JPH047506A - illuminated panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention causes light incident on an optical fiber from a light source to be emitted in a planar manner from the side surface of an optical fiber sheet, and from the back surface of a translucent display board, liquid crystal, etc. The present invention relates to a lighting panel that can emit light.

[Prior Art] An optical fiber with a core-sheath structure transmits light traveling inside the core by total reflection. Due to scratches such as notches that break through part of the sheath layer and reach the core of the optical fiber,
Forming a light leakage part and assembling a lighting panel by leaking light from this light leakage part is described, for example, in Japanese Patent Publication No. 46-42534.
This method is known from Japanese Utility Model Publication No. 53-24750.

In the above-mentioned conventional technology, the light leaking from the light leaking portion has the disadvantage that the light becomes darker as the distance from the light source increases, making the brightness of the display panel non-uniform.

On the other hand, as a technology to eliminate the above-mentioned non-uniformity,
For example, Japanese Patent Publication No. 61-24684 and Japanese Patent Publication No. 61-24684
-24685 has been proposed. This conventional technology attempts to obtain uniformity in brightness by controlling the density of multiple flaws that form light leakage areas so that they are represented by a certain function along the longitudinal direction of the optical fiber. be.

That is, when the irradiation start position of the optical fiber is rO1 constant is C, if the flaw density n formed at each position r of the optical fiber is controlled to be C, e-fr-ro), brightness can be achieved in the longitudinal direction. It is assumed that uniformity of the thickness can be obtained. FIG. 7 schematically shows the formation of a light leakage portion of an optical fiber and the relationship between the flaw density (n) and the distance from the light source side end.

Normally, as an effective means of forming light leakage areas in optical fiber sheets, in practice, emery paper is placed on top of the optical fiber sheet and a heating plate is pressed onto it, using the effects of heating and pressure. There is a hot stamping method in which fine particles fixed on the emery paper surface are press-fitted into the sheath layer of an optical fiber to break the sheath layer.

When forming a light leaking part using this hot stamping method, it is possible to change the density of scratches in the light leaking part along the longitudinal direction of the optical fiber by, for example, placing a rubber cushion sheet under the optical fiber sheet, and This can be achieved by partially controlling the pressing force when the heating plate is pressed against the heating plate by changing the thickness of the heating plate as necessary.

[Problems to be Solved by the Invention] However, according to the hot stamping method, although it is possible to change the density of scratches formed in the light leakage area,
Controlling as shown in the prior art functions described above requires that the thickness of the cushion sheet be varied approximately accordingly. However, in reality, the necessary thickness control range is on the order of several hundred microns, and it is not easy to control the thickness of the cushion sheet to match the above function at such a level, and it is difficult to is virtually impossible to implement.

Even if it were possible to achieve this, if a light source is used to inject light into the optical fiber sheet with the resulting light leakage part,
The way light spreads (light intensity distribution, output angle distribution, etc.) differs depending on the type of light source, and simply controlling the density of scratches is not enough to control the light leakage probability and amount of light leakage at each location and reduce the amount of afterglow to zero. It's not easy to get close.

If an attempt is made to damage an optical fiber sheet in which optical fibers are arranged in a sheet shape using a hot stamping method or the like, it is virtually impossible to form light leakage portions in the pattern shown in FIG. 7 shown in the prior art. That is, in FIG. 7, the light leakage portion is shown as being formed over the entire width of the optical fiber in a plan view, and appears to exist over approximately 1/2 the circumference of the optical fiber. However, in reality, the light leakage portion formed when a plurality of optical fibers are arranged in a sheet shape is 1/1 as shown in FIG.
It is not possible to form a leakage area over two circumferences, and it is reduced to a fraction of that, resulting in a considerable reduction in the leakage probability and hence the flaw density as specified in the prior art. If only the control is performed, the probability of light leakage and the amount of light leakage cannot be sufficiently controlled, and a high-performance lighting panel with a low amount of afterglow and a high light utilization rate cannot be realized.

Furthermore, the sandblasting method, which is relatively commonly used as another light leakage component composition technique, is a method in which fine particles such as sand or glass beads are jetted from a nozzle and hit the object.
Although it is possible to form a light leakage area close to 1/2 of the circumference of the optical fiber, due to the characteristics of this sandblasting method, it is not possible to simply spray fine particles as n = (C, e-(r-rob
) It is difficult to control the flaw density to a function of −1, and the density must be constant over almost the entire area.

Furthermore, it is practically difficult to obtain a conventional lighting panel having a controlled light leakage portion by press-fitting a protrusion such as a needle into an optical fiber.

This invention was made based on the above background,
The purpose is to provide an illumination panel that can uniformly illuminate the entire illumination surface, can utilize the light energy traveling in the optical fiber with high efficiency, and can be industrially manufactured easily.

[Means for Solving the Problem] In order to solve the above problem, the present inventors conducted various design studies and found that, in addition to the density of flaws in the light leakage part, the light leakage width and the flaw width were The present inventors have found that it is effective to achieve the object of the present invention by configuring the depth so that the degree of depth increases as the distance from the light source increases, and the present invention has been completed.

In other words, the gist of the lighting panel of the present invention is to provide an optical fiber sheet in which a plurality of core-sheath optical fibers are formed into a sheet shape, with at least one end optically coupled to a light source and having a light leakage portion on at least one side, and the optical fiber sheet. It consists of a front panel placed on the front side of the optical fiber sheet, and a reflective layer placed on the back side of the optical fiber sheet, and the light leakage area is formed by multiple scratches reaching from the optical fiber sheath to the core, and the light leakage area is formed on the side closer to the light source. Towards the far side, the light leakage width of the light leakage part changes and becomes wider, and the density of scratches changes and becomes larger.
In addition, the depth of the scratches varies and becomes deeper, and is characterized by the ability to uniformly irradiate the entire illumination surface.

In a preferred embodiment of the invention, the light leakage width of the light leakage portion, the flaw density, and the flaw depth are changed continuously or stepwise in proportion to the distance from the light source side end of the optical fiber. I can do it.

As one of the preferred embodiments of the present invention, the light leakage portion can be arranged on the reflective layer side.

As another preferred embodiment of the present invention, the light leakage portion can be arranged on the front panel side.

As yet another preferred embodiment of the present invention, an optical fiber having light leakage portions on both the front and back surfaces can be used.

As one of the preferred embodiments of the present invention, the surface panel and the optical fiber sheet can be bonded together, and the optical fiber sheet and the reflective layer can be bonded together using an adhesive layer.

[Function] In the lighting panel of the present invention, the light leakage portion of each optical fiber is controlled, and the density of flaws and their depth are changed depending on the distance from the end on the light source side, and the probability of light leakage and the amount of light leakage are determined. Furthermore, in order to achieve good uniformity and afterglow amount control, the light leakage width is controlled.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a lighting panel according to an embodiment of the present invention. This lighting panel includes an optical fiber sheet l formed into a sheet shape of a plurality of core (1b), sheath (1c) structured optical fibers 18, which are optically coupled to a light source 2 at one focused end and have a light leakage portion 6 on one side. , a front panel 3 disposed on the front side of the optical fiber sheet 1, and a reflective layer 4 disposed on the back side of the optical fiber sheet.

FIG. 2 shows a sectional view of the illumination panel of this embodiment. As shown in this figure, the surface panel 3 and the optical fiber sheet 1 are bonded by the adhesive layer 5, and the optical fiber sheet 1 and the reflective layer 4 are bonded by the adhesive layer 5, so that these are integrated. has been done.

The material of the optical fiber used in the lighting panel of the present invention is not particularly limited, but it is preferable that the core is made of plastic for ease of handling. The thickness of the optical fiber is important from the viewpoint of handling. The thickness can be appropriately selected depending on the application, but it is preferably φ3 or less, taking into consideration the required amount of light, that is, brightness. Optical fibers can be formed into a sheet by any method that can arrange a plurality of optical fibers 18 in a sheet shape, and the resulting sheet may be, for example, one in which optical fibers are aligned and fixed with adhesive or the like. There are also optical fibers in which the optical fibers themselves are fused together, and optical fibers in the form of a fabric.

The surface panel used in the illumination panel of the present invention may or may not have characters, pictures, etc. for display, and the transparency is not limited by the present invention. When it has expressions such as letters or pictures, it can be used as a display board, and when it is used as a backlight for liquid crystal display, it is better to use it as is. Usually, a completely transparent plate is not used, but a plate that has a certain degree of diffusion function is used.

In the reflective layer used in the lighting panel of this invention, usually,
Any of commercially available reflective tapes, reflective sheets, and reflective plates may be used (depending on the application, the selection can be changed as appropriate depending on the different diffusion effects during reflection).

The pattern, light leakage mechanism, uniformity, etc. of the light leakage portion in the lighting panel of this example will be explained using the accompanying drawing showing a typical example in which the light leakage portion is arranged on the front panel side.

FIG. 3 shows cases in which light leaks from a scratch 6a formed in the light leakage part 6, and cases in which light leaks from the scratch 6a formed in the light leakage part 6, and cases in which the optical fiber 1a is directly connected to the optical fiber 1a without light leakage.
A schematic diagram of a typical ray of light traveling inside is shown. Here, the optical fiber 18 consists of a core 1b and a sheath layer 1c, and the flaw 6a breaks through the sheath layer 1c and reaches the core 1b.

As shown in Figure 3, the light traveling on the center side is
Because light leaks from deep scratches but not from shallow scratches, scratch 6
It can be seen that the probability of light leakage from a is related not only to the density of scratches but also to their depth.

In the light leakage portion of the lighting panel of the present invention, the depth of the scratches on the side closer to the light source is shallow, and the depth of the scratches on the side farther from the light source is deeper.

FIG. 4 shows a schematic plan view and a cross-sectional view of an optical fiber sheet formed by a hot stamping method without controlling light leakage parts. In FIG. 4, the shaded portions are light leakage portions 6, and the straight lines between the light leakage portions 6 indicate the boundaries where the optical fibers are joined. The illustrated diagram is an example in which the light leakage width is constant.

As can be understood from this schematic diagram, the light leakage width is only a fraction of the diameter of the optical fiber 18, and if a commonly used hot stamping device is used, at most one of the entire circumference of the optical fiber 18 can be used. /6.

In the light leakage portion of the lighting panel of the present invention, the light leakage width is narrow on the side closer to the light source, and the light leakage width is wider on the side farther from the light source.

This is the third method for controlling the light leakage part of each optical fiber.
As explained in detail in the figure, the probability of light leakage and the amount of light leakage are controlled by changing the density of scratches and their depth depending on the distance from the light source side edge, and further, good uniformity and amount of afterglow are achieved. This is because it is necessary to control the light leakage width in order to achieve control.

By appropriately controlling the parameters related to the light leakage part in this way, the light incident on the optical fiber sheet will partially leak while traveling through each optical fiber, reducing the amount of afterglow at the final end to almost zero. In addition, it is possible to achieve uniformity when observing the entire optical fiber sheet from above.

Specifically, in this invention, it is desirable to increase the width of light leakage in direct proportion to the distance from the end of the optical fiber sheet on the light source side. It is also possible to change the light leakage width, the flaw density, and the flaw depth continuously or stepwise in proportion to the distance from the light source side end of the optical fiber.

FIG. 6 shows an example of the obtained light leakage part. In the embodiment shown in the figure, the light leakage width is narrow on the left side near the light source, and as it moves away from the light source, the light leakage width becomes wider and changes linearly.

An example of a method for preparing an optical fiber sheet for a lighting panel according to the present invention is shown below.

Here, it is manufactured by an industrially advantageous hot stamping method, and in this hot stamping method, the thickness of the cushion sheet placed under the optical fiber sheet is changed continuously or stepwise, and the light leakage width of the light leakage portion is changed. The density of scratches and the depth of scratches are controlled to have a gradient.

The obtained optical fiber sheet is assembled into a lighting panel by joining the surface panel and the reflective layer with the adhesive layer.

As shown in FIG. 3, when there are scratches 6a with the same density and depth, it is understood that the larger the light travel angle θ, the easier the light leaks.

The light source used in the lighting panel of this invention is the fifth light source.
As shown in the figure, there is a reflector type (Figure 5 (a)), a lens type (Figure 5 (b)), a standard type (Figure 5 (
C)) etc. Regarding these emission angle distributions,
Usually or in general, the angle of the emitted light increases in the order of standard type>reflector type>lens type, and includes many light rays with a large θ as shown in FIG. On the other hand, when using the same output light source, the light energy that can be input to the optical fiber is as follows: - Reflector type for boat fishing〉Type with lens〉
Showing the highest characteristics in order of standard type. Therefore, it is desirable to select a light source depending on the application and required characteristics. In the lighting panel of the present invention, preferred light sources include a reflecting mirror type and a lens-equipped type.

This invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention.

For example, in the illustrated embodiment described above, the light leakage portion formed in the optical fiber sheet was placed on the front panel side, but the light leakage portion may be placed on the reflective layer side. The performance of the completed lighting panel varies depending on the size and density of the scratches, the distribution of the emission angle of the light from the light source, the presence or absence of an adhesive layer, etc., and the placement of the light leakage area will affect the uniformity of brightness, brightness, etc. This will affect the absolute value of sharpness, sharpness, etc., so it is desirable to select it each time according to the purpose.

In the above embodiment, the parameters related to the light leakage part, that is, the light leakage width of the light leakage part, the density of scratches, and the depth of the scratches, continuously change in proportion to the distance from the light source side end.
It can be changed stepwise as shown in the figure.

In addition, in the above embodiment, the light leakage part was provided on one side of the optical fiber sheet, but an optical fiber sheet with light leakage parts on both the front and back sides may be used, which requires a little extra processing effort. However, as long as the light leakage portion formation pattern is appropriate, it is possible to obtain effects similar to or greater than that of the single-sided case.

Furthermore, in the illustrated embodiment, there is only one light source, but the light sources may be arranged at both ends of the optical fiber sheet. It is sufficient that the light leakage width of the light leakage portion is narrowed, the density of scratches is lowered, and the depth of the scratches is shallower.

[Effects of the Invention] As is clear from the above description, the present invention provides the following effects.

(1) The entire illumination surface can be uniformly irradiated and the light energy traveling within the optical fiber can be utilized with high efficiency.

(2) Since it can be easily manufactured by a hot stamping method, a uniform and highly efficient lighting panel can be easily manufactured industrially.

(3) By appropriately controlling the parameter 3 regarding the light leakage part, it is possible to correspond to various types of light sources,
Uniformity of the lighting panel can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the appearance of a lighting panel according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the lighting panel of the embodiment shown in FIG. 1, and FIG. 3 is a ray of light inside an optical fiber. FIG. 4(a) is a plan view showing an example of an optical fiber sheet subjected to light leakage treatment using the hot stamping method. FIG. 4(b) is a cross section of the sheet ρ shown in FIG. 4(a). Figure 4(C) is a cross-sectional perspective view of the sheet shown in Figure 4(a), and Figures 5(a), (b) and (c) are one of the light sources that can be used in the present invention. 6 is a plan view of an optical fiber sheet showing a linear pattern of light leakage portions according to the present invention; FIG. 7(a) is a plan view showing a conventional light leakage portion formation pattern; FIG. ) is a diagram showing the relationship between the flaw density and the distance from the light source in the pattern of FIG. 7(a), and FIG. 8 is a plan view of an optical fiber sheet showing a stepwise pattern of light leakage parts according to a modified example of the present invention. It is. 11. Optical fiber sheet 1a9. Optical fiber 1b1. Core IC9, sheath layer 21. Light source 311 Surface panel 410 Reflective layer 51. Adhesive layer 6, light leakage portion 6a0. Distance from the light source end

Claims (1)

[Scope of Claims] 1. An optical fiber sheet in which a plurality of core-sheath optical fibers are formed into a sheet shape, with at least one end optically coupled to a light source and having a light leakage portion on at least one side; and a front surface side of the optical fiber sheet. a surface panel disposed on the optical fiber sheet, and a reflective layer disposed on the back side of the optical fiber sheet, and the light leakage portion is formed by a plurality of scratches extending from the sheath to the core of the optical fiber, and the light leakage portion is formed on the side closer to the light source. Toward the side far from the light leakage area, the light leakage width of the light leakage part changes and becomes wider, the density of scratches changes and becomes larger, and the depth of the scratches changes and becomes deeper, uniformly covering the entire illumination surface. An illumination panel characterized by being able to emit light. 2. The light leakage width of the light leakage part, the density of scratches, and the depth of scratches,
2. The lighting panel according to claim 1, wherein the lighting panel continuously changes in proportion to the distance from the light source side end of the optical fiber. 3. The light leakage width of the light leakage part, the density of scratches, and the depth of scratches,
2. The lighting panel according to claim 1, wherein the light intensity changes stepwise in proportion to the distance from the light source side end of the optical fiber. 4. Claim 1, wherein the light leakage part is arranged on the reflective layer side.
, 2 or 3. 5. The lighting panel according to claim 1, 2 or 3, wherein the light leakage portion is arranged on the front panel side. 6. The lighting panel according to claim 1, 2 or 3, wherein the optical fiber has light leakage portions on both the front and back surfaces. 7. The lighting panel according to claim 1, 2, 3, 4, 5, or 6, wherein the surface panel and the optical fiber sheet are bonded together, and the optical fiber sheet and the reflective layer are bonded by an adhesive layer.