JP2000047038A - Back light device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the efficiency of the light utilization efficiency of a back light device and a display device. SOLUTION: This back light device generates back light by a light source 1, a means for introducing the light radiated from this light source 1 onto a two-dimensional plane and a means for radiating the light introduced onto this two-dimensional plane in the normal direction of the two-dimensional plane. The back light device has a plurality of optical fibers 3 consisting of cores and clads lined up in parallel on the two-dimensional plane, a coupling means 8 for coupling the light radiated from the light source 1 to the one-side ends of the respective optical fibers 3 and a mirror 2 disposed in correspondence to the peripheral surfaces of the optical fibers 3 exclusive of the surfaces to radiate the light toward the side on the two-dimensional plane and part or the whole of the other-side end faces. The back light is generated by the light 4 leaking from the outside surface of the clads of the respective optical fibers 3. The varying magnitude of the intensity of the light 4 radiated from the clad surfaces of the optical fibers 3 may be changed by changing the diameters of the cores, the thicknesses of the cores and the refractive indices of the cores and the clads.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device for a non-light emitting display device and a display device using the same.

[0002]

2. Description of the Related Art A backlight device is used as a monitor for a portable terminal such as a notebook computer together with a liquid crystal panel which is a non-light emitting display device. It is required to be shaped, lightweight, and highly efficient.

[0003] A display in which a backlight device and a liquid crystal panel are combined is also used as a space-saving television for home use, and a large screen is required.

FIG. 19 shows a non-light emitting type display device (liquid crystal).
Of the related art backlight device [Liquid Crystal Device Handbook, Nikkan Kogyo Shimbun, p. 276-279, 1989.9]. A small fluorescent lamp 70 as a light source, a light guide plate 71,
The optical system includes a reflection plate 72 and an optical system including a reflection sheet 73. Light 74 emitted from the small fluorescent lamp 70
Is reflected by the reflection plate 72 and enters the light guide plate 71.
The light 74 in the light guide plate 71 propagates by total reflection. When the light 74 hits a printed white dot called a diffusion dot 75 on the bottom surface of the light guide plate 71 in the propagation process, diffuse reflection occurs. Is emitted. Light guide plate 7
The side surface and the bottom surface of the light guide plate 1 are covered with a reflection sheet 73, and function to return the light 74 that has exited the light guide plate 71 without hitting the diffusion dots 75 into the light guide plate 71.

In this apparatus, a light source (small fluorescent lamp 7) is used.
0) is guided by a light guide plate 71 on a two-dimensional plane, and the light 74 guided on the two-dimensional plane is radiated from the diffusion dots 75 in the normal direction of the two-dimensional plane. The backlight is generated by the configuration of the means for causing the backlight.

On the other hand, Japanese Patent Application Laid-Open No. 7-301714 discloses a technique for providing a thin, low power consumption surface emitting device at low cost. This surface light emitting device is a thin and transmissive display backlight using an LCD or the like or a surface light source that can be used for illumination or decoration. It emits monochromatic light, and has a structure including a multicolor or monochromatic light source (eg, an LED), and an exterior plate having an integrated structure including a light branching path, a light guide path, and a light emitting section. And a light scattering film on the front surface of the light emitting surface of the exterior plate.

[0007]

[Problems to be Solved by the Invention] "The Latest in Liquid Crystal Displays" (Edited by Young Researchers Group for Liquid Crystal, Sigma Publishing, Oct. 1, 1996)
According to (0), the aperture ratio of the TN type TFT-LCD is 60% or less, and the aperture ratio decreases as the definition becomes higher. In other words, the aperture ratio of light from the conventional backlight device becomes 4%.
It means that 0% or more is not used.

A conventional color TN type TFT-LCD
Uses R, G, and B color filters for colorization. According to the above-mentioned document (the leading edge of liquid crystal displays), the light transmittance of the filters is about 25%.
This also means that 75% of the light is lost.

On the other hand, in the conventional backlight device for a non-light emitting display device (liquid crystal), a fluorescent lamp having an outer diameter of several mm is arranged adjacent to an end of the light guide plate. However, there is a limit to the further reduction in thickness and weight. In addition, light is emitted only from the diffusion dots scattered on the surface of the light guide plate, resulting in a large loss of light used as a backlight, which limits the efficiency of light utilization and increases the screen size. .

Also, when the conventional surface emitting device is applied to a backlight device for a liquid crystal display, the aperture ratio becomes a problem. The waveguide has a homogeneous structure and is propagated by reflection / refraction with the outer plate. Furthermore, a structure in which light is distributed by a light distribution path when a light source is shared is proposed. In such a structure, the light distribution path requires a certain size, which leads to an increase in size. If the light distribution path is forcibly realized in a small size, there is a very serious problem that the distribution loss of light increases rapidly. that's all,
Since the problem of the aperture ratio, the propagation loss of the waveguide, and the distribution loss of the optical power in the optical distribution path occur, the power of the supplied light 10
0% utilization efficiency is not possible.

An object of the present invention is to provide a backlight device and a display device capable of achieving high efficiency of light use efficiency.

Another object of the present invention is to provide a backlight device and a display device which can achieve a large screen by increasing the efficiency of light utilization.

Another object of the present invention is to provide a thin and lightweight backlight device and display device.

Another object of the present invention is to provide a thin and lightweight backlight device having a high aperture ratio by avoiding light emission at portions other than the opening of the TFT-LCD. .

Another object of the present invention is to provide a backlight device that uses three light sources of R, G, and B to eliminate the necessity of a color filter of a TFT-LCD and to achieve high efficiency. .

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0017]

The following is a brief description of an outline of typical inventions disclosed in the present application.

(1) The present invention provides a means for guiding light from a light source on a two-dimensional plane and a means for uniformly emitting light in a direction normal to the two-dimensional plane, and the surface is not covered with a coating material. An optical fiber composed of a core and a clad is used. A plurality of optical fibers are arranged in parallel, a light source is arranged on one end side, and light emitted from the light source is transmitted from one end of the optical fiber into the core by a reflector (coupling means) having a reflecting mirror having an elliptical surface. Introduce. Each core guides the light on a two-dimensional plane, and the light emitted from the outer surface of the cladding constitutes a backlight. Mirrors are arranged on the lower side of the optical fiber and on the other end side of the optical fiber to effectively use light. The wiring of the TFT-LCD parallel to the optical fiber is laid between the optical fibers. In a wiring portion orthogonal to the optical fiber, light emission from the surface of the optical fiber is reduced to zero. Light is not radiated from a portion other than the radiation surface as the backlight device, and the light intensity distribution on the radiation surface is made uniform (uniform). A plurality of light sources can be connected to one optical fiber, and which of the plurality of light sources is used can be switched. A light source of three primary colors is prepared, and the light is emitted from an optical fiber by color coding periodically.

(2) In the configuration of the means (1), one or more of the following means are adopted and the setting conditions are selected.

(A) The magnitude of the intensity of light emitted from the cladding surface of the optical fiber depends on the diameter of the core constituting the optical fiber, the thickness of the cladding covering the core, and the difference in the refractive index between the core and the cladding. Is determined according to the structure in which one or more of the configurations are changed.

(B) The means for emitting light from the optical fiber is based on skew ray excitation.

(C) In the optical fiber, unevenness is provided on a boundary surface between the core and the clad or an outer surface of the clad or both.

(D) A scattering structure due to scattering substances and voids is scattered in the core of the optical fiber.

(E) A fluorescent substance is dispersed in the core of the optical fiber.

(F) A light emitting surface having a structure in which at least a part of the upper surface of the two-dimensional plane of the optical fiber is cut off is provided, and light is emitted only from the light emitting surface.

(G) By selecting one or more of the core diameter, cladding thickness, refractive index difference, unevenness, scattering material scattering, fluorescent material scattering, and light emitting surface position, and selecting the structure conditions. A backlight having a predetermined distribution is generated.

(H) By selecting one or more of the core diameter, clad thickness, refractive index difference, unevenness, scattering material scattering, fluorescent material scattering, and light emitting surface position, and selecting the structure conditions. A backlight having a uniform light intensity distribution is generated.

According to the means (1), (a) the optical fiber is a thin and long light guide, and is characterized in that it is formally flexible. Therefore, the light from the light source
By using an optical fiber as a means for guiding light on a two-dimensional plane and a means for uniformly emitting light on the two-dimensional plane, the degree of freedom between the light source and the surface that actually emits light, and the actual light It is possible to provide a backlight device having a degree of freedom of a radiation surface itself.

(B) Since the optical fiber itself is thinner and longer than a light guide plate made of an acrylic plate or the like used in a conventional backlight device, according to the present invention, it is possible to reduce the thickness, weight, and size of the screen. Become.

(C) When a display device is formed by using the backlight device, a display device for performing intensity modulation includes:
By not laying optical fibers in parallel wiring portions that do not contribute to display and not emitting light from orthogonal wiring portions, the proportion of the display light emitting area per light emitting area as a backlight device increases, and the present invention It is possible to increase the efficiency, which is the object of the invention.

(D) In the present invention, the periphery of a long light source is covered with a reflector, and a coupling portion for an optical fiber is provided in the cover of the reflector. Looking at an ideal cross section of this structure, the elliptical surface having the coupling portion between the light source and the optical fiber as two poles is arranged so as to be a reflector. Therefore, a distribution loss of the optical power unlike the optical distribution path does not occur.

(E) In the present invention, an optical fiber is used from the light source to the radiation section. Due to the structure of the core and cladding of the optical fiber, the loss of the light is as small as the transmission loss used for communication.

(F) According to the present invention, it is possible to provide a high-efficiency and low-power-consumption backlight device which is closer to 100% of the supplied light power than the conventional surface emitting device technology.

According to the above-mentioned means (2), it is possible to increase the radiation intensity of light to the upper side of the two-dimensional plane and to make the radiation state of the light a desired distribution. Therefore, it is possible to provide a backlight device having a uniform light distribution, and it is possible to have the same effect as the means (1).

[0035]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and a repeated description thereof will be omitted.

(Embodiment 1) FIG. 1 is a schematic diagram showing an outline of a backlight device according to an embodiment (Embodiment 1) of the present invention. FIG. 1A is a perspective view of the backlight device.
FIG. 1B is a schematic sectional view of the backlight device.

The backlight device of the first embodiment is similar to that of FIG.
As shown in (a) and (b), a columnar light source 1, an elliptical cylindrical reflector 2 disposed so as to surround a peripheral surface of the light source 1, and a light source along one side of the reflector 2. And a plurality of optical fibers 3 arranged side by side. For convenience of explanation, the extending direction of the optical fiber 3 is set to the X direction,
The extending direction of the light source 1 perpendicular to the above is defined as a Y direction, and the direction perpendicular to the XY plane is defined as a Z direction.

The reflecting plate 2 forms a reflecting mirror having an inner surface formed of an elliptical surface, and condenses the light 4 emitted from the light source 1 at one location. One end of each of the optical fibers 3 is located at the converging portion, and the light 4 is taken into the optical fiber 3. That is, the light source 1 is located at one focal point of the ellipse, and one end of the optical fiber 3 is located at the other focal point. Light source 1 and one end of optical fiber 3 and reflector 2
A coupling unit 8 (coupling means) is configured by these.

The optical fibers 3 are arranged in a line on one side of the reflection plate 2. The arranged plurality of optical fibers 3
The (optical fiber bundle) is located on a two-dimensional plane of the backlight device.

The light 4 from the light source 1 is collected by the reflector 2 and
The light enters from one end of the optical fiber 3. In this case, the light collection efficiency can be maintained at 60 to 70% or more as in the conventional backlight device.

Conventionally, an optical fiber used in the field of optical communication is not preferable because light emission from its surface leads to loss, but here, light emission is intentionally caused from the surface. The optical fiber thus configured is used.
As an optical fiber used for optical communication and the like, for example,
Silica glass optical fiber, multi-component glass optical fiber,
There are plastic optical fibers. For example, in the case of a silica glass-based optical fiber as an example, in the case of a single mode optical fiber, a core having a diameter of 8 μm or 10 μm is required.
It has a structure covered with a cladding having a diameter of 25 μm, and the refractive index n1 of the core is larger than the refractive index n2 of the cladding. Further, a multi-mode optical fiber having a core diameter of 50 μm is used.

In the present invention, the present invention can be applied to a fiber other than a silica glass optical fiber. Hereinafter, an example in which the present invention is applied to a silica glass optical fiber including each embodiment will be described.

In the present invention, as described above, since the optical fiber whose light is intentionally emitted from its surface is used, a coating layer (primary coating layer) is provided on the cladding surface. None are used.

FIG. 2 is a schematic diagram showing the structure of an optical fiber constituting a two-dimensional plane in the backlight device of the first embodiment. As shown in FIG. 2, when the ratio of the diameter (core diameter) a of the core 5 to the fiber diameter (clad diameter: clad diameter) b of the structure of the optical fiber 3 is large, the surface of the optical fiber 3 The light 4 is emitted from the. Also, when the difference between the refractive index n1 and the refractive index n2 of the core 5 and the clad 6 is small, the light 4 is similarly emitted from the surface of the optical fiber 3.

The light 4 incident on the optical fiber 3 propagates through the optical fiber while gradually radiating a part of the light from the surface of the optical fiber 3. The intensity distribution of the light 4 coming out of the surface of the optical fiber 3 depends on the traveling direction (X
Direction), the proportion of the light 4 emitted from the surface is small in a portion near the light source 1 so as to be uniform with respect to the light source 1.
The greater the distance, the greater the proportion.

For example, as shown in FIG.
By changing the ratio of the core diameter “a” to the fiber diameter “b” by changing the thickness of the fiber, the amount of emitted light is made constant. Here, only the thickness of the clad is changed, but the core diameter may be changed, or both may be changed. Alternatively, the difference in the refractive index between the core and the clad may be changed appropriately.

That is, in the optical fiber 3, the diameter (core diameter) a of the core 5 is kept constant (a), and the diameter b of the clad 6 (clad diameter) is farthest from the light source at the end b1 on the light source side. Linearly reduced to the other end diameter bn,
Light 7 emitted from the optical fiber 3 at each position on the X coordinate
Is always constant. In FIG. 1B, the emission of light (emitted light 7) is shown constant (uniform) at each position.

The optical fiber bundles do not need to be densely arranged. By providing a certain interval, a slit-shaped backlight device spread on a two-dimensional plane can be obtained.
If wiring is performed in the gap between the optical fibers, light from the backlight device will not be blocked by the wiring portion.

Also, since the optical fiber itself can be bent, the degree of freedom in the spatial shape between the light source and the surface that actually emits light (light emitting surface) as a backlight device, and the light emitting surface itself can also be changed. It will have a spatial degree of freedom. As a result, considering the application to a notebook computer, the light emitting surface itself may be a flat surface and therefore does not necessarily require a degree of freedom, but the fact that there is a degree of freedom between the light source and the surface that actually emits light means that The light source attached adjacent to the side surface of the LCD can be arranged at an arbitrary position such as the back of a keyboard where space is available. It is only necessary to reduce the ratio of the diameter of the core to the light emitting surface to prevent light emission.

In the first embodiment, the number of optical fiber bundles is one.
Although the optical fiber is optically connected to the light sources, it is also possible to connect a different light source for each optical fiber.

According to the first embodiment, the following effects can be obtained.

(1) The optical fiber 3 is a thin and long light guide material, and is characterized by being formally flexible. Therefore, by using the optical fiber 3 as a means for guiding the light 4 from the light source 1 on a two-dimensional plane and a means for uniformly emitting the light 4 on the two-dimensional plane, the light source 1 and the light 4 are actually It is possible to provide a backlight device having a degree of freedom between the emitting surfaces and a degree of freedom of the surface that actually emits the light 4 itself.

(2) Since the optical fiber itself is thinner and longer than a light guide plate made of an acrylic plate or the like used in a conventional backlight device, according to the present invention, a thinner, lighter, and larger screen can be realized. Become.

(3) When a display device is formed by using the backlight device, a display device for performing intensity modulation includes:
By not laying the optical fiber 3 on the parallel wiring portions that do not contribute to the display and not emitting the light 4 from the orthogonal wiring portions, the ratio of the display light emitting area per light emitting area as the backlight device increases, The object of the present invention is to achieve high efficiency.

(4) In the present invention, the periphery of the long light source 1 is covered with the reflector 2, and the coupling portion 8 of the optical fiber 3 is provided in the cover of the reflector 2. Looking at an ideal cross section of this structure, the reflector 2 is arranged such that an elliptical surface having the coupling portion 8 of the light source 1 and the optical fiber 3 as two poles becomes the reflector 2. Therefore, a distribution loss of the optical power unlike the optical distribution path does not occur.

(5) In the present invention, the optical fiber 3 is used from the light source 1 to the radiation part. Due to the structure of the core / clad of the optical fiber 3, the loss of the light is almost the same as the transmission loss used for communication.

(6) According to the present invention, it is possible to provide a high-efficiency, low-power-consumption backlight device which is closer to 100% of the supplied light power than the conventional surface emitting device technology.

(Embodiment 2) FIG. 3 is a schematic diagram showing a structure of an optical fiber bundle in a backlight device according to another embodiment (Embodiment 2) of the present invention.

The second embodiment is an example of a configuration having a back reflector and an end reflector in order to further increase the light use efficiency. In FIG. 3, the optical fiber 3 of the first embodiment is used.
That is, a part of the optical fiber bundle is shown.

The optical fiber 3 used in the present invention has a function of emitting light 4 from the surface thereof. However, the optical fiber 3 emits light 4 on a surface other than the upper surface (upper two-dimensional plane) serving as an actual light emitting surface as a backlight device. Radiation leads to losses. In view of this, in the second embodiment, a back reflector 10 having a structure that is repeatedly bent in a V-shape is provided on the lower surface (back surface) of the optical fiber bundle as a part is separately described below the figure. ,
The structure is such that an end face reflection plate 11 is provided on the other end side of each optical fiber 3.

In the second embodiment, in addition to the backlight configuration using light emitted directly from the optical fiber 3, the light returning from the end face reflection plate 11 and the reflection light collected by the back reflection plate 10 are also used. Since the light source 1 is used as a backlight, the efficiency of use of light incident from the light source 1 can be increased. As a result, effects such as improvement of the light intensity of the backlight device or reduction of the light source output can be obtained.

(Embodiment 3) FIG. 4 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 3) of the present invention, and FIG. It is a schematic diagram which shows the structure of an optical fiber.

In the third embodiment, means for emitting light 4 from the surface of the optical fiber 3 of the first embodiment will be described.

As in the first embodiment, the light incident on the core diameter, the clad thickness, or the difference in the refractive index between the core and the clad, or both, in the fiber structure, is incident on the light traveling direction. There is a means of optimizing for uniform scattering.

In addition, as shown in FIG. 4, the excitation of the skew ray 15 (light ray not passing through the center of the fiber) is shown. There is a method utilizing the light leaked by this. The skew lay 15 transmits the light 4 emitted from the light source 1 to the reflection plate 2
When the light 4 is incident on one end of the optical fiber 3 by using the optical fiber 3, the light 4 can be generated by being incident not only on the core 5 but also on the clad 6 outside the core 5.

In the use of this skew ray 15, 2
In order to make the intensity distribution of the light 4 in the dimensional plane uniform, a structure in which the fiber diameter (core diameter, clad diameter) is appropriately deformed may be employed. FIG. 5 shows an example in which the core diameter is increased and the cladding thickness is increased at the left end (light source side) of the optical fiber 3, and the core diameter is decreased and the cladding thickness is reduced at the right end of the optical fiber 3. With this structure, the light emission distribution can be made uniform.

(Embodiment 4) FIG. 6 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 4) of the present invention, and FIG. It is a schematic diagram which shows the structure of an optical fiber.

In the fourth embodiment as well, means for emitting light 4 from the surface of the optical fiber 3 of the first embodiment will be described. FIG. 6 shows the unevenness 22 on the surface 20 of the optical fiber 3 or the boundary surface 21 between the core 5 and the clad 6 or both.
Is formed to have the scattering structure 23 of the light 4.

For example, when the optical fiber 3 is formed while being drawn while the optical fiber 3 is being drawn, the unevenness 22 can be formed on the boundary surface 21 or the surface 20 by slightly changing the drawing speed. For example, in the process of manufacturing an optical fiber preform using the MCVD method, when depositing the cladding material, unevenness in the movement of the burner for heating causes unevenness on the cladding inner surface of the preform. After the core material is formed, the core material is deposited and collapsed as before, and the resulting material is applied to a drawing device, whereby an optical fiber having an uneven surface at the interface between the core and the clad can be formed. The surface 20 can be easily formed by various mechanical processing methods.

FIG. 7 shows a structure in which the degree of the irregularities 22 is changed in proportion to the distance from the light source. The degree of the irregularities 22 is small at the left end (light source side) of the optical fiber 3, and the degree of the irregularities increases as the distance from the light source increases. This is an example of increasing the size of 22.
With this structure, the light emission distribution can be made uniform.

(Embodiment 5) FIG. 8 is a schematic view showing the structure of an optical fiber in a backlight device according to another embodiment (Embodiment 5) of the present invention, and FIG. It is a schematic diagram which shows the structure of an optical fiber.

In the fifth embodiment as well, means for emitting light 4 from the surface of the optical fiber 3 of the first embodiment will be described. As shown in FIG. 8, the optical fiber 3 of the fifth embodiment has a structure in which scattering materials 25 and scattering structures due to voids are scattered in the core 5 of the optical fiber 3. When the optical fiber 3 is manufactured, the scattering structure may be generated by mixing the scattering material 25 into a portion forming the core, or generating air bubbles by changing the temperature control to generate air bubbles. it can. The optical fiber 3 is formed by pulling out the base material after the scattering substance is mixed or bubbles are generated.

By appropriately changing the amount of the scattering structure according to the distance from the light source, the light emission intensity at each position can be changed. FIG. 9 shows that the amount of the scattering
At the left end (light source side) is an example in which the amount is sparsely reduced and the amount of the scattering material 25 is gradually increased as the distance from the light source increases. This structure makes it possible to make the light emission distribution uniform. .

(Embodiment 6) FIG. 10 is a schematic diagram showing the structure of an optical fiber in a backlight device according to another embodiment (Embodiment 6) of the present invention, and FIG. It is a schematic diagram which shows the structure of an optical fiber.

In the sixth embodiment as well, means for emitting light 4 from the surface of the optical fiber 3 of the first embodiment will be described. The optical fiber 3 of the sixth embodiment has a structure in which a fluorescent substance 30 is dispersed in the core 5 of the optical fiber 3 as shown in FIG. The fluorescent material 30 can be manufactured by mixing the fluorescent material 30 into a portion forming a core when the optical fiber 3 is manufactured. After the fluorescent substance 30 is mixed, the preform is pulled out to form the optical fiber 3. That is, in the sixth embodiment, when light of a certain wavelength (from ultraviolet rays to infrared rays) enters the optical fiber 3, the visible light (wavelength
400nm to 700nm light)
This is an example using the light emission phenomenon (photoluminescence).
As the fluorescent substance, there is a rare earth ion. By scattering the rare earth ion, visible light can be obtained as up-conversion light emission.

By appropriately changing the amount of the fluorescent substance 30 depending on the distance from the light source, the light emission intensity at each position can be changed. FIG. 11 shows an example in which the amount of the fluorescent substance 30 is made sparse at the left end (light source side) of the optical fiber 3 to reduce the amount, and the amount of the fluorescent substance 30 is gradually increased as the distance from the light source increases. Thereby, the light emission distribution can be made uniform.

(Embodiment 7) FIG. 12 is a schematic diagram showing the structure of an optical fiber in a backlight device according to another embodiment (Embodiment 2) of the present invention. In the seventh embodiment, as shown in FIG. 12, light 4 is emitted only to the upper surface (upper two-dimensional plane) of the optical fiber 3 by, for example, shaving only the upper surface serving as an actual light emitting surface as a backlight device. This is an example of having functions. In this structure, the light 4 emitted from the peripheral surface of the optical fiber 3 is only emitted from the flat light emitting surface 35, and efficient emission can be achieved.

In this example, the light emitting surface 35 is inclined, and at the left end (light source side) of the optical fiber 3, the cladding thickness under the light emitting surface 35 is large, and the cladding thickness gradually decreases as the distance from the light source increases. It has a structure. With this structure, the light emission distribution can be made uniform.

In the seventh embodiment, the use efficiency of light can be further enhanced by using the end face reflection plate of the second embodiment at the other end of the optical fiber 3. That is, in this case, the light use efficiency approaches 100%.

(Eighth Embodiment) FIG. 13 is a schematic view schematically showing a backlight device according to another embodiment (Eighth Embodiment) of the present invention. Embodiment 8 is an example in the case where a plurality of light sources are used.

As shown in FIG. 13, in the eighth embodiment, 3
And one optical fiber 3 is connected to the three light sources 1.
With one of the Therefore, three times the brightness can be obtained as compared with the case where all the optical fibers 3 are coupled to one of the same light sources.

That is, in FIG. 13, the inside of the coupling portion is covered with a reflection film, and there is no light emission port other than the end face of the optical fiber. Light from each light source is repeatedly reflected inside each coupling portion. The end face of the optical fiber connected to the joint is
%Reportedly. Therefore, the light source 1 having the same power
In the case where all the optical fibers are combined, three times the power can be used by equally dividing and connecting the optical fibers to three light sources having the same power, so that three times the luminance can be obtained. Obtainable. The maximum brightness can be obtained by preparing light sources by the number of optical fibers and coupling them.

(Embodiment 9) FIG. 14 is a schematic view schematically showing a backlight device according to another embodiment (Embodiment 9) of the present invention. In the ninth embodiment, colorization of the backlight itself will be described.

In FIG. 14, every third optical fiber 3 is divided into three systems. The light source connected to each system is R
(Red), G (green), and B (blue), the optical fiber 3 connected to the light sources 1R, 1G, and 1B of R, G, and B, respectively.
Are arranged in order to form a color backlight device for a color display device. According to this configuration, it is not necessary to attach a color filter to the intensity modulation unit as a color display device,
The efficiency as a display device can be improved.

FIG. 15 is a schematic view showing a coupling portion between an optical fiber and a light source in a backlight device according to a modification of the ninth embodiment, which is another color configuration. In the present embodiment, a white light source 40 is used as a light source, but R, G, and B color filters 41 are provided on an end face (one end face) where light enters each optical fiber 3. According to this configuration, light sources of three colors of R, G, and B are not required as light sources, and the number of components in the backlight device can be reduced and the device can be downsized.

(Embodiment 10) FIG. 16 is a schematic view schematically showing a backlight device according to another embodiment (Embodiment 10) of the present invention. The tenth embodiment has a structure in which the optical fiber 3 is connected to any one of the light sources of the three systems every three lines as in the ninth embodiment. Three
The light source of the system is R as in the case of the ninth embodiment.
(R), G (green) and B (blue) light sources 1R, 1
G, 1B.

A white light source 40 is disposed near each of the light sources 1R, 1G, 1B.
Switching between 0 and the light sources 1R, 1G, 1B is possible. The figure is a schematic diagram, and the switching structure is omitted in particular. For example, the light source located at one focal point of the elliptical reflection plate 2 is switched from the white light source 40 to one of the light sources 1R, The white light source 40 is switched from 1G, 1B or any one of the light sources 1R, 1G, 1B. Further, by changing the cross-sectional shape of the reflection plate 2,
When the white light source 40 is turned on, white light is incident on one end of the optical fiber 3, and the white light source 40 is turned off to turn on the light sources 1R and 1R.
When G and 1B are turned on, light of any one of the three primary colors may be incident on one end of the optical fiber 3.

In the tenth embodiment, the R, G, and B light sources 1
By turning on R, 1G, and 1B, it becomes a color backlight device, and by switching and turning on the white light source 40, it becomes possible to use it as a backlight device for a monochrome display device having three times the luminance.

(Embodiment 11) FIG. 17 is a schematic diagram showing a part of a backlight device and a part of a display device in a display device according to another embodiment (Embodiment 11) of the present invention.
FIG. 18 is a schematic sectional view showing a part of the backlight device and a part of the display device in the display device according to the eleventh embodiment. In the eleventh embodiment, a display device 52 is obtained by combining the backlight device of the ninth embodiment shown in FIG. 14 with an intensity modulator 51 using a liquid crystal (display device) 50.

The intensity modulation section 51 of the liquid crystal 50 has a configuration in which vertical (or horizontal) pixels 53 are arranged in parallel along the optical fibers 3 arranged just at equal intervals.
The display portions of R, G, and B at one end of the optical fiber 3 are as follows:
These are the connections to the red, green, and blue light sources. Each optical fiber 3
There is a gap between them, and the wiring 54 comes in parallel with the optical fiber 3 in the gap. Optical fiber 3
With respect to the wiring 54 which intersects perpendicularly with the optical fiber 3, the light 4 is not radiated at a portion where the wiring 54 and the optical fiber 3 intersect. By doing so, the light emission area of the backlight device is equal to the display light emission area of the display device.

As a result, a structure without a color filter can be provided, and a color display device with high luminance and high efficiency can be provided.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say. For example, in each of the above-described embodiments, an example has been described in which the light emission distribution of the backlight is made uniform (uniform). The present invention can be applied to at least a surface emitting device.

[0093]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

(1) According to the present invention, by using an optical fiber as a means for guiding light on a two-dimensional plane and a means for uniformly radiating light on the two-dimensional plane, light is blocked by wiring. Thus, a highly efficient, thin and lightweight backlight device can be provided.

(2) According to the present invention, the backlight device can be colored by using a plurality of light sources connected to the optical fiber, and by providing switching to a white light source, color and monochrome can be provided. Can be provided. Therefore, a color filter is not required for the non-light-emitting display element, and a display device with high luminance and high efficiency can be provided by combining with the backlight device.

(3) According to the present invention, a backlight device having a degree of freedom between the light source and the surface that actually emits light and the degree of freedom of the surface that actually emits light can be obtained. When used as a backlight of a non-light emitting display device with a high degree of freedom, a display device of an arbitrary shape can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an outline of a backlight device according to an embodiment (Embodiment 1) of the present invention.

FIG. 2 is a schematic diagram showing a structure of an optical fiber constituting a two-dimensional plane in the backlight device according to the first embodiment.

FIG. 3 is a schematic diagram showing a structure of an optical fiber bundle in a backlight device according to another embodiment (Embodiment 2) of the present invention.

FIG. 4 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 3) of the present invention.

FIG. 5 is a schematic diagram illustrating a structure of an optical fiber in a backlight device according to a third embodiment.

FIG. 6 is a schematic diagram showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 4) of the present invention.

FIG. 7 is a schematic diagram illustrating a structure of an optical fiber in a backlight device according to a fourth embodiment.

FIG. 8 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 5) of the present invention.

FIG. 9 is a schematic view illustrating a structure of an optical fiber in a backlight device according to a fifth embodiment.

FIG. 10 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 6) of the present invention.

FIG. 11 is a schematic view illustrating a structure of an optical fiber in a backlight device according to a sixth embodiment.

FIG. 12 is a schematic view showing a structure of an optical fiber in a backlight device according to another embodiment (Embodiment 7) of the present invention.

FIG. 13 is a schematic diagram schematically showing a backlight device according to another embodiment (Embodiment 8) of the present invention.

FIG. 14 is a schematic diagram schematically showing a backlight device according to another embodiment (ninth embodiment) of the present invention.

FIG. 15 is a schematic diagram showing a coupling portion between an optical fiber and a light source in a backlight device which is a modification of the ninth embodiment.

FIG. 16 is a schematic diagram schematically showing a backlight device according to another embodiment (Embodiment 10) of the present invention.

FIG. 17 is a schematic diagram showing a part of a backlight device and a part of a display device in a display device according to another embodiment (Embodiment 11) of the present invention.

FIG. 18 is a schematic sectional view showing a part of a backlight device and a part of a display device in a display device according to Embodiment 11;

FIG. 19 is a schematic view showing an outline of a conventional backlight device.

[Explanation of symbols]

1, 1R, 1G, 1B: Light source, 2: Reflector, 3: Optical fiber, 4: Light, 5: Core, 6: Cladding, 7: Emitted light, 8: Coupling part, 10: Back reflector, 11 ... end face reflection plate, 15 ... skew ray, 20 ... surface, 21 ... boundary surface,
22: unevenness, 23: scattering structure, 25: scattering material, 30 ...
Fluorescent substance, 35 light emitting surface, 40 white light source, 41 color filter, 50 liquid crystal (display device), 51 intensity modulator, 52 display device, 53 pixel, 54 wiring, 7
0: Small fluorescent lamp, 71: Light guide plate, 72: Reflector plate, 7
3: Reflective sheet, 74: Light, 75: Diffusion dot.

Claims (14)

[Claims] 1. A light source and a light emitted from the light source
A backlight device for generating a backlight by means for guiding on a two-dimensional plane and means for emitting the light guided on the two-dimensional plane in a normal direction of the two-dimensional plane, A plurality of optical fibers each comprising a core and a clad arranged in parallel above, and coupling means for coupling light emitted from the light source to one end of each of the optical fibers, the cladding of each of the optical fibers A backlight device, wherein the backlight is generated by light leaking from an outer surface of the backlight. 2. A light source and a light emitted from the light source.
A backlight device for generating a backlight by means for guiding on a two-dimensional plane and means for emitting the light guided on the two-dimensional plane in a normal direction of the two-dimensional plane, A plurality of optical fibers each comprising a core and a clad arranged in parallel above, coupling means for coupling light emitted from the light source to one end of each of the optical fibers, and an upper side of the two-dimensional plane of the optical fibers A mirror provided corresponding to part or all of the peripheral surface and the other end surface excluding the surface that emits light toward the optical fiber, and the light leaks from the outer surface of the cladding of each of the optical fibers, and A backlight device for generating light. 3. The magnitude of the intensity of light radiated from the cladding surface of the optical fiber depends on the difference between the diameter of the core constituting the optical fiber, the thickness of the cladding covering the core, and the refractive index of the core and the cladding. 3. The backlight device according to claim 1, wherein the backlight device is determined by a structure obtained by changing one or more of the configurations. 4. 4. The backlight device according to claim 1, wherein the means for radiating light from the optical fiber is driven by skew ray excitation. 5. The optical fiber according to claim 1, wherein the optical fiber has irregularities on a boundary surface between a core and a clad, an outer surface of the clad, or both. Backlight device. 6. The backlight device according to claim 1, wherein scattering structures caused by scattering materials and voids are scattered in the core of the optical fiber. 7. The backlight device according to claim 1, wherein a fluorescent substance is dispersed in a core of the optical fiber. 8. The back according to claim 1, wherein at least a part of the upper surface of the optical fiber on the two-dimensional plane is cut off to form a light emitting surface. Light device. 9. One or more of the core diameter, clad thickness, refractive index difference, unevenness, scattering material, scattering of fluorescent material, and light emitting surface position are selected and selected by selecting the constituent conditions. The backlight device according to any one of claims 3 to 8, wherein a backlight having the following distribution is generated. 10. One or more of the core diameter, clad thickness, refractive index difference, unevenness, scattering material, scattering of fluorescent material, and light emitting surface position are selected and uniform by selecting the constituent conditions. The backlight device according to any one of claims 3 to 8, wherein the backlight device generates a backlight having a strong light intensity distribution. 11. The apparatus according to claim 1, further comprising a plurality of light sources, and means for coupling each optical fiber to one or more of the plurality of light sources.
The backlight device according to Item. 12. The backlight device according to claim 11, comprising light sources of three primary colors, wherein light emitted from each optical fiber is periodically colored. 13. The backlight device according to claim 11, wherein a light source can be switched when coupling the plurality of light sources and each optical fiber. 14. The method according to claim 1, wherein
13. A display device comprising: the backlight device according to the item [1];