JPH0465007A - Uniform illumination planar light source panel - Google Patents

Abstract

PURPOSE:To improve the homogeneity and intensity of a planar light source panel by providing a white or silver belt-shaped edge section reflecting layer on the surface edge section of a planar light source panel body on the side not faced to a light source. CONSTITUTION:A film holder 17 is integrally molded with a flat base 18 with a rear film reflecting layer 24 on the bottom wall face and erect pieces 19... erected with a reverse L-shaped cross section on three sides of the base 18 not faced to a light source, horizontal rear faces of the erect pieces 19 are arranged along the longitudinal direction on the surface edge section of a resin substrate on the side not faced to the light source to form a belt-shaped edge section reflecting layer 21, and the rear faces of the erect pieces 19 are formed into an end face reflecting layer 22 for the end face on the side not faced to the light source. Homogeneity is secured even when a planar light source panel body is made thin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a surface light source panel for edge light illumination used in various surface light source devices such as liquid crystal backlights, illuminated displays, illuminated signs, and illumination bodies. This invention relates to a uniform illumination surface light source panel that achieves uniform illumination.

[Prior Art] This type of surface light source device has a light source such as a fluorescent lamp installed on one end surface or multiple end surfaces of a surface light source panel body, and supplies incident light from the light source to the surface light source panel to provide uniform light over the entire surface. The lighting should be bright and bright.

The surface light source panel body uses a transparent resin substrate made of acrylic or the like with a high light transmittance and has a thickness of several mm, for example, 5 to 6 mm, either singly or in multiple layers.One side of the transparent resin substrate, generally the back side, is used. A diffused reflection surface with a stepless pattern screen-printed with white ink or a diffused reflection surface with minute dots and lines formed by shot blasting is formed to diffusely reflect the incident light inside the substrate, and a surface light source is used. On the front and back sides of the panel body, a surface coating diffusion layer made of, for example, a polyester sheet that diffuses the diffusely reflected light to produce illumination light, and a backside coating reflective layer made of a polyester sheet, metal foil, etc. to prevent the diffusely reflected light from being emitted out of the plane are disposed. It is said that

[Problems to be Solved by the Invention] Such a surface light source device can have a certain degree of uniformity and brightness, but on the other hand, it is necessary to thin the transparent resin substrate used for the surface light source panel body, that is, to reduce the thickness of the conventional surface light source device. Several mm to 2
When the wall thickness is reduced to ~3 mm or less, for example, about 1.5+ nm, there are bulging dark areas near the edge on the side not facing the light source where the brightness is lower than at other positions. (Also, when the wall thickness is reduced, the background of the diffused reflection surface tends to appear in the surface covering diffusion layer, resulting in a loss of uniformity in the illumination of the surface light source panel.

These problems can be solved to some extent by, for example, making the surface coating diffusion layer thicker (or laminating two polyester sheets), but such measures will greatly reduce the brightness that can be obtained and are not practical. do not have.

Surface light source devices are often installed internally in other devices, especially as liquid crystal backlights, and in such cases, it is important to make the overall size more compact, that is, to make the surface light source panel thinner. However, as mentioned above, conventional methods have the problem of not being able to meet such demands.

The present invention has been made in view of these problems, and its purpose is to provide a uniform surface light source panel that can ensure uniformity even if the surface light source panel body is made thinner. .

[Means for Solving the Problems] In accordance with the above object, the present invention comprises a transparent resin substrate forming a diffused reflection surface, and a surface coating diffusion layer and a back surface coating reflective layer disposed on the front and back sides of the transparent resin substrate. A surface light source panel body for edgelight illumination, characterized in that a uniform illumination surface is provided with a band-shaped edge reflection layer of white to silver color disposed at the edge of the surface of the surface light source panel body on the side not facing the light source. Light source panel (Claim 1) The edge reflective layer of Claim 1 is continuously integrated with a surface-coated diffusion layer and/or a back-coated reflective layer in a bag shape,
A uniform illumination surface light source panel (Claim 2), characterized in that it is formed into a U-shape or a C-shape and is arranged in an annular manner on a surface light source panel body; A uniform illumination surface light source panel (Claim 3) and a uniform illumination surface light source panel characterized in that the front surface coating diffusion layer and/or the back surface coating reflective layer of Claim 1 are disposed with a slight gap between the surface light source panel body and the surface light source panel body (Claim 3) and Claim 1 The present invention relates to a uniform illumination surface light source panel (Claim 4) characterized in that the back-coated reflective layer of Claims 3 to 3 extends to the light source side and covers the outer periphery of the light source, and each of these is an invention. The gist of this is to solve the above problem.

[For production]

The decrease in brightness near the edges of conventional panels is due to the fact that the incident light that travels through the surface light source panel's interior is diffusely reflected and emitted at the edges, and is not used sufficiently as illumination light. However, in the present invention, the band-shaped edge reflective layer disposed at the edge of the surface still contributes to the diffuse reflection of incident light and also reduces light from this edge. By preventing the light from being emitted and allowing it to be used again as illumination light, it appears that the reduction in brightness that occurs in the bulges at these edges is suppressed.

Furthermore, since the second aspect of the present invention naturally extends to the end face of the transparent resin substrate, it further promotes the return use of this light as illumination light.

In addition, in claim 3, the presence of a small gap isolates the diffused reflection surface of the transparent resin substrate from the front-covering diffusion layer or the back-covering reflective layer, so that these Prevents it from appearing through the coating diffusion layer and ensures uniformity.

Furthermore, in claim 4, after ensuring each of the above uniformities,
The light emitted toward the outer periphery of the light source is reflected and supplied to the surface light source panel body, thereby improving the efficiency of supplying incident light by the light source.

[Embodiments] The present invention will be further explained below with reference to the drawings showing embodiments. In FIGS. 1 to 4, 1 is a portable type word processor, and this word processor 1 has a main body 2 equipped with a keyboard section 3. and a tilting display section 4 which is connected to the main body 2 so as to be tiltable and is accommodated therein in a face-to-face overlapping manner.

The tiltable display section 4 is constructed in the form of a wide flat plate with a thickness of about 10+++s, and is provided with a liquid crystal display screen protected by a transparent protection panel 5 on the front side. A surface light source device 7 is built in to backlight the liquid crystal display panel 6.

The surface light source device 7 includes, from the front side, a surface covering diffusion layer 8 made of a white polyester sheet, a surface light source panel body 11 . A surface light source panel 10 comprising a back coating reflective layer 24 made of thin vinyl chloride integrally formed with band-shaped edge reflective layers 21 on both sides, and a sheep disposed on one side of the surface light source panel 10. It is equipped with a light source 26 and a thin and compact inverter (not shown).

The surface light source panel body 11 uses a single transparent resin substrate 12 made of acrylic thinned to a thickness of 211III and has vertical and horizontal dimensions of, for example, 135 x 200 mm, and has almost the entire surface of the back surface side, which is the side surface, with a slight edge remaining. The white to milky white reflective surface 13 is formed in a stepless pattern distributed at high density over the area, for example, by ink screen printing as shown in Japanese Patent Application No. 2-54716.

In this example, the diffused reflection surface 13 is parallel to the end surface 15 on the side facing the light source 20 in the inward direction of the spaced surface and steplessly changes its area ratio to 2.
In order to eliminate non-uniformity in brightness due to reflected light, it is arranged so that the maximum area ratio is achieved at an intermediate position near the end on the non-light source side. In the longitudinal direction including this maximum area ratio portion, a width portion of about 10% is particularly formed as a band-shaped solid or a solid printed diffused reflection surface portion 14 with a high density to the extent that it can be regarded as the same.

The resin substrate 12 on which the diffused reflection surface 13 is formed is made by cutting out a predetermined original plate with the above dimensions, but each of the end surfaces 15 and 16, which are four sides in this example, is free from cutter scratches caused by cutting. The end surface finish is applied to make it disappear 6
In this example, this end surface finish is done by cutting, and is made by Asahi Megalo Co., Ltd.'s Plastic Beauty PB-
This is done using a 1000 (trade name) cutting and finishing machine.

That is, among the four sides, the light source facing end surface 15 that closely faces the incident light supply light source 26 has a cutter feed speed of the cutting finishing machine of about 20% of the maximum speed of 1.5 m/min for mirror finishing, which is about 1.2 m/min. By slowing down the surface roughness, the surface is roughened to have minute irregularities, and this end surface 15 is used as a rough entrance surface.

The reason why the end surface 15 is made into a rough entrance surface is because the light source 26
By allowing the incident light to pass through, the light is diffused non-directionally immediately after the incident, and the diffused reflection by the diffused reflection surface 13 near the light fi 17 is forcibly utilized. This is to prevent a decrease in brightness that occurs in the vicinity of a mountain-shaped or trapezoidal shape, or a decrease in brightness that occurs near the end of the light source when the length of the light source is shorter than the length of the end surface, and in particular to achieve a high degree of uniformity over the entire area. .

On the other hand, the other non-light source side end surfaces 16--, excluding the light source-facing end surface]5, are mirror-finished by setting the feed speed to the maximum speed of 1.5 m/min. The reflectance at the end face 16 is increased to temporarily prevent radiation loss of the incident light supplied to the surface light source panel body 11 from the surface light source panel body 11 to the outside.

The surface coating diffusion layer 8 is made of the above-mentioned polyester sheet (trade name, manufactured by Teijin Ltd. Yubo) with a wall thickness of 75 μm, for example, as it is strong (and has excellent light diffusion properties), and this diffusion layer 8 It is provided with a spacing rib portion 9 which is suitably projected downward into a chevron shape by hot pressing.

On the other hand, the back coating reflective layer 24 is 0.2 to 0.5 +++
A white vinyl chloride resin board with +o is suitable for C-shape (+
) The coating holder 17 for coating resin substrates is molded to have a continuous orientation, and the white bottom wall itself is used.

That is, the covering holder 17 includes a flat plate base 18 having a back coating reflective layer 24 formed by the bottom wall surface, and
It is integrally molded with upright protrusions 19 that stand up in an inverted cross-sectional shape on the three sides of the side not facing the light source, and similarly, the back surface of the horizontal side of the upright protrusions 19 is made of resin. A band-shaped edge reflective layer 21 is disposed along the longitudinal direction of the surface edge of the substrate 12 on the side not facing the light source, and the back surface of the rising piece of the rising protrusion 19 is an end face reflective layer for the end face on the side not facing the light source. 22 and Toshishita.

Further, the covered holder 17 in this example further includes a light source 26.
A semicircular curved section 20 is provided with a flat plate base 18 extended on the side and folded back toward the flat plate base 18 side.
The light source coating layer 23 covers the outer periphery of the light source 6.

The surface light source panel body 11 is mounted on this covering holder 17, and each reflective layer is attached to the surface light source panel body 11.
The surface of the covering holder 17 is made to perform a reflective function, and when the surface light source panel body 11 is installed, high frequency waves are applied to the edges of the horizontal surface. That is, the surface covering diffusion layer 8 is disposed on the surface of the surface light source panel body 11.

At this time, slight gaps are formed between the surface light source panel body II and the backside coating reflective layer 24 and band-shaped edge reflective layer 21 of the covering holder 17, and between the front coating diffusion layer 8. Spacers 25 with a slight thickness are inserted and installed in a partially dotted manner, and the above-mentioned voids corresponding to the thickness of the spacers 25 are provided between each reflective layer 21 and 24 to prevent diffusion. A gap with the thickness of the reflection layer N21 is further formed between the layer 8 and the layer 8.

By providing this small gap, it is possible to prevent the diffused reflection surface 13 of the surface light source panel body 11 from appearing through the surface coating diffusion layer 8 due to the gap between the front coating diffusion layer 8 and the back coating reflective layer 24. Moreover, the reflection efficiency can be further improved compared to the case where the reflection M21 is made face-to-face due to the gap between the reflection layer 21 and the strip-shaped edge reflection layer 21.

Note that the end face reflective layer 22 of this example not only primarily suppresses radiation loss through the mirror finishing described above, but also secondarily suppresses loss of incident light from this end face.

In this example, the light source 26 in the figure is a 12V narrow cold cathode tube with a tube diameter of 3.5 mm and a light source brightness of 1,200 cd/m'', which is compact and has a long life with improved electrode durability due to the cold cathode. It's a tube.

According to this example, a uniform and bright illumination luminance of 230 cd/m" can be obtained, which is about 50% brighter than the conventional one, and reduces the brightness decrease that occurs near the edges on the side not facing the light source. In addition, it was possible to obtain a surface light source panel with excellent uniformity over the entire area without any see-through of the diffused reflection surface.

This increases the brightness by about 20% by forming the solid printed diffused reflection surface portion 14 and prevents the brightness from decreasing, which generally occurs in this portion when used as a light source, by extending it to the end surface 16 on the side not facing the light source. By installing the strip-shaped edge reflective layer 21, the brightness increases by about 10%, and the decrease in brightness that tends to occur in a bulging shape on the side not facing the light source is eliminated. While the brightness is improved by several percent by roughening the opposing end surface 15,
The darkness in the vicinity of the light source 26 is eliminated, making it possible to obtain uniform and bright brightness as a whole, and a slight gap is provided between the surface coating diffusion layer 8 and the back coating reflective layer 24. This prevents the diffused reflection surface 13 from showing through, improves light diffusivity, and ensures a higher degree of overall uniformity.Furthermore, by providing the light source reflective layer 23 integrally with the covering holder 17, the light source 26 By increasing the amount of incident light supplied, the brightness is further improved by 15 to 20%.

FIG. 6 shows an example in which a pair of light sources 26 are installed on opposite end sides of the surface light source panel body 11, and in this case, the stepless pattern translucent dot diffused reflection surface 11 has a maximum area ratio portion in the center. In the case of the one shown in the figure, this maximum area ratio portion is printed in a strip-like solid pattern in the same way as above for a width of approximately 20% of the length between the end surfaces 15 and 15 facing both light sources. This is the irregular reflection surface portion 14. Further, in this example, a pair of curved portions 20 having light source reflective layers 23 are installed in alignment with the light sources 26.

Since the rest is the same as the previous example, the same reference numerals are given and the explanation thereof will be omitted. In the case of FIG. 6 as well, brightness and internality were improved by each configuration as described above.

7 to 9 show surface light source panels 2 showing still other examples.
7, 31, and 32, and FIG. 7 shows that the band-shaped edge reflective layer 21 and the back coating reflective layer 24 are arranged alone on the surface light source panel body 11 in the form of a surface, while the surface coating diffuser This is an example in which the layer 8 is disposed via the edge reflective layer 21, and a slight gap is formed between the layer 8 and the surface light source panel body 11.

In FIG. 7, the strip-shaped edge reflective layer 21 is made by adhering a white vinyl chloride tape 28 face-to-face, and the back coating reflective layer 24 is made from a white polyester low-foam sheet (Toshi Co., Ltd. Film Lot). Number 01080
5207) 29 is used to improve the whiteness and reflectance on the sheet side facing the surface light source panel body 11. Note that the whiteness of this low foam sheet 29 is 99%.
(83% for non-foamed ones), reflectance is 97% (88% for non-foamed ones)
), and the density is 0.80g/Cm” (1.49
g/cm") thickness is 188μ.

FIG. 8 shows that the white vinyl chloride tape 28 is bent and adhered to the surface edge and end surface of the surface light source panel body 11 to form a band-shaped edge reflective layer 21 and an end surface reflective layer 22, and the tape 28 is attached to the surface side. The surface coating diffusion layer 8 is disposed with a very small gap between the surface light source panel body 11 and the surface light source panel body 11 , and the surface coating diffusion layer 8 is disposed on the back side with a similar thickness so as to face the surface light source panel body 11 . This is an example of a surface light source panel 31 in which a backside coating reflective layer 24 made of a polyester low-foam sheet 29 is provided.

Further, FIG. 9 shows a vinyl chloride resin plate 30 having a wall thickness of approximately 0.2 to 0.5 ms, which is formed or bent in a cursive shape to reach the back edge of the surface light source panel body 11. , a back coating reflective layer 2 also made of polyester low foam sheet 29
4 is shown as an example of a surface light source panel 32 interposed with a slight gap between the surface light source panel 32 and the surface light source panel 32.

The rest of FIGS. 7 to 9 are the same as the previous two examples.

The illustrated example is as described above, but in carrying out the present invention, the belt-shaped edge reflective layer is made of white or silver-colored resin with high light reflectivity, in addition to the above-mentioned white vinyl chloride or polyester sheet. This type of surface finish can be applied to strips of various materials, including metal or other materials, and may also be coated directly with, for example, a reflective coating, although the reflectance will be reduced somewhat. It can also be formed by

When forming the edge reflective layer using strip material, in terms of edge treatment,
Particularly when using a thin surface light source panel body, it is often convenient to extend the light to this end face as well.

When the edge reflective layer and the back coating reflective layer are formed continuously and integrally, the above white vinyl chloride 0°2 mm = 0.5 mm.
Although it is easy to integrally mold or bend a material with a wall thickness of about A foamed sheet, metal foil, coating agent, etc. may also be provided.

Similarly, the edge reflection layer and the surface coating diffusion layer can be formed continuously and integrally from polyester films made of the same material, but they can also be formed by joining resin sheet materials made of different materials to suit reflection and diffusion. In this case, as shown in FIG. 8, it may extend to the back surface of the surface light source panel body, or the cross-sectional shape may be an appropriate shape such as a flat plate, a U-shape, a C-shape, or the like.

Furthermore, the edge reflective layer, the surface-coated diffusion layer, and the back-coated reflective layer can be continuously integrated to form a bag-like structure with the light source side open. It is also possible to serve as both. However, it is generally preferable to use materials that are more suitable for the purpose.

Further, at this time, if necessary ribs or the like are formed depending on the material, it is possible to prevent the surface coating diffusion layer from sagging and to secure a small gap as described below.

Of course, in the present invention, the edge reflective layer, the surface-coated diffusion layer, and the back-coated reflective layer can each be used alone, but even in this case, they are integrated with the surface light source panel body by high-frequency welding or the like. This makes handling easier.

It is effective to provide a small gap between the diffusion layer or the reflective layer and the surface light source panel in order to eliminate transparency of the diffused reflection surface and improve uniformity, but this small gap is generally 1II.
I11 or less, the above-mentioned 0.2 to 0.5 eu++ level is sufficient. Just make sure that it actually forms a step (
Therefore, it is also possible to provide steps, small protrusions, etc. at appropriate positions on the reflective layer, diffusion layer, or surface light source panel, and to interpose tape.

It is also desirable to cover the outer periphery of the light source with a reflective layer, as mentioned above (it is also possible to provide the reflective layer continuously and integrally with the reflective layer on the back surface using various materials). For example, even when the bag-like structure is used, a surface light source panel body and a light source can be attached.

Furthermore, in the present invention, the resin substrate may be made of a material with good light transmittance such as acrylic or polycarbonate, and the formation of the diffused reflection surface may be performed by means other than screen printing, such as shot blasting or photosensitive treatment of the printed image. , Roughening the end surface facing the light source by various types of cutting and abrasive processing, such as using an obtuse ceramic cutter with the sharp blade removed, Stacking and using surface light source panel bodies, and the shape of the surface light source panel body. Therefore, in the present invention, the specifics of each part such as a diffused reflection surface, an edge reflection layer, a surface coating diffusion layer, a back coating reflection layer, a small gap, etc. are possible. The material, structure, shape, dimensions, number, production, processing means, aspect, use, etc. of the surface light source panel can be variously changed as long as it does not go against the gist of each of the above inventions, and is particularly limited to what has been illustrated and explained above. It's not enough to do that.

[Effects of the Invention] Since the present invention is constructed as described above, in claim 1, it is possible to eliminate the bulge-like reduced brightness portion near the edge on the side not facing the light source, which appears noticeably as the wall becomes thinner. Therefore, the uniformity and brightness of the surface light source panel can be improved.

In addition to this, the second aspect of the present invention is to further improve the brightness to obtain a bright (uniform surface light source panel), and
This eliminates the need for complicated work such as attachment to the edges and end faces of the surface light source panel body, contributing to easier production and improved yield.

Claim 3 provides, in addition to the effects of claim 1 or 2, a surface light source panel that is more uniform by preventing the diffused reflection surface formed on the surface light source panel from being seen through. I can do it.

Furthermore, in addition to the effects of claims 1 to 3, claim 4 can improve the incident efficiency of the light source and further improve the brightness of the surface light source panel.

In this way, the present invention provides bright (uniform,
A uniform illumination surface light source panel can be provided.

[Brief explanation of drawings]

The drawings show an embodiment; FIG. 1 is a perspective view of a word processor, FIG. 2 is an exploded perspective view of a surface light source device, FIG. 3 is a plan view with the surface covering diffusion layer removed, and FIG. The figure is also a vertical cross-sectional view, FIG. 5 is a partially enlarged plan view of the diffused reflection surface, and FIG. 6 is another example, with the surface coating diffusion layer removed. ... Surface light source panel 11 ... Surface light source panel body 12 - ... Transparent resin substrate 13 ... Reflection surface 16 ... End surface not facing the light source 21 ... Band-shaped edge reflective layer 22 ... End surface reflection Layer 23...Light source coating layer 24...Back coating reflective layer 25...Spacer 26--Light source

Claims (4)

[Claims] (1) A surface light source panel body for edge light illumination comprising a transparent resin substrate forming a diffused reflection surface, and a surface coating diffusion layer and a back surface coating reflection layer disposed on the front and back sides of the transparent resin substrate, the surface light source panel body 1. A uniform illumination surface light source panel comprising a white to silver band-shaped edge reflective layer disposed on the edge of the surface of the panel on the side not facing the light source. (2) The edge reflective layer of claim 1 is combined with a surface coating diffusion layer and/or
Or continuously and integrally with the back coating reflective layer in a bag shape, U shape or C shape.
1. A uniform illumination surface light source panel, characterized in that it is formed into a letter shape and is disposed in a covering manner on a surface light source panel body. (3) A uniform illumination surface light source characterized in that the surface coating diffusion layer and/or the back surface coating reflective layer according to claim 1 or claim 2 are disposed with a slight gap between the surface light source panel body and the surface light source panel body. panel. (4) A uniform illumination surface light source panel characterized in that the back coating reflective layer according to any one of Claims 1 to 3 extends toward the light source and covers the outer periphery of the light source.