WO2005124228A1

WO2005124228A1 - Light guide plate, method of manufacturing the same, back light, and liquid crystal display device

Info

Publication number: WO2005124228A1
Application number: PCT/JP2005/011882
Authority: WO
Inventors: Masao Yamamoto
Original assignee: Scalar Corporation
Priority date: 2004-06-22
Filing date: 2005-06-22
Publication date: 2005-12-29
Also published as: JP2007273090A

Abstract

A light guide plate, a method of manufacturing the light guide plate, a back light, and a liquid crystal display device. The light guide plate (210) easily manufacturable at low cost is formed by combining a first small compartment (211) with a second small compartment (212) formed in a plate-like right-angled triangular shape in side view. The first small compartment (211) is formed of a transparent material. The second small compartment (212) is formed by adding scattered particles to a transparent material, and formed integrally with the first small compartment (211). A light source (220) faces the surface of the light guide plate (210) to which only the first small compartment (211) is exposed. A light coming from the light source (220) advances from the first small compartment (211) to the second small compartment (212), is scattered by the scattered particles, and then is discharged from a discharge surface (an upper surface in Fig. 2).

Description

Light guide plate, manufacturing method of light guide plate, backlight, liquid crystal display

The present invention relates to a light guide plate mainly used for a backlight of a liquid crystal display device. Background of the Invention

Liquid crystal display devices have become very popular.

The liquid crystal display device includes a liquid crystal panel for displaying an image, and the image displayed on the liquid crystal panel is put on light from behind to be seen by human eyes. However, since the liquid crystal panel itself in the liquid crystal display device does not have a function of emitting light, a mechanism is required to guide the light to the liquid crystal panel from behind to display an image to human eyes.

There are various mechanisms for guiding light from behind to a liquid crystal panel in a liquid crystal display device. For example, there has been known a reflection type liquid crystal display device having a mechanism for reflecting light taken in from the outside behind a liquid crystal panel and guiding the light to the liquid crystal panel. On the other hand, in almost all liquid crystal display devices other than the reflection type liquid crystal display device (for example, a transmissive liquid crystal display device or a transflective liquid crystal display device), a backlight is used. The backlight is a planar light source that emits light spontaneously and is arranged behind the liquid crystal panel. By guiding the light from the backlight to the LCD panel, the image displayed on the LCD panel becomes visible to human eyes.

Backlights are a very important component of LCDs, which have a significant effect on the thickness and power consumption of LCDs. For this reason, a wide variety of backlight technologies have been proposed and put into practical use.

A common type of backlight uses a light guide plate.

The light guide plate is formed of a transparent material in the form of a plate, and emits light introduced into the inside from a light source facing the end face from the emission face which is one of the wide faces. . A typical light guide plate has a projection on its emission surface or a surface opposite to the emission surface. A sharp wave shape with a rhythm function is provided, and the light introduced into the interior from the light source is changed by changing the direction of the light introduced into the interior of the light source from the light source. From the emission surface.

By the way, the above-mentioned corrugated portion is manufactured by processing that requires a very high accuracy with an allowable error of several / m level. Therefore, the production of light guide plates, which are mostly made of resin products, requires very high technology, due to the inherent sink marks of resin products. In fact, the technology required to perform very precise processing is required, so that only a limited number of people can manufacture molds for manufacturing light guide plates, and molds for manufacturing light guide plates. It costs hundreds of millions of dollars to produce a

All of these costs translate into the cost of light guide plates. Therefore, the light guide plate is an expensive component. Such a situation hinders a reduction in the price of a backlight using a light guide plate and a liquid crystal display device using the backlight.

However, a light guide plate having no wave shape as described above has also been proposed. However, such a light guide plate still requires very precise processing. Therefore, the light guide plate is generally difficult to manufacture because it requires precise processing, and is very expensive.

An object of the present invention is to provide a technique for enabling a light guide plate generally used for a backlight of a liquid crystal display device to be manufactured at low cost without using precise processing. Disclosure of the invention

The present invention for solving the above-mentioned problems is as follows.

The light guide plate according to the present invention is formed by forming a transparent material into a plate shape, and emits light introduced into the inside from a light source facing the end face from its emission face. Further, scattering particles capable of scattering light are diffused inside the transparent material, and light introduced into the inside from the light source is scattered by the scattering particles and emitted from the emission surface. It has become.

As described above, the light guide plate according to the present invention is provided with light from the light source introduced inside the light guide plate. In order to change the direction of the light so that the light is emitted from the emission surface, instead of using a wavy shape having the function of a prism on the emission surface of the light guide plate, scattering particles distributed inside the light guide plate Is used. Therefore, the light guide plate of the present invention does not require a corrugated shape that requires precision machining, and therefore does not require precise machining that is necessary for forming a corrugated shape. Therefore, the light guide plate according to the present invention is inexpensive because it is free from the problem of price increase caused by precision processing. In the present invention, the “emitting surface” is any one or two of the two widened surfaces of the plate-shaped light guide plate, and means a surface from which light is emitted. If there are two emission surfaces, the light guide plate of the present invention can be used for a double-sided liquid crystal display device. '

The light source used in combination with the light guide plate in the present invention can be appropriately selected as needed. For example, as the light source, an LED or other point light source can be used, or a small fluorescent lamp or other linear light source can be used. Further, the number of light sources may be singular or plural. If the light guide plate is rectangular, the light source will generally face at least one of the sides when the light guide plate is viewed perpendicular to the emission surface, but in this case there are two or more light sources. It may be a shape that straddles the side of.

Further, in the present invention, the light introduced into the inside from the light source is scattered by the scattering particles and emitted from the emission surface. This is because the light scattered by the scattering particles is directly emitted from the emission surface. It includes both the case where the light is emitted and the case where the light scattered by the scattering particles is reflected from a surface other than the emission surface, such as the bottom surface, and then emitted from the emission surface. The scattering particles to be diffused into the light guide plate according to the present invention are not particularly limited as long as they can scatter light from a light source introduced into the light guide plate. “Scattering” as referred to in the present specification includes both a case where light is reflected and a case where light is refracted. The scattering particles may be those that generate at least one of reflection and refraction of light. The scattering particles can be opaque, for example, a metal powder. In addition, a transparent material such as silicon powder or acrylic powder can be used. If the scattering particles are transparent, not only light reflection but also refraction will occur. Further, the diameter of the scattering particles can be about 2 m to 12 m. visible light In order to scatter the particles, the diameter of the scattering particles is preferably this degree.

The shape of the scattering particles may be any shape. For example, it may be spherical. A plurality of types of scattering particles may be mixed. Materials of different materials, of different sizes, of different shapes, etc., can be arbitrarily mixed and used.

Any method can be used to diffuse the scattering particles into the light guide plate. ^ The scattering particles are mixed with a transparent material used for injection molding, extrusion molding, etc., and molded using the transparent material. By doing so, scattering particles can be diffused inside the light guide plate.

Further, the scattering particles may be uniformly diffused throughout the light guide plate. On the other hand, the scattering particles may have a different density for each part of the light guide plate.

When the density of the scattering particles is changed in each part of the light guide plate, and if the change is appropriate, at least in theory, the intensity of the light emitted from the light guide plate is changed to all parts of the emission surface of the light guide plate. Can be adjusted to be uniform. 'Any transparent material can be used as long as it can be made into a plate shape and has sufficient transparency (at least has translucency) to allow light to enter inside. Can be, for example, a transparent resin. The transparent resin can be, for example, PMMA (acrylic), PC (polycarbonate), COP (cycloolefin polymer).

For example, the number of the scattering particles is set such that the number per unit area when the light guide plate is viewed perpendicular to the emission surface increases in a place where the intensity of the light introduced from the light source becomes weaker. be able to. If the number of scattering particles per unit area when the light guide plate is viewed perpendicular to the emission surface is increased in a place where the intensity of light reaching from the light source becomes weaker, the light is theoretically emitted from the light guide plate Light intensity can be adjusted to be uniform at all parts of the light emitting surface of the light guide plate.

In changing the number of scattered particles per unit area when the light guide plate is viewed perpendicular to the emission surface, for example, the number of scattered particles can be made to continuously change from place to place. For example, the technology for making gradient refractive lenses It could be applied to this. Further, when changing the number of scattering particles per unit area when the light guide plate is viewed perpendicular to the emission surface, this may be realized by dividing the light guide plate into a plurality of small sections. . In this case, the density of the scattering particles in all of the plurality of small sections may be constant, and the density of the scattering particles in each of the plurality of small sections may be different from each other. In this way, the manufacture of the sub-compartments is simpler and it is not difficult to combine them, so that the production of the sub-compartments is less than for a light guide plate in which the number of scattering particles varies continuously from place to place. It is simple and therefore contributes to reducing the manufacturing cost of the light guide plate.

The plurality of small sections in the light guide plate may divide the light guide plate in any manner. For example, the small sections may be arranged in order from the side closer to the part where the light source is expected to be exposed (the order of manufacture may be any). In this case, a smaller section closer to the light source may have a smaller density of the scattering particles in the smaller section. In addition, among the plurality of small sections in the light guide plate, a part including a part where the light source is expected to be exposed may not include the scattering particles.

A guide in which the tongue L particles are arranged such that the number per unit area when the light guide plate is viewed perpendicularly to the emission surface increases as the intensity of light introduced from the light source decreases. Examples of the light plate include the following. That is, a first small section formed of a transparent material and containing no scattering particles, a second small section formed of a transparent material and containing small numbers of scattering particles, and And at least a part thereof, in a state where there is an overlapping portion when viewed from a direction perpendicular to the emission surface. The thickness of the second sub-section is increased as the intensity of the light introduced from the light source decreases, as the intensity of the received light decreases. Light guide plate. The density of the scattered particles in the second small section can be the same in any part of the second small section.

Also, the scattering particles are located at a predetermined position where the light source is expected to be exposed. In a place where the distance from the light guide plate is larger than in a place where the distance is smaller, the number of light guide plates per unit area when viewed perpendicular to the emission surface is not reduced. be able to. For example, as the scattering particles are farther from a predetermined position where the light source is expected to face, the number per unit area when the light guide plate is viewed perpendicular to the emission surface is increased. It can be. This is also useful for adjusting the intensity of light emitted from the light guide plate so as to be uniform at all portions of the emission surface of the light guide plate.

Examples of such light guide plates include the following.

That is, a first subsection, which is a small section formed of a transparent material and does not include scattering particles, and a second subsection, which is a small section formed of a transparent material and includes scattering particles at a predetermined density. At least a part of them is combined in such a state that there is an overlapping part when viewed from a direction perpendicular to the emission surface, and the first light section faces the light source. In a place where the distance from the predetermined position where the event is scheduled is larger, the thickness thereof is prevented from increasing compared to a place where the distance is smaller, and the second sub-partition is It is a light guide plate whose thickness is not reduced at places where the distance from the predetermined position where the light source is expected to be exposed is larger than at places where the distance is smaller than that. .

In this case, the thickness of the first small section decreases as the distance from the predetermined position where the light source is expected to be exposed is increased (however, there may be a portion where the thickness does not change in a part thereof). And the thickness of the second sub-section increases as the distance from the predetermined position where the light source is expected to be seen is increased (however, a portion of the second sub-section where the thickness does not change). May be provided). The density of the scattering particles in the second small section can be the same in any part of the second small section.

The light guide plate according to the present invention may have any shape as long as it has a plate shape. The light guide plate may have a partially changed thickness.

If the light guide plate is rectangular, the light source can face one or more sides of the rectangle. When the light guide plate is rectangular and the light source is expected to face one side thereof, the scattering particles may face the light source. The number of light guide plates per unit area when viewed perpendicular to the emission surface does not decrease in places where the distance from the one side is larger than in places where the distance is smaller. You can do so. For example, the number of the scattering particles increases per unit area when the light guide plate is viewed perpendicular to the emission surface, as the distance from the one side where the light source is expected to face is longer. It can be. This is also useful for adjusting the intensity of light emitted from the light guide plate so as to be uniform at all portions of the emission surface of the light guide plate. In particular, when the light source facing the one side is a linear light source (preferably having a length along the side), the intensity of light emitted from the light guide plate can be reduced even with such a simple configuration. It can be made almost uniform in all parts of the emission surface.

Examples of the light guide plate in this case include the following.

That is, a first subsection, which is a small section formed of a transparent material and does not include scattering particles, and a first subsection, which is formed of a transparent material and includes scattering particles at a predetermined density.

And two sub-compartments are combined in such a state that at least a part thereof overlaps when viewed from a direction perpendicular to the emission surface, and the first sub-compartment is At a place where the distance from a predetermined position where the light source is expected to be exposed is larger, the thickness is not increased as compared with a place where the great distance is smaller, and The thickness of the second subsection is such that its thickness does not decrease at a place where the distance from a predetermined position where the light source is expected to be exposed is larger than at a place where the distance is smaller than that of the predetermined position. This is a light guide plate made in accordance with the present invention. In this case, the thickness of the first small section decreases as the distance from the one side where the light source is expected to face is increased (however, there may be a part where the thickness does not change). In addition, the thickness of the second subsection increases as the distance from the side where the light source is expected to face is increased (however, there may be a portion where the thickness does not change). It may be done. Note that the density of the scattering particles in the second subsection can be the same in any part of the second subsection.

When the light guide plate is rectangular, the light source can face two predetermined sides of the rectangle. When the light guide plate is rectangular and the light source is expected to face two opposite sides thereof, the light source faces the scattering particles. Where the distance from the closer one of the two sides is larger, the light guide plate is viewed perpendicular to the emission surface compared to a smaller distance. In this case, the number per unit area can be prevented from decreasing. This is also useful for adjusting the intensity of light emitted from the light guide plate so as to be uniform at all portions of the light emitting surface of the light guide plate. In particular, when the light source facing the above two sides is a linear light source (preferably of a length along the sides), even with such a simple configuration, the intensity of the light emitted from the light guide plate can be reduced. It can be made almost uniform in all parts of the emission surface of the light guide plate.

Examples of the light guide plate in this case include the following.

And two sub-compartments are combined in such a state that at least a part thereof overlaps when viewed from a direction perpendicular to the emission surface, and the first sub-compartment is At locations where the distance from the closer of the two sides where the light source is supposed to be exposed is greater, its thickness does not increase compared to locations where the distance is smaller. And wherein the second sub-section is located at a greater distance from a closer one of the two sides on which the light source is to be aimed, and at a smaller distance therefrom. It is a light guide plate whose thickness is not reduced by comparison.

In this case, the thickness of the first subsection decreases as the distance from the closer one of the two sides where the light source is expected to face is increased (however, the thickness does not change in a part thereof). And the second sub-section has a thickness that increases with distance from a closer one of the two sides on which the light source is to be seen (however, (There may be a part where the thickness does not change in the part.) For example, the first sub-compartment has its second sub-compartment so that its thickness is maximum at the two sides where the light source is to be exposed, and its thickness is the minimum at the center of the two sides. It can be reversed. In addition, the density of the scattering particles in the second small section can be the same even in the portion of the second small section that is misaligned. If the light guide plate is rectangular, the light source must be able to face all sides (four sides) of the rectangle. You can. In the case where the light guide plate is rectangular and the light source is expected to face all sides thereof, the scattering particles may be formed by diagonally dividing the rectangle of the light guide plate into four areas. In a place where the distance from the side at the end of the range is larger, a unit area when the light guide plate is viewed perpendicular to the emission surface is compared with a place where the distance is smaller. The number of hits can be kept from decreasing. This is also useful for adjusting the intensity of light emitted from the light guide plate so as to be uniform at all portions of the emission surface of the light guide plate. In particular, when the light source facing all of the above sides is a linear light source (preferably of a length along the side), the intensity of the light emitted from the light guide plate even with such a simple configuration. Can be made almost uniform at all parts of the emission surface of the light guide plate.

Examples of the light guide plate in this case include the following.

And two sub-compartments are combined in such a state that at least a part thereof overlaps when viewed from a direction perpendicular to the emission surface, and the first sub-compartment is In each area where the rectangle in the light guide plate is divided into four sections by a diagonal line, a place where the distance from the side at the end of the range is larger than a place where the distance is smaller than the place where the distance is smaller. The thickness of the second sub-section is prevented from increasing, and the thickness of the second sub-section is larger at a location where the distance from the side at the end of the range is larger than at a location where the distance is smaller. It is a light guide plate that is not reduced. In this case, in each range where the rectangle in the light guide plate is divided into four by a diagonal line, the thickness of the first subsection decreases as the distance from the side at the end of the range decreases (however, part of the first subsection decreases). There may be a portion where the thickness does not change), and the thickness of the second subsection increases as the distance from the side at the end of the range increases (however, the thickness does not change in a part thereof). (There may be parts). For example, in each of the four sections of the rectangle on the light guide plate divided by a diagonal line, the first subsection has the maximum thickness on each side and the minimum thickness at the center of each side. The second subdivision can be reversed. Note that the density of the scattering particles in the second subsection can be the same in any part of the second subsection. Light from the light source may be introduced into the light guide plate from the first small section. This makes it easier to send the light from the light source far into the light guide plate while reducing loss.

Note that it may be difficult in practice to introduce all of the light from the light source into the light guide plate from the first subsection.In the present case, the light entering the light guide plate from the first subsection enters the light guide plate. If the input light exceeds 80%, it can be considered that light from the light source is guided from the first subsection to the light guide plate.

Further, the refractive index of the transparent material may be the same in all the portions, or may be different for each portion of the light guide plate. The refractive index of the transparent material serving as the basis of the light guide plate may be changed depending on the position of the light guide plate so as to bend the light from the light source in a direction approaching the emission surface. If this is the case, the amount of light emitted from the emitting surface can be increased, thus helping to maintain the brightness as a planar light source.

In the case where the refractive index of the transparent material is changed depending on the portion, the distribution of the refractive index can be continuously changed like a distributed refractive index type lens.

Further, as described above, the light guide plate may be divided into a plurality of small sections, and the plurality of small sections are arranged in order from a side closer to a portion where the light source is expected to face. It may be. In this case, it is possible to make the refractive index of the transparent material forming each of the small sections smaller as the closer to the light source. In this way, the amount of light emitted from the emitting surface can be increased without increasing the manufacturing difficulty. In addition, light from the light source enters small sections far from the light source in order from small sections near the light source. At this time, when the light is incident from a material having a small refractive index to a material having a large refractive index, total reflection hardly occurs. Therefore, the above-described configuration is suitable for transmitting light to a section far from the light source.

In addition, each of the end faces of the plurality of small sections that are in contact with the adjacent small sections is provided with light coming into the next small section from one of the small sections to a portion where the light source is expected to be exposed. However, the traveling direction may be changed so as to be refracted and approach the emission surface. This is also suitable for increasing the amount of light emitted from the emitting surface It is.

As described above, the light guide plate of the present invention may have the first small section and the second small section in some cases. In such a case, the refractive index of the transparent material forming the first small section may be smaller than the refractive index of the transparent material forming the second small section. That is, the refractive index of the transparent material forming the second small section may be higher than the refractive index of the transparent material forming the first small section.

The light guide plate having the small sections described above can be formed by a multicolor molding method in which one of the small sections is formed, and then the adjacent small sections are formed one after another. That is, such a light guide plate can be manufactured by molding each of the small sections by a multicolor molding method. The multicolor molding method is a technology used when manufacturing a resin product in which a plurality of parts molded with resins of different colors are integrated, and various know-how is accumulated in the resin molding technology. It is an established technology.

Therefore, if the light guide plate is regarded as the above-described resin product and each of the small sections is regarded as a plurality of portions formed of the above-described resins of different colors, the light guide plate having the small sections can be manufactured by using the multicolor molding method. Less difficulties. This also contributes to making the light guide plate at low cost.

The light guide plate according to the present invention can be used as a backlight by making the light source face the end. Further, such a backlight can be applied to a backlight of a liquid crystal display device. Brief Description of Drawings

FIG. 1 is a perspective view schematically showing the configuration of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a configuration of a backlight of the liquid crystal display device shown in FIG.

3A to 3E are side views showing modifications of the light guide plate included in the backlight shown in FIG.

4A to 4E show another modification of the light guide plate included in the backlight shown in FIG. FIG.

FIG. 5 is a perspective view showing still another modification of the light guide plate included in the backlight shown in FIG.

FIG. 6 is a plan view showing still another modification of the light guide plate included in the backlight shown in FIG.

7A and 7B are side views showing modified examples of the light guide plate included in the backlight shown in FIG.

FIG. 8 is a perspective view schematically showing a configuration of a backlight included in the liquid crystal display device according to the second embodiment.

FIG. 9 is a perspective view schematically showing a configuration of a backlight included in the liquid crystal display device according to the third embodiment.

FIG. 10 is a perspective view schematically showing a configuration of a backlight included in the liquid crystal display device according to the fourth embodiment.

FIG. 11 is a view for explaining a modification of the light guide plate included in the liquid crystal display device according to the fourth embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred first to fourth embodiments of the present invention will be described with reference to the drawings. In the first to fourth embodiments, the same reference numerals are given to the overlapping portions, and the overlapping description is omitted.

Each of the first to fourth embodiments relates to a liquid crystal display device including a backlight including the light guide plate according to the present invention.

<< 1st Embodiment >>

The liquid crystal display device according to the first embodiment has a configuration schematically shown in FIG.

This liquid crystal display device is configured by combining a liquid crystal panel 100 and a backlight 200. The backlight 200 is arranged on the back side of the liquid crystal panel 100, that is, on the side far from the eyes of a viewer of the liquid crystal display device.

This liquid crystal display transmits light from the backlight 200 to the liquid crystal panel 100. By doing so, the user can see a predetermined image. The liquid crystal display device includes a case for accommodating the liquid crystal panel 100 and the backlight 200, a circuit board for controlling the driving of the liquid crystal panel 100, and the like. The description and illustration are omitted.

As the liquid crystal panel 100, any existing liquid crystal panel may be used, but in this embodiment, the structure is as shown in FIG. The liquid crystal panel 100 has a liquid crystal layer 110 in the middle. The liquid crystal layer 110 is sandwiched between the alignment film layers 120. A transparent electrode layer 130 is provided outside the both alignment film layers 120. A glass substrate 140 is provided outside the transparent electrode layers 130, and a polarizing plate 150 is provided outside the glass substrates 140. Note that a color filter layer is provided between the front side of the liquid crystal panel 100, that is, the transparent electrode layer 130 nearer to the viewer's eyes and the glass substrate 140. 160 is provided.

In this embodiment, the liquid crystal layer 110, the alignment film layer 120, the transparent electrode layer 130, the glass substrate 140, the polarizing plate 150, and the color filter layer 160 are all the same. , More specifically the same rectangular shape.

The above-mentioned liquid crystal layer 110, alignment film layer 120, transparent electrode layer 130, glass substrate 140, polarizing plate 150, and color filter layer 160 are as follows. is there.

Both polarizing plates 150 have a function of converting natural light transmitted therethrough into linearly polarized light in a predetermined direction. Of the polarizing plates 150 in this embodiment, the one on the back side has a role of polarizing the light emitted from the Socrite 200. On the other hand, among the polarizing plates 150, the front one is polarized after passing through the rear polarizing plate 150, and then passes through the liquid crystal layer 110, and the polarization plane is rotated as necessary. It has the role of passing or blocking the light. The liquid crystal layer 110 is driven as necessary, and the light polarized by passing through the rear polarizing plate 150 is maintained in the same polarization state or rotated 90 °. Let through. It is the transparent electrode layer 130 that controls the driving of the liquid crystal layer 110 performed to rotate the polarization plane, and the transparent electrode layer 130 is driven by a change in the potential difference therebetween. 10 control is realized.

The alignment film layer 120 sandwiches the liquid crystal layer 110, and the liquid crystal in the liquid crystal layer 110 It has the function of regulating the orientation direction.

The glass substrate 140 sandwiches a liquid crystal layer 110, an alignment film layer 120, a transparent electrode layer 130, and a color filter layer 160 therebetween.

The color fill layer 160 is a layer formed by a color fill layer for coloring light passing through it. The color filter layer 160 is generally composed of fine filters of R (red), G (green), and B (blue) arranged in a matrix, and in this embodiment, it is so. .

On the other hand, Nosocrite 200 is configured as shown in FIG.

The backlight 200 in this embodiment includes a light guide plate 210 and a light source 220. The light guide plate 210 combines the first small section 2 11 in which the scattering particles are not diffused and the second small section 2 12 in which the scattering particles are diffused, thereby forming a concave portion 20 OA described later. Except for it, it is formed to be a rectangular parallelepiped. That is, the light guide plate 210 has a rectangular shape when viewed from a direction perpendicular to its wide surface, and is formed in a thin plate shape. The emission surface in this embodiment, that is, the surface from which the light introduced from the light source 220 into the light guide plate 210 is emitted is the upper surface of the light guide plate 210 in FIG.

The first small section 2 1 1 is formed of a transparent resin, for example, PMMA, PC, COP (in this embodiment, PMMA). In this embodiment, the second subsection 211 is made of transparent resin (which may be the same as or different from the first subsection 211) plus scattering particles, for example, silicon or acrylic particles. It is formed. The scattering particles in this embodiment are spheres, and their diameters are 7 m and 3 m in this embodiment. That is, in this embodiment, two types of scattering particles having different sizes are used. The color temperature of the light emitted from the emitting surface can be adjusted by the size of the scattering particles. In this embodiment, the color temperature of light emitted from the emission surface is adjusted by using the scattering particles having the two diameters described above.

In this embodiment, the refractive index of the transparent material forming the first small section 2 11 is smaller than (at least the same as) the refractive index of the transparent material forming the second small section 2 12. In this embodiment, the refractive index of the first small section 2 11 is 1.49, and the refractive index of the second small section 2 12 is 1.55. In this embodiment, the scattering particles in the second small section 2 12 are uniformly diffused throughout the second small section 2 12. The first small section 2 1 1 and the second small section 2 1 2 have the same right-angled triangular shape when viewed from the side, and their hypotenuse portions are in contact with each other. . Therefore, the thickness of the light guide plate 210 is the same in any part.

The first small section 2 1 1 and the second small section 2 1 2 are integrally formed by a multi-color (here, two-color) molding method. Since the two-color molding method is a well-known method, a detailed description thereof will be omitted. For example, as described below, the light guide plate 2 10 having the first small section 2 1 1 and the second small section 2 1 2 Can be manufactured. Such a manufacturing method is based on the following. First, the raw materials of the first sub-compartment 211 and the second sub-compartment 212 in liquid or gel state (in this embodiment, the raw material of the first sub-compartment 211 is liquid) PMM A tree Ji, the raw material of the second sub-compartment 2 1 2 is a mixture of liquid PMMA resin and scattering particles.) 1. One of the second sub-compartments 2 1 2 is formed first, and then the other sub-compartments, with the above-mentioned oblique sides of the first sub-compartments 2 1 1 and 2 1 2 being part of the mold. That is, the other of the raw materials of the first small section 2 11 or the second small section 2 12 is injected.

The light guide plate 210 is located at the center of the portion corresponding to one side of the above-described rectangle, more specifically, at the center portion of the end face where only the first small section 211 is exposed, and the light source 220 is located at the center. It has a recess 20 OA that is a hole with a circular cross section that fits inside. The concave portion 200A may be formed by using a mold when the first small section 2 11 and the second small section 2 12 are manufactured by a two-color molding method. The first small section 2 1 1 and the second small section 2 1 2 may be formed into a rectangular parallelepiped shape, and then the first small section 2 11 1 may be cut.

Further, the light guide plate 210 according to this embodiment is not necessarily required to have such a shape. However, the end surface (side surface) excluding the inside of the concave portion OA and the bottom surface are formed from the inside of the light guide plate 210. The light guide plate 210 is provided with a reflector that reflects light that is going to go outside. The reflector can be manufactured, for example, by arranging a mirror-like member different from the light guide plate 210 around the light guide plate 210, or by using aluminum or the like in a necessary portion of the light guide plate 210. It can also be manufactured by vapor-depositing a metal. The light source 220 is a point light source in this embodiment. The light source 220 in this embodiment is an LED. The light source 220 is controlled to be turned on as necessary. Although the number of the light sources 220 in this embodiment is one, a plurality of the light sources 220 may be arranged at predetermined intervals on the side.

In this embodiment, the light source 220 faces the inside of the above-mentioned concave portion 20OA provided in the light guide plate 210. The light from the light source 220 is introduced into the light guide plate 210 from the inner surface of the concave portion 20OA.

Since the light guide plate 210 according to this embodiment is as described above, the thickness of the first subsection 2 11 decreases as the distance from one side of the rectangular shape facing the light source 220 decreases. The thickness of the second subsection 2 1 2 is increased. Since the first small section 2 11 1 does not contain scattered particles and the second small section 2 12 contains scattered particles at a certain density, the light guide plate 2 10 The longer the distance from the above one side of the rectangular shape facing 20, the greater the number of scattering particles per unit area when the light guide plate 210 is viewed perpendicular to the emission surface. ing.

When light is introduced from the light source 220 into the light guide plate 210 according to this embodiment, the light travels through the light guide plate 210 and scatters on the scattering particles contained in the light guide plate 210. The scattered light is emitted to the outside from the emission surface of the light guide plate 210 directly or after being reflected by a reflector. Thus, the backlight 200 including the light guide plate 210 and the light source 220 functions as a planar light source.

Since the light source 220 in the first embodiment is a point light source, if a concentric circle centered on the light source 220 is considered, the light source 220 reaching the concentric circle becomes larger as the size of the concentric circle becomes larger. Light is reduced. In other words, the light guide plate 210 is formed such that as the distance from the above one side of the light guide plate 210 facing the light source 220 increases, the unit area of the scattered particles when viewed perpendicular to the emission surface increases. More specifically, more specifically, the number of scattering particles per unit area when viewed perpendicular to the emission surface increases in proportion to the distance from the one side of the light guide plate 210. . When the light guide plate 210 is not configured as described above, the light reaching from the light source 220 to a portion far from the above one side of the light guide plate 210 facing the light source 220 is close to the above one side. Since the amount of light is smaller than that of the part, even if light scattering by scattering particles The light emitted from the emission surface may be weakened as the distance from the one side of the light guide plate 210 facing the light source 220 increases. . Here, as in the case of the light guide plate 210 in the present embodiment, the number of scattering particles per unit area when viewed perpendicular to the emission surface increases in proportion to the distance from the above one side. If so, the weakness of the light scattered by the scattering particles can be compensated for by the number of scattering particles per unit area (that is, the number of times of light scattering), so that the light emitted from the emission surface of the light guide plate 210 Amount becomes nearly uniform across the emission surface. This means that the backlight 200 as a planar light source can emit light that is nearly uniform over its entire surface, and is therefore preferable.

Note that, in this embodiment, light that exits from the light source 220 and travels from right to left in FIG. 2 in the light guide plate 210 when entering the second small partition 2 1 2 from the first small partition 2 1 1 Change its direction to get closer to the emission surface. This increases the amount of light exiting the emitting surface in this embodiment.

The light guide plate 210 in the first embodiment can be modified as shown in FIGS. 3A to 3E. 3A to 3E are side views showing a state where the light guide plate 210 is viewed from the same direction as the front direction in FIG. The light guide plates 210 in FIGS. 3A to 3E are all rectangular plates. In addition, all of the light guide plates 210 of FIGS. 3A to 3E have the same vertical cross section except for the concave portion 200A.

The light guide plate 210 of FIG. 3A has a plane parallel to the emission surface in both the first subsection 2 1 1 and the second subsection 2 1 2, so that unlike the first embodiment, the light source As the distance from the side at which 220 is expected to face increases, the thickness of the first subsection 2 11 1 decreases, and as the distance increases, the thickness of the second subsection 2 1 2 increases. It has not become. However, in this modified example, the first small section 2 1 1 is located at a larger distance from one side of the light guide plate 2 10 where the light source 2 2 0 is expected to face. The second sub-compartment 2 1 2 is designed so that the light source 2 2 At places where the distance from the side is larger, the thickness is not reduced compared to places where the distance is smaller. This is illustrated in Figures 3B to 3E. The same applies to the light guide plate 210 thus obtained.

The light guide plate 210 may be as shown in FIG. 3B. In the light guide plate 210 of FIG. 3B, the shape of the first small section 2 11 in a side view is a right triangle, and the shape of the second small section 2 12 in a side view is a trapezoid.

The light guide plate 210 may be as shown in FIG. 3C. In the light guide plate 210 of FIG. 3C, the side view shape of the first small section 211 is trapezoidal, and the side view shape of the second small section 211 is a right triangle.

The light guide plate 210 can be as shown in FIG. 3D. In the light guide plate 210 of FIG. 3D, the line formed by the boundary surface between the first small section 2 11 and the second small section 2 12 is a curve. That is, in this modified example, the boundary surface between the first small section 2 11 and the second small section 2 12 is a curved surface. The curve created by the interface can be, for example, part of a logarithmic curve.

The light guide plate 210 may be as shown in FIG. 3E.

In the light guide plate 210 of FIG. 3E, the line formed by the interface between the first subsection 2 11 and the second subsection 2.12 is curved. This curve touches both the emission surface and the bottom surface. The curve created by the interface can be, for example, part of a logarithmic curve. The light guide plate 210 in the first embodiment can be modified as shown in FIGS. 4A to 4E. 4A to 4E are side views showing a state where the light guide plate 210 is viewed from the same direction as the front direction in FIG. Note that all of the light guide plates 210 in FIGS. 4A to 4E are rectangular plates. In addition, all of the light guide plates 210 of FIGS. 4A to 4E have the same vertical cross section except for the concave portion 200A.

The light guide plate 210 can be as shown in FIG. 4A. The light guide plate 210 of FIG. 4 includes not only the first small section 2 11 and the second small section 2 12 but also the third small section 2 13 and the fourth small section 2 14. The side view shape of the first small section 2 11 is the same as that of the first embodiment. The side view shape of the second small section 2 1 2, the third small section 2 13, and the fourth small section 2 14 is a plurality of straight lines passing through the right vertex through the second small section 2 12 of the first embodiment. And is formed by slicing.

In the light guide plate 210 in this modification, the refractive index of the first subsection 2 11 <the second subsection The refractive index of the third small section 2 13 is larger than the refractive index of the image 2 12, and the refractive index of the fourth small section 2 14 is larger than the refractive index of the third small section 2 13. The first subsection 2 11, the second subsection 2 12, the third subsection 2 13, and the fourth subsection 2 14 all have a high density of scattered particles in any location. Has been made the same. In this embodiment, the density of the scattered particles in the first subsection 2 11 1 is smaller than the density of the scattered particles in the second subsection 2 12 <the fourth subsection 2 is larger than the density of the scattered particles in the third subsection 2 13. It is the density of the scattering particles in 14. In this embodiment, the first subsection 2 11 does not contain scattering particles. In this modification, not only the second subsection 2 12 but also the third subsection 2 13 and the fourth subsection 2 14 contain particles. This can be seen as having a small section containing scattering particles in addition to the second small section 2 1 2, but only dividing the second small section 2 1 2 containing scattering particles into a plurality. You can see it. In other words, the second subsection 2 1 2 in the present invention may be divided into a plurality of sections, and each subsection obtained by dividing the second subsection 2 1 2 into a plurality is divided into other subsections. Either the density or the refractive index of the scattering particles may be different.

The relative relationship between the refractive index and the relative density of the scattered particles in the first subsection 2 11 to the fourth subsection 2 14 (the fourth subsection 2 14 may not exist). Such a relationship is the same as that described above in the modified examples shown in FIGS. 4B to 4E.

The light guide plate 210 may be as shown in FIG. 4B. In the light guide plate 210 of FIG. 4B, the side view shape of the first small section 2 11 is a right-angled triangle similar to the case of the first embodiment. The side view shape of the second small section 2 12 and the third small section 2 13 is a shape formed by diagonally dividing the second small section 2 12 in the first embodiment in the middle. ing.

The light guide plate 210 may be as shown in FIG. 4C. The side view shape of the first small section 211 in the light guide plate 210 of FIG. 4C is a right-angled triangle similar to the case of the first embodiment. The side view shape of the second small section 2 1 2 and the third small section 2 13 is a straight line in which the inclination angle of the emission surface with respect to the back surface is smaller than the inclination angle of the hypotenuse when the first small section 2 11 1 is viewed in side view. Thus, a shape obtained by dividing a portion of the light guide plate 210 other than the first small section 211 is obtained.

The light guide plate 210 can be as shown in FIG. 4D. Figure 4D In the light plate 210, the shapes of the first subsection 2 11 to the fourth subsection 2 14 are all trapezoids in side view. Further, in this embodiment, the inclination of the line formed by the boundary surface that defines the first subsection 2 1 1 and the second subsection 2 1 2 with respect to the back surface> the second subsection 2 1 2 and the third subsection The slope of the line created by the boundary that separates 2 1 3 with respect to the back of the emission surface> The slope of the line created by the boundary that separates 3rd and 4th small sections 2 1 3 and 2 1 4 with respect to the back It has become.

The light guide plate 210 may be as shown in FIG. 4E. In the light guide plate 210 of FIG. 4E, the line formed by the boundary surface between the first subsection 2 1 1 and the second subsection 2 1 2, and the second subsection 2 1 2 and the third subsection 2 1 The line created by the boundary between 3 is a curve. The above-described curve created by the interface can be, for example, part of a logarithmic curve. Note that the light guide plate 210 in the first embodiment can be modified as shown in FIG. FIG. 5 is a perspective view showing the backlight 200.

The light guide plate 210 in this modification includes a first small section 2 11 and a second small section 2 1 2. The first small section 2 11 and the second small section 2 12 of the light guide plate 210 in this modification are the same as those of the first embodiment except for their shapes.

As shown in FIG. 5, the first small section 2 1 1 in this modification has a shape like a half-cut shell-shaped object turned down. The line created by the interface between the first sub-section 2 1 1 and the second sub-section 2 1 2 is cut along the plane passing through A—A to D—D in FIG. In this case, it will be as shown in the lower half of Figure 5. In this variation, the first subdivision 2 11 is located at a greater distance from the location where the light source 220 is expected to be exposed (i.e., the recess 20 OA). The thickness is made smaller than in a small place. Further, the second small section 2 12 is configured such that its thickness is larger at a place where the distance from the recess 20 OA is longer than at a place where the distance is shorter. In addition, the first small section 2 11 and the second small section 2 12 in this modified example consider that the light from the light source 220 that reaches there is weakened if the distance from the light source 220 is large. In this case, the first subsection 2 1 1 is reduced in thickness at a place where the intensity of the light introduced from the light source 2 20 is weakened, and the second subsection 2 1 2 is configured by the light source 2 2 It can be said that the thickness increases as the intensity of light introduced from zero decreases. Although the above is theoretically as described above, when an LED is actually used for the light source 220, the amount of light traveling toward both ends of the side where the light source 220 faces is reduced. The LED emits less light in the side direction than light emitted in the front direction). In consideration of this point, auxiliary light sources as shown in the plan view of FIG. 6 are provided at both ends of the side where the light source 220 faces. Section 2 1 2 A can be provided. Thereby, uniform light can be easily emitted from the entire emission surface of the light guide plate 210. The auxiliary small section 2 12 A has, for example, a triangular prism shape having a cross section shown in the plan view of FIG. 6 and extending from the emission surface to the surface opposite to the emission surface.

The light guide plate 210 in the first embodiment can be modified as shown in FIGS. 7A and 7B. 7A and 7B are side views showing a state where the light guide plate 210 is viewed from the same direction as the front direction in FIG. Each of the light guide plates 210 shown in FIGS. 7A and 7B has the same vertical cross-section everywhere except for the concave portion 20OA.

In FIG. 7A, the light guide plate 210 has gradation. This gradation conceptually shows the density of scattering particles diffused inside the light guide plate 210. The darker the gradation, the higher the density of scattering particles. As can be seen from FIG. 7A, the scattered particles in the light guide plate 210 are closer to the unit area when viewed in a direction perpendicular to the emission surface as the intensity of the light introduced from the light source 220 decreases. Can be said to be increasing.

As described above, when an actual LED is used as a light source, the intensity of emitted light differs depending on the emission direction. A change in the concentration of the scattered particles that compensates for this can be given to the light guide plate 210 described above.

The light guide plate 210 shown in FIG. 7B is also provided with gradation. The gradation in FIG. 7B indicates the refractive index at that portion of the light guide plate 210. The darker the gradation color, the higher the refractive index at that location, and the lighter the gradation color, the lower the refractive index at that location. When such a change in the refractive index is given, the light from the light source 220 bends in a direction approaching the emission surface, so that the amount of light emitted from the emission surface can be increased.

<< 2nd Embodiment >> The liquid crystal display device according to the second embodiment is basically the same as that of the first embodiment.

The liquid crystal display device according to the second embodiment includes a liquid crystal panel 100 and a backlight 200. The liquid crystal panel in the liquid crystal display device of the second embodiment is not different from the liquid crystal panel 100 of the first embodiment.

The liquid crystal display device according to the second embodiment is different from the liquid crystal display device according to the first embodiment in the backlight 200 thereof.

The backlight 200 included in the liquid crystal display device according to the second embodiment is configured as shown in FIG.

As shown in FIG. 8, the light source 220 in the backlight 200 is a linear light source, unlike the light source 220 of the first embodiment which was a point light source. In this embodiment, the light source 220 has a cylindrical shape that is the same as the length of one side of the rectangular shape of the light guide plate 210 on which the light source 220 faces. The light source 220 can be, for example, a small fluorescent lamp, which is the case in this embodiment.

In the second embodiment, the shape of the concave portion 200A is different from that of the concave portion 200A of the first embodiment, because the light source 220 is a linear light source. . As is apparent from FIG. 8, the concave portion 20OA provided in the light guide plate 210 in the second embodiment is a groove having a semicircular cross section. The linear light source 220 described above is inserted into the groove-shaped concave portion 20OA.

In the case where the linear light source 220 as shown in the second embodiment is used, the light inside the light guide plate 210 that can reach the light source 220 is the side where the light source 220 faces. It becomes smaller as the distance from becomes longer. Here, as shown in the first embodiment, the longer the distance from the above one side of the rectangular shape facing the light source 220, the larger the unit area of the scattering particles when viewed perpendicular to the emission surface. The use of the light guide plate 210 with a larger number per unit enables better compensation by the number of times of light scattering described above.

Note that, on the side of the light source 220 according to the second embodiment far from the light guide plate 210, light from the light source 220 that does not face the end face of the light guide plate 210 is guided into the light guide plate 210. A reflecting member 230 having a function is provided. The reflection member 230 is a light guide plate 210 It has a U-shaped cross section provided with a groove for accommodating the protruding light source 220 therein, and the inside of the groove is a mirror surface.

The liquid crystal display device according to the third embodiment is basically the same as that of the first embodiment.

The liquid crystal display device according to the third embodiment includes the same liquid crystal panel 100 as that of the first embodiment, and further includes a backlight 200.

The liquid crystal display device according to the third embodiment is different from the liquid crystal display device according to the first embodiment in a backlight 200 thereof.

The backlight 200 included in the liquid crystal display device according to the third embodiment is configured as shown in FIG.

As shown in FIG. 9, the light source 220 in the backlight 200 is a linear light source similar to that described in the second embodiment. Then, two light sources 220 in the third embodiment are provided on each of two opposite sides of the light guide plate 210 which is rectangular when viewed from a plane perpendicular to the emission surface. ing.

As shown in FIG. 9, the light guide plate 210 in this embodiment includes two first small sections 2 11 and a second small section 2 12. The shape of the first small section 2 1 1 is the same as that of the first embodiment, with the right side in the figure being a right triangle in side view and the same shape as the first embodiment. The first subsection 2 1 1 on the right side is inverted from the center of the side. There is one second small section 2 1, but the second small section 2 12 faces the right side centering on the center of the two sides facing each other similarly to the case of the first embodiment. The portion on the left side with the center of the two sides described above as a center has a shape obtained by inverting the second small section 2 12 on the right side with the center of the two sides facing each other as the center.

That is, the light guide plate 210 in this embodiment has a shape obtained by inverting the light guide plate 210 shown in FIG. 8 at the left end portion and connecting the inverted light guide plate 210 at the left end portion. Has become.

It should be noted that the light guide plate 210 shown in the modification of the first embodiment is inverted at the left end using FIGS. 3A to 3E, 4A to 4E, etc. Connected with It is also possible to use the light guide plate 210 in the shape of a circle as the light guide plate 210 of this embodiment. For example, by inverting the light guide plate 210 in which both the distribution of the scattering particles and the distribution of the refractive index shown in FIG. 7 continuously change at the left end, and connecting it to the original light guide plate 210. The resulting light guide plate 210 can be used as the light guide plate 210 of the present embodiment.

<< 4th Embodiment>

The liquid crystal display device according to the fourth embodiment is basically the same as that of the first embodiment.

The liquid crystal display device according to the fourth embodiment includes the same liquid crystal panel 100 as that of the first embodiment, and further includes a backlight 200.

The liquid crystal display device according to the fourth embodiment is different from the liquid crystal display device according to the first embodiment in a backlight 200 thereof.

The backlight 200 included in the liquid crystal display device according to the fourth embodiment is configured as shown in FIG.

As shown in FIG. 10, the light source 220 in the backlight 200 is a linear light source similar to that described in the second embodiment. In the fourth embodiment, four light sources 220 are provided on each of four sides of the light guide plate 210 which is rectangular when viewed from a plane perpendicular to the emission surface. .

As shown in FIG. 10, the light guide plate 210 in this embodiment includes a first small section 2 11 and a second small section 2 12. In this embodiment, the second small section 2 12 has a quadrangular pyramid shape in which the emission surface is a bottom surface and the surface on the back side of the emission surface is a vertex opposed to the bottom surface. The first small section 2 11 1 has a shape obtained by removing the above-described second small section 2 12 having a square pyramid shape from the light guide plate 2 10.

By the way, first, a light guide plate 210 shown in FIG. 2 is defined as a straight line that is perpendicular to the emission surface and that connects both ends of the side facing the light source 220 and the center of the side facing the side. The part that has an isosceles triangular shape (Fig. 11 (A)) when viewed from the direction perpendicular to the emission surface created by cutting two planes is slightly changed in the ratio of the base to the height. When the four parts are combined (FIG. 11 (B)) and the adjacent parts are connected (FIG. 11 (C)), the light guide plate 210 shown in FIG. 10 is obtained. Thus, Fig. 3A to Fig. 3E, Fig. 4A to Fig. The light guide plate 210 shown in the modified example of the first embodiment using 4E or the like is perpendicular to the emission surface thereof, and faces both ends of the side facing the light source 220 and the side. The light guide plate 210 obtained by combining four parts obtained by cutting out two planes including a straight line connecting the center of the side with a slight change in the ratio of the base to the height is It can be used as the light guide plate 210 of the embodiment.

Claims

The scope of the claims

1. A light guide plate that is formed of a transparent material in a plate shape and emits light introduced into the interior from a light source facing the end face from an emission surface thereof. Inside, scattering particles capable of scattering light are diffused, and light introduced into the inside from the light source is scattered by the scattering particles and emitted from the emission surface,

The transparent material has a refractive index that is changed depending on a position of the transparent material so as to bend the light from the light source toward the emission surface.

Light guide plate.

2. In the place where the intensity of light introduced from the light source becomes weaker, the number of particles per unit area when the light guide plate is viewed perpendicularly to the emission surface is increased in the place where the intensity of light introduced from the light source is reduced. It's been,

The light guide plate according to claim 1.

3. The light guide plate is divided into a plurality of small sections,

All of the plurality of small sections have a constant density of the scattering particles inside thereof, and the density of the scattering particles in each of the plurality of small sections is different from each other.

3. The light guide plate according to claim 1 or 2.

4. The plurality of small sections in the light guide plate are arranged in order from a side closer to a portion where the light source is expected to be exposed, and the closer to the light source, the more the scattering particles in the small section. The density of is reduced,

4. The light guide plate according to claim 3, wherein:

5. The light guide plate according to claim 3, wherein, among the plurality of small sections, a section including a portion where the light source is expected to be exposed is configured not to include the scattering particles. Or the light guide plate according to item 4.

6. a first sub-compartment formed of a transparent material, the sub-compartment not including the scattering particles;

The second section is a small section formed of a transparent material and containing the scattering particles at a predetermined density. 2 small parcels,

And in such a state that at least a part thereof has an overlapping portion when viewed from a direction perpendicular to the emission surface,

The thickness of the first subsection is reduced as the intensity of the light introduced from the light source decreases, and the intensity of the light introduced from the light source is reduced in the second subsection. The more the place, the thicker it is,

3. The light guide plate according to claim 1 or 2.

7. The scattering particles cause the light guide plate to move toward the emission surface at a location where the distance from a predetermined position where the light source is expected to face is larger than at a location where the distance is smaller. The number per unit area when viewed perpendicularly to

The light guide plate according to claim 1.

8. A first sub-section formed of a transparent material and not including the scattering particles,

A second small section formed of a transparent material, the second small section being a small section containing the scattering particles at a predetermined density;

The first sub-section is such that its thickness is not increased at a place where the distance from a predetermined position where the light source is expected to be exposed is larger than that at a place where the distance is smaller than that of the first sub-section. And the second sub-compartment has a thickness at a place where the distance from a predetermined position where the light source is expected to be projected is larger than that at a place where the distance is smaller than the place where the light source is expected to be seen. Is not reduced,

8. The light guide plate according to claim 1 or claim 7.

9. The light guide plate is rectangular, and the light source is expected to face one side thereof,

The scattering particles cause the light guide plate to move away from the emission surface at a place where the distance from the one side where the light source is supposed to face is larger than at a place where the distance is smaller. If the number per unit area when viewed vertically is small Not to be,

The light guide plate according to claim 1.

10. A first subsection formed of a transparent material and not including the scattering particles,

The first subsection is provided so that its thickness is not increased at a place where the distance from the one side where the light source is expected to face is larger than that at a place where the distance is smaller than the one side. And the thickness of the second sub-section does not decrease at a place where the distance from the one side where the light source is expected to face is larger than that at a place where the distance is smaller than the one side. Like that,

10. The light guide plate according to claim 9, wherein:

1 1. The light guide plate is rectangular, and the light source is expected to face two predetermined opposite sides thereof,

The scattering particles may cause the light guide plate to be located at a greater distance from a closer one of the two sides on which the light source is to be exposed, as compared to a smaller distance. The number per unit area when viewed perpendicular to the emission surface is not reduced,

The light guide plate according to claim 1.

1 2. A first sub-compartment formed of a transparent material, which is a sub-compartment not containing the scattering particles,

The first sub-section is located at a location where the distance from a closer one of the two sides where the light source is to be projected is larger, and where the distance is smaller than that. And the second sub-division has a greater distance from the closer one of the two sides on which the light source is to be exposed, as compared to At larger locations, the thickness is not reduced compared to locations at shorter distances.

The light guide plate according to claim 11, wherein:

13. The light guide plate is rectangular, and the light source is expected to face all sides thereof.

In each of the ranges in which the rectangle of the light guide plate is divided into four by a diagonal line, the scattering particles are compared with a place where the distance from the side at the end of the range is larger than a place where the distance is smaller. Then, the number per unit area when the light guide plate is viewed perpendicular to the emission surface is not reduced,

The light guide plate according to claim 1.

1 4. a first sub-compartment formed of a transparent material, the sub-compartment not including the scattering particles;

In each of the first subsections, in each of the four sections of the diagonal rectangle in the light guide plate, where the distance from the edge at the end of the range is larger, the location is smaller than the location where the distance is smaller. The thickness of the second sub-compartment is such that its thickness is not increased, and the second sub-compartment is located at a greater distance from the edge at the end of the area than at a smaller distance. 14. The light guide plate according to claim 13, wherein a thickness thereof is not reduced.

15. The density of the scattering particles in the second subsection is the same in any part of the second subsection.

The light guide plate according to claim 6, 8, 10, 10, 12, or 14.

16. Light from the light source is adapted to be introduced into the light guide plate from the first small section, The light guide plate according to claim 6, 8, 10, 10, 12, or 14.

17. The light guide plate is divided into a plurality of small sections,

The plurality of small sections are arranged in order from the side closer to the portion where the light source is expected to face, and the closer to the light source the refractive index of the transparent material that forms the smaller section is, Are being made smaller,

The light guide plate according to claim 1.

18. Each of the end faces of the plurality of sub-sections that are in contact with the adjacent sub-sections, the light coming into the sub-section next to the portion where the light source is expected to be exposed from one of the sub-sections. However, the direction of travel is changed so as to be refracted and approach the emission surface.

The light guide plate according to claim 17.

19. The refractive index of the transparent material forming the second small section is set to be larger than the refractive index of the transparent material forming the first small section,

A light guide plate according to claim 6, 8, 10, 10, 12, 14, or 16.

20. The light guide plate is formed by a multicolor molding method in which one of the small sections is formed, and then the adjacent small sections are formed one after another.

The light guide plate according to any one of claims 3 to 6, 8, 10, 10, 12, 14 to 18, or 19.

21. The method for manufacturing a light guide plate according to Claims 3 to 6, 8, 10, 10, 12, 14, 19, or 20. And

A method for manufacturing a light guide plate, wherein the light guide plate is manufactured by molding each of the small sections by a multicolor molding method.

22. A backlight in which a light source faces an end of the light guide plate according to any one of claims 1 to 20.

23. A liquid crystal display device comprising the backlight according to claim 22.