CN100381914C - Microstructure of light guide plate - Google Patents

Abstract

The invention discloses a microstructure of a light guide plate, wherein the light guide plate comprises a light inlet surface, a light outlet surface and a bottom surface, the microstructure is arranged on the bottom surface of the light guide plate, the microstructure is formed by intersecting a concave recess inwards the light searching plate with the light guide plate, the microstructure comprises a light reflecting surface, the light reflecting surface is arranged between the light inlet surface and the light outlet surface, an angle theta is formed between the light reflecting surface and the bottom surface of the light guide plate, the shape of the light reflecting surface is an arc quadrangle or a fan shape by the depression of the light outlet surface, the arc quadrangle is provided with two parallel arc edges, the arc lines of the two arc edges are concentric, and the path of light can be.

Description

Microstructure of light guide plate

technical field

The invention relates to a microstructure of a light guide plate, which is applied to a backlight module of a liquid crystal display.

Background technique

Please refer to FIG. 1 , which is a schematic diagram of a microstructure 2 of a conventional light guide plate 1, which produces a microstructure 2 with a rough surface on the bottom surface 12 of a smooth light guide plate 1 by etching, and an incident light 50 enters the surface of the microstructure 2. That is, scattered reflected light rays 51 or refracted light rays 52 are produced. When the angle of incidence of the reflected light 51 incident on the light-emitting surface 11 of the light guide plate 1 is less than the critical angle, it exits the light-emitting surface 11 of the light guide plate 1; if the incident angle is greater than the critical angle, the reflected light 51 is totally reflected back into the light guide plate 1 and Keep passing.

FIG. 2 explains the coordinates of FIG. 3 a . FIG. 3 a is a radar diagram of light intensity emitted from the light emitting surface 11 of the conventional light guide plate 1 . The abscissa represents the horizontal angle (HarizOntal angle, HA), and the movement of the angle is from the normal direction 13 of the light-emitting surface 11 to the direction 14 perpendicular to the light source 4; the ordinate represents the vertical angle (Vertical angle, VA), and the movement of the angle is from the light-emitting The normal direction 13 of the surface 11 turns to a direction 15 parallel to the light source 4 . In Fig. 3a, each closed curve represents a light intensity value, which is defined as the luminous flux per unit solid angle. There are 10 closed curves in this figure, representing 10 levels of light intensity. It can be seen from FIG. 3a that the light intensity distribution of light emitted from the conventional light guide plate 1 is approximately Lambertian distribution (LambertiandistributiOn), that is, a circular closed curve is generated in FIG. 3a, and the light intensity distribution presents a cosine function. The light intensity is converted into a luminance value, that is, the luminance is equivalent in all directions.

Please refer to FIG. 3 b , which is a perspective view of the light output intensity of the light output surface 11 of the conventional light guide plate 1 . The light intensity distribution is approximately spherical, that is, close to the Lamberson distribution. This figure can be used to observe the changes of the light intensity at various angles or directions.

In addition, the light guide plates of Taiwan Patent No. 575759, U.S. Patent No. 6629764 and No. 6755545 are all implemented with linear light sources, and the light emitting surfaces of the latter two are wave-shaped, and the microstructures disclosed by the three are all natural. The bottom surface of the light guide plate is in the shape of a concave pyramid. Among them, Taiwan Patent No. 575759 is a semi-conical or triangular cone. Similar to a capital M, and the disclosed example includes a sloped bottom surface, and US Pat. No. 6,755,545 has a single pyramid shape.

On the whole, the reflected light of the pyramid-shaped inner hollow structure is easier to scatter rather than concentrate.

Contents of the invention

The purpose of the present invention is to provide a microstructure of the light guide plate, which can increase the output intensity of light from the light-emitting surface of the light guide plate, so as to increase the luminance of the light guide plate.

For realizing the above object, technical solution of the present invention is:

A microstructure of a light guide plate, the light guide plate includes a light incident surface, a light exit surface, and a bottom surface, light from a light source enters the light guide plate from the light incident surface, and exits the light guide plate from the light exit surface, and the bottom surface is located on the opposite surface of the light exit surface, The microstructure is arranged on the bottom surface, and the microstructure is formed by intersecting the light guide plate with a concave depression inwardly toward the light guide plate. An angle θ is included; and the shape of the light reflecting surface is viewed as a curved quadrilateral from the light-emitting surface. The curved quadrilateral has two parallel curved sides, and the arcs of the two curved sides are concentric. The shape of the light reflecting surface can also be fan-shaped when viewed from the light emitting surface.

The microstructure of the light guide plate further includes: a rear light-transmitting surface, adjacent to the light-reflecting surface, relatively far from the light-incident surface of the light-guiding plate, and perpendicular to the bottom surface of the light-guiding plate; two light-transmitting surfaces , adjacent to the two sides of the light reflection surface, and perpendicular to the bottom surface of the light guide plate; and a hollow surface, which is the concave part of the bottom surface of the light guide plate.

The light reflection surface is taken out from a cross-section cone with a wide top and a narrow bottom. The center point of the cross-section cone is close to the light incident surface. The cutting range cuts an angle β from the center point of the cross-section cone, and cuts out a light reflection surface with a central angle of β. .

The light reflection surface is taken out by an elliptical cone with a wide top and a narrow bottom. The center point of the elliptical cone is close to the light incident surface. The cutting range cuts an angle β from the center point of the cone, and cuts out the light with a central angle of β. Reflective surface.

The light reflecting surface is taken out from a cross-sectional cone with a narrow top and a wide bottom. The center point of the cross-section cone is close to the rear light-transmitting surface. noodle.

The light reflecting surface is taken out from an elliptical cone with a narrow top and a wide bottom. The center point of the elliptical cone is close to the light-transmitting surface. The cutting range cuts an angle β from the center point of the elliptical cone, and the central angle of the cut out circle is β. light reflective surface.

The shape of the side section of the light reflecting surface can be a straight line, a concave curve or a convex curve.

After adopting the above scheme, due to the microstructure of the bottom surface of the light guide plate of the present invention, its shape is an arcuate quadrilateral or fan-shaped depression concaved from the bottom surface of the light guide plate, and the light reflection surface can change the path of light, thereby effectively reflecting and partially Concentrate the light, and increase the intensity of light emitted from the light-emitting surface of the light guide plate, thereby increasing the brightness of the light guide plate.

Description of drawings

1 is a schematic diagram of a conventional microstructure of a light guide plate;

FIG. 2 is a schematic diagram of light emitting from the light emitting surface of a conventional light guide plate (also illustrating the coordinate axes in FIG. 3 );

Fig. 3a is a radar diagram of the light output intensity of the light output surface of the conventional light guide plate;

Fig. 3b is a three-dimensional view of the light output intensity of the light output surface of the conventional light guide plate;

4 is a schematic diagram of the first example of the microstructure of the present invention arranged on the light guide plate;

Figure 5a is a structural diagram of the first example of the microstructure of the present invention;

Fig. 5b is a top view of the first example of the microstructure of the present invention;

Fig. 5c is a sectional view of the first example of the microstructure of the present invention;

Fig. 6a is a schematic diagram illustrating that the light reflecting surface is taken on a cross-sectional conical surface to assist in explaining the present invention;

Fig. 6b is a side view of the present invention to assist in explaining that the light reflecting surface is taken on the cross-sectional conical surface;

Fig. 7 is a schematic diagram of the light-transmitting surface taken from a cylindrical surface after the auxiliary description of the present invention;

Figure 8a is a schematic diagram of the transmission behavior of light in the microstructure;

Figure 8b is a side view of light transmission behavior 1 in the microstructure;

Figure 8c is a side view of light transmission behavior 2 in the microstructure;

Figure 8d is a schematic diagram of light transmission behavior 3 in the microstructure;

Fig. 8e is a front view of light transmission behavior 3 in the microstructure;

Fig. 9a is a radar diagram of the light output intensity of the light output from the light guide plate of the first example of the microstructure of the present invention;

Fig. 9b is a perspective view of the light output intensity of the light output from the light guide plate of the first example of the microstructure of the present invention;

Fig. 10 is a structural diagram of the second example of the microstructure of the present invention;

Fig. 11 is a structural diagram of the third example of the microstructure of the present invention;

Fig. 12 is a structural diagram of the fourth example of the microstructure of the present invention;

Fig. 13 is a top view of the microstructure distribution of the fifth example of the microstructure of the present invention;

Fig. 14 is a side view of the microstructure distribution of the sixth example of the microstructure of the present invention;

Fig. 15 is a side view of the microstructure distribution of the seventh example of the microstructure of the present invention;

16 to 21 are top views of the first example of the present invention, where the microstructures of the present invention are distributed on the light guide plate.

Explanation of main component symbols

1, 1A, 1A1, 1A2, 1A3, 1A4, 1A5, 1C, 1D light guide plate

10A Light-incoming side 11, 11A Light-emitting side

12, 12A Bottom surface 13 Normal direction of light-emitting surface

14 Direction perpendicular to light source 15 Direction parallel to light source

2 Microstructure 3 Reflector

4 Linear light source 50 Incident light

51 Reflecting Rays 52 Refracting Rays

6, 61, 6A, 6B, 6C, 6D, 6E, 6F Microstructure

601, 601A, 601B, 601C, 601D, 601E, 601F Light reflective surface

602, 602A, 602B rear light-transmitting surface

603, 604, 603A, 604A, 603B, 604B, 603C, 604C, 603D, 604D side transparent surface

605, 605A, 605B, 605C hollow surface

701 Centerline

702, 703, 702A, 703A, 702D, 703D cutting wire

704 The direction of the line from the center of the cone to the incident point

705 The normal direction of the light reflecting surface

8 Pointing to β Central Angle

θ Elevation Angle h Height

r1 arc radius r2 arc radius

α incident angle

Detailed ways

Please refer to FIG. 4 , which is a schematic diagram of the microstructures 6 arranged on the light guide plate 1A according to the first example of the present invention. Wherein the light is injected into the light-incident surface 10A of the light guide plate 1A by the light source 4, and the microstructure 6 is arranged on the bottom surface 12A of the light guide plate 1A and is an arc-shaped depression concave inward, and can make the light exit the light-emitting surface 11A to improve the light guide. Brightness of light panel 1A.

Please refer to FIG. 5 , which is a structural diagram, a top view and a cross-sectional view of the microstructure 6 . The microstructure 6 is an arc-shaped depression, which includes a light reflection surface 601 , a rear light transmission surface 602 , side light transmission surfaces 603 , 604 and a hollow surface 605 . The light reflecting surface 601 is a fan-shaped curved surface. Please also refer to FIG. 6 for illustration. The light reflecting surface 601 is an arc-shaped curved surface taken out after cutting along two imaginary lines 702 and 703 on a conical section, and the height of the conical section is h. The distance from the center O of the cone to the front periphery of the light reflecting surface 601 is r1, and the distance from the center O of the cone to the rear periphery of the rear light-transmitting surface 602 is r2. Please refer to FIG. 5 b , the cutting range cuts an angle β from point O at the center of the cross-sectional cone. The direction from the center line 701 to the light reflecting surface 601 is referred to as the direction 8 of the microstructure 6 . The side transparent surfaces 603 , 604 are cross-sections cut by cutting lines 702 , 703 . The rear light-transmitting surface 602 is an arc-shaped curved surface. Please refer to FIG. 7 for illustration. The rear light-transmitting surface 602 is an arc taken out after cutting along two dotted lines 702 and 703 on a cylindrical surface with a radius of r2 and a height of h. Shaped surface, the center of the cylinder is at the same position as the center of the above-mentioned cone. The hollow surface 605 is an arc, which is the notch formed by the microstructure 6 on the bottom surface 12A of the light guide plate 1A. Please refer to Figure 5b, no matter from the a-a section, a'-a' section or a"-a" section, you can see the cross-sectional view of the microstructure 6 in Figure 5c, this is because the light reflecting surface 601 is from the cross-sectional cone A part of the surface is taken out, and the rear light-transmitting surface 602 is a part taken out of the cylindrical surface, so the three cross-sectional views are the same, and the light reflection surface 601 and the bottom surface 12A of the light guide plate 1A (the hollow surface 605 in the figure) form an angle θ, The angle θ can control the change of the light reflecting surface 601 and affect the transmission behavior of the light in the microstructure 6 .

Please refer to FIG. 8 , which is a schematic diagram of light passing through the microstructure 6 . The light transmits in any direction in front of the microstructure 6, and because the microstructure 6 forms an arc, the light path of the outgoing light generally does not change much after the light from each direction passes through the microstructure. Please refer to Fig. 8a and Fig. 8b, when the direction of the incident light 50 is close to the connection direction 704 from the cone center O point to the incident point, the incident light 50 hits the light reflecting surface 601 of the microstructure 6, and its incident angle α is greater than The critical angle of the light guide plate 1A is 42° (the refractive index of the light guide plate is 1.49), and it is reflected upward, thereby increasing the intensity of light emitted toward the normal direction 13 . Referring to FIG. 8c, when the incident angle α of the incident light 50 is smaller than the critical angle 42° of the light guide plate 1A, the light will pass through the first microstructure 6, pass through the rear light-transmitting surface 602 to the second microstructure 61, and then pass through the second microstructure 61. Reflection (reflection light 51 ) or transmission is performed on the second microstructure 61 . The above two light transfer behaviors can increase the light intensity in the HA direction.

Please refer to FIG. 8d and FIG. 8e, when the direction of the incident light 50 is far from the direction 704 connecting the point O from the center of the cone to the incident point, the incident light 50 reaches the light reflecting surface 601 and bounces sideways (reflected light 51) , this light transfer behavior can increase the light intensity in the VA direction.

Please refer to FIG. 9 , which is a light intensity distribution diagram of the light emitted from the light guide plate 1A having the microstructure 6 of the first example of the present invention. This figure shows that after the light enters the light guide plate 1A with the microstructure 6 from the light source 4, it contacts the microstructure 6 and transmits to the light output direction 13, and the light output angle is mainly concentrated at HA=25°, VA=3°. It can be seen that the elevation angle of the microstructure 6 θ can change the light angle and light distribution of the light in the HA direction, and the central angle β can control the light distribution in the VA direction.

Please refer to FIG. 10 , which is a structural diagram of the microstructure 6A of the second example of the present invention. The microstructure 6A is a fan-shaped structure, which still includes a light-reflecting surface 601A, a rear light-transmitting surface 602A, side light-transmitting surfaces 603A, 604A, and a hollow surface 605A. The light-reflecting surface 601A is a fan-shaped curved surface taken from a sharp cone.

Please refer to FIG. 11 , which is a structural diagram of the microstructure 6B of the third example of the present invention. The microstructure 6B is an arc-shaped depression, and the space formed by the arc-shaped depression includes a light-reflecting surface 601B, a rear light-transmitting surface 602B, side light-transmitting surfaces 603B, 604B, and a hollow surface 605B. The light-reflecting surface 601B is an arc-shaped curved surface, and the light reflecting surface 601B of the microstructure 6B of this example protrudes toward the light guide plate 1C. Looking from the light guide plate 1C to the hollow surface 605B, the light reflection surface 601B of the microstructure in this example is taken out from a conical section with a narrow top and a wide bottom, while the light reflection surface 601 of the microstructure 6 in the first example is taken from a wide top and narrow bottom section. Take out the cone.

Please refer to FIG. 12 , which is a structural diagram of the microstructure 6C of the fourth example of the present invention. The microstructure 6C is a fan-shaped structure, including a light reflection surface 601C, side light-transmitting surfaces 603C, 604C, and a hollow surface 605C. The light reflection surface 601C is a fan-shaped curved surface, and the light reflection surface 601C of the example microstructure 6C is directed The Light Panel 1D stands out. The microstructure 6C of this example is taken from a pointed cone, so there is no rear light-transmitting surface.

Please refer to FIG. 13 , which is a top view of the microstructure 6D of the fifth example of the present invention. Viewed from above, the light reflecting surface 601D is in the shape of an elliptical arc or a fan. Cutting lines 702D, 703D draw side light-transmitting surfaces 603D, 604D outward from the focal point of the ellipse, and are perpendicular to the tangent of the ellipse.

Please refer to FIG. 14 , which is a side view of the microstructure 6E of the sixth example of the present invention, and the light reflecting surface 601E is a convex curve viewed from the side. Please refer to FIG. 15 , which is a side view of the microstructure 6F of the seventh example of the present invention, and the light reflecting surface 601F is a concave curve viewed from the side.

Compared with the first example, the above-mentioned second to seventh examples have different distributions of light transmission due to the different curved surfaces taken from the light reflection surface 601 and 601A-601F. The transfer behaviors of 6A-6F are similar, that is, they all increase the luminance and uniformity of the light guide plate.

Please refer to FIG. 16 to FIG. 21 , which take the first example of the present invention as an example to illustrate the top views of the microstructures distributed on the light guide plate. Fig. 16 is the top view of Fig. 4, the microstructures 6 are regularly distributed on the light guide plate 1A, and the points 8 of all the microstructures 6 are all in the same direction, and they are facing the direction of the linear light source 4, so as to facilitate light entering into the microstructures to generate Brightening phenomenon.

Please refer to FIG. 17 , the microstructures 6 are regularly distributed on the light guide plate 1A1, but all the microstructures 6 point 8 not in the same direction, but overall, the microstructures 6 tend to be in the direction of the linear light source 4 , so as to facilitate the light to enter the microstructure to produce a brightening phenomenon.

Please refer to FIG. 18 , the microstructures 6 present a random number distribution on the light guide plate 1A2, and the points 8 of all the microstructures 6 are all facing the same direction, and facing the direction of the linear light source 4, so as to facilitate light entering into the microstructures to generate brightness enhancement. Phenomenon.

Please refer to FIG. 19 , the microstructures 6 present a random number distribution on the light guide plate 1A3, but all the microstructures 6 point 8 are not in the same direction, but overall, the microstructures 6 tend to be in the direction of the linear light source 4 , so as to facilitate the light to enter the microstructure to produce a brightening phenomenon.

Please refer to FIG. 20 , the microstructures 6 are regularly distributed on the light guide plate 1A4 , and all the microstructures 6 point 8 all or partly toward the point light source 41 , so as to facilitate light entering into the microstructures to produce brightness enhancement.

Please refer to FIG. 21 , the microstructures 6 are randomly distributed on the light guide plate 1A5, and all or part of the directions 8 of the microstructures 6 are directed towards the point light source 41, so as to facilitate light entering into the microstructures to produce brightness enhancement.

In FIGS. 16 to 21 , the microstructure 6 can adopt one of the above-mentioned examples, or mix the microstructures of two or more examples. The distribution of the microstructures in the above example is favorable for the light to enter the microstructures to produce a brightening phenomenon to increase the luminance, and to make the light guide plate produce light with a high uniformity surface.

As mentioned above, according to the present invention, the luminance and uniformity of the light guide plate can be improved, the display performance of the liquid crystal display can be improved, and the power consumption of the display can be saved. Now that the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (4)

1. A microstructure of a light guide plate, the light guide plate includes a light incident surface, a light exit surface, a bottom surface and a light reflection surface, the light of the light source enters the light guide plate from the light incident surface, and exits the light guide plate from the light exit surface, and its bottom surface is located at On the opposite surface of the light-emitting surface, the microstructure is arranged on the bottom surface, and the microstructure is formed by intersecting the light-guiding plate with a depression concave inward; the light-reflecting surface is between the light-incident surface and the light-emitting surface, and The bottom surface of the light guide plate forms an angle θ, and the shape of the light reflecting surface is viewed as an arc quadrilateral or a fan from the light-emitting surface. The arc quadrilateral has two parallel arc sides, and the arc lines of the two arc sides are the same The center of a circle; characterized by: Cut out a fan shape with a central angle of β from the side expansion view of a cone, and the light reflection surface is a part taken from the side of the fan shape away from the center of the fan shape to form a cone with a wide top and a narrow bottom. The arc-shaped curved surface of the three-dimensional shape, wherein the center of the sector is close to the light incident surface. 2. The microstructure of the light guide plate as claimed in claim 1, characterized in that it further comprises: a rear light-transmitting surface, adjacent to the light reflection surface, and the relative light reflection surface is far away from the light incident surface of the light guide plate, and with The bottom surface of the light guide plate is vertical; the two light-transmitting surfaces are adjacent to the two sides of the light reflection surface and are perpendicular to the bottom surface of the light guide plate; 3 . The microstructure of the light guide plate according to claim 1 , wherein the shape of the side cross-section of the light reflection surface is a concave curve. 4 . 4 . The microstructure of the light guide plate according to claim 1 , wherein the shape of the side cross-section of the light reflecting surface is a convex curve.

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