JP2000260215A - Lighting system and light guide system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve contrast and to prevent unevenness in light quantity by providing a configuration so that a reflective light from a light source does not travel toward an observer. SOLUTION: A streaky uneven shape 108 is irradiated at the edge thereof with a light emitted from a light source 104, the type thereof being a point source so as to decrease the light traveling straight to exit from the opposite edge and to utilize a slantingly incident light as an illumination light. Since the slantingly incident light is guided to a light diffusing plate 107 at an end to be irregularly reflected, a light traveling in the direction of the right angle to the streaky uneven shape 108 is eliminated, preventing an observer from seeing a ring-shaped or streak-shaped striped pattern generated by the interference of the light and resulting in an illumination with good contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device, and more particularly to an illuminating device capable of illuminating an illuminated surface by disposing a transparent plate capable of emitting light close to the illuminated surface. It relates to an improved and light guiding system.

[0002]

2. Description of the Related Art When illuminating an illuminated surface having no light transmission, such as a bulletin board, a light component in the direction of the illuminated surface is taken out of the illuminating light incident from just beside as an illuminating device that can be used. There was one that made the surface illuminable.

For example, Japanese Patent Application Laid-Open Nos. Hei 6-289391 and Hei 6-324331 disclose a transparent light guide plate 50 provided with a line-shaped uneven shape 53 as shown in FIGS. A lighting device provided with a light source 40 on the side end face of the lighting device is described.

[0004] Light emitted from the light source 40 is incident from the side end surface of the light guide plate 50, and the front surface 52 and the back surface 51 of the light guide plate 50 are provided.
Repeat reflection between and. Of the light that is repeatedly reflected, light that has entered the side wall 55 of the uneven shape 53 is not reflected because of a large incident angle, and is emitted to the surface to be irradiated and used as illumination light.

[0005]

However, in this conventional illuminating device, when the surface to be illuminated is observed through the light guide plate, there is a disadvantage that a streak of light runs on the light guide plate. Since light streaks are visible on the light guide plate, the illuminated surface becomes difficult to see and the contrast is reduced. This is because
It is conceivable that light is reflected at the base of the uneven shape.

That is, as shown in FIG. 9, the original illumination light emitted to the surface to be illuminated is reflected by the indirect light LI3 propagated while being reflected between the front surface 52 and the back surface 51, and reflected by the light source. The direct light LD3 arriving without reaching the side wall 55 is emitted to the irradiated surface.

However, among the light propagating in the light guide plate,
As shown by the indirect light LI1 and LI2 and the direct light LD1 and LD2, there are some which are reflected at the boundary 56 at the base of the uneven shape 53.

[0008] Regardless of the manufacturing method used to form the concavo-convex shape, the boundary portion of the concavo-convex shape usually has some roundness R. This roundness R microscopically forms a light reflection surface. For this reason, the light from the light source is reflected at the boundary 56 of the uneven shape 53, and the reflected light reaches the eyes of the observer. Since the uneven shape 53 is formed by arranging the wall shapes at predetermined intervals, the reflection points of the boundary line 56 are arranged in a line along the projection line of the line connecting the viewpoint and the light source 40 to the light guide plate 50. And this is recognized as a streak of light.

An object of the present invention is to provide an illuminating device and a light guide system with good contrast by providing a configuration in which reflected light of a light source is not emitted toward an observer in order to solve such a problem. .

[0010]

In order to achieve this object, the invention according to claim 1 is constituted by a transparent thin-walled and rectangular plate material, and in the contour of the plate material, is parallel to two sides opposed to each other. A light guide plate having a streaky uneven shape, and a light source disposed on an end face side corresponding to at least one end of the streaky uneven shape and emitting light to be introduced into the light guide plate from the end face; And a first light diffusing plate arranged corresponding to at least one of the end faces corresponding to the two sides of the light guide plate, for preventing leakage of light in the light guide plate and reflecting the light. And

According to a second aspect of the present invention, in the first aspect of the present invention, the light source is a point light source disposed at one or a plurality of locations on the end face.

According to a third aspect of the present invention, there is provided a light guide plate which is formed of a transparent thin and rectangular plate, and has an uneven shape formed in a streak shape parallel to two sides facing each other in a contour of the plate; A plurality of point light sources that are intermittently arranged on an end face side corresponding to at least one end of the streak-like uneven shape and emit light to be introduced into the light guide plate from the end face, and extend over the entire circumference of the light guide plate. It is provided in a portion other than the arrangement position of the point light source on the end face, and prevents leakage of light in the light guide plate,
And a second light diffusing plate that reflects light.

According to the first aspect of the present invention, the light guide plate is arranged so that the uneven shape is in contact with the original surface. here,
Of the light emitted from the light source, the light that travels straight along the streaky uneven shape has no role as illumination, and the light that enters obliquely enters the uneven shape and is guided to the tip of this unevenness. The light is emitted to irradiate the original.

Further, light that does not pass through the uneven shape and reaches the end surface parallel to the streaky uneven shape is reflected by the first light diffusing plate and then enters the uneven shape.

As a result, except for a part of the light traveling straight,
Since the light enters the concave / convex shape from an oblique direction, the light reflected toward the observer at the corner (boundary) of the rising portion of the side surface of the concave / convex shape also exits in the oblique direction of the light guide plate and is observed by the observer. Will not enter.

Therefore, no stripes are visible.
The observer can see the uniformly illuminated document.

According to the second aspect of the present invention, since a point light source is used as the light source, most of the light entering the light guide plate is inclined with respect to the incident end face, so that there is little wasted light. Thus, the light from the light source can be used effectively.

According to the third aspect of the present invention, since the second light diffusing plates are provided on all of the end faces except for the point light sources, most of the light incident on the light guide plate can be used. it can.

Further, the present invention is a novel light guide system realized by the lighting device. That is, the first mode includes a light source, and a light guide that emits light from the light source means toward the irradiated surface and guides reflected light from the irradiated surface to the observation side. In the optical system, a reflector is provided for the light guide, and secondary light reflected by the reflector out of the light from the light source is emitted from the light guide toward the irradiated surface. It is characterized by the following.

The second mode is characterized in that the light source is a point light source and the reflector functions to diffuse light from the point light source into the light guide. In still another embodiment, the light guide includes a linear projection, the point light source is provided at an end in a direction in which the linear projection extends, and the reflector emits light from the point light source. It is characterized by being configured to reflect light toward the linear projection.

According to this light guide system, it is possible to diffuse the light of the point light source into the light guide by the reflector, and to guide the light, so that the light from the point light source is directly guided to the linear light source. It is possible to prevent the occurrence of an annular striation caused by the interference between the point light source and the linear projection.

[0022]

1 and 2 show a lighting apparatus 100 according to the present embodiment. FIG. 1 is a perspective view of the lighting device 100, and FIG. 2 is a plan view of the lighting device 100. The lighting device 100 of the present embodiment includes a light guide plate 102,
It is composed of a light source 104 and a light diffusion plate 107.

The light guide plate 102 has a thin transparent rectangular shape, and has an optical structure capable of emitting a part of the illumination light incident from the end face (long side) in the direction of the irradiated surface. More specifically, as shown in FIG. 1, the light guide plate 102 has a planar first surface 102A and a second surface 102B having an uneven shape 108.
And The first surface faces the observer, and the second surface faces the irradiated object.

The uneven shape 108 has a wall shape composed of an upper surface (top surface) 108A and side surfaces (sidewall surfaces) 108B.
The longitudinal direction is the end face 102L of the light guide plate 102 (long side)
Is formed so as to be perpendicular to.

In order to improve the light use efficiency, it is preferable to set the ratio of the width of the upper surface 108A to the width of the side surface 108B (the height of the uneven shape 108) to be about 1: 1. preferable.

That is, the luminance of the irradiation light is reduced to the second surface 102B.
Of the concave and convex portions 108 as viewed from the light source 104 side.
This is performed by adjusting the area density of 8B.

The light guide plate 102 is made of a material having a higher refractive index than the substance on the light emitting side (air in the present embodiment) and having a light transmitting property. For example, it is formed of a transparent resin such as an acrylic resin, a polycarbonate resin or an amorphous napolyolefin, an inorganic transparent material such as a glass, or a composite thereof.

The light guide plate 102 is manufactured by injection molding if it is a resin material, and is manufactured by irradiating light if it has photocurability. In the case of glass or the like, etching is performed.
Further, it can also be manufactured by attaching a light diffusing shaped object such as a film having an uneven shape on a resin plate or a glass plate.

The light source 104 is a point light source.
4A and a pair of power supply terminals 104B, which are intermittently arranged at a predetermined pitch along the end face 102L (long side) of the light guide plate 102. That is, the point light sources are arranged facing both ends of the uneven shape 108. This light source 10
Numeral 4 is configured to emit light by supplying power from a power supply (not shown) via a power supply terminal 104B.

As the point light source, for example, a light emitting diode (LED), a semiconductor diode, an incandescent lamp, an EL (electroluminescence) element lamp can be applied. When used for illumination, the emission wavelength is set to a wavelength of visible light of about 380 nm to 700 nm.

The light diffusing plate 107 is attached to both end surfaces 102S on the short side, which are perpendicular to the end surface 102L on which the light source 104 is disposed. That is, the light diffusing plate is fixed to the pair of opposite sides 107 of the light guide plate, where there is no uneven end.

The light diffusing plate 107 has a color (for example, white) having a high reflectance on the surface to be attached to the light guide plate 102.
It has a role to diffusely reflect light in the light guide plate 102.
In addition, as the light diffusion plate 107, a white PET film,
An aluminum vapor-deposited film or the like is applicable. In addition,
As the light diffusing plate 107, the coating film can have a function as a light diffusing plate by coating the end face 102L in white as well as pasting.

Here, the light emitted from the light source 104 is
Although the light enters the light guide plate 102 from the end face 102L, since the light is divergent light, the downward light (in the direction of the second surface 102B where the unevenness 108 is formed) is emitted by the unevenness 108 as described with reference to FIG. Reflected by the light guide plate 102
To the original surface (illuminated surface) on which the document is superimposed. For this reason, this light irradiates the document surface (the irradiation target), and the observer can recognize the reflected light from the irradiation target irradiated with the light.

On the other hand, the light guide plate 1 faces upward from the horizontal (light guide plate 1).
02 (in the direction of the first surface 102A) reaches the end surface 102S on which the light diffusion plate 107 is provided. Therefore, the light is irregularly reflected, guided at a predetermined angle with respect to the concave-convex shape 108, and irradiates the original surface, so that the observer can recognize the reflected light from the original, which is the irradiated object. it can.

As described above, all the light used as the illumination light is obliquely incident on the concave-convex shape 108. Therefore, the rising corner of the side surface 108A of the concave-convex shape 108 (the boundary shown in FIG. 3). In the portion 108C), the light reflected in the direction of the first surface 102A of the light guide plate 102 is in a direction deviating from the region above the light guide plate 102, and does not enter the eyes of the observer. Contrast does not interfere.

The operation of the present embodiment will be described below.

When power is supplied to the light source 104, the light source 10
4 emits light. This light enters the light guide plate 102 from the end face 102L.

The light incident on the light guide plate 102 is obliquely incident on the end face 102L, impinges on the concave / convex shape 108 of the light guide plate 102, and irradiates the original surface, which is an object to be illuminated, with the light. Regardless of the uneven shape 108 of the light plate 102,
It is split into light reaching the end face 102S.

The light reaching the end face 102S is irregularly reflected by the light diffusing plate 107 attached (applied) to the end face 102S, and consequently enters the area of the uneven shape 108 at a predetermined angle, and is used as original irradiation light. .

Here, when the observer looks at the document, the light reflected at the rising corner (boundary portion 108C) of the side surface 108B of the concavo-convex shape 108 reaches the observer's eyes in the past, and that part is the other part. In some cases, the light amount was different, so that it sometimes looked like a striped pattern. However, in the present embodiment,
Since the light source 104 is disposed at the streak-like end of the uneven shape 108, as shown in FIG. 4, the light that is orthogonally incident on the uneven shape 108 deviates from the region above the light guide plate 102, and thus the stripe pattern It does not reach the observer's eyes and does not make the user feel uncomfortable due to the change in contrast.

As described above, in the present embodiment, light is applied to the stripe-shaped uneven shape 108 from the end side of the stripe-shaped uneven shape, and the light source 104 is a point light source. Since light emitted from the opposite direction was reduced and the light obliquely incident was used as illumination light, the light obliquely incident was guided to the end face 102S, and was diffusely reflected by the light diffusion plate 107. Light perpendicular to the concave-convex shape 108 can be excluded, and an annular or streak-like striped pattern due to light interference can be prevented from entering the eyes of the observer, and illumination with good contrast can be performed.

(Modification of Light Source 104) In the present embodiment, a plurality of point light sources are intermittently arranged along the end face 102L as the light source. However, as shown in FIG.
The light guide sheet 120 may be arranged along 02L, and the light source 104 may be arranged at one end of the light guide sheet 120. The light guide sheet 120 has a so-called cutting board surface facing the end face 102L side, and light incident on the end face of the light guide sheet 120 from the light source 104 is emitted to the end face 102L from the cutting board shape slope. Therefore, all light incident on the light guide plate 102 is oblique light, and the object and effects of the present embodiment can be achieved.

(Modification of Light Diffusion Plate 107) In this embodiment, the light diffusion plate 107 is attached only to the end face 102S. However, as shown in FIG. 6, the light diffusion plate 109 is attached to the end face 102L. May be attached. In FIG. 6, the light diffusion plates 109 are provided on both end surfaces 102L, but only one surface may be provided.

The light diffusing plate 109 may be either specular reflection or irregular reflection. However, regular reflection such as a mirror surface is preferable in consideration of unevenness in light amount. There is almost no light that is completely perpendicularly incident, and reciprocates between the end faces 102L.
This is because 2S is reached. Note that the two end surfaces 102L may not be parallel to each other, and one may be slightly inclined. Also,
The end face 102L may have an optical function so that all reflected light is deflected in the direction of the end face 102S.

Further, as shown in FIG. 7, the number of the light sources 104 is reduced, for example, the light source 102 is provided only on one end face 102L.
May be arranged. Further, the light source 104 is set to 1
It may be individual.

[0046]

As described above, the illuminating device and the light guide system according to the present invention have a configuration in which the reflected light of the light source is not emitted toward the observer, so that the contrast is good and the light quantity unevenness is prevented. It has an excellent effect that it can be produced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a lighting device according to an embodiment.

FIG. 2 is a plan view of the lighting device according to the present embodiment.

FIG. 3 is a side view of the light guide plate for explaining light guide in the light guide plate as viewed from the end face 102L side.

FIG. 4 is a front view seen from the end face 102S side of the light guide plate for explaining that light causing a stripe pattern is excluded from a viewing area.

FIG. 5 is a plan view of a lighting device showing a modification of the light source.

FIG. 6 is a plan view of a lighting device showing a first modification of the light diffusing plate.

FIG. 7 is a plan view of a lighting device showing a second modification of the light diffusing plate.

FIG. 8 is a perspective view of a conventional lighting device.

FIG. 9 is a side view of a concavo-convex shape for explaining inconvenience in a conventional lighting device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 lighting device 102 light guide plate 104 light source 107 light diffusion plate 108 uneven shape 109 light diffusion plate

Claims (6)

[Claims] 1. A light guide plate comprising a transparent thin and square plate material, provided with an uneven shape formed in a streak shape parallel to two sides facing each other in a contour of the plate material; A light source that is disposed on an end surface side corresponding to at least one end portion and emits light to be introduced into the light guide plate from the end surface; and is disposed corresponding to at least one of the end surfaces corresponding to the two sides of the light guide plate, A first light diffusing plate that prevents and reflects light in the light guide plate; 2. The lighting device according to claim 1, wherein the light source is a point light source disposed at one or a plurality of locations on the end face. 3. A light guide plate made of a transparent thin and square plate material, wherein the plate material has an uneven shape formed in a streak shape parallel to two sides facing each other, and at least one of the streaky uneven shape. A plurality of point light sources that are intermittently arranged on an end face side corresponding to one end and emit light to be introduced into the light guide plate from the end face, and an arrangement position of the point light source on an end face around the entire circumference of the light guide plate. A second light diffusing plate that is provided in a portion other than the light guide plate and that prevents and reflects light in the light guide plate. 4. A light guide system, comprising: a light source; and a light guide that emits light from the light source means toward a surface to be irradiated and guides reflected light from the surface to be irradiated to an observation side. A light guide system, wherein a reflector is provided for the light guide, and secondary light reflected by the reflector out of the light from the light source is emitted from the light guide toward the irradiated surface. 5. The light guide system according to claim 4, wherein the light source is a point light source, and the reflector functions to diffuse light from the point light source into the light guide. 6. The light guide comprises a linear projection, the point light source is provided at an end in a direction in which the linear projection extends, and the reflector emits light from the point light source. A light guide system configured to reflect toward a linear protrusion.