WO2008085161A1

WO2008085161A1 - Backlight panel and manufacturing method thereof

Info

Publication number: WO2008085161A1
Application number: PCT/US2007/000522
Authority: WO
Inventors: Robert M. Krohn
Original assignee: Lighting Panels, Llc
Priority date: 2007-01-09
Filing date: 2007-01-09
Publication date: 2008-07-17

Abstract

The present invention relates to a backlight panel comprising: (a) a transparent plastic lampholder sheet comprising two or more parallel walls supported by intervening parallel spaced-apart longitudinal ribs forming a series of hollow tubes; and (b) one or more lamps wherein each lamp is inserted into one of said hollow tubes. The present invention may further comprise a wiring harness and an inverter or ballast. The twinwall plastic lampholder sheet is thin, durable and lightweight, protecting the fragile lamps and providing a simple method of mounting and wiring. The plastic lampholder sheet may also be slit on one, or both sides, yielding a flexible lightpanel; graduated dots or lines may also be printed onto the surface of the plastic lampholder sheet or translucent materials may be used on the surface of the plastic lampholder sheet to assist in making the intensity of the light across the surface of the sheet more even.

Description

BACKLIGHT PANEL AND MANUFACTURING M MEETTHHCOD THEREOF

TECHNICAL FIELD

[0001] The present invention relates to a fluorescent or light emitted diode

(LED) illuminated backlight panel and more particularly, to an improved backlight panel including a plastic lampholder sheet, comprised of a multiplicity of longitudinal tubes for properly spacing, housing and protecting the inserted fragile fluorescent lamps or LED strips.

BACKGROUND

[0002] In recent years there has been an industry-wide, customer-driven desire for display lightboxes which are very thin; changes in the Americans With Disabilities Act (ADA) mandated lightboxes that could protrude no more than three inches from the wall. Previously, normal interior-use lightboxes were, on the average, five-to-six inches thick. Through creativity and better engineering, top-quality fluorescent lightboxes were able to be manufactured to about three inches in depth; two-sided lightboxes are typically five to six inches deep.

[0003] With the advent of acrylic, edge-lit lightpanels, lightboxes were able to be manufactured to a depth of between one and two inches, but at great expense.

[0004] However, the standard backlit fluorescent lightboxes are very heavy, relatively deep, use a lot of power and have limited lamp life. Edgelit lightboxes are thin, but they are very heavy, very expensive, very difficult to service and are not very bright. The lamps used in edge-lit lightpanels, normally CCFL's (cold-cathode fluorescent lamps) or EEFL's (external electrode fluorescent lamps) are extremely fragile. It is also very difficult, in all forms, to make a thin, bright, curved lightbox or lightpanel.

DISCUSSION OF ART

[0005] U.S. Patent No. 6,674,250, discloses a backlight including external electrode fluorescent lamps and a method for driving the backlight. The backlight includes fluorescent lamps having external electrodes made of an electrically conductive material for wrapping the outer peripheral surfaces including edge cross- sections on both ends of a glass tube with a layer of fluorescent substance applied thereon. The backlight is constructed in a manner that a plurality of such fluorescent lamps are installed at the outer portions of a plastic light guide, and an alternating current type power source is applied from the outside to the fluorescent lamps by installing a plurality of the fluorescent lamps between a reflecting plate and a diffusing plate and electrically connecting them with one another.

[0006] U.S. Patent No. 6,843,584, discloses a backlight device including a plurality of fluorescent lamps each having a tube and lamp electrodes formed at opposing ends of the tube arranged parallel with each other along a first direction, a lower lamp fixing assembly of a first height having a first plurality of grooves disposed along a second direction for holding the ends of the plurality of fluorescent lamps, and an upper lamp fixing assembly having a second height, the upper lamp fixing assembly having a second plurality of grooves, a first end portion have a first width facing the lower lamp fixing assembly, and a second end portion having a second width smaller than the first width, wherein portions of the ends of each of the tubes are exposed at an exterior of the lower and upper lamp fixing assemblies.

[0007] U.S. Patent No. 6,984,056, discloses a lighting device invention including a pair of sockets made of a soft and elastic conductor and arranged facing each other, with which electric power is supplied to EEFL lamps.

SUMMARY OF THE INVENTION

[0008] The present invention relates to a backlight panel comprising:

(a) a transparent plastic lampholder sheet comprising two or more parallel walls supported by intervening parallel spaced-apart longitudinal ribs forming a series of hollow tubes; and

(b) one or more lamps wherein each lamp is inserted into one of said hollow tubes.

The present invention may further comprise a wiring harness and an inverter or ballast.

[0009] It is an objective of the present invention to provide light boxes which utilize the present invention and are lighter in weight, thinner in profile, less expensive to produce, and provide brighter and more even illumination.

BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 - Is an end-view of a plastic lampholder sheet, comprised of:

A. Broad parallel wall (10)

B. Broad parallel wall (20)

C. Longitudinal rib (30)

D. Hollow square tube (40)

[0011] FIG. 2 - Is a perspective view of a plastic lampholder sheet.

[0012] FIG. 3 - Is a perspective view showing lamps inserted into a plastic lampholder sheet.

[0013] FIG. 4 - Is a perspective view of a plastic lampholder sheet in which the hollow square tubes that contain the fluorescent lamps are shorter than the adjacent hollow square tubes, providing for extra protection for the ends of the fluorescent lamps.

[0014] FIG. 5 - Is a perspective view of a plastic lampholder sheet with fluorescent lamps inserted and wiring harness attached. (60)

[0015] FIG. 6 - Is a perspective view showing an LED strip inserted into a plastic lampholder sheet and wiring harness attached. (80)

[0016] FIG. 7 - Is a perspective view of a plastic lampholder sheet which has been slit, cut or otherwise kerfed in order to provide flexibility to the backlight panel.

[0017] FlG. 8 - Is a close-up of the perspective view of a plastic lampholder sheet of FIG. 7, which has been slit, cut or otherwise kerfed in order to provide flexibility to the backlight panel. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention relates to a backlight panel comprising:

The present invention may further comprise a wiring harness and an inverter or ballast. The backlight panel is constructed in a manner that one or more fluorescent lamps or LEDs are inserted into a series of hollow, parallel plastic tubes supported between two parallel plastic walls (Figure 3). The plastic tubes and walls are preferably extruded from polycarbonate, although other plastic types and manufacturing methods may be utilized.

[0019] The tubes and walls of the lampholder sheet may also be manufactured from materials such as scrim or other materials made from fibers, natural or synthetic.

[0020] The tubes of the lampholder sheet may be square, round or of a shape to accommodate the shape of the lamp which is to be inserted into the tube.

[0021] The lampholder sheet of the present invention may be curved by longitudinally slitting-through a series of the hollow, square tubes on one-or-two sides of the sheet (kerfϊng), allowing the sheet to bend, yielding a flexible backlight panel.

[0022] The backlight panel of the present invention is illuminated via fluorescent lamps or LEDs, employing, but not limited to, cold-cathode fluorescent lamps, external electrode fluorescent lamps or LEDs (Figures 3, 5 and 6). These lamps are typically driven by, but are not limited to, commercially available inverters utilizing a square wave, sine wave, fluorescent ballasts or switching power supplies. A wiring harness is utilized to carry the proper voltage, current and frequency to the ends of each lamp or LED (Figures 5 and 6). The lamps of the present invention, either CCFLs, EEFLs, thin fluorescent lamps, or LEDs are protected from shock and breakage by being contained within the tough, rigid, plastic lampholder sheet. By varying the placement of the lamps or LEDs in alternate hollow tubes, the spacing of the lamps or LEDs (the distance between lamps or LEDs) is easily changed, thus altering the numbers of lights and the brightness of the sheet. Double-sided lightboxes can be easily and inexpensively manufactured to under three inches in depth. The rigidity and protection afforded by the plastic lampholder sheet allows for the ease of manufacture of lightpanels for use without the necessity of additional protection by metal or plastic cover-bodies, since the plastic lampholder sheet serves as both protection for the lamps and LEDs and as method of lamp and LED mounting.

[0023] The lamps of the backlight panel of the present invention, either

CCFLs, EEFLs, thin fluorescent lamps, or LEDs are protected from shock and breakage by being contained within the plastic lampholder sheet, either with or without plastic, rubber or synthetic, square, circular, or shaped "O"-ring types of spacers encircling the lamps.

[0024] By varying the placement of the lamps or LEDs in alternate hollow square tubes, the spacing of the lamps or LEDs (the distance between lamps) is easily changed. This change in lamp or LED spacing alters the number of lamps or LEDs used in the lightpanel, thus changing the brightness of the lightpanel and altering the distance needed between the plane of the lamps and an illuminated substrate in order to achieve even illumination across the face of the illuminated substrate.

[0025] The mounting (insertion) of the lamps within the hollow tubes of the transparent or translucent lampholder sheet allows for the very easy manufacture of double-sided lightpanels and lightboxes, since the illumination from the lamps shines out of both sides of the lampholder sheet, if it is transparent or translucent. Double- sided lightboxes can be easily and inexpensively manufactured to under three inches in depth.

[0026] The imprinting of translucent material, dots, lines or other light- reducing methods onto the face of the tubes, directly in front of the lamps, easily allows for increased control of the intensity and evenness of illumination of the light panel.

Claims

CLAIMSWhat is claims:

1. A backlight panel comprising:

(a) a transparent plastic lampholder sheet, comprising two or more parallel walls supported by intervening parallel spaced-apart longitudinal ribs, forming a series of hollow tubes; and

(b) one or more lamps, wherein each lamp is inserted into one of said hollow tubes.

2. The backlight panel of claim 1 further comprising a wiring harness and an inverter or ballast.

3. The backlight panel of claim 2, wherein said wiring harness originates at an inverter or ballast and terminates at the electrodes of said lamps individually or in parallel.

4. The backlight panel of claim 2, wherein said inverter or ballast is connected to said lamp via said wiring harness.

5. The backlight panel of claim 1, wherein one or more of said hollow tubes are imprinted or colored.

6. The backlight panel of claim 5, wherein said imprint comprises a translucent material.

7. The backlight panel of claim 6, wherein said translucent material is an adhesive.

8. The backlight panel of claim 5, wherein said imprint comprises a pattern of dots, lines or shapes.

9. The backlight panel of claim 1, wherein said lamp is a fluorescent lamp.

10. The backlight panel of claim 9, wherein said fluorescent lamp is surrounded at two or more points by a rubber or synthetic, square, circular, or shaped "O"-ring, supporting the lamp away from the walls of the hollow tubes and also behaving as a shock absorber.

11. The backlight panel of claim 1, wherein the plastic lampholder sheet is translucent.

12. The backlight panel of claim 1, wherein said transparent plastic lampholder sheet has one or more of the broad, parallel walls colored with a transparent, translucent or opaque white or color material.

13. The backlight panel of claim 1, wherein said longitudinal ribs are curved.

14. The backlight panel of claim 1, wherein the hollow tubes in the plastic lampholder sheet which contain said lamps are shorter than the adjacent hollow tubes.

15. The backlight panel of claim 1, wherein one or more of said hollow tubes in the lampholder sheet are cut through (kerfed), parallel to the longitudinal ribs, on one of the broad, parallel walls in order to allow the lampholder sheet to bend.

16. The backlight panel of claim 1, wherein said hollow tubes are independently round or square in shape, comprised of two or more broad parallel walls supported by intervening parallel spaced-apart longitudinal ribs, defining a series of hollow square or round tubes, may also be extruded or constructed to define a series of hollow tubes of any desired shape.

17. A backlight panel comprising:

(a) a transparent plastic lampholder sheet, c omprising of two or more broad parallel walls supported by intervening parallel spaced-apart longitudinal ribs, defining a series of hollow square tubes;

(b) one or more LED strips (light-emitting-diode strips), wherein each LED strip is inserted into one of said hollow tubes and wherein said LED strips comprise two or more LED's, placed next to each other, in a line, wired in parallel or in series, attached to a rigid or flexible wiring harness or printed circuit board; and

(c) a wiring harness, each wiring harness originating at a DC voltage source, or any other type of voltage source appropriate for powering said LED strips; the other end of the wiring harness terminating at one, some, or all of the LED strips, used to provide power to the LED strips.

18. The backlight panel of claim 17, wherein a transparent plastic lampholder sheet, comprised of two or more broad parallel walls supported by intervening parallel spaced-apart longitudinal ribs, defining a series of hollow square tubes, may also be extruded or constructed to define a series of tubes of any desired shape.

19. The transparent, translucent, or opaque white or colored material of claim 12 wherein said material is applied by screenprinting adhesive sheet application or co- extrusion.

20. The backlight panel of claim 1, wherein said tubes may be cut, parallel to the longitudinal ribs on both sides of the lampholder sheet thereby allowing the lampholder sheet to curve in one or two dimensions.