JP4379077B2 - Backlight unit and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a light guide plate and a reflection sheet from sticking to each other due to the change of an environment or the like resulting in the deterioration of a display property such as luminance unevenness. <P>SOLUTION: The structure of a backlight unit comprises a light guide plate 2 which guides inside light incident from a light source and emitted from a first face 21 and reflection sheets which are arranged opposed to each other adjacent to the first face 21 of the light guide plate 2 and a second face 22 on the opposite side. A plurality of fine projections 24 are formed on the second face 22 of the light guide plate 2 in area forms, and thereby the light guide plate 2 and the reflection sheet are prevented from sticking to each other. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

  The present invention relates to a backlight unit and a liquid crystal display device using the same, and more particularly to a backlight unit that emits light from the back side of a liquid crystal panel unit and a liquid crystal display device using the same.

  2. Description of the Related Art In recent years, liquid crystal display devices are mounted on various electronic devices ranging from personal computers, PDAs (Personal Digital Assistants), portable information terminals such as mobile phones, and home appliances such as video cameras and digital cameras. In general, in a liquid crystal display device, since the liquid crystal itself does not emit light, a backlight unit is used as a light source unit for displaying an image brightly.

  Backlight units are roughly divided into an area light system (direct system) in which a light source is arranged directly under the liquid crystal panel unit and an edge light system (light guide plate system) in which a light source is disposed at the edge (edge) of the light guide plate. It is properly used according to the purpose. In particular, the edge light method can reduce the thickness of the backlight unit compared to the area light method, heat from the light source is less likely to be transmitted to the liquid crystal panel unit, and a uniform surface light source is obtained. Luminance due to lamp deterioration and lot variation There is an advantage that the spots are not easily recognized.

  The edge light type backlight unit includes a light source, a light guide plate that guides light incident from the light source and emits the light to the first surface side (liquid crystal panel unit side), and the first surface side of the light guide plate. And a plurality of optical sheets arranged in a laminated state, and a reflection sheet arranged close to and opposed to the second surface opposite to the first surface of the light guide plate. As a liquid crystal display device employing such an edge light type backlight unit, one described in Patent Document 1 below is known.

Japanese Patent Laid-Open No. 2002-75038 (FIG. 1)

  However, the conventional edge light type backlight unit has the following problems. That is, when the environment changes to a low temperature, high temperature, low humidity, high humidity, or a specific atmosphere that combines them, or when an environmental change occurs from such a specific atmosphere to a normal temperature and normal humidity atmosphere, and further from the normal temperature and normal humidity atmosphere There may be a phenomenon in which the light guide plate and the reflective sheet partially stick under various environmental conditions, such as when the environment changes to the atmosphere. In this case, according to the difference in the physical constants of each component, the dimensional change of the component due to temperature change or moisture absorption occurs in a state where the light guide plate and the reflection sheet are partially attached. A shape distortion may occur in the reflection sheet at the non-sticking portion, and partial luminance unevenness may appear on the display screen due to the distortion. Such luminance unevenness is a factor that greatly deteriorates the display characteristics of the liquid crystal display device.

  Therefore, as a means for preventing the light guide plate and the reflection sheet from sticking, it is conceivable to secure a sufficient gap between the light guide plate and the reflection sheet, but in this case, the thickness of the backlight unit increases, This is disadvantageous in reducing the thickness. In addition, as another method, it is possible to fix the reflective sheet to the backlight frame etc. with double-sided tape and forcibly prevent sticking, but in this case, it involves adding parts and adding pasting costs, Product costs will increase.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to prevent the light guide plate and the reflection sheet from sticking to each other without causing a reduction in thickness and cost of the backlight unit. A backlight unit and a liquid crystal display device using the backlight unit are provided.

The backlight unit according to the present invention opposes a light guide plate that internally guides light incident from a light source and emits the light from the first surface, close to the second surface opposite to the first surface of the light guide plate. And a plurality of minute protrusions provided on the second surface of the light guide plate, the light guide plate is formed with a dot formation region in which a large number of dots are formed, and non-dot formation in which the dots are not formed The plurality of microprotrusions includes a first microprotrusion disposed in the dot formation region and a second microprotrusion formed in the non-dot formation region, and The second microprotrusions are arranged more densely than the first microprotrusions . Further, the liquid crystal display device according to the present invention uses the backlight unit having the above configuration.

  In the backlight unit having the above-described configuration and the liquid crystal display device using the backlight unit, a plurality of minute protrusions are interposed between the light guide plate and the reflection sheet by providing a plurality of minute protrusions on the second surface of the light guide plate. It will be in the state. For this reason, the relative approaching movement between the light guide plate and the reflection sheet is prevented by each minute protrusion.

  According to the present invention, the light guide plate and the reflection sheet are attached to each other under various environments such as high temperature, high temperature and high humidity, and low temperature by providing a plurality of minute protrusions on the second surface of the light guide plate. It is possible to reliably prevent the deterioration of display characteristics such as luminance unevenness. Thereby, the environmental resistance of the backlight unit used for a liquid crystal display device can be improved significantly. Further, in order to prevent sticking between the light guide plate and the reflection sheet, additional parts such as double-sided tape and labor costs such as pasting are not required, so that the product cost does not increase.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The liquid crystal display device according to the present invention is mainly composed of a liquid crystal panel unit and a backlight unit. The liquid crystal panel unit, for example, sandwiches a liquid crystal layer in which color filters, transparent electrodes, alignment films, liquid crystals, alignment films, transparent electrodes, etc. are stacked in order between two panel substrates (glass substrates) and deflects them outside An optical film such as a film or an antireflection film is arranged. In this liquid crystal panel unit, only light amount modulation of light passing therethrough is performed in the liquid crystal cell, so that the liquid crystal panel unit itself does not emit light. Therefore, some kind of light source is required to display an image (image) on the liquid crystal panel, and a backlight unit is used as a light source unit for that purpose.

  FIG. 1 is an exploded perspective view showing a configuration example of a backlight unit used in a liquid crystal display device according to an embodiment of the present invention. The illustrated backlight unit employs an edge light system, and roughly includes a plurality of white LEDs (Light Emitting Diodes) 1, a light guide plate 2, a plurality of optical sheets 3, and a reflection sheet 4. It is configured with. The number of white LEDs 1 and the sizes of the light guide plate 2, the optical sheet 3, and the reflection sheet 4 can be appropriately changed according to the size (panel size) of the liquid crystal panel unit to be irradiated with light.

  Several white LED1 is arrange | positioned at the end surface 20 of the light-guide plate 2 as a primary light source. Each white LED 1 is mounted on a flexible printed wiring board (hereinafter referred to as FPC) 5 and arranged in a line on the FPC 5. As the primary light source, a cold cathode fluorescent lamp can be used instead of the white LED 1.

  The FPC 5 is provided with a connector insertion portion 6 integrally therewith, and the LED light emission power is supplied from the outside via the connector insertion portion 6. In addition, a reflector 7 having a U-shaped cross section may be set on the mounting portion of the white LED 1 of the FPC 5 so as to efficiently reflect the light emitted from each white LED 1 toward the light guide plate 2 side.

  The light guide plate 2 is for uniformly emitting the light incident from the end face 20 of the light guide plate 2 to the outside while guiding the inside of the light guide plate 2. The light guide plate 2 is formed of a resin molded product having optical transparency. The light guide plate 2 includes a first surface (light emitting surface) 21 that emits light toward a liquid crystal panel unit (not shown), and a second surface 22 opposite to the first surface 21. The first surface 21 side of the light guide plate 2 is disposed so as to face the liquid crystal panel unit. The second surface 22 of the light guide plate 2 is formed with a number of dots or prism-shaped grooves (not shown) that scatter incident light. (Hereinafter, dots will be described as a typical example of scattering light.) The interval between the dots is determined by a light source (in order to equalize the amount of light emitted from the first surface 21 of the light guide plate 2 in the plane). It is set to become denser as the distance from the white LED 1) becomes longer. Such dots may be formed on both the first surface 21 and the second surface 22 of the light guide plate 2.

  A plurality of optical sheets 3 diffuse and collect light incident thereon to form a surface light source. For example, a combination of a lens sheet (prism sheet) and a diffusion sheet, or a brightness enhancement sheet added thereto Composed of a combination. Each optical sheet 3 is arranged on the first surface 21 side of the light guide plate 2 in a laminated state (a state where they are overlapped with each other).

  The reflection sheet 4 is a thin sheet having a high reflectance (for example, ESR manufactured by Sumitomo 3M Limited), and is disposed in close proximity to the second surface 22 of the light guide plate 2. In the assembled state of the backlight unit, a predetermined gap (for example, 0.05 to 0.15 mm) is secured between the light guide plate 2 (second surface 22) and the reflection sheet 4. The reflection sheet 4 directs the light guided from the end surface 20 of the light guide plate 2 to the second surface 22 side of the light guide plate 2 toward the first surface 21 side of the light guide plate 2. reflect.

  In the backlight unit configured as described above, when the connector insertion portion 6 of the FPC 5 is electrically connected to a power supply terminal (not shown) and each white LED 1 emits light by the power supplied through the connector insertion portion 6, this emitted light Is incident on the inside of the light guide plate 2 from the end face 20 of the light guide plate 2. At this time, light is scattered by dots appropriately formed on the second surface 22 side (reflective sheet 4 side) of the light guide plate 2, and part of the light is scattered on the first surface 21 side (optical sheet 3 side) of the light guide plate 52. The other part propagates inside the light guide plate 2 and the other part further advances to the second surface 22 side (reflective sheet 4 side) of the light guide plate 2.

  Among these, the light that has traveled to the second surface 22 side of the light guide plate 2 is reflected by the reflective sheet 4 to the first surface 21 side of the light guide plate 2. Moreover, the light (including the light reflected by the reflection sheet 4) that has traveled to the first surface 21 side of the light guide plate 2 is appropriately diffused by the diffusion sheet of the optical sheet 3 to become uniform planar light. The light is condensed by the lens sheet of the sheet 3 and irradiated to a liquid crystal panel unit (not shown).

  2A and 2B show the structure of the light guide plate employed in the backlight unit according to the embodiment of the present invention. FIG. 2A is a plan view when the light guide plate is viewed from the reflection sheet side, and FIG. FIG. As illustrated, a plurality of recesses 23 are formed on the end surface 20 of the light guide plate 2. In each recess 23, the corresponding white LED 1 (see FIG. 1) is arranged in a 1: 1 relationship. Further, when the light guide plate 2 is viewed in plan, the second surface 22 of the light guide plate 2 includes a dot formation region E1 where a large number of dots are formed and a non-dot formation region E2 where dots are not formed. It is divided into.

  On the other hand, on the second surface 22 of the light guide plate 2, a plurality of minute protrusions 24 are arranged in an area shape over the entire surface (including the dot formation region E1 and the non-dot formation region E2). Each microprotrusion 24 is integrally formed with the light guide plate 2 and is formed in a cylindrical shape on the second surface 22 of the light guide plate 2, and protrudes from the second surface 22 of the light guide plate 2 in the thickness direction of the light guide plate 2. It is provided in the state. The microprotrusion 24 is a microprotrusion having a size that is not recognized as a white spot or the like on the liquid crystal panel. For example, when the panel size of the liquid crystal panel is 2.5 inches, the outer diameter dimension (diameter) φD of the minute protrusion 24 is about 0.2 mm, and the height dimension (projection dimension from the second surface 22) H is about 50 μm. Set to

  Further, on the second surface 22 of the light guide plate 2, the surface of the dot formation region E1 is formed in a fine uneven shape due to the presence of dots, and the surface of the non-dot formation region E2 is formed smoothly because there are no dots. . In contrast, in the present embodiment, the minute protrusion 24 formed in the dot formation area E1 is used as the first minute protrusion 24A, while the minute protrusion 24 formed in the non-dot formation area E2 is the second minute protrusion 24B. As a result, the second minute protrusions 24B are arranged more densely than the first minute protrusions 24A.

  Incidentally, the light guide plate 2 is obtained by resin molding using a molding die. Therefore, if a minute recess corresponding to the plurality of minute protrusions 24 is formed on the mold surface for molding the second surface 22 of the light guide plate 2, the plurality of minute protrusions 24 are provided on the second surface 22 as described above. The light guide plate 2 can be obtained.

  By configuring the backlight unit using the light guide plate 2 as described above, on the second surface 22 side of the light guide plate 2, as shown in FIG. A plurality of minute protrusions 24 are interposed in the portion), and the gaps G are always secured between the two (2, 4) by these minute protrusions 24. Therefore, even when an environmental change such as temperature and humidity occurs, the relative approaching movement (displacement) between the light guide plate 2 and the reflection sheet 4 is prevented by the contact between the reflection sheet 4 and the minute protrusions 24. Therefore, sticking between the light guide plate 2 and the reflection sheet 4 due to environmental changes can be reliably prevented, and deterioration of display characteristics such as luminance unevenness can be avoided.

  In addition, a plurality of minute protrusions 24 are arranged in an area on the second surface 22 of the light guide plate 2, and more preferably, a plurality of minute protrusions 24 are disposed on the entire surface of the second surface 22, so that the light guide plate 2 and the reflection sheet are arranged. 4 can be effectively prevented in a wide range. In particular, in the non-dot formation region E2 in which the surface state of the second surface 22 is smooth, the second fine protrusions 24B are arranged more densely than the first fine protrusions 24A as described above, whereby the reflective sheet 4 is The sticking phenomenon can be more strongly prevented in the sticking region (E2).

  Conventionally, in order to prevent the light guide plate 2 and the reflection sheet 4 from sticking, it is necessary to secure a wide gap between them. However, as described above, the light guide plate 2 having a plurality of minute protrusions 24 is used. Thus, the gap G between the reflecting sheet 4 and the reflective sheet 4 can be set to the minimum dimension. Therefore, it is possible to reduce the thickness of the backlight unit. Furthermore, since the double-sided tape or the like is not used, the product cost of the backlight unit is not increased. In addition, even when the light guide plate 2 is made of a highly hygroscopic resin, it is possible to prevent sticking to the reflection sheet 4. Therefore, an acrylic resin is used as a constituent material of the light guide plate 2 to provide optical characteristics (light transmittance, etc.). Can be increased.

  Note that the dimensions of the minute protrusions 24 are arbitrary for each product because, when an image is actually displayed on the liquid crystal panel, if the portion provided with the minute protrusions 24 is not recognized as a white spot or the like, there is no problem in the product. Can be set. This also applies to the arrangement of the minute protrusions 24. It is also possible to provide a mixture of microprojections having various shapes and dimensions on the second surface 22 of the light guide plate 2.

  In addition, examples of the shape of the minute protrusion 24 are not limited to the cylindrical shape illustrated in FIG. 4A, but a conical shape illustrated in FIG. 4B, a hemispherical shape illustrated in FIG. Various shapes such as a prismatic shape shown in FIG. 4D and a pyramid shape shown in FIG. 4E can be employed. Furthermore, as another example of the shape of the microprojection 24, an elongated protrusion having a triangular cross section shown in FIG. 5A, an elongated protrusion having a rectangular cross section shown in FIG. 5B, and FIG. It is also possible to adopt a long and slender protrusion having a semicircular cross section. For reference, in FIGS. 4 and 5, the cross-sectional portion of the minute protrusion 24 that is flush with the second surface 22 of the light guide plate 2 is shown by hatching.

  By the way, when the liquid crystal display device is assembled using the backlight unit and the liquid crystal panel unit shown in FIG. 1, the connector insertion portion 6 extends on the back side of the reflection sheet 4 (opposite to the light reflecting direction). In this manner, the FPC 5 is arranged, and the extending portion of the FPC 5 reaching the connector insertion portion 6 is assembled so as to be bent. In such a case, the reflective sheet 4 may be locally pressed by the FPC 5 from the back side while the FPC 5 is bent. Therefore, when the pitch (interval) of the minute projections 24 provided in the dot formation region E1 of the second surface 22 of the light guide plate 2 is wide, the portion where the reflection sheet 4 is pressed by the FPC 5 (particularly in a dot shape). At the pressed portion), sticking to the light guide plate 2 is likely to occur.

  When sticking between the light guide plate 2 and the reflection sheet 4 occurs due to the pressure accompanying the bending of the FPC 5, only that portion locally becomes a bright spot that is brighter than other portions (the light guide plate in the portion where the microprojections 24 are not formed). 2 and the reflective sheet 4 stick together, and the brightness is partially increased). Such a phenomenon may occur even when the reflection sheet 4 is pressed by other parts such as a unit part other than the FPC 5 described above, for example, a case (not shown), during assembly of the liquid crystal display device.

  Since the bright spots generated when the reflective sheet 4 is locally pressed from the back side in this manner (hereinafter referred to as “back-lit bright spots”) are generated in the image display area of the liquid crystal display device, this image display area Preventing the above-mentioned local sticking in the dot formation region E1 of the light guide plate 22 corresponding to is an effective solution for the generation of back-lit bright spots. Incidentally, the dot formation area E1 is a slightly larger area than the image display area.

  In another embodiment of the present invention, the arrangement pitch of the first microprotrusions 24A is set as follows in the entire area of the dot formation area E1 of the second surface 22 of the light guide plate 2. That is, as shown in FIG. 6, when regularly arranging a plurality (a large number) of microprojections 24A in the dot formation region E1, the arrangement pitches P1 and P2 are approximately equal to 1 to 2 mm (preferably approximately 1 mm). It was decided to set (P1 = P2). The arrangement pitch P1 is an arrangement pitch in a direction parallel to one side of the light guide plate 22 (vertical direction in FIG. 6), and the arrangement pitch p2 is a direction parallel to the other side of the light guide plate 22 perpendicular to the one side (in FIG. 6). (Horizontal direction). In this case, the fine protrusion 24A is formed in, for example, a columnar shape or a conical shape, and has an outer diameter (diameter) φD of about 0.1 mm and a height of 0.03 to 0.05 mm.

  By defining the arrangement pitch of the minute projections 24A in this way, a plurality of minute projections 24A are interposed at a narrow pitch between the light guide plate 2 and the reflection sheet 44 (opposed portion), and both (2, 4 ) Is kept constant. Moreover, even when the reflection sheet 4 is pressed from the back side by the FPC 5 or the like, the relative approaching movement (displacement) between the light guide plate 2 and the reflection sheet 4 is formed at a narrow pitch as described above. This is prevented by the contact between the formed microprotrusions 24 and the reflection sheet 4. Therefore, sticking of the light guide plate 2 and the reflection sheet 4 due to pressing from the back side of the sheet and generation of back-pressed bright spots can be surely prevented, and deterioration of display characteristics such as luminance unevenness can be avoided.

  In FIG. 6, the first minute protrusions 24A are arranged at a pitch of about 1 to 2 mm (1 to 2 mm means 1 mm or more and 2 mm or less) in the entire area of the dot formation area E1. For example, when the positional relationship between the reflection sheet 4 and the FPC 5 disposed on the back surface side is known in advance, the arrangement pitch of the microprojections 24 is set to be narrow to about 1 to 2 mm only at the portion pressed by the bending of the FPC 5. May be. That is, as shown in FIG. 7, in the dot formation region E1, in the partial region E3 pressed by the FPC 5, the arrangement pitch of the first microprojections 24A is set within a range of approximately 1 to 2 mm, and the other regions Then, the arrangement pitch of the first minute protrusions 24A is set wider than 2 mm. Thereby, generation | occurrence | production of the back pushing bright spot accompanying the bending of FPC5 can be prevented efficiently. That is, the arrangement pitch of the first micro-projections 24A is changed only in a portion where the reflective sheet 4 may be actually pressed depending on the shape and position of unit parts such as the FPC 5 and the cover disposed on the back surface side of the reflective sheet 4. What is necessary is just to form narrowing. Therefore, it is possible to efficiently prevent the back-lit bright spots without complicating the molding die and reducing the productivity associated therewith.

  Next, specific effects when other embodiments of the present invention are applied will be described. First, FIG. 8 is a diagram showing measurement results of optical characteristics when applied to a 2.5-inch liquid crystal panel backlight unit. In FIG. 8, as a measurement sample, a sample in which no microprojections were formed in the dot formation region E1 (hereinafter, a product without projections) and a microprojection 24 (first microprojections 24A) at a pitch of 2 mm in the dot formation region E1. ) (Hereinafter referred to as a 2 mm pitch product) and a dot formation region E1 formed with minute projections 24 (first minute projections 24A) at a 1 mm pitch (hereinafter referred to as 1 mm pitch product). The result of having measured the optical characteristic of the completed liquid crystal display device is shown. In this measurement result, the luminance, chromaticity coordinates, color temperature, and luminance ratio indicating the optical characteristics are almost the same regardless of the presence or absence of the microprojections 24 and the arrangement pitch. It was confirmed that the optical characteristics were within the measurement error.

  On the other hand, for each measurement sample described above, when the back side of the reflective sheet 4 was locally pressed, it was measured how much pressing force the back luminescent spots were generated. The measurement results as shown in B) were obtained. That is, a total of six pressing points T1 to T6 are set on the back surface side of the reflecting sheet 4 from the light incident side, and a local pressing is applied to the reflecting sheet 4 for each pressing point T1 to T6, so When the pressing force at the time of occurrence was measured, in the case of a product without protrusion, a pressing force of 1.0 N (Newton) was applied to the pressing points T1 to T3, and a pressing force of 1.5 N was applied to the pressing points T4 to T6. When pressure was applied, a backside bright spot was generated. On the other hand, in the case of a 2 mm pitch product, when a pressing force of 1.5N is applied to the pressing points T1 to T3 and when a pressing force of 2.0N is applied to the pressing points T4 to T6, respectively, A push bright spot was generated, and in the case of a 1 mm pitch product, a back push bright spot was generated when a pressure of 3.0 N or more was applied to the press points T1 to T6. As can be seen from this measurement result, when the minute protrusion 24 is present, the pressing force when the back-lit bright spot is generated can be increased as compared with the case without the minute protrusion 24. In particular, when the arrangement pitch of the fine protrusions 24 is 1 mm, it is confirmed that the pressing force when the back pressing luminescent spot is generated can be increased to 3N or more, which is effective.

  FIG. 10 is a diagram comparing luminance unevenness and appearance in the countermeasure against backside bright spots of the present invention. In FIG. 10, (A) is a product without fine protrusions, (B) is a 2 mm pitch product, and (C) is a 1 mm pitch product. The luminance distribution (contour map) in this case is shown. According to FIGS. 10A to 10C, it is found that the luminance unevenness and the appearance hardly change regardless of the presence / absence of the minute protrusions 24 and the arrangement pitch.

  Based on the measurement results as described above (FIGS. 8 to 10), (1) there is no change in luminance due to the presence or absence of microprojections, and (2) backlit bright spots occur when there are microprojections than when there is no microprojection. In particular, when the pitch is 1 mm and narrow, it is difficult to generate back-lit bright spots. (3) There is no unevenness of brightness due to the presence or absence of minute protrusions or the arrangement pitch. It was also confirmed that the same can be said on the liquid crystal panel. Further, it was confirmed that the light guide plate 2 having the minute projections 24 having a pitch of 1 mm is most effective as a countermeasure against the back-lit bright spot.

  Here, the dimensions of the microprotrusions 24 are illustrated assuming a panel size of 2.5 inches, but the size and arrangement pitch of the microprotrusions 24 formed for the purpose of preventing displacement due to pressing of the reflective sheet 4. Is determined regardless of the panel size. As a matter of course, the arrangement pitch of the minute protrusions 24 can be appropriately changed according to the size of the pressing member (FPC 5, cover, etc.) that presses the reflection sheet 4 from the back surface side.

It is a disassembled perspective view which shows the structural example of the backlight unit used for the liquid crystal display device which concerns on embodiment of this invention. It is a figure which shows the structure of the light-guide plate employ | adopted with the backlight unit which concerns on embodiment of this invention. It is a figure which shows the arrangement | positioning state of a light-guide plate and a reflective sheet. It is a figure which shows the example of a shape of a microprotrusion. It is a figure which shows the other example of a shape of a microprotrusion. It is FIG. (1) which shows the structure of the light-guide plate employ | adopted with the backlight unit which concerns on other embodiment of this invention. It is FIG. (2) which shows the structure of the light-guide plate employ | adopted with the backlight unit which concerns on other embodiment of this invention. It is a figure which shows the measurement result of an optical characteristic. It is a figure which shows the result of having measured the sheet | seat pressing force at the time of back pressing luminescent spot generation | occurrence | production. It is the figure which compared the brightness nonuniformity and appearance by the presence or absence of a microprotrusion, and the difference in arrangement pitch.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... White LED, 2 ... Light guide plate, 3 ... Optical sheet, 4 ... Reflective sheet, 5 ... Flexible printed wiring board (FPC), 21 ... 1st surface, 22 ... 2nd surface, 24 (24A.24B) ... Minute Protrusion

Claims (2)

A light guide plate that guides light incident from the light source and emits the light from the first surface;
A reflective sheet disposed in close proximity to and opposite to the second surface opposite to the first surface of the light guide plate;
On the second surface of the light guide plate, a plurality of minute protrusions for preventing the light guide plate and the reflection sheet from sticking ,
Before Kishirubekoban includes a dot formation area a large number of dots are formed, and a non-dot-forming region where the dots are not formed,
The plurality of microprotrusions include a first microprotrusion disposed in the dot formation region and a second microprotrusion formed in the non-dot formation region, and the second microprotrusion is A backlight unit arranged more densely than the first minute protrusions . A light guide plate that guides light incident from the light source and emits the light from the first surface;
A reflective sheet disposed in close proximity to and opposite to the second surface opposite to the first surface of the light guide plate;
Providing a plurality of minute protrusions on the second surface of the light guide plate ,
The light guide plate has a dot formation region where a large number of dots are formed, and a non-dot formation region where the dots are not formed,
The plurality of microprotrusions include a first microprotrusion disposed in the dot formation region and a second microprotrusion formed in the non-dot formation region, and the second microprotrusion is A liquid crystal display device using a backlight unit arranged more densely than the first minute protrusions .

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