KR20070042860A - Light guide panel - Google Patents

Abstract

The present invention is to provide a high-brightness light guide plate having a reflection pattern that is specularly reflected from the bottom surface of the light guide plate using a line light source or a point light source as a light source, and further uses a light guide plate bar of the same reflection method as a uniform surface light source The change-out and incident the light guide plate as a light source provide a more uniform high brightness liquid crystal display device.

Light guide plate, Specular reflection, Inclined surface, V-shaped protrusion

Description

Light guide plate {LIGHT GUIDE PANEL}

1 is an exploded view of a conventional backlight unit;

2 to 4 are diagrams for explaining the properties of light in the light guide plate

5 is a view of refraction of light,

6 is a three-dimensional analysis of the refraction of light incident in the light guide plate,

8 to 11 are views for explaining the specular reflection theory of the present invention,

12 is a view for explaining the basic theory of the reflection pattern of the present invention,

13 to 21 illustrate various embodiments of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: light guide plate 110: upper surface

120: bottom 121: V-shaped protrusion

122: slope for surface use

200: light guide plate bar

The present invention relates to a light guide plate, and more particularly, to a high brightness light guide plate having improved reflection efficiency and reflection angle of light incident from a light source.

In general, the light guide plate is known as an important factor in determining the quantity and quality of light (diffusion angle, direct transmission light, diffuse reflection light) in the process of converting light from a linear or point light source into a surface light source. For example, a light guide plate is a key component of a backlight unit applied to a liquid crystal display ("LCD") and a flat panel display.

The backlight unit is composed of a direct method in which the light source is placed directly under the light transmitting surface according to the position of the light source to enable surface light emission, and a diffuse reflection and specular reflection at the bottom surface of the light guide plate by placing the light source on the side of the light guide plate. It can be divided into two ways to make the surface light emitting.

1 is a schematic configuration diagram of a backlight unit using a side light source according to the prior art.

The backlight unit includes a prism sheet 2, 3, a diffusion sheet 4, a reflection sheet 7, a light source 5 positioned on a side surface, a light source cover 6, and a light guide plate 8. Reference numeral 1 in Figure 1 is a protective sheet.

The general light guide plate 8 receives light emitted from a light source using acrylic resin, polycarbonate, or the like having good light transmittance, and diffuses and reflects the light path by printing or uneven processing on the bottom surface, so that the light path is formed on the upper surface of the light guide plate (ie, the emission surface). It is emitted to make a surface light source.

The reflective sheet 7 performs a function of reflecting back light exiting from the bottom surface and returning it back to the light guide plate 8.

The diffusion sheet 4 is primarily responsible for spreading the light transmitted from the front of the light guide plate 8 to spread it evenly over the light guide plate.

The light evenly spread from the diffusion sheet 4 is refracted and collected in accordance with the purpose of the flat panel display in the prism sheets 2 and 3 so that the light is finally emitted from the backlight surface at a uniform angle and luminance.

The light guide plate manufacturing technology is largely two, one is a screen printing method having a pattern of reflective material on the bottom surface, and the other is a V-shaped groove cutting method giving irregularities having fine roughness.

The screen printing method is an old method and has a low production cost and is a technique that has been developed and used to this day because of its advantages of mass production. Disadvantage is that there is a limit to increase the light guide plate brightness. Recently, the reflective film is printed, corroded, and embossed on a separate film, thereby adhering to the bottom of the light guide plate, thereby improving brightness and uniformity, but failing to increase brightness as much as V-type groove cutting.

The V-shaped groove cutting method has a considerable improvement and efficiency according to the depth of cut, the angular arrangement, and the cutting method.In particular, the cutting method has been developed from diamond blade cutting to laser cutting to enable depth, alignment accuracy, and fine grains. The efficiency of diffuse reflection was maximized.

However, the light guide plate of the prior art still does not satisfy the desire for high brightness.

One of the fundamental problems of not being able to realize high brightness in the prior art is that the light guide plate of the prior art is used as a surface light source because only a part of light diffused and reflected in the bottom reflection pattern is transmitted to the top surface of the light guide plate. Here, a part is known to be about 60% remaining from the entire part of the lamp light source. The amount of light lost is approximately as follows.

(1) fine amounts not explained by the theory of absorption, annihilation, total reflection and light according to the light transmittance of acrylic

(2) the amount remaining in the light source cover

(3) Among the light incident on the light guide plate, light incident at a horizontal and near horizontal angle (hereinafter referred to as "horizontal light") (within the influence of acrylic refractive index 1.49, within the critical angle of 42.1 ° when light is incident on acrylic in the air) And the light is refracted considerably in the horizontal direction.)

(4) The amount of light energy reduction due to diffuse reflection because the diffuse reflection is more than the specular reflection at the bottom of the light guide plate.

(5) The amount of light energy dissipated by continuous reflection in the light guide plate with or without reaching the reflective pattern plane late.

(6) Loss until light emitted from the light guide plate is collected through a diffusion sheet and a prism sheet for use in a liquid crystal display

The loss of light as described above occupies a large portion of the amount of light lost by the diffuse reflection on the bottom surface, and also has a structural problem that is not utilized as a surface light source of the diffusely reflected light, the amount is lost.

2 and 3 illustrate a state in which light is diffusely reflected in the light guide plate 8 by the reflection pattern S provided on the bottom surface of the conventional light guide plate 8.

As shown in FIG. 2, in the process of inducing diffusion to the top surface by diffuse reflection from the bottom surface, a large amount of light is not emitted and is re-reflected to rapidly lose light energy. Although the reflection pattern is brightly recognized by the human eye, only light with an angle within 84.2 ° (42.1 ° + 42.1 °) is emitted in the vertical direction of the diffused light, and light with other angles is the refractive index of acrylic. As a result, it remains in the light guide plate 8 and is re-reflected to diffused and reflected again in another reflection pattern, and the light energy is drastically reduced while repeating this process.

On the other hand, among the light emitted at an angle of less than 84.2 ° in the vertical direction, only light having a left angle of 20 ° around the vertical line perpendicular to the upper surface of the light guide plate, that is, an internal angle of 40 ° or less has strong energy, and the remaining light is emitted. Among the lights, light whose internal angle is 40 ° ~ 84.2 ° has weak energy and is not useful.

Verification of this phenomenon can be performed very easily.

That is, as shown in Figure 4, after scanning a single red linear light after the short one-shaped V-shaped groove cut (G) on the bottom surface is about 40 ° when viewed with the naked eye or white plate (W) in the upper portion of the cutting portion (G) It can be seen that only the light emitted within is projected, and light having an angle greater than that is weak in intensity, is released close to the horizontal angle of the light guide plate, or a large amount of light is reflected back into the light guide plate and thus cannot be used as a surface light source.

In addition, the conventional light guide plate 8 also has a problem in that a large amount of loss occurs in the process of being reflected back to the reflective sheet 7 and being incident on the light guide plate by being diffusely reflected below the reflective pattern. This can be sufficiently confirmed by the presence or absence of the reflective sheet, the upper layer brightness is measured differently according to the type of the reflective sheet.

The present invention is to solve the problems of the prior art as described above, to prevent the diffuse reflection inside the light guide plate, so that the loss due to the light energy dissipation is made to the minimum, the upper surface (light emitting surface) of the light guide plate This method aims to realize a high brightness, high efficiency light guiding plate which can emit as much light as possible by being specularly reflected vertically or close to vertical.

In other words, rather than inducing diffuse reflection, such as a V-shaped groove having a conventional fine roughness, the reflection structure is changed so that specular reflection occurs so that the light incident into the light guide plate is reflected as much as possible.

The purpose of the present invention is to provide a uniform high-brightness light guide plate using the light guide plate of the present invention as a light source by utilizing a light guide plate of the present invention by converting the point light source into a line light source and a surface light source.

In order to solve the above problems, the present invention is characterized in that a plurality of regular reflection inclined surface formed in a direction perpendicular to the incident light source is formed on the bottom surface of the light guide plate along the direction of incidence of the light source.

The specular inclined surface refers to an inclined surface processed to minimize diffuse reflection and maximize specular reflection. In the present invention, at least one surface is formed by a V-shaped protrusion having a specular inclined surface and a specular inclined surface having an inclination of 45 °. Is implemented.

The light guide plate in the above and hereinafter means a light guide plate having a narrow meaning, as well as a light guide plate utilized as a light guide plate, or a light guide plate assembly having a light guide plate bar attached to the light guide plate. It will be understood by those skilled in the art that the light guide plate, the light guide plate bar, or the light guide plate assembly have no problem in applying the basic concept of the present invention.

First, in the present invention, since the purpose of achieving a high brightness by changing the structure of the light guide plate as described above, for this purpose will be first described the theory about the light associated with the existing light guide plate.

The incident angle θ1 and the refraction angle θ2 of light incident from the light source and entering the light guide plate 100 (acrylic) have a relationship as shown in FIG. 5.

The medium n1 is the refractive index of air (1) and n2 is the refractive index of acrylic (1.49).

In this case, the relative refractive index is 1.49 / 1.

Of course, since the relative refractive index is 1 / 1.49 when the refractive angle is emitted into the air in the acrylic, the relationship between the incident angle and the refractive angle is reversed from the table of FIG. 5.

Here, when incident into the acrylic in the air, if the angle of incidence is 90 °, then the acrylic becomes the critical angle of 42.1 ° (hereinafter, 42.1 ° is sometimes referred to as 42 °).

When the incident angle is 73.5 ° or more, the refraction angle is 40 ° or more, and the effective component of light having such an incident angle is extremely insignificant.

As shown in (a) of FIG. 6, the light starting from the side light source causes the refraction of three components of the x-axis, the y-axis, and the z-axis to be caused by the refractive index of the acryl when the light enters the light guide plate (acrylic).

On the other hand, unless otherwise mentioned in the above and below, the incident direction of light refers to the x direction in the case as shown in FIG.

This is again divided into xz cross section, xy cross section, yz cross section as shown in (b), (c), (d) of FIG. The graph displayed on the right side of each drawing is a light vector amount distribution chart according to the refraction angle.

In the case of xz cross section in FIG. 6 (b), incident light may enter both 0 ° and 90 °, but due to total reflection, there is a difference in entry amount depending on the size of the angle, and the entrance amount decreases from 0 ° to 90 °. do. Light entering the acrylic has an angle within 0 ° to 42.1 ° due to the refractive index of the acrylic.

On the other hand, when the light entered into the acrylic is emitted to the upper surface of the light guide plate, the emission angle is 47.9 ° ~ 90 ° with respect to the normal perpendicular to the upper surface of the light guide plate, all of which is greater than the acrylic critical angle 42.1 ° It cannot be emitted outside, and all are totally reflected.

This point can be easily seen even if the light source is irradiated only on one surface of the transparent light guide plate without the reflection pattern, and no light is emitted from the upper and lower surfaces, and all the light exits to the opposite side of the light source.

In (c) and (d) of FIG. 6, when viewed from the xy cross section and the yz cross section side, all lights have an angle within 42.1 °, and thus all have an angle that can be emitted. However, this light itself has the characteristics of the cross section of xz, so that all the light is emitted from the side and the bottom, and exits to the opposite side of the light source.

Therefore, as shown in FIG. 6, the light in the LGP has a constant pattern as shown below.

1) Light incident on the light guide plate proceeds with an angle within 0 ° -threshold angle (42.1 °).

2) The closer the light incident to the light guide plate is at 0 °, the higher the energy of light.

3) The closer the light enters the light guide plate to the critical angle, the lower the energy of the light.

The basic principles of the present invention are described below.

By using the propagation of light having the pattern as described above, the V-shaped protrusion having the best reflection angle is formed on the bottom surface, and the light is subjected to the specular reflection treatment (the specular reflective coating film treatment) on the surface or the entire bottom surface of the V-shaped protrusion. By inducing specular reflection of the light guide plate of high brightness can be realized.

First, the specular reflection processing (the specular reflection coating film processing) will be described.

As the medium itself emits light, such as a diffuse reflection or a reflective sheet in a conventional printing dot method or a V-shaped groove cutting structure, light loss occurs. In order to eliminate such a loss, the reflected light itself must be specularly reflected, and for this purpose, the mirror surface and the reflective coating film treatment are useful methods.

This specular reflection treatment leads to specular reflection of all the light reached. That is, even when the light incident on the specularly inclined surface has an incident angle greater than the critical angle, all of the specular reflection is performed without being refracted, transmitted, or diffusely reflected.

Therefore, the specular reflection treatment (the specular reflection coating film treatment) is performed on the surface of the V-shaped protrusion (or the entire surface of the bottom surface of the light guide plate) embodied in the present invention, and the specular reflection treatment method is a vacuum deposition method which is a general mirror surface treatment technique. Aluminum deposition by nitrate, nitric acid may be possible by various methods such as a deposition method, chromium plating, a white reflective coating film.

The reflection coating film treatment is known as a reflection coating film treatment for specular use and a reflection coating film treatment for diffuse reflection. The technique applied to the present invention relates to a reflection coating film treatment for specular use.

7 illustrates a state in which the linear light source is incident on the light guide plate and refracted at an angle of 0 ° to 42 ° and then reflected from the V-shaped protrusion.

When specular reflection occurs, the angle of incidence of light and the angle of reflection of light are the same with respect to the surface of the specular use.

As shown in (a), (b), and (c) of FIG. 7, in order to configure the V-shaped protrusion so that the center is reflected vertically, the angle formed by the V-shaped protrusion must be 111 °, and the entire light source can be emitted. The inner angle of the V-shaped protrusion is 90 ° to 132 °.

In FIG. 7, the light incident on the specularly inclined surface is a dotted arrow, and the light reflected on the specularly inclined surface is a solid arrow.

In addition, in the present embodiment, it is assumed that the V-shaped protrusion is formed to be opened at the same angle with respect to a normal perpendicular to the upper surface of the light guide plate. This is because the V-shaped protrusion is formed by two specularly inclined surfaces when the light sources are positioned on both sides of the LGP, and the two specularly inclined surfaces will have the same inclination with respect to a normal perpendicular to the upper surface of the LGP.

However, if the light source is located only on one side of the light guide plate, there is only one specular inclined surface necessary for specular reflection of the light source. In other words, the V-shaped protrusion is basically formed by two inclined surfaces, but at this time, the inclined surface which is meaningful as a semi-reflective inclined surface becomes only one surface. In this case, the inclined surface used for the specular reflection requires a certain inclination with respect to a normal perpendicular to the upper surface of the light guide plate, and when applied to FIG. 7, the inclination is 45 ° to 66 °. At this time, the inclined surface that is not utilized as the surface reflecting slope may have a different angle from the inclined surface utilized as the surface reflecting slope.

Fig. 8 shows the reflection angle at the V-shaped protrusion when a point light source having a wide width of 130 degrees (that is, a 130 degrees angle) is incident on the light guide plate.

The point light source generally has a wide width of 130 °, and when the width is 130 °, the light incident on the light guide plate is incident on the light guide plate with a width of 65 ° upward and 65 ° downward with respect to the horizontal. Is -37.5 ° to 0 ° (horizontal) to 37.5 ° according to the relationship in FIG. 5. At this time, -37.5 ° to 0 ° light that is refracted to the top is totally reflected at the top surface and is redirected to 0 ° to 37.5 ° light, so that all the light has a direction of 0 ° to 37.5 ° in the light guide plate. While facing the floor.

Therefore, the point light source having a wide width of 130 ° has a refractive angle of 0 ° to 37.5 ° in the light guide plate, and as shown in (a), (b) and (c) of FIG. 8, the V-shaped protrusion is configured so that the center is reflected vertically. In order to achieve this, the inside angle of the V-shaped protrusion is 108.75 °, and the inside angle of the V-shaped protrusion which all the light sources can emit is 85.5 ° to 132 °.

Of course, even in this case, if only one inclined plane of the V-shaped protrusions is meaningful as a specular inclined plane, the entire light source when the specular inclined plane has an inclination of 42.75 ° to 66 ° with respect to a normal perpendicular to the upper surface of the light guide plate. It is possible to exit.

On the other hand, when the point light source (width is about 0 ° to 10 °) that is horizontal light, the angle of refraction generated by incident on the light guide plate is almost 0 ° (ie, horizontal) according to the relationship of FIG. 5. At this time, the inner angle of the V-shaped protrusion that vertically reflects the refractive angle of 0 ° is 90 °. However, when the horizontal light is incident, the V-shaped protrusion as shown in FIG. 9 (a) is not necessary. In this case, a specularly inclined plane having a 45 ° inclination as shown in FIG. 9 (b) is sufficient. That is, since the 45 ° specular reflection slope is raised by the height of the step in the step shape, and the incident angle (45 °) with respect to the specular reflection slope is larger than the critical angle (42.1 °) of the light guide plate, the surface of the specular reflection slope (or the bottom surface of the light guide plate) All light is specularly reflected and emitted vertically to the upper surface (emission surface) even if no specular reflection coating film treatment is applied to the entire surface.

The light emitted from the light guide plate is incident on the incident surface polarizing sheet of the liquid crystal display and passes through all the structures inside the liquid crystal display. In this case, the width of light that can be effectively incident on the liquid crystal display device has gradually increased in efficiency due to the development of a polarizing sheet, a liquid crystal, a liquid crystal driving device, and exposure printing. Recently, a prism light guide plate and a prism sheet formed with a prism on an upper exit surface of the light guide plate mainly use about 90 ° prism angle, and the maximum condensing emission square is about 45 °.

The interior angle of the V-shaped protrusion suitable for the maximum exit angle of 45 ° is 118.3 °, as shown in FIG. 10.

The thickness of the light guide plate requires an ever thinner thickness which is advantageous in terms of light efficiency and finished product design.

For example, when a 2-inch light guide plate of 0.4 mm thickness is used as a light source, a 130-degree wide point light source is used as a light source, and the emission width of the energetic light is about 0.14 mm in a V-shaped protrusion having a 108.75-degree internal angle. At this time, in order to make a uniform surface light source, it is desirable to overlap the emission width of the strong light more than two times. For this purpose, when the distance (pitch) of the V-shaped protrusions is 0.07 mm and the light guide plate length is 45 mm, the number of V-shaped protrusions is about 640, the minimum protrusion height is about 0.006 mm, the maximum protrusion height is about 0.020 mm, and the difference between the maximum protrusion height and the minimum protrusion height. The average height difference between each of the 0.014 mm and V-shaped protrusions is about 0.000022 mm. Since the specification is a mold requiring a degree of height axis machining in units of 10 nm, it may be a difficult task in the mold manufacturing and mass production process.

Therefore, it may be desirable to utilize the maximum condensing emission angle of the liquid crystal display (eg, about 45 °). FIG. 11B illustrates a light guide plate using the maximum condensing emission angle. At this time, the emission distribution of the light with strong energy can be more widely and evenly distributed, so that the uniformity of the surface light source can be improved.

Therefore, the angle of the V-shaped protrusion is suitable to be 100 ° to 120 ° to maximize the light energy and to make a uniform surface light source. The angle of the V-shaped protrusion can be applied more widely in commercial display panels, lighting devices, and architectural lighting. There will be.

The internal angle of the V-projection is 100 ° to 120 °, which means that when only one inclined surface is used as the specular inclined surface in the V-projection, the specularly inclined surface is 50 ° to 60 with respect to the normal perpendicular to the upper surface of the light guide plate. Equivalent to having a slope of °.

In FIGS. 11A and 11B, the upper graph is a graph of the light energy of the emitted light at the point where the light is emitted.

As described above, in the horizontal light source, it is not necessary to use the V-shaped protrusion, and it is sufficient that the 45 ° regular reflection inclined surface is formed stepwise.

Next, a description will be given of the pattern of the specularly inclined surface.

First, the screen printing method has been used for more than 20 years, and many advances have been made with respect to patterns.

The principle of the pattern structure of all the light guide plates is the same as that of the screen printing dot method.

That is, the light guide plate pattern has two roles. One is to reflect the light by diffusing and printing it like a printing part, and the other is to be specularly reflecting as the non-printing part. The latter is to send light to the farthest dot from the light source and to diffuse and reflect from the farthest dot. To make it work.

The gradation etching method is also the same principle, with the fine distribution of printing and non-printing parts.

The dot pattern becomes larger and larger as it moves away from the light on the same X axis (see FIG. 6), and is arranged in dots of the same size on the Y axis (see FIG. 6).

The pattern of this invention is similar to this dot pattern structure.

Fig. 12A is a schematic diagram of a conventional dot pattern, and Fig. 12B shows a pattern of a V-shaped protrusion according to the present invention.

In Fig. 12 (a), a-b is a light incident part and is a part which is diffused by reflecting light, and b-c is a part which is specularly reflected and sent back.

In FIG. 12B, e-f is a light incident part, f-i is a part of specular reflection and output, and f-g is a part of specular reflection and sent back.

Although a-b and e-f, b-c, and f-g have different cross-sectional sizes, the sum of each a-b dot area and the e-f area are the same on the plane (xy plane), and the areas of b-c and f-g are the same. In conclusion, the sum of the total area of dots in the light guide plate (the sum of the areas of a-b in FIG. 12) and the area of the V-shaped protrusion (the area of the e-f section in FIG. 12) coincide. Therefore, the two patterns differ only in shape, but have the same pattern principle or function.

Comparing the two pattern structures, the dot pattern is diffusely reflected and emits very little compared to the amount of light received, and the light energy and the emission angle after the emission are not good. On the other hand, in the pattern of the V-shaped protrusion, all the light incident amounts are specularly reflected and emitted with high light energy at a vertical angle.

In addition, the dot can only achieve the precision of the screen halftone size (5/100 mm), but the V-shaped protrusion can realize the precise pattern of about 10 nm, and can provide a high brightness light guide plate having high uniformity of surface light source and high utilization of light. .

Hereinafter, embodiments according to the present invention will be described.

First embodiment (see FIG. 13)

In the light guide plate 100 having a uniform thickness, a plurality of V-shaped protrusions 121 having a predetermined internal angle are formed on the bottom surface 120. One V-shaped protrusion 121 is formed while having the same shape, that is, the same cross section, at right angles (ie, y-direction in FIG. 6) with respect to the incident light source. In addition, a plurality of V-shaped protrusions 121 are provided along the incident direction of the light source. At this time, each of the V-shaped protrusions 121 has the same internal angle.

The size of the surface where the light source is located, that is, the V-shaped protrusion 121 located near the light incident surface 130 (that is, the height protruding downward in the present embodiment) is small, and the V-shaped protrusion 121 is disposed on the bottom surface 120. The spacing of the face on which the) is not formed (ie, the spacing between the V-shaped protrusions) is wide. As the distance from the light source increases, the protruding height of the V-shaped protrusion 121 becomes larger, and the interval between the surfaces where the V-shaped protrusion 121 is not formed on the bottom surface 120 (that is, the gap between the V-shaped protrusions) becomes narrower.

That is, when the light source is located on both sides as shown in (a) of FIG. 13, the V-shaped protrusion 121 having a small protrusion height is formed from the light receiving surfaces 130 on both sides, and then the V-shaped protrusion having a high protrusion height toward the center portion. 121 is formed, and is symmetric about the center.

When the light source is located on one side, as shown in FIG. A V-shaped protrusion 121 having a height is formed.

In this case, the narrower the interval between the V-shaped protrusions 121 is, the more precise the specular reflection pattern is achieved, and a uniform surface light source can be made.

On the other hand, the size difference between adjacent protrusions occurring along the direction of incidence of the light source increases further away from the light source. Therefore, if the three vertices of the V-shaped protrusions are connected to the three corresponding vertices of the adjacent V-shaped protrusions, respectively, the aspherical secondary increases as the distance increases from the light source rather than in a linear proportion. The curve can be seen.

Second embodiment (see FIG. 14)

In the first embodiment, when the heights of the end portions of the V-shaped protrusions 121 are equal to each other and placed on the same plane (that is, a horizontal plane), stairs are formed in the light guide plate 100 by the difference in the height of the protrusions. That is, the bottom surface 120 of the light guide plate 100 is formed in a step shape along the direction of incidence of the light source, and the V-shaped protrusion 121 is formed at the start or end of each step. Such an embodiment may utilize horizontal light as much as the height of the stairs, thereby increasing the brightness.

Third embodiment (see FIG. 15)

In the second exemplary embodiment, a small height is added to one inclined surface of the V-shaped protrusion 121 on the light incident surface 130 side, and as the distance from the light source increases, a separate height is increased to one inclined surface of the V-shaped protrusion 121. By adding and raising, the lower vertex of the V-shaped protrusion 121 is raised by the added height. This makes it possible to utilize horizontal light as compared to the second embodiment by the added height, so that the brightness is further increased.

Fourth embodiment (see FIG. 16)

In the first embodiment, one V-shaped protrusion 121 may be divided into a plurality of divided V-shaped protrusions 121a having the same protrusion angle, and may be implemented as shown in FIG. 16. Since the sum of the divided V-shaped protrusions 121a divided into several parts is equal to the area of the light incident portion of one original V-shaped protrusion 121, the amount of light incident and the amount of reflection are basically the same.

The divided V-shaped protrusion 121a in which one V-shaped protrusion 121 is divided may obtain a more uniform surface light source than one V-shaped protrusion 121.

-Fifth embodiment (see Fig. 17)

As shown in FIG. 17, the size and the protrusion angle of the plurality of V-shaped protrusions 121 may be implemented in the same manner.

At this time, the distance between the V-shaped protrusions 121 on the light incident surface 130 is wider, and the distance between the V-shaped protrusions 121 is narrower as the distance from the light source increases.

When the pattern is formed in this manner, the mold fabrication process is simplified, and a uniform surface light source can be obtained as a precise pattern having a narrow gap between the V-shaped protrusions 121.

Sixth embodiment (see FIG. 18)

In this embodiment, the bottom surface 120 itself of the light guide plate 100 is inclined. That is, the bottom surface 120 of the light guide plate 100 is an inclined bottom surface 120 whose height increases along the incident direction of the light source.

Therefore, the thickness of the light guide plate 100 is closer to the light incident surface 130 and the thickness of the light guide plate 100 becomes thinner as the distance from the light incident surface 130 increases.

This is different from the light guide plate 100 in which the bottom surface 120 and the top surface 110 of the first to fifth embodiments are parallel.

(A) and (b) of FIG. 18 is a wedge shape in which a light source is located at one side, and FIG. 18 (c) shows a butterfly shape in which the thickness becomes thinner toward the center part with the light sources located at both sides.

Thus, the inclined to the bottom surface 120 itself, the V-shaped protrusion 121 on the bottom surface 120 was carried out with reference to the above embodiments.

FIG. 18A illustrates the concept of the first embodiment (FIG. 13), and FIGS. 18B and 18C apply the concept of the fifth embodiment (FIG. 17).

Such shapes may increase brightness by partially utilizing horizontal light. Of course, the horizontal light utilization rate is lower than that of the third embodiment (Fig. 15), but a uniform emission amount can be obtained with a precise pattern.

Seventh embodiment (see FIG. 19)

In the light guide plate in which the V-shaped protrusions are formed in the first to sixth embodiments, only the surface of the V-shaped protrusion or the entire bottom surface (including the V-shaped protrusion) of the light guide plate is subjected to the specular reflection treatment (the specular reflection coating film treatment). Should be

However, in a light guide plate using horizontal or near horizontal light as a light source, it is efficient that the specularly inclined surface 122 having a 45 ° inclination without a V-shaped protrusion is formed in a step shape. At this time, the reflective coating film treatment is unnecessary on the surface of the surface of the regular reflection inclined surface 122 having an inclination of 45 °.

FIG. 19A illustrates a 45 ° specularly inclined surface 122 that is lower at the light incident surface 130 and increases as the distance from the light source increases, and FIG. 19B is a specularly inclined surface having the same size. The distance between the light reflection surface 130 and the light reflection surface 130 is wider and the distance between the specularly inclined surfaces 122 becomes smaller as the distance from the light source increases.

That is, the bottom surface 120 of the light guide plate 100 rises in a step shape along the direction of incidence of the light source, and the specular reflection slope 122 is formed at each start or end of each step.

8th embodiment (see FIG. 20)

In order to be used as a uniform incident surface light source in a small light guide plate using two or less point light sources, the light guide plate bar 200 is separately manufactured using the patterns of the first to seventh embodiments, and the light guide plate ( 100, a uniform surface light source may be made in the light guide plate bar 200 to be incident on the light guide plate 100. That is, the concept of the present invention is applied to the light guide plate bar 200.

This increases the utilization of the light source itself when using a point light source, and can create a uniform surface light source that eliminates the bright lines that may occur in the light guide plate in which the prism is formed on the incident surface. Also, by using the light guide plate bar, the diffused prism sheet It is possible to provide a uniform surface light source to a liquid crystal display device as a high brightness high efficiency light guide plate which is not necessary.

-Ninth embodiment (see FIG. 21)

In FIG. 20, in the small light guide plate using two or less horizontal light sources, the light guide plate bar and the light guide plate are integrally formed by applying the pattern of the seventh embodiment to the end of the light incident end, without separately mounting the light guide plate bars as in the eighth embodiment. Do it.

As a result, in the present embodiment, the specularly inclined surface is formed on the side surface 140 of the light guide plate 100.

The above embodiments are only preferred embodiments of the present invention, and the technical idea of the present invention may be variously modified or adjusted by those skilled in the art. Such modifications and adjustments fall within the scope of the present invention if they use the technical idea of the present invention.

As described above, according to the present invention, high brightness and high efficiency of the liquid crystal display can be achieved by using the specular reflection without using the conventional diffuse reflection, and the reflection sheet, the diffusion sheet and the prism sheet are unnecessary, thereby simplifying the parts and the assembly cost. Due to the reduction of the production cost is very low, the assembly is simple and good using fewer parts.

In addition, the assembly structure or module structure is simple, the final overall thickness after assembly is thin, the product design is excellent.

In addition, it is possible to realize high definition image quality in a liquid crystal display device with a uniform surface light source, and to reduce the power consumption due to the reduction of the light source according to the high brightness, thereby increasing the use time of the portable product.

In addition, the amount of emitted light is greatly increased compared to the light source, and the emission angle can be arbitrarily adjusted, and thus it can be utilized as various light sources such as commercial display panels, architectural lighting, and lighting equipment.

Claims (15)

A light guide plate, characterized in that a plurality of regular reflection inclined surface formed in a direction perpendicular to the incident light source is formed on the bottom surface of the light guide plate along the direction of incidence of the light source. According to claim 1, wherein the specular inclined surface is at least one surface of both sides of the V-shaped projection formed on the bottom surface of the light guide plate, the plurality of V-shaped projections all have the same internal angle, the surface of the V-shaped projection is a specular reflection The light guide plate characterized by the above-mentioned treatment. The method of claim 2, The specularly inclined surface of the V-shaped protrusion may have a slope between 50 ° and 60 ° with respect to a normal perpendicular to the upper surface of the light guide plate. The method of claim 2 or 3, The specular reflection process is a light guide plate, characterized in that the specular reflection coating film treatment. The method of claim 2 or 3, The specular reflection process is performed on the entire bottom surface of the light guide plate. The light guide plate according to claim 2 or 3, wherein the size of the V-shaped protrusion becomes larger as it moves away from the light source. The method of claim 6, The size difference between the V-shaped protrusions generated along the direction of incidence of the light source increases further away from the light source. The method of claim 7, wherein The bottom surface of the light guide plate is formed in a step shape along the direction of incidence of the light source, wherein the V-shaped protrusion is formed at the beginning of each step. The light guide plate according to claim 2 or 3, wherein the distance between the V-shaped protrusions becomes narrower as the distance from the light source increases. The method of claim 2 or 3, The bottom surface of the light guide plate is a light guide plate, characterized in that the inclined bottom surface is increased in height along the incident direction of the light source. The method of claim 1, The specular reflecting inclined surface is a specular reflecting inclined surface having an inclination of 45 ° with respect to the incident direction of the light source, and the bottom surface of the light guide plate is formed in a step shape along the incident direction of the light source, and the specular reflecting inclined surface is at least the beginning of each step. The light guide plate is formed for each site | part. The method of claim 11, The light guide plate, characterized in that the size of the specular use is larger the farther away from the light source. The method of claim 11, The light guide plate, characterized in that the distance between the surface of the specular use for reflection becomes narrower as the distance from the light source. The light guide plate according to claim 1, wherein the light guide plate is used as a light guide plate bar. In the light guide plate, a plurality of regular reflection inclined surfaces that are formed to extend in a direction perpendicular to the incident light source are formed on the side surface of the light guide plate along a direction of incidence of the light source. The light guide plate has a specular reflection slope, the side surface of the light guide plate is formed in a step shape along the direction of incidence of the light source, and the specular reflection slope is formed at least at each start of each step.

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