WO1994001854A1

WO1994001854A1 - Method for creating objects, which emit light in a homogeneous and isotropic way by means of their vast surfaces with a low voltage supply, objects resulting from this method and their uses

Info

Publication number: WO1994001854A1
Application number: PCT/GR1993/000012
Authority: WO
Inventors: Christophoros Vasiliou
Original assignee: Christophoros Vasiliou
Priority date: 1992-07-10
Filing date: 1993-07-09
Publication date: 1994-01-20
Also published as: AU4512293A; GR1001279B

Abstract

This invention relates to a method which arranges rows of photodiodes opposite to reflecting surfaces and fills the space between them with a semitransparent material being solidified offering its external surface, properly formed, as an emitting surface of the object, when the proper voltage is applied to the row of photodiodes. The objects produced by means of this method can have, in proportion to our specifications, a large or small enough size and a low voltage supply from 1,5 V to 24 V DC, depending on the capability of the use each time. The uses of these objects extend from the domain of construction of jewels, rosettes, toys and small decorative things to the most bulky decorative articles and the illuminated digital panels.

Description

SPECIFICATION

"Method for creating objects, which emit light in a homogengous and isotrogic way by means of their vast surfaces witha low voltage supply, objects resulting from this method and their uses."

The present invention relates to a method for creating objects, which include a row of powerful photodiodes, reflecting surfaces and a semitransparent means of diffusing light, so arranged that these objects present vast surfaces emitting light in a nearly homogeneous and isotropic way, when low voltage is applied to the row of their photodiodes.

Oblects which include vast light-emitting surfaces have been already long ago produced and are widely used in advertising panels or decorative objects. The desired effect is achieved usually by means of one of the following mechanisms:

Glow discharge, chemiluminescence and diffusion of white light, which falls on a proper curtain from a powerful source positioned behind it.

alow discharge produces monochromatic light inside air-tight glass tubes, which are free from air and contain an inert gas under low pressure, while at their ends the electrodeβ are incorporated. Their emitting of light begins with a relatively high voltage. Usually they are supplied with mains voltage and there is also an additional component the "start" for rising the voltage even more during the starting of operation. The light produced by the glow discharge is impressive and intense, however the fragility of glass tubes, their difficult formation and their high operating voltage do not favour their use in constructing decorative objects of specific shapes.

Chemiluminescence is based on chemical reaction between two liquids and is of limited duration, about 12 hours, without capability of renewal.

The diffusion of white light by properly constructed curtains is widely used in illuminated panels with success because it offers easily forms, colours and letters visible from a long distance and extensible to a large space.

It is used also with success in constructing decorative objects for interior and exterior spaces, as well as in constructing illuminated toys, lanterns e.t.c.

A drawback of this method is the comparatively great demands in electric energy for the objects, since light is basically produced by white fluorescent or common incandescent lamps. On the other hand the heat quantity eritted by incandescent lamps of all types is such that a minimum distance beifcween the curtains and the light source is required, since the materials of the curtains are plastics sensitive to heat. The decorative objectsproduced in this way, therefore, are subject to limitations concerning their minimum volume, while their energy demands make their use, like portable decorative objects, prohibitive.

Lately from the domain of micro-electronics come more and more types of photodiodes known internationally as LSD's, the overwhelming majority of which emit light when are subject to forward voltage between 1,5 and 2,5V while they consume power between 20 and 130mW, in comparison with 750mW, consumed by tiny incandescent lamps having the same brightness and voltage supply. Their only drawback is that they emit light in a spotty way and in specific angles with reference to their main axis. So, if we try to cover a surface with photodiodes, firstly we shall not acquire a homogeneous photoemission from all its spots but many spotty emissions, secondly we shall not have an isotropic photoemission in space, since the lateral view of this surface diminishes its visibility to nullification and thirdly we must employ a great number of photodiodes per surface unit, meeting similar difficulties in connecting their leads. As a whole, in this way we shall receive a surface with poor results concerning photoemission as well as with high materials cost and constructing problems.

The present invention intends to realize solid objects which emit light in a homogeneous and isotropic way by means of their vast surfaces, creating desired three-di-mensional illuminated forms without the previously mentioned restrictions of methods applied so far or of possibly new but ineffectual ones. It has found,namely, a solution, which uses a relatively small number of photodiodes with very high brightness. The photodiodes are properly interconnected and bedded in a solid semitransparent material so that the intense beams of the photodiodes are reflected by a polished opaque surface, which encompasses like a concave mirror the system "photodiodes-semitransparent means". The result of this arrangement is that the rays of light falling from many directions on the concave mirror surface are reflected and diffused at random by the semi-transparent means, which fills it. Eventually light is emitted in a homogeneous way almost in all directions facing the concave mirror surface.

This specific arrangement, that is, the row of photodiodes-refleeting surface-semitransparent means of diffusion, is recommended by the invention as a structural unit for the construction of more bulky objects, which cay be extended in space without restrictions, if a proper design of the photoernissive structural units and a solution of the technical problems raising during assembly have preceded.

The objects, which will be nroduced with the aid of this method are expected to present the desired qualities of the "photoemission in a homogeneous and isotropic way witnout the risks existing in the conventional methods, that is, breaking or overheating deformation, while they operate supplied by very low voltages between 2 and 3V, by means of common portable batteries. So they are proper for applications in which the previous methods fail. A way of application of this method is described below with reference to the drawings, which illustrate only one specific embodiment, where:

Figure 1 is an enlargement of a top view according to the invention, where three photodiodes appear connected in parallel and forming a row.

Figure 2 is a cross section of a side view of a complete structural unit according to the invention, which unit let's name "photo-hive".

In order to have a row of photodiodes connected inparallel, we can so\der their leads with the aid of a conventional method of electrical engineering. The present invention proposes an alternative of making rows of photodiodes, whether, connected in parallel or in series, using like connectors fragments of cable rubber sheath with a cross-sectional area proportional to that of the leads, which we intend to connect. So, on the one hand we acquire in a short span of time a fixed cold joint,on the other hand we achieve automatically an insulation between the leads, without the presence of printed circuit boards or other means, which would obscure the object we construct by absorbing light.

As Figure 1 represents, the photodiodes (1), (2), (3) which are vertically arranged and have their top directed towards the back of the drawing paoer. They have also their leads bent horizontally at their bases so that the entry of leads, we want to joint in the common tiny tube in twos, is easy. So the nositive leads (characteri sed by the greater length compared with the negative ones) (4) and (6) of the photodiodes (1) and (2) respectively are jointed together since they are positioned in the gap of the tiny tube (10), which we acquired from the rubber sheath of a stripped cable. In a similar way the positive leaas (6) and (8) are connected by means of the tiny tube (1), and the negative ones (5) and (7) by means of (11) as well as (7) and (9) by means of (13).

On the basis of the previously mentioned way or of another conventional method, we think that we have acquired a row of photodiodes ALGaAs connected in parallel. A preferred type of photodiodes has been found by the invention, to be that characterised as HLMP- 100/4101 of the manufacturing company HEWLETT PACKARD, without excluding the use of other types with different advantages. Light produced by this specific type of photodiodes is dark red with a peak at 650nm, while the required power supply for each photodiode is 37mW and the forward voltage lies between 1.8 and 2.2V.

This row is represented as (16), in the Figure 2.

According to the present invention the construction of the basic structural unit, which we naujed "photo-hive", is achieved in the following stages:

Firstly, the concave mirror surface (14) is positioned horizontally on a fixed base, with the concavity directedupwards.

secondly this concavity is filled with the material intended for playing the role of the means causing the light diffusion. Luring this stage it is necessary for the means to be fluid at the prospect of being soon solidified. As such material, which is represented in Fig.2 with the number (15), is proposed semitransparent silicone glue, without excluding other materials such as thermoplastics or epoxy glues.

Thirdly, the row of photodiodes (16) is bedded and firmly retained in the, still, fluid means of diffusion (15), with the tops of photodiodes facing the reflecting surface.

Fourthly, after the solidification of the means of diffusion (15) and the cooling of the whole system, follows the addition of the final cover (17), which consists of an also semitransparent means of the same or different nature in comparison with that of the layer (15). This addition presupooses a moulding for giving the final desired form to the area (17), which will constitute the light emitting area of the "photo-hive", when the required voltage will be applied to the ends of the row of photodiodes.

It should be noted that during the addition of the cover (17) the leads (18), (19) (of the row of photodiodes) tnat seem to coincide in the side view of Figure (2), are kent out of that cover.

Claims

1. Method for creating objects, which emit light in a homogeneous and isotropic way by means of their vast surfaces with a low voltage supply, characterized in that the desired effect is achieved by bedding a row of powerful photodiodes (16) in a semitransparent means of light diffusion (15), which fills the concavity of a basic concave mirror surface (14) so that the emission cone of the photodiodes (16) is directed towards the concave surface (14), and then by laying on the means of diffusion (15) in full contact, a new layer (17) of a semitransparent means of diffusion, which is whether shaped in advance in a desired solid form or it takes this form during the laying on, after the means is cast in a matrix and shaded by pressing it on the already solid means of diffusion (15) of the concavity, until it is cool enough and hence solid itself, and we make sure that during the whole process the leads of the row of photodiodes (13), (19) are electrically insulated and conducted by means of cables to the exterior of the object we construct, so that it is possible to apply the proper voltage for the starting of photoemission. The different succession of laying the various means mentioned previously or their enrichment with more advantageous materials, provided that the arrangement remains the same and therefore so does the functional result, is however not escluded.

2. Method for creating objects which er.it light ac cording to Claim 1, characterised in that the row of photodiodes (16), which is bedded in the semitransparent means of diffusion (15), can be made without using the conventional ways of electrical engineering containing usually the soldering of the leads, but using a proposed alternative, according to which the desired connections are achieved inside the tiny tubes (10), (11), (12), (13) acquired by stripping the proper cable and specifically in the gap of these tiny tubes, which have a sufficient length, are guided, two at a time, the leads we want to joint and after these leads are pushed until they are in contact in a sufficient length, they are retained in a steady contact, if of course a proper tiny tube is chosen with a sufficient width (diameter) and elasticity, so that the tightening of the leads following one another becomes effective.

3. Objects which emit light in a homogeneous and isotropic way by means of their vast surfaces characterized in that they have a basic reflecting surface (14), while in front of it and in contact with this surface there are one, two or even more succesive layers of semitransparent means (15), (17) which diffuse light and in addition a row of powerful photodiodes (16) is bedded in the layers of the semitransparent means and is capable to cover the reflecting surface (14), as much as possible with their tops facing the surface, while the leads of tne row (18), (19) end up out of the object, ready to be connected with the proper d.c. voltage source required by the row ( 16) .

4. Objects which emit light according to Claim 3 characterized in that the light-emitting area (17) in combination with the basic reflecting surface (14), have been formed so that they can compose a three-dimensional mock-up of whatever form, whether they come from the domain of imagination creating new designs or from the domain of established forms and shapes, where a faithful copy on a scale proper for the available reflecting surface is sufficient, if of course it is not proh ibited by patents or registered trademarks.

5. Objects which emit light according to Claims 3 and 4 characterized in that the reflecting surface (14) is small enough, so that for its cover 1 to 20 powerful photodiodes (16) are sufficient and therefore the supply source can have a small size raising, in this way, no problems, when somebody wants to bear the whole "source-light emitting object" system, so positioned that it doesn't trouble his movements.

6. Objects which emit light according to Claims 3,4 ana 5 characterised in that very few photodiodes (16) are required for covering the basic surface (14) and therefore the supply source can have a small size, so that it can be easily positioned in a battery case having the size of a coin, and therefore the formation of light emitting jewels and rosettes is easy, since the supply source in carried with them or is positioned in a very short distance.

7. Objects which emit light according to Claims 3, 4,5 and 6 characterized in that the light emitting object is formed in a desired shape, and the two leads (18), (19) of the row of photodiodes (16) are in steady contact and 2 fragments of flexible single conductor cable having a length at the most about 40cm each and while each first end of the two fragments is connected with its respective lead, the other end of each of them reaches to the proper point of a small battery case, so that the source inside the case has its positive pole connected with the positive lead, via the respective cable and its negative pole with the negative lead via the other cable. The use of whatever microswitch is possible but the invention proposes a switch which is more economical and elegant, consisted of the male and female part of a metallic "snap" and connected properly to the point where we want to open and close the circuit of the system "object-cable a' -battery case-cable b'- object", so that we can permit or not the flow of current by"buttoning" or "unbuttoning" the "snap".

3. Objects which emit light according to Claim 3 characterized in that in order to increase the light emittins surface and perhaps the solid angle of emission, the basic reflecting surface is not uniform but it consists of many others planned in advance so that they fit one another like the pieces of a puzzle creating therefore, whether a surface emitting like a mosaic, if gaps are left in between and photodiodes of different, colors are used, or a surface emitting in a uniform way, if on these "photo-hives" is layed a new semitransparent material and its external surface is so formed that it produces the impression of a bas-relief or of a painting.

9. Uses of the objects which emit light in a homogeneous and isotropic way by means of their, vast surfaces and which are supplied by low voltages, characterized in that these objects, being completely safe, can solve many problems that require light emitting surfaces with low voltage supoly and distinct shapes.

10. Uses of the objects which emit light according to Claim 9, characterized in that the light-emitting objects with a small number of photodiodes can be used as jewels or rosettes with various signs.

11. Uses of the objects which emit light, according to Claim 9 characterized in that the light-emitting objects can be parts of toys or breloques, components of interior decoration objects, of cars, shop-windows, shops, music halls or can be used as self-same in the previously mentioned applications.

12. Uses of the objects which emit light according to Claim 9, characterized in that with structural units which we can work out concerning their shape and colour it is possible to create illuminated panels with various gra hies, especially when with the aid of the progress of technology the construction of photodiodes of the whole spectrum of colours will be possible, besides these units in their simpler form, circular, rectangular or rhomboil, even with the 3 colours we employ today, can be positioned in digital advertising panels similar to those already in use, offering perhaps better results for the advertisements showed.

AMENDED CLAIMS

[received by the International Bureau on 12 November 1993 (12.11.93);

original claims 1,3 and 9 amended; remaining claims unchanged

(6 pages)]

1. Method for creating objects which emit light in a homogeneous and isotropic way by means of their vast surfaces with a low voltage supply, characterised in that the desired effect is achieved as follows: we form a row of high intensity photodiodes (16), which are standardized, put on the market and known as "high intensity LED-lamps", making sure that the distances between the photodiodes are sufficient, so that their light covers a maximum area with a. minimum number of them and their emission cones are directed towards the same direction, a basic concave reflecting surface (14), the area of which is proportional to the area covered by the light of the photodiodes

belonging to the row (16), is arranged opposite to this row so that the high intensity light beams of the diodes are falling on this surface there is also a semitransparent means of diffusing light (15), which is either properly formed in advance in a solid state and is pocketed in the surface (14) pocketing at the same time the row (16), or is cast in a fluid state filling the cavity offered by the reflecting surface (14) and enclosing the above arranged row (16) at the prospect of being aolidified in a short time^* after that we lay on 2-new layer (17) of a semitransparent means of diffusing light, in full contact with the diffusing means (15) of the cavity, which layer is of the same or of different composition compared with the previous one^* the new layer (17) also is either formed in advance in a desired solid state joined properly with the layer (15), or it takes this form during the laying on, after it has been cast as a fluid in a proper mould and is fitted by pressing on the already solid layer (15) until it is solidified itself, while during the whole process we make sure that the leads (18), (19) of the row of photodiodes (16) are electrically insulated and conducted by means of cables to the exterior of the object we construct, so that it is possible to apply the proper voltage for the starting of photoemission* the different succession of laying the various means mentioned previously or their enrichment with more advantageous materials, provided that the arrangement remains the same and therefore so does the functional result, is however not excluded.

2. Method for creating objects which emit light according to Claim 1, characterised in that the row of photodiodes (16), which is bedded in the semitransparent means of diffusion (15), can be made without using the conventional ways of electrical engineering containing usually the soldering of the leads, but using a proposed alternative, according to which the desired connections are achieved inside the tiny tubes (10), (11), (12), (13) acquired by stripping the proper cable and specifically in the gap of these tiny tubes, which have a sufficient length, are guided, two at a time, the leads we want to joint and after these leads are pushed until they are in contact in a sufficient length, they are retained in a steady contact, if of course a proper tiny tube is chosen with a sufficient width (diameter) and elasticity, so that the tightening of the leads following one another becomes effective.

3. Objects which emit light in a homogeneous and isotropic way by means of their vast surfaces characterised in that they have a basic reflecting surface (14), while in front of it and in contact with this surface there are one, two or even more successive layers of semitransparent means (15), (17) which diffuse light and have also a row of standardized high intensity photodiodes (16) implanted in the layers of the semitransparent means, sufficiently spaced out so that they can cover the reflecting surface (14) with a minimum number of diodes and with their emission cones directed towards the reflecting surface (14) while the leads of the row (18), (19) end up out of the object, ready to be connected with the proper voltage source required by the row (16).

4. Objects which emit light according to Claim 3 characterized in that the light-emitting area (17) in combination with the basic reflecting surface (14), have been formed so that they can compose a three-dimensional mock-up of whatever form, whether they come from the domain of imagination creating new designs or from the domain of established forms and shapes, where a faithful copy on a scale proper for the available reflecting surface is sufficient, if of course it is not prohibited by patents or registered trademarks.

5. Objects which emit light according to Claim 3 and 4 characterized in that the reflecting surface (14) is small enough, so that for its cover 1 to 20 powerful photodiodes (16) are sufficient and therefore the supply source can have a small size raising, in this way, no problems, when somebody wants to bear the whole "source-light emitting object" system, so positioned that it doesn't trouble his movements.

6. Objects which emit light according to Claims 3, 4 and 5 characterized in that very few photodiodes (16) are required for covering the basic surface (14) and therefore the supply source can have a small size, so that it can be easily positioned in a battery case having the size of a coin, and therefore the formation of light emitting jewels and rosettes is easy, since the supply source is carried with them or is positioned in a very short distance.

7. Objects which emit light according to Claims 3, 4,5 and 6 characterized in that the light emitting object is formed in a desired shape, and the two leads (18), (19) of the row of photodiodes (16) are in steady contact and 2 fragments of flexible single conductor cable having a length at the most about 40cm each and while each first end of the two fragments is connected with its respective lead, the other end of each of them reaches to the proper point of a small battery case, so that the source inside the case has its positive pole connected with the positive lead, via the respective cable and its negative pole with the negative lead via the other cable. The use of whatever microswitch is possible but the invention proposes a switch which is more economical and elegant, consisted of the male and female part of a metallic "snap" and connected properly to the point where we want to

open and close the circuit of the system "object-cable a'-battery case- cable b'- object", so that we can permit or not the flow of current by "buttoning" or "unbuttoning" the "snap".

8. Objects which emit light according to Claim 3 characterized in that in order to increase the light

emiting surface and perhaps the solid angle of emission, the basic reflecting surface is not uniform but it consists of many others planned in advance so that they fit one another like the pieces of a puzzle creating therefore, whether a surface emitting like a mosaic, if gaps are left in between and photodiodes of different, colors are used, or a surface emitting in a uniform way, of on these "photo-hives" is layed a new semitransparent material and its external surface is so formed that it produces the impression of a bas-relief or of a painting.

9. Uses of the objects which emit light in a homogeneou and isotropic way by means of their vast surfaces, when supplied by low voltages, which objects consist of a combination of a concave reflecting surface (14), a row of standardized high intensity photodiodes (16) covering opposite this surface using a minimum number of photodiodes and of successive layers of semitransparent means diffusing light (15), (17) which fill the cavity formed by the surface (14) and also enclose the photodiodes of the row (16) characterized in that these objects, being completely safe, can give solutions to many problems, which require light-emitting surfaces supplied by low voltages and with a sufficiently distinct shape.

12. Uses of the objects which emit light according to Claims 9, characterized in that with structural units which we can work out concerning their shape and colour it is possible to create illuminated panels with various graphics, especially when with the aid of the progress of technology the construction of photodiodes of the whole spectrum of colours will be possible, besides these units in their simpler form, circular, rectangular or rhomboid, even with the 3 colours we employ today, can be positioned in digital advertising panels similar to those already in use, offering perhaps- better results for thee advertisements showed. STATEMENT UNDER ARTICLE 19

In relation to the amended Claims which are sent enclosed with the present, we should clarify the following:

Changes are made in the contents of the main claims 1, 3 and 9. An amendment common to the mentioned Claims, is the replacement of the expression "row of powerful photodiodes (16)" written in the initial registration, with the expression

"row of standardized high intensity photodiodes (16)" written in the amended Claims. So it is made clear that common

diodes are used which are put on the market with a special characteristic (the high intensity of light emission) and no high technology is required for incorporating them in the objects constructed on the basis of the present invention.

Therefore it is obvious that there is a difference between the Document mentioned in the International Search Report as "US, A, 3 875 456 (HITACHI) (01-04-75), and the present invention. This is concluded from the drawings, the description and the Claims where it is evident, that common p-n

junctions are used and not standardised onejr like whole LED-lamps. That is, only their "nuclei" are used so that the volume occupied by them can be reduced.

Another change in the content of the three amended Claims is the clarification that the photodiodes of the row (16) have sufficient distances between them, so that a maximum surface can be covered by a minimum number of photodiodes making apparent in this way, the basic difference between the present invention and the above Document "US, A, 3 875 456 (HITACHI) (01-04-75)". The latter intends to "squeeze" the light sources as much as possible, in a minimum amount of space, without taking an interest in arranging the beams of the reflected rays so that they are reflected without fail by the basic reflecting surface, while the present invention intends to space out a minimum number of light sources in a maximum surface, providing for the direction of the existing emission cones of standardized photodiodes, which direction of the cones must be towards the reflecting surface and the cones must diffuse light rays in the most efficient way in the whole space (volume) of the layers of semitransparent means of diffusion, which enclose the photodiodes and form the vast light-emitting surface of the object constructed on the basis of the present invention.