JPH11238408A - Linear beam projecting device and plane lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear beam projecting device which can suppress the power consumption using a single unit of spot light source and can emit high- brightness light linearly in a uniform distribution. SOLUTION: A linear beam projecting device 17 is composed of a single unit of spot light source 12, a first photo-guide member 14 in rod shape which has an incident end face 13 for receiving the light from the source 12, a light emitting surface 15 to emit light transmitted from the incident end face 13, and a backside 24 positioned on the opposite side to the light emitting surface 15 and in which the incident end face 13 is positioned at one-side ends of the light emitting surface 15 and the backside 24, and a first photo-reflective sheet 16 which covers those areas of the first photo-guide member 14 except the incident end face 13 and light emitting surface 15, wherein a plurality of protrusions 28 for projecting beams of light in converged condition to the first photo-reflective sheet 16 are formed on the backside 24 of the photo-guide member 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear light projecting device for emitting light in a linear manner and a flat lighting device incorporating the linear light projecting device, and more particularly to a flat lighting device suitable for use in illuminating a liquid crystal display surface. Things.

[0002]

2. Description of the Related Art A flat illuminating device used as a so-called backlight light source of a liquid crystal display guides light from a light source into a transparent light guide plate from a side end face thereof into the light guide plate, and reflects light from the light guide plate. This light is uniformly emitted from the entire surface of the light guide plate. In consideration of the characteristics of the liquid crystal display in which the flat illuminator is used, functions required for the flat illuminator include a thin plate shape as a whole and a function to minimize power consumption of the light source. In particular, it is particularly important to emit uniform light throughout.

Conventionally, a CFL (cold-cathode tube) has been most commonly used as a light source used in such a flat lighting device. However, in a liquid crystal display incorporated in a portable electronic device, a light emitting diode array or the like is also used. in use.

When a CFL is used as a light source, the CFL
The size of the light source is reduced by reducing the diameter or thickness of the light source. In addition, there is also known one incorporating an inverter for increasing the driving frequency of the CFL in order to improve the luminance and suppress power consumption.

[0005]

If the diameter of the CFL is reduced or the thickness of the CFL is reduced in order to make the liquid crystal display thinner, it is difficult to form a long CFL in a straight line without distortion. In addition, since it has weak mechanical strength, mounting it on a liquid crystal display incorporated in a portable electronic device poses a serious problem in terms of reliability.

Incorporating an inverter to improve brightness and suppress power consumption not only generates high frequency noise, but also increases the manufacturing cost due to the increase in the number of components, and reduces the size of the electronic device itself. There is a risk of inhibition.

Particularly, in a liquid crystal display incorporated in a portable electronic device, suppression of power consumption is important for determining the life of a battery, and a light source with low power consumption and high brightness has been desired. .

[0008]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a linear light source capable of suppressing power consumption by using a single point light source and emitting high-brightness light linearly with a uniform distribution. An object of the present invention is to provide a light projection device.

A second object of the present invention is to provide a compact planar lighting device using the linear light projecting device.

[0010]

According to a first aspect of the present invention, there is provided a single point light source for projecting light, an incident end face for introducing light from the point light source, and an incident end face for inputting light from the incident end face. A light emitting member having a light emitting surface portion for emitting the emitted light, and a back surface portion located on the opposite side of the light emitting surface portion, wherein the incident end surface portion is a rod-shaped light guide member located on one end side of the light emitting surface portion and the rear surface portion A light-reflecting sheet that covers portions other than the incident end surface and the output surface of the light-guiding member, and the rear surface of the light-guiding member condenses light toward the light-reflecting sheet. A plurality of projections for emitting light are formed, and these projections have a triangular outline shape projected perpendicularly to the back surface of the light guide member, and one side thereof is the incident end face of the light guide member. Is set almost parallel to the A linear light projection device, which is located closer to the incident end face of the light guide member than the apex of the linear light projection member.

According to the first aspect of the present invention, a part of the light from the point light source, which enters the light guide member from the incident end face, is totally reflected by the back surface of the light guide member, and the light guide member has no loss. Out of the light guide member from the light exit surface of the light guide member. A part of the light incident on the convex portion is emitted from the light guide member toward the light reflecting sheet in a condensed state, but is reflected in a scattering state while maintaining the light condensing property by the light reflecting sheet. The light enters the light guide member again from the side, and finally exits all from the emission surface of the light guide member.

In a second aspect of the present invention, there is provided a single point light source for projecting light, an incident end face for introducing light from the point light source, and emitting light incident from the incident end face. A rod-shaped light guide member having an emission surface portion, and a back surface portion opposite to the emission surface portion, wherein the incident end surface portion is located at one end of the emission surface portion and the back surface portion; A light reflecting sheet covering a part other than the incident end face part and the emission face part of the member, and the emission face part has a light collecting property and a direction control property, and the light reflected on the back face part is provided. A plurality of projections for emitting light from the emission surface are formed, and these projections have a triangular outline shape projected perpendicularly to the emission surface, and one side thereof is set substantially parallel to the incident end surface. And the one side is Are also located on the incident end face side.

According to the second aspect of the present invention, a part of the light from the point light source, which enters the light guide member from the incident end face, is totally reflected on the back surface of the light guide member, and the light guide member is lost without loss. Out of the light guide member from the light exit surface of the light guide member. In addition, a part of the light incident on the convex portion is emitted as it is to the outside of the light guide member in a condensed state, and finally exits entirely from the emission surface of the light guide member.

On the other hand, a third embodiment according to the present invention is a single point light source for projecting light, an incident end face for introducing light from the point light source, and emitting light incident from the incident end face. A first surface having a light-emitting surface portion, and a back surface portion located on the opposite side of the light-emitting surface portion, wherein the incident end surface portion has a rod-like shape located on one end side of the light-emitting surface portion and the rear surface portion.
A light guide member, a first light reflection sheet covering portions other than the incident end face portion and the emission face portion of the first light guide member, and a light guide member connected to the emission face portion of the first light guide member. A light incident surface for introducing light, an light emitting surface for emitting light incident from the light incident surface, and a back surface located opposite to the light emitting surface, wherein the light incident surface is the light emitting surface. And a plate-shaped second light guide member located on one end side of the back surface portion, and a second light reflection sheet that covers portions of the second light guide member other than the incident end surface portion and the emission surface portion. A flat lighting device characterized by comprising:

According to the third aspect of the present invention, the light projected from the light source enters the first light guide member from the incident end face of the first light guide member, and a part of the light enters the first light guide member. The light exits from the exit surface of the light guide member. Also, light that leaks from the portion other than the emission surface of the first light guide member to the outside of the first light guide member re-enters the first light guide member by the first light reflection sheet, and is finally formed. All light is emitted from the emission surface of the first light guide member. The light emitted from the emission surface of the first light guide member enters the second light guide member from the incident end surface of the second light guide member, and a part of the light is emitted from the second light guide member. The light exits from the exit surface. Also, light that leaks from the portion other than the emission surface of the second light guide member to the outside of the second light guide member is again incident on the second light guide member by the second light reflection sheet, and is finally formed. Then, all light is emitted from the emission surface of the second light guide member.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the linear light projection device according to the first embodiment of the present invention, a light deflecting means for deflecting light emitted from an emission surface in a predetermined direction may be formed on the emission surface. Good. In this case, the light deflecting means may be a prism having a triangular prism shape extending in a direction orthogonal to the incident end face and arranged along the width direction of the light guide member, or a spherical lens array having a predetermined radius of curvature. It may be.

Further, a contour shape perpendicularly projected to the back surface forms a triangle, one side of which is set substantially parallel to the incident end face, and a vertex with respect to the one side is located closer to the incident end face than the one side. A plurality of second protrusions may be formed on the back surface. It is preferable that the triangles of the convex portion and the second convex portion are isosceles triangles, and are inclined with respect to the back surface and include a cone surface including one side and a pair of cone surfaces substantially perpendicular to the back surface. Or a triangular pyramid, each having a triangular prism shape.
Further, the convex portion and the second convex portion may be integrally formed by sharing one side, and in this case, the convex portion and the second convex portion may be formed in a quadrangular prism shape as a whole.

Further, the angle formed by the two oblique sides including the vertices of the triangle is n, where n is the refractive index of the material forming the convex portion, and β is the angle between the light beam incident on the convex portion and the plane portion. ta
n ^-1 [cosβ · tan {π-2sin ^-1 (1 / n)}] or more is desirable. Further, the ratio of the convex portion per unit area of the exit surface portion may be set to be larger as the distance from the incident end surface portion increases, or the ratio of the first and second convex portions per unit area of the exit surface portion may be set to the length of the incident end surface portion. It is desirable that the width is set to be relatively large at both ends in the width direction of the emission surface along the direction. It is effective that these first and second convex portions are randomly arranged on the light emitting surface portion, and their size is preferably 150 μm or less. The lengths of the two oblique sides of the convex portion and the lengths of the two oblique sides of the second convex portion may be different from each other.

In the linear light projection device according to the second aspect of the present invention, a triangular prism-shaped prism surface is arranged on the back surface of the light guide member in a direction parallel to the incident end surface and extends in a direction perpendicular to the incident end surface. May be formed.

Also, the outline shape projected perpendicularly to the exit surface portion forms a triangle, one side of which is set substantially parallel to the incident end surface portion, and the vertex for the one side is located closer to the incident end surface portion than the one side. A plurality of second convex portions may be formed on the emission surface portion. In this case, the triangles of the first and second convex portions are preferably isosceles triangles, and are inclined with respect to the emission surface portion and have a conical surface including one side;
It may be a triangular pyramid consisting of a pair of pyramids that are substantially perpendicular to the exit surface, or may be triangular prism-shaped. These first and second projections may be integrally formed with one side shared. In this case, the first and second projections may be in the shape of a quadrangular prism as a whole. The angle formed by the two hypotenuses including the vertices of the triangle is n, the refractive index of the material forming the projection, and β is the angle between the light ray incident on the projection and the plane portion,
It is desirable that the value be equal to or larger than tan ⁻¹ [cosβ · tan {π−2 sin ⁻¹ (1 / n)}].

Further, the ratio of the first convex portion to the surface area per unit area is set to be larger as the distance from the incident end face is increased, or the ratio of the first and second convex portions to the surface area per unit area is increased. Is desirably set relatively large at both end portions in the width direction of the surface portion along the longitudinal direction of the incident end face portion, and the first and second convex portions are randomly arranged on the surface portion. Is valid. The lengths of the two oblique sides of the first convex portion and the lengths of the two oblique sides of the second convex portion may be different from each other.

In the linear light projecting devices according to the first and second embodiments of the present invention, the convex portion is set such that the ratio of the rear surface portion to the unit area increases as the distance from the incident end surface of the light guide member increases. May be used. In this case, the amount of light emitted from the emission surface is made uniform along the longitudinal direction of the emission surface.

The point light source may be a light emitting diode or a semiconductor laser.

An optical surface for adjusting the incident state of light from a point light source may be formed on the incident end face of the light guide member. In this case, the optical surface may be a concave lens surface that diverges light, a convex lens surface that converges light, or a plane that is perpendicular or inclined to the longitudinal direction of the light guide member. The optical axis may be parallel or inclined with respect to the longitudinal direction of the light guide member. When the optical surface is a convex lens surface,
Light incident on the light guide member from the incident end surface is deflected symmetrically about the optical axis in a convergent state, and finally exits from the exit surface. When the optical surface is a concave lens surface, light incident on the light guide member from the incident end surface is deflected symmetrically about the optical axis in a divergent state, and finally exits from the exit surface. When the optical surface is a plane perpendicular or inclined with respect to the longitudinal direction of the light guide member, light incident on the light guide member from the incident end face portion is equally deflected in a predetermined direction, and finally exits from the output surface portion. .

Further, the back surface of the light guide member may be a plane parallel to the light exit surface of the light guide member. Or,
It may be a flat surface or a curved surface so that the distance from the light-emitting member to the light-exiting surface decreases as the distance from the light-entering end surface of the light-guiding member increases. When the back surface is formed as an inclined plane, the light transmitted through the light guide member is emitted from the emission surface while being more strongly deflected toward the emission surface. In the case where the back surface is formed as a curved surface, light is more strongly deflected toward the emission surface side as the back surface is farther from the incident end surface, and emitted from the emission surface.

On the other hand, in the flat lighting device according to the third aspect of the present invention, the light incident from the incident end face of the first light guide member is provided on the back surface of the first light guide member. A plurality of projections for total reflection may be formed on the exit surface side of the member. In this case, a light deflecting unit for deflecting the light emitted from the emission surface in a predetermined direction may be formed on the emission surface.

Similarly, a plurality of projections are formed on the back surface of the first light guide member to emit light in a condensed state toward the light reflecting sheet, and these projections are formed by the first projection. The contour shape perpendicularly projected to the back surface of the light guide member forms a triangle, one side of which is set substantially parallel to the incident end surface of the first light guide member, and the one side is closer to the vertex than the corresponding vertex. It may be located on the incident end face side of one light guide member.
In this case, a light deflecting means for deflecting the light emitted from the light emitting surface in a predetermined direction may be formed on the light emitting surface, and a contour shape perpendicularly projected on the rear surface forms a triangle. Alternatively, a plurality of second protrusions may be formed on the back surface of which one side is set to be substantially parallel to the incident end face, and whose vertex is located closer to the incident end face than the one side.

Further, the exit surface has a plurality of projections, which have light-collecting properties and direction controllability, and allow the light reflected on the back surface to exit from the exit surface. ,
The outline shape projected perpendicularly to the emission surface forms a triangle, one side of which is set substantially parallel to the incident end face, and the one side is located closer to the incident end face than the apex thereof. You may. In this case, the contour shape perpendicularly projected to the emission surface forms a triangle, one side of which is set substantially parallel to the incident end face, and the vertex for the one side is located closer to the incident end face than the one side. Two projections may be formed on the emission surface.

[0029]

1 to 1 show an embodiment of a flat lighting device according to the present invention incorporating a linear light projecting device according to the present invention.
Although the present invention will be described in detail with reference to FIG. 5, the present invention is not limited to such an embodiment, and can be further combined or applied to a technology in another field including a similar problem.

FIG. 1 shows a sectional structure of a first embodiment of a flat lighting device according to the present invention, and FIG. That is, the flat lighting device 1 in the present embodiment
Reference numeral 1 denotes a single point light source 12 such as a light emitting diode or a semiconductor laser, a first light guide member 14 having a rectangular rod shape to which an incident end face 13 is joined to the point light source 12, and a first light guide member. A linear light projecting device 17 having a first light reflecting sheet 16 covering portions other than the incident end surface portion 13 and the exit surface portion 14 of the light source 14 and an incident end surface portion 18 are connected to the exit surface portion 15 of the first light guide member 14. Second light guide member 19 in the form of a rectangular plate, and the second light reflection sheet 2 covering portions other than the incident end face portion 18 and the emission face portion 20 of the second light guide member 19.
And one.

It is desirable that the point light source 12 emits white light. However, a point light source having a two-color component may be used. In this case, a transparent material that transmits and reflects the two-color components is used. To the first and second light guide members 14, 19
For example, when the point light source 12 composed of blue and yellow components is used, the first and second light guide members 14 and 19 are made of blue transparent resin, and the color contrast corresponding to each luminance is increased. It is possible to get.

The first light guide member 14 in this embodiment is
An optically transparent material having a refractive index of about 1.4 to 1.7, for example, acrylic resin (PMMA) or polycarbonate (P)
C), and a pair of side end surfaces 22 parallel to each other.
And the point light source 1 formed on one end side of these side end face portions 22.
2, an incident end face portion 13 for introducing light from the light source 2, a reflection end face portion 23 located on the opposite side of the incident end face portion 13 and formed on the other end side of the side end face portion 22, and a pair of these side end faces It has an emission surface portion 15 for emitting light incident from the incident end surface portion 13 surrounded by the portion 22, the incident end surface portion 13, and the reflection end surface portion 23, and a back surface portion 24 located on the opposite side. The back surface portion 24 is set substantially parallel to the emission surface portion 15, but strictly speaking, the interval between the emission surface portion 15 and the back surface portion 24 is shorter with respect to the incident end surface portion 13 toward the reflection end surface portion 23. The back surface portion 24 has a tapered shape inclined from 0.5 degrees to 1 degree with respect to the emission surface portion 15.

The basic structure of the second light guide member 19 is also the first light guide member 19.
The light guide member 14 is formed of a transparent acrylic resin, and has a pair of side end surfaces 25 parallel to each other, and a first light guide member formed at one end of these side end surfaces 25. 14, an incident end surface 18 for introducing light from the exit surface 15, a reflective end surface 26 located on the opposite side of the incident end surface 18 and formed on the other end of the side end surface 25, The light emitting device includes an emission surface portion 20 that is surrounded by the pair of side end surface portions 25, the incident end surface portion 18, and the reflection end surface portion 26 and emits light incident from the incident end surface portion 18, and a back surface portion 27 located on the opposite side. The detailed structure may be exactly the same as the first light guide member 14 described below.

The first light reflecting sheet 16 described above is used for the first light reflecting sheet 16.
Of the light guide member 14 and the pair of side end surfaces 22
And the back surface portion 24, and the light emitted therefrom is reflected again into the first light guide member 14 and emitted from the emission surface portion 15 of the first light guide member 14, and the inner surface side is made of aluminum. The mirror processing by vapor deposition is performed, and the second light reflection sheet 21 is basically exactly the same as the first light reflection sheet 16.

FIG. 3 shows a cross-sectional structure taken along the line III-III in FIG. 1, and FIG. 4 schematically shows the back surface portion 24 of the first light guide member 14, and the appearance of the first convex portion 28 is shown. FIG. 5 is an enlarged view. That is, on the back surface portion 24 of the first light guide member 14,
The contour shape projected perpendicularly to the back surface 24 forms a triangle, and a pair of symmetric boundary surfaces 29 and these boundary surfaces 2
9, first isosceles triangular prism-shaped first protrusions 28 each having a second boundary surface 30 in contact with 9 and a triangular top surface 31 are randomly arranged.

A pair of boundary surfaces 29 of these first projections 28
Is emitted in a condensed state toward the outside of the first light guide member 14, that is, the surface of the first light reflection sheet 16, in which light reflected from the emission surface 15 side and incident on the first protrusion 28 is emitted. It has the function of condensing and emitting light. Also, the first convex portion 28
The second boundary surface 30 and the top surface 31 of the first light reflecting member 1 are emitted from the back surface 24 side of the first light guide member 14.
6 has a function of causing light reflected in a scattered state to enter the first projection 28.

As described above, the first convex portion 28 once emits a part of the light propagating in the first light guide member 14 toward the first light reflecting sheet 16 in a condensed state. The outgoing light is strongly reflected by the first light reflecting sheet 16 so that the back surface 24 of the first light guide member 14 and the second
Is introduced from the boundary surface 30 and the top surface 31 into the first light guide member 14, and is preferably 10 μm or more in consideration of light diffusion and ease of manufacturing.

Also, the boundary surfaces 29, 30 of the first convex portion 28
Is preferably inclined so that the angle φ between the vertical surface and the back surface 24 shown by the two-dot chain line in FIG. The bottom 32 of the second boundary surface 30 of the first projection 28 is set substantially parallel to the incident end surface 13.

On the exit surface 15 of the first light guide member 14,
An isosceles triangular prism 33 extending in a direction (horizontal direction in FIG. 1) orthogonal to the incident end face portion 13 and arranged along the width direction of the first light guide member 14 is formed as the light polarizing means of the present invention. And the prism 3 in the present embodiment.
No. 3 employs an apex angle of about 80 to 110 degrees. Instead of the prism 33, an irregular surface having a predetermined radius of curvature may be formed in a waveform, or a convex spherical lens array having a predetermined radius of curvature may be provided on the emission surface 15 of the first light guide member 14.

By the way, light entering the incident end face 13 of the first light guide member 14 at an incident angle γ, that is, an angle formed between the light exit surface 15 and the light beam at γ constitutes the first light guide member 14. Refractive index n (in the case of the acrylic resin of this embodiment,
n = 1.49)

[0041]

## EQU1 ## The light travels through the first light guide member 14 within the range of the incident angle γ satisfying 0 ≦ | γ | ≦ sin ⁻¹ (l / n). Part of the light traveling toward the back surface portion 24 enters the first convex portion 28 and exits from the pair of boundary surfaces 29 to the outside of the first light guide member 14 as it is, and the rest is the back surface. The light is totally reflected by the portion 24 and propagates to the emission surface 15 side.

The light leaked from the back surface 24 or the first convex portion 28 to the outside of the first light guide member 14, that is, stray light is reflected by the pair of boundary surfaces 29 and the like, but is reflected by the first light. Due to the presence of the reflection sheet 16, the light enters the first light guide member 14 again from the back surface 24, while the second boundary surface 30 and the top surface 31 of the first protrusion 28 again enter the first protrusion 28. And a part of the light is totally reflected by the pair of boundary surfaces 29 and propagates toward the emission surface portion 15, and finally all from the emission surface portion 15 toward the incidence end surface portion 18 of the second light guide member 19. Emit.

As shown in FIG. 6 showing the planar shape of the first convex portion 28 as viewed from the rear surface portion 24 side, the light ray L entering the first convex portion 28 from the exit surface portion 15 side is formed by a pair of boundary surfaces. In order to emit light out of the first light guide member 14 without total reflection at 29, considering the light beam L traveling on a plane parallel to the back surface portion 24, the light beam L with respect to the pair of boundary surfaces 29 is considered. Angle of incidence θ
Then

[0044]

It is necessary to satisfy θ ≦ sin ⁻¹ (1 / n). Here, if the pi is π,
The angle α ₁ formed by the pair of boundary surfaces 29 is α ₁ = 2 ｛(π / π
2) Since -γ｝,

[0045]

Α ₁ ≧ π−2 sin ⁻¹ (1 / n) As a practical matter, the plane including the optical path of the light beam L is inclined with respect to the back surface 24, and a pair of Is formed between the light ray L and the back surface 2
Tan (α / 2) = cos β · ta
because it is n (α _1/2),

[0046]

It can be seen that it is only necessary to satisfy α ≧ tan ⁻¹ [cos β · tan ｛π−2 sin ⁻¹ (1 / n)｝].

Specifically, in the present embodiment in which an acrylic resin having a refractive index n of 1.49 is employed as the first light guide member 14, α needs to be about 78 degrees or more. Also, as a practical matter, the plane including the optical path of the light beam L is inclined with respect to the back surface portion 24, and when the angle between the light beam L and the back surface portion 24 is β, the light beam emitted from the light outgoing surface portion 15 side In order for L to be emitted from here without total reflection at the boundary surface 29,

[0048]

It is necessary to satisfy β ≦ sin ⁻¹ (l / n). Here, β = sin ⁻¹ (l / n)
In this case, the above-mentioned α in this embodiment is about 78 degrees, and α ₁ is 95 degrees. Therefore, it is preferable to form the first convex portion 28 so that α falls within the range of 78 degrees to 95 degrees. .
However, as a practical problem, light that cannot be emitted from the pair of boundary surfaces 29 returns to the inside of the first light guide member 14 by internal reflection, and a scattering element due to the internal structure of the first light guide member 14 is considered. , Α are set so as to fall within the range of 60 degrees to 120 degrees, thereby substantially achieving the purpose of the present invention.

Therefore, most of the incident light beam L having an incident angle γ of 42 degrees or less is totally reflected by the back surface portion 24 and propagates to the emission surface portion 15 side, but a part thereof is transmitted from the first convex portion 28 to the first convex portion 28. The light exits outside the first light guide member 14. The incident light beam L whose incident angle γ exceeds 42 degrees is emitted from the back surface portion 24 to the outside of the first light guide member 14 in a condensed state. The light enters the light guide member 14 in a diffused state, and finally enters the second light guide member 19 from the emission surface 15.
The light exits toward the incident end face portion 18.

The energy of the light incident on the first light guide member 14 from the point light source 12 decreases as it travels through the first light guide member 14. It is necessary to gradually change the occupancy of the first protrusion 28 protruding from the back surface 24. Specifically, the ratio of the area of the first convex portion 28 to the unit area of the rear surface portion 24 (hereinafter referred to as “the area ratio of the first convex portion 28”) is set so that the reflected light emitted from the emission surface portion 15 has uniform brightness over the entire emission surface portion 15. , Which will be referred to as an occupancy) indicates the relationship between the position of the back surface 24 along the traveling direction of light from the point light source 12 (to the right in FIG. 1) and the occupancy of the first protrusion 28. As shown in FIG.
The occupancy is set so as to be larger on the side.

In this case, the light exiting surface portion 15 of the first light guide member 14 which is close to the incident end surface portion 13 has a tendency that the light from the point light source 12 is directly transmitted to increase the luminance. First convex portion 2 on the back surface portion 24 close to
8 is set to be smaller than the subsequent portion. Similarly, the emission surface portion 15 of the first light guide member 14 that is close to the reflection end surface portion 23 has a tendency that the reflected light from the reflection end surface portion 23 is transmitted and the luminance is high, and therefore the emission surface portion 15 is close to the reflection end surface portion 23. The occupation ratio of the first convex portion 28 on the rear surface portion 24 is set to be smaller than that of the subsequent portion.

Since the light emitting area of the point light source 12 is substantially shorter than the width dimension of the incident end face portion 13 of the first light guide member 14, the light is incident on both end portions in the width direction of the first light guide member 14. Tend to be insufficient. For this reason, it is desirable that the occupation ratio of the first protrusions 28 at both end portions in the width direction of the emission surface portion 15 of the first light guide member 14 be set to be relatively larger than other portions. In any case, in this embodiment, the maximum value of the occupation ratio of the first convex portion 28 is set to about 70%, but it is naturally possible to set the occupancy to a value higher than about 70%.

In the above-described embodiment, the first convex portion 28 is formed in a triangular prism shape, but may be formed in a triangular pyramid shape.

FIG. 8 shows the appearance of another embodiment of the first convex portion of the first light guide member. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals. Stop and duplicate description will be omitted. That is, the first convex portion 34 in the present embodiment has an isosceles triangular pyramid shape having a pair of symmetric boundary surfaces 29 and an inclined conical surface 35, and is further projected perpendicularly to the back surface portion 24. A second convex portion 36 having a triangular contour is formed. The second convex portion 36 in the present embodiment is combined so as to be in contact with and opposed to the base 32 of the first convex portion 28 of the previous embodiment, and the vertex with respect to the base 32 set substantially parallel to the incident end face portion 13. 3
7 is located closer to the incident end face portion 13 than the bottom side 32, and has an isosceles triangular pyramid shape having a pair of symmetric boundary surfaces 38 and an inclined cone surface 39.

Accordingly, these convex portions 34 and 36 have a rhombic outline shape projected perpendicularly to the back surface portion 24,
The first convex portion 34 and the second convex portion 36 are set in a mirror image relationship with the base 32 as the axis of symmetry. In this case, the length of the oblique side of one boundary surface 29 may be different from the length of the oblique side of the other boundary surface 38.

The first convex portion 34 mainly includes the incident end face 1
3 (see FIG. 3), while exhibiting the above-described function with respect to light traveling toward the reflection end face 23 (see FIG. 3).
The second convex portion 36 is formed from the reflection end surface portion 23 side to the incident end surface portion 1.
The above-described function is exhibited for light returning to the first light guide member 14 toward the third side. For this reason, it is not necessary to incline the back surface portion 24 with respect to the emission surface portion 15 in a tapered shape as in the previous embodiment, and it is possible to set a uniform plate thickness on both the incident end surface portion 13 side and the reflection end surface portion 23 side. It is possible.

As described above, in this embodiment, the reflection end face portion 23
The light returning to the inside of the first light guide member 14 from the side toward the incident end face portion 13 is also actively led out of the emission surface portion 15, so that the light is directed in the direction directly facing the emission surface portion 15 of the first light guide member 14. Strong light is emitted. In this case, the second convex portion 36 is arranged separately from the first convex portion 34,
It is also possible to arrange such that the distribution state is different from the distribution state of the convex portions 34, for example, the distribution is increased toward the incident end face portion 13 side. From the light exit surface 15 of the light guide member 14.

In the above-described embodiment, the first convex portion 34 and the second convex portion 36 are set in a combined shape. However, these inclined conical surfaces 35, 39 are set in parallel with the back surface portion 24. In this case, the first light guide member having the same efficiency as that of the first embodiment can be obtained.

FIG. 9 shows the appearance of another embodiment of the first projection of the first light guide member. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals. Stop and duplicate description will be omitted. That is, the second convex portion 40 in the present embodiment is formed by the two pairs of boundary surfaces 29 and 38 and the back surface portion 2.
4 (see FIG. 3), and has a top surface 31 parallel to the surface 4 and is formed in a truncated quadrangular pyramid shape. One of these diagonals C
₁ is orthogonal to the other diagonal line C ₂ ,
3 (see FIG. 3). In this case, the scattered light reflected by the first light reflection sheet 16 (see FIG. 3) enters the first light guide member 14 (see FIG. 3) from the back surface 24 and the first light guide member 14 (see FIG. 3). The light enters the projection 40.

In the above-described embodiment, the incident end face 13 of the first light guide member 14 is formed in a plane perpendicular to the optical axis of the point light source 12. It is also possible to provide a desired optical surface for positive adjustment. Further, in the above-described embodiment, the convex portion 2 for emitting the light toward the first light reflecting sheet 16 in a condensed state.
8, 34, 36, 40 are connected to the back surface 2 of the first light guide member 14.
4, a plurality of first convex portions having light-collecting properties and directional controllability and allowing the light reflected on the back surface portion 24 to be emitted from the emission surface portion 15 are formed on the emission surface portion 15. It may be.

FIG. 10 schematically shows a cross-sectional structure of another embodiment of the linear light projection device according to the present invention, in which the first convex portion 42 of the linear light projection device 41 in this embodiment is extracted. The enlarged shape is shown in FIG. That is, the first light guide member 4
3 is a concave lens having an optical axis inclined with respect to the optical axis of the point light source 12, and diffuses light incident from the point light source 12 into the first light guide member 43 while diffusing the light. Although the concave lens has a function of deflecting more strongly toward the portion 24, the concave lens may be a cylindrical concave lens having a focal line perpendicular to the paper surface of FIG. 10, or, instead of these concave lenses and cylindrical concave lenses, Set these focal lengths (focal lengths) to infinity,
It is also possible to use a plane inclined with respect to the emission surface section 15. Further, the optical axis of the concave lens or the cylindrical concave lens may be set to be coaxial with the optical axis of the point light source 12 along the longitudinal direction of the first light guide member 43.

In this embodiment, the first convex portion is not formed on the back surface portion 24, and a flat mirror surface is provided. Also, the back surface portion 2 is arranged such that the distance between the exit surface portion 15 and the back surface portion 24 becomes gradually shorter toward the reflection end surface portion 23 side than the incident end surface portion 44 side.
4 is formed with a curved surface such as an arc surface or a paraboloid, and the reflection end surface portion 23 is formed in a linear shape, so that the light is more strongly deflected by the exit surface portion 15 toward the reflection end surface portion 23 side. .

The light exit surface 15 of the first light guide member 43 has
The contour shape projected perpendicularly to the light exit surface 15 forms a triangle, and a pair of symmetrical vertical pyramids 45 and inclined pyramids 46
The first convex portions 42 having an isosceles triangular pyramid shape having random numbers are randomly arranged. The vertical conical surface 45 of the first convex portion 42 is
Although it is preferable that the light exit surface 15 is perpendicular to the light exit surface 15, it is necessary to set an appropriate draft with respect to the mold at the time of manufacturing the first light guide member 43.
May be set to exceed 90 degrees. The bottom side 47 of the inclined conical surface 46 of the first convex portion 42 is set substantially parallel to the incident end surface portion 44.

The planar shape of the first convex portion 42 is substantially the same as the first convex portion 28 of the previous embodiment shown in FIG.
FIG. 12 schematically shows the side surface shape of the emission surface section 15. That is, in order for the light beam L entering the first convex portion 42 to be emitted from the pair of vertical conical surfaces 45 without being totally reflected by the pair of vertical conical surfaces 45, the refractive index n is 1.49 as in the previous embodiment. When the acrylic resin is used as the first light guide member 43, in order to improve the light collecting property, the angle α between the plane including the optical path of the light ray L and the pair of vertical pyramids 45 is 85 to 135 degrees. Is desirably within the range. Further, as a practical matter, the plane including the optical path of the light ray L is inclined with respect to the light exit surface 15, and when the angle between the light ray L and the light exit surface 15 is β, this is the total reflection at the vertical conical surface 45. In order to exit from here without

[0065]

It is necessary to satisfy β ≦ (3/2) · sin ⁻¹ (1 / n). Where β = (3/2) · sin
^{In the case of -1} (l / n), the above-mentioned α in this embodiment is about 1
Since the angle is 36 degrees, it is preferable to form the first protrusion 42 so that α falls within the range of 95 degrees to 136 degrees.

That is, the above-described first convex portion 42 functions to deflect the direction of the light emitted from the emission surface 15 more vertically.

In the embodiment described above, the first light guide member 43
Is formed as a concave lens, but may be formed as a convex lens. Further, it is also possible to form a prism on the back surface portion 24 to control the deflection of light more strongly.

FIG. 13 shows a cross-sectional structure of another embodiment of such a linear light projecting device according to the present invention, and FIG. 14 is an enlarged view of the first convex portion 42 shown in FIG. FIG. 15 shows a cross-sectional structure taken along the line -XV, in which members having the same functions as those in the previous embodiment are denoted by the same reference numerals, and redundant description is omitted. That is, the incident end face 5 of the first light guide member 49 of the linear light projection device 48 in the present embodiment.
Numeral 0 denotes a convex lens that is coaxial with the optical axis of the point light source 12, and condenses light from the point light source 12 and guides the light into the first light guide member 49. FIG.
10 may be used as a cylindrical convex lens having a focal line perpendicular to the paper surface. The optical axes of these convex lenses and the cylindrical convex lenses are inclined with respect to the optical axis of the point light source 12 as in the embodiment shown in FIG. May be more strongly deflected to the back surface portion 24 side.

On the exit surface 15 of the first light guide member 49,
A second convex portion 51 having a rhombic outline shape projected perpendicularly to the emission surface portion 15 is formed. The second projection 51 in the present embodiment is the same as the first projection 42 in the previous embodiment.
The vertex 52 with respect to the base 47 set substantially parallel to the reflection end face 23 is located closer to the incident end face 50 than the base 47, and a pair of symmetrical vertical It is an isosceles triangular pyramid having a conical surface 53 and an inclined conical surface 54. In the present embodiment, the first convex portion 42 and the second convex portion 51 are set to have a mirror image relationship with the base 47 as the axis of symmetry.
The length of the hypotenuse of the other vertical conical surface 53 may be different from the length of the hypotenuse of No. 5, and it is desirable that the hypotenuse is symmetric with respect to a diagonal line C ₂ orthogonal to the base.

The second convex portion 51 mainly functions to guide the light returning inside the first light guide member 49 from the reflection end surface portion 23 side to the incident end surface portion 50 side to the outside of the emission surface portion 15. . For this reason, it is not necessary to incline the back surface portion 24 in a tapered shape with respect to the emission surface portion 15 as in the previous embodiment, and the first end surface portion 50 side and the reflection end surface portion 23 side have the first inclination.
Can be set to have a uniform plate thickness.

The back surface 2 of the first light guide member 49
4, a triangular prism-shaped prism 55 having a light reflecting function, which extends in the longitudinal direction of the first light guide member 49 and is arranged in a direction perpendicular to the first light guide member 49, is formed as a light polarizing means of the present invention. And the first and second projections 4
2, 51 and the prism 55, the first light guide member 4
9 is controlled so as to emit light in a substantially vertical direction from the emission surface 15 of the light emitting device 9.

As described above, in this embodiment, the reflection end face portion 23
Since the light returning inside the first light guide member 49 from the side to the incident end face 50 side is also positively led out from the output face 15, the second light facing the output face 15 of the first light guide member 49. The light having a high luminance is emitted to the incident end face portion 18 (see FIG. 1) of the light guide member 19 of FIG.

In the above-described embodiment, the shape is such that the first convex portion 42 and the second convex portion 51 are combined. However, by setting the inclined conical surfaces 46 and 54 to be parallel to the exit surface portion 15, the square shape is obtained. It is also possible to make it columnar (see FIG. 9),
Also in this case, it is possible to obtain an efficient first light guide plate similar to that of the previous embodiment. In addition, the second convex portion 51 is separately arranged separately from the first convex portion 42, and a distribution state different from the distribution state of the first convex portion 42, for example, the incident end face portion 5.
It is also possible to arrange so that the number increases on the zero side, so that light returning from the reflection end face portion 23 side can be more uniformly led out from the emission surface portion 15 of the first light guide member 49.

[0074]

According to the linear light projection device of the first embodiment of the present invention, since a single point light source is used, power consumption can be suppressed to a minimum and the entire device can be made compact. can do. In addition, since a plurality of convex portions are formed on the back surface of the light guide member so that a part of the light incident from the incident end surface of the light guide member is emitted toward the light reflecting sheet in a condensed state, the light guide member is formed. , It is possible to emit high-luminance light with a uniform distribution from the exit surface of the light emitting element.

According to the linear light projecting device of the second embodiment of the present invention, the plurality of convex portions having the light condensing property and the direction controllability and for emitting the light reflected on the back surface from the light emitting surface. Is formed on the emission surface of the light guide member, so that high-luminance light can be emitted from the emission surface of the light guide member with a uniform distribution.

In the linear light projecting devices according to the first and second embodiments of the present invention, the convex portions are set such that the farther from the incident end face of the light guide member, the larger the ratio of the back surface to the unit area becomes. In this case, the amount of light emitted from the emission surface can be made uniform along the longitudinal direction of the emission surface.

According to the flat lighting device of the third embodiment of the present invention, since a single point light source is used, power consumption can be minimized and the whole device can be made compact. .

Further, the first convex portion for outputting a part of the light incident from the incident end face of the first light guide member toward the first light reflecting sheet in a condensed state is formed by the first convex portion. When a plurality of light members are formed on the back surface, high-intensity light can be emitted from the emission surface of the second light guide member with a uniform distribution.

Similarly, the first light guide member has a plurality of first projections, which have a light collecting property and a direction control property, and allow the light reflected on the back surface to be emitted from the emission surface. Also in the case of forming, high-luminance light can be emitted from the emission surface of the second light guide member with a uniform distribution.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic structure of an embodiment of a flat lighting device according to the present invention.

FIG. 2 is an exploded perspective view of the flat lighting device shown in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a plan view schematically showing the appearance of the back surface of the first light guide member in the embodiment shown in FIG.

FIG. 5 is an enlarged perspective view extracting and showing an appearance of a first convex portion in the embodiment shown in FIG. 1;

FIG. 6 is a plan view of a first protrusion in the embodiment shown in FIG. 1;

FIG. 7 is a graph showing the relationship between the position of the back surface of the first light guide member from the incident end face to the reflective end face and the occupancy of the first protrusion per unit area.

FIG. 8 is an enlarged perspective view extracting and showing the appearance of another embodiment of the first convex portion and the second convex portion of the first light guide member.

FIG. 9 is an enlarged perspective view extracting and showing the appearance of another embodiment of the first convex portion and the second convex portion of the first light guide member.

FIG. 10 is a sectional view schematically showing a schematic structure of still another embodiment of the linear light projection device according to the present invention.

11 is an enlarged perspective view extracting and showing the appearance of a first convex portion in the embodiment shown in FIG.

FIG. 12 is a conceptual diagram schematically showing a side surface shape of a first light guide member in the embodiment shown in FIG.

FIG. 13 is a sectional view schematically showing a schematic structure of still another embodiment of the linear light projection device according to the present invention.

FIG. 14 is an enlarged perspective view extracting and showing the appearance of a first convex portion and a second convex portion in the embodiment shown in FIG. 13;

FIG. 15 is a sectional view taken along the line XV-XV in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Planar illumination device 12 Point light source 13 Incident end face part 14 1st light guide member 15 Emission face part 16 1st light reflection sheet 17 Linear light projection device 18 Incident end face part 19 2nd light guide member 20 Emission face part 21 First 2 light reflection sheet 22 side end surface 23 reflection end surface 24 back surface 25 side end surface 26 reflection end surface 27 back surface 28 first convex portion 29 boundary surface 30 second boundary surface 31 top surface 32 bottom 33 prism 34 First convex portion 35 Inclined conical surface 36 Second convex portion 37 Vertex 38 Boundary surface 39 Inclined conical surface 40 Second convex portion 41 Linear light projecting device 42 First convex portion 43 First light guide member 44 Incident end face 45 Vertical conical face 46 Inclined conical face 47 Bottom 48 Linear light projecting device 49 First light guide member 50 Incident end face section 51 Second convex portion 52 Vertex 53 Vertical conical face 54 Inclined conical face 55 Prism L Ray α ₁ Angle between a pair of boundary surfaces β Angle between the ray and the back surface C ₁ , C ₂ Diagonal

Claims (11)

[Claims] A single point light source for projecting light; an incident end face for introducing light from the point light source; an emitting face for emitting light incident from the incident end face; A light guide member having a back surface located on the side opposite to the emission surface portion, wherein the incident end surface portion is located on one end side of the emission surface portion and the back surface portion; and the incident end surface portion of the light guide member and A light reflecting sheet covering a portion other than the light emitting surface, and a plurality of convex portions for emitting light in a condensed state toward the light reflecting sheet are formed on the back surface of the light guide member. These convex portions have a triangular outline shape projected perpendicularly to the back surface of the light guide member, and one side thereof is set substantially parallel to the incident end face portion of the light guide member, and the one side is Is closer to the light guide member than to the vertex for this. Linear light projection apparatus characterized by being located on the end surface portion side. 2. The linear light projection according to claim 1, wherein a light deflecting unit for deflecting light emitted from the light emitting surface in a predetermined direction is formed on the light emitting surface. apparatus. 3. A contour projected perpendicular to the back surface forms a triangle, one side of which is set substantially parallel to the incident end face, and a vertex with respect to the one side is larger than the one side. 3. The linear light projection device according to claim 1, wherein a plurality of second convex portions located on the side are formed on the back surface portion. 4. 4. A single point light source for projecting light, an incident end face for introducing light from the point light source, an emitting face for emitting light incident from the incident end face, A light guide member having a back surface located on the side opposite to the emission surface portion, wherein the incident end surface portion is located on one end side of the emission surface portion and the back surface portion; and the incident end surface portion of the light guide member and A light reflecting sheet covering a portion other than the emission surface portion, the emission surface portion has a light collecting property and a direction controllability, and the light reflected on the back surface portion is emitted from the emission surface portion. A plurality of convex portions are formed, and these convex portions have a triangular contour shape projected perpendicularly to the emission surface portion, one side of which is set substantially parallel to the incident end surface portion, and the one side corresponds to the triangle. Located closer to the incident end face than the vertex Linear light projection apparatus according to claim Rukoto. 5. An outline shape projected perpendicularly to said emission surface portion forms a triangle, one side of which is set substantially parallel to said incident end surface portion, and a vertex with respect to said one side is larger than said one side in said incident end surface portion. 5. The linear light projection device according to claim 4, wherein a plurality of second convex portions located on the side are formed on the emission surface portion. 6. 6. A single point light source for projecting light, an incident end face for introducing light from the point light source, an emitting face for emitting light incident from the incident end face, A first light guide member having a back surface located on the side opposite to the emission surface portion, wherein the incident end surface portion has a rod-like shape located on one end side of the emission surface portion and the back surface portion; A first light-reflecting sheet that covers a part other than the incident end surface and the exit surface of the member; an incident end surface for connecting to the exit surface of the first light guide member to introduce light; An emission surface portion for emitting light incident from the incident end surface portion, and a back surface portion opposite to the emission surface portion, and the incident end surface portion is located at one end side of the emission surface portion and the back surface portion. A plate-shaped second light guide member, and a front of the second light guide member Flat illumination device, characterized in that it comprises a second light reflecting sheet covering the portion other than the incident end face and the emitting surface. 7. The back surface of the first light guide member,
A plurality of projections for emitting light in a condensed state toward the light reflection sheet are formed, and the projections have a contour shape perpendicularly projected to the back surface of the first light guide member. Form a triangle, one side of which is set substantially parallel to the incident end face portion of the first light guide member, and the one side is closer to the incident end face portion side of the first light guide member than a vertex corresponding thereto. The flat lighting device according to claim 6, wherein the flat lighting device is located. 8. The flat lighting device according to claim 7, wherein a light deflecting unit for deflecting light emitted from the light emitting surface in a predetermined direction is formed on the light emitting surface. 9. A contour which is perpendicularly projected to the back surface and forms a triangle, one side of which is set substantially parallel to the incident end face, and a vertex with respect to the one side is larger than the one side. 9. The flat lighting device according to claim 7, wherein a plurality of second convex portions located on the side are formed on the back surface portion. 10. 10. A plurality of projections having a light collecting property and a directional control property for emitting light reflected on the back face from the emission face are formed on the emission face. The part has a triangular outline shape projected perpendicularly to the emission surface part, one side of which is set substantially parallel to the incident end surface part, and the one side is positioned closer to the incident end surface part than the vertex corresponding thereto. The flat illuminating device according to claim 6, wherein: 11. A contour which is projected perpendicular to the emission surface portion and forms a triangle, one side of which is set substantially parallel to the incident end surface portion, and a vertex for the one side is set to the incident end surface portion more than the one side. 11. A plurality of second convex portions located on the side are formed on the emission surface portion.
A flat lighting device according to claim 1.