NV Philips Gloeilampenfabrieken and Philips Lighting Pty Limited v Mirabella International Pty Limited [1993] FCA 404;

NV Philips Gloeilampenfabrieken and Philips Lighting Pty Limited v Mirabella International Pty Limited [1993] FCA 404; - FCA 1993 case summary — Zoe

[47]

"During the investigations which led to the

invention, it was found that an efficient

conversion of the electric power into ultra-violet

radiation is possible in a highly loaded

lamp. It was surprisingly found that the

efficiency of this conversion can be

substantially equal to that of the normal

40W/T12 lamp. It was found to be a prerequisite

that the electron temperature in the highly

loaded lamp assumes a value which is not lower,

and is, preferably higher than that in the

normal lamp. Various measures are possible to

achieve this. Starting, for example, from the

normal lamp, the required high electron

temperature is maintained if the discharge tube

has a smaller diameter, while the electric power

supplied to the lamp is kept substantially

constant. Compared to the normal lamps, the

electric field strength is then higher, the lamp

current is lower and the wall load is higher

than in the normal lamps. Experiments showed

that said high efficiency of the conversion into

ultra-violet radiation can also be obtained with

very low diameters of the discharge tube (from

one to a few mm). Another measure which makes

it possible to maintain a high electron

temperature is to reduce the rare gas pressure

in the lamp whilst increasing the supplied

electric power. Compared to the normal lamps

the lamp current is then considerably greater

and the electric field strength is substantially

the same or is somewhat lower. The wall load in

these lamps is of course higher.

It was furthermore found that with an efficient

production of ultra-violet radiation in highly

loaded lamps, there is not only a high ultra-violet

radiation density at the wall but also

the share of the radiation having a wavelength

of 185 nm is relatively higher than in normal

lamps. This unexpectedly high ratio between the

185 nm radiation and the 254 nm radiation

combined with the increased density of the total

ultra-violet radiation produced results in the

185 nm-load of the wall of such lamps being

considerably higher than in normal lamps."

[107]

"7(1) For the purposes of this Act, an invention

is to be taken to be novel when compared with

the prior art base unless it is not novel in the

light of any one of the following kinds of

information, each of which must be considered separately:

(a) prior art information (other than that

mentioned in paragraph (c)) made publicly

available in a single document or through

doing a single act;

(b) prior art information (other than that

mentioned in paragraph (c)) made publicly

available in 2 or more related documents,

or through doing 2 or more related acts,

if the relationship between the documents

or acts is such that a person skilled in

the relevant art in the patent area would

treat them as a single source of that information;

(c) prior art information contained in a

single specification of the kind mentioned

in subparagraph (b)(ii) of the definition

of 'prior art base' in Schedule 1.

(2) For the purposes of this Act, an invention

is to be taken to involve an inventive step when

compared with the prior art base unless the

invention would have been obvious to a person

skilled in the relevant art in the light of the

common general knowledge as it existed in the

patent area before the priority date of the

relevant claim, whether that knowledge is

considered separately or together with either of

the kinds of information mentioned in subsection

(3), each of which must be considered separately.

(3) For the purposes of subsection 92), the

kinds of information are:

(a) prior art information made publicly

available in a single document or through

doing a single act; and

(b) prior art information made publicly

available in 2 or more related documents,

or through doing 2 or more related acts,

if the relationship between the documents

or acts is such that a person skilled in

the relevant art in the patent area would

treat them as a single source of that information;

being information that the skilled person

mentioned in subsection (2) could, before the

priority date of the relevant claim, be

reasonably expected to have ascertained,

understood and regarded as relevant to work in

the relevant art in the patent area."

[192]

4. It would be very odd if Parliament, having carefully set the parameters for a determination of the questions of novelty and obviousness (see s. 18(1)(b) and s. 7), intended either to provide for an unfettered determination of the same issues by virtue of the use of the word "new" in the definition of "invention", or to provide for a duplication, by virtue of that definition, of the very questions of novelty and obviousness as set by the statute. But it does not follow that the question of new manufacture is excluded from s. 18. That is because an interpretation is open which, without evading or duplicating the statutory provisions in respect of novelty and obviousness, allows meaning to be given to the expression "manner of new manufacture". That this was the intention seems to me to follow, not only from the language of s. 18 read in the light of the definition of "invention", but also from a consideration of the structure of the Act as a whole, in the light of the history of the development of patent law, and of the explanatory memorandum and the report of the Industrial Property Advisory Committee of 1984 entitled "Patents, Innovation and Competition in Australia", to which the explanatory memorandum informs us the Act was a response. Under the heading "Manner of Manufacture", the Committee pointed out that the concept of s. 6 of the Statute of Monopolies involved three primary tests: "The invention must be new, inventive (not obvious), and capable of industrial application." The Committee went on to draw attention to the fact that under the existing law (the 1952 Act), as was in fact to be the position under the 1990 Act, the requirements of novelty and invention were the subject of express grounds of invalidity, while "the industrial capability requirement" arose from the reference to s. 6 of the Statute of Monopolies and the words "manner of ... manufacture". The Committee commented: "This concept involves little more than that an invention must belong to the useful arts rather than the fine arts." It added:

[203]

"The invention relates to a low-pressure mercury vapour

discharge lamp having a vacuum-tight radiation-permeable

envelope provided with a luminescent layer, a gas filling

comprising mercury and a rare gas, and means for

maintaining a column discharge in the gas filling, the

power consumed by the column being at least 500 W/m2

surface area of the luminescent layer.

Low-pressure mercury vapour discharge lamps are

radiation sources which are used on a very large scale both

for general illumination and for special purposes (for

example, activating photochemical processes), because they

convert the electric power supplied very efficiently into

radiation. In general these lamps consist of a tubular

envelop which may be straight or curved, for example in the

form of a circle or U-shaped. This envelope contains a gas

mixture comprising mercury and one or more rare gases in

which a column discharge is produced. This column

discharge is maintained by supplying electric energy to the

gas mixture, usually through two electrodes. Mainly

ultra-violet radiation is produced in the discharge, a

comparatively small part of which radiation has wavelengths

of approximately 185 nm, the greatest part of the radiation

having wavelengths of approximately 254 nm. This

ultra-violet radiation is converted by means of a luminescent

layer located on the inner wall of the lamp envelope, into

radiation having a longer wavelength and a spectral

distribution, depending on the luminescent material used,

in the near ultra-violet or in the visible part of the

spectrum.

One of the commonest types of low-pressure mercury

vapour discharge lamp is the so-called 40 W/T12-lamp

consisting of a straight tube which has a length of

approximately 1.20 (meters) and an internal diameter of

approximately 37 mm, and consuming a power of approximately

40 W. In general this lamp is operated with a lamp current

of approximately 400 mA and an electric field strength in

the column of approximately 80 V/m. The temperature of the

coldest spot of the envelope of such a lamp which is

free-burning in air is, in these circumstances approximately

40 degrees, at which temperature there is a mercury vapour

pressure of approximately 6x10-3 torr in the lamp. It

appeared that these circumstances are substantially optimal

as regards the production of ultra-violet radiation. Other

frequently occurring lamp types have in operation lamp

current, electric field and mercury vapour pressure values

which correspond to the above-mentioned values or do not

deviate much therefrom. The wall load of these lamps, that

is to say the power input of the column per surface unit of

the luminescent layer, has a value of approximately 300

W/m2 in these lamps.

Low-pressure mercury vapour discharge lamps have

already been made, wherein a considerably higher wall

load, namely 500 W/m2 is applied, so that the electric

power input per volume unit of the lamp becomes

considerably greater. This was done in the first place

with the object of obtaining small and compact lamps.

German Offenlegungsschrift 2,109,898, for example,

discloses small lamps having wall loads up to approximately

2500 W/m2. The electric field strength in these lamps is

higher than in the normal lamps and has, for example, a

value of the order of 600V/m. In the second place, the use

of high current densities (from 0.5 to 25 A/cm2) enabled

the production of lamps whose wall is loaded very highly.

These lamps are, for example, disclosed in United States

Patent Specifications 3,778,662 and 3,679,928. Wall loads

of the order of 25,000 W/m2 may occur in these lamps.

A great drawback of the prior art lamps with a

relatively high wall load is that the efficiency of the

lamp, that is to say the radiant flux or luminous flux of

the useful radiation emitted by the luminescent layer (the

output of useful radiation per unit of electric power

applied to the lamp) appears to have a low value. In

particular this efficiency is considerably lower than that

of the normal lamp (for example the 40 W/T12-lamp). This

drawback is especially felt with the compact lamps and is

one of the reasons that this lamp type, which might offer

great advantages for practical applications, for example as

a substitute for normal incandescent lamps, has as yet not

been introduced. The reason why it appeared to be

impossible to produce lamps having a high power input per

unit volume and with an efficiency comparable to that of

the normal lamps was not understood. Also known insights

as regards the optimum mercury vapour pressure (which

appears to be higher for lamps which are loaded to a

greater extent, for example to 0.75 Torr at a temperature

of the coldest spot of the lamp of 120 degrees C) and means for

controlling the mercury vapour pressure (amalgams etc) did

not lead to the desired result. It has, therefore, been

considered that producing a compact lamp, for example by

reducing the diameter whilst maintaining the electric power

supplied must inevitably be accompanied by loss in

efficiency.

The invention has for its object to provide low-pressure

mercury vapour discharge lamps which in operation

has (have) a high density of the consumed power and a high

radiation efficiency, so that on the one hand compact lamps

with an efficiency substantially equal to that of the

normal low-pressure mercury vapour discharge lamps and, on

the other hand, lamps having high current densities with an

improved radiation efficiency become available.

The invention provides a low-pressure mercury vapour

discharge lamp having a vacuum-tight radiation-permeable

envelope bearing a luminescent layer and containing a gas

filling comprising mercury and a rare gas, and means for

maintaining a column discharge in the gas filling, the

power consumed during operation of the lamp by the column

discharge being at least 500 W/m2 of the surface area

of the luminescent layer, wherein the luminescent layer

comprises a luminescent material which has the property of

having at 254 nm excitation a luminous flux, which after

the material has been subjected for 15 minutes to

ultra-violet radiation consisting substantially of the

wavelengths 185 and 254 nm, having a radiating density

between 150 and 500 W/m2 and having a ratio of 185 nm power

to 254 nm power between 0.20 and 0.40, is not more than 5%

lower than the initial luminous flux of the material at 254

nm excitation and measured in identical circumstances, and

wherein the combination of cations (as hereinafter defined)

in the luminescent material has an electronegativity of not

more than 1.4.

During the investigations which led to the invention,

it was found that an efficient conversion of the electric

power into ultra-violet radiation is possible in a highly

loaded lamp. It was surprisingly found that the efficiency

of this conversion can be substantially equal to that of

the normal 40W/T12 lamp. It was found to be a prerequisite

that the electron temperature in the highly loaded lamp

assumes a value which is not lower, and is, preferably

higher than that in the normal lamp. Various measures are

possible to achieve this. Starting, for example, from the

normal lamp, the required high electron temperature is

maintained if the discharge tube has a smaller diameter,

while the electric power supplied to the lamp is kept

substantially constant. Compared to the normal lamps, the

electric field strength is then higher, the lamp current is

lower and the wall load is higher than in the normal lamps.

Experiments showed that said high efficiency of the

conversion into ultra-violet radiation can also be obtained

with very low diameters of the discharge tube (from one to

a few mm). Another measure which makes it possible to

maintain a high electron temperature is to reduce the rare

gas pressure in the lamp whilst increasing the supplied

electric power. Compared to the normal lamps the lamp

current is then considerably greater and the electric field

strength is substantially the same or is somewhat lower.

The wall load in these lamps is of course higher.

It was furthermore found that with an efficient

production of ultra-violet radiation in highly loaded

lamps, there is not only a high ultra-violet radiation

density at the wall but also the share of the radiation

having a wavelength of 185 nm is relatively higher than in

normal lamps. This unexpectedly high ratio between the 185

nm radiation and the 254 nm radiation combined with the

increased density of the total ultra-violet radiation

produced results in the 185 nm-load of the wall of such

lamps being considerably higher than in normal lamps.

The invention is based on the recognition that

failure of the prior art lamps with high wall load is not

due to a low efficiency of the conversion into ultra-violet

radiation, as has been generally assumed so far, but is due

to the luminescent materials used. The invention provides

suitable luminescent materials as a measure for obtaining

efficient, highly loaded lamps. Consequently, the present

invention opens the way to an entirely new lamp type,

namely the compact low-pressure mercury vapour discharge

lamp which can replace the normal incandescent lamp which

is used in very great numbers. As the efficiency of the

low-pressure mercury vapour discharge lamp is approximately

5 times greater than that of the incandescent lamp, a very

considerable saving in energy is possible. In a lamp

according to the invention a luminescent material is used

which is, on the one hand, highly resistant against 185 nm

radiation, that is to say it has only a very slight

decrease in the luminous flux (on excitation by 254 nm

radiation) owing to irradiation by 185 nm rays and which,

on the other hand, has a high mercury resistance.

It is known that subjecting a luminescent material to

185 nm radiation has in general even after a very short

period of time a detrimental effect on the luminous flux of

the luminescent material. As a measure of the resistance

to 185 nm radiation the so-called short term decrease is

used, which in this description is understood to mean the

decrease (in %) in the luminous flux of the material, when

excited by 254 nm radiation) (sic) as the result of an

irradiation for fifteen minutes by radiation having wave

lengths of mainly 185 nm and 254 nm with a radiation

density between 150 and 500 W/m2 and with a ratio of 185 nm

power to 254 nm- power between 0.20 and 0.40. An

arrangement for determining the short term decrease as well

as the value of this decrease for some luminescent

materials is known from "Illuminating Engineering" 59

(1964), pages 59-66. Such an arrangement will be described

in greater detail below. Owing to the high density of 185

nm radiation, high requirements are imposed in lamps

according to the invention on the short term decrease of

the luminescent material. This decrease shall not be more

than 5%. It has been found that for a higher value of this

decrease, lamps are obtained which furnish an unacceptably

low luminous flux after having burned for the few minutes

which are required for obtaining a steadily burning lamp;

in practice the short term decrease has already taken place

when the luminous flux of the lamp is measured at 0 hour.

In a lamp according to the invention the luminescent

material must not only satisfy the requirement as regards

the short term decrease but also the requirement for a

higher degree of mercury resistance. It has, namely, been

found that the luminous layer in highly loaded lamps is

exposed to a much greater number of collisions with excited

mercury atoms and mercury ions than is the case in normal

lamps. The highly energetic mercury atoms and ions can be

absorbed at the surface of the luminescent layer and/or

react with the luminescent material. Consequently a

darkening of the luminescent layer occurs which

considerably reduces the luminous flux of the lamp. A

measure of the mercury resistance of a luminescent material

is found in the electro-negativity (e.n.) of the cations of

the luminescent material. In this description and the

claims, cations is defined to mean the metals from the

series 1A, 1B, 2A, 2B and 3B of the periodic system of

elements as specified in "Handbook of Chemistry and

Physics", Cleveland (Ohio). The further elements are here

considered as anions or anion-forming elements. The values

of the electronegativity (e.n.) of the elements are given

in L. Pauling "The Nature of the Chemical Bond", New York

(1945). If the elements are arranged in a series on the

basis of an increasing value of the e.n. the so-called

electromotive series of the elements is obtained. In

principle a certain element can displace all elements from

this series having the same or a higher value for the e.n.

from a compound. It is now clear that mercury (which has

an electronegativity of 1.9) will attack luminescent

materials whose cation has e.n.>- 1.9 (these cations are

equally noble or nobler than mercury). It was (has) now

been found that the cation of a luminescent material

suitable for lamps according to the invention must have a

relatively low e.n., namely not more than 1.4. This can be

explained from the fact that the mercury in the discharge

plasma is richer in energy than neutral mercury and from

the fact that the number of times the mercury collides with

the luminescent layer is high. It was found, for example,

that a luminescent material containing zinc (e.n. = 1.6) as

a cation, which in normal lamps shows some mercury attack

only after a relatively long operating period can

definitely not be used in highly-loaded lamps because the

luminescent layer is already markedly darkened after the

lamp has burnt for a period of from some minutes to some

hours. If a luminescent material contains several cations,

for example if the element used as an activator is a

cation, the combination of cations should have an e.n. of

not more than 1.4, which in the description and claims is

defined to mean, the weighted average of the

electronegativities of the cations shall not be more than

1.4. In that case it is possible that a small part of the

cations in the luminescent material per se has for itself

an e.n. higher than 1.4.

Preference is given to low-pressure mercury vapour

discharge lamps according to the invention containing a

luminescent material which has the property that it

furnishes, after the above-described ultra-violet

irradiation for 15 minutes, a luminous flux which is not

more than 3% smaller than the initial luminous flux.

Luminescent materials which have such a low short term

decrease result in lamps having a very high luminous flux,

also with very high wall loads.

In lamps according to the invention an electric field

strength of 150 to 1000 V/m is preferably maintained in the

column discharge during operation. This relatively high

field strength can be obtained by using an envelope having

a relatively small diameter. With a relatively low lamp

current, compact, highly loaded lamps having a high

luminous flux are then obtained."

[233]

20. (There is a quite independent importance to be attached to this evidence of Dr Lowke. The appellant relied on the commercial success of the invention, which is relevant to novelty as well as to obviousness, and therefore to whether there is a manner of new manufacture (see Fox, The Canadian Law and Practice relating to Letters Patent for Inventions, 4th ed. (1969) 73 et seq., 102). But the learned trial judge, in a passage I shall quote, discounted that success as due to "the higher cost of electricity, making (the invention's) energy-efficiency more important to consumers". With respect, the observation does not meet the point. Westinghouse, as well as Philips, thought a compact lamp desirable, and they thought so in the period before the priority date, when higher energy costs had already affected the entire industrial world, and their continuance was, in actual fact, perhaps more feared than subsequent economic history has justified. Events of such notoriety are a fit subject of judicial notice, but in any case, there was evidence that "(t)he 1973 oil crisis set off unprecedented demand for energy efficient appliances, of which lighting products were an important part". That was four years before the priority date. The appellants' point - which the authorities support - is that their own success in solving a problem which was recognized by others; awaited solution for several years; and could be seen to be blocking a potentially profitable development, tends to confirm that what they achieved was an invention. The force of such an argument always depends upon showing that there was reason for others to try to do, or that others have in fact been shown to have tried to do, what only the patentee achieved. The inference is then that the invention is no mere analogous use of a well known thing, nor was the advance made an obvious one. See The General Tire and Rubber Company v. The Firestone Tyre and Rubber Company Limited (1972) RPC 457 at 503; Allsop Inc v. Bintang Ltd [1989] FCA 297; (1989) 15 IPR 686 at 702-703. Here, Dr Lowke's evidence shows Westinghouse discussed making a compact fluorescent lamp, only to accept that it could not; and the invention, when made, had the commercial success which had been anticipated for it.)

[249]

"I think everyone would agree that, if a person discovered a

new property in a known material which, for the first time,

made it apparent that the material was suitable for a new

use, the discovery would amount to an invention and the

claim of the patent would be for a manner of new

manufacture. But that is not this case. The present

patent does not claim the discovery by the patentees of any

new property of phosphors, making them suitable for use in

highly loaded low-pressure mercury vapour discharge lamps.

The luminescent qualities of phosphors had long been known.

. . .

The contribution to the art claimed by the patentees -

in relation to Claims 1 to 5, the only contribution they

claim - is to specify desirable STD and e.n limits for

phosphors used in highly loaded lamps. They make no claim

that a phosphor whose STD or e.n exceeds one or both of

those limits will be unsuitable for use in a highly-loaded

lamp; it is just that the lamp will be less efficient than

a conventional fluorescent lamp and, presumably, less

competitive with incandescent lamps. Neither the patent

nor the evidence suggests that the STD and e.n values

stipulated in the patent reflect any discovery or new

scientific insight by the patentees; rather they were

figures chosen to reflect the patentees' judgment as to the

degree of efficiency-loss from these two causes which would

be commercially acceptable. No doubt the choices were

carefully calculated, and I do not doubt that phosphors

meeting those parameters have enabled Philips to market a

successful product; but the stipulated figures are

arbitrary, in the non-pejorative sense of depending upon

the will or discretion of the patentees.

During the course of their oral submissions, counsel

for the applicants described Claim 1 as 'a statement of the

criteria to be met by manufacturers to achieve a vendible

product. The patent tells people how to make the lamp.

They know about phosphors but this tells them in two

important respects'; that is, STD and e.n. In support of

that position, counsel pointed to evidence establishing

that, since the priority date, compact highly-loaded lamps

have begun to be manufactured and, especially in recent

years, have sold in significant numbers.

There is no doubt about the increasing use of compact

highly-loaded lamps. There is some dispute as to its

cause. There is evidence that a major factor in the

growing popularity of compact lamps is the higher cost of

electricity, making their energy-efficiency more important

to purchasers. But, be that as it may and accepting the

success of the Philips product, it seems to me that it is

not an invention, or a manner of new manufacture, for

someone to specify the criteria required to be met, in the

manufacture of a known product from known materials, in

order to achieve vendibility. As was said by Dixon CJ,

Kitto and Windeyer JJ in National Research Development

Corporation v Commissioner of Patents [1959] HCA 67; (1959) 102 CLR 252 at

262: 'Unless invention is found in some new method of using

the material or some new adaptation of it so as to serve

the new purpose, no valid patent can be granted'."

At a glance

Court

Decision date

Before

Source

Judgment (272 paragraphs)

NV Philips Gloeilampenfabrieken and Philips Lighting Pty Limited v Mirabella International Pty Limited [1993] FCA 404; (1993) Aipc 91-025 (1993) 117 ALR 79 (1993) 44 FCR 239 (26 August 1993)

Parties

Legislation Cited (2)

Cases Cited (22)