JP2020042104A - Liquid crystal display - Google Patents

Abstract

To appropriately prevent diffusion, to a display area, of foreign substances generated due to peeling of an alignment film.SOLUTION: The liquid crystal display is a liquid crystal display including a first substrate 51, a second substrate 52, and a liquid crystal layer injected between the first substrate 51 and second substrate 52. The liquid crystal display is provided, on any one of the first substrate 51 and second substrate 52, with a first columnar spacer 11 regulating the distance between the first substrate 51 and second substrate 52, and a ring-shape spacer 12 formed integrally with the first columnar spacer 11 to surround the first columnar spacer 11 and having a lower height than that of the first columnar spacer.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid crystal display device.

  When the distance between a TFT (Thin Film Transistor) substrate and a color filter substrate is defined by a columnar spacer (SP), an alignment film or other film that is peeled off by rubbing with the columnar spacer forms a liquid crystal. The problem of floating as foreign matter is known. Since such a foreign substance causes a bright spot in the liquid crystal, it is required to suppress the generation of the foreign substance.

  Patent Literature 1 discloses a liquid crystal display device that suppresses foreign substances generated by shaving an alignment film or the like from diffusing into a display area.

JP 2010-237506 A

  In Patent Document 1, a weir is formed so as to surround a columnar spacer, and foreign matter is prevented from diffusing into an external region by confining the foreign matter in a region between the spacer and the weir. However, the position of the spacer and the position of the weir change depending on the bonding of the substrates and the dimensional tolerance of the pattern. In this case, according to Patent Literature 1, the spacer may contact the weir depending on the deviation of the dimensional tolerance, and it may not be possible to appropriately prevent the foreign matter from diffusing to the external region.

  Therefore, an object of the present invention is to provide a liquid crystal display device that can appropriately prevent foreign substances generated by peeling of an alignment film or the like into a display region.

  The liquid crystal display device of the present invention is a liquid crystal display device including a first substrate, a second substrate, a liquid crystal layer injected between the first substrate and the second substrate, A first columnar spacer defining a distance between the first substrate and the second substrate on one of the substrate and the second substrate; and a first columnar spacer surrounding the first columnar spacer. A ring-shaped spacer formed integrally with the spacer and having a lower height than the first columnar spacer.

  According to the present invention, it is possible to appropriately prevent foreign matter from diffusing into the display area.

FIG. 1 is a schematic perspective view showing a detailed configuration of the liquid crystal display device according to the present embodiment. FIG. 2 is a diagram illustrating an example of an array of pixels of the display panel of the liquid crystal display device according to the embodiment of the present invention. FIG. 3 is a schematic view illustrating a main columnar spacer of the liquid crystal display device according to the embodiment of the present invention. FIG. 4 is a perspective view showing a main columnar spacer of the liquid crystal display device according to the embodiment of the present invention. FIG. 5 is a diagram for explaining an example of a photomask for forming a main columnar spacer. FIG. 6 is a table showing an example of dimensions of a photomask for forming a main columnar spacer. FIG. 7 is a view for explaining the dimensions of the main columnar spacer of the liquid crystal display device according to the embodiment of the present invention. FIG. 8 is a diagram illustrating a sub columnar spacer of the liquid crystal display device according to the embodiment of the present invention. FIG. 9 is a diagram illustrating a modification of the liquid crystal display device according to the embodiment of the present invention. FIG. 10 is a diagram showing a modification of the liquid crystal display device according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiments, and when there are a plurality of embodiments, a configuration configured by combining the embodiments is also included.

  FIG. 1 is a schematic perspective view showing a detailed configuration of the display device according to the present embodiment. In the following description, an XYZ rectangular coordinate system is set, and the positional relationship between the components will be described with reference to the XYZ rectangular coordinate system. The X axis, the Y axis, and the Z axis are orthogonal to each other. In the present disclosure, the X-axis direction corresponds to a “first direction”, the Y-axis direction corresponds to a “second direction”, and the Z-axis direction corresponds to a “third direction”. Further, in the present disclosure, viewing the XY plane including the X axis and the Y axis from the Z axis direction corresponds to “plan view”.

  In the example shown in FIG. 1, the liquid crystal display device 100 has two sides extending in the X-axis direction (first direction) and two sides extending in the Y-axis direction (second direction). The liquid crystal display device 100 includes a display panel 5 and a backlight (illumination device) 6 that illuminates the display panel 5, and the display panel 5 and the backlight 6 are stacked in the Z-axis direction (third direction). I have.

  Note that the liquid crystal display device 100 may have a rectangular shape in XY plane view. In the present embodiment, the rectangle includes a rounded rectangle. In other words, at the four corners, each side does not cross, but includes a square having a curved shape. For example, it may be rectangular in XY plan view, or at least one of the corners may have a curvature. Further alternatively, the liquid crystal display device 100 may have a shape other than a rectangular shape in XY plane view.

  The display panel 5 has a display area provided in parallel with the XY plane, and a peripheral area provided on the outer periphery of the display area. The display of the display area can be confirmed by the observer from the Z-axis direction (third direction).

  The backlight 6 irradiates light from at least the display area from the back of the display panel 5.

  The backlight 6 has one end in the X-axis direction (first direction) and one end in the Y-axis direction (second direction) with respect to a light guide plate (not shown) provided at a position corresponding to the display area in XY plane view. Alternatively, a so-called sidelight type backlight having a plurality of light sources (for example, light emitting diodes (LEDs: Light Emitting Diodes) emitting white light) arranged at both ends may be used. Further, the backlight 6 may be a so-called direct type backlight having a light source (for example, an LED that emits white light) provided immediately below the display area in the XY plane view. The power supply to the light source of the backlight 6 and the control signal are supplied from the display panel 5.

  The backlight 6 and the display panel 5 are attached to each other via, for example, an adhesive tape. The adhesive tape is preferably, for example, a translucent double-sided pressure-sensitive adhesive sheet (OCA: Optical Clear Adhesive).

  As shown in FIG. 1, the display panel 5 includes a TFT substrate 51, a color filter substrate 52 disposed to face the TFT substrate 51, a first polarizing plate 53, a second polarizing plate 55, a driver IC 59, and an FPC. (Flexible Printed Circuit) substrate 9.

  In the example shown in FIG. 1, the display panel 5 has a second polarizing plate 55, a TFT substrate 51, a color filter substrate 52, and a first polarizing plate 53 in the Z-axis direction (third direction) from the backlight 6 side. Are laminated. In the present disclosure, the TFT substrate 51 corresponds to a “first substrate”, and the color filter substrate 52 corresponds to a “second substrate”.

  The color filter substrate 52 and the TFT substrate 51 are bases made of a light-transmitting glass or the like. The TFT substrate 51 has a thin film transistor (TFT) element formed on a base. The color filter substrate 52 is provided with a color filter, a light shielding layer, and the like. A liquid crystal layer is injected between the TFT substrate 51 and the color filter substrate 52.

  The area of the TFT substrate 51 is larger than that of the color filter substrate 52 in XY plane view. The TFT substrate 51 and the color filter substrate 52 are bonded together with one side of the TFT substrate 51 extending in the X-axis direction (first direction) projecting from the color filter substrate 52. The TFT substrate 51 has a plurality of pixel electrodes arranged in a matrix and a common electrode formed insulated from the pixel electrodes. On the TFT substrate 51, wiring such as a pixel signal line for supplying a pixel signal to a pixel electrode and a scanning signal line for driving each TFT element is formed via the TFT element. Note that the common electrode may not be provided on the TFT substrate 51, and the common electrode may be provided on the color filter substrate 52.

  Specifically, in the example shown in FIG. 1, the size of the TFT substrate 51 in the X-axis direction (first direction) is equal to the size of the color filter substrate 52 in the X-axis direction (first direction). The size in the Y-axis direction (second direction) is larger than the size of the color filter substrate 52 in the X-axis direction (first direction).

  As shown in FIG. 1, two sides of the TFT substrate 51 in the X-axis direction (first direction) and two sides of both ends of the color filter substrate 52 in the X-axis direction (first direction) respectively overlap. One side of one end of the TFT substrate 51 in the Y-axis direction (second direction) overlaps one side of one end of the color filter substrate 52 in the Y-axis direction (second direction). Then, one side of the other end in the Y-axis direction (second direction) of the TFT substrate 51 and one side of the other end in the Y-axis direction (second direction) of the color filter substrate 52 are bonded to each other.

  In the XY plane view, in a region other than the overhang portion 51a of the TFT substrate 51 overhanging from the color filter substrate 52, the TFT substrate 51 and the color filter substrate 52 overlap in the Z-axis direction (third direction). Thereby, the end face of the outer peripheral end of the display panel 5 in the XY plane view matches the end face of the outer peripheral end of the TFT substrate 51 in the XY plane view.

  An example of an array of pixels of the display panel of the liquid crystal display device according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of an array of pixels of the display panel of the liquid crystal display device according to the embodiment of the present invention.

  As shown in FIG. 2, in the display area of the display panel 5 of the present embodiment, blue pixels 61B, red pixels 61R, and green pixels 61G are sequentially arranged at predetermined intervals in the horizontal direction. In the vertical direction, pixels of the same color are arranged at predetermined intervals.

  In the present embodiment, the main column spacer 10 and the sub column spacer 70 are arranged on the black matrix 60 between pixels in the vertical direction. As will be specifically described later, the main columnar spacer 10 defines a distance between the TFT substrate 51 and the color filter substrate 52. The sub columnar spacers 70 are columnar spacers that are lower in height than the main columnar spacers 10, and are arranged in a greater number than the main columnar spacers 10.

  The layout configuration of the main columnar spacers 10 and the sub columnar spacers 70 shown in FIG. 2 is an example, and does not limit the present invention. The layout configuration of the main columnar spacer 10 and the sub columnar spacer 70 can be arbitrarily changed. Specifically, the main columnar spacer 10 has a large diameter by the provision of the ring-shaped spacer 12, and therefore, if many are arranged, the transmittance of the liquid crystal panel is reduced. Therefore, for example, the arrangement position of the main columnar spacer 10 may be determined in consideration of the transmittance of the liquid crystal panel and the like, and the sub columnar spacer 70 may be arranged at the remaining position.

  The main columnar spacer 10 will be described with reference to FIG. As shown in FIG. 3, the main columnar spacer 10 of the liquid crystal display according to the embodiment of the present invention includes a first columnar spacer 11 and a ring-shaped spacer 12. In FIG. 3, thin components directly related to the present invention are not shown.

  The first columnar spacer 11 is formed on, for example, a color filter substrate 52, and defines a distance between the TFT substrate 51 and the color filter substrate 52. As shown in FIG. 3, the apex of the first columnar spacer 11 is in contact with the alignment film 40 formed on the TFT substrate 51. The alignment film 40 in contact with the first columnar spacer 11 has a planar shape. Here, the planar shape includes an uneven shape caused by a thin film transistor or the like included in the TFT substrate 51. Since the structure of the contact portion of the first columnar spacer 11 has a planar shape, a variation in each product when the TFT substrate 51 and the color filter substrate 52 are bonded to each other is reduced. Thus, in the present embodiment, the TFT substrate 51 and the color filter substrate 52 can be accurately bonded to each other, so that, for example, the light shielding area can be reduced. In FIG. 3, the first columnar spacer 11 is formed on the color filter substrate 52, but this is an example and does not limit the present invention. The first columnar spacer 11 may be formed, for example, on the TFT substrate 51 side. That is, in the present embodiment, the first columnar spacer 11 may be formed on either the TFT substrate 51 or the color filter substrate 52.

  The ring-shaped spacer 12 is a ring-shaped spacer formed integrally with the first columnar spacer 11 so as to surround the first columnar spacer 11 and having a lower height than the first columnar spacer 11. Although not clear in FIG. 3, the ring-shaped spacer 12 is formed so as to surround the first columnar spacer 11, as shown in FIG.

  A groove 13 is formed in a region between the first columnar spacer 11 and the ring-shaped spacer 12. For this reason, foreign matter such as shavings of the alignment film 40 generated from the contact portion between the first columnar spacer 11 and the alignment film 40 is accumulated in the region A of the groove 13. That is, the present embodiment prevents foreign substances from diffusing into the display area by storing foreign substances in the area A of the groove 13 between the first columnar spacer 11 and the ring-shaped spacer 12. In the present embodiment, the size of the foreign matter is, for example, about 1 to 10 μm, but is not limited thereto.

  A method of integrally forming the first columnar spacer 11 and the ring-shaped spacer 12 will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram illustrating an example of a photomask pattern for integrally forming the first columnar spacer 11 and the ring-shaped spacer 12. FIG. 6 is a table showing an example of the dimensions of the photomask pattern.

  FIG. 5 shows an example of a photomask pattern for integrally forming the first columnar spacer 11 and the ring-shaped spacer 12. As shown in FIG. 5, the photomask pattern 90 has a first region 91, a second region 92, and a third region 93.

  The first region 91 is a region used for forming the first columnar spacer 11. For this reason, the first region 91 is a region having the highest transmittance in the photomask pattern 90. As shown in FIG. 6, the width d1 of the first region 91 is, for example, 10 to 16 μm. In particular, the width d1 of the first region 91 is optimally 13 μm. It should be noted that the dimensions shown in FIG. 6 are merely examples and do not limit the present invention.

  The second region 92 is a region used for forming the groove 13. Therefore, the second region 92 is a region having the lowest transmittance in the photomask pattern 90. The distance d2 from one end to the other end of the second region 92 is, for example, 18 to 28 μm as shown in FIG. In particular, the distance d2 from one end to the other end of the second region 92 is optimally 23 μm. It should be noted that the dimensions shown in FIG. 6 are merely examples and do not limit the present invention.

  The third region 93 is a region used for forming the ring-shaped spacer 12, and is made of a halftone mask. For this reason, the third region 93 has a transmittance between the first region 91 and the second region 92 in the photomask pattern 90. The distance d3 from one end to the other end of the third region 93 is, for example, 28 to 38 μm as shown in FIG. In particular, the distance d3 from one end to the other end of the third region 93 is optimally 33 μm. It should be noted that the dimensions shown in FIG. 6 are merely examples and do not limit the present invention.

  In the present embodiment, a portion corresponding to the first columnar spacer 11 is exposed to the photoresist in the first region 91, a portion corresponding to the groove 13 is exposed to the second region 92, and the photoresist corresponds to the ring-shaped spacer 12. The portion is exposed in the third region 93 and developed. Then, by removing the unnecessary photoresist, the first columnar spacer 11 and the ring-shaped spacer 12 can be integrally formed. That is, in the present embodiment, the first columnar spacer 11 and the ring-shaped spacer 12 are formed of a single member.

  The dimensions of the first columnar spacer 11 and the ring-shaped spacers and 12 will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining an example of the dimensions of the first columnar spacer 11 and the ring-shaped spacer 12.

  The height L1 of the first columnar spacer 11 is formed to be, for example, about 2.4 to 2.8 μm. The height L2 of the ring-shaped spacer 12 is, for example, about 2.2 to 2.5 μm. The depth L3 from the ring-shaped spacer 12 to the groove 13 is, for example, about 0.2 to 2.5 μm. The step L4 between the first columnar spacer 11 and the ring-shaped spacer 12 is formed to be, for example, about 0.2 to 0.6 μm. It should be noted that the dimensions of these parts are merely examples, and do not limit the present invention. Specifically, the dimensions of each part may be larger or smaller than the above-described values.

  The main columnar spacer 10 has a shape in which a ring-shaped spacer 12 having a height of, for example, about 0.2 to 0.6 μm is formed around the first columnar spacer 11. Here, since the first columnar spacer 11 and the ring-shaped spacer 12 are integrally formed, the position of the first columnar spacer 11 is always constant in relation to the ring-shaped spacer 12. Therefore, the possibility of contact between the first columnar spacer 11 and the ring-shaped spacer 12 can be reduced. Further, in the present embodiment, the portion facing the first columnar spacer 11 has a flat shape, so that a change in the cell gap due to the displacement of the bonding between the TFT substrate 51 and the color filter substrate 52 is prevented.

  In the main columnar spacer 10, the ring-shaped spacer 12 is formed by a halftone mask. Therefore, in the present embodiment, the height of the ring-shaped spacer 12 can be freely changed by adjusting the exposure rate of the halftone mask. That is, the step L4 between the first columnar spacer 11 and the ring-shaped spacer 12 can be set freely. Thus, in the present embodiment, it is possible to optimally set the step L4 between the first columnar spacer 11 and the ring-shaped spacer 12, for example, according to the size of the foreign matter.

  As described above, in the main columnar spacer 10, the ring-shaped spacer 12 is formed using a halftone mask. Therefore, in the present embodiment, the depth L3 from the top of the ring-shaped spacer 12 to the bottom of the groove 13 can be freely changed by adjusting the exposure rate of the halftone mask. Thus, in the present embodiment, for example, the depth L3 from the ring-shaped spacer 12 to the groove 13 can be optimally set according to the size of the foreign matter.

  In addition, the main columnar spacer 10 of the present embodiment can be created using existing equipment. Therefore, the present embodiment is also advantageous from the viewpoint of cost.

  In the present embodiment, a step is provided between the first columnar spacer 11 and the ring-shaped spacer 12. For this reason, when the step between the first columnar spacer 11 and the ring-shaped spacer 12 is set wide, the possibility of contact with the components of the TFT substrate 51 is reduced. It can be arranged close to the columnar spacer 10. As a result, in the present embodiment, the degree of freedom in product design can be improved.

  Next, the sub columnar spacer 70 will be described with reference to FIG. FIG. 8 is a schematic view showing the sub columnar spacer 70.

  As shown in FIG. 8, the sub columnar spacer 70 includes a second columnar spacer 71 that is lower in height than the first columnar spacer 11 of the main columnar spacer 10. Specifically, the height of the second columnar spacer 71 is lower than that of the first columnar spacer 11 by about 0.3 to 0.4 μm. Thus, the second columnar spacer 71 prevents the first columnar spacer 11 of the main columnar spacer 10 from being crushed when a force is applied to the opposing substrate. Such a second columnar spacer 71 can be formed by, for example, a halftone mask. That is, the height of the second columnar spacer 71 can be adjusted by adjusting the exposure rate of the halftone mask.

  The sub columnar spacer 70 does not include a ring spacer formed integrally with the second columnar spacer 71. This is because the height L5 of the second columnar spacer 71 is lower than the height L1 of the first columnar spacer 11 of the main columnar spacer 10. Specifically, the second columnar spacer 71 does not come into contact with the alignment film 40 of the opposing substrate and does not generate foreign matter by cutting the alignment film or the like. This is because there is no need to form a ring-shaped spacer. In other words, in the present embodiment, the ring-shaped spacer is formed only around the columnar spacer that may cause foreign matter by shaving the alignment film.

  Here, the height of the sub-columnar spacer 70 may be the same as or different from the height of the ring-shaped spacer 12. The relationship between the height of the sub-columnar spacer 70 and the height of the ring-shaped spacer 12 may be arbitrarily changed according to the design.

  As described above, the present embodiment includes the first columnar spacer 11 and the ring-shaped spacer 12 formed integrally with the first columnar spacer 11 so as to surround the first columnar spacer 11. As a result, in the present embodiment, foreign substances can be stored in the groove 13 between the first columnar spacer 11 and the ring-shaped spacer 12, so that the foreign substances generated by the peeling of the alignment film and the like can be deposited on the display area. Diffusion can be appropriately prevented.

  In the present embodiment, the step between the top of the first columnar spacer 11 and the top of the ring-shaped spacer 12 can be appropriately changed according to the size of the foreign matter. As a result, in the present embodiment, it is possible to more appropriately prevent foreign substances generated by peeling of the alignment film and the like into the display region.

  Further, in the present embodiment, the depth from the apex of the ring-shaped spacer 12 to the bottom of the groove 13 can be appropriately changed according to the size of the foreign matter. As a result, in the present embodiment, it is possible to more appropriately prevent foreign substances generated by peeling of the alignment film and the like into the display region.

  In the present embodiment, among the columnar spacers arranged on the black matrix 60, the ring-shaped spacer is formed only around the columnar spacer reaching the alignment film of the opposing substrate. As a result, in the present embodiment, it is possible to more appropriately prevent foreign substances generated by peeling of the alignment film and the like into the display region.

[Modification]
A modified example of the embodiment of the present invention will be described with reference to FIG. FIG. 9 is a schematic diagram illustrating a configuration of a modification according to the embodiment of the present invention.

  As shown in FIG. 9, the modification of the embodiment is different from the liquid crystal display device 1 in that a ring-shaped projection 80 is provided on a surface of the main columnar spacer 10 facing the groove 13.

  In the example shown in FIG. 9, the movement of the foreign matter stored in the groove 13 is restricted by the ring-shaped protrusion 80. That is, in the example shown in FIG. 9, the foreign matter accumulated in the groove 13 is hardly diffused outside due to the ring-shaped convex portion 80, and the moving distance required for diffusing outside is increased. As a result, in the modification of the present embodiment, it is possible to more appropriately prevent foreign substances generated by peeling of the alignment film 40 and the like from diffusing into the display area.

  Another modification of the embodiment of the present invention will be described with reference to FIG. FIG. 10 is a schematic diagram illustrating a configuration of another modification according to the embodiment of the present invention.

  As shown in FIG. 10, in another modification of the embodiment, a ring-shaped protrusion 80 may be provided on the outer periphery of the ring-shaped spacer 12. Even in this case, the foreign matters accumulated in the groove 13 are less likely to diffuse outside due to the ring-shaped convex portion 80, and the movement distance required for diffusing the foreign matter increases. As a result, in the modification of the present embodiment, it is possible to more appropriately prevent foreign substances generated by peeling of the alignment film 40 and the like from diffusing into the display area.

  The embodiment is not limited by the contents described above. The components of the above-described embodiments include those easily conceivable by those skilled in the art, those that are substantially the same, and those that are in an equivalent range. Furthermore, various omissions, substitutions, and changes of the components can be made without departing from the spirit of the above-described embodiment.

5 Display panel 6 Backlight (lighting device)
DESCRIPTION OF SYMBOLS 10 Main columnar spacer 11 1st columnar spacer 12 Ring-shaped spacer 13 Groove 40 Alignment film 51 TFT substrate (1st substrate)
52 color filter substrate (second substrate)
53 First polarizing plate 55 Second polarizing plate 60 Black matrix 61B Blue pixel 61R Red pixel 61G Green pixel 70 Sub-columnar spacer 71 Second columnar spacer 80 Convex part 90 Photomask pattern 91 First region 92 Second region 93 Third region 100 liquid crystal display

Claims (8)

A liquid crystal display device including a first substrate, a second substrate, a liquid crystal layer injected between the first substrate, and the second substrate,
The first substrate and one of the second substrates,
A first columnar spacer that defines a distance between the first substrate and the second substrate;
A ring-shaped spacer integrally formed with the first columnar spacer so as to surround the first columnar spacer, and having a lower height than the first columnar spacer.
Liquid crystal display. The first columnar spacer and the ring-shaped spacer are formed by a single member,
The liquid crystal display device according to claim 1. The first columnar spacer is opposed to the alignment film;
The liquid crystal display device according to claim 1. A portion facing the first columnar spacer has a planar shape.
The liquid crystal display device according to claim 1. The difference between the apex of the first columnar spacer and the apex of the ring-shaped spacer is defined according to the size of foreign matter existing between the first columnar spacer and the ring-shaped spacer.
The liquid crystal display device according to claim 1. The depth from the top of the ring-shaped spacer to the bottom of the groove between the first columnar spacer and the ring-shaped spacer is less than that of the foreign matter existing between the first columnar spacer and the ring-shaped spacer. Stipulated according to the size,
The liquid crystal display device according to claim 1. A second columnar spacer having a height lower than the first columnar spacer;
The ring-shaped spacer is formed only around the first columnar spacer,
The liquid crystal display device according to claim 1. The first columnar spacer further includes a ring-shaped convex portion in at least one of a region facing between the ring-shaped spacer and a region facing near an external region of the ring-shaped spacer,
The liquid crystal display device according to claim 1.

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