Light guide panel having lenticular lens and Back light apparatus using thereof

专利摘要:
PURPOSE: A light guide panel with a lenticular lens and a back light device using the same are provided to loose the local darkness generated when light emitted from spot light sources is guided to a light guide panel by forming lenticular lenses, thereby improving the uniformity in the luminance and reducing the dark areas of the light guide panel. CONSTITUTION: A light guide panel(301) using spot light sources(302) as light sources includes lenticular lenses(303) formed in the shape of concave and convex on a light incident surface. The lenticular lenses are formed of a series of triangular convex portions with a same pitch. An LCD back light device includes the spot light sources mounted to the light incident surface at a sectional side of the light guide panel and the lenticular lenses are formed on the light incident surface of the light guide panel.
公开号:KR20030043257A
申请号:KR1020010074335
申请日:2001-11-27
公开日:2003-06-02
发明作者:전종원；박억병
申请人:주식회사 흥진메텍；
IPC主号:

专利说明:

Light guide panel having lenticular lens and backlight device using same
[13] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate used for a backlight of a liquid crystal display device and a backlight device using the same. Specifically, a backlight device is formed by forming a lenticular lens on one side of a light guide plate used in a backlight device using a point light source as a light source. The present invention relates to a structure of a light guide plate capable of minimizing blind spots and improving luminance uniformity, and to a backlight device having such a light guide plate.
[14] Generally, a liquid crystal display device includes a liquid crystal panel 102 including a liquid crystal panel (not shown) enclosed between a TFT substrate 102a and a color filter substrate 102b and two substrates 102a and 102b. It is composed of a backlight unit located at the rear of the liquid crystal panel 102 to provide light (see FIG. 1).
[15] The backlight unit includes a light source 104 that emits light, a light guide plate 105 through which light emitted from the light source 104 is incident, and a reflection plate positioned at a rear surface of the light guide plate 105 to reflect light to the front surface of the light guide plate 105 ( 106 and an optical film plate 107 which serves to stably transmit the light emitted from the light guide plate 105 to the liquid crystal panel 102.
[16] In addition, the liquid crystal panel 102 and the backlight unit are wrapped and fixed by the mold frame 101 and the top chassis 103.
[17] On the other hand, the light source 104 is located in parallel to one side of the light guide plate, a line light source consisting of a cold cathode tube lamp is generally used as shown in the figure.
[18] Recently, however, a liquid crystal display device is often used in a personal information communication terminal such as a mobile phone or a personal digital assistant (PDA). Due to the characteristics of a portable device, a liquid crystal display device used in such a portable personal information communication terminal is used. The backlight system mounted on the thinner, lighter and lower power consumption is preferred. Therefore, in a backlight system of a liquid crystal display device mounted on such a portable personal information communication terminal, a point light source such as a light emitting diode (LED) chip is more preferred than a line light source such as a cold cathode tube lamp.
[19] On the other hand, the uniformity of the image quality within the screen of the display device is very important due to the display characteristics of the display device. The uniformity of the image quality in the liquid crystal display device eventually determines the luminance uniformity of the backlight device. However, as will be described below, in the conventional backlight device using a point light source, there is a limit in which a dark part, that is, a substantial part of the blind spot exists.
[20] 2A and 2B are schematic plan views showing the point light source arrangement of the backlight device according to the related art and the light incident form of the light guide plate, respectively.
[21] Light emitted from the point light source 202 is incident on the light guide plate 201 with a predetermined incident angle θ and ultimately directed to a liquid crystal panel (not shown). Here, since the light efficiency and the display characteristics of the liquid crystal display are closely related to the light guide plate incident efficiency of the light source, it is important that the light emitted from the light source is uniformly incident on the entire light guide plate.
[22] However, when using a single point light source in the backlight device according to the prior art, as shown in Figure 2a, the point light source 202 is located in the center in contact with one side of the light guide plate 201, the point light source Due to the light propagation angle range θ from the left and right of the point light source 202 located in the center, the area that remains dark in the dark state, that is, the square 203 is necessarily present. When the light emitted from the point light source 201 is expressed to the light guide plate 201 is expressed as follows.
[23]
[24] Here, θ refers to the angle range in which the light from the point light source proceeds in the light guide plate, and n is the refractive index of the light guide plate. In general, a light guide plate made of PMMA (Polymethyl methacrylate) material used as a material of the light guide plate has a refractive index of 1.49, and a traveling angle range (θ) thereof is 84.31 °.
[25] Therefore, dark squares 203 exist in the light source, i.e., the area of about 48 ° to the left and right of the point light source. Such blind spots not only lower the display quality of the liquid crystal display device but also lower the luminance uniformity, thereby degrading the function of the liquid crystal display device.
[26] In order to solve this problem, as shown in FIG. There is bound to be a blind spot (204). Although it is possible to form a predetermined shape or pattern on the lower surface of the light guide plate 201 to slightly improve the darkness of the blind spots, it is difficult to obtain satisfactory results. In addition, although a method of arranging a larger number of point light sources may be considered, an increase in the number of point light sources may not only increase costs but also increase power consumption, and thus may not be a proper solution.
[27] The present applicant has already filed an invention relating to an arrangement structure of a point light source in a backlight device (Patent Application No. 2001-53343) as a solution for solving the above problems, and in addition to the invention described herein We propose another solution by suggesting.
[28] The present invention was developed to solve the above problems in the backlight structure using a point light source as a light source, the present invention is to change the structure of the light guide plate of the backlight device itself to minimize the blind spot and improve the luminance uniformity. To provide a light guide plate that can be made.
[1] 1 is an exploded perspective view of a general liquid crystal display device.
[2] 2A and 2B are plan views schematically illustrating a point light source arrangement form of a backlight device according to the related art and a light incidence form of a light guide plate according to the related art;
[3] 3A is a plan view schematically illustrating a light guide plate structure according to a first embodiment of the present invention;
[4] FIG. 3B is a perspective view showing three-dimensionally FIG. 3A;
[5] 4A is a view showing an angle between a light entering surface of a light guide plate according to the prior art and a traveling direction of light.
[6] Figure 4b is a view showing the angle between the light entering surface of the light guide plate and the traveling direction of the light guide plate according to the first embodiment of the present invention and the angle of incidence at the uneven portion.
[7] 5 conceptually illustrates that light is incident on the light guide plate according to the first embodiment of the present invention and scattered into the light guide plate.
[8] 6A is a perspective view of a light guide plate according to a second embodiment of the present invention.
[9] 6B is a perspective view of a light guide plate according to a third embodiment of the present invention.
[10] <Explanation of symbols for the main parts of the drawings>
[11] 301: light guide plate 302: point light source
[12] 303: lenticular lens
[29] In order to achieve the above object, in the present invention, as a light guide plate provided in a backlight device of a liquid crystal display device using a point light source as a light source, a lenticular lens having an uneven shape is formed on a light incident surface of the light guide plate on which light from the light source is incident. There is provided a light guide plate of a backlight device.
[30] In the present invention, the lenticular lens of the concave-convex shape formed on the light incident surface of the light guide plate is composed of a plurality of triangular convex portions, and the triangular convex portion has a constant shape in the thickness direction of the light guide plate. The triangular convex portion may be continuously formed over the entire light incident surface of the light guide plate.
[31] According to a specific embodiment of the present invention, in the triangular lenticular lens, it is preferable that the vertices of the triangular convex portions form a right angle.
[32] On the other hand, according to another embodiment of the present invention, the lenticular lens of the concave-convex shape formed on the light incident surface of the light guide plate may be composed of a plurality of semi-circular or elliptical convex portion or concave portion. Also in this case, the semicircular or elliptical convex portion or concave portion has a constant shape in the thickness direction of the light guide plate. In addition, the semi-circular or elliptical convex portion or concave portion may be continuously formed over the entire incident surface of the light guide plate.
[33] As described above, the light guide plate of the present invention having a lenticular lens formed on a light incident surface has a light emitted from a point light source through the lenticular lens and is irradiated to the light guide plate, thereby providing uniform luminance inside the light guide plate, thereby causing problems in the conventional light guide plate. It is possible to minimize the blind spots.
[34] In addition, the present invention provides a backlight device having a light guide plate on which a lenticular lens is formed as a backlight device used in a liquid crystal display device.
[35] Hereinafter, the light guide plate of the present invention will be described in detail with reference to the accompanying drawings.
[36] 3A is a plan view schematically illustrating a light guide plate structure according to a first embodiment of the present invention, FIG. 3B is a perspective view three-dimensionally illustrating FIG. 3A, and FIG. 4A is a light incident surface and a light traveling direction of a light guide plate according to the related art. 4B is a view showing an angle between the light incident surface and the light traveling direction of the light guide plate according to the first embodiment of the present invention, and an incident angle at the uneven portion.
[37] As shown in the figure, a point light source 302 is disposed on one side of the light guide plate 301. In the light guide plate 301 according to the present invention, the light from the point light source 302 is incident of the light guide plate 301. An uneven lenticular lens 303 is formed on the light incident surface (see FIGS. 3A and 3B).
[38] 3A and 3B, the lenticular lens 303 having a concave-convex shape formed on the light incident surface of the light guide plate has a shape in which triangular convex portions are continuously formed. In other words, in the illustrated embodiment, the lenticular lens 303 has a continuous sawtooth shape at an angle. The triangular convex portion of the lenticular lens 303 has a constant shape in the thickness direction of the light guide plate (see FIG. 3B). In addition, the pitch of the said triangular convex part is the same.
[39] In the present invention, since the light incident surface of the light guide plate 301 is composed of the lenticular lens 303 having an uneven shape as described above, when the light emitted from the light source 302 is incident on the light incident surface of the light guide plate, Since the angle θ _{2 in the} advancing direction approaches a right angle, it is possible to provide uniform luminance to the entire light guide plate.
[40] This is because in the case of the light incident surface 403 of the light guide plate 401 without the unevenness of the light, as the angle between the light incident surface 403 and the traveling direction of the light moves away from the light source 402, the light becomes smaller as the angle θ ₁ decreases. Compared with the weakening of the strength of the present invention, the effect of the present invention of improving the luminance uniformity as described above is clearly seen.
[41] In addition, the light incident surface is composed of the lenticular lens 303 of the concave-convex shape as described above, so that light is refracted by the inclined surface of the convex portion 303a when light emitted from the light source 302 is incident on the convex portion 303a. Since it is evenly spread to the inside of the light guide plate, it is possible to significantly reduce the rectangular portion formed in the light guide plate (see FIGS. 4A and 4B). Light refracted through the lenticular lens 303 is emitted to the light emitting surface of the light guide plate 301 according to a predetermined pattern formed under the light guide plate 301.
[42] As mentioned above in connection with the prior art, in the case of a polymethyl methacrylate (PMMA) material, which is generally used as a material of a light guide plate, its refractive index (n) is 1.49, and thus the traveling angle range (θ) is about 84.31 °. to be. Therefore, when considering the angle of incidence according to the material of the light guide plate, when the lenticular lens 303 formed on the light incident surface of the light guide plate 301 is formed in the shape of a saw tooth having a continuous triangular convex portion as described above, the vertex of the triangular convex portion is perpendicular to each other. It is preferable that it consists of.
[43] On the other hand, the squares inevitably exist by the first embodiment of the present invention as described above can be compensated by using the pattern design of the light guide plate, etc., the pattern design because the rectangular range is reduced in the light guide plate of the present invention than the conventional case Can be carried out more easily.
[44] In the present invention, the shape of the lenticular lens formed on the light incident surface of the light guide plate is not limited to the triangular convex portion described above, and may be modified to have a different shape.
[45] For reference, FIG. 5 conceptually illustrates that light is incident on the light guide plate according to the first embodiment of the present invention and scattered into the light guide plate.
[46] 6A and 6B are perspective views according to the second and third embodiments of the present invention, respectively.
[47] In the embodiment shown in FIG. 6A, the lenticular lens 303 formed on the light incident surface of the light guide plate is composed of elliptical or hemispherical convex portions. The oval or hemispherical convex portion has a constant shape in the thickness direction of the light guide plate. In addition, the elliptical or hemispherical convex portion may be continuously formed on the entire incident surface of the light guide plate.
[48] Meanwhile, in the third embodiment of the present invention illustrated in FIG. 6B, the lenticular lens 303 is formed of an elliptical or hemispherical recess.
[49] As described above, in the case of the lenticular lens 303 having an elliptical or hemispherical convex portion or a concave portion, as in the case of the lenticular lens composed of the triangular convex portions described above, the operations such as the right angle of the light and the incident surface and the minimization of the square of the uneven portion are It will be repeated, the repeated description thereof will be omitted.
[50] The light guide plate and the backlight device using the same according to the present invention form a lenticular lens made of convex or convex portions having irregularities on the light incident surface of the light guide plate to alleviate local darkness generated when light from a point light source enters the light guide plate, thereby reducing luminance. In addition to improving the uniformity, the area occupied by the dark portion in the light guide plate can be substantially reduced.
[51] Therefore, the pattern design of the light guide plate can be more easily performed, and thus, the brightness uniformity of the liquid crystal display device can be increased by mounting the light guide plate to the backlight device to configure the liquid crystal display device.

权利要求:
Claims (5)
[1" claim-type="Currently amended] A light guide plate for use in a backlight device of a liquid crystal display device using a point light source as a light source, wherein a light guide plate having an uneven shape lenticular lens is formed on a light incident surface of a light guide plate on which light from the light source is incident.
[2" claim-type="Currently amended] The light guide plate according to claim 1, wherein the lenticular lens of the concave-convex shape is composed of convex portions or concave portions having a plurality of triangular, semi-elliptical or hemispherical shapes and having a constant shape in the thickness direction of the light guide plate.
[3" claim-type="Currently amended] The light guide plate according to claim 2, wherein the lenticular lens of the concave-convex shape is composed of convex portions formed of a plurality of triangles having a predetermined shape in the thickness direction of the light guide plate, and vertices of the triangular convex portions are formed at right angles.
[4" claim-type="Currently amended] As a backlight device of a liquid crystal display device,
And a light guide plate and a point light source provided on the short-side light incident surface of the light guide plate,
And a lenticular lens having an uneven shape is formed on a light incident surface of the light guide plate on which light from the point light source is incident.
[5" claim-type="Currently amended] The backlight device according to claim 4, wherein the uneven lenticular lens formed on the light guide plate has a plurality of triangular, semi-elliptical or hemispherical shapes and has convex portions or concave portions having a constant shape in the thickness direction of the light guide plate.

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同族专利:

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公开号 | 公开日

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引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
2001-11-27|Application filed by 주식회사 흥진메텍

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2001-11-27|Priority to KR1020010074335A

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2003-06-02|Publication of KR20030043257A

优先权:

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申请号 | 申请日 | 专利标题

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KR1020010074335A|KR20030043257A|2001-11-27|2001-11-27|Light guide panel having lenticular lens and Back light apparatus using thereof|