WO2023003207A1 - Light guide plate using grouping pattern and display device comprising same - Google Patents

Abstract

The present invention relates to a light guide plate using a grouping pattern and a display device comprising same, wherein: the light guide plate has a plurality of dot patterns provided on one surface thereof, for diffusing a light source; the plurality of dot patterns are clustered to form a group pattern; the group pattern is provided in a plurality in the horizontal and vertical directions with respect to the light incident surface; and the plurality of group patterns are arranged in at least one of a precision array, in which the group patterns are evenly spaced in the horizontal direction and in the vertical direction, and a random array, in which the group patterns are randomly spaced, such that the visibility of defects due to impurities is minimized, giving a uniform, high-quality appearance to a liquid crystal display, and defects during mass production of large light guide plates are minimized, thereby improving the quality and productivity of a display.

Description

Light guide plate using grouping pattern and display device including the same

The present invention relates to a light guide plate using a grouping pattern and a display device including the same, and more particularly, to a technique for minimizing the visibility of defects in the light guide plate to the human eye.

As the technology of modern society is advanced, display devices commonly seen in daily life face market demands for larger and thinner displays.

As conventional CRT (Cathode-ray tube) devices do not sufficiently satisfy these demands, PDP (Plasma Display Panel) devices, LCD (Liquid Crystal Display) devices, OLED (Organic Light-Emitting Diode) devices, etc. Demand for a representative flat panel display device is explosively increasing.

A liquid crystal display (LCD) is one of the most widely used flat panel displays (FPD), and consists of two substrates on which electrodes are formed and a liquid crystal layer inserted therebetween. It is a device that displays an image by adjusting the amount of transmitted light by rearranging the liquid crystal molecules of the liquid crystal layer by applying a .

In general, a display such as a liquid crystal display (LCD) uses a two-dimensional light source that transmits light emitted from a one-dimensional light source to a light guide plate and then transmits through one surface thereof. At this time, the efficiency of the surface light source is the overall efficiency of the display device. It is emerging as an important factor in determining performance.

The efficiency of light in a conventional liquid crystal display (LCD) is about 3 to 10%, and light loss mainly occurs in a light guide plate, a polarizer, and a color filter.

Therefore, displays are being developed in a direction capable of reducing manufacturing costs while minimizing the loss of light.

However, there is a tendency for diffusion sheets, prism sheets, and DBEF (Dual Brightness Enhancement Film) sheets installed on the light guide plate to be integrated or detached. Accordingly, the visibility of the crystals in the light guide plate is gradually increasing.

As the pattern formation method of the light guide plate has changed to the roll stamping method, the size of the pattern is formed very finely in preparation for defects, and the vulnerability of the light guide plate to defects has increased.

The visibility of such excessive defects may increase the defect rate of the light guide plate, reduce the efficiency of the assembly process, and deteriorate the image quality of the display.

A conventional backlight device may include a light guide plate, a reflective sheet installed under the light guide plate, a QD sheet installed above the light guide plate, a diffusion sheet, a prism sheet, a DBED sheet, and a light source installed on one side of the light guide plate.

Here, the light guide plate is made of PMMA (Poly Methylmethacrylate), MS (Methylmethacrlate Styrens), PS (Poly Styrene), PC (Poly Carbonate), PET (polyethylene terephthalate), etc. It can be made of the same plastic or resin.

In addition, the light guide plate includes a pattern of a predetermined shape on one side of the inside. In the pattern, a plurality of circular, elliptical, and vertical bar patterns are formed at regular or random intervals in the horizontal and vertical directions of light emitted from an external light source.

After the light emitted from the external light source is incident on the light guide plate, a part of it is emitted to the outside of the light guide plate by the pattern, but some defects play a role similar to the pattern and are likewise emitted to the outside. A part of the light emitted by the defect is emitted as light having a higher intensity than the pattern, so that a light non-uniformity region that is noticeable in a backlight requiring a uniform surface light source as a whole can be visually recognized.

Due to this, the prior art has a problem in that a partial area of the liquid crystal screen is brightened due to a non-uniformity phenomenon generated from the defect, so that the overall appearance is not uniform.

[Prior art literature]

[Patent Literature]

(Patent Document 1) Republic of Korea Patent Registration No. 10-1158524 (2012.06.21.)

The present invention can provide a light guide plate using a grouping pattern capable of minimizing non-uniform visibility formed as defects by densely controlling existing patterns formed on the light guide plate and a display device including the same.

A light guide plate using a grouping pattern according to one aspect of the present invention includes a plurality of dot patterns for dispersing light sources on one side of the light guide plate, wherein a plurality of the dot patterns are densely clustered to form a group pattern, and the group pattern is formed on a light incident surface. A plurality of groups are formed in the transverse and longitudinal directions based on, and the plurality of group patterns are formed at equal intervals in the transverse and longitudinal directions, and at least one of a precise array formed at regular intervals and a random array formed at random intervals. can

Preferably, at least one of the dot pattern and the group pattern may be provided by changing the distribution density for each position.

Preferably, the group pattern may be formed in a zigzag pattern in a transverse direction based on the side surface.

Preferably, the group patterns may be arranged at different intervals between at least one pair of group patterns in the longitudinal direction.

Preferably, a display device including the light guide plate may be provided.

According to the present invention, by adjusting the pattern formed on the light guide plate, it is possible to provide a uniform and high-quality appearance to the liquid crystal screen by minimizing non-uniform light viewing caused by defects in the light guide plate.

In addition, when mass-producing large-sized displays and light guide plates, the quality and productivity of displays can be improved.

1 is a configuration diagram illustrating a light guide plate using a grouping pattern according to an exemplary embodiment.

2 is a schematic diagram illustrating dispersion of light according to grouped patterns according to an exemplary embodiment.

3 is a detailed schematic diagram of a light guide plate showing precision arrangement according to an exemplary embodiment.

4 is a detailed schematic diagram of a light guide plate showing a random arrangement according to an exemplary embodiment.

5 is a detailed schematic view of a light guide plate showing precise arrangement and random arrangement according to an embodiment.

6 is a diagram illustrating an external state of a light guide plate to which a group pattern arrangement structure according to an exemplary embodiment is applied.

Hereinafter, a light guide plate using a grouping pattern according to the present invention and a display device including the same will be described in detail with reference to the accompanying drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to an operator's intention or practice. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

The objects and effects of the present invention can be naturally understood or more clearly understood by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

1 is a configuration diagram illustrating a light guide plate using a grouping pattern according to an exemplary embodiment.

As shown in FIG. 1 , a light guide plate using a grouping pattern according to an embodiment includes a plurality of dot patterns 10 dispersing light sources 30 on one side of the light guide plate 100, but the dot patterns 10 are A plurality of group patterns 20 are formed by densely forming a plurality of group patterns 20 in the transverse and longitudinal directions based on the light incident surface, and the plurality of group patterns 20 are formed in the transverse and longitudinal directions It may be provided with at least one arrangement of a precise arrangement formed at equal intervals and a random arrangement formed at random intervals.

Here, at least one of the dot pattern 10 and the group pattern 20 may be provided by changing the distribution density for each position, and the group pattern 20 may be formed in a zigzag pattern in the transverse direction based on the side surface, The group patterns may be disposed differently from each other at mutual intervals between at least one pair of group patterns in the longitudinal direction. That is, at least one pair of group patterns among each of the group patterns formed in the longitudinal direction with respect to the light source may have different intervals.

Here, as for the distribution density of the group patterns, the closer the light source is, the farther the distance from each group pattern is, and the farther away from the light source, the narrower the distance between each group pattern can be.

In addition, the group pattern 20 may be arranged at a predetermined angle so as to secure an optical path with respect to the plane on which the light source 30 is incident.

The dot pattern 10 may be provided in various forms to disperse the light source 30 incident from the side to the front, and is formed by a printing method, an injection method, an imprinting method, a laser processing method, a V-cutting method, or a stamp method. However, it is not necessarily limited to the above method.

At this time, the dot pattern 10 may be changed in any one of a triangular, square, bar, elliptical, circular, donut, cylindrical, curved, and oblique shape, but the dot pattern 10 The form is not necessarily limited to the above-mentioned form.

The shape of the dot pattern 10 can be changed as needed, and methods for changing the shape include mechanical processing, laser processing, sanding processing, injection molding, press molding, extrusion molding, stamp molding, pressure molding, and water jet molding methods. It is not necessarily limited to the above-mentioned shape change method.

In addition, the group pattern 20 in which the dot patterns 10 are densely packed may be transformed into a square, a rhombus, a circle, an ellipse, a triangle, or a bar shape according to the arrangement of the dot patterns 10, but it is necessarily limited to the above-described shapes. it is not going to be

Here, the light guide plate is made of PMMA (Poly Methylmethacrylate), MS (Methylmethacrlate Styrens), PS (Poly Styrene), PC (Poly Carbonate), PET (polyethylene terephthalate), etc. It can be formed of plastic or resin.

The key to the light guide plate 100 is to receive light from the side and emit light to the front to uniformly distribute the light over the entire area. If light is directly emitted from a general surface light emitting or surface light source, it is highly likely to be recognized as defects (A1) and scratches (A2) due to impurities generated during the process due to the straightness of light, so these defects (A1) and scratches ( A dot pattern 10 may be formed on the bottom surface of the light guide plate 100 to disperse the light source 30 in order to lower the visibility of A2).

The light source 30 of FIGS. 1 to 5 shows the position of the light source 30 arranged at the X-Pitch to explain one embodiment, but the position of the light source is not limited to one embodiment. That is, the light source 30 is not necessarily arranged limited to the X-Pitch. For example, the light source 30 may be disposed at at least one of an X-Pitch and a Y-Pitch. This enables the amount of light emitted from the light guide plate to be adjusted to the front surface according to the number and position of the light sources 30 located on each side.

The formed dot pattern 10 may be formed in a size of 30 to 70 μm, and serves to refract the light source 30 incident from the side and disperse it in various angles.

However, before the light source 30 incident from the side is refracted through the dot patterns 10 uniformly distributed throughout the light guide plate 100 and emitted to the front, the refracted light source 30 moves to the side of the light guide plate 100. It is likely to be released and act as a loss. In addition, the direction of refraction of the light source 30 when emitting from a dense medium to a sparse medium and the direction of refraction when emitting from a dense medium to a sparse medium are different. The distributed dot pattern 10 is not emitted when the light source 30 advances at a specific angle and reaches the front surface, and is totally reflected, which may lead to light loss.

That is, when the angle at which the light source 30 is incident on the front surface becomes larger than a predetermined value, the light after the critical angle does not refract or transmit, but causes total reflection, resulting in disappearance inside the light guide plate 100.

Accordingly, as the number of light sources 30 dispersed at a specific location is further increased by densely concentrating a plurality of the dot patterns 10 , the light sources 30 can be emitted at various angles.

2 is a schematic diagram illustrating dispersion of light according to grouped patterns according to an exemplary embodiment.

As shown in FIG. 2 , in the dispersion of light according to the grouped patterns according to an embodiment, as the density of the dot pattern 10 increases, the visibility of defects A1 and scratches A2 decreases.

The following [Table 1] shows the visibility of the defect A1 according to adjusting the density of the dot pattern 10. As shown in Table 1, it can be confirmed that as the density of the dot pattern 10 increases, the degree of visibility of defects A1 and scratches A2 generated during the process decreases.

number of patterns	One	2	3	4	5	6	7	8	9	10
number of defects	5	4	4	4	3	3	3	2	2	2
number of patterns	11	12	13	14	15	16	17	18	19	20
number of defects	2	2	2	2	One	One	One	One	One	One

In [Table 1], the number of patterns is the number of dense dot patterns 10. Here, as the number of patterns increases, an inverse relationship in which the number of defects (A1) decreases appears, and from 8 or more grouped patterns, it can be seen that the number of defects (A1), which was 5, appears to be 2 or less. When the number of defects (A1) is lowered to 2 or less, good quality conditions can be satisfied.

Therefore, even if the defect A1 occurs during the process, it is possible to produce a product that satisfies the quality condition, and productivity can be greatly improved by reducing the defect rate.

[Correction under Rule 91 08.08.2022]
The plurality of dot patterns 10 in each group pattern 20 may be formed at regular or random intervals. As shown in FIG. 7, the visibility of the defect A1 may vary according to the shape of each group pattern 20.

[Correction under Rule 91 08.08.2022]

[Correction under Rule 91 08.08.2022]
7 shows the visibility level and light efficiency of a defect A1 of a group pattern 20 in which a plurality of dot patterns 10 are densely packed.

[Correction under Rule 91 08.08.2022]
As shown in FIG. 7, it can be seen that the number of defects A1, which was 5 in the dot pattern, decreased from 6 to 2 in the group pattern. The number of dot patterns 10 of the group pattern 6 is 16. Thereafter, it can be confirmed that the degree of visibility of the defect A1 is reduced from the group pattern 7 to the group pattern 10. That is, it can be seen that there is no significant difference in the degree of visibility of the defect A1 by the pattern, and the number of patterns greatly affects it.

The probability of light emitted from the light source 30 escaping to the front increases as the number of patterns of the group patterns 20 increases. This means that the degree of brightness per group pattern 20 increases, and conversely, the degree of visibility of the defect A1 may decrease.

In addition, the group pattern 8 is a bar-shaped dot pattern 10 densely packed, and it can be seen that the light efficiency of 102.1% exceeds the light efficiency of 100% of the existing pattern.

The reason for this phenomenon is that when the light from the light source 30 is dispersed in various angles and emitted to the front of the light guide plate 100, the bar-shaped group patterns 20 densely perpendicular to the light source 30 are formed for each pattern. This is because it maximizes the efficiency of light. Conversely, in group patterns 4, 5, 7, and 8, light loss, that is, reduction in light efficiency, occurred when some light sources 30 could not escape to the front surface in the process of dispersing the light sources 30 from the dot pattern 10 in dense patterns with a certain interval or more. can be checked with

Next, problems in appearance according to the arrangement structure of each row group of the plurality of group patterns 20 can be confirmed.

[Correction under Rule 91 08.08.2022]

division	Density Array				Delta array			Density+Delta array
	One	2	3	4	5	6	7	8	9	10
X-pitch × Ratio (%)	50	50	75	75	50	50	75	50	50	75
Y-pitch × Ratio (%)	0	30	30	50	0	30	30	0	30	30
appearance level	2	One	2	3	One	2	3	One	One	One

The arrangement structure is a group pattern ( 20) can be spaced apart at regular intervals, and the appearance state can be confirmed by changing the shape of the arrangement. Depending on the arrangement of the group patterns 20, the appearance state may appear as light spreading or light bias due to dispersion of light, and in some cases, a Moire phenomenon may appear. In addition, the larger the size of the light guide plate and the shape size of the group pattern 20, the more the problem of this phenomenon can be highlighted.

This phenomenon is caused by the difference between the area where the light sources 30 scattered in the group pattern 20 reach the front and the area where the overlapping light sources 30 are relatively large and small, and the difference between the group pattern 20 or the dot pattern 10. Even a regular arrangement or the like can cause problems.

In order to prevent this, the problem of appearance can be solved by changing and applying the arrangement structure of the group pattern 20 for each row direction. That is, when the plurality of dot patterns 10 are arranged in a specific arrangement structure in a row direction, light distribution according to the arrangement structure of the group patterns 20 can be confirmed by the light sources 30 reaching the front surface.

[Correction under Rule 91 08.08.2022]
As in [Table 2], the Density array is specified as a random array, and the Delta array is specified as a precision array.

3 and 4 are detailed schematic diagrams of a light guide plate showing arrangement structures of precision arrangement and random arrangement according to an embodiment.

As shown in FIGS. 3 and 4 , the arrangement structure of the group patterns 20 according to an exemplary embodiment may include at least one of a precise arrangement and a random arrangement. Here, in the precise arrangement, the group patterns 20 may be formed at regular intervals, and in the random arrangement, the group patterns 20 may be formed at random intervals.

At this time, in the case of the group patterns 20 arranged in precise arrangement, it refers to an arrangement designed at equal intervals in at least one direction of X-pitch and Y-pitch, and patterns are formed according to regular intervals to confirm stable light distribution. On the other hand, the moiré phenomenon may appear conspicuously. As shown in Table 3, by randomly arranging X-pitch or Y-pitch array intervals in a precise array structure, it is possible to minimize and solve the moiré phenomenon.

In the case of the group patterns 20 arranged in a random arrangement, the degree of dispersion of the light source 30 is not constant compared to the case where the spacing between the group patterns 20 is constant, so a moiré phenomenon that may occur in a structure having a uniform pattern density. problems can be minimized.

However, depending on the degree of dispersion, it may appear as a mottled appearance, and as shown in Table 3, the problem can be minimized and solved by adjusting the ratio of the X-pitch and Y-pitch of the random array.

In addition, precise array and random array can be arranged at the same time. If the precise array and the random array are arranged at the same time, the above-described problems of the precise array and the random array can be supplemented at the same time. However, in order to solve the above-mentioned problem, it is not necessarily necessary to apply precise array and random array at the same time. Precise arrangement and random arrangement represent arrangement methods according to respective embodiments, and it should be recognized that the light guide plate 100 using only precision arrangement and the light guide plate 100 using only random arrangement may be used in some cases.

5 is a detailed schematic view of a light guide plate in which precision arrangement and random arrangement are arranged according to an embodiment.

As shown in FIG. 5 , in the light guide plate 100 in which the precise arrangement and the random arrangement are arranged according to an embodiment, a group pattern 20 is disposed by grouping the first row and the second row into a first row group 41 . can

At this time, the group patterns 20 of the first row arranged horizontally with respect to the Y-pitch are arranged at regular intervals, and the group patterns 20 of the second row are a pair of group patterns of the first row ( 20) The group patterns 20 of the first row and the second row may be arranged in a zigzag form by being arranged between positions.

Thereafter, the third row and the fourth row may also be grouped into the second row group 42, and the group patterns 20 may be arranged at regular intervals in a precise arrangement.

Here, the group pattern 20 of the third row may be disposed between the pair of group patterns 20 of the second row, and the group pattern 20 of the fourth row may be disposed between the pair of group patterns 20 of the third row. (20) may be arranged in a zigzag form.

That is, the first row group 41 that binds the first row and the second row and the second row group 42 that binds the third row and fourth row are precision arrangements for each row group 40, Groups 40 may be arranged randomly. Here, the precise array and the random array may be applied and provided to each row group. However, the above-described precision arrangement and random arrangement are for explanation of an embodiment and are not necessarily limited to the first row group and the second row group.

Therefore, it is possible to simultaneously solve the difference in luminance for each region of the front surface due to the precise arrangement and the spot shape due to the random arrangement.

Here, the position of the group pattern 20 may be randomly formed with respect to the X-pitch. This can minimize the moiré phenomenon as the position of the group pattern 20 is finely changed. That is, as described above, at least one of each of the group patterns formed in the longitudinal direction with respect to the light source may have a different arrangement interval.

However, when the positions of the group patterns 20 are too excessively randomly arranged and the distance between the group patterns 20 of the X-pitch becomes long, black dots or mottled shapes are generated.

Therefore, it may be desirable to limit the random ratio of the group patterns 20 to which positions are randomly applied to 50% or less in an arrangement method in which precise arrangement and random arrangement are simultaneously applied. However, the random ratio may vary depending on the number of group patterns 20 and the X-pitch and Y-pitch distances, and the positional arrangement of the group patterns 20 is random only for the arrangement method in which both precise and random arrangements are simultaneously applied. does not apply

The group pattern 20 may be formed to form a predetermined angle with respect to the surface on which the light source is incident based on the surface on which the dot pattern 10 is formed.

That is, when the group pattern 20 is formed in a bar shape, there is a possibility that the group pattern 20 that is far from the light source 30 may pass due to the straightness of the light. In this case, the light source 30 may be lost.

At this time, if the arrangement of the group patterns 20 is formed to form a predetermined angle with respect to the rate of change of Y-pitch based on the X-pitch or formed to form a predetermined angle with respect to the rate of change of X-pitch based on the Y-ptich As the light path is further secured, light can be dispersed even to the group pattern 20 far from the light source 30 .

A display device including a light guide plate having the above characteristics can be manufactured, and specific components of the display device are not limited.

6 is a diagram illustrating an external state of a light guide plate to which a group pattern arrangement structure according to an exemplary embodiment is applied.

As shown in FIG. 6, in the light guide plate 100 to which the arrangement structure of the group patterns 20 according to an embodiment is applied, the group patterns 20 of (b) are more precisely arranged than when the general pattern of (a) is applied. It can be confirmed that the defect A1 and the scratch A2 disappeared due to the dispersion of the light source 30 according to the application of any one arrangement structure among random arrangement and random arrangement.

Although the present invention has been described in detail through representative embodiments, those skilled in the art will understand that various modifications are possible to the above-described embodiments without departing from the scope of the present invention. will be. Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by all changes or modifications derived from the claims and equivalent concepts as well as the claims to be described later.

[Description of code]

100: light guide plate

10: dot pattern 20: group pattern

30: light source 40: row group

41: first row group 41: second row group

A1: Flaws A2: Scratches

Claims (5)

1. A light guide plate that emits a light source incident from the side to the front side,

   A plurality of dot patterns for dispersing light are provided on one side of the light guide plate, and a plurality of the dot patterns are densely packed to form a group pattern;

   A plurality of group patterns are formed in the horizontal and vertical directions based on the light incident surface, and the plurality of group patterns are formed at equal intervals in the horizontal and vertical directions. Of the random arrays formed at regular intervals and precision arrangements A light guide plate using a grouping pattern, characterized in that it is provided in at least one arrangement.
2. According to claim 1,

   At least one of the dot pattern and the group pattern is provided by changing the distribution density by position.
3. According to claim 1,

   The light guide plate using a grouping pattern, characterized in that the group pattern is formed in a zigzag pattern in a transverse direction based on the side surface.
4. According to claim 1,

   The light guide plate using a grouping pattern, characterized in that the group patterns are arranged differently from each other at mutual intervals between at least one pair of group patterns in the longitudinal direction.
5. A display device comprising the light guide plate according to any one of claims 1 to 6.

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