JP2011151440A - Linear light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear light source device capable of suppressing a change from a light distribution in initial lighting even if turning on-and-off a light is repeated for a light source, while thermal expansion of a light guide is permitted. <P>SOLUTION: The linear light source device according to this invention includes a rod-like light guide, a light source prepared at both ends of the light guide, and a support prepared along with the longitudinal direction of the light guide for fixing the light source while supporting the light guide. In addition, the linear light source device has a fixing member for fixing the support and the light guide to one place in the longitudinal direction of the light guide. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a linear light source device used as an illumination light source of an image reading apparatus used for a facsimile, a copying machine, an image scanner, a barcode reader, and the like.

  Conventionally, as an image reading apparatus such as a facsimile, a linear light source device described in Patent Document 1 has been known.

FIG. 10 is an explanatory diagram of a conventional linear light source device 101.
FIG. 10A is an exploded perspective view of each member. FIG. 10B is a cross-sectional view orthogonal to the longitudinal direction of the light guide 131 in a state where the members of FIG.

The linear light source device 101 fixes a cylindrical light guide 131, light sources 121 and 122 opposed to both ends in the longitudinal direction of the light guide 131, and fixes the light sources 121 and 122 and holds the light guide 131. And a support 142 to be provided.
The light sources 121 and 122 include light emitting diodes.
Light from the light sources 121 and 122 is incident from both ends of the light guide 131 and is sequentially reflected by reflection surfaces provided on the outer surface of the light guide 131. Since this reflection surface is provided along the longitudinal direction of the light guide, the light from the light sources 121 and 122 is sequentially reflected along the longitudinal direction of the light guide 131, and the exit surface of the light guide 131. The linear light is emitted from. On the support 142, the lamp house 111 surrounding the light guide 131 is disposed. The lamp house 111 is provided with an opening 112, and linear light from the light guide 131 is emitted from the opening 112.

  Some linear light source devices 101 according to the related art are described in Patent Document 2 as those in which bending of the light guide 131 is suppressed.

FIG. 11 is an explanatory diagram of the linear light source device 201 described in Patent Document 2. FIG.
FIG. 11 is a cross-sectional view orthogonal to the longitudinal direction of the light guide 231.

The linear light source device 201 of Patent Document 2 is provided with a pair of projecting portions 232 that project from a rod-shaped light guide 231 in a direction perpendicular to the longitudinal direction of the light guide 231.
A support body 211 is disposed along the longitudinal direction of the light guide body 231, and the light guide body 231 is placed on the support body 211. The support 211 engages with the protrusion 232 so as to restrict the rotation with respect to the rotation direction about the longitudinal direction of the light guide 231, and holds the light guide 231 in a fixed manner.
Further, the linear light source device 201 of Patent Document 2 is provided with first and second light turning surfaces 241 and 242 along the longitudinal direction of the light guide 231. The light diverting surfaces 241 and 242 are formed with a large number of mountain-shaped concave and convex grooves arranged in parallel in the longitudinal direction, and the light reflected by the light diverting surfaces 241 and 242 is incident on the light diverting surfaces 241 and 242. Opposing sections are emitted from a substantially semicircular exit surface.

JP 09-163079 A JP 2008-216409 A

As in Patent Document 1, when light sources 121 and 122 are provided at both ends of the light guide 101 and light from the light sources 121 and 122 is obtained as linear light through the light guide 131, the light sources 121 and 122 are turned on. -When the light is turned off repeatedly, the light distribution of the linear light from the light guide 131 may change. Specifically, this will be described with reference to FIG.
FIG. 12 shows the light distribution in the longitudinal direction of the linear light source device 101 shown in FIG. The vertical axis in FIG. 12 indicates the relative intensity based on the intensity of light at the center of the light guide 131, and the horizontal axis in FIG. 12 indicates the length of the light guide 131 in the longitudinal direction. Yes.
For example, when the linear light source device 101 is designed to have a light distribution that is line symmetric in the direction perpendicular to the longitudinal direction of the light guide 131 at the center of the light guide 131, When the light distribution immediately after lighting is measured, it has a light distribution as shown in FIG. FIG. 12B shows the result of measuring the light distribution after the linear light source device 101 was turned on for 30 minutes, then turned off for 30 minutes, and measured again immediately after turning on. Further, FIG. 12C shows the result of measuring the light distribution after the light was turned on for 30 minutes, turned off for 30 minutes, and turned on again. In this way, the light distribution distribution immediately after lighting a total of three times is the light distribution distribution of A, B, and C, respectively, and each light distribution distribution shows a different one. In C, the light distribution that is line-symmetric with respect to the center of the light guide 131, which was in the initial design of the linear light source device 101, has been lost.

The reason why the light distribution of the linear light from the linear light source device 101 is different by repeatedly turning on and off in this way will be described with reference to FIG.
FIG. 13 is a diagram illustrating a process of expansion / contraction of the light guide 131. FIG. 13A illustrates a state in which the light sources 121 and 122 are not lit, and FIG. 122 is turned on and the light guide 131 is expanded, and FIG. 13C is a state where the light sources 121 and 122 are turned off and the light guide 131 is contracted.
The light guide 131 is heated and expands by absorbing light from the light sources 121 and 122. Since the support 142 allows the light guide 131 to expand, the support 142 does not have a portion to which the light guide 131 is fixed. When the light guide 131 expands, the portion serving as a fulcrum is the support 142. Not determined against. Therefore, for example, as shown in FIG. 13B, when the fulcrum F1 when the light guide 131 is expanded is located at the center in the longitudinal direction of the light guide 131, the light guide 131 uses the center as a fulcrum. Swells left and right. Next, even when contracting, the portion serving as the fulcrum is not fixed with respect to the support base. Therefore, for example, as shown in FIG. 13C, the fulcrum when the light guide 131 contracts is the end of the light guide 131 in the longitudinal direction (on the left side of the light guide 131 in FIG. 13C). When positioned at the end), the light guide 131 contracts with the end serving as a fulcrum F2. At this time, the fulcrum F1 at the time of expansion and the fulcrum F2 at the time of contraction are different, so that the light guide 131 in FIG. The ratio of the distance L71 to the distance L72 from the other end surface of the light guide 131 to the other light source 122 (L71: L72) after the light guide 131 in FIG. The distance L91 from one end face of the light source to the one light source 121 and the distance L92 from the other end face of the light guide 131 to the other light source 122 (L91: L92) do not match. For this reason, the linear light source device 101 according to the related art repeats expansion and contraction by repeatedly turning on and off, and the light distribution of the light distribution by the fact that the fulcrum at the time of expansion and the fulcrum at the time of contraction do not coincide with each other. It is presumed that there was a problem that would change.

  In order to prevent the light distribution from changing, it is conceivable to fix both ends of the light guide 131. However, the light guide 131 is not allowed to expand, leading to eccentricity of the light guide 131. .

  As described above, if the light distribution changes when the light guide is repeatedly turned on and off, the illuminance on the reading medium, for example, original paper is partially insufficient, or the color balance during color reading is reduced. The problem of lack of.

  Accordingly, an object of the present invention is to provide a linear light source device that suppresses a change in light distribution at the beginning of lighting even when the light source is repeatedly turned on and off while allowing thermal expansion of the light guide. .

A linear light source device according to a first aspect of the present invention is a rod-shaped light guide, light sources provided at both ends of the light guide, and provided along the longitudinal direction of the light guide. A linear light source device comprising: a support for fixing the light source; and a fixing means for fixing the support and the light guide at one location in the longitudinal direction of the light guide. It is characterized by that.
In the linear light source device according to a second aspect of the present invention, in the first aspect, the light guide is provided with a protrusion that protrudes in a direction perpendicular to the longitudinal direction, and the support is a protrusion that faces the protrusion. The fixing means is configured to fix the protruding portion of the support and the protruding portion opposing portion of the light guide.
The linear light source device according to a third invention is characterized in that, in the first invention or the second invention, the position where the fixing portion is provided is the center in the longitudinal direction of the light guide.

The linear light source device according to the first and second inventions suppresses the change in the light distribution at the beginning of lighting in the longitudinal direction of the light guide, even if the light source is repeatedly turned on and off, due to the above characteristics. it can.
A linear light source device according to a third aspect of the present invention has a light distribution distribution when the light guide at the beginning of lighting is not expanded and a light distribution distribution when the light guide after lighting is expanded due to the above characteristics. Can be approximated.

It is explanatory drawing of the linear light source device which concerns on a 1st Example. It is explanatory drawing of the linear light source device which concerns on a 1st Example. It is explanatory drawing of the linear light source device which concerns on a 2nd Example. It is explanatory drawing of the linear light source device which concerns on a 3rd Example. It is explanatory drawing of the effect of a 3rd Example. It is explanatory drawing of the linear light source device which concerns on a 4th Example. It is explanatory drawing of the linear light source device which concerns on a 5th Example. It is explanatory drawing of the linear light source device which concerns on a 6th Example. It is explanatory drawing of an experimental result. It is explanatory drawing of the linear light source device which concerns on the past. It is explanatory drawing of the linear light source device which concerns on the past. It is explanatory drawing of an experimental result. It is explanatory drawing of a subject.

1 and 2 are explanatory views of a linear light source device 1 according to a first embodiment of the present invention.
FIG. 1 is a perspective view showing each member of the linear light source device 1 in an exploded state.
2A is a side view seen from the side of the light guide 3 in a state where the members of the linear light source device 1 of FIG. 1 are assembled. FIG. 2B is a side view of FIG. It is sectional drawing (AA sectional drawing of Fig.2 (a)) orthogonal to the longitudinal direction of the light guide 3 of FIG. In FIG. 2, the light source fixing member 53 omitted in FIG. 1 is illustrated.

  The linear light source device 1 includes a rod-shaped light guide 3, light sources 2 a and 2 b disposed at both ends of the light guide 3, and a support 5 on which the light guide 3 is placed along its longitudinal direction. In addition, a fixing means 7 for fixing the light guide 3 and the support 5 is provided at one place in the longitudinal direction of the light guide 3.

The rod-shaped light guide 3 includes an emission surface 32 having a semicircular cross section, and the emission surface 32 is formed along the longitudinal direction of the light guide 3.
As the member constituting the light guide 3, a member that transmits visible light is used. For example, translucent glass such as soda lime glass, aluminosilicate glass, borosilicate glass, and barium glass is used. Translucent resins such as acrylic resins, polycarbonate resins, cyclic polyolefin resins such as COC and COP, polyolefin resins such as olefin maleimide copolymers, and polyester-based transparent resins are used.

A diffusion sheet 4 extending along the longitudinal direction of the light guide 3 is disposed on the opposite side of the light guide 3 from the emission surface 32.
A support 5 is disposed on the back side of the diffusion sheet 4, and the diffusion sheet 4 is sandwiched between the light guide 3 and the support 5.

The support 5 extends along the longitudinal direction of the light guide 3 and includes a hook-like surface 51 on which the diffusion sheet 4 is disposed. The light guide 3 is placed via the diffusion sheet 4.
As a member constituting the support body 5, resin members such as engineer plastics such as PC, PBT, PPS and super engineer plastics are used, and Al, Mg, Al, Mg, Si, Al, Cu are used. Aluminum extruded material and cast material are used.

  As shown in FIG. 2, the light guide 3, the diffusion sheet 4, and the support 5 are fixed at one place by a fixing means 7 such as an inorganic adhesive 6 in the longitudinal direction of the light guide 3.

The light sources 2a and 2b are opposed to both end faces 33 and 34 in the longitudinal direction of the light guide 3, respectively. The light sources 2a and 2b include a light emitting diode (not shown), a substrate 21 provided with the light emitting diode, and a sealing body 23 that seals the light emitting diode.
The light sources 2 a and 2 b are arranged separately from the end surfaces 33 and 34 of the light guide 3 so that a gap is provided between the light sources 2 a and 2 b.

  A light source fixing body 53 fixed to the support 5 is provided on the back surface of the substrate 21, and the light sources 2 a and 2 b at both ends are fixed to the support 5 by the light source fixing body 53.

  The above-described linear light source device 1 feeds linear emitted light along the longitudinal direction of the light guide 3 from the emission surface 32 of the light guide 3 by feeding power to the light sources 2a and 2b from a power supply device (not shown). Let it emit. A process from when the linear light source device 1 emits light from the emission surface 32 to extinguish the light and then emits light again will be described.

The light sources 2a and 2b emit light when supplied with power. At this time, since the light sources 2a and 2b are arranged on both end faces 33 and 34 of the light guide 3, light enters from both end faces 33 and 34. The light guide 3 guides the light from the light sources 2a and 2b inside, reflects the light to the diffusion sheet 4, and emits the light from the emission surface 32 (the light from the emission surface 32 is turned on for the first time). Linear light of time).
When the light from the light sources 2a and 2b continues to enter, the light guide 3 is heated and expands by absorbing the light from the light sources 2a and 2b. Since the fixing means 7 is provided at one place in the longitudinal direction of the light guide 3, a fulcrum when the light guide 3 expands is determined by the fixing means 7 and expands with respect to the support 5. A gap is provided between the other end surface 34 of the light guide 3 and the other light source 2b, and the light guide 3 is allowed to expand by this gap.
In addition, although the support body 5 is also heated and expanded, since the light from the light sources 2 a and 2 b is not directly irradiated, the expansion amount of the support body 5 is smaller than the expansion amount of the light guide 3.

  When the power supply to the light sources 2a and 2b is stopped, the linear light source device 1 stops emitting light from the emission surface 32 of the light guide 3 and is turned off. At this time, the light guide 3 is cooled and starts contracting. When the light guide 3 contracts, the support 5 contracts with the fixing means 7 as a fulcrum. The contracted light guide 3 returns to the position of the light guide 3 before expansion because the fulcrum during expansion and the fulcrum during contraction are at the same position with respect to the support 5.

  After the light guide 3 contracts, the linear light source device 1 starts to supply power to the light sources 2a and 2b again and emits light from the emission surface 32 (the light from the emission surface 32 is emitted for the second time). Linear light when lighting). The light distribution of the second linear light is such that the light guide 3 returns to the position before expansion relative to the support 5, and the support 5 passes through the light source fixing body 53 to guide the light guide 3. Since the positional relationship between the light source 2a and the light source 2b is restored before the expansion, it matches the light distribution of the first linear light.

  Therefore, the linear light source device 1 according to the first embodiment provides a gap between the light guide 3 and the light sources 2a and 2b, thereby allowing the light guide 3 to expand while allowing the light guide 3 to expand. Is fixed at one place with respect to the support 5, even if the light sources 2a and 2b are repeatedly turned on and off, the change in the light distribution at the beginning of lighting can be suppressed.

  In the first embodiment, the example in which the fixing means 7 is provided on the outer surface of the light guide 3 has been shown. However, as shown in Patent Document 2, the fixing means 7 in the case where the light guide 3 is provided with the protruding portion 35. The position where the position is provided will be described using the second embodiment.

FIG. 3 is an explanatory diagram of the linear light source device 1 according to the second embodiment of the present invention.
FIG. 3A is a perspective view showing each member of the linear light source device 1 in an exploded state.
FIG.3 (b) is the perspective view which showed the state which assembled each member of the linear light source device 1 of Fig.3 (a).
FIG. 3 (c). It is sectional drawing orthogonal to the longitudinal direction of the light guide 3 of FIG.3 (b) (FIG.3 (b) BB sectional drawing).
FIG. 3D is an enlarged view of a portion surrounded by a dotted circle in FIG.
In FIG. 3C, the light source fixing member 53 omitted in FIGS. 3A, 3B, and 3D is shown.
In FIG. 3, the same components as those illustrated in FIGS. 1 and 2 are denoted by the same reference numerals.

3 shows that the light guide 3 is provided with a protrusion 35, the support 5 is provided with a protrusion facing portion 52, and the fixing means 7 is provided between the protrusion 35 of the light guide 3 and the support 5. It differs from FIG. 1 and FIG. 2 by the point provided in the protrusion part opposing part 52. FIG.
As a description of the second embodiment of FIG. 3, the description of the parts common to those in FIGS. 1 and 2 will be omitted, and the different parts will be described.

  As shown in FIG. 3C, the light guide 3 is provided with a protruding portion 35 that protrudes in a direction perpendicular to the longitudinal direction. As shown in FIG. 3B, the protruding portion 35 is provided so as to extend along the longitudinal direction of the light guide 3.

  A protruding portion facing portion 52 that faces the protruding portion 35 of the light guide 3 is provided on the side of the bowl-shaped surface 51 of the support 5. As shown in FIG. 3B, the protruding portion facing portion 52 is provided so as to extend along the longitudinal direction of the light guide 3.

  The light guide 3 is placed on the bowl-shaped surface 51 of the support 5 via the diffusion sheet 4, and the protrusion 35 of the light guide 3 and the protrusion facing portion 52 of the support 5 are shown in FIG. As shown to (c), it arrange | positions so that it may mutually contact | abut, For example, it fixes by the fixing means 7 like the inorganic adhesive agent 6 so that this contact state may be maintained.

  As in the second embodiment of FIG. 3, even if the fixing means 7 is provided in the protruding portion 35 of the light guide 3 and the protruding portion facing portion 52 of the support 5, the light guiding is performed as in the first embodiment. By providing a space between the body 3 and the light sources 2a and 2b, the light guide 3 is fixed to the support 5 while allowing the light guide 3 to expand, so that the light source 2a , 2b can be turned on and off repeatedly to suppress a change in light distribution at the beginning of lighting.

  In the first and second embodiments, the fixing means 7 is provided at the end in the longitudinal direction of the light guide 3. However, the third embodiment will be described as an example in which fixing means is provided in addition to the end.

FIG. 4 is an explanatory diagram of the linear light source device 1 according to the third embodiment of the present invention.
4 (a) is a perspective view of the linear light source device 1, and FIG. 4 (b) is an enlarged view of a portion surrounded by a dotted circle in FIG. 4 (a).
In FIG. 4, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

FIG. 4 differs from FIG. 3 in that the fixing means 7 is provided at the center in the longitudinal direction of the light guide 3.
As a description of the third embodiment of FIG. 4, the description of the parts common to FIG. 3 will be omitted, and the different parts will be described.

The fixing means 7 is provided at the center in the longitudinal direction of the light guide 3.
Even if the fixing means 7 is provided in the center in the longitudinal direction of the light guide 3 as in the third embodiment of FIG. 4, the light guide 3 and the light sources 2a and 2b are not provided as in the third embodiment. By providing an air gap between them, the light guide 3 is fixed to the support 5 at one location while allowing the light guide 3 to expand, so that the light sources 2a and 2b are repeatedly turned on and off. In addition, it is possible to suppress a change in light distribution at the beginning of lighting.

  Furthermore, in the third embodiment, the fixing means 7 is provided in the center in the longitudinal direction of the light guide 3, so that the effects described below can be obtained. The effect of the third embodiment will be described with reference to FIG.

Fig.5 (a) is a side view of the linear light source device 1 which concerns on a 2nd Example, and is a figure before the light guide 3 expand | swells (shrinked state).
FIG.5 (b) is a side view when the light guide 3 of Fig.5 (a) expand | swells.
FIG.5 (c) is a side view of the linear light source device 1 which concerns on a 3rd Example, and is a figure before the light guide 3 expand | swells (shrinked state).
FIG.5 (d) is a side view when the light guide 3 of FIG.5 (c) expand | swells.

In the second embodiment, in order to allow the light guide 3 to expand, there is a gap of a distance L11 between the one end surface 33 of the light guide 3 and the one light source 2a. There is a gap of distance L12 between the other end surface 34 and the other light source 2b. When the fixing means 7 is provided at the end of the light guide 3 as in the second embodiment, the light distribution at the beginning of lighting is between the one end surface 33 of the light guide 3 and the one light source 2a. It is determined by the ratio (L11: L12) between the gap distance L11 and the gap distance L12 between the other end surface 34 of the light guide 3 and the other light source 2b.
The light guide 3 of the second embodiment is heated and expanded when its both end faces 33 and 34 are incident with light. At this time, as shown in FIG. 5B, since the fixing means 7 is provided at the end in the longitudinal direction of the light guide 3 (on the left side of the paper), the light guide 3 is used with the fixing means 7 as a fulcrum. Expands toward the right side of the page with respect to the support 5. Since the light sources 2 a and 2 b are fixed to the light source fixing body 53 of the support 5, the gap between the light guide 3 and the other light source 2 b is filled by the expansion of the light guide 3. The other end surface 34 of the light guide 3 and the other light source 2b approach each other. On the other hand, there is almost no expansion toward the one end surface 33 of the light guide 3, and the distance L21 of the gap between the one end surface 33 of the light guide 3 and the one light source 2a is almost the same as the distance L11 before expansion. It does n’t change. When the light guide 3 is in an expanded state, as shown in FIG. 5B, the distance L21 of the gap between the one end surface 33 of the light guide 3 and the one light source 2a, and the other of the light guide 3 The ratio (L21: L22) of the gap L22 between the end surface 34 and the other light source 2b (L21: L22) is different from the ratio (L11: L12) before the expansion (the contracted state). Therefore, in the second embodiment, the light distribution before the light guide 3 expands is different from the light distribution after the light guide 3 expands.

The third embodiment has a gap of a distance L31 between one end surface 33 of the light guide 3 and one light source 2a in order to allow expansion of the light guide 3, and the light guide 3 There is a gap of a distance L32 between the other end surface 34 and the other light source 2b. When the fixing means 7 is provided in the center of the light guide 3 as in the third embodiment, the distribution of light distribution at the beginning of lighting is the gap between the one end surface 33 of the light guide 3 and the one light source 2a. And the distance L32 of the gap between the other light source 2b of the other end face 34 of the light guide 3 (L31: L32).
The light guide 3 of the third embodiment is heated and expanded when its both end faces 33 and 34 are incident with light. At this time, as shown in FIG. 5 (d), the fixing means 7 is provided at the center in the longitudinal direction of the light guide 3. On the other hand, it expands in the left-right direction. Since the light sources 2 a and 2 b are fixed to the light source fixing body 53 of the support 5, the gap between one surface of the light guide 3 and the one light source 2 a is filled by expansion of the light guide 3. In addition, the gap between the other surface of the light guide 3 and the other light source 2 b is filled by the expansion of the light guide 3. Since the fixing means 7 is provided in the center in the longitudinal direction of the light guide 3, the expansion amount toward the one light source 2a and the expansion amount toward the other light source 2b are the same. For this reason, when the light guide 3 is in an expanded state, as shown in FIG. 5D, the gap L41 between the one end surface 33 of the light guide 3 and the one light source 2a, and the light guide The ratio (L41: L42) of the gap distance L42 between the other end surface 34 and the other light source 2b (3) coincides with the ratio (L31: L32) before the expansion (the contracted state). Therefore, the third embodiment can approximate the light distribution when the light guide 3 at the beginning of lighting is not expanded and the light distribution when the light guide 3 after lighting is expanded. .

  When the light guide 3 and the support 5 are fixed at one place as in the first to third embodiments, the rod-shaped light guide 3 has a longitudinal direction. It may bend without extending along the longitudinal direction. A fourth embodiment will be described as an example in which such bending of the light guide 3 is suppressed.

FIG. 6 is an explanatory diagram of the linear light source device 1 according to the fourth embodiment of the present invention.
FIG. 6A is a perspective view showing the linear light source device 1 with the spring 8 removed.
FIG. 6B is a side view showing a state in which the spring 8 is attached to the linear light source device 1 of FIG.
FIG.6 (c) is sectional drawing orthogonal to the longitudinal direction of the light guide 3 of FIG.6 (b) (CC sectional drawing of FIG.6 (b)).
6B and 6C show the light source fixing member 53 omitted in FIG. 6A.
In FIG. 6, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

6 differs from FIG. 3 in that a spring 8 is provided.
As an explanation of the fourth embodiment of FIG. 6, the explanation of the parts common to FIG. 3 will be omitted, and the parts that are different will be explained.

  Although the protruding portion 35 of the light guide 3 and the protruding portion facing portion 52 of the support 5 are fixed by the fixing means 7, the fixing means 7 is provided in the longitudinal direction of the light guide 3. In, there is only one place. For this reason, in the part where the fixing means 7 is not provided, the longitudinal direction of the light guide 3 is bent with respect to the longitudinal direction of the support 5, and the light sources 2 a and 2 b and the end faces 33 and 34 of the light guide 3. Cannot be opposed to each other, and the light from the light sources 2a and 2b cannot be incident on the inside of the light guide 3.

For this reason, as shown in FIG. 6, the bending of the light guide 3 can be prevented by sandwiching the protrusion 35 of the light guide 3 and the protrusion facing portion 52 of the support 5 by the spring 8. .
As shown in FIG. 6C, the spring 8 restricts movement in the rotational direction with respect to the longitudinal direction of the light guide 3, but does not restrict movement in the longitudinal direction of the light guide 3. . Therefore, when the light guide 3 expands, the light guide 3 can be allowed to expand while preventing the light guide 3 from bending.

  In the embodiments described above, the adhesive 6 is exemplified as the fixing means 7, but the fixing means 7 other than the adhesive 6 will be described as a fifth embodiment.

FIG. 7 is an explanatory diagram of the linear light source device 1 according to the fifth embodiment of the present invention.
FIG. 7A is a perspective view showing each member of the linear light source device 1 in an exploded state.
FIG. 7B is an enlarged view of a portion surrounded by a dotted circle in FIG.
FIG.7 (c) is sectional drawing orthogonal to the longitudinal direction of the light guide 3 in the state which assembled each member of the linear light source device 1 of Fig.7 (a) (D- of Fig.7 (a)). D sectional view).
In FIG. 7C, the light source fixing member 53 and the diffuse reflection sheet 4 omitted in FIG. 7A are illustrated.
In FIG. 7, the same components as those shown in FIG. 6 are denoted by the same reference numerals.

FIG. 7 is different from FIG. 6 in that a concave portion 351 is provided in the protruding portion 35 of the light guide 3 and a protruding portion 521 is provided in the protruding portion facing portion 52 of the support 5.
As an explanation of the fifth embodiment of FIG. 7, the explanation of the parts common to FIG. 6 will be omitted, and the parts that are different will be explained.

As shown in FIG. 7B, the protrusion 35 of the light guide 3 is provided with a recess 351 on the surface of the support 5 that faces the protrusion facing part 52. In addition, the protruding portion facing portion 52 of the support 5 is provided with a protruding portion 521 that fits into the recessed portion 351. The recess 351 and the protrusion 521 are fitted, and this fitted state functions as the fixing means 7.
The light guide 3 can regulate the movement of the light guide 3 in the longitudinal direction by fitting the recess 351 and the protrusion 521. Thereby, when the light guide 3 is expanded or contracted, a portion where the recess 351 and the protrusion 521 are fitted can be used as a fulcrum.
In addition, by providing the spring described in the fourth embodiment so as to restrict the movement of the light guide 3 in the direction of rotation with respect to the longitudinal direction, the fitting state between the recess 351 and the protrusion 521 can be changed. It can be held firmly.

  In the above-described embodiments, the light guide 3 has a substantially cylindrical shape, but may be a quadrangular prism as in the embodiment of FIG.

  Further, in the present invention, any structure may be used as long as light is emitted from the emission surface 32 of the light guide 3, and the light described in Patent Document 2 is provided on the surface opposite to the emission surface 32 of the light guide 3. A turning surface may be provided.

An experiment was conducted to confirm the effect of the present invention.
The configuration of the linear light source device 1 used in the experiment has the configuration shown in FIG.
The specifications of the linear light source device 1 are shown below.

The light emitting diodes provided in the light sources 2a and 2b are those that emit white light, and the copper substrate 21 is used as the substrate 21 on which the light emitting diodes are provided.
The light guide 3 is made of acrylic resin as a material, and the diameter of the cylindrical portion is φ6 mm, and the length in the longitudinal direction is 340 mm.
The diffusion sheet (not shown in FIG. 4) is made of PET resin, and this PET resin is provided with a diffuse reflection surface using a light stabilizer TiO ₂ on the surface in contact with the light guide. This diffusion sheet has a length of 335 mm and a thickness of 0.2 mm.
The material of the support 5 is polycarbonate.

In the experiment, a driving current within the maximum rated range is supplied to the light emitting diode, the light guide 3 absorbs light from the light sources 2a and 2b, and the light is turned on for about 30 minutes until the expansion of the light guide 3 is saturated. The light distribution was measured when the expansion of the light guide 3 was saturated (first measurement).
After the measurement, the light sources 2a and 2b were turned off for about 30 minutes until the light guide 3 was contracted to the original length of 340 mm.
After the light guide 3 contracted, the light sources 2a and 2b were turned on again for 30 minutes, and the light distribution was measured when the expansion of the light guide 3 was saturated (second measurement).

The light receiving part of the illuminance meter is arranged at a position 8 mm above the light exit surface of the light guide 3 (position equivalent to the original document surface of the actual machine), and a glass with a thickness of 3 mm is attached to the lower part of the illuminance meter. With reference to the center in the longitudinal direction, a total range of 400 mm including 200 mm toward the one end surface 33 and 200 mm toward the other end surface 34 was measured.
In this measurement range of 400 mm, a diffusion sheet is disposed on the back side of the exit surface of the light guide 3.

FIG. 9 shows the measurement result of the linear light source device 1.
FIG. 9 shows the first measurement result and the second measurement result. The vertical axis of FIG. 9 shows the relative intensity based on the intensity of light at the central position in the longitudinal direction of the light guide 3, and the horizontal axis of FIG. 9 represents the longitudinal direction of the light guide 3. Shows the length.
As shown in FIG. 9, the light distribution at the beginning of lighting (first measurement result) and the original light distribution after the light guide 3 is expanded and contracted and then turned on again (second measurement result). ) Was almost the same. The difference is clear even when the change in the light distribution of the conventional linear light source device 1 shown in FIG. 12 is seen.
This is because the light guide 3 and the support 5 are fixed by the fixing means 7 so that the fulcrum at the time of expansion and the fulcrum at the time of contraction can be matched. It is thought that the change in the light distribution can be suppressed.

  As shown in the above experimental results, the linear light source device 1 according to the present invention is provided with the fixing means 7 for fixing the light guide 3 and the support 5 at one place in the longitudinal direction of the light guide 3. Thus, even if lighting and extinguishing are repeated, the change in the light distribution at the beginning of lighting can be suppressed.

DESCRIPTION OF SYMBOLS 1 Linear light source device 2a One light source 2b The other light source 21 Board | substrate 23 Sealing body 3 Light guide body 32 Outgoing surface 33 One end surface 34 Other end surface 35 Projection part 351 Concave part 4 Diffusion sheet 5 Support body 51 Gutter-like surface 52 Projection part Opposing part 521 Protruding part 53 Light source fixing body 6 Adhesive 7 Fixing means 8 Spring

Claims (3)

A rod-shaped light guide,
Light sources provided at both ends of the light guide;
A support provided along the longitudinal direction of the light guide to support the light guide and fix the light source;
In a linear light source device comprising:
A linear light source device characterized in that a fixing means for fixing the support and the light guide is provided at one place in the longitudinal direction of the light guide.
Providing the light guide with a protruding portion that protrudes in a direction perpendicular to its longitudinal direction,
The support is provided with a protruding portion facing portion that faces the protruding portion,
The linear light source device according to claim 1, wherein the fixing unit fixes the protruding portion of the support and the protruding portion facing portion of the light guide.
The linear light source device according to claim 1, wherein the position where the fixing portion is provided is a center in the longitudinal direction of the light guide.

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