JPH0550403U - Light guide - Google Patents

Abstract

(57) [Abstract] [Purpose] It is easy to make the brightness of the surface of the transparent plate uniform, the reflection efficiency is high, the brightness is high, and it is easy to make the brightness of a predetermined position of the transparent plate different from the surrounding brightness. thing. A reflection part 6 having a reflectance higher than that of the uneven part is formed at a predetermined position of the uneven part of the light guide 1 having an innumerable uneven part 5 for irregularly reflecting light on the surface of the transparent plate 4. Was arranged such that the ratio of the per unit area to the unevenness 5 becomes smaller as the distance from the light source 2 increases. Also,
On a light guide body having innumerable irregularities 5 that diffusely reflect light on the surface of the transparent plate 4, a reflecting portion 6 having a reflectance higher than that of the irregularities is formed at a predetermined position of the irregularity 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a light guide for illuminating a space such as a room or illuminating a film, a liquid crystal plate or the like that needs transmitted light.

[0002]

[Prior Art]

 Conventionally, a liquid crystal display used in a word processor, a personal computer, or the like generally employs a backlight system in which a liquid crystal plate is illuminated from behind to brighten a display screen.

As shown in FIG. 8, this liquid crystal display includes a liquid crystal plate 50, a milky white translucent diffusion plate 51, a light guide 52 formed of a transparent acrylic plate, a reflection plate 53, and a light guide. A light source 54 that emits light from the end surface of 52 and a reflector 55 that reflects the light of this light source 54 toward the light guide body 52 are provided. When the light from the light source 54 is emitted to the end surface of the light guide body 52, The light propagates through the light guide body 52 and is reflected at an appropriate position to illuminate the liquid crystal plate 50 from the back side so that the image displayed on the liquid crystal plate 50 can be easily seen.

The light guide 52 used in such a liquid crystal display has a conventional structure as follows.

(1) As shown in FIG. 9, a light guide 57 in which a frosted glass innumerable unevenness 56 is formed on one surface of a transparent acrylic plate.

(2) A light guide body 59 in which white ink is printed on a predetermined portion of a transparent acrylic plate as shown in FIG. 10 so that only the printed portion 58 is irregularly reflected.

(3) As shown in FIG. 11, a light guide body 61 in which a thin groove 60 due to a scratch is formed on the surface of a transparent acrylic plate so that the surface luminance is made uniform by the change in the density of the groove 60.

[0008]

[Problems to be solved by the device]

 However, the above three types of light guides have the following problems.

(1) Efficient reflected light can be obtained from the light guide 57, but as the distance from the light source increases, the amount of reflected light decreases and the light becomes darker, and the entire acrylic plate cannot emit light uniformly.

(2) The light guide 59 absorbs light due to the white ink in the printed portion, and efficient light emission cannot be obtained.

(3) The light guide 61 requires a processing machine for making scratches, and in order to obtain highly accurate and uniform light emission, fine control of the shape and density of scratches is required. In addition, it requires a new process of changing the thickness of the plate, resulting in high cost. However, since it is a scratch due to the destruction of the surface, there is a phenomenon of light absorption at the destroyed portion, and high brightness cannot be obtained.

On the other hand, it is possible to create a lighting device such as a wall hanging so that a picture or a pattern is made to stand out by devising the position where the white ink or the scratch is provided on the acrylic plate, etc., but it is printed with the white ink. In this case, there is little difference in light and shade between the part where the picture or pattern is attached and the surroundings, and the contour is not sharp, or the process is difficult when scratched.

One object of the present invention is to obtain a light guide body having a uniform brightness on the surface of a transparent plate, a high reflection efficiency, and a high brightness.

Another object of the present invention is to obtain a light guide body in which it is easy to make the brightness of a predetermined position of the transparent plate different from the brightness of the surroundings.

[0015]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a light guide body having innumerable irregularities on a surface thereof that diffusely reflects light incident from an end surface of a transparent plate, and the light guide body is formed at a predetermined position of the concave and convex portion formed on the surface. A reflective portion having a higher reflectance than the uneven portion is formed.

If the reflection part is arranged such that the ratio of the projections and depressions per unit area decreases as the distance from the light source increases, the brightness of the surface of the transparent plate can be made uniform.

[0017]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

<Structure> In this embodiment, the case where the light guide is used in a liquid crystal display as shown in FIG. 8 will be described. FIG. 1 is a display in which members corresponding to the liquid crystal plate 50, the milky white translucent diffusion plate 51, and the reflection plate 53 of FIG. 8 are omitted, and the flat transparent light guide body 1 and the transparent light guide body 1 are provided. A light source 2 such as a fluorescent lamp, a halogen lamp, a light bulb, and a light emitting diode that irradiates light from the end surface of the light body 1 and a reflection plate 3 that reflects the light from the light source 2 toward the light guide body 1 are provided. There is.

In the light guide body 1, an infinite number of frosted glass-like irregularities 5 that diffusely reflect light are formed on one surface of a transparent plate 4 such as acrylic or glass / silicon rubber. A plurality of reflecting portions 6 having higher reflectance than the uneven portion are formed.

The transparent plate 4 may be colorless or may have a color such as blue or red. Further, the unevenness 5 may be fine scratches or fine unevenness.

The reflecting portion 6 is formed by applying a transparent varnish-like paint to the uneven surface, attaching cellophane tape or the like, adhering a transparent resin, adhering a transparent vinyl material or the like, melting a transparent plate by heat, etc. It is arranged so that the ratio per unit area with respect to 5 becomes smaller as the distance from the light source 2 increases. For example, as shown in FIG. 2, a plurality of circular reflecting portions 6 are arranged at equal intervals along the light source 2 as shown in FIG. 2, and the size of the reflecting portion 6 is reduced as the distance from the light source 2 increases. Reflecting portions 6 are arranged at an equal pitch P in a direction away from 2.

By forming the reflecting portion 6 having a higher reflectance than the uneven portion on the uneven portion provided with the unevenness 5 as described above, that portion becomes flat and the unevenness of the portion is reduced, or the unevenness 5 Disappears, and the light reflectance is higher than that of the uneven portion. For this reason, diffuse reflection is less likely to occur in the reflecting portion 6, and conversely, regular reflection is likely to occur, light absorption in the reflecting portion 6 is small, and compared with the light guide 57 in which the unevenness 56 is simply formed as shown in FIG. The surface becomes brighter and brighter.

Further, in the conventional light guides 59 and 61 shown in FIGS. 10 and 11, when the light hits the printed portion 58 or the groove 60, the light is diffusely reflected there, so that the light amount is reduced. That is, in the conventional light guides 59 and 61, the ratio of the printed area 58 and the groove 58 per unit area increases as the distance from the light source 54 increases, and the ratio of irregular reflection increases toward the light source 54 to increase the light amount. The surface of the light source 54 is dark because the reflectance on the side of the light source 54 is reduced and the brightness of the surface is made uniform.

However, in this embodiment, since the ratio of the reflecting portion 6 to the unevenness 5 per unit area is arranged to decrease as the distance from the light source 2 increases, the ratio of diffusely reflected light increases as the distance from the light source 2 increases. On the contrary, as the light source 2 is closer to the light source 2, the proportion of the normal reflection increases, and the luminance is increased and the surface is brightened and the luminance of the surface is made uniform as compared with the conventional case.

As shown in FIG. 3, the reflecting portions 7 having the same width and long in the direction along the light source 2 may be arranged with the intervals P1, P2, ...

Further, as shown in FIG. 4, the reflecting portions 8 whose widths H1, H2, ... Are narrower as the distance from the light source 2 is increased may be arranged at an equal pitch P.

Further, as shown in FIG. 5, a plurality of reflecting portions 9 may be arranged in the lengthwise direction of the light source 2 so as to become thinner as the distance from the light source 2 increases.

When the light source 3 is, for example, a fluorescent lamp, the amount of light at both ends is smaller than the amount of light in the middle, so the distance between the reflecting portions arranged near both ends in the length direction of the fluorescent lamp is the distance between the intermediate portions. Alternatively, the size of the reflection part may be reduced or the size of the reflection part may be reduced so that the ratio of the reflection parts arranged at both ends in the length direction of the fluorescent lamp per unit area is smaller than that in the middle part.

<Operation> Next, the operation will be described.

As shown in FIG. 1, the light A of the light source 2 incident from the end surface of the transparent plate 4 is diffusely reflected at the position B of the unevenness 5, and the upper surface of the transparent plate 4 is made bright.

The light entering in the path of C is specularly reflected (totally reflected) at the reflecting portion D, and the reflected light is specularly reflected at the E position on the surface and hits the F position of the unevenness 5 to cause diffuse reflection, so that the upper surface is reflected. Brighten. In other words, the incident light C has its emission suppressed at the D position and extends to the F position.

<Modification> One embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment, and the following modifications can be made.

(1) In the above-described embodiment, the invention is applied to the liquid crystal display, but the invention can also be applied to a lighting device such as a wall mount. For example, the reflecting portion 10 can be darkened by forming the reflecting portion 10 into a pattern or a picture as shown in FIG. Further, as shown in FIG. 7, by using the reflection portion 11 around the pattern or the picture, the pattern or the picture can be brightly raised.

(2) As shown in FIGS. 6 and 7, the light source 2 may be arranged on a plurality of end faces of the light guide 1.

(3) The light guide may have innumerable irregularities formed on both sides thereof to diffusely reflect light.

(4) In the above-mentioned embodiment, the reflecting portion is formed transparent, but it may not be transparent as long as the reflectance is higher than that of the uneven portion.

[0037]

[Effect of the device]

 This invention is directed to a light guide having innumerable irregularities on the surface that diffusely reflect light incident from the end face of a transparent plate, and has a higher reflectance than the irregularities at a predetermined position of the irregularities formed on the surface. Since the portion is formed, it is possible to easily make the brightness of the predetermined position of the transparent plate different from the brightness of the surroundings.

Further, by arranging the reflection portion such that the ratio of the per unit area to the unevenness becomes smaller as the distance from the end face of the transparent plate on which light is incident, it is easy to make the brightness of the surface of the transparent plate uniform. It is possible to obtain a light guide having high reflection efficiency and high brightness.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement example of reflecting portions formed in the light guide body of FIG.

FIG. 3 is a plan view showing an arrangement example of reflecting portions formed on the light guide body of FIG.

FIG. 4 is a plan view showing an arrangement example of reflecting portions formed in the light guide body of FIG.

5 is a plan view showing an arrangement example of a reflecting portion formed on the light guide body of FIG. 1. FIG.

FIG. 6 is a plan view showing the configuration of another embodiment of the present invention.

FIG. 7 is a plan view showing the configuration of another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a structure of a conventional liquid crystal display.

FIG. 9 is a cross-sectional view showing a structure of a conventional light guide.

FIG. 10 is a cross-sectional view showing a structure of a conventional light guide.

FIG. 11 is a cross-sectional view showing the structure of a conventional light guide.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide 2 Light source 3 Reflector 4 Transparent plate 5 Concavo-convex 6 Reflector 7 Reflector 8 Reflector 9 Reflector 10 Reflector 11 Reflector

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // F21P 1/00 9032-3K

Claims (2)

[Scope of utility model registration request] 1. A light guide having, on its surface, a myriad of irregularities that diffusely reflect light incident from the end face of a transparent plate, and has a reflectance higher than that of the irregularities at predetermined positions of the irregularities formed on the surface. The light guide body is characterized in that the reflecting portion is formed and the reflecting portion is arranged such that a ratio of the reflecting portion per unit area becomes smaller as the distance from the end face increases. 2. A light guide body having innumerable irregularities on a surface thereof for diffusely reflecting light incident from an end face of a transparent plate, the reflectance being higher than that of the irregularity portion at a predetermined position of the irregular portion formed on the surface. A light guide having a reflection portion formed.