FR3054643A1 - LIGHTING DEVICE. - Google Patents

Abstract

Lighting device for air-conditioned cabinets or development cabinets comprising at least one light source (26) installed between a plate (24) made of a material transparent to light and a plate (22) whose side facing the light source (26) is at least partially reflective. A pattern of perforations (28, 30, 30 ', 30' ', 30' ') of non-transparent material is provided on the transparent material plate (24), and the pattern side of the perforations (28, 30, 30') , 30 '', 30 "') facing the light source (26) is reflective.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders)

©) National registration number

054 643

52075

COURBEVOIE

©) Int Cl ⁸ : F21 V13 / 10 (2017.01)

PATENT INVENTION APPLICATION

A1

©) Date of filing: 01.04.09. © Applicant (s): BINDER GMBH— DE. (30) Priority: 02.04.08 DE 102008017118.2. ©) Inventor (s): BUTTERHOF BERND. ©) Date of public availability of the request: 02.02.18 Bulletin 18/05. (56) List of documents cited in the report preliminary research: The latter was not established on the date of publication of the request. (© References to other national documents ©) Holder (s): BINDER GMBH. related: ©) Extension request (s): @) Agent (s): CABINET HERRBURGER.

104) LIGHTING DEVICE.

FR 3 054 643 - A1 _ Lighting device for air-conditioned cabinets or development cabinets comprising at least one light source (26) installed between a plate (24) made of a material transparent to light and a plate (22) of which the side facing the light source (26) is at least partially reflective.

A pattern of the perforations (28, 30, 30 ', 30, 30 “j of non-transparent material is provided on the plate (24) of transparent material, and the side of the pattern of the perforations (28, 30, 30', 30, 30 “j facing the light source (26) is reflective.

i

Field of the invention

The present invention relates to a lighting device for air conditioning cabinets or development cabinets.

State of the art

In particular in air-conditioned cabinets or development cabinets, lighting devices are used which include at least one light source, for example fluorescent tubes, incandescent lamps or halogen lamps to make stability checks of various products such as for example pharmaceuticals, or for plant development or cell culture. To obtain reproducible results it is important that the products also called samples are exposed under identical conditions. Due to the short distances between the lighting device in the cabinet and samples, in the case of air-conditioned cabinets or known development cabinets, the light intensity is not homogeneous on the support surface receiving the samples . A non-homogeneous distribution of the light intensity leads on the one hand to non-reproducible control conditions and on the other hand it can also result in a non-homogeneous distribution of the temperature which can also lead to test results not comparable between samples.

Purpose of the invention

The present invention aims to develop a lighting device in particular for air-conditioned cabinets or development cabinets for obtaining a homogeneous distribution of the light intensity. The object of the invention is also to develop a method for determining a pattern of the perforations making it possible to obtain a distribution of the light intensity of a certain arrangement of light source above a given support surface in order to homogenize this distribution. .

Presentation and advantages of the invention

To this end, the invention relates to a lighting device for air-conditioned cabinets or development cabinets comprising at least one light source installed between a plate made of a material transparent to light and a plate whose side facing the light source is at least partially reflective, characterized by

a pattern of the perforations in non-transparent material on the plate in transparent material, and

- the side of the perforation pattern facing the light source is reflective.

The invention also relates to a method for determining a pattern of the perforations to homogenize the distribution of the light intensity of a certain light source according to a determined adjustment surface, comprising the following steps:

- determination of the distribution of the light intensity of the light source device on the support surface,

- determination of an average light intensity,

- determination of the zones of the distribution of the light intensity and determination of the attenuation of the light intensity in each of the zones to have an average light intensity,

- determination of the fraction of the corresponding area of the surface of a transparent plate installed between the light source device and the support surface, which must be covered with a material opaque to light to obtain the desired attenuation,

- Determination of the pattern of the perforations so as to install it in the area of the surface of the material not transparent to light and release of the perforations to obtain the determined ratio of closed surface and surface of the perforations.

The lighting device according to the invention comprises at least one light source between a plate made of transparent material and a plate whose side facing the light source is at least partly reflective and the plate made of transparent material bears the pattern of the perforations ( or holes) of non-transparent material and the side of the pattern of the perforations facing the light source is reflective.

The transparent material plate serves as a support for the pattern of the perforations in non-transparent material whose side facing the light source is reflective so that part of the light passes directly through the perforations of the pattern to reach the samples which are directly in below the lighting device and that part of the light is however reflected by the reflective layer of the pattern of the perforations to be reflected by the reflective plate installed behind the light source and then pass through the perforations of the pattern to reach the samples or be reflected again by the pattern of the perforations. The light reflected by the pattern of the perforations, first of all retained because arriving from a different angle from that of the light which comes directly on the pattern of the perforations, falls on the transparent plate. This light is available in another place to increase the intensity so that overall the distribution of the light intensity is homogenized. In addition, the transparent material plate makes it possible to reduce the thermal influence of the light source on the samples, thereby improving the comparability of the test results.

The pattern of the perforations is preferably optimized so that the maxima of the distribution of the light intensity can be reduced without a pattern of the perforations and so that the distribution of the light intensity is thus generally homogenized.

In a particularly preferred manner, the pattern of the perforations of the distribution of the light intensity of the light source corresponds to an optimal homogenization of the distribution of the light intensity after the light has passed through the pattern of the perforations.

Particularly good homogenization is obtained, in particular if preferably the pattern of the perforations corresponds to the distribution of the light intensity of the light source so that at places of high light intensity, the ratio between the closed surface and the surface of the perforations of the pattern is high and that at places of lower light intensity, the ratio between the closed surface and the surface provided with the orifices of the perforations is low. Preferably, in particular the ratio between the closed surface and the surface of the perforations of the pattern corresponds to the ratio according to which the light intensity must be attenuated in this area.

In a particularly preferred manner, the pattern of the perforations is printed on the plate made of transparent material, in particular on the side of the plate facing the light source made of non-transparent material is obtained in particular by a screen printing process so that the lighting device according to the invention can be produced in a particularly economical and simple manner.

To have a good homogenization of the distribution of the light intensity, the pattern of the perforations preferably includes a partial zone in which the perforations are distributed according to a network structure.

To better homogenize the distribution of the light intensity, the pattern of the perforations preferably comprises at least a first partial zone in which there are perforations distributed according to a network pitch substantially double the diameter of the perforations in the direction of the network pitch . In a particularly preferred manner, to further improve the homogenization of the distribution of the light intensity in the first partial area, the perforations are distributed both in the direction of the X axis and in the direction of the Y axis according to the network step or period which is substantially double the diameter of the perforations in the direction of this period or no network.

Preferably, the pattern of the perforations comprises at least a second partial zone in which the perforations are distributed in a network pitch which corresponds substantially to 1.2 to 1.5 times and in particular to approximately 4/3 times the diameter perforations in the direction of the network pitch. In a particularly preferred manner, in this second partial zone, the perforations are distributed both along the X axis and along the Y axis with the weft pitch which corresponds to approximately 1.2 to 1.5 times and to in particular 4/3 times the diameter of the perforations in the direction of the grating pitch.

In a particularly preferred manner, the pattern of the perforations comprises at least a third partial zone in which the perforations are distributed along the Y axis according to a frame period which corresponds substantially to 1.2 to 1.5 times and in particular to approximately 4/3 times the diameter of the perforations in the direction of this network pitch and whose perforations in the direction of the Y axis are distributed over a frame period substantially double the diameter of the perforations in the direction of this network pitch.

The homogenization of the distribution of the light intensity will be particularly good if the pattern of the perforations comprises a first substantially square partial area, two third substantially triangular partial areas, adjacent to two opposite sides of the first partial area, two second partial areas of substantially trapezoidal shape, adjacent to the other opposite end faces, of the first partial area and four second partial areas of substantially triangular shape adjacent to the branches not turned towards the first partial area and belonging to the third partial areas of triangular shape.

A particularly advantageous embodiment of the invention comprises a transparent glass plate which allows economical manufacture and low attenuation of the light intensity. A glass plate also has the advantage that if light is used at wavelengths in the visible range, these are not modified by their passage through the glass plate. With UV light, special glass plates can be used with a corresponding transmission characteristic which also leaves the wavelengths of light unchanged.

According to one embodiment of the invention, the transparent material plate is placed in front of the light sources already installed in the cabinets. The reflective plate is preferably then formed by the interior covering of the cabinets. According to a preferred embodiment, the plate made of non-transparent material and the plate whose side facing the light source are made at least partially reflecting while being part of the housing in which the light source is installed, so that the 'cabinet constituted by this box can be easily equipped with the lighting device according to the invention.

To maximize the overall light intensity exiting the housing, the latter preferably comprises a partition which, independently of the surface formed by the plate of transparent material, is reflective.

In a particularly preferred manner, a lighting device according to the invention is used in an air-conditioned cabinet or in a development cabinet.

The method according to the invention for determining a pattern of the perforations in order to homogenize the distribution of the light intensity of a certain light source device on a given actuation surface, will be carried out by applying the following steps:

First, the distribution of the light intensity of the light source device over the positioning surface is determined.

Next, an average light intensity is predefined, which must prevail mainly over the entire width of the support surface. In addition, the areas of the light intensity distribution are determined to determine how much the light intensity must be attenuated in each of the areas to obtain the average light intensity. Then we determine the part of the corresponding area of the surface that must be covered with a transparent plate installed between the light source device and the adjustment surface covered with an opaque material to obtain the desired attenuation. Finally, the pattern of the perforations to be produced is obtained on the transparent plate, made of opaque material in that in the area of the surface, opaque material is applied and the orifices are released to obtain the determined part of the surface closed relative to that of the orifices.

The perforation pattern is preferably produced so that at places of high light intensity, the ratio between closed surface and perforation surface of the pattern of perforations is higher than at places of low light intensity, the ratio between closed surface and the area of the perforations of the pattern of the perforations is smaller to finally obtain a homogeneous distribution of the light intensity over the entire actuation surface.

To avoid strong shading or projection of shade, the orifices are preferably distributed regularly over the corresponding area, for example according to network structure provisions or symmetrical arrangements.

Drawings

The present invention will be described below in more detail with the aid of exemplary embodiments shown in the accompanying drawings in which:

FIG. 1 is a diagrammatic section of the first embodiment of a lighting device according to the invention,

FIG. 2 is a schematic view of an air-conditioned cabinet equipped with a lighting device according to FIG. 1,

FIG. 3 is a top view of an exemplary embodiment of a first pattern of perforations according to the invention,

FIG. 4 is a top view of a second exemplary embodiment of a pattern of perforations according to the invention,

FIG. 5 is a top view of a third embodiment of a pattern of perforations according to the invention, and

- Figure 6 is a top view of a fourth embodiment of a pattern of perforations according to the invention.

Description of embodiments of the invention

FIG. 1 is a section through a housing 20 fitted with a light source 26 produced for example by fluorescent tubes. As the light source 26, incandescent bulbs, halogen lamps or similar light sources can also be used. A front face of the housing 20 is constituted by a plate 24 made of transparent material, for example a glass plate, while the other parts of the housing are made of any material. At least the back rear side of the housing opposite the front face is either made in the form of a plate, the side facing the light source is at least partly reflective or it has on the side facing the light source, a plate 22 whose side facing the light source is at least partly reflective.

The plate 24 made of transparent material has a pattern of perforations 28 made of a non-transparent material which is, for example, printed on one face of the plate 24, for example on the inner face of the plate 24 facing the light source. Printing can be done for example by screen printing. The printing process generally prints the pattern of the perforations 28 in general in several layers, on the one hand to provide greater coverage and on the other hand to allow strong reflection on the side facing the light source. Preferably, the pattern of the perforations 28 consists of several layers of material. At least one of the layers of material has a high opacity and the side of the pattern of the perforations 28 facing the light source is produced in a layer with high reflection.

The pattern of the perforations 28 thus comprises a large number of perforations or holes 29 allowing the direct passage of the light emitted by the light source 26 through the transparent plate 26 of the housing 20. Part of the light from the light source 26 reflected is first of all returned by the reflecting face of the pattern of the perforations 28 inside the housing 20. Then this light is notably reflected again by the reflecting plate 22 in the direction of the transparent plate 24 or at least part of the light thus reflected can then leave the housing 20 through the perforations 29 of the perforation pattern 28. A portion of the light reflected a first time is, if necessary again reflected on the perforation pattern 28 to be returned inside of the housing 20.

Overall, the reflection at the level of the pattern of the perforations 28 and the consecutive reflection on at least part of the interior wall of the housing 20 homogenize the distribution of the light intensity of the light leaving the housing 20 through the transparent plate 24.

As shown in FIG. 2, the box 20 can for example be installed in an air-conditioned cabinet 10 so that it is above a support surface 15 of the air-conditioned cabinet 10 and this so that the plate 24 transparent is turned towards the support surface 26 and thus allows the support surface 15 to be illuminated by the light source 26 installed in the housing 20 and the transparent plate 24. As the plate 24 transparent to light carries the pattern perforations 28, a uniform distribution of the light intensity is obtained on the support surface 15; thus, regardless of the location where a sample to be lit is placed on the support surface 15, there will be light conditions and therefore comparable test conditions.

The design of the perforation pattern can be very different and will often be determined empirically depending on the devices, especially air-conditioned cabinets. For this it is important on the one hand that the fraction of the non-transparent surface of the pattern of the perforations is as small as possible to allow as high a light output as possible. On the other hand, it is important that the pattern of the perforations allows as optimal a homogenization as possible of the distribution of the light intensity emitted by the light source 26 or a set of several light sources 26. The production of the perforations can take different forms , for example round, oval, rectangular, square, star, diamond or other suitable shapes. The arrangement of the perforations in the perforation pattern can take different developments. In general, the perforations or holes are provided at least in a partial area of the pattern according to a network structure; the pitch (or period) of the network in two perpendicular directions, in particular in the X direction of the X axis and in the Y direction of the Y axis may be different or identical.

To determine an appropriate pattern of perforations for a certain arrangement of light sources, one generally proceeds by first determining the distribution of the light intensity of the light source or of the arrangement of several light sources on the support surface in using appropriate sensors. Next, the average light intensity to be obtained is determined over the entire support surface. We define zones of light intensity distribution and we determine how much we need to reduce the light intensity distribution in each of the zones to obtain the average light intensity. Then we determine the part of the surface of the transparent plate that must be covered with non-transparent material to obtain the desired attenuation. This part corresponds to the ratio between the closed surface and the surface of the perforations or holes in the area of the pattern. In particular, the pattern of the perforations is produced so that at the places where the strongest light intensity occurs, the rap3054643 portο port between the closed surface and the surface of the perforations of the pattern is high and at the places of low light intensity, the ratio between the closed surface and the surface of the perforations of the pattern is low to more strongly attenuate the light intensity in the zones in which reigns a significant light intensity compared to an zone in which reigns a weak light intensity so as to obtain a homogeneous light intensity extending over the entire surface. The perforations or holes are preferably distributed regularly in the corresponding zone, for example according to a network structure or symmetrical arrangements. The shape of the perforations or orifices can also be adapted preferentially to obtain a good homogenization of the distribution of the light intensity.

FIG. 3 is a plan view of an exemplary embodiment of a pattern of the perforations 30 according to the invention. This pattern shown can be printed on a glass plate, for example by a screen printing process; then the glass plate is placed in the light beam emitted by a light source and the sample to be irradiated, for example in an air-conditioned cabinet or a development cabinet.

The pattern of the perforations 30 has a first substantially square partial area 40 in which there are perforations 42 also of substantially square shape distributed both in the direction X of the axis X and in the direction Y of the axis Y perpendicular to the previous, with an L1 network pitch; the network or frame pitch L1 is substantially double the diameter of the perforations 42, that is to say the length or the width of the perforations 42 in the direction of the network pitch. Overall, the perforations 42 are arranged in a network structure in the first partial area 40.

On two front faces or opposite sides of the first partial area 40 there is each time a second partial area 50 of substantially trapezoidal shape in which there are also substantially square perforations 52, distributed in a network structure. The perforations or holes 52 are distributed both in the X direction of the X axis and in the Y direction of the Y axis but with a weft pitch L2 which corresponds substantially to 1.2 up to 1.5 times and notam3054643 lie about 4/3 times the diameter of the perforations 52, that is to say the length or the width of the perforations 52, in the direction of the X axis or of the Y axis.

On the two front faces or sides which remain of the first partial zone 40 there are two third partial zones 60 substantially triangular installed in an adjacent manner. The perforations 62 of this third partial area are distributed along a network structure. The perforations or holes 62 have a substantially rectangular shape and in the direction X of the axis X they have a length which corresponds to the length of the perforations 52 of the second partial area 50 while in the direction Y of the axis Y they are a width which corresponds substantially to the width of the perforations 42 of the first partial area 40. The perforations or holes 62 are distributed in the direction X of the axis X according to a network pitch L2 which corresponds substantially to 1.2 up to 1.5 times and in particular approximately 4/3 times the length of the perforations 62 in the X direction of the X axis or in the direction of the network pitch L2; on the other hand the perforations 62 in the Y direction of the Y axis are distributed along the network pitch L1 which is twice the width of the perforations 62 in the Y direction of the Y axis which corresponds to the direction of the network pitch L1 .

The branches of the third triangular partial zones 60 not turned towards the first partial zone 40 have adjacent each time four other second partial zones 50 of substantially triangular shape and which also have perforations 52 of the same dimension as the perforations 52 of the second zone partial 50 adjacent to the front faces or sides; in these second partial zones 50, the perforations 52 are arranged both in the direction X of the axis X and in the direction Y of the axis Y according to a network pitch equal to L2; this pitch corresponds substantially to 1.2 to 1.5 and in particular approximately 4/3 times the width of the perforations 52 in the direction of the corresponding X, Y axes.

FIG. 4 shows a plan view of another exemplary embodiment of a pattern of the perforations 30 ′ according to the invention. The pattern of the perforations 30 ′ differs from the previous 30 in FIG. 3 mainly in that the third partial areas 60 are not trian3054643 gular but substantially trapezoidal in shape and the first partial area 40 with the adjacent third partial areas 60 are located in a second partial area 50 which has a substantially hexagonal outer contour.

The pattern of the perforations 30 thus produced allows good homogenization of an elongated light source or of an arrangement of light sources, for example the homogenization of the light emitted by several fluorescent tubes installed in parallel.

The distribution of the light intensity of an incandescent lamp or an isolated light source, of substantially point shape, is mainly rotationally symmetrical and decreases as the distance from the light source increases. To have as good a homogenization as possible of the distribution of the light intensity one can use a pattern of perforations 30 ”according to figure 5. The pattern of perforations 30” represented, corresponds to circular 32 ”perforations installed in concentric circles . The diameter of the 32 ”holes or holes increases with the diameter of the concentric circles. Overall we will have a symmetrical 30 ”perforation pattern in rotation. At the center of the 30 ”perforation pattern, which is directly below the light source, there is the highest light intensity so that the strongest light intensity has to be attenuated. This is done by increasing the ratio between the closed surface of the 30 ”perforation pattern and the surface of the 52” perforations and in particular by a smaller diameter of the 52 ”perforations vis-à-vis the outside area of the 30” hole pattern. in which the light intensity of the light source is already attenuated, which makes it possible to achieve a lower attenuation of the light; this is obtained by a smaller ratio between the closed surface of the pattern of the perforations 30 "and the surface of the perforations or holes 52" and in particular by a larger diameter of the perforations 52 ". Each of the 52 ”concentric perforation circles is thus located in an area for which, separately, the necessary attenuation of the intensity of the light source has been determined and thus the ratio between the closed surface of the perforation pattern and the surface of the 52 ”perforations of the perforation pattern.

To homogenize an elongated light source, for example a powerful, relatively short but elongated light source such as for example a halogen lamp or a distribution of light sources arranged in rows, a pattern of perforations 30 "'can be used provided with perforations 52'" according to figure 6. The diameter of the perforations 52 '”also increases towards the outside and this pattern of the perforations 30'” is not rotationally symmetrical. In an interior, substantially rectangular, area of the 30 ’” perforation pattern, we have the 52 ’” perforations of smaller diameter to attenuate the high light intensity of the light sources that are directly above this area.

NOMENCLATURE

10 15 Air-conditioned cabinet Support surface 5 20 Housing 22 Plate 24 Plate 26 Light source 28 Pattern of perforations 10 29 Perforation 30 Pattern of perforations 30' Pattern of perforations 30" Pattern of perforations 15 30'" Pattern of perforations 40 First partial area 42 Perforation 50 Second partial area 52 Perforation 20 52 ” Perforation 52 ’” Perforation 60 Third partial area 62 Perforation 25 L1 No grid L2 No grid X X axis Y Y axis

Claims (20)

1) Lighting device for air-conditioned cabinets or development cabinets comprising at least one light source (26) installed between a plate (24) made of a material transparent to light and a plate (22) with the side facing the light source (26) is at least partially reflective, characterized by - a pattern of the perforations (28, 30, 30 ’, 30”, 30 ’”) in non-transparent material on the plate (24) in transparent material, and - the side of the perforation pattern (28, 30, 30 ’, 30”, 30 ’”) facing the light source (26) is reflective. 2) A lighting device according to claim 1, characterized in that the pattern of the perforations (28, 30, 30 ’, 30”, 30 ’”) is printed on the plate (24) made of transparent material, in particular by screen printing. 3 °) Lighting device according to claim 1 or 2, characterized in that the pattern of the perforations (28, 30, 30 ', 30 ”, 30'”) is applied to the side of the plate (24) facing the light source (26), this pattern being made of a transparent material. 4 °) Lighting device according to claim 1, characterized in that the pattern of the perforations (28, 30, 30 ', 30 ”, 30'”) corresponds to the distribution of the light intensity of the light source (26 ). 5 °) Lighting device according to claim 4, characterized in that the pattern of the perforations (28, 30, 30 ', 30 ”, 30'”) corresponds to the distribution of the light intensity of the light source (26 ) in such a way that at the point of the strongest light intensity, the ratio between the closed surface and the surface of the perforations of the perforation pattern (28, 30, 30 ', 30 ”, 30'”) is high and qu 'in places of low light intensity, the ratio between the closed surface and the surface of the perforations of the perforation pattern (28, 30, 30', 30 ”, 30 '”) is low. 6 °) Lighting device according to claims 4 or 5, characterized in that the ratio between the closed surface and the surface of the perforations of the pattern of the perforations (28, 30, 30 ', 30 ”, 30'”) corresponds to report that the light intensity should be reduced in this area. 7 °) lighting device according to claim 1, characterized in that the pattern of the perforations (28, 30, 30 ', 30' ”) corresponds to at least one partial area (40, 50, 60) in which the perforations (42, 52, 62) are distributed according to a network structure. 8 °) lighting device according to claim 1, characterized in that the pattern of the perforations (30) comprises at least a first partial area (40) in which the perforations (42) are distributed in a network pitch (Ll) which is substantially double the diameter of the perforations (42) in the direction of the grating pitch (L1). 9 °) lighting device according to claim 8, characterized in that in the first partial area (40), the perforations (42) are distributed both along the axis X (X) and along the axis Y ( Y), according to the network pitch (Ll) which is substantially double the diameter of the perforations (42) in the direction of the network pitch (Ll). 10 °) Lighting device according to claim 1, characterized in that the pattern of the perforations (30) comprises at least a second partial zone (50) in which the perforations (52) are distributed according to a network period (L2) which is of the order of 1.2 to 1.5 times and no3054643 so much of the order of 4/3 times the diameter of the perforations (52) in the direction of the grating pitch (L2). 11 °) lighting device according to claim 10, characterized in that in the second partial area (50), the perforations (52) are distributed both in the direction of the axis X (X) and in the direction Y (Y) with a network pitch (L2) which corresponds substantially to 1.2 to 1.5 times and in particular to approximately 4/3 times the diameter of the perforations in the direction of the network pitch (L2). 12 °) Lighting device according to claim 1, characterized in that the pattern of the perforations (30) comprises at least a third partial area (60) in which the perforations (62) are distributed in the direction of the axis X (X) according to a lattice period (L2) which corresponds substantially to 1.2-1.5 times and in particular to approximately 4/3 times the diameter of the perforations (62) in the direction of the lattice pitch (L2) and in which the perforations (62) are installed in the direction of the Y axis (Y) with a grating period (L1) substantially double the diameter of the perforations (62) in the direction of the grating pitch (L1). 13 °) Lighting device according to claims 9, 11 and 12, characterized in that the pattern of the perforations (30) has a first partial area (40) substantially square, two third partial areas (60) substantially triangular, adjacent to two opposite end faces of the first partial zone (40), two second partial zones (50) substantially of trapezoidal shape, adjacent to the other opposite sides of the first partial zone (40), as well as four second partial zones (50) substantially triangular, adjacent to the branches of the third partial zones (60) triangular, not facing the first partial zone (40). 14 °) lighting device according to claim 1, characterized in that the plate (24) of a material transparent to light is glass. 15 °) Lighting device according to claim 1, characterized in that the plate (24) made of material transparent to light and the plate (22) whose side facing the light source (26) is at least partially reflective, form part of a housing (20) in which the light source (26) is housed. 16 °) Lighting device according to claim 1, characterized in that the housing (20) has an inner wall formed as a reflective surface, produced independently of the light transparent material of the plate (24). 17 °) Air-conditioned cabinet or development cabinet comprising a lighting device according to one of the preceding claims. 18 °) Method for determining a pattern of the perforations to homogenize the distribution of the light intensity of a certain light source according to a determined adjustment surface, comprising the following steps: - determination of the distribution of the light intensity of the light source device on the support surface, - determination of an average light intensity, - determination of the zones of the distribution of the light intensity and determination of the attenuation of the light intensity in each of the zones to have an average light intensity, - determination of the fraction of the corresponding area of the surface of a transparent plate installed between the light source device and the support surface, which must be covered with a material opaque to light to obtain the desired attenuation, - Determination of the pattern of the perforations so as to install it in the area of the surface of the material not transparent to light and clearance of the perforations to obtain the determined ratio of the closed surface and the surface of the perforations. 19 °) Method according to claim 18, characterized in that the pattern of the perforations is produced so that at the places where the light intensity is strongest, the ratio between the surface 10 closed and the surface of the pattern perforations is higher and that in places of low light intensity, the ratio between the closed surface and the surface of the pattern perforations is low. 20 °) Method according to claim 18 or 19, 15 characterized in that the perforations are distributed regularly in the corresponding zone for example in network structures or according to symmetrical arrangements. 1/5