KR100317882B1 - Plane light source unit and method for manufacturing hologram waveguide plate used for the same - Google Patents

Abstract

In a flat panel lighting apparatus used for a flat panel display such as an LCD, a holographic light guide plate configured to uniformly distribute the intensity of light emitted through the diffusion plate is provided. A hologram diffusion layer is formed on the bottom surface of the holographic light guide plate of the flat panel illuminating device, and the density of the unevenness forming the hologram of the hologram diffusion layer is higher in the side where the light source is located and lower in the distance from the light source. In addition, the hologram diffusion layer may be formed on the top surface of the hologram light guide plate, and the hologram diffusion layer on the top surface may be formed so that the density of irregularities forming the hologram is generally uniform so that the intensity of light emitted from the hologram light guide plate is uniformly distributed throughout.

Description

Flat lighting device and method for manufacturing hologram light guide plate used therein {Plane light source unit and method for manufacturing hologram waveguide plate used for the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel lighting apparatus used in a flat panel display such as a liquid crystal display (LCD) and a manufacturing method thereof. More specifically, the present invention relates to the improvement of a flat panel lighting device used as a back lighting means in a large LCD or similar display device.

Recently, instead of using a conventional thick CRT monitor, the development of a thin, light and flat panel display that emits no electromagnetic waves has been actively developed. Among them, LCD, a display device using liquid crystal, It is widely used as a representative flat panel display. The LCD requires a plane light source unit that emits light from the back of the LCD, and a representative configuration of such an illumination device is shown in FIG. 1. First, referring to FIG. 1, the configuration of a flat panel lighting apparatus will be described.

Referring to FIG. 1, a configuration of a flat panel lighting device used in a large LCD will include a light guide plate 2 disposed on at least one light source 1 having a long length, such as a linear lamp, and underneath the lamp 1. A reflector 3 is disposed to simultaneously perform scattering and reflection of light, and two or more diffuser plates 4 are sequentially stacked on the light guide plate, and then an LCD panel 5 is mounted thereon.

However, in order for an image to be displayed evenly and accurately on the LCD screen, it is required that the intensity distribution of light incident on the LCD panel 5 be uniformly distributed throughout the LCD panel. To this end, the conventional method has been to install a plurality of diffusion plate on the light guide plate.

The general operation principle (process of light ray) in the case of configuring the flat panel lighting device as described above will be described with reference to FIG.

Referring to FIG. 2, in the case of a flat panel lighting apparatus generally used in a large LCD panel, rays coming from the light source 1 are directly incident to the bottom surface of the light guide plate 2 (R2), The light is incident on the reflecting plate 3 below the light source (R1), scattered and reflected again by the reflecting plate, and then enters the light guide plate 2 again. Light rays incident on the light guide plate 2 pass through the top surface of the light guide plate, and the light intensity distribution on the top surface of the light guide plate is shown in FIG. 2 (c). Will have When the light intensity distribution is incident on the LCD panel while light rays are diffused sequentially through the diffusion plate, the light intensity distribution becomes uniform throughout as shown in FIG.

In such a prior art, it is necessary to use a plurality of diffusion plates in order to uniformly distribute the intensity of light incident on the LCD panel 5 throughout the LCD panel. In addition, since the intensity of light incident on the LCD panel is reduced by multiple diffusion plates, the number of lamps must be increased or a lamp having a high brightness must be used. In addition, there is a problem that the manufacturing cost increases by using a plurality of expensive diffusion plate.

It is an object of the present invention to provide an improved flat panel lighting device which solves the above-mentioned problems, and in particular, to provide a flat panel lighting device which can be manufactured with high performance and low manufacturing cost.

Another object of the present invention is to provide a method of manufacturing a hologram light guide plate that can be used in the improved flat panel lighting apparatus.

1 is a perspective view of a flat panel lighting apparatus that has been conventionally used for LCD.

2 is a view showing a light ray progression in the flat lighting device shown in FIG.

3A is a perspective view of a flat panel lighting apparatus according to a first embodiment of the present invention.

Fig. 3B is a diagram showing the relationship between the uneven density of the hologram diffusion layer and the lamp position in the flat lighting device according to the first embodiment of the present invention.

4A and 4B show a process of manufacturing a hologram according to the first embodiment of the present invention.

5 illustrates a hologram diffuser plate manufactured according to the methods of FIGS. 4A and 4B.

6 is a view showing a process of manufacturing a stamper from the hologram diffuser plate.

7 illustrates a method of manufacturing a hologram light guide plate using a stamper.

8 illustrates another method of fabricating a holographic light guide plate using a stamper.

9 illustrates another method of manufacturing a holographic light guide plate using a stamper.

10A is a perspective view of a flat panel lighting apparatus according to a second embodiment of the present invention.

Fig. 10B is a diagram showing the relationship between the concave-convex density and the lamp position of the first hologram diffusion layer in the flat lighting apparatus according to the second embodiment of the present invention.

FIG. 11 is a view showing a process of manufacturing a second hologram in a second embodiment of the present invention; FIG.

12 is a perspective view and a partially enlarged cross-sectional view showing a hologram plate produced according to the method shown in FIG.

FIG. 13 shows a method of manufacturing a hologram light guide plate using two stampers. FIG.

14 shows another method of fabricating a holographic light guide plate using two stampers.

15 is a view showing a light ray progression in the flat lighting device of Figure 3a implemented in accordance with the present invention.

16 is a view showing a light ray progression in the flat lighting device of Figure 4a implemented in accordance with the present invention.

In order to achieve the above object, a flat lighting apparatus provided by the present invention, one or more light sources; A reflection plate positioned below the light sources to simultaneously perform scattering and reflection of light; A hologram light guide plate positioned above the light source and having a holographic diffusion layer formed on one surface of the top and bottom surfaces thereof; And a diffuser plate positioned above the hologram light guide plate and diffusing light passing through the hologram light guide plate, wherein the hologram diffused layer has a higher density of irregularities forming the hologram and is located farther from the light source. It is a flat panel lighting device configured to have a low density, so that the intensity of light emitted through the diffusion plate is uniformly distributed throughout.

According to another aspect of the present invention, a flat panel lighting apparatus for a flat panel display includes: one or more light sources; A reflection plate positioned below the light sources to simultaneously perform scattering and reflection of light; And a light guide plate positioned above the light source and having a first hologram diffusion layer formed on a lower surface thereof and a second hologram diffusion layer formed on an upper surface thereof, wherein the first hologram diffusion layer has a density of irregularities forming the hologram. The higher the light source is located and the lower the light source, the lower the density. The second hologram diffusion layer has a uniform density of irregularities forming the hologram, so that the intensity of light emitted through the holographic light guide plate is generally increased. It is a flat panel lighting device configured to be uniformly distributed.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention.

<Example 1>

A first embodiment of the present invention will be described with reference to FIGS. 3A and 3B.

First, the embodiment of the present invention will be described. As shown in FIG. 3A, a hologram light guide plate 21 having a hologram diffuser layer 23 is positioned on an upper side of at least one long lamp 20 as a light source. Under the lamp 20, a reflector 22 that simultaneously performs scattering and reflection of light is positioned. The diffusion plate 24 is positioned above the hologram light guide plate 21, and the LCD panel 25 is mounted on the diffusion plate 24. The hologram diffusion layer 23 formed on the upper surface of the hologram light guide plate 21 is configured such that the density of the unevenness forming the hologram is higher at the side where the lamp is located and lower as the distance from the lamp increases.

The hologram diffusion layer 23 will now be described in more detail. As shown in FIG. 3B, the hologram diffusion layer 23 has the highest density of the unevenness forming the hologram H1 of the portion where the light source is located, and the unevenness of the unevenness forming the hologram H2 ... Hn as the distance from the light source 20 increases. The density is gradually lowered so that the density of irregularities is lowest in the middle between each light source. In addition, in this embodiment, although the hologram diffusion layer is formed on the upper surface of the holographic light guide plate, it is also possible to form the hologram diffusion layer on the lower surface of the light guide plate.

In this way, the density of the irregularities on the light source side is increased and the density of the irregularities on the light source side is decreased as the distance from the light source is increased, so that the light intensity on the light source side increases the intensity of light diffusion and lowers the intensity of light diffusion on the light source side. It is intended to be.

Hereinafter, a method of manufacturing the hologram diffusion layer will be described with reference to FIGS. 4A and 4B.

First, the laser beam emitted from the laser 100 is enlarged using the lenses 101 and 102, and the thus enlarged laser beam is incident on the diffuser plate 103 to diffuse. Then, the glass plate 106 coated with the photosensitive agent 105 is placed at a distance Li away from the diffusion plate, and the rest of the glass plate other than the width Hi (parts other than the width Hi) is moved to the blocking plate 104. Cover up. After exposing the laser beam diffused through the diffusion plate 103 to the width Hi for a predetermined time, the laser beam blocker 108 blocks the laser beam. After the laser beam is blocked, the distance Li between the diffuser plate 103 and the glass plate 106 is increased, and then the width Hi portion previously exposed to the laser beam is covered by the blocker 104 and the other portion not exposed to the laser beam. The laser beam blocker 108 is operated after exposing the region (symmetrically from the center of the glass plate) to the laser beam. If this process is repeated several times, the glass plate 106 is separated by Ln from the diffusion plate 103 and the exposed area of the photosensitive agent 105 applied to the glass plate 106 also starts from A and B, B '. The Hn region is exposed while facing away (see FIG. 4B). After repeating the above process until the exposed area reaches B, B 'and developing the glass plate 106 to which the photosensitive agent 105 is applied, the photosensitive agent is etched and thus, (a), (b) and (c) of FIG. Hologram plates 107, 107 ', and 107' made of holograms 105 'and 105' in which the density of the unevenness forming the hologram from A to B, B 'are gradually reduced. Hologram unevenness is denser than the unevenness 105 'at the center of the unevenness 105' at the outer side.

FIG. 5 shows a hologram plate manufactured by the method of FIG. 4, and (a) shows the hologram plate 107 when the exposure area Hi is constant (Hi = Hn) from A to B, B '. (B) shows the hologram plate 107 'when the exposure area Hi is gradually reduced (H> Hn) from A to B, B', and (c) is from A to B, B '. The hologram plate 107 ″ produced when the exposure area Hi is gradually increased (Hi <Hn) is shown.

Referring to Figure 6 will be described a stamper manufacturing process. When electroless plating is performed on the hologram plates 300 (107, 107 ′ and 107 ′ of FIG. 5), the metal film 304 is formed on the holograms 301 (105 ′ and 105 ′ of FIG. 5) ( S1-S2), when the metal film 304 is separated, the shapes of the holograms 105 'and 105' on the hologram plate 106 are duplicated as is, thereby producing a stamper 304 as a metal master (S3). ).

Hereinafter, with reference to FIGS. 7 to 9, three different methods of manufacturing the hologram light guide plate using the stamper 304 manufactured as described above will be described.

First, the UV curing method shown in FIG. 7 will be described. After the UV (Ultra Violet) curing agent 401 is applied onto the LGP 400 to fabricate the holographic LGP (S11), the UV curing time may not be completely hardened. Investigate only during (S12). Next, the stamper 304 manufactured by the method described above is attached to the UV curing agent coated on the light guide plate with the presser 403 attached to the light guide plate, and the pattern of the stamper is pressed and irradiated with UV in the pressed state (S13). Then, when the compactor 403 is separated from the light guide plate (S14), the holographic light guide plate on which the hologram layer of the form as shown in FIG. 5 is formed is completed.

The method shown in FIG. 8 as a second method of forming the holographic light guide plate, compared with the method according to FIG. 7, is applied only after applying the UV curing agent 501 (S21) for a time that the UV curing agent is not completely hardened. The steps are the same until step S22. However, the method shown in FIG. 8 is not irradiated with UV during pressing with the presser 503, but after pressing, the light guide plate is separated from the presser (S23) and then irradiated with UV (S24) to be applied onto the light guide plate. The UV curing agent is hardened to make a hologram layer (S25).

As another method of forming the hologram light guide plate, the method shown in FIG. 9 is provided with a stamper 304 fabricated in the manner described above on the mold structure 700 for injecting the light guide plate (S41) to place the light guide plate material 701 in the mold. It is produced by injection molding. After injecting the light guide plate material 701 into the mold (S42) and removing the mold after a predetermined time, a hologram light guide plate 703 having a hologram as shown in FIG. 5 is formed on the light guide plate (S43).

<Example 2>

Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 10A and 10B. First, as shown in FIG. 10A, a hologram light guide plate 31 is positioned on at least one long lamp 30, which is a light source, and a reflector 32 which simultaneously scatters and reflects light is positioned below the lamp. do. The hologram light guide plate 31 has a first hologram diffusion layer 33 on the bottom thereof and a second hologram diffusion layer 34 on the top thereof. The first hologram diffusion layer 33 formed on the bottom surface of the hologram light guide plate 31 has a higher density of the unevenness forming the hologram on the side where the lamp 30 is located and a lower density as the distance from the lamp increases. In the second hologram diffusion layer 34 formed on the upper surface of 31, the density of the irregularities forming the hologram is generally uniform.

The first hologram diffusion layer 33 formed on the bottom of the hologram light guide plate may be formed by a method similar to the hologram diffusion layer 23 described in the first embodiment.

Hereinafter, a method of manufacturing the second hologram diffusion layer 34 formed on the holographic light guide plate will be described with reference to FIGS. 11 and 12.

First, the laser beam emitted from the laser 200 is enlarged using the lenses 201 and 202, and the thus enlarged laser beam is incident on the diffuser plate 203 to diffuse. Then, the glass plate 205 coated with the photosensitive agent 204 is placed at a distance L from the diffusion plate 203, and the laser beam diffused from the diffusion plate 203 is exposed for a predetermined time, and then the photosensitive agent 204 is applied. ) Is developed, the photosensitive agent is etched to produce a hologram plate 207 as shown in FIG.

Then, using the hologram plate 207 manufactured as described above, a stamper which is a metal master is produced by the same method described in the first embodiment (Fig. 6).

Hereinafter, referring to FIGS. 13 and 14, two different methods of making a holographic light guide plate on which a first hologram diffusion layer 33 and a second hologram diffusion layer 34 are formed using a stamper manufactured as described above will be described. It demonstrates.

First, the UV curing method illustrated in FIG. 13 is applied to the upper and lower surfaces of the light guide plate 600 to be a holographic light guide plate (Ultra Violet curing agent 601,601 ') (S31) after the UV curing agent is completely hardened. Investigate only for a period of time (S32). Next, the stampers 603 and 604 are fabricated with the stampers 605 and 605 'attached to the light guide plate, and the pattern of the stamper is pressed and formed up and down on the UV curing agent applied on the light guide plate (S33). After separating from the UV irradiation by curing the UV curing agent completely (S34), the holographic light guide plate is formed on each of the top and bottom hologram layer is completed.

As another method of manufacturing the hologram light guide plate, the method shown in FIG. 14 is provided with stampers 802 and 803 fabricated in the manner described above up and down the mold structure 800 for injecting the light guide plate (S51). It is produced by injection molding. After injecting the light guide plate material 801 into the mold (S52) and removing the mold after a predetermined time, a hologram layer is formed on the top and bottom surfaces of the light guide plate (S53).

Hereinafter, with reference to FIG. 15 and FIG. 16, operation | movement of the flat panel lighting apparatus comprised as mentioned above according to this invention is demonstrated.

Referring to FIG. 15, in the case of the flat panel lighting apparatus according to the first embodiment, the rays coming from the light source 20 are incident through the bottom surface of the hologram light guide plate 21 (R2), or the light source. Is incident on the reflecting plate 22 below (R1). Light ray R1 incident on the reflecting plate is scattered and reflected again by the reflecting plate, and then enters the hologram light guide plate 21 again. The light beams incident on the hologram light guide plate pass through the hologram light guide plate 21 by the hologram diffusion layer 23 formed on the upper surface of the hologram light guide plate, which increases the light diffusion intensity at the light source side and decreases the light diffusion intensity as the light source moves away from the light source. The intensity distribution of has a light intensity distribution smoothed to some extent as shown in FIG. When the light rays having such a light intensity distribution are incident on the LCD panel 25 while being diffused through the diffuser plate 24, the light becomes uniformly as shown in FIG. 15B.

Referring to FIG. 16, the case of the flat panel lighting device used in the second embodiment will be described. The rays emitted from the light source 30 are transmitted through the first hologram diffusion layer formed on the bottom surface of the hologram light guide plate 31. It enters the hologram light guide plate (R2) or enters the reflector plate 32 below the light source (R1). The light beam R1 incident on the reflecting plate is scattered and reflected again by the reflecting plate 32 and is incident again to the hologram light guide plate 31. The light rays incident on the holographic light guide plate have a light intensity distribution inside the light guide plate by the hologram diffusion layer 33 formed on the bottom of the hologram light guide plate, which increases the light intensity toward the light source and decreases the light intensity as it moves away from the light source. As shown in (c) of 16, the light intensity distribution is somewhat smooth. When the light rays having such a distribution of intensity of light are incident on the LCD panel 35 while being diffused through the second hologram diffusion layer 34, the overall uniformity is obtained as shown in FIG.

Although the technical features of the present invention have been described with reference to specific embodiments, those skilled in the art to which the present invention pertains may make various changes and modifications within the scope of the technical idea according to the present invention. It is obvious.

When the holographic light guide plate is manufactured according to the above-described method, the manufacturing time of the flat panel lighting apparatus is not only short, but also easy to manufacture, and thus the manufacturing cost of the flat panel lighting apparatus including the holographic light guide plate can be reduced.

In addition, using a holographic light guide plate manufactured by the above method as shown in Figure 3a or 10a to configure a flat panel lighting device, using a flat panel lighting device using a holographic diffusion layer produced by the method of Figures 4a, 4b and 11 Since the light transmission efficiency is 90% or more, and the brightness of the LCD is increased compared to a device using multiple diffusion plates having a transmittance of about 60 to 70%, the number of lamps as light sources can be reduced, resulting in economical efficiency. And in terms of the light efficiency mentioned above.

Claims (11)

A flat panel lighting device used for flat panel display, One or more light sources; A reflection plate positioned below the light sources to simultaneously perform scattering and reflection of light; A hologram light guide plate positioned above the light source and having a hologram diffusion layer formed on one of an upper surface and a lower surface of the light source; And A diffusion plate positioned above the holographic light guide plate and diffusing light passing through the holographic light guide plate It is made, including The holographic diffusion layer is a flat panel lighting device such that the density of the unevenness forming the hologram is higher in the side where the light source is located and is lowered away from the light source. A flat panel lighting device used for flat panel display, One or more light sources; A reflection plate positioned below the light sources to simultaneously perform scattering and reflection of light; And A holographic light guide plate positioned above the light source and having a first hologram diffusion layer formed on a lower surface thereof and a second hologram diffusion layer formed on an upper surface thereof. It is made, including The first hologram diffusion layer has a higher density of unevenness forming the hologram and a lower density as the light source is located and moves away from the light source, and the second hologram diffusion layer has an overall density of unevenness forming the hologram. Flat panel lighting device to be uniform. In the flat panel lighting apparatus used in the flat panel display device, a method for manufacturing a holographic light guide plate having a holographic diffusion layer formed on one of the top or bottom surface, a) enlarging a laser beam emitted from the laser; b) injecting the enlarged laser beam into a diffuser plate; c) placing a substrate coated with a photosensitive agent at a distance from the diffusion plate, exposing only a portion of the substrate to the laser beam using a blocking plate, and then blocking the laser beam; d) increase the distance between the substrate and the diffuser plate, cover the area irradiated with the laser beam in the previous step with a blocking plate, and remove the unirradiated area immediately adjacent to the area irradiated with the laser beam in step c). Blocking the laser beam after exposure to it; e) repeating steps c) and d) until the laser beam is irradiated on the entire substrate to which the photosensitive agent is applied; And f) etching the photoresist by developing the substrate; Holographic light guide plate manufacturing method comprising a. The method of claim 3, g) electroless plating on the substrate to form a metal stamper in a form in which a photoresist is etched; h) after applying the UV curing agent to the light guide plate material, pressing the stamper to the UV curing agent irradiated with ultraviolet light to the extent that the UV curing agent is not completely cured; And i) irradiating ultraviolet light to completely cure the UV curing agent Hologram light guide plate manufacturing method further comprising. The method of claim 4, wherein The curing step of i) is a method of manufacturing a hologram light guide plate to completely cure the UV curing agent by irradiating ultraviolet rays in the state of irradiating ultraviolet rays in the step of pressing the stamper or removing the stamper. The method of claim 3, In performing the repetition of step e), the holographic light guide plate is manufactured so as to make the size of the exposed area constant each time, gradually reduce the first exposed area, or gradually increase the first exposed area. Way. The method of claim 3, g) electroless plating on the substrate to form a metal stamper in a form in which a photoresist is etched; And h) replicating the pattern of the stamper by installing the stamper on the upper surface of the mold structure and inserting the injection material; Hologram light guide plate manufacturing method further comprising. In the flat panel lighting apparatus used in the flat panel display device, a first hologram diffusion layer is formed on the bottom surface of which the density of irregularities forming the hologram is higher on the side where the light source is located and becomes lower as the light source moves away from the light source, and on the top surface there is a hologram. A method of manufacturing a hologram light guide plate in which a second hologram diffusion layer having an overall uniform density of irregularities for forming a film is formed, a) enlarging a laser beam emitted from the laser; b) injecting the enlarged laser beam into a diffuser plate; c) placing a first substrate coated with a photosensitive agent at a distance from the diffusion plate, exposing only a portion of the substrate to the laser beam using a blocking plate, and then blocking the laser beam; d) increase the distance between the first substrate and the diffuser plate, cover the area irradiated with the laser beam in the previous step with a blocking plate, and mark the unirradiated area immediately adjacent to the area irradiated with the laser beam in step c). Blocking the laser beam after exposure to the laser beam; e) repeating steps c) and d) until the laser beam is irradiated on the entire first substrate to which the photosensitive agent is applied; And f) etching the photosensitive agent by developing the first substrate; Forming a first hologram diffusion layer comprising a; And A) enlarging the laser beam emitted from the laser; B) injecting the enlarged laser beam into the diffuser plate; C) placing a second substrate coated with a photosensitive agent at a distance from the diffusion plate and exposing the laser beam diffused from the diffusion plate, and then blocking the laser beam; And D) etching the photosensitive agent by developing the second substrate; Forming a second holographic diffusion layer comprising a Holographic light guide plate manufacturing method comprising a. The method of claim 8, Electroless plating on the first substrate to form a first metal stamper in a form in which a photoresist is etched; Electroless plating on the second substrate to form a second metal stamper in a form in which a photoresist is etched; Applying a UV curing agent to the bottom and top of the light guide plate material and pressing the first metal stamper from below to the UV curing agent irradiated with ultraviolet light to the extent that the UV curing agent is not completely cured; And Irradiating UV light to completely cure the UV curing agent Hologram light guide plate manufacturing method further comprising. The method of claim 8, In the step of forming the first hologram diffusion layer, the size of the exposed area may be constant, reduced gradually from the first exposed area, or gradually increased from the first exposed area each time in the iterative step of e). Holographic light guide plate manufacturing method characterized by the above-mentioned. The method of claim 8, Electroless plating on the first substrate to form a first metal stamper in a form in which a photoresist is etched; Electroless plating on the second substrate to form a second metal stamper in a form in which a photoresist is etched; And Injecting the injection material by installing the first metal stamper and the second metal stamper on the lower surface and the upper surface of the mold structure, respectively Hologram light guide plate manufacturing method comprising a more.