CN1170190C

CN1170190C - Backlight device of liquid crystal display

Info

Publication number: CN1170190C
Application number: CNB011046996A
Authority: CN
Inventors: 陈豪智
Original assignee: AU Optronics Corp
Current assignee: AUO Corp
Priority date: 2001-02-20
Filing date: 2001-02-20
Publication date: 2004-10-06
Anticipated expiration: 2021-02-20
Also published as: CN1371021A

Abstract

A backlight device includes a light guide plate, a reflection cover, and a light source. The light guide plate is provided with a light incidence side face, a first clamping side face and a second clamping side face, and the first clamping side face and the second clamping side face are respectively provided with a first clamping structure and a second clamping structure. The reflector is arranged beside the light incidence side surface of the light guide plate and is provided with a reflecting surface, an opening, a first side edge supporting member and a second side edge supporting member. The opening faces the light incident side surface, the first and second side support members extend toward the first and second engaging side surfaces, respectively, and the first and second side support members are provided with first and second coupling structures, respectively. The first and second connecting structures are combined with the first and second clamping structures respectively.

Description

The backlight liquid crystal display device

Technical field

The present invention relates to a kind of back lighting device (back light), particularly a kind of back lighting device that improves packaging efficiency, reduces light leak and minimizing thickness.

Background technology

Figure 1A shows a kind of known backlight liquid crystal display device stereographic map.As shown in the figure, known back lighting device comprises a framework 10, a light guide plate 40 and a reflex housing 30.Reflex housing 30 is with (the indicating) combination of the screw on screw 35 and the framework 10 side 32 of reflex housing 30 to be fixed on the framework 10.

Figure 1B is the exploded view that shows back lighting device among Figure 1A.As shown in the figure, a reflector plate 20 is arranged on the framework 10.Then with light guide plate 40 fixations on reflector plate 20, a pair of projection 42 on the light guide plate 40 is placed in the pickup groove 12 of framework 10.One fluorescent tube 34 is placed in the reflex housing 30, and the two sides 32 of reflex housing 30 are fixed on the framework 10 with 15 combinations of the screw on screw 35 and the framework 10 respectively.And then a pervasion component (dittusing means) 50 is arranged on the light guide plate 40, so that finish the configuration of this back lighting device.This pervasion component comprises a diffusion thin plate (diffusingsheet) 52, at least one prism thin plate 54 and a protective film 56, and protective film also can be used as second layer diffusion thin plate.At last, a display panel, for example a liquid crystal panel 60 is arranged on this back lighting device, in order to form a display, a LCD for example.

In LCD, increase the uniformity of luminance of LCD except using pervasion component and light guide plate, it is very big to the uniformity of luminance influence in LCD that the distance between fluorescent tube and the light guide plate is inserted size (insert dimension).When the distance between fluorescent tube and the light guide plate is too small, a bright line (Kido Mura) will appear in LCD, and light guide plate can be because of overheated and impaired.When the distance between fluorescent tube and the light guide plate is excessive, a concealed wire will appear in LCD, and the probability that light guide plate comes off will increase.In above-mentioned known technology, fluorescent tube and light guide plate are all via frame fixation.In the use of display, fluorescent tube also produces heat except producing light, therefore light guide plate produces the phenomenon of expanding with heat and contract with cold near fluorescent tube, thereby reduces the accuracy of distance between fluorescent tube and the light guide plate, also reduces the tolerance deviation of framework and light guide plate size simultaneously.In a word, known back lighting device is easy to generate the shortcoming of bright line or concealed wire.

At United States Patent (USP) U.S.5, in 815,227, disclosed a kind of backlight liquid crystal display device.As shown in Figure 2, have at least two locking teats 44 on the light guiding surface of light guide plate 40, and have at least two lock holes 36 on the reflex housing 30.With teat 44 combinations on lock hole on the reflex housing 30 36 and the light guide plate 40, light guide plate 40 just can be directly and reflex housing 30 combinations.Therefore, improved the accuracy of the distance between fluorescent tube and the light guide plate.

Yet the teat 44 on the light guide plate 40 increases the thickness of back lighting device, has also increased the thickness of LCD.In addition, light is guided out by teat 44 easily, produces light leak in the viewing area of LCD.In order to solve light leakage phenomena, make the position of teat 44 away from the viewing area of liquid crystal panel the area increase of light guide plate 40.Perhaps, use a light tight object to cover on the locking teat 44.Yet these two kinds of solutions are not that the area of increase display is exactly the thickness that increases display.Requiring now under the compact trend of display, the increase of display area or thickness all is a big shortcoming.

Summary of the invention

Therefore, in order to solve the above problems.The present invention proposes a kind of back lighting device, and it comprises: a light guide plate, a reflex housing and a light source.Light guide plate has a light incident side, one first engaging side and one second engaging side, and this first and second engagings side has one first snap-in structure and one second snap-in structure respectively.First snap-in structure and second snap-in structure are two projections.Reflex housing is arranged on by the light incident side of light guide plate, it has a reflecting surface, an opening, a first side supporting member and a second side supporting member, this opening is towards light incident side, and the first and second lateral support members extend towards the first and second engaging sides respectively, and this first and this second side supporting member be respectively equipped with one first connecting structure and one second connecting structure.First connecting structure and second connecting structure are two breach.This light source is fixedly installed in the reflex housing, and the light that distributes of light source can be via this reflecting surface reflection, and penetrates light incident side by opening and enter in the light guide plate.Wherein, first and second connecting structures respectively with first and second snap-in structure combination, with direct lightguide plate fixing and reflex housing, and the interval between light guide plate and the light source keeps a preset distance.First snap-in structure in the above-mentioned back lighting device is a projection, and first connecting structure is a breach, when first connecting structure and first snap-in structure in conjunction with the time, this projection is fastened in this breach.

An advantage of the present invention is that projection is positioned on two end side surface of light guide plate, has reduced the thickness of LCD.

Another advantage of the present invention is that projection is positioned on two end side surface of light guide plate, therefore is difficult for producing light leakage phenomena.

Incident side and reflex housing that another advantage of the present invention is a light guide plate directly are coupled, and have improved assembling efficiency.

Description of drawings

Figure 1A shows a kind of stereographic map of known back lighting device;

Fig. 2 B shows the exploded view of back lighting device among Figure 1A;

Fig. 2 shows the synoptic diagram of another kind of known back lighting device;

Fig. 3 shows the synoptic diagram of back lighting device of the present invention;

Fig. 4 A to Fig. 4 C shows the assembly drawing of light guide plate and reflex housing;

Fig. 5 A is the light guide plate of back lighting device of the present invention and the synoptic diagram of first kind of bonding state of reflex housing;

Fig. 5 B and Fig. 5 C are the light guide plate of back lighting device of the present invention and the synoptic diagram of second kind of bonding state of reflex housing.

Embodiment

Fig. 3 shows the exploded view of back lighting device of the present invention.This back lighting device can be applicable in the LCD.As shown in Figure 3, back lighting device of the present invention comprises a light guide plate 100, a reflector plate 200, a reflex housing 300 and a fluorescent tube 340.Reflector plate 200 is arranged on light guide plate 100 belows.Light guide plate 100 has a light guiding surface 110, a bottom surface 120, a light incident side (not shown), one first engaging side 130 and one second engaging side 131.Light guiding surface 110 is near the plane of light incidence 62 of a liquid crystal panel 60, and the bottom surface 120 of light guiding surface is arranged on reflector plate 200 tops.Light guide plate 100 also comprises first and second snap-in structures 140,141, and this first and second snap-in structure is two projections 140,141, and they are separately positioned on first and second engaging side 130,131.Reflex housing 300 is installed in by the light incident side of light guide plate, and it has a reflecting surface 310, an opening 330, a first side supporting member 320 and a second side supporting member 321.The direction of opening 330 is towards light incident side, and the first and second lateral support members 320,321 then extend towards the first and second engaging sides 130,131 respectively.Fluorescent tube 340 1 light sources, it is arranged in the reflex housing 300, and the light that distributes of fluorescent tube 340 can be via reflecting surface 310 reflections, and penetrates light incident side by opening 330 and enter in the light guide plate 100.The first and second lateral support members 320,321 are respectively equipped with first and second connecting structures 325,326.First and second connecting structures 325,326 are two breach 325,326, they respectively with 140,141 combinations of two projections so that directly lightguide plate fixing 100 and reflex housing 300, and distance maintaining one preset distance between light guide plate 100 and the fluorescent tube 340.

Fig. 4 A to Fig. 4 C shows the assembly drawing of light guide plate and reflex housing.Shown in Fig. 4 A, light guide plate 100 and surface level are inclination (its angle θ approximates 45 degree), and the opening 330 of reflex housing 300 is aimed in the light incident side 150 of light guide plate 100.Shown in Fig. 4 B, after light guide plate 100 is inserted the opening 330 of reflex housing 300 obliquely, the projection 140,141 of light guide plate 100 is aimed at the breach 325,326 of reflex housing 300 then.At last, shown in Fig. 4 C, rotate light guide plate 100 and make projection 140,141 be coupled in fully in the breach 325,326 of reflex housing 300.In assembling process, in order more to increase the convenience of installing, the projection that embodiments of the invention adopt has end face respectively, and these end faces slope inwardly relatively towards breach respectively.Shown in Fig. 4 C, breach 325 has a top drilling 3251 and a concave bottom 3252, and projection 140 has a projection upper surface with respect to top drilling 3251 places, projection 140 has a projection lower surface with respect to concave bottom 3252 places, the area of projection upper surface makes above-mentioned projection be wedge type greater than the area of projection lower surface.When projection lower surface area was zero, then projection was the triangle wedge type.

Shown in Fig. 5 A, the dual-side supporting member 320,321 of reflex housing can be designed to parallel form, i.e. the first and second lateral support members, 320, the 321 parallel light guide plate 100 that recline.Shown in Fig. 5 B, by side view as can be known, the dual-side supporting member 320,321 of reflex housing also can be designed to non-parallel mode.In the present embodiment, designed a kind of reflex housing with particular geometries.Reflex housing 300 also comprises a reflex housing bottom surface 360,360 of first side supporting member 320 and reflex housing bottom surfaces accompany an angle δ, this δ angle is default less than 90 degree, that is to say that the first and second lateral support members 320,321 slope inwardly relatively towards above-mentioned projection 140,141 respectively.When using LCD, light guide plate 100 near fluorescent tube can increase because of expanded by heating, and at this moment, light guide plate 100 will promote the first and second lateral support members 320,321, angle δ is increased thereby form one and admit the space, in order to the part of admitting light guide plate 100 to increase because of thermal expansion.The nonparallel dual side-edge supporting member 320,321 that is to say reflex housing 300 provides the space of light guide plate 100 thermal expansions.In addition, the dual side-edge supporting member 320,321 of this reflex housing can be clamped light guide plate simultaneously, thereby reduces because vibrations make reflex housing break away from the probability of light guide plate.

Shown in Fig. 5 C, by top view as can be known, the reflecting surface of first side supporting member 320 and reflex housing 300 (not indicating) accompanies an angle γ, and this γ angle is default less than 90 degree, and the dual side-edge supporting member of reflex housing can be designed to nonparallel another kind of lateral support member.The first and second lateral support members 320,321 are long slightly than the side length of light guide plate 100 in the distance near reflex housing opening 340 places; And suitable away from the side length with light guide plate 100 at reflex housing 300 openings 340 places.Just dual side-edge supporting member 320,321 slopes inwardly relatively towards light guide plate 100 respectively.When light guide plate 100 increased because of expanded by heating, light guide plate 100 can promote the first and second lateral support members 320,321, angle γ is increased and forms an accommodation space, in order to take in the part that light guide plate 100 increases because of thermal expansion.

In addition, a pervasion component 50 is set also on light guide plate 100, it comprises diffusion thin plate 52, at least one prism thin plate 54 and a protective film 56 in regular turn.At last, a liquid crystal panel 60 is arranged on the pervasion component 50, to form a LCD.

Though the present invention discloses as above with a preferred embodiment; but it is not in order to limit the present invention; any those of ordinary skill in the art; do not breaking away under the spirit and scope of the invention condition; all can make some changes and retouching, thus protection scope of the present invention with accompanying claims for defining.

Claims

1. A backlight device, said backlight device comprising:

A light guide plate, which has a light incident side, a first locking side and a second locking side, the first and the second locking sides respectively have a first locking structure and a second locking engagement structure, the first engagement structure and the second engagement structure are two bumps;

A reflection cover is arranged on the light incident side of the light guide plate, the reflection cover has a reflection surface, an opening, a first side support member and a second side support member, the opening faces the The light incident side of the light guide plate, and the first and the second side supporting members respectively extend toward the first and the second engaging side, and the first and the second The side support members are respectively provided with a first connection structure and a second connection structure, and the first connection structure and the second connection structure are two gaps; and

A light source is fixedly arranged in the reflector, and the light emitted by the light source can be reflected by the reflective surface, pass through the light incident side through the opening, and enter the light guide plate,

Wherein, the first and the second connecting structures are respectively combined with the first and second engaging structures, and when the first connecting structure is combined with the first engaging structure, the bump is engaged fit in the notch to directly fix the light guide plate and the reflection cover, and maintain a predetermined distance between the light guide plate and the light source.

2. The backlight device as claimed in claim 1, wherein said notch has a top opening and a concave bottom, said protrusion has a protrusion upper surface opposite to said top opening, said protrusion is opposite to There is a bump lower surface at the bottom of the depression, and the area of the bump upper surface is larger than the area of the bump lower surface.

3. The backlight device of claim 2, wherein the protrusion is a wedge shape.

4. The backlight device of claim 2, wherein the protrusion is a triangular wedge shape.

5. The backlight device as claimed in claim 1, wherein the reflector further has a reflector bottom surface, an angle is formed between the first side support member of the reflector and the reflector bottom surface, and the clip The angle is preset to be less than 90 degrees. When the light guide plate grows due to thermal expansion, the light guide plate will push the first side support member to increase the included angle to form a receiving space for receiving the The part of the light guide plate that grows due to thermal expansion.

6. The backlight device as claimed in claim 1, further comprising a reflective sheet disposed under the light guide plate.

7. The backlight device as claimed in claim 1, further comprising a diffusion member disposed above the light guide plate.

8. The backlight device as claimed in claim 7, wherein the diffusion member sequentially comprises a protective film, at least one prism sheet and a diffusion sheet.