WO2004055430A1

WO2004055430A1 - Light unit

Info

Publication number: WO2004055430A1
Application number: PCT/JP2003/016008
Authority: WO
Inventors: Tatsumi Okuda
Original assignee: Sanyo Electric Co., Ltd.
Priority date: 2002-12-18
Filing date: 2003-12-12
Publication date: 2004-07-01
Also published as: JPWO2004055430A1; AU2003289083A1

Abstract

Projection portions (22) are formed on the sides (26) of a rectangular light guide except the light incident side (44) and its opposite side (46). The projection portions (22) are fitted in the recess portions (24) formed in a frame (20), and thereby the light guide (16) is secured to the frame (20). A glass plate (38) of a liquid crystal display panel (18) is fixed to the frame (20) by means of double-sided adhesive tape (34). When an impact is given, the shock produced by the collision between the light guide (16) and the glass plate (38) can be lessened. The projection portions (22) are formed over the sides (26) of the light guide (16), and therefore no interference fringes of light composed of bright and dark lines appear near the sides (26). As a result the light guide (16) can have a size a little larger than the display area (28) of the liquid crystal display panel (18). Thus, a small, lightweight light unit hardly damaging the light guide and liquid crystal display panel when it receives an impact and producing no light interference fringes in the display area.

Description

Specification

Light Unite Technical Field

The present invention relates to a light unit, and more particularly to a light unit used for a liquid crystal display device provided in an information terminal device such as a mobile phone. Conventional technology

2. Description of the Related Art Conventionally, in an information terminal device such as a mobile phone, a sidelight system is often used as a backlight unit of a transmissive or transflective liquid crystal display device. FIG. 6 shows a general configuration of a display device adopting the sidelight method, in which a light guide plate 2 is used. According to the liquid crystal display device 1, the light 4 emitted from the LED (light emitting diode) 3 enters the light incident surface 2a of the light guide plate 2, and is formed on the lower surface (reflective surface) 2b of the light guide plate 2, for example. Reflected on the slopes of the numerous grooves 2 c,…. Then, the reflected light 4 is emitted from the upper surface (emission surface) 2 d of the light guide plate 2 and irradiates the liquid crystal display panel 5 disposed on the upper side. The light 4 irradiating the liquid crystal display panel 5 transmits through the liquid crystal display panel 5 and is emitted as a light beam for displaying an image or the like.

An exploded perspective view of the liquid crystal display device 1 is as shown in FIG. 7, and a cross-sectional view in an assembled state is shown in FIG. As shown in FIG. 8, the rectangular frame 6 has an inner frame 6b formed along the inner peripheral surface of the outer frame 6a. On the upper surface of the inner frame 6b, a lens sheet 7a, a light-shielding double-sided adhesive tape 7b, a polarizing plate 5a, a glass plate 5b, and a polarizing plate 5a are fixed in a stacked state. . The polarizing plate 5a, the glass plate 5b, and the polarizing plate 5a constitute a liquid crystal display panel 5. In a state in which each polarizing plate 5a is attached to the glass plate 5b, a light-shielding double-sided adhesive tape 7 is provided. b is adhered to the upper surface of the inner frame 6b. The light guide plate 2 is fitted and fixed to the inner side surface of the inner frame 6b. A reflection sheet 7g is adhered and fixed to the lower surface of the inner frame 6b via a double-sided adhesive tape 7f. In addition, a flexible printed cable (FPC) 7h shown in Fig. 7 is provided on the upper surface of the inner frame 6b. For example, three light emitting diodes (LEDs) 3 as light sources and a surge prevention diode 3S are provided. The light emitting diode 3, the light guide plate 2, the lens sheet 7a, the frame 6 and the like constitute a backlight unit 7.

According to the liquid crystal display device 1, as shown in FIG. 8, the glass plate 5b and the light guide plate 2 are fixed to the frame 6, and the movement with respect to the frame 6 is restricted (there is no rattling). When an impact is applied to the display device 1, the impact of the collision between the glass plate 5b and the light guide plate 2 is small, so that the display device 1 can be prevented from scratching each other.

In this display device 1, as a method of fixing the light guide plate 2 to the frame 6, as shown in FIGS. 8 and 9, a convex portion 2 e formed on the side surface of the light guide plate 2 is attached to the inner frame 6 b of the frame 6. A method of fitting into a concave portion 6c formed on the inner side surface of the housing is used.

Although not shown in the drawing, as a method of fixing the light guide plate to the frame, a protrusion is formed on a side surface of the light guide plate, a through hole is formed in the protrusion, and a pin formed on the frame is connected to the through hole. There is also a way to communicate. For example, it is disclosed in Japanese Patent Application Laid-Open No. Hei 9-146716 (published on Jun. 6, 1997) (see FIG. 5).

However, in the conventional liquid crystal display device 1, as shown in FIG. 10, when the three light emitting diodes 3 are turned on, the upper and lower portions of the convex portions 2 e formed on the left and right side surfaces of the light guide plate 2 are turned on. The interference fringes of light (interference fringes consisting of the bright line 9a and the 喑 part 9b) 9 extending into the display area (area divided by the vertical length A and the horizontal length B) from each end of appear. The interference fringes 9 make it difficult to see an image or the like displayed on the liquid crystal display panel 5. However, in FIG. 10, the interference fringes 9 are exaggerated.

Also, in the lighting device described in the above-mentioned publication, it is considered that such light interference fringes appear when the light guide plate 2 in FIG. 6 has a unique groove pattern. In this manner, the interference fringes 9 appear in the display area 8 because, as shown in FIG. 10, the convex portion 2 e has a vertical boundary (length A) 8 a in the rectangular display area 8. This is because the interference fringes 9 are arranged within a part of the area and are formed with a length HI shorter than the length A of the boundary edge 8a. This is because it is formed so as to extend obliquely downward from the upper and lower ends toward the display area 8.

Here, in order to prevent interference fringes 9 from appearing in the display area 8, frames 6 and It is conceivable that the widths F and D of the light guide plate 2 are increased so that the interference fringes 9 do not reach the display area 8 having the original size. However, in this case, the width F of the liquid crystal display device 1 is increased, and the liquid crystal display device 1 is bulky and heavy. Therefore, the liquid crystal display device formed as described above may not be applicable to a mobile phone or the like where reduction in size and weight is desired. Summary of the Invention

Therefore, a main object of the present invention is to provide a novel light unit.

Another object of the present invention is to prevent a light guide plate and a glass plate of a liquid crystal display panel from being easily damaged when subjected to an impact, and to prevent light interference fringes from appearing in a display area. The purpose is to provide a compact and lightweight light unit.

The present invention relates to a light unit of a liquid crystal display device having a predetermined display area, comprising a light guide plate and a frame for holding the light guide plate, wherein a side surface excluding a light incident surface and a counter light incident surface is provided. A light unit in which at least one of a concave portion and a convex portion that are continuous in at least a display area is formed on a light guide plate, and the other is formed on a frame.

According to the present invention, one of the concave portion and the convex portion is formed on the side surface of the light guide plate, the other is formed on the frame, and the concave portion and the convex portion are fitted to each other to fix the light guide plate to the frame. Can be attached. Therefore, when a shock is applied to, for example, a liquid crystal display device in which the light unit is provided, the collision caused by the collision between the glass plate of the liquid crystal display panel and the light guide plate can be reduced, so that the light unit is not damaged. It can be kept from touching and can be prevented from being damaged.

One of the concave portion and the convex portion formed on the light incident surface of the light guide plate and on the side surface excluding the light incident surface facing the light incident surface is at least within a range corresponding to the display area of the liquid crystal display panel. Since they are arranged continuously, interference fringes extending from the edges of the concave or convex parts may appear in non-display areas such as liquid crystal display panels, but should not appear in the display area. Can be.

Further, the light guide plate is formed in a rectangular shape, for example, in a rectangular shape, and the concave or convex portions are formed in the light guide plate. When formed over the entire side surface excluding the light incident surface and the anti-light incident surface, the interference fringes can be prevented from appearing from the end of the concave portion or the convex portion.

The reason why one of the concave portion and the convex portion is formed on the side surface excluding the light incident surface and the anti-light incident surface of the light guide plate is that even if the concave portion and the like are formed on the entire light incident surface and the anti-light incident surface, they are This is because light fringes appear near the surface, but no such fringes appear on other sides.

When a convex portion is formed on the side surface of the light guide plate, the light guide plate can be fitted into the frame and fixed so that the light emitting region on the surface of the light guide plate is not narrowed by the convex portion. In addition, interference fringes can be prevented from appearing. In other words, when the concave portion is formed on the side surface of the light guide plate, the emission area on the surface of the light guide plate becomes narrower by the depth of the concave portion. Therefore, in order to obtain a desired emission region, the light guide portion is increased by the depth of the concave portion. Requires a light plate. Therefore, providing the convex portion on the side surface of the light guide plate rather than providing the concave portion can further reduce the size and weight of the light unit.

According to the present invention, for example, a liquid crystal display device provided with a light unit can be used for, for example, a cellular phone or the like which may receive an impact. And, even if the glass plate of the liquid crystal display panel and the light guide plate collide with each other when the cell phone receives a shock, the shock can be reduced, so that each can be prevented from being damaged and damaged. Can be prevented. Thus, the life of the liquid crystal display device including the light unit can be extended.

Also, since it is possible to prevent light interference fringes from appearing in a predetermined area of the light guide plate corresponding to the display area of the liquid crystal display panel, it is possible to clearly see the image displayed by the liquid crystal display panel or the like. Can be.

Also, light interference fringes can be prevented from appearing on the light guide plate, and even if they do, the interference fringes can appear in the non-display area of the liquid crystal display panel without changing the size of the light guide plate. Light guide plates that are only slightly larger than the area can be used. Therefore, a small and lightweight light unit can be provided.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a perspective view showing a light guide plate included in a backlight unit according to one embodiment of the present invention;

FIG. 1 (B) is a partially enlarged view showing a convex portion formed on a side surface of the light guide plate of FIG. 1 (A);

FIG. 1 (C) is a partially enlarged cross-sectional view of the liquid crystal display device provided with the light guide plate of FIG. 1 (A) as viewed from the direction I C -I C of FIG. 2 (A);

2 (A) is a plan view of the liquid crystal display device of this embodiment shown in FIG. 1 (C); FIG. 2 (B) is a side view showing the liquid crystal display device of FIG. 2 (A);

FIG. 3 is a perspective view showing a light guide plate provided in a backlight unit according to another embodiment of the present invention:

FIG. 4 is a sectional view showing a liquid crystal display device including a light guide plate according to still another embodiment of the present invention;

FIG. 5 is a sectional view showing a liquid crystal display device including a light guide plate according to still another embodiment of the present invention;

FIG. 6 is a longitudinal sectional view schematically showing a conventional backlight type liquid crystal display device;

FIG. 7 is an exploded perspective view showing a conventional backlight type liquid crystal display device; FIG. 8 is a cross-sectional view of the conventional liquid crystal display device shown in FIG. 7 viewed from the direction of VIII-VIII in FIG.

FIG. 9 (A) is a perspective view showing a light guide plate provided in the conventional liquid crystal display device of FIG. 7; FIG. 9 (B) shows a convex portion formed on a side surface of the light guide plate of FIG. 9 (A). A partially enlarged view; and

FIG. 10 is a plan view showing the conventional liquid crystal display device of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

A liquid crystal display device to which a light unit according to one embodiment of the present invention is applied will be described with reference to FIG. 1 and FIG. The light unit 10 is a backlight unit of a transmissive or transflective liquid crystal display device 12, and employs a sidelight system. To use. The liquid crystal display device 12 is used, for example, in a mobile phone. The basic configuration, that is, the configuration of the LED (light emitting diode) 14 as a light source, the light guide plate 16 and the liquid crystal display panel 18 is the same as that shown in FIG. Is omitted. Note that a lamp may be used instead of the LED 14.

The difference between the liquid crystal display device 12 of this embodiment shown in FIG. 2 (A) and the conventional liquid crystal display device 1 shown in FIG. 10 is the backlight units 10 and 7. The difference between the backlight unit 10 of this embodiment shown in FIG. 2 and the backlight unit 7 shown in FIG. 10 is that the light guide plates 16 and 2 and the frames 20 and 6 are formed. This is where the convex portions 22 and 2e differ from the concave portions 24 and 6c.

That is, in the conventional backlight unit 7 shown in FIG. 10, the convex portion 2 e is formed with respect to the vertical boundary edge (length A) 8 a in the rectangular display area 8 formed on the liquid crystal display panel 5. It is located within a part of the area, and is formed by H1, whose length is shorter than the length A of the boundary 8a.

On the other hand, in the backlight unit 10 shown in FIG. 2 (A), a convex portion 22 is formed over the entire left and right side surfaces 26 of the light guide plate 16 having a substantially rectangular planar shape. The convex portion 22 has a vertical boundary (length A) 28 a in the rectangular display area 28 formed on the liquid crystal display panel 18. It is formed continuously over a predetermined length range on each extension line in the vertical direction of 28a, and its length is H2 (= C) longer than the length A of the border 28a. is there. Thus, except that the length, shape and range of the convex portion 22 and the concave portion 24 into which the convex portion 22 and the force S are fitted are different, it is the same as the conventional one shown in FIG. In order to make the explanation easy to understand, the display area 28 of the liquid crystal display panel 18 and the light emission area of the light guide plate 16 corresponding to the display area 28 are both referred to as display areas 28. explain.

The liquid crystal display device 12 includes a rectangular frame-shaped frame 20 as shown in the cross-sectional view of FIG. The frame 20 has an inner frame 30 formed along the inner peripheral surface of the outer frame 20a. The upper surface of this inner frame 30 is the same as that shown in FIG. The lens sheet 32, a rectangular frame-shaped double-sided adhesive tape 34, a polarizing plate 36, a glass plate 38, and a polarizing plate 36 are fixed in a stacked state. The polarizing plate 36, the glass plate 38, and the polarizing plate 36 constitute a liquid crystal display panel 18. With the respective polarizing plates 36 attached to the glass plate 38, a light-shielding double-sided adhesive tape is used. It is bonded to the upper surface of the inner frame 30 by 34. The light guide plate 16 is fitted and fixed to the inner side surface of the inner frame 30. Further, a reflection sheet 42 is adhered and fixed to the lower surface of the inner frame 30 via a double-sided adhesive tape 40 equivalent to that shown in FIG. In addition, a flexible printed cable (FPC) 41 equivalent to that shown in FIG. 7 is provided on the upper surface of the inner frame 30. This FPC 41 has, for example, three light emitting diodes 14 as light sources, and Surge prevention diode 14 S is provided. The light emitting diode 14, the FPC 41, the light guide plate 16, the frame 20, the lens sheet 32, and the like constitute the backlight unit 10.

As shown in FIG. 1 (A), the light guide plate 16 constituting the backlight unit 10 is a rectangular plate-like body, and has vertical and horizontal lengths of C and D. Further, a convex portion 22 is formed on each of the left and right side surfaces. As shown in FIG. 1 (B), the convex portion 22 is a ridge having a rectangular cross section, and extends along the lower edge of each of the left and right side surfaces 26 over the entire length of each side surface 26. It is formed and has a length of H 2 (-C). However, when the light guide plate 16 is viewed from the plane, the light-entering surface 44 and the anti-light-entering surface 46 formed on the lower side and the upper side thereof have no projection 22 formed thereon.

The frame 20 has a rectangular outer frame 20a as shown in FIG. 2 (A). A rectangular inner frame 30 is formed inside the outer frame 20a. A concave portion 24 is formed on each of the inner side surfaces of the left inner frame 30a and the inner frame 30b constituting the inner frame 30. As shown in FIG. 1 (C), the recess 24 is a groove having a rectangular cross section, and is formed along the upper edge of each of the left and right inner surfaces over the entire length C of each inner surface. And the length is H 2 (= C). Each concave portion 24 formed in the frame 20 has a shape in which each convex portion 22 formed in the light guide plate 16 just fits. Therefore, the light guide plate 16 is formed to have dimensions (vertical length C and horizontal length D) substantially corresponding to the inner surface of the inner frame 30 of the rectangular frame 20 shown in FIG. The light guide plate 16 has the four sides facing the four inner sides of the inner frame 30. It is fitted into 20. However, no recess 24 is formed in the upper inner frame 30c and the lower inner frame 30d of the frame 20 shown in FIG. Each inner side surface of the rectangular inner frame 30 is formed as a reflecting surface that reflects light. The reflecting surface reflects light from the light guide plate 16 and returns the light to the light guide plate 16.

As shown in FIG. 1 (C), the rectangular reflection sheet 42 is formed by a double-sided adhesive tape 40 in which the upper surface of the outer edge along each of the four sides is formed in a rectangular frame shape. 0 is adhered to the bottom surface. The upper surface of the reflection sheet 42 is in contact with the lower surface of the light guide plate 16, and functions to reflect light from the light guide plate 16 and return the light to the light guide plate 16.

The lens sheet 32 is a rectangular sheet, and the outer edge along each of the four sides is an inner frame.

30 is fitted into a groove 48 formed on the upper surface of the inner edge. In this state, the upper surface of the lens sheet 32 and the upper surface of the inner frame 30 are flush. Then, a rectangular frame-shaped double-sided light-shielding double-sided adhesive tape 34 is attached so as to straddle the upper surface of the outer edge portion of the lens sheet 32 and the upper surface of the inner frame 30.

The liquid crystal display panel 18 is made up of polarizing plates 36 and 36 adhered to the upper and lower surfaces of a rectangular glass plate 38 in close contact with each other. As shown in FIG. 2A, the dimensions of the glass plate 38 in the vertical and horizontal directions correspond to the inner peripheral surface of the outer frame 20a of the frame 20. The lower surface of the outer peripheral edge of the polarizing plate 36 which is attached in close contact with the lower surface of the liquid crystal display panel 18 is attached to the upper surface of the light-shielding double-sided adhesive tape 34.

Since the liquid crystal display device 12 is configured as described above, the movement of the liquid crystal display panel 18 (glass plate 38) shown in FIG. It can be regulated by the inner frame 30 of 0. Then, the movement of the liquid crystal display panel 18 in the direction away from the light guide plate 16 (upward direction deviating from the frame 20) can be regulated by the adhesive force of the light-shielding double-sided adhesive tape 34.

In addition, the light guide plate 16 of the backlight unit 10 moves in the direction approaching the glass plate 38 of the liquid crystal display panel 18, and the convex portion 22 formed on the light guide plate 16 moves to the inner frame 30. It can be regulated by engaging with the side wall 24 a of the formed concave portion 24. The movement of the light guide plate 16 away from the liquid crystal display panel 18 (downward from the frame 20) is reflected by the reflection sheet 4 adhered to the inner frame 30. Can be regulated by two. As a result, the glass plate 38 and the light guide plate 16 of the liquid crystal display panel 18 are securely fixed to the frame 20. Therefore, for example, when the mobile phone provided with the liquid crystal display device 12 is dropped and a shock is applied to the liquid crystal display device 12, the glass plate 38 of the liquid crystal display panel 18 and the light guide plate 16 The impact caused by the collision can be reduced, so that they do not scratch each other and can be prevented from being damaged. As a result, the life of the liquid crystal display device 12 and the mobile phone can be extended.

In the knock light unit 10, the projections 22 are continuously formed over the entire left and right side surfaces 26 of the rectangular light guide plate 16 shown in FIG. 2 (A). It is necessary to prevent the linear light interference fringes (interference fringes consisting of the bright line 9a and the dark part 9b) 9 as shown in Fig. 10 from appearing from each of the upper and lower ends of the projection 22. it can. This makes it possible to prevent the interference fringes 9 from appearing in the display area 28 of the liquid crystal display panel 18. The left and right side surfaces 26, the light incident surface 44, and the anti-light incident surface 46 of the light guide plate 16 are formed along a non-display area of the liquid crystal display panel 18 (the outer periphery of the display area 28). Since they are arranged in 50 and they do not appear in the display area 28, the images etc. displayed in the display area 28 of the liquid crystal display panel 18 can be seen clearly. it can.

The reason why the convex portions 22 are formed on the left and right side surfaces 26 except for the light incident surface 44 and the anti-light incident surface 46 of the light guide plate 16 is that the convex portions 22 are formed on the light incident surface 44 and the opposite side. This is because, even if the light incident surface 46 is formed as a whole, light interference fringes appear near those surfaces, but such interference fringes do not appear on the other left and right side surfaces 26.

Also, since the projections 22 are formed on the left and right side surfaces 26 of the light guide plate 16, the light emission area of the surface of the light guide plate 16 is not narrowed by the projections 22, so that the light guide plate 1 6 can be fitted into the frame 20 and the interference fringes 9 can be prevented from appearing. That is, when the concave portion 24 is formed on the side surface 26 of the light guide plate 16, the surface of the light guide plate 16 has a depth corresponding to the depth of the concave portion 24 (depth corresponding to the width G shown in FIG. 1C). Although the emission area is narrowed, the light emission area on the surface of the light guide plate 16 is not narrowed by forming the convex portion 22 on the side surface 26. As described above, since the emission area of the light guide plate 16 does not become narrow, the size of the light guide plate 16 is increased to obtain a desired emission area. You don't have to. Therefore, the provision of the projections 22 on the side surface 26 of the light guide plate 16 can make the backlight unit 10 smaller and lighter than the provision of the projections 22.

However, in the above embodiment, as shown in FIG. 1A, the convex portion 2 2 (length H 2 (= H 2 (= C 2)) extends over the entire left side 26 (length C) of the light guide plate 16. 0), but instead, as shown in FIG. 3, a convex portion 22 is formed at the center of each of the left and right side surfaces 26 of the light guide plate 16 over a range of length Η3. The range of Η3 where each convex portion 22 is formed is a range corresponding to the vertical range Α in the display area 28 of the liquid crystal display panel 18 shown in FIG. 2 (Α). Therefore, when the interference fringes of light appear from each of the upper and lower ends of each convex portion 22 in a linear manner, for example, in a vertical direction with respect to each side surface, each interference fringe is a non-display area 50 of the liquid crystal display panel 18. Appears on the boundary between the display area 28 and the display area 28, but does not appear in the display area 28. Therefore, the images displayed in the display area 28 can be clearly seen. It can be.

When the interference fringes of light from the upper and lower ends of each convex portion 22 are directed to directions other than the direction perpendicular to each side surface and appear at a predetermined length, each interference fringe is displayed on the liquid crystal display panel 1. It is necessary to set the range (length) in which each projection 22 is formed so as not to appear in the display area 28 of FIG. Then, a concave portion 24 having a length corresponding to the convex portion 22 is formed in the inner frame 30 of the frame 20.

In the above embodiment, as shown in FIG. 1 (C), the cross-sectional shape of the convex portion 22 is rectangular, and the cross-sectional shape of the concave portion 24 is a rectangular cross-sectional shape corresponding to the convex portion 22. Alternatively, as shown in FIG. 4, the cross-sectional shape of the convex portion 52 may be a semicircle, and the cross-sectional shape of the concave portion 54 may be a semicircular cross-sectional shape corresponding to the convex portion 52. Similarly, as shown in FIG. 5, the cross-sectional shape of the convex portion 56 may be a trapezoid, and the cross-sectional shape of the concave portion 58 may be a trapezoidal cross-sectional shape corresponding to the convex portion 56.

In the above embodiment, the light unit 10 is applied as a backlight unit. However, the light unit 10 can be applied as a front light unit instead. Further, in the above embodiment, as shown in FIG. 2 (A), the convex portions 22 are formed on the left and right side surfaces 26 of the light guide plate 16, and the left inner frame 30 a and the right inner frame 30 a of the frame 20 are formed. The recesses 24 were formed in the inner frame 30, but instead of this, the recesses 2 were formed in the left and right side surfaces 26 of the light guide plate 16. 4 may be formed, and the protrusions 22 fitted to the recesses 24 may be formed in the left inner frame 30 a and the right inner frame 30 b of the frame 20. However, the convex portions 22 and the concave portions 24 are formed so that the movement of the light guide plate 16 in the direction toward the glass plate 38 can be stopped. In the above embodiment, as shown in FIG. 2 (A), convex portions 22 are formed on the left and right side surfaces 26 of the light guide plate 16, and the left inner frame 30 a and the right inner frame 30 a of the frame 20 are formed. The concave portion 24 was formed in the inner frame 30 b, but instead, the convex portion 22 or the concave portion 24 was formed on one of the left and right side surfaces 26 of the light guide plate 16, and the frame 20 was formed. The concave portion 24 or the convex portion 22 may be formed in the corresponding inner frame 30 to fit the two. By fixing one side surface 26 of the light guide plate 16 to the frame 20, it is also possible to reduce the impact on the light guide plate 16 and the glass plate 38.

Further, in the above embodiment, the light guide plate 16 having a rectangular planar shape has been described as an example, but the present invention can be applied to a light guide plate having a polygon other than a rectangle and other shapes. . When the light guide plate is formed in this manner, when interference fringes of light extending from the end of the convex portion 22 or the concave portion 24 formed on the side surface of the light guide plate appear, the interference fringes appear in the display area. What is necessary is just to determine the length and the range in which the convex part 22 or the concave part 24 is formed so as not to cause the problem.

Further, in the above-described embodiment, a groove (prism) is formed on the lower surface of the light guide plate 16 to form a reflection surface. However, other than this, for example, unevenness or the like may be formed to form a reflection surface.

While this invention has been described and illustrated in detail, it is obvious that it is used by way of example and example only and should not be construed as limiting, the spirit and scope of the invention being set forth in the appended claims. Limited only by the language of the claim.

Claims

The scope of the claims

1. A light unit of a liquid crystal display device having a predetermined display area, comprising a light guide plate and a frame for holding the light guide plate,

A light unit, wherein at least one of a side surface excluding a light incident surface and an anti-light incident surface has at least one of a concave portion and a convex portion continuous with the display region formed on the light guide plate, and the other formed on the frame.

2. The light unit according to claim 1, wherein the convex portion is formed on the light guide plate, and the concave portion is formed on the frame.