JPH02176692A - Light apparatus - Google Patents

Abstract

PURPOSE: To uniformly radiate light windows at an output side by positioning a structural surface having a plurality of prisms at the upper part in an optical cavity, deciding one surface at the top part, and allowing at least one part to make an acute angle against a collimation adjusted axial line. CONSTITUTION: An optical cavity constituted of wall parts 10 and 12 is provided with a light window provided with a light transmitting member 14 inside, and a partially collimation adjusted light source 16 is positioned adjacent to a side part 10 of a housing inside the optical cavity. A side part 22 of the wall part 12 is the surface of a structure having a plurality of preferably triangular prisms 24 at the upper part, and a light from the light source 16 is reflected to a prescribed direction. Then, a flat surface is decided at the top part of the prism 24, an acute angler θ is made against a collimation adjusted axial line 18, and a light beam emitted from the light source 16 is interrupted by the side part 22 of the wall part 12. Thus, the whole opening of the light window 14 can be uniformly irradiated.

Description

[Detailed description of the invention] 1. Kanjo 2. Takajiri Yodo” The present invention relates to thin optical devices.

Prior Art and Problems Thin optical devices are desirable under all circumstances. For example, backlit flat panel displays typically need to be kept as thin as possible.

The thinner they are, the lighter they weigh and the more compact they are, both of which are desirable properties when used in applications such as portable computers. Vehicle taillights and brake lights should also be kept compact if possible. The reason is that the space used by such lighting devices occupies luggage space in the trunk of a motor vehicle.

Various designs for thin light panels have been proposed. For example, US patent application Ser. No. 016,858, filed February 20, 1987, describes a Fresnel-type reflector located on a conical surface. Typically, the Fresnel-type structure of the reflector is designed to simulate parabolic characteristics. Although this conical Fresnel reflector provides a highly efficient and compact light source, it suffers from the same drawbacks as other parabolic reflectors. The disadvantage of this is that the light output intensity lacks uniformity. As expected, areas closer to the light source will be illuminated more brightly than areas further away from the light source.

Other designs are provided for use when uniform illumination is desired. One such proposal includes 198
U.S. Patent Joint Application No. 030.03 dated March 24, 2007
It is explained in No. 3. This design utilizes a film known as a right angle film. Using a right-angle film inside the light device can illuminate the output light window very uniformly, but it requires a separate structure called the right-angle film, which must be inserted into the light device. Must be. In certain cases, it would be desirable to create an optical device that has characteristics similar to those of devices using orthogonal films, without requiring the insertion of a separate film into the device.

SUMMARY OF THE INVENTION According to the invention, the housing defines an optical cavity having an optical window. A partially referenced light source having a reference axis is located within the optical cavity. Located within the optical cavity is a structured surface having a plurality of prisms thereon, the tops of the prisms defining a surface, at least a portion of which reflects light through the optical window. It forms an acute angle to the positive axis.

Embodiment FIG. 1 shows a first embodiment of the present invention. In the embodiment of FIG. 1, a wall io, 12 defines an optical gear. This optical cavity has a light transmission member 1 inside.
It has a light window with 4. The light transmitting member 14 may be made of transparent or translucent material. If desired, the light transmitting member 14 may comprise a structure such as a pillow optic or a Fresnel prism.

A partially referenced light source 16 is located inside the optical gear and adjacent the side 10 of the housing. The light source 16 may be any partially referenced light source, such as a fluorescent lamp or other gas discharge lamp with suitable reflectors, or an incandescent light with a reflector. Other light sources 16 may include a plurality of light emitting diodes (LEDs).

The side 22 of the wall 12 is a structured surface having a plurality of preferably triangular prisms 24 thereon. In a preferred embodiment, the prism 24 is a linear prism. The prisms 24 are mirror-reflective, typically by vapor coating aluminum. Prism 24 only needs to be mirror-reflective on the side closest to light source 16, but it is typically easier to vapor coat both sides. Such a prism reflects light from the light source 16 in a predetermined direction. Typically, the predetermined direction is perpendicular to the transparent or translucent material 14.

A light source 16 emits a generally referenced beam of light having a reference axis 18 . Line 20 is the reference alignment axis 1
It is drawn parallel to 8. As can be seen, the top of the prism 24 defines a flat surface, which corresponds to the lines 20,
That is, it forms an acute angle (θ) with respect to the reference alignment axis 18. As a result, the sides 22 of the wall 12 will block the light beam emitted by the light source 16. The structural surface 22 thus blocks the beam of light emitted by the light source 16, so that the entire opening of the light window is illuminated.

The structure of the present invention may be advantageously formed directly on the rear wall of the optical device. Such structures may be formed by injection molding. Alternatively, a separate film having a structured surface as described above may be placed in the optical device.

FIG. 2 shows an alternative embodiment to the embodiment of FIG. In the embodiment of FIG. 2, the structured surface 22' is curved. Therefore, the surface defined by the top of prism 24 is also curved rather than flat.

As a result, the surface is parallel or nearly parallel to the reference alignment axis in the region closest to the light source 16, but at various acute angles to said axis in regions further from the light source 16. ing. This has the effect that prisms further away from the light source 16 block a larger portion of the beam than prisms closer to the light source 16. The curves help ensure uniformity of illumination since the light beam naturally widens as it travels away from the light source.

FIG. 3 shows another embodiment, in which a wall portion 32,
A housing 30 consisting of 34, 36, and 38 defines an optical cavity with an optical window. A transparent or translucent cover 40 is placed over the light window. Light from two partially referenced light sources is transmitted to light source 42.4.
4, towards the structured surface 46.

The prismatic tops of the structured surfaces 46 may define a flat surface at an angle to the normal alignment axis of the light source, as in the embodiment of FIG. 1, or alternatively, as in the embodiment of FIG. Similarly, curved surfaces may be defined that block the light beam.

FIG. 4 shows another embodiment of the invention, in which the light source 14' has a light emitting portion 50 and a structured surface 52. Structured surface 52 acts similarly to structure surface 22, receiving light from compact light source 50 and providing a straight beam. The embodiment of FIG. 4 then operates similarly to the embodiment of FIG. 1, with surface 52 acting as a light source for structure surface 24.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a first embodiment of an optical device according to the present invention, FIG. 2 is a diagram of a second embodiment of an optical device according to the present invention, and FIG.
The figure is a diagram of a third embodiment of the optical device according to the invention having two light sources, and FIG. 4 is a diagram of a fourth embodiment of the optical device according to the invention. In the figure, 14... optical window, light transmission member, 16... light emitting device, 18... standard adjustment axis, 22... inner surface, 24... prism.

Claims (6)

[Claims] (1) an optical device, comprising: a housing defining an optical cavity having an optical window and having an inner surface opposite the optical window; and emitting a partially referenced light beam having a reference axis; a light emitting device in the housing for transporting light, a plurality of prisms on the inner surface, each of the prisms directing light from the light emitting device through the light window and out of the optical cavity. for reflection, having a mirror-reflective surface on the side closer to the light emitting device, the top of the prism defining a surface, at least a portion of the surface An optical device characterized in that it forms an acute angle with respect to a reference alignment axis. 2. The optical device of claim 1, wherein the surface defined by the apex is smoothly curved. (3) The optical device according to claim 1, further comprising a light transmission member within the optical window. (4) An optical device according to claim 3, wherein the prism reflects the light from the light emitting device in a direction substantially perpendicular to the light transmitting member. 5. The apparatus of claim 4, wherein each of said specularly reflective surfaces is approximately 45.degree.
A light device that forms an angle equal to degrees. (6) The optical device according to claim 1, wherein the prism is a linear prism.