JP5858330B2 - Display device - Google Patents

Description

  The present invention relates to a display device using a highly directional point light source, and more specifically, a display device capable of obtaining uniform illumination light by irradiating a plurality of different directions with the same point light source or group of point light sources. About.

  In recent years, research and development of LEDs have progressed rapidly, and various types of LEDs have been developed and commercialized and used in a wide range of fields. LEDs have been conventionally used as operation indicator lamps for electronic devices because of their low power consumption, long life, and small size. These LEDs are often used, for example, in backlights for liquid crystal panels, various display boards, electric bulletin boards, and electrical decoration devices.

  However, since the LED has a strong directivity of light, the LED alone is difficult to use as illumination. Therefore, various devices have been devised to use the LED for illumination. For example, as a conventional surface illumination light source device that uses a LED as a light source to obtain illumination light having a planar and uniform illuminance distribution, a light transmitting resin is provided on the light emission surface to diffuse the light. There are known ones in which a reflecting means is provided on the light emitting surface and light is subjected to multiple reflection (see Patent Document 1 below).

  That is, as shown in FIG. 9, the surface illumination light source device 50 described in Patent Document 1 includes a point light source 51 with strong directivity such as an LED, a bottom surface 52 and a side surface 53 with a predetermined area, and an opening 54. The casing 55 is provided with a casing 55 provided with inner and side reflecting portions for reflecting and irregularly reflecting light on the inner wall surface, and radiation-side reflecting means 56 for covering, opening, reflecting, and irregularly reflecting the light. A point light source 51 is disposed in the central portion of 52, and the radiation side reflection means 56 includes a central reflection portion 57 within a predetermined range directly above the point light source 51 and an outward reflection portion 58 around the outer periphery of the central reflection portion 57. The outer reflecting portion 58 is made of a reflecting member that partially transmits, reflects, and irregularly reflects light and has a predetermined reflectance, and the central reflecting portion 57 has a reflectance higher than the reflectance of the outer reflecting portion 58. Formed with a light transmissive reflective part To have.

  The surface illumination light source device 50 multi-reflects light having a high directivity emitted from the LED between the radiation-side reflecting means 56 having the central reflecting portion 57 and the outer reflecting portion 58 and the inner surface of the casing 55, Transmitted light with uniform light intensity can be emitted from the radiation side reflection means 56.

  In addition, as in the invention described in Patent Document 2 below, a technology of a surface light source device that uses a plurality of point light sources to eliminate luminance unevenness of illumination light is also disclosed.

  That is, the surface light source device 60 described in Patent Document 2 below is a light source provided on a plurality of substrates 62 in a state where the LEDs 61 as point light sources are spaced apart, as shown in FIG. A reflective member 63 such as a silver tape is provided so as to face an end face portion to be described later. Reference numeral 64 denotes a light guide plate made of a translucent material. An incident surface on which light from a light source is incident, an exit surface 65 from which the incident light is emitted while passing through the light guide plate, and a surface facing the exit surface 65. A certain back surface is provided, and the thickness of the light guide plate 64, that is, the distance between the exit surface 65 and the back surface is formed smaller as the distance from the entrance surface increases. This shape improves the output efficiency of the emitted light. Although not shown, a diffusion pattern may be formed on the back surface as diffusion means that is designed so that incident light is emitted from the emission surface 65 with uniform luminance.

Japanese Patent No. 4280283 JP 2001-014922 A

  According to the surface illumination light source device disclosed in Patent Document 1 above, even if a highly directional point light source such as one LED is used, it is uniform over a wide area without increasing the thickness in the radial direction of the LED. An excellent effect that it is possible to obtain a proper illumination light. However, in the surface illumination light source device disclosed in Patent Document 1, it is difficult to uniformly illuminate the whole when the distance from the point light source is too different, for example, a triangular prism shape or a star column shape. there were.

  In addition, when a plurality of point light sources are used as in the surface light source device disclosed in Patent Document 2, even if a problem occurs in only one of the point light sources being used, uneven brightness occurs. As a result, there has been a problem that work for replacing the point light source frequently occurs.

  The present invention has been completed in order to solve the above-described problems of the prior art, and a uniform illumination light can be obtained by irradiating a plurality of different directions with the same point light source or group of point light sources. It is an object to provide a display device that can be used.

Viewing device of the present invention includes a point light source is a light emitting diode, a substrate on which the point light source is attached, has the substrate at the center, and the bottom plate with a hole for mounting the point light source is provided, A casing having a side plate portion erected vertically from each end of the bottom plate portion at a predetermined height and having a surface facing the bottom plate portion opened, and a light conducting reflection attached to the opening of the casing. A housing that accommodates the plate, the casing, and includes a bottom surface and a side surface that is erected vertically from each end of the bottom surface by a predetermined length; and a surface that faces the bottom surface is opened. And a display plate that is attached so as to cover the entire opening of the housing and transmits light. The light conducting reflection plate has a higher light transmittance as the distance from the point light source increases. Also, the light reflectance is low A light direction adjusting plate that reflects light and is installed between the point light source and the light conducting reflector so as to stand from the bottom plate and cover the point light source. the light direction control plate, the light direction adjusting holes around the other optical axis of the point light source that has been opened at least one.

According to Viewing device of the present invention, it is used a strong point light source directivity as light emitting diodes, the light reflectance of the portion facing the point light source of the light conducting reflection plate has the highest and the light transmittance is the lowest Since the light transmittance increases and the light reflectance decreases with increasing distance from the point light source, uniform illumination light can be obtained from the entire surface of the light conducting reflector. In addition, it is possible to provide a display device that can irradiate a plurality of different directions with the same point light source or point light source group to obtain uniform illumination light.

Further, the display device of the present invention further, the shape of the bottom plate portion and the bottom portion is Ru regular polygon der a similar to each other.

According to Viewing device of the present invention, light from a point light source becomes uniform in the casing, can be irradiated to the entire without waste uniform display board, it is possible to obtain a more uniform illumination light.

Viewing apparatus further, the light direction adjusting holes of the present invention is equal to the number of vertices of the bottom plate portion, the light direction adjusting holes that have been drilled toward the apex direction of the bottom plate portion.

According to Viewing device of the present invention, it is possible to distance from the point light source to each vertex of the farthest comprising a bottom plate section, it can be efficiently irradiated with light, to obtain a more uniform illumination light.

In Viewing device of the present invention, the shape of the light direction control plate can be a positive polygonal pyramid having one vertex on the optical axis of the point light source.

In such a case , by using a regular polygonal pyramid, the distance between the light direction adjusting plate as a reflector and the point light source can be increased on the optical axis where the light from the point light source is the strongest. . When the distance between the point light source and the reflector is too short, retroreflected light to the point light source is generated by the reflector, the light loss increases, and the quality of the display device is degraded. Further, by using a polygonal pyramid, the light in the optical axis direction of the point light source and the reflector do not intersect perpendicularly, and the generation of recurring light to the point light source can be suppressed.

Further, in the Viewing device of the present invention, the plan view shape of the light conducting reflection plate may be similar in shape to the bottom plate portion.

In such a case , the direction of the light can be easily set, and the manufacture becomes easy.

Further, in the Viewing device of the present invention, members of the casing may be ultra-fine foamed light reflecting member.

In such a case , the light irradiated from the point light source is lost by using an ultrafine foamed light reflecting member having a high light reflectance and a low light transmittance as a member for forming the casing and the light conducting reflector. And can be used with high efficiency.

FIG. 1 is an external perspective view of a display device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the display device according to the embodiment of the present invention. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a plan view of a photoconductive reflector used in the display device of this embodiment. 5A is a perspective view of a light direction adjusting plate attached to the display device of the present embodiment, FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A, and FIG. 5C is a development view of the light direction adjusting plate. FIG. 6 shows another example of the light direction adjusting plate. 7A and 7B are external views of the display device according to each modification of the present invention, and FIGS. 7C and 7D are plan views of the light conducting reflection plate according to each modification of the present invention. It is a perspective view of the light direction adjustment board in each modification of the present invention. It is a sectional side view of the surface illumination light source device currently disclosed by patent document 1. FIG. It is a top view of the surface light source device currently disclosed by patent document 2. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a display device for embodying the technical idea of the present invention, and is not intended to specify the present invention. It is equally applicable to the other embodiments included.

[Embodiment]
First, with reference to FIGS. 1-4, the display apparatus in embodiment of this invention is demonstrated. 1 is an external perspective view of the display device according to the embodiment of the present invention, FIG. 2 is an exploded perspective view of the display device according to the embodiment of the present invention, FIG. 3 is a sectional view taken along line III-III in FIG. These are the top views of the photoconductive reflection plate used for the display apparatus of this embodiment.

  The display device 10 includes an equilateral triangular bottom surface portion 11a having a side length of about 800 mm, and side surface portions 11b, 11c having a height of 20 mm that are vertically erected from each side of the bottom surface portion 11a. 11d, a housing 11 having an opening 11e formed on a surface facing the bottom surface portion 11a, and a display plate 15 attached so as to close the opening 11e of the housing 11.

  Inside the housing 11, there is an equilateral triangular bottom plate portion 13a having a side length of about 795mm, and a side plate portion 13b having a height of 17mm that is erected vertically from each side of the bottom plate portion 13a. A casing 13 in which an opening 13e is formed is attached to the surfaces facing 13c and 13d and the bottom plate portion 13a.

The on center-of-gravity point of the bottom plate portion 13a has holes 3 ₀ are opened, the point light source 15 is inserted. The point light source 15 is fixed to a substrate (not shown) fixed to the casing 13 and further connected to an external power source or the like. In this embodiment, the point light source 15 is a white diode having one light emitting element or a plurality of light emitting elements.

The casing 13 is made of a material having a high light reflectance, for example, a material such as an ultrafine foamed light reflecting plate having characteristics of a light reflectance of 98%, a light transmittance of 1%, and a light absorption of 1%. Since the light from the point light source 15 can be reflected at a high light reflectance on the inner wall surface 13, it can be used efficiently. Further, since the ultrafine foamed light reflecting plate is lightweight, the weight of the display device 10 can be suppressed. Furthermore, since the ultrafine foamed light reflecting plate is easily available and relatively inexpensive, the cost can be reduced even when the display device 10 is manufactured.

A regular hexagonal light conducting reflection plate 14 centered on the optical axis of the point light source 15 and supported by the side plate portions 13b to 13d is attached to the opening 13e. A claw portion 13f is provided on each of the upper portions of the side plate portions 13b to 13d. By passing the claw portion 13f through a locking hole 14f provided in the light conduction reflection plate 14, the light conduction reflection plate 14 and the casing are provided. 13 is engaged. By engaging with the claw portion 13f and the locking hole 14f, the light conducting reflection plate 14 can be easily attached and detached.
A light direction adjusting plate 16 is provided on the optical axis of the point light source 15 and between the point light source 15 and the light conducting reflection plate 14. The light direction adjusting plate 16 will be described later.

  The light conducting reflection plate 14 has a predetermined thickness and is formed of a material such as an ultrafine foamed light reflecting member having a high light reflectance and a low light transmittance. In this embodiment, the thickness is 1 mm. Thereby, the light from the point light source 15 can be reflected with high light reflectivity and used efficiently. Further, since the ultrafine foamed light reflecting member is easily available and relatively inexpensive, the manufacturing cost can be suppressed. As shown in FIG. 3, the photoconductive reflector 14 has a central photoconductive reflector 14a and an outer periphery of the central photoconductive reflector 14a within a predetermined distance centered on the center of gravity of the photoconductive reflector 14. An outward light conducting reflection portion 14b is provided.

  A central portion 14 a 1 is provided on the central portion of the central light conducting / reflecting portion 14 a, that is, on the optical axis of the point light source 15. The central portion 14a1 is formed with a high light reflectance, reflects strong light emitted from the point light source 15, and the reflected light is multiple-reflected by the side plate portions 13b to 13d, the bottom plate portion 13a, and the light conducting reflection plate 14. It is like that. The light reflectivity of the central portion 14a1 is appropriately set by selecting an optical reflecting plate material and processing the material (eg, forming a half groove, adjusting the plate thickness) so that light can be used efficiently. become.

  A peripheral portion 14a2 is provided at the periphery of the central portion 14a1 and at the boundary between the outer light conducting and reflecting portion 14b. The peripheral portion 14a2 is provided with a small-diameter fan-shaped hole, and is designed to transmit a part of light while increasing the light reflectance next to the central portion 14a1. Further, by making the diameter small, the light emitted from the point light source while having a predetermined light transmittance is not directly conducted through the light conducting reflector. The small-diameter hole may be changed to a narrow groove.

  Circular openings 14b1 are formed at predetermined intervals in the outward light conducting reflection portion 14b. The hole diameter of the opening 14b1 gradually increases as the distance from the central light conducting reflection portion 14a increases. The narrow grooves and openings 14b1 are designed to conduct light emitted from the point light source 15 and reflected one or more times by the side plate portions 13b to 13d, the bottom plate portion 13a, and the light conducting reflection plate 14. Instead of the circular opening, a concentric annular or rectangular slit may be provided, and the width may be increased as the distance from the central light conducting reflection portion 14a increases. By arranging the photoconductive reflector 14 having the above-described configuration so as to face the point light source 15, it is possible to obtain illumination light having a uniform illuminance distribution even when an LED having a strong directivity of light is used as the light source. it can.

  Next, the light direction adjustment plate attached to the display device will be described with reference to FIGS. 5A is a perspective view of the light direction adjusting plate attached to the display device of this embodiment, FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A, FIG. 5C is a development view of the light direction adjusting plate, and FIG. Is another example of the light direction adjusting plate.

  The light direction adjusting plate 16 is a symmetrical figure with the optical axis of the point light source 15 as the axis of symmetry. In this embodiment, the light direction adjusting plate 16 has a regular triangular pyramid shape including three surfaces 16a, 16b, and 16c erected from the bottom plate portion 13a of the casing 13, and one surface of the bottom plate portion 13a. The length of one side of each surface is about 10 mm. The vertex that is not in contact with the bottom plate portion 13a of the light direction adjusting plate 16 is on the optical axis of the point light source. On each surface 16a to 16c of the light direction adjusting plate 16, light direction adjusting holes 17a to 17c are provided at the center of each side in contact with the bottom plate portion 13a. The size and shape of the light direction adjusting holes 17a to 17c are equilateral triangles having a side of about 3 mm. Each light direction adjustment hole 17a-17c is provided on the line segment which connected 13a 'which is each vertex of the point light source 15 and the baseplate part 13a of a casing.

  As shown in FIG. 6, the position of the light direction adjusting hole 17 may be provided around the midpoint of each side extending from the vertex passing through the optical axis of the point light source 15 in the light direction adjusting plate 16. Further, the shape of the hole does not need to be a regular triangle, and may be a rhombus shape, a circular shape or a porous shape, although not shown, as shown in FIG.

The light from the point light source 15 is reflected at the apex portion of the light direction adjusting plate 16 and is irradiated from the light direction adjusting holes 17 provided in the surfaces 16a to 16c, so that it is on the optical axis of the point light source 15. And the entire display panel 12 can be illuminated uniformly.
[Modification]

In the above embodiment, the shape of the display device is a regular triangular prism shape, the shape of the light conducting reflection plate is a regular hexagonal shape, and the shape of the light direction adjusting plate is a regular triangular pyramid shape.
As shown in FIG. 7, the display device 10B has an elliptical columnar shape or a display device 10C having a star-shaped column shape, or a photoconductive reflector according to the shape of the display devices 10B and 10C. Alternatively, the light conducting reflection plate 14B having an elliptical shape or the light conducting reflection plate 14C having a pentagonal shape may be used.
Also, the light direction adjusting plate is not a regular triangular pyramid shape, but may be a roof type shape, a hemispherical shape, a pentagonal pyramid shape or the like as shown in FIG.

DESCRIPTION OF SYMBOLS 10 ... Display apparatus 11 ... Housing 11a ... Bottom surface part 11b, 11c, 11d ... Side surface part 12 ... Display board 13 ... Casing 13 ₀ ... Hole 13a ... Bottom plate part 13b, 13c, 13d ... Side plate part 13e ... Opening 14 ... Light conduction reflection Plate 15 ... Point light source 16 ... Light direction adjusting plate 17 ... Light direction adjusting hole

Claims (4)

A point light source that is a light emitting diode ;
A substrate on which the point light source is attached;
The base plate having the substrate in the center and provided with a hole for attaching the point light source, and the side plate vertically provided at a predetermined height from each end of the bottom plate part, A casing having an open surface facing the bottom plate,
A light conducting reflector attached to the opening of the casing;
A housing that houses the casing, has a bottom surface and a side surface that is vertically erected from each end of the bottom surface by a predetermined length, and has a surface that faces the bottom surface;
A display board attached to cover the entire opening of the housing and transmitting light;
In a display device having
The light conducting reflector is formed such that the light transmittance increases as the distance from the point light source increases, and the light reflectance decreases,
Between the point light source and the light conducting reflection plate, a light direction adjusting plate that reflects light and is erected from the bottom plate portion and attached to cover the point light source,
The light direction adjusting plate has at least one light direction adjusting hole with a center other than the optical axis of the point light source ,
The shapes of the bottom plate part and the bottom part are regular polygons similar to each other,
The light direction adjusting hole is equal to the number of vertices of the bottom plate portion, and the light direction adjusting hole is opened toward the vertex direction of the bottom plate portion .   The display device according to claim 1, wherein the shape of the light direction adjusting plate is a regular polygonal pyramid having one vertex on the optical axis of the point light source.   The display device according to claim 1, wherein a shape of the light conducting reflection plate in plan view is similar to that of the bottom plate portion.   The display device according to claim 1, wherein the casing member is an ultrafine foamed light reflecting member.

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