JPH03208205A - Lighting device - Google Patents

Abstract

PURPOSE:To obtain an irradiation surface of equal luminance distribution by providing a light diffusing transmission member that is in parallel with the irradiation surface, and that coveres the entire surface of a reflecting surface, and a transmission member whose transmissivity becomes continously larger as the distance from a light source becomes longer, between the irradiation surface and the light source. CONSTITUTION:A light source 3 is stored between an irradiation surface 1 and a reflecting surface 2, and a plate-shaped diffusing transmission member 4 that is in parallel to the irradiation surface, and that coveres the entire surface of the reflecting surface, is provided between the irradiation surface 1 and the light source 3, while a semi-transmission member 5 is provided in parallel to the member 4, and covering the entire surface of the reflecting surface 2, between the member 4 and the light source 3, and the diffusing transmission member 4 is put on a reflecting member 6 having the reflecting surface 2. The member 4 comprises a sheet member, for which a light diffuser is added to a thermoplastic resin such as acrylic resin or polycarbonate resin. The member 5 is used by depositing a semi-transmission layer 9 whose light beam transmissivity becomes continuously larger as the distance from the light source 3 become longer, on the member 4 or on a transmission member 10. The member 5 has a dimming function whereby the thickness is continuously changed in the range of 0 m to 20 m, by deposition method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a planar light source device I used for illumination, etc., and particularly to a planar light source device I used for illumination, etc. Lighting devices that are used as planar light sources to provide uniform illumination, such as display lighting panels for advertisements, LA-type LCD displays, and especially LCD displays for copying machines, word processors, printers, personal computers, LCD televisions, etc. This relates to a lighting device used as backside illumination to provide uniform illumination. [Prior Art] Conventionally, when using fluorescent lamps for indoor lighting, advertising billboards outdoors at night, etc., several fluorescent lamps were placed in parallel, and a light-diffusing plate-like object such as a half-plate was placed on top of the fluorescent lamps. It is common practice to convert the light emitted from a line light source into a pseudo-surface light source by placing it in the Because the light is forcibly taken out in a flat area, the brightness distribution on the flat area where the light diffusing plate is placed sometimes becomes unsightly uneven, and this visually becomes the outline of the fluorescent lamp, making it difficult to use the lighting equipment. The light diffusion plate and the fluorescent lamp must be placed at a considerable distance from each other, which is a problem from the perspective of space saving.

Furthermore, this is not sufficient in view of the recent increasing demand for relatively small planar illumination devices with uniform luminance distribution for backlighting LCD televisions, portable personal computers, and liquid crystal displays.

Therefore, in order to compensate for these drawbacks, it has been proposed in the past to provide a transmissive reflector plate having a dot-like or thin line-like reflection pattern between the light source and the diffuse-transmissive member (Japanese Patent Publication No. Sho 59-
No. 8809! ).

[Problem to be solved by the invention]

However, in reality, even with this conventional device, it is necessary to provide a gap between the light source and the transmissive reflector, and in addition, there is a gap between the reflective part and the transparent part, which are shaped like dots or thin lines. Since they are arranged alternately, it is not possible to obtain a sufficiently uniform illumination surface, and a satisfactory result has not yet been achieved. In other words, the light emitted from the light source is i! of the i3 suitable reflector. i
The light passes through the transparent part and is reflected in the reflective part, resulting in the appearance of dot-like or thin line-like spots and non-uniformity.In order to compensate for this, there is sufficient space between the light source and the transparent reflector. It became necessary to provide a space, and two diffuser-transmitting members were added.
It is necessary to compensate for the non-uniform illumination surface by increasing the thickness of the opening, resulting in a problem that the illumination device becomes thicker.

The present invention aims to accurately eliminate these conventional drawbacks, and aims to provide a compact illumination device that is ultra-thin and can stably provide a uniform illumination surface, with a simple configuration and at low cost. This is what I did.

[Means to solve the problem]

In the present invention, a light source is interposed between a light emitting surface and a reflecting surface, and a light diffusing and transmitting member is provided between the light emitting surface and the light source, parallel to the light emitting surface and covering the entire surface of the reflecting surface, and a light diffusing and transmitting member is provided between the light emitting surface and the light source. This lighting device is characterized by being provided with a semi-transparent member whose light transmittance changes continuously as the distance increases.

〔Example〕

An embodiment of the present invention will be explained using an example of a spread illumination device shown in FIG. A transmissive member 4 is provided, and a semi-transparent member 5 is provided between the diffuse transmissive member 4 and the light source 3 in parallel with the diffuse transmissive member 4 and covering the entire surface of the reflective surface 2,
A lighting device is provided by placing a diffuser-transmitting member 4 on a reflecting member 6 having the reflecting surface 2.

The diffusion transmitting member 4 is a sheet-like member (obtained by adding a light diffusing agent to a thermoplastic resin such as acrylic resin, polycarbonate resin, polyester resin, polyethylene citrus resin, polypropylene resin, or polyvinyl chloride resin). FIG. 1A) Alternatively, a light diffusing agent is applied as a light diffusing layer 8 to at least one surface of a transparent sheet member 7 such as acrylic sheet, polycarbonate sheet, polyester sheet, polyethylene sheet, polypropylene sheet, or PVC sheet. (Fig. 1B), which is uniformly laminated by painting, printing, etc., to a thickness of 0. 1 mm to 2 vAm. Thickness is 0.
If it is less than 1 + * m, a sufficient light diffusion effect cannot be obtained when used as a planar lighting device, and if it is more than 2 mm,
A sufficiently bright illuminated surface cannot be obtained. Preferably 0.2m
If the number of questions is m~1, it will be sufficiently bright and a light diffusion effect can be obtained.

Further, the reflective member 6 having the reflective surface 2 is made of ABS resin,
AS resin, ACS resin, PS resin, PP resin, P? IM
Sheet members made of A resin, PC resin, PET resin, etc., or members formed by injection molding, Agunto,
^l sheet or P with these Ag and Al sheets laminated on at least one side? IMA sheet, PC sheet, PET
It is a sheet, a PS sheet, a PP sort, a PE sheet member, or a metal plate, and the reflectance of the reflective surface 2 is 80% or more, and if it is less than this, sufficient light reflection cannot be obtained, so it should be avoided.

Further, as the semi-transparent member 5, as shown in FIG. 2, a semi-transparent layer 9 is formed by continuously changing the light transmittance so that it increases continuously as the distance from the light source 3 increases. It is used by being laminated on the diffuser-transmitting member 4 or the transmitting member 10. The semi-transparent member 5 is separated from the transmissive member 10 and the semi-transparent layer 9, and the transmissive member 10 has a thickness of 25 μm to 150 μm.
PET sheet, PMMA 'i-t, PC sheet, P
For vC sheets, if the thickness is 25 μm or less, workability is poor due to scratches, bends, etc. when installing a semi-transparent member;
If it is more than m, the illumination device will become thick and the light transmittance will decrease, so it should be avoided.

The semi-transparent layer 9 is formed on at least one surface of the transparent member IO by gravure printing, offset printing, tampo printing, roll coating, wire coating, knife coating, painting, or the like. For gravure printing, offset printing, and screen printing, the depth of the plate is 0 μm to 10 μm.
By printing and drying an ink containing Aerosil, TiOz, pigments, etc. in a binder of one or more of acrylic, polyester, and epoxy resins, the printing thickness is selected appropriately within the range of 0 μm.
It is preferable to form the semi-transparent layer 9 by changing the concentration so that the light transmittance increases continuously as the distance from the light source increases within the range of m to 70 μm.

In this case, as a method of changing the light transmittance, as shown in FIGS. 2(A) and (B), aerosil,
Tie. It is preferable to perform laminated printing 9' with varying pigment concentrations or ink 9'' with varying concentrations as the distance from the light source increases, and then further laminate the layers. Two or more types of ink with different ratios are placed on a transparent member in parallel without gaps so that the light transmittance increases as the distance from the light source increases, and the entire thickness of the semi-transparent member is uniform. They may be printed and formed in such a way that they are lined up.

Here, the light! Two or more types of ink with different transmittance? is acrylic. Polyester type. Aerosil, TiO■, binder made of one or more epoxy resins
Pigment. They have different light transmittances by blending AI powder, phosphorescent pigments, etc. as appropriate.

Further, these may have different hues and different brightnesses. For example, it is sufficient to use a color whose brightness is changed from white to black at appropriate times. The ink used at this time was acrylic as before. Binders such as polyester and epoxy. Aerosil, TiOt. Pigment, carbon. Ummo. AI powder. Add phosphorescent pigments, etc.

In addition, roll coating, wire coating, knife coating, etc. are printed and dried using ink containing Aerosil, TiO, pigments, etc., in a binder made of one or a combination of acrylic, polyester, and epoxy resins, as described above. By printing thickness 0
Continuous light as the distance from the light source increases in the range of μm to 250 μm! It is preferable to form the semi-transparent layer 9 by changing the transmittance so as to increase the transmittance. As a method of changing the light transmittance, the light transmittance can be changed in the same way as in the case of printing, or by continuously increasing the transmittance as the distance from the light source increases, and laminating the semi-transparent layer 9 on the transmittance member 1o to form a shape. It is better to let it be. FIG. 2(C) In order to accurately and continuously change the printing thickness, it is particularly preferable to use gravure printing. Furthermore, painting may be used as a method of forming these semi-transparent layers 9.

Further, instead of being formed on the transparent member 10, the semi-transparent layer 9 may be formed directly on the light source side of the diffusely transmitting member 4.

Furthermore, by using a light diffusing agent as the ink for forming the half +3% N9, it can also be used as the light diffusing agent in the above-mentioned diffuse transmission member type.

Further, as shown in FIG. 2(D), thermoplastic resins containing a light diffusing agent or a light dispersing agent, ie, PC, PMMA. P
V.C., P.S. PP. It may be formed using a semi-transparent member made of PE or the like whose thickness changes as the distance from the light source increases, and injection molding.

It is considered that the semi-transparent layer 9, which is continuously changed and shaped, is set depending on the brightness (brightness) of the light source used, the number of light sources used, and the distance between the light source and the reflective surface.

In the example shown in FIG. 3, a light diffusing agent layer 8 is provided on the front surface of the transmitting member 10 to form a diffuse transmitting member 4, and a member in which a 4' transmitting layer 9 is directly provided on the back surface thereof is placed on the reflective member 6. The lighting device has a uniform illumination surface.

In the example shown in FIG. 4, a light diffusing agent is used in the semi-transparent layer 9, and it is provided directly on the back side of the transparent member 10, thereby serving as both the diffuse-transmitting member 4 and the semi-transparent member 5, and has a good illumination surface. Tasho F
It can be an IA device.

FIG. 5 shows that the semi-transparent member 5 becomes imprinted on the transparent member 10 as the distance from the light source increases as the thickness of the metal yellowing film increases. It is formed by reducing the thickness of J, and the light diffusing part fA' 4 is located on the side opposite to the light source 3 of the semi-transparent member 5.
．． A lighting device is shown in which a reflective member 6 is provided on the opposite side of the semi-transparent member 5 of the light source 3. The transparent member 10 in this case is a PET sheet. PAE sheet. It is a sheet that can be used for decoration such as PE sheet, and the metal coating film is Ag, Ni. Made of Fe, Cu or their alloys.

Further, the thickness of these vapor deposits is 0 μm to 20 μm. If it is 20 μm or more, the light transmittance is low and good brightness cannot be obtained, so avoid it.

Example 1: A PMMA sheet containing a 0.5+nm diffusive agent is used for the diffusing and transmitting member.C Nitto Resin Clarenox-3) The semi-transparent member is a transmitting member. Ink layers with varying concentrations of Aerosil+TiOz were laminated continuously from 0 μm to 40 μm to form a semi-transparent layer.

A φ8mm tubular light source is used as the light source, and the reflective member is A.
BS (Toray, Toyorasoku 500 FWO56) made it look impressive.

As shown in Table 1, a uniform and spotless illumination surface was obtained.

Example-2 Same as Example 1, and the semi-transparent member is transparent member 1.00
'M film 0-15 by Ni, Fe alloy on μmPET
When the shape was .mu.m, a uniform and even illumination surface was obtained.

The characteristics of the illumination surfaces of Examples 1 and 2 and Comparative Example were as shown in Table 1.

Blank below [Effects of the Invention] The present invention provides a light source interposed between an illumination surface and a reflection surface,
A light diffusing and transmitting member is provided between the illuminating surface and the light source, parallel to the illuminating surface and covering the entire surface of the reflecting surface, and the light transmittance changes continuously as the distance from the light source increases. By providing a translucent member with a semi-transmissive member, the vanocrite light beam 13 pass rate can be adjusted without providing a dot-shaped or thin line-shaped reflective part between the light source and the illumination surface as in the conventional case, which improves the brightness distribution. It is possible to obtain a uniform and even illumination surface, and for this reason, the diffuser-transmitting member can also be made thinner, making it possible to create a compact illumination device.
Moreover, the distance between the light source and the light diffusing plate can be greatly reduced, making it easy to make the entire lighting device thinner, and the semi-transparent layer can be easily formed, making it suitable for mass production and having the effect of reducing costs.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIGS. 1A and 5B are longitudinal cross-sectional views, FIGS. The figures are longitudinal sectional views of other embodiments. 1... Lighting surface, 2... Reflecting surface, 3... Light source, 4...
... Diffuse transmission member, 5 ... Semi-transmission member, 6 ... Reflection member, 7 ... Transmission sheet member, 8 ... Light diffusion layer, 9
... Semi-transparent layer, 10... Transparent member.

Claims (5)

[Claims] (1) A light source is interposed between the light emitting surface and the reflecting surface, and a light diffusing and transmitting member is provided between the light emitting surface and the light source, parallel to the light emitting surface and covering the entire surface of the reflecting surface, and a light source disposed between the light emitting surface and the light source. 1. A lighting device comprising: a semi-transparent member whose light transmittance is continuously changed so that the light transmittance continuously increases as the distance increases. (2) The lighting device according to claim 1, wherein the semi-transparent member is a printed layer formed by a printing method and has a dimming function by changing the concentration of ink as the distance from the light source increases. . (3) The lighting device according to claim 1, wherein the semi-transparent member is a vapor deposited layer formed by a metal vapor deposition method and has a dimming function with a continuous thickness change in the range of 0 μm to 20 μm. (4) The semi-transparent member is made of a thermoplastic resin containing a light diffusing agent or a light dispersing agent, and has a dimming function by continuously decreasing the thickness as the distance from the light source increases. Item 1. The lighting device according to item 1. (5) The semi-transparent member according to claim 1, 2, 3, or 4, wherein the semi-transparent member is disposed between the diffuse-transmissive member and the light source, parallel to the diffuse-transmissive member and covering the entire surface of the reflective surface. lighting equipment.