TWI226476B - LCD device - Google Patents

Abstract

The invention targets at providing the LCD device capable of enhancing brightness without increasing the brightness of light source. To achieve the goal, the LCD device of the invention utilizes the light guide plate forming a plurality of small dents (hereinafter called dot) to change the propagation direction of the guided light inside the light guide plate to the designated direction and properly control its surface shape and inclination angle of cross section in addition to installing reflector beneath the light guide plate. Furthermore, install a prism sheet with adequate apex angle, making the illuminating light with proper angle distribution irradiate onto the display component from the light irradiating surface. Moreover, to prevent the generation of moire, let dot allocation meet certain limitation condition and adopt the part formed by random allocation. Besides, by making the dot density as the designated density distribution, the uniform light illumination distribution of the irradiated light can be secured.

Description

1226476 V. Description of the invention (1) Background of the invention The present invention relates to a liquid crystal display device using a member for a liquid crystal display device such as a backlight device (backlight). Description of the Related Art In recent years, with the miniaturization of personal computers, portable types of laptops have gradually become popular. The display of this laptop personal computer usually uses a liquid crystal device. This liquid crystal device is accompanied by a color display in recent years, and a light source is provided behind a liquid crystal display panel, and a backlight device type display device that illuminates the entire display surface from the rear is also in widespread use. The rear device of the display device is so tired that the light source must be high in brightness, and the entire plane must be illuminated without uneven brightness. In order to increase the brightness, it is simple to increase the brightness of the light source, but because of a laptop personal computer, etc. It is driven by using a battery or the like as a driving source, so there is a limit to increasing the brightness of the light source, and there has been no effective method until now. Bureau of Intellectual Property, Ministry of Economic Affairs_Industrial and Consumer Cooperation: Dagger; ·? As a conventional edge-light type lighting device for liquid crystal display elements, it has been disclosed in JP-A-Heisei 4 1 16 2 0 0 2 and JP-A-Hei 6 -Bulletin 6 7 0 0 4. As shown in FIG. 2, a conventional lighting device uses a lamp tube such as a cold-cathode tube or a hot-cathode tube as the light source 1, and this is arranged on an end surface of a light guide plate 2 made of a transmissive material. A light-scattering layer 3 for scattering light and a reflecting plate 4 for reflecting light are provided below the light guide plate 2, and an upper surface of the light guide plate 2 is provided for uniform brightness across the entire surface to make it uniform A diffuser plate 5 made of a milky white synthetic resin having a light scattering effect. Further on top of it, 'make diffused light as a kind of table paper, you can apply the Chinese National Standard (CNS) A 1 specification (210 X 297 mm) -4- 1226476 A / __B7_ "-j V. Description of the invention (2) The first light-concentrating plate 6 and the second light-emitting plate 7 are used to improve the front brightness of the display device. The light-scattering layer is used on the surface of the light guide plate 2 as shown in FIG. 3. A plurality of ink dots 8, such as titanium oxide, are light-scattering substances. The light intensity from the light source 1 is weaker as it is farther from the light source 1. Therefore, the area of the ink dot 8 is as shown in FIG. As described above, in the previous lighting device, the light emitted from the light source 1 was guided to the light guide plate 2 and scattered by the light scattering material 8 including the residual light scattering layer, and The structure that is then irradiated to the liquid crystal element through the diffusion plate has a problem of reducing the brightness due to the loss of light scattering. To solve these problems, there is an ink-free guide as shown in Japanese Patent Laid-Open No. 9-2 6 9 4 8 9 Light plate method. This is to form small bumps on the surface of the light guide plate. Or small recesses to reflect the light and illuminate the liquid crystal element. However, its shape or distribution has not been optimized, and there is still room for improvement in brightness. Furthermore, one of the technical bottlenecks in improving the brightness of liquid crystal display devices 'The transmittance of a polarizing filter can be cited. A polarizing filter is disposed between a liquid crystal cell and a backlight, and is an element having a function of allowing a given polarized light to enter a liquid crystal cell. A polarizing filter is generally, It can be produced by adsorbing a dichroic substance to a molecular cluster tube of a polymer film in which molecular clusters (nncelle or translated into crystals and cells) are arranged in a certain direction. The polymer film here uses polyethylene Alcohol, and this is stretched 3 to 5 times in a certain direction between the rollers at different speeds. The molecular groups of the stretched PVA are aligned in the extension direction, and the aligned film has a strong complex inflection. As i _ (Please read the notes on the back before filling this page)

Each paper & degree applies the Chinese National Standard (CNS) A4 specification (210x297 mm) -5-Λ7 1226476 V. Description of the invention (3) There are halogen substances such as iodine, dyes, etc. to provide dichroism. The above-mentioned substance can be adsorbed on the stretched film to exhibit polarization characteristics. The above-mentioned polarizing filter can easily obtain a function of separating polarized light. Its transmittance is due to the use of a dichroic substance in principle, and it absorbs polarized light that is orthogonal to the transmitted polarized light. Therefore, the transmittance is relatively small below 50%. . In other words, the polarization filter has a light energy loss of 50% or more, and the current situation is that the brightness of the liquid crystal display element is significantly reduced. As a means of improvement, a method using a reflective polarizing film has been proposed. Reflective polarizing films, such as cholesteric liquid crystal films, are films that have the property of passing a specific type of polarizing component and reflecting other polarizing components. In other words, the unpolarized natural light emitted through the light guide plate is incident on the reflective polarizing film, and only a specific polarized component is allowed to pass through, and other polarized components are reflected. After that, the reflected polarized light component is reflected again to change the polarization state and enter the reflective polarizing film again, so that only a specific polarized light component is transmitted. By doing so repeatedly, almost all the components of light can be used. Specifically, as described in JP-A No. 3-4 5 9 06 and JP-A No. 6-2 8 1 8 1 4, it has been proposed to use a reflective cholesteric liquid crystal film with f polarizing film. method. A cholesteric liquid crystal film is composed of an active layer of a polymer material with cholesteric regularity. A cholesteric liquid crystal II film ’is a natural light without polarized light emitted from a light source through a light guide plate.

Position I j: I transmits only the circularly polarized light component in the same direction as the spiral direction of the bile, while ^ | I j reflects the circularly polarized light component in the opposite direction. That is, the structure shown in Fig. 16 is composed of 1 and the reflected circularly polarized light component is reflected again by the reflecting plate and returned. (Please read the precautions on the back before filling in this page) ---- I --- Order ---------

Qin paper is widely applicable to China National Standard (CNS) Al specifications (210 x 297 mm) -6-Printed by TS Fee Cooperative of Intellectual Property Bureau, Ministry of Economic Affairs. 1226476 A7 B7 r---- " " — 5 Explanation of the invention (4) ί The state close to natural light re-enters the cholesteric liquid crystal film. By doing so repeatedly, almost all the components of light can be used. If the 1/4 phase plate is overlapped on the light emitting surface of the cholesteric liquid crystal film here, the circularly polarized light component is converted into linearly polarized light, which can be used as a back light emitting device of a liquid crystal display device. The brightness of a liquid crystal display device using a cholesteric liquid crystal film should theoretically be twice that of a liquid crystal display device using a normal polarizing filter. However, when the combination of the ink dot method light guide plate and the cholesteric liquid crystal film which is now the mainstream is used, loss due to scattering as described above may occur, or reflection through the cholesteric liquid crystal film may be incident on the light guide plate again. The circularly polarized light is lost due to the diffusion and reflection of the ink dots, and the state of the polarized light will be eliminated, so it is not easy to use the emitted light again. In addition, the size of the printed dots is quite large. It is necessary to use a diffusion plate in order to prevent the ink dots from being seen, and the brightness improvement effect becomes worse. When the front brightness is increased and the angle distribution of the emitted light is appropriately combined, the brightness improvement effect is only about 10%. In this regard, as described in Japanese Patent Application Laid-Open No. 9-102209, a light guide plate in which a grating groove is formed on the bottom surface of the light guide plate and a cholesteric liquid crystal film are proposed in combination. This method is suitable, the loss caused by scattering is small, the brightness is high, and the brightness improvement effect is higher than the printing dot. However, the light guide plate forming the grating groove is not easy to control the brightness distribution in the X direction, and it may be expected that the mold processing cost and the date of supply are very problematic. Furthermore, because of the problem of rough surface, soft metal such as brass is often used as a mold material, and there is a possibility that productivity is not high. Furthermore, 'K-degree of the paper can be applied between the grating groove and the liquid crystal cell which are formed periodically. The Chinese National Standard (CNS) A;! Specifications (21〇χ 297 Meal) --- (Please read the back first (Notes to fill out this page)

1226476 A7 B7 Wisdom of the Ministry of Economic Affairs, Industry Bureau, 3 labor costs, cooperation and printing V. Description of invention (5) I think it is easy to produce moire. In addition, the grating groove has a relatively large period, which necessitates the use of a diffusion plate, and there is a concern that the brightness improving effect is further reduced. Combined to increase the frontal brightness and appropriately adjust the angular distribution of the emitted light

In the case of I | sheet, the brightness improvement effect is only about 20%. In the above-mentioned conventional devices, since the light source scatters light from the light source and irradiates the liquid crystal element side, there is a loss in scattering or light absorption caused by the ink, and there is a limit to improving efficiency. In addition, regarding the inkless light guide plate, its shape or distribution is not optimized, and there is still room for improvement in brightness. In the method of combining the light guide plate of the ink dot method and the cholesteric liquid crystal film, the brightness improving effect is only about 10%, which is quite low. The method of combining the light guide plate and the cholesteric liquid crystal film to form a grating groove has a brightness improvement effect of about 20%, but it is difficult to control the brightness distribution or manufacture the light guide plate. SUMMARY OF THE INVENTION The present invention aims to provide a liquid crystal display device that can improve the display brightness without increasing the brightness of a light source, by improving the former drawbacks and improving the former defect. In order to achieve the above object, the liquid crystal display device of the present invention uses a light guide plate formed with a plurality of small recesses (hereinafter referred to as "dots") for converting the traveling direction of guided light in the light guide plate to a specified direction, and then, as appropriate, Control its plane shape and section tilt angle. In addition, a reflecting plate is disposed below the light guide plate. Furthermore, 'equipment with proper apex angle should be equipped as needed -------- order --------- (Please read the precautions on the back before filling this page) No Paper change applies Chinese National Standard (CNSM. 丨 Specifications (210 X 297mm f) 8 1226476 A7 B7 V. Description of the invention (6) Sheets, so that the illumination light with a proper angular distribution from the light exit surface can be directed towards the display The element is irradiated. In order to prevent the occurrence of moire, a member is used in which the arrangement of dots satisfies certain restrictions, and the arrangement is formed randomly. In addition, by making the density distribution of dots a predetermined density distribution, injection can be achieved The brightness distribution of light is made uniform. Furthermore, if necessary, a reflective polarizing film (such as a bile liquid crystal film and a 1/4 phase plate) can be arranged between the light guide plate exit surface and the liquid crystal cell to improve the brightness. Detailed description FIG. 1 shows a three-dimensional light source device of the present invention according to an embodiment of the present invention. In order to change the guided light in the light guide plate to a specified direction of advancement, the small concave point of the table at the bottom of the light guide plate 9 .So The so-called "points" are small recesses formed by the dots ♦ 1 4 as the flat part 1 1 (except for the dot bottom plate exit surface 13 angle below 5 degrees) stored under the light guide plate. (But (See Figure 1 for a small bump, as shown in Figure 1.) Figure 4 illustrates the light guide plate used below. When the light source 1 is approximated to a linear light source, the vertical plate cross section 15, The parallel direction is the X direction 16 and the parallel direction of the light guide plate exit surface 13 is Y. Fig. 5 shows the light trajectory of the guided light of the light guide plate of the present invention. The light from the light source 1 The surface 18 is incident on the light guide diagram as incident light 19 of the light guide plate. As shown in the figure, a plural number is formed on the changing direction of the used surface, as shown in FIG. The plane of the figure is the light guide, but the light guide plate light plate light source side end plate 2 in the vertical direction 17. 2 becomes the guide (please read the precautions on the back before filling this page)

I paper is also applicable to Chinese National Standard (CNS) A: 1 size (210x297 male f) -9-1226476 A7 B7 Employees ’cooperation cooperation with the Ministry of Economic Affairs and the Intellectual Property Bureau V. Description of invention (7) Light guide light 2 0, Advancing toward the other end surface 21, the light guide plate and the light guide plate exit surface 1 3 are repeatedly reflected under the light guide plate. Of the guided light 2, the light 2 3 incident on the point-inclined surface 2 2 is reflected and refracted there near the light guide plate exit surface 1 3, and is emitted from the light guide plate exit surface 1 3 as outgoing light 2 4. Then, the unreflected light becomes a point-slope transmitted light 25, and is reflected by the reflecting plate 4 and then incident on the light guide plate 2 again, and a part of it is emitted from the light exit surface 1 3, and the remaining light becomes the light guide plate guided light 20 again. That is, by appropriately arranging the dots, the guided wave light 20 can be slowly emitted from the light guide plate 2, and the liquid crystal display element can be illuminated. Figure 6 shows the shape of the applicable dots. The shape (hereinafter referred to as a planar shape) of the dot bottom 12 of the present invention that is orthographically projected onto the light guide plate light exit surface 13 is suitable for a substantially rectangular shape, or a substantially rectangular shape with apex rounding 2 6 as shown in FIG. 6. (Hereafter called slightly rectangular). This is because the area of the point reflecting surface 22 can be increased for a circle or a square having the same area as the bottom surface of the point, thereby reducing the number of points. In other words, the degree of freedom of point distribution is also increased, and it is easy to create masks or point coordinate data. In addition, the smoothness of the vertices 2 and 6 has the effect of reducing scattering and improving frontal brightness. In addition, as shown in FIG. 6, when the bottom of the point is approximated by a rectangle, the length of the long side is the point length 2 8 and the length of the short side is the point width 2 9 °. Substantially parallel to the X-square | The reason for this configuration is that the area on the long side of the oblique | surface 3 0 is wider than the point on the short side of the oblique surface 31, so the light from the light source 1 can be reflected efficiently. | (Please read the notes on the back before filling this page)

This paper is generally applicable to the Chinese National Standard (CNS) AU (210x 297 mm) -10-'-1226476 A7 B7 V. Description of the invention (8) (Please read the precautions on the back before filling this page) Point The size of the point length is preferably 8 0 to 8 0 0 // m. The reason is that if the above-mentioned length 28 is larger than 800 // m, when the user of the personal computer looks at the liquid crystal display device, the shape of the dots formed on the light guide plate may be seen with different characters or patterns. (You can see the status of the points) ', which hinders the discrimination of characters and figures. In addition, if the above length 2 8 is smaller than 8 0 // m, the number of points is too much. You need to make a mask or create point coordinate data. It becomes difficult. Considering the cost of making the mask, it is most suitable to be more than 1000 // m, and considering the display quality, it is better to be less than 3 0 // // m. The dot width 2 9 is preferably below 6 0 // m. The reason is that if the above-mentioned length 2 9 is larger than 6 0 // m, the ratio occupied by the point inclined surface 14 in the midpoint area will decrease, and it will become difficult to obtain a sufficient reflecting surface. Furthermore, in order to obtain sufficient brightness at the four corners of the light guide plate 2, it is preferable that the above-mentioned length 2 9 be 4 5 // m or less. In addition, regarding the lower limit, it also becomes a problem of the accuracy of the photoresist of the mask and the exposure machine, and it is preferable to use an inexpensive mask or an exposure machine that is more than 20 / m. It is more preferably 30 μm or more. The member of the Smart Finance Bureau of the Ministry of Economic Affairs and the Consumer Cooperatives, the depth of ¾ points is 5 ~ 2 0 // m is appropriate. The reason is that a photoresist with a viscosity regime must be used in order to obtain Zhu Du 'above 2 0 // ni, which will cause the flatness of the flat portion of the dot formation surface to be reduced, or the transferability to be lowered when the light guide plate 2 is formed. It is difficult to form the desired dot shape. On the other hand, if the depth angle 5 // m of the dot is shallow, the ratio of the occupied dot area of the dot slanted surface 14 is reduced, and the desired brightness cannot be obtained. Taking into account the use of a liquid photoresist, the above thickness is 6 ~ 1 2 // m is the most appropriate. This paper is also applicable to the Chinese National Standard (CNS) A "1 specification (210 X 297 mm) -11 -1226476 A7 B7 V. Description of the invention (9) 〇 The inclination angle of the cross section of the present invention is preferably 20 to 35 °, and the most appropriate is 2 8 ± 4. . Here, the inclination angle of a cross section is demonstrated using FIG. Fig. 7 shows the cross-sectional shape of the cut surface of the point where the center of the passing point is parallel to the cross section 15 of the light guide plate in Fig. 4. The reason why such a section is determined is because the inclined surface 30 of the long side of the point acts more effectively than when the path of light is changed; s Buchi i calculates the slope angle of the section by the following method: . As shown in Fig. 7, the point depth is divided into three parts, and the intersections of the three-part line and the inclined surface on the light source side are set to PI, P2, P3, and P4, respectively. Next, the angle between the straight line 3 2 passing through P 2 and P 3 and the point bottom surface 12 is obtained, and this is taken as the cross-section inclination angle. The definition of the tilt angle of the profile as described above is because this angle is easily affected by the error of the processing program conditions and is easy to use for management, and this part also has a great influence on the light emission efficiency. The reason why the tilt angle of the cross-section calculated as described above is specified in the above range is to optimize the emission angle distribution of the light from the light exit surface 13 of the light guide plate while suppressing the amount of light emitted from the tilt to increase the frontal brightness. In other words, if the cross-section inclination angle exceeds 35 °, the ratio of the total reflected light at the point slope decreases and the efficiency decreases. In addition, if it is smaller than 20 °, the angle between the light reflected on the point slope and the exit surface of the light guide plate is not large enough, so that the exit angle of the exit light becomes large and the efficiency is reduced. In the present invention, the cross-sectional shape of the point perpendicular to the direction of the light source is preferably such that the bottom of the point is substantially straight. This is because by forming a straight line, you can reduce the slope and gentle slope and reduce unnecessary reflections. (Please read the precautions on the back before filling this page) --------- Applicable to China National Standard (CNS) A1 size (210 X 297 mm) for clothing paper size -12- 1226476 A7 B7

I-Consumer Cooperation, Intellectual Property Bureau, Ministry of Economic Affairs, Jiangyin K. Invention Description (10) Designed by Gu Yi. As described above, by optimizing the small recesses, the brightness can be increased by more than 10% compared with the circular dots and square dots, and the brightness can be increased by more than 20% compared with the ink dots. In the present invention, the light is induced outside the light guide plate 2 by the reflection and refraction caused by the inclined surface of the point, and the regular reflection of other parts is used to make the light cross every corner of the light guide plate 2. That is, by reducing the surface roughness of the inclined surface portion of the light guide plate, the loss at the time of reflection and refraction can be reduced, and the brightness can be improved. Since the surface roughness of the flat portion of the light guide plate is smaller than that of the inclined surface portion, it is important to suppress the surface roughness of the inclined surface portion in particular. Fig. 8 shows the relationship between the surface roughness and the brightness of the front surface of the inclined surface of the point of the light guide plate (the inclined surface between P2 and P3). As such, R a is preferably 0.4 or less / m. The density of the dots is preferably the smaller the dot density as it approaches the light source 1 in order to make the luminance distribution uniform. Specifically, the length of the light guide plate 17 in the γ direction is 19 lmm ± 2 mm, the thickness of the light incident portion of the light guide plate 2 is 2.3 mm ± 0.5 mm, and the light guide plate 2 is farthest from the light source 1. When the thickness of the part is 1.3mm and 0.3mm, the distribution in the γ direction at the center of the light guide plate is as shown in Fig. 9 (Υ = distance from the light source / length of the light guide plate Υ direction), at 0.05 &lt; Υ & lt In the range of 0.9 to 5 ', the effective area of reflection is better than the range of 3 to 3 shown by hatching. Specifically, within the range of 0.0 5 &lt; Y &lt; 0.95 'to satisfy KlΥ5 + K2Υ4 + K3Υ3 + K4Υ2 + K5Υ1 + K6 + C 1 &lt; Reflection effective area ratio <KiYS + KzYd + KsY3. (Please (Read the notes on the back before filling out this page)

The watch silver Zhangye 1 applies the Chinese National Standard (CNS) A 丨 specifications (210 X 297 mm) -13-1226476 A7. The reflection effective area ratio is determined by the way κ 2 = +0.7497230, κ 4 = +0.1875481, κ 6 = +020298941, C 2 = +0.004 〇B7 V. Description of the invention (11) Υ2 + ΚδΥ1 + Κθ + 〇 Wherein, κ 1 = -0.2330335 ^ κ 3 = -0.6375126, κ 5 = -0.0011018,

C 1 — -0.004 J By having such a distribution of the reflection effective area ratio, it is possible to obtain uniform brightness across the entire liquid crystal display device. At this time, the reflection effective area ratio is calculated using (Expression 1). The reason for using the entire reflection effective area ratio to the specified point density distribution is as shown in Fig. 6 as the long side bevel of the point farther from the light source 1 or the point bottom surface 1 2 or the point short side bevel 3 1. With the function of taking out light, it is easier to make design changes when the size or shape of the dots is changed than when the dot density or dot occupancy is simply used. Reflection effective area ratio = (point length x point height / sin (section tilt angle) x number of points per unit area) / unit area ... (Equation 1) The plane configuration of the points is Random configuration is better. The reason is that the point of the present invention is very small, and in order to prevent interference with other elements constituting a liquid crystal display device such as a liquid crystal cell, a color filter film, a TFT pattern, and a black pattern, moire is generated. Backlighting device combining the light guide plate of the present invention with a reflective polarizing film (cholesteric liquid crystal thin film Θ and a 1/4 phase plate), and a light guide plate using ink dots, a bile liquid crystal film, and a 1/4 phase plate Back lighting equipment ------- I--II — — — — — — — I— ^ — — — — — — — — I— (Please read the notes on the back before filling out this page) Wisdom Section, Ministry of Economic Affairs Members of the production bureau 丄 consumer cooperation prostitutes ^ '-' .. !! ::,: 1226476 A7 V. Description of the invention (12), or a combination of a light guide plate and a bile retention liquid crystal 溥 fl 旲 and a 1/4 phase plate Compared with the back lighting device, the brightness improvement effect is great. Furthermore, the light guide plate of the present invention is easier to manufacture than the light guide plate forming the grating groove, so it is preferable to combine the light guide plate of the present invention with a cholesteric liquid crystal film and a 1/4 phase plate. Hereinafter, embodiments of the present invention will be described with reference to the drawings. Economic, financial and financial cooperation (First Embodiment) Fig. 1 is a perspective view of a liquid crystal device used in the present invention. Fig. 6 is a dot diagram of the embodiment. In this embodiment, the dot length 2 8 is 2 // 40 / m, and the dot depth is 8 / zm. The light guide plate 2 and the reflection plate 4 are the minimum structures, and dots are formed below them. In addition, the point system is arranged as shown in FIG. 10. With the generation of. In addition, in this embodiment, except for the diffuser plate and the two condenser plates. Figure 11 shows the state of manufacture in the example. The inclination angle of the profile is 2 8 °. The inclination angle of the 12th surface and the average brightness of the light guide plate. From the angle of inclination, it is appropriate to use 0 to 35 °. The 13th figure shows the reflection effective area of the display point (second embodiment). The shape of the back-illuminating device (small recessed part) of the display device is 00 / im, and the point width 29 The backlight device is based on the light source and is arranged on the light guide plate 2. Part of this configuration can prevent moire. The point section shape of the light guide plate 2 used in addition to the minimum constituent elements is shown in the section of this embodiment. Figure 12 shows that the appropriate point section is 28 ± 3 °. Than distribution. (Please read the note on the back? Matters before filling out this page) ____ ^ Paper &lt; .Change to Chinese National Standard (CNS) / U specifications (21〇x 297 mm 15 1226476 A7 V. Description of the invention (13) Fig. 17 is a structural diagram of a liquid crystal display device using a cholesteric liquid crystal film. Fig. 17 compares and reviews the case where the light guide plate of the present invention is used on a light guide plate (second embodiment), and the guide of the combined ink dot method is reviewed. In the case of a light plate (the first comparative example), and in the case of a light guide plate combined with a grating method (the second comparative example), FIG. 18 shows the brightness distribution in the X direction and the Y direction of the second embodiment. And the brightness distribution in the X direction and the Y direction when the cholesteric liquid crystal film and the λ / 4 plate are removed by the structure of the second embodiment. The brightness improvement effect is about 20% in both the X direction and the Y direction. Figure 19 shows the brightness distribution in the X and γ directions of the first comparative example, and the X and Υ directions in the case where the cholesteric liquid crystal film and the λ / 4 plate are removed by the configuration of the first comparative example. Brightness distribution map. Brightness is about 10% in X direction and Υ direction. Figure 20 shows the brightness distribution in the X-direction and the Y-direction of the second comparative example, and the X-direction and the case when the cholesteric liquid crystal film and the λ / 4 plate are removed by the configuration of the first embodiment. Diagram of the brightness distribution in the Υ direction. Both the X direction and the Υ direction have a brightness improvement effect of about 20%. In this way, the use of the light guide plate of the present invention has a more cholesteric liquid crystal film than the ink dot light guide plate. Brightness improvement effect. In addition, it has the same brightness improvement effect as the light guide plate using the grating method. Furthermore, the reliability of the liquid crystal display device using the light guide plate of the present invention is high for the ink dot method even when a cholesteric liquid crystal film is not used. It is more than 10%, which is equal to or better than the grating method. Furthermore, the grating method has many problems in terms of uniformity of in-plane brightness and difficult manufacturing of the mold. (Fill in this page again) Through the wisdom of the sub-branch, the production bureau member X consumes cooperation ¾.

The paper size of the table applies the Chinese National Standard (CNS) A4 specification (210 X 297 male f)-16-1226476 A7 5. The invention description (14) is better. Table 1 lists the liquid crystal display device of the present invention and the liquid crystal display device of the above comparative example with and without a cholesteric liquid crystal film. Table 1 Comparison of various methods

Liquid crystal display device 2nd example 1st comparative example Ink dot method 2nd comparative example Grating method reflective polarizing film ※ 1 &gt; fnr ΙΙΙΓ J \\\ Yes M Yes M ^ \\\ Yes Front brightness ※ 2 111 135 100 108 110 132 Problems in mass production 4ffL Μ te J \ NN Μ j \\\ Μ J \ w Difficulty in correcting the brightness distribution in the X direction Difficult cost in mold manufacturing ◎ 〇〇Δ XXX Judgment 〇〇Δ XX Steroid liquid crystal film * 2 The relative brightness when the brightness of the polarizing film without ink dots is 100. Therefore, the light guide plate according to the present invention has the same brightness as a liquid crystal display device using a conventional ink dot method and a cholesteric liquid crystal film. , Better in cost. Furthermore, in cases where high brightness is required, the paper size is combined with the Chinese National Standard (CNS) A4 specification (210 X 297 mm). (Please read the precautions on the back before filling this page)

I r1 Pack. Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs -17- Economy; Printed by the Consumers’ Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. 1226476 A7 V. Description of the invention (15) The liquid crystal display device is optimal. The same effect can be obtained by using a reflective polarizing film other than a cholesteric liquid crystal film. Next, a method for manufacturing a light guide plate for a backlight device according to the present invention will be described. The manufacturing method of the light guide plate is to make a mold and make plastic. The number of dots in the small recesses of the light guide plate is as large as 500,000 to 2 million on a 12 · 1 inch light guide plate, so it is preferable to apply the following manufacturing method. Figure 14 shows the procedure of this manufacturing method. This manufacturing method is characterized by including: (1) a process of forming a photoresist 3 5 on a substrate, (2) arranging a light mask 3 6 having a pattern of dots on the substrate 3 4 'from above the mask 3 6 After irradiating ultraviolet rays 37, the photoresist is developed to form a dot pattern on the substrate 34. (3) The pattern is plated to form a stamper 39 composed of a plating layer 38. (4) a process of plastically forming the light guide plate 2 by using the above-mentioned stamper 39. Here, as the substrate 34, a mirror-honed glass plate or the like is used. Prior to the formation of the photoresist 35, a silane-based adhesion promoter may be applied in advance. As the photoresist material, liquid or film-shaped positive and negative materials can be used. For the formation method, a spin coating method, a roll coating method, or the like can be used. The depth of the small recess can be changed by controlling the thickness of the photoresist. In addition (Please read the notes on the back before filling out this page)

K degree of clothing paper is applicable to Chinese National Standards (CNS) A Regulations (210 X 297 mm) -18- 1226476 A7 The wisdom of the Ministry of Economic Affairs and the cooperation with the staff of the Production Bureau: Weiyinhe B7 V. Description of the invention (16), The section tilt angle can be controlled by carefully controlling the exposure, development, and annealing conditions. Various types of masks such as chrome masks, film masks, and emulsion masks can be used for the light mask 36. Data such as the size, number, and distribution of dots designed in advance can be created in advance. Electronic wires, laser beams, etc. To paint. Before the electroplated layer 38 is formed, a conductive film is formed in advance, so that there is no uneven plating, and a good electroplated layer 38 is formed, that is, a stamp 3 9. As a material of the conductive layer and the plating layer, various metals can be used. Considering uniformity and mechanical properties, nickel is the most suitable material. The obtained electroplated layer 38 can be easily physically peeled from the substrate 34, and it is necessary to use honing and polishing as the stamp 39. The obtained stamp 39 is fixed to the mother mold of the injection molding machine with a magnet, a vacuum clamp, or the like, and the light guide plate 2 is formed by plastic molding. In the above description, the method of manufacturing the light guide plate 2 by the injection molding machine has been shown, but other methods' may be used to manufacture the light guide plate 2 by methods such as extrusion molding, compression molding, and vacuum molding. As a material constituting the light guide plate 2, all transparent plastic materials can be used. Specific examples include materials such as acrylic plastics, polyethylene carbonate resins, polyacetal resins, polyurethane resins, and UV-curable plastics. Among them, acrylic materials are superior in terms of transparency, price, moldability, etc., and are suitable for the present invention. Next, the configuration of a liquid crystal display device will be described. The main structure of the liquid crystal display device of the present invention is as follows: A polarizing plate, a liquid crystal cell, a common electrode, a color filter, and a polarizing plate are provided on the surface lighting device. This structure is a liquid crystal display device (please read the precautions on the back before filling this page)

1226476 A7 ----- B7___ V. In the general example of the description of invention (17), as the display device is used differently, various configurations can be considered including the backlight device. For example, a desktop liquid crystal display device of a personal computer or a television screen is particularly required to have a wide viewing angle. In this field ', a diffuser plate with an enlarged viewing angle for scattering the illumination light can be arranged at an appropriate position. In addition, after arranging a thin sheet, and then irradiating the liquid crystal cell with higher directivity illumination, a sheet having a light diffusion effect is arranged in order to expand the viewing angle, and the light emitting surface can be processed to have a light scattering function to extend the viewing angle. . Specific examples of the light source 1 include a cold cathode tube, a hot cathode tube, a tungsten light bulb, a halogen bulb, and a gas bulb. Generally, a low-temperature light source such as a cold cathode tube is preferred. The liquid crystal element or liquid crystal cell used in the present invention is not particularly limited, and a known element or panel can be used. Common liquid crystal cells include twisted filament type, super twisted filament type, equal type, and thin film transistor type. In addition, there are active matrix drive type and simple matrix drive type. The reflective polarizing film used in the present invention is not particularly limited, and a known film such as a cholesteric liquid crystal film can be used. Specifically, for example, D B E F (trade name) manufactured by 3M Company or TI * an s m a X (trade name) manufactured by Melco (transliteration) can be used. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs As described above, with the liquid crystal display device of the present invention, a liquid crystal display device with multifunctional and high-performance, improved brightness, no uneven brightness, and stable characteristics can be obtained. Brief Description of the Drawings Figure 1 shows the back-illuminating device using the liquid crystal display device of the present invention. $ Paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) &quot; A7 1226476 B7 Γ --- ~- -V. A perspective view of invention description (18). Fig. 2 is a cross-sectional view of a light guide plate using a conventional dot printing method. Fig. 3 is an explanatory diagram of a conventional dot printing method. FIG. 4 is an explanatory diagram of a cutting direction of the light guide plate. Fig. 5 is a diagram for explaining a light path in the light guide plate used in the light guide plate of the present invention. Fig. 6 is an explanatory diagram of a dot shape used in the light guide plate of the present invention. Fig. 7 is an explanatory view of a cross-sectional inclination angle of a light guide plate used in the present invention. Fig. 8 is a graph showing the relationship between the surface roughness r a and the front brightness of the light guide plate used in the present invention. Figure 9 is a point reflection effective area ratio distribution diagram used in the light guide plate of the present invention. Fig. 10 is an explanatory diagram of a random arrangement of a light guide plate used in the present invention. FIG. 11 is an explanatory diagram of a cross-sectional inclination angle of the light guide plate used in the present invention. Fig. 12 is a diagram showing the relationship between the inclination angle of the cross section of the light guide plate used in the present invention and the front brightness. Fig. 13 is a distribution diagram of point reflection effective area ratio used in the light guide plate of the present invention. Fig. 14 is a process drawing showing a method of manufacturing a light guide plate used in the present invention. Fig. 15 is a configuration diagram of a liquid crystal display device of the present invention. »_ 6 papers <CNC A1 Secret Food> -21-'(Please read the precautions on the back before filling this page) II — 丨 丨 Order- 丨 ―. 丨 — 丨— I- Consumption Cooperation between Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs and Consumer Affairs Bureau of the Ministry of Economic Affairs and Consumer Affairs: Consumption Cooperation:-;.:-: 1226476 A7 B7 V. Description of the Invention (19) Figure 16 shows the use of a cholesteric liquid crystal film. An explanatory diagram of the principle of a liquid crystal display device. Fig. 17 is a configuration diagram of a liquid crystal display device using a bile-liquid thin film. Fig. 18 is an explanatory diagram of the effect of the bile liquid crystal film of the second embodiment of the present invention. Fig. 19 is an illustration of the effect of the cholesteric liquid crystal film of the first comparative example. Fig. 20 is an explanatory diagram of the effect of the cholesteric liquid crystal film of the second comparative example. DESCRIPTION OF SYMBOLS 1 Light source 2 Light guide plate 4 Reflective plate 9 Below the light guide plate 10 points 11 Flat portion 12 points Bottom 13 Light guide plate exit surface 14 Point oblique portion 15 Light guide plate section 16 X direction 17 Y direction -------- ^ --------- (Please read the precautions on the back before filling this page) The size of the paper is applicable to the Chinese National Standard (CNS) A 彳 specification (21〇X 297 mm) -22- 1226476 A7 B7 I 1 ...... '........ ~ ........ ..... ..... ... I. V. Description of the invention ( 2〇) 18 Light guide plate light source side end surface 19 Light guide plate incident light 2 0 Light guide plate guided light | I 2 1 End face 22 point inclined surface 2 3 Light 2 4 Emitted light 2 5 Point inclined light transmitted 2 2 Smooth point at the vertex 2 8 Dot length 2 9 Dot width 30 Dot bevel on the long side 31 Dot bevel on the short side ------------- Install -------- Order --------- (Please read the precautions on the back before filling out this page) 孓 The paper is again applicable to the Chinese National Standard (CNS) A4 specification (21〇χ 297 公 f) -23-

Claims (1)

1226476 A8 B8 C8 D8 VI. Application for Patent Scope No. 88102877 Patent Application Chinese Application for Amendment of the Patent β Amendment on March 10, 1992 1 · A liquid crystal display device with a light guide plate and a side disposed on the light guide plate The light source, the two light-collecting reflectors disposed on the top surface of the light guide plate, the liquid crystal display panel disposed on the top surface of the light guide plate, and the reflective plate disposed on the bottom surface of the light guide plate are characterized in that: The bottom surface of the light guide plate is substantially parallel to the surface of the liquid crystal display panel. The bottom surface of the light guide plate has small recesses. The planar shape of the small recesses is slightly rectangular. The range of 8 0 to 8 00 // m, the length perpendicular to the direction of the light source is less than 6 0 // m, the depth of the small recess is in the range of 5 to 2 0 # m, and the inclination angle of the cross section of the small recess is 2 0 ~ 3 5 °, and the surface roughness of the inclined surface of the small concave portion is Ra &lt; 〇. 4 # m. 2. The liquid crystal display device according to item 1 of the scope of patent application, wherein the distribution of the small recesses is in the range of 0.0 5 &lt; Y &lt; 0.9 5 when the reflection effective area ratio Y == distance from the light source / length of the light guide plate Y. Within the range, K 1 Y 5 + K 2 Y 4 + K 3 Y 3 + K 4 Y 2 • + K 5 Y 1 + K 6 + C 1 &lt; Reflective effective area ratio &lt; K 1 Y! 5 + K 2 Y 4 + K 3 Y 3 + K 4 Y 2 + K 5 Y 1 + K 6 + C 2; Among them, K 1 = -0.2330335, 1 K 2 +0.7497230, K 3 -0.6375126 = 1 This paper size is applicable to China Standard (CNS) Α4 specification (210 × 297 mm)-* -------- ^ 1 &quot; equipment-(Please read the precautions on the back before filling this page), tT. Intellectual Property Bureau, Ministry of Economic Affairs Printed by employee consumer cooperative 1226476 A8 B8 C8 D8 々, patent application range K 4: = + 0.1875481 K 5: = -0.0011018 K 6: = + 020298941 C 1 = -0.004, C 2 = + CL004 0 (Please read the back first (Please pay attention to this page before filling in this page) 3. If the liquid crystal display device in the first scope of the patent application, the arrangement of the small recesses is random. 4. The liquid crystal display device according to item 1 of the scope of patent application, wherein the cross-sectional shape of the small recessed portion perpendicular to the direction of the light source, and the bottom of the small recessed portion is substantially straight. 5. The liquid crystal display device according to item 1 of the patent application scope, wherein at least a reflective polarizing film is disposed on the light guide plate exit surface side of the light guide plate. 6. The liquid crystal display device according to item 1 of the scope of patent application, wherein at least a cholesteric liquid crystal film is arranged on the light guide plate exit surface side of the light guide plate. 0 Printed by the employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 7. In the liquid crystal display device of claim 1, at least a cholesteric liquid crystal film and a 1/4 phase plate are arranged on the light guide plate emitting surface side of the light guide plate. This paper size applies to China National Standard (CNS) A4 (210X297 mm)