JP2002343126A - Illuminating unit and its manufacturing method, and liquid crystal display equipment using illumination unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent certainly invasion of dust into a display domain, by using components, which constitute an illuminating unit and liquid crystal display equipment as they are, and to prevent a situation where a liquid crystal panel breaks. SOLUTION: While an upper end side of a side surrounding a light source 2 A of a reflective sheet 3 is bent, it is constituted so that this bending tip part 3a may touch the back 4a of a light compensation sheet 4 using resilience of the bending. The bent tip part 3a of the reflective sheet 3 is arranged so that it may reach and overlap the emitting surface D3 of the light guide plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting unit having a light source disposed on a side surface of a light guide plate, a method for manufacturing the same, and a liquid crystal display device using the lighting unit.

[0002]

2. Description of the Related Art In recent years, display devices for information devices, such as notebook personal computers and word processors, and display devices for video devices, such as portable televisions, video movies, and car navigation systems, have become lighter and thinner.
Liquid crystal display devices have come to be widely used taking advantage of the feature of low power consumption. In addition, in order to realize a bright display screen, many of these liquid crystal display devices adopt a configuration in which illumination light is applied from behind a display element by a built-in illumination unit. In this illumination unit, an edge light system in which a light guide plate is placed on the back surface of the display element and a line light source such as a fluorescent discharge tube is arranged on an end surface of the light guide plate,
The edge light method is often employed as a backlight method for a liquid crystal display device used in a notebook personal computer or the like, because it has a feature of being thin and having excellent luminance uniformity on a light emitting surface. In a liquid crystal display device used for a portable television, a car navigation system, or the like, in order to achieve both thinness and luminance, an edge light method using two or more fluorescent discharge tubes, or
In many cases, an edge light method using a U-shaped fluorescent discharge tube or a U-shaped fluorescent discharge tube is adopted.

In the edge light system, a fluorescent discharge tube is arranged outside a light guide plate. In order to further enhance the portability and space saving characteristics of a liquid crystal display device, a light guide plate, a fluorescent discharge tube, and a lead wire are used. The key point is how to store such members in a housing and make them compact. In addition, cost reduction by reducing the number of parts and the number of assembly steps is also important in pursuit of corporate profits. Further, products whose life has passed have to be discarded separately for each material in order to protect the environment. For this purpose, products having good dismantling properties are also required.

FIGS. 6 to 9 show a conventional edge light type illumination unit UT using a fluorescent discharge tube and a liquid crystal display LD having the same. This lighting unit UT
A flat transparent light guide plate 1 for transmitting light, and the light guide plate 1
And an L-shaped fluorescent discharge tube 2 bent into an L-shape on two sides of the four sides, and a light guide plate 1 for transmitting light emitted from the fluorescent discharge tube 2.
The reflection sheet 3 leading to the end face D1 is disposed. The light guide plate 1, the fluorescent discharge tube 2, and the like are held by the housing 9 to form an illumination unit UT. In the case 9,
The opening 10 is provided for the purpose of leading out the lead wire, reducing the weight of the housing 9, and mounting and fixing by the user.
Is provided. The opening 10 communicates with the outside of the lighting unit UT. The liquid crystal panel 11 and the front cover 12 are mounted on the lighting unit UT to form a liquid crystal display device LD (FIG. 6).

[0005] The reflection sheet 3 is also provided on the back surface of the light guide plate 1, and returns the light exiting from the back surface of the light guide plate 1 to the inside of the light guide plate 1 again, and irradiates the light emitted from the exit surface of the light guide plate 1. Has the role of increasing Also, the reflection sheet 3
Is a fluorescent discharge tube 2 of the left and right end faces D1 and D2 of the light guide plate 1.
Is bent along the end face D2 where the light guide plate 1 is not disposed, so that light reaching the end face D2 of the light guide plate 1 is reflected and returned to the inside of the light guide plate 1 again, thereby achieving effective use of light. Often. Further, the reflection sheet 3 is disposed so as to surround the fluorescent discharge tube 2, and reflects light emitted from the fluorescent discharge tube 2 toward the incident end face D 1 of the light guide plate 1, so that the effective use of light can be achieved. I'm trying. The bent front end portion 3a of the reflection sheet 3 is made up of the light guide plate 1 and the double-sided tape 7.
This prevents the reflection sheet 3 from trying to return vertically due to the repulsive force of bending. As the reflection sheet 3, a white resin film having a high reflectance is used. As shown in FIG. 9, the reflection sheet 3 is used after being cut into a predetermined shape, and the first folded portion S1 and the second
Is formed, and the first and second folded portions S1 and S2 are each perforated so as to be easily folded. In addition, on the side 3A of the reflection sheet 3 where the L-shaped fluorescent discharge tube 2 is arranged, two folded portions S1 and S2 are formed, and on the side 3B where the L-shaped fluorescent discharge tube 2 is not arranged. A folded portion S is formed in one place.

Here, as the reflection sheet 3, a portion around the fluorescent discharge tube 2 (this portion may be referred to as a “reflector”) and a portion on the back side of the light guide plate 1 are separated from each other. Although there is a configuration in which both are adhered with tape, the integrated configuration shown in FIG. 6 has the advantage that the lighting unit UT can be made thinner and the cost and the number of assembly steps can be reduced. In addition, inside the outer peripheral wall of the housing 9, there is also one having an inward protruding portion 9 </ b> A that protrudes toward the emission surface above the light guide plate 1 (see FIG. 5). further,
As the reflection sheet 3, there is also a configuration in which a portion around the fluorescent discharge tube 2 is surrounded in an arc shape, and the light exit surface of the light guide plate 1 is adhered via an adhesive 7 such as a double-sided tape.
The perforations are not formed on the reflection sheet 3 surrounding the fluorescent discharge tube 2 in a circular arc shape.

[0007] A light correction sheet 4 is disposed on the emission surface D3 of the light guide plate 1. The light correction sheet 4 includes a diffusion sheet, a prism sheet, and the like. By arranging an arbitrary number of sheets having various specifications as necessary, the light emitted from the light guide plate is diffused, and the uniformity of irradiation light is obtained. And high brightness. The light correction sheet 4 is a lighting unit UT of a type arranged up to the reflection sheet 3A surrounding the fluorescent discharge tube 2.
There is also a lighting unit of a type arranged only at the center of the light emitting surface D1 of the light guide plate 1 and not arranged up to the reflection sheet 3A surrounding the fluorescent discharge tube 2 (see FIG. 5).

Light guide plate 1, reflection sheet 3 and light correction sheet 4
In order to absorb a dimensional difference in thermal expansion due to a temperature change and a dimensional error during manufacturing, a clearance F
(F1, F2), F3, F4 are provided. That is, as shown in FIG.
A clearance F (F1, F2) between
F3 and F4 are provided. Here, the symbol F indicates the distance (clearance) between the upper end of the reflection sheet 3 and the inwardly protruding portion 9A of the housing 9, and the upper light correction sheet 4
The space (clearance) between A and the inwardly protruding portion 9A of the housing 9 is shown as F1, and the space between the lower light correction sheet 4A and the upper end of the reflection sheet 3 is shown as F2. In addition,
Symbols G, G1 and G2 indicate the entry path of dust, and symbol G
Reference numeral 1 denotes a dust entry path into the interval F1, and a symbol G
Reference numeral 2 denotes a path of dust entering the space F2.

On the other hand, the conventional lighting unit UT having the above configuration
In the manufacturing method of assembling, the step of bonding the bent front end 3a on the upper end side of the reflection sheet 3 to the light guide plate 1 via an adhesive 7 such as a double-sided tape was required. Also,
The invasion of dust generated at the time of assembling the illumination unit UT and the liquid crystal display device LD was an important problem.

[0010]

In the conventional lighting unit UT and the liquid crystal display device LD having the above-mentioned structure, dust is generated inside and outside the housing 9 and when the lighting unit UT and the liquid crystal display device LD are assembled. A major problem is how to prevent dust from entering the display area on which the liquid crystal panel 11 and the light correction sheet 4 are arranged (see symbols G, G1, and G2 in FIG. 6). That is, in order to absorb a dimensional difference of thermal expansion due to a temperature change of the light guide plate 1, the light correction sheet 4, and the reflection sheet 3 and a dimensional error at the time of manufacturing, a space F is provided between them and the housing 9. (F1, F
2), F3, and F4 are provided. Dust from inside and outside of the housing 9 and dust generated at the time of assembling the liquid crystal display device LD, etc., generate the above-described intervals F (F1, F2), F3, and F4.
There is a danger of invading the display area side via the. An opening 10 is provided on a side portion of the housing 9, and the opening 10 communicates with the space F, so that dust entering from the opening 10 enters the display area side. .

When dust enters the display area, the output light is blocked, causing uneven brightness. Also, the friction between the dust and the light correction sheet 4 damages members on the display area such as the light correction sheet 4. Problems occur. And the liquid crystal panel 1
Once dust enters between the lighting unit UT and the lighting unit UT, it is very difficult to remove the dust without dismantling. And it is not effective unless dust intrusion is prevented not only from the side where the fluorescent discharge tube 2 is arranged but also from the side where the fluorescent discharge tube 2 is not arranged.

In addition, when the user unexpectedly presses the surface of the liquid crystal panel 11 or drops the liquid crystal display device LD, the liquid crystal panel 11 made of glass is broken.

Further, the conventional lighting unit U having the above-described configuration
In T, the light guide plate 1 is coated with an adhesive 7 such as a double-sided tape.
It is necessary to adhere the tip 3a on the upper end side of the reflection sheet 3 to the light exit surface of the light emitting device, so that the adhesive 7 causes adverse effects. That is, since the adhesive 7 is different from the one refractive index of the light guide plate, the portion where the adhesive 7 is disposed has a higher luminance than the other portions, causing a problem of uneven luminance. Further, it is necessary to dispose the upper end side of the reflection sheet 3 between the light correction sheet 4 and the light guide plate 1 so that the thickness of the reflection sheet 3 and the adhesive 7 (reference F
5) The lighting unit UT was thick.

In order to solve such a problem, a method is conceivable in which a member for preventing dust intrusion is provided as a separate member in a dust intrusion path. However, in order to reduce the weight and size of the lighting unit UT and the liquid crystal display device LD, the size and weight from the light guide plate 1 to the outer shape of the liquid crystal display device LD are restricted, and another method for preventing dust from entering. The member is not provided around the light guide plate 1.

On the other hand, the conventional lighting unit UT having the above configuration
In the manufacturing method of assembling, the step of bonding the bent front end 3a on the upper end side of the reflection sheet 3 to the light guide plate 1 via an adhesive 7 such as a double-sided tape was required. Also,
The invasion of dust generated at the time of assembling the illumination unit UT and the liquid crystal display device LD was an important problem.

Therefore, a first object of the present invention is to prevent the intrusion of dust into the display area side by using the members constituting the lighting unit and the liquid crystal display device as they are,
It is an object of the present invention to provide a lighting unit that prevents a liquid crystal panel from being broken by an unexpected external force, and further prevents an adverse effect caused by an adhesive such as a double-sided tape, and a liquid crystal display device using the lighting unit. A second object of the present invention is to reduce the number of steps of bonding the upper side of the reflection sheet with an adhesive such as a double-sided tape or the like, and to surely prevent dust from entering the display area by a simple step. An object of the present invention is to provide a method of manufacturing a unit.

[0017]

According to a first aspect of the present invention, there is provided an illumination unit including a light source, a light guide plate for guiding light from the light source, and an opening at an incident end face of the light guide plate. A reflection sheet, a light correction sheet disposed on the light exit surface of the light guide plate, and a housing for holding these members. The reflection sheet has an upper end that surrounds the light source and is bent. The tip portion is configured to contact the back surface of the light correction sheet by utilizing the repulsive force of the bending, and the bent tip portion is configured to be overlapped with the emission surface of the light guide plate.

According to the present invention, the bent front end portion of the reflection sheet is configured to be in contact with the back surface of the light correction sheet by utilizing the repulsive force caused by the bending, and the bent front end portion is located on the emission surface of the light guide plate. Since it is configured so as to be overlapped, it is possible to prevent dust from entering the display area side from the space between the light emitting plate and the light correction sheet and the portion leading to the space without providing a separate member. In addition to this, it is not necessary to use an adhesive such as a double-sided tape on the exit surface of the light guide plate. Further, since the bent front end portion of the reflection sheet is configured to be superimposed on the emission surface of the light guide plate, a cushion-like display device such as a liquid crystal panel disposed on the irradiation surface side of the illumination unit is provided. By the function, the liquid crystal panel is broken, and the display device is protected from an unexpected external pressure or the like.

A lighting unit according to a second aspect of the present invention comprises:
Provided on the premise of the invention of claim 1, the light emitting device further comprises a polarizing plate mounted on the irradiation surface of the illumination unit, and the bent front end portion of the reflection sheet bent to overlap the emission side surface of the light guide plate has an outer periphery of the polarizing plate. It is characterized by being located outside.

According to the present invention, since the bent front end of the reflection sheet is located at a position where it does not interfere with the polarizing plate, the influence of the portion of the reflection sheet overlapping the light output side of the light guide plate does not occur on the polarizing plate. .

A lighting unit according to a third aspect of the present invention comprises:
On the premise of the invention of claim 1, the housing has conductivity, and the surface of the reflection sheet opposite to the fluorescent discharge tube has conductivity.

According to the present invention, it is possible to provide a shielding effect for preventing noise from entering electronic components such as a liquid crystal panel due to the influence of electromagnetic waves or the like emitted from the fluorescent discharge tube 2.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a lighting unit, comprising: a housing; In a method for manufacturing a lighting unit in which a light guide plate that guides light is provided and a light correction sheet is provided on an emission surface of the light guide plate, the light is reflected in a state where an upper end side of a reflection sheet surrounding a light source is bent to an irradiation surface side. A correction sheet is arranged, and the bent end portion of the reflection sheet is configured to be in contact with the back surface of the light correction sheet by using a repulsive force due to the bending, and is configured to be overlapped on the emission surface of the light guide plate. Features.

According to the present invention, when the light correction sheet is disposed on the light exit surface above the light guide plate after the upper end side of the reflection sheet is bent, the bent front end of the reflection sheet is caused by the repulsive force of the light correction sheet. Since it is configured to be in contact with the back surface, a separate process for processing the light correction sheet so as to be in contact with the back surface is not required, and dust can be prevented from entering in a simple process. Further, the step of applying an adhesive such as a double-sided tape to the light emitting surface of the light guide plate and bonding the bent front end portion of the reflection sheet and the light guide plate as in the related art becomes unnecessary. Further, when the liquid crystal panel is mounted on the lighting unit according to the present invention, since the load of the liquid crystal panel presses the bent end portions of the light correction sheet and the reflection sheet against the repulsive force of the reflection sheet, the reflection sheet is a predetermined one. Is adjusted to the bent state. Therefore, in the bending step of the reflection sheet, a step for adjusting the bending state of the reflection sheet is not required.

A liquid crystal display device according to a fifth aspect of the present invention comprises:
The lighting unit according to any one of claims 1 to 3, and a liquid crystal panel disposed on an irradiation surface side of the lighting unit.

According to the present invention, it is possible to prevent dust from entering the display area from the side where the light source is not disposed between the light correction sheet and the light guide plate by a simple process without providing a separate member. In addition, the liquid crystal panel can contribute to a reduction in the thickness of the liquid crystal panel. Therefore, a liquid crystal display device using an inexpensive, thin, and highly reliable lighting unit is obtained. In addition,
The liquid crystal panel to be used is mounted with a gap of 0.4 mm or less than the pixel size of the liquid crystal panel to be used.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, as shown in FIGS. 1 to 3, a light source 2, a light guide plate 1 on a flat plate for transmitting light from the light source 2, and a back surface of the light guide plate 1 are arranged. Reflective sheet 3 and a light correction sheet 4 disposed on the exit surface of the light guide plate 1
The illumination unit UT includes a housing 9 disposed at intervals so as to surround the reflection sheet 3. In the light source 2, one fluorescent discharge tube 2 that emits light when driven by a high-frequency alternating current (for example, 40 to 100 kHz) is arranged in an L-shape on two sides of the four sides of the light guide plate 1 (“L-shape”). Called "fluorescent discharge tube").

The housing 9 holds the light guide plate 1, the reflection sheet 3, the fluorescent discharge tubes 2 and the like from the left and right directions, and also holds the liquid crystal panel 11 at the same time. As such a housing 9,
There are various types, including a type that holds the light guide plate 1 and the like from above and below, and a type that is formed in a box shape from a resin molding material. The housing 9 is made of a metal such as a sheet metal, and includes an electronic component such as a liquid crystal panel 11 and the like under the influence of an electromagnetic wave or the like emitted from the fluorescent discharge tube 2 together with a conductive member such as a metal foil attached to the back surface of the reflection sheet 3. It has a shielding effect to prevent noise from entering the air. And the housing 9
The light guide plate 1 and the fluorescent discharge tube 2 are held in the lighting unit U
T is configured. A liquid crystal panel 11 is mounted on the lighting unit UT, and a front cover 1 is placed thereon.
2 are attached to form a liquid crystal display device LD. The front cover 12 is also a kind of housing. Reference numerals 11a and 11b in the figure indicate a pair of substrates of the liquid crystal panel 11. A color filter is provided on the inner surface of the upper substrate 11a, and a pattern for driving liquid crystal is provided on the inner surface of the lower substrate 11b.

The light guide plate 1 is made of a material such as acrylic which has optimum optical characteristics such as transmittance and refractive index necessary for light transmission. The light guide plate 1 is provided with a dot pattern or a groove pattern (not shown) whose shape is changed according to the distance from the fluorescent discharge tube 2 on the back surface. Light emitted from the fluorescent discharge tube 2 is collected on the incident side end face D1 of the light guide plate 1 and guided inside.

The reflection sheet 3 is made of a white resin film having a high reflectance, and is formed by being bent from the back surface of the reflection sheet 3. The light emitted from the fluorescent discharge tube 2 is efficiently guided to the incident end face D1 of the light guide plate 1 by being bent so as to surround the fluorescent discharge tube 2. One side of the reflection sheet 3 surrounding the fluorescent discharge tube 2 is bent from the first folded portion S1. The folded upper end is bent, and the bent front end portion 3a is configured to contact the back surface 4a of the light correction sheet 4 by utilizing the repulsive force generated by the bending. The thickness of the reflection sheet 3 is arbitrary depending on the material and the like as long as the thickness is such that the repulsive force is exerted.

On the other hand, the side 3B where the reflection sheet 3 and the fluorescent discharge tube 2 are not arranged is bent along the light guide plate end face D2. By being bent along the light guide end face D2, the light exiting from the end face D2 of the light guide plate 1 is returned into the light guide plate 1 again, and the light emitted from the surface of the light guide plate 1 is increased. I have. The reflection sheet 3 on the back surface of the light guide plate 1 has a function of returning the light that goes out from the back surface of the light guide plate 1 back into the light guide plate 1 and increasing the amount of illumination light that is emitted. As the type of the reflection sheet 3, in addition to the above-described integrated configuration, there is a type in which a portion around the fluorescent discharge tube 2 (this portion may be referred to as a reflector) and a portion on the back side of the light guide plate 1 are separated. However, the present invention is also applicable to such a reflection sheet 3.

As shown in FIG. 4, the reflection sheet 3 is
Only the first folded portion S1 is perforated, but the second folded portion S2 is not perforated. Here, the second folded portion S2 may also be perforated. However, in order to easily exert the repulsive force of the bent front end portion 3a of the reflection sheet 3, the second folded portion S2 may have a perforation. It is preferable that no perforations are provided. However, as long as it does not affect the repulsion, it is optional to perform perforations at predetermined intervals according to the implementation. The side 3B of the reflection sheet 3 where the fluorescent discharge tubes 2 are not disposed is slightly shorter than the side 3A where the fluorescent discharge tubes 2 are disposed.

The upper end side of the reflection sheet 3 is folded so that the bent front end portion 3a is in contact with the back surface 4a of the light correction sheet 4 by utilizing the repulsive force generated by the bending. As a result, the bent front end portion 3a and the light correction sheet 4 come into close contact with each other.
The dust H is prevented from entering the display area side from the side where the fluorescent discharge tube 2 is arranged at the interval H1 provided between the fluorescent lamps.
The reflection sheet 3 is in contact with the back surface 4a of the light correction sheet 4 by utilizing the repulsive force of the reflection sheet 3 itself, and is disposed on the light guide plate 1 without being bonded with a double-sided tape or the like. Therefore, it is not necessary to use an adhesive such as a double-sided tape on the light exit surface D3 of the light guide plate, thereby preventing uneven brightness due to the adhesive such as the double-sided tape.

The bent front end 3 of the upper end side of the reflection sheet 3
a is arranged so as to exert its repulsive force and come into contact with the light correction sheet 4 and reach the light exit surface D3 side of the light guide plate 1;
The bent tip portion 3a is configured to be overlapped on the light exit surface D3 side of the light guide plate 1. As a result, the liquid crystal panel 11 and other display devices disposed on the irradiation surface side of the illumination unit UT are cushioned to protect the liquid crystal panel 11 from breakage and the liquid crystal display device LD from being protected from unexpected external pressure. In addition to this, it is possible to prevent dust from intruding from the side where the fluorescent discharge tube 2 is not disposed between the light correction sheet 4 and the light guide plate 1 from the side where the fluorescent discharge tube 2 is not arranged.
It also contributes to the thinning of the T and the liquid crystal display device LD.

Here, as another example of the present embodiment,
As shown by the dashed line in FIG.
May be formed up to the incident side end face of the light guide plate, but since the thickness F of the light guide plate 1 is smaller than the thickness of the light guide plate 1 due to the thickness of the reflection sheet 3, the amount of incident light is relatively small. It is not suitable because of the problem that the brightness decreases and the brightness becomes insufficient.

Further, as shown in the conventional example, the light guide plate 1, the light correction sheet 4 and the reflection sheet 3 are provided around each of them so as to absorb a dimensional difference in thermal expansion due to a temperature change and a dimensional error in manufacturing. Intervals F (F1, F2), F3, F4 are provided. That is, as described above, the interval F (F1, F2) is set between the reflection sheet 3 or the light correction sheet 4 and the housing 9.
2), F3 and 4F are provided. The housing 9 has a lead wire to the outside and a lighter housing.
An opening 10 is provided for the purpose of attachment and fixing by the user, and the intervals F (F1, F2), F3, and F4 are defined by the opening 10.
Through the lighting unit UT.

The light correction sheet 4 (4A, 4B) is disposed on the light exit surface D3 of the light guide plate 1. The light correction sheet 4 is
This is for equalizing the output light of the illumination unit UT and increasing the luminance. In the present embodiment, one diffusion sheet 4A and one prism sheet 4B are used. The diffusion sheet 4A is a sheet-shaped optical member used for diffusing light from the fluorescent discharge tube 2 and uniformly irradiating the liquid crystal panel 11, and the prism sheet 4A is a transparent resin film and has a triangular shape. It has a structure with regular grooves. The light correction sheet 4 is not limited to the diffusion sheet 4A and the prism sheet 4B, but may be any number of sheets having various specifications as needed. However, the present invention is applicable without being limited to the specification and the number of sheets. A step 4c is formed on one of the left and right sides (left side in the drawing) of the light correction sheet 4. This is because the bent front end portion 3a of the reflection sheet 3 is superimposed on the light exit surface D3 of the light guide plate 1. The light correction sheet 4 is not bonded to any of the reflection sheet 3, the housing 9, the light guide plate 1, and the like, and is usually merely stacked. Some sheets are bonded to prevent displacement of the sheet 4. In any case, the effect of the present invention is not affected. The light correction sheet 4 is
There is also a lighting unit of a type arranged only at the center of the light exit surface D3 of the light guide plate 1 and not arranged up to the reflection sheet 3A surrounding the fluorescent discharge tube 2 (see FIG. 5).

Above the light correction sheet 4, a display rear side polarizing plate (polarizing plate) 13 is disposed. The outer surface 13a of the display back side polarizing plate 13 has a light guide plate 1 of the reflection sheet 3.
Is arranged on the inner side (center side) not overlapping with the bent front end portion 3a which is bent until overlapping with the emission side surface D3. The bending size of the reflection sheet 3 is set to overlap the emission side surface D3 of the light guide plate 1, but it is important that the reflection sheet 3 does not interfere with the display back side polarizing plate 13 to be installed thereon. The bent front end portion 3a of the reflection sheet 3 is located outside the display back side polarizing plate 13 so as not to overlap with the outer periphery 13a of the display back side polarizing plate 13. That is, the step 4c of the light correction sheet 4 is closer to the center of the light guide plate 1 than the step 4c of the light correction sheet 4, that is, the step 4c of the light correction sheet 4.
, One side (left end 13a) of the polarizing plate 13 is aligned and disposed. Therefore, a step 4c is generated in the light correction sheet 4 by the thickness of the reflection sheet 3 between the light guide plate emission surface D3 and the upper surface of the reflection sheet 3, but the overlapping portion of the reflection sheet 3 is Since the dimensions do not interfere with each other, the step can be absorbed by the display rear surface side polarizing plate 13.

The present embodiment is configured as described above and uses the repulsive force of the reflection sheet 3 to communicate with the distance H1 between the light exit surface D3 of the light guide plate 1 and the light correction sheet 4, and the distance. Dust can be prevented from entering the display area side from the portion F3. In particular, there is a high possibility that dust will enter from the vicinity of the opening 10 of the housing into which dust enters from the outside.
Is close to the fluorescent discharge tube 2, the gap F <b> 3 leading from the opening 10 of the housing to the display area can be closed, and dust can be prevented from entering the display area.
Since the bent front end portion 3a of the reflection sheet 3 is configured to be overlapped on the emission surface D3 side of the light guide plate 1, it is possible to prevent the liquid crystal panel 11 from being broken by an unexpected external pressure or the like. In addition, since the reflective sheet 3 does not require the use of an adhesive such as a double-sided tape, problems such as uneven brightness due to the adhesive can be solved. Furthermore, no gap is required between the light correction sheet 4 and the light guide plate 1 to hold the bent tip 3a on the upper end side of the reflection sheet 3 and the adhesive. The distance H1 between the light guide plate 1 and the light emitting unit UT and the liquid crystal display device LD can be reduced in thickness by reducing or eliminating the distance H1 between them. It is also possible to make it difficult for dust to enter from the side where is not arranged, and to prevent entry of the dust depending on the size of the dust.

Since the light correction sheet 4 of the present invention is a resin film and is easily bent, the end of the light correction sheet 4 is pushed up to the liquid crystal panel 11 side by the repulsive force of the reflection sheet 3, and the liquid crystal panel 11 Closely adhered. Therefore, dust entering from the gap G2 can be prevented.

In the present invention, the front end 3a of the reflection sheet 3 has been described as being in contact with the light correction sheet 4A.
Or the two-light correction sheet 4 (4
The same operation and effect can be obtained when the size of A, 4B) is reduced and the liquid crystal panel 13 is directly contacted.

In the lighting unit UT having the above structure, the housing 9 holds the fluorescent discharge tube 2, the light guide plate 1, and the like.
The liquid crystal panel 11 is disposed on the irradiation surface side of T, and the liquid crystal display device LD is assembled.

(Manufacturing Method of the First Embodiment) Next, when assembling the lighting unit UT of the first embodiment, the housing 9 has a predetermined shape in which a portion surrounding the fluorescent discharge tube 2 is formed. The reflection sheet 3 is arranged together with the fluorescent discharge tube 2. Next, after the light guide plate 1 and the fluorescent discharge tube 2 are installed at predetermined positions on the reflection sheet 3, the upper end side of the reflection sheet 3 is bent, and in this bent state, the light correction sheet 4 (4A, 4A) is bent.
Place B). In this case, the left and right ends of the light correction sheet 4 are bent at the bent front end 3 a of the reflection sheet 3.
Use a size that covers up to

When the upper end portion of the reflection sheet 3 is bent, a force for returning to the original vertical shape acts due to the repulsive force of the reflection sheet 3. Since the repulsive force of the reflection sheet 3 always acts in the direction of pressing the light correction sheet 4, this force is used,
By disposing the light correction sheet 4 in a state where the reflection sheet 3 is not adhered to any of them, the bent front end portion 3a of the reflection sheet 3 presses the back surface 4a of the light correction sheet 4 and comes into close contact therewith. Therefore, the prevention of dust intrusion can be realized by a simple process. Conventionally, a step of bonding the reflection sheet 3 to the light guide plate 1 with an adhesive 7 such as a double-sided tape 7 was required. However, this step is not required in the present embodiment.
This bonding step can be reduced. When the product is discarded, it is necessary to separate and discard the material according to the recent environment. However, since the double-sided tape 7 used in the conventional example is not fixed, the disassembly property is superior to the conventional one.

The liquid crystal panel 11 is mounted on the lighting unit UT assembled by the above-described manufacturing method. When the liquid crystal panel 11 is disposed, the liquid crystal panel 11 pushes down the light correction sheet 4 against the repulsive force of the reflection sheet 3 due to the load,
The bent front end portion 3a of the reflection sheet 3 is arranged on the emission surface D3 of the light guide plate 1. That is, the bent state of the reflection sheet is naturally adjusted by the load of the liquid crystal panel 11.
At this time, the bending dimension of the reflection sheet 3 surrounding the fluorescent discharge tube 2 should be such that it does not interfere with the display rear-side polarizing plate 13 which is to be installed thereon so as to overlap the emission side surface D3 of the light guide plate 1. is important. That is, the area of the emitted light that is limited by the bending of the reflection sheet 3 is larger than the display rear-side polarizing plate 13, so that the light guide plate emission surface D <b> 3 and the upper surface of the reflection sheet 3 correspond to the thickness of the reflection sheet 3. Although the stepped portion 4c is formed on the light correction sheet 4, the overlapping portion of the reflection sheet 3 is dimensioned so as not to interfere with the display backside polarizing plate 13, so that the stepped portion 4c is absorbed by the display backside polarizing plate 13. Is possible. In addition, the step of adjusting the reflection sheet 3 when manufacturing the lighting unit UT becomes unnecessary, and the lighting unit UT of the present invention can be manufactured with simple steps. Finally, the front cover 12 is attached, and the liquid crystal display device LD is completed.

In the present invention, the reflection sheet 3a is described as being in contact with the light correction sheet 4A. However, when the size of the light correction sheet 4 is reduced and the light correction sheet 4a is formed so as to be in contact with the light correction sheet 4B, the same applies. Thus, a similar effect can be obtained when the liquid crystal panel 11 is configured to be in contact with the liquid crystal panel 11.

In the present invention, the bent state of the reflection sheet 3 is adjusted by the load of the liquid crystal panel 11, but when the housing 9 is disposed between the light correction sheet 4 and the liquid crystal panel 11, Similar effects can be obtained by the shape of the housing 9.

(Second Embodiment) As shown in FIG. 5, the illumination unit of the present embodiment has a housing 9 in which a part thereof projects inward from the light exit surface above light guide plate 1. Side projection 9
A, the inward projecting portion 9A has a rear surface 9a
Is provided so that the height position of the light guide plate 1 is the height position of the light emitting surface of the light guide plate 1. Also, the light correction sheet 4 (4A, 4B)
Are disposed at the center of the light exit surface of the light guide plate 1 and are not disposed to the position of the reflection sheet 3A surrounding the fluorescent discharge tube 2 or the reflection sheet 3B on the side where the fluorescent discharge tube 2 is not disposed. Therefore,
In this type of illumination unit UT, as in the first embodiment, the bent front end portion 3a of the reflection sheet 3 is configured to come into contact with the back surface 4a of the light correction sheet 4 by utilizing the repulsive force generated by the bending. Can not be.

Therefore, the bent front end 3 of the reflection sheet 3
a is configured to make contact with the back surface 9a of the inwardly protruding portion 9A of the housing 9 by utilizing the repulsive force of the bending. That is, the bent front end 3a of the reflection sheet 3 is
The light guide plate 1 is configured so as to reach the light exit surface D3 and overlap with the light exit surface D3, and to be in contact with the back surface 9a of the inward projection 9A of the housing 9. Therefore, the same operation and effect as those of the first embodiment can be obtained.

The reflecting sheet 3 according to the present embodiment is configured to be in contact with the back surface 9a of the inwardly protruding portion 9A of the housing 9 and to overlap with the emission surface D3 of the light guide plate 1. This prevents dust from entering the space H1 between the light exit surface D3 of the light guide plate 1 and the light correction sheet 4 and the portion F3 communicating with the space, and there is no problem of uneven brightness due to the conventional double-sided tape. Moreover, the fact that the bent front end portion 3a of the reflection sheet 3 is configured to be in contact with the back surface 9a of the inwardly protruding portion 9A of the housing 9 means that the light correction sheet 4 is disposed at the center of the emission surface D3 of the light guide plate 1. However, even in a lighting unit of a type in which the reflection sheet 3 surrounding the fluorescent discharge tube 2 is not disposed, the distance between the light exit surface D3 of the light guide plate 1 and the light correction sheet 4 and the portion F3 communicating with the distance from the light emitting sheet F3 to the display area side. Dust can be prevented from entering.

When the liquid crystal panel 11 is disposed above the illumination unit UT having the above-described configuration, dust from the inside and outside of the housing 9 is removed from the display area on the display area side where the liquid crystal panel 11 is disposed. From being invaded,
The liquid crystal display device LD uses a thin, inexpensive, and highly reliable lighting unit.

(Manufacturing method of the second embodiment) In assembling the lighting unit of the present embodiment, after bending the upper end side of the side 3A surrounding the fluorescent discharge tube 2 of the reflection sheet 3, it is projected inward. A fluorescent discharge tube 2 is provided in a housing 9 having a portion 9A.
Is disposed together with the fluorescent discharge tube 2 in a predetermined shape having a portion surrounding it, and the repulsion force generated by bending of the bent front end portion 3a is used to form a reflection sheet 3 on the back surface of the inward projection 9A of the housing 9. The light guide plate 1 is configured so as to be in contact with the light guide plate 1 so that the bent front end portion 3a is overlapped with the light exit surface D3. After that, the light guide plate 1 is arranged on the emission surface side of the reflection sheet 3 and the light correction sheet 4 is arranged on the emission surface D3 of the light guide plate 1 in the same manner as in the first embodiment. In this case, the inner protruding portion 9a of the housing 9 is
The end is arranged so as to reach the bent front end 3 a of the reflection sheet 3.

When the upper end of the reflecting sheet 3 is bent, a force for returning to the original vertical shape is exerted by the repulsive force of the reflecting sheet 3. Since the repulsive force of the reflection sheet 3 always acts in the direction of pressing the inner side projection 9a of the housing 10,
By utilizing this force and arranging the light correction sheet 4 in a state in which the reflection sheet 3 is not bonded to any of them, the bent front end portion 3a of the reflection sheet 3 becomes the rear surface 4a of the light correction sheet 4.
To come into close contact with each other. Therefore, a separate process for processing the inner surface of the housing 9 so as to be in contact with the rear surface of the inward projection is unnecessary, and the intrusion of dust can be prevented by a simple process. Furthermore, conventionally, the reflection sheet 3
Is required to be adhered to the light guide plate 1 with an adhesive 7 such as a double-sided tape. However, in the present embodiment, this step is not required, so that this adhesive step can be reduced. Further, since the shape of the housing 9 is constant, even when the opening width 3h of the reflection sheet 3 is equal to or larger than the opening width 9h of the housing 9 due to the repulsive force,
When disposing the reflection sheet 3 in the housing 9, the reflection sheet 4 is pushed down against the repulsive force of the reflection sheet 3, and the reflection sheet 3 is disposed inside the housing 9. Therefore, when the repulsive force is not used, the bent state of the reflective sheet 3 must be adjusted so that the bent front end 3a of the reflective sheet 3 is in contact with the inner side projection 9a of the housing 9. According to the present invention, the reflection sheet 3 is
Since it is naturally adjusted by the shape of the housing 9 by arranging it in the position, it is not necessary to make an adjustment in the bending step, and the intrusion of dust can be realized in a simple step.

[0055]

In the first and second embodiments, as shown in FIG. 2, the reflection sheet 3 extends to the light exit surface D3 of the light guide plate 1; Although the gap H1 between the light correction sheet 4 and the light guide plate 1 is reduced or eliminated by using no adhesive, intrusion of dust is prevented. However, this is an effect exerted only at the gap H1. It is. In the embodiment, the light correction sheet 4 is in close contact with the liquid crystal panel 11 so that
Although dust entering through the gap G2 is prevented, this effect cannot be obtained if the light correction sheet 4 is hardly bent. Therefore, by reducing not only the interval H1 but also the interval H2 between the light correction sheet 4 and the liquid crystal panel 11, it is possible to effectively prevent a reduction in display accuracy due to dust. Therefore, the present inventors,
The following experiment was conducted in order to make the above-mentioned fixed interval H2 a dimension effective for preventing intrusion of dust that affects display accuracy.

Example 1 A transmissive liquid crystal panel 11 or a reflective liquid crystal panel 11 was mounted between the light correction sheet 4 and the liquid crystal panel 11 with an interval H2 of 0.4 mm or a pixel size. . As a result, dust larger than the size did not enter, and did not affect the display on the liquid crystal panel 11. From the relationship with the pixel size in the present invention, if dust smaller than the above-mentioned size enters, the pixel is not hidden at the time of screen display, and display failure does not occur.
Further, by mounting the liquid crystal panels 11 at the above intervals, even if the user presses the panel display surface by accident, the bent front end portion 3a of the reflection sheet 3 can keep the light guide plate 1 in place.
Is formed so as to be superimposed on the light exit surface D3, the bent front end portion 3a functions as a cushion, and it is possible to prevent the liquid crystal panel 11 usually made of glass from breaking.

(Comparative Example 1) The distance H between the light correction sheet 4 and the liquid crystal panel 11 is 0.5 mm or more than the pixel size.
2 was provided, and a transmissive liquid crystal panel 11 or a reflective liquid crystal panel 11 was mounted. As a result, the dust having the size described above invaded and affected the display on the liquid crystal panel 11. This is because, in view of the relationship with the pixel size in the present invention, when dust larger than the above-mentioned size invades, the pixel is hidden at the time of screen display, resulting in display failure.

As is apparent from the above embodiments, the mounting of the liquid crystal panel 11 at a distance of 0.4 mm or less or the pixel size of the liquid crystal panel 11 to be used allows the illumination unit UT and the liquid crystal display device to be mounted. In LD,
Intrusion of dust affecting the display on the liquid crystal panel 11 can be reliably prevented. Therefore, the light correction sheet 4
The distance H2 between the liquid crystal panel 11 and the liquid crystal panel 11 was manufactured as described above in the first embodiment. As a result, it is possible to prevent dust having a size at least affecting the liquid crystal display from entering the display area at the interval H2, and to effectively prevent a decrease in display accuracy due to dust. .

In the above embodiments, the case where the present invention is applied to the lighting unit UT using the L-shaped fluorescent discharge tube 2 has been described. It can be widely applied to lighting units. Further, in each of the above embodiments, the description has been made mainly on the side 3A of the reflection sheet 3 where the light source 2 is disposed, but the present invention employs the same configuration on the side 3B of the reflection sheet 3 where the light source 2 is not disposed. It can also be applied by
Further, as the reflection sheet 3, the first folded portion S1
However, the present invention can also be applied to a lighting unit that surrounds a portion around the light source 2 in an arc shape.

[0060]

According to the illumination unit and the liquid crystal display device of the present invention, the bent front end portion of the reflection sheet utilizes the repulsive force generated by the bending to make the back surface of the light correction sheet or the back surface of the inwardly projecting portion of the housing. Is configured to be in contact with
Since the bent front end is configured to be superimposed on the light exit surface of the light guide plate, the distance between the light exit surface of the light guide plate and the light correction sheet, the distance between the reflection sheet and the inward projection of the housing, and the like. It is possible to prevent dust from entering a portion communicating with these intervals. In addition, since it is not necessary to use an adhesive such as a double-sided tape on the light-emitting surface of the light guide plate, the distance between the spectral correction sheet and the light guide plate can be reduced, and there is also a problem of uneven brightness due to the conventional double-sided tape. It is possible to solve. Further, since the bent front end portion of the reflection sheet is configured to be superimposed on the emission surface of the light guide plate, a cushion-like display device such as a liquid crystal panel disposed on the irradiation surface side of the illumination unit is provided. By the function, the liquid crystal panel is broken, and the display device can be protected from an unexpected external pressure or the like.

According to the illumination unit manufacturing method of the present invention, the bent front end portion of the reflection sheet is brought into contact with the back surface of the light correction sheet and the back surface of the inward projection of the housing by utilizing the repulsive force generated by the bending. In addition, since the bent end portion is configured to be overlapped with the light exit surface of the light guide plate, the distance between the light exit surface of the light guide plate and the light correction sheet and the portion that communicates with the distance can be formed in a simple process. In addition to preventing intrusion of dust, the liquid crystal panel and other display devices disposed on the irradiation surface side of the lighting unit function as a cushion, which may break the liquid crystal panel or cause an unexpected external pressure on the display device. Etc. can be protected. Further, since it is not necessary to use an adhesive such as a double-sided tape on the light emitting surface of the light guide plate, it is not necessary to use this bonding step, and it is possible to prevent luminance unevenness due to the adhesive. Therefore, a thin lighting unit with high display accuracy can be manufactured by a simple manufacturing method.

[0062]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a lighting unit according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the first embodiment.

FIG. 3 is a plan view showing the lighting unit according to the first embodiment.

FIG. 4 is an exploded plan view showing the reflection sheet of the first embodiment.

FIG. 5 is a sectional view showing a configuration of a lighting unit according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional lighting unit.

FIG. 7 is a plan view showing a configuration of a conventional lighting unit.

FIG. 8 is a side view of a conventional lighting unit.

FIG. 9 is an exploded plan view showing the conventional reflection sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Fluorescent discharge tube (light source) 3, 3A, 3B Reflection sheet 3a Bending front end of reflection sheet 4, 4A, 4B Light correction sheet 4a Back surface of light correction sheet 4c Step 9A, 9B Inside side of housing Projecting portion 9a Back surface of inward projecting portion 10 Housing opening 11 Liquid crystal panel 11a, 11b substrate 13 Display back side polarizing plate (polarizing plate) D1 Incident end face of light guide plate D3 Light emitting surface of light guide plate G, G1, G2 Dust entry path H1 Distance between correction sheet and light guide plate H2 Distance on illumination surface of lighting unit S, S1, S2 Folded portion of reflection sheet F, F1, F2, F3, F4 Distance around reflection sheet, etc. (Clearing) F3 Portion of the surrounding area such as reflective sheet etc. UT Lighting unit LD Liquid crystal display

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 302 G09F 9/00 302 336 336J // F21Y 103: 00 F21Y 103: 00 F term (reference) 2H089 HA40 QA08 QA12 QA16 TA17 TA18 TA20 2H091 FA14Z FA23Z FA42Z LA02 LA07 LA12 LA18 5G435 AA11 BB12 BB15 EE09 EE12 EE27 FF03 FF06 FF08 GG24

Claims (5)

[Claims] 1. A light source, a light guide plate for guiding light from the light source, a reflection sheet having an opening at an incident end face of the light guide plate and arranged so as to surround the light source, and an emission surface of the light guide plate A light correction sheet, and a housing for holding these members. The reflection sheet has a bent upper end side surrounding the light source, and the bent front end portion of the light correction sheet is formed by utilizing a repulsive force generated by the bending. An illumination unit, wherein the illumination unit is configured so as to be in contact with a back surface, and is configured such that a bent end portion thereof is overlapped with an emission surface of the light guide plate. 2. A polarizing plate mounted on an irradiation surface of an illumination unit, wherein a bent end portion of the reflection sheet, which is bent until overlapping with an emission side surface of a light guide plate, is located outside an outer periphery of the polarizing plate. The lighting unit according to claim 1, wherein: 3. The lighting unit according to claim 1, wherein the housing has conductivity, and the surface of the reflection sheet opposite to the fluorescent discharge tube has conductivity. 4. A light guide plate in which a reflection sheet of a predetermined shape formed with a portion surrounding the light source is arranged on the housing together with the light source, and a light guide plate for guiding light from the light source is arranged on the irradiation surface side of the reflection sheet. In the method for manufacturing a lighting unit in which the light correction sheet is disposed on the light exit surface, the light correction sheet is disposed in a state where the upper end side of the reflection sheet surrounding the light source is bent to the light exit surface of the light guide plate,
The manufacturing of the lighting unit, wherein the bent front end portion of the reflection sheet is configured to be in contact with the back surface of the light correction sheet by utilizing the repulsive force generated by the bending, and is configured to be overlapped on the emission surface of the light guide plate. Method. 5. A liquid crystal display device, comprising: the lighting unit according to claim 1; and a liquid crystal panel disposed on an irradiation surface side of the lighting unit.