JPH10288967A - Panel illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel illumination device which is constituted so that light emitting diodes are efficiently used and a uniform irradiating action without unevenness is executed and which is free from maintenance. SOLUTION: This device 20 is constituted so that the light emitting diodes 3 disposed on the inside of a rectangular housing are used as a light source and a plastic panel is stuck to the front surface side of the housing. Then, the diodes 3 are arrayed along the opposed inside surfaces 2A and 2B of the housing so as to face each other by almost horizontally adjusting the directions thereof. Besides, a reflection paper 4 shaped like a gable roof and folded into two with the almost central line position of the housing dividing the housing to the opposed inside surfaces 2A and 2B as a ridgeline 6 is disposed at the inside bottom surface of the housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a panel lighting device used for an advertisement display, a road information display, and the like, and more particularly, to an irradiation structure of a panel lighting device using a light emitting diode (LED) as a light source.

[0002]

2. Description of the Related Art Conventionally, as an advertising display or a road information display, a panel lighting device of a system in which a plastic panel surface on which characters and the like are printed is illuminated with a light source of an incandescent light bulb or a fluorescent light arranged on the back side to make it stand out. 2. Description of the Related Art A so-called electronic display panel is used in which a large number of light sources, such as LEDs, which are densely arranged in a matrix, are controlled by a computer to blink and blink characters and the like on the light source itself.

At present, the above-mentioned light-emitting display panel requires a complicated control circuit and a large number of light sources, so that it is expensive as an information display lighting device, and its use is limited.

On the other hand, when only one piece of information is to be warned and provided, for example, road information such as "under construction" or "decreased lanes" is sufficient with an ordinary relatively inexpensive panel lighting device.

FIG. 4 is an internal plan view of the above-mentioned conventional panel lighting device with a plastic panel removed.
As can be seen from the figure, an inexpensive fluorescent lamp is mainly used as a light source in the panel lighting device 40 from the viewpoint of cost, and several fluorescent lamps (straight tubes) 21 are arranged inside the rectangular housing 1 to form a ballast. Etc., and a translucent (white or red color is common) plastic panel 15 on the front side of which is printed character information such as "under road construction" with black or red paint.
It is a simple structure with affixed.

[0006]

However, in the above-mentioned conventional panel lighting device, firstly, the life of the fluorescent lamp is usually several thousand hours, and although it is longer than the incandescent lamp, it is limited, so that the replacement is not possible. Inevitable and requires maintenance.

Second, a panel lighting device as a road information display needs to be robust and has sufficient durability (high physical strength) in handling since it is repeatedly transported, installed and removed, but the fluorescent lamp is broken. There is a problem that when transported to the site, the fluorescent lamp is already broken and cannot be used frequently.

In this respect, there is a light emitting diode (LED) having a semi-permanent life and excellent physical strength as a light source of a panel lighting device instead of a fluorescent lamp.
In order to irradiate the entire wide plastic panel because the light emitting portion is small and the irradiation angle is small, for example, an internal plan view of the panel illuminating device 50 of FIG. 5 and FIG.
As shown in (2), it is necessary to arrange a large number of light emitting diodes 3 in a matrix on a substrate 24 arranged near the inner bottom surface of the rectangular housing 1.

The occurrence of uneven brightness on the irradiated surface (plastic panel) is a fatal defect as a panel lighting device. However, as can be seen from the cross-sectional view of FIG. 6, the entire irradiated surface of the plastic panel 15 is not uneven. To irradiate the light uniformly with the light emitting diode 3, it is necessary to keep the distance H between the plastic panel 15 and the light emitting diode 3 to some extent. For example, the dashed-dotted plastic panel 15 'in FIG.
When the distance from the light emitting diode 3 is set to be short like H1, the dark area D and the bright area S are formed, and unevenness occurs as a whole. Plastic panel 1 to avoid this
When the distance from the light emitting diode 3 is set to H2 as shown in FIG. 5, the dark area D is eliminated and an almost uniform irradiation surface is obtained, but as a result, the thickness of the panel illuminating device 50 increases and becomes large. I will.

[0010] Further, although the light emitting diode 3 is inexpensive as compared with the conventional one, if a large number of light emitting diodes 3 are used, there is a problem in cost. Therefore, at present, panel lighting devices using light emitting diodes as light sources can be applied only to small ones.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a maintenance work that can efficiently arrange a small number of light emitting diodes inside a housing to give uniform irradiation without unevenness to a panel and make the apparatus itself thin. It is intended to provide a free panel lighting device.

[0012]

According to the present invention, there is provided a panel lighting device having a structure in which a plastic panel is attached to a front surface of a housing using a light emitting diode disposed inside a rectangular housing as a light source. In the device, the light emitting diodes are arranged along the opposing inner surface of the housing so as to be substantially horizontal to the plastic panel surface so as to face each other, and the opposing inner surface is divided and the substantially center line position of the housing is set. Provided is a panel lighting device characterized in that a gable roof-shaped reflecting paper folded in half as a ridge is disposed on an inner bottom surface of a housing.

(2) In a panel lighting apparatus having a structure in which a plastic panel is attached to the front side of a housing using a light emitting diode disposed inside a substantially cylindrical housing as a light source, light is emitted along the periphery of the inner surface of the housing. The diodes are arranged annularly so as to be substantially horizontal to the plastic panel surface and the light emission direction is directed toward the center of the housing, and a conical reflective paper having a vertex at the center axis of the housing is provided on the inner bottom surface of the housing. Provided is a panel lighting device characterized by being provided.

(3) The slope of the gable-roof-shaped reflecting paper or the conical-shaped reflecting paper which is folded in half has a shape which is steeply upward and gently curved downward. Alternatively, a panel lighting device according to claim 2 is provided.

The reflection paper is a white or nearly white color having a high reflection efficiency, and is made of plain paper, Kent paper, plastic synthetic paper, or the like. Paper that is flat and suitable for diffuse reflection (normal paper has such properties).

[0016]

Embodiments of the present invention will be described with reference to the drawings. The same members as those in the conventional example are designated by the same reference numerals.

FIG. 1 is an internal plan view showing an arrangement state of light emitting diodes of a panel lighting device according to a first embodiment of the present invention with a plastic panel removed.

FIG. 2 is an enlarged view of a cross section taken along line AA of the panel lighting device.

FIG. 3 is an internal plan view and a sectional view showing an arrangement state of the light emitting diodes of the panel lighting device according to the second aspect of the present invention with the plastic panel removed.

In FIG. 1, a panel lighting device 20 has a structure in which a light emitting diode 3 disposed inside a rectangular housing 1 is used as a light source and a plastic panel 15 similar to that of FIG. The light-emitting diodes 3 are arranged along the opposing inner surfaces 2A and 2B of the housing 1 so as to be substantially horizontally aligned with the surface of the plastic panel 15 so as to face each other. A gable-roof-shaped reflecting paper 4 which is divided into 2B and is roughly folded in two with the substantially centerline position of the housing 1 as a ridgeline 6 is provided on the inner bottom surface of the housing 1.

The gable-roof-shaped reflecting paper 4 folded in half has a slope 7 which is flat (straight in the cross-sectional view) or has a shape which is sharply curved upward and sharply downward as shown in FIG. (As if it were a stratified volcano like the end of Mt. Fuji).

The distance between the light emitting diodes 3 is approximately 30 to 40 m.
It is mounted substantially horizontally with respect to the plastic panel 15 so as to be positioned at half the height (about 30 mm) of the reflective paper 4 with m, but the angle of the light beam may be adjusted slightly in the vertical direction. Will. Reference numeral 19 denotes a power supply circuit of the light emitting diode.

The overall dimensions of the panel lighting device 20 are 30 cm in length, 60 cm in width, and 4.5 cm in thickness in the embodiment of FIG.
About.

From the above structure, as shown in FIG. 2, the light beam from the light emitting diode 3 is incident on the reflection paper 4 at a shallow angle of inclination, and thus directly hits a wide elliptical area.

Further, since the reflecting paper 4 is not a smooth mirror surface but a rough surface having fine irregularities, the irradiated light beam (light flux) is irregularly reflected by the irregularities on the surface of the reflecting paper 4 and spreads at a wide angle. The light is reflected toward the plastic panel (FIG. 2).

As a result, a backlight without unevenness is obtained in which the plastic panel surface is almost uniformly illuminated from the back side by the light emitting diodes and the light flux of each light emitting diode is not felt. Moreover, the thickness of the device can be reduced as described above.

The reflection paper 4 is made of white or close to white with high reflection efficiency, and is made of plain paper, Kent paper, plastic synthetic paper, or the like, and has a fine uneven surface and is suitable for irregular reflection. Paper (normal paper has the property and is inexpensive).

As described above, the present invention is characterized by a thorough indirect lighting configuration in which the light emitting diodes are radiated on the reflecting paper which is gently inclined toward the panel substantially gently and scattered to irradiate the panel. This can be applied to devices other than the above-described device having a rectangular housing.

For example, FIG. 3 shows a panel lighting device 30 having a structure in which a light emitting diode 3 disposed inside a substantially cylindrical housing 31 as a light source and a plastic panel 15 is attached to the front side of the housing 31. The light emitting diodes 3 are arranged annularly along the periphery of the inner surface of the housing 31 substantially horizontally with respect to the surface of the plastic panel 15 so that the light emitting direction (luminous flux) is directed toward the center of the housing.
This is a configuration in which a conical reflective paper 34 having an apex at 3 is disposed on the inner bottom surface of the housing.

In the panel illuminating device 30 as well, a wide, substantially elliptical direct illuminating surface A 'is formed on the reflecting paper 34 similarly to the above-described example.
Appear on the plastic panel 15
It can be said that the effect of illuminating is obtained.

The inclined surface of the gable-roof-shaped reflecting paper 4 or the conical-shaped reflecting paper 34 which is folded in half is shaped such that it is steeply curved upward and gently downward as shown in FIGS. In the case of the above, it was found from the test of the present inventor that the irregular reflection with the reflection paper was most efficiently irradiated uniformly on the plastic panel surface.

It should be noted that the standard of the light emitting diode 3 used in the present invention is not limited, and various colors can be applied. If the plastic panel 15 is made detachable, various information displays can be appropriately selected and used in one panel lighting device. The shape of the housing is typically rectangular or circular as described above, but some modifications are included in the scope of the present invention.

[0033]

The panel lighting apparatus using the light emitting diodes as the light source according to the present invention is configured as described above. (1) Despite the small number of light emitting diodes used and low cost, unevenness in the panel An excellent effect of realizing no uniform illumination is achieved.

(2) There is an excellent effect that the apparatus itself can be made thin.

(3) An excellent effect that the physical strength of the device is high and maintenance-free is achieved.

[Brief description of the drawings]

FIG. 1 is an internal plan view showing an arrangement state of light emitting diodes of a panel lighting device according to claim 1 of the present invention with a plastic panel removed.

FIG. 2 is an enlarged view of a cross section taken along line AA of FIG. 1 of the panel lighting device.

FIGS. 3A and 3B are an internal plan view and a sectional view, respectively, showing an arrangement state of a light emitting diode in a state where a plastic panel is removed from a panel lighting device according to a second embodiment of the present invention.

FIG. 4 is an internal plan view of the conventional panel lighting device with a plastic panel removed.

FIG. 5 is an internal plan view of a conventional panel lighting device using light emitting diodes.

FIG. 6 is a sectional view showing an enlarged vertical section inside the panel lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectangular housing 2A, 2B Inner surface 3 Light emitting diode (LED) 4, 34 Reflective paper 6 Ridge 7 Slope 11 Electric circuit board 12 Member A, A 'Irradiation area 15, 15' Plastic panel 19 Power supply circuit 20, 30, 40 , 50 Panel lighting device 24 Substrate 31 Cylindrical housing 33 Central axis

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Takashi Akuzawa 25-1, Oma Oyama, Yamada-gun, Gunma Prefecture

Claims (3)

[Claims] 1. A panel lighting device having a structure in which a plastic panel is attached to a front surface of a housing using a light emitting diode disposed inside a rectangular housing as a light source, wherein the light emitting diode is disposed along a facing inner surface of the housing. A gable-roof-shaped reflecting paper which is arranged substantially in a horizontal direction with respect to the surface and is faced to each other, and which is divided into two by dividing the opposing inner side surface and substantially at the center line position of the housing as a ridge line, is provided inside the housing. A panel lighting device characterized by being disposed on a bottom surface. 2. A panel lighting apparatus having a structure in which a plastic panel is attached to a front surface of a housing using a light emitting diode disposed inside a substantially cylindrical housing as a light source, and the light emitting diode is formed along a periphery of an inner side surface of the housing. A conical reflector having a vertex on the central axis of the housing is disposed on the inner bottom surface of the housing, and is arranged in a ring shape so that the light emitting direction is substantially horizontal to the panel surface and the light emission direction is directed to the center side of the housing. A panel lighting device, comprising: 3. The reflection paper having a gabled roof shape or the conical reflection paper which is folded in half has a shape in which an upper portion is steeply curved upward and a lower portion is gradually curved. The panel lighting device according to claim 2.