JP2003187607A - Plane light source using optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at improvement of brightness, uniformization and thinning of a light-emitting surface for a plane light source device which illuminates a liquid crystal display device or the like by emitting light from a planar surface such as a plane or a curved face. <P>SOLUTION: The device is provided with an integrated optical fiber sheet with a plurality of optical fibers laterally arranged almost in parallel consisting of a first optical fiber part with a first end face, a second optical fiber part with a second end face, and a third optical fiber part having a curved part and situated between the first optical fiber part and the second optical fiber part. The first optical fiber part is provided with a plurality of either leaking means or light-emitting means for leaking or emitting light, the second optical fiber part is provided with a light-transmitting means, and the third optical fiber part is provided with a light-coupling means of the first optical fiber part and the second optical fiber part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device, that is, a surface illumination device. More specifically, a backlight for illuminating a passive display device such as a liquid crystal display device, a viewer for illuminating a light-transmitting image film such as a photographic film, an illuminated keyboard having a keypad for emitting light, an illuminated membrane (switch), The present invention relates to a surface light source device having a flat or curved light emitting surface used for surface illumination in various fields such as an exhibition panel such as an illuminated signboard.

[0002]

2. Description of the Related Art A conventional typical first type surface light source device uses a light guide plate made of acrylic resin, polycarbonate resin, or the like having a substantially rectangular surface and a substantially quadrangular surface (that is, a rectangular shape). Substantially linear light sources such as a straight tube fluorescent lamp and a plurality of linearly distributed light emitting diodes are arranged on the side surfaces of the four or four side surfaces. Then, light is emitted from one surface of the light guide plate to illuminate, for example, a liquid crystal display device, a light transmission image film or the like that does not emit light by itself.

The second type of conventional surface light source device (planar lighting device) uses a plurality of optical fibers and at least an illumination surface (light emission surface) is an optical fiber sheet (optical fiber tape, optical fiber ribbon). ) Is used for the optical fiber cable. A second type of conventional surface light source device is disclosed in, for example, JP-A-64-57206 (US Pat. No. 4,845,596, JP-A-1-197).
902 (Patent No. 2629769), JP-A-5-210017 (Patent No. 3193125, US Pat. No. 5,036,435), JP-A-4-7506 (US Pat. No. 5,036). , 435
No.), JP-A-4-143705, JP-A-20
No. 00-47038 is known.

The inventions described in the above documents and
Basically, a plurality of optical fibers are arranged in parallel to form a sheet shape (tape shape, ribbon shape) and an optical fiber sheet (or an optical fiber sheet portion) is formed with a light leakage portion as an illumination surface. is there. Then, light rays are leaked from the illumination surface and emitted to form a planar illumination surface (light emission surface).
Then, one end of the optical fiber sheet is used as a light incident part and a linear light source is arranged to face the light incident part, or one end of an optical fiber cable having an optical fiber sheet part is extended and converged to make a light beam. The optical fiber
A light ray emitted from a point light source arranged apart from the sheet portion is made incident from a light ray incident portion which is a converging portion of the optical fiber cable.

Further, as a surface light source device (planar lighting device) using a plurality of optical fibers, US Pat. No. 5,042,
892, U.S. Pat. No. 5,461,548, wherein a plurality of optical fibers each of which is curved in a substantially U shape are arranged laterally on a substantially plane, and Light is made to enter from two end face parts (incident part),
Surface light source device (fiber optic light panel, fiber optic backlight illumination) that emits light from both of two U-shaped legs (linear portions) of each optical fiber arranged on a substantially plane Apparatus) is disclosed.

[0006]

In the market of liquid crystal display devices used for personal computer monitors and television receivers, the size of the screen has been increased to approximately 19 inches or more while keeping the display brightness uniform, and has been made thinner and lighter. Has become more and more demanded in recent years.

Further, in portable information terminal equipment having a built-in liquid crystal display device such as a mobile phone, a portable personal computer, a notebook personal computer and a portable electronic notebook, in recent years, the liquid crystal display device has become thinner and lighter while maintaining the uniformity of the display brightness. It is required to increase the size and size of limited equipment in the case.

The above-mentioned conventional surface light source device used as a backlight of a liquid crystal display device is not satisfactory in terms of the uniformity of surface luminance, the increase in screen size, the reduction in thickness, and the reduction in weight required by the market in recent years. Absent.

The conventional surface light source device using the above-described light guide plate has a large light transmission loss and a low light transmission efficiency, and requires a light source of higher brightness and a larger number of light sources as the area increases.
In addition, it is necessary to increase the thickness of the light guide plate, power consumption,
The total weight and the space for accommodating a large number of light sources increase, and there is a drawback that power saving, thinning, and weight reduction become difficult as the area increases.

A conventional surface light source using the above-mentioned light guide plate is a straight tube type fluorescent tube which emits a uniform light beam in its length direction,
Since a linear light source such as a straight tube cold cathode fluorescent tube is arranged on the linear side surface (incident part) of the light guide plate, the central part near the incident part of the light guide plate and the substantially central part of the exit surface are It is brighter than other parts, display unevenness occurs, the uniformity of the surface brightness cannot be obtained, and there are major drawbacks that the surface brightness cannot be made constant in all parts of the emission surface. A number of inventions for improving this have been disclosed in patent publications and the like, but there is a drawback that the structure is complicated and the cost is increased, and it is difficult to reduce the thickness and the weight.

The inventions described in the above-mentioned documents and the above have the advantage of arranging the light source only on one end side of the surface light source device, but the optical fiber having this kind of light leakage portion is limited in the light transmission distance. Especially, when the surface light source is used for a backlight of a liquid crystal display device having a large screen of, for example, about 19 inches or more, a light beam incident from one end of an optical fiber sheet having a large number of light leakage portions is incident on the other end. Rays are not transmitted to the part or are transmitted only slightly.

Therefore, according to the inventions described in the above-mentioned documents or the above, the effective surface of the optical fiber sheet has a high surface brightness in the vicinity of the light source (bright), but the surface brightness decreases (becomes darker) as the distance from the light source increases, and light leakage occurs. Even if various measures are taken for the parts, there is an unavoidable defect that unevenness in surface brightness (irregularity of illuminance) occurs as a whole.

US Pat. No. 5,042,89 of the above document
No. 2, in the invention of U.S. Pat. No. 5,461,548 of the above-mentioned document, light is emitted from both of two legs of optical fibers arranged in a U shape in a horizontal direction on a plane. Therefore, the surface brightness near the light source on the effective emission surface is high (bright), but the surface brightness decreases (becomes darker) as the distance from the light source increases, and uneven surface brightness (irregularity in illuminance) occurs as a whole. Especially, when the surface light source is used for a backlight of a large-area liquid crystal display device, there is a drawback that unevenness of surface brightness increases.

The present invention provides a surface light source device which eliminates the above-mentioned drawbacks of the conventional surface light source device.

[0015]

According to a surface light source device of a first aspect of the present invention, a plurality of optical fibers are arranged substantially parallel to each other in a lateral direction, and a first optical fiber portion having a first end face and a first optical fiber portion are provided. And a second optical fiber portion having two end faces, and a third optical fiber portion having a curved portion which is located between the first optical fiber portion and the second optical fiber portion and is substantially a sheet. A unitary optical fiber sheet, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion is It is characterized in that it has means for transmitting a light beam, and the third optical fiber portion has means for optically coupling the first optical fiber portion and the second optical fiber portion.

A surface light source device according to a second aspect of the present invention has a plurality of optical fibers arranged substantially parallel to each other in a lateral direction and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and the first optical fiber section and the second optical fiber section. And are arranged vertically adjacent to each other.

According to a third aspect of the present invention, the surface light source device has a plurality of optical fibers arranged substantially parallel to each other in the lateral direction and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. It is characterized by comprising a plurality of groove portions formed in the fiber portion.

A surface light source device according to a fourth aspect of the present invention has a plurality of optical fibers arranged substantially parallel to each other in a lateral direction and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. Form a gradation pattern in the fiber part,
It is characterized in that light rays are emitted from substantially the entire surface of the first optical fiber portion with substantially uniform brightness.

According to a fifth aspect of the present invention, in a surface light source device, a plurality of optical fibers are arranged substantially parallel to each other in a lateral direction and have a first optical fiber portion having a first end surface and a second end surface. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. Form a gradation pattern in the fiber part,
The gradation pattern is one in which the distribution density of the leaking means (or the emitting means) is reduced from approximately the middle of the first optical fiber portion toward both ends thereof.
Is characterized in that light rays are emitted from substantially the entire surface of the optical fiber portion with substantially uniform brightness.

A surface light source device according to a sixth aspect of the present invention has a plurality of optical fibers arranged substantially parallel to each other in a lateral direction and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. The first optical fiber comprises a plurality of grooves formed in the fiber portion. A gradation pattern is formed in the bar portion, and the gradation pattern is one in which the distribution density of the groove portion is reduced from approximately the middle of the first optical fiber portion toward both ends thereof. Is characterized in that a light beam is emitted from substantially the entire surface of the above with substantially uniform brightness.

A surface light source device according to a seventh aspect of the present invention has a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. The first optical fiber comprises a plurality of grooves formed in the fiber portion. A gradation pattern is formed in the bar portion, and the gradation pattern is formed by reducing the height (that is, the depth) of the groove portion from approximately the middle of the first optical fiber portion toward both ends thereof. It is characterized in that a light beam is emitted from substantially the entire surface of the first optical fiber portion with substantially uniform brightness.

A surface light source device according to claim 8 of the present invention has a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and a plurality of leaking means (or emitting means) are provided for the first optical fiber. The first optical fiber comprises a plurality of grooves formed in the fiber portion. A gradation pattern is formed in the bar portion, and the gradation pattern is formed by reducing the width of the groove portion from substantially the middle of the first optical fiber portion toward both ends thereof. It is characterized in that light rays are emitted from substantially the entire surface with substantially uniform brightness.

The surface light source device according to claim 9 of the present invention has a plurality of optical fibers arranged substantially parallel to each other in the lateral direction and has a first optical fiber portion having a first end face and a second end face. A second optical fiber portion and a third optical fiber portion which is located between the first optical fiber portion and the second optical fiber portion and has a curved portion and which is substantially sheet-like integrated. An optical fiber sheet is provided, the first optical fiber portion has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, and the second optical fiber portion has a light beam transmitting means. However, the third optical fiber section has an optical coupling means for connecting the first optical fiber section and the second optical fiber section, and the second optical fiber section and the third optical fiber section. Each of the optical fibers of the The optical fiber of the first optical fiber portion has a clad having a refractive index lower than that of the core, and the optical fiber of the first optical fiber portion has a clad having a refractive index lower than that of the core and selectively covering the surface of the core. The exposed portion of the core which is not formed is the leaking means (or the emitting means).

A surface light source device according to a tenth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, in which the first optical fiber portion and the second optical fiber portion are provided. It is characterized in that a laminated body is formed with an adhesive member interposed therebetween.

The surface light source device according to claim 11 of the present invention is the surface light source device according to any one of claims 1 to 9 in which the first optical fiber portion and the second optical fiber portion are provided. A laminated body having an adhesive member interposed therebetween is formed, and the adhesive member is made of a substantially transparent organic resin adhesive in which a plurality of light scattering particles are dispersed.

A surface light source device according to a twelfth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, in which the first optical fiber portion and the second optical fiber portion are provided. It is characterized in that a mirror member is interposed therebetween.

A surface light source device according to a thirteenth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, wherein the first optical fiber portion is provided with a transparent member for covering the leaking means. Further, the transparent member has a refractive index equal to or higher than that of the core of the optical fiber.

A surface light source device according to a fourteenth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, wherein the first optical fiber portion is provided with a transparent member for covering the leaking means. Further, the transparent member is made of a substantially transparent organic resin having a refractive index equal to or higher than that of the core of the optical fiber.

A surface light source device according to a fifteenth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, wherein the first optical fiber portion is provided with a transparent member for covering the leaking means. The transparent member is made of a substantially transparent organic resin having a refractive index equal to or higher than that of the core of the optical fiber, and a plurality of light scattering particles are dispersed in the organic resin.

A surface light source device according to a sixteenth aspect of the present invention is the surface light source device according to any one of the first to ninth aspects, wherein the first optical fiber portion is provided with a transparent member for covering the leaking means. The transparent member is made of a substantially transparent organic resin having a refractive index equal to or higher than that of the core of the optical fiber, and a plurality of light scattering particles made of a pigment are dispersed in the organic resin. .

A surface light source device according to claim 17 of the present invention comprises the surface light source device according to any one of claims 1 to 9 and at least one light source, and the first end face and the second The end faces of the two ends substantially at the same position and receive the light beam from the light source.

The surface light source device according to claim 18 of the present invention comprises the surface light source device according to any one of claims 1 to 9 and at least one light source, and the first end surface and the second End faces are vertically arranged adjacent to each other and receive light rays from the light source.

A surface light source device according to claim 19 of the present invention comprises the surface light source device according to any one of claims 1 to 9 and at least one substantially linear light source.
And the second end surface terminate at substantially the same position, are vertically arranged adjacent to each other, and receive a light beam from the light source.

The optical fiber cable used in the present invention is
An optical fiber sheet formed by arranging a plurality of optical fibers in parallel in the lateral direction into a sheet shape (that is, ribbon shape, tape shape) or at least an illuminating section (that is, a light leak section, an illuminating section,
This is an optical fiber cable in which the main part, which should be the light leaking part and the light emitting part), has an optical fiber sheet part.

The plurality of optical fibers are integrated into a sheet shape (that is, ribbon shape, tape shape) by some fixing means. The fixing means holds a parallel arrangement of a plurality of optical fibers and integrates them. As the above-mentioned fixing means, for example, a means for fixing a plurality of adjacent optical fibers with an adhesive (or an adhesive),
Fixing a plurality of optical fibers on the adhesive surface of the adhesive-attached sheet (support) on which the adhesive is applied in advance,
An example is one in which a plurality of optical fibers are fixed by a plastic coating that covers them.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments of a surface light source device of the present invention will be described in detail below with reference to a plurality of drawings.
In the drawings, the same or similar parts are designated by the same reference numerals. This avoids duplication of explanation as much as possible.

A first embodiment of the surface light source device of the present invention will be described with reference to FIGS. 1, 2 and 3.

FIGS. 1, 2 and 3 show a second embodiment of the surface light source device of the present invention. 1 is a conceptual perspective view of the first embodiment, FIG. 2 is an enlarged sectional view taken along the line 30-31 of FIG. 1, and FIG. 3 is an enlarged cutaway taken along the line 40-41 of FIG. FIG.

A surface light source indicated by reference numeral 300 as a whole is composed of a first light guide portion 310, a second light guide portion 320 and a third light guide portion 330.

The first light guide portion 310 functions as an illuminating means (light emitting means) for leaking and emitting light and a light transmitting means. The second light guide portion 320 functions exclusively as an optical transmission means (optical transmission dedicated means). The third light guide portion 330 functions as an optical coupling means and a light transmission means.

The third light guiding portion 330 is optically located in the middle of the first light guiding portion 310 and the second light guiding portion 320. The third light guide portion 330 is the first light guide portion.
310 and the second light guide portion 320 are optically coupled with maximum transmission efficiency with almost no light leakage. Third
The light guide portion 330 of the third light guide portion 330 transmits the light ray L2 transmitted through the second light guide portion 320 and reaching the entrance portion (the lower side of FIGS. 1 and 2) of the third light guide portion 330. Is transmitted along the curved portion of the third light guide portion 33 to change the direction of the light ray L2.
No. 0 exit portion (upper side in FIGS. 1 and 2) is reached and introduced into the second light guide portion 320. The light ray L2 introduced into the second light guide portion 320 is transmitted in the direction of the first light ray incident end E1.

A sheet-shaped optical fiber cable (optical fiber sheet) 300 has a plurality of optical fibers laterally adjacent to each other or arranged in parallel at a predetermined interval.
It is substantially planar and extends in its lengthwise direction.

Further, a sheet-shaped optical fiber cable 300
Is composed of a plurality of first optical fibers 311, a plurality of second optical fibers 321, and a plurality of third optical fibers 331, each having different functions as described below.

The plurality of first optical fibers 311 function as light leakage or light emitting means, and the plurality of second optical fibers 311
21 functions exclusively as an optical transmission means, and the plurality of third optical fibers 331 functions as an optical coupling means for the first optical fiber 311 and the second optical fiber 321.

The first optical fiber 311, the second optical fiber 321, and the third optical fiber 331 have cores 311a, 321a and 321a having high refractive index and high transmission efficiency, respectively.
331a and claddings (ie, claddings) 311b, 321b and lower refractive index than these cores and
331b and.

In this embodiment, a stepped index (SI) type optical fiber having a core / clad structure is used as a raw material. This optical fiber 3
11, 321 and 331 are cores 311a,
321a and 331a and clads 311b, 321b and 331b respectively covering these cores. The core has a high refractive index and the cladding has a high refractive index. Ray of light
The total internal reflection of L1 and L2 is repeated due to the difference in refractive index between the core and the clad, and transmitted in the longitudinal direction thereof.

The optical fibers 311, 321 and 3
31 are cores 311a, 321a and 33, respectively.
1a and clad 311 covering these cores, respectively
b, 321b and 331b, the refractive index of the core is set higher than that of the clad, and the light rays L1 and L2 introduced from the light incident ends E1 and E2 of a plurality of optical fibers are refracted to the core and the clad. The total internal reflection is repeated due to the difference between the two and transmitted in the longitudinal direction thereof.

As shown in FIGS. 1 to 3, the first optical fiber 311 has a plurality of first end faces (light incident end portions) E1, and the second optical fiber 321 has a plurality of second end faces ( Light incident end) E2. The plurality of first end surfaces E1 and the plurality of second end surfaces E2 are arranged vertically adjacent to each other or close to each other.

The first end surface E1 and the plurality of second end surfaces E2 are arranged to face at least one substantially linear light source 200 such as a cold cathode fluorescent lamp. Light rays L1 and L2 from the light source 200 (light rays directly emitted from the light source shown in FIG. 2 and light rays reflected by the reflecting mirror 210) are a plurality of first end faces E.
1 and the plurality of second end faces E2 to the first optical fiber 311
And the second optical fiber 321.

A plurality of first optical fibers 311, a plurality of first optical fibers
2 optical fibers 321 and a plurality of third optical fibers 3
33 are adhesively bonded by adhesives 312 and 322 respectively so as to be fixed laterally adjacent to each other so as to form a substantially flat integrated sheet-like body as shown in FIGS. 1 and 3. Has been converted.

In the present invention, a glass type optical fiber whose core is made of inorganic glass or a plastic type optical fiber whose core and clad are both made of plastic (polymer) can be used.

Since the glass type optical fiber has excellent transmission efficiency, it is suitable for a large area surface light source. Plastic type optical fiber is cheaper than glass type optical fiber, and it is robust against mechanical shock and bending,
It is lightweight. Therefore, considering the harsh usage environment of a notebook personal computer having a liquid crystal display (LCD) as a display unit, a mobile information terminal device, a mobile phone, etc., a plastic type light is used for a surface light source used in the liquid crystal display. It is desirable to use fibers.

A plastic optical fiber of this type is commercially available from Mitsubishi Rayon Co., Ltd. under the trade name "ESKA". This plastic optical fiber (P
The OF) product catalog is available on the Internet at the following home page of Mitsubishi Rayon Co., Ltd. -URL: http://www.mrc.co.jp/dep/pofeskae/comme/comm
e.htm-

"ESCA" plastic optical fibers include optical fiber cores (bare / optical fibers), sheet (ribbon, tape) -shaped optical fiber cables, etc.
For example, the diameter of the optical fiber core wire is about 0.1 mm to about 3.0 mm.

The plurality of first optical fibers 311 corresponding to the first light guide portion 310 of the surface light source 300 have a substantially linear cross section in the longitudinal direction thereof. Then, a plurality of light beam emission parts (light leakage parts, light leakage parts, so that the light beams transmitted inside the first optical fiber 311 are emitted (scattered) from their surfaces to the outside.
A light leak part) is provided.

The plurality of second optical fibers 321 corresponding to the second light guide portion 320 of the surface light source 300 has a substantially linear cross section and a surface similarly to the first optical fiber 311.

However, unlike the first optical fiber 311, the light ray transmitted through the inside of the second optical fiber 321 is transmitted through the inside of the second optical fiber 321 with the maximum transmission efficiency with almost no leakage of the ray. To do.

The plurality of third optical fibers 331 corresponding to the third light guide portion 330 of the surface light source 300 are completely different from the first optical fiber 311 and the second optical fiber 321.
It has a curved, substantially non-linear cross section.

As shown in FIGS. 1 and 2, the third optical fiber 331 has, for example, a curved surface forming an arc or semicircular cross section having a bending radius R.

The permissible value of the bending radius R changes almost in inverse proportion to the diameter of the optical fiber (one optical fiber core wire). That is, the thinner the optical fiber is, the smaller the transmission loss is. Therefore, the bending radius can be reduced, and a sufficient amount of transmitted light can be obtained.

By using an optical fiber having a small diameter as the physically continuous optical fibers 311, 321, 331 constituting the surface light source 300 , the bending radius R of the third optical fiber 331 can be reduced first. Therefore, the protruding portion 331c (see FIG. 2) of the third optical fiber 331 shown in FIG. 2 can be almost ignored, and the entire upper surface and the lower surface of the surface light source 300 can be made substantially flat. Secondly, by using an optical fiber having a small diameter as the surface light source 300, it is possible to provide an optimum surface light source for a backlight for an ultralight and ultrathin liquid crystal display device.

The light ray L2 from the light source 200 received by the second end face of the second optical fiber 321 reflects the total internal reflection (TIR) of the inside of the second optical fiber 321.
section) is repeated to proceed in the direction of the third optical fiber 331, and the third optical fiber 331 can be transmitted with high transmission efficiency with almost no leakage.
Of the optical fiber 331.

Next, this light ray L2 propagates in the direction of the first optical fiber 311 by repeating total internal reflection inside the third optical fiber 331 having a curved nonlinear cross section, and almost leaks while changing its traveling direction gradually. Without reaching, the optical fiber reaches the entrance of the third optical fiber 331 with high transmission efficiency.

That is, the light ray L2 is transmitted through the curved third optical fiber 331, so that the direction thereof is converted to the direction opposite to the direction received by the second end face of the second optical fiber 321.

The redirected light beam L2 is reflected by the first optical fiber 3
11 inside the first optical fiber 311
The light is emitted to the outside while illuminating the LCD display device 480 while advancing in the direction of the end face.

In the first embodiment using the stepped index type optical fiber, the plurality of first optical fibers 311 in the first light guide portion 310 are respectively provided with a plurality of light leaking portions (light emitting portions, light leaking portions). ) As a plurality of grooves 500
Has (Groove).

With this groove portion 500, the clad 311b (and the core 311a) of the first optical fiber 311 is partially deleted or removed in order to emit (scatter) the light beam traveling in the first optical fiber 311 to the outside. To be done.

The groove 500 has a depth indicated by "d" in FIG. 2 in the first optical fiber 311, and partially exposes the core 311a, so that the light beam is emitted from the inside of the optical fiber to the outside.

The second and third optical fibers 321 and 331 in the second and third light guide portions 320 and 330 are different from the first optical fiber 311 in the first light guide portion 310 in the second and third optical fibers 321 and 331. Core 321
Both a and the third core 331a have the second clad 321b and the third clad 331b that completely cover them, and have no groove 500 at all. Therefore, the light rays are transmitted efficiently, that is, with almost no leakage.

The plurality of grooves 500 are formed in the first optical fiber 31.
It can be distributed and arranged in a predetermined pattern as a whole on one main surface.

The predetermined pattern formed by the plurality of grooves 500 increases in density (quantity) of the plurality of grooves 500 from the plurality of first end faces E1 receiving the light ray L1 toward the center of the main surface thereof, and Third optical fiber 3 from its center
First gradually decreasing toward 31
Gradation Patter
It is desirable to arrange and distribute as n).

The plurality of grooves 500 are formed in the first optical fiber 31.
Of the optical fiber cable 300 in a substantially flat sheet shape (that is, a ribbon shape or a tape shape) by arranging the distribution density on the main surface of 1 in a gradation pattern as described above. It is possible to make the surface brightness uniform.

An adhesive member such as an adhesive film 600 in which a large number of light-reflecting particles 600a are dispersed in a transparent adhesive is used to form substantially planar first and second optical fibers 310 and 32.
It can be interposed between 0. By doing so, the first and second optical fibers 310 and 320 are integrated into a substantially linear cross section in their longitudinal direction as a whole.

The adhesive film 600 reflects the light rays traveling downward from the first optical fiber 310 into the light-reflecting particles 600.
The first optical fiber 310 is turned up by a.
It is emitted from the surface of the. Furthermore, the second optical fiber 3
The formation of a mirror layer (not shown) on the front surface of 21 increases the redirecting of light rays traveling in the downward direction in the upward direction.

Therefore, the surface light source device 300 according to the first embodiment can uniformly illuminate all effective display surfaces of a passive display device such as a liquid crystal display device (LCD) 400.

FIG. 4, FIG. 5 and FIG. 6 show a second embodiment of the surface light source device of the present invention.

FIG. 4 is a conceptual perspective view of the second embodiment,
5 is an enlarged cross-sectional view taken along line 50-51 of FIG. 4 and FIG. 6 is an enlarged cross-sectional view taken along line 60-61 of FIG.

4, 5 and 6 showing the second embodiment, the same or similar reference numerals as those used in FIGS. 1, 2 and 3 showing the first embodiment are designated by the same reference numerals. , The same or similar parts are shown. Therefore, the portions having the same or similar reference numerals will be omitted or simply described as much as possible in order to avoid redundant description.

The surface light source 350 has a sheet shape having a first light guiding portion 310 having a linear cross section, a second light guiding portion 320 having a linear cross section, and a third light guiding portion 330 having a substantially non-linear cross section. It consists of ribbon-shaped and tape-shaped optical fiber cables.

The first light guide portion 310 functions as a lighting means and a light transmission means for leaking and emitting light. The second light guide portion 320 functions as a means dedicated to light transmission. Third
The light guide portion 330 functions as an optical coupling means and a light transmission means.

The third light guiding portion 330 is the first light guiding portion 3
It is located in the middle of 10 and the second light guide portion 320. The third light guide portion 330 optically couples the first light guide portion 310 and the second light guide portion 320 with maximum transmission efficiency with almost no light leakage. Third light guide portion 3
Reference numeral 30 denotes a second light guide portion 320 in order to introduce the light beam transmitted through the second light guide portion 320 into the first light guide portion 310.
To change the direction of the transmitted ray.

Further, the plurality of first optical fibers 311 corresponding to the first light guide portion 310 of the surface light source device 350 have a substantially linear cross section and a main surface. The light rays transmitted inside the first optical fiber 311 are the first and / or the second.
Is emitted (scattered) from the main surface of the outside.

The plurality of second optical fibers 321 corresponding to the second light guide portion 320 of the surface light source 350 , like the first optical fiber 311, are substantially linear in cross section and substantially planar. And has first and second major surfaces. The light beam transmitted through the inside of the second optical fiber 321 is transmitted through the inside of the second optical fiber 321 with the maximum transmission efficiency with almost no leakage.

The plurality of third optical fibers 331 corresponding to the third light guide portion 330 of the surface light source 350 are completely different from the first optical fiber 311 and the second optical fiber 321.
It has a curved, substantially non-linear cross section.

Each of the plurality of first optical fibers 311 has a plurality of groove portions 500 (grooves). The groove 500 allows the cladding 31 of the first optical fiber 311 to be formed.
1b (and the core 311a) is partially deleted or removed in order to emit (scatter) the light beam traveling in the first optical fiber 311 to the outside.

The plurality of grooves 500 are formed in the first optical fiber 31.
1 is formed in a predetermined pattern. Multiple grooves 500
Density (quantity) increases from the plurality of first end faces E1 receiving the light ray L1 toward the center of the main surface thereof, and gradually decreases from the center toward the third optical fiber 331. It is desirable to arrange and distribute it as a gradation pattern.

A plurality of grooves 500 are formed in the first optical fiber 31.
1 is composed of a substantially flat sheet-like (that is, ribbon-like or tape-like) optical fiber cable by arranging the distribution density of 1 on the main surface while changing it stepwise as a gradation pattern as described above. Surface light source device 350
It is possible to make the surface brightness of the film uniform.

In FIGS. 4, 5 and 6, the groove portion 5 is formed so that the light transmitting member 360 such as a transparent layer covers almost all of the cores 311a and the claddings 311b.
00 is located in front of the first optical fiber 311.

The light transmitting member 360 is preferably a transparent plastic material (polymer, organic resin) having a refractive index higher than that of the core 311a.

By doing so, the inside of the core of the first optical fiber 311 is transmitted by total internal reflection and the groove 50 is formed.
The light ray incident on the core exposed portion 310 (see FIG. 6) formed by the zero is a light transmitting member 360 having a refractive index equal to or higher than the refractive index of the core 311a instead of the clad 311b having a lower refractive index than the core 311a. I will come into contact with you.

Therefore, the light ray incident on the groove portion 500 leaks from the core exposed portion 310 to the outside through the light ray transmitting member 360 without being totally internally reflected in the core, and is emitted.

Further, it is desirable that the light transmitting member 360 has a large number of light scattering particles 360a dispersed therein for scattering the light rays incident thereon. As the light scattering particles 360a, beads made of transparent glass or polymer, or white pigment particles can be used.

As described above, the optical fiber core 311a
Assuming that the refractive indices of the clad 311b and the transparent member 360 are N1, N2, and N3 in this order, the relationship between them is N.
1 is greater than N2, N3 is greater than N1 (N1> N2, N3>
N1) is preferable, and by doing so, the light rays incident on the groove portion 500 of the first optical fiber 311 are efficiently leaked to the outside from the core exposing portion 310 via the light ray transmitting member 360 and emitted. You can

As an example of a specific material showing the above-mentioned preferable relationship, a polymethylmethacrylate resin (PMMA, refractive index N1: about 1.49) is used as a core, and a polyvinylidene fluoride resin (refractive index N2: about 1.49) is used as a clad. 1.4
A plastic optical fiber using a polymer having a refractive index lower than that of the core 0) or the like can be used as the transmissive member 360 in combination with an ultraviolet curing epoxy resin (refractive index N3: about 1.56).

Other suitable other examples include polystyrene resin (PS, refractive index N1: about 1.59), polycarbonate resin (PC, refractive index N1: about 1.58) or silicone rubber (PC, refractive index) as the core. Rate N1: about 1.47),
Polyvinylidene fluoride resin as the clad (refractive index N
2: about 1.40), a plastic optical fiber using a polymer having a refractive index lower than that of the core
UV curing epoxy resin (refractive index N3: about 1.5
It can be used in combination with 6).

As still another preferable example, polystyrene resin (PS, refractive index N1: about 1.59) and polycarbonate resin (PC, refractive index N1: about 1.58) are used as the core.
Alternatively, a plastic light using a polymer having a lower refractive index than the core such as a silicone resin or rubber (PC, refractive index N1: about 1.47), and a cladding such as polyvinylidene fluoride resin (refractive index N2: about 1.40). The fiber is made of an ultraviolet curing epoxy resin (refractive index N3:
It can be used in combination with about 1.56).

A polymer having a lower refractive index than the core, such as a silicone resin or rubber (PC, refractive index N1: about 1.47) as the core and a polyvinylidene fluoride resin (refractive index N2: about 1.40) as the clad. A plastic optical fiber using a polymethylmethacrylate resin (PMMA, refractive index N1: about 1.49) as a transparent member 360,
Polystyrene resin (PS, refractive index N1: about 1.59),
Polycarbonate resin (PC, refractive index N1: approx. 1.5
It can be used in combination with 8).

Referring to FIG. 7, in a surface light source device 370 according to a third embodiment of the present invention, a plurality of optical fibers are arranged substantially parallel to each other in the lateral direction, and a first light having a first end surface E1 is formed. The second optical fiber portion 321 having the fiber portion 311 and the second end surface E2, and the third light having a curved portion located between the first optical fiber portion 311 and the second optical fiber portion 321. The first optical fiber portion 311 includes a plurality of leaking means (or emitting means) 520 for leaking (or emitting) a light beam. And the second optical fiber portion 321 has a light beam transmitting means, and the third optical fiber portion includes the first optical fiber portion 311 and the second optical fiber portion.
And an optical coupling means with the optical fiber section 321.

The plurality of leaking means (or emitting means) 520 comprises a plurality of groove portions 520 formed in the first optical fiber portion 311. The plurality of groove portions 520 are gradation patterns in the first optical fiber portion 311. And the gradation pattern is formed by reducing the height (that is, the depth) of the groove portion 520 from substantially the middle of the first optical fiber portion 311 toward both ends thereof. Light rays are emitted from substantially the entire surface of the portion 311 with substantially uniform brightness. On the other hand, unlike this, in the surface light source device according to the first and second embodiments of the present invention, the plurality of groove portions 500 are formed in the first optical fiber 311 as described above.
Are arranged by gradually changing the distribution density on the main surface.

As shown in FIG. 7, in the surface light source device 370 according to the third embodiment of the present invention, the plurality of groove portions 520 have a constant distribution density on the main surface of the first optical fiber 311 and a plurality of groove portions 520. Groove 5 in which the depth "d" of the groove 500 is changed stepwise
It is the second gradation pattern with a depth of "d" of 00.

Reference numeral 520 in FIG. 7 indicates a plurality of grooves in this embodiment. Reference numeral 520a is a groove portion having the smallest height (the shallowest depth) formed in the first optical fiber 311 in the vicinity of the plurality of first end faces E1 for receiving the light ray L1 and in the vicinity of the terminal opposite thereto. And reference numeral 520b
Indicates a groove formed at approximately the center of the length of the first optical fiber 311 and having the largest height (the deepest depth). The plurality of grooves 520 of the first optical fiber 311 increase in depth (height) “d” in a stepwise manner from the plurality of first end faces E1 that receive the light ray L1 toward the center of the main surface thereof. And the optical fiber cable (optical fiber sheet) 3 formed on the main surface so as to gradually decrease in the direction from the center to the third optical fiber 331.
It is possible to make the surface brightness of 31 uniform.

The first gradation pattern in the first and second embodiments of the present invention due to the stepwise change of the distribution density of the groove portion 520 and the third embodiment due to the stepwise change of the groove depth. The second gradation pattern has the same function and effect, and both can be said to be the same or equivalent.

Referring to FIG. 8, a surface light source device 380 according to the fourth embodiment of the present invention has a plurality of optical fibers arranged substantially parallel to each other in the lateral direction, and has a first end face E1. A second optical fiber portion 321 having a fiber portion 311 and a second end face, and a third optical fiber having a curved portion located between the first optical fiber portion 311 and the second optical fiber portion 321. The first optical fiber portion 311 includes a plurality of leaking means (or emitting means) 530 for leaking (or emitting) a light beam. And the second optical fiber portion 321 has a light beam transmitting means, and the third optical fiber portion 331 has an optical coupling means for connecting the first optical fiber portion and the second optical fiber portion 321. And have.

The plurality of leaking means (or the emitting means) are composed of a plurality of groove portions 530 formed in the first optical fiber portion, and the plurality of groove portions 530 are formed in the first optical fiber portion 311.
In the gradation pattern, the width of the groove portion is reduced from substantially the middle of the first optical fiber portion 311 toward both ends thereof, and the gradation pattern of the first optical fiber portion 311 is formed. Light rays are emitted from substantially the entire surface with substantially uniform brightness.

As shown in FIG. 8, in a surface light source device 380 according to the fourth embodiment of the present invention, a plurality of grooves 530 are provided in the first optical fiber 3.
The third gradation pattern is formed by the widths of the groove portions 530 in which the distribution density on the main surface of 11 is constant and the widths of the plurality of groove portions 530 are changed stepwise.

Reference numeral 580 in FIG. 8 indicates a plurality of grooves in this embodiment. Reference numeral 580a designates the smallest width formed in the first optical fiber 311 in the vicinity of the plurality of first end faces E1 for receiving the light ray L1 and in the vicinity of the terminal opposite thereto.
(Narrowest width) Indicates a groove, reference numeral 5300b is the first
The groove having the widest width (the widest width) is formed substantially at the center of the length of the optical fiber 311.

A plurality of groove portions 53 of the first optical fiber 311
0 gradually increases the width from the plurality of first end faces E1 that receive the light ray L1 toward the center of the main surface thereof, and-from approximately the center thereof toward the third optical fiber 331. Optical fiber cable (optical fiber sheet) 38 by forming on the main surface so as to decrease gradually
It is possible to make the surface brightness of 0 uniform.

A first gradation pattern in the first and second embodiments of the present invention due to a stepwise change of the distribution density of the plurality of groove portions 530 formed in the first optical fiber 311 in the longitudinal direction thereof; The effect is the same as that of the third gradation pattern of the fourth embodiment due to the stepwise change of the width of the groove portion 530, and it can be said that both are equivalent or equivalent.

Furthermore, the first, second and third gradation patterns may be combined in any combination of two or all.
It can also be formed on the main surface of the optical fiber.

Furthermore, using a plurality of optical fiber sheets,
A laminate in which a plurality of these optical fiber sheets are superposed can be used.

In the drawings for explaining the various embodiments described above, an optical fiber having a light emitting surface (illuminating surface, illuminating section)
The light source is arranged near the light incident ends E1 and E2 of the optical fiber cable having the sheet or the light emitting surface having the light emitting surface, but the light source emits the light when necessary. It can be placed anywhere away from the surface.

That is, an optical fiber sheet, an optical fiber
Extend the sheet part to the vicinity of the place where the linear light source is installed while keeping the sheet state, and along with this, the optical fiber sheet, a substantially linear shape apart from the light emitting surface of the optical fiber sheet part. The light ray incident ends E1 and E2 and the linear light source can be arranged so as to face each other. In this case, it goes without saying that no light leakage means (light emitting portion) is provided in the extension portion of the optical fiber.

Alternatively, a point-like shape is installed at a position apart from the light emitting surface of the optical fiber sheet or the optical fiber sheet portion by extending and converging the light ray incident end portion of the optical fiber sheet or the optical fiber sheet portion. The light source and the light incident end can be arranged so as to face each other. In this case, it goes without saying that no light leakage means (light emitting portion) is provided in the extension portion of the optical fiber.

When an optical fiber is used as the backlight of the liquid crystal display device, the flexibility and bendability of the optical fiber are used to open / close the liquid crystal display device / optical fiber type surface light source such as a notebook computer. It is housed in a display casing, and the light source is housed in a computer main body that has a computing unit, a keyboard, a hard disk, a memory device, etc. installed, and an optical fiber sheet of an optical fiber type surface light source, an optical fiber
It is possible to extend one end of the sheet portion and optically couple the light incident end portion of the extended terminal and the light source in the computer body. In this case, the temperature of the liquid crystal display device rises due to the heat generated by the light source, and display unevenness due to the temperature rise does not occur, and replacement of the light source becomes easy.

The surface light sources of the various embodiments described above scan the laser light in a predetermined gradation pattern with light leakage means such as grooves at predetermined plural points of the first optical fiber portion of the ordinary optical fiber sheet. And hot stamping, and then, as shown in FIGS.
As shown in FIG. 4, FIG. 5, FIG. 7, and FIG. 8, the third optical fiber portion is curved while maintaining a predetermined bending radius R, and the lower surface of the first optical fiber portion and the second optical fiber portion are The upper surface of the first optical fiber section and the upper surface of the second optical fiber section can be bonded and integrated with each other by bending so that the upper surface faces each other and an adhesive member.

Alternatively, the surface light source of each of the above-mentioned various embodiments is provided with a normal optical fiber sheet as shown in FIGS. 1, 2, 4, 5, 7, and 8 and a third optical fiber portion. Is bent while maintaining a predetermined bending radius R, and is bent so that the lower surface of the first optical fiber portion and the upper surface of the second optical fiber portion of an ordinary optical fiber sheet face each other, and an adhesive member is used. The lower surface of the first optical fiber portion and the upper surface of the second optical fiber portion are adhered and integrated, and then light leakage means such as grooves is formed in a predetermined gradation pattern at predetermined plural positions of the first optical fiber portion. It can be formed by scanning laser light, hot stamping, or the like.

The stepped index type optical fiber 31 used in the above-described first to fourth embodiments of the present invention.
Instead of 1, 321 and 331, a graded index (GI) optical fiber having only a core whose refractive index increases toward the axial center and having no cladding can be used. A predetermined portion of the surface of the core of the first GI type optical fiber may be partially deleted or removed to form a plurality of groove portions in the core to serve as a light leakage means (light leakage portion, light emission portion).

Similar to the above-described first to fourth embodiments of the present invention, a plurality of grooves can be formed in a gradation pattern in the core of the first GI type optical fiber.

That is, by using a method such as hot stamping or laser beam irradiation, the depth and width of the plurality of grooves are made constant and the distribution density of the plurality of grooves is changed as in the first and second embodiments. Or changing the depth while keeping the width of the plurality of grooves constant as in the third embodiment, or changing the depth of the plurality of grooves constant as in the fourth embodiment. Change the width of. In this way, a surface light source having a uniform illuminated surface (emission surface, light leakage portion) can be obtained.

Although some embodiments of the present invention have been disclosed in detail above, the present invention is not limited to these embodiments. And, many modifications and equivalent inventions are possible within the spirit of the present invention or the claims of the present invention described in each claim, and the inventions of these modifications and equivalents are also claimed in the present invention. It should be noted that it belongs to the range of.

[0110]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it has the remarkable effect of providing a surface light source device having a large area, light weight, power saving, and uniform surface brightness.

[Brief description of drawings]

FIG. 1 shows a conceptual perspective view of a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view cut along the line 30-31 of FIG.

FIG. 3 is an enlarged cross-sectional view cut along the line 40-41 of FIG.

FIG. 4 shows a conceptual perspective view of a second embodiment of the present invention.

5 is an enlarged cross-sectional view cut along the line 50-51 of FIG.

FIG. 6 is an enlarged cross-sectional view taken along line 60-61 of FIG.

FIG. 7 is a cross-sectional view of a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of the fourth embodiment of the present invention.

[Explanation of symbols]

200 ... Light source 200 ... Reflector 300, 350, 370, 380 ... Surface light source, optical fiber cable 310 ... First light guide portion (illuminating means, light emitting means) 320 ... Second light guide part (light transmission dedicated means) 330 ... Third light guide part (optical coupling means) 311 ... First optical fiber 321 ... Second optical fiber 331 ... 3 optical fibers 311a, 321a and 331a ... Cores 311b, 321b and 331b ... Clad 331c ... Projection 360 ... Transparent layer (light transmitting member) 360a ... Light scattering particles 500, 520, 530 ... Groove (leaking means) 600 ... Adhesive member 600a ... Light-reflecting particles E1 ... First incident end face E2 ... Second incident end face L1 ... First incident light beam L2 ... First incident ray R ... Bending radius

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 6/00 331 G02F 1/13357 G02F 1/13357 F21Y 103: 00 // F21Y 103: 00 F21S 1/00 EF

Claims (19)

[Claims] 1. A second optical fiber part having a first optical fiber part having a first end face and a second optical fiber part having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction. A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is A surface light source device comprising: an optical coupling means for connecting the first optical fiber portion and the second optical fiber portion. 2. A second optical fiber portion having a first optical fiber portion having a first end surface and a second optical fiber portion having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction. A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber section and the second optical fiber section is provided, and the first optical fiber section and the second optical fiber section are arranged vertically adjacent to each other. A surface light source device characterized in that 3. A second optical fiber section having a first optical fiber section having a first end surface and a second optical fiber section, wherein a plurality of optical fibers are arranged substantially parallel to each other in a lateral direction. A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the substantially sheet-like integrated optical fiber sheet,
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion is provided, and a plurality of leaking means (or emitting means) are provided from a plurality of groove portions formed in the first optical fiber portion. A surface light source device characterized by the following. 4. A second optical fiber part having a first optical fiber part having a first end face and a second optical fiber part having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion, and a plurality of leaking means (or emitting means) form a gradation pattern in the first optical fiber portion, A surface light source device which emits a light beam with substantially uniform brightness from substantially the entire surface of the first optical fiber portion. 5. A second optical fiber portion having a first optical fiber portion having a first end surface and a second optical fiber portion having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
The optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a light beam transmitting means, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion, and a plurality of leaking means (or emitting means) form a gradation pattern in the first optical fiber portion, The gradation pattern is one in which the distribution density of the leaking means (or the emitting means) is reduced from substantially the middle of the first optical fiber portion toward both ends thereof, and substantially the first optical fiber portion of the first optical fiber portion. A surface light source device characterized in that light rays are emitted from the entire surface with substantially uniform brightness. 6. A second optical fiber section having a first optical fiber section having a first end surface and a second optical fiber section, wherein a plurality of optical fibers are arranged substantially parallel to each other in a lateral direction, and a first optical fiber section having a second end surface. A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion is provided, and a plurality of leaking means (or emitting means) are provided from a plurality of groove portions formed in the first optical fiber portion. The plurality of grooves form a gradation pattern in the first optical fiber portion, and the gradation pattern reduces the distribution density of the groove portion from approximately the middle of the first optical fiber portion toward both ends thereof. A surface light source device which emits a light beam with substantially uniform brightness from substantially the entire surface of the first optical fiber portion. 7. A second optical fiber portion having a first optical fiber portion having a first end surface and a second optical fiber portion having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, and a first optical fiber portion. A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion is provided, and a plurality of leaking means (or emitting means) are provided from a plurality of groove portions formed in the first optical fiber portion. The plurality of grooves form a gradation pattern in the first optical fiber portion, and the gradation pattern reduces the height of the groove portion from approximately the middle of the first optical fiber portion toward both ends thereof. A surface light source device which emits a light beam with substantially uniform brightness from substantially the entire surface of the first optical fiber portion. 8. A second optical fiber portion having a first optical fiber portion having a first end surface and a second optical fiber portion having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber portion and the second optical fiber portion is provided, and a plurality of leaking means (or emitting means) are provided from a plurality of groove portions formed in the first optical fiber portion. The plurality of groove portions form a gradation pattern in the first optical fiber portion, and the gradation pattern has a width of the groove portion reduced from substantially the middle of the first optical fiber portion toward both ends thereof. The surface light source device is characterized in that light rays are emitted from the substantially entire surface of the first optical fiber portion with substantially uniform brightness. 9. A second optical fiber portion having a first optical fiber portion having a first end surface and a second optical fiber portion having a plurality of optical fibers arranged substantially parallel to each other in a lateral direction, A third optical fiber portion located between the second optical fiber portion and the second optical fiber portion and having a curved portion, the optical fiber sheet having a substantially sheet-like integrated structure is provided.
Of the optical fiber section has a plurality of leaking means (or emitting means) for leaking (or emitting) a light beam, the second optical fiber section has a transmitting means of the light beam, and the third optical fiber section is An optical coupling means for connecting the first optical fiber section and the second optical fiber section, wherein each of the optical fibers of the second optical fiber section and the third optical fiber section has a core and the core; Has a clad having a refractive index lower than that of the core, and the optical fiber of the first optical fiber portion selectively coats the core and the surface of the core and has a refractive index higher than that of the core. 2. A surface light source device having a low clad, wherein the exposed portion of the core not covering the clad is used as the leaking means (or the emitting means). 10. The surface light source device according to claim 1, wherein the first optical fiber section and the second optical fiber section have an adhesive member interposed between them. A surface light source device characterized by being formed. 11. The surface light source device according to claim 1, wherein an adhesive member is interposed between the first optical fiber portion and the second optical fiber portion. And a surface of the surface light source device, wherein the adhesive member is made of a substantially transparent organic resin adhesive in which a plurality of light scattering particles are dispersed. 12. The surface light source device according to claim 1, wherein a mirror member is interposed between the first optical fiber portion and the second optical fiber portion. A characteristic surface light source device. 13. The surface light source device according to claim 1, wherein the first optical fiber portion includes a transparent member that covers the leaking means, and the transparent member is formed of the optical fiber. A surface light source device having a refractive index equal to or higher than that of the core. 14. The surface light source device according to claim 1, wherein the first optical fiber portion is provided with a transparent member that covers the leaking means, and the transparent member is formed of the optical fiber. 1. A surface light source device comprising a substantially transparent organic resin having a refractive index equal to or higher than that of a core. 15. The surface light source device according to claim 1, wherein the first optical fiber portion includes a transparent member that covers the leaking means, and the transparent member is a core of the optical fiber. 1. A surface light source device comprising a substantially transparent organic resin having a refractive index equal to or higher than that, and a plurality of light scattering particles dispersed in the organic resin. 16. The surface light source device according to claim 1, wherein the first optical fiber portion includes a transparent member that covers the leaking means, and the transparent member is a core of the optical fiber. 1. A surface light source device comprising a substantially transparent organic resin having a refractive index equal to or higher than that, and a plurality of light scattering particles made of a pigment dispersed in the organic resin. 17. The surface light source device according to claim 1, and at least one light source, wherein the first end surface and the second end surface are substantially at the same position. A surface light source device which terminates and receives a light beam from the light source. 18. The surface light source device according to claim 1, and at least one light source, wherein the first end surface and the second end surface are adjacent to each other and vertically. A surface light source device, which is arranged and receives a light beam from the light source. 19. The surface light source device according to claim 1, and at least one substantially linear light source, wherein the first end face and the second end face are:
A surface light source device characterized in that it terminates at substantially the same location, is vertically disposed adjacent to each other, and receives light rays from the light source.