KR20010008540A - Plane light source unit and method for manufacturing hologram layers used for the same - Google Patents

Abstract

PURPOSE: A plane illumination device is provided to have high performance and to be capable of being fabricated with low cost. CONSTITUTION: A plane illumination device comprises a long lamp(21) which is located at one side of a light guide plate(22) having the first hologram(28). A reflection plate(23) is located below the light guide plate(22), and the first diffusion plate(24), prism plates(25,26) and the second diffusion plate(26) are sequentially stacked on the light guide plate. The first hologram(28) has the same shape as a mask used to fabricate the hologram(28).

Description

Flat lighting device and method for forming hologram layer used therein {Plane light source unit and method for manufacturing hologram layers 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 an LCD (Liquid Crystal Display) 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 an 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. Such an LCD necessarily 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 FIGS. 1A and 1B, the configuration of a flat panel display will be described.

The configuration as shown in FIG. 1 (a) is mainly used for a large LCD (e.g., for a monitor and a wall-mounted TV), and the configuration as shown in FIG. 1 (b) is a relatively small and medium sized LCD (for example, a laptop computer). Is used for). In other words, referring to FIG. 1 (a), the structure of a flat panel lighting device used for a large LCD will be described. On both sides of the light guide plate 2, a long light source 1, 1 ', for example, a linear lamp will be described. ), A reflection plate (3) which simultaneously scatters and reflects light is placed on the bottom of the light guide plate, and two diffuser sheets (4, 5, diffuser sheet) are placed on top of the light guide plate, and then placed thereon. It is produced by mounting the LCD panel 6. In addition, referring to Fig. 1 (b), the configuration of a flat panel lighting device used in a small and medium-sized LCD is described. A long light source 11 (for example, a linear lamp) has one side (one side) of the light guide plate 12. And a reflecting plate 13 which simultaneously scatters and reflects light, and a prism edge as shown in (a) of FIG. A first prism sheet 15 formed in parallel with the X-axis, a second prism plate 16 having a prism edge parallel to the Z-axis, and a second diffuser plate as shown in FIG. 17) are placed on top of each other, and the LCD panel 18 is mounted thereon.

However, in order for an image to be displayed on the LCD screen evenly and accurately, it is required that the intensity distribution of light incident on the LCD panels 6 and 18 be uniformly distributed throughout the LCD panel. To this end, the conventionally adopted method is to perform additional processing such as irregularities on the light guide plate. This will be described in more detail below.

A configuration of a light guide plate of a type that has been conventionally used for the above-described purpose will be described in detail with reference to FIG. 3. As a typical form of the light guide plate treatment in which the intensity distribution of light incident on the LCD panels 6 and 18 is added to make it uniform throughout the LCD panel, the length of the lamp 11 is long as shown in FIG. The prism-shaped unevenness formed in parallel in the direction to the bottom of the light guide plate 12, or the method of forming a hemispherical unevenness of the dot pattern form to the bottom of the light guide plate 12 as shown in (b) of FIG. As shown in (c) of Figure 3 there is a method for printing the ink containing the scattering agent in the form of a dot pattern.

Referring to FIGS. 4 and 5, a general operation principle (processing of light rays) in the case of configuring a flat panel lighting apparatus as shown in FIG. 1 using such a light guide plate is as follows.

First, referring to FIG. 4, a case of a flat panel lighting apparatus generally used in a small and medium LCD panel will be described. When light rays emitted from the light source 11 are incident through one side (one side) of the light guide plate 12, the incident light rays travel inside the light guide plate while totally reflecting from the top or bottom surface of the light guide plate. These light rays are incident on the upper surface of the light guide plate at an angle at which the total reflection condition is broken while the total reflection is progressed in the light guide plate, or the convex or scattering ink formed on the bottom of the light guide plate as shown in (a), (b) and (c) of FIG. When the total reflection condition is broken by scattering from there, the light rays come out to the top surface of the light guide plate while maintaining its central axis at a constant angle (θ1) with the top surface of the light guide plate (indicated by "light ray 3" in FIG. 4). Meanwhile, the light rays incident on the bottom surface of the light guide plate at an angle at which the total reflection condition is broken are scattered and reflected again by the reflector 13 and are incident again to the light guide plate. The rays deviating from the light guide plate (the light ray 3) are incident on the first diffuser plate 14 and diffused again by the diffuser plate, thereby increasing the angle θ2 between the x-axis and the light rays (ray ray 4). These beams have a first prism plate (the corners of which are formed parallel to the X-axis and do not affect the light incident on the xy-plane, but the prism serves to narrow the diffusion angle to the light incident on the yz-plane. Incident on the γ 15 plane, the diffusion angle of the rays lying on the yz-plane is reduced. These rays (rays 5) are incident on the second prism plate 16 having the prism edges parallel to the Z-axis, so that the central axis of the rays ray-6 is caused by the second prism plate 16. parallel to the y-axis. In other words, the two beams of the prism plate narrow the diffusion angle and the light beams (ray-6) whose central axis is perpendicular to the upper surface of the light guide plate are scattered again by the second diffuser plate 17, so that a uniform light distribution is obtained. Incident on the LCD panel 18.

This time, the light propagation process in the flat panel lighting device for large LCD will be described with reference to FIG. As shown in FIG. 5A, when light rays emitted from two light sources 1 and 1 ′ on both sides of the light guide plate 2 are incident through both sides of the light guide plate 2, the incident light rays are incident. They totally reflect from the top or bottom of the light guide plate and proceed inside the light guide plate. These light rays are propagated while totally reflecting in the light guide plate, and are incident on the top surface of the light guide plate at an angle at which the total reflection condition is broken, or in uneven or scattering ink formed on the bottom of the light guide plate as shown in FIGS. 3A, 3B, and 3C. When the total reflection condition is broken by being hit and scattered from there, the light distribution of the light rays emitted from the upper surface of the light guide plate is in the form of two peaks as shown in FIG. When the light rays forming the light distribution pass through the first diffusion plate 4, the distribution becomes more uniform as shown in FIG. 5C, and when passing through the second diffusion plate 5, FIG. 5D. As a result, an overall uniform light distribution is obtained, and as a result, the intensity distribution of light incident on the LCD panel 6 is uniform.

As mentioned above, even with the above configuration, although it is possible to form a uniform distribution of light intensity incident on the LCD panels 6 and 18 throughout the LCD panel, it is used for this purpose. It is very difficult to produce a light guide plate (for example, a light guide plate as shown in Figs. 3A, 3B, and 3C). As a method adopted for manufacturing such a conventional light guide plate, for example, in the case of adding a concave-convex to the light guide plate ((a) and (b) of FIG. 3), a method of processing with a diamond blade to form the concave-convex or concave-convex A method of manufacturing and injecting a mold having a fine pattern of a shape is used. However, the diamond blade processing method is difficult to remove the fluff generated when forming a fine pattern of diamond and takes a long time to form the pattern. In addition, as the injection method by a mold, it is not only easy to manufacture a mold having a fine pattern, which is small in size of several tens of micrometers and not uniform in size, and the manufacturing cost is very high. Therefore, the manufacturing method of the light guide plate by the mold material is a factor that increases the price of the light guide plate, and the manufacturing conditions are difficult, resulting in an increase in the defective rate of the product.

On the other hand, the method of printing the dot pattern instead of forming the irregularities as shown in (c) of Figure 3, because the printing process takes a long time, not only lowers the production efficiency, but also high defect rate, resulting in a decrease in productivity, This in turn raises the price of the light guide plate. In addition, the scattering agent added to the ink and the ink serves to absorb the light has the disadvantage that the light intensity is reduced. In addition, all the conventional methods described above require multiple diffusion plates and prism plates to be used as shown in FIGS. 1, 2, and 3 to ensure uniformity of light and viewing angle of the LCD, which complicates the assembly process. There is also a problem that increases the manufacturing cost of the product.

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 for manufacturing a first hologram layer and a second hologram layer of a light guide plate which 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, (a) is for a large LCD, (b) is a view showing a flat lighting apparatus for small and medium-sized LCD.

2 is a view showing in detail the configuration of the prism plate used in FIG.

3 is a view showing in detail the configuration of a conventional light guide plate.

4 is a view showing a light ray progression in the flat lighting device shown in Figure 1 (b).

FIG. 5 (a) is a view showing the light propagation process in the flat lighting apparatus shown in FIG. 1 (a), FIG. 5 (b) shows the distribution of light on the upper surface of the light guide plate, and FIG. Fig. 5D is a diagram showing the distribution of light after passing through the first diffusion plate, and Fig. 5D shows the distribution of light after passing through the second diffusion plate.

Figure 6 is a view showing an embodiment according to the present invention, (a) is a small and small LCD, and (b) is a diagram showing the implementation for each large LCD.

7 is a view showing another embodiment according to the present invention, (a) is shown for the small and medium LCD, (b) is implemented for a large LCD, respectively.

8 (a) (b) (c) (d) show patterns of four types of masks that can be used in FIGS. 6 (a) and 7 (a).

9 (a) (b) (c) (d) show a pattern of four types of masks that can be used in FIGS. 6 (b) and 7 (b).

(A) and (b) of FIG. 10 are views showing patterns of two types of masks that can be used in FIGS. 6 (a) and 7 (a).

11A and 11B show patterns of two types of masks that can be used in FIGS. 6B and 7B.

12 is a view showing a process of manufacturing a negative hologram using a mask.

Figure 13 is a perspective view and a partially enlarged cross-sectional view showing a hologram plate produced in accordance with the process shown in FIG.

14 is a view showing a process of manufacturing an embossed stamper from the intaglio hologram.

15 is a perspective view and a partially enlarged view showing a stamper manufactured according to the process shown in FIG.

16 is a view showing a process of manufacturing an embossed hologram using a mask.

17 is a perspective view and a partially enlarged cross-sectional view showing the embossed hologram plate produced in accordance with the process shown in FIG.

18 is a view showing a process of manufacturing an intaglio stamper from an embossed hologram;

19 is a perspective view and a partially enlarged view showing a stamper of an intaglio produced by the process of FIG.

20 is a view showing a method of generating a hologram on a light guide plate using the stamper.

FIG. 21 illustrates another method of generating a hologram on a light guide plate using the stamper. FIG.

Fig. 22 (a) shows a replica hologram using an embossed stamper, and (b) shows a replica hologram using an embossed stamper.

FIG. 23 shows a method of making a second hologram layer in which the density of irregularities is gradually changed; FIG.

24 is a perspective view and a partially enlarged cross-sectional view showing a second hologram layer produced according to the method shown in FIG. 23.

25 shows another method of making a second hologram layer in which the density of the unevenness is gradually changed.

26 is a perspective view and a partially enlarged cross-sectional view showing a second hologram layer produced according to the method of FIG. 25.

FIG. 27 is a view showing a hologram plate in which the hologram plates of FIGS. 24 and 26 are coupled with a center line C as a symmetry line;

28 is a view showing a light ray progression in the flat lighting device of Figure 6 (a) implemented in accordance with the present invention.

FIG. 29 is a view showing a ray propagation process in the flat lighting apparatus of FIG. 7 (a) implemented according to the present invention; FIG.

In order to achieve the above object, a flat lighting apparatus provided by the present invention, a transparent light guide plate; A light source positioned at one side of the light guide plate; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first diffusion plate positioned above the light guide plate and configured to first diffuse light emitted through an upper surface of the light guide plate; A first prism plate formed of a plurality of prisms configured to be perpendicular to a length direction of the lamp and a prism edge thereof, and changing a traveling direction of incident light; A second prism plate formed of a plurality of prisms configured to have the longitudinal direction of the lamp and the prism edges parallel to each other, and changing a traveling direction of the incident light; And a second diffuser plate for secondarily diffusing light passing through the second prism plate, and on the bottom surface of the light guide plate, the density of the pattern made of holograms is lower from the side where the lamp is located. It is a flat panel lighting device configured to form a first hologram layer having a higher density as it is farther away, so that the intensity of light emitted through the secondary diffusion plate is uniformly distributed throughout.

According to still another aspect of the present invention, a flat panel lighting apparatus for a flat panel display includes: a transparent light guide plate; Light sources positioned at both sides of the light guide plate; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first diffusion plate positioned above the light guide plate and configured to first diffuse light emitted through an upper surface of the light guide plate; And a second diffuser plate for secondly diffusing the light scattered by the first diffuser plate, wherein the bottom surface of the light guide plate has a low density of patterns made of holograms on the lower side where the two lamps are located. As the distance from the lamp increases, the density is increased so that the center between the two lamps forms a first hologram layer having the highest density of patterns, so that the intensity of light emitted through the second diffusion plate is distributed evenly throughout. It is a flat panel lighting device.

According to another aspect of the present invention, a flat panel lighting apparatus for a flat panel display device includes: a transparent light guide plate; A lamp located on one side of the light guide plate as a light source; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first prism plate made of a plurality of prisms configured to be perpendicular to a longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; A second prism plate made of a plurality of prisms configured to be parallel to the longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; And a diffuser plate for diffusing the light passing through the second prism plate, wherein a lower surface of the light guide plate has a pattern of holograms having a lower density at a side where the lamp is located and being farther from the lamp. Forming a first hologram layer having a higher height, and forming a second hologram layer having a higher density of the unevenness forming the hologram on the upper surface of the light guide plate, the lower the side where the lamp is located and the higher the distance from the lamp. It is a flat panel lighting apparatus which distributes light intensity uniformly distributed through the diffusion plate on the second prism plate.

According to still another aspect of the present invention, there is provided a flat panel lighting apparatus including: a transparent light guide plate; a light source positioned at both sides of the light guide plate; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; Located above the light guide plate, the light guide plate is composed of a diffuser plate for diffusing light emitted from the upper surface of the light guide plate, the lower surface of the light guide plate has a low density of the pattern consisting of holograms to the two lamps are located The first hologram layer having a higher density is formed as it moves away from the second light guide plate, and the second hologram whose density of irregularities forming the hologram on the upper surface of the light guide plate is lower at the side where the two lamps are located and farther from the two lamps. A flat panel lighting apparatus is provided so that a layer is formed so that the intensity of light emitted through the diffusion plate is uniformly distributed throughout.

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. 6A and 6B.

First, the embodiment of the present invention in relation to the small and medium-sized LCD will be described. As shown in FIG. 6A, a light source is disposed at one side of the light guide plate 22 having the first hologram layer 28 at the bottom thereof. The long lamp 21 is positioned, and under the light guide plate 22 is a reflection plate 23 which simultaneously performs scattering and reflection of light, and a first diffuser plate 24 and (a) of FIG. 2 above the light guide plate. As shown in FIG. 2B, the prism plate 25 having the prism edges parallel to the X-axis, and the prism plate 26 and the second diffusion plate 27 having the prism edges parallel to the Z-axis as shown in FIG. The first hologram layer 28 formed to be stacked and formed under the light guide plate 22 may be, for example, FIGS. 8A, 8B, 8C, 10D, or 10A. It is manufactured from the mask of any one of (b), and has the same form as the mask. In the above form each pattern is a hologram.

Now, the above mask patterns will be described in more detail. (A) of FIG. 8 arranges a circular (or polygonal) pattern such that the distance between the patterns in the x-direction (more precisely, the distance between the centers of the patterns) Gx and the distance Gz between the patterns in the z-direction are constant. The size of the pattern on the side (A) is small and gradually increases as the distance from the light source increases, and (b) of FIG. 8 is in every other line in the form of (a). ) It is moved by half (Gh = Gz / 2) of the distance between the patterns in the z-direction. (C) of FIG. 8 is a form in which the size of the pattern is constant and the distance in the x-direction of the pattern of the side A where the light source is located is widened and the distance is narrowed away from the light source (that is, Gx1> Gx2). , the z-direction spacing is equal to the spacing Gz1 on the side where the light source is located equal to the spacing Gzi on the pattern away from the light source, or as Gzi narrows away from the light source (ie Gz1> = Gzi). It is even higher form, except that Gz1 = Gz2 is shown in FIG. FIG. 8 (d) shows patterns in which the patterns are moved by half (Gh ′ = Gzi / 2) of the distance between the patterns in the z-direction in the form of (c).

10A illustrates a case where the shape of the hologram is a stripe (stripes), and the spacing of stripes in the X-direction (more precisely, the distance between the longitudinal center lines of each stripe strip) Although constant (Gz1 = Gz2), the size (width) of the stripe is enlarged as it moves away from the light source (W1 <W2). On the other hand, in the case of Figure 10 (b) the size of the stripes are the same (W3 = W4), the distance between the stripes is narrower as the light source is far higher the density of the stripes.

The smaller the pattern density at the light source side and the larger the pattern density at the light source side, the more uniform the light distribution is by reducing the light scattering on the light source side and increasing the light scattering away from the light source. .

Next, the first embodiment of the present invention will be described with respect to the implementation for a large LCD.

As shown in FIG. 6B, long lamps 31 and 31 ′, which are light sources, are disposed on both sides of the light guide plate 32 having the first hologram layer 36 at the bottom thereof, and the light guide plate 32 is disposed. The bottom of the light guide plate is a reflection plate 33 which simultaneously performs scattering and reflection of light, and two first and second diffusion plates 34 and 35 are sequentially stacked on the light guide plate, and are formed below the light guide plate 32. The first hologram layer 36 is made of a mask of any one of FIGS. 9 (a), (b), (c), (d), and 11 (a) and (b) of FIG. It has the same pattern pattern. Also in the above form each pattern is a hologram.

On the other hand, in the implementation of the pattern, when the shape of the hologram is circular or polygonal, unlike (a), (b), (c), (d) of FIG. It is preferable to make the pattern density of the center portion the highest by forming each pattern symmetrically at the center line C as shown in (a), (b), (c) and (d).

When the pattern of the hologram is striped, for example, as shown in (a) and (b) of FIG. 11, unlike in (a) and (b) of FIG. It is preferable to make it symmetrically formed so that the pattern density of a center part may be the highest.

As mentioned above, the pattern density at the light source side is smaller and the pattern density at the light source side is larger, so that the light source side reduces light scattering and increases light scattering away from the light source. 9 and 11, the reason for the high pattern density at the center is that in the case of a large LCD, as shown in FIGS. 6 (b) and 7 (b), light sources are disposed on both sides of the light guide plate. Because they are located at each.

Hereinafter, a method of manufacturing a hologram having the above form will be described with reference to FIG. 12.

First, the laser beam emitted from the laser 100 is enlarged using the lenses 101 and 102, and the enlarged laser beam is incident and diffused by a diffuser glass 103. Then, the glass plate 105 coated with the photosensitive agent 106 is placed at a distance L from the diffuser 103, and the patterned portion is transparent and the other portion is opaque so that the photosensitive agent is applied to the surface side. One mask [preferably (a), (b), (c), (d) of FIG. 8 for small and medium-sized LCDs, (a), (b) of FIG. 10, and (9) for large LCDs a), (b), (c), (d), the mask of any one of the forms of (a), (b) of FIG. 11] 104, and the diffuser 103 through the transparent portion of the mask. The photosensitizer is exposed to the laser beam scattered from it. In the device configuration as described above, the laser beam diffused from the diffuser 103 through the transparent portion of the mask 104 to the photosensitive agent, and after a predetermined time passes through the development process, as shown in FIG. ), (b), (c), (d), (a), (b), (c), (d), (a), (b) and (a) of FIG. In the form of (b), the photoresist of the portion irradiated to the laser beam is etched in the speckle shape of the laser beam to form the hologram 108. That is, the hologram plate 109 in which the holograms 108 are arranged in accordance with the pattern of the mask used is manufactured.

Then, electroless plating the hologram plate 109 thus manufactured as shown in FIG. 14 is not exposed to the laser beam by the holograms 108 and the mask 104 as shown in FIG. When the metal film 110 is formed on the remaining photoresist 106, and the metal film 110 is separated as shown in FIG. 14C, the shapes of the holograms 108 on the glass plate 105 are embossed. As it is copied in the form of a metal master stamper 110 is produced.

Hereinafter, with reference to FIGS. 20 and 21, two different methods of making a hologram layer under the light guide plate using the stamper 110 manufactured as described above will be described.

First, the first method shown in FIG. 20 will be described. After the UV (Ultra Violet) curing agent 401 is applied onto the light guide plate 400 (step-1), UV is applied only for a time such that the UV curing agent is not completely hardened. Investigate (step-2). Next, the stamper 405 is manufactured by the above-described stamper 403, and the stamper 405 is pressed and formed on the UV curing agent applied on the light guide plate, and the UV is irradiated in the compressed state (step-3). Then, when the presser is separated from the light guide plate (step-4), the light guide plate is shown in FIGS. 8 (a), (b), (c), (d), and (a), (b) and (c) of FIG. ), (d), the first hologram layer in which the holograms 406 are arranged in the form of (a) and (b) of FIG. 10 and (a) and (b) of FIG. It is formed as

The method shown in FIG. 21 as a second method of hologram formation is the same as in step-2 compared to the method according to FIG. 20, but the method according to FIG. The method according to 21 does not irradiate UV during pressing with the press, but after pressing the light guide plate is separated from the press once and then irradiated with UV (step-4) to harden the UV curing agent applied on the light guide plate to harden the first hologram layer. It is different in that it makes

Also, as described above, a method of manufacturing a first hologram layer by manufacturing a stamper having an intaglio, instead of making the stamper into an emboss, is illustrated in FIG. 16.

That is, the laser beam emitted from the laser 200 is enlarged using the lenses 201 and 202, and the enlarged laser beam is incident on the diffuser plate 203 to diffuse. Then, the glass plate 205 coated with the photosensitive agent 204 is directed to the diffuser plate 203 toward the diffuser plate 203 at a distance L from the diffuser plate by exposure to the laser beam scattered from the diffuser plate 203. Let's do it. With the above device configuration, the photosensitive agent 204 is exposed to the speckle shape of the laser beam when the laser beam is exposed to the laser beam for a predetermined time, and the glass plate 205 to which the photosensitive agent 204 is primarily applied to the laser beam is thus applied. On the contrary, as shown in FIG. 16 (b), in contrast to the front, the patterned portions are opaque and the other portions are transparent so that light can pass through (a), (b), (c), any one of (d), (a), (b), (c) and (d) of FIG. 9, (a) and (b) of FIG. 10, and (a) and (b) of FIG. A mask 207 having a pattern of &lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt; is attached, and UV is irradiated with the UV lamp 206 through the transparent portion of the mask. When the development after the UV irradiation, as shown in Figure 17, the UV-irradiated portion is completely etched, the portion irradiated by the laser beam first and the UV irradiation blocked by the mask 207 is partially etched in the shape of speckle Embossed holograms 208 are made. That is, the hologram plate 209 in which the holograms 208 are arranged according to the pattern of the used mask is manufactured. When electroless plating is performed on the manufactured hologram plate 209 as shown in FIG. 18, the hologram 208 and the photosensitive agent 204 are completely etched and exposed as shown in FIG. 210 is formed. Then, when the metal film 210 is separated as shown in FIG. 18C, the holograms 208 on the glass plate 205 are replicated in the form of intaglio, thereby producing a stamper 210 which is an intaglio metal master. do. In the case of the intaglio stamper, the first hologram layer shown in FIG. 22B may be formed on the light guide plate using the same method as that of the embossed stamper (see FIGS. 20 and 21).

<Example 2>

Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 7A and 7B. Similarly to the case of the first embodiment described above, Fig. 7 (a) shows a small and medium-sized LCD, and Fig. 7 (b) shows an implementation in a flat panel lighting device used for a large LCD.

First, referring to FIG. 7A, the embodiment of the second embodiment according to the present invention will be described in the form of a flat panel lighting device used for a small and medium-sized LCD. The first hologram layer 47 is formed on the bottom surface of the light guide plate, and the second hologram layer 48 is formed on the top surface of the light guide plate. In addition, the light guide plate 42 has a reflector plate 43 that simultaneously performs scattering and reflection of light, and a first prism having a prism edge parallel to the X-axis as shown in FIG. A plate 44, a second prism plate 45 having a prism edge parallel to the Z-axis as shown in FIG. 2B, and a diffusion plate 46 are sequentially stacked.

On the other hand, in the form of implementing the second embodiment of the present application on a large LCD as shown in (b) of FIG. 7, long lamps 51 and 51 ′, which are light sources, are located on both sides of the light guide plate 52. The first hologram layer 55 is formed on the bottom surface of the light guide plate, and the second hologram layer 56 is formed on the top surface of the light guide plate, and the reflector plate 53 simultaneously performs scattering and reflection of light under the light guide plate 52. There is a diffusion plate 54 above the light guide plate.

In both cases, the first hologram layers 47 and 55 formed under the light guide plate are formed in the same manner as described with reference to FIGS. 6A and 6B in the first embodiment.

Meanwhile, the manufacturing process of the second hologram layers 48 and 56 formed on the upper surface of the light guide plate is as follows. First, a hologram is manufactured using two methods as shown in FIGS. 23 and 25, and a stamper is manufactured in the same manner as described above in connection with the configuration of FIGS. 6A and 6B from the hologram thus produced. After that, the second hologram layer may be formed on the light guide plate in the same manner as in FIGS. 20 and 21.

More specifically, the hologram manufacturing method of FIG. 23 will be described. The laser beams emitted from the laser 300 are enlarged using the lenses 301 and 302, and the enlarged laser beams are incident to the diffuser 303 to diffuse. And the glass plate 305 to which the photosensitive agent 304 was apply | coated was provided so that the angle of (theta) s may be made to the optical axis of a laser beam at the distance L by a fixed distance L. Then, one corner A portion of the glass plate 305 is separated from the diffuser plate by L1 (= L-Lcosθs / 2), and the opposite edge B is separated by L2 (= L + Lcosθs / 2), and the laser diffused from the diffuser plate 303 The beam is irradiated to the glass plate inclined. The size of the speckle pattern of the laser beam diffused from the diffuser plate 303 increases as the distance increases. In other words, the small speckle pattern is distributed at a position close to the diffuser plate 303, resulting in high density of irregularities. The further away from the diffuser plate, the larger the speckle pattern is, resulting in a lower density of irregularities. Therefore, when the optical system is configured as shown in FIG. 23, the size of the speckle pattern gradually increases from A to the distance B to the distance from the diffuser plate, and to the glass plate 305 coated with the photosensitive agent. When irradiated after irradiating the laser beam, a hologram plate 306 or a second hologram layer made of holograms 304 ′ and 304 ″ in which the unevenness density gradually decreases from A to B as shown in FIG. 24 is manufactured.

Next, with reference to FIG. 25, the further manufacturing method of the hologram plate by which the density of unevenness | corrugation gradually decreases is demonstrated. First, the laser beams emitted from the laser 500 are enlarged using the lenses 501 and 502, and the thus enlarged laser beams are incident on the diffuser 503 to diffuse. Then, the glass plate 506 to which the photosensitive agent 505 is applied is placed at a distance Li away from the diffusion plate, and the other portion of the glass plate 506 to which the photosensitive agent 505 is applied (with only a portion of Hi left) A part other than Hi) is covered by the blocking plate 504. After exposing the laser beam diffused from the diffusion plate to the Hi portion for a predetermined time, the laser beam blocker 508 blocks the laser beam. After the laser beam is blocked, the distance Li between the diffuser plate and the glass plate 506 is increased, and then the Hi portion previously exposed to the laser beam is covered by the blocking plate 504, and the other part of the laser beam is not exposed to the laser beam. The laser beam blocker 508 is activated after exposure. If this process is repeated several times, the glass plate 506 is separated by Ln from the diffuser plate 503 and the exposure area of the photosensitive agent 505 applied to the glass plate 506 also starts from A to the B side. The Hn region is exposed (see FIG. 25B). When the glass plate 506 coated with the photosensitive agent 505 is developed after repeating the above process until reaching the point B, the photosensitive agent is etched, and A to B as shown in FIGS. 26A, 26B, and 26C are illustrated. Hologram plates 507, 507 ', and 507' made of holograms 505 'and 505 &quot;, in which the density of the unevenness is gradually lowered, are produced.

FIG. 26 illustrates a second hologram layer manufactured by the method of FIG. 25, wherein (a) shows a case where the exposed area Hi from A to B is constant (Hi = Hn), and FIG. In the case where the exposure area Hi is gradually increased (H <Hn) from A to B, and FIG. 26 (c) is produced when the exposure area Hi is gradually decreased (Hi> Hn) from A to B. The second hologram layers 507, 507 ', 507 "are shown, respectively.

The second hologram layer manufactured by the above-described method may be applied to the present embodiment implemented in the small and medium-sized LCD, that is, the configuration as disclosed in FIG. 7A, and the present embodiment is implemented in the large LCD. That is, in the configuration as disclosed in (b) of FIG. 7, the density of the unevenness in which the second hologram layer manufactured as described above is symmetrically coupled to the center line C as shown in FIG. 27 to form the hologram is obtained. A composite hologram diffuser is used, which is the highest and lowers in both directions away from the centerline.

Hereinafter, with reference to FIG. 28 and FIG. 29, the operation of the flat panel lighting device configured as described above according to the present invention will be described.

First, in the first embodiment, in the configuration as shown in Fig. 6A, light emitted from the lamp 21 serving as the light source is totally reflected inside the light guide plate 22 (dotted line in Fig. 28) inside the light guide plate 22. When the light hits the area A with the hologram, the light is scattered and proceeds toward the reflecting plate 23, and the light rays directed to the reflecting plate are scattered back into the various light beams by the reflecting plate and reflected at the same time (B). . When the light entering the light guide plate passes through the region without the hologram, the light enters the light guide plate as it is, but when the light passes through the hologram area C, the light is scattered by the holograms and propagated toward the top of the light guide plate. When the light rays collide with the upper surface of the light guide plate, part of the light beam is transmitted and part is reflected. Some of the rays reflected in the part D and whose total reflection condition is broken are those which exit the light guide plate when they are directed to the area without the hologram, hit the reflector again, are scattered again at the point E and are reflected at the same time, and pass through the area where the hologram is located. Scatters again and faces the reflector. By repeating the above-described process numerous times, the distribution of light rays emitted from the upper surface of the light guide plate becomes uniform throughout the light guide plate. Subsequent progression of the light rays exiting the top of the light guide plate is the same as described for the conventional device.

On the other hand, in the case of Fig. 6B, the principle of operation of the light guide plate is the same as that described above except that lamps are used on both sides of the light guide plate in order to sufficiently secure the light amount for the large LCD.

In addition, in the second embodiment, the planar lighting device using the light guide plate 42 having the first hologram layer 47 on the bottom and the second hologram layer 48 on the top, as shown in FIG. The role of the first hologram layer formed on the bottom of the light guide plate is the same as described in the configuration of FIG. 6A (see FIG. 28), and the second hologram layer is formed of the diffusion plate adjacent to the top of the conventional light guide plate (14 of FIG. 1B). Play a role very similar to). However, when the second hologram layer is directly formed on the light guide plate as described above, the light transmittance of the second hologram layer is 90% or more, and the light efficiency is remarkably higher than that of the conventional diffuser plate having a light transmittance of only 50 to 60%. The same goes for the first hologram layer formed on the bottom of the light guide plate. In addition, the size of the irregularities forming the hologram is less than 10㎛, it is possible to achieve a uniform light distribution than the general diffuser plate made of particles of 50 ~ 100㎛.

In the case of Fig. 7B, the principle of operation of the light guide plate is the same as that described above except that lamps are used on both sides of the light guide plate in order to sufficiently secure the amount of light for the large LCD.

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 light guide plate is manufactured according to the method described above, the manufacturing time of the light guide plate is not only short, but also easy to manufacture, thereby reducing the manufacturing cost of the flat panel lighting apparatus including the light guide plate.

In addition, as shown in FIG. 6 or 7 by using the light guide plate manufactured in such a manner, a planar lighting device is constructed, and FIGS. 8 (a), (b), (c), (d), and FIG. First hologram layer made of any one of (a), (b), (c), (d), (a) and (b) of FIG. 10 and (a) and (b) of FIG. In the case of a flat panel lighting device using the second hologram layer, the light transmission efficiency is 90% or more, and the brightness of the LCD is increased compared to a device using a conventional diffusion plate having a transmittance of about 40 to 60%. This also has the advantage of reducing power consumption. Thus, for example, a notebook computer employing such a flat panel lighting device can be used longer than the conventional one.

Furthermore, the planar lighting apparatus using the light guide plate of the form which has a 2nd hologram layer on the upper surface of a light guide plate does not need the separate diffuser plate with low light transmittance (50-60%) used conventionally, and it is economical and the said It is also excellent in light efficiency mentioned in the above.

Claims (15)

A flat panel lighting device used for flat panel display, Transparent light guide plate; A light source positioned at one side of the light guide plate; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first diffusion plate positioned above the light guide plate and configured to first diffuse light emitted through an upper surface of the light guide plate; A first prism plate made of a plurality of prisms configured to be perpendicular to a longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; A second prism plate made of a plurality of prisms configured to be parallel to the longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; And And a second diffuser plate for secondarily diffusing light passing through the second prism plate, On the bottom surface of the light guide plate, a first hologram layer is formed such that the density of the pattern made of the holograms is lower at the side where the light source is located and increases as the distance from the light source is increased, thereby exiting through the secondary diffuser plate. A flat panel lighting device that distributes light uniformly throughout. A flat panel lighting device used for flat panel display, Transparent light guide plate; A light source positioned at one side of the light guide plate as a light source; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first prism plate made of a plurality of prisms configured to be perpendicular to a longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; A second prism plate made of a plurality of prisms configured to be parallel to the longitudinal direction of the light source and a prism edge, and changing a traveling direction of incident light; And It comprises a diffusion plate for diffusing the light passing through the second prism plate, On the bottom surface of the light guide plate, a first hologram layer having a density of patterns made of holograms is formed at a lower side where the light source is located and farther from the light source, and has a higher density, and a hologram is formed on the top surface of the light guide plate. The second hologram layer is formed such that the density of the unevenness is lower and the higher the distance from the light source is located, the higher the intensity of light emitted through the diffuser plate on the second prism plate is. Flat panel lighting equipment. The method according to claim 1 or 2, The first hologram layer is composed of a plurality of holograms having a circular or polygonal shape, and the size of the plurality of holograms is gradually increased as the distance from the light source starts from the side where the light source is located. The arrangement of the plurality of holograms is arranged in such a way that the spacing between the centers of the holograms is kept constant in the horizontal and vertical directions, or in such a state, the holograms are crossed line by line along the longitudinal direction of the light source. Flat panel lighting device characterized in that arranged by moving in the longitudinal direction of the light source by half of the interval. The method according to claim 1 or 2, The first hologram layer is formed of a plurality of holograms having a circular or polygonal shape and of constant size, and the arrangement of the holograms is such that the distance between the centers of the holograms starts from the side of the lamp and moves away from the lamp. The flat plate is characterized in that arranged in a progressively decreasing manner, or arranged in such a state that the holograms are moved in the longitudinal direction of the lamp by half the distance between the centers of the holograms by one line along the longitudinal direction of the lamp. Lighting device. The method according to claim 1 or 2, The first hologram layer is composed of a plurality of holograms having a stripe shape, each hologram is maintained at a constant distance in the longitudinal direction of the light source, the width of each of the stripe hologram starting from the light source side from the light source The flat illumination device, characterized in that configured to gradually increase as the distance, or the width of the stripe is constant, but the distance between the hologram gradually narrower as the distance from the light source from the side of the light source is gradually narrowed. A flat panel lighting device used for flat panel display, Transparent light guide plate; Light sources positioned at both sides of the light guide plate as a light source; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; A first diffusion plate positioned above the light guide plate and configured to first diffuse light emitted through an upper surface of the light guide plate; And And a second diffuser plate for secondarily diffusing light diffused by the first diffuser plate, On the bottom surface of the light guide plate, the first hologram layer having the highest density of the pattern having the highest density of the pattern of holograms having the lowest density at the side where the two light sources are located and moving away from the two light sources is higher. Flat panel lighting device to form a, uniformly distributed throughout the intensity of the light emitted through the secondary diffusion plate. A flat panel lighting device used for flat panel display, Transparent light guide plate; Light sources positioned at both sides of the light guide plate; A reflection plate positioned below the light guide plate to simultaneously perform scattering and reflection of light; And It comprises a diffusion plate for diffusing the light passing through the light guide plate, On the bottom of the light guide plate, a first hologram layer having a density of patterns made of holograms has a lower density at the side where the two light sources are located and increases away from the two light sources, and a hologram is formed on the top of the light guide plate. The second hologram layer is formed at a lower density at the side where the two light sources are located, and the further away from the two light sources, the second hologram layer is formed so that the intensity of light emitted through the diffuser plate on the prism plate is uniform. Flat panel lighting device. The method according to claim 6 or 7, In the first hologram layer, holograms having a circular or polygonal shape are arranged with the center-to-center spacing at a constant distance in the horizontal and vertical directions, or in this state, the lines of the holograms in the light source length direction are crossed line by line. Arrange and move by half the pattern spacing in the longitudinal direction of the light source. Flat panel lighting apparatus characterized in that the size of the holograms on the side with the two light sources is gradually increased as the distance from the two light sources to increase the density of the central portion between the two light sources. The method according to claim 6 or 7, The first hologram layer comprises holograms having a circular or polygonal shape and having a constant size, and each hologram has two intervals between the centers of the holograms in the light source length direction starting from the side where the two light sources are located. The two light sources are arranged to be gradually reduced away from the light source (i.e. toward the center), or arranged in such a state as to move the light source longitudinal direction of the hologram by one half of the pattern spacing in a line lengthwise direction. Flat panel lighting device characterized in that the density of the central portion between the highest. The method according to claim 6 or 7, The first hologram layer includes a plurality of stripe-shaped holograms, which are equally spaced in the longitudinal direction of the light source, but gradually as the width of the stripe hologram on the side where the two light sources are located increases from the two light sources. Or the stripe width is constant, but the distance between the holograms is gradually narrowed as the distance between the two light sources is greater from the light source side, so that the density of the hologram is configured to be the highest in the center between the two light sources. Flat lighting device. A method of forming a second hologram layer on a light guide plate used in the lighting apparatus of claim 2 or 7, Enlarging the laser beam emitted from the laser and entering the diffuser; By exposing the glass plate coated with the photosensitive agent to the laser beam diffused from the diffuser in a state inclined at an angle to the optical axis of the laser beam, a portion close to the diffuser plate becomes a small speckle pattern and the diffuser plate Sensitizing the photosensitizer applied on the glass plate such that the distant portions become a speckle pattern that gradually increases with distance from each other; Developing the glass plate to etch a photosensitive agent; Electroless plating on the glass plate to form a metal stamper in a form in which a photosensitive agent is etched; The stamper is pressed onto the UV curing agent applied to the light guide plate and irradiated with UV to the extent that it is not completely cured, and the UV curing agent is completely cured by irradiating UV in the compressed state or irradiating UV with the stamper separated. The second hologram layer forming method comprising the step of. A method of forming a second hologram layer on a light guide plate used in the lighting apparatus of claim 2 or 7, Enlarging the laser beam emitted from the laser and entering the diffuser; Exposing only a portion of the photosensitive agent to the laser beam by using a blocking plate on the glass plate coated with the photosensitive agent and placed at a distance from the diffusion plate, and then blocking the laser beam; The distance between the glass plate and the diffuser plate is increased, and the area irradiated with the laser beam is covered with a blocking plate, and the portion not irradiated with the laser beam immediately adjacent to the area irradiated with the laser beam is exposed to the laser beam. Repeating the process of blocking the laser beam until the laser beam is irradiated on the entire glass plate coated with the photosensitive agent; Developing the glass plate to etch a photosensitive agent; Electroless plating on the glass plate to form a metal stamper in a form in which a photosensitive agent is etched; The stamper is applied to the UV curing agent irradiated with UV to the extent that it is applied on the light guide plate and not completely cured, and completely cured the UV curing agent by irradiating UV in the compressed state or irradiating UV in a state where the stamper is separated. Hologram layer forming method comprising a. The method of claim 12, In performing the repetition step, the hologram layer forming method, characterized in that the size of the exposed area is made constant each time, or configured to gradually decrease or increase than the first exposed area. As a method of forming the first hologram layer under the light guide plate according to any one of claims 1, 2, 6, and 7, Enlarging the laser beam emitted from the laser and entering the diffuser; Exposing a glass plate coated with a photosensitive agent and having a mask having a pattern shape to be formed on a first hologram layer to the laser beam; Developing the glass plate to etch a photoresist according to a pattern formed on a mask; Making a metal stamper by electroless plating on the glass plate etched with the photoresist; And The stamper is applied to the UV curing agent irradiated with UV to the extent that it is applied on the light guide plate so as not to be completely cured, and completely cured the UV curing agent by irradiating UV in the compressed state or irradiating UV in the state of removing the stamper. Hologram layer forming method comprising a. The method of claim 14, The configuration of the mask is such that the portion where the hologram is to be made transparent and the other portion is opaque to block the light so as to form a negative hologram or the composition of the mask is reversed and the result is positive A hologram layer forming method, characterized in that to form a hologram.