JP2002250915A - Surface light source device, image display device, and light control member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a light control member from being shaken within a frame during transport or the like by highly accurately positioning the light control member on the frame. SOLUTION: Each of first to fourth light control members 5 to 8 uses a first hole 24 formed on a first tongue-shaped piece 20 as a reference hole, and engages with the engagement projection of a frame in few gaps. Each of the first to fourth light control members 5 to 8 has a slot-shaped second hole 26 formed on a second tongue-shaped piece 21, extending in the Y axial direction, and having a widthwise dimension sufficient for engaging with the engagement projection of the frame in few gaps. Each of the first to forth light control members 5 to 8 has a slot-shaped third hole 31 formed on a third tongue-shaped piece 28, extending in the X axial direction, and having a widthwise dimension sufficient for engaging with the engagement projection of the frame in few gaps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device for planarly illuminating an image display section such as a liquid crystal display panel used for a portable personal computer, a navigation device, various monitors, and the like, and the surface light source device. Regarding the image display device,
In addition, the present invention relates to a light control member constituting the surface light source device and the image display device.

[0002]

2. Description of the Related Art For example, a liquid crystal display device as an image display device is used in a portable personal computer or the like and irradiates a liquid crystal display panel (image display unit) with planar illumination light emitted from a surface light source device. An image is displayed on the surface of the liquid crystal display panel.

FIG. 8 shows an example of a surface light source device 100 used in such a liquid crystal display device. In the surface light source device 100 shown in FIG. 8, a reflection sheet 102, a light guide plate 103, and a plurality of light control members 104 to 107 are sequentially stacked and housed inside a plastic frame 101. A fluorescent lamp 110 as a light source is housed in the frame 101 such that the fluorescent lamp 110 is positioned on the side surface (incident surface) 108 side. At 112, it is fixed to the frame 101. A liquid crystal display panel (not shown) is installed on the upper surface of the surface light source device 100 so that the surface light source device 100 is housed and fixed together with the liquid crystal display panel and the like in a case of a portable personal computer or the like (not shown). Has become.

The above-mentioned surface light source device 100 is transported as a single unit of the surface light source device until the liquid crystal display panel is assembled, so that the light guide plate 103 and the light control members 104 to 107 are provided.
The light guide plate 103 and the light control member 1 are separated from the frame 101 due to vibrations and shocks during transportation and the like.
04-107 etc. may be damaged or light control members 104-10
There is a possibility that dust may enter between the light guide plates 103 and the light control member 104. Therefore, as shown in FIG. 8, the conventional surface light source device 100 includes the light control member 10 located at the uppermost position.
7 are attached to the frame 101 with the tape 113 so that the light control members 104 to 107, the light guide plate 103, and the like do not separate from the frame 101 and fall apart.

[0005]

However, the surface light source device 1
In FIG. 8, the light guide plate 103, the light control members 104 to 107, and the like thermally expand due to the heat generated from the fluorescent lamp 110, so that both end edges of the uppermost light control member 107 are tapes 113, 113 as shown in FIG. When the light control member 107 is firmly fixed to the frame 101, the uppermost light control member 107 is deformed so as to rise from the other light control members 106 and wrinkles are generated, so that uniform and high quality surface illumination is difficult. Had the problem of becoming

SUMMARY OF THE INVENTION It is an object of the present invention to effectively limit the amount of play (shift) of the light control member while allowing the light control member to expand due to the heat of the fluorescent lamp.

[0007]

According to the surface light source device of the present invention, the light control member is positioned on the light exit surface side of the light guide plate.
The light guide plate and the light control member are accommodated in a frame, and light from a light source arranged along the incident surface of the light guide plate is emitted in a planar manner through the light guide plate and the light control member. I have. And the light control member of this surface light source device is:
A first tongue is formed at one side of the opposite side of the light control member in a direction substantially orthogonal to the light-incident surface of the light guide plate and at a portion near the light source, and the first tongue has a reference hole as a reference hole. A first hole is formed. In addition, the light control member has a second tongue piece formed on one side of the opposite side where the first tongue piece is formed and near a surface opposite to the light incident surface of the light guide plate, The second tongue has an elongated second hole extending in a direction along one of the opposite sides. In the light control member, a third tongue is formed on the other side of the opposite side, and the third tongue has an elongated third hole extending in a direction substantially parallel to an incident surface of the light guide plate. Holes are formed. Positioning means corresponding to each of the tongue pieces is formed on the frame.

Further, the surface light source device according to the present invention has the first
A line connecting the first hole and the second hole extends in a direction substantially perpendicular to the incident surface of the light guide plate, and a line connecting the first hole and the third hole is formed on the incident surface of the light guide plate. It is characterized in that it extends in a direction substantially parallel to the direction.

Further, an image display device according to the present invention includes the above-described surface light source device and an image display panel illuminated by the surface light source device.

[0010] The light control member according to the present invention is arranged on the light exit surface side of the light guide plate, and is housed in a frame together with the light guide plate and the light source arranged to face the incident surface of the light guide plate. It has become. The light control member has a first tongue formed on one side of the opposite side in a direction substantially perpendicular to the incident surface of the light guide plate and near the light source. A first hole as a hole is formed. Further, in this light control member, a second tongue piece is formed on one side of the opposite side on which the first tongue piece is formed and near a surface opposite to the incident surface of the light guide plate,
The second tongue has an elongated second hole extending in a direction along one of the opposite sides. In the light control member, a third tongue is formed on the other side of the opposite side, and the third tongue has an elongated third hole extending in a direction substantially parallel to an incident surface of the light guide plate. Holes are formed.

Further, in the light control member according to the present invention, the line connecting the first hole and the second hole extends in a direction substantially orthogonal to an incident surface of the light guide plate, and And the third
A line connecting the holes extends in a direction substantially parallel to the incident surface of the light guide plate.

[0012]

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

[First Embodiment] FIGS. 1 and 2 show a surface light source device 1 according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the surface light source device 1. FIG. 2 is a partial cross-sectional view of the surface light source device 1 shown in cross-section along the line AA in FIG.

(Schematic Configuration of Surface Light Source Device) As shown in these figures, a surface light source device 1 has a frame 2 for housing or fixing components, and a reflection sheet 3 which is sequentially stacked and housed in the frame 2. , A light guide plate 4 and first to fourth light control members 5 to 8, and a fluorescent lamp (light source) 11 housed in the frame 2 along the incident surface (one side surface) 10 of the light guide plate 4.
And a reflector 12 that reflects the light of the fluorescent lamp 11 and guides the light to the incident surface 10 of the light guide plate 4. As shown in FIG. 2, by disposing a liquid crystal display panel 13 as an image display panel above the fourth light control member 8, a liquid crystal display device 14 as an image display device is formed.

(Frame) Of these, frame 2 is P
It is formed in a substantially rectangular shape by injection molding a resin material obtained by kneading a white pigment into C (polycarbonate), PMMA (polymethyl methacrylate), ABS resin, or the like. A first housing portion 15 that houses and supports the first to fourth light control members 5 to 8 and mounts the reflector 12 that houses the fluorescent lamp 11.
The liquid crystal display panel 13 is moved to the uppermost fourth light control member 8.
And a second accommodating portion 16 for accommodating and supporting the surface with a small gap.

The frame 2 is provided on the light incident surface 1 of the light guide plate 4.
One side 17 of opposite sides 17, 18 in a direction substantially orthogonal to 0
The first to fourth light control members 5 to 8
Tongue support portions 22, 23 for supporting the second tongues 20, 21
Are formed so as to be notched. The tongue support 22 is formed with a columnar engaging projection (first positioning means) 25 that engages with the first hole 24 of the first tongue 20. A cylindrical engaging projection (second positioning means) 27 that engages with the second hole 26 of the second tongue piece 21 is formed on 23. In addition, the frame 2 has a third tongue formed on the first to fourth light control members 5 to 8 on the other side 18 of the opposite sides 17 and 18 in a direction substantially orthogonal to the incident surface 10 of the light guide plate 4. A tongue piece support portion 30 for supporting the piece 28 is formed so as to be cut out. And the tongue support 3
0 has a columnar engaging projection (third positioning means) 32 which engages with the third hole 31 of the third tongue piece 28.

(Light Control Member) The first light control member 5 is a light diffusion sheet disposed so as to face the light exit surface 33 of the light guide plate 4, and emits light emitted from the light exit surface 33 of the light guide plate 4. It is designed to spread. The second light control member 6 includes:
A first prism sheet disposed on the upper surface of the first light control member 5, and a plurality of prisms having a substantially triangular cross section are continuously formed on the upper surface side so as to be substantially parallel to the incident surface 10 of the light guide plate 4. In the light emitted from the first light control member 5, a light component in a plane orthogonal to the light incident surface 10 and the light exit surface 33 of the light guide plate 4 is converted into a normal direction of the light exit surface 33 of the light guide plate 4. It is designed to collect light. Further, the third light control member 7 is a second prism sheet disposed on the upper surface of the second light control member 6, and a prism having a substantially triangular cross section is provided on the upper surface side thereof. A large number of light beams are continuously formed so as to be substantially perpendicular to the light guide plate 10, and of the light passing through the second light control member 6, the light is parallel to the incident surface 10 of the light guide plate 4 and perpendicular to the emission surface 33 of the light guide plate 4. The light component in the plane to be
The light is condensed in the direction of the normal to the exit surface 33.
The fourth light control member 8 is a protective sheet having a light diffusion function, prevents damage to the other light control members 5, 6, 7, and uses the second and third light control members 6, 7 to prevent damage. The collected light is slightly diffused to widen the viewing angle of a person viewing the liquid crystal display panel 13.

These first to fourth light control members 5 to 8 are:
As shown in FIGS. 1 and 3, the light guide plate 4 is formed of a resin material having excellent light transmittance (for example, PET (polyethylene terephthalate)), and has a substantially rectangular shape corresponding to the emission surface 33 of the light guide plate 4. In addition, the length along the fluorescent lamp 11 (parallel direction, that is, the X-axis direction in FIG. 3) is larger than the length perpendicular to the fluorescent lamp 11 (Y-axis direction in FIG. 3). Is formed.

The first to fourth light control members 5
8, one of the opposite sides 34, 35 in a direction substantially perpendicular to the fluorescent lamp 11 (in other words, a direction substantially perpendicular to the incident surface 10 of the light guide plate 4) and the fluorescent lamp 11. A substantially rectangular first tongue piece 20 is formed in the closer portion, and a circular first hole 24 is formed in the first tongue piece 20 as a reference hole. The first hole 24 of the first tongue piece 20 is adapted to engage with an engagement projection (first positioning means) 22 of the tongue piece support portion 20 of the frame 2 with a slight gap (FIG. 4 (A)).

In each of the first to fourth light control members 5 to 8, one of the opposite sides 34 and 35 in a direction substantially orthogonal to the fluorescent lamp 11 and the light guide plate 4.
A substantially rectangular second tongue piece 21 is formed in a portion (upper part in FIG. 3) near the surface 36 on the side opposite to the light incident surface 10. Are formed. The second hole 26 is an elongated hole extending in the direction (Y-axis direction) along one side 34 of the opposite sides 34, 35, and its width direction dimension W 1 is the tongue piece supporting portion 2 of the frame 2.
3 is engaged with a small gap in the engagement projection (second positioning means) 27, and its length dimension L1 is in the Y-axis direction of the first to fourth light control members 5 to 8. The dimensions are such that thermal expansion can be absorbed (see FIGS. 3 and 4B).

In the first to fourth light control members 5 to 8, the other side 35 of the opposite sides 34 and 35 in a direction substantially orthogonal to the fluorescent lamp 11 and a portion close to the fluorescent lamp 11. A third tongue piece 28 having a substantially rectangular shape is formed in the third tongue piece 28, and a third hole 31 is formed in the third tongue piece 28. The third hole 31 is provided on the light incident surface 1 of the light guide plate 4.
0 is a long hole extending in a direction (X-axis direction) substantially parallel to 0. The width direction dimension W2 of the hole is
0 with a slight gap, and the length dimension L2 in the X-axis direction of the first to fourth light control members 5 to 8 is set. (Figures 3 and 4 (C))

The first to fourth light control members 5 to 8 thus formed are respectively connected to the first to third holes 24, 26, 31 of the first to third tongue pieces 20, 21, 28. Are the engagement projections 25 and 2
The tongue support portions 22, 23, 3 are engaged with the tongue pieces 7, 32.
0, and is positioned with respect to the frame 2, so that the frame 2 is prevented from moving in the first housing 15.
The means for restricting the reflection sheet 3, the light guide plate 4, and the first to fourth light control members 5 to 8 from rising from the frame 2 is not particularly limited, and a clip member as shown in FIG. 124. In addition, the engagement projections 25, 2
7, 32 are formed in a height dimension larger than the thickness dimension in which the first to fourth light control members 5 to 8 are superimposed,
The engagement with the first to third holes 24, 26, 31 is not easily released.

(Light Guide Plate) The light guide plate 4 is made of PC, PMMA,
As shown in FIGS. 1 and 2, the cross-sectional shape in a direction orthogonal to the fluorescent lamp 11 is a fluorescent lamp 1.
It has a wedge-shaped shape that becomes thinner as it goes away from 1, and the shape of the exit surface (upper surface) 33 is made to have a substantially rectangular shape. In the light guide plate 4, the light from the fluorescent lamp 11, which has entered the inside from the incident surface 10, propagates through the inside of the light guide plate 4, and in the course of the propagation, the light that enters the emission surface 33 at an angle smaller than the critical angle. The light exits from the exit surface 33. Various means for emitting light from the light exit surface 33 of the light guide plate 4 have conventionally been used (for example, a technique of forming a dot pattern or a matte surface for scattering light on the lower surface 37 of the light guide plate 4). It is known and can be appropriately selected from these and adopted.

(Reflection Sheet) The reflection sheet 3 is formed of a resin material having excellent light reflectivity (for example, white PET) in a sheet shape, and has a rectangular shape corresponding to the lower surface 37 of the light guide plate 4. And functions to reflect light emitted from the lower surface 37 of the light guide plate 4 and return the light to the inside of the light guide plate 4.
The reflection sheet 3 is supported by the first housing 15 of the frame 2 and the lower surface 38 of the reflector 12.

(Reflector) The reflector 12 is formed by bending a thin metal plate so as to surround the fluorescent lamp 11 so that the light of the fluorescent lamp 11 can be reflected and guided to the incident surface 10 side of the light guide plate 4. It is formed in a substantially U-shaped cross section. The rising wall 40 and the upper surface 41 of the reflector 12 are accommodated in the frame 2, and the lower surface 38 of the reflector 12 is
Thus, the lower surface 38 of the reflector 12 supports the lower surface of the reflection sheet 3.

(Operation / Effect of First Embodiment) As described above, the surface light source device 1 according to the present embodiment includes the first to fourth light sources.
Of the first tongue pieces 20 of the light control members 5 to 8 of FIG.
The hole 24 is formed so as to engage with the engagement protrusion 25 of the frame 2 with a small gap as a reference hole. Further, the surface light source device 1 according to the present embodiment has the second hole 26 formed in the second tongue piece 21 of each of the first to fourth light control members 5 to 8.
Are elongated holes extending in the Y-axis direction, and the width dimension W1 of the second hole 26 is a dimension that engages with the engagement protrusion 27 of the frame 2 with a slight gap. Therefore, the first to fourth
The light control members 5 to 8 are allowed to thermally expand in the Y-axis direction, but the first to fourth light control members 5 to 8 are displaced in the X-axis direction by the first holes 24 and the engagement protrusions. 25 and the engagement between the second hole 26 and the engagement protrusion 27. The surface light source device according to the present embodiment has a long hole shape in which the third hole 31 formed in the third tongue piece 28 of each of the first to fourth light control members 5 to 8 extends in the X-axis direction. And the third hole 3
The width dimension W2 is a dimension that engages the engagement protrusion 32 of the frame 2 with a slight gap. Therefore, the first to fourth light control members 5 to 8 are allowed to thermally expand in the X-axis direction, but the first to fourth light control members 5 to 8 are displaced in the Y-axis direction. It is suppressed by the engagement between the first hole 24 and the engagement protrusion 25 and the engagement between the third hole 31 and the engagement protrusion 32. This allows
The first to fourth light control members 5 to 8 of the surface light source device 1 according to the present embodiment include the engagement between the second hole 26 and the engagement protrusion 27 and the engagement between the third hole 31 and the engagement protrusion. 32, the first
Rotation with reference to the hole 24 is also prevented. Therefore, in the surface light source device 1 according to the present embodiment, the first to fourth light control members 5 to 8 are positioned with high precision with respect to the frame 2, and the first to fourth light control members 5 to 8 are transported or the like. The light control members 5 to 8 of 4 do not move in the frame 2, and no rattling is generated.

(Modification of First Embodiment) In the surface light source device 1 according to the present embodiment, an example in which the first to fourth light control members 5 to 8 are used has been described. However, the present invention is not limited to this. A light control member having a large number of prisms extending in a direction orthogonal to the incident surface 10 of the light guide plate 4 on the lower surface 37 of the light guide plate 4 and having a prism extending in a direction orthogonal to the prisms (Prism sheet) may be arranged on the exit surface 33 side of the light guide plate 4.

In the present embodiment, the light guide plate 4
As shown in FIG. 1 and FIG. 2, a cross-sectional shape is exemplified as a substantially wedge-shaped shape, but the present invention is not limited to this, and a cross-sectional shape may be a rectangular shape or another shape.

In the present embodiment, the first to third
Although the mode in which the engagement projections 25, 27, and 32 as the positioning means are formed on the frame 2 has been exemplified, the invention is not limited thereto.
May be formed.

[Second Embodiment] FIG. 5 is a plan view of first to fourth light control members 5 to 8 according to a second embodiment of the present invention.

As shown in FIG. 5, the first to fourth light control members 5 to 8 according to the present embodiment are configured such that the first hole 24 and the third hole 31 have the same X-axis direction line 44. It is formed so as to be located above. With such a configuration, the width dimension W2 of the third hole 31 is made smaller than the width dimension W2 of the third hole 31 in the first embodiment by the amount not affected by thermal expansion. be able to.
On the other hand, the third hole 31 is larger than the first hole 24 in the fluorescent lamp 1.
1 away from the first hole 24 from the fluorescent lamp 11.
The effect of thermal expansion is greater toward the third hole 31 by the difference between the size up to and the size from the fluorescent lamp 11 to the third hole 31. Therefore, according to the present embodiment, first to first
The positioning accuracy of the fourth light control members 5 to 8 with respect to the frame 2 is further improved, and the backlash of the first to fourth light control members 5 to 8 during transportation of the surface light source device 1 is more effective. Is prevented. Note that the first hole 24 and the third hole 31 are preferably formed as far as possible from the fluorescent lamp 11 side.

[0032]

As described above, in the present invention, in the light control member, the first tongue piece is formed on one side of the opposite side in the direction orthogonal to the incident surface of the light guide plate and on the portion near the light source, When the first positioning means is engaged with the first hole formed in the first tongue, the direction of the first tongue and the direction substantially perpendicular to the incident surface of the light guide plate with respect to the frame. The positioning is performed in a direction substantially parallel to the incident surface of the light plate. In addition, the light control member has a second side on one side where the first tongue piece is formed and a portion near the surface opposite to the incident surface of the light guide plate.
Is formed in the second tongue, and a second hole in the shape of a long hole extending in a direction along one side is formed in the second tongue, and the second positioning means is engaged with the second hole. The second
Are positioned in a direction substantially parallel to the incident surface of the light guide plate with respect to the frame. Further, the light control member has a third tongue formed on the other side of the opposite side in a direction orthogonal to the incident surface of the light guide plate, and the third tongue is formed in a direction substantially parallel to the incident surface of the light guide plate. An elongated third hole having an elongated hole shape is formed, and the third positioning means is engaged with the third hole, so that the third tongue piece is substantially perpendicular to the incident surface of the light guide plate with respect to the frame. Is positioned in the direction of movement. As a result, according to the present invention, the light control member is positioned with high precision with respect to the frame, the shift movement in the frame is effectively prevented, and the rattling occurs in the frame during transportation or the like. There is no.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a surface light source device according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the surface light source device taken along line AA of FIG.

FIG. 3 is a plan view of a light control member.

FIG. 4 is a partial plan view showing an enlarged part of a light control member. FIG. 4A is an enlarged plan view of a first tongue piece of the light control member, FIG. 4B is an enlarged plan view of a second tongue piece of the light control member, and FIG. Third light control member
It is an enlarged plan view of the tongue piece of FIG.

FIG. 5 is a plan view of a light control member according to a second embodiment of the present invention.

FIG. 6 is a partial perspective view illustrating an example of a fixing unit of the light control member.

FIG. 7 is a partial perspective view showing another example of the fixing means of the light control member.

FIG. 8 is an exploded perspective view of a surface light source device showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Surface light source device, 2 ... Frame, 4 ... Light guide plate, 5
... 1st light control member, 6 ... 2nd light control member, 7 ...
... the third light control member, 8 ... the fourth light control member, 10 ...
... incident surface (one side), 11 fluorescent lamp (light source), 1
3 liquid crystal display panel (image display panel), 14 liquid crystal display device (image display device), 20 first tongue piece, 2
1 second tongue piece, 24 first hole, 25 engagement projection (first positioning means), 26 second hole, 27
... Engagement projection (second positioning means), 28... Third tongue piece, 31... Third hole, 32... Engagement projection (third positioning means), 33. ... one side, 35
... the other side, 36 ... the opposite side

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme Court II (Reference) // F21Y 103: 00 F21Y 103: 00 (72) Inventor Tsutomu Arihara 2-30-1, Namiki, Kawaguchi City, Saitama, Japan Stock F-term in company Enplus (reference) 2H091 FA23Z FA41Z FA42Z LA02 LA04 5G435 AA08 AA17 BB12 BB15 DD11 EE05 EE27 FF06 FF08 GG24 KK03

Claims (5)

[Claims] The light guide plate and the light control member are accommodated in a frame such that the light control member is located on the light exit surface side of the light guide plate, and a light source arranged along the incident surface of the light guide plate is provided. The light control member comprises a light guide plate and a light control member, and the light control member comprises a light control member, and the light control member has one of opposite sides in a direction substantially orthogonal to an incident surface of the light guide plate of the light control member. And a first tongue piece is formed in a portion near the light source, a first hole is formed in the first tongue piece as a reference hole, and one of the opposite sides where the first tongue piece is formed A second tongue piece is formed on the side of the light guide plate and near the surface opposite to the incident surface of the light guide plate, and the second tongue piece has an elongated hole shape extending in a direction along one of the opposite sides. A second hole is formed, and a third tongue is formed on the other side of the opposite side.
A third hole having a slot shape extending in a direction substantially parallel to the incident surface of the light guide plate is formed in the tongue, and positioning means corresponding to each tongue is formed in the frame. Surface light source device. 2. A line connecting the first hole and the second hole extends in a direction substantially orthogonal to an incident surface of the light guide plate, and connecting the first hole and the third hole. 2. The surface light source device according to claim 1, wherein the light source extends in a direction substantially parallel to an incident surface of the light guide plate. 3. The surface light source device according to claim 1 or 2,
An image display device comprising: an image display panel illuminated by the surface light source device. 4. A light control member, which is arranged on an emission surface side of a light guide plate and is housed in a frame together with the light guide plate and a light source arranged to face an incident surface of the light guide plate, wherein: A first tongue is formed on one side of the opposite side in a direction substantially perpendicular to the incident surface and near the light source, and a first hole as a reference hole is formed in the first tongue; A second tongue is formed on one side of the opposite side on which the first tongue is formed and near a surface opposite to the incident surface of the light guide plate, and the second tongue is formed on the opposite side. A second hole having a long hole shape extending in a direction along one side of the third side is formed, and a third tongue piece is formed on the other side of the opposite side.
A light control member, wherein a third hole having a long hole shape extending in a direction substantially parallel to an incident surface of the light guide plate is formed in the tongue piece of (1). 5. A line connecting the first hole and the second hole, extending in a direction substantially orthogonal to an incident surface of the light guide plate, and connecting the first hole and the third hole. 5. The light control member according to claim 4, wherein the light control member extends in a direction substantially parallel to an incident surface of the light guide plate.