ES2706397B2 - Illumination spectral control hybrid holographic optical element - Google Patents

Description

DESCRIPTION

Illumination spectral control hybrid holographic optical element

Technical field of the invention

The present invention corresponds to the technical field of holographic optical elements for spectral lighting control, specifically those that refer to passive devices for controlling the level of illumination both in structures and in interiors.

Background of the Invention

At present, there are important energy demands in society, with an increasing trend. To the basic energy demand of a conventional building, formed by the energy needed to supply heating, cooling, domestic hot water production and lighting services, must be added the growing demand due to the need for internet connection both from people and from the digital interconnection of everyday objects with the internet, known as the “internet of things”.

Likewise, in the automotive field, the trend to change from internal combustion engines to electric motors, once again poses higher energy demands in the short term.

Therefore, the need to increase energy production and / or find ways not to waste the existing energy is evident. Solar energy is a renewable and clean source of energy that has already been tried to take advantage of through the use of photovoltaic panels and solar thermal collectors that collect said energy.

But, in addition to the installation of panels on which sunlight falls, to obtain energy, there are places and circumstances in which, being such sunlight annoying, it is treated to avoid it and / or redirect it, preventing its incidence in the same ones, but it is not proposed to give a use to said part of light that is redirected towards another place, therefore there is a clear waste of it.

Thus, a possible example of this waste is in glazed buildings or with large windows in which the incidence of solar radiation is uncomfortable for people inside and also generates an increase in temperatures in these rooms and the building in general. Currently, it is solved by placing blinds or by installing tinted windows in the windows, with which the passage of light is prevented and therefore radiation inside the building is reduced.

In this way, there is a part of the incident light on said structure, which is discarded by preventing its access to it. Said part of the incident light is diverted and wasted, since there is no way to control the spectrum of light at present, in order to redirect the part of interest and take advantage of it in power generation, this energy being clean and renewable.

On the other hand, analyzing the foundation of a holographic optical element, it consists of the storage of a variable interferential structure in a photosensitive medium. By means of holography it is possible to store multiple waves through the procedure known as multiplexing and, applying this to holographic optical elements, allows the expansion of their range of functionality.

A long-term goal has been the replacement of conventional optics by holographic optics, both in reflection systems and in transmission systems, however chromatic dispersion is one of its biggest problems.

As in conventional optics, combinations of holographic optical elements can be generated to achieve optical functionality that allows improving conventional optical systems, resulting in systems of less weight or greater size.

Multiplexing can achieve the storage of more than one object wave, the storage of more than one wavelength or even the combination of storage of holographic optical elements by reflection and / or transmission.

It would be interesting to develop a certain holographic optical element such that, in a passive way, that is, without the need for an electrical supply, it would be able to correctly control the level of illumination that reaches it, according to interests user details, for use in structures or interior rooms.

If this objective is achieved, it would be possible to control the light intensity that affects certain structures, or inside them, in a totally passive way, that is, without the need to activate these elements with any energy means, but by their very nature, they are designed to regulate the amount of light that passes through them.

No holographic optical element has been found in the state of the art that achieves this end.

As an example of the state of the art, reference documents WO2008049914, US2012200831, US5071210, US2014117260, ES2217330, ES2086303, WO02061500, US2012281270, ES2191437 and ES2563645 can be mentioned.

Reference document WO2008049914 defines a holographic display device comprising a first OLED array that writes to a first OASLM (spatially directed optical light modulator), the first OLED array and the first OASLM form adjacent layers and also with a second OLED array and a second OASLM. The device generates a holographic reconstruction when an array of red beams illuminate the first and second OASLM. The first and second OASLM are controlled by the first and second OLED arrays. This device allows independent control of phase and amplitude.

In this case, this document refers to a holographic display. The objective of this device is the generation of 3D images for displays such as mobiles, television screens, etc., as well as the visualization of computer-generated holograms, but in no way is it about generating lighting control.

This device has a multilayer configuration, that is, it consists of many sublayers and each of them deals with an element, so that the layers consist of various light emitting elements (OLED) and spatial light modulators (OASLM). The first pair of layers (OLED and OASLM) allows modulating the amplitude of the array of light beams generated by the LED and the second pair of layers (OLED and OASLM) modulates the phases of the light array. These settings allow 3D viewing of the information that is sent by the LED light. Therefore, it is a system that presents active light devices (light generators) and where the posterior sublayers only modify certain characteristics of said light to provide 3D images, but it does not present phase or amplitude holograms, or polarizing elements. not being a passive lighting control device.

Reference document US2012200831 defines an optical element with a laminated polarization separation layer on the surface of the light guide that transmits x-axis polarized light and reflects y-axis polarized light. The polarization hologram layer is laminated to the separation layer, which diffracts the polarized light on the x-axis, with a prescribed incident angle range to another prescribed diffraction angle and converts the x-axis polarized light to the polarized light on the Axis y.

In this case, the optical element is focused again on displays or screens, both for computers, mobile devices and TVs. They try to improve the light output of current LED screens. This invention tries to generate light in the system to illuminate the screen, for which they have carrier generation layers, plasmon excitation layers, etc. trying to generate light with them.

That is why it refers to optical elements (because they treat light), light emitting sources and projection displays that use the plasmon layer to emit light, but they are active elements that require electricity generation, and not optical elements. passive lighting control in spaces.

Reference document US5071210 discloses a transmission holographic element composed of a first and a second reflective holographic optical element adhesively paired such that the distance separating the two elements is not greater than a few wavelengths of the incident light beam. These two elements work as a single holographic transmission element.

This document tries to generate a transmission hologram by overlapping two reflection holograms. Transmission holograms, as their name suggests, transmit the entire spectrum of visible light, deflecting each wavelength (color) in a different direction. Reflection holograms reflect part of the spectrum of visible light, letting the rest pass through and thus acting as a filter.

In this document, two reflection holograms are used to allow the passage of a part of the spectrum (like a reflection hologram but functioning as transmission), that is, the objective is to make a simple transmission hologram with the spectral filtering provided by the of reflexion. To do this, they overlap and seal in an inverted way, two reflection holograms with different configurations to take advantage of the diffractive properties of the holograms and thus work together as if it were a transmission hologram but improving its optical characteristics.

In this document, therefore, it is not a matter of controlling the light intensity but only of selecting a band of the spectrum to be transmitted.

Reference document US2014117260 defines a grayscale holographic structure having a millimeter wave transmissive material that is provided together with a surface designed to provide different degrees of phase delay as the wave front passes through the material. The possible use of holographic optical elements and different layers with different phase delay per layer is mentioned.

In this case, it is about generating a collimator for radio frequency. A collimated beam is a beam of radiation in which the wavefront of the beam is flat.

Any light emitter generates light but the wave front is not flat. For certain applications, this wavefront needs to be flat, since it is easier to control a flat surface than a sphere or something non-uniform. This document, by means of a complex configuration, with a hologram in the gray scale and a radio frequency system, produce this collimation for radio frequency. These holograms are computer generated and are intended to make a spherical radio frequency wave, after passing through your system, come out as a plane wave, but the control of illumination levels by holograms is not sought.

Reference document ES2217330 defines a device with two holograms, each of which has the same diffraction grating, whereby both holograms induce the same wavelength-dependent diffraction angle and also each hologram has the same index of medium refraction. The second hologram is positioned parallel to the first and with an intermediate optical material of a chosen refractive index. By setting a particular index of refraction for the intermediate optical material, a wavelength-dependent variation in the angle of refraction induced by the intermediate optical material can be made equal to and opposite to the wavelength-dependent variation in the angle of diffraction induced by the first hologram, such that the angles cancel each other out for each wavelength of an incident optical beam having an entrance angle determined for the first hologram of the optical device.

The objective in this case is to create an optical device not for controlling luminosity, but for transmitting light beams, which produces an output beam without marginal scattering, in such a way that destructive interference is produced for all phases and lengths of incident wave over a bandwidth of at least 1% plus or less of the central wavelength of a coherent light source such as a laser. Therefore, the same objective is not sought, nor is it a passive holographic optical element, but rather an active element.

Reference document ES2086303 determines a hologram lens with a focal length dependent on the wavelength of the incident light, arranged to be located at an angle of the optical beam of the tunable laser. The lens converges light to a degree that depends on the wavelength. The focal point on an image plane is scanned in the directions shown by arrows.

In this case, the document deals with a holographic light diverter. Thus, it is intended to change the direction of propagation of a laser light by means of holograms so as not to use conventional optics that require movement.

To do this, they take advantage of the properties of transmission holograms that transmit the entire spectrum of visible light, deflecting each wavelength (color) in a different direction. Thus, they try to make a system in which depending on the input wavelength provided by a tunable laser, the output is produced in one direction or another.

Therefore, the diffractive properties of transmission holograms are used here, changing the direction of light exit. This can only be done with monochromatic light (single wavelength, single color), therefore it only works with laser light. They use a tunable laser, which can emit many colors (but one at a time). It does not try to control the intensity of light, nor does it work with white light, nor does it present multilayers of various holograms or polarizers.

Reference document WO02061500 presents a method for spectral filtering of optical radiation. A holographic lattice is etched into the various layers so that each layer of the photosensitive material contains a portion thereof. The optical output signal is formed as a result of interference from reflected light due to diffraction of Bragg. The reflected light propagates through the electro-optic layers between the photosensitive layers.

In this case, it is a question of making a spectral filter of optical radiation, more specifically of making a narrow-band tunable optical filter. These filters are quite common and are geared toward filtering for optical communications.

The objective is the filtering of the light that carries information through the waveguides. It is a tunable method and they use photorefractive and electro-optical materials, so they are active materials that vary their optical properties according to the electrical charge they receive. In this case, multilayers of phase or amplitude holograms are not used either, they do not handle white light, but mainly the LED or laser light typical of optical communications and they do not try to control light intensity.

This invention is framed in the field of optical communications and information transfer.

Reference document US2012281270 presents a phase change optical element that includes a stack of colored filters, a hologram, a diffraction grating, or layers with materials with specific thickness and wavelength-dependent refractive indices.

In this case, it is a matter of generating tunable color light projector systems (RGB), illuminated by broadband light. They are framed in the sector of displays for screens on mobile devices, TV, computers, etc. They use electromechanical systems to generate white light by emitting RGB light (red, green and blue) typical of the pixels of the screens.

In addition, they use electromechanical devices and therefore not passive. They do not try to control the intensity of light, but rather try to generate a pixel of light to be used on the screens. They use a source of white light on the device and try to manipulate it to obtain the RGB that provide the colors that the pixel requires at all times.

Reference document ES2191437 discloses an optical multilayer system prepared using modified inorganic solutions and a heat treatment process.

In this case, a method of generating a multilayer optical system is presented, like many others existing in the state of the art, to be used in interference filters and anti-reflective filters. These filters are common in communications optics. In this case they try to carry out a construction method by depositing a sol-gel solution, polymerization, etc., not using polarizers, or holograms, etc.

They do not try to control the intensity of light, but rather the realization of anti-reflective filters and interference filters for optical communications.

Reference document ES2563645 discloses a modular system with a holographic optical element, connected in a fixed structure to an optical concentrator with a very similar refractive index. The optical concentrator is designed to concentrate radiation from the holographic optical element. A radiation receiver, for example a photovoltaic solar cell, is located at the focal length of the optical concentrator, which is again an active and not a passive system.

From US2016 / 0027943 a window is known, comprising a substantially flat glass substrate having a mass defined by first and second main surfaces and edges substantially orthogonal to the first and second main surfaces; a photovoltaic module placed, directly or indirectly, on one of said edges of the substrate, and a plurality of holographic optical elements located on at least the second main surface of the substrate, registering and positioning the holographic optical elements in such a way as to alter the amplitude and / or phase of the light incident on them to holographically project light of a selected range of wavelengths onto the photovoltaic module.

Therefore, the conclusion obtained is that a passive device formed by a holographic optical element whose objective is the control of luminosity in structures and rooms is not known in the state of the art.

Description of the invention

The hybrid holographic optical element (HOE) for spectral lighting control, said holographic optical element being a passive device for controlling the level of illumination both in structures and interiors that is presented here, is formed by a laminar body with a series of superimposed layers, comprising a first outer layer formed by transparent support means, a second outer layer opposite the previous one, formed by protective means and, intermediate said first and second outer layers it comprises a layer formed by a reflection phase hologram arranged adjacent to the first outer layer and at least one layer formed by means of light suppression or dimming.

According to a preferred embodiment, the light suppression or dimming means comprise a layer formed by a holographic amplitude filter.

According to another preferred embodiment, the light suppression or dimming means comprise two adjacent layers each formed by a polarizer.

According to another aspect, in a preferred embodiment, the HOE comprises an additional layer formed by a transmission phase hologram, arranged between the layer of the reflection phase hologram and the at least one layer of the light suppression or dimming means , adjacent to both.

According to a preferred embodiment, the HOE comprises a layer formed by a diffuser arranged adjacent to the light suppression or dimming means.

According to a preferred embodiment, the diffuser is formed by a holographic diffuser.

According to another preferred embodiment, the diffuser has characteristics suitable for protecting the holographic optical element, such that the protection means that make up the second outer layer are formed by said diffuser.

In this case and in a preferred embodiment, the diffuser is made of a ground glass.

According to another aspect, in a preferred embodiment, the protection means are formed by a transparent layer formed by methacrylate, acetate, glass, tempered glass or transparent material with similar resistance characteristics.

According to a preferred embodiment, the transparent support means that make up the first outer layer are formed by a layer of methacrylate, acetate, glass, tempered glass or transparent material with similar resistance characteristics.

In another preferred embodiment, the reflection phase hologram comprises a support layer thereof and the transparent support means that make up the first outer layer are formed by said support layer.

According to another aspect, at least one of the layers of the holographic optical element has a different size than the rest.

With the illumination spectral control hybrid holographic optical element proposed here, a significant improvement of the state of the art is obtained.

This is so because a holographic optical element consisting of a passive device is achieved, with which it is possible to control the lighting level for structures or interiors, while allowing spectral control of the light, both outside the structure and inward.

With this HOE it is possible to carry out jointly and simultaneously, a series of optical functionalities, consisting of a control of spectral reflectance, a control of spectral and spatial focusing, a control of spectral transmittance, a control of spatial reflectance and angularly spectral and angularly and spatially focused control.

In this way and thanks to its multilayer constitution, where each one has a function, one effect or another can be obtained depending on the combination of layers from which it is formed.

Thus, with this HOE it is always possible to control the spectral reflectance by means of the layer formed by the reflection phase hologram and the amount of light intensity that enters the structure, by means of light suppression or obscuration.

Apart from this, it is possible to redirect part of the spectrum not blocked by the phase hologram by reflection, towards the interior of the structure, by means of a phase hologram by transmission and, if a diffuser is also provided, a uniform illumination is achieved.

Therefore, a holographic optical element is achieved that achieves both the control of the luminosity that affects a structure, and the type of radiation that manages to access it. Furthermore, with the spectral control of radiation, it is possible to reuse the deflected radiation, reorienting it to take advantage of it in power generation, for example. And this, both with the radiation diverted to the outside and with the radiation that is allowed to enter the interior.

In this way, a simple and practical HOE is achieved, which achieves great energy efficiency by taking advantage of the incident radiation on the structures.

Brief description of the drawings

In order to help a better understanding of the characteristics of the invention, according to a preferred example of a practical embodiment thereof, a series of drawings is provided as an integral part of said description where, with an illustrative and non-limiting nature, it has been provided represented the following:

Figure 1.- Shows a schematic view of the section of the holographic optical element for a first preferred embodiment of the invention.

Figure 2.- Shows an exploded view of the layers of the holographic optical element for a first preferred embodiment of the invention.

Figure 3.- Shows a schematic view of the section of the holographic optical element for a second preferred embodiment of the invention.

Detailed description of a preferred embodiment of the invention

In view of the figures provided, it can be seen how in a first preferred embodiment of the invention, the hybrid holographic optical element (1) for spectral control of illumination proposed here is a passive device for controlling the level of lighting both in structures and interiors.

This holographic optical element (1) is formed by a laminar body with a series of superimposed layers, which comprises a first outer layer formed by means of transparent support (2), a second outer layer opposite the previous one, formed by protection means (3) and, intermediate said first and second outer layers, comprises a layer formed by a reflection phase hologram (4) arranged adjacent to the transparent support means (2) that form the first outer layer and, at least one layer formed by means of light suppression or darkening.

Said transparent support means (2) have a protection function and in this first preferred embodiment of the invention they are formed of methacrylate, this first outer layer being larger than the rest of the layers of the holographic optical element, as can seen in Figure 2.

The protection means (3) that form the second outer layer also have a function of protection against blows, humidity ... and provide stability, sealing and robustness to the holographic optical element (1).

For its part, the layer formed by the reflection phase hologram (4) controls the reflected wavelength variables, the bandwidth of the reflected spectrum, the focusing factor and the direction of reflection. This layer has the purpose of reflecting part of the spectrum towards the outside, thus performing a spectral filtering, while concentrating the light and directing it where it is necessary and, this characteristic is used in this first preferred embodiment of the invention, to use that part of the filtered spectrum to reuse it generating energy.

Regarding the means of suppressing luminosity or darkening, these consist of one or more layers that control the amount of light intensity that accesses the interior, in a certain percentage depending on the nature of said layers used, and that it is between 0 and 100%, once the reflection losses in the layers preceding said media have been considered.

As shown in Figures 1 and 2, in this first preferred embodiment of the invention, the light suppression or darkening means comprise a layer formed by a holographic amplitude filter (5.1).

In this first embodiment, the holographic amplitude filter (5.1) is a transmission hologram and controls the amount of light that enters the structure. To do this, the hologram of amplitude can have variable density, being able to let pass from 100% of light to 30% of the light that falls on the layer, once the losses due to reflection in the layers that precede this filter have been considered.

Furthermore, in this preferred embodiment of the invention, the holographic optical element (1) comprises an additional layer formed by a transmission phase hologram (6), arranged between the layer of the reflection phase hologram (4) and said holographic amplitude filter (5.1) that forms the means of light suppression or darkening, adjacent to both.

With this layer of the phase hologram by transmission (6), it is possible to redirect the part of the spectrum not blocked by the layer of the phase hologram by reflection (4) towards the interior.

As this layer is capable of concentrating the light and directing it where it is necessary, it is used to redirect that part of the radiation and use it for a certain purpose, such as the generation of energy.

Thus, since there are both reflection and transmission phase holograms (4, 6), located prior to the light suppression or darkening means, the percentage of luminosity that is prevented from entering by said light suppression means u darkening, is between 100 and 30% of the light that reaches them, that is, the percentage that is allowed to pass through the phase hologram by reflection (4) and the phase hologram by transmission (6) .

As shown in Figures 1 and 2, in this first preferred embodiment of the invention, the holographic optical element (1) further comprises a layer formed by a diffuser (7) arranged adjacent to the light suppression means or darkening.

In this preferred embodiment of the invention, the diffuser (7) has characteristics suitable for the protection of the holographic optical element (1), as it is formed by a ground glass, so that the protection means (3) that make up the The second outer layer is formed by said diffuser (7) and in this way, as can be seen in Figures 1 and 2, the diffuser layer (7) coincides with the second outer layer.

In this specification a second preferred embodiment of the invention is proposed in which the holographic optical element (1), as shown in Figure 3, again presents a first outer layer formed by transparent support means (2) , a second outer layer formed by protection means (3), as well as a layer formed by a reflection phase hologram (4) and at least one layer formed by means of light suppression or darkening.

In this second preferred embodiment of the invention, the reflection phase hologram (4) comprises a support layer thereof, so that the transparent support means (2) that make up the first outer layer are formed by said layer of support.

In this second preferred embodiment of the invention, as can be seen in Figure 3, the holographic optical element (1) comprises, as in the first proposed mode, an additional layer formed by a transmission phase hologram (6) , arranged adjacent to the layer of the reflection phase hologram (4), placed between it and the light suppression or dimming means.

As shown in Figure 3, in this second preferred embodiment of the invention, the light suppression or dimming means comprise two adjacent layers each formed by a polarizer (5.2). Both polarizers (5.2) control the amount of light intensity that enters the interior and, depending on the relative angle between them, they can allow between 30 and 0% of the light that falls on them, once the losses due to reflection have been considered.

In this second preferred embodiment of the invention, the holographic optical element (1) also comprises a layer formed by a diffuser (7) arranged adjacent to the light suppression or dimming means. In this case, it is made up of a holographic diffuser.

The second outer layer formed by the protection means (3), is formed in this second embodiment by a transparent layer of methacrylate.

In this second preferred embodiment of the invention, all the layers of the holographic optical element (1) have the same size.

The described embodiments constitute only examples of the present invention, therefore, the specific details, terms and phrases used in the present specification are not to be considered as limiting, but are to be understood only as a basis for the claims and as a representative basis that provides an understandable description as well as sufficient information to the person skilled in the art to apply the present invention.

With the illumination spectral control hybrid holographic optical element presented here, important improvements are achieved with respect to the state of the art.

The result is a holographic optical element that, passively, is capable of carrying out a spectral control of lighting in structures and interiors, so that it only lets through that part of radiation that is of interest in each specific case and also can redirect both the part of said radiation rejected to the outside, as the part that is allowed to enter the interior, to use it in the generation of energy.

This is achieved with the two layers formed by phase reflection and transmission holograms.

The phase reflection hologram is capable of controlling the reflectance spectrum of the layer, being able to fully or partially reflect all or part of the visible, ultraviolet or infrared spectrum, depending on the need or required application and it can also have focusing properties that allow a uniform reflection of the range of the desired spectrum, producing a divergent reflection or to focus this reflection on a desired position and distance, so that it can be used, for example in power generation.

On the other hand, the transmission phase hologram controls the transmittance spectrum of the layer, being able to fully or partially reflect all or part of the visible, ultraviolet or infrared spectrum, again according to the specific need. This layer complements the previous one, blocking or letting pass part of the radiation allowed by that layer and, like said layer, is capable of modifying the direction of propagation of the radiation that is allowed access to the interior, focusing it or causing it to diverge.

Therefore, in addition to controlling the level of luminosity in structures and interiors, this holographic optical element is able to take advantage of the spectrum of light that interests it in different uses, such as lighting or generating energy, so it is very effective.

This holographic optical element is also a passive device, so it does not need a power supply, it has very low maintenance costs and allows for sustainable energy production, which is why it is highly recommended.

Claims (1)

1- Holographic optical element (1) hybrid lighting spectral control, said holographic optical element (1) being a passive device for controlling the level of illumination both in structures and interiors, which presents a laminar body formed by a series of overlapping layers, comprising: - a first outer layer formed by transparent support means (2), - a second outer layer opposite the previous one, formed by protection means (3), and - an intermediate layer to said first and second outer layers formed by a reflection phase hologram (4), said intermediate layer being arranged adjacent to the first outer layer, characterized in that said layer formed by a phase reflection hologram (4) controls the spectral reflectance and the part of the spectrum that is allowed to pass and because intermediate said first and second outer layers, the holographic optical element also comprises: - at least one layer formed by means of light suppression or darkening that controls the amount of light intensity that enters the interior, wherein said light suppression element is selected from: a layer formed by a holographic filter of amplitude (5.1), two adjacent layers each formed by a polarizer (5.2), or a combination thereof, said light suppression or dimming element being disposed between said intermediate layer and said second outer layer; and - An additional layer formed by a transmission phase hologram (6) arranged between the reflection phase hologram layer (4) and the at least one layer of the light suppression or dimming means, adjacent to both, controlling said additional layer the transmittance spectrum and being applied to redirect part of the spectrum not blocked by the phase hologram by reflection, towards the interior of the structure. 2- Holographic optical element (1) for illumination spectral control, according to claim 1, characterized in that it also comprises a layer formed by a diffuser (7) arranged adjacent to the light suppression or dimming means. 3- Holographic optical element (1) hybrid illumination spectral control, according to claim 2, characterized in that the diffuser (7) is formed by a holographic diffuser. 4- Holographic optical element (1), hybrid lighting spectral control, according to claim 3, characterized in that the diffuser (7) has characteristics suitable for protecting the holographic optical element (1), the protection means (3) being formed ) that make up the second outer layer, by said diffuser (7). 5- Holographic optical element (1) hybrid illumination spectral control, according to claim 4, characterized in that the diffuser (7) is formed by a ground glass. 6- Holographic optical element (1) hybrid illumination spectral control, according to any of claims 1 to 5, characterized in that the protection means (3) that make up the second outer layer are formed by a transparent layer formed by methacrylate, acetate, glass, tempered glass or transparent material with similar resistance characteristics. 7- Holographic optical element (1) hybrid lighting spectral control, according to any of the preceding claims, characterized in that the transparent support means (2) that make up the first outer layer are formed by a layer of methacrylate, acetate, glass , tempered glass or transparent material with similar resistance characteristics. 8- Holographic optical element (1) hybrid lighting spectral control, according to any of claims 1 to 7, characterized in that the reflection phase hologram (4) comprises a support layer thereof and transparent support means ( 2) that make up the first outer layer constitute said support layer. 9- Holographic optical element (1) hybrid illumination spectral control, according to any of the preceding claims, characterized in that at least one of the component layers has a different size than the rest.