JP6854020B2 - Method for manufacturing a holographic lighting device and method for manufacturing a holographic optical element - Google Patents

Description

The present invention relates to a holographic lighting device, a hologram display device, and a holographic optical element manufacturing device and manufacturing method used for these.

In recent years, holograms that project a three-dimensional image in space have been used in many situations. For example, displaying a company logo, a product description, a sales promotion advertisement, or a work of art in three dimensions by a hologram is effective in attracting the interest of an observer.

Generally, a hologram is formed by irradiating a photosensitive material with object light and reference light. When the object light and the reference light interfere with each other, a photoreaction occurs in the hologram recording layer of the photosensitive material, and the hologram is fixed as interference fringes. Then, when the hologram is irradiated with light corresponding to the reference light at the time of recording (reproduction illumination light), diffraction occurs and light corresponding to the object light at the time of recording (regeneration light) is generated. This allows the observer to observe the stereoscopic image recorded on the hologram. Since laser light having coherence is generally used as the reference light at the time of recording, the reproduction illumination light used at the time of reproduction is also required to have the same wavelength and the same incident angle as the reference light at the time of recording. With various irradiation conditions.

Therefore, a special lighting device using an LED light source has been proposed as a means for irradiating the regenerated illumination light for reproducing the hologram (see, for example, Patent Document 1). Patent Document 1 discloses a rectangular lighting device including a collimator that converts light from an LED light source into substantially parallel light. Further, as an embodiment of such a lighting device, a hologram lighting device including a frame body for holding a plurality of lighting devices, a holding portion for holding a hologram, and the like is disclosed.

Further, a device suitable for an exhibition that can be stored compactly has been proposed (see, for example, Patent Document 2). Patent Document 2 includes a lighting fixture (LED and Fresnel lens), an arm that supports the lighting fixture and can adjust the angle and position with respect to the held hologram, and a hologram display device that irradiates the hologram with illumination light. Is disclosed.

JP-A-2009-245803 JP-A-2009-69527

The lighting device described in Patent Document 1 can irradiate a substantially parallel light on a rectangular irradiation area. It has also been proposed to connect a plurality of irradiation devices to form an illumination system capable of irradiating a wide range. However, when it is intended to irradiate a hologram on which a stereoscopic image is recorded with substantially parallel light, it is necessary to precisely adjust the angle and position of the lighting device. In addition, depending on the surrounding environment, the installation location of the lighting device may be restricted.

Further, Patent Document 1 also discloses a hologram lighting device that defines a positional relationship between a light source and a hologram, but such a device is not suitable for carrying because of its large size and large volume, and for installation. Requires a certain amount of space. In addition, there is a problem that such a lighting device is expensive.

On the other hand, the hologram display device described in Patent Document 2 is configured to be foldable and is convenient to carry. However, since the structure of irradiating substantially parallel light from the LED and the Fresnel lens is adopted, the irradiation area of substantially parallel light is limited. Therefore, the size of the applicable hologram sheet is limited, and it is difficult to display a relatively large stereoscopic image. Further, since the arm holding the LED projects over the observation area of the hologram, there is a problem that the arm itself becomes a protrusion and spoils the aesthetic appearance of the exhibition booth, etc., in addition to hindering the observation of the stereoscopic image. ..

In addition, in the devices described in Patent Documents 1 and 2, the high-power illumination light of the lighting device may be reflected by the hologram surface or each part of the device, and depending on the observation position, the high-power light is reflected. The observer may hurt his eyes. In addition, the frame or body that is constantly irradiated with high-power irradiation light may be deteriorated by heat.

As mentioned above, a special lighting device is required to reproduce the hologram. However, conventional lighting devices have various problems, and so far there has been no thin, lightweight, and simple lighting device suitable for hologram reproduction. And this is one of the factors that hinder the use and spread of holograms.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a hologram lighting device and a hologram display device capable of solving at least a part of such problems. Another object of the present invention is to provide a manufacturing device and a manufacturing method of a holographic element for lighting used in such a device.

In order to solve the above-mentioned problems, the hologram lighting device of the present invention receives at least a part of a light source, a light guide plate propagating light from the light source, and light propagating through the light guide plate to form a stereoscopic image. An illumination holographic optical element that irradiates a recorded image reproduction hologram with reproduction illumination light at a predetermined angle, and a holding means for holding the light guide plate, the illumination holographic optical element, and the image reproduction hologram. It is characterized by having.

In the hologram lighting device, it is preferable that the holographic optical element for illumination can reproduce the regenerated illumination light by light having an incident angle larger than the critical angle of the light guide plate. It is preferable that the holographic optical element for illumination can reproduce the regenerated illumination light by light incident from different directions of the light guide plate. It is preferable that the holographic optical element for illumination can reproduce different reproduction illumination light by light incident from different directions of the light guide plate.

Further, the holographic optical element for illumination may be provided on the rear surface of the light guide plate and may irradiate the rear side of the light guide plate with the regenerated illumination light at a predetermined angle. The holographic optical element for illumination may be provided on the front surface of the light guide plate and may irradiate the rear side of the light guide plate with the regenerated illumination light at a predetermined angle. The holographic optical element for illumination may be provided on the front surface of the light guide plate and may irradiate the front side of the light guide plate with the regenerated illumination light at a predetermined angle.

Further, it is preferable that the end portion of the light guide plate is provided with a parallelizing optical system for converting the light diffused from the light source into substantially parallel light. At least a part of the parallel optical system may be integrally provided on the light guide plate.

The hologram display device of the present invention is characterized in that an image reproduction hologram that reproduces a stereoscopic image by the reproduction illumination light at a predetermined angle is attached to the hologram illumination device.

The holographic optical element manufacturing apparatus of the present invention includes a light source, a beam splitter that separates light from the light source into two light beams, a high numerical aperture objective lens, and incident light from the light source to the high numerical aperture objective lens. It is arranged on one of the optical paths of the optical system that forms an image as a point light source on the pupil surface and the two light beams separated by the beam splitter, and the imaging position of the high numerical aperture objective lens on the incident pupil surface is set in the incident pupil surface. A second shift means for displacement and a second shift means, which is arranged on the other optical path of the two light beams separated by the beam splitter and displaces the imaging position of the high numerical aperture objective lens on the incident pupil plane in the incident pupil plane. Shift means, displacement amount changing means for changing the displacement amount of the imaging position by the first shift means, a mounting table for holding the photosensitive material, and reflection provided between the above-described stand and the photosensitive material. It is characterized by being provided with preventive means.

In the holographic optical element manufacturing apparatus, the antireflection means preferably has a moth-eye structure.

In the method for producing the holographic optical element for illumination of the present invention, the photosensitive material of the holographic optical element for illumination is arranged so as to be in contact with the immersion objective lens via the immersion liquid, and the light from the light source is separated into two light beams. Then, reference light and object light are generated so as to pass through a first point on the incident pupil surface of the immersion objective lens, which is separated by a first displacement amount from the central axis of the immersion objective lens. While irradiating the immersion objective lens with the reference light and using the reference light refracted at a first angle corresponding to the first displacement amount as the photosensitive material, the first from the central axis of the immersion objective lens. The object light is irradiated to the immersion objective lens so as to pass through a second point separated by a displacement amount of 2, and the object light is refracted at a second angle corresponding to the second displacement amount. Is irradiated to the photosensitive material.

In the method for manufacturing the holographic optical element for illumination, it is preferable to change the first displacement amount by moving the first prism provided on the optical path of the reference light. An antireflection means having a moth-eye structure may be arranged after the photosensitive material.

According to the present invention, it is possible to provide a hologram lighting device or a hologram display device that is thin and lightweight, is convenient to carry, and can be applied to a hologram recording medium having a relatively large area. Other effects will be described in the embodiment for carrying out the invention.

Schematic configuration of the hologram lighting device of the present invention Another Example of the Holographic Lighting Device of the Present Invention Example of parallelizing optical system for light guide plate Another example of a parallelizing optical system for a light guide plate Example of hologram recording method Examples of the configuration of the light source and the light guide plate of the present invention

The present invention provides optics such as a conventional Fresnel lens or collimator lens configured to irradiate substantially parallel light at a predetermined angle as a means of irradiating reproduction reference light for displaying a stereoscopic image recorded on a hologram. Instead of the element, a holographic optical element (HOE) configured to emit at least a part of the light propagating through the light guide plate at a predetermined angle is adopted.

Hereinafter, such a holographic optical element is referred to as an "illumination holographic optical element (illumination HOE)", and a hologram for generating regenerated illumination light recorded in the illumination HOE is referred to as an "illumination hologram". Further, a hologram for reproducing a stereoscopic image to be displayed is referred to as an "image reproduction hologram", and a medium on which an image reproduction hologram is recorded or formed is referred to as an "image reproduction hologram recording medium".

The hologram lighting device of the present invention has a thin flat plate shape, is lightweight, and is configured to be portable (see FIG. 1 or 2 below). When the dimensions of the hologram lighting device 1 are expressed in height (X direction), width (Y direction) and thickness (Z direction), the plane defined by height x width is used as a reference, and the method of the plane is used as a reference. For the line N, the incident angle, the exit angle, the reflection angle, etc., which will be described later, are defined. Further, the direction in which light travels in the XY plane is called "direction". Further, the side on which the observer 100 is located is referred to as the "front side" and the side opposite to the observer 100 is referred to as the "rear side" with respect to the plane of the hologram lighting device.

The hologram lighting device 1 of the present invention receives at least a part of the light source 2, the light guide plate 4 propagating the light 3 from the light source 2, and the light 3 propagating in the light guide plate 4, and is used for image reproduction. The hologram recording medium 6 is provided with an illumination HOE 5 that irradiates the reproduction illumination light 32 at a predetermined angle, and a holding means 7 that holds them in a predetermined positional relationship. The hologram lighting device 1 is preferably configured so that the image reproduction hologram recording medium 6 can be easily removed and attached. Further, the hologram display device 10 may be used in a state where the image reproduction hologram recording medium 6 is attached to the hologram illumination device 1.

The illumination HOE 5 receives the light from the light source 2 propagating in the light guide plate 4 and irradiates the attached image reproduction hologram recording medium 6 with the reproduction illumination light 32 at a predetermined angle. Is formed. Further, when the illumination HOE 5 is arranged on the front side of the image reproduction hologram recording medium 6, the reproduction light 34 reproduced from the image reproduction hologram recording medium 6 can be passed to the front side. Further, the illumination HOE5 may be multiple-recorded so that a plurality of illumination holograms overlap each other, and even if one type of reproduction illumination light is reproducible by light having different directions, incident angles, and wavelengths. Alternatively, a plurality of regenerated illumination lights may be reproducibly configured with light having different directions, incident angles, and wavelengths.

In the hologram lighting device 1 or the hologram display device 10, the light guide plate 4, the lighting HOE 5, and the image reproduction hologram recording medium 6 can be arranged in an appropriate order according to the mode of use. For example, the lighting HOE 5 can adopt a transmissive type or a reflective type, and when the transmissive type is adopted, the lighting HOE 5 is arranged behind the light guide plate 4 (see FIG. 1), and the reflective type is adopted. In this case, the lighting HOE 5 can be arranged on the front side of the light guide plate 4 (see FIG. 2). Further, the image reproduction hologram recording medium 6 can also adopt a transmission type or a reflection type, and can be appropriately arranged. For example, the image reproduction hologram recording medium 6 may be arranged on the front side or the rear side of the light guide plate 4. It is preferable that the HOE 5 for illumination and the hologram recording medium 6 for image reproduction are arranged in parallel, but the hologram recording medium 6 for image reproduction may be irradiated with the reproduction illumination light 32 at a desired angle. It does not have to be arranged in parallel accordingly.

When the image reproduction hologram recording medium 6 is irradiated with the predetermined reproduction illumination light 32, the reproduction light 34 is generated, and the hologram illumination device 1 or the hologram display device 10 displays the stereoscopic image 60. The apparent position of the stereoscopic image 60 corresponds to the position of the subject at the time of recording the hologram. Therefore, in the present invention, depending on the hologram recording method, the stereoscopic image 60A can be apparently displayed on the front side of the hologram lighting device 1, and the stereoscopic image 60B is displayed on the rear side. It can also be configured to be. In other words, the observer 100 may be configured to directly observe the stereoscopic image 60A on the front side of the image reproduction hologram recording medium 6, or may be configured on the rear side of the image reproduction hologram recording medium 6 (image reproduction hologram). It may be configured so that the stereoscopic image 60B can be observed (through the recording medium 6).

The light source 2 is a light source capable of emitting light having the same wavelength as the reference light used at the time of recording the illumination HOE5, and is an LED, a xenon lamp, a semiconductor laser, an organic EL element, and an ultra-small fluorescent tube for a liquid crystal backlight. Etc. can be adopted. The light source 2 is preferably provided at the end of the light guide plate 4. The light source 2 may be arranged on the same surface as the light guide plate 4 (see FIGS. 1 and 3), or may be arranged on the rear side of the light guide plate 4 (see FIGS. 2 and 4). However, the present invention is not limited to this, and the light source 2 may be arranged in contact with the front surface of the light guide plate 4 when the hologram lighting device 1 is used, depending on the mode of use of the hologram lighting device 1. Alternatively, it may be arranged away from the light guide plate 4. Moreover, you may arrange a plurality of light sources 2. Further, the light source 2 may be arranged at the center of the light guide plate 4 or the like as long as it does not interfere with the observation of the stereoscopic image 60. In the past, in order to illuminate a square hologram recording medium using a circular illuminating device with a bright central part, it was necessary to illuminate the square hologram recording medium from a distance diagonally above, including the extra part around the hologram recording medium. In the hologram lighting device 1 of the present invention, parallel light having a uniform angle is made into the size of the image reproduction hologram recording medium from the vicinity of the image reproduction hologram recording medium 6 by the illumination HOE 5, and the illumination unevenness is small. Since it can be irradiated as the regenerative illumination light 32, a light source 2 having a weak output of 50% or less as compared with the conventional one (for example, hololite (registered trademark) parallel illumination type HL01) can be adopted.

According to the present invention, it is possible to provide a holographic lighting device that is thin and lightweight and is convenient to carry. Further, by adopting the configuration of the illumination HOE and the light guide plate, it is possible to irradiate the hologram recording medium with the reproduction illumination light at a predetermined angle, and it is not necessary to set strict alignment and irradiation conditions. Further, since the sizes of the illumination HOE and the light guide plate can be appropriately set according to the size of the hologram recording medium to be displayed, the reproduction illumination light covers a relatively wide range as compared with the conventional illumination device. Can be uniformly irradiated. Unlike the conventional lighting device, the hologram lighting device of the present invention does not need to support and fix the light source to the outside of the device in order to irradiate light at a predetermined angle, and therefore is not restricted in the installation location. Further, since an arm or the like overhanging the observation area is not required, the visibility of the stereoscopic image is improved and the appearance of the device is not spoiled. Further, the lighting HOE can be easily mass-produced by duplicating the master once the master is produced, so that the hologram lighting device can be provided at low cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.

[Basic configuration]
FIG. 1 is a schematic configuration diagram of the hologram lighting device of the present invention. The hologram lighting device 1 includes a light source 2, a light guide plate 4, a lighting HOE 5, and a holding means 7 for holding these. The hologram lighting device 1 may be configured so that a separately produced hologram recording medium 6 for image reproduction can be attached and detached by a simple operation via the holding means 7. Thereby, for example, the user can carry the hologram lighting device 1 to an exhibition hall or the like, and the plurality of image reproduction hologram recording media 6 can be sequentially replaced in the exhibition hall or the like according to the purpose.

On the other hand, it can also be used as the hologram display device 10 in a state where the image reproduction hologram recording medium 6 is attached to the hologram lighting device 1. In this case, the hologram display device 10 can be used like a picture frame containing a painting work, and a three-dimensional image is constantly displayed.

The light source 2 is a light source capable of emitting light having the same wavelength as the reference light used at the time of recording the illumination HOE 5, and an LED or the like can be adopted. The light source 2 is arranged so that light is incident from the end face of the light guide plate 4. The light source 2 may be arranged so as to be in contact with the end portion of the light guide plate 4, or may be arranged away from the end portion of the light guide plate 4. The light source 2 irradiates the inside of the light guide plate 4 with light (diffused light) 3 having a predetermined wavelength. When the diffused light from the light source 2 is incident on the front surface of the light guide plate 4 at an angle smaller than the critical angle, the incident light may be emitted from the light guide plate 4 and irradiated to the observer. Therefore, it is preferable that the light source 2 is configured to supply light to the light guide plate 4 at an angle larger than the critical angle with respect to the front surface of the light guide plate 4 as much as possible.

The light guide plate 4 is a means for propagating the light 3 from the light source 2, and a translucent material such as glass or resin can be adopted. The front surface of the light guide plate 4 is preferably flat. As a result, the ambient external light is not diffusely reflected on the front surface of the light guide plate 4, so that there is less possibility that the observer 100 will hinder the observation of the stereoscopic image 60. Further, the light propagating inside the light guide plate 4 is not diffusely reflected on the front surface, so that the propagation efficiency can be improved.

On the front surface of the light guide plate 4, among the light from the light source 2, the light incident at a critical angle θc or more is totally reflected toward the rear side. The critical angle θc is an angle defined by the refractive index of the light guide plate 4 and air. On the other hand, a part of the light incident at an angle smaller than the critical angle θc is emitted toward the front side (observer side) with an emission angle defined in relation to the refractive index. Therefore, it is preferable that the light source 2 is arranged or configured so as not to directly irradiate the front surface of the light guide plate 4 with light having an angle smaller than the critical angle θc. As a result, the light from the light source is not emitted to the observer side, so that the light source itself does not interfere with the observation as compared with the case where the light source is provided outside the device, and the observer 100 There is little risk of damaging the eyes. Further, the light from the light source 2 can be efficiently used as the reproduction illumination light 32. Other examples of the arrangement of the light source 2 and the irradiation mode will be described later with reference to FIGS. 3 and 4.

The illumination HOE 5 is a kind of optical element in which an illumination hologram having a deflection function is formed on a photosensitive material, and in this example, it is arranged as a transmissive hologram in contact with the rear surface of the light guide plate 4. When the incident light 30 is incident on the illumination HOE 5 from the rear surface of the light guide plate 4 at an incident angle θ1 in a predetermined range among the light 3 propagating inside the light guide plate 4, the illumination HOE 5 is transmitted from the illumination hologram. The reproduction illumination light 32, which is parallel light having a predetermined emission angle θ2, is reproduced and irradiated toward the image reproduction hologram recording medium 6.

The illumination hologram of the illumination HOE5 records interference fringes formed by interference between object light and reference light, and irradiates light of the same wavelength from the same direction as the reference light at the same incident angle. Then, light of the same wavelength is reproduced and emitted in the same direction as the object light and at the same angle. Therefore, the object light has a predetermined direction (from top to bottom in FIG. 1) from the front side to the rear side of the illumination HOE 5 so as to travel in the same direction as the regeneration irradiation light 32 and at the same angle. Then, the parallel light having an incident angle θ2 is irradiated. Further, as the reference light, light having a wavelength emitted from the light source 2 is emitted from the front side to the rear side of the illumination HOE 5 at an incident angle θ1 corresponding to the incident light 30 incident on the illumination HOE 5 from the light guide plate 4. Irradiate with. The range of the incident angle θ1 can be set as appropriate. For example, the incident angle θ1 is an angle inside the light guide plate 4, and may be set in the range of 0 ° <θ1 <90 °. When most of the light propagating inside the light guide plate 4 repeats total internal reflection at an angle equal to or greater than the critical angle θc, the incident angle θ1 can be set in the range of θc <θ1 <90 °. When the light guide plate is formed with a thin thickness, the incident angle θ1 is preferably 50 ° <θ1 <90 °. Further, in order to widen the incident angle and the incident direction (weaken the angle selectivity), it is realized by reducing the thickness of the recording medium of the illumination HOE5. The thickness of the hologram recording medium of the lighting HOE5 is about 1 to 500 μm, but when the angle selectivity is weakened, the thickness is preferably 2 to 20 μm.

The regenerated illumination light 32 from the illumination HOE5 corresponds to the object light used at the time of recording the illumination HOE5, and the emission angle θ2 of the regenerative illumination light 32 corresponds to the angle of the object light. The emission angle θ2 of the reproduction illumination light 32 needs to be set so as to interfere with the image reproduction hologram recording medium 6 (hologram). That is, when the image reproduction hologram recording medium 6 is produced by reference light irradiated to the recording medium at an incident angle of 45 ° from a predetermined direction, the emission angle θ2 of the reproduction illumination light 32 is As long as the illumination HOE 5 and the image reproduction hologram recording medium 6 are arranged in parallel, the temperature is set to 45 °. Further, since the hologram illumination device 1 may use a plurality of image reproduction hologram recording media 6 having different recording methods or a hologram recording medium 6 corresponding to a plurality of wavelengths, the emission angle θ2 of the reproduction illumination light 32 is set. , It may be set to include a certain continuous range (for example, 40 ° to 50 °), or it may be set to include a discontinuous emission angle having a plurality of angles.

The illumination HOE5 can be configured to multiplex record a plurality of types of illumination holograms in the same region and reproduce the regenerated illumination light with light of different directions, incident angles or wavelengths. In this case, the light from the light source can be effectively used. Further, in the illumination HOE5, a plurality of types of illumination holograms are multiple-recorded in the same region, and regenerated illumination light having a different direction, an emission angle or a wavelength is reproduced corresponding to light having a different direction, an incident angle or a wavelength. It can also be configured as possible. In this case, different images can be reproduced by multiple-recording different images on the image reproduction hologram recording medium 6. For example, in FIG. 1, in addition to the light source provided on the lower side, a light source is also provided on the upper side, and the lighting HOE5 irradiates the first regenerated illumination light with the light from the lower light source and the upper light source. The image reproduction hologram recording medium 6 is configured to be able to irradiate the second reproduction illumination light with the light from the light source, reproduces the first image by the first reproduction illumination light, and reproduces the first image by the second reproduction illumination light. It is configured to reproduce the image of 2. However, the first regenerated illumination light and the second regenerated illumination light have different directions, emission angles and / and wavelengths.

By the way, in FIG. 1, for the sake of simplicity, only the propagation of light in the XZ plane is dealt with, but in reality, the diffused light from the light source 2 not only propagates in parallel with the XZ plane but also in the XZ plane. On the other hand, there is also light 3 (and incident light 30) that propagates at an angle. However, since the angle selectivity of the illumination HOE5 can be set arbitrarily, it is possible to reproduce the reproduction illumination light 32 by the incident light 30 not included in the XZ plane, depending on the recording method of the illumination hologram. It is also possible to emit the regenerated illumination light 32 that is not included in the XZ plane. The XZ plane includes not only a plane including the XY axis but also a plane parallel to such a plane.

The image reproduction hologram recording medium 6 is formed with an image reproduction hologram in which a stereoscopic image to be displayed is recorded in advance by a predetermined recording method. As the image reproduction hologram formed on the image reproduction hologram recording medium 6, an image reproduction hologram that can be reproduced by the preset reproduction illumination light 32 is recorded. When the reproduction illumination light 32 emitted from the illumination HOE 5 is incident on the image reproduction hologram recording medium 6, the image reproduction hologram recorded on the image reproduction hologram recording medium 6 generates the reproduction light 34 by diffraction. The stereoscopic image 60 is displayed. The apparent position of the stereoscopic image 60 corresponds to the position of the subject at the time of recording. In a hologram recording medium, holograms having different properties can be multiple-recorded at the same position. For example, at the same position, a first image reproduction hologram that interferes with the first reproduction irradiation light and does not interfere with the second reproduction irradiation light and a first reproduction irradiation light that interferes with the second reproduction irradiation light. It is also possible to multiplex record a second image reproduction hologram that does not interfere with the irradiation light.

When the image reproduction hologram recording medium 6 is configured to be replaceable, if the image reproduction hologram recording medium 6 is mistakenly placed up, down, left, or right, the irradiation direction of the reproduction illumination light 32 on the image reproduction hologram recording medium 6 changes, and the image reproduction hologram recording medium 6 is reproduced. There is a risk that it will not be possible. Therefore, it is preferable to provide means for correctly attaching the image reproduction hologram recording medium 6. For example, a mark (color, pattern, etc.) may be attached so that the top of the image reproduction hologram recording medium 6 can be seen, or the shape of the holding means 7 is asymmetrical in the vertical direction and attached in the correct arrangement. It may be configured so that it can be confirmed.

The holding means 7 holds a light source 2, a light guide plate 4, a lighting HOE 5, an image reproduction hologram recording medium 6, and the like. As the holding means 7, a box-shaped housing and a frame can be adopted, and it is preferable that the image reproduction hologram recording medium 6 can be removed and attached by a simple operation. The holding means 7 may be integrally configured with the light guide plate 4 as a display window. In the example shown in FIG. 1, the holding means 7 has a box shape having an opening (display window) only on the front side, but may be configured to have an opening (display window) on the rear side. In this case, an observer (not shown) different from the observer 100 can observe the stereoscopic image from the rear side. Further, a gap for inserting the image reproduction hologram recording medium 6 may be provided on the side surface. Further, the holding means 7 may be provided with a light-shielding member that prevents the incident of external light from the surroundings in the opening for observing the hologram. For example, a plate-shaped light-shielding member overhanging the front side may be provided as an eave around the opening. By reducing the incident of external light by the light-shielding member, the observer can easily observe the hologram reproduced from the image reproduction hologram recording medium 6.

FIG. 2 is another example of the holographic lighting device of the present invention. The hologram lighting device 1 of this example has a different arrangement of the light source 2 and the lighting HOE 5 from the device shown in FIG. Other configurations are the same as those of the apparatus shown in FIG. 1, and thus the description thereof will be omitted.

The light source 2 is arranged on the rear side of the light guide plate 4, and irradiates the end portion of the light guide plate 4 with light (diffused light) 3 having a predetermined wavelength from the rear side. The light 3 from the light source 2 propagates inside the light guide plate 4. Although not shown in FIG. 2, it is preferable to provide an optical system that deflects the light 3 from the light source 2 so that the angle is smaller than the critical angle with respect to the surface of the light guide plate 4.

Unlike the arrangement shown in FIG. 1, the illumination HOE 5 is arranged in contact with the front surface of the light guide plate 4 as a reflective hologram. Of the light 3 propagating inside the light guide plate 4, the illumination HOE 5 reproduces and illuminates the incident light 30 incident on the illumination HOE 5 from the front surface of the light guide plate 4 at a predetermined incident angle θ1 at a predetermined reflection angle θ3. The light 32 is emitted toward the image reproduction hologram recording medium 6. Further, the reproduction illumination light 32 having a reflection angle θ3 is refracted on the rear surface of the light guide plate 4 according to Snell's law, and is emitted from the light guide plate 4 toward the image reproduction hologram recording medium 6 at an emission angle θ4. When the image reproduction hologram recording medium 6 is brought into close contact with the rear surface of the light guide plate 4, the reproduction illumination light 32 having a reflection angle θ3 is incident on the image reproduction hologram recording medium 6. Further, the reflection type HOE5 for illumination has wavelength selectivity, receives light from a light source 2 (for example, a white LED), and emits regenerated illumination light having light of a desired wavelength (red, green, blue). The image reproduction hologram recording medium 6 can be irradiated.

The incident light 30 from the light guide plate 4 to the illumination HOE 5 corresponds to the reference light used at the time of recording the illumination HOE 5, and the incident angle θ1 of the incident light 30 corresponds to the angle of the reference light. The reproduction illumination light 32 of the illumination HOE5 corresponds to the object light used at the time of recording the illumination HOE5, and the reflection angle θ3 or the emission angle θ4 of the reproduction illumination light 32 corresponds to the angle of the object light at the time of recording. The reflection angle θ3 and the emission angle θ4 of the reproduction illumination light 32 need to be set corresponding to the reference light at the time of recording of the image reproduction hologram recording medium 6 (hologram). The reflection angle θ3 of the reproduction illumination light 32 is smaller than the critical angle θc, but the reproduction illumination light 32 emitted from the light guide plate 4 is refracted by Snell's law to increase the angle, so that the angle is constant at the emission angle θ4. It may be set to include a range (eg, 40 ° to 50 °).

As described above, according to the example shown in FIG. 1 or 2, the light from the light source provided inside the device is less likely to be directly irradiated to the observer's eyes, and there is less risk of damaging the observer's eyes. .. Further, according to the example shown in FIG. 1, since the front surface of the light guide plate is formed flat and no protrusions or the like are provided, the stereoscopic image 60 (particularly, apparently appears on the rear side of the hologram recording medium). Visibility when observing the stereoscopic image 60B) is improved. Further, on the front surface of the flat light guide plate, the reproduced light constituting the stereoscopic image 60B is not diffusely reflected or greatly refracted, so that the stereoscopic image with less distortion and deformation can be observed.

In addition, in the example shown in FIG. 1 or 2, since the light from the light source provided inside the apparatus does not reach the observer side, the hologram recording medium may be displayed in a pitch-black display space depending on the recording method of the hologram recording medium. It is also possible to display a plurality of stereoscopic images that emerge back and forth across the position of.

[Structure of light source and light guide plate]
It is preferable that the light from the light source propagates by repeating total reflection inside the light guide plate and does not emit to the front side (observer side) of the light guide plate. Further, it is preferable to provide a parallelizing optical system for converting diffused light from the light source into parallel light at the end of the light guide plate on which the light source is arranged. The parallel light generated by the parallelizing optical system preferably has an angle of the critical angle θc or more.

FIG. 3 is an example of a parallel optical system for a light guide plate. In the case of the example shown in FIG. 3, the light source 2 is arranged on the side (end) of the light guide plate 4, and the light is irradiated toward the side surface of the light guide plate 4. An inclination 41 is formed at the end of the light guide plate 4 in order to refract the diffused light 3 from the light source 2 diagonally downward on the paper surface (direction of the illumination HOE 5). A linear Fresnel lens 42 is provided at the end of the light guide plate 4 on which the inclination 41 is formed. In this example, the diffused light 3 from the light source 2 is converted into the diagonally downward parallel light 30 by the parallel optical system 40 composed of the inclination 41 and the Fresnel lens 42. Further, when a part of the parallel light 30 is reflected by the surface of the light guide plate 4 and propagates to the other end, it is preferable to provide a light absorption unit 43 at the other end of the light guide plate 4. The light absorption unit 43 prevents the parallel light 30 that has reached the other end of the light guide plate 4 from being reflected by the end face and mixed with the observer or the illumination as noise light. The linear Fresnel lens 42 can be made smaller and lighter, but an ordinary cylindrical lens can also be used.

FIG. 4 is another example of the parallel optical system of the light guide plate. In the case of the example shown in FIG. 4, the light source 2 is arranged behind the light guide plate 4. A curved surface is formed at the end of the light guide plate 4 as a parallelizing optical system 40 for converting the diffused light 3 from the light source 2 into parallel light obliquely downward. In this example, the curved surface 40 converts the diffused light 3 from the light source 2 into parallel light 30 diagonally downward on the paper surface.

According to the configuration of the parallel optical system shown in FIGS. 3 and 4, the parallel light 30 that is incident on the surface of the light guide plate at an angle equal to or higher than the critical angle θc can be generated, so that the light from the light source 2 can be emitted. It rarely emits light from the front surface of the light guide plate 4. As a result, the light from the hologram lighting device does not interfere with the observation of the stereoscopic image, and the visibility of the stereoscopic image is improved. In addition, there is no risk of damaging the observer's eyes.

[HOE manufacturing equipment for lighting]
FIG. 5 is an explanatory diagram showing an apparatus and a method for manufacturing a holographic optical element. The fabrication apparatus includes a laser light source 11, a collimating lens 12, a relay lens 13, a beam splitter 14, a first shifting means (first prism) 15, a second shifting means (second prism) 16, and an immersion objective lens 17 (immersion objective lens 17). Lens 18, immersion 19), first displacement amount changing means (first driving means) 21, second displacement amount changing means (second driving means) 22, antireflection means 23, mounting table 24, control means 25. And so on. In addition, although not shown, an expander, an aperture, or the like may be provided as appropriate. The mounting table 24 movably holds the photosensitive material 50 so that the recording target portion of the photosensitive material 50 is aligned with the focal point O of the immersion objective lens 17.

The laser light source 11 is, for example, a semiconductor laser or the like, and is configured to irradiate a coherent laser beam L having the same wavelength as the light source 2 used in the hologram lighting device 1. The beam splitter 14 separates the laser light L into two light beams at the interface, reflects one as the reference light L1 in the first direction (for example, the Z direction), and the other as the object light L2 in the first direction. It transmits in a different second direction (eg, the X direction).

The collimating lens 12 forms the light from the laser light source 11 into substantially parallel light, and the relay lens 13 is a light beam of the laser light L (reference light L1 and object light L2) on the incident pupil surface 20 of the immersion objective lens 17. Is configured to focus at points P1 and P2. The point P1 can be regarded as a point light source of the reference light L1. The point P2 can be regarded as a point light source of the object light L2. The optical system for forming an image on the entrance pupil surface of the objective lens may have another optical system including the collimating lens 12 and the relay lens 13, or a combination other than the collimating lens 12 and the relay lens 13. You may.

The first shifting means (first prism) 15 is arranged on the optical path of the reference light L1 traveling in the first direction, and shifts the imaging point P1 of the reference light L1 in the plane of the entrance pupil surface of the objective lens 17. It is something that makes you. When a prism is used as the first shift means 15, in the arrangement of FIG. 5, it is arranged on the optical path of the reference light L1 traveling in the first direction, and the incident reference light L1 is shifted parallel to the second direction. It is configured to emit light. Further, the displacement amount ΔX can be changed by moving the first prism 15 in the second direction by the first displacement amount changing means (first driving means) 21. In particular, by using a prism, the optical path length can be kept constant even if the displacement amount ΔX is changed. Further, it is preferable that the first displacement amount changing means 21 rotates the first prism 15 around the Z axis so that the point P1 can be shifted also in the Y-axis direction of FIG. That is, it is preferable that the position of the point P1 on the entrance pupil surface of the objective lens is freely configured in the XY directions. With this configuration, it is possible to produce an illumination HOE capable of generating regenerated irradiation light in a fixed direction even with incident light from different directions.

As other shifting means and displacement amount changing means, an optical fiber unit optical system is adopted in which light from a laser light source is emitted through two polarization plane preservation fibers and light diffused from an optical fiber end face is focused by a relay lens. It can also be realized by changing the position of the optical fiber unit optical system.

The second shifting means (second prism) 16 is arranged on the optical path of the object light L2 traveling in the second direction, and shifts the imaging point P2 of the object light L2 in the plane of the entrance pupil surface of the objective lens 17. It is something that makes you. When a prism is used as the second shifting means 16, in the arrangement of FIG. 5, it is arranged on the optical path of the object light L2 traveling in the second direction, and the incident object light L2 is shifted parallel to the first direction. It is configured to emit light. When it is sufficient to reproduce only the illumination light for reproduction at a specific angle, the displacement amount ΔZ is fixed without providing the second displacement amount changing means (second driving means) 22, and the point P2 on the entrance pupil surface is fixed. The displacement amount D2 of the above may be constant, and the same object light may always be emitted. However, in order to make it possible to manufacture a more multifunctional lighting HOE, a second displacement amount changing means (second driving means) 22 is provided so that the position of the point P2 on the entrance pupil surface of the objective lens can be changed. Is preferable. For example, the displacement amount D2 of the point P in the X-axis direction can be changed by moving the second prism 16 in the Z-axis direction by the second driving means 22. With this configuration, it is possible to produce an illumination HOE capable of generating a plurality of regenerated irradiation lights by incident light from different directions. Further, the second displacement amount changing means 22 also rotates the second prism 16 around the X axis in the same manner as the first displacement amount changing means 21, and points P2 in the Y-axis direction of FIG. It is preferable to configure it so that it can be shifted. That is, it is preferable that the position of the point P2 on the entrance pupil surface of the objective lens is freely configured in the XY directions. With this configuration, it is possible to produce an illumination HOE capable of generating a plurality of regenerated irradiation lights in different directions by a plurality of incident lights from different directions.

The first driving means 21 moves the first prism 15 in the X direction by a predetermined shift amount ΔX by the control means 25. The second driving means 22 moves the second prism 16 in the Z direction by a predetermined shift amount ΔZ by the control means 25. Various motors and actuators can be adopted as the first drive means 21 and the second drive means 22. The control means 25 may be configured to realize processing by, for example, executing a program stored in a storage device (memory) by an arithmetic unit (CPU), or a configuration that realizes processing by a logic circuit. You may.

The immersion objective lens 17 is composed of a lens 18 and an immersion liquid 19. The immersion objective lens 17 refracts the reference light L1 from the point light source P1 on the entrance pupil surface 20 and irradiates the reference light L1 toward the focal point O as parallel light having a predetermined angle φ1. Similarly, the immersion objective lens 17 refracts the object light L2 from the point light source P2 on the entrance pupil surface 20 and irradiates the object light L2 toward the focal point O as parallel light having a predetermined angle φ2. Instead of the immersion objective lens, another high numerical aperture lens such as a solid immersion lens may be used.

The photosensitive material 50 is a material on which an illumination hologram is recorded. The antireflection means 23 is a member arranged between the photosensitive material 50 and the mounting table 24 that holds the photosensitive material 50, and the reference light L1 and the object light L2 that have passed through the photosensitive material 50 are reflected and are again photosensitive. It is a means for preventing the material 50 from heading toward the material 50. The antireflection means 23 is preferably composed of a member having a moth-eye structure. The moth-eye structure is a structure having a large number of minute protrusions in nanometer units, and has a function of confining incident light and not reflecting it. It is preferable to use the immersion liquid 26 also between the photosensitive material 50 and the member having the moth-eye structure. By providing the immersion liquid 26, it is possible to prevent the reference light L1 and the object light L2 from being reflected by the reflection due to the critical angle on the surface of the photosensitive material and heading toward the photosensitive material 50 again. In addition, as a simple antireflection means, a black sheet that absorbs light may be used. Also in that case, it is preferable to use the immersion liquid 26 between the black sheet that absorbs light and the photosensitive material 50.

The mounting table 24 holds the photosensitive material 50 (and the antireflection means 23), and can be moved in the XYZ direction by the control means 25 so that the recording target portion of the photosensitive material 50 is aligned with the focal point O of the immersion objective lens 17. It is composed.

[How to make HOE for lighting]
When the HOE for illumination is produced, the laser light L emitted from the laser light source 11 is separated via the beam splitter 14.

One of the separated laser beams L1 becomes reference light (or object light), travels in the first direction (Z direction), is shifted parallel to the X-axis direction through the first prism 15, and is a beam. It passes through the splitter 14 and focuses on the incident pupil surface 20 of the immersion objective lens 17 of the immersion objective lens 17. The point P1 at this time can be regarded as a point light source of the reference light L1. Here, the distance from the point P1 to the central axis M of the immersion objective lens 17 (hereinafter, referred to as a displacement amount) is defined as D1.

The other separated laser beam L2 becomes object light (or reference light), travels in the second direction (X direction), is shifted parallel to the Z-axis direction via the second prism 16, and is beamed. It is reflected by the splitter 14 and focused on the entrance pupil surface 20 of the immersion objective lens 17. The point P2 at this time can be regarded as a point light source of the object light L2. Here, the distance from the point P2 to the central axis M of the immersion objective lens 17 (hereinafter, referred to as a displacement amount) is defined as D2.

The reference light L1 emitted from the point light source P1 is refracted by the immersion objective lens 17 and is irradiated with parallel light having a predetermined angle φ1 toward the focal point O. The predetermined angle φ1 is an amount that depends on the displacement amount D1. Further, the displacement amount D1 is determined by the shift amount ΔX of the first prism 15. Therefore, the present manufacturing apparatus can control the angle φ1 of the reference light L1 to a desired value by appropriately setting the shift amount ΔX of the first prism. The angle φ1 of the reference light L1 corresponds to the incident angle θ1 of the incident light 30 incident on the illumination HOE from the light guide plate shown in FIG. φ1 preferably includes an angle larger than the critical angle θc in relation to the critical angle θc in the light guide plate. Since refraction at the interface of the hologram recording medium is suppressed by immersion liquid, it is preferable to set 45 ° <φ1 <90 °.

The object light L2 emitted from the point light source P2 is refracted by the immersion objective lens 17, and parallel light having a predetermined angle φ2 is irradiated toward the focal point O. The predetermined angle φ2 is an amount that depends on the displacement amount D2. Further, the displacement amount D2 is determined by the shift amount ΔZ of the second prism 16. Therefore, the present manufacturing apparatus can control the angle φ2 of the object light L2 to a desired value by appropriately setting the shift amount ΔZ of the second prism. The angle φ2 of the object light L2 is set to the emission angle θ2 of the reproduction illumination light 32 emitted from the illumination HOE shown in FIG. 1 or the like, or the reflection angle θ3 of the reproduction illumination light 32 reflected from the illumination HOE shown in FIG. It will be the corresponding one. φ2 is set corresponding to the reproduction reference light in the image reproduction hologram of the image reproduction hologram recording medium 6, and is preferably set to, for example, 40 to 50 °. Further, as shown in FIG. 2, when the regenerated illumination light 32 emitted from the light guide plate 4 is refracted by Snell's law on the rear surface of the light guide plate 4 to increase the angle and is emitted at an emission angle θ4, the object light L2 The angle φ2 of is set in consideration of refraction.

Here, in the apparatus for producing the lighting HOE of the present invention, the immersion objective lens 17 is used, and the space between the objective lens main body 18 and the photosensitive material 50 to be recorded is filled with the immersion liquid 19. As a result, the difference in the refractive index between the objective lens body 18 and the immersion liquid 19 and the difference in the refractive index between the immersion liquid 19 and the photosensitive material 50 are reduced to an acceptable level, so that the angle of the reference light L1 The angle φ2 of φ1 and the object light L2 can be precisely controlled to be a desired angle. In particular, since the angle φ1 of the reference light needs to be larger than the critical angle θc of the light guide plate, an objective lens having a high aperture ratio such as an immersion objective lens is required.

When the reference light L1 and the object light L2 intersect at the focal point O, the recording target portion of the photosensitive material 50 corresponding to the position of the focal point O is subjected to the reference light L1 irradiated at an angle φ1 and the object light L2 irradiated at an angle φ2. Interference fringes are formed by the light, and a hologram for illumination is recorded.

Then, by repeating the above-mentioned hologram recording process while sequentially moving the recording position of the photosensitive material 50, the lighting HOE shown in FIG. 1 and the like can be produced. It is also possible to record a plurality of holograms having different angle selectivity at the same position of the photosensitive material. Therefore, according to this manufacturing method, it is possible to manufacture an illumination HOE that emits (or reflects) light incident in a certain angle range as regenerated illumination light having a specific angle. In this example, although the setting of the angle selectivity of the hologram has been mainly described, a holographic optical element having desired diffraction efficiency, wavelength selectivity and the like can also be manufactured by various methods.

As described above, in the present manufacturing apparatus and the manufacturing method, the reference light and the object light separated into the two luminous fluxes are provided with a distance (in other words, a displacement amount D1 + D2 or a distance from the point P1 to the point P2). The photosensitive material can be irradiated with light and object light at a desired angle of incidence. Further, by appropriately moving the two prisms, such a desired angle can be easily changed. Further, depending on the configuration of the immersion objective lens, the error of the angle of incidence on the photosensitive material can be reduced. Since the antireflection means having a moth-eye structure is adopted, the light that has passed through the photosensitive material is absorbed and unnecessary reflection is not generated, which is preferable.

[Example]
FIG. 6 is an example of the configuration of the light source and the light guide plate in the hologram lighting device of the present invention. FIG. 6A is a side view of the light source and the light guide plate as viewed from the width direction (Y direction) of the device. FIG. 6B is a top view of the light source and the light guide plate as viewed from the thickness direction (Z direction) of the device.

In this example, three LEDs (LUMILED LUXEON Z manufactured by Philips) were used for the light source 2, and a glass plate was used for the light guide plate 4. An inclination of 22 ° with respect to the normal of the glass plate was formed at the end of the glass plate 4 on which the LED 2 is arranged, and a linear Fresnel lens 42 was arranged between the LED 2 and the end of the glass plate 4. .. The light 3 emitted from the LED 2 (indicated by a thin solid line in the figure) is converted into substantially parallel light via the linear Fresnel lens 42 and incident obliquely downward on the paper surface.

The glass plate 4 has a height of 85 mm, a width of 33 mm, and a thickness of 12 mm. As shown in the configuration of the light source and the glass plate shown in FIG. 6, the light guide plate that can be used in the hologram lighting device of the present invention can be sufficiently thin compared to the height × width of the device. .. When a hologram lighting device is manufactured by combining the structure of the light source and the glass plate with other configurations (lighting HOE, holding means, etc.), the hologram lighting device can realize a thickness of 13 to 18 mm. The width of the device can be increased by increasing the number of LEDs.

As described above, although a plurality of embodiments have been described in the present specification, the scope of application of the present invention is not limited to the respective embodiments. For example, these plurality of forms can be combined.

1 Hologram lighting device 2 Light source 4 Light guide plate 5 HOE for lighting
6 Hologram recording medium for image reproduction 7 Holding means 10 Hologram display device 30 Incident light 32 Reproduction illumination light 34 Reproduction light 40 Parallel optical system 60 Solid image 100 Observer

Claims (6)

A light guide plate having a refractive index higher than that of air and a light guide plate provided in contact with the light guide plate, propagating in the light guide plate, and receiving at least a part of light incident at an angle larger than the critical angle of the light guide plate with respect to air. This is a method for manufacturing a hologram lighting device including a holographic optical element for lighting that generates regenerated illumination light.
Place the photosensitive material of the holographic optics for illumination so that it is located at the focal point of the high numerical aperture objective lens.
The light from the light source is separated into two luminous fluxes to generate the first light and the second light.
The high-aperture objective lens is subjected to the high-aperture number of the first light so as to pass through a first point separated by a first displacement amount from the central axis of the high-aperture number objective lens. The objective lens is irradiated with the first light refracted at the first angle corresponding to the first displacement amount, and the photosensitive material is irradiated with the second light from the central axis of the high aperture number objective lens. The second light is applied to the high-aperture objective lens so as to pass through a second point separated by a displacement amount, and the second light is refracted at a second angle corresponding to the second displacement amount . A step of irradiating the photosensitive material with the light of 2 and recording a hologram for illumination to produce a holographic optical element for illumination.
It has a step of arranging the holographic optical element for illumination on which the hologram for illumination is recorded in contact with the light guide plate.
The first angular degree is a method for manufacturing a hologram illumination device, characterized in that the angle larger than the critical angle of the light guide plate. The high NA objective lens is an immersion objective lens, making how the hologram illumination device according to claim 1, characterized in that in contact with the photosensitive material through the immersion liquid. The fabrication of the hologram lighting device according to claim 1 or 2 , wherein the first displacement amount is changed by moving the first prism provided on the optical path of the first light. mETHODS. Preparation how the hologram illumination device according to any one of claims 1 to 3, wherein placing the anti-reflection means having a moth-eye structure downstream of the photosensitive material. Change the first displacement and the second displacement amount, any one of claims 1 to 4, characterized in that for recording a plurality of holograms having different angular selectivity at the same position of the photosensitive material Preparation how the hologram illumination device according to paragraph 1. As the first light, the photosensitive material is irradiated with parallel light at the first angle, and as the second light, the photosensitive material is irradiated with parallel light at the second angle. Preparation how the hologram illumination device according to any one of claims 1 to 5, characterized in.

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