KR100438053B1 - Light board for apparatus of back-light in formed of side-light, and method of pattern design thereof - Google Patents

Abstract

The present invention relates to a light guide plate and a method of designing a pattern of the light guide plate so that the reflection pattern is processed so that the luminance value of the light derived from the light guide plate of the side light type backlight device is equal, and the light guide plate according to the present invention has a predetermined distance in one direction. The pattern is arranged, and the method of arranging the pattern includes the first step of dividing an area in the light guide plate into a predetermined unit area having a dividing plane parallel to the incident surface of light and having the same width, and the area in the divided unit area. And a third step of variably setting the number of reflection patterns to be designed in each unit area by the second step of calculating the respective reflectances and the calculated reflectances. It relates to a pattern design method of.

According to the present invention, the luminance value of the derived light is uniform with respect to the surface of the light guide plate so as to best meet the original purpose of the light guide plate, and the luminance value of the derived light is increased to increase the light reflectivity of the light guide plate, thereby achieving high efficiency as well as production time. It has the effect of shortening.

Description

Light board for apparatus of back-light in formed of side-light, and method of pattern design

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate and a pattern design method in which the reflection pattern is processed so that the luminance value of the light derived from the light guide plate of the side light type backlight device is equal, and more particularly, a point where the distance from the light guide plate to the light source is close. The present invention relates to a pattern design method of a light guide plate and a light guide plate of a side light type backlight device fabricated such that the distance between the reflective patterns is long and the distance from the light guide plate to the light source is short.

Recently, the light guide plate backlight, which has been spotlighted as a liquid crystal display (LCD) back light source, is increasing as the demand for LCD increases. Currently, the application range is gradually expanded to laptops, desktop PCs, and liquid crystal TVs. The LCD market is growing more than 30% a year, and the light guide panel backlight industry is also growing.

Unlike the Plasma Display Panel (PDP) and Field Emission Display (FED), the display by the LCD itself is a light-receiving element, so it is a back light source type that can maintain uniform brightness across the screen. Backlight is required.

Currently used backlights include electroluminescent (EL) backlights, LED backlights, and CCFL (Cold Cathode Fluorescent Lamp) backlights. Among them, CCFL backlight is preferred because of its low power consumption and very bright white light. It is thin and low power consumption. CCFL backlight has a direct type and side light type, and recently, research on the side light type is being actively conducted according to the demand for thinner and lighter display unit. In addition, since the side light type light guide plate provides flat illumination, it is used as a flat panel display in various fields as well as notebook PCs and liquid crystal TVs, and its range is gradually spreading.

1 shows a light incidence portion of a side light type backlight device, including a light guide plate 100 and a fluorescent lamp 10; A lamp case 11 protecting the fluorescent lamp 10; A reflection plate 12 attached to the lamp case 11 to reflect light incident from the fluorescent lamp 10; And a diffuser plate 13 for diffusing the reflected light to make it uniform.

In addition, Figure 2 is shown to explain the path of the light in the light guide plate designed by the vickering method, the light guide plate 100 is an essential element included in all LCD, the side of the light guide plate 100, the acrylic plate is the main material When light is incident on the light guide, the light travels straight through the light guide plate 100 and is then outputted by changing the direction of travel toward the upper end of the light guide plate by a V-shaped convex concave-convex surface patterned on the bottom surface of the light guide plate by v-cutting.

For reference, the length of the light guide plate 100 is L in the direction in which light is incident, and the intervals between the unevennesses T1, T2, T3,..., And Tn formed on the bottom surface thereof are respectively L1, L2, L3,. , Ln and the luminance of the light reflected from them and directed toward the upper end thereof is output light 1, output light 2, output light 3,... In terms of the output light n, the designer has based on his or her own experience since there was no modular program to calculate the distance between the irregularities corresponding to the reflection pattern for converting the path of light in the light guide plate 100. If the spacing of the reflection patterns is determined inconsistently and the spacing of the designed reflection patterns is the same (L1 = L2 = L3 =… = Ln), for example, if the spacing of the reflection patterns is 1 mm, the cross section of the light guide plate 100 Is as shown in FIG. 3A.

If n concave-convex patterns are designed in the light guide plate 100 and the spacing between them is the same as 1 mm, the luminance value of each unit of light derived from the light guide plate 100 is as shown in FIG. 3B. The luminance value of each unit region is light that is equally divided into unit regions according to the distance traveled in the light guide plate 100 by light incident from an external light source (the fluorescent lamp 10 in FIG. 1), and is reflected from each region. This is to obtain the luminance value of. When the area is divided by 1cm unit, 10 unevenness is included in each unit area, and the luminance value of light derived from 10 unevenness in each unit area is shown in the graph as shown in FIG. 3B. Will be. Therefore, it can be seen that the luminance value in the unit region where the distance from the light guide plate is far from the light source is considerably lower than the luminance value in the unit region where the distance to the light source is close (output light 1> output light 2> output). Light 3>…> output light n). On the other hand, even if the designer presumes such a result and designed the distance of the reflection pattern differently from the above-mentioned example, it is derived because there is no prescribed program or module capable of compensating the distance of the reflection pattern from the resulting luminance value distribution. Since it was never easy to make the luminance value of the light uniform, there are many attempts to solve this problem.

As described above, the biggest problem in the conventional side light type backlight device is that since the fluorescent lamp 10 corresponding to the light source is located on one side of the light guide plate, the entire surface of the light guide plate 100 is closer to the light source. Since the emitted light has a much larger luminance value than the light derived from the far side from the light source, the luminance value of the light derived from the entire surface of the light guide plate 100 is uneven with respect to the derived surface.

Accordingly, the present invention has been created to solve the above problems, and the light guide plate and the pattern design method of the light guide plate of the side light type backlight device having a uniform luminance distribution with respect to the surface of the light incident from the light guide plate incident from the light source. The purpose is to provide.

In addition, another object of the present invention is to provide a light guide plate and a pattern design method of the light guide plate of the side light type backlight device in which the light derived from the light guide plate has an equally high brightness.

1 illustrates a light incident part of a side light type backlight device,

FIG. 2 is a diagram illustrating a path of light in a light guide plate patterned by a breaking method.

3A is a cross-sectional view of a light guide plate in which a reflection pattern is conventionally designed.

3B is a graph illustrating luminance values of light derived from the light guide plate of FIG. 3A;

4A is a cross-sectional view of a light guide plate in which a reflective pattern is designed in one direction according to an embodiment of the present invention.

FIG. 4B is a graph illustrating luminance values of light derived from the light guide plate of FIG. 4A;

5A is a cross-sectional view of a light guide plate having a reflective pattern designed in both directions according to an embodiment of the present invention.

FIG. 5B is a graph showing luminance values of light derived from the light guide plate of FIG. 5A for each unit area;

FIG. 6A is a table illustrating a luminance value of light derived from the light guide plate further provided with a reflecting plate designed with a reflective pattern in both directions according to an exemplary embodiment of the present invention.

FIG. 6B is a graph showing luminance values of the table shown in FIG. 6A;

FIG. 6C is a table illustrating a luminance value of light derived from the reflecting plate, two diffuser plates, and a prism in a light guide plate in which a reflective pattern is designed in both directions according to an embodiment of the present invention.

FIG. 6D is a graph showing luminance values of the table shown in FIG. 6C;

7 is a flowchart according to an embodiment of the present invention,

8 is a flowchart according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10 fluorescent lamp 11: lamp case

12: reflector 13: diffuser

100: LGP 200: Liquid Crystal Display (LCD)

The light guide plate of the side light type backlight device according to the present invention for achieving the above object has a predetermined distance in one direction while the pattern of the V-shaped irregularities processed by the vickering method is arranged, the predetermined distance, The light guide plate having the same distance in one direction has a divided surface parallel to the incident surface of light, and is divided into unit regions having the same width, and the reflectances calculated by calculating the reflectance for each region in the divided unit regions are calculated for each unit region. And a variable number of reflection patterns to be designed within. In the pattern design method of the light guide plate, in the pattern design of the side light-type light guide plate by the vitting method, the area in the light guide plate is divided in parallel with the incident surface of light. The first step of dividing into a predetermined unit area having the same width, the divided unit zero A second step of calculating the reflectivity of each region and in that it is characterized in comprising a third step of setting the variable number of the reflection pattern to be designed in each unit area by the calculated reflectivity.

According to the present invention, in the pattern design of a side light type light guide plate by a vickering method, a first step of measuring initial values inherent to the light guide plate, and the measured initial values of the reflective pattern to be disposed on the x and y axes, A second step of setting the number of lines, a third step of calculating the distance between lines by the line interval trend function from the set number of lines, and a fourth step of comparing the sum of the calculated distances with a predetermined reference value And a fifth step of variably adjusting the separation distance based on the comparison result.

In the light guide plate pattern design method according to the present invention as described above, the light guide plate is virtually divided into a predetermined unit region so as to have a dividing plane parallel to the incident surface of light. The reflectance for each divided area is calculated by a specified formula, and the calculated reflectance is substituted into the formula to recalculate the spacing between reflection patterns to be designed in each unit region, thereby designing a reflection pattern having the calculated interval in each unit region. Just do it.

In addition, the present invention measures the initial values unique to the light guide plate itself, and sets the number of lines of the reflection pattern to be designed in the light guide plate by using the measured initial values. When the number of lines is set, the distance between lines is calculated by the line trend function, and the distance between lines is adjusted according to the sum of the calculated distances. In other words, if the calculated distance is larger than the reference value, the coefficient of the line direction function is adjusted small so that the distance between the lines is narrowed.If the calculated distance is smaller than the reference value, the coefficient of the line direction function is adjusted. The larger the distance, the greater the separation between the lines.

Although the light guide plate of the side light type backlight device according to the present invention may be applied to a design by other methods other than a vcutting method, hereinafter, only the preferred embodiment of the pattern design method of the light guide plate according to the present invention will be described with reference to the accompanying drawings. It will be described in detail.

4A is a cross-sectional view of a light guide plate in which a reflective pattern is designed in a unidirectional direction according to an embodiment of the present invention. Referring to FIG.

First, the area of the light guide plate is divided so as to be parallel to the incident surface of the light incident from the outside. In this case, the divided surface is such that the traveling distance of the light in the light guide plate is constant. That is, assuming that the incident direction of light is the x-axis, the split surface is perpendicular to the x-axis.

For example, when the light guide plate is divided into a unit area of 1 mm in the x-axis direction as shown in FIG. 4A, if the length L of the light guide plate in the x-axis direction is 200 mm, the number Ns of the unit areas is 200. The light guide plate is composed of 200 unit areas A1, A2,... Having 1 mm in the x-axis direction. Is divided into A200 (S10).

As described above, when Ns unit regions are divided in the light guide plate, the same line of reflection as that formed in FIG. The pattern is processed (S11) (L1 = L2 = ... = L200) and the reflectance in the light guide plate is calculated by measuring the amount of light for each region derived from the processed reflection pattern (S12) (S13).

In more detail, the total incident light amount I (0) of the fluorescent lamp 10 incident on the light guide plate from the outside is normally given as a specification at the time of shipment from the factory. By measuring I (0)) and the amount of light I (n) derived from each region and substituting the following equation (1), the reflectance R in the light guide plate can be obtained.

I (n) = I (0) (1-R) ^n-1 R Expression (1)

Where n corresponds to the order of each unit area and n is 1, 2, 3,... Has a value of 200.

Also, by substituting the number Ns of unit regions into Equation (2), the reflectance r (n) for each unit region can be obtained (S20).

r (n) = 1 / {Ns- (n-1)} equation (2)

Substituting 200 according to the above embodiment in Ns, which is the number of unit regions of Equation (2), becomes as in Equation (2-1),

r (n) = 1 / {200- (n-1)} equation (2-1)

Where n = 1,2,3,… Substituting, 200 respectively,

n = 1, r (1) = 1 / {200- (1-1)} = 1/200 = 0.0050

n = 50, r (50) = 1 / {200- (50-1)} = 1/151 = 0.0066

n = 100, r (100) = 1 / {200- (100-1)} = 1/101 = 0.0099

n = 200, r (200) = 1 / {200- (200-1)} = 1.0000

As a result, the longer the incident distance of light, the greater the reflectance {r (n)} of each unit region is calculated. Where R is the reflectance over the entire light guide plate, and r (n) is the reflectance measured within that n unit area.

By substituting the calculated reflectance value for each unit region into Equation (3), the distance L (n) between the reflection patterns in each region can be calculated (S21), and L = 200, Ns according to the above embodiment. Substituting = 200, r (n) gives:

L (n) = {R / r (n)} {L / Ns} equation (3)

n = 1, L (1) = {R / r (1)} {200/200} = (R / 0.005) = 200R

n = 50, L (50) = {R / r (n)} {L / Ns} = (R / 0.006) = 151R

n = 100, L (100) = {R / r (n)} {L / Ns} = (R / 0.0099) = 101R

n = 200, L (200) = {R / r (n)} {L / Ns} = (R / 1) = R

That is, the distance between the reflection patterns to be designed in each unit region becomes shorter as the incident distance of light becomes longer, which means that the number of reflection patterns is designed to be larger in the unit region where the incident distance of light is longer and reflected in the unit region where the incident distance of light is shorter. It means that the number of patterns is designed to be small. Since the amount of light incident on the unit region having a short incident distance of light in the light guide plate is relatively large, the number of reflection patterns is designed to be small and the amount of light incident on the unit region where the incident distance of light is far away. Is relatively small, so that the luminance of the light derived by designing a larger number of reflection patterns (S22) is uniformly uniform with respect to the surface of the light guide plate. The luminance value of the light derived by the designed light guide plate is illustrated in FIG. 4B. As a result, a uniform distribution is achieved.

In the above description, only the unit areas having the same spacing in the direction in which light is incident in the light guide plate, that is, in the x-axis direction of the bottom surface of the light guide plate, which are assumed above, are diffusely reflected from the side, bottom, etc. of the light that is not incident and derived from the light guide plate. In order to maximize the light incident on the light guide plate, a reflection pattern having a predetermined distance (Ly1 = Ly2 =… Lyn) in a y-axis direction perpendicular to the x-axis on the bottom surface of the light guide plate may be designed in a line. Since the unit regions equally divided in the y-axis direction are generally uniform in the amount of light derived therefrom, a reflection pattern having a constant interval in the y-axis direction can be designed without any separate process. When the reflective pattern is designed, the lattice-shaped reflective pattern is formed on the bottom of the light guide plate, and the luminance value of the light is increased as compared with the case where the reflective pattern is formed only on the x-axis or the y-axis. .

However, the most preferable interval of the reflection pattern in the y-axis direction mentioned above may vary slightly depending on the characteristics of the light source. For example, when the fluorescent lamp corresponding to the light source is CCFL, the same length as the y-axis of the light guide plate may be used. Even if it has been selected to have, because the distribution of the dielectric in the fluorescent lamp emits a greater amount of light than the two edges in the center, as shown in Figure 5a to set the interval between the reflection pattern is longer from the edge to the center (Ly1 <Ly2 <Ly3 <… <Lyn) is more preferable, and the luminance value derived from the light guide plate designed in both directions of the x and y axes has the distribution as shown in FIG. 5B and is derived from the light guide plate designed only in the x axis unidirectional direction. It can be seen that the luminance value derived compared to FIG. 4B, which is a luminance value graph, is increased.

In the above-described embodiment, in the design of the reflection pattern in the x-axis direction corresponding to the direction in which light is incident, the light guide plate is divided at uniform intervals with respect to the x-axis direction, and the luminance value of each divided unit region is divided. By calculating the number of reflection patterns to be designed in the unit region and summarizing them in the light guide plate, the reflection pattern is designed using various inherent data of the light guide plate without dividing the light guide plate into several unit regions. How to describe the method of the embodiment according to the present invention is shown in FIG.

In this method, various inherent data values of the light guide plate are used. The inherent data values include the length (H, V) of the light guide plate in the x-axis and the y-axis, the cross-sectional area of the light guide plate (Sxy), and the light guide plate at the edges. Since there is a spare area of the light guide plate, the area that excludes the spare area and actually derives light is called a light emitting area, and the length of the light emitting area in the x- and y-axis (Lx, Ly) and the height of the light guide plate (V), the first pen pressure (m), which is the pressure to press the entire light guide plate during processing, the second pen pressure (m '), which is the pressing pressure at the part where the light guide plate is processed, the depth (d) of the reflective pattern to be processed, and the reflectance of the light guide plate. (R30) and (S30), one of the light guide plate models, the length of the light guide plate to the x-axis and y-axis, that is, H = 319.4mm, V = 245mm, the height of the light guide plate T = 6mm, in the case of LM157E2 The length of the x and y axes of H = 319 mm, V = 258.4 mm And the height T = 4mm of the light guide plate. Considering the density, particle size, and viscosity of the light guide plate When the light guide plate is processed with a standard pen pressure of 450g, the groove depth theoretically becomes 0.06mm. The following equations are used using correction factors in consideration of the error from the actual processing depth.

Among the eigen data mentioned above, the second pen pressure (m '= the pressure corresponding to the cross-sectional area where the processing tip and the light guide plate contact each other), the cross-sectional area Sxy of the light guide plate, the depth of the reflection pattern d, and the reflectance R of the light guide plate are as follows. It can be calculated by them.

m '= (1+ {m (pressure applied to the light guide plate = input pressure)-450g (reference pressure)} / reference pressure (450g)) * 0.000023 Equation (4)

Sxy = H * V Equation (5)

d = 2 * m '/ (m * pi (3.1415) * cos45) * Sxy * (T / 4) equation (6)

R = 1.35 * d equation (7)

Since the reflection factor R of the light guide plate calculated as described above and the number Nx of reflection patterns to be designed in the light guide plate in the x-axis direction have a relationship of equation (8), calculation is possible, and from there, The number Ny of reflection patterns to be designed can be calculated, which is equal to Equation (9) (S31).

Nx = 2 / R-1 Equation (8)

Ny = Nx * T / 5 * 0.9 Equation (9)

The number of reflection patterns to be designed on the light guide plate is calculated based on the calculated values. The next problem is how to arrange them, and the corresponding parameter is to obtain the distances Lx and Ly between the reflection patterns. This can also be solved by the equation, wherein the spacing between the reflection patterns in the x- and y-axis directions is determined by the line spacing trend function (fx, fy), and the coefficients (a, b) of the line spacing trend function are Any value that can vary depending on the situation.

Lx (n) = f [a ₀ , a ₁ , a ₂ ; n] Equation (10)

Ly (n) = g [b ₀ , b ₁ , b ₂ ; n] equation (11)

Where a ₀ , a ₁ , a ₂ , ... b ₀ , b ₁ , b ₂ , .... are constants, and Lx (n) and Ly (n) are functions of n.

First, Eq. (10) should be used to find the distance between reflection patterns on the x-axis. The coefficient a _k of Eq. (10) is set to an arbitrary value (S40) and n = 1, 2, 3,. When inputting up to Nx, the interval between each reflection pattern is calculated.

After the intervals between the Nx reflection patterns are calculated, all of them are added (S41) and the added values must be compared with Ly, which is the length in the y-axis direction in the above-described light emitting region (S42). Because each reflection pattern having the intervals calculated in the x-axis direction must be designed in the light emitting area, comparing these values is a very important process.

However, the light guide plate model of the LM151X2 uses 256, which is the number of reflection patterns in the x-axis direction minus 18, which is calculated by considering various environments that may occur during mass production, such as areas occupied by the reflection patterns. In equation (10), n = 1, 2, 3,... After substituting values up to 256, all the obtained function values are added, and the calculated value is compared with Ly, which is the y-axis length of the emission area.

As a result of the comparison, if the sum of the calculated total reflection patterns is larger than Ly, which is the y-axis length of the emission area, an error value corresponding to the difference value is detected (S44) and then adjusted by setting a, which is a coefficient of the line interval trend function. After that (S40), the above steps may be repeated until the sum of the intervals of the entire reflection patterns is equal to the y-axis length of the emission area (S40, S41, S42). If it is larger than the length value, the coefficient may be adjusted smaller. On the contrary, if the calculated sum is smaller than the length value of the light emitting area, the coefficient may be adjusted larger.

In addition, the distance between the reflection patterns with respect to the y-axis is also obtained using Equation (11), and b _k , which is a coefficient of Equation (11), is set to an arbitrary value (S40), and n = 1, 2, 3,... After calculating the sum of the intervals of the total reflection patterns calculated by sequentially inputting up to Ny (S41), and comparing the Lx, which is the length of the light emitting area on the x-axis (S43), the same process may be repeated. As in the case of the light guide plate model of the LM151X2, 296 is calculated by subtracting 4 from Ny = 300, which is the number of reflection patterns in the y-axis direction in consideration of various environments that may occur during mass production, such as areas occupied by the reflection patterns. And n = 1, 2, 3,... In equation (11). , The values up to 296 are substituted, and all the obtained function values are added, and the calculated values are compared with Lx, which is the x-axis length of the light emitting area.

In this way, if the sum of the calculated intervals between the reflection patterns is equal to both the length values in the light emitting area for both the x and y axes (S42, S43), the line interval tendency function is completed by the coefficient set at this time, and is completed. N = 1, 2,... After substituting, n, a reflection pattern having respective intervals calculated therefrom may be designed for each of the x and y axes (S45).

Meanwhile, FIG. 6A further includes a reflecting plate 12 as shown in FIG. 1 in a light guide plate having a bidirectional reflective pattern according to the present invention, so that light incident from the outside is caused by the light guide plate 100 and the reflecting plate 12. FIG. 6B is a table showing the luminance value of the light derived after being reflected, which corresponds to a 15-20% improvement in luminance derived from the light guide plate as compared with the conventional art. FIG. 6C further includes a reflecting plate 12 as shown in FIG. 1 and two diffuser plates 13 as shown in FIG. 1 in a light guide plate designed with a bidirectional reflective pattern in accordance with the present invention, and further includes a prism on the diffuser plate 13. 6D is a graph showing the table of FIG. 6C, which corresponds to a 6-15% improvement in luminance derived from the LGP.

The light guide plate and the pattern design method of the light guide plate of the side light type backlight device according to the present invention constructed and configured as described above are designed so that the distance between the reflective patterns designed on the light guide plate is consistently formulated so as to be consistently arranged. In addition, the luminance value of the light derived from the light guide plate is uniform throughout to meet the original purpose of the light guide plate, and the luminance value of the derived light is increased to increase the light reflectivity of the light guide plate, thereby achieving high efficiency.

In addition, in the light guide plate according to the present invention designed as described above, 192 * 310 reflection patterns are designed, which reduces the production time by about 46 differences in the number of lines when compared to the conventional 255 * 293 reflection patterns. It is a very efficient invention.

Claims (12)

delete delete While having a predetermined distance in one direction, the pattern of the V-shaped unevenness processed by the vcutting method is arranged, The predetermined separation distance is calculated by dividing the light guide plate having the same distance in one side direction into a unit area having a split surface parallel to the incident surface of light and having the same width, and calculating a reflectance for each area in the divided unit area. A light guide plate of a side light type backlight device, characterized by varying the number of reflection patterns to be designed in each unit area by reflectance. delete delete In the method of pattern designing a side light type light guide plate by a breaking method, A first step of dividing an area in the light guide plate into a predetermined unit area having a dividing plane parallel to the incident plane of light and having the same width; Calculating a reflectance for each region in the divided unit region; And And a third step of varying the number of reflection patterns to be designed in each unit area by the calculated reflectance. delete The method of claim 6, The pattern design method of the light guide plate, characterized in that the calculated reflectance for each unit region and the number of reflection patterns set in each unit region is inversely related. The method of claim 6, The pattern design method of the light guide plate characterized in that the luminance value of the light derived from each reflection pattern is uniform regardless of the unit area. delete In the method of pattern-designing the side light-type light guide plate by the breaking method, A first step of measuring initial values inherent to the light guide plate; A second step of setting the number of lines of parallel reflection patterns, respectively, by the measured initial values; Calculating a separation distance between lines from the set number of lines; A fourth step of comparing the calculated sum of the separation distances with a predetermined reference value; And And a fifth step of variably adjusting the separation distance based on the comparison result. The method of claim 11, The light guide plate has a vertical length value corresponding to the length of the light guide plate in a direction perpendicular to the line of the reflective pattern, The reference value of the fourth step is the pattern design method of the light guide plate, characterized in that the vertical length value.