JP2006301611A - Light guide plate and light guide plate unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate and a light guide plate unit in which a translucent member such as glass sheet is never stained nor scratched and moreover which are capable of preventing warping. <P>SOLUTION: The light guide plate is equipped with; a glass sheet 1 which is formed to the shape of a flat plate, which propagates light entering from an incident plane 1a ia toward a light-emitting surface, and which has a predetermined prescribed refractive index; and protective members 2 which are adhered on the upper surface and the lower surface of the glass sheet 1 so sa to protect the surfaces, and each of which has a refractive index smaller than that of the prescribed refractive index. The protective members 2 are preferable to be adhered to the glass sheet 1 with adhesives 3 having a lower refractive index than the prescribed refractive index predetermined. Moreover, the light guide plate is preferably equipped with side face protective members 4 which are adhered so as to protect a pair of side faces other than the incident plane 1a and the light-emitting surface, and each of which has a refractive index smaller than the prescribed refractive index. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light guide plate that propagates light and a light guide plate unit.

  In order to transmit the light output from the optical fiber to another optical fiber, a light distributor including a light-transmitting member capable of propagating the light emitted from the optical fiber, for example, a glass sheet, is known. The glass sheet provided in the light distributor can emit light that is incident from one end face to the other end face while being totally reflected in the glass sheet. Therefore, the exit side optical fiber arranged on the exit surface can receive the emitted light and propagate the received light.

By the way, this glass sheet is generally very small. For example, the total length is 5.4 mm, the thickness is 0.1 mm to 0.3 mm, and the width is 0.52 mm. Therefore, the handling is very inconvenient. Therefore, as described in Japanese Patent Application Laid-Open No. 2003-255177 (Patent Document 1), a support base is brought into close contact with one surface of a flat plate-like light-transmitting medium corresponding to a glass sheet, thereby transmitting the light. It is considered to make the medium easy to handle.
JP 2003-255177 A

  However, in the technique described in Japanese Patent Application Laid-Open No. 2003-255177, the support base is not in close contact with one surface of the translucent medium corresponding to the glass sheet. In the middle, the total reflection surface may become dirty or scratched. As described above, when the total reflection surface becomes dirty or scratched, there is a problem that the light propagation efficiency is lowered. The glass sheet is made of a very thin glass material. Warpage may occur when the glass sheet is fixed to the light distributor, or warpage may occur due to deterioration over time.

  Then, this invention aims at implement | achieving the light-guide plate and light-guide plate unit which can prevent that a translucent member, such as a glass sheet, becomes dirty or a damage | wound, and also generate | occur | produces curvature. .

  In order to solve the above-described problems, the light guide plate of the present invention is a flat plate member having a predetermined specified refractive index, and faces light incident from an incident surface which is a side surface to the incident surface. And a protective member having a refractive index smaller than the prescribed refractive index, which is bonded so as to protect the upper and lower surfaces of the transparent member. ing.

  According to this invention, the protective member is bonded to the translucent member so as to protect the upper surface and the lower surface, and the refractive index of the protective member is smaller than the specified refractive index of the translucent member. As a result, the upper and lower surfaces of the translucent member do not get dirty or scratched. Further, it is possible to prevent the light transmitting member from warping due to deterioration over time, or to prevent the light transmitting member from warping during manufacturing of the light guide plate, and the propagation efficiency of light propagating through the light transmitting member. Can be improved. Further, by adhering the protective member to the upper and lower surfaces of the translucent member, the light guide plate can be made into a block shape, and the handleability during manufacturing can be improved.

  Moreover, it is preferable that the said protective member of the light-guide plate of this invention is adhere | attached through the said translucent member through the adhesive agent which has a refractive index smaller than the said prescribed refractive index.

  According to this invention, the translucent member and the protective member can be bonded via the adhesive having a refractive index smaller than the specified refractive index, and the propagation efficiency of light propagating in the translucent member is improved. Can be made.

  The light guide plate of the present invention further includes a side surface protection member having a refractive index smaller than the specified refractive index, which is bonded to protect a pair of side surfaces excluding the incident surface and the exit surface. It is preferable.

  According to this invention, the side surface protection member having a refractive index smaller than the specified refractive index can be bonded so as to protect the pair of side surfaces of the translucent member excluding the entrance surface and the exit surface. The propagation efficiency of light propagating in the sex member can be improved.

  Moreover, it is preferable that the said side surface protection member of the light-guide plate of this invention is adhere | attached through the said translucent member through the adhesive agent which has a refractive index smaller than the said prescribed refractive index.

  According to this invention, the translucent member and the side surface protection member can be bonded via the adhesive having a refractive index smaller than the specified refractive index, and the propagation efficiency of light propagating in the translucent member can be improved. Can be improved.

  The light guide plate of the present invention is preferably used as a light distribution element that distributes light incident from the incident surface and emits the light to a plurality of light guide members connected to the output surface.

  Further, in the light guide plate of the present invention, at least one layer of the protective member that protects the upper surface and the lower surface of the translucent member, to which the light guide member formed by forming a core between the clads on the emission surface is connected. The thickness is preferably the same as the cladding layer thickness. In this case, when the light guide plate and the light guide member are placed on the substrate and connected, the thickness of the protective member of the light guide plate and the thickness of the clad layer of the light guide member are the same. Since the positions of the cores of the optical member and the light guide member coincide with each other, the optical axis can be easily aligned.

  Here, “the thickness of at least one of the protective members is the same as the thickness of the cladding” is not limited to the case where the thickness of the protective member is the same as the thickness of the cladding. This includes the case where the thickness is substantially the same as the layer thickness of the cladding.

  In addition, the light guide plate of the present invention is preferably an optical fiber in which a light guide member connected to the emission surface forms a core in the clad.

  Moreover, the light guide plate of this invention WHEREIN: It is preferable that the said protective member is thickly formed in the up-down direction compared with the said translucent member. In this case, not only can the surface of the translucent member be covered and protected, but also the mechanical strength of the light guide plate can be improved. For this reason, damage at the time of handling at the time of manufacture can be prevented.

  The light guide plate unit of the present invention includes the light guide plate and a holder that holds the light guide plate.

  According to this invention, the protective member is bonded to the translucent member so as to protect the upper surface and the lower surface, and the refractive index of the protective member is smaller than the specified refractive index of the translucent member. This prevents the upper and lower surfaces of the translucent member from being soiled or scratched, prevents warping due to deterioration over time, and the propagation efficiency of light propagating through the translucent member. Can be improved. Furthermore, the light guide plate itself can be easily handled by holding the light guide plate with the holder.

  In the present invention, the upper and lower surfaces of the translucent member are not soiled or scratched, and the translucent member is warped due to deterioration over time, or the translucent member is warped during manufacture of the light guide plate. This can be prevented.

  In addition, it is possible to improve the propagation efficiency of light propagating through the translucent member by preventing the translucent member from warping during the manufacture of the light guide plate.

  The present invention can be readily understood by considering the following detailed description with reference to the accompanying drawings shown for the embodiments. Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view of a light guide plate 10 of the present embodiment. As shown in FIG. 1, the light guide plate 10 is configured to include a glass sheet 1 and a protective member 2 which are light transmissive members. The glass sheet 1 is formed of a glass material having a refractive index of 1.62, for example, in the form of a flat plate having a thickness of 0.1 mm. The glass sheet 1 is formed in a rectangular shape so as to have at least an incident surface 1a and an exit surface formed at a position facing the incident surface 1a. The glass sheet 1 is made of glass so as to prevent dirt from the outside from being attached or damaged, and to prevent the glass sheet 1 from warping and to facilitate the handling of the glass sheet 1. A protective member 2 is bonded to the upper and lower surfaces of the sheet 1. The protective member 2 is made of, for example, a flat glass material having a thickness of 0.5 mm, and is made of a material having a refractive index (about 1.5) smaller than the refractive index 1.62 of the glass sheet 1. Become.

  The light guide plate 10 configured as described above can receive light from the incident surface 1a formed on the side surface of the glass sheet 1 and emit light from the output surface formed at a position facing the incident surface 1a. As can be done, the incident light is totally reflected in the glass sheet 1 and propagates. The glass sheet 1 is preferably S-TIM2 manufactured by OHARA, and the protective member 2 is preferably BK7 manufactured by SCHOTT.

  The light guide plate 10 has a single rectangular parallelepiped obtained by adhering the glass material that is the base of the protective member 2 to the upper and lower surfaces of the glass material that is the base of the glass sheet 1. ) Is obtained by cutting. Since the cut surface is roughened by being cut, polishing is required.

  Next, a front view of the light incident plate 1 on the incident surface 1a side is shown in FIG. As shown in FIG. 2, the light guide plate 10 has an incident surface 1 a formed on an end surface thereof. In the present embodiment, the width of the incident surface 1a of the light guide plate 10 in the front view shown in FIG. 2 is an extremely narrow width of about 0.52 mm.

  FIG. 3 shows a side view of the light guide plate 10. As shown in FIG. 3, a side surface 1 b is formed on the glass sheet 1 of the light guide plate 10. In the present embodiment, the width of the side surface 1b is about 5.2 mm.

  As shown in FIG. 4, the above-described light guide plate 10 is configured by bonding the glass sheet 1 and the protection member 2 using an adhesive 3. FIG. 4 is a side sectional view of the light guide plate 10 on the bonding surface bonded by the adhesive 3. FIG. 4 shows only one half of the light guide plate 10 for convenience of explanation. As shown in FIG. 4, the glass sheet 1 and the protection member 2 are bonded using an adhesive 3. Here, it is essential that the adhesive 3 has a refractive index smaller than the refractive index of the glass sheet 1, and it is preferable that the adhesive 3 be larger than the refractive index of the protective member 2. For example, the refractive index of the adhesive 3 is preferably 1.54 or less in consideration of the efficiency of total reflection of light in the glass sheet 1. The adhesive 3 is preferably an optical adhesive NOA68 manufactured by Noland.

  Thus, the adhesive 3 has a refractive index smaller than the refractive index of the glass sheet 1, so that the light propagated to the glass sheet 1 is as shown by the arrow A in FIG. Is efficiently reflected at the plane between. Even if light propagates in the adhesive 3, the refractive index of the adhesive 3 is larger than the refractive index of the protective member 2. Therefore, as shown by the arrow B in FIG. The light can be reflected on the surface between the adhesive 3 and the protective member 2, and the reflected light is propagated back into the glass sheet 1.

  Next, a modified example of the light guide plate 10 will be described. FIG. 5 is a front view of a light guide plate 10a which is a modified example. As shown in FIG. 5, the light guide plate 10 a has the side surface protection member 4 that can protect the side surface 1 b of the light guide plate 10 bonded to the side surface (including the side surface 1 b) of the glass sheet 1. More specifically, the protective member 2 having the same width as the glass sheet 1 is bonded to the upper surface and the lower surface of the glass sheet 1. And the adhesive agent 3 is used so that the side surface of the glass sheet 1 can be protected with the side surface protection member 4 having a thickness obtained by adding the thickness of the glass sheet 1 and the thickness of the pair of protection members 2. Glued. Thereby, the light leaking from the side surface 1b can be reflected into the glass sheet 1, and further, the light propagation efficiency can be increased, and the light guide plate 10a can be formed from a sheet shape to a block shape. Handling can be facilitated.

  Furthermore, another modified example will be described. FIG. 6 is a front view of a light guide plate 10b which is another modification. As shown in FIG. 6, one protective member 2 is arranged so that one end face thereof is in contact with one side protective member 4. Further, the one side surface protection member 4 is arranged so that one end surface thereof is in contact with the protection member 2 different from the one protection member 2. Further, the other protective member 2 is disposed such that one end surface thereof is in contact with the side surface protecting member 4 different from the one side surface protecting member 4. The other side surface protection member 4 is arranged so that one end surface thereof is in contact with the one protection member 2. As described above, the protective member 2 is disposed such that one end surface thereof is in contact with the side surface protection member 4 and the side surface protection member 4 is disposed so that one end surface thereof is in contact with the protection member 2. The protective member 2 and the side surface protective member 4 are protected. By disposing the protection member 2 and the side surface protection member 4 in this way, the light guide plate 10b can efficiently transmit light and the light guide plate 10b, as in the light guide plate 10a of the above-described modification. The cross section can be formed in a rectangular shape, and the handling thereof can be facilitated.

  The light guide plate unit 20 that holds the light guide plate 10 (or the light guide plate 10a or 10b) configured as described above will be described. FIG. 7 is a perspective view of the light guide plate unit 20. The light guide plate unit 20 includes a holder 30 that holds the light guide plate 10 and the light guide plate 10. Since the light guide plate 10 is extremely small as described above, the holder 30 holds the light guide plate 10 in order to make it easy to handle and to prevent damage from external impacts. The handling is made easy. Specifically, the holder 30 is formed in a columnar shape, and a notch portion is formed on one surface of the outer peripheral portion so that the light guide plate 10 can be attached. The light guide plate 10 is held so that the entrance surface and the exit surface of the light guide plate 10 are exposed at the end surface of the holder 30.

  Next, an example of how to use the light guide plate 10 of the present embodiment will be described.

  FIG. 8 is a plan view showing a connection state between the light guide plate and the light guide member, and FIG. 9 is a side view showing a connection state between the light guide plate and the light guide member.

  As shown in FIG. 8, the light guide plate 10 is placed on the holding substrate 60, one optical fiber 50 is connected to the input side of the light guide plate 10, and a plurality of optical fibers 40 are connected to the output side. Yes. The light guide plate 10 functions as an optical distributor for the optical signal input from the optical fiber 50 to the plurality of optical fibers 40 on the output side. The optical fibers 40 and 50 function as a light guide member that guides an optical signal.

  As shown in FIG. 9, the optical fibers 40 and 50 are connected to the light guide plate 10 so that the optical axis of the translucent member 1 of the light guide plate 10 matches the optical axes of the cores 41 and 51 of the optical fibers 40 and 50. Has been. At this time, the layer thickness of the protective member 2 below the light guide plate 10 is preferably the same as the layer thickness of the cladding 52 of the optical fiber 50 and the layer thickness of the cladding 42 of the optical fiber 40. In this case, by simply placing the light guide plate 10 and the optical fibers 40 and 50 on the holding substrate 60 and coming into contact therewith, these optical axes can be easily aligned.

  For example, when the clad diameter in the optical fibers 40 and 50 is 125 μm, the core diameter is 50 μm, and the clad layer thickness is 37.75 μm, the layer thickness of the protective member 2 on the lower side of the light guide plate 10 is preferably 37.75 μm. At this time, the protective member 2 may have a layer thickness of approximately 37.75 μm ± 20% and substantially the same thickness as the cladding layer.

  Further, when the clad diameter in the optical fibers 40 and 50 is 500 μm, the core diameter is 120 μm, and the clad layer thickness is 190 μm, the layer thickness of the protective member 2 on the lower side of the light guide plate 10 is preferably 190 μm. At this time, the protective member 2 may have a layer thickness of about 190 μm ± 20% and substantially the same thickness as the cladding layer.

  Below, the effect of the light-guide plate 10 and the light-guide plate unit 20 of this embodiment is demonstrated. In the light guide plate 10 of the present embodiment, the protective member 2 is bonded to the glass sheet 1 that is a light transmissive member so as to protect the upper surface and the lower surface, and the refractive index of the protective member 2 is set to the glass sheet 1. By making the refractive index smaller than the prescribed refractive index, the upper and lower surfaces of the glass sheet 1 are not soiled or scratched. In addition, it is possible to prevent the glass sheet 1 from warping due to deterioration over time, or to prevent the glass sheet 1 from warping when the light guide plate 10 is manufactured. Thereby, for example, when the light emitted from the optical fiber arranged on the incident surface of the glass sheet 1 is incident and the incident light is propagated toward the emitting surface formed to face the incident surface, the glass The propagation efficiency of light propagating through the sheet 1 can be improved. Therefore, light can be efficiently incident on one or a plurality of optical fibers arranged on the exit surface, and accurate signal transmission can be realized.

  In addition, the light guide plate 10 of the present embodiment can bond the glass sheet 1 and the protective member 2 via the adhesive 3 having a refractive index smaller than the specified refractive index, and light that propagates in the glass sheet 1. The propagation efficiency can be improved.

  Moreover, the light guide plate 10 of this embodiment adhere | attaches the side surface protection member 4 which has a refractive index smaller than a prescription | regulation refractive index so that the pair of side surface 1b except the entrance plane 1a and the output surface in the glass sheet 1 may be protected. The propagation efficiency of light propagating through the glass sheet 1 can be improved.

  Moreover, the light guide plate 10 of this embodiment can adhere the glass sheet 1 and the side surface protection member 4 through the adhesive 3 having a refractive index smaller than the specified refractive index, and propagates through the glass sheet 1. Light propagation efficiency can be improved.

  In addition, the light guide plate unit 20 of the present embodiment has a protective member 2 bonded to the glass sheet 1 so as to protect the upper surface and the lower surface thereof, and the refractive index of the protective member 2 is determined to be the prescribed refraction of the glass sheet 1. By making it smaller than the rate, it is possible to prevent the upper and lower surfaces of the glass sheet 1 from becoming dirty or scratched, to prevent warping due to aging, and to propagate through the translucent member. The propagation efficiency of light can be improved. Furthermore, the light guide plate 10 itself can be easily handled by holding the light guide plate 10 with the holder 30.

1 is a perspective view of a light guide plate 10 according to an embodiment of the present invention. 4 is a front view of the light guide plate 10 on the incident surface 1a side. FIG. 3 is a side view of the light guide plate 10. FIG. 3 is a side cross-sectional view of the light guide plate 10 on a bonding surface bonded by an adhesive 3. FIG. It is a front view of the light-guide plate 10a which is a modification. It is a front view of the light-guide plate 10b which is another modification. 3 is a perspective view of a light guide plate unit 20. FIG. It is a top view which shows the light guide plate 10, an optical fiber, and a connection state. It is a side view which shows the light guide plate 10 and an optical fiber, and a connection state.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Glass sheet, 1a ... Incident surface, 1b ... Side surface, 2 ... Protection member, 3 ... Adhesive, 4 ... Side surface protection member, 10 ... Light guide plate, 10a ... Light guide plate, 10b ... Light guide plate, 20 ... Light guide plate unit 30 ... Holder.

Claims (9)

A flat plate-like member having a prescribed refractive index determined in advance, and a light-transmitting member that propagates light incident from an incident surface that is a side surface toward an exit surface formed opposite to the incident surface; ,
A protective member having a refractive index smaller than the prescribed refractive index bonded to protect the upper and lower surfaces of the translucent member;
A light guide plate comprising:   The light guide plate according to claim 1, wherein the protective member is bonded to the translucent member via an adhesive having a refractive index smaller than the specified refractive index.   The light guide plate according to claim 1, further comprising a side surface protection member having a refractive index smaller than the specified refractive index, which is bonded so as to protect a pair of side surfaces excluding the incident surface and the emission surface.   The light guide plate according to claim 3, wherein the side surface protection member is bonded to the translucent member via an adhesive having a refractive index smaller than the specified refractive index.   It functions as a light distribution element which distribute | divides the light which injected from the said incident surface, and each radiate | emits with respect to the several light guide member connected to the said output surface. The light guide plate described in 1. A light guide member formed by forming a core between the clads on the emission surface is connected,
The thickness of at least one of the protective members protecting the upper and lower surfaces of the translucent member is the same as the thickness of the cladding;
The light guide plate according to claim 1, wherein:   The light guide plate according to claim 6, wherein the light guide member is an optical fiber having a core formed in a clad.   The light guide plate according to any one of claims 1 to 7, wherein the protective member is formed to be thicker in the vertical direction than the translucent member. The light guide plate according to any one of claims 1 to 8,
A holder for holding the light guide plate;
A light guide plate unit comprising:

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