JPH10247412A - Surface light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen optical coupling loss between a light source through a recessed portion provided in a light guide plate for spreading light inside the light source and the light guide plate. SOLUTION: Approximately circular arc-like recesses 27 are provided in a light guide plate 22. Light emitting modules 25 are provided opposite to the recesses 27. Light sources are contained in sheathing cases 28 so as to form light emitting modules 25. Light outgoing face 23 side and its opposite face side of spaces between the light sources and the recesses 27 are covered by light reflection walls 34 extending from the cases 28 made of a white resin of high reflectance, and light R radiating slantingly upward and downward is reflected by the light reflecting wall 34 so as to prevent the leak of the light R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a surface light source device. In particular, it relates to a surface light source device used for a liquid crystal display device or the like.

[0002]

2. Description of the Related Art FIG. 1 is an exploded perspective view showing a conventional surface light source device 1, in which a plurality of concave portions 4 are cut in a substantially arc shape on one end surface (light incident surface 3) of a light guide plate 2 made of a transparent resin. The light emitting modules 5 are arranged so as to face the recesses 4 and the respective recesses 4. In addition, on the lower surface of the light guide plate 2, there is provided a reflection plate 7 for preventing light from leaking from a portion other than the light exit surface 6 to cause loss.

As shown in FIGS. 2A and 2B, a light emitting module 5 includes a light emitting diode (L) mounted on an electrode plate 8.
ED) A light source 9 such as a chip is housed in an outer case 10 in the shape of a rectangular box made of an opaque resin with an open front, and the light source 9 is sealed with a transparent resin 11. External electrodes 12 electrically connected to the electrode plate 8 are provided on both side surfaces of the outer case 10.

When the light R is emitted from the light emitting module 5 arranged to face the concave portion 4 of the light guide plate 2,
Light R emitted from the light source 9 enters the light guide plate 2 from the concave portion 4 of the light incident surface 3, spreads throughout the light guide plate 2 while repeating total reflection inside the light guide plate 2, and spreads from the entire light emission surface 6 (upper surface). Emit light to the outside. Moreover, since the light from the light source 9 is introduced into the light guide plate 2 from the concave portion 4, the light guide plate 2
When the light enters the inside, the light R from the light source 9 spreads horizontally as shown in FIG. This prevents only the area in front of the light source 9 from being brightened, thereby preventing luminance unevenness from occurring on the light exit surface 6 and making the luminance distribution on the light exit surface 6 uniform.

[0005]

The light emitting module 5 comprises:
In order to prevent light from escaping upward or downward, the light source 9 is housed in a box-shaped exterior case 10 made of an opaque resin. When the light R is disposed on the light incident surface 3 of the light plate 2, a space 13 that is open vertically is generated between the light source 9 and the recess 4 by the recess 4 for diffusing the light R to the left and right. For this reason,
As shown in FIG. 4, the light R emitted obliquely upward or obliquely downward from the light source 9 leaks from the space 13 to the outside,
There is a problem that the optical coupling efficiency between the light source 9 and the light guide plate 2 is reduced. When the optical coupling efficiency decreases, the luminance of the surface light source device 1 decreases by the loss.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and has as its object to reduce the optical coupling loss between a light source and a light guide plate due to a concave portion provided in the light guide plate. It is in.

[0007]

According to a first aspect of the present invention, there is provided a surface light source device for guiding light emitted from a light source from a light incident surface into a light guide plate, confining the light into the light guide plate, and extracting the light from the light exit surface of the light guide plate to the outside. In the light source device, a concave portion is formed on the light incident surface of the light guide plate, and the light source is disposed so as to face the concave portion, and the light emitting surface side and the opposite surface side of the space between the light source and the concave portion have light reflectivity. It is characterized by being covered by a member.

In the surface light source device of the present invention, since the light source is disposed so as to face the concave portion provided on the light incident surface of the light guide plate, light emitted from the light source is diffused from the concave portion to the light guide plate. Incident. Therefore, it is possible to prevent the brightness of the light guide plate from increasing only in front of the light source, and to make the brightness distribution of the surface light source device uniform. In addition, since the light emitting surface side and the opposite surface side of the space between the light source and the concave portion are covered by the light reflective member, the light emitted from the light source does not enter the light guide plate and is between the light source and the light guide plate. Can be prevented from leaking from the space to the light exit surface side and the opposite surface side, the light coupling efficiency can be improved, and the luminance of the surface light source device can be increased.

According to a second aspect of the present invention, in the surface light source device according to the first aspect, the light-reflective member is a part of an exterior member surrounding the light source and fits in the recess. It is characterized by being in.

Further, in the embodiment of the present invention, since a part of the exterior member surrounding the light source is a light-reflective member, the number of members does not increase, and the optical coupling efficiency does not increase. Even if a light-reflective member is provided in order to improve the cost, an increase in cost can be suppressed.

Further, since the light-reflective member is fitted into the concave portion of the light guide plate, the light-reflective member provided on the exterior member of the light source can be easily positioned by fitting the light reflective member into the concave portion of the light guide plate. And assemblability is improved.

According to a third aspect of the present invention, in the surface light source device according to the first aspect, the light-reflective member is a part of an exterior member surrounding the light source and overlaps a surface of the light guide plate. It is characterized in that the recess is covered as described above.

Also in the embodiment of the present invention, since a part of the exterior member surrounding the light source is made of a light-reflective member, the number of members does not increase and the optical coupling efficiency is improved. Even if a light-reflecting member is provided, the increase in cost can be suppressed.

Further, since the light-reflective member covers the concave portion so as to overlap the surface of the light guide plate, the light-reflective member provided on the exterior member is superposed on the surface of the light guide plate, thereby providing a light guide. The light source can be positioned in a direction perpendicular to the light reflecting surface of the light plate, and the assemblability is improved.

According to a fourth aspect of the present invention, in the surface light source device of the third aspect, a step is formed on an inner surface of the light-reflective member, and the step is formed on the light incident surface side of the light guide plate. Is characterized in that it is opposed to the end face.

Further, in the embodiment of the present invention, since the step portion is formed on the inner surface of the light reflecting member so as to face the end surface of the light guide plate on the light incident surface side, The light-emitting opening of the exterior member of the light source is smaller than the thickness of the light guide plate, and the light coupling efficiency can be further increased.

According to a fifth aspect of the present invention, in the surface light source device of the third aspect, a step is formed on a light emitting surface of the light guide plate so that an end portion of the light guide plate becomes thin, and the light reflection is performed. The light-reflecting member and the surface of the light guide plate are substantially flush with each other by placing a non-conductive member in the step.

According to an embodiment of the present invention, the light-reflecting member and the surface of the light-guiding plate are substantially separated by placing the light-reflecting member in a step provided on the light-emitting surface of the light-guiding plate. Since the surfaces are flush, the diffusion sheet and the liquid crystal display panel can be stably mounted even when the diffusion sheet and the liquid crystal display panel are arranged on the light emitting surface of the light guide plate.

According to a sixth aspect of the present invention, in the surface light source device according to the first aspect, the light-reflective member is a reflection tape attached between an exterior member surrounding the light source and the light guide plate. It is characterized by:

In the surface light source device according to the sixth aspect,
Since light is prevented from leaking from the space between the light source and the light guide plate by attaching a reflective tape between the exterior member and the light guide plate, it is inexpensive and has high versatility. Further, the exterior member of the light source can be fixed to the light guide plate with the reflection tape. In particular, when the reflection tape is continuously applied over the exterior members of the plurality of light sources as in claim 7, the assembly work is performed in comparison with the case where the reflection tape is applied to each exterior member of each light source. And speed up.

[0021] The embodiment described in claim 8 is the second embodiment.
7. The surface light source device according to 3 or 6, wherein a coupling member for coupling the light guide plate and the exterior member of the light source is provided on at least one of the light guide plate and the exterior member of the light source.

In the embodiment of the present invention, since the light source is coupled to the light guide plate by providing a coupling member on at least one of the light guide plate and the exterior member of the light source, an adhesive is used. Compared with the case where the exterior member etc. of the light source is bonded to the light guide plate, the curing curing time of the adhesive does not take much time,
Assembly time can be reduced.

[0023]

FIG. 5 is a perspective view showing a surface light source device 21 according to an embodiment of the present invention, and FIG. 6 is an enlarged exploded perspective view with a part thereof cut away. The surface light source device 21 mainly includes a light guide plate 22 having an upper surface serving as a light exit surface 23 and a light emitting module 25 disposed on a light incident surface 24 of the light guide plate 22.
And a reflection sheet 26 arranged opposite to the lower surface of the light guide plate 22.

The light guide plate 22 is formed of a transparent resin having a large refractive index such as polycarbonate or methacrylic resin, and has a light incident surface 24 having a plurality of recesses 27 cut out. The concave portion 27 has a substantially arc shape or a substantially V shape,
Although not particularly limited, such as a polygonal shape,
Is substantially semicircular, the light R from the light emitting module 25 incident on the light guide plate 22 can be uniformly diffused in each direction, and the luminance distribution can be made more uniform. In addition, a diffusion pattern (not shown) for emitting uniform light from the light exit surface 23 is formed on the lower surface of the light guide plate 22 by uneven processing, dot printing of diffuse reflection ink, or the like.

The reflection sheet 26 is provided on the light exit surface 2 of the light guide plate 22.
This is for preventing the light R from leaking from a position other than 3 and causing a loss. In FIG. 5, the reflection sheet 26 is provided only on the lower surface of the light guide plate 22, but other than the light incident surface 24 of the light guide plate 22. May also be provided on the outer peripheral surface of.

As shown in FIGS. 5 and 6, the light emitting module 25 is formed into a shape that fits into the recess 27 of the light guide plate 22 and fits almost exactly. As shown in FIGS. 7 and 8, the light emitting module 25 includes a light emitting diode (LED) die-bonded to a lead 29 and connected to a lead 30 by a bonding wire 31 in an outer case 28 made of a white resin having a high reflectance. A light source 32 such as a chip is housed therein, and the light source 32 is sealed with a transparent resin 33.

In this light emitting module 25, FIG.
As shown in FIG. 3, light R from the light source 32 is emitted forward and to the left and right sides through the transparent resin 33. The light reflecting walls made of white resin having high reflectivity are formed on the upper surface and the lower surface. 34 are formed.

The surface light source device 21 is assembled such that the light emitting module 25 is fitted into the concave portion 27 of the light guide plate 22, as shown in FIG. At this time, since the light emitting module 25 is positioned by the recess 27 in directions other than the vertical direction, the assemblability is improved. Thus, the light R emitted from the light source 32 of the light emitting module 25
Enters the light guide plate 22 through the concave portion 27 (light incident surface 24) of the light guide plate 22 through the transparent resin 33, and repeats total reflection in the light guide plate 22 or is reflected by the reflection sheet 26 so that the light guide plate is When the light is confined in the light emission surface 22 and the incident angle on the light emission surface 23 becomes smaller than the critical angle of total reflection, the light is emitted from the light emission surface 23 and the entire light emission surface 23 emits light in a plane.

Further, the light R emitted from the light source 32 and guided to the light guide plate 22 is refracted by the surface of the concave portion 27 when entering the light guide plate 22, thereby being diffused right and left as shown in FIG. You. Therefore, only the light source forward direction of the light guide plate 22 becomes brighter, and the light guide plate 22 is positioned between the light sources 32 and the light guide plate 2.
2 can be prevented from becoming dark, and the luminance distribution on the light emitting surface 23 of the surface light source device 21 can be made uniform.

Further, in the space 13 between the light source 32 and the concave portion 27, the light emitting surface 23 side and the opposite surface side are closed by the light reflecting wall 34 of the outer case 28. The light R reflected upward and downward from the light source 32 is reflected by the light reflecting wall 34, as shown in FIG. 7, so that the light R emitted from the light source 32 is transmitted to the outer case 28 and the light reflecting wall 34. The light is confined in the enclosed space 13 and is extracted only to the light incident surface 24 of the light guide plate 22.
Therefore, it is possible to prevent light from leaking upward or downward from the space 13 between the light source 32 and the light guide plate 22, and the light source 3
The light coupling efficiency between the light guide plate 2 and the light guide plate 22 can be improved, and the light amount loss can be reduced.

The light emitting module 25 does not necessarily need to be housed in the recess 27 as shown in FIG.
As shown in the surface light source device 35 shown in FIG. In FIG. 8, there is a gap between the light reflecting wall 33 and the concave portion 27, but this is to make it easier to see the drawing, and it is desirable that there is no gap.

(Second Embodiment) FIGS. 10 and 11 are an exploded perspective view and a partially broken plan view, respectively, showing a surface light source device 36 according to another embodiment of the present invention. 12 and 13 are a perspective view and a sectional view showing the light emitting module 25 used in the surface light source device 36. In this light emitting module 25, three leads 29 are provided in an outer case 28 made of white resin having a high reflectance.
a, 29b and 29c are insert-molded. At the light source mounting position, the outer case 28 is opened, and the light source mounting portions of the leads 29a, 29b, 29c are exposed from the outer case 28. In addition, from the upper edge and the lower edge of the opening 37 of the outer case 28, the light reflecting wall 34 having a shape matching the concave portion 27 so as to fit into the concave portion 27 of the light guide plate 22.
Is extending. Thus, as shown in FIGS. 12 and 13, the lead 29 inserted in the outer case 28 is used.
a, 29b, 29c, through the opening 37 of the outer case 28, the light source 32a such as a light emitting diode chip.
After the die 32b is die-bonded and wire-bonded, a transparent resin 33 is formed in the space between the opening 37 of the outer case 28 and the upper and lower light reflecting walls 34, and the light source 32 is placed in the transparent resin 33.
a and 32b are sealed, and the light emitting module 25 is assembled.

The light emitting module 25 has a plurality of light sources (two light sources 32a, 32 in the figure).
b is shown, but three or more may be used). This is to increase the amount of light by increasing the number of light sources.
Further, in the case of a color light source, it is for integrating the light emitting diodes of three colors of red (R), green (G), and blue (B) into one light emitting module 25.

On the light incident surface 24 of the light guide plate 22, coupling shafts 38 protrude from both sides of the concave portion 27, and couplings for inserting the coupling shafts 38 into both sides of the light emitting module 25. A hole 39 is drilled. Then, as shown in FIG. 10, the coupling shaft 38 of the light guide plate 22 is inserted into the coupling hole 39 of the light emitting module 25, and the light reflecting wall 34 of the light emitting module 25 is
The light emitting module 25 can be easily fixed to the light incident surface 24 of the light guide plate 22 by applying heat to the tip of the coupling shaft 38 and caulking the light emitting module 25.

Even in the surface light source device 36, the light source 32
The space 13 between the light guide plate 22 and the concave portion 27
Since it is covered by the light reflecting wall 34 that is stuck inside, the light does not leak in the vertical direction, and the light coupling efficiency between the light of the light source 32 and the light guide plate 22 is improved.

(Third Embodiment) FIGS. 14 and 15 are an exploded perspective view showing a surface light source device 41 according to still another embodiment of the present invention, and FIG. It is the top view which partly fractured. In the light emitting module 25 of this embodiment, the interval between the light reflecting walls 34 extending from the upper edge and the lower edge of the exterior case 28 formed of a white resin having a high light reflectance is equal to that of the light guide plate 22. The length of the light reflecting wall 34 is equal to the thickness of the light guide plate 2.
2 is larger than the depth of the recess 27. On the upper surface and the lower surface of the light guide plate 22, a coupling shaft 38 protrudes near the concave portion 27, and a coupling hole 39 having a cut is provided at a position corresponding to the light reflecting wall 34. I have.

Thus, the light emitting module 25 is pushed into the light guide plate 22 so as to sandwich the light guide plate 22 between the light reflecting walls 34 of the light emitting module 25, and the coupling shaft 3 of the light guide plate 22 is connected.
The light emitting module 25 is attached to the light guide plate 22 with one touch as shown in FIG. In such a structure, the light emitting module 25 can be easily positioned in the vertical direction with respect to the light guide plate 22 by the light reflecting wall 34, and is mounted at a predetermined position by the coupling shaft 38 and the coupling hole 39, so that assembly is easy. And the assembling accuracy is improved.

Thus, the light emitting module 25 is connected to the light guide plate 22.
In a state where the light source 32 is attached to the light source 32, as shown in FIG.
The light R emitted from the light source 32 is transmitted to the outer case 2 because the space 13 between the
The light guide plate 22 is confined in a space surrounded by the light reflection wall 8 and is extracted only to the light incident surface 24 of the light guide plate 22. Therefore, according to such an embodiment, the optical coupling efficiency between the light source 32 and the light guide plate 22 can be increased. In particular, if the light reflecting wall 34 is superimposed on the light guide plate 22 as in this embodiment, even if there is an error in mounting the light emitting module 25, a gap is generated between the light reflecting wall 34 and the concave portion 27, and There is no risk of leakage.

(Fourth Embodiment) FIG. 18 is a partially cutaway sectional view showing a surface light source device 42 according to still another embodiment of the present invention, and FIG. 19 is a perspective view of a light emitting module 25 thereof. In this embodiment, a step 43 is formed at the base of the inner surface of the light reflecting wall 34 of the light emitting module 25, and the step 43 is in contact with the light incident surface 24 of the light guide plate 22. Therefore, as shown in FIG. 18, the height of the light exit opening in the light emitting module 25 is smaller than the thickness of the light guide plate 22 due to the step portion 43, and the light emitting angle of the light from the light emitting module 25 is reduced. The optical coupling efficiency between the light guide plate 32 and the light guide plate 22 can be further increased.

(Fifth Embodiment) FIG. 20 is a perspective view showing a light emitting module 25 used in a surface light source device according to still another embodiment of the present invention. In this embodiment, the step 43 provided on the inner surface of the light reflecting wall 34 of the light emitting module 25 is formed in a substantially arc shape so as to match the edge of the concave portion 27 of the light guide plate 22. Therefore, the light emission opening of the light from the light source 32 can be narrowed, and the positioning of the light emitting module 25 can be performed more accurately. That is,
The upper and lower surfaces of the light guide plate 22 are sandwiched between the light reflecting walls 34 to position the light emitting module 25 in the vertical direction.
Can be positioned in the left-right direction and the front-rear direction.

(Sixth Embodiment) FIG. 21 is a partially broken sectional view showing a surface light source device 45 according to still another embodiment of the present invention. In this embodiment, the light guide plate 22
In the light emitting surface 23, the end on the light incident surface 24 side is cut by the thickness of the light reflecting wall 34 of the light emitting module 25 to form a step portion 44. Therefore, when the light emitting module 25 is attached to the end of the light guide plate 22, the light exit surface 2
On the third side, the light reflecting wall 34 of the light emitting module 25 fits into the step portion 44, and the surface of the light guide plate 22 and the surface of the light emitting module 25 are flush with each other, so that no step is generated. Therefore, when the liquid crystal display panel 46, the diffusion sheet, and the like are placed on the light emitting surface 23 side, the liquid crystal display panel 46 and the like can be placed stably.

(Seventh Embodiment) FIGS. 22 and 23 are an exploded perspective view and a partially broken enlarged perspective view showing a surface light source device 51 according to still another embodiment of the present invention. In this embodiment, the light emitting module 25 is disposed so as to face the concave portion 27 formed on the light incident surface 24 of the light guide plate 22, and the light emitting module 25 is disposed between the light emitting surface 23 of the light guide plate 22 and the upper surface of the light emitting module 25. By applying a reflective tape 52 between the side of the light guide plate 22 opposite to the light exit surface 23 and the lower surface of the light emitting module 25, the space 13 between the light source 32 and the recess 27 has the light exit surface 23 side and the same. It blocks the other side. The reflective tape 52 preferably has a high light reflectivity, and for example, a metallic tape such as an aluminum tape or a white tape with a high reflectivity may be used.

Thus, even in this embodiment, the light exit surface 2 of the space 13 between the light source 32 and the outer case 28 is provided.
Since the third side and the opposite side are closed by the reflective tape 52, the light emitted upward or downward from the light source 32 is reflected by the reflective tape 52, The light enters the light guide plate 22 from 27. Therefore, even in such an embodiment, the optical coupling efficiency between the light source 32 and the light guide plate 22 can be increased.

As shown in FIG. 24, the light emitting module 25 is surrounded by an outer case 28 made of a light-reflective white resin on the back, top, bottom, left and right of the light source 32. The light emitting module 25 and the light guide plate 22
The light leaks obliquely up and down from the space with the concave portion 27 of FIG. Therefore, in this embodiment, the reflection tapes 52 are attached between the upper and lower surfaces of the light guide plate 22 and the upper and lower surfaces of the light emitting module 25 as means for closing the space. At this time, as shown in FIG. 24, the inner dimension between the upper and lower wall surfaces of the outer case 28 is made smaller than the thickness of the light guide plate 22, and the outer surfaces of the upper and lower wall surfaces of the outer case 28 are placed between the upper and lower surfaces of the light guide plate 22. The outer case 28 of the light-emitting module 25 should be substantially flat.
The reflection tape 52 can be easily applied between the light guide plate 22 and the light guide plate 22.

Further, in this embodiment, the light emitting module 25 can be fixed at the same time by attaching the reflection tape 52 between the light guide plate 22 and the light emitting module 25. Therefore, in this embodiment, the optical coupling efficiency can be improved by simple means having high versatility.

(Eighth Embodiment) FIG. 25 is a perspective view showing a surface light source device 53 according to still another embodiment of the present invention. In this embodiment, for example, the light emitting module 25 as shown in FIG. 9 is arranged in the concave portion 27 of the light guide plate 22, and the reflection tape 52 is continuously provided over the plurality of light emitting modules 25.
Is affixed. Thus, one reflection tape 52
Is attached to the plurality of light emitting modules 25, the simplicity is further improved.

Further, even when the light reflecting wall 34 corresponding to the concave portion 27 of the light guide plate 22 extends from the outer case 28 as in the light emitting module 25 used in this embodiment, If the light reflecting wall 34 and the concave portion 27 of the light guide plate 22 do not completely match, light leaks up and down from the gap between the light reflecting wall 34 and the concave portion 27. Therefore, even when the light emitting module 25 has the light reflecting wall 34 that matches the concave portion 27, as in this embodiment, the upper and lower surfaces are closed so as to close the gap between the light emitting module 25 and the light guide plate 22. It is preferable that a reflective tape 52 is attached to the surface. Again,
The inside of the light reflecting wall 34 of the light emitting module 25
And the outer surface of the light reflecting wall 34 is
There is almost no step between the upper and lower surfaces of the light emitting module 2, and the reflection tape 52 can be easily applied between the light reflecting wall 34 of the light emitting module 25 and the light guide plate 22.

In each of the above embodiments, a case has been described in which the light emitting surface 23 of the light guide plate 22 and the opposite side have a light reflecting member of the same configuration. However, the light emitting surface 23 side and the opposite side have the same light reflecting member. The structure may be different. For example, on the light emitting surface 23 side, the structure is such that it fits into the concave portion 27 as shown in FIG. 5, and on the opposite side, the light guide plate 2 as shown in FIG.
2 may be superimposed.

(Liquid Crystal Display) FIG. 26 is an exploded perspective view showing a liquid crystal display 81 using the surface light source device 80 according to the present invention. A diffuse reflection sheet 82 is disposed on the front surface of the surface light source device 80, and a liquid crystal display panel 83 is disposed on the front surface. The liquid crystal display panel 83 includes a transparent electrode and a TF.
Two liquid crystal substrates (glass substrate, film substrate) 84 on which T, color filters, black matrix, etc. are formed,
A liquid crystal material is sealed between the liquid crystal substrates 85, and polarizing plates 86 are provided on both outer surfaces of the liquid crystal substrates 84 and 85.

According to such a liquid crystal display device 81, the surface light source device 80 having a high light coupling efficiency between the light source 32 and the light guide plate 22 and a high luminance can be used. Can be enhanced.

(Electronic Device Equipped with Liquid Crystal Display Device) The liquid crystal display device according to the present invention is a wireless information transmission device such as a mobile phone or a low-power radio device, a portable personal computer, an information processing device such as an electronic organizer or a calculator. It is preferable to use it for devices and the like. FIG. 27 is a perspective view showing a mobile phone 89 provided with a liquid crystal display device 81 as shown in FIG. 26 for display according to the present invention, for example, and FIG. 28 is a functional block diagram thereof. A button switch 90 such as a numeric keypad for dial input is provided on the front of the mobile phone 89, a liquid crystal display device 81 is provided above the switch 90, and an antenna 91 is provided on the upper surface. When a dial or the like is input from the button switch 90, the input dial information or the like is transmitted from the antenna 91 to the base station of the telephone company through the transmission circuit 92. On the other hand, the input dial information and the like are sent to the liquid crystal drive circuit 93, and the liquid crystal display device 81 is driven by the liquid crystal drive circuit 93, and the dial information and the like are displayed on the liquid crystal display device 81.

FIG. 29 is a diagram showing an example of FIG.
6. A portable information terminal 9 such as an electronic organizer or a portable personal computer having a liquid crystal display device 81 as shown in FIG.
4 is a perspective view showing FIG. 4, and FIG. 30 is a functional block diagram thereof.
When the cover 95 is opened, the portable information terminal 94 includes a key input section 96 and a liquid crystal display device 81. Inside the portable information terminal 94, a liquid crystal driving circuit 93, an arithmetic processing circuit 97, and the like are provided.
Thus, for example, when a ten key, a kana key, or the like is input from the key input unit 96, the input information is sent to the liquid crystal drive circuit 93 and displayed on the liquid crystal display device 81. Next, when a control key such as a calculation key is pressed, predetermined processing and calculation are executed in the calculation processing circuit 97, and the result is sent to the liquid crystal drive circuit 93 and displayed on the liquid crystal display device 81.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a conventional surface light source device.

FIGS. 2A and 2B are a perspective view and a sectional view showing a light source used in the surface light source device of the above.

FIG. 3 is an operation explanatory view of the above surface light source device.

FIG. 4 is a diagram illustrating a problem of the surface light source device of the above.

FIG. 5 is a perspective view of a surface light source device according to an embodiment of the present invention.

FIG. 6 is an enlarged exploded perspective view of the surface light source device according to the first embodiment with a part cut away.

FIG. 7 is an operation explanatory view of the surface light source device of the above.

FIG. 8 is an operation explanatory view of the above surface light source device.

FIG. 9 is a partially broken perspective view showing a surface light source device according to another embodiment of the present invention.

FIG. 10 is an exploded perspective view showing a surface light source device according to still another embodiment of the present invention, with a part cut away.

FIG. 11 is a partially broken plan view of the surface light source device.

FIG. 12 is a perspective view showing a light emitting module used in the above surface light source device.

FIG. 13 is a horizontal sectional view of the light emitting module of the above.

FIG. 14 is an exploded perspective view showing a surface light source device according to still another embodiment of the present invention, with a part cut away.

FIG. 15 is a partially broken perspective view of the surface light source device.

FIG. 16 is a partially broken plan view of the surface light source device.

FIG. 17 is an operation explanatory view of the surface light source device of the above.

FIG. 18 is a partially broken sectional view showing a surface light source device according to still another embodiment of the present invention.

FIG. 19 is a perspective view showing a light emitting module used in the above surface light source device.

FIG. 20 is a perspective view showing a light emitting module used in a surface light source device according to still another embodiment of the present invention.

FIG. 21 is a partially broken sectional view showing a surface light source device according to still another embodiment of the present invention.

FIG. 22 is an exploded perspective view showing a surface light source device according to still another embodiment of the present invention.

FIG. 23 is a partially broken perspective view of the surface light source device.

FIG. 24 is a partially broken sectional view of the surface light source device of the above.

FIG. 25 is a perspective view showing a surface light source device according to still another embodiment of the present invention.

FIG. 26 is an exploded perspective view of a liquid crystal display device using the surface light source device of the present invention.

FIG. 27 is a perspective view showing a mobile phone provided with a liquid crystal display device according to the present invention for a display.

FIG. 28 is a block diagram showing a configuration for driving a liquid crystal display device in the above mobile phone.

FIG. 29 is a perspective view showing a portable information terminal such as an electronic organizer provided with a liquid crystal display device according to the present invention for a display.

FIG. 30 is a block diagram showing a configuration for driving a liquid crystal display device in the portable information terminal of the above.

[Explanation of symbols]

 Reference Signs List 22 light guide plate 23 light emitting surface 24 light incident surface 25 light emitting module 27 concave portion 28 outer case 32 light source 34 light reflecting wall 38 coupling shaft 39 coupling hole 43 step 52 reflection tape

Claims (8)

[Claims] 1. A surface light source device for guiding light emitted from a light source from a light incident surface into a light guide plate, confining the light inside the light guide plate, and extracting the light from the light exit surface of the light guide plate to the outside. A surface light source, wherein a concave portion is formed, the light source is arranged so as to face the concave portion, and the light emitting surface side and the opposite surface side of the space between the light source and the concave portion are covered with a light reflective member. apparatus. 2. The surface light source device according to claim 1, wherein the light-reflective member is a part of an exterior member surrounding the light source, and is fitted in the recess. 3. The light-reflective member is a part of an exterior member surrounding the light source, and covers the recess so as to overlap a surface of the light guide plate. 2. The surface light source device according to 1. 4. The light-reflecting member according to claim 3, wherein a step portion is formed on an inner surface of the light-reflective member, and the step portion is opposed to an end surface of the light guide plate on a light incident surface side. Surface light source device. 5. A light-reflecting member is formed by forming a step on the light-emitting surface of the light-guiding plate such that the end of the light-guiding plate has a small thickness, and placing the light-reflecting member in the step. The surface light source device according to claim 3, wherein the surface of the light guide plate is substantially flush with the surface of the light guide plate. 6. The surface light source device according to claim 1, wherein the light-reflective member is a reflection tape stuck between an exterior member surrounding the light source and the light guide plate. 7. The reflection tape is continuously applied over the exterior members of the plurality of light sources.
A surface light source device according to claim 1. 8. The light guide plate according to claim 2, wherein a coupling member for coupling the light guide plate and the exterior member of the light source is provided on at least one of the light guide plate and the exterior member of the light source. Surface light source device.