JPH09504638A - Improvements in or related to backlighting - Google Patents

Abstract

(57) [Summary] The backlight device comprises a discharge lamp envelope (10) and a spirally formed induction winding (2), and the winding is formed of a single layer. The electromagnetic field produced when an alternating voltage is applied to the winding (2) couples inside the envelope (10) in which a plasma arc is produced.

Description

Detailed Description of the Invention Improvements in or related to backlighting   The present invention is directed to backlighting, especially for liquid crystal displays (LCDs). It is related to backlighting, but is not limited to these.   Widely competitive cathode ray tube (CRT) technology that has been demonstrated for much longer One of the main advantages of LCD technology compared to Due to its compactness, LCD is the only LCD in some display applications. It may be a profitable solution. Due to its bulkiness, CRTs for aesthetic reasons There are many other fields of use that have become undesirable.   CRTs effectively also include their own light source, while LCDs require external lighting. I do. Sometimes this can be provided by ambient lighting, where the LCD is inherently reflective. With. However, more often LCDs are backlit. Is required, and the backlighting technology is It is essential that the compactness is not unduly compromised. Back lighting is the same In addition, it has a substantially uniform brightness, is economical in its power consumption, and is acceptable. It must indicate the life expectancy.   Thus, there is a great deal of interest in developing efficient and compact backlights for LCDs. Significant efforts have been made to make good backlights that include fluorescent tubes and diffusers. Well known. Further proposals for improved devices are given, for example, in JP-A-63150850, J Published in P-A-63208543, JP-A-62150647 and US-A-4,872,741.   All of the above publications are relatively thin bags that utilize electrodeless lamp technology. Discloses Crite. JP-A-63150850 and JP-A-63208543 are common housings. Discloses the use of multiple tubular electrodeless lamps within a ring. On the other hand JP-A-62150647 And US-A-4872741 use an electrodeless lamp containing a single flat envelope. Is disclosed.   Delivers a light output with excellent uniformity and high brightness, yet exhibits a long service life Since it has the potential for compactness in the thickness dimension, It is clearly desirable to use electrodeless technology for backlighting.   However, the electrodeless lamp must be excited for it to operate. Not containing a gas filling material, and the radio frequency It is necessary to apply a number (RF) energy to the excitation element and couple it into the gas-filled material. There is a problem in that it is important. The efficiency of such coupling is Very important when you need to operate with high reliability and high brightness It is. The present invention is mainly related to electrodeless backlighting technology. On this side.   JP-A-62150647 is designed to place coupling elements around a rectangular electrodeless backlight. Is proposed. However, with this arrangement, relatively in the plane of the backlight. Exciting the lamp with the required evenness if it exceeds a small constant size You won't be able to On the other hand, US-A-4,872,741 covers the entire back surface of the rectangular backlight. It proposes to use an array of circularly distributed annular coils. However, this The placement creates a limitation in igniting the lamp and yet the overall thickness of the backlight. To the extent that the thickness of the annular coil is added to the measured size, Violate the sexuality. Moreover, there is a lack of control over the shape of the gas discharge produced. Furthermore, the uniformity performance tends to be limited.   According to the invention, in an electrodeless backlight for illuminating a display , Composed of two dimensions to fit the dimensions of the display, the third dimension Represents the thickness of the assembly and stimulates the conversion process to produce visible light itself. When radio frequency (RF) energy is added to produce electromagnetic radiation, it responds accordingly. Contains at least one envelope containing a gas-fillable material capable of responding A backlight including a substantially flat assembly for storing, comprising: Originally it has a spread, but in the third dimension, it is substantially only the thickness of the conductive material. Made of this conductive material that conforms to a predetermined pattern that extends about The RF energy to the gas-filled material, including one or more drive means Characterized by means for adding, said pattern being of a helical configuration as a whole Provided with electrodeless backlight, juxtaposed with the envelope .   In order to clearly understand the present invention and to carry out the present invention easily and effectively, reference will be made to the accompanying drawings. However, some embodiments are described by way of example only. In the figure,   FIG. 1 schematically represents a first embodiment of the invention.   FIG. 2 represents an alternative spirally formed winding.   FIG. 3 schematically shows the effect of an alternative winding on a plasma arc.   FIG. 4 schematically represents an alternative arrangement of spirally formed windings.   FIG. 5 schematically shows a circuit for driving a winding according to the invention.   FIG. 6 schematically represents a non-planar arrangement according to the invention.   FIG. 7 shows a spiral winding formed directly on the lamp envelope. The line is schematically represented.   FIGS. 8 (a), 8 (b) and 8 (c) each show a unique spiral electrode in single or multiple How do we get a large area display from a relatively small number of individual backlights Shows if a backlight for spraying can be built.   FIG. 9 shows a backlighting arrangement including mosaic processing of a hexagonal backlight. Represents a part.   10 and 11 show a standard structure of a circular backlight according to an embodiment of the present invention. It is a perspective view and a three-dimensional exploded view, respectively. or,   FIG. 12 shows a suitable circuit arrangement for the RF drive circuit.   Referring first to FIG. 1, an inductive winding 2 of a conductive material, in this case copper, is It can be seen that it is formed in a spiral shape on the board substrate 44. Circuit board 4 is initially the main At least one of the required surfaces has a copper coating, which is By standard lithographic techniques to create a spiral pattern on the body To be removed.   The circuit board 4 is in close proximity to the hermetically sealed glass envelope 10 containing the gas filling. To be made. The nature of the gas-filled material depends on the desired optics the backlight should produce. Typically, the envelope 10 has a reduced pressure (≈2 mbar) gas depending on its characteristics. Storm or inert gas is stored, and a small amount of mercury is also stored. Two of the envelopes One of the major surfaces of the That is, the front surface (facing the LCD) that is to be illuminated is the phosphor coating inside it. Have a ting. The circuit board 4 and the envelope 10 are indicated by the dashed line 12 in FIG. Are adjacent to each other, and thus the winding 2 is juxtaposed with the envelope 10. In case of a radio frequency (RF) from the voltage source (not shown) to the winding 2 via the contact 6.8. AC voltage is supplied. The spiral winding 2 is unidirectional as shown in the figure. The current induced in the gas-filled material is the non-cancelling current. It is very important to. This requirement will be readily apparent to one of ordinary skill in the art. . As is known, a plasma arc is initiated within envelope 10, which causes phosphorescence. It produces ultraviolet radiation having a wavelength that excites the quality to produce visible radiation. This In the same way, the backlight produces visible light which can then be used to illuminate the LCD. Can be.   Obviously, another major surface of envelope 10 (sub-table if desired) The surface as well) can be coated with a phosphor. Normally envelope 10 , Made of glass, in which case the phosphor coating (s) is / are , Suppose the glass absorbs UV radiation and thus the phosphor is outside the envelope. Since it would significantly reduce the efficiency of the device, Need to be However, a stone whose envelope 10 does not significantly absorb UV radiation Easier to perform than internal coating when made of materials such as English External phosphor coatings can be used.   In any of the arrangements described, the reflective material is otherwise Envelop any visible or UV radiation that leaks through the surface and is wasted On the rear surface of the envelope 10 or adjacent to this surface to reflect back into the chamber. Can be equipped. In the example of FIG. 1, the winding 2 is a single regular geometric spiral It is shown as being helically formed. Similarly, referring to FIG. , Alternative forms of helix formation for windings, each of which is a known non-helical form It offers different advantages over molded inductive windings. However, consistent profit The point is the ignition of the discharge (ie Start) is easier and It is about making it reliable. This is a whole spiral like this This is because the electric field generated by using the pattern is radiative.   FIG. 2 (a) shows a winding 2 formed in the same circular spiral shape as in FIG. On the other hand, FIG. 2B shows the winding 2 formed in an elliptical spiral shape, and FIG. 2) shows a rectangular winding, and FIG. 2D shows a multiple concentric winding. Thus, "spiral" and "spiral" as used throughout this document. Is intended to cover not only curves but also straight lines, non-uniformities and multiple helices. It will be clear that it is illustrated. However, each feature is The "radius" from a central reference point that keeps increasing with a complete loop or turn.   The shape of the winding 2 formed in a spiral shape has an arbitrary degree as shown in FIG. However, each shape is unique among the gas filling materials of envelope 10. To produce the characteristic plasma arc of. By referring to FIGS. 1, 2 and 3, Some of these features are exemplified below.   In each of FIGS. 3 (a), (b) and (c), the cross section ABCD of the envelope 10 is , In the direction of the arrow in Figure 1 so that the line CD bisects the envelope along the long side. Shown as seen. Each figure in FIG. 3 shows a gas charge for differently shaped windings. An example of plasma arc discharge in a filler is shown. Thus, the fruit in the cross section ABCD Line 13 is the contour of the electron density of the plasma arc.   FIG. 3 (a) shows an annular coil as proposed in US-A-4,872,741. 7 illustrates an uneven discharge generated. The coil has a circular shape, numbered 12 It is shown in cross section with the number.   In FIG. 3 (b), the cross-section 14 is shown in FIG. 2 (a). 3 is a cross section of the winding 2 formed in such a regular spiral shape. High in Figure 3 (b) The electron density contour 13 is more uniform around the envelope compared to that of FIG. It is understood that it is distributed in. This is due to the flat nature of the winding.   Similarly, the cross-section 16 of FIG. 3 (c) shows a spiral winding of FIG. 2 (d). The one on line 2. This is shown in Figure 3 as can be seen clearly by the contour shape. The most uniform electron density distribution and therefore the most uniform light output of all the winding arrangements Can provide power. However, in reality, the circular spiral arrangement of FIG. It is preferred to use either of the elliptical configurations of Figure 2 (b).   The spirally formed winding according to the invention is of a single layer, thus For example, it effectively provides a two-dimensional winding that occupies a smaller space than the annular winding. It is one of the features of the present invention that, as illustrated in FIG. It is also possible to stack and / or sandwich multiple layers.   FIG. 4 (a) illustrates a number of square spiral windings 18. On the other hand, FIG. 4 (b) illustrates a large number of hexagonal spirally formed windings. You. As discussed with particular reference to FIG. 3, each of these arrangements It will give the plasma arc in the oop 10 its own characteristics. Circular helix In FIG. 4 (c), which illustrates the windings formed in a strip shape, the windings 22 in the foreground are The winding 234 is formed on one side, and the winding 234 is formed on the other side of the circuit board 4.   Referring now to FIG. 5, a circuit suitable for driving a winding according to the present invention is generally shown. It is schematically illustrated. Winding 2 is via contact 6.8 and via capacitors 26 and 28 Coupled to the voltage generator 30. The voltage generator 30 generates an alternating voltage at 13.56MHz , The capacitor 26 is a 19pF Capacitor 28, while capacitor 28 is 54 pF. Winding 2 is a 2.5mH inductor Dimensioned (in a known manner) to have a closet.   The spirally wound winding according to the invention must be formed in a single layer However, as in the previous example, this layer needs to be flat and the envelope is flat There is no need at all. Naturally, an efficient coupling between the backlight and the winding For, the shape of the winding monolayer must match the shape of the backlight. No, so this layer may be appropriately curved or twisted. An example of this is As shown in FIG. 6, in this figure the same components as previously described Have the same number. In FIG. 6, the winding 2 is still a single layer on the circuit board 4. , The circuit board 4 is curved rather than flat as shown previously.   In the above example, the winding 2 is shown formed on the circuit board 4, It is adjacent to group 10 but separate. This does not have to be , Winding 2 over envelope 10 and envelope 10 as shown in FIG. It can also be formed in an integrated form. Thus, more than just the above A rim arrangement is obtained.   Those skilled in the art will appreciate that the spirally formed windings are uniform regardless of their shape. It turns out that you don't have to be forced to have a good turn spacing Would. The present invention thus utilizes a single layer spirally formed winding. A thinner back with a more even light output than previously known Aim to achieve the light.   It will also be appreciated by those skilled in the art that the spirally formed winding according to the present invention will be conductive. Always empty between each successive turn or loop of the member It will also be apparent that there will be gaps or intervals. This void or space Separation may be electrically isolated, for example, by leaving a void between each loop or on a conductive member. Coat the material and then wrap this amalgam in a spiral around itself Can be achieved by   Back for relatively large area displays (eg 9 "x 8") When manufacturing lights, multiple lights, each with its own single or multiple biasing electrodes It is appropriate to build this up from a smaller backlight. For example, 6 ″ × The 8 ″ backlight is shown in FIGS. 8 (a), 8 (b) and 8 (c), respectively. Driven by one, two or three spiral electrodes and arranged side by side It can be made up of four 6 ″ × 2 ″ envelopes placed.   Obviously, the envelope does not have to be rectangular, even if it is rectangular, the figure There is no need to conform to the configurations shown in 8 (a), 8 (b) and 8 (c). Yes. For example, eight 3 "x2" rather than four 6 "x2" envelopes. Manufacturing a backlight for a 6 "x 8" display from an envelope. Are considered to be preferred and the configuration of the spiral electrodes may be correspondingly different. However, in general, the joints or butt lines between the various envelopes are Can cause non-uniformity in light output, and are discussed in this and the previous section. Number of individual envelopes used to make a composite backlight of a given type Is preferably minimized. This is a diffuser or microphone if desired Compensation can be done using various optical components such as the Rollens array, but additional It is cheaper and easier to manufacture a composite backlight without components.   It consists of mosaic processing of each hexagonal envelope that creates a honeycomb-like structure. The composite backlight allows the nonlinearity of light output to be received over the entire surface area of the display. The regular and non-linear butt lines are distributed so that they are distributed in an acceptable manner. This is a particularly suitable configuration in that Such an arrangement is shown schematically in FIG. ing.   In all embodiments, a copper layer class is deposited on a non-conductive substrate such as a printed circuit board. It is appropriate to manufacture the spiral electrode by etching through the pad But this is not essential. Copper thickness is typically 30-60 microns And the etching is performed according to standard photolithographic procedures. Spiral electrodes It is typically driven at 13.56MHz and receives about 20 watts of power, so Must be able to withstand significant heating,   It may be preferable to use a ceramic substrate under certain circumstances. Generation Alternatively, as described above, one or more helical electrodes can be directly attached to the surface of the envelope itself. A pole can be formed and this envelope is typically made of glass or quartz. Will be done.   As can be seen from FIG. 5, in this case, the capacitor is the inductor of the spiral electrode. Used to tune the circuit in the chest. These capacitors are especially double-sided. Occupied by single or multiple electrodes when using a copper clad substrate Be formed in an unused area of the copper cladding away from the area being Is appropriate. In that case, the overlapping areas of the copper cladding on opposite sides of the board Can be left in place to create a capacitor. In any case It is also appropriate to provide fine tuning capabilities, which can be Trimming of appropriately positioned movable interposer elements in relation to several or more electrodes It can take the form of a capacitor.   Figure 10 shows a standard construction for a circular backlight unit with a diameter of 70 mm. Which basically houses the lowered cylindrical backlight envelope 36. A main housing 34 is included. It is easier to see the three-dimensional exploded view of Fig. 11. As such, components 34 and 36 have, to the rear, a spiral wire of the kind described above. Pole 38, DC to RF converter and matched power drive circuit 40 in main housing 34 Is supplemented. Further, the rear tightening plate 42 and the unit back component 44, Front clamping plate 46 neoprene cushioning shims 48, transparent protection on the front of the unit Various positions such as screen 50 and envelope holding plate 52 There are constant and protective components. In front of the main housing 34 A numbering plate 54 is also attached. The DC power is Applied via circuit 56 and connected to circuit 40.   Figure 12 shows a 13.56MHz, 20 Watt drive for the spiral electrode as described above. 2 shows a suitable circuit layout for the power supply of the power supply.   This circuit arrangement is compatible with the circular lamp (not shown) previously described in connection with FIGS. Will be stored in a die-cast box (not shown) designed for use with Is intended. This includes DC up to 30 volts with a current capacity of 1.25 amps Power is needed. Heat sink fixed on the outside of the box allows continuous operation I'm working.   The circuit has a crystal controlled oscillator 58 that drives a single-ended amplifier 60. This amplifier , Class E with 50 ohm load impedance if 80% DC-RF efficiency is obtained Designed to work with. When driven with other impedance , Lower efficiency may be obtained.   Two FETs 62 and 64 in the circuit, one 2N7000 (62) in the oscillator Also, one IRF510 (64) is used as the output amplifier. Initial bus for 2N7000 Ias is provided by a 1M / 100K ohm voltage divider 66, 68 that provides the gate voltage. Provided. Once started, start to reduce power supply if necessary Approximately 25 supply voltages are required to initiate the bias overriding oscillation. Is done. Feedback to maintain oscillation is provided between the drain gate of FET62. Supplied with a 4K7 resistor 70 and a 13.56MHz crystal 72. Position of feedback signal The phase is optimized with a 33pF capacitor 74 connected to ground. In this stage The tuned load for this is a 0.68uH inductor 76, a 220pF capacitor 78 and a FET6. Offered by 4 gate capacities.   For the required output, a load impedance of about 10 ohms is needed, so A low frequency "L" cross-section impedance transformer is included. The series inductor of this transformer The closet, combined with the series inductor of the output network, provides a single component I have. This inductor is variably made to allow for circuit adjustments and tolerances. I have.   10nF from power supply to capacitor 80 and 100nF capacitor 82 to ground The feed reduces the RF guided along the supply line.   Class E circuits are simple and efficient, but provide high voltage to the transistor. impose. The peak current is almost three times the average, and the peak voltage is more than three times the power supply. is there. If 100 volt transistors are used, the maximum supply is 30 volt Should be restricted.   To complement, the values of the remaining components illustrated in Figure 12 are: .   Resistor 84 ... 1M   Resistor 86… 100K   Resistor 88… 120   Capacitor 90… 4n7   Resistor 92… 1K   Inductor 94… 4μH   Capacitor 96… 150p   Capacitor 98… 470p   Inductor 100… 0.6μH variable   Capacitor 102… 180p   Capacitor 104… 330p   Another improvement useful in situations where very high brightness and lighting uniformity are required Will be described next. In this case, the front phosphor coating (ie , On the main surface of the backlight facing the display). this The layer is thick enough to excessively absorb the forward visible light produced by the actual phosphor. Although not essential, it does provide effective conversion of forward UV radiation from the discharge into visible light. Manufacture is particularly difficult because it must have a sufficient thickness to be traced You.   In practice, achieving both of these goals together is very difficult and Too thin to completely convert all UV light reaching the surface phosphor into visible radiation One compromise must be reached involving the use of phosphors. Ultimately This means that the backlight has its full potential in terms of brightness or evenness. It can mean that you do not achieve power. Plus, a thick rear phosphor Producing envelopes with thin front phosphors of good quality and well-controlled results Significant manufacturing concerns when glass envelopes with internal phosphors should be used Problems result.   These problems are in the rear part of the envelope, Only a single phosphor layer, which can be any of the If so, it can be overcome or reduced. This phosphor is forward (ie Enough to ensure maximal production of visible radiation (towards the display) It has thickness. Adjacent to the front of the envelope (which must be UV transparent) Installed a dichroic mirror, which is located in the visible part of the spectrum. Transmits radiation (wavelength> 400 nm) and emits radiation in the UV portion of the spectrum (wavelength <400 nm, However, mainly the main UV line near 254 nm generated in low-pressure mercury discharge) Has the property of reflecting. This results in forward penetration from the backlight with minimal attenuation. Both directly from the plasma being exposed and from the rear surface phosphor The useful visible radiation produced will be obtained. However, from the plasma Forward UV radiation is reflected back towards the plasma, where it again Absorbed in or propagated in the plasma to aid irradiation of the rear surface phosphor. I can. In this way, most of the forward UV radiation from the plasma is discharged plasma. By optically pumping the laser (therefore the RF required to drive the discharge) Visible radiation produced by reducing the power) or from the rear phosphor Will be utilized by increasing the amount of. On a part of the spectrum Very high transmission and high reflectance in the other part of the spectrum Dichroic mirrors with the required properties are currently available.

[Procedure of Amendment] Article 184-8 of the Patent Act [Submission date] September 12, 1995 [Correction contents]                         The scope of the claims   1. An electrodeless backlight device for illuminating a display, the device comprising: It consists of two dimensions to fit the dimensions of the spray device, the third dimension being the The electrical field that represents the thickness of the shell and in turn stimulates the conversion process to produce visible light. Capable of responding to the application of radio frequency (RF) energy to produce magnetic radiation A real built-in at least one envelope part (10, 36) containing a gas filling part A backlight device with a qualitatively flat assembly, wherein the envelope part It has a spread in the two dimensions, but in the third dimension it is Conductivity that conforms to a predetermined pattern that extends substantially only in thickness The radio frequency energy provided with one or more driving means made of a conductive material (2, 38) Is a means for applying a ghee to the gas-filled portion, and the pattern described above In the above pattern, the conductive material has a tubular structure and Formed on substrates placed in parallel and in close proximity, and the substrates are substantially Either flat or equiangular to the envelope. An electrodeless backlight device for display illumination, which is characterized in that   2. An electrodeless backlight device for illuminating a display, the device comprising: It consists of two dimensions to fit the dimensions of the spray device, the third dimension being the The electrical field that represents the thickness of the shell and in turn stimulates the conversion process to produce visible light. Capable of responding to the application of radio frequency (RF) energy to produce magnetic radiation At least one envelope part (10, 36) for accommodating a gas filling part A backlight device having a substantially flat assembly, the envelope portion comprising: Has a spread in the two dimensions, but the third In the dimension of the Driving means or means consisting of a conductive material (2,38) adapted to the patterned pattern Is a means for applying the radio frequency energy to the gas filling part, The upper pattern generally has a spiral structure, and the conductive material is used in the above pattern. Material is formed on the envelope, electrodeless backlight device .   3. The envelope is made of glass, extends in the two dimensions, and Carrying an internal phosphor coating on its at least one surface facing the display The backlight device according to any one of claims 1 and 2, which is .   4. The envelope is made of a UV transparent material and extends in the two dimensions. And an outer phosphor coating on at least one surface of the display facing the display. The bag according to any one of claims 1 and 2, which supports the bag. Light device.   5. The predetermined generally spiral pattern accommodates a substantially circular configuration A backlight device according to any of the preceding claims, which is   6. The predetermined generally spiral pattern is adapted to a substantially elliptical configuration. What is claimed is in any one of Claim 1, Claim 2, Claim 3, or Claim 4. Backlight device.   7. The predetermined generally spiral pattern accommodates a substantially rectangular configuration Claims 1, 2, 3 or 4 according to any one of claims Backlight device.   8. The predetermined generally spiral pattern is a half between its successive turns. The preceding claim containing at least one irregularity in the radial spacing. Backlight device described in any of the ranges Place.   9. The conductive material is in the range of 30 microns to 60 microns Backlight according to any one of the preceding claims, which is copper having a thickness. Device.   Ten. The copper comprises a clad laminate to a non-metallic substrate, A backlight device according to claim 9.   11. Used to apply the radio frequency (RF) energy to the drive means At least one capacitor is formed by a portion of said copper clad laminate 11. The backlight device according to claim 10, which is a device.   12． Assembly of a plurality of backlights according to any one of the preceding claims A backlight device including a brim (assembly unit).   13. Each backlight in the assembly has a hexagonal envelope 13. The device according to claim 12, which is

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Claims (1)

[Claims]   1. An electrodeless backlight for illuminating a display, It is composed of two dimensions to fit the dimensions of B, and the third dimension is the thickness of the assembly. Produces electromagnetic radiation that manifests itself and stimulates the transmutation action to produce visible light Responds to when radio frequency (RF) energy is applied to it Contains at least one envelope that contains a removable gas filling A backlight with a substantially flat assembly, the backlight comprising: However, in the third dimension, substantially only the thickness of the conductive material is concerned. A single piece of this conductive material that conforms to a pre-determined, spreading pattern Or applying the RF energy to the gas-filled material, including a plurality of drive means Characterized in that the pattern has an overall helical configuration An electrodeless backlight that is parallel to the bellows.   2. The envelope is made of glass and extends into the two dimensions. An internal phosphor coating on at least one surface facing the spray The backlight according to claim 1, which is supported.   3. The envelope is made of UV transparent material and extends in the two dimensions An external phosphor coating on at least one surface of the display facing the display The backlight according to claim 1, which supports the lighting.   4. The predetermined generally spiral pattern is in a substantially circular configuration. A backlight according to any one of claims 1 to 3, which is adapted. .   5. The predetermined overall spiral pattern is substantially elliptical. Any one of claims 1, 2 or 3 adapted to a circular configuration Backlight described.   6. The predetermined generally spiral pattern is suitable for a substantially rectangular configuration. The buckler according to any one of claims 1, 2, and 3 which are in conformity with each other. Ito.   7. The predetermined overall spiral pattern is its continuous turn. Claim 1 including at least one irregularity in the radial spacing between ~ The backlight according to any one of items 6.   8. The conductive material is copper with a thickness in the range of 30 to 60 microns The backlight according to any one of claims 1 to 7.   9. The copper includes cladding on a non-metallic substrate. The backlight according to item 8.   Ten. At least used to apply the RF energy to the drive means Another capacitor is formed by a portion of the copper cladding The backlight according to claim 9.   11. The backlight assembly according to any one of claims 1 to 10. Backlight device including   12． Each backlight in the assembly includes a hexagonal envelope Apparatus according to clause 11 of the.