JPH08254615A - Molded edge light panel - Google Patents

Abstract

PURPOSE: To integrally mold an edge light panel to a wedge shape and sufficiently assure the uniformity of luminance by the scattering patterns thereof. CONSTITUTION: The scattering patterns 5 of the edge light panel 1 formed to the edge shape are composed by arranging right circular cones 6 and on the other hand, the depth and arranging density of the cones 6 which are the factors for scattering characteristics are reversed in the degree of scattering in such a manner that the depth is made shallow and the density is respectively made from coarse to dense in the direction of a non-incident end face 4 from an incident end face 3. The scattering characteristics are controlled by the correlative relation between the depth and the density. The change in the depth is specified to 1000 to 20μm and the density is changed by determining a spline curve as the basis for arrangement of the cones 6, by which the scattering patterns 5 having the high uniformity adequate for the edge shape are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded edge light panel used for various backlights such as liquid crystal backlights.

[0002]

2. Description of the Related Art An edge light panel of this type is generally a flat transparent substrate made of, for example, an acrylic transparent resin, and a plurality of minute dots arranged in an equal pitch on the back surface of the transparent substrate by, for example, screen printing. The halftone dot scattering pattern of the halftone dot scattering pattern is defined as the halftone dot area from the incident end face side toward the reflecting end face or the non-incident end face side by enlarging the halftone dot diameter. It is said to be regulated by the stepless increase of the ratio.

It is also possible to obtain an edge light panel of this kind by integrally molding it with a flat transparent substrate and a scattering pattern on the back surface. In this case, the scattering pattern is generally a cone of halftone dots. It is assumed that it is a halftone dot scattering pattern of holes or conical projections, and its scattering characteristics are regulated by the stepless increase and decrease of the halftone dot diameter from the incident end face side to the reflecting end face side by enlarging the diameter. It

[0004]

Among the backlights, the liquid crystal backlight, in particular, is supposed to be built in and mounted on the back surface of the liquid crystal display surface of electronic devices such as personal computers, word processors and car navigators. There is a demand for further downsizing, and in particular for thinning.

As a means for downsizing the electronic equipment, the edge light panel which determines the thickness of the backlight is thinned, but the thinning is also near the limit. Therefore, as an alternative means, an edge light panel having an incident end face corresponding to the diameter of the fluorescent tube light source,
It is expected that a space for accommodating other components will be secured on the back surface of the backlight by forming a wedge shape with the back surface tapered from the incident end surface.

To make the edge light panel wedge-shaped,
Since it is not efficient to plate a wedge-shaped transparent substrate and subject it to screen printing, it is preferable to perform integral molding of transparent resin such as injection molding so as to have a scattering pattern.

Further, if the edge light panel is formed in a wedge shape, the tapered surface shortens the reflection cycle of the incident light. Therefore, while improvement in brightness can be expected, the shortened reflection cycle causes consumption of the incident light. However, the light guiding property is deteriorated, and it becomes difficult to ensure the uniformity of brightness.

In order to ensure the uniformity of the brightness, it is necessary to regulate the scattering characteristics of the scattering pattern provided on the back surface so as to make a stepless increase change in the light source separation direction. In a wedge-shaped edge light panel in which the reflection cycle is shortened in sequence, even if the diameter of the conical hole used for the above molding is increased, the diameter increase considering the shortened reflection cycle is relatively rapid. However, there is a limit to the enlargement of the diameter, and it is not always possible to obtain desirable scattering characteristics. If this is done intentionally, the balance between the diameter on the incident end face side and the diameter on the non-incident end face side will be obtained. However, there is a possibility that it will be difficult to make a stepless change by losing the light, and eventually the light guide property will be impaired, and it will be impossible to ensure the uniformity of brightness.

In order to further regulate the scattering characteristic, it is possible to envisage increasing the diameter of the conical hole so that it becomes deeper toward the non-incident end face side, in addition to or together with the expansion of the diameter.
In this case, since the wedge-shaped edge light panel has a taper on the non-incident end face side, the conical hole penetrates on the non-incident end face side to form a through hole, or even if it does not penetrate, it may be too deep and scaly may occur. As a result, abnormal light emission may occur, which makes it difficult to ensure the uniformity of brightness.

As described above, it is extremely difficult to form a scattering pattern having a scattering characteristic capable of ensuring the uniformity of brightness by using the wedge-shaped edge light panel.

Even if an attempt is made to integrally mold a wedge-shaped edge light panel, when a scattering pattern by a conical hole is used, the conical hole caused by the molten resin is shunted around the protrusion on the mold side corresponding to this conical hole. There is also a problem with the integral molding of the conical hole in that weld marks are likely to be generated between the holes, and when the weld marks are generated, they also emit abnormal light and impair the uniformity of brightness.

The present invention has been made in view of the above circumstances, and a problem to be solved by the present invention is to integrally mold it into a wedge shape and to provide a scattering pattern having a scattering characteristic suitable for ensuring the uniformity of brightness. In addition, it is to provide a molded edge light panel with no possibility of abnormal light emission.

[0013]

According to the present invention, in accordance with the above problems, the scattering pattern is first formed by a conical hole, and the scattering characteristic of the scattering pattern is continuously reduced to the non-incident end face side of the conical hole depth. It is controlled by the correlation between the change and the stepless increase of the arrangement density of the conical holes toward the non-incident end face, that is, claim 1 is directed from the incident end face to the non-incident end face. A transparent substrate having a wedge shape and a scattering pattern formed by a plurality of conical holes arranged on the back surface of the transparent substrate are integrally molded, and the scattering characteristic of the scattering pattern is incident on the conical hole depth. There is a stepless decrease in depth that is maximum on the end face side and minimum on the non-incident end face side, and a stepless increase change in placement density that minimizes the conical hole arrangement density on the incident end face side and is maximum on the non-incident end face side. Regulate by correlation A molded edge light panel characterized by the following: Then, at this time, the stepless decrease in the depth of the conical holes and / or the stepless increase in the arrangement density are made up to the vicinity of the non-incident end face side, and the remainder is the same. Depth and / or arrangement density, that is, claim 2
The stepless decreasing change of depth and / or the stepless increasing change of arrangement density in the conical hole of claim 1 is made to the vicinity of the non-incident end face side, and the non-incident end face side residual portion has the same depth and / or the same arrangement. A molded edge light panel characterized by being a non-changing part of the density, and then a stepless increase in the density of arrangement of conical holes can be used as a means of changing the diameter and the number. In order to preferably ensure the uniformity of brightness, the number is increased by increasing the number in the same direction in the column direction and increasing in the row direction.
The stepwise increase in the arrangement density of the conical holes according to claim 1 or 2 is the same number in the column direction from the incident end face side to the non-incident end face side, and the number is increased in the row direction parallel to the light source. Molded edge light panel characterized by being made by stepless increase and decrease of number, and then concentrating the arrangement of conical holes on the non-incident end face side for the purpose of ensuring optimal brightness uniformity in these cases. As described above, a spline curve for increasing the linear density is used, and the conical holes are scattered on the spline curve with the spline curve as a reference for disposing the conical holes. The conical holes of any one of 3 are scattered on the spline curve with increased linear density so as to be concentrated from the incident end face side to the non-incident end face side at equal pitches or reduced pitches. As a characteristic molded edge light panel Then using a parabolic or radiation that can be used in place of the spline curve for the same purpose, which also be one obtained by the arrangement reference of Kiriana, i.e. Claim 5
Is a molded edge light panel characterized by being formed by a parabola or radiation in place of the spline curve of claim 4, and then, in these cases, the arrangement density of conical holes is also used for the purpose of ensuring optimum brightness uniformity. It defines a preferable range of stepless change, that is, claim 6
The stepless increase or decrease in the arrangement density of the conical holes according to any one of claims 1 to 5, wherein the area ratio of the conical holes has a minimum area ratio of 5% or more,
Molded edge light panel characterized by being performed within the range of maximum area ratio of 80% or less, and then similarly ensuring optimum brightness uniformity, and in these cases, weld marks during molding and abnormalities due to this. For the purpose of preventing light emission, a preferable range of stepless reduction of the depth of the conical hole is defined, that is, claim 7 and steplessness of the depth of the conical hole according to any one of claims 1 to 6. Decrease the maximum depth 10
Molded edge light panel characterized by being performed within a range of 00 μm or less and a minimum depth of 20 μm or more, and also defining a shape and an angle of a conical hole that ensures a suitable or optimum brightness uniformity. And claim 8
A molded edge light panel, characterized in that the conical hole according to any one of claims 1 to 7 has a right circular cone shape and the angle of the cone is 30 ° or more and 60 ° or less. SUMMARY OF THE INVENTION It is a means for solving the above-mentioned problems as well as the problems including the above-mentioned objects.

In the present invention, the conical hole refers to a conical surface (Cone, cone) hole, and can also be referred to as a conical surface hole or a cone hole. Its shape is that of a polygonal conical body. However, it is not limited to the above-mentioned right circular cone.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings showing the following embodiments. In FIG. 1 to FIG. Liquid crystal backlight, 1 is its edge light panel, 10 is a reflective sheet made of a low foam white polyester film laminated on the back surface of the edge light panel 1,
11 is a diffusion sheet made of a milky white polyester film laminated on the upper surface of the edge light panel 1, that is, the liquid crystal display surface side, and 12 and 13 are laminated on the diffusion sheet 11 so that fine grooves are in mutually intersecting directions. A prism film (lens film) 20 made of polycarbonate is a light source having a diameter of, for example, 3 mm, which is a cold cathode fluorescent tube that supplies incident light to the edge light panel 1.

The edge light panel 1 has a transparent substrate 2 having a wedge shape from the incident end face 3 toward the non-incident end face 4, and a scattering pattern 5 formed by minute conical holes 6 arranged on the back surface of the transparent substrate 2. And is integrally molded.

In the present embodiment, the edge light panel 1 has a transparent substrate 2 of, for example, 168 mm × 215 mm and has a wedge shape with the incident end face 3 having a thickness of 3 mm and the non-incident end face 4 having a thickness of 1.2 mm. Yes, for example, it is formed by performing precise integral molding together with the scattering pattern 5 by injection molding of acrylic transparent resin, and the edge light panel 1 is made incident by arranging the light source 20 in close proximity to the incident end face 3. Light supply, scattering pattern 5
The light is guided by the scattering of the light, and the liquid crystal display A serves as the back light for the liquid crystal display surface.

The scattering pattern 5 has a stepwise decreasing change of the scattering characteristics such that the depth of the conical holes 6 is maximum on the incident end face 3 side and is the minimum on the non-incident end face 4 side, and the arrangement density of the conical holes 6 is shown. It is regulated by the correlation with the stepless increase and decrease of the arrangement density which is minimum on the incident end face 3 side and maximum on the non-incident end face 4 side.

In this example, the scattering pattern 5 is such that the conical holes 6 are arranged at a high density as shown in the plan view of the same size in FIG. It is assumed that this was done by spattering at equal pitches / or reduced pitches on a spline (cloud ruler) curve with an increased linear density so as to aggregate from the 3 side to the non-incident end face 4 side. The stepless increase and decrease of the arrangement density of the conical holes 6 is made the same number in the column direction from the incident end face 3 side to the non-incident end face 4 side and increased in the row direction parallel to the light source 20.
It is supposed to be done by the stepless increase of the number.

That is, in this example, the spline curve is
As the arrangement reference of the conical holes 6, for example, the number of lines of this spline curve is set to 163 with 1.2 mm pitch on the incident end face 3 side and 229 with 0.8 mm pitch increased by 66 on the non-incident end face 4 side. The linear density was increased, and the pitch of the conical holes 6 was steplessly reduced in the column direction so that the pitch was 1.2 mm on the incident end face 3 side and 0.8 mm on the non-incident end face side on these spline curves. It is assumed that the dots are scattered due to the reduced pitch, so that the density is increased by itself,
In the row direction, the conical holes 6 are respectively positioned on the straight lines parallel to the light source 20, and the density changes are precisely and regularly performed.

At this time, the conical hole 6 has a right circular cone shape, and the cone angle is preferably 30 ° or more and 60 ° or less, particularly preferably 45 °, that is, the tip conical surface angle is 60 ° or more and 120 ° or less, particularly A 90 ° right angle is commonly used, and the stepless change in the depth of the conical hole 6 is used to obtain a preferable maximum depth of 100.
Within a range of 0 μm or less and a minimum depth of 20 μm or more, a particularly preferable maximum depth is 500 μm and a minimum depth is 100 μm.
The diameter of the conical hole 6 is reduced because it is arranged on the back surface of the transparent substrate 2 in a perforated shape by stepless reduction so that the diameter becomes m. On the non-incidence end face 4 side, the conical holes 6 are arranged so as to be circumscribed to each other and densely arranged, and the range of stepless increase and decrease of the arrangement density between them is secured as large as possible. There is something to do.

At this time, the arrangement density of this example is the same as the conical hole 6
In the area ratio of the diameters, the minimum area ratio is preferably 5% or more and the maximum area ratio is 80% or less. Particularly, the minimum area ratio is 9% and the maximum area ratio is 79%.

Since the changes in the depth and the arrangement density of the conical holes 6 respectively change the scattering characteristics, the depth is maximized and the arrangement density is minimized on the incident end face 3 side, that is, one is relatively deep. The scattering characteristics are regulated by the conical holes 6 and the conical holes 6 having the smallest depth and the highest arrangement density on the non-incident end face 4 side, that is, the relatively shallow one conical holes 6. Changes steplessly,
Since the arrangement density increases steplessly, that is, the conical holes 6 that become shallower and become denser are regulated so that the scattering characteristics increase steplessly, the scattering characteristics of the scattering pattern 5 can be controlled both in depth and arrangement density. It is regulated by the correlation of stepless change.

At this time, since the transparent substrate 2 has a wedge shape, the reflection cycle of incident light is shortened to the non-incident end face 4 side. However, the depth is changed steplessly and the arrangement density is changed steplessly. In order to regulate this by the correlation of the factors that determine multiple scattering characteristics of increasing changes, the range of scattering characteristics changes is expanded, and the changes can be adjusted as much as possible, thus impairing the light guiding property. It is possible to provide a scattering characteristic that makes the brightness uniform according to the amount of incident light.

FIGS. 5 to 7 show another example. In this example, the transparent substrate 2 and the scattering pattern which are the same as those described above are used, but when the edge light panel 1 is integrally formed, the transparent substrate is formed. Further, a plurality of minute diffusion grooves 8 having an isosceles right triangle having a depth of 25 μm are formed on the entire surface of the horizontal plane 2 at a pitch of 50 μm in a direction orthogonal to the light source 20, that is, from the incident end face 3 toward the non-incident end face 4. This is an example in which the horizontal plane is made to be a diffusing prism surface 7 by arranging, and the conical hole 6 of the transparent substrate 2 is made to shine by the scattered light of the incident light by the conical hole 6 in the scattering pattern 5. This is an example in which scattered light is prevented from being visually perceived on the liquid crystal display surface by diffusing on a horizontal plane, that is, on the illumination surface side of the edge light panel 1. Therefore, in this case, the diffusion sheet 11, the prism films 12, 1 Although 3 and the like can be omitted, in this example, the prism film 13 is laminated in the direction orthogonal to the groove 8 in order to further prevent the naked eye.

In FIG. 8, the diffusing groove 8 on the diffusing surface is formed by alternately arranging a right-angled isosceles triangular groove and an isosceles triangular groove expanded to 120 °. Is an example in which the prevention of the above-mentioned naked eyes is enhanced by enlarging.

FIG. 9 to FIG. 11 show still another example. In this example, the diffusion grooves 8 are formed by a very small number of the above-mentioned isosceles right triangles or isosceles triangles of 120 ° which are alternately arranged.
In addition to the orthogonal direction of the light source 20, the light source 20 is arranged in a cross-shaped orthogonal state in parallel with the light source 20. As a result, the diffusion prism surface 7 is further enhanced in diffusivity to ensure the above-mentioned macroscopic prevention and reflection. Sheet 11, prism film 12, 1
In this example, 3 is made unnecessary.

Since the remainder of FIGS. 5 to 11 is the same, the same reference numerals are given and the description thereof is omitted.

Although the illustrated example is as described above, the stepless decrease change and / or the stepwise increase change of the arrangement density in the conical hole are made as close to the non-incident end face side as necessary, and For example, a strip portion on the incident end face side can be a non-change portion having the same depth and / or the same arrangement density. That is, for example, it is possible to make the width of the non-incidence end face the same depth and further increase the arrangement density, to make the arrangement density the same density and decrease the depth, to make the same depth and the same arrangement density, It may be adopted depending on the degree of brightness uniformity and the need, which may be allowed in a liquid crystal backlight or other backlights such as a display stand.

The arrangement of the conical holes is preferably carried out by using the above-mentioned spline curve as the arrangement reference, in order to suitably carry out stepless increase and change of the arrangement density, but instead of this, a parabola or radiation is used as the arrangement reference. Can be The arrangement of the conical holes in this case may be performed in the same manner as in the case of the above spline curve.

The minimum area ratio of 5
% Or more and maximum area ratio 80% or less, it is better to do it within the range, but the above minimum area ratio 9%, maximum area ratio 79%
The above is particularly suitable for use as a liquid crystal backlight for a liquid crystal display surface having a size of about 9 to 10 inches.

The stepless reduction of the depth of the conical hole is performed within the range of the maximum depth of 1000 μm or less and the minimum depth of 20 μm or more in order to secure the scattering characteristics by the conical hole and to perform integral molding such as injection molding. It is easy to obtain good results in preventing the occurrence of weld marks, but if the depth exceeds 1000 μm, for example, if the thickness of the incident end face is several mm, weld marks are likely to occur and the minimum depth is If it is less than 20 μm, it becomes difficult to secure the scattering characteristics, and the maximum depth is 5
It is preferable that the depth is 00 μm or less and the minimum depth is 100 μm or more, because sufficient scattering characteristics can be secured and the generation of weld marks can be surely suppressed.

As the conical hole, one having a shape having a polygonal pyramid may be used. However, it is easy to form the conical shape when, for example, a mother die of a molding die is cut and processed. Moreover, it is preferable in order to sufficiently perform the scattering by the conical holes. In this case, the cone angle is 30 ° or more and 60 ° or less, that is, the tip cone surface angle (apex angle) is 60 ° or more, 120 ° or less.
The following is generally preferable in terms of increasing the arrangement density, but an angle of 90 ° or an angle close thereto (80 ° to 85 ° or more) is particularly preferable from the viewpoint of securing the scattering characteristics.

The stepless increase of the arrangement density of the conical holes is preferably performed by changing the diameter of the conical holes or the number of conical holes. It is preferable to make the both common by changing the both in order to sufficiently control the scattering characteristics due to the arrangement density.

In integrally molding the edge light panel into a wedge shape, providing a diffusion groove on the upper surface and using this as a diffusion surface instead of the diffusion sheet or the prism sheet is performed by one-time integral molding. It is extremely convenient because an edge light panel having both a scattering pattern and a diffusing surface can be obtained.

Further, a transparent resin having a high light transmittance other than the acrylic transparent resin is used, the size of the edge light panel is appropriately determined so as to be enlarged or reduced, and the use as the backlight is other than the liquid crystal backlight. In the practice of the present invention, including the above, the concrete shape of the molded edge light panel can be various, and it is not particularly limited to the above-described one.

[0037]

EFFECTS OF THE INVENTION Since the present invention has been described above, the first and second aspects of the present invention include stepless reduction of the conical hole depths toward the non-incidence end face side so that the scattering characteristics are contradictory, and the conical hole arrangement. Due to the correlation of the stepless increase and decrease of the density toward the non-incident end face side, there is a wedge shape in which the reflection cycle is shortened, and the scattering characteristics are regulated so as to be adjusted according to the amount of incident light, and the brightness is uniform. It is possible to provide a molded edge light panel that secures the property, and on the other hand, does not cause abnormal light emission due to through holes or scales as in the case of applying the conventional technology.

In addition to the above, the third aspect of the present invention can be a molded edge light panel in which the uniformity of the luminance is sufficiently ensured by increasing the number of the same in the column direction and increasing in the row direction.

According to a fourth aspect of the present invention, in addition to the above, the spline curve is used as a reference for disposing the conical holes, and the conical holes are scattered. It can be a molded edge light panel that secures the property.

According to a fifth aspect of the present invention, a parabola or a radiation is used as a reference for arranging the conical holes instead of the spline curve. Therefore, a molded edge light panel having the same brightness as that of the fourth aspect or a brightness equivalent thereto is secured. can do.

In addition to the above, the sixth aspect defines a preferable range of steplessly increasing and changing the arrangement density of the conical holes, so that it is possible to provide a molded edge light panel with sufficient brightness uniformity. .

In addition to the above, the seventh aspect defines a preferable range of stepless reduction of the depth of the conical hole. Therefore, abnormal light emission due to the weld mark is prevented and sufficient brightness uniformity is ensured. It can be a molded edge light panel.

In addition to the above, according to claim 8, the shape of the conical hole and the angle thereof are defined. Therefore, it is easy to obtain a mother die of the die,
It is possible to obtain a molded edge light panel in which brightness uniformity is sufficiently ensured.

[Brief description of drawings]

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

FIG. 2 is a bottom view of the edge light panel showing the scattering pattern.

FIG. 3 is a vertical sectional view showing a model of an edge light panel and a conical hole.

FIG. 4 is a partially enlarged vertical sectional view showing a model of an edge light panel and a conical hole.

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

FIG. 6 is a vertical sectional view showing a model of an edge light panel and a conical hole and a groove.

FIG. 7 is a partially enlarged vertical sectional view showing a model of an edge light panel and a conical hole and a groove.

FIG. 8 is a partially enlarged vertical sectional view showing a model of an edge light panel and a conical hole and a groove of another example.

FIG. 9 is an exploded perspective view of a liquid crystal backlight of another example.

FIG. 10 is a vertical cross-sectional view showing a model of an edge light panel and a conical hole and a groove.

FIG. 11 is a partially enlarged vertical sectional view showing a model of an edge light panel and a conical hole and a groove.

[Explanation of symbols]

 A liquid crystal backlight 1 edge light panel 2 transparent substrate 3 incident end face 4 non-incident end face 5 scattering pattern 6 conical hole

Claims (8)

[Claims] 1. A monolithic molding comprising a transparent substrate having a wedge shape from the incident end face toward the non-incident end face, and a scattering pattern formed by a multitude of minute conical holes provided on the back surface of the transparent substrate. With respect to the scattering characteristics of the scattering pattern, a stepless decreasing change of the depth in which the conical hole depth is maximum on the incident end face side and the minimum on the non-incident end face side, and the conical hole arrangement density is minimized on the incident end face side, A molded edge light panel characterized by being regulated according to the correlation with the stepless increase and decrease of the maximum arrangement density on the side. 2. The stepless decreasing change in depth and / or the stepless increasing change in arrangement density in the conical hole of claim 1 is extended to the vicinity of the non-incidence end face side, and the residual part on the non-incidence end face side has the same depth. And / or a molded edge light panel characterized by being formed as unchanged parts having the same arrangement density. 3. The stepless increase and decrease of the arrangement density of the conical holes according to claim 1 or 2 is the same number in the column direction from the incident end face side to the non-incident end face side and is increased in the row direction parallel to the light source. A molded edge light panel characterized by being made by steplessly increasing the number of conical holes. 4. A spline curve having an increased linear density so that the arrangement of the conical holes according to any one of claims 1 to 3 is aggregated from the incident end face side to the non-incident end face side by equal pitches or reduced pitches. Molded edge light panel characterized by being scattered. 5. A molded edge light panel, which is made of a parabola or radiation instead of the spline curve of claim 4. 6. The stepless increase / decrease in the arrangement density of the conical holes according to any one of claims 1 to 5 is performed within a range where the area ratio of the conical holes is 5% or more in the minimum area ratio and 80% or less in the maximum area ratio. Molded edge light panel characterized by being 7. Molding, characterized in that stepless reduction of the depth of the conical hole according to any one of claims 1 to 6 is performed within a range of a maximum depth of 1000 μm or less and a minimum depth of 20 μm or more. Edge light panel. 8. A molded edge light panel, wherein the conical hole according to any one of claims 1 to 7 has a right circular cone shape and the angle of the cone is 30 ° or more and 60 ° or less.