JP2001202815A - Linear light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve brightness unevenness of an illuminating light in a linear light source unit using a light guiding member. SOLUTION: It comprises a light guiding member 2 in the shape of a long stick emitting an illuminating light from a first side 2a and a luminous member 3 emitting light into the light guiding member 2. At a second side 2b opposing to the first side 2a of the light guiding member 2 is formed a linear light source having a plurality of grooves 12 reflecting an incident light from the luminous member 3 so that the length direction of the above grooves 12 is slantingly crossed with an incident light from the luminous member 3. This gives an effect as if the grooves are continuously arranged, significantly improving the division of the illumination light with strength and weakness like a prior art and emits a uniform illuminating light having very small unevenness of brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear light source unit used as a light source for a backlight of a display device such as a liquid crystal panel or an illumination light source of an image reading device used for a copier, an image scanner, a bar code reader, or the like. About.

[0002]

2. Description of the Related Art In recent years, a light emitting diode (hereinafter, referred to as an LED) has been widely used as a light emitting member of a linear light source unit used as a light source of a backlight of a display device or an illumination light source of an image reading device. . It is considered that an LED is most suitable for miniaturization of such a device, which leads to cost reduction.

In a conventional linear light source unit having a light emitting member such as an LED, the number of light emitting members is reduced.
For the purpose of obtaining a uniform illumination intensity, there has been known a configuration in which light emitted from a light emitting member is made incident on the light guide member and light is guided in a desired direction using a light guide member.

FIGS. 6A and 6B are views showing the structure of such a conventional linear light source unit, wherein FIG. 6A is a perspective view, FIG.
(C) is a front view, and (d) is a side view as seen from a light emitting member 133 described later. 6, a linear light source unit 110 is a long light guide member 120 made of a transparent resin or the like.
It has a light emitting member 133 composed of an LED and a reflecting member 124. Here, in FIG. 6A, illustration of the reflection member 124 is omitted for convenience.

The light guide member 120 has a first side surface 120a functioning as a light exit surface, a second side surface 120b facing the first side surface, and an end surface 120c of the light guide member 120 facing the light emitting member 133. From the first side surface 12b to the other end surface 120d.
A plurality of concave grooves 122 having an arc-shaped cross section extending in a direction parallel to the thickness direction of the light guide member 120 (or the end surface 120c) are formed while having an inclined surface 120b1 whose distance from the light guide member 120a gradually decreases. It has an uneven surface. The first side surface 120a and the second
Has a mirror-finished side surface 120b. Light emitting member 1
Reference numeral 33 denotes an LED, which is held on an LED board 131 rising from a motherboard (not shown), and is electrically connected to a light emitting member drive circuit (not shown). When a predetermined drive current flows from the light emitting member driving circuit to the light emitting member 133, the light emitting member 133 emits light.

[0006]

In the linear light source unit 110, light emitted by the light emitting member 133 enters the light guide member 120 from the end face 120c.
As shown in (b), a part of the light enters the concave groove 122 of the second side surface 120b and is totally reflected, and the first side surface 12b
The light exits from 0a. On the other hand, most of the light that enters the light guide member 120 and directly enters the first side surface 120a is reflected into the light guide member 120 by total internal reflection. In this manner, the light that has entered the light guide member 120 exhibits the strongest reflection near the top of the concave groove 122 and exits outside. For this reason, the intensity of the corresponding outgoing light is clearly separated between the portion having the concave groove 122 and the portion not having the concave groove 122.

That is, as shown in FIG.
The emission light of 0 periodically changes its luminance in the longitudinal direction, and causes stripe-like luminance unevenness. In FIG. 7, the horizontal axis represents the end surface 12.
First side surface 120 which is an emission surface from 0c to 120d
a indicates the position in the longitudinal direction, and the vertical axis indicates the luminance of the illumination light emitted to the outside from the side surface 120a. The reflecting member 124 shown in FIG. 6 is made of a metal plate or the like, and is disposed close to and opposite to a side surface other than the first side surface 120a.
The light transmitted through the side surfaces other than the side surface 120a and emitted to the outside is returned to the inside of the light guide member 120 by reflection.

The illumination light emitted from the linear light source 110 has the above-mentioned luminance unevenness. For example, when the linear light source is used directly as an illuminating means such as a scanner, the reading accuracy is reduced. Of course, this is not preferable, but in addition, the planar light source formed by combining the linear light source and the light guide plate has the following problems. FIG. 8 is a perspective view showing a planar light source 140 unit configured by directly connecting the conventional linear light source unit 110 and the planar light guide plate 130 as shown in FIG. Here, one main surface 130a of the planar light guide plate 130 functions as a light exit surface and is mirror-finished. The other main surface 130b opposite to the one main surface 130a is a diffusion surface or a reflection surface, and is subjected to roughening such as embossing.

A first side surface 120a, which is a light emitting surface of the linear light source unit 120, is coupled to one side surface of the planar light guide plate 130, and light emitted from the first side surface 120a is Of the planar light guide plate 130 and one main surface 130a that is a light exit surface and the other main surface 130 that is a diffusion surface.
b, the reflection light travels over the entire surface while being repeatedly reflected, and at the same time, the planar illumination light 1
45 is emitted. In this case, since the incident light itself from the first side surface 120a of the linear light source unit 120 to the planar light guide plate 130 has stripe-like luminance unevenness, the influence also affects the planar light guide plate 130. In addition, planar illumination light 145 emitted from one main surface 130a of planar light guide plate 130
Also causes uneven brightness. Such uneven brightness is caused by the planar light guide plate 1.
This is particularly remarkable in the vicinity of the connection portion with the 30 linear light source units 120. When luminance unevenness occurs also in the illumination light from the planar light guide plate, unintended luminance irregularity occurs on a display member such as a liquid crystal panel illuminated by the planar light source 140, and the display quality deteriorates.

Therefore, conventionally, it was necessary to take the following countermeasures. FIGS. 9A and 9B are diagrams showing a configuration of a planar light source unit according to a known improvement in which measures are taken for the planar light source unit shown in FIG. 8, wherein FIG. 9A is a perspective view, and FIG.
It is the side view seen from the 0 side. As shown in FIG. 9, in the planar light source unit 140 of this example, a light diffusing unit 135 such as a diffusion sheet is provided between the light guide member 120 and the planar light guide plate 130 of the linear light source unit, and this portion is The light to be transmitted is diffused, and the light that has been made uniform in advance is transmitted through the planar light guide plate 1.
By guiding the illumination light 30 to the surface 30, the unevenness in luminance of the planar illumination light 145 emitted from the one main surface 130a of the planar light guide plate 130 is reduced. However, such a planar light source 140
The manufacturing cost is increased by providing the diffusion means 135 such as a diffusion sheet. Further, since the diffusing means 135 diffuses the light in various directions, some of the diffused light does not enter the planar light guide plate 130, and as a result, the luminance level of the illumination light 145 emitted from the planar light source 140. Lower.

The present invention relates to a conventional long light guide member and an LED.
An object of the present invention is to improve the above-mentioned uneven brightness in the emitted light of a linear light source provided with a light emitting member such as described above. The present invention further eliminates the need for intervening light diffusion means such as the above-mentioned diffusion sheet in a planar light source obtained by combining such a linear light source and a planar light guide plate, and reduces luminance unevenness without lowering the luminance of illumination light. It also solves the problem of preventing manufacturing costs from increasing.

[0012]

As a first means for solving the above-mentioned problems, the present invention provides a long light guide member for emitting illumination light from a first side face, and the light guide member. A linear light source comprising: a light emitting member that emits light to the light guide member; and a plurality of grooves that reflect incident light from the light emitting member on a second side surface of the light guide member that faces the first side surface. A longitudinal direction of the plurality of grooves is oblique to a direction of incident light from the light emitting member.

As a second means for solving the above-mentioned problems, the present invention provides a first side surface for emitting illumination light, a second side surface facing the first side surface, a first side surface, and a second side surface. 2
A long light guide member having a third side surface and a fourth side surface extending substantially in the horizontal direction and extending substantially in the horizontal direction, and partitioning the longitudinal direction of the light guide member. A light-emitting member for making light incident on the light-guiding member from an end face;
In a linear light source provided with a plurality of grooves for reflecting incident light from the light emitting member on a side surface of the linear light source, the longitudinal direction of the plurality of grooves is 30 degrees to 60 degrees with respect to the third side surface or the fourth side surface.
It is characterized by being inclined at an angle.

As a third means for solving the above-mentioned problems, the present invention provides a first side surface for emitting illumination light, a second side surface facing the first side surface, a first side surface and a first side surface. 2
A long light guide member having a third side surface and a fourth side surface extending substantially in the horizontal direction and extending substantially in the horizontal direction, and partitioning the longitudinal direction of the light guide member. A light-emitting member for making light incident on the light-guiding member from an end face;
In a linear light source provided with a plurality of grooves for reflecting incident light from the light-emitting member on a side surface of the linear light source, a longitudinal direction of the plurality of grooves is inclined by approximately 45 degrees with respect to the third side surface or the fourth side surface. It is characterized by having.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, according to one of the first to third means, a cross section of the plurality of grooves provided on the second side surface is provided. It is characterized by being substantially arc-shaped or V-shaped.

According to a fifth aspect of the present invention, there is provided a flat light diffusing device for emitting illumination light of a planar light source according to any one of the first to fourth means. A linear light source is directly coupled to or integrated with the side surface of the member, and reflected light from the second side surface is incident on the light diffusion member.

According to a sixth aspect of the present invention, there is provided the present invention, in any one of the first to fifth means, wherein the first side face, the second side face and a plurality of grooves are provided. Is characterized in that its surface is subjected to a mirror finish or a diffusion treatment such as embossing.

According to a seventh aspect of the present invention, to solve the above-mentioned problem, in any one of the first to sixth means, the distance between the first side surface and the second side surface is the same. It is characterized in that it becomes smaller as the distance from the light emitting member increases.

According to an eighth aspect of the present invention, in order to solve the above-mentioned problems, in any one of the first to seventh means, the light emitting member is an LED.

The present invention as a ninth means for solving the above-mentioned problems, according to the eighth means, comprises the following:
D is a white LED.

According to a tenth aspect of the present invention, to solve the above-mentioned problem, the present invention provides the eighth aspect,
ED is an L of R, G, B arranged in a row in a direction substantially parallel or perpendicular to the first side surface or the second side surface.
ED.

According to an eleventh aspect of the present invention, in order to solve the above-mentioned problems, there is provided the present invention in any one of the first to tenth aspects, wherein the second side face or the second side face,
A reflection member such as a reflection tape or a reflection plate is provided in close contact with or close to the third side surface and the fourth side surface.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This embodiment relates to a linear light source unit. 1A and 1B are diagrams showing a configuration of a linear light source unit according to the present embodiment, where FIG. 1A is a perspective view, FIG. 1B is a top view, FIG. 1C is a front view, and FIG. It is the side view seen from 3 sides. In FIG. 1A, for the sake of convenience, the illustration of a reflection member 4 described later is omitted. In FIG. 1, reference numeral 1 denotes a linear light source unit, which has a long light guide member 2 made of a transparent resin or the like, a light emitting member 3 made of an LED, and a reflection member 4.

The light guide member 2 has a first functioning as a light exit surface.
Side surface 2a, a second side surface 2b opposed to the first side surface, a third side surface 2e substantially orthogonal to the first side surface and the second side surface, and extending in the horizontal direction to partition these vertical widths; It has a fourth side face 2f, one end face 2c facing the light emitting member 3 and partitioning the light guide member 2 in the longitudinal direction, and the other end face 2d facing the one end face. The second side surface b has an arc-shaped cross section on its surface,
A plurality of grooves 12 extending in a direction inclined by 30 to 60 degrees with respect to the side surface 2e or the fourth side surface 2f.
A flat portion 2b1 other than the plurality of concave grooves 12 on the second side surface 2b
Is an inclined surface in which the distance from the first side surface 2a gradually decreases from the end surface 2c of the light guide member 2 facing the light emitting member 3 to the other end surface 2d. The first side surface 2a, the second side surface 2b, and the plurality of concave grooves 12
Has a mirror-finished surface.

The light emitting member 3 is formed of an LED, and is held at a position close to and opposite to the end surface 2c of the light guide member 2 by an LED substrate 31 rising from a mother board (not shown), and is electrically connected to a light emitting member drive circuit (not shown). . When a predetermined drive current flows from the light emitting member drive circuit to the light emitting member 3, the light emitting member 3 emits light. As the light emitting member 3 made of an LED, for example, a white LED can be used.

When the light emitting member 3 emits light, the light enters the light guide member 2 from the end face 2c. Most of the light that has entered the light guide member 2 is reflected directly or after reflection by the first side surface 2a, or after reflection between the plane portion 2b1 of the second side surface and the first side surface 2a. 2 reaches the surface of the plurality of grooves 12 provided on the side surface 2b, where the first side surface 2
The light is reflected toward the first side surface 2a and exits from the first side surface 2a as illumination light. At this time, in the plurality of concave grooves 12, since the strongest reflection is shown near the top of the groove, the illumination light also has a part with and without the groove, as in the conventional example shown in FIG.
Originally, it has the property that the intensity of light is divided.

However, in the present embodiment shown in FIG. 1, since a plurality of concave grooves 12 are provided diagonally, it has an effect as if the grooves were continuously provided. Divergence of the intensity of the illumination light depending on such places is greatly improved, and uniform illumination light with less luminance unevenness can be emitted. The oblique angle of the groove 12 is 30 degrees with respect to the third side surface 2e or the fourth side surface 2f.
Even if it is less than 60 degrees or more than 60 degrees, the reflection efficiency for uniformity of illumination drops, and the case of 45 degrees increases such reflection efficiency and is most desirable in eliminating luminance unevenness of illumination light,
It is recognized by the inventor's experience. FIG. 2 is a diagram showing the luminance distribution of the illumination light emitted from the first side surface 2a along the longitudinal direction of the light guide member 120 when the oblique angle of the concave groove 12 is approximately 45 degrees. In FIG. 2, the horizontal axis is the end face 2c.
The vertical axis indicates the luminance of the illumination light emitted from the side surface 2a to the outside. As shown in FIG. 2, in this case, the luminance is almost constant regardless of the location.

As shown in FIG. 1, the reflecting member 4 is
Other than the first side 2a, that is, the second side 2b,
The cross-section, which is disposed close to and opposed to the third side surface 2e and the fourth side surface 2f, is made of a coating member such as a U-shaped metal,
The second side surface 2b, the third side surface 2e, and the fourth side surface 2f
It reflects light that exits from the outside and returns it to the light guide member 2. Thereby, the light that is transmitted to the outside unnecessarily is reduced, the conversion efficiency of the optical path is increased, and finally, the light amount of the light emitted from the first side surface 2a is further increased, thereby contributing to the improvement of the luminance of the illumination light. . In this case, in particular, the groove 1
When the incident angle of the light incident from the inside of the light guide member 2 with respect to the surface 2 is less than the critical angle θc, the light is transmitted to the outside without being totally reflected. The effect of reuse and reuse is great. Even if the reflection member is provided so as to face only the second side surface 2b, a considerable effect can be obtained. The type of the reflection member may be a reflection tape or the like.

In this manner, the linear light source unit 1 according to the present embodiment can emit uniform illumination light with less luminance unevenness from the first side surface 2a of the light guide member, which is the light output surface. Therefore, when the linear light source unit 1 is directly used as the illumination means, it is possible to illuminate the object with uniform brightness in the linear illumination area. For example, in a scanner, such a linear light source unit is used as illumination light for a document, thereby enabling illumination of a read line with uniform brightness, and contributing to improvement in read fidelity and reproducibility as compared with the related art. .

As described above, in the present embodiment,
Although the surfaces of the first side surface 2a, the second side surface 2b, and the plurality of concave grooves 12 of the light guide member 2 are mirror-finished, the present invention is not limited to this, and these surfaces may be subjected to diffusion treatment such as graining. Even if the surface is provided with, the same effect as described above can be obtained by the reflection action of the surface. Further, the cross-sectional shape of the plurality of concave grooves 12 is not limited to the arc shape as shown in FIG. Have substantially the same effect.

Next, according to the present invention, by combining such a linear light source unit and a planar light guide plate, an excellent planar state used as a backlight or other illuminating means of a planar display device such as a liquid crystal panel. A light source unit can be configured. FIGS. 3A and 3B show a configuration of such a planar light source using a linear light source as another embodiment of the present invention, wherein FIG. 3A is a perspective view and FIG. 3B is a side view. FIG.
In the figures, 10 is a planar light source unit, and 7 is a planar light guide plate. The planar light source unit 10 is a combination of the planar light guide plate 7 and the linear light source unit 1 shown in FIG.
The symbols of the components related to the linear light source unit 1 are the same as those in FIG. Here, the planar shape of the planar light guide plate 7 is quadrangular, and one main surface 7a functions as a light exit surface and is mirror-finished. The other main surface 7b opposite to the one main surface 7a is a diffusion surface or a reflection surface, and dots are formed by rough surface processing such as embossing.

The first side surface 2a, which is the light emitting surface of the linear light source unit 1, is coupled to one side surface of the planar light guide plate 7, and the light emitted from the first side surface 2a is Of the planar light guide plate 7, the light is repeatedly reflected between the one main surface 7a, which is the light exit surface, and the other main surface 7b, which is the diffusion surface, and travels from one main surface 7a to the other. The illumination light 11 is emitted. In this case, since the incident light itself from the first side surface 1a of the linear light source unit 1 to the planar light guide plate 7 has a uniform luminance with almost no luminance unevenness, the influence is not affected. The illumination light 11 having uniform brightness with almost no luminance unevenness is emitted from one main surface 7a of the planar light guide plate 7.

As described above, according to the planar light source unit 10 according to the present embodiment, like the conventional planar light source unit (140) shown in FIG. 9, the distance between the linear light source unit and the planar light guide plate is increased. The illumination light having a uniform brightness with almost no luminance unevenness can be obtained without interposing a diffusing member (135) such as a diffusing sheet, so that the manufacturing cost can be reduced as compared with the related art by the interposition of the diffusing member. . In addition, the luminance of the illumination light caused by the diffusion means does not decrease, and brighter illumination than before can be achieved.

In the case of the planar light source unit 10 shown in FIG. 3, the light guide member 2 of the linear light source unit 1 and the planar light guide plate 7 are separately formed of a transparent resin or the like, and then bonded by an adhesive or the like. However, the present invention is not limited to this, and they can be integrally formed by molding or the like.

Incidentally, in the linear light source 1 shown in FIG. 1 or the planar light source unit 10 shown in FIG. 3, the light emitting member 3 is composed of one LED, but the present invention is not limited to this. Are arranged in a line to form R, G, B LEDs. FIG. 4 is a perspective view showing a configuration of a linear light source unit (1) including R, G, and B LEDs arranged in a row as the light emitting member 3. As shown in FIG.
R, G, and B LEDs 3r, 3g, which constitute the light emitting member 3,
3b is supported by the LED substrate 31 at a position facing the end surface 2c of the linear light source unit, and is arranged in a line in a direction perpendicular to the first side surface 2a.

From the light emitting member driving circuit (not shown), R, G,
When a predetermined drive current is individually supplied to the B LEDs 3r, 3g, 3b, the LEDs 3r, 3g, 3b individually emit R, G, B colors, and the light is transmitted from the end face 2c to the light guide member. Enter 2. When the LEDs 3r, 3g, and 3b have such an arrangement, the components in the vertical direction of the incident angle with respect to the second side surface 2b are substantially the same for each color, and the light of each color entering the light guide member 2 has already been described. According to the same principle as described above, the light path of each color is changed under substantially the same conditions,
Illumination light without luminance unevenness is emitted from the first side surface 2a. The illumination light of each color of R, G, and B can illuminate an object by emitting a single color or a plurality of colors simultaneously, as needed. Thereby, illumination of various color tones without luminance unevenness becomes possible.

Next, FIGS. 5A and 5B are views showing a modified example of the linear light source unit shown in FIG. 4, in which FIG. 5A is a front view, and FIG. 5B is a side view as seen from the light emitting member 3 side. As shown in FIG. 5, the R, G, and B LEDs 3r, 3
g and 3b are supported by the LED substrate 31 at positions facing the end surface 2c of the light guide member 2, and are arranged in a line in a direction parallel to the first side surface 2a. As above,
The LEDs 3r, 3g, and 3b respectively emit light of R, G, and B colors, and the light enters the light guide member 2 from the end face 2c. When the LEDs 3r, 3g, and 3b have such an arrangement, the components in the horizontal direction of the incident angle with respect to the second side surface 2b are substantially the same for each color as a whole, and the light of each color entering the light guide member 2 is The light path of each color is changed under substantially the same conditions, and the light is emitted from the first side surface 2a of the light guide member 2 as illumination light without luminance unevenness. Thus, the linear light source 1 according to the present embodiment has the same effect as the linear light source (1) shown in FIG.

[0038]

As described above, according to the present invention, in a linear light source provided with a long light guide member and a light emitting member such as an LED, the brightness unevenness of the emitted light can be improved and the uniformity can be improved. Brightness illumination can be enabled. The present invention further provides a planar light source obtained by combining such a linear light source and a planar light guide plate, in which the need for a diffusion sheet or the like is eliminated, the luminance unevenness is improved without lowering the luminance of the illumination light, and manufacturing is performed. An increase in cost can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a linear light source unit according to an embodiment of the present invention.

FIG. 2 is a diagram showing a distribution of luminance of illumination light emitted from the linear light source unit shown in FIG.

FIG. 3 is a diagram showing a configuration of a planar light source unit using the linear light source unit shown in FIG.

FIG. 4 shows R, G, and R according to another embodiment of the present invention.
It is a figure showing composition of a linear light source unit using LED of B.

5 is a diagram showing a configuration of a modified example of the linear light source unit shown in FIG.

FIG. 6 is a diagram showing a configuration of a conventional linear light source unit.

FIG. 7 is a diagram showing a luminance distribution of illumination light emitted from the linear light source unit shown in FIG. 6;

8 is a diagram showing a configuration of a planar light source unit using the linear light source unit shown in FIG.

9 is a diagram showing a configuration of a known improved example of the planar light source unit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear light source unit 2 Light guide member 2a 1st side surface 2b 2nd side surface 3 Light emitting member 3r R LED 3g G LED 3b B LED 4 Reflection member 7 Planar light guide plate 10 Planar light source unit 10a 1st Main surface 10b Second main surface 11 Illumination light 12 Groove 31 LED board

[Procedure amendment]

[Submission date] January 24, 2000 (2000.1.2
4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C051 AA01 DB21 DB29 DB31 DC05 DC07 EA01 FA01 5C072 AA01 BA02 BA05 BA15 CA05 CA07 CA09 DA04 DA16 DA21 DA30 QA11 XA01

Claims (11)

[Claims] An elongate light guide member that emits illumination light from a first side surface; and a light emitting member that emits light to the light guide member. The light guide member faces the first side surface of the light guide member. In a linear light source having a plurality of grooves on the second side surface for reflecting incident light from the light emitting member, the longitudinal direction of the plurality of grooves is oblique to the direction of the incident light from the light emitting member. A linear light source. 2. A first side surface from which illumination light is emitted, a second side surface opposite to the first side surface, substantially perpendicular to the first side surface and the second side surface, extending in the horizontal direction, and vertically A long light guide member having a third side surface and a fourth side surface that partition the width in the direction, and a light emitting member that makes light incident on the light guide member from an end surface that partitions the longitudinal direction of the light guide member. In a linear light source provided with a plurality of grooves on the second side surface for reflecting incident light from the light emitting member, a longitudinal direction of the plurality of grooves is
A linear light source characterized by being inclined by 30 to 60 degrees with respect to the third side surface or the fourth side surface. 3. A first side surface for emitting illumination light, a second side surface opposite to the first side surface, substantially perpendicular to the first side surface and the second side surface, extending in the horizontal direction, and extending vertically. A long light guide member having a third side surface and a fourth side surface that partition the width in the direction, and a light emitting member that makes light incident on the light guide member from an end surface that partitions the longitudinal direction of the light guide member. In a linear light source provided with a plurality of grooves on the second side surface for reflecting incident light from the light emitting member, a longitudinal direction of the plurality of grooves is
A linear light source characterized by being inclined at approximately 45 degrees with respect to the third side surface or the fourth side surface. 4. The linear light source according to claim 1, wherein a cross section of the plurality of grooves provided on the second side surface is substantially arc-shaped or V-shaped. 5. A linear light source is directly coupled to or integrated with a side surface of a flat light diffusion member that emits illumination light of a planar light source, and reflected light from the second side surface is incident on the light diffusion member. The linear light source according to any one of claims 1 to 4, wherein: 6. The method according to claim 1, wherein the first side surface, the second side surface, and the surfaces of the plurality of grooves have been subjected to a mirror finish or a diffusion process such as embossing. The linear light source according to 1. 7. The linear light source according to claim 1, wherein a distance between the first side surface and the second side surface decreases as the distance from the light emitting member increases. 8. The linear light source according to claim 1, wherein the light emitting member is an LED. 9. The linear light source according to claim 8, wherein the LED is a white LED. 10. The LED may be connected to the first side or the second side.
9. The linear light source according to claim 8, comprising R, G, and B LEDs arranged in a line in a direction substantially parallel or perpendicular to a side surface of the LED. 11. The second side or the second side, the third side
The linear light source according to any one of claims 1 to 10, wherein a reflection member such as a reflection tape or a reflection plate is disposed in close contact with or close to the side surface and the fourth side surface.