JPH09236802A - Edge light panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure high luminance of an edge light panel by executing a post- processing suitable for many kinds in small quantities. SOLUTION: Craters 5 by heat processing are bored on a transparent resin substrate 2 by intermittently irradiating the substrate with a laser beam L of CO2 laser while moving the transparent resin substrate 2 and irregular reflection of incident light is adjusted by changing depth, number or length of the craters 5 to make the craters 5 as a light guiding means of the edge light panel. In such a manner, the edge light panel having high luminance and high uniformity is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal backlight,
The present invention relates to an edge light panel used for a surface light source such as a signboard.

[0002]

2. Description of the Related Art An edge light panel of this kind is provided with a light guiding means for incident light which is densely arranged over one surface of a transparent resin substrate, and the light guiding means is transparent. The dots are formed by screen-printing a resin substrate, or the projections or cone holes are formed by injection-molding a transparent resin substrate. These are sparse on the incident end face side and non-incident end face side or The density is further changed under the above-mentioned high-density arrangement so as to make the center position between the incident end faces dense, and it corresponds to the decrease in the amount of incident light from the incident end faces and contributes to uniform surface emission as a whole. Has been done.

[0003]

In particular, an edge light panel used as a liquid crystal backlight is required to be thin due to a demand for a compact liquid crystal display device equipped with the same, and high brightness is required in accordance with the thinness. In order to secure the above, it is preferable to provide the light guide means by the above-mentioned injection molding, and it is not always easy to perform screen printing with high yield on a thin transparent resin substrate, and therefore, an edge light panel by injection molding is required. Is being used.

However, in the case of injection molding, it is necessary to manufacture a mold according to an order, and it takes a long time to manufacture the mold, and the manufacturing cost is high. Therefore, it takes a delivery time and the cost is increased. If there is a point, and if this injection molding is used, for example, an edge light panel with a size up to about 12.1 inches (diagonal line length display; the same applies below; 12.1 inches corresponds to A4 size in area) Although it is satisfactorily obtained, if it exceeds 14 inches, for example, 14 inches or more, due to its thin wall, molding defects, which are considered to be due to defective molten resin flow, are observed, and therefore, edges formed by injection molding The light panel also has a size restriction and cannot support the liquid crystal display surface that is expected to increase in size in the future.

The present invention has been made in view of the above circumstances, and a problem to be solved by the invention is to provide an edge light panel capable of speedily securing a high yield at a relatively low running cost and a high brightness. There is.

[0006]

[Means for Solving the Problems] As a result of researching in accordance with the above problems, post-processing of a light guide means on a transparent resin substrate enables production of a wide variety of products in small quantities and also determines the size of the transparent resin substrate. In any case, the laser processing is used for the post-processing of the light guiding means, so that the crater for thermal processing by laser beam irradiation is formed in the transparent resin substrate. For a short time, a circular crater or a groove-shaped crater that follows the movement trajectory of the laser beam is obtained, and this crater re-hardens the molten resin that remains without sublimation and is integrated with the transparent resin substrate. It becomes a layered structure, and diffusely reflects incident light very suitably, and when this is used as a light guide means, it is possible to secure high-luminance surface emission as an edge light panel. Findings from the fact that led to obtain and,
The present invention has been made based on this finding. According to claim 1, a crater for thermal processing by irradiation of a laser beam is densely formed on one surface of a transparent resin substrate over the entire surface. The edge light panel is characterized in that the crater serves as a means for guiding incident light, and in addition to the above, each of the second aspect and the fourth aspect provides a preferable mode capable of further ensuring the uniformity of surface emission. , Claim 2
The edge light panel according to claim 1, wherein the crater is formed into a plane circular shape having the same diameter and the depth thereof is changed, and the crater is formed into a plane circular shape having the same diameter. The edge light panel according to claim 1 and claim 4, wherein the crater is formed into a straight or curved plane groove shape with the same groove width, and the length is changed. The edge light panel according to claim 1 is characterized in that it is perforated, and these are the means for solving the above problems as the gist of the invention.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings. In FIG. 1 to FIG. 4, A is a liquid crystal backlight, 1 is an edge light panel, 10 is a reflection sheet, 20 is a diffusion sheet, and 30. Indicates a light source.

The edge light panel 1 is provided with a light guide means on one surface of a transparent resin substrate 2 made of acrylic, polycarbonate or the like, and the light guide means covers the entire surface of the transparent resin substrate 2 with the light guide means. The crater 5 is heat-processed by irradiating the laser beam L formed at a high density, and in this example, the crater 5 is formed as a plane circle having the same diameter and the depth is changed. is there.

The transparent resin substrate 2 of this example is made of acrylic resin having a thickness of, for example, 2 mm and having the same thickness as a whole, and is cut into a rectangular shape having a predetermined dimension, for example, 14 inches (diagonal length). Using the thing, the crater 5 of the light guide means,
For example, 20 to 60 lines (400 to 3600 per square) by laser processing on one side surface, especially the back side.
Number), preferably 25 to 50 lines (625 to 2500 per square inch).

For laser processing, for example, a Co ₂ laser is used, and the transparent resin substrate 2 is irradiated with a laser beam L from a single or plural horizontal focusing heads of a laser irradiation device,
For example, 0.2 to 0.3 mm (200 μm to 300 μ
m) to form a plane circular crater 5 of diameter, while fixing the condensing head at a fixed position,
The transparent resin substrate 2 is horizontally moved in the XY direction or one of them,
By irradiating the laser beam L intermittently under pulse control so that the laser beam L is not moved, a high-density predetermined pattern, for example, a matrix array pattern of evenly-spaced vertical and horizontal intervals, and a staggered array in which this is tilted by 45 ° are used. The pattern, or a high-density radiation array pattern in which vertical and horizontal intervals are set so as to exhibit a radial pattern from the light source 10 side, and a pattern such as a spline curve array pattern in which this is changed are drawn as the image of the transparent The depth of the crater 5 is changed by moving the resin substrate 2 and irradiating it with the laser beam L under the control of a computer by CAD / CAM, and further changing the excitation output intensity of the laser beam L in this control. It has been changed.

The depth of the crater 5 is shallow on the incident end face 3 side so as to be steplessly deeper from the incident end face 3 facing the light source 30 toward the reflection end face 4 on the non-incident side. The end face 4 side is deep, for example, 0.0 on the incident end face 3 side.
2 mm (20 μm), 1 mm (1000 μ
m), whereby the diffuse reflection of the incident light of the light source 30 incident on the incident end face 3 is changed so as to be inversely proportional to the light quantity of the incident light to be worn, and the surface of the edge light panel 1 is changed. The light emission is made uniform over the entire surface so that the light can be guided satisfactorily.

The crater 5 is formed by the irradiation of the laser beam L so that the resin in the irradiated portion evaporates and sublimes. At this time, the shape has a surface opening corresponding to the shape and diameter of the laser beam L. The transparent resin substrate 2 has a cross-sectional shape in which the outer periphery is contracted and narrowed in a curved shape in the wall thickness direction to form a dish-shaped or bowl-shaped concave bottom surface, and the laser beam L is shaped into a perfect circle or an ellipse. By irradiating in a circular shape, the planar shape can be changed to a circular shape.

At this time, by irradiating the laser beam L,
The molten resin remaining on the surface of the crater 5 without sublimation is re-cured on the surface to form a re-hardened layer 6, which becomes an integral layer on the transparent resin substrate 2 and covers the surface.
The melt-cured re-hardening layer 6 smoothes the surface and changes the bending ratio of light, which greatly promotes specular reflection and irregular reflection by the surface wall of incident light traveling in the transparent resin substrate 2. The crater 5 emits light brightly and emits light brightly, and high-luminance surface emission as the edge light panel 1 can be secured. For example, the average luminance of the liquid crystal backlight A is as high as 1,600 cd / m ² or more. It can have a high brightness and, in combination with the change in the depth, a high brightness and a high uniformity.

FIGS. 5 to 8 show other examples, in which the crater 5 of the light guide means also provided on the transparent resin substrate 2 is formed into a straight or curved plane groove shape with the same groove width to change the length. 2 is an example of an edge light panel A that has been perforated by diffused reflection of incident light of a light source 30 incident on an incident end face 3 by specular reflection of a surface wall extending in the same direction as the light source 30 and changing the length. By doing so, the amount of specular reflection is changed so as to be inversely proportional to the amount of incident light that wears down, the surface emission of the edge light panel 1 is made uniform over the entire surface, and its light guiding is favorably performed. There is something you can do.

The crater 5 of this example has a diameter of the Co ₂ laser and an excitation output intensity which are constant, and when the laser beam L is irradiated, the transparent resin substrate 2 is horizontally moved under the irradiation to generate a laser beam. A groove-shaped crater is formed in the shape of a semi-circle on both end planes having the same groove width and the same depth along the movement locus of L.

The straight or curved plane groove shape of the crater 5 is formed by a straight bar shape, a curved bar shape, a direct V shape, a curved U shape, or a straight wavy shape depending on the horizontal movement mode of the transparent resin substrate 2. Although it may have a curved wavy shape or the like, the illustrated example has a curved bar shape in which the light source 30 side is recessed. At this time, the crater 5 of this example has a groove width of 0.2 to 0. 3mm (200μm to 300μ
m), the depth is 0.05 mm (50 μm), the incident end face side is short and the reflection end face 4 side is long so as to lengthen the length steplessly, for example, 0.2 mm (200 μm) on the incident end face 3 side, It is assumed that the thickness is changed to 0.8 mm (800 μm) on the reflection end face 4 side.

In the present example as well, the re-hardening layer 6 is similarly formed, and the average brightness of the liquid crystal backlight A is, for example, 1,700.
High brightness of cd / m ² or more can be achieved, and high brightness and high uniformity can be achieved in combination with the above change in length.

Since the remainder is the same as the above example, the same reference numerals are given and duplicate description is omitted.

Although the more preferable example shown in the drawing is as described above, when the crater of the light guiding means is a flat circular shape having the same diameter, instead of the above change in the depth or with the change in the depth. , The number of holes should be changed and the number of holes should be changed so that it is inversely proportional to the amount of incident light that wears down, and it should be used as a means for uniforming the brightness. , It is possible to make a uniform brightness by replacing the above-mentioned change in the length or by changing the number or the depth with the change in the length to make the brightness uniform. Edge light panel, transparent resin, including the means to increase the viewing angle by increasing the viewing angle by mechanically or integrally forming fine prism lines on the surface of the resin substrate (ground side surface) when molding the original plate Board, light guide Each concrete material, shape, structure, size, number, forming method, relationship between these craters, patterns of crater arrangement, etc., and additions to these are in various forms unless they are against the gist of the invention. can do.

[0020]

The present invention is configured as described above.
According to the first aspect of the present invention, the post-processing of the light guide means is performed on the transparent resin substrate so as to support the production of a wide variety of products in a small amount and the transparent resin substrate regardless of the size thereof. By using laser processing for the post-processing of this light guide means, the above-mentioned light guide means can be formed precisely, accurately, reliably and easily by thermal processing of laser beam irradiation, and craters sublime on the surface. The remaining molten resin was re-cured to form an integrated layer on the transparent resin substrate, and diffused reflection of incident light was performed very suitably, and high-luminance surface emission could be secured, speedily. It is possible to provide an edge light panel that can secure a high yield and a high brightness at a relatively low running cost.

In addition to the above, according to claims 2 to 4, an edge light panel with high brightness and high uniformity can be obtained by ensuring the uniformity of surface emission, and diffuse reflection of incident light is caused by a crater-shaped surface wall. It is possible to ensure a preferable high brightness by performing the above-mentioned mirror reflection.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a liquid crystal backlight.

FIG. 2 is a partially enlarged plan view of the rear side of the edge light panel.

FIG. 3 is a vertical sectional view showing a model of a shallow crater of an edge light panel.

FIG. 4 is a vertical cross-sectional view showing a model of a deep crater in another part of the edge light panel.

FIG. 5 is an exploded perspective view of a liquid crystal backlight.

FIG. 6 is a partially enlarged plan view of the back side of the edge light panel.

FIG. 7 is a longitudinal sectional view in the crater longitudinal direction showing a model of a crater of an edge light panel.

FIG. 8 is a vertical cross-sectional view showing a model of a crater of an edge light panel in a direction orthogonal to the crater.

[Explanation of symbols]

 A LCD backlight 1 Edge light panel 2 Transparent resin substrate 5 Crater 10 Reflective sheet 20 Diffuser sheet 30 Light source

Claims (4)

[Claims] 1. A crater for thermal processing by irradiation of a laser beam is densely formed over the entire surface of one surface of a transparent resin substrate, and the crater serves as a light guiding means for incident light. Edge light panel. 2. The edge light panel according to claim 1, wherein the crater is formed into a plane circular shape having the same diameter and is formed with varying depths. 3. The edge light panel according to claim 1, wherein the craters are formed in a flat circular shape having the same diameter, and the craters are formed by changing the number. 4. The edge light panel according to claim 1, wherein the craters are formed into straight or curved plane grooves having the same groove width and are formed with varying lengths.