorbing light of a specific wavelength. In the method for manufacturing a liquid crystal display element, the effective display area of the color filter layer comprising the photosensitive resin material , Or a part of the effective display area and the outer periphery of the effective display area Mask and adjust the degree of exposure with light of a specific wavelength from the front side to expose. By firing The color filter layer to the effective display area, Whole area or part of it The layer thickness of , The difference in the layer thickness is determined within the effective display area and Whole or part of it It is characterized in that the thickness of the liquid crystal layer in the vicinity is adjusted to be 0.05 to 0.2 μm larger than the thickness of the central part of the effective display area.
[0019]
Here, the color filter having a hue made of a photosensitive resin material that causes photopolymerization by absorbing light having the specific wavelength is preferably a light-shielding filter.
[0020]
Further, it is preferable that the liquid crystal is an STN liquid crystal in which a twist angle of liquid crystal molecules is changed from 180 degrees to 360 degrees.
[0022]
Further, in the present invention, the effective display area of the color filter layer made of a photosensitive resin material and a portion of the outer peripheral portion of the effective display area are masked, and the exposure amount is adjusted with light of a specific wavelength from the surface side and exposed. The thickness of the color filter layer is increased in a part of the outer periphery of the effective display area with respect to the inside of the effective display area. It is preferable to adjust the amount of exposure so that the thickness of the liquid crystal layer becomes 0.05 to 0.2 μm larger than the thickness of the central portion of the effective display area.
[0023]
The operation of these configurations will be described below.
[0024]
FIG. 11 is an enlarged schematic view of the vicinity of the outer periphery of the effective display area for explaining the operation of the present invention.
[0025]
Within the effective display area, the cell thickness (thickness of the liquid crystal layer) d1 near the outer periphery of the effective display area and other than near the outer periphery of the effective display area, that is, the cell thickness d at the outer periphery of the effective display area and the center of the effective display area. Is d1> d. Here, as a method of making the cell thickness near the outer periphery of the effective display area larger than the cell thickness other than that near the outer periphery of the effective display area, various films (alignment film, display electrode, flattening layer, etc.) on the outer periphery of the effective display area are used. , Color filters, etc.), a thicker film at that portion, and changing the particle size of the spacer near the outer periphery of the effective display area. In the case of a negative liquid crystal display element, this difference in cell thickness appears as a difference in VT curve (voltage-luminance characteristic), which is a display characteristic, as shown in FIG. In FIG. 12, the horizontal axis indicates the applied voltage, the vertical axis indicates the luminance, the solid line indicates the VT curve of the normal portion, and the dotted line indicates the VT curve of the portion where the cell thickness is large. As can be seen from FIG. 12, the larger the cell thickness, the more the rise of the VT curve is delayed, and a luminance difference at the off-state voltage Voff occurs at the boundary between the cell thicknesses d1 and d. In the case of a negative liquid crystal display element, the vicinity of the outer periphery of the effective display area tends to be dark.
[0026]
Further, the aforementioned washout due to the heat of the backlight, which is an object of the present invention, is caused by the fact that the refractive index anisotropy Δn of the liquid crystal near the outer periphery of the effective display area is changed by the heat of the backlight. It is. FIG. 13 shows the VT curve at this time. The solid line shows the VT curve of the normal portion, and the dotted line shows the VT curve of the thermal washout portion. From this figure, the luminance at the time of off-voltage Voff is more than the design value (the center of the effective display area). It turns out that it becomes high near the outer peripheral part. Incidentally, the luminance difference at this time was about 6 cd. In particular, when the liquid crystal display element is a negative type, the display is in a dark state because light is shielded when the off-voltage is turned off, and the human eye is very sensitive to a luminance difference in the dark state. It was recognized as unevenness (experience shows that, in this dark state, human eyes would recognize as a brightness unevenness if the brightness difference exceeded 4 cd). Incidentally, at the time of Von, the light is in a bright state. In this state, the human eyes are insensitive to the luminance, and are difficult to recognize as unevenness.
[0027]
In the configuration of claim 1 of the present invention, the above two phenomena are combined, and as a result, the washout due to heat is reduced. That is, the increase in luminance due to the heat washout at the time of the off voltage Voff is offset by the decrease in luminance due to the difference in cell thickness.
[0028]
Further, as shown in the schematic diagram 14, this combined effect changes depending on the cell thickness difference (d1-d). 14, the horizontal axis indicates the cell thickness difference (d1-d), the vertical axis indicates the luminance difference, the solid line A indicates the effect of thermal washout, the solid line B indicates the luminance difference caused by the cell thickness difference, and the dotted line C Indicates the combined luminance difference. Then, in order to achieve a level (within a luminance difference of 4 cd) that is not recognized as luminance unevenness by human eyes, it is necessary to set the cell thickness difference (d1−d) to 0.05 to 0.2 μm. That is, when the cell thickness difference is smaller than 0.05 μm, the luminance difference becomes 4 cd or more, and luminance unevenness due to thermal washout is observed. If the cell thickness difference exceeds 0.2 μm, on the contrary, the vicinity of the outer periphery of the effective display area becomes dark and is observed as uneven brightness.
[0029]
Further, by using a photosensitive resin material for the black mask of the color filter layer, the thickness control of the color filter layer can be achieved by adjusting the amount of UV light. That is, in FIG. 15, the baking temperature is plotted on the horizontal axis and the film thickness is plotted on the vertical axis, and the exposure amount is adjusted to show the change in the film thickness when the exposure amount is changed from the initial film thickness. By baking, changes occur in the respective film reduction amounts. That is, when the exposure amount is increased, the change in the film thickness is small, and when the exposure amount is increased, the change in the film thickness is large. The present invention can use this relationship to control the final film thickness of the color filter.
[0030]
In addition, the hue of the color filter layer which forms the outer peripheral portion of the effective display area to be thicker is set to black (light-shielding filter). As a result, the light-shielding ratio of the (frame portion) is improved, and the sense of neatness in the outer peripheral portion of the effective display area is improved. In the effective display area, the film thickness of the other color filters (R, G, B) can be adjusted, and the light shielding property of only the peripheral portion can be improved.
[0031]
The STN-type liquid crystal display element has a large change in characteristics with respect to the difference in cell thickness. For example, if the cell thickness changes by 0.05 μm in the effective display area, the STN-type liquid crystal display element looks uneven as a light and shade difference. For this reason, the present invention utilizes this fact in reverse to improve the display quality by providing a difference of 0.05 to 0.2 μm between the cell thickness in the effective display area and the cell thickness near the outer periphery of the effective display area. It can be improved.
[0032]
Further, by masking the inside of the effective display area and irradiating UV light only from the outer peripheral portion of the effective display area from the surface, there is provided a difference in the amount of film reduction of the photosensitive resin material between the effective display area and the outer peripheral portion of the effective display area. It is possible to control the difference in film thickness at the final stage by adjusting the amount of UV light.
[0033]
Also, by masking the inside of the effective display area and a part of the outer periphery of the effective display area, and irradiating only the outer periphery of the effective display area outside the masking with UV light from the surface, the photosensitive area in the effective display area and the outer periphery of the effective display area are exposed. It is possible to provide a difference in the amount of film reduction of the conductive resin material, and it is possible to control the difference in film thickness in the final stage by adjusting the amount of UV light, and furthermore, this difference only in the outer peripheral portion of a specific effective display area. Can be provided.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to Examples.
[0035]
(Example 1)
FIG. 1 is a cross-sectional view of an STN color liquid crystal display device in which a color filter layer is formed by a post-black mask method according to the present invention. 2A to 2F are diagrams showing a method of forming a color filter layer in the order of steps.
[0036]
As shown in FIG. 2A, a film 1 having an initial film thickness of 2 μm for each color is used for a substrate 1 made of a transparent or insulating material such as glass. After a predetermined pattern is formed by the lamination method, as shown in FIG. 2B, the initial film thickness is 2.15 μm in consideration of making the surface side exposure amount in the outer peripheral portion of the effective display area larger than that in the effective display area. A black film 14 made of a photosensitive resin light-shielding material containing a light-shielding material such as carbon black is formed on the entire surface of the substrate by a film laminating method, and exposed to 38 mj of 356 nm I-line UV light from the back side. Thereafter, as shown in FIG. 2 (c), development is performed to form a black mask 5, and then, as shown in FIG. 2 (d), I-line UV light of 356 nm is applied from the front side to 0.5 to 5 mj ( Preferably, the entire surface is exposed. After that, as shown in FIG. 2E, only the black mask portion on the outer peripheral portion of the effective display area is exposed to 50 mj of 356 nm I-line UV light from the front side using the photomask 20, and as shown in FIG. Was baked in an IR oven at 250 ° C. and finally cured. As a result of the final step, the thickness of the color filter layer in the effective display area was 2.0 μm, and the thickness of the color filter layer in the outer peripheral portion of the effective display area was 2.15 μm.
[0037]
On the color filter layer 3, an overcoat layer 6, a display electrode 7a, and an alignment film 8a are sequentially disposed, and on the other hand, on a substrate 2, a display electrode 7b, an insulating film 9, and an alignment film 8b are sequentially disposed. The substrate is opposed to the substrate. The display electrodes 7a and 7b are arranged in a matrix such that the striped electrodes are orthogonal to each other. The plastic beads 10 for cell gap control are evenly distributed in the effective display area, and the periphery is bonded with an epoxy sealant 12 containing glass beads 11 for maintaining the cell thickness, and the twist angle is from 180 ° to 300 °. An STN color liquid crystal display element was prepared by injecting and filling an STN liquid crystal of preferably 240 ° to 260 °.
[0038]
The level difference between the effective display area of the color filter layer of the liquid crystal display element and the outer peripheral portion of the effective display area is +0.15 μm, and the variation of the level difference is +0.1 to +0.2 μm, and the vicinity of the liquid crystal screen in the liquid crystal module state is washed out. The display quality in the effective display area became smooth and uniform. Further, even when the liquid crystal module was turned on for a long time, no light leakage on the liquid crystal screen near the backlight was observed. In the color filter layer, the film hardness of the black mask has been increased, so that the light blocking ratio has been improved, the contrast has been improved to 30: 1, and the tightness of black at the outer peripheral portion of the effective display area has been improved, so that the display quality has been improved. In addition, the entire surface containing alumina or the like can be polished to prevent foreign substances, and the white spot and black spot defects, which are defects of the liquid crystal display element, have been drastically reduced.
[0039]
(Example 2)
FIG. 3 is a cross-sectional view of an STN color liquid crystal display device in which a color filter layer is formed by a post-black mask method according to the present invention. FIGS. 4A to 4F are views showing a method of forming a color filter layer in the order of steps.
[0040]
4A to 4C, the same steps as those in FIGS. 2A to 2C are performed, and the formation of the color filter 4 and the black mask 5 of each of the R, G, and B hues. Thereafter, as shown in FIG. 4D, the entire surface is exposed to I-line UV light of 356 nm from the surface side for 0.5 to 5 mj (preferably 2 mj). Thereafter, as shown in FIG. 4E, a portion of the black mask on the outer peripheral portion of the effective display area by the photomask 21, that is, only the side where the backlight is arranged when incorporated in the liquid crystal module, is further subjected to an I-line of 356 nm. The substrate was exposed to UV light at 50 mj, baked in an IR oven at 250 ° C., and finally cured as shown in FIG. As a result of the final step, the thickness of the color filter layer in the effective display area is 2.0 μm, and the thickness of the color filter layer on the side where the backlight is arranged on the outer periphery of the effective display area is 2.15 μm. Was.
[0041]
A counter substrate on which an overcoat layer 6, a display electrode 7a, and an alignment film 8b are sequentially disposed on the color filter layer 3, and a display electrode 7b, an insulating film 9, and an alignment film 8b are sequentially disposed on the substrate 2. Were adhered to each other with an epoxy sealant 12 containing cell beads 10 for controlling cell gap and glass beads 11 for maintaining cell thickness, and STN liquid crystal was injected and sealed to prepare an STN color liquid crystal display device. The level difference between the effective display area and the outer periphery of the effective display area of the color filter layer on the side where the backlight of the liquid crystal display element is arranged is +0.15 μm, and the variation is +0.1 to +0.2 μm. The level difference between the area and the outer periphery of the effective display area was approximately +0.05 μm. At this time, the vicinity of the liquid crystal screen in the liquid crystal module state was uniform without washout. Further, no light leakage on the liquid crystal screen near the backlight due to long-time lighting was observed. The contrast of the color filter layer has been improved to 30: 1 due to the increase in the film hardness of the black mask, the tightness of black at the outer peripheral portion of the effective display area has been improved, and the display quality has been improved. Thus, it is possible to carry out overall polishing including the above, and the white spot and black spot defects, which are defects of the liquid crystal display element, are also drastically reduced.
[0042]
(Example 3)
FIG. 5 is a sectional view of an STN color liquid crystal display device in which a color filter layer is formed by a black mask method according to the present invention. FIGS. 6A to 6E are diagrams showing a method of forming a color filter layer in the order of steps.
[0043]
On a substrate 1 made of a transparent or insulating material such as glass, a black film made of a photosensitive resin material and having an initial film thickness of 1.9 μm is formed on the entire surface of the substrate by a film laminating method, as shown in FIG. Next, a predetermined pattern is exposed to I-ray UV light of 356 nm by 50 mj using a photomask 15 and developed as shown in FIG. 6B to form a black mask. Next, as shown in FIG. 6C, a portion of the black mask portion on the outer peripheral portion of the effective display area by another photomask 22, that is, only the side where the backlight is arranged when incorporated in the liquid crystal module, is further added. After exposure to 50 mj of 356 nm I-ray UV light and baking as shown in FIG. 6 (d), as shown in FIG. Was formed into a predetermined pattern by a film lamination method, and finally cured in a 250 ° C. IR oven. As a result of the final step, the thickness of the color filter layer in the effective display area was 2.0 μm, and the thickness of the color filter layer in the outer peripheral portion of the effective display area was 2.15 μm.
[0044]
On the color filter layer 3, an overcoat layer 6, a display electrode 7a, and an alignment film 8a are sequentially disposed, and on the other hand, on a substrate 2, a display electrode 7b, an insulating film 9, and an alignment film 8b are sequentially disposed. The substrates were opposed to each other, bonded with an epoxy-based sealant 12 containing cell beads 10 for controlling cell gaps and glass beads 11 for maintaining cell thickness, and liquid crystal was injected and sealed to prepare an STN color liquid crystal display device.
[0045]
The level difference between the effective display area and the outer periphery of the effective display area of the color filter layer of the liquid crystal display element is +0.1 μm, and the variation is +0.05 to +0.15 μm. There is no washout near the liquid crystal screen in the liquid crystal module state. The display became uniform and the display quality in the effective display area became smooth and uniform. In addition, since the color filter layer is exposed from the front side, the black mask film hardness is high, and the film loss is small, so that the light shielding ratio of the black mask is high, and the contrast is improved to 32: 1. The degree of tightness was also improved, and the display quality was improved. Further, the entire surface containing alumina or the like can be polished to prevent foreign matter, foreign matter caused by the color filter layer is almost removed, and white spots and black spots, which are defects of the liquid crystal display element, are also drastically reduced.
[0046]
(Comparative example)
Hereinafter, a comparative example of a liquid crystal display device according to the related art will be described.
[0047]
(Comparative Example 1)
FIG. 7A shows a case where the black mask around the outer periphery of the effective display area is higher than the color filter layer in the effective display area including the R, G, and B color filters 4 by 0.25 μm. Since the step between the effective display area and the outer periphery of the effective display area is large, the cell thickness in the vicinity of the outer periphery of the effective display area becomes thicker. Slow and dark. In addition, since the step between the effective display area and the outer periphery of the effective display area is large, the uniformity of the film surface is deteriorated by the alignment film treatment or the rubbing treatment, and the alignment unevenness, the rubbing stripe unevenness, etc. are easily generated, and the display quality is reduced. Dropped.
[0048]
(Comparative Example 2)
FIG. 7B shows a case where the black mask around the effective display area has the same film thickness as the color filter layer in the effective display area including the R, G, and B color filters 4. As shown in FIG. 9, the backlight 17 and the liquid crystal display element 18 are close to each other, the periphery of the liquid crystal display element 18 due to the heat generated by the backlight 17 is easily affected by heat, and the retardation of the liquid crystal near the effective display area changes. As a result, the liquid crystal drive voltage in this portion increases, and a washout 19 due to heat occurs as shown in FIG. The OD value of the black mask on the outer peripheral portion of the effective display area is 2 to 2.5. When the liquid crystal driving voltage is ON, there is slight light leakage and the light is transparent.
[0049]
(Comparative Example 3)
FIG. 7C shows the case where the black mask at the outer peripheral portion of the effective display area is lower than the color filter layer in the effective display area including the R, G, and B color filters 4 by 0.2 μm or more. In FIG. 8, the cell thickness near the outer periphery of the effective display area is reduced, and as shown in FIG. 8, when the liquid crystal driving voltage is in the ON state, the liquid crystal molecules rise faster and are brighter. Further, when the OD value of the black mask on the outer peripheral portion was 1.5 and it was in the ON state, the display quality was such that the tightness of black was not perfect but transparent.
[0050]
【The invention's effect】
According to the present invention, it is possible to improve the washout on the outer periphery of the liquid crystal screen, particularly the washout due to the heat of the backlight, to provide good display quality, and to achieve high reliability with little white spot and black spot defects and high contrast. It can be provided in an inexpensive way.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a color liquid crystal display device of Example 1.
FIG. 2 is a diagram illustrating a method for manufacturing a color filter layer of Example 1.
FIG. 3 is a cross-sectional view of a color liquid crystal display device of Example 2.
FIG. 4 is a view illustrating a method for manufacturing a color filter layer of Example 2.
FIG. 5 is a cross-sectional view of a color liquid crystal display device of Example 3.
FIG. 6 is a view illustrating a method for manufacturing a color filter layer of Example 3.
FIG. 7 is a sectional view of a color liquid crystal display element of Comparative Examples 1 to 3.
FIG. 8 is an explanatory diagram illustrating luminance unevenness near the outer periphery of an effective display area in a color liquid crystal display element of a comparative example.
FIG. 9 is an explanatory diagram showing an arrangement relationship between a backlight of a liquid crystal module and a liquid crystal display element.
FIG. 10 is an explanatory diagram illustrating a state in which a washout occurs due to heat of a backlight.
FIG. 11 is an explanatory view showing the vicinity of the outer periphery of the effective display area of the color liquid crystal display element according to the present invention.
FIG. 12 is a diagram showing a voltage-luminance characteristic depending on a cell thickness difference.
FIG. 13 is a diagram showing voltage-luminance characteristics due to the influence of heat.
FIG. 14 is a diagram for explaining a combined effect of a luminance characteristic by thermal washout and a luminance characteristic by cell thickness.
FIG. 15 is a diagram illustrating a change in the thickness of a color filter layer depending on the exposure amount.
FIG. 16 is a cross-sectional view of a conventional color liquid crystal display device.
FIG. 17 is a diagram illustrating a method of manufacturing a color filter layer by a post-attached black mask method.
FIG. 18 is a diagram illustrating a method of manufacturing a color filter layer by a pre-attached black mask method.
FIG. 19 is a cross-sectional view of another prior art color liquid crystal display device.
[Explanation of symbols]
1 substrate
2 substrate
3 Color filter layer
4 R, G, B color filters
5 Black mask
6 Overcoat layer
7a, 7b Display electrode
8a, 8b alignment film
9 Insulating film
10 Plastic beads
11 Glass beads
12 Sealing material
13 Liquid crystal layer
14 Photosensitive resin material
15 Photomask
16 LCD screen area
17 Backlight
18 Liquid crystal display device
19 Washout

Claims (1)

Attached via a sealant on the outer periphery of the effective display area, filled with liquid crystal between the pair of substrates, and at least one of the pair of substrates absorbs light of a specific wavelength to cause photopolymerization. In a method of manufacturing a liquid crystal display element formed with a color filter layer using a photosensitive resin material ,
Effective display area of the color filter layer made of the photosensitive resin material , or, in the effective display area and a portion of the outer peripheral portion of the effective display area , masking, exposure to light with a specific wavelength from the surface side to adjust the exposure , by firing, to the effective display area of the color filter layer, by increasing the thickness of the effective display area outer periphery whole or part thereof, and the difference in thickness, the effective display a effective display area A method for manufacturing a liquid crystal display element, wherein the thickness of a liquid crystal layer near the entire outer peripheral area or a part thereof is adjusted to be 0.05 to 0.2 μm larger than the thickness of a central part of the effective display area.

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