JP2009145620A - Bonded optical element, method for manufacturing bonded optical element, image display device, and head mount display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bonded optical element having a fewer number of components, which reduces the number of process steps and prevents degradation of a hologram, and to provide an image display device including the bonded optical element, and a head mount display equipped with the image display device. <P>SOLUTION: An adhesive layer 23b bonding an ocular prism 21 and a deflection prism 22 of the bonded optical element is configured to record a hologram 24 by incorporating a base polymer, a polymerization initiator, a polymerizable monomer and a sensitized dye into the layer. By recording the hologram 24 in the adhesive layer 23b, the number of components of the bonded optical element is decreased, which decreases the number of process steps and prevents degradation in characteristics of the hologram 24 caused by permeation of the adhesive layer or shrinkage accompanying curing of the adhesive layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a bonded optical element obtained by bonding two adjacent transparent optical members with an adhesive layer, a method for manufacturing the bonded optical element, a video display apparatus including the bonded optical element, and a video display apparatus. The head-mounted display.

Bonded optical elements that are used by embedding a hologram in a transparent substrate are very suitable for head-up displays and head-mounted displays as optical elements that are not affected by the external environment such as humidity and oxygen by embedding the hologram in the transparent substrate. Useful. Such a bonded optical element is disclosed in Patent Document 1, for example.
JP-A-7-234627

  Therefore, a conventional bonded optical element as disclosed in Patent Document 1 will be described with reference to FIG.

  As shown in FIG. 11A, the hologram recording material 102 is disposed on the bonding surface 101a where the transparent substrate 101 is bonded to the transparent substrate 104 (see FIG. 11D). At this time, for example, a sheet-like photopolymer is used for the hologram recording material 102. Then, as shown in FIG. 11B, the hologram recording material 102 is irradiated with two coherent laser beams from both sides, thereby producing a hologram layer 103 on which a hologram is recorded with interference fringes. The produced hologram layer 103 is fixed by irradiating with ultraviolet rays as shown in FIG. Thereafter, as shown in FIG. 11D, an adhesive material 105 is applied to the bonding surface 101a including the hologram layer 103 of the transparent substrate 101 to bond the transparent substrate 101 and the transparent substrate 104 together. Finally, as shown in FIG. 11E, the bonded optical element 100 is manufactured by curing the adhesive material 105 by a polymerization reaction by irradiating ultraviolet rays.

  However, the conventional bonding optical element 100 requires two materials, namely, a hologram recording material 102 for recording a hologram and an adhesive material 105 for bonding the transparent substrates, and has a large number of components and a large number of components. The increase causes a problem that the number of processes increases. In order to dispose the adhesive material 105 on the hologram layer 103, the adhesive material 105 penetrates into the hologram layer 103 or contracts when the adhesive material 105 is cured, so that the characteristics of the hologram layer 103 deteriorate. The problem of doing so has arisen.

  The present invention has been made to solve the above-described problems, and its purpose is to reduce the number of parts, to shorten the number of steps, and to further prevent deterioration of hologram characteristics. To provide a bonded optical element, a method for manufacturing the bonded optical element, an image display device including the bonded optical element, and a head-mounted display including the image display device.

  In order to achieve the above object, the present invention comprises a plurality of transparent optical members and an adhesive layer that joins two adjacent transparent optical members, and a hologram is recorded in the adhesive layer. It is characterized by.

  According to the above configuration, the bonded optical element of the present invention has a hologram recorded in the adhesive layer. Conventionally, a bonded optical element is constituted by two layers of a hologram layer on which a hologram is recorded and an adhesive layer that bonds two transparent optical members. However, in the present invention, since a hologram is recorded in the adhesive layer, a bonded optical element having hologram characteristics can be formed by one layer of the adhesive layer. Therefore, the number of parts of the bonded optical element can be reduced. And since the number of parts can be reduced, the manufacturing process of a joining optical element can be shortened. In addition, since the hologram layer and the adhesive layer are conventionally formed as separate layers, the characteristics of the hologram deteriorate due to penetration of the adhesive layer into the hologram layer, shrinkage when the adhesive layer is cured, or the like. It was. However, in the present invention, since the hologram and the adhesive layer are the same layer, the deterioration of the characteristics of the hologram due to penetration or shrinkage of the adhesive layer does not occur.

  In the bonded optical element having the above structure according to the present invention, it is preferable that the adhesive layer includes a polymerization initiator, a polymerizable monomer, a base polymer, and a sensitizing dye.

  According to the said structure, the adhesive bond layer of this invention is comprised by containing a polymerization initiator, a polymerizable monomer, and a sensitizing dye in the base polymer (matrix polymer) which is a high molecular compound. The principle of recording the hologram by the adhesive layer in the present invention will be described below. The hologram is recorded by the difference in refractive index between the bright and dark portions of the interference fringes generated by causing the two light beams to interfere. Therefore, when two coherent light beams are irradiated to the adhesive layer of the present invention, the sensitizing dye located in the bright part of the interference fringe absorbs the energy of the light beam and gives the polymerization initiator energy, thereby causing the polymerization reaction. Start. When the polymerization reaction is started, the polymerizable monomer diffuses from the dark part of the interference fringe to the bright part of the interference fringe, and polymerization is continuously performed. Finally, a bright part of interference fringes composed of a polymerizable monomer and a base polymer and a dark part of interference fringes composed of a base polymer are formed. Here, since the difference in refractive index between the bright part of the interference fringe and the dark part of the interference fringe becomes large, a hologram can be recorded.

  In the bonded optical element having the above structure according to the present invention, the polymerizable monomer preferably includes N-vinylcarbazole.

  According to the above configuration, in order to produce a hologram having high diffraction efficiency, it is necessary to increase the refractive index difference between the bright part and the dark part. Therefore, in the bonded optical element of the present invention, the polymerizable monomer contains N-vinylcarbazole which is a material having a high refractive index, thereby further widening the refractive index difference between the bright part of the interference fringe and the dark part of the interference fringe. And a hologram with high diffraction efficiency can be produced.

  In the bonded optical element having the above-described configuration, the sensitizing dye preferably includes one or more kinds of dyes and absorbs light in the red, green, and blue wavelength regions.

  According to the above configuration, a hologram that can be reproduced in color is produced by configuring the sensitizing dye with a dye that absorbs light in the red (R), green (G), and blue (B) wavelength regions. be able to. In this case, the sensitizing dye may be composed of three kinds of dyes that absorb light in the RGB wavelength range, for example, a dye that absorbs light in the RG wavelength range and light in the B wavelength range. You may be comprised with two types of pigment | dye to absorb. Alternatively, one type of dye that absorbs light in the RGB wavelength range may be used.

  Further, in the bonded optical element having the above-described configuration, the present invention is configured such that the two adjacent transparent optical members and the adhesive layer that bonds the transparent optical members are made of an acrylic or cycloolefin-based material. It is preferable that

  According to the above configuration, if the transparent optical member and the adhesive layer are configured using the same series of materials such as an acrylic material or a cycloolefin material, the mutual adhesion is increased and a high bonding force is obtained. Can do. These effects can be reliably obtained if the main component (for example, 70% by weight or more) of the transparent optical member and the adhesive layer is an acrylic material or a cycloolefin material.

Further, in the cemented optical element having the above-described configuration, the present invention may be configured such that the refractive index of the bright part of the interference fringe is n1 and the refractive index of the dark part of the interference fringe is n2.
0.01 ≦ | n1-n2 | ≦ 0.05 (1)
It is preferable to satisfy.

  According to the said structure, the high diffraction efficiency and half value width which can be used as a hologram can be obtained by satisfy | filling conditional expression (1).

In the bonded optical element having the above-described configuration, the adhesive layer may have a thickness of t μm.
10 ≦ t ≦ 300 (2)
It is preferable to satisfy.

  According to the said structure, the high diffraction efficiency and half value width which can be used as a hologram can be obtained by satisfying conditional expression (2).

  In order to achieve the above object, the present invention provides a first step of disposing an uncured adhesive layer between two transparent optical members, and a coherent two-beam laser beam that is coherent with the adhesive layer. The interference fringes are recorded as a hologram in a partial region of the adhesive layer, and at the same time, the two transparent optical members are joined by curing the adhesive layer by a polymerization reaction during recording of the hologram. And 2 processes.

  According to the above configuration, by irradiating the adhesive layer with two coherent laser beams, simultaneously with recording of the hologram, the adhesive layer is cured by a polymerization reaction at the time of recording the hologram. Join the members. Therefore, the process of recording a hologram, which has been performed as a separate process in the conventional manufacturing method, and the process of bonding two transparent optical members can be performed in one process in the manufacturing method of the present invention. As a result, the manufacturing process can be shortened. Further, since the hologram is recorded on the adhesive layer, a separate hologram material is not required, and it can be manufactured with a small number of parts. Since the bonding process and the hologram recording process are performed simultaneously, it is possible to suppress the deterioration of the hologram characteristics.

  In the method for manufacturing a bonded optical element having the above-described configuration, the sensitizing dye contained in the adhesive layer is decomposed by irradiating the entire surface of the adhesive layer with ultraviolet rays after the second step. At the same time, it is preferable to include a third step of polymerizing and curing the monomer in the hologram non-recorded area to join the two transparent optical members.

  According to the above configuration, at the same time that the hologram is recorded on the adhesive layer and at the same time the two transparent optical members are joined by the adhesive layer, the hologram recording area cured by the polymerization reaction and unpolymerized remain. Uncured hologram unrecorded areas are mixed in the adhesive layer. In addition, the sensitizing dye contained in the adhesive layer for recording the hologram absorbs the light flux after recording the hologram, and further causes a polymerization reaction to cause the adhesive layer to contract. Wake up. Thus, after the second step, the entire surface of the adhesive layer is irradiated with ultraviolet rays to decompose the sensitizing dye, thereby fixing the adhesive layer and having a stable structure, and no absorption of the sensitizing dye. A bonded optical element having high transparency can be manufactured. Simultaneously with the decomposition of the sensitizing dye, the monomer in the hologram unrecorded area is polymerized and cured, so that it is not necessary to provide a separate process for curing the hologram unrecorded area by light irradiation. can do.

  In the method for manufacturing a bonded optical element having the above-described configuration, the hologram unrecorded area of the adhesive layer is irradiated with one beam of laser light or two beams of incoherent laser light, and polymerization is performed. It is preferable to join the two transparent optical members by reaction.

  According to the above configuration, for example, by arranging a light-shielding plate at a predetermined position in the hologram non-recorded area of the adhesive layer, one of the two light beams is blocked and the other laser light is irradiated, or For example, by arranging a wave plate at a predetermined position and changing the polarization direction of one laser beam so as to be orthogonal to the other, irradiation with two light beams of incoherent laser light causes interference fringes. Without curing, curing by a polymerization reaction is performed, and the two transparent optical members are joined. Thereby, since no interference fringes are generated in the hologram non-recorded area, the hologram is not recorded. Therefore, it is possible to suppress the occurrence of ghosts due to the generation of unnecessary interference fringes in areas other than the hologram recording area. Further, since no interference fringes are generated in the hologram non-recorded area, a large refractive index difference does not occur in the minute area of the adhesive layer, so that the adhesive layer can be uniformly cured.

  In the method for manufacturing a bonded optical element according to the present invention, it is preferable that the laser irradiation of the hologram layer unrecorded area of the adhesive layer is performed simultaneously with the hologram recording by the laser irradiation.

  According to the above configuration, the bonded optical element is easily manufactured as compared with the case where the step of curing the hologram non-recorded region by laser irradiation is performed with a time shift from the time of recording the hologram (compared to the case where it is provided as a separate step) be able to.

  According to the present invention, in the method for manufacturing a bonded optical element having the above-described configuration, before the hologram is recorded in a partial region of the adhesive layer by laser irradiation, the region other than the hologram of the adhesive layer is recorded. Thus, it is preferable to irradiate the polymerization initiation light for joining the two transparent optical members by a polymerization reaction.

  According to the above configuration, since the two transparent optical members are joined and integrated in advance before hologram recording, the occurrence of misalignment and the like can be prevented, and workability becomes easy. As the polymerization initiating light, laser light, ultraviolet light, visible light, or the like used for recording a hologram can be used.

  Moreover, the bonded optical element of the present invention may be manufactured by the above-described manufacturing method of the present invention.

  In the cemented optical element having the above structure according to the present invention, it is preferable that the hologram is a volume phase reflection type hologram.

  According to the above configuration, the reflection type volume phase hologram has high wavelength selectivity, and the full width at half maximum of the peak of diffraction efficiency is narrow. Therefore, for example, it can be used as a combiner that guides image light and external light simultaneously to the eyes of the observer. Further, when a hologram is used as such a combiner, the external light transmittance is increased, and the external image can be clearly observed.

  In order to achieve the above object, the present invention comprises an illumination light source, a video display element that modulates light from the light source to display an image, and the above-described bonding optical element, The image light is incident from the incident surface of the bonding optical element, is internally totally reflected a plurality of times and guided to the hologram of the bonding optical element, and the image light is magnified and reflected by the hologram to be the exit surface of the bonding optical element. The light is emitted to the outside and guided to the observer's eye as a virtual image, and at the same time, the light of the external image transmitted through the hologram is guided to the observer's eye.

  According to the above configuration, the light emitted from the light source is modulated by the video display device and emitted as video light. The image light is incident from the incident surface of the transparent optical member, totally reflected a plurality of times inside, then reflected by the hologram and emitted from the emission surface. Thereby, the observer can observe the video as an enlarged virtual image. Further, since the light of the external image transmitted through the hologram is guided to the eyes of the observer, the observer can observe the virtual image and the external image simultaneously. Thus, by constructing the apparatus using the cemented optical element of the present invention, since the hologram also serves as an eyepiece optical system, the apparatus can be reduced in size and weight. In addition, a bright image can be provided to the observer by combining the light emission wavelength of the light source and the diffraction wavelength of the hologram. Furthermore, since the configuration uses total reflection in the transparent optical member, the transparent optical member can be reduced in size and weight, the light transmittance of the external image can be increased, and the external image can be observed well. Further, by joining adjacent transparent optical members, it is possible to prevent external light from being refracted by one of the transparent optical members and to observe the external image satisfactorily. And it becomes possible to arrange | position an image display element to the periphery of a visual field, and can ensure a wide external field viewing angle.

  Further, the present invention is the image display device having the above-described configuration, wherein the hologram has a positive non-axisymmetric optical power for enlarging the image displayed on the image display element, and the display image is viewed by an observer. It is preferable that at least a part of an eyepiece optical system that guides the eye as a virtual image is formed.

  In this case, the eyepiece optical system can be reduced in size, and an image with good aberration correction can be observed.

  In order to achieve the above object, the present invention includes the video display device according to claim 15 or claim 16 and a support member that supports the video display device in front of an observer's eyes. It is said.

  According to the above configuration, since the video display device is instructed by the support means in front of the observer's eyes, the observer becomes hands-free and has a free hand while observing the external image and the display image on the video display element as a virtual image. The desired work can be performed. In addition, since the observation direction of the observer is determined in one direction, there is an advantage that the observer can easily search for a display image even in a dark environment.

  According to the present invention, since the hologram is recorded in the adhesive layer that joins two adjacent transparent optical members, there is no need to provide a material for recording the hologram separately, and the number of parts of the joining optical element is reduced. be able to. Further, as the number of parts decreases, the manufacturing process of the bonded optical element can be shortened. Since the hologram is recorded in the adhesive layer, it is possible to prevent the deterioration of the characteristics of the hologram layer due to the penetration of the adhesive layer and the shrinkage accompanying the hardening of the adhesive layer.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
(About head mounted display)
2A is a plan view showing a schematic configuration of the head mounted display in the present embodiment, FIG. 2B is a side view of the head mounted display, and FIG. 2C is a head mounted display. It is a front view of a display. The head mounted display 1 includes an image display device 2 and a support means 3 that supports the image display device 2. As a whole, the head mounted display 1 has an appearance in which one lens (for example, for the left eye) is removed from general glasses. It has become.

  The video display device 2 allows an observer to observe an outside world image with see-through, displays an image, and provides it to the observer as a virtual image. In the video display device 2 shown in FIG. 2C, the portion corresponding to the right eye lens of the spectacles is configured by bonding an eyepiece prism 21 and a deflection prism 22 (see FIG. 3) described later. The detailed configuration of the video display device 2 will be described later.

  The support means 3 supports the video display device 2 in front of the observer's eyes (for example, in front of the right eye), and includes a bridge 4, a frame 5, a temple 6, a nose pad 7, and a cable 8. ing. The frame 5, the temple 6 and the nose pad 7 are integrally provided on the left and right sides. However, when these are distinguished from each other on the left and right, the right frame 5R, the left frame 5L, the right temple 6R, the left temple 6L, the right nose pad It shall be expressed as 7R, left nose pad 7L.

  One end of the video display device 2 is supported by the bridge 4. The bridge 4 supports the left frame 5 </ b> L and the nose pad 7 in addition to the video display device 2. The left frame 5L supports the left temple 6L so as to be rotatable. On the other hand, the other end of the video display device 2 is supported by the right frame 5R. In the right frame 5R, the side end located opposite to the support side of the video display device 2 supports the right temple 6R in a rotatable manner. The cable 8 is a wiring for supplying an external signal (for example, a video signal, a control signal) and power to the video display device 2, and is provided along the right frame 5R and the right temple 6R.

  When the observer uses the head-mounted display 1, the right temple 6R and the left temple 6L are brought into contact with the right and left heads of the observer, and the nose pad 7 is placed on the nose of the observer, so that general glasses are used. The head mounted display 1 is attached to the observer's head so that When an image is displayed on the image display device 2 in this state, the observer can observe the image on the image display device 2 as a virtual image, and observes the outside image through the image display device 2 in a see-through manner. be able to.

  In the head mounted display 1 having the above-described configuration, the video display device 2 is instructed by the support means 3 in front of the viewer's eyes. While observing, it is possible to perform a desired operation with a free hand. In addition, since the observation direction of the observer is determined in one direction, there is an advantage that the observer can easily search for a display image even in a dark environment.

The head mounted display 1 shown in FIGS. 2A, 2B, and 2C has a configuration including only one video display device 2, but the video display device 2 is provided corresponding to the left and right eyes. Of course, it is possible to have a configuration with two.
(About video display device)
Next, details of the above-described video display device will be described.

  FIG. 3 is a cross-sectional view illustrating a schematic configuration of the video display device. The video display device 2 a includes a light source (illumination light source) 11, a video display element 12, and a cemented optical element (eyepiece optical system) 20. The video display element 12 includes a unidirectional diffusion plate 13, a condenser lens 14, and an LCD 15.

  The light source 11 is composed of an RGB-integrated LED that emits light in three wavelength bands whose center wavelengths are, for example, 465 nm, 520 nm, and 635 nm. The unidirectional diffuser plate 13 diffuses the illumination light from the light source 11, but the degree of diffusion differs depending on the direction. More specifically, the unidirectional diffuser plate 13 diffuses incident light by about 40 ° in a direction corresponding to the left and right direction when the head mounted display is worn by the observer (direction perpendicular to the paper surface of FIG. 3). The incident light is diffused by about 0.2 ° in the vertical direction (direction parallel to the paper surface of FIG. 3) when the observer mounts the head mounted display. The condensing lens 14 condenses the light diffused by the unidirectional diffusion plate 13. The condenser lens 14 is disposed so that the diffused light efficiently forms the optical pupil E.

  The LCD 15 is a light modulation element that displays an image by modulating light from the light source 11 based on the image signal. In this embodiment, the LCD 15 is a transmissive type, but may be a reflective type. In this case, it is necessary to devise the arrangement position of other optical elements such as the light source 11. Further, a light modulation element other than the LCD 15 (for example, DMD (Digital Micromirror Device; manufactured by Texas Instruments, USA)) may be used.

  On the other hand, the cemented optical element 20 includes an eyepiece prism 21, a deflection prism 22, and an adhesive layer 23 that joins the eyepiece prism 21 and the deflection prism 22. The eyepiece prism 21 and the deflecting prism 22 are joined so that a continuous surface shape is formed at the joint.

  The eyepiece prism 21 and the deflection prism 22 are made of, for example, an acrylic resin (described later). The eyepiece prism 21 is formed in a shape in which a lower end portion of a parallel plate is wedge-shaped and an upper end portion thereof is thickened, and has surfaces 21a, 21b, and 21c. The surface 21a is an incident surface on which the image light from the image display element 12 is incident, and the surfaces 21b and 21c are surfaces facing each other. Among these, the surface 21b is a total reflection surface and an emission surface.

  The deflection prism 22 is configured to be a substantially parallel flat plate integrated with the eyepiece prism 21 by forming the upper end portion of the parallel plate along the lower end portion of the eyepiece prism 21. When the deflecting prism 22 is not joined to the eyepiece prism 21, the external image light is refracted when passing through the wedge-shaped lower end portion of the eyepiece prism 21, so that the external field image observed through the eyepiece prism 21 is distorted. However, the deflecting prism 22 is joined to the eyepiece prism 21 to form an integral substantially parallel plate, so that the refraction when the light of the external image is transmitted through the wedge-shaped lower end of the eyepiece prism 21 is canceled by the deflecting prism 22. can do. As a result, it is possible to prevent distortion in the external image observed through the see-through.

  The adhesive layer 23 joins the eyepiece prism 21 and the deflecting prism 22 and diffracts light of three wavelength bands, for example, 465 nm ± 10 nm, 520 nm ± 10 nm, and 635 nm ± 10 nm, which are incident at a specific incident angle. A phase hologram 24 (see FIG. 1B) is recorded. This configuration will be described later.

  The light emitted from the light source 11 by the configuration of the video display device 2a is diffused by the one-way diffusion plate 13, condensed by the condenser lens 14, and incident on the LCD 15. The light incident on the LCD 15 is modulated based on the video signal and emitted as video light. At this time, the image itself is displayed on the LCD 15.

  The image light from the LCD 15 is incident on the inside of the eyepiece prism 21 from the upper end (surface 21a) of the eyepiece prism 21 of the cemented optical element 20, and is totally reflected a plurality of times by the two opposite surfaces 21b and 21c. Incident on the layer 23. The light incident on the adhesive layer 23 is reflected there and emitted through the surface 21b and reaches the optical pupil E. At the position of the optical pupil E, the observer can observe an enlarged virtual image of the image displayed on the LCD 15. The distance from the optical pupil E to the virtual image is about several meters, and the size of the virtual image is 10 times or more that of the image displayed on the LCD 15.

  On the other hand, the eyepiece prism 21, the deflecting prism 22, and the adhesive layer 23 transmit almost all the light from the outside, so that the observer can observe the outside world image. Therefore, the virtual image of the image displayed on the LCD 15 is observed while overlapping with a part of the external image.

  As described above, in the video display device 2a, the video light emitted from the LCD 15 is guided to the optical pupil E by total reflection in the eyepiece prism 21, so that the eyepiece prism 21 and the deflector are deflected in the same manner as a normal spectacle lens. The thickness of the prism 22 can be set to about 3 mm, and the bonded optical element 20 and thus the video display device 2a can be reduced in size and weight. Further, the light transmittance of the external image becomes high, and the external image can be observed well. Furthermore, the video display element 12 can be arranged at a position far away from immediately before the eyes of the observer, and a wide field of view for the outside world of the observer can be secured. In addition, since the hologram 24 is recorded in the adhesive layer 23, a bright image can be provided to the observer by combining the diffraction wavelength of the light source 11 and the diffraction wavelength of the hologram 24.

  The hologram 24 recorded in the adhesive layer 23 is composed of a volume phase type reflection hologram that diffracts only light of a specific wavelength at a specific incident angle as described above. The light does not affect the light of the external image that passes through the eyepiece prism 21, the deflecting prism 22, and the adhesive layer 23. In other words, volume phase type reflection holograms are both highly wavelength selective and angle selective, and therefore have a diffractive reflection effect only on light in a limited wavelength range. And a combiner that synthesizes transmitted light of other wavelengths. Therefore, an observer observes a virtual image of the display image of the LCD 15 through the hologram 24 and observes the outside world image clearly and normally through the eyepiece prism 21, the deflection prism 22 and the adhesive layer 23. Can do.

  The hologram 24 recorded on the adhesive layer 23 has a positive non-axisymmetric optical power for enlarging the image displayed on the LCD 15, and guides the display image to the observer's eye as a virtual image. Since at least a part of the cemented optical element 20 is configured, the cemented optical element 20 can be reduced in size, and an image that has been favorably corrected for aberrations can be provided to an observer.

  Since the hologram 24 is recorded in the adhesive layer 23 at the joint between the eyepiece prism 21 and the deflection prism 22, the hologram 24 can be prevented from being affected by the external environment, and stable performance can be achieved. Can keep.

(About bonded optical elements)
Next, details of the above-described bonded optical element will be described.

  The cemented optical element 20 includes an eyepiece prism 21 and a deflecting prism 22 as a plurality of transparent optical members, and an adhesive layer 23 that joins the eyepiece prism 21 and the deflecting prism 22 and records a hologram 24. . FIG. 4A shows a plan view of the eyepiece prism, and FIG. 4B shows a side view of the eyepiece prism. FIG. 5A shows a plan view of the deflection prism, and FIG. 5B shows a side view of the deflection prism. FIG. 6 is a plan view of the bonded optical element of the present invention.

  The eyepiece prism 21 has a substantially quadrangular pyramid shape as a whole, and its upper surface and lower surface are connected by four side surfaces. These four side surfaces are constituted by surfaces 21d, 21e, 21f, and 21g arranged counterclockwise with the upper surface as the center in FIG. 4A. These surfaces 21d, 21e, 21f, and 21g have different normal directions. The surface 21d is formed with a protruding portion that protrudes upward from the upper surface.

  As shown in FIG. 5A, the deflection prism 22 has a shape such that a parallel plate is formed by joining the eyepiece prism 21. That is, the deflection prism 22 has a shape obtained by hollowing out the shape of the eyepiece prism 21 from a parallel plate. Here, in the deflecting prism 22, when the eyepiece prism 21 is joined, surfaces facing the surfaces 21e, 21f, and 21g of the eyepiece prism 21 are surfaces 22a, 22b, and 22c, respectively. The normal directions of these surfaces 22a, 22b, and 22c are also different from each other.

  The adhesive layer 23 is disposed between the surfaces 21e, 21f, and 21g of the eyepiece prism 21 and the surfaces 22a, 22b, and 22c of the deflection prism 22, and joins the eyepiece prism 21 and the deflection prism 22 with the three surfaces. As shown in FIG. 6, the adhesive layer 23 has adhesive layers 23a, 23b, and 23c that join the surfaces 21e, 21f, and 21g of the eyepiece prism 21 and the surfaces 22a, 22b, and 22c of the deflection prism 22. ing. Then, in the adhesive layer 23b that joins the surface 21f of the eyepiece prism 21 and the surface 22b of the deflection prism 22 shown in FIG. 4B or 5B, the hologram 24 ( (See FIG. 6). Therefore, the principle of bonding with the adhesive layer and the principle of recording the hologram will be described below.

  The adhesive layer 23 is configured by including a polymerization initiator, a polymerizable monomer, and a sensitizing dye in a base polymer (matrix polymer) that is composed of a high molecular compound and has a function of maintaining a low molecule. . For this reason, when the light is absorbed by the polymerization initiator by irradiating light, the polymerization reaction is started, and the polymerization reaction is continuously performed by the polymerizable monomer. And the adhesive bond layer 23 can function as an adhesive agent by the hardening accompanying a polymerization reaction.

  On the other hand, the hologram 24 is recorded by the difference in refractive index between the bright part and the dark part of the interference fringes generated by causing the two light beams to interfere. Therefore, when two coherent light beams are irradiated to a part of the adhesive layer 23b, the sensitizing dye located in the bright part of the interference fringe absorbs the energy of the light beam and gives the polymerization initiator energy. The polymerization reaction starts. When the polymerization reaction is started, the polymerizable monomer diffuses from the dark part of the interference fringe to the bright part of the interference fringe, and polymerization is continuously performed. Finally, a bright part of interference fringes mainly composed of a polymerizable monomer and a base polymer and a dark part of interference fringes mainly composed of a base polymer are formed. Here, by adding a sensitizing dye having a wavelength characteristic for absorbing the laser light irradiated during recording of the hologram 24, the polymerizable monomer can be cured in accordance with the shading of the interference fringes. Since the difference in refractive index between the bright part of the interference fringe and the dark part of the interference fringe becomes large, the hologram 24 can be recorded. If a plasticizer is further added, the diffusion of the polymerizable monomer becomes easier and it becomes easy to have a large refractive index difference.

  In this way, the surface 21f of the eyepiece prism 21 and the surface 22b of the deflecting prism 22 can be joined by curing accompanying the polymerization reaction when recording the hologram 24, so that the adhesive layer 23b records the hologram 24. The eyepiece prism 21 and the deflecting prism 22 can be joined at the same time.

  Further, in order to record the hologram 24 having high diffraction efficiency, it is preferable to use a plurality of types of polymerizable monomers at the same time in consideration of polymerizability, refractive index, curing characteristics, and the like. Among them, it is very good to use N-vinylcarbazole as one of the polymerizable monomers. N-vinyl carbazole is a typical highly refractive polymerizable monomer, and effectively works to increase the difference in refractive index between the bright part and the dark part.

  The sensitizing dye is composed of one or more kinds of dyes, and absorbs light in the red (R), green (G), and blue (B) wavelength regions. By including a dye that absorbs light in the RGB three-color wavelength range as a sensitizing dye that absorbs laser light, it is possible to record a hologram 24 that can be reproduced in color using RGB three-wavelength laser light. As the sensitizing dye, one type of dye that absorbs light in the RGB wavelength range may be used. For example, a dye that absorbs light in the R wavelength range and light in the G and B wavelength ranges are absorbed. You may use two types of pigment | dyes with a pigment | dye. Alternatively, three types of dyes that absorb light in each of the RGB wavelength ranges may be used.

  As will be described later, the sensitizing dye is desirably decomposed by the hologram fixing step so that unnecessary interference fringes are not recorded after hologram recording, and desirably has a property of being decomposed by light or heat. . Examples of such dyes include cyanine dyes and squarylium dyes that absorb light in the R wavelength region, and examples of dyes that absorb light in the G wavelength region and B wavelength region. And coumarin dyes.

In the hologram 24 recorded with the above-described configuration, the bright part of the interference fringe is n1, and the dark part of the interference fringe is n2.
0.01 ≦ | n1-n2 | ≦ 0.05 (1)
Is satisfied.
Further, when the thickness of the adhesive layer 23 having the recorded hologram 24 is t (μm), the thickness of the adhesive layer 23 is
10 ≦ t ≦ 300 (2)
Is satisfied.

  The characteristics of the hologram 24 depend on the refractive index difference and film thickness parameters. The diffraction efficiency of the hologram increases as the refractive index difference increases. Also, the thicker the film, the higher the diffraction efficiency. However, if the film thickness is increased more than necessary, the full width at half maximum wavelength of the diffraction efficiency becomes narrow, so that the amount of light incident on the optical pupil decreases and the brightness becomes dark. On the other hand, if the full width at half maximum wavelength is increased in order to increase the luminance, light in many wavelength ranges is diffracted, so that the wavelength selectivity of the hologram 24 is deteriorated, and external light that is observed through the hologram 24 is observed. Becomes darker. Therefore, by configuring the hologram 24 so as to satisfy the conditional expressions (1) and (2) described above, the hologram 24 recorded in the adhesive layer 23 can be used as the hologram 24 at the full width at half maximum wavelength of diffraction efficiency or It can have diffraction efficiency. In particular, the refractive index difference of the hologram 24 is preferably about 0.02 ≦ | n1−n2 | ≦ 0.05, and the thickness t of the adhesive layer 23 is preferably 20 μm ≦ t ≦ 100 μm.

  The eyepiece prism 21 and the deflecting prism 22 which are transparent optical members include, for example, acrylic resins such as PMMA (polymethyl methacrylate) and MMA (methyl methacrylate), ZEONEX (registered trademark), and Apel (registered trademark). It is comprised using cycloolefin type resins, such as. Since these organic materials have high transparency and low birefringence, good optical characteristics (for example, transmission characteristics) can be obtained when a transparent optical member is formed. The adhesive layer 23 is made of an acrylic resin or a cycloolefin resin. For example, an acrylic polymerizable monomer constituting the adhesive layer 23 is an acrylate derivative (2-phenoxyethyl). Acrylate, vinyl acetate and the like), and examples of the matrix polymer include polymethyl methacrylate (PMMA) and a copolymer thereof, and polyvinyl acetate. As described above, the eyepiece prism 21, the deflecting prism 22, and the adhesive layer 23 are made of the same acrylic material or the same series of organic materials such as cycloolefin materials, so that the adhesion is improved and a high bonding force is obtained. Obtainable. These effects can be reliably obtained if the main component (for example, 70% by weight or more) of the eyepiece prism 21, the deflection prism 22, and the adhesive layer 23 is an acrylic material or a cycloolefin material. be able to.

  The cycloolefin-based material is a material that improves the heat resistance of the acrylic-based material, and its properties are very similar. For example, a cycloolefin-based material is used for the transparent optical member to form the adhesive layer 23. Even when an acrylic material is used, the above-described effects can be obtained.

  With the above configuration, the adhesive layer 23 can record the hologram 24 on a part of the adhesive layer 23 at the same time as the eyepiece prism 21 and the deflecting prism 22 are joined. For this reason, since the bonded optical element 20 can be configured without using two kinds of materials, ie, a hologram recording material and an adhesive material, as in the prior art, the number of parts of the bonded optical element 20 can be reduced. And since the number of parts can be reduced, the manufacturing process of the joining optical element 20 can be shortened. Moreover, since the hologram 24 and the adhesive layer 23 are made of the same material, the deterioration of the hologram 24 due to the penetration and shrinkage of the adhesive layer 23 can be prevented.

(About manufacturing method of bonded optical element)
Next, the detail of the manufacturing method of the junction optical element mentioned above is demonstrated. 1A to 1C are cross-sectional views showing a method for manufacturing a bonded optical element of the present invention. For the sake of explanation, the cross-sectional view of the manufacturing method shown below is a cross-sectional view of the adhesive layer 23b that is bonded at the same time as recording a hologram. In the first manufacturing process shown in FIG. 1A, the eyepiece prism 21 and the deflecting prism 22 are arranged via an adhesive layer 23b.

  Next, as shown in FIG. 1B, after the first manufacturing process, a second manufacturing process is performed in which a part of the adhesive layer 23b is irradiated with a coherent two-beam laser beam. . In the present embodiment, in order to record a volume phase type reflection hologram on the adhesive layer 23b, two beams of laser light are irradiated from the eyepiece prism 21 side and the deflection prism 22 side. At this time, the light irradiated from the deflecting prism 22 side is irradiated to the adhesive layer 23b without being totally reflected by the deflecting prism 22 by using the light introducing prism 25 which is closely attached to the deflecting prism 22 with matching oil. Is done. By such irradiation of two light beams, interference fringes are produced in a part of the adhesive layer 23b, and the hologram 24 is recorded in accordance with the above-mentioned principle of hologram recording. The prism 22 is joined. An area of the adhesive layer 23b where the hologram 24 is recorded is referred to as a hologram recording area 28.

  At this time, by exposing the adhesive layer 23b using a laser light source that emits light in the RGB wavelength band, the hologram 24 that functions in correspondence with the three colors of RGB can be obtained. That is, the hologram 24 that diffracts and reflects RGB light can be recorded. Then, after the second manufacturing process, as shown in FIG. 1C, a third manufacturing process of irradiating the adhesive layer 23 including the hologram recording region 28 with ultraviolet rays is performed.

  As described above, in the method for manufacturing a bonded optical element of the present invention, when the hologram 24 is recorded simultaneously with the recording of the hologram 24 by irradiating the adhesive layer 23 with the coherent two-beam laser beam. The eyepiece prism 21 and the deflecting prism 22 are bonded together by curing the adhesive layer 23 by the polymerization reaction. Therefore, the process of recording a hologram, which has been performed as a separate process in the conventional manufacturing method, and the process of bonding two transparent optical members can be performed in one process in the manufacturing method of the present invention. As a result, the manufacturing process can be shortened. Further, since the hologram 24 is recorded on the adhesive layer 23, a separate hologram material is not required, and it can be manufactured with a small number of parts. Further, since the bonding process and the hologram recording process are performed simultaneously, it is possible to suppress the deterioration of the hologram 24.

  In addition, after the second manufacturing process, the adhesive recording layer 23 undergoes a polymerization reaction by irradiation with laser light for hologram recording, and the hologram recording area in which the eyepiece prism 21 and the deflection prism 22 are joined. 28 and a hologram unrecorded area 29 in which the eyepiece prism 21 and the deflecting prism 22 are not joined together are left unmixed. The hologram non-recorded area 29 also includes the hologram non-recorded area 29 in the adhesive layers 23a and 23c. Further, the sensitizing dye contained in the adhesive layer 23 absorbs the light flux after recording the hologram 24, and further causes a disadvantage such as causing a polymerization reaction to shrink the adhesive layer 23. Therefore, in the third step, the entire surface of the adhesive layer 23 is irradiated with ultraviolet rays to decompose the sensitizing dye, so that the adhesive layer 23 is fixed and has a stable structure, and the sensitizing dye is absorbed. It is possible to manufacture a bonded optical element 20 with high transparency. Further, simultaneously with the decomposition of the sensitizing dye, the monomer in the hologram unrecorded area 29 is polymerized and cured, so that it is not necessary to provide a process for curing the hologram unrecorded area 29 by light irradiation as a separate process. 20 can be manufactured.

  Further, in the method for manufacturing the bonded optical element 20 of the present invention, in addition to the method for manufacturing the bonded optical element 20 described above, the hologram unrecorded area 29 is irradiated with one light beam or two light beams incoherent light. Thus, the eyepiece prism 21 and the deflecting prism 22 can be joined. As a result, no interference fringes are generated in the hologram non-recorded area 29, so that the hologram 24 is not recorded. Therefore, it is possible to suppress the occurrence of ghosts due to the generation of unnecessary interference fringes in areas other than the hologram recording area 28. Further, since no interference fringes are generated in the hologram non-recorded area 29, a large difference in refractive index does not occur in the minute area of the adhesive layer 23, so that the adhesive layer 23 can be uniformly cured.

  At this time, in addition to the method for manufacturing a cemented optical element of the present invention, exposure to the hologram unrecorded area 29 described above can be realized by adding one of the following two pattern processes.

(Additional process 1)
Before the second step of manufacturing the cemented optical element 20, irradiation of light to the hologram unrecorded area 29 described above is an additional step 1. Fig.7 (a) is sectional drawing which shows the addition process 1 of the joining optical element in this invention. FIG.7 (b) is sectional drawing which shows another process of the addition process 1 of the joining optical element in this invention. The following cross-sectional view of the manufacturing method is a cross-sectional view of the adhesive layer 23b that is bonded at the same time as recording the hologram, and the description of the same parts as those of the above-described manufacturing method of the bonded optical element is omitted. .

  As shown in FIG. 7A, two light sources of polymerization start light for bonding the eyepiece prism 21 and the deflecting prism 22 by a polymerization reaction are arranged so as to sandwich the adhesive layer 23 therebetween. Then, the light shielding plates 26 a and 26 b are arranged so that the hologram recording area 28 is not irradiated with the polymerization start light. When the polymerization start light is irradiated in this state, the hologram unrecorded area 29 is cured by a polymerization reaction by the polymerization start light irradiated from the two light sources. Here, when the polymerization initiating light is coherent light such as laser light, the hologram unrecorded region 29 is irradiated so that the polarization directions thereof are orthogonal to each other by additionally arranging a wave plate 27a. The polymerization initiating light emitted from the two light sources can join the eyepiece prism 21 and the deflecting prism 22 without generating interference fringes even when irradiated to the hologram non-recorded area 29.

  Alternatively, as shown in FIG. 7B, by placing one light source and irradiating the polymerization initiation light, the hologram unrecorded area 29 is not interfered, and the eyepiece prism 21 is cured by polymerization reaction. And the deflection prism 22 can be joined. Also in this case, the light shielding plate 26b is disposed so that the hologram recording area 28 is not irradiated with the polymerization start light.

  The polymerization initiation light may be any light that initiates polymerization. For example, laser light, ultraviolet light, or visible light used when recording the hologram 24 can be used. The wavelength plate 27 may be any plate that changes the polarization direction of the polymerization initiating light in directions orthogonal to each other, and a half-wave plate or a quarter-wave plate can be used.

  In the additional step 1, the hologram non-recorded area 29 is polymerized and cured before the hologram 24 is recorded, and the eyepiece prism 21 and the deflecting prism 22 are joined and integrated, thereby generating a deviation of the adhesive layer 23. Can be prevented. Therefore, the workability when recording the hologram 24 can be facilitated.

(Additional process 2)
Simultaneously with the second step of manufacturing the cemented optical element 20, the light irradiation to the hologram unrecorded area 29 described above is performed as an additional step 2. FIG. 8A is a cross-sectional view showing the bonding optical element adding step 2 in the present invention. FIG.8 (b) is sectional drawing which shows another process of the addition process 2 of the joining optical element in this invention.

  As shown in FIG. 8A, the wave plates 27b and 27c are arranged corresponding to the hologram non-recorded area 29 irradiated with the coherent laser light emitted from one light source. Then, similarly to the second step, the hologram recording area 28 is irradiated with a coherent two-beam laser beam. Then, in the hologram non-recorded area 29, since the wave plates 27b and 27c are arranged, the laser beam is irradiated with light whose polarization direction is changed in a direction orthogonal to the other, so that an interference fringe is generated. Instead, the eyepiece prism 21 and the deflecting prism 22 can be joined by curing by a polymerization reaction.

  Alternatively, as shown in FIG. 8B, when irradiating the coherent two-beam laser beam irradiating the hologram recording area 28, the hologram unrecorded is irradiated with the laser beam emitted from one light source. The light shielding plates 26 c and 26 d are arranged corresponding to the region 29. Accordingly, since only one beam of laser light is irradiated to the hologram non-recorded area 29, the eyepiece prism 21 and the deflection prism 22 can be joined by polymerization hardening without producing interference fringes.

  As described above, the bonded optical element 20 can be easily manufactured as compared with the case where another process of irradiating the hologram unrecorded area 29 with the laser beam is provided.

(Second Embodiment)
FIG. 9 is a cross-sectional view showing another configuration example of the video display device. The video display device 2b has the same configuration as the video display device 2a shown in FIG. 3 except for the configuration of the cemented optical element 30.

  The video display device 2b of the present embodiment includes an LCD 34 composed of a light modulation element and a bonding optical element 30. The LCD 34 has the same configuration as the LCD 15 in the video display device 2a of the first embodiment. In the cemented optical element 30, the surfaces constituting the eyepiece prism 31 and the deflection prism 32 have a curved surface shape such as an aspherical surface or a free-form surface. The adhesive layer 33 that joins the eyepiece prism 31 and the deflecting prism 32 includes the adhesive layer 23 that records the hologram 24 described above.

  Thus, by forming the surfaces of the eyepiece prism 31 and the deflecting prism 32 in a curved surface shape, the cemented optical element 30 can have an arbitrary optical power. Therefore, even with such a configuration, it is possible to allow the observer to enlarge and observe the display image on the LCD 34 as a well-corrected aberration-corrected virtual image and to display an external image via the eyepiece prism 31, the deflection prism 32, and the adhesive layer 23. It is possible to observe well. In addition, the cemented optical element 30 can be provided with a function as a correction eyeglass lens.

(Third embodiment)
FIG. 10 is a sectional view showing still another configuration example of the video display device. The video display device 2c includes a light source and a light guide plate (not shown), an LCD 40, an eyepiece lens 41, and a cemented optical element 42. The eyepiece lens 41 constitutes an optical system that guides the image light emitted from the LCD 40 to the cemented optical element 42 as parallel light.

  In the bonded optical element 42, a plurality of prisms 43 to 47, which are transparent optical members, are bonded via a reflection mirror 48 and adhesive layers 54 to 56, respectively, and constitute a plate-like parallel plate. The reflection mirror 48 is a mirror that totally reflects incident light incident from the eyepiece lens 41. A hologram 51 that separates incident light between the prism 44 and the prism 45, between the prism 45 and the prism 46, and between the prism 46 and the prism 47 so that the transmitted light amount and the reflected light amount become a predetermined ratio. To 53 are recorded in the adhesive layers 54 to 56, respectively.

  The prisms 43 to 47 and the adhesive layers 54 to 56 described above are made of the same material as the eyepiece prism 21, the deflection prism 22, and the adhesive layer 23 described above.

  In the configuration 2c of the video display device in FIG. 10, light from the light source enters the light guide plate and illuminates the LCD 40 as a surface light source. The image light from the LCD 40 becomes parallel light by the eyepiece lens 41 and enters the cemented optical element 42. The light incident on the cemented optical element 42 is reflected by the reflecting mirror 48, guided through the prism 44, and incident on the adhesive layer 54 on which the hologram 51 is recorded. A part of the light incident on the adhesive layer 54 is transmitted therethrough, and the remaining light is reflected and guided to the outside (first optical pupil E1). The light transmitted through the adhesive layer 54 is guided through the prism 45 and enters the adhesive layer 55 on which the hologram 52 is recorded. A part of the light is transmitted therethrough, and the rest is reflected to the outside (second Guided to the optical pupil E2). The light transmitted through the adhesive layer 55 is guided through the prism 46 and is incident on the adhesive layer 56 on which the hologram 53 is recorded, and a part or all of the light is reflected to the outside (third optical pupil E3). Led to. Thereby, the observer can observe an image at any position of the optical pupils E1 to E3 corresponding to the adhesive layers 54 to 56 on which the holograms 51 to 53 are recorded.

  And the video display apparatus 2c of this invention can reduce the number of parts of the joining optical element 42 by recording the holograms 51-53 on the adhesive bond layers 54-56, and manufactures the video display apparatus 2c by extension. The process can be shortened.

  The light guided in each of the prisms 43 to 47 may be guided without being totally reflected by the two opposing surfaces of each of the prisms 43 to 47 as described above, or opposed to each other as shown in FIG. The two surfaces may be totally reflected and guided. Further, the video display device 2c is not limited to the above-described configuration, and may be configured with an adhesive layer that records a plurality of prisms and a plurality of holograms.

  When there are a plurality of adhesive layers on which holograms are recorded, a hologram (hologram 51 in FIG. 10) is recorded on the adhesive layer (adhesive layer 54 in FIG. 10) on the optically close side to the LCD 40. ) If the reflectance (diffraction efficiency) is set to be lower, the brightness of the image light reflected by each hologram can be made closer to each other, and an observer can observe a good image with little luminance unevenness. It becomes. Further, by adopting a configuration in which image light is reflected by a plurality of holograms, in addition to making the cemented optical element 42 thinner, it is possible to broaden the entire optical pupil formation range. Thereby, even when the position of the observer's pupil is shifted, it is possible to cause the observer to observe a good image at the position of the corresponding optical pupil.

  Of course, it is possible to configure the bonding optical element, the image display device, and thus the head mounted display by appropriately combining the above-described configurations and methods.

  The cemented optical element of the present invention can be used, for example, in an eyepiece optical system of an image display device that constitutes a head mounted display.

(A)-(c) is sectional drawing which shows the manufacturing process of the manufacturing method of the joining optical element of this invention. (A) is a top view which shows the head mounted display of this invention. (B) is a side view which shows the head mounted display of this invention. (C) is a front view which shows the head mounted display of this invention. It is sectional drawing which shows the video display apparatus of this invention. (A) is a top view which shows the eyepiece prism of the junction optical element of this invention. (B) is a side view showing an eyepiece prism of the cemented optical element of the present invention. (A) is a top view which shows the deflection | deviation prism of the joining optical element of this invention. (B) is a side view showing a deflection prism of the cemented optical element of the present invention. It is a top view which shows the joining optical element of this invention. (A) is sectional drawing which shows the addition process 1 of the joining optical element of this invention. (B) is sectional drawing which shows another process of the addition process 1 of the joining optical element of this invention. (A) is sectional drawing which shows the addition process 2 of the joining optical element of this invention. (B) is sectional drawing which shows another process of the addition process 2 of the joining optical element of this invention. It is sectional drawing showing the other structural example of the video display apparatus of this invention. It is sectional drawing showing the further another structural example of the video display apparatus of this invention. (A)-(e) is sectional drawing which shows the manufacturing method of the conventional joining optical element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head mounted display 2 Video display apparatus 3 Support member 11 Light source (illumination light source)
12 Video display element 15, 34, 40 LCD
20, 30, 42 Bonding optical element (eyepiece optical system)
21, 31 Eyepiece prism (transparent optical member)
22, 32 Deflection prism (transparent optical member)
23, 33, 54 to 56 Adhesive layer 24, 51 to 53 Hologram 28 Hologram recording area 29 Hologram unrecorded area 43 to 47 Prism (transparent optical member)

Claims (17)

A plurality of transparent optical members;
An adhesive layer that joins two adjacent transparent optical members,
A bonded optical element, wherein a hologram is recorded in the adhesive layer.   The bonded optical element according to claim 1, wherein the adhesive layer includes a polymerization initiator, a polymerizable monomer, a base polymer, and a sensitizing dye.   The bonding optical element according to claim 2, wherein the polymerizable monomer includes N-vinylcarbazole.   4. The bonded optical element according to claim 2, wherein the sensitizing dye is composed of one or more kinds of dyes and absorbs light in a wavelength region of red, green, and blue. 5.   The adjacent two said transparent optical members and the said adhesive bond layer which joins the said transparent optical member are comprised using the material which consists of an acryl-type or a cycloolefin type, The Claims 1- Claim characterized by the above-mentioned. Item 5. The bonded optical element according to any one of Items 4 to 5. Of the hologram,
When the refractive index of the bright part of the interference fringe is n1, and the refractive index of the dark part of the interference fringe is n2,
0.01 ≦ | n1-n2 | ≦ 0.05 (1)
The cemented optical element according to claim 1, wherein: The adhesive layer has a layer thickness of t μm.
10 ≦ t ≦ 300 (2)
The cemented optical element according to claim 1, wherein: A first step of disposing an uncured adhesive layer between two transparent optical members;
The adhesive layer is irradiated with a coherent two-beam laser beam to record interference fringes as a hologram in a partial region of the adhesive layer, and at the same time, the adhesive layer is formed by a polymerization reaction during recording of the hologram. And a second step of bonding the two transparent optical members by curing the bonding optical element. After the second step,
By irradiating the entire surface of the adhesive layer with ultraviolet rays, the sensitizing dye contained in the adhesive layer is decomposed, and at the same time, the monomer in the hologram non-recorded region is polymerized and cured to join the two transparent optical members. The method according to claim 8, further comprising a third step.   The hologram unrecorded area of the adhesive layer is irradiated with one light beam of laser light or two light beams of incoherent laser light, and the two transparent optical members are bonded by a polymerization reaction. A method for manufacturing a bonded optical element according to claim 8.   11. The method for manufacturing a bonded optical element according to claim 10, wherein the irradiation of the hologram layer in the adhesive layer with the laser is performed simultaneously with the recording of the hologram by the laser irradiation. Before recording a hologram in a partial area of the adhesive layer by laser irradiation,
9. The joining optical system according to claim 8, wherein a region other than a region where the hologram of the adhesive layer is recorded is irradiated with a polymerization initiating light for joining the two transparent optical members by a polymerization reaction. Device manufacturing method.   A cemented optical element manufactured by the manufacturing method according to claim 8.   The bonded optical element according to claim 1, wherein the hologram is a volume phase type reflection hologram. An illumination light source;
An image display element that displays light by modulating light from the light source;
A bonding optical element according to claim 14,
The image light from the image display element is incident from the incident surface of the bonding optical element, and is internally totally reflected a plurality of times to be guided to the hologram of the bonding optical element, and the image light is magnified and reflected by the hologram. An image display device characterized in that it emits light from the exit surface of the cemented optical element to the outside and guides it to the observer's eye as a virtual image, and simultaneously guides the light of the external image transmitted through the hologram to the eye of the observer.   The hologram has a positive non-axisymmetric optical power for enlarging an image displayed by the image display element, and at least a part of an eyepiece optical system that guides the display image to a viewer's eye as a virtual image The video display device according to claim 15, comprising: The video display device according to claim 15 or 16,
A head-mounted display, comprising: a support member that supports the video display device in front of an observer's eyes.

Images