JPH07159621A - Surface light source device - Google Patents

Abstract

PURPOSE:To improve a surface light source device so that luminance may be drastically improved. CONSTITUTION:Two end faces of an edge light panel 12 are set as an L-shaped incident end face 11, and a primary light source 2 is bent to form an L shape along the end face 11 and disposed to face the end face 11. At such a time, the corner of the end face 11 is formed as a chamfered corner 13 obtained by breaking a corner. Thus, butting on the bent part of the light source 2 which is difficult to be right angle is eliminated and the end face 11 and the light source 2 come as close as possible. A rubber ring 20 is set at the bent part of the light source 2 so as to prevent the contact with the end face 11. Thus, the luminance of the surface light source device A is drastically improved without changing the power consumption thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device used for various illuminations such as liquid crystal backlights and illuminated signboards.

[0002]

2. Description of the Related Art This type of surface light source device has one end face or two opposite end faces of an edge light panel as an incident end face, a primary light source is provided on the incident end face, and the incident light is supplied from the primary light source to the edge light. It is supposed to illuminate the panel.

An edge light panel is a screen, for example, a dot pattern as a light guide means in which dots are arranged in a row direction and a column direction on a transparent substrate made of acrylic resin so as to change the dot diameter toward the primary light source separation direction. The primary light source is a bar light source such as a fluorescent tube or a cold cathode tube, which is arranged by printing by printing.

[0004]

This surface light source device was developed and put into practical use by the present inventors, and is highly evaluated as having high brightness and high uniformity. For example, it is widely used in liquid crystal backlights and the like. ing.

However, for use as a liquid crystal backlight, for example, the color of the liquid crystal display surface is being changed, and for this color liquid crystal display surface, a leap is made compared with the conventional one for black and white liquid crystal display surface. It is necessary to improve the brightness, and it is difficult for the above-mentioned conventional one to be the optimum one for performing necessary and sufficient illumination.

The present invention has been made in view of such circumstances, and the problem to be solved is to make the relationship between the edge light panel and the primary light source suitable so as to realize a dramatic improvement in brightness. At the same time, it is to solve the problems caused by this.

[0007]

[Means for solving the problems] After intensive research,
When a cold cathode fluorescent lamp with the same power consumption and the same diameter, for example, is bent into an L shape, the lamp brightness is reduced by about 5 to 10% compared to a straight one. Adjacent to the L-shaped incident end face with the adjoining two end faces as the incident end face, the brightness of the edge light panel is several tens of percents, especially when the light guide means is a three-dimensional dot hole, it is a dramatic jump to 50%. That is, the primary light source with the same power consumption is bent at the middle position in the longitudinal direction to be the bent primary light source, and the adjacent plural end faces are the bent incident end faces, and the bent incident end faces are bent. We have found that when a primary light source is installed, an extremely suitable relationship between the incident end face and the primary light source can be obtained.

On the other hand, in this case, on the other hand, the bent portion at the middle position in the longitudinal direction of the bent primary light source is bent at an acute angle of 90 ° so that the two end faces of the edge light panel, which is generally rectangular or square, are formed. Since it is generally difficult to do so, the inside, that is, the edge light panel side, tends to have an obtuse angle, for example, a semicircular shape. Therefore, when this folding primary light source is installed on the above-mentioned folding incident end face, the sharp corner at the middle position in the longitudinal direction of the folding incident end face and the obtuse bent portion of the folding primary light source contradict each other. The relative positions of the end surface and the bent primary light source are separated, resulting in a decrease in the amount of incident light supplied to the edge light panel, which is an obstacle to a dramatic improvement in brightness.

Therefore, in order to eliminate the mutual relationship between the corner of the folding incident end face in the longitudinal direction and the obtuse bent portion of the folding primary light source, an inclined surface, a curved surface or a bulging surface is formed. By dropping the corner, the bent primary light source can be provided so that the relative position of the bent incident end face and the bent primary light source are as close as possible, and the incident light can be supplied by the primary light source as much as possible. We have found that it can be an effective measure to increase the number.

Further, when the relative positions are as close to each other as possible, the bent incident end face and the bent primary light source come into contact with each other, and there is a possibility that the bent primary light source is damaged depending on the situation.

Therefore, a small cushioning member such as a stretchable cushioning ring is provided at the corner of the bent incident end face and the bent primary light source at or near the bent primary light source, or, for example, the bent primary light source. It was found that arranging a means for positioning the folded primary light source such as a holder to be fitted with can be an effective measure to prevent such contact and to install the folded primary light source. .

The present invention has been made on the basis of the above findings, that is, the present invention provides an edge light panel having a plurality of adjoining end faces as folding incident end faces, and the above-mentioned folding incident end faces. A bent primary light source bent along the bent incident end face at an intermediate position in the longitudinal direction, and a corner at the intermediate position in the bent incident end face of the edge light panel is inclined and curved. A surface light source device characterized in that a bent primary light source is provided so that the relative positions of the bent incident end surface and the bent primary light source are as close as possible by being angled to form a surface or a polygonal surface. According to claim 2, the edge light panel having a plurality of adjoining end faces as bent incident end faces, and a bent primary bent along the bent incident end faces at a longitudinal intermediate position provided on the bent incident end faces. With a light source Moreover, the relative position between the folding incident end face and the folding primary light source can be adjusted by sloping the corner at the intermediate position in the longitudinal direction on the folding incident end face of the edge light panel to form an inclined surface, a curved surface or a polygonal surface. As close to each other as possible, a small buffer member is provided at least at the corner of the bent incident end face and the bent primary light source bent part or in the vicinity thereof, and the bent incident end face is bent by the buffer member. A surface light source device characterized in that a bent primary light source is provided to prevent contact of the curved primary light source, and an edge light panel having a plurality of adjoining end faces as bending incident end faces, and the above bent A bent primary light source bent along the bent incident end face at a longitudinal intermediate position provided on the incident end face, and a corner at the longitudinal intermediate position on the bent incident end face of the edge light panel. By making a sloped surface, a curved surface, or a polygonal surface so as to make the relative position of the bent incident end face and the bent primary light source as close to each other as possible, and at least to make the angled corner of the bent incident end face. Positioning means for the bent primary light source is arranged at or near the bent portion of the bent primary light source, and the bent primary light source is provided by preventing the contact between the bent incident end face and the bent primary light source by the positioning means. 5. A surface light source device characterized in that
Is an edge light panel in which one or both adjacent two end surfaces are L-shaped bent incident end surfaces, and a folding primary light source is provided at the intermediate position in the longitudinal direction provided on the L-shaped bent incident end surfaces. 2. An L-shaped bent primary light source is bent along the L-shaped bent incident end face.
The surface light source device according to any one of claims 1 to 3, wherein the angled corners of the bent incident end face and the minute buffer member arranged at or near the bent portion of the bent primary light source are L-shaped. A surface light source device according to claim 2 or 4, which is made of a narrow rubber or synthetic resin into which a curved primary light source is fitted and has a stretchable cushioning property. The angled corners of the bent incident end face and the bent primary light source positioning means arranged at or near the bent primary light source bent portion are partially fitted to the upper, lower or upper and lower parts of the bent primary light source. 5. The surface light source device according to claim 3 or 4, wherein the bent primary light source is made of metal or synthetic resin to be fitted in a ring shape, and serves as a holder disposed and fixed in the vicinity of the folded primary light source. Each of these is given as a summary of the invention. It is obtained by a means for solving problems.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically with reference to the drawings showing the following embodiments. In FIGS. 1 to 6, A is a color liquid crystal backlight for a color liquid crystal display surface, 1 is an edge light panel, and 2 is A primary light source, 3 is a translucent diffusion sheet made of, for example, a white polyester film, and 4 is a highly reflective reflecting sheet made of, for example, a white low-foamed polyester film.

In the present embodiment, the edge light panel 1 has a transparent substrate 10 made of an acrylic transparent resin, in which one adjacent two end faces are L-shaped incident end faces 11 and the other two end faces are L-shaped reflective end faces 12. The light guide means 14 is disposed on the back surface of the unit, and is integrally molded by injection molding.
Of rectangular shape, and the primary light source 2 is located at the intermediate position in the longitudinal direction provided on the L-shaped bent incident end face 11 and
L by a cold cathode tube bent along the bent end face 11
It is used as a primary light source for folding.

At this time, the above edge light panel 1
In the present example, the corner at the intermediate position in the longitudinal direction on the L-shaped bent incident end face 11 is rounded off to form a curved surface, and is formed as a rounded corner 13. As a result, the L-shaped bent incident end face 11 and the L-shaped bent incident end face 11 are formed. The L-shaped folding primary light source 2 is provided so as to be as close as possible to the relative position of the folding primary light source 2.

That is, the L-shaped bent primary light source 2 of the cold cathode tube has its glass tube bent at a right angle along the L-shaped bent incident end face 11 at an intermediate position in the longitudinal direction. Due to the nature of the glass tube, it is generally difficult to bend the part to an acute angle of 90 °, and the inside, that is, the edge light panel 1 side tends to have an obtuse angle, for example, a semicircular shape. Edge light panel 1 as shown in
When the corner of the L-shaped bent incidence end face 11 and the obtuse-angled bent part of the L-shaped bent primary light source 2 are contradictory to each other, the L-shaped bent entrance end face 11 has a sharp angle. Since the relative positions of the L-shaped bent primary light source 2 are separated from each other, and the supply amount of the incident light is reduced in inverse proportion to the square of the separation distance, by providing the above-mentioned angled corner 13, By adjusting the relationship between the L-shaped bent incident end surface 11 and the L-shaped bent primary light source 2, as shown by the solid line in FIG. The relative positions of the light sources 2 are made as close to each other as possible so that the supply of incident light by the L-shaped folded primary light source 2 can be increased as much as possible.

Further, in the present embodiment, a minute cushioning member 20 is provided at each of the rounded corners 13 of the L-shaped folded incident end face 11 and the bent portion of the L-shaped folded primary light source 2, and the cushioning member 20 is provided. This prevents contact between the L-shaped bent incident end face 11 and the L-shaped bent primary light source 2.

That is, since the relative positions of the L-shaped bent incident end face 11 and the L-shaped bent primary light source 2 are made as close as possible to each other by the rounded corners 13, the L-shaped bent primary light source 2 becomes L-shaped.
Since the L-shaped bent primary light source 2 may be damaged depending on the situation due to the contact with the B-shaped incident end face 11, the contact can be prevented by providing a minute buffer member 20. is there.

In this embodiment, the cushioning member 20 is a ring made of a narrow rubber in which the L-shaped bent primary light source 2 is fitted and has a stretchable cushioning property. That is, this buffer member 2
0 has a diameter of 1 mm in cross section, and has an inner diameter equal to or slightly smaller than the L-shaped folding primary light source 2 so that the L-shaped folding primary light source 2 is fitted from the end in the longitudinal direction. This is due to an opaque ring whose position is the center of the bent portion. Therefore, this ring is the L-shaped bent incident end face 1 described above.
1 is provided between the corner 13 and the bent portion of the L-shaped bent primary light source 2 so as to prevent mutual contact.

In the edge light panel 1 of this embodiment, the light guide means 14 is provided with three-dimensional dot holes 16 so that the incident light from the L-shaped bent primary light source 2 makes the light uniform and obtains a preferable bright illumination. The L-shaped dot arrays 15 arranged in an L-shape so as to be parallel to the L-shaped folded primary light source 2 and the L-shaped bent incident end face 11 are arranged at equal intervals.
From the other adjacent two end faces toward the corners of the reflecting end face 12 and the L-shaped dot row 15 has the hole diameter of the dot holes 16 arranged toward the corner of the reflecting end face 12 in this example. And the depth are changed steplessly in the expanding direction, and the peak thereof is L-shaped line 17 passing through the intersection of the diagonal lines of the edge light panel 1 or the end face 12 opposite thereto.
In order to make the L-shaped line 17 part located on the corner side of, and to eliminate the variation in the brightness including the part as much as possible, further, for the predetermined L-shaped dot row 15, the hole diameter and depth Is changed stepwise in the direction of expansion toward the in-row direction.

Such a change is caused by the L-shaped bent incident end face 11
When the L-shaped bent primary light source 2 is provided in the position, the incident light in each straight line portion tends to travel in an M-shape in the left-right direction. Therefore, as shown in FIG. It becomes a part where the incident light of progress is combined and becomes extremely bright,
Since C and D are the regions where one of the M-shaped incident lights illuminates independently, changes in the diameter and depth of the dot hole 16 toward the corner of the reflection end face 12 and an L-shaped line passing through the diagonal line. By setting the peak of the above change on the corner side of the reflective end face 12 more, the L-shaped bent incident end face 11
According to the peculiarity of using the L-shaped folded primary light source 2, the light guide means 14 can be extremely preferable. Even in this case, a partial brightness variation may still occur, and the change in the L-shaped dot array 15 is effective in adjusting this and obtaining a very high degree of uniformity.

In the color liquid crystal backlight A of this example, the cold cathode tube of the L-shaped bent primary light source 2 is set to 12V, 20V.
5.9mA, 2.48W power consumption 30,000
When the luminance of the edge light panel 1 was measured with a lamp luminance of cd / m ² , a high luminance of 6,200 cd / m ² was obtained and a highly uniform luminance was obtained. For comparison, a conventional edge light panel with one end face as the incident end face is used,
When the primary light source of a bar light source having a lamp brightness of 33,000 cd / m ² is installed as a cold cathode tube of the same standard as above, the brightness is 4,000 cd / m ² , and therefore the same power consumption is required. The results of the examples show that the brightness is dramatically improved by 50% or more.

FIGS. 7 to 10 show other examples.
FIG. 7 shows an edge light panel 1 in which two adjacent two end surfaces are L-shaped bent incident end surfaces 11 instead of the edge light panel which is an L-shaped bent incident end surface 11. This is an example in which an L-shaped bent primary light source 2 is also provided on each L-shaped bent incident end face 11 in the same manner to further enhance the brightness. In this case, the change of the L-shaped dot row 15 of the light guide means 14 The peak is located in the central part.

Reference numeral 17a in FIG. 5 shows an L-shaped line indicating a portion where the peak of the light guiding means 14 should be set when the central portion is made particularly bright such as a TFT color liquid crystal display surface.

In FIG. 8, the corner-falling corner 13 of the edge light panel 1 is an inclined surface instead of the curved surface, and the buffer member 20 formed by a similar ring is used as the corner-falling corner 13.
And a pair of L-shaped bent primary light sources are used near the bent part,
This is an example in which contact between the L-shaped bent incident end face 11 and the L-shaped bent primary light source 2 is prevented.

In FIGS. 9 and 10, the positioning means 21 for the L-shaped folding primary light source 2 is arranged at the angled corner 13 of the L-shaped folding incident end face and the bent portion of the L-shaped folding primary light source 2. Then
An example in which the L-shaped folding primary end light source 2 is provided by preventing the L-shaped folded incident end face 11 and the L-shaped folding primary light source 2 from contacting each other by the positioning means 21, and in this example, the positioning means 21
The upper part of the L-shaped bent primary light source 2 is a metal holder that is partially fitted, and this holder is screwed to the unit case 5 when the liquid crystal backlight A is unitized. It is arranged and fixed near the light source 2.

Although the illustrated example is as described above, in carrying out the present invention, the folding incident end face of the edge light panel is made into a series of three end faces or four end faces, and is formed into a U-shape or a square-shape and is folded. The curved primary light source shall be bent in a U-shape or a rectangular shape along it, and the corner at the longitudinal intermediate position on the bent incident end face should be rounded off to form a polygonal surface. Roughening a part or all of the incident end face,
When the minute buffer member is a ring, the material should be made of synthetic resin, and the minute buffer member should be made of rubber or synthetic material that is adhered to the angled corner of the bent incident end face or the bent portion of the bent primary light source, for example. The pad is made of resin and has a cushioning property, and the positioning means is made of metal or synthetic resin in which the lower part or the upper and lower parts of the primary light source are partially fitted, or the bent primary light source is fitted in a ring shape. The fixing of the positioning means is performed by, for example, adhering to the front surface or the back surface of the edge light panel so as to project in the direction of the bent primary light source, or bent from the device or equipment in which the surface light source device is installed. Performing so as to project in the direction of the primary light source, and further, the positioning means is a pair of fitting projections and fitting grooves for fitting the bent primary light source, which is installed in the case or the equipment or equipment for installing the surface light source device. Including mounting and fixing cushioning members and positioning means to other parts, using a fluorescent primary tube as the bent primary light source, and using screen printing for the light guide means of the edge light panel. The specific shapes, materials, structures, dimensions, relations, additions, and surfaces of the bent incident end face, the edge light panel, the bent primary light source, the angled corners, the minute buffer member, the positioning means, etc. The usage of the light source device can be variously modified without departing from the gist of the invention, and is not limited to the above-exemplified ones.

[0028]

As described above, according to the first aspect of the present invention, an edge light panel having a plurality of adjoining end faces as folding incident end faces, and a longitudinal incident position on the folding incident end faces at an intermediate position in the longitudinal direction provided on the folding incident end faces. A bent primary light source, which is bent along with the bent light source, and a corner at an intermediate position in the longitudinal direction on the bent incident end surface of the edge light panel is angled to form an inclined surface, a curved surface or a polygonal surface. Since the folding primary light source is installed so that the relative position of the folding incident end face and the folding primary light source is as close as possible, the relative position of the folding incident end face and the folding primary light source can be set. As close as possible,
The supply of incident light from the bent primary light source to the edge light panel can be increased as much as possible, and in combination with making the relationship between the edge light panel and the primary light source suitable, the brightness is dramatically increased. It is possible to provide an improved surface light source device.

According to a second aspect of the present invention, there is provided an edge light panel having a plurality of adjoining end faces as bent incident end faces, and a bend bent along the bent incident end faces at an intermediate position in the longitudinal direction provided on the bent incident end faces. The edge light panel is provided with a primary light source, and a corner at an intermediate position in the longitudinal direction on the bent incident end surface of the edge light panel is bent to form an inclined surface, a curved surface, or a polygonal surface, and is folded to the bent incident end surface. The relative positions of the curved primary light sources are made as close to each other as possible, and a minute cushioning member is provided at least at the angled corners of the folding incident end face and the folded primary light source folded portion or in the vicinity thereof, and the cushioning is performed. The bent primary light source is provided so as to prevent the contact between the bent incident end face and the bent primary light source with a member, and claim 3 is also characterized in that
An edge light panel having a plurality of adjoining end faces as a bent incident end face; and a bent primary light source bent along the bent incident end face at an intermediate position in the longitudinal direction provided on the bent incident end face, Moreover, the relative position between the folding incident end face and the folding primary light source can be adjusted by sloping the corner at the intermediate position in the longitudinal direction on the folding incident end face of the edge light panel to form an inclined surface, a curved surface or a polygonal surface. As close as possible, at least the corners of the bent incident end face and the bent primary light source are arranged at or near the bent primary light source bent portion, and the bent primary light source positioning means is provided, and the bent incident light is bent by the positioning means. Since the bent primary light source is provided so as to prevent the contact between the end face and the bent primary light source, in addition to the above, the bent incident end face and the bent primary light source come into contact with each other, and the bent primary light source is contacted. The light source is damaged Benefit may be a surface light source device for preventing trouble.

According to a fourth aspect, the edge light panel is
An edge light panel in which two or both adjacent two end faces are L-shaped folding incident end faces, and the folding primary light source is located at the intermediate position in the longitudinal direction provided on the L-shaped folding incident end faces, and the L-shaped folding incident end faces. In addition to the above, in addition to the above, the power consumption is the same as that of the conventional one having the one end face or the two opposite end faces as the incident end face. It is possible to provide a surface light source device that surely makes a dramatic increase in brightness.

According to a fifth aspect of the present invention, the angled corners of the bent incident end face and a minute buffer member arranged at or near the bent portion of the bent primary light source, and the L-shaped bent primary light source are covered. 7. A ring made of a narrow rubber or synthetic resin fitted and having an expansion and contraction cushioning property. Further, according to claim 6, the angled corner of the bent incident end face and the bent portion of the bent primary light source are formed. Or, the folding primary light source positioning means disposed in the vicinity thereof is partially fitted on the upper portion, the lower portion, or both upper and lower portions of the folding primary light source, or the folding primary light source is fitted in a ring shape. Alternatively, since the holder is made of synthetic resin and arranged and fixed in the vicinity of the bent primary light source, in addition to the above, a simple structure is used to prevent contact between the bent incident end face and the bent primary light source. Surface light source device It is possible.

[Brief description of drawings]

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

FIG. 2 is a two-fold enlarged plan view showing the relationship between the edge light panel and the bent primary light source and the light guide means.

FIG. 3 is a partially enlarged view showing a relationship between an edge light panel and a bent primary light source.

FIG. 4 is a plan view showing a luminance distribution state by incident light of a bent primary light source.

FIG. 5 is a plan view showing the peak position of the light guide means of the edge light panel.

FIG. 6 is a vertical cross-sectional view of a liquid crystal backlight showing a model of light guide means.

FIG. 7 is a plan view showing another example.

FIG. 8 is a partially enlarged view showing another example.

FIG. 9 is a partially enlarged view showing a positioning means.

FIG. 10 is a partially enlarged vertical sectional view showing a positioning means.

[Explanation of symbols]

 A Liquid crystal backlight 1 Edge light panel 2 Bending primary light source 3 Diffusing sheet 4 Reflecting sheet 5 Unit case 10 Transparent substrate 11 Bending incident end face 12 Reflecting end face 13 Corner drop corner 14 Light guiding means 15 L-shaped dot row 16 Dot hole 20 Buffer member 21 Positioning means

Claims (6)

[Claims] 1. An edge light panel having a plurality of adjoining end faces as a bent incident end face, and a bent primary light source bent along the bent incident end face at an intermediate position in the longitudinal direction provided on the bent incident end face. And a fold incident end face and a fold primary light source by sloping a corner at an intermediate position in a longitudinal direction on the fold incident end face of the edge light panel to form an inclined surface, a curved surface or a polygonal surface. 1. A surface light source device characterized in that a bent primary light source is provided so that the relative positions thereof are as close to each other as possible. 2. An edge light panel having a plurality of adjoining end faces as bent incident end faces, and a bent primary light source bent along the bent incident end faces at an intermediate position in the longitudinal direction provided on the bent incident end faces. And a fold incident end face and a fold primary light source by sloping a corner at a longitudinal intermediate position on the fold incident end face of the edge light panel to form an inclined surface, a curved surface or a polygonal surface. The relative positions of the above are made as close to each other as possible, and a minute cushioning member is arranged at least at the angled corner of the above-mentioned bent incident end face and the bent portion of the folded primary light source or in the vicinity thereof, and the folded member is folded by the cushioned member. 1. A surface light source device characterized in that a bent primary light source is provided so as to prevent contact between the bent incident end face and the bent primary light source. 3. An edge light panel in which a plurality of adjoining end faces are bent incident end faces, and a bent primary light source bent along the bent incident end faces at an intermediate position in the longitudinal direction provided on the bent incident end faces. And a fold incident end face and a fold primary light source by sloping a corner at a longitudinal intermediate position on the fold incident end face of the edge light panel to form an inclined surface, a curved surface or a polygonal surface. The relative positions of the bent primary light sources are arranged at least at the corners of the bent incident end face and the bent primary light source bent portion or in the vicinity thereof, and the positioning is performed. A surface light source device characterized in that a bent primary light source is provided by preventing contact between the bent incident end surface and the bent primary light source by means. 4. The edge light panel is an edge light panel having one or both adjacent two end faces as an L-shaped folded incident end face, and a folding primary light source is provided in the L-shaped folded incident end face in a longitudinal direction. 4. The surface light source device according to claim 1, wherein an L-shaped bent primary light source is bent along the L-shaped bent incident end face at an intermediate position. 5. A narrow width in which an L-shaped bent primary light source is fitted with at least a declining corner of a bent incident end surface and a minute buffer member arranged at or near a bent portion of the bent primary light source. 5. The surface light source device according to claim 2 or 4, wherein the surface light source device is made of rubber or synthetic resin and has a stretchable cushioning property. 6. A positioning means for the bent primary light source, which is disposed at least at the corners of the bent incident end face and at the bent portion of the bent primary light source, or at a position in the vicinity thereof, is provided above, below or above and below the bent primary light source. 4. A holder, which is made of metal or synthetic resin in which both of the parts are partially fitted, or in which the bent primary light source is fitted in a ring shape, is arranged and fixed in the vicinity of the bent primary light source. Or the surface light source device of 4.