JP2020038383A - Method for producing lighting device for holograms and method for producing holographic optical element - Google Patents

Abstract

To provide a device for producing a holographic element for illumination used in a lighting device for holograms which is thin and light and convenient to carry with.SOLUTION: The present invention comprises: a light source 11; a beam splitter 14 for separating light from the light source into two beams; a high-aperture objective lens; an optical system for forming the image of light from the light source as a point light source on the entrance pupil surface of a high-aperture objective lens 17; first shift means 15 for causing the image-forming position on the entrance pupil surface to be displaced within the entrance pupil surface and arranged on an optical path of one of the two beams separated by the beam splitter; second shift means 16 for causing the image-forming position on the entrance pupil surface to be displaced within the entrance pupil surface and arranged on the optical path of the other; and displacement amount change means 21 for changing the amount of displacement of the image-forming position by the first shift means; and a placement table 24 for holding a photosensitive material 50.SELECTED DRAWING: Figure 5

Description

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

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

  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 light reaction occurs in the hologram recording layer of the photosensitive material, and the hologram is fixed as interference fringes. When the hologram is irradiated with light (reproduction illumination light) corresponding to the reference light at the time of recording, diffraction occurs, and light (reproduction light) corresponding to the object light at the time of recording is generated. Thereby, the observer can observe the three-dimensional image recorded on the hologram. As the reference light at the time of recording, a laser beam having coherence is generally used, so that the reproduction illumination light used at the time of reproduction also requires the same wavelength and the same incident angle as the reference light at the time of recording. With high irradiation conditions.

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

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

JP 2009-245803 A JP 2009-69527 A

  The illumination device described in Patent Literature 1 can irradiate substantially parallel light to a rectangular irradiation region. It has also been proposed to configure a lighting system capable of irradiating a wide range by connecting a plurality of irradiation devices. However, when trying to irradiate substantially parallel light to a hologram recording a stereoscopic image, it is necessary to strictly adjust the angle and position of the illumination device. Depending on the surrounding environment, the installation place of the lighting device may be limited.

  Patent Literature 1 also discloses a hologram illuminating device that defines the positional relationship between a light source and a hologram. However, such a device is large and large in volume, so it is not suitable for carrying, and is not suitable for installation. Requires a certain 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 configuration in which the substantially parallel light is emitted from the LED and the Fresnel lens is adopted, the area of the substantially parallel light irradiation is limited. Therefore, the size of the applicable hologram sheet is limited, and it is difficult to display a relatively large stereoscopic image. Furthermore, since the arm holding the LED projects above the hologram observation area, it hinders observation of a three-dimensional image, and furthermore, the arm itself becomes a projection, impairing the appearance of an exhibition booth or the like. .

  In addition, in the devices described in Patent Literatures 1 and 2, the high-output illumination light of the illumination device may be reflected on the hologram surface or each part of the device. The observer may hurt his eyes. Further, there is a possibility that the frame or the body to which the high-power irradiation light is constantly irradiated is deteriorated by heat.

  As described above, a special illuminator is required for reproducing the hologram. However, the conventional illuminating device has various problems, and there has been no illuminating device having a thin, lightweight, and simple configuration suitable for hologram reproduction. This is one factor that hinders the use and spread of holograms.

  The present invention has been made in view of the above-described problems, and has as its object to provide a hologram illumination device and a hologram display device that can solve at least a part of the problems. Another object of the present invention is to provide a manufacturing apparatus and a manufacturing method of a lighting holographic element used in such an apparatus.

  In order to solve the above-described problem, the hologram illumination device of the present invention is a light source, a light guide plate that propagates light from the light source, and receives at least a part of the light that propagates through the light guide plate to form a three-dimensional image. A holographic optical element for illumination that irradiates a recorded illumination reproduction hologram with reproduction illumination light at a predetermined angle, and a holding unit that holds the light guide plate, the illumination holographic optical element, and the image reproduction hologram. , Is provided.

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

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

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

  The hologram display device according to the present invention is characterized in that an image reproduction hologram for reproducing a three-dimensional image by the reproduction illumination light at the predetermined angle is attached to the hologram illumination device.

  The holographic optical element manufacturing apparatus according to 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 the light from the light source incident on the high numerical aperture objective lens. An optical system that forms an image as a point light source on the pupil plane, and is arranged on one optical path of the two light beams separated by the beam splitter, and forms an imaging position on the entrance pupil plane of the high numerical aperture objective lens within the entrance pupil plane. A first shift means for displacing, and a second shift means disposed on the other optical path of the two light beams separated by the beam splitter, for displacing an image forming position on the entrance pupil plane of the high numerical aperture objective lens in the entrance pupil plane. Shift means, displacement amount changing means for changing the amount of displacement of the imaging position by the first shift means, a mounting table for holding the photosensitive material, and a reflection means provided between the mounting table and the photosensitive material. Characterized in that it comprises a stop means.

  In the holographic optical element manufacturing apparatus, it is preferable that the antireflection unit has a moth-eye structure.

  According to the method of manufacturing the illumination holographic optical element of the present invention, the photosensitive material of the illumination holographic optical element is arranged so as to be in contact with the immersion objective lens through the immersion liquid, and the light from the light source is separated into two light beams. Then, to generate reference light and object light, on the entrance pupil plane of the immersion objective lens, so as to pass through a first point separated by a first displacement from the central axis of the immersion objective lens, By irradiating the reference light to the immersion objective lens, the reference light refracted at a first angle corresponding to the first displacement amount is used as the photosensitive material, and the reference light is projected from a central axis of the immersion objective lens. Irradiating the object light to the immersion objective lens so as to pass through a second point separated by a displacement amount of 2 and the object light refracted at a second angle corresponding to the second displacement amount Is irradiated on the photosensitive material.

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

  According to the present invention, it is possible to provide a hologram illuminating device or hologram display device which 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 an embodiment of the present invention.

Schematic configuration diagram of the hologram illumination device of the present invention Another example of the hologram illumination device of the present invention Example of collimating optical system of light guide plate Another example of collimating optical system of light guide plate Example of hologram recording method Embodiment of Configuration of Light Source and Light Guide Plate of the Present Invention

  The present invention provides a conventional optics such as a conventional Fresnel lens or collimator lens configured to irradiate a substantially parallel light at a predetermined angle as a means for irradiating a 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 light propagating through the light guide plate at a predetermined angle is employed.

Hereinafter, such a holographic optical element is referred to as “illumination holographic optical element (illumination HOE)”, and a hologram for generating reproduction illumination light recorded on the illumination HOE is referred to as “illumination hologram”. A hologram for reproducing a three-dimensional image to be displayed is referred to as an “image reproducing hologram”, and a medium on which an image reproducing hologram is recorded or formed is referred to as an “image reproducing hologram recording medium”.

  The hologram illuminating device of the present invention has a thin flat plate shape, is lightweight, and is configured to be portable (hereinafter, see FIG. 1 or FIG. 2). When the dimensions of the hologram illumination device 1 are represented by a height (X direction), a width (Y direction) and a thickness (Z direction), the dimension of the plane defined by height × width is used as a reference. With respect to the line N, an incident angle, an output angle, a reflection angle, and the like, which will be described later, are defined. Further, the direction in which light travels on the XY plane is referred to as “azimuth”. Also, the side where the observer 100 is located is referred to as “front side” and the side opposite to the observer 100 is referred to as “rear side” with respect to the plane of the hologram illumination device.

  The hologram illumination device 1 of the present invention receives at least a light source 2, a light guide plate 4 that propagates light 3 from the light source 2, and at least a part of the light 3 that propagates in the light guide plate 4, and performs image reproduction. An illumination HOE 5 that irradiates the reproduction illumination light 32 at a predetermined angle toward the hologram recording medium 6 and a holding unit 7 that holds the HOE 5 in a predetermined positional relationship are provided. It is preferable that the hologram illumination device 1 is configured so that the hologram recording medium 6 for image reproduction can be easily removed and attached. Further, the hologram display device 10 may be used with the hologram recording medium 6 for image reproduction attached to the hologram illumination device 1.

  The illumination HOE 5 receives the light from the light source 2 propagating through the light guide plate 4 and irradiates the attached image reproduction hologram recording medium 6 with reproduction illumination light 32 at a predetermined angle. Are formed. Further, when the illumination HOE 5 is arranged on the front side of the hologram recording medium 6 for image reproduction, it can pass the reproduction light 34 reproduced from the hologram recording medium 6 for image reproduction to the front side. Further, a plurality of illumination holograms may be multiplex-recorded on the illumination HOE 5 so as to overlap with each other, and one type of reproduction illumination light may be reproduced by light having different directions, incident angles, and wavelengths. Alternatively, a configuration may be employed in which a plurality of reproduction illumination lights can be reproduced by light having different directions, incident angles, and wavelengths.

  In the hologram illuminating device 1 or the hologram display device 10, the light guide plate 4, the illuminating HOE 5, and the image reproducing hologram recording medium 6 can be arranged in an appropriate order according to the form of use. For example, the HOE 5 for illumination can be of a transmission type or a reflection type, and when the transmission type is adopted, the HOE 5 for illumination is arranged on the rear side of the light guide plate 4 (see FIG. 1), and the reflection type is adopted. In this case, the lighting HOE 5 can be arranged in front of the light guide plate 4 (see FIG. 2). Further, the image reproducing hologram recording medium 6 can also be of a transmission type or a reflection type, and can be appropriately arranged. For example, the hologram recording medium 6 for image reproduction may be arranged on the front side of the light guide plate 4 or on the rear side. The illumination HOE 5 and the image reproduction hologram recording medium 6 are preferably arranged in parallel, but it is sufficient that the reproduction illumination light 32 is applied to the image reproduction hologram recording medium 6 at a desired angle. It is not necessary to arrange them in parallel depending on the situation.

  When predetermined reproduction illumination light 32 is applied to the image reproduction hologram recording medium 6, reproduction light 34 is generated, and the hologram illumination device 1 or the hologram display device 10 displays a stereoscopic image 60. The apparent position of the three-dimensional image 60 corresponds to the position of the subject when recording the hologram. For this reason, according to the present invention, according to the hologram recording method, the stereoscopic image 60A can be apparently displayed on the front side of the hologram illumination device 1, and the stereoscopic image 60B can be displayed on the rear side. It can also be configured to be performed. In other words, the configuration may be such that the observer 100 can directly observe the three-dimensional image 60A in front of the hologram recording medium 6 for image reproduction, or (the hologram for image reproduction) may be arranged behind the hologram recording medium 6 for image reproduction. The configuration may be such 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 including the same wavelength as the reference light used when recording the HOE 5 for illumination, and is an ultra-small fluorescent tube for an LED, a xenon lamp, a semiconductor laser, an organic EL element, and a liquid crystal backlight. Etc. can be adopted. The light source 2 is preferably provided at an 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 behind 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 using the hologram illumination device 1 according to the mode of use of the hologram illumination device 1. Alternatively, they may be arranged apart from the light guide plate 4. Further, a plurality of light sources 2 may be arranged. Furthermore, the light source 2 may be arranged at the center of the light guide plate 4 as long as the observation of the stereoscopic image 60 is not hindered. Conventionally, to illuminate a square hologram recording medium using a circular illumination device with a bright central part, it was necessary to illuminate from a distance obliquely upward to an extra part around the hologram recording medium, In the hologram illuminating device 1 of the present invention, the parallel light having the same angle is converted into the size of the hologram recording medium for image reproduction from the vicinity of the hologram recording medium 6 for image reproduction by the HOE 5 for illumination in a state where illuminance unevenness is small. Since the illumination light can be irradiated as the reproduction illumination light 32, the light source 2 having a weak output of 50% or less as compared with the related art (for example, the Hollolight (registered trademark) parallel illumination type HL01 or the like) can be employed.

  ADVANTAGE OF THE INVENTION According to this invention, the illumination device for holograms which is thin and lightweight and is easy to carry can be provided. In addition, by adopting the configuration of the illumination HOE and the light guide plate, it is possible to irradiate the hologram recording medium with reproduction illumination light at a predetermined angle, and it is not necessary to perform strict alignment, setting of irradiation conditions, and the like. In addition, the size of the illumination HOE and the size of the light guide plate can be appropriately set according to the size of the hologram recording medium to be displayed. Can be uniformly irradiated. Unlike the conventional illuminating device, the hologram illuminating 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. Further, since there is no need for an arm or the like that protrudes into the observation area, the visibility of the three-dimensional image is improved, and the appearance of the apparatus is not spoiled. Further, once the master is manufactured, the lighting HOE can be easily mass-produced by duplicating the master, 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 illumination device of the present invention. The hologram illumination device 1 includes a light source 2, a light guide plate 4, an illumination HOE 5, and holding means 7 for holding these. The hologram illuminating device 1 may be configured so that the hologram recording medium 6 for image reproduction separately manufactured can be attached and detached by a simple operation via the holding means 7. Thus, for example, the user can carry the hologram illumination device 1 to an exhibition hall or the like, and can sequentially replace a plurality of image reproduction hologram recording media 6 according to the purpose in the exhibition hall or the like.

  On the other hand, it is also possible to use the hologram display device 10 with the hologram recording medium 6 for image reproduction attached to the hologram illumination device 1. In this case, the hologram display device 10 can be used, for example, like a picture frame containing a painting work, and constantly displays a three-dimensional image.

  The light source 2 is a light source that can emit light including the same wavelength as the reference light used when recording the illumination HOE 5, and can employ an LED or the like. The light source 2 is arranged so that light enters 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 of the light guide plate 4 or may be arranged away from the end of the light guide plate 4. The light source 2 irradiates light (diffused light) 3 having a predetermined wavelength into the light guide plate 4. When the diffused light from the light source 2 enters 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. For this reason, it is preferable that the light source 2 be 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 transmitting the light 3 from the light source 2 and may employ a light-transmitting material such as glass or resin. The front surface of the light guide plate 4 is preferably flat. Accordingly, the surrounding external light is not irregularly reflected on the front surface of the light guide plate 4, so that the observer 100 is less likely to hinder the observation of the stereoscopic image 60. Also, light propagating inside the light guide plate 4 is not irregularly reflected on the front surface, so that the propagation efficiency can be improved.

Of the light from the light source 2 on the front surface of the light guide plate 4, the light incident at a critical angle θc or more is reflected rearward by total reflection. The critical angle θc is an angle defined by the refractive index between the light guide plate 4 and air. On the other hand, part of the light incident at an angle smaller than the critical angle θc is emitted toward the front side (observer side) at an emission angle defined by the relationship with the refractive index. For this reason, it is preferable that the light source 2 is arranged or configured such that light having an angle smaller than the critical angle θc is not directly radiated toward the front surface of the light guide plate 4. Thereby, since the light from the light source is not irradiated to the observer side, the light source itself does not hinder the observation as compared with the case where the light source is provided outside the apparatus, and the observer 100 Less likely to damage your 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.

  The illumination HOE 5 is a kind of optical element in which an illumination hologram having a deflecting function is formed on a photosensitive material. In the present embodiment, the illumination HOE 5 is disposed in contact with the rear surface of the light guide plate 4 as a transmission hologram. When the incident light 30 enters the illumination HOE 5 from the rear surface of the light guide plate 4 to the illumination HOE 5 at a predetermined angle of incidence θ1 of the light 3 propagating inside the light guide plate 4, the illumination HOE 5 The reproduction illumination light 32, which is parallel light having a predetermined emission angle θ2, reproduces and irradiates the hologram recording medium 6 for image reproduction.

The illumination hologram of the illumination HOE 5 records interference fringes formed by interference between object light and reference light, and is irradiated with light of the same incident angle and the same wavelength from the same direction as the reference light. , And reproduces and emits light having the same wavelength in the same direction and at the same angle as the object light. Therefore, as the object light, a predetermined azimuth (from the top to the bottom in FIG. 1) from the front side to the rear side of the illumination HOE 5 so that the object light travels in the same direction as the reproduction irradiation light 32 and at the same angle. Then, parallel light having an incident angle θ2 is irradiated. Further, as the reference light, the light of the wavelength emitted from the light source 2 from the front side to the rear side of the illumination HOE 5 corresponding to the incident light 30 incident on the illumination HOE 5 from the light guide plate 4 is incident angle θ1. Irradiation. 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 a range of 0 ° <θ1 <90 °. When most of the light propagating inside the light guide plate 4 repeats total 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 configured to have a small thickness, the incident angle θ1 is preferably set to 50 ° <θ1 <90 °. Further, 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 HOE 5 for illumination. The thickness of the hologram recording medium of the HOE 5 for illumination is about 1 to 500 μm, but is preferably 2 to 20 μm when the angle selectivity is weakened.

  The reproduction illumination light 32 from the illumination HOE 5 corresponds to the object light used when recording the illumination HOE 5, and the emission angle θ2 of the reproduction illumination light 32 corresponds to the angle of the object light. It is necessary to set the emission angle θ2 of the reproduction illumination light 32 so as to interfere with (the hologram of) the hologram recording medium 6 for image reproduction. That is, when the hologram recording medium for image reproduction 6 is made of the reference light applied to the recording medium at a 45 ° incident angle from a predetermined direction, the emission angle θ2 of the reproduction illumination light 32 is The angle is set to 45 ° as long as the illumination HOE 5 and the image reproduction hologram recording medium 6 are arranged in parallel. Further, in the hologram illumination device 1, there are cases where a plurality of hologram recording media 6 for image reproduction and hologram recording media 6 corresponding to a plurality of wavelengths, which are different in recording method, are used. May be set so as to include a certain continuous range (for example, 40 ° to 50 °), or may be set so as to include a discontinuous emission angle having a plurality of angles.

  The illumination HOE 5 can be configured so that multiple types of illumination holograms are multiplex-recorded in the same area, and reproduced illumination light is reproduced by light having different directions, incident angles, or wavelengths. In this case, the light from the light source can be used effectively. In addition, in the HOE 5 for illumination, a plurality of types of illumination holograms are multiplex-recorded in the same area, and reproduced illumination light having different directions, emission angles or wavelengths corresponding to lights having different directions, incident angles or wavelengths is reproduced. It can also be configured as possible. In this case, different images can be reproduced by multiplex-recording different images on the hologram recording medium 6 for image reproduction. 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 illumination HOE 5 irradiates the first reproduction illumination light with the light from the lower light source. Hologram recording medium 6 for image reproduction reproduces a first image by the first reproduction illumination light, and reproduces the first image by the second reproduction illumination light. 2 are reconstructed. However, the first reproduction illumination light and the second reproduction illumination light have different orientations, emission angles, and / or wavelengths.

  By the way, in FIG. 1, for simplicity, only the propagation of light in the XZ plane is dealt with, but in practice, the diffused light from the light source 2 propagates not only in the XZ plane but also in the XZ plane. There is also light 3 (and incident light 30) that propagates at an angle to it. However, the illumination HOE 5 can arbitrarily set the angle selectivity, so that the reproduction illumination light 32 can be reproduced by the incident light 30 not included in the XZ plane according to the recording method of the illumination hologram. Alternatively, it is possible to emit the reproduction illumination light 32 not included in the XZ plane. The XZ plane includes not only a plane including the XY axes but also a plane parallel to the plane.

  On the hologram recording medium 6 for image reproduction, a hologram for image reproduction in which a stereoscopic image to be displayed is recorded in advance by a predetermined recording method is formed. As an image reproduction hologram formed on the image reproduction hologram recording medium 6, an image reproduction hologram reproducible by a preset reproduction illumination light 32 is recorded. When the reproduction illumination light 32 emitted from the illumination HOE 5 enters the image reproduction hologram recording medium 6, the image reproduction hologram recorded on the image reproduction hologram recording medium 6 generates a 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 the hologram recording medium, holograms having different properties can be multiplex-recorded at the same position. For example, at the same position, a first image reproduction hologram that interferes with the first reproduction irradiation light but does not interfere with the second reproduction irradiation light, and interferes with the second reproduction irradiation light to perform the first reproduction Multiple recording can be performed with a second hologram for image reproduction that does not interfere with the irradiation light.

  When the hologram recording medium for image reproduction 6 is configured to be replaceable, if the hologram recording medium for image reproduction 6 is upside down and left and right, the irradiation direction of the reproduction illumination light 32 to the hologram recording medium for image reproduction 6 changes, and the reproduction is performed. It may not be possible. Therefore, it is preferable to provide a means for correctly attaching the hologram recording medium 6 for image reproduction. For example, a mark (color, pattern, etc.) may be attached so that the upper part of the hologram recording medium 6 for image reproduction can be seen. You may comprise so that it can confirm.

  The holding unit 7 holds the light source 2, the light guide plate 4, the illumination HOE 5, the hologram recording medium 6 for image reproduction, and the like. It is preferable that the holding means 7 can adopt a box-shaped housing or frame, and can detach and attach the hologram recording medium 6 for image reproduction by a simple operation. The holding means 7 may be configured integrally with the light guide plate 4 as a display window. In the example shown in FIG. 1, the holding means 7 is a box type 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 hologram recording medium for image reproduction 6 may be provided on the side surface. Further, the holding means 7 may be provided with a light-blocking member for preventing external light from entering from surroundings in an opening for observing the hologram. For example, a plate-shaped light shielding member that protrudes forward around the opening may be provided as an eave. By reducing the incidence of external light by the light shielding member, the observer can easily observe the hologram reproduced from the hologram recording medium 6 for image reproduction.

  FIG. 2 shows another example of the hologram illumination device of the present invention. The hologram illumination device 1 of this example is different from the device shown in FIG. 1 in the arrangement of the light source 2 and the illumination HOE 5. Other configurations are the same as those of the device shown in FIG.

  The light source 2 is disposed on the rear side of the light guide plate 4 and irradiates light (diffused light) 3 having a predetermined wavelength to the end of the light guide plate 4 from the rear side. 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 to an angle 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 reflection hologram. The illumination HOE 5 reproduces the incident light 30 incident on the illumination HOE 5 from the front surface of the light guide plate 4 into the illumination HOE 5 at a predetermined incident angle θ1 of the light 3 propagating inside the light guide plate 4 at a predetermined reflection angle θ3. The light 32 is emitted toward the image reproduction hologram recording medium 6 as light 32. Further, the reproduction illumination light 32 having the reflection angle θ3 is refracted on the rear surface of the light guide plate 4 according to Snell's law, and emitted from the light guide plate 4 toward the hologram recording medium 6 for image reproduction 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 enters the image reproduction hologram recording medium 6. Further, the reflection-type illumination HOE 5 has wavelength selectivity, receives light from the light source 2 (for example, a white LED), and generates reproduction illumination light having light (red, green, and blue) of a desired wavelength. The hologram recording medium 6 for image reproduction can be irradiated.

The incident light 30 from the light guide plate 4 to the illumination HOE 5 corresponds to the reference light used when 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 HOE 5 corresponds to the object light used when recording the illumination HOE 5, and the reflection angle θ3 or the emission angle θ4 of the reproduction illumination light 32 corresponds to the angle of the object light during recording. The reflection angle θ3 and the emission angle θ4 of the reproduction illumination light 32 need to be set in correspondence with the reference light at the time of recording (the hologram of) the hologram recording medium 6 for image reproduction. The reflection angle θ3 of the reproduction illumination light 32 is smaller than the critical angle θc. However, since the reproduction illumination light 32 emitted from the light guide plate 4 is refracted by Snell's law and increases in angle, it is constant at the output angle θ4. It may be set to include a range (for example, 40 ° to 50 °).

  As described above, according to the example shown in FIG. 1 or FIG. 2, the light from the light source provided inside the apparatus is less likely to be directly irradiated to the eyes of the observer, and the possibility of damaging the eyes of the observer is reduced. . Further, according to the example shown in FIG. 1, the front surface of the light guide plate is formed flat and has no projections, so that the three-dimensional image 60 (particularly, apparently appears behind the hologram recording medium). The visibility when observing the stereoscopic image 60B) is improved. Also, on the front surface of the flat light guide plate, the reproduced light constituting the three-dimensional image 60B is not irregularly reflected or largely refracted, so that a three-dimensional image with little distortion and deformation can be observed.

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

[Configuration 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. In addition, it is preferable to provide a collimating optical system that converts diffused light from the light source into parallel light at an end of the light guide plate where the light source is disposed. It is preferable that the parallel light generated by the parallelizing optical system has an angle equal to or larger than the critical angle θc.

  FIG. 3 is an example of a parallelizing optical system of the 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 emits light toward the side surface of the light guide plate. An inclination 41 is formed at an end of the light guide plate 4 in order to refract the diffused light 3 from the light source 2 obliquely downward (in the direction of the illumination HOE 5) on the paper surface. Then, a linear Fresnel lens 42 is provided at the end of the light guide plate 4 where the slope 41 is formed. In this example, the diffused light 3 from the light source 2 is converted into the obliquely downward parallel light 30 by the parallelizing optical system 40 including the inclination 41 and the Fresnel lens 42. When a part of the parallel light 30 is reflected on the surface of the light guide plate 4 and propagates to the other end, it is preferable to provide the light absorbing portion 43 at the other end of the light guide plate 4. The light absorbing part 43 prevents the parallel light 30 arriving at the other end of the light guide plate 4 from being reflected at the end face and mixed into the observer or illumination as noise light. The linear Fresnel lens 42 can be made small and lightweight, but an ordinary cylindrical lens can also be used.

  FIG. 4 is another example of the parallelizing optical system of the light guide plate. In the case of the example shown in FIG. 4, the light source 2 is arranged on the rear side of the light guide plate 4. A curved surface is formed at an 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 obliquely downward parallel light. In this example, the diffused light 3 from the light source 2 is converted by the curved surface 40 into parallel light 30 obliquely downward on the paper surface.

According to the configuration of the collimating optical system shown in FIGS. 3 and 4, it is possible to generate the parallel light 30 that is incident on the surface of the light guide plate at an angle equal to or greater than the critical angle θc. Light is less likely to be emitted from the front surface of the light guide plate 4. Thus, the light from the hologram illumination device does not hinder the observation of the stereoscopic image, and the visibility of the stereoscopic image is improved. Also, there is no risk of damaging the eyes of the observer.

[Lighting HOE manufacturing equipment]
FIG. 5 is an explanatory view showing an apparatus and a method for manufacturing a holographic optical element. The manufacturing apparatus includes a laser light source 11, a collimating lens 12, a relay lens 13, a beam splitter 14, a first shift unit (first prism) 15, a second shift unit (second prism) 16, and an immersion objective lens 17 ( Lens 18, immersion liquid 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. Although not shown, an expander, an aperture, and the like may be appropriately provided. The mounting table 24 movably holds the photosensitive material 50 so that the recording target portion of the photosensitive material 50 is in focus 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 emit coherent laser light L having the same wavelength as the light source 2 used in the hologram illumination device 1. The beam splitter 14 separates the laser light L into two light beams at the boundary surface, reflects one of the laser light L as the reference light L1 in the first direction (for example, the Z direction), and reflects the other as the object light L2. The light is transmitted in a different second direction (for example, the X direction).

  The collimating lens 12 shapes the light from the laser light source 11 into substantially parallel light, and the relay lens 13 emits the light flux of the laser light L (the reference light L1 and the object light L2) on the entrance pupil plane 20 of the immersion objective lens 17. Is focused on the 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. Note that the optical system that forms an image on the entrance pupil plane of the objective lens may include another optical system including the collimator lens 12 and the relay lens 13 or a combination other than the collimator lens 12 and the relay lens 13. You may.

  The first shift means (first prism) 15 is arranged on the optical path of the reference light L1 traveling in the first direction, and shifts the image forming point P1 of the reference light L1 in the plane of the entrance pupil plane of the objective lens 17. It is to let. When a prism is used as the first shift means 15, in the arrangement shown in FIG. 5, it is arranged on the optical path of the reference light L1 traveling in the first direction, and shifts the incident reference light L1 in parallel with the second direction. And is emitted. Further, the first displacement amount (X) 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 be configured to rotate the first prism 15 about the Z axis and shift the point P1 also in the Y axis direction in FIG. That is, it is preferable to freely configure the position of the point P1 on the entrance pupil plane of the objective lens in the XY directions. With this configuration, it is possible to manufacture an illumination HOE that can generate reproduction irradiation light in a certain direction even by incident light from different directions.

  As other shift means and displacement amount changing means, an optical fiber unit optical system that emits light from a laser light source through two polarization preserving fibers and condenses light diffused from an end face of the optical fiber by a relay lens is adopted. This can be realized by changing the position of the optical system of the optical fiber unit.

  The second shift means (second prism) 16 is arranged on the optical path of the object light L2 traveling in the second direction, and shifts the image forming point P2 of the object light L2 in the plane of the entrance pupil plane of the objective lens 17. It is to let. When a prism is used as the second shift means 16, in the arrangement shown in FIG. 5, it is arranged on the optical path of the object light L2 traveling in the second direction, and shifts the incident object light L2 in parallel to the first direction. And is emitted. When it is sufficient to reproduce only the reproduction illumination light 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 plane is fixed. May be constant, and the same object light may always be emitted. However, in order to make it possible to manufacture a multifunctional illumination HOE, a second displacement amount changing means (second driving means) 22 is provided to change the position of the point P2 on the entrance pupil plane of the objective lens. Is preferred. 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 unit 22. According to this structure, it is possible to manufacture an illumination HOE capable of generating a plurality of reproduction irradiation lights by incident lights from different directions. Further, the second displacement amount changing means 22 also rotates the second prism 16 about the X axis similarly to the first displacement amount changing means 21 to shift the point P2 also in the Y axis direction in FIG. It is preferable to be configured to be shiftable. That is, it is preferable to freely configure the position of the point P2 on the entrance pupil plane of the objective lens in the XY directions. With this configuration, it is possible to manufacture an illumination HOE that can generate a plurality of reproduction irradiation lights in different directions by a plurality of incident lights from different directions.

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

  The immersion objective 17 includes 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 plane 20 and irradiates it toward the focal point O as parallel light having a predetermined angle φ1. Similarly, the liquid immersion objective lens 17 refracts the object light L2 from the point light source P2 on the entrance pupil plane 20 and irradiates it toward the focal point O as parallel light having a predetermined angle φ2. Note that, 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 anti-reflection means 23 is a member disposed between the photosensitive material 50 and the mounting table 24 holding the photosensitive material 50. The reference light L1 and the object light L2 passing through the photosensitive material 50 are reflected, and This is a means for preventing the material 50 from moving toward the material 50. The anti-reflection means 23 is preferably configured by a moth-eye structure member. The moth-eye structure is a structure having many nanometer-sized minute projections, and has a function of confining incident light so as not to reflect it. It is preferable to use the immersion liquid 26 also between the photosensitive material 50 and the moth-eye structure member. 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 at the critical angle on the surface of the photosensitive material and going to the photosensitive material 50 again. In addition, as a simple anti-reflection means, a black sheet absorbing light may be used. At that time, it is preferable to use the immersion liquid 26 between the black sheet absorbing the light and the photosensitive material 50.

  The mounting table 24 holds the photosensitive material 50 (and the anti-reflection means 23), and can be moved in the XYZ directions by the control means 25 so that the recording target portion of the photosensitive material 50 is adjusted to the focal point O of the immersion objective lens 17. Be composed.

[Method of manufacturing HOE for lighting]
When manufacturing the illumination HOE, the laser light L emitted from the laser light source 11 is separated via the beam splitter 14.

  One of the separated laser lights L1 becomes reference light (or object light), travels in the first direction (Z direction), shifts in parallel to the X-axis direction via the first prism 15, and emits a beam. The light passes through the splitter 14 and is focused on the entrance pupil plane 20 of the immersion objective 17 of the immersion objective 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 D1.

  The other separated laser light L2 becomes object light (or reference light), travels in the second direction (X direction), shifts in parallel to the Z-axis direction via the second prism 16, and becomes a beam. The light is reflected by the splitter 14 and focused on the entrance pupil plane 20 of the immersion objective 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 D2.

  The reference light L1 emitted from the point light source P1 is refracted by the liquid immersion objective lens 17, and the parallel light having a predetermined angle φ1 is irradiated toward the focal point O. The predetermined angle φ1 is an amount that depends on the amount of displacement D1. Further, the displacement amount D1 is determined by the shift amount ΔX of the first prism 15. For this reason, 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. It is preferable that φ1 includes an angle larger than the critical angle θc in relation to the critical angle θc of the light guide plate. Since refraction at the interface of the hologram recording medium is suppressed by the immersion liquid, it is preferable that 45 ° <φ1 <90 °.

  The object light L2 emitted from the point light source P2 is refracted by the immersion objective lens 17, and is irradiated with parallel light having a predetermined angle φ2 toward the focal point O. The predetermined angle φ2 is an amount dependent on the amount of displacement D2. Further, the displacement amount D2 is determined by the shift amount ΔZ of the second prism 16. Thus, 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. Note that the angle φ2 of the object light L2 is equal 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 correspond. φ2 is set in accordance with 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 °. As shown in FIG. 2, when the reproduction illumination light 32 emitted from the light guide plate 4 is refracted on the rear surface of the light guide plate 4 according to Snell's law to increase its angle, and is emitted at an emission angle θ4, the object light L2 Is set in consideration of refraction.

Here, in the manufacturing apparatus of the illumination HOE of the present invention, the immersion liquid 19 is used to fill the space between the objective lens body 18 and the photosensitive material 50 to be recorded by using the immersion objective lens 17. Thereby, 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 degree, and the angle of the reference light L1 is reduced. Precise control can be performed so that φ1 and the angle φ2 of the object light L2 become desired angles. 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 cross at the focal point O, the reference light L1 irradiated at an angle φ1 and the object light L2 irradiated at an angle φ2 onto the recording target portion of the photosensitive material 50 corresponding to the position of the focal point O Is formed, and an illumination hologram is recorded.

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

  As described above, in the present manufacturing apparatus and manufacturing method, by providing the distance between the reference light and the object light separated into two light fluxes (in other words, the displacement amount D1 + D2 or the distance from the point P1 to the point P2), the reference Light and object light can be applied to the photosensitive material at desired angles of incidence. Further, by appropriately moving the two prisms, the desired angle can be easily changed. In addition, the configuration of the immersion objective lens can reduce the error of the incident angle on the photosensitive material. Since the antireflection means having the moth-eye structure is employed, light passing through the photosensitive material is absorbed, and unnecessary reflection does not occur, which is preferable.

[Example]
FIG. 6 shows an embodiment 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 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 viewed from the thickness direction (Z direction) of the device.

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

  The glass plate 4 is 85 mm in height, 33 mm in width, and 12 mm in thickness. 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 illumination device of the present invention can be made sufficiently thin in comparison with the height × width of the device. . When a hologram illuminating device is manufactured by combining the configuration of the light source and the glass plate with another configuration (such as an HOE for illumination and holding means), the hologram illuminating device can realize a thickness of 13 to 18 mm. Note that the width of the device can be increased by increasing the number of LEDs.

  As described above, a plurality of embodiments have been described in this specification, but the scope of the present invention is not limited to each embodiment. For example, these plural forms can be combined.

DESCRIPTION OF SYMBOLS 1 Illumination device for hologram 2 Light source 4 Light guide plate 5 HOE for illumination
6 Hologram recording medium for image reproduction 7 Holding means 10 Hologram display device 30 Incident light 32 Reconstruction illumination light 34 Reproduction light 40 Parallelizing optical system 60 Stereoscopic image 100 Observer

Claims (7)

A light guide plate having a larger refractive index than air; and a light guide plate provided in contact with the light guide plate, receiving at least a part of light that propagates in the light guide plate and enters at an angle larger than a critical angle of the light guide plate with respect to air. A method for producing a hologram illumination device including an illumination holographic optical element that generates reproduction illumination light,
Arrange the photosensitive material of the holographic optical element for illumination so as to be located at the focal point of the high numerical aperture objective lens,
Separating the light from the light source into two light beams to generate reference light and object light,
The reference light is passed through the high numerical aperture objective lens such that the reference light passes through a first point separated by a first amount of displacement from a central axis of the high numerical aperture objective lens on an incident surface of the high numerical aperture objective lens. While irradiating the reference material refracted at a first angle corresponding to the first displacement amount to the photosensitive material, while being away from the central axis of the high numerical aperture objective lens by a second displacement amount. The object light is irradiated onto the high numerical aperture objective lens so as to pass through the second point, and the object light refracted at a second angle corresponding to the second displacement amount is applied to the photosensitive material. Irradiating and recording an illumination hologram to produce an illumination holographic optical element,
Arranging the illumination holographic optical element in which the illumination hologram is recorded in contact with the light guide plate,
The method according to claim 1, wherein the first angle or the second angle is larger than a critical angle of the light guide plate. It is provided in contact with a light guide plate having a larger refractive index than air, propagates through the light guide plate, receives at least a part of light incident at an angle larger than a critical angle of the light guide plate with respect to air, and generates reproduction illumination light. A method for producing a generated holographic optical element for illumination,
Arrange the photosensitive material of the holographic optical element for illumination so as to be located at the focal point of the high numerical aperture objective lens,
Separating the light from the light source into two light beams to generate reference light and object light,
The reference light is passed through the high numerical aperture objective lens such that the reference light passes through a first point that is separated from the central axis of the high numerical aperture objective lens by a first amount of displacement on an incident surface of the high numerical aperture objective lens. While irradiating the reference material refracted at a first angle corresponding to the first displacement amount to the photosensitive material, while being away from the central axis of the high numerical aperture objective lens by a second displacement amount. The object light is irradiated onto the high numerical aperture objective lens so as to pass through the second point, and the object light refracted at a second angle corresponding to the second displacement amount is applied to the photosensitive material. Irradiate,
The method of manufacturing a holographic optical element for illumination, wherein the first angle or the second angle is an angle larger than a critical angle of the light guide plate.   The method for manufacturing a hologram illumination device according to claim 1, wherein the high numerical aperture objective lens is an immersion objective lens, and is in contact with the photosensitive material via an immersion liquid. A method for producing a holographic optical element for illumination of the present invention.   The method according to claim 1 or 3, wherein the first displacement is changed by moving a first prism provided on an optical path of the reference light. A method for producing the holographic optical element for illumination according to claim 2.   5. The method according to claim 1, wherein an anti-reflection means having a moth-eye structure is disposed at a stage subsequent to the photosensitive material. Of producing a holographic optical element for use.   6. The hologram according to claim 1, wherein the first displacement or the second displacement is changed to record a plurality of holograms having different angle selectivity at the same position on the photosensitive material. The method of manufacturing the hologram illumination device according to any one of claims 1 to 6, or the method of manufacturing the holographic optical element for illumination according to any one of claims 2 to 5.   As the reference light, the photosensitive material is irradiated with the parallel light at the first angle, and as the object light, the photosensitive material is irradiated with the parallel light at the second angle. The method of manufacturing a hologram illumination device according to any one of claims 1 to 3, or the method of manufacturing a holographic optical element for illumination according to any one of claims 2 to 6.