KR100756255B1 - Light extractor for a light guide lamp - Google Patents

Abstract

The invention relates to a light guide lamp 1 in which a useful surface, ie a surface facing the light emitting surface 5 of the light guide lamp 1 in use, comprises a predetermined distribution of the diffusion points 10 and a compensation distribution of the reflection points 9. A light extractor 8 for) is provided. The light extractor 8 makes it possible to obtain illumination with preselected properties. The present invention also provides a method of determining the distribution of points to obtain a highly uniform illumination.

Description

Light extractor for light guide lamps {LIGHT EXTRACTOR FOR A LIGHT GUIDE LAMP}

The present invention relates to a light extractor for a light guide lamp. More specifically, the present invention relates to a diffuser and a light guide lamp including the diffuser, a method for determining a distribution along the main direction of propagation of a diffusion point on a light extractor, and a computer program suitable for performing the steps of the method. It is about. The invention also relates to a light extractor and a method for producing silk screens.

Definitions of terms used in the present specification and claims are as follows.

"Diffuser" means a light guide structure in which a light extractor is installed in order to partially guide and partially emit light.

"Diffusion point" means a point on the surface with optical properties that results in a group of rays in which incident light is reflected within the local bending angle of the surface, thus comparable to a point light source, in principle a hole; This can also be used.

-The term "direction" is used in the sense including the curve direction.

Known light guiding lamps are generated by one or more light sources to provide light paths, ie light that is irradiated to a closed structure having a surface at least partially transparent and at least partially reflecting inward. Light rays propagate through a series of continuous reflections within the structure and are emitted from it in a somewhat gradual manner. Light guides obtained using an internal total reflection film (or TIR film) are particularly effective.

The TIR film is known from, for example, European patent EP 0 225 123, the details of which are referred to the European patent. An example of the TIR film is a brand name OLF (Optical Lighting Film) produced and sold by the Minnesota Mining and Manufacturing Company. They have the shape of a soluble sheet or tape in which a series of parallel micro reliefs having approximately triangular cross sections are formed on the surface. The TIR film can be applied to the surface of a transparent carrier material, and the micro relief is directed outwards simultaneously with the propagation direction, thus forming an effective light guide. Indeed, due to the optical properties of the film, and as disclosed, for example, in U.S. Patent No. 4,805,984 (for more details see this document), an angle smaller than the predetermined critical angle (θ _max ) with respect to the direction of propagation of the main is given. The forming light is always internally reflected and the light forming an angle larger than the critical angle θ _max with respect to the main propagation direction is applied to the TIR film at an angle smaller than a certain angle depending on the angle θ with respect to the vertical line. When incident, it is internally reflected. Thus, contrary to the present definition, in the following description and claims, the angle of incidence of the light ray to the surface is assumed to be formed by the light ray with respect to the plane in contact with the surface.

The angle θ _max depends on the properties of the TIR film and is 27.6 ° for the OLF film described above.

Another material used in light guide lamps is the so-called multilayer optical film disclosed, for example, in US Pat. No. 5,882,774.

A special device, called a light extractor, is inserted into the light guide to control the diffusion of a portion of the light traveling in the light guide, thereby causing a portion of the light beam to enter the TIR film at an angle exiting the light guide.

To this end, known light extractors typically comprise a white diffused surface and are applied to a three-dimensional body (see eg Italian Patent Application No. TO98A000513) or an inner surface of the light guide arranged in the axial direction of the light guide. Body (see eg European Patent Application EP-A-1006312).

The technical problem in this invention is providing the light extractor for light guide lamps which can obtain the illumination which has a preselected characteristic, for example, a highly uniform illumination.

A first aspect of the invention relates to a light extractor for a light guide lamp, the feature of which is that the useful surface comprises a predetermined distribution of diffusion points and a complementary distribution of reflection points.

In the present specification and claims, the term "useful surface" means a surface that faces the light emitting surface of the light guide lamp when the light extractor is used.

By controlling the distribution of the diffusion points—and thus the compensation distribution of the reflection points—the incident light to the reflection point propagates through the reflection and the incident light to the diffusion point deviates at such an angle that is partially emitted from the lamp. When using the light extractor, it is possible to control the light diffusing characteristic point by point based on the desired result.

Advantageously, the useful surface comprises a reflective base layer and a predetermined distribution of diffusion points on the reflective base layer.

By doing so, the manufacture of the light extractor is simplified.

More preferably, the reflective base layer comprises a microprism-free side of the TIR film. In particular, the reflective base layer can be composed of the above-described OLF film or optical multilayer film.

In one embodiment, adjacent diffusion points of a predetermined distribution are at a reduced distance along the main propagation direction from the light entry end to the opposite end.

Such extractors used in light guide lamps with a single illumination system provide uniform illumination along the main propagation direction.

In another embodiment, the distribution of diffusion points is symmetric about an intermediate axis perpendicular to the main propagation direction.

Such extractors are particularly useful for light guide lamps with two symmetrical illumination systems at two ends.                 

In this case, in a particularly preferred manner, the adjacent diffusion points of the point distribution are at a reduced distance from each end of the extractor to the intermediate axis perpendicular to the main propagation direction.

Such extractors provide uniform illumination along the direction of main propagation.

Advantageously, the predetermined distribution of diffusion points is imprinted on the reflective base layer through silk screen printing.

Silk screen printing makes it possible to easily achieve any point distribution even on non-absorbent surfaces at acceptable small distances between diffusion points.

A second aspect of the invention relates to a diffuser for a light guiding lamp, the diffuser comprising a light extractor as described above, which also transmits light beams forming an angle greater than a predetermined critical angle along the main propagation direction and And a light emitting surface that internally reflects an incident light beam at an angle smaller than a predetermined critical angle.

Typically, the light emitting surface comprises a transparent support layer and an internal total reflection film applied to the transparent support layer.

Preferably, the total internal reflection film has a micro relief directed outward and oriented parallel to the main propagation direction.

In particular, the light emitted from the TIR film by the aforementioned OLF has a fixed output angle with respect to the longitudinal direction of the micro relief, and this configuration can minimize the visual perception of the shadow caused by the angle.

Preferably, the light extractor has a cross section selected from the group consisting of a straight line, a semicircle, a semi-ellipse, a parabola, a semi-parabola, or a cross section according to a higher-order curve, and the light emitting surface has a straight line, semi-circle, semi-ellipse, parabola. , A cross section selected from the group consisting of semiparabolas, or a cross section according to a higher order curve.

Further, preferably, the maximum distance between the light extractor and the light emitting surface in the plane perpendicular to the main propagation direction is 1 of the moisture of the length of the light extractor in the main propagation direction, more preferably about 1/20.

In this way, light propagates with a sufficiently small number of incidences and low losses.

Another aspect of the invention relates to a light guide lamp comprising a diffuser as described above and an illumination system adapted to project light to the diffuser at an angle smaller than the critical angle of the light emitting surface.

Light rays incident on the light emitting surface first and projected to the diffuser are totally internally reflected, and light rays incident on the light extractor first are reflected or diffused depending on whether they enter the diffuse point or the reflective point.

Another aspect of the invention relates to a diffuser for a light guide lamp having an illumination system suitable for projecting light from a light source to a diffuser at an angle smaller than a predetermined critical angle, wherein the light propagates at an angle smaller than the critical angle. On a useful surface of a light extractor coupled to a luminescent surface that transmits and internally reflects a light beam propagating at an angle greater than the critical angle, the invention relates to a method for determining the distribution along the main propagation direction of a diffusion point and reflecting the rest , This way,

(a) setting the first point of the distribution as the last point of incidence on the light extractor closest to the illumination system of light rays propagating along a trajectory of a preselected type,

(b) setting a second point of distribution as the last point of incidence on the light extractor furthest from the illumination system of light rays propagating along a trajectory of a preselected type,

(c) For each point in the point distribution, the new point in the distribution is equally illuminated by a first point light source arranged at a preselected point of the distribution and a second point light source arranged at the next adjacent point of the distribution. Iteratively determining as a point of the extractor, wherein the intensity of the point light source is determined as a function of the intensity of the light source and the characteristic distance of the trajectory of the preselected type.

In this way, the light extractor having a predetermined light distribution makes it possible to obtain sufficiently uniform illumination along the main propagation direction during its use.

Preferably, in steps (a), (b) and (c), the trajectory types are classified based on the number of reflections in the diffuser.

In particular, in step (c), when the preselected type of trajectory consists of light rays from a light source of a light guiding lamp that directly reaches the light extractor, the luminous intensity of each point light source is the absorption diffusion coefficient of the light extractor to the luminous intensity of the light source. Is determined by multiplying and dividing the distance from the light source to the point of the source point by the squared value.

Thus, the induced tissue configuration is such that each diffusion point produces a constant emission at each angle and is considered to be independent of the angle of incidence of the light beam.

Conversely, in step (c), when the preselected type of trajectory consists of light rays reaching the light extractor after the light rays from the light source are reflected once by the light emitting surface and optionally by the light extractor, The luminous intensity of the point light source is multiplied by the luminous intensity of the light source by the absorption diffusion coefficient of the light extractor, multiplying each reflection on the light emitting surface by the absorption reflection coefficient of the light emitting surface, and for each reflection on the light extractor It is determined by multiplying the absorption reflection coefficient of the extractor and dividing by the square value of the projection distance along the main propagation direction of the light beam portion taking into account the point from the light source to the first reflection point.

Thus, to simplify the calculation, the light emitting surface is considered to be arranged in the extractor.

Preferably, the method is

(d) determining a second distribution of at least points through steps (a), (b), and (c) for different types of trajectories,

(e) adding each second distribution of points to the distribution of points.

By doing so, the accuracy increases as the type of trajectory increases, and the uniformity of illumination obtainable further increases.

In addition, if the extractor is inserted in a light guide lamp with a second illumination system that reflects the first illumination system and is arranged at the opposite end thereof,

(f) adding the reflection points of each point in the point distribution to the point distribution.

Also, preferably, the method                 

(g) repeating the distribution of points at regular intervals along a direction perpendicular to the main propagation direction of the extractor.

By doing so, the extractor exhibits a distribution of the stripe of diffusion points, and the illumination is also sufficiently uniform in the plane perpendicular to the main propagation direction.

More preferably, during the reproducing of step (g),

(g1) further comprising alternately executing the distribution of points at a predetermined interval forward and backward in the main propagation direction.

By doing so, it is possible to reduce the distance between points within the minimum distance imposed by the physical implementation of the extractor.

Preferably, the method is

(h) rejecting from the distribution of points points representing a distance greater than a preset minimum distance from immediately adjacent points.

By doing so, it is possible to prevent obtaining a distribution with higher accuracy than in the case of physical implementation of the extractor.

Another aspect of the invention relates to a computer program comprising program code means suitable for performing the steps of the method when the program is run on a computer.

In an advantageous parametric implementation, the computer program comprises means for receiving as input one or more of the following parameters.

The critical angle of the luminescent surface to which the extractor is coupled,                 

The shape and / or size of the extractor,

The shape and / or size of the luminescent surface to which the extractor is coupled,

The maximum distance of the extractor from the emitting surface to which the extractor is coupled,

-The number, type, luminosity and characteristics of the light source of the lighting system to which the extractor is coupled,

The minimum distance between the points in the point distribution,

The absorption reflection coefficient of the extractor,

The absorption diffusion coefficient of the extractor,

An absorption reflection coefficient of the luminescent surface to which the extractor is coupled,

The type (s) of the trajectory under consideration or the maximum number of reflections under consideration.

In order to facilitate the management of multiple simulations, the computer program may include means for saving the parameters contained in the file and means for loading the parameters from the file.

Preferably, the computer program generates one or more of the following.

The coordinates of the points in the distribution,

The percentage density of the points in the distribution at the elementary interval,

-Reports of preset parameters,

-Graphical representation of the point distribution,

A file of points of distribution in a format readable by a printing press, in particular a silk screen printing press,                 

The geometric arrangement of each illumination system of the light guide lamp to which the extractor is applied, as a function of a predetermined maximum distance between the extractor and the emitting surface and a predetermined critical angle of the emitting surface.

Table format, graphical display and report of set parameters are useful in multiple simulations; Files in a printer-readable format, such as Autocad ^™ and MacIntosh ^™ , can be integrated into the extractor manufacturing stage, and the geometrical arrangement is typically consistent with determining the focus of the reflective parabolic surface of the lighting system, and thus more than the critical angle of the emitting surface. It satisfies the requirement of projecting light into the diffuser small.

Typically, a computer program may be implemented by computer readable means.

Another aspect of the invention relates to a diffuser for a light guide lamp having at least one illumination system suitable for projecting light from a light source to the diffuser at an angle smaller than a predetermined threshold angle θ _max , wherein the critical angle θ _max . On the useful surface of the light extractor coupled to the light emitting surface which transmits the light propagating at a smaller angle and internally reflects the light propagating at an angle greater than the critical angle θ _max , according to the main propagation direction of the diffusion point. To determine the distribution and to reflect in the rest,

(a) defining a diffusing-points-density variable for each interval of preselected length along the main direction of propagation of the useful surface of the extractor;

(b) defining a luminosity variable for each interval of preselected lengths along the main direction of propagation of the luminescent surface;

(c) expressing the value of the luminosity parameter of each interval of the emitting surface as a function of the diffuser point density variable of the extractor,

(d) calculating the values of the diffusion point density parameters of the extractor to be equal to the values of the luminosity parameters of all intervals of the light emitting surface.

In the first method described above, the light extractor having the distribution of light determined as described above can obtain sufficiently uniform illumination along the main propagation direction in use.

In a preferred embodiment of the method described above,

Step (a) comprises an auxiliary step (a1) of presetting the value of the diffusion point density parameter to zero,

Said step (b) comprises an auxiliary step (b1) for presetting the value of the luminosity variable to zero;

The calculating step (d) is carried out in the following steps, namely

(d1) evaluating the value of the luminosity parameter of each interval of the light emitting surface represented in step (c) according to the current value of the diffusion point density parameter of the extractor,

(d2) individually increasing the value of the diffusion point density parameter of the extractor,

(d3) iteratively repeating steps (d1) and (d2) until the values of the luminous intensity parameters of all intervals of the light emitting surface evaluated in step (d1) become equal to each other.

Preferably, the step (c) of expressing the brightness parameter,

(c1) dividing the light projected by the at least one illumination system into a finite number of rays each having an initial luminance value,

(c2) increasing the luminosity parameter of each interval of the luminescent surface by the value of the final luminosity of each ray incident on the luminescent surface at an angle greater than its critical angle θ _max with respect to the main propagation direction, From here,

* Upon incidence of each ray at the interval of the extractor, an assessment of whether the ray is reflected or diffused is made based on the value of each diffusion point density parameter,

** In the case where a light beam is reflected, the light intensity value of the reflected light beam is obtained by multiplying the light intensity value of the incident light beam by the absorbing reflection coefficient of the extractor,

** In the case where light rays are diffused, the light intensity value of each diffuse light ray is obtained by multiplying the light intensity value of the incident light ray by the absorption diffusion coefficient of the extractor,

* With respect to the main propagation direction, at each incidence incident on the light emitting surface at an angle smaller than its critical angle θ _max , the luminous intensity value of the reflected ray is obtained by multiplying the luminous intensity value of the incident ray by the absorbed reflection coefficient of the emitting surface. Lose.

Preferably, the method is

(e) repeating the distribution of points at regular intervals along a direction perpendicular to the main propagation direction of the extractor.

By doing so, the extractor exhibits a distribution of the bands of the diffusion points, and the illumination is also sufficiently uniform in the plane perpendicular to the main propagation direction.

More preferably, the method, during the reproduction of step (e),

(e1) further comprising alternating the distribution of points forward and backward in the main propagation direction at regular intervals.

By doing so, it is possible to reduce the distance between points within the minimum distance imposed by the physical implementation of the extractor.

Preferably, the method is

(f) rejecting from the distribution of points points representing a distance greater than a preset minimum distance from immediately adjacent points.

By doing so, it is possible to avoid obtaining a distribution with higher accuracy than the physical implementation of the extractor.

Another aspect of the invention relates to a method for manufacturing the above-described light extractor, which method,

(a) providing a reflective base layer;

(b) silk screen printing diffusion points on the reflective base layer according to a predetermined distribution of points.

Although the aforementioned light extractors can be manufactured in other ways, such as by printing or otherwise applying a distribution of diffusion points and a compensation distribution of reflection points on an intermediate substrate, for example, silk screen printing on a reflective base layer is a non-absorbing surface. Any desired point distribution on the image can be easily obtained with an acceptable distance between the smallest spread points.

Preferably, printing step (b) is performed by printing the distribution of points obtained by one or the other of the above methods.

Another aspect of the invention relates to a silk screen embodying the distribution of points obtained by one or the other of the above methods.

The features and advantages of the invention are described below with reference to the embodiments shown by way of non-limiting example in the accompanying drawings.

1 is a schematic diagram showing, without scale, a light guide lamp according to a first embodiment of the present invention;

2 is a plan view of the light guide lamp of FIG. 1 for explaining a first method of determining the distribution of diffusion points in accordance with the present invention.

3 is a block diagram of the method shown in FIG.

4 to 6 are similar to FIG. 2, a plan view of the light guide lamp for explaining the method in detail.

7-9 are further block diagrams of the method.

10 and 11 are schematic views showing a preferred embodiment of the extractor according to the invention.                 

12-14 are schematic diagrams showing another embodiment of a light guide lamp embodying the present invention.

15 is a block diagram of a computer program suitable for performing the first method of the present invention for determining the distribution of spread points.

FIG. 1 shows a light guiding lamp 1 having two lighting systems 2, 2a and a parallelepiped box diffuser 3 which is coupled to the lighting system via respective glass 4, 4a. . Alternatively, the light guide lamp 1 may comprise only a single illumination system, for example an illumination system 2.

The diffuser 3 comprises a light emitting surface 5 and a light extractor 8, which will be described in detail later. The light emitting surface 5 is made of a rigid material, such as polycarbonate, for example, so that the inner (shown in FIG. 1) or the outer transparent support layer 6 coated with a TIR film, such as an OLF film from the Minnesota Mining and Manufacturing Company. ).

The thickness of the diffuser 3, i.e. the distance h between the extractor 8 and the light emitting surface 5, is preferably one, for example 1/20, of the water of the length of the extractor in the direction of the main propagation. By having this ratio, light propagates with a sufficiently small number of incidences and a small loss.

The TIR film 7 is preferably arranged such that the micro relief indicated by several lines in FIG. 1 is oriented horizontally. In fact, the optical properties of the OLF film are such that the light rays emitted therefrom are emitted at a predetermined angle α, which is about 15 ° with respect to the direction of the micro relief, and its horizontal arrangement minimizes the visual perception of the shadow formed by the output angle. It is decided.

As in the conventional application of the OLF membrane, the micro relief is preferably faced out of the diffuser 3.

The lighting system 2, 2a comprises light sources 21, 21a, respectively. The light source is, for example, a fluorescent lamp of 36 W output, placed at the focal point of the parabolic reflectors 22, 22a. The power and control components of the lighting system 2, 2a are not shown in detail because they are conventional.

Each illumination system 2, 2a is designed to project light onto the diffuser 3 at an angle less than the critical angle θ _max of the light emitting surface 5 or its TIR film 7 (θ in the case of the OLF film described above). _max = 27.6 °).

In terms of the parabolic geometric characteristics, when the light source 21 is placed at the focal point, all the light rays emitted from the focal point are reflected parallel to the axis, and the condition is that the distance δ between the focal point and the glass 4 is Obtained when equal to one.

The light extractor 8 consists of a substantially two-dimensional body having a reflective base layer 9 and a plurality of diffusion points 10 arranged in the reflective base layer 9 according to a predetermined distribution.

The reflective base layer 9 itself may be the body of the extractor 8 or may be provided as a reflective coating on a substrate (not shown) which is for example polycarbonate or glass. Preferably, the reflective base layer 9 consists of the microprism-free side of the OLF film described above. The diffusion point 10 is preferably a white point, but may be a point of a different color or silk screen printed on the reflective base layer 9.

Thus, the light extractor 8 performs with a plurality of basic extractors arranged on the reflective surface. In fact, the light incident on the reflective base layer 9 is reflected at the same angle as the angle of incidence and the light incident on the diffusion point 10 is under consideration, i.e. above the plane angle in particular in the case of the plane extractor 8 being considered. At the diffusion point 10 it is reflected as a group of rays distributed over the internal solid angle of the extractor.

Therefore, referring to FIG. 1, three situations occur as follows.

If a light beam is incident on the reflecting base layer 9 of the extractor 8 at an angle β ₁ with respect to the main propagation direction indicated by the axis x, as in the light beam R ₁ , the light beam is in the diffuser 3 at the same angle as the angle of incidence. Internally reflected from. That is, it further propagates in the diffuser 3 at the same angle β ₁ with respect to the propagation direction x directed towards the light emitting surface 5.

Similarly, if a ray enters the light emitting surface 5 at an angle β ₂ with respect to the main propagation direction x, like ray R ₂ , the ray is internally reflected in diffuser 3 at an angle equal to the angle of incidence. do. That is, it further propagates in the diffuser 3 at the same angle β ₂ with respect to the propagation direction x directed towards the light extractor 8.

When the light beam is incident on the diffusion point 10 of the extractor 8 at an angle β ₃ with respect to the main propagation direction x, like the light beam R ₃ , the light beam is diffused internally in the diffuser 3.

In the last case, the incident light beam R ₃ generates two groups of secondary light beams.

Light rays such as light rays R ₃₁ , R ₃₂ which form an angle smaller than the critical angle θ _max with respect to the main propagation direction x; These rays are directed entirely in the direction of propagation, or individually in the direction opposite to the direction of propagation, and further propagate in the diffuser 3.

A light beam, for example a light beam R ₃₃ , that forms an angle greater than the critical angle θ _max with respect to the main propagation direction x.

The last considered type of light, such as light beam R ₃₃ , is not internally reflected when it reaches the light emitting surface 5 but exits from it and contributes to the illumination of the light guiding lamp 1.

The light rays are always projected by the illumination system 2, 2a to the diffuser 3 at an angle smaller than the critical angle θ _max , and because of the transmission and reflection characteristics, the light rays are at the critical angle θ _max in the main propagation direction x. To form a smaller angle. For this reason, the reflective base layer 9 can be made from the side without the microprism of the same OLF film mentioned above.

From the above description, the special light extractor 8 of the present invention ideally provides non-limiting flexibility in the control of light rays exiting the light guide lamp 1, ie its illumination. In practice, this flexibility is limited only by the resolution of the diffusion point, and the method used to physically implement the light extractor 8 and the difficulty of the calculations necessary to determine the proper distribution of the diffusion point to provide the desired illumination. Is represented by                 

To this end, a first method of determining the distribution of the diffusion point of the light extractor 8 will now be described so that the light emitted by the light guide lamp 1 is as uniform as possible.

This method is described with reference to FIG. 2, which shows the light guide lamp 1 in plan view without scaling. In fact, considering the geometry of the light guiding lamp, since the fluorescent light sources 21, 21a are emitted with substantially equal light rays along their length, the optical system can be considered a two-dimensional system, ignoring the first approximation, Light rays from the light sources 21, 21a of the illumination system 2, 2a propagate in a direction with the component along the axis y perpendicular to the main propagation direction x.

First of all, assume that the light guiding lamp 1 comprises only an illumination system 2 whose light source 21 can be regarded as a point light source, as indicated by S in FIG. 2.

Light intensity at the light emitting surface 5 is generated only by light rays such as light ray R ₃₃ in FIG. 1. This is due to the plurality of point light sources formed at the diffusion point 10 on the extractor 8.

Fixing the viewpoint of the axis x to the end of the extractor 8 proximate the illumination system 2, the distribution of the diffusion point 10 on the extractor 8 along the main propagation direction x is W (x) = x1, x2, ..., xn, where x1, x2, ..., xn are the coordinates of each diffusion point 10 of the extractor.

In the method of the present invention, the following iterative method is used to obtain the desired distribution of diffusion points. Firstly, two diffused points on the extractor 8, optionally selected or preferably in the manner described later, with coordinates x ₁ and x ₂ , that is, W (x) = x ₁ , x ₂ is set. Assume that we only have (10). This is indicated by blocks 32 and 34 in FIG. Then, as indicated by block 35 of FIG. 3, the illumination is equally illuminated by a point light source disposed at a diffusion point with coordinates x ₁ and x ₂ , each luminous intensity being I (x ₁ ), I (x ₂ ). It is determined whether there is a point x ₃ on the extracted extractor 8. If present, point x ₃ is added to the distribution W (x) of the spread point as shown in block 36 of FIG. In this regard, since luminous intensity is the inverse of the square of the distance from the light source, if x ₁ <x ₂ then I (x ₁ )> I (x ₂ ), so point x ₃ is between points x ₁ and x ₂ . Is placed closer to x ₂ . That is, assuming that the distribution W (x) maintains order, then W (x) = x ₁ , x ₃ , x ₂ . Subsequently, the coordinates x _1, x ₃ is disposed on the diffusion point, and the same illuminated point x _4, and the coordinates by a point light source, each of the light intensity _{I (x 1), I (} x 3) x 3, A point x ₅ equally illuminated by a point light source disposed at a diffusion point of x ₂ and each of luminous intensities I (x ₃ ), I (x ₂ ) is calculated, and thus the distribution W (x) = x ₁ , x ₄ , x ₃ , x ₅ , x ₂ , are obtained, then W (x) = x ₁ , x ₆ , x ₄ , x ₇ , x ₃ , x ₈ , x ₅ , x ₉ , x ₂ Etc. are obtained.

Thus, blocks 35 and 36 in the block diagram of FIG. 3 are points of an extractor which are equally illuminated by a first point light source arranged at a preselected point of the distribution and a second point light source arranged at adjacent points of the distribution, the point distribution being Represents an iterative calculation of new points in the distribution for each preselected point of. The iterative calculation ends when no new point can be determined, and therefore it is to be understood that the cycle is repeated for each index i of the distribution W of the spread point.

Nevertheless, exponential increments are not shown because the order in which adjacent pairs of each pair are considered is not important. For example, instead of considering two new pairs of values that occur by adding new values each time in succession, only each new pair of smaller coordinates is considered each time until the end of the iteration, and then the subsequent pairs are considered. Consider and then end the iteration again, so that the points in FIG. 2 are determined in the order X ₁ , X ₂ , X ₃ , X ₄ , X ₆ , X ₇ , X ₅ , X ₈ , X ₉ . Can be.

The luminous intensity I (x) of the point light source at any diffusion point 10 in the distribution W (x) reaches the diffusion point 10 under consideration through a series of different trajectories that optionally include reflections in the diffuser 3. Depends on all the rays.

The rays reaching the diffusion point 10 of the extractor 8 are classified from a qualitative point of view in the following types of trajectories.

(a) a light beam, such as light beam SX of FIG. 4, directly reaching point X of extractor 8 from light source S,

(b) a light beam, such as light beam SX of FIG. 5, which reaches point X ₀ of emission surface 5 from light source S and then reaches point X of extractor 8,

(c) From the light source S the point X ₀ of the reflective base layer 9, ie the non-diffusion point, is reached, and then the point X ₁ of the emitting surface 5 is reached, and then the point of the extractor 8. Rays, such as rays SX of FIG. 6, reaching X,

(d) light rays which alternately reach the light emitting surface 5 and the extractor 8 several times at the point of the reflective base layer 9 before reaching the diffusion point 10 of the extractor 8 from the light source S,

(e) discharged by the diffusion point 10 of the extractor 8 to reach the luminous surface 5 at an angle smaller than the critical angle θ _max , such as rays R ₃₁ and R _{32 in} FIG. 1, and then To the point of reflection base layer (9) of the extractor (8) and the light beam reaching the diffuse point (10) of the extractor (8) immediately after one or more consecutive reflections at the light emitting surface (5).

In fact, the above classification is based on the number of reflections in the diffuser 3.

The effect of the diffuser 3 wall on the luminous intensity can be sampled by introducing the following coefficients.

An absorption reflection coefficient of the luminescent surface 5 (Rif ₅ , e.g., about 0.98 for an OLF film),

The absorption reflection coefficient of the point of the reflective base layer 9 of the extractor 8 (Rif ₈ , for example about 0.98 for the side without the microprism of the OLF film, about 0.95 for the mirror),

- if the absorption spreading factor (Dif _8, for example, the white of the screen printing point of the spreading point (10) of the extractor (8) is approximately 0.80 · η Im; Here, η is the number of light that exits the diffusion point and For example, in the case of a planar extractor, it is selected as [pi] / 10, [pi] / 100, [pi] / 1000, etc. according to a predetermined precision).

The contribution to the luminous intensity I (x) of the point light source at any diffuse point 10 of the extractor 8 decreases from (a) type of light to (e) type of light due to any incident light, The number of reflections of light rays within the various types of trajectories summarized below under the letters (d) and (e) decreases with increasing.

Thus, in the first approximation, only light rays of type (a) can be considered. 3 and 4, the procedure of the method according to the invention is as follows.

As shown in block 31 of FIG. 3, the first point x ₁ (point A of FIG. 4) of the distribution W (x) of the diffusion point 10 is a ray of type (a), that is, a point in FIG. 4. It is set as the point of incidence on the extractor 8 closest to the illumination system 2 of the light beam which reaches directly to the extractor 8 from the light source 21 of the light guide lamp 1, denoted S. The first point corresponds to the end proximal to the illumination system 2 of the extractor 8, ie point A with coordinates x ₁ = 0.

On the other hand, as shown in block 33, the second point x ₂ of the distribution W (x) of the diffusion point 10 is the last point of incidence on the extractor 8 farthest from the illumination system ₂ of type (a) light ray. Is set as. This point corresponds to the end of the extractor 8 opposite the illumination system 2, ie point B with coordinates x ₂ = l.

When the luminance of the light source 21 is denoted by K, the luminance at the general point X having the coordinate x due to the type (a) light ray is represented by equation (2).                 

Here, the Pythagorean theorem has been applied to the triangle SXX 'of FIG. 4, where X' represents the projection of the point on the longitudinal axis of the light guide lamp 1.

In block 35 of FIG. 3, the coordinate x of point X of the diffuser equally illuminated by a point light source of luminous intensity I (0) arranged at point A and by a point light source of luminous intensity I (l) arranged at point B is It is represented by equation (3).

More generally, a point light source that is at luminous intensity I (x _i ) arranged at point X _i of the distribution of points W (x) and a point at luminous intensity I (x _{i + 1} ) arranged at the next adjacent point X _{i + 1} . The coordinate x of the point X which is equally illuminated by the light source is represented by equation (4).

The solution of Equation 4 may be expressed as Equation 5.                 

Or by applying equation (2) it can be as shown in equation (6).

Repeated application of the formula with the aforementioned criteria results in the desired point distribution W (x) = x ₁ , x ₂ , ..., x _n , that is, within the range of a simple assumption that the illumination of the light guide lamp 1 is formulated. The distribution of points becoming uniform can be obtained.

In order to improve the approximation, the method of the present invention, as shown in the block diagram in FIG. 7, determines at least the second distribution W ₁ (x), W ₂ (x),... Block 41), for each other type of propagation, add each second distribution W ₁ (x), W ₂ (x), ... of the points to the distribution W (x) determined above (block 40) ( Block 42) is proposed.

For example, referring to FIG. 5, a point X of the light emitting surface 5 from a light beam of type (b) according to the above classification, ie from the light source 21 (S in FIG. 5) of the light guide lamp 1. A ray reaching _zero and then reaching point X of the extractor 8 can be considered.

In this case, in the step indicated by block 31 of FIG. 3, the first point A of the distribution W ₁ (x) has a coordinate x ₁ represented by equation (7).

This is obtained by observing the light beam under consideration reflected at an angle θ _max at the end point A ₀ of the light emitting surface 5 proximate the illumination system 2.

The second point B of the distribution W ₁ (x) calculated in the step shown in block 33 of FIG. 3 has coordinates x ₂ = L relative to the distribution W (x).

The luminous intensity at point X with coordinate x can be considered as given by Equation (8).

Here, X ₀ ′ is the projection of the point X ₀ on the longitudinal axis of the light guide lamp 1. In fact, the projection of the point X on the longitudinal axis of the light guiding lamp 1 is represented by X 'and the rays X reflected from the equations of triangles SX ₀ X ₀ ', X ₀ X ₀ 'X ₀ ''and X ₀ ''XX' _{If the} intersection of ₀ X and the axis is represented by X ₀ '', then SX ₀ '= SX' / 3. In fact, it is more practical to use a distance SX ₀ 'instead SX ₀ and ignoring the length of the part X ₀ X without a significant error insertion.

The coordinates x of the point X, which are equally illuminated by the two point light sources, which are in turn considered in the iterative calculation of block 35 of FIG. 3, are of course given by Equations 3 and 4 above.

In order to further improve the approximation, referring to FIG. 6, a light beam of type (c) according to the above-mentioned classification, ie, of the extractor 8 from the light source 21 (S in FIG. 6) of the light guiding lamp 1, is used. A light beam reaching point X ₀ , point X ₁ of the emitting surface 5 and then to point X of the extractor 8 can be considered.

In this case, in the step indicated by block 31 of FIG. 3, the first point A of the distribution W ₂ (x) has a coordinate x ₁ represented by Equation (9).

This is obtained by observing the triangles A ₀ A ₁ A ₁ 'and A ₁ A ₁ ' A.

The second point B of the distribution W ₁ (x) calculated at the step indicated in block 33 of FIG. 3 is the coordinate x _B = L for the distributions W (x) and W ₁ (x).

The luminous intensity at point X with coordinate x can be assumed to be given by equation (10).

This is obtained from the equation of various triangles in which the longitudinal axis of the light guide lamp 1 is formed of the light beam under consideration.

The coordinate x of the point X, which is equally illuminated by the two point light sources considered in turn in the iterative calculation of block 35 of FIG. 3, is also given in this case by equations (3) and (4).

Generalizing the foregoing, after the light rays of type (d) of the aforementioned classification, ie the light rays from the light source 21 are reflected in the diffuser 3, ie by the light emitting surface 5 and optionally the extractor In the case of light rays reflected by (8) at least once and reaching the extractor, the luminous intensity I (x) of each point light source is multiplied by the luminous intensity K of the light source by the absorption diffusion coefficient Dif ₈ of the diffuser and the light emitting surface 5 For each reflection of, multiply by the absorption reflection coefficient Rif ₅ of the emitting surface, and for each reflection of the extractor ₈ by the absorption reflection coefficient Rif ₈ of the extractor, and from the light source S to the first reflection point X ₀ , It is given by the square of the projection along the direction of propagation.

Finally, in the case where light rays of the type (e) of the above classification are also considered, for each ray incident on the extractor 8 at diffusion point 10, the luminous intensity I (x) of the point light source is absorbed and diffused by the extractor. Multiply by the coefficient Dif ₈ .

If the light guide lamp 1 intended to insert the extractor comprises two lighting systems 2, 2a that reflect each other, it takes into account the two light sources 21, 21a during all previous steps of the method of the invention. It is possible.

However, as shown in the block diagram in Fig. 8, according to the method of the present invention, when two lighting systems 21 and 21a are installed (decision block 51), the point determined as described above (block 50) Determine the second distribution W '= (l-x _n , ... L-x ₂ , l-x ₁ ) of the points reflecting on the distribution W (x) (block 52) and the second distribution W' = of the points It is preferable to provide so that (l-x _n , ... l-x ₂ , l-x ₁ ) is added to the point distribution W = (x ₁ , x ₂ , ... x _n ).

Because of the symmetry of the light guide lamp 1, the second distribution W ′ of the points is adapted to provide uniform illumination in the light guide lamp 1 comprising a single illumination system 21a. Moreover, it is readily understood that the illumination attributable to the illumination system 21 when there is a point of the second distribution W 'of points is the same as the illumination attributable to the illumination system 21a when there is a point of the first distribution W of the point. Can be.

When the distribution W (x) of the point along the main propagation direction x is obtained, the two-dimensional distribution of the diffusion point 10 on the reflective base layer 9 of the extractor 8 gives the distribution W (x) of the point. It can be obtained by simply repeating at constant interval ΔY along the direction y perpendicular to the main propagation direction x. This is shown in the left path in the block diagram of FIG. 9, where, after determining the distribution of points W (x) in block 60, the distribution of points W at block 61 and the current value of coordinate y that increments the coordinate y ( Enter cycle, including block 62, setting x, y) equal to the distribution of points W (x).

Thus, as shown in FIG. 10, the extractor 8 exhibits a distribution of the stripe of the diffusion point 10, the illumination of which is sufficiently uniform in a plane perpendicular to the main propagation direction x.

10, it can be seen that the distribution of the diffusion point 10 of the extractor 8 is symmetric about the intermediate axis perpendicular to the main propagation direction x. Extractors provided with this symmetry are particularly suitable for use in light guide lamps 1 having two lighting systems 2, 2a.

As in the case described above, when the distribution of points is determined by applying the above method, adjacent diffusion points 10 of the point distribution extend from each end of the extractor 8 to the intermediate axis AA perpendicular to the main propagation direction x. And the extractor provides uniform illumination along the main propagation direction (x).

Similarly, if the extractor 8 is to be used in a light guiding lamp 1 having only a single illumination system 2, the adjacent diffusion point 10 is opposite from the first light incoming end to which the illumination system 2 is to be coupled. It is kept at a reduced distance along the main propagation direction x to the end. This extractor is represented by an extractor 8 'enclosed in dashed lines in FIG.

As another example, the distribution of points W (x) may be alternating forward and backward in the main propagation direction x during the iteration along the direction y. In this case, the diffusion points 10 on the base layer 9 of the extractor 8 are arranged in a rhombus, as shown in FIG. This has the advantage of reducing the distance between the diffusion points under the minimum distance imposed by the physical implementation of the extractor.

This is shown in the right path in the block diagram of FIG. 9, and after determining the distribution of points W (x) at block 60, the distribution of points W (x, y) at block 61 and the current value of coordinate y which increments the coordinate y Enter a cycle containing block 63 which sets equal to the distribution of points W (x ± Δx). This should be understood as meaning that the + and-signs are used alternately in successive iterations.

Preferably, the stagger interval Δx is equal to the repetition interval Δy of the distribution W (x).

In order to avoid obtaining a distribution W (x) with a higher accuracy than the limit of the physical implementation of the extractor, indicating a distance greater than the minimum distance D _min from immediately adjacent points to impose the condition of equation (11). It is good to reject the points from the point distribution W (x).

Similarly, the following conditions will be imposed upon determining the two-dimensional distribution W (x, y) as described above.

The minimum distance D _min corresponds to the resolution obtainable, for example, via silk screen printing.

The condition of Equation 11 may also be imposed upon the calculation of the coordinates of a point that is equally illuminated by two point light sources within adjacent points of the distribution according to Equations 3 and 4, but in some cases its effectiveness After any optional step of adding this second distribution, i.e., after block 42 of FIG. 7 and / or after block 53 of FIG.

Another procedure of determining the distribution of the diffusion point 10 of the light extractor 8, in particular the distribution where the light emitted by the light guide lamp 1 should be as uniform as possible is as follows.

First, the useful surface of the extractor 8 is characterized by the diffusion point density variables D ₁ , D ₂ ,..., For each interval along the main propagation direction x. , Divided into predetermined small intervals defining D _n .

Similarly, the luminescent surface 5 has luminous intensity parameters N ₁ , N ₂ ,... For each interval along the main propagation direction x. , Divided into predetermined small intervals defining N _m .

Then, the luminous intensity parameters N ₁ , N ₂ ,... , The value of N _m is, for example, the diffusion point density variables D ₁ , D ₂ ,. , As a function of D _n .

Finally, the diffusion point density variables D ₁ , D ₂ ,... Of the extractor 8. , The values of D _n are the luminance parameters N ₁ , N ₂ ,..., Of each interval of the emitting surface 5. , All of the intervals of brightness variable, in particular the light emission surface (5) to provide a predetermined value of _{N m N 1, N 2,} ... , N _m are calculated to equalize each other.

Similar to the first method described above, the luminance variables N ₁ , N ₂ ,. , N _m can be obtained as follows.

First, the light projected by the illumination systems 2, 2a or by each of the illumination systems is split into a finite number of rays, each emitted at a separate angle. For example, the number of light beams to be considered may be selected as 2π / 10, 2π / 100, 2π / 1000, etc., depending on the desired accuracy.

Each emitted light is given an initial luminance value, which can be set to the value L = 1 for simplicity.

Then, along the path of each ray, the luminous intensity variables N ₁ , N ₂ ,... , N _m is incremented by an angle greater than its critical angle θ _max with respect to the main propagation direction, i.e. by the value of the final luminous intensity L 'of each light beam incident therein, so as to be transmitted out of the light guide lamp 1. .

The light intensity value of each light ray changes according to the following criteria.

At each incidence of the ray within the interval of the extractor 8 the ray can be reflected or diffused depending on whether it is incident on the diffusion point 10 or on the reflection point 9. The diffusion point density D _i of the spacing under consideration can be considered to indicate the probability that the light beam will reflect or diffuse.

Therefore, when the light beam is reflected, the light intensity value of the reflected light ray is obtained by multiplying the light intensity value of the incident light ray by the absorption reflection coefficient Rif ₈ of the extractor, and when the light ray is diffused, the light intensity value of each diffused light ray is The luminous intensity value is obtained by multiplying the absorption diffusion coefficient Dif ₈ of the extractor.

Upon incidence on the light emitting surface 5 at an angle smaller than its critical angle θ _max with respect to the main propagation direction, the luminous intensity value of the reflected ray is obtained by multiplying the luminous intensity value of the incident ray by the absorption reflection coefficient Rif ₅ of the emitting surface. Lose.

Luminous intensity variables N ₁ , N ₂ ,. By equalizing the representation of N _{m with} the respective desired values, in particular by equalizing the values with each other, an equalization system is obtained, the unknown values of which are obtained by the diffusion point density D ₁ , D ₂ , … , D _n .

Such a system can be solved mathematically using, for example, numerical methods. However, since the mathematical solution is not rapid, the following iterative method can be used.

Diffusion point density variables D ₁ , D ₂ ,. , Values of D _n and luminous intensity variables N ₁ , N ₂ ,. , Initially set the value of N _m to 0.

At each iteration, the luminous intensity parameters N ₁ , N ₂ ,..., Of each interval of the light emitting surface 5 represented as described above. , The value of N _m is the diffusion point density variable D ₁ , D ₂ ,... , Based on the current value of D _n , ie based on the current probability that the light incident on the extractor 8 will be reflected or diffused.

Then, at each iteration, the diffusion point density variables D ₁ , D ₂ ,... Of the extractor 8. , The values of D _n are each individually incremented by a sufficiently small amount.

The repetition consists of luminous intensity variables N ₁ , N ₂ ,. , When the values of N _m are at the desired values, in particular the luminous intensity variables N ₁ , N ₂ ,... , Ends when the values of N _m become equal to each other.

For example, in an extractor 8 intended for use in a light guide lamp 1 having two lighting systems 2, 2a, the diffusion point density parameters D ₁ , D ₂ ,. , The increment of the values of D _n can occur starting from the center of the extractor 8.

Similar to the first method described above, the distribution of the diffusion points along the main propagation direction, once obtained, can be repeated at regular intervals Δy according to the direction y perpendicular to that direction, and optionally It is possible to alternately distribute the points forward and backward in the main propagation direction by the minimum distance Δx.

Also, similar to the first method described above, this may be suitable for rejecting from the distribution of points points that represent a distance greater than a preset minimum distance D _min from immediately adjacent points.

12 to 14 are schematic diagrams showing another embodiment of a light guiding lamp including a light extractor according to the present invention.

In the light guiding lamp 121 shown in FIG. 12, both the light extractor 128 and the light emitting surface 125 are curved with a concave surface toward the longitudinal axis of the diffuser 123. As shown in FIG. In particular, each of these cross sections may be semi-circular, semi-elliptical, semi-parabolic, parabolic or may follow a higher-order curve. Projection system 122, or in each of the two projection systems 122, 122a, includes respective point light sources 1221, 1221a.

In the light guiding lamp 131 shown in FIG. 13, the light emitting surface 135 is planar, and the light extractor 138 is curved toward the longitudinal axis of the diffuser 133, in particular semi-circular, semi-elliptic, semi-parabolic, It is curved along a parabolic cross section or along a higher order curved surface. As another example, it is also possible to provide a planar extractor and in particular a light emitting surface curved along the longitudinal axis of the diffuser 133 along a semicircular, semi-elliptic, semiparabolic, parabolic cross section or along a higher order surface. Also in this case, the projection system 132, or in each of the two projection systems 132, 132a, includes respective point light sources 1321, 1321a.

Finally, in the light guiding lamp 141 shown in FIG. 14, the light extractor 148 and the light emitting surface 145 are both in particular along a semicircular, semi-elliptic, semiparabolic, parabolic cross section or along a higher order curve. Although curved, they are arranged such that their concave surfaces face in the same direction. That is, the light emitting surface 145 is arranged inside or outside the extractor 148 such that the cross section of the light guiding lamp 141 is horseshoe shaped. In this case, the projection system 142, or in each of the two projection systems 142, 142a, comprises respective elongated tubular light sources 1421, 1421a.

The method for determining the distribution of diffusion points described with reference to the lamp having the rhombus configuration shown in FIG. 1 is also applicable to other configurations of the light guiding lamp, and that such changes can be made within the capabilities of those skilled in the art. You should know

In addition, the first method described above is particularly suitable for performing by an electronic computer.

Figure 15 shows a block diagram illustrating a particularly preferred embodiment of a computer program comprising program code means suitable for carrying out each step of the method when the program is run on a computer.

The description of the code means relating to the various steps of the method is omitted below because such code means are considered to be within the capabilities of the associated programmer, such as cycle problems, iterative routine calls, and the application of numerical formulas. to be. The distribution of points W (x) or the respective second distributions Wi (x), W '(x) may be stored, for example, in a one-dimensional array or list. The management of repetitive calls in the block diagram of FIG. 3, which must consider all pairs of values, can result in managing pointers to a matrix (index) or through a queue (FIFO) or stack (LIFO) structure.

As shown in block 70, the computer program includes means, such as a form, for receiving one or more of the following parameters as input.

The critical angle θ _max of the light emitting surface 5;

The shape and size of the extractor 8; The shape can be selected from a list including, for example, rectangles having various shapes, ie semicircular cross section, semi-elliptical cross section, semiparabolic cross section, parabolic cross section.

The shape and size of the light emitting surface 5; The shape can be selected from a list including, for example, rectangles having various shapes, ie semicircular cross section, semi-elliptical cross section, semiparabolic cross section, parabolic cross section.

The maximum distance of the extractor 8 from the light emitting surface 5;

The number, type, brightness K and characteristics of the light sources 21, 21a of the lighting system 2;

The minimum distance D _min between the points in the point distribution;

The absorption reflection coefficient, Rif ₈ , of the extractor;

Absorption diffusion coefficient of extractor (Dif ₈ );

An absorption reflection coefficient (Rif ₅ ) of the light emitting surface;

The maximum number of continuous reflections on the light emitting surface 5 and the extractor 8 under consideration.

In this regard, respective default values can be provided. Furthermore, the input values are acceptable, in particular their values are positive numbers, the size of the extractor 8 and the size of the light emitting surface 5 preferably match each other, the length of the main propagation direction ( 1) and means for controlling that the ratio of the distance h between the extractor and the light emitting surface is 20. In fact, the ratio is preferred because in this method light propagates with a sufficiently low number of incidences and hence low losses.                 

The entered values may be stored in a file as shown in block 71 and retrieved from the file to change or repeat the process as shown in block 72.

Next, in block 74, the program performs various steps of the method of the present invention, such as receiving a start signal, as shown in block 74. For example, the start signal may be a pressing of a button of a keyboard, a graphic interface, or other device.

Then, at block 75, the program generates one or more outputs, as shown at block 75 ', among those described below.

The coordinates of the points of distribution W (x) in the spreadsheet, for example,

The percentage density of the points in the distribution at the base interval,

A report of pre-set parameters, eg as a spreadsheet,

A graphical representation of the point distribution W (x) or W (x, y), for example with a graph of linear functions representing a gradual increase in points,

The geometry of each lighting system of the light guide lamp to which the extractor is to be installed, as a function of the preset mean distance h between the extractor 8 and the emitting surface 5 and the predetermined critical angle θ _max of the emitting surface 5 Shape, in particular the focus δ of the reflective parabolic surfaces 22, 22a.

Also preferably, at block 76, the program generates an export output as follows.

A file 76 'of points of distribution W (x) of the format readable in a printing press, in particular a silk screen printing press.

Indeed, such computer programs can be distributed over information networks, especially the Internet, and can be implemented in computer readable means such as floppy disks, CD-ROMs, CD-Rs, and the like.

Those skilled in the art can make various changes, modifications, substitutions and integrations to the above-described embodiments without departing from the scope of the invention as defined in the following claims.

In particular, a special "dotted line" useful surface consisting of diffusion points and compensating reflection points may also be useful for three-dimensional body extractors intended to be used in the axial position of the light guide lamp.

In particular, it should be appreciated that the diffusion point and reflection points may be applied in accordance with each predetermined compensation distribution on the intermediate substrate or by applying the reflection points on the diffusion base layer. Thus, in this specification and claims, any citation for "point of reflective base layer" should be interpreted as equivalent to the expression of "reflection point".

In addition, instead of a lighting system having a reflective parabolic light source or a fluorescent light source, a planar lighting system composed of a plurality of LEDs may be used in various embodiments.

Those skilled in the art will understand that although various materials can be used as the reflective surface and the light emitting surface, it is advantageous to use the multilayer optical film disclosed in the aforementioned US Pat. No. 5,882,774.

Claims (35)

An illumination system (2; 122; 132) suitable for projecting light from the light sources (21; 1221; 1321; 1421) to the diffuser (3; 123; 133; 143) at an angle smaller than a predetermined critical angle (θ _max ); In a diffuser (3; 123; 133; 143) for a light guiding lamp (1; 121; 131; 141) having a 142, it transmits light propagating at an angle smaller than the threshold angle (theta) _max and the threshold angle (θ). useful surface of light extractor 8; 128; 138; 148, which is coupled to a light emitting surface 5; 125; 135; 145 which internally reflects light propagating at an angle greater than _max ; 9)), in the method for determining the distribution W (x) along the main propagation direction x of the diffusion point 10, (a) the light extractor 8 closest to the illumination system 2; 122; 132; 142 of the light beam propagating the first point A, x ₁ of the distribution W (x) along a trajectory of a preselected type. 128; 138; 148 as the last point of incidence on 148; (b) the light extractor farthest from the illumination system 2 (122; 132; 142) of the beam propagating the second point B, x ₂ of the distribution W (x) along a trajectory of a preselected type ( 8; 128; 138; 148 as the last incidence point; (c) For each point (x _i ) of the point distribution, the new point (X, x) of the distribution is a first point light source arranged at a preselected point (x _i ) of the distribution and the next neighbor of the distribution. Iteratively determining as a point of a light extractor 8; 128; 138; 148 that is equally illuminated by a second point light source arranged at point x _{i + 1} , the intensity I of the point light source I (x)) is determined as a function of the intensity K of the light source and the characteristic distance of the trajectory of the preselected type. delete delete delete delete delete delete delete delete delete delete delete delete delete At least suitable for projecting light from light sources 21, 21a; 1221, 1221a; 1321, 1321a; 1421, 1421a to diffuser 3; 123; 133; 143 at an angle smaller than a predetermined critical angle θ _max . In the diffuser (3; 123; 133; 143) for a light guiding lamp (1; 121; 131; 141) with one illumination system (2, 2a; 122, 122a; 132, 132a; 142, 142a), the critical angle transmitted through the light propagating to a smaller angle than that (θ _max) and the critical angle of the light emission surface (5; 125; 135; 145) for further reflecting the rays internally propagated to a large angle than that (θ _max) the light coupled to the extractor On a useful surface (reflecting elsewhere 9) of (8; 128; 138; 148), a method for determining the distribution W (x) along the main propagation direction x of the diffusion point 10; In (a) Define the diffusion point density parameters D ₁ , D ₂ ,... D _n for each interval of a preselected length along the main direction of propagation (x) of the useful surfaces of the extractors 8; 128; 138; 148. To do that, (b) defining a luminous intensity parameter (N ₁ , N ₂ ,... N _m ) for each interval of a preselected length along the main propagation direction (x) of the emitting surface (5; 125; 135; 145), (c) The value of the luminosity variables N ₁ , N ₂ ,... N _m of each interval of the light emitting surfaces 5; 125; 135; 145 is determined by the diffusion point density parameters of the extractors 8; 128; 138; 148. a method of expressing as a function of _{D 1, D 2, ... D} n), (d) the values of the diffusion point density variables D ₁ , D ₂ ,... D _{n of the} extractors 8; 128; 138; 148 are determined by the luminance parameters of all intervals of the emitting surface 5; 125; 135; Calculating to be equal to the value of N ₁ , N ₂ ,... N _m ). delete delete delete delete delete In a light extractor (8; 128; 138; 148) for a light guide lamp (1) having a useful surface comprising a predetermined distribution of diffusion points (10) and a compensation distribution of reflection points (9), The distribution of said diffusion points (10) is that obtained by the method of claim 1 or the method of claim 15. The light extractor of claim 21, wherein the useful surface comprises a reflective base layer (9) and a predetermined distribution of diffusion points (10) on the reflective base layer (9). delete delete delete delete delete delete delete delete delete delete delete In the method of manufacturing the light extractor (8; 128; 138; 148), (a) providing a reflective base layer 9; (b) silk screen printing the diffusion points 10 on the reflective base layer 9 according to the distribution of points W (x) obtained according to the method of claim 1 or the method of claim 15. Way. delete

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