JP4021340B2 - Lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
[0002]
The present invention relates to a lighting device, and particularly relates to a large-sized lighting device that requires high luminance.
[0003]
In recent years, display units have been used in large quantities in word processors, personal computers, and the like due to expansion of display capacity or improvement in characteristics. Furthermore, a thin and light display unit having a large screen size for a workstation from a notebook is required, and a high-luminance and high-efficiency lighting device is desired for colorization.
[Prior art]
[0004]
Conventionally, the edge-light type backlight used in the liquid crystal display device is made to make light incident from the side surface of the light guide plate, and the internal propagation light by total reflection is totally reflected by the light guide plate and white ink etc. whose central part is inclined. Was broken and emitted to the light emitting surface side.
[0005]
FIG. 7 is an explanatory diagram of a conventional edge light type illumination device.
[0006]
In the figure, 81 is a fluorescent tube serving as a light source, 82 is a light guide plate made of transparent resin, 82a is an incident surface of the light guide plate 82, 82b is a back surface of the light guide plate 82 on which a diffuse reflection pattern is printed, and 82c is a light guide plate 82. , 83 is a reflecting sheet, 84 is a light emitting surface, 85 is a reflecting mirror provided so as to surround the fluorescent tube 81, 86 is a linear prism, 87 is a diffusion sheet, 88 is internally propagated light, and 89 is emitted light. There is a lighting device 90 comprising them.
[0007]
As shown in the figure, in the conventional edge light type backlight, a fluorescent tube 81 surrounded by a reflecting mirror 85 is arranged so that the emitted light is incident from an incident surface 82 a of the light guide plate 82, and the light guide plate 82. The emission surface 82c is inclined from both ends toward the central portion so that the thickness thereof becomes thinner toward the central portion. Then, a diffuse reflection pattern with white ink or the like is provided on the back surface 82b of the light guide plate 82 so as to increase the printing area as the distance from the fluorescent tube 81 increases, and the diffuse reflection pattern is scattered on the back surface of the back surface 82b. A reflection sheet 83 for effectively emitting light rays is disposed. Further, a linear prism 86 for collecting the outgoing light 89 in the normal direction is provided on the light emitting surface 84 above the light guide plate 82, and the diffuse reflection pattern on the back surface 82 b is visually recognized on the outgoing direction side of the linear prism 86. A diffusion sheet 87 is arranged so as not to be formed, and an edge light type illumination device 90 is configured.
[0008]
In this conventional edge light type illumination device 90, the diffused light emitted from the fluorescent tube 81 enters from the incident surface 82a of the light guide plate 82, and propagates through the light guide plate 82 while satisfying the total reflection condition. Since the outgoing surface 82c of the light guide plate 82 is inclined toward the central portion, the internal propagation light 88 becomes steeper by the inclination angle θ of the outgoing surface 82c every time it is totally reflected by the outgoing surface 82c, and the critical angle. If it becomes above, it will become the emitted light 89, and is radiate | emitted from the output surface 82c, On the other hand, the propagation light 88 which was totally reflected by the output surface 82c and reached the back surface 82b will be radiate | emitted from the light emission surface 84 because a total reflection condition collapse | crumbles by a diffuse reflection pattern. It is like that.
[Problems to be solved by the invention]
[0009]
The conventional edge light type illumination device does not emit all the light rays emitted from the fluorescent tube and diffusely reflected by the diffuse reflection pattern to the light emitting surface side, but part of the light is repeatedly propagated to the opposite fluorescent tube. The current situation is that light loss occurs due to collision. In order to reduce this phenomenon, an attempt has been made to improve the light guide plate by providing an inclination on the exit surface of the light guide plate and reducing the thickness of the light guide plate toward the center, but it is still insufficient and the light utilization rate is low. There was a problem.
[0010]
In order to effectively improve the luminance in the normal direction, a linear prism plate is arranged between the light guide plate and the diffuser plate. The prism pitch of the linear prism plate and the matrix display panel If the pitch between the electrodes is not optimum, interference occurs. Therefore, a diffusion plate having a high diffusion degree is used, or an optimum pitch is set for each model to reduce the occurrence of interference. However, when the diffusivity is increased, the luminance in the normal direction decreases, and when a linear prism mold suitable for each model is manufactured, the cost increases.
[0011]
Accordingly, an object of the present invention is to realize a thin and lightweight high-efficiency lighting device having high luminance and uniform luminance distribution.
[Means for Solving the Problems]
[0012]
The invention of claim 1 comprises a plurality of unit units including a light source (71 ″) and a light guide plate (72 ″),
The light guide plate (72 ″) includes an incident surface (72a ″) on which a light beam emitted from the light source is incident, a reflective surface (73 ″) that reflects the incident light beam, and an output surface (72 ”) that emits the incident light beam. 72b ") and a side surface facing the reflecting surface,
The adjacent unit units are stacked obliquely,
The reflection surface of the first unit unit and the side surface of the second unit unit adjacent to the first unit unit are arranged adjacent to each other.
[0013]
FIG. 1 is a block diagram showing the principle related to the present invention.
[0014]
In the figure, 1 is a light source, 2 is a light guide plate, 2a is an entrance surface of the light guide plate 2, 2b is a back surface of the light guide plate 2, 2c is an exit surface of the light guide plate 2, 3 is a reflection surface, 3a is a reflection surface 3 A side wall surface facing the light source 1, 4 is a light emitting surface, and 5 is a space.
[0015]
As shown in the figure, the illuminating device according to the present invention includes a light source 1, a light guide plate 2 having a light incident surface 2 a on which light rays from the light source 1 are incident, and an output surface 2 c from which incident light rays are emitted, and a light guide plate. 2, the light guide plate 2 is disposed on the side of the light guide plate 2, and the light guide plate 2 is disposed on the side of the light guide plate 2. As the distance from the light source 1 is increased, the light exit surface 2c is formed so that the thickness of the light guide plate 2 is reduced, and the reflective side surface 3a that opposes the light source 1 with the light guide plate 2 of the light guide plate 2 and the reflective surface 3 interposed therebetween. A space portion 5 sandwiched between the reflecting surface 3 and the light emitting surface 4 is formed between the two.
[0016]
Furthermore, the exit surface 2c of the light guide plate 2 is composed of a plurality of continuous planes having different inclination angles with the back surface 2b, and the inclination angle of the plane on the tip side of the light guide plate 2 is larger than the inclination angle of the plane on the incident surface 2a side. It is characterized by that.
[0017]
Furthermore, the incident surface 2a of the light guide plate 2 is a diffusing surface provided with unevenness.
[0018]
Furthermore, the back surface 2b of the light guide plate 2 is a diffusing surface.
[0019]
Furthermore, the exit surface 2c of the light guide plate 2 is a diffusing surface.
[0020]
Further, a transparent diffusion sheet is disposed between the back surface 2b of the light guide plate 2 and the reflection surface 3.
[0021]
Furthermore, the reflecting surface 3 is an uneven surface.
[0022]
Further, at least one linear prism plate for converging outgoing light in the normal direction is provided on the light emitting side of the light emitting surface 4, and at least one of the linear prism plates emits light in the axial direction of the linear prism plate. The display device arranged on the surface 4 is arranged such that the relative position with respect to the direction of the matrix electrode pattern is not parallel or orthogonal.
[0023]
Further, as another aspect of the lighting device according to the present invention, the lighting device according to the present invention is composed of a plurality of unit units, and a plurality of light emitting surfaces 4 of each unit unit are arranged on the same plane. The unit units are arranged in a plane.
[0024]
Further, as yet another aspect of the lighting device according to the present invention, the lighting device according to the present invention is composed of a plurality of unit units, and a plurality of the unit unit reflecting surfaces 3 and light emitting surfaces 4 are adjacent to each other. These unit units are stacked, and the side wall surface 3a side of the unit unit is used as a light emitting surface.
[0025]
FIG. 2 is an explanatory view of the operation of the lighting device related to the present invention.
[0026]
In the figure, 1 is a light source, 2 is a light guide plate for propagating light from the light source, 2a is an incident surface of the light guide plate 2 on which light from the light source is incident, 2b is a back surface of the light guide plate 2, and 2c is a light guide plate 2. The exit surface from which the light propagating through the light guide plate 2 is emitted is formed so that the angle formed with the back surface b is θ so that the wall thickness decreases as the distance from the light source 1 increases, 3 is the back surface 2b of the light guide plate 2 3a is a side wall surface of the reflective surface 3 facing the light source 1 with the light guide plate 2 interposed therebetween, and 4 is a light guide plate 2 that receives the light from the light source 1. A light emitting surface that emits light through 5, 5 is a space where the light emitting surface 2 c, the reflecting surface 3, the side wall surface 3 a, and the light emitting surface 4 are sandwiched, 6 surrounds the light source 1, and the light from the light source 1 enters the incident surface 2 a of the light guide plate 2. Reflecting mirror 7 reflecting in the direction, 7 is the internally propagating light that is incident from the incident surface 2a and propagates inside the light guide plate 2, 8 is A emission light emitted from the emitting surface 2c After propagated inside the optical plate, 10 denotes an illumination device composed of these.
[0027]
As shown in the drawing, in the illumination device 10 according to the present invention, the light emitted from the light source 1 is reflected by the reflecting mirror 6, and the light that repeats multiple reflections with the light source 1 and the direct light are combined to form the light guide plate 2. Incident from the input surface 2a.
[0028]
Here, the light incident on the light guide plate 2 is incident at about ± 42 ° with respect to the normal of the incident surface according to Snell's law, and the surface of the light guide plate is perpendicular to the incident surface. The angle of the light beam reaching the angle is about ± 48 ° or more with respect to the normal of the surface of the light guide plate, and is totally reflected and propagates inside the light guide plate. Therefore, when the surface of the light guide plate is a plane perpendicular to the incident surface, all the propagating light is emitted from the end surface facing the light source of the light guide plate.
[0029]
However, the light guide plate 2 of the illuminating device 10 according to the present invention is formed such that the exit surface 2c is inclined with the angle formed with the back surface 2b being θ, so that the thickness of the light guide plate 2 decreases as the distance from the light source 1 increases. Therefore, the propagating light 7 incident from the incident surface 2a is steep at an angle of the inclination angle θ with respect to the output surface 2c every time it is totally reflected by the output surface 2c. While the reflection is repeated, a part of the propagation light 7 is emitted from the emission surface 2 c as the emission light 8 toward the light emitting surface 4, and a part of the propagation light 7 is repeatedly propagated as the propagation light 7. Further, the propagating light 7 is partially emitted from the back surface 2b, but is reflected toward the light emitting surface 4 by the reflecting surface 3 facing the back surface 2b.
[0030]
Moreover, the outgoing light 8 emitted from the front end side of the light guide plate 2 reaches the light emitting surface 4 directly, or the light emitted from the light emitting surface 4 after being reflected by the side wall surface 3a of the reflecting surface 3 without reaching directly. There is.
[0031]
Here, when the reflective side surface is provided adjacent to the end of the light guide plate away from the light source, the amount of light reflected by the reflective side surface increases, leading to an increase in the light loss rate, A difference in luminance distribution occurs because the light beam that directly reaches the light-emitting surface after being emitted from the light plate and the light beam that reaches the light-emitting surface after being reflected by the reflecting side surface overlap at a portion slightly inside the edge of the light-emitting surface. .
[0032]
However, in the illuminating device 10 according to the present invention, a gap is provided between the front end portion of the light guide plate 2 and the side wall surface 3a, and the light guide plate 2 and the side wall surface 3a are sandwiched between the reflecting surface 3 and the light emitting surface 4. By arranging the space portion 5, most of the emitted light 8 emitted from the emission surface 2 c can be emitted directly in the direction of the emission surface 4, the luminance distribution is made uniform, the light loss is reduced, and high efficiency is achieved.
[0033]
Figure 3 is a diagram showing another illumination equipment relating to the present invention, showing a luminance distribution of part (a) shows the cross-sectional view, (b) drawing the illumination device.
[0034]
In FIG. 9A, 11 is a fluorescent tube, 12 is a light guide plate, 12a is an incident surface of the light guide plate 12, 12b is a back surface of the light guide plate 12, 12c ′ is a first emission surface of the light guide plate 12, and 12c ″ is The second exit surface, 13 is a reflecting surface, 14 is a light emitting surface, 15 is a space portion, 16 is a reflecting mirror, and 20 is an illuminating device composed of them.
[0035]
As shown in FIG. 6A, the illumination device has an incident surface 12a and a light source 11 on the light emission side of the fluorescent tube 11 surrounded by a reflecting mirror 16 in a semicircular shape in order to collect emitted light in one direction. The light guide plate 12 is disposed so as to face each other. The light guide plate 12 has an emission surface inclined so that the thickness thereof becomes thinner as the distance from the light source 11 increases, and the emission surface is in contact with the first emission surface 12c ′ having an angle θ1 with respect to the back surface 12b on the light source 11 side. , The second exit surface 12c ″ having an angle θ2 with respect to the back surface 12b on the distal end side, θ2 is larger than θ1, and the boundary between the first exit surface 12c ′ and the second exit surface 12c ″ is It is chamfered and curved. Further, the reflective surface 13 is opposed to the back surface 12 b of the light guide plate 12, the side wall surface 13 a of the reflective surface 13 is disposed on the side facing the light source 11, and the light emitting surface 14 is provided on the side facing the reflective surface 13. Yes. A space is provided between the front end of the light guide plate 12 and the side wall surface 13a, and the space surrounded by the emission surfaces 12c ′ and 12c ″ of the light guide plate 12, the reflection surface 13, the side wall surface 13a, and the light emitting surface 14. A portion 15 is provided.
[0036]
The shape of the light guide plate 12 is set such that the inclination angle θ1 of the first emission surface 12c ′ on the light source 11 side with respect to the back surface 12b is different from the inclination angle θ2 of the second emission surface 12c ″ on the tip side with respect to the back surface 12b. By forming the angle θ2 to be larger than θ1, the emitted light can be appropriately dispersed and emitted without being concentrated on the tip portion, so that the light utilization rate is improved and the luminance distribution at the end portion of the light emitting surface 14 is improved. In addition, the processing of the light guide plate 12 during molding is easier than that with a sharp tip, and the yield can be improved because damage to the tip is reduced and handling is easy.
[0037]
FIG. 7B is a diagram showing a luminance distribution when the angle θ2 is constant and the angle θ1 is changed (assuming θ2> θ1) in the lighting device, and a solid line 401 indicates a case where the angle θ1 is small. A broken line 402 indicates a case where the angle θ1 is large.
[0038]
As shown in the figure, when the angle θ1 is small, the amount of light emitted from the first emission surface 12c ′ is small and propagates to the front end side of the light guide plate 12, so that the amount of light emitted from the front end side is large and the luminance is high. However, when the angle θ1 is large, the amount of light emitted from the first emission surface 12c ′ increases, while the amount of light emitted from the second emission surface 12c ″ decreases, so that the luminance distribution becomes uniform. However, the luminance distribution on the tip side increases or decreases in a similar manner in proportion to the angle θ1.
[0039]
The reflecting surface 13 may be a diffusing surface, a mirror surface, or the like. If the reflecting surface 13 is a diffusing surface, the light emitted from the back surface 12b of the light guide plate 12 is diffused, so the amount of light emitted in the vicinity of the light source 11 And the luminance distribution can be made uniform.
[0040]
FIG. 4 is a diagram showing a first embodiment of the lighting device according to the present invention, and is a partial sectional view of the lighting device.
[0041]
In the figure, 71 is a fluorescent tube, 72 is a light guide plate, 72a is an entrance surface of the light guide plate 72, 72b is an exit surface of the light guide plate 72, 73 is a reflection surface, 74 is a reflection mirror, 75 is a diffusion sheet, 80 Is a lighting device composed of them.
[0042]
As shown in the figure, the lighting apparatus 80 of this embodiment, the upright position a plurality of basic units a lighting apparatus shown in FIG. 3 as a unitary unit, the side and the reflection surface 73 of the light guide plate 72 in the unit It arrange | positions so that it may adjoin and makes the light emission surface the surface facing the fluorescent tube 71. FIG. Further, the angle θ formed by the light exit surface 72b of the light guide plate 72 and the reflection surface 73 is 30 °, and the light guide plate 72 is made of acrylic resin. A diffusion sheet 75 is arranged on the light emitting surface side so that the luminance distribution is uniform and the reflecting surface 73 is not visible. Of the emitted light emitted from the emitting surface 72b of the light guide plate 72 of one unit unit, Except for those that directly reach the diffusion sheet 75, the light is reflected by the reflection surface 73 of the adjacent unit unit and proceeds to the diffusion sheet 75.
[0043]
The illuminating device 80 shown in the present embodiment is suitable for a large-sized illuminating device that requires high luminance, and a plurality of unit units are arranged vertically by using the illuminating device as shown in FIG. 3 as a unit unit. Thus, a high-luminance lighting device having a uniform luminance distribution, a high light beam directivity, and a high light beam utilization rate can be obtained.
[0044]
FIG. 5 is a view showing a second embodiment of the lighting device according to the present invention, and is a partial sectional view of the lighting device.
[0045]
In the figure, 71 ′ is a fluorescent tube, 72 ′ is a light guide plate, 72a ′ is an incident surface of the light guide plate 72 ′, 72b ′ is an exit surface of the light guide plate 72 ′, 73 ′ is a reflection surface, 74 ′ is a reflection mirror, 75 'is a diffusion sheet, and 80' is an illumination device composed of them.
[0046]
As shown in the figure, the illumination device 80 'of this embodiment the first light guide plate 72 as in Example' is formed so that the cross section shape of the different shapes of the light guide plate 72 'is substantially isosceles triangle Two exit surfaces 72b 'are provided with the apex angle inserted. The apex angle θ is 30 ° as in the sixth embodiment.
[0047]
The illuminating device 80 ′ shown in the present embodiment can be a high-luminance illuminating device with improved light beam directivity and higher light utilization rate than the first embodiment.
[0048]
FIG. 6 is a view showing a third embodiment of the lighting device according to the present invention, and is a partial sectional view of the lighting device.
[0049]
In the figure, 71 "is a fluorescent tube, 72" is a light guide plate, 72a "is an entrance surface of the light guide plate 72", 72b "is an exit surface of the light guide plate 72", 73 "is a reflection surface, 74" is a reflection mirror, Reference numeral 75 "denotes a diffusion sheet, and reference numeral 80" denotes an illuminating device constituted by them.
[0050]
As shown in the figure, the lighting device 80 "of this embodiment is different from the first and second embodiments in the arrangement method of the unit units, and the side surface of the light guide plate 72" and the reflecting surface 73 "in the unit are adjacent to each other. Thus, the unit units are obliquely stacked, and the light exit surface 72b ″ of the light guide plate 72 ″ serves as the light emitting surface. The apex angle θ is 30 ° as in the sixth embodiment.
[0051]
The lighting device 80 ″ shown in the present embodiment can be made thinner than the first and second embodiments, and can be a thin lighting device with high light utilization rate and high brightness.
【The invention's effect】
[0052]
As described above, according to the present invention, a plurality of unit units including a light source and a light guide plate are provided, and the light guide plate has an incident surface on which light emitted from the light source is incident and a reflection that reflects the incident light. Including a surface, an exit surface that emits an incident light beam, and a side surface that opposes the reflection surface, and the adjacent unit units are stacked obliquely, the reflection surface of the first unit unit, and the first unit unit that said side surface of the second unit unit adjacent to the first unit unit, because the are made of a structure that is positioned adjacent the optical line utilization to realize the thin illuminating device with high high brightness I can do it.
[Brief description of the drawings]
FIG. 1 is a principle configuration diagram of an illumination device related to the present invention.
FIG. 2 is an operation explanatory diagram of a lighting device related to the present invention.
3 is a diagram showing another illumination device associated with the onset bright.
FIG. 4 is a diagram showing a first embodiment of a lighting device according to the present invention.
FIG. 5 is a diagram showing a second embodiment of the illumination device according to the present invention.
FIG. 6 is a diagram showing a third embodiment of the illumination device according to the present invention.
FIG. 7 is a diagram showing a conventional lighting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light source 2 Light-guide plate 2a Incidence surface 2b Back surface 2c Output surface 3 Reflection surface 3a Side wall surface 4 Light emission surface 5 Space part 6 Reflector 7 Propagation light 8 Output light 10 Illuminating device 11, 71, 71 ', 71 "Fluorescent tube 12, 72, 72 ', 72 "Light guide plate 12a, 72a, 72a', 72a" Light guide plate entrance surface 12b, 72b Light guide plate back surface 12c 'Light guide plate first light exit surface 12c "Light guide plate second light exit surface 13, 73, 73 ′, 73 ″ Reflecting surface 14 Light emitting surface 15 Space portion 16 Reflecting mirror 20 Illuminating device 72b ′ 72b ″ Output surface of light guide plate 74, 74 ′, 74 ″ Reflecting mirror 75, 75 ′, 75 ″ Diffusion sheet 80, 80 ', 80 "lighting equipment

Claims (1)

A plurality of unit units including a light source and a light guide plate are provided,
The light guide plate includes an incident surface on which a light beam emitted from the light source is incident, a reflection surface that reflects the incident light beam, an emission surface that emits the incident light beam, and a side surface facing the reflection surface,
The adjacent unit units are stacked obliquely,
The lighting device in which the reflection surface of the first unit unit and the side surface of the second unit unit adjacent to the first unit unit are arranged adjacent to each other .

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