JP2003121652A - Light guide plate, illumination device, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide plate which has small loss of light and can increase illumination efficiency. SOLUTION: The light guide plate is equipped with a transparent member 20 which has a top surface 20a and a reverse surface 20b and 1st and 2nd flanks 22a and 22c extending in (x) and (y) directions crossing each other to connect with each other; and a partial area of the transparent member 20 is a light projection area S1 in which light traveling in the transparent member 20 in the (x) direction is projected out from the top surface 20a or reverse surface 20b and another partial area of the transparent member 20 is a light guide area S2 in which light entering the transparent member 20 from a light incidence surface part 24 provided on the 1st flank 22a is reflected by the 2nd flank and then guided to the light projection area S1. In the light guide area S2, a hole 26 forming a mirror surface 26a extending in the (y) direction at an interval to the 2nd flank 22c in the (x) direction is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate used for irradiating a desired planar area with light, an illuminator using the light guide plate, and a liquid crystal display device equipped with the illuminator.

[0002]

2. Description of the Related Art An example of a conventional liquid crystal display device is shown in FIG.
Shown in (a) and (b). The illustrated liquid crystal display device is a front light type reflective liquid crystal display device. This liquid crystal display device includes a liquid crystal panel 8 having a reflection plate 80 on a back surface thereof, a light guide plate 9 arranged in front of the liquid crystal panel 8,
And a light source 7. The light guide plate 9 includes a substantially rectangular flat plate-shaped transparent member 9a. Transparent member 9a
Has a mirror surface (a smooth surface capable of total reflection of light under a certain condition), and has side surfaces 90c and 90d extending in a direction intersecting with each other and connected to each other.
The side surface 90c is provided with a light incident surface portion 92 that faces the light source 7, and the side surface 90d is provided with a plurality of concave portions 93 that form a pair of V-shaped wall surfaces 93a. The back surface 90b of the transparent member 9a is a portion that functions as a light emitting surface and is planar. On the other hand, the surface 90a of the transparent member 9a is an uneven surface having a plurality of convex portions 91. Each convex portion 91 has two types of inclined surfaces 91a and 91b having different inclination directions.

In the liquid crystal display device having the above structure, the light emitted from the light source 7 enters the light guide plate 9 through the light incident surface portion 92, and a part thereof proceeds toward the side surface 90d. Of these lights, the light that has reached the wall surface 93a of each recess 93 is reflected so as to travel toward the side surface 90e of the light guide plate 9. In the traveling process of the light, the light that reaches the inclined surface 91a of the convex portion 91 is reflected so that the traveling direction thereof is rapidly changed, and enters the back surface 90b of the light guide plate 9.
When the incident angle of light on the back surface 90b is smaller than a predetermined critical angle for total reflection, the light is directly emitted to the outside of the light guide plate 9. As a result, the liquid crystal panel 8 is illuminated.

[0004]

However, the above-mentioned conventional device has the following problems.

That is, the light emitted from the light source 7 travels into the light guide plate 9 from the light incident surface portion 92 at a constant spread angle. Therefore, some of this light is shown in FIG.
As indicated by reference numeral n1, there was light that did not reach the side surface 90d and leaked to the outside from the side surface 90f of the light guide plate 9 as it was. Further, as indicated by reference numeral n2 in FIG.
After reaching the side surface 90f after being reflected by the side surface 90d, some light leaks to the outside from the side surface 90f.

The light emitted from the light source 7 is as shown in FIG.
Not only does it have a constant spread angle in the plan view shown in (b), but it also has a constant spread angle when viewed from the direction shown in FIG. 7, for example. Therefore, as shown in the same figure, part of the light emitted from the light source 7 is
Although it reaches d and is reflected toward the side surface 90e, most other light is reflected on the front surface 90a or the back surface 90a of the light guide plate 9.
The light was directly incident on b, or indirectly through the side surface 90d, at a small incident angle, and then emitted to the outside as it was.

As described above, in the prior art, a relatively large amount of the light that has entered the light guide plate 9 from the light source 7 is not guided to a certain area as the light emitting surface of the back surface 90b, and the other light is not. It leaks from the part to the outside of the light guide plate 9.
Therefore, in the past, the illumination efficiency was poor and it was difficult to brighten the display image on the liquid crystal panel 8. Further, when the amount of light emitted from a certain area of the back surface 90b is reduced as a whole, for example, the path of light emitted from the back surface 90b toward the liquid crystal panel 8 via the wall surface 93a of the recess 93 is different from that of other portions. The amount of light is relatively emphasized. As a result, that portion may appear as a bright line, and uneven illuminance on the display screen of the liquid crystal panel 8 may be noticeable.

The present invention has been conceived under such circumstances, and its object is to provide a light guide plate and a lighting device which have a small loss of light and can enhance the lighting efficiency. I am trying. Another object of the invention of the present application is to provide a liquid crystal display device capable of displaying bright images with less unevenness of illuminance on the screen.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention takes the following technical means.

The light guide plate provided by the first aspect of the present invention comprises a transparent member having a front surface and a back surface, and first and second side surfaces extending in the x and y directions intersecting with each other and connected to each other. And a partial region of the transparent member is a light emitting region that allows the light traveling in the x direction in the transparent member to be emitted to the outside from either the front surface or the back surface. In addition, the other part of the transparent member is configured to reflect the light incident on the transparent member through the light incident surface portion provided on the first side surface by the second side surface. A light guide plate serving as a light guide region for guiding to an emission region, wherein the light guide region has a mirror-like surface extending in the y direction at a distance from the second side surface in the x direction. There is a hole to It is characterized in.

In the present invention, a part of the light entering the transparent member from the light incident surface portion in the direction different from the second side surface is partially converted into the second by the mirror-like surface formed by the hole. It is possible to reflect the light toward the side surface of the transparent member, and it is possible to prevent it from leaking to the outside of the transparent member. Further, the light reflected by the second side surface from the first side surface or the other side surface of the transparent member in a direction that may be directly emitted to the outside can be directly reflected by the mirror-like surface. It is possible to prevent leakage to the outside. Therefore, the loss of light can be reduced and the illumination efficiency can be improved as compared with the conventional case. Further, by increasing the illumination efficiency in this way, it is possible to make it difficult to see a portion of the light emitting region where the amount of light is large as a bright line or a bright spot. In addition, when the incident angle of the light traveling from the second side surface is smaller than the critical angle of total reflection specified by the material of the transparent member, the specular surface transmits the light as it is. Therefore, there is no problem that the mirror-like surface unduly hinders the progress of light from the light guide region to the light emission region.

The light guide plate provided by the second aspect of the present invention includes a transparent member having a front surface and a back surface, and first and second side surfaces extending in the x and y directions intersecting with each other and connected to each other. And a partial region of the transparent member is a light emitting region that allows the light traveling in the x direction in the transparent member to be emitted to the outside from either the front surface or the back surface. In addition, the other part of the transparent member is configured to reflect the light incident on the transparent member through the light incident surface portion provided on the first side surface by the second side surface. A light guide plate, which is a light guide region that leads to the emission region,
Light reflecting means capable of reflecting received light is provided on the front surface and the back surface of the light guide region.

According to such a structure, the light reflecting means prevents or suppresses the light traveling from the light incident surface portion into the transparent member to the outside from the front surface and the back surface of the light guide region. Therefore, even with such a configuration, the illumination efficiency can be improved.

In a preferred embodiment of the present invention, the light reflecting means is a light reflecting film or a light reflecting member which covers the front surface and the back surface.

With such a structure, the light reflecting film or the light reflecting member can appropriately prevent the light traveling toward the front surface and the back surface of the light guide region from leaking to the outside.

In another preferred embodiment of the present invention, a plurality of concave grooves are formed on the front surface and the back surface of the light guide region, the wall surfaces being inclined with respect to the front surface and the back surface and extending in the y direction. And the light reflecting means is a wall surface of each of the concave grooves.

According to this structure, of the light that has traveled to the front surface and the back surface of the light guide region, the light that has reached the wall surface of each groove is reflected by this wall surface, and You can prevent it from leaking. Since each of the above-mentioned concave grooves may be formed at the same time when the transparent member is resin-molded, for example, simplification of manufacturing is also achieved.

In another preferred embodiment of the present invention, the light guide area is provided with holes forming mirror-like surfaces extending in the y direction at intervals in the x direction with respect to the second side surface. It is provided.

Such a constitution corresponds to a constitution in which the respective characteristic constitutions of the light guide plate provided by the first aspect and the light guide plate provided by the second aspect of the present invention are combined, It is more suitable to reduce the loss of light and improve the illumination efficiency.

In another preferred embodiment of the present invention, the second side face is provided with a plurality of recesses forming a wall surface capable of reflecting light, which is inclined with respect to the y direction.

With this structure, the light traveling from the light incident surface portion to the second side surface can be efficiently reflected in the x direction by the wall surface of each recess, and the light guide area to the light emitting area can be reflected. It is possible to appropriately cause the light to travel to.

An illuminating device provided by the third aspect of the present invention comprises a light guide plate provided by either the first or second aspect of the present invention and a light incident surface portion of the light guide plate. And a light source provided.

According to this structure, the first aspect of the present invention
Alternatively, the same effect as described with respect to the light guide plate provided by any of the second side surfaces can be expected, and irradiation of light to the desired planar area can be performed while preventing large unevenness in illuminance. The efficiency can be increased.

In a preferred embodiment of the present invention, the light incident surface portion of the light guide plate is inclined so as to form an acute angle with the second side surface, and the light source is a chip having a light emitting surface. In addition to the LED light source, the light emitting surface is inclined with respect to the second side surface such that the light emitting surface is parallel or substantially parallel to the light incident surface portion.

According to this structure, the incident angle when the light in the direction of going from the light source to the second side surface is incident on the light incident surface portion is small, and most of the light is incident on the light incident surface portion. Can be prevented from being reflected by. Further, in general, the luminous flux density of light emitted from a chip-shaped LED light source is maximum in a region directly in front of the light emitting surface thereof, but according to the above configuration, the light in the region where the luminous flux density is maximum is The light guide plate can be appropriately advanced toward the second side surface. Therefore, it is more suitable for increasing the light irradiation efficiency.

A liquid crystal display device provided by the fourth aspect of the present invention is a liquid crystal display device including a liquid crystal panel and an illuminating device for illuminating the liquid crystal panel. The lighting device provided by the third aspect of the present invention is used.

According to this structure, it is possible to reduce the unevenness of illuminance on the screen of the liquid crystal panel and to brighten the displayed image.

Other features and advantages of the present invention will be more apparent from the following description of the embodiments of the invention.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 and 2 show a first embodiment of the present invention. The liquid crystal display device A shown in FIG.
It is a front-light type reflective liquid crystal display device, and includes a liquid crystal panel 1 and an illuminating device B. The illuminating device B includes a light guide plate 2 and two light sources 3.

The light guide plate 2 is configured to include a transparent member 20 having a substantially rectangular flat plate shape and made of a highly transparent synthetic resin. The transparent member 20 includes a front surface 20a and a back surface 20b that are spaced in the thickness direction, a pair of first side surfaces 22a and 22b extending in the x direction in FIG. 2, and y that is orthogonal to the x direction.
It has the 2nd and 3rd side surface 22c, 22d extended in a direction. The above-mentioned plurality of surfaces of the transparent member 20 and the surfaces of the respective parts described later are all mirror-like. Therefore, when the light traveling in the transparent member 20 is incident on each surface of the transparent member 20 at an incident angle larger than the critical angle for total reflection specified by the material of the transparent member 20, the light is totally reflected. It will be.

The back surface 20b of the transparent member 20 is flat, and a certain region of the back surface 20b serves as a light emitting surface, as will be described later. A part of the surface 20a of the transparent member 20 is y
It is an uneven surface provided with a plurality of convex portions 21 extending in a uniform cross section in the direction. Each convex portion 21 has first and second inclined surfaces 21a and 21b inclined with respect to the back surface 20b. The first inclined surface 21a is a surface for reflecting, when receiving light traveling from the second side surface 22c toward the third side surface 22d, this light so as to be incident on the back surface 20b at a small incident angle. There is a flat surface inclined so that the portion closer to the third side surface 22d is closer to the back surface 20b than the portion closer to the second side surface 22c. Second inclined surface 21b
Is a surface for totally reflecting this light as much as possible when receiving the light traveling from the second side surface 22c toward the third side surface 22d so as not to leak to the outside of the light guide plate 2. , And the first inclined surface 21a has a planar shape inclined in the opposite direction.

The transparent member 20 has a light emitting area S1 for positively emitting light from the back surface 20b toward the outside,
It is roughly divided into a light guide region S2 for advancing light to the light emitting region S1. Specifically, the light emitting area S1
Is a region of the transparent member 20 in which the plurality of convex portions 21 are provided, and the light guide region S2 is a region of the transparent member 20 closer to the second side face 20c than the light emitting region S1.

A notch 23 is formed in a portion of the first side faces 22a, 22b corresponding to the light guide area S2 near the second side face 22c, and the light source 3 and the light guide plate 2 are formed.
A light incident surface portion 24 is formed to allow light to enter the inside. The light incident surface portion 24 is inclined with respect to the second side surface 22c so that the angle θ between the light incident surface portion 24 and the second side surface 22c is an acute angle. Angle θ
Is, for example, about 80 to 84 °, but is not limited to this angle. The light incident surface portion 24 has a planar shape. However, instead of this, the light incident surface portion 24 may be formed into a curved surface.

On the second side surface 20c of the transparent member 20, V
A plurality of recesses 25 that respectively form a pair of wall surfaces 25a and 25b having a letter shape are provided at appropriate intervals. The two wall surfaces 25 a and 25 b of each recess 25 are formed on the second side surface 20.
By inclining by appropriate angles βa and βb with respect to the other part of c, when the light traveling from the light source 3 is received, this light can be totally reflected in the x direction or a direction substantially parallel thereto. It is designed to serve as a light reflecting surface. As means for accurately reflecting the light totally reflected by the wall surfaces 25a, 25b in the above direction, for example, the angles βa, βb are changed according to the distance from the wall surfaces 25a, 25b to the corresponding light source 3. May be.
The plurality of recesses 25 may be at equal intervals or unequal intervals.

The second side surface 20 of the light guide region S2
A plurality of slit-shaped holes 26 are arranged in a line at a position separated from c by an appropriate distance. Each hole 26 penetrates in the thickness direction of the transparent member 20, and the pair of inner wall surfaces 26 a and 26 b of each hole 26 has the transparent member 20.
Is a plane having a constant width in the thickness direction of and extending in the y direction. In the present embodiment, since a plurality of (for example, three) holes 26 are arranged at appropriate intervals, each hole in the y direction is secured while ensuring the mechanical strength of the transparent member 20. It is possible to increase the total length of the inner wall surface 26a of 26. However, the present invention is not limited to this, and may have a configuration in which only one hole 26 having a relatively long dimension in the y direction is provided in the light guide region S2.

As well shown in FIG. 1, a light reflecting film 50 is formed on the front surface 20a and the back surface 20b of the light guide region S2 so as to cover these surfaces (in FIG. 2, the light reflecting film). 50 is omitted). The light reflection film 50 is formed on the wall surface 25 of each recess 25 on the second side surface 20c.
It is also formed on the plane portion excluding a and 25b. The light reflection film 50 is made of a material having a high light reflectance, and is formed of, for example, a vapor deposition film of aluminum or a white coating film. However, in the present invention, instead of the light reflection film, a metal member or the like formed separately from the transparent member 20 may be used to cover the above-mentioned portion of the transparent member 20.

An LED light source is used as the light source 3, and more specifically, an LED bare chip is used as it is as a light source, or an LED bare chip is made into a resin package in a chip shape using a resin having a light-transmitting property. What has been used is used. Each light source 3 is provided such that its light emitting surface 30 faces the light incident surface portion 24 in parallel or substantially in parallel (see FIG. 2).

As the liquid crystal panel 1, one having a conventionally known structure can be used, and has, for example, the following configuration. That is, as well shown in FIG.
The liquid crystal panel 1 includes a pair of substrates 1 made of glass or resin.
A liquid crystal 11 is sealed between 0a and 10b, and a plurality of electrodes 14a and 14b and alignment films 13a and 13b are provided on the inner surfaces of the pair of substrates 10a and 10b. A polarizing plate 16a is provided on the front surface of the substrate 10a. As a driving method, a simple matrix method (passive driving method) is adopted, and the plurality of electrodes 14a correspond to horizontal electrodes (scanning electrodes) and extend in the left-right direction in FIG.
Moreover, they are arranged in parallel at equal intervals in a direction orthogonal to the paper surface.
The plurality of electrodes 14b correspond to vertical electrodes (signal electrodes),
They extend in a direction orthogonal to the plane of the drawing and are arranged in parallel in the left-right direction of the drawing at equal intervals. The liquid crystal 11 is configured such that a voltage is applied to a portion where the two types of electrodes 14a and 14b intersect and overlap each other, and this portion serves as a dot-shaped pixel. Of course, in the present invention, an active drive system can be adopted as a drive system for the liquid crystal panel.

The substrate 10a is a transparent substrate, and each electrode 14a is a transparent electrode made of an ITO film or the like. On the other hand, each electrode 14b is a metal reflection electrode capable of reflecting light. This liquid crystal panel 1
In the above, when the light traveling from the front surface toward the liquid crystal panel 1 passes through the polarizing plate 16a, the substrate 10a, and the liquid crystal 11, it is reflected by the plurality of electrodes 14b toward the front surface of the liquid crystal panel 1. Has become. Of course, in the present invention, instead of such a structure using the reflective electrode, a structure in which a reflective plate is provided on the back surface of the liquid crystal panel 1 can be adopted. As the liquid crystal panel, one for color display may be used instead of one for monochrome display.

Next, the operation of the liquid crystal display device A having the above structure will be described.

In FIG. 2, when the two light sources 3 are driven to be turned on, the light emitted from each light source 3 emits light.
4 enters into the light guide plate 2 and some of them directly proceed to the second side face 22c. Of this light, the light that has reached the wall surfaces 25a or wall surfaces 25b of the plurality of recesses 25 is efficiently reflected toward the light emission region S1 by being totally reflected by those wall surfaces. In this case, the light may reach the inner wall surfaces 26a, 26b of the hole 26, but the light traveling in the x direction or a direction substantially parallel thereto has a small incident angle with respect to the inner wall surfaces 26a, 26b. It passes through these inner wall surfaces 26a and 26b as they are. Therefore, the presence of the holes 26 does not prevent the light from traveling from the light guide region S2 to the light emission region S1.

On the other hand, of the light that has entered the light guide plate 2 from each of the light incident surface portions 24, the light that travels in the direction away from the second side surface 22c, as indicated by the symbol N1, is the hole 2
After reaching the inner wall surface 26a of No. 6, this inner wall surface 26a
Thus, total reflection can be performed in the direction toward the second side surface 22c. In addition, from the light incident surface portion 24 to the second side surface 22.
In the light reaching c, as shown by a symbol N2, the light does not directly travel toward the third side surface 22d but travels at an angle at which it can be directly emitted to the outside from either of the first side surfaces 22a and 22b. Although there is light, such light can also be totally reflected by the inner wall surface 26a of the hole 26 toward the second side surface 22c. Thus, by reflecting the predetermined light toward the second side surface 22c by the inner wall surface 26a of the hole 26, the amount of light leaking to the outside of the light guide plate 2 via the first side surfaces 22a and 22b is reduced. It becomes possible to do. The light reflected from the inner wall surface 26a of the hole 26 toward the second side surface 22c is guided to the light emitting area S1 by repeating total reflection by the second side surface 22c and other surfaces thereafter. It is possible to increase the amount of light traveling to the emission area S1.

As is often shown in the enlarged view of the main part of FIG. 1, some of the light emitted from the light source 3 may also travel directly or indirectly to the front surface 20a or the back surface 20b of the light guide plate 2. is there. However, these lights are reflected by the light reflecting film 50 with high reflectance. Therefore, it is possible to prevent light from unnecessarily leaking from the front surface 20a and the back surface 20b of the light guide area S2 to the outside, which also prevents the light from exiting.
It is possible to increase the amount of progressing light to 1.

When the light travels in the light emission area S1, as shown in FIG. 1, the light incident on the second inclined surface 21b of the front surface 20a or the rear surface 20b at a certain incident angle or more is not reflected. Totally reflected by the surface. Therefore, by repeating such total reflection, light can be sequentially advanced to the entire area inside the light guide plate 2. On the other hand, the light that is totally reflected by the first inclined surface 21a of the front surface 20a is likely to change its traveling direction abruptly and enter the back surface 20b at an incident angle smaller than the total reflection critical angle. Therefore, a certain area of the back surface 20b serves as a light emitting surface, and a large amount of light is emitted downward from this surface and is applied to the liquid crystal panel 1. The light applied to the liquid crystal panel 1 is reflected by the electrodes 14b of the liquid crystal panel 1 toward the front surface of the liquid crystal panel 1, and is transmitted through the light guide plate 2 in its thickness direction. The image displayed on the panel 1 can be visually observed.

As described above, in this liquid crystal display device A, since the amount of progress of light into the light exit area S1 of the light guide plate 2 can be increased, the amount of light radiated to the liquid crystal panel 1 can be increased. By increasing the number, the liquid crystal display screen can be brightened. Moreover, if the light irradiation area is brightened in this way,
A part of the light emitting region S1 where the light amount distribution is larger than that of the other part can be made invisible as a bright line or a bright spot. Therefore, the quality of the liquid crystal display image can be improved.

As described with reference to FIG. 2, each light source 3
Since the light emitting surface 30 of is parallel to the light incident surface portion 24, the light emitted from each light source 3 is less likely to be reflected by the light incident surface portion 24. Therefore, it is possible to secure a sufficient amount of light that travels into the light guide plate 3. Further, the light emitting surface 30 of each light source 3 faces the second side surface 22c in a state of being inclined with respect to the second side surface 22c by an appropriate angle. For this reason, it becomes possible to efficiently propagate the light having a high luminous flux density that travels in front of each light source 3 to the second side surface 22c, which also improves the light irradiation efficiency of the liquid crystal panel 1. It becomes possible.

FIGS. 3 and 4 show a second embodiment of the present invention. In the drawings after FIG. 3, the same or similar elements as those in the first embodiment are designated by the same reference numerals as those in the first embodiment.

In the illumination device Ba of this embodiment, V is provided on the front surface 20a and the back surface 20b of the light guide region S2 of the light guide plate 2.
A plurality of concave grooves 28 that respectively form a pair of wall surfaces 28a having a letter shape are provided. The plurality of recessed grooves 28 extend uniformly in the y direction and are arranged in parallel in the x direction at appropriate intervals.

According to this structure, of the light that travels from the light source 3 into the light guide plate 2 and travels toward the front surface 20a and the back surface 20b, the light that reaches the wall surface 28a of each groove 28 is: It is possible to totally reflect by the wall surface 28a. Therefore, also with the above configuration, it is possible to reduce the loss of light and improve the illumination efficiency. As described above, in the present invention, as a means for reducing the leakage of light from the front surface and the back surface of the light guide region S2, it is also possible to apply means for providing a concave groove on the front surface and the back surface.

FIG. 5 shows a third embodiment of the present invention.

In this embodiment, a plurality of holes 26 are provided in the light guide region S2 of the light guide plate 2, and
A plurality of concave grooves 28 are provided on the front surface 20a and the rear surface 20b of the light guide region S2.

With this structure, the light is reflected by the inner wall surface 26a of each hole 26 toward the second side surface 22c, so that the light leakage is reduced and the concave groove 2 is formed.
Since the light is reflected by the wall surface 28a of No. 8, the effect of reducing light leakage can be obtained at the same time. Therefore, it is preferable for reducing the light loss and increasing the light irradiation efficiency.

The contents of the present invention are not limited to the above-mentioned embodiments. The specific configurations of the respective parts of the light guide plate, the illuminating device, and the liquid crystal display device according to the present invention can be modified in various ways.

In the present invention, the hole 26 provided in the light guide region S2 of the light guide plate 2 has, for example, the transparent member 20.
It can also be formed as a hole that does not penetrate in the thickness direction. Also in this case, it is possible to suppress the leakage of light by reflecting the predetermined light by the inner wall surface 26a of the hole 26. However, in order to further enhance the effect of suppressing light leakage, the hole 26 is formed in a through hole shape so that the width of the inner wall surface 26a of the hole 26 (the transparent member 2
It is preferable to increase the width (0) in the thickness direction).

The liquid crystal display device according to the present invention can be configured as a backlight type transmissive liquid crystal display device instead of the front light type reflective liquid crystal display device. In the case of the backlight system, the light exit surface of the light guide plate on which light is emitted is made to face the back surface of the liquid crystal panel so that the light enters the liquid crystal panel from the light exit surface of the light guide plate. It suffices that the light is transmitted as it is toward the front surface of the liquid crystal panel, and it is not necessary to change the basic configuration of the lighting device itself. The liquid crystal panel may have various configurations.

In the illuminating device according to the present invention, the specific number of light sources is not limited, and it is also possible to adopt a configuration using only one light source, for example. In this case, for example, the illumination device shown in FIG. 2 may be divided along the y-direction center of the light guide plate 2. Further, the specific type of the light source is not limited, and a light source other than the LED light source can be used. The x and y directions referred to in the present invention do not necessarily have to be orthogonal to each other, and may be directions intersecting with each other at an intersection angle other than a right angle.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1 and a partially enlarged sectional view thereof.

FIG. 3 is a cross-sectional view showing a second embodiment of the present invention.

FIG. 4 is a plan view of FIG.

FIG. 5 is a plan view showing a third embodiment of the present invention.

6A is a schematic side sectional view showing an example of a conventional technique, and FIG. 6B is a plan view of FIG.

FIG. 7 is an operation explanatory view of the conventional technique.

[Explanation of symbols]

A liquid crystal display B lighting device S1 light emission area S2 light guide area 1 LCD panel 2 Light guide plate 3 light sources 20 Transparent member 20a surface 20b back side 22a, 22b First side surface 22c Second side surface 22d Third side 24 Light incident surface 25 recess 25a Wall surface (of concave portion) 26 holes 26a Inner wall surface (mirror-like surface) 28 groove 28a Wall surface (with concave groove)

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13357 G02F 1/13357 // F21Y 101: 02 F21Y 101: 02 (72) Inventor Masanori Komura Saiin Mizozaki, Ukyo-ku, Kyoto 21st Town ROHM Stock Company F-term (reference) 2H038 AA52 AA55 BA06 2H091 FA14X FA23X FA45X FD22 LA18

Claims (9)

[Claims] 1. A front surface and a back surface, and x intersecting each other,
The transparent member has first and second side surfaces extending in the y direction and connected to each other, and a part of the region of the transparent member advances in the transparent member in the x direction. Light is made to be a light emitting area that allows the light to be emitted to the outside from either the front surface or the back surface, and the other part of the transparent member is provided on the first side surface. A light guide plate, which is a light guide region that guides light that has entered the transparent member from a surface portion to the light emitting region by being reflected by the second side surface, and the light guide region has the first light guide region. 2. A light guide plate, which is provided with holes forming mirror-like surfaces extending in the y direction at intervals in the x direction with respect to the side surfaces of 2. 2. The front surface and the back surface, and x intersecting each other,
The transparent member has first and second side surfaces extending in the y direction and connected to each other, and a part of the region of the transparent member advances in the transparent member in the x direction. Light is made to be a light emitting area that allows the light to be emitted to the outside from either the front surface or the back surface, and the other part of the transparent member is provided on the first side surface. A light guide plate, which is a light guide region that guides light entering the transparent member from the surface portion to the light emitting region by being reflected by the second side surface, and which is provided on the front surface and the back surface of the light guide region. Is a light guide plate, which is provided with a light reflecting means capable of reflecting received light. 3. The light guide plate according to claim 2, wherein the light reflecting means is a light reflecting film or a light reflecting member that covers the front surface and the back surface. 4. The front surface and the back surface of the light guide region are provided with a plurality of recessed grooves that are inclined with respect to the front surface and the back surface and form wall surfaces extending in the y direction, and the light reflection region is formed. The light guide plate according to claim 2, wherein the means is a wall surface of each groove. 5. The light guide region is provided with holes forming a mirror-like surface extending in the y direction at a distance from the second side surface in the x direction. The light guide plate according to any one of 1. 6. The second side surface is provided with a plurality of recesses forming a wall surface capable of reflecting light, which is inclined with respect to the y direction. Light guide plate. 7. A lighting device comprising: the light guide plate according to claim 1; and a light source provided facing a light incident surface portion of the light guide plate. 8. The light incident surface portion of the light guide plate is inclined so as to form an acute angle with respect to the second side surface, and the light source is a chip-shaped LED light source having a light emitting surface. The lighting device according to claim 7, wherein the light emitting surface is inclined with respect to the second side surface such that the light emitting surface is parallel or substantially parallel to the light incident surface portion. 9. A liquid crystal display device comprising a liquid crystal panel and an illuminating device for illuminating the liquid crystal panel, wherein the illuminating device according to claim 7 or 8 is used as the illuminating device. A liquid crystal display device characterized in that