JP2017075995A - Manufacturing method of junction type optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method that prevents adhesive from leaking from a bonding surface and does not generate an air bubble on the bonding surface when manufacturing a junction type optical element.SOLUTION: The manufacturing method includes: fixing prisms 2, 3 with a certain gap therebetween so that optical surfaces 2e, 3e for bonding are opposing to each other and transmission optical surfaces 2a, 2b; 3a, 3b are both continuously positioned; sealing a gap 4v of the prisms 2, 3 for both of the transmission optical surfaces 2a, 2b; 3a, 3b; sealing a gap 4v for both of lateral faces 2c, 2d; 3c, 3d positioned vertically to the transmission optical surfaces 2a, 2b; 3a, 3b and not receiving video light and external light; sucking out air 7 in the gap 4v from a lateral face sealing member 14a sealing the lateral faces 2c, 3c; injecting adhesive 4 into the gap 4v from the lateral face sealing member 15a sealing the lateral faces 2d, 3d; and curing the adhesive 4 to bond the prisms 2, 3.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a cemented optical element, for example, a method for manufacturing a cemented prism having a hologram member for image projection between two prisms.

  A hologram which is one of optical elements is very useful as a combiner mounted on an optical see-through display (head mounted display (HMD), head-up display, etc.). For example, if a hologram is used by being sandwiched between two prisms, it is possible to obtain an advantage that the hologram is hardly affected by external environment such as humidity and oxygen. Further, by sandwiching the hologram between the joint surfaces between the prisms, the image light provided from the image display element can be totally reflected inside the prism to be guided to the hologram, and projected onto the observer's eyes with the hologram. Then, by optimizing the hologram characteristics, prism shape, and the like, it is possible to secure the see-through property for displaying the image superimposed on the external field while maintaining the optical performance of the hologram.

  In order to join two prisms as described above, an adhesive is usually used (for example, refer to Patent Document 1). As a bonding method using an adhesive, after applying the adhesive to one prism, the other prism is brought close to a position where there is a necessary interval in terms of optical characteristics, and the adhesive is spread out in the movement, It is common practice to fill the adhesive between the prisms over the entire joint surface.

JP 2014-38227 A

  However, in the method of filling the adhesive as described above, since the adhesive cannot be stopped at the outer peripheral contour portion of the prism, the adhesive overflows onto the prism surface (transmission optical surface) through which image light and external light are transmitted. It will be. The adhesive overflowing the transmission optical surface must be removed, but the transmission optical surface may be damaged in the operation of removing the adhesive. Further, when the overflowing adhesive cannot be completely removed, the adhesive residue lowers the flatness of the transmissive optical surface, leading to a reduction in image surface property.

  Therefore, if it is possible to prevent the adhesive from overflowing to the transmission optical surface, it is possible to solve the problem caused by the transmission optical surface. However, another problem arises if the adhesive is not allowed to overflow to the transmissive optical surface. For example, in the operation of filling the adhesive, bubbles may be generated in the adhesive, and the bubbles deteriorate the see-through performance of the external image, and when the image light hits the bubbles generated on the joint surface, It will cause deterioration. In order to discharge air bubbles generated in the adhesive from the joint surface, it is effective to overflow the adhesive in a large amount. However, even if a large amount of the adhesive is overflowed, the bubbles generated on the joint surface may not be completely removed. Further, as described in Patent Document 1, it is difficult to completely remove bubbles even if the shape of the prism surface to which the adhesive is applied is devised, and the complexity of the prism surface shape increases the optical performance. There is also a risk of lowering.

  The present invention has been made in view of such a situation, and the object thereof is to prevent the adhesive from overflowing outside the bonding surface and to produce bubbles on the bonding surface when manufacturing the bonded optical element. An object of the present invention is to provide a manufacturing method that does not.

In order to achieve the above object, the method for manufacturing a junction optical element according to the first aspect of the present invention is guided by the transparent member between two transparent members each having a transmission optical surface through which light passes. An optical functional member that acts optically on light is located, and a manufacturing method of a bonded optical element having a structure in which the two transparent members are bonded with an adhesive via the optical functional member,
A step of fixing the two transparent members at regular intervals so that the two transparent members face each other on the optical functional member side and the transmissive optical surfaces are continuously located on both sides; When,
Sealing the gap between the two transparent members on both sides of the transmission optical surface;
Sealing each of the gaps between the two transparent members on both sides of the side surface that is perpendicular to the transmission optical surface and on which the image light and external light are not incident; and
Sucking out the air in the gap between the two transparent members from the one sealing member sealing the side surface;
Injecting the adhesive into the gap between the two transparent members from the other sealing member sealing the side surface;
Curing the adhesive injected into the gap and joining the two transparent members;
It is characterized by having.

  According to a second aspect of the present invention, there is provided a method for manufacturing a bonded optical element according to the first aspect, wherein at least one of air flow rate control in the step of sucking out air and adhesive flow rate control in the step of injecting the adhesive. It is characterized by performing.

  According to a third aspect of the present invention, there is provided a method for producing a junction-type optical element according to the first or second aspect, wherein the adhesive is pressurized in the step of injecting the adhesive.

  According to a fourth aspect of the present invention, there is provided a method for manufacturing a bonded optical element according to any one of the first to third aspects, wherein the adhesive is a photocurable adhesive, and the adhesive is removed from a position where air is sucked out. The irradiation position of the light that cures the adhesive is moved to the injection position.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a junction optical element according to any one of the first to fourth aspects, wherein in the step of fixing the two transparent members, the other transparent member is relative to the one transparent member. It is characterized by adjusting the general position.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a junction-type optical element according to any one of the first to fifth aspects, wherein the gaps between the two transparent members on both sides of the side surface are respectively sealed with a sealing member. In the stopping step, a sheet member made of a hot melt adhesive is used for connection between the two transparent members and the sealing member sealing the side surface.

  According to a seventh aspect of the present invention, there is provided a method for manufacturing a junction optical element according to any one of the first to fifth aspects, wherein the gaps between the two transparent members on both sides of the side surface are sealed with a sealing member. In the stopping step, a sheet member made of a silicone gel rubber material is used for connection between the two transparent members and the sealing member sealing the side surface.

  According to an eighth aspect of the present invention, there is provided a method for manufacturing a junction-type optical element according to any one of the first to seventh aspects, wherein the optical function member is a hologram member.

  According to a ninth aspect of the present invention, there is provided the method for manufacturing a junction-type optical element according to any one of the first to eighth aspects, wherein the optical function member approaches an end on each of the air suction side and the adhesive injection side. It has the shape which becomes narrow as the width increases.

  According to the manufacturing method of the present invention, when manufacturing a bonded optical element, it is possible to prevent the adhesive from overflowing outside the bonded surface and to prevent air bubbles from being present on the bonded surface. Since the adhesive does not overflow to the transmission optical surface through which the image light and the external light are transmitted, the image surface property is not deteriorated by the adhesive residue. Since the operation of removing the adhesive overflowing the transmission optical surface is not necessary, the transmission optical surface is not damaged in the operation of removing the adhesive. In addition, since it is possible to prevent bubbles from being generated in the adhesive during the operation of filling the adhesive, it is possible to suppress deterioration of the see-through performance and image deterioration of the external image due to the bubbles. There is no need to complicate the shape. Therefore, it is possible to manufacture a junction type optical element that does not deteriorate optical characteristics.

The perspective view which shows an example of a joining prism. FIG. 2 is a perspective view showing two prisms constituting the cemented prism of FIG. 1 as viewed from the optical surface side for bonding. FIG. 2 is a schematic cross-sectional view schematically showing an example of an image display device having the cemented prism of FIG. 1. Sectional drawing which shows typically the example of schematic structure of the prism joining apparatus used for one Embodiment of the manufacturing method of a joining prism. The perspective view which shows the prism position adjustment mechanism used for the prism joining apparatus of FIG. The perspective view which shows the upper sealing part, lower sealing part, and side surface sealing part which are used for the prism joining apparatus of FIG. The perspective view which shows the connection state by the sheet | seat member of a prism and a side surface sealing member. The perspective view which shows operation | movement of the flow volume adjustment mechanism which comprises the side surface sealing part of FIG. The schematic sectional drawing which shows the other specific example of the flow volume adjustment mechanism which comprises the side surface sealing part of FIG. Sectional drawing which shows typically the example of schematic structure of the prism joining apparatus carrying an adhesive agent pressurization system. The top view which shows typically a mode that the adhesive agent injected between prisms spreads and spreads. Sectional drawing which shows typically the example of schematic structure of the prism joining apparatus carrying a UV light source movement system.

  Hereinafter, the manufacturing method of the junction type optical element concerning the present invention, etc. are explained, referring to drawings. In addition, the same code | symbol is mutually attached | subjected to the part which is the same in each embodiment etc., and the corresponding part, and duplication description is abbreviate | omitted suitably.

  FIG. 1 shows a cemented prism 1 having a lens function as an example of a cemented optical element manufactured by the method according to the present invention. FIGS. 2 (A) and 2 (B) show the cemented prism 1 2. The two prisms 2 and 3 are shown as viewed from the bonding optical surfaces 2e and 3e, respectively. The cemented prism 1 includes prisms 2 and 3 (transparent member) made of a transparent resin or glass; a hologram member 5 (optical function member) and the like, and has the hologram member 5 between the prism 2 and the prism 3. It has a structure.

  The hologram member 5 is affixed to the bonding optical surface 2 e of the prism 2, and the prism 2 and the prism 3 are bonded together with the hologram member 5 sandwiched by an adhesive 4 provided between the prisms 2 and 3. . That is, the prism 2 and the prism 3 are bonded by the adhesive 4 provided between the prism 2 and the hologram member 5 and the prism 3, and the bonding optical surfaces 2 e and 3 e are bonded by the adhesive 4. It has a structure in which the joint surface is configured. The hologram member 5 is bonded to the bonding optical surface 3 e of the prism 3, and the hologram member 5 is bonded between the prism 2 and the prism 3 by the adhesive 4 provided between the prism 2, the hologram member 5, and the prism 3. You may join so that it may be pinched | interposed.

  FIG. 3 shows a schematic vertical cross-sectional structure of an image display device 10 including the cemented prism 1 and the display element 9. Examples of the display element 9 include a reflective or transmissive liquid crystal display (LCD), a digital micromirror device, and an organic EL (organic electro-luminescence) display. . Furthermore, an illuminating device for illuminating the display element 9 may be arranged, and the illuminating device is composed of a light source such as an LED (light emitting diode) and a condensing optical element (lens, mirror, etc.). The thing provided with the illuminating device etc. is mentioned.

  The hologram member 5 constituting the cemented prism 1 is configured such that, for example, by performing hologram exposure (two-beam exposure of object light and reference light) by irradiating the hologram recording medium with laser light from two directions, interference fringes are generated in a hologram. It is recorded. When the hologram member 5 is sandwiched between the two prisms 2 and 3 and the prism 2 and the prism 3 are bonded with the adhesive 4, the bonded prism 1 in a state in which hologram reproduction is possible is obtained. In hologram reproduction, when image light (reproduction illumination light) L1 enters the hologram member 5, light having a specific wavelength in the image light L1 is diffracted and reflected in a wavelength selective manner as reproduction image light L2. The reproduced video light L2 enters the observer's eye EY together with the external light L3 transmitted through the hologram member 5. Therefore, the observer can observe a high-quality image through the cemented prism 1 and can also observe an external image (outside scene) through the cemented prism 1 in a see-through manner.

  Of the prisms 2 and 3 constituting the cemented prism 1, the prism 2 includes transmission optical surfaces 2a and 2b, side surfaces 2c and 2d, and a bonding optical surface 2e. The prism 3 includes the transmission optical surface 3a. , 3b, side surfaces 3c and 3d, and a bonding optical surface 3e. The transmission optical surfaces 2a and 2b constituting both surfaces of the prism 2 and the transmission optical surfaces 3a and 3b constituting both surfaces of the prism 3 are planes through which the external light L3 is transmitted, and are positioned parallel to each other. The side surfaces 2c, 2d; 3c, 3d are surfaces that are respectively perpendicular to the transmissive optical surfaces 2a, 2b; 3a, 3b, and on which the image light L1 and the external light L3 are not incident. The surface of the prism 2 on the hologram member 5 side is a bonding optical surface 2e, and the surface of the prism 3 on the hologram member 5 side is a bonding optical surface 3e. The bonding optical surfaces 2e and 3e are respectively formed of a convex surface and a concave surface having curvature only in one direction, but the surface shape is not limited to a curved surface shape, and may be a shape as required, for example, a planar shape.

  In the prisms 2 and 3, the bonding optical surface 2e and the bonding optical surface 3e face each other, and the transmission optical surface 2a and the transmission optical surface 3a, and the transmission optical surface 2b and the transmission optical surface 3b are continuous on both surfaces. It is fixed at a certain interval through the adhesive 4 and the hologram member 5 so as to be positioned. That is, the transmission optical surface 2a, the adhesive 4, and the transmission optical surface 3a constitute a plane, and the transmission optical surface 2b, the adhesive 4, and the transmission optical surface 3b constitute a plane. With this configuration, the external light L3 is not easily affected when it passes through the prisms 2 and 3, so that an external image can be observed well. Similarly, the side surfaces 2c, 2d; 3c, 3d form one plane with the side surface 2c, the adhesive 4, and the side surface 3c, and the side surface 2d, the adhesive 4, and the side surface 3d form one plane. However, this configuration is effective for suppressing the generation of unnecessary light, for example.

  The hologram member 5 optically acts on the image light L1 guided inside the prism 2 (that is, diffracts and reflects only light in a predetermined wavelength region of the image light L1 with positive power). As a lens function for image projection and located between the prisms 2 and 3 (that is, between the bonding optical surface 2e and the bonding optical surface 3e). The prisms 2 and 3 are joined via the hologram member 5 with an adhesive 4 (photo-curable adhesive) that cures with light of a certain wavelength. Here, it is assumed that the adhesive 4 is an ultraviolet curable adhesive that is cured by irradiation with ultraviolet rays (UV).

  As described above, the cemented prism 1 uses the display image as a virtual image so that the image of the display element 9 overlaps the external image via the hologram member 5 between the cemented prisms 2 and 3. 3) It functions as an eyepiece optical system for projection display with see-through. Therefore, the hologram member 5 is desirably a volume phase type reflection hologram. Since the volume phase type reflection hologram has a high light transmittance of the external image, if the volume phase type reflection hologram is used as the hologram member 5, the observer can clearly observe the external image together with the display image. become.

  The hologram member 5 is, for example, a hologram sheet in which a hologram photosensitive material is held on a resin sheet, and a region to be attached to the bonding optical surface 2e is cut out in a predetermined shape, and the cut out region (cutout region) is a resin sheet. And is attached to the bonding optical surface 2e and exposed to the hologram photosensitive material in the cut out area. The hologram member 5 thus formed on the bonding optical surface 2e can impart a holographic optical function (positive power diffraction reflection function) to the bonding surface including the bonding optical surfaces 2e and 3e.

  As shown in FIG. 1 and the like, since the hologram member 5 is used in a state of being embedded in the prisms 2 and 3 (that is, in a state of being sandwiched between the two prisms 2 and 3), an external environment such as humidity and oxygen is used. (The prevention of environmental degradation). Further, since the image light L1 provided from the display element 9 can be totally reflected inside the prism 2 and guided to the hologram member 5 by the configuration embedded in the prisms 2 and 3, the image light L1 can be used without waste. Thus, a bright image can be provided to the observer. In addition, the display element 9 can be arranged at a position away from the cemented prism 1, and a wide field of view of the observer with respect to the outside world can be secured. Then, by optimizing the shape of the prisms 2 and 3, the shape of the hologram member 5, and the like, the see-through property (combiner function) of the external image can be ensured while maintaining the optical performance of the hologram member 5.

  Next, a method for manufacturing the above-described cemented prism 1 will be described. This manufacturing method is characterized by a method of joining the two prisms 2 and 3 using the adhesive 4. FIG. 4 schematically shows a schematic cross-sectional configuration of the prism bonding apparatus U1 used for the bonding method. FIG. 4A shows the prism bonding apparatus U1 from the front side, and FIG. 4B shows the prism bonding apparatus U1 from the side surface side.

  The prism bonding apparatus U1 includes a prism mounting portion 11 that positions and fixes the two prisms 2 and 3, an upper sealing portion 12 that seals the gap 4v between the prisms 2 and 3 from the transmission optical surfaces 2b and 3b, and a prism. A lower sealing portion 13 that seals the gaps 4v of 2 and 3 from the transmission optical surfaces 2a and 3a side, a side sealing portion 14 that seals the gap 4v of the prisms 2 and 3 from the side surfaces 2c and 3c, and a prism. A side sealing part 15 that seals the gaps 4v between the side surfaces 2d and 3d, an air suction part 16 that leads to the side sealing part 14, an adhesive injection part 17 that leads to the side sealing part 15, And a light source unit 18 for curing the adhesive 4.

  The manufacturing method of the cemented prism 1 using the prism bonding apparatus U1 includes a fixing step of adjusting and fixing the positions of the prisms 2 and 3, a sealing step of the transmission optical surfaces 2a and 2b; 3a and 3b, and a side surface 2c, 2d; 3c, 3d sealing step, step of sucking air 7 from the gap 4v between the prisms 2 and 3, step of injecting the adhesive 4 into the gap 4v of the prisms 2 and 3, and step of curing the adhesive 4 And.

  In the fixing process of the prisms 2 and 3, the prisms 2 and 3 oppose the bonding optical surfaces 2e and 3e located on the hologram member 5 side, and the transmission optical surfaces 2a and 2b; 3a and 3b are continuous on both surfaces. The prisms 2 and 3 are fixed at a predetermined interval (gap 4v) so as to be positioned at the position. For this purpose, a prism position adjusting mechanism 19 shown in FIG. 5 is used. The prism position adjusting mechanism 19 is incorporated in the prism mounting portion 11 and includes a clamp 19a; a micro head 19b; positioning members x1, x2, x3, y1, y2, y3, and the like.

  As shown in FIG. 2A, the prism 2 is provided with three reference surfaces Y1, Y2, and Y3. As shown in FIG. 2B, the prism 3 has three reference surfaces X1. , X2, X3 are provided. On the other hand, the positioning members y1, y2, and y3 are formed with walls that determine the position by contacting the reference surfaces Y1, Y2, and Y3 of the prism 2, respectively, and the positioning members x1, x2, and x3 each have a reference for the prism 3. Walls that determine the position by contacting the surfaces X1, X2, and X3 are formed. The prism 3 is fixed in a state of being sandwiched by clamps 19a, and the positioning members x1 and x2 of the prism 3 are movable by the micro head 19b or the like (arrow mp in FIG. 5) while the position of the prism 2 is fixed. ing.

  The size of the gap 4v between the prisms 2 and 3 is affected by the amount of cure shrinkage of the adhesive 4, and the cure shrinkage causes the prisms 2 and 3 to be deformed. An accuracy of about 20 μm is required for the size of the gap 4v that does not cause deterioration of optical characteristics. Therefore, if the prism position adjusting mechanism 19 is used in the process of fixing the prisms 2 and 3, the relative position of the prism 3 with respect to the prism 2 can be finely adjusted, and the position relative to variations in prism manufacturing accuracy and the like can be adjusted. Correction is possible. Accordingly, it is possible to manufacture the cemented prism 1 with less image plane deterioration. The prisms 2 and 3 are sucked from the bottom surfaces of the prisms 2 and 3 (that is, the transmission optical surfaces 2a and 3a) while being applied to the walls of the positioning members y1, y2 and y3; x1, x2 and x3. (The arrow ma in FIG. 4B) is fixed.

  In the sealing step of the transmission optical surfaces 2a, 2b; 3a, 3b, the slit-shaped gap 4v between the prisms 2, 3 is sealed on both surfaces of the transmission optical surfaces 2a, 2b; 3a, 3b (FIG. 4). (B) etc.). For the sealing, an upper sealing portion 12 shown in FIG. 6A and a lower sealing portion 13 shown in FIG. 6B are used. The upper sealing part 12 is provided with an upper sealing member 12a, and the lower sealing part 13 is provided with a lower sealing member 13a. The upper and lower sealing members 12a and 13a are preferably made of a rubber material having a Shore A40 (hardness) or less. Further, since there is contact with the adhesive 4, the material is preferably water-repellent. In addition, since the light irradiation for hardening the adhesive agent 4 is required in a process described later, the upper sealing portion 12 (FIG. 6A) includes a transparent material (for example, transparent) including the upper sealing member 12a. Resin or glass).

  The upper sealing portion 12 and the lower sealing portion 13 are brought close to the prisms 2 and 3, and the upper and lower sealing members 12a and 13a are brought into close contact with the prisms 2 and 3 (FIG. 4). The energizing force of the springs 12b and 13b is used for sealing by the close contact. The amount of pressure applied for sealing becomes a force necessary for injection of the adhesive 4. That is, a force capable of sealing against the pressure of the adhesive 4 when the adhesive 4 is injected is required as the urging force of the springs 12b and 13b. By thus sealing the transmission optical surfaces 2a, 2b; 3a, 3b, it is ensured that the adhesive 4 overflows from the bonding optical surfaces 2e, 3e to the transmission optical surfaces 2a, 2b; 3a, 3b. Can be prevented.

  In the sealing process of the side surfaces 2c, 2d; 3c, 3d, the side surfaces 2c, 2d; 3c, which are positioned perpendicular to the transmission optical surfaces 2a, 2b; 3a, 3b and where the image light L1 and the external light L3 are not incident. , 3d (transmission optical surfaces 2a, 2b; both side surfaces adjacent to 3a, 3b), the slit-shaped gap 4v between the prisms 2 and 3 is sealed (FIG. 4B, etc.). For the sealing, side sealing portions 14 and 15 whose sectional structure is shown in FIG. 6C are used. That is, the side surface sealing portions 14 and 15 are brought close to the prisms 2 and 3 and the side surface sealing members 14a and 15a are brought into close contact with the prisms 2 and 3 (FIG. 4), so that they are located between the prisms 2 and 3. The slit-shaped gap 4v is sealed.

  Both of the side sealing parts 14 and 15 have the same configuration, and include side sealing members 14a and 15a having the same configuration and shutters (valves) 14b and 15b having the same configuration, and side sealing. Openings 14h and 15h are formed in the members 14a and 15a, respectively. The side sealing members 14a and 15a are preferably made of a rubber material having a Shore A40 (hardness) or less. When the side surface sealing members 14a and 15a are made of a rubber material, the side surface sealing members 14a and 15a have tubes or pipes, even if the side surface sealing members 14a and 15a are not previously formed with openings 14h and 15h. It is also possible to connect while maintaining the sealed state by utilizing the elasticity of the rubber material.

  In consideration of complete sealing of the corners of the transmission optical surfaces 2a, 2b; 3a, 3b and the side surfaces 2c, 2d; 3c, 3d and peeling of the side sealing members 14a, 15a after joining, For sealing with the sealing members 14a and 15a, it is effective to use a sheet member such as a hot melt adhesive or a silicone gel rubber material. That is, in the sealing process of the side surfaces 2c, 2d; 3c, 3d, as described above, the sheet-like hot melt adhesive or the sheet-like silicone system is used to connect the prisms 2, 3 and the side surface sealing members 14a, 15a. It is preferable to use a gel rubber material. An example of the connection state by the sheet member 22 which consists of the hot-melt-adhesive or a silicone type gel rubber material is shown in FIG.

  As shown in FIG. 7, the sheet member 22 is provided so that the opening 22h is positioned in the slit-shaped gap 4v between the side surfaces 2c and 3c, the position of the opening 14h is aligned with the opening 22h, and the side surface sealing is performed via the sheet member 22. The stop member 14a is affixed to the side surfaces 2c and 3c. The same applies to the case where the side surface sealing member 15a is attached to the side surfaces 2d and 3d via the sheet member 22. For sealing the side surfaces 2c, 2d; 3c, 3d, it is necessary to provide a mechanism (such as a flow rate adjusting mechanism 20, which will be described later) for flowing the air 7 or the adhesive 4 as a fluid. Since it is necessary to remove the side sealing members 14a and 15a after joining, the peelability is a necessary function. From these viewpoints, the sheet member 22 made of a hot-melt adhesive, a silicone gel rubber material, or the like is suitable. By using the sheet member 22, the sealing by the side sealing member 14a and the peeling thereof are appropriate. It becomes possible to do. And the effect that the peelability of the adhesive agent 4 is good and the appearance quality is not deteriorated is obtained.

  In the step of sucking out the air 7 from the gap 4v between the prisms 2 and 3, the air 7 in the gap 4v between the prisms 2 and 3 is sucked out from the side surface sealing member 14a sealing the side surfaces 2c and 3c (FIG. 4). . A tube or a pipe is connected to the opening 14h of the side surface sealing member 14a, and the side surface sealing portion 14 and the air suction portion 16 are connected. The air suction unit 16 includes a suction pump (vacuum pump) 16a, a pressure gauge 16b (80 kPa), and the like, so that the air 7 in the gap 4v between the prisms 2 and 3 can be sucked out by the suction pump 16a. It has become. An object other than the air 7 (adhesive 4, dust, etc.) is trapped as appropriate.

  A flow rate adjusting mechanism 20 shown in FIG. 8 is used to control the flow rate of the air 7 in the flow path from the gap 4v between the prisms 2 and 3 to the suction pump 16a. The flow rate adjusting mechanism 20 is incorporated in the side surface sealing portion 14, and the flow rate of the air 7 can be controlled ON / OFF by moving the mounted shutter 14 b. FIG. 8A shows the shutter fully open state (ON), and FIG. 8C shows the shutter fully closed state (OFF). When the air 7 is sucked between the prisms 2 and 3 by the suction pump 16a, the shutter 14b is fully opened (ON), but the open / closed state of the shutter 15b can be changed as appropriate as will be described later.

  In the step of injecting the adhesive 4 into the gap 4v between the prisms 2 and 3, the adhesive 4 is injected into the gap 4v between the prisms 2 and 3 from the side surface sealing member 15a sealing the side surfaces 2d and 3d. (FIG. 4). A tube or a pipe is connected to the opening 15h of the side surface sealing member 15a, and the side surface sealing portion 15 and the adhesive injection portion 17 are connected. The adhesive injection part 17 is composed of a syringe 17 a or the like in which the adhesive 4 is stored, and can inject the adhesive 4 into the gap 4 v between the prisms 2 and 3. Since the gap 4v between the prisms 2 and 3 is in a negative pressure state in advance in the step of sucking out the air 7, the generation of bubbles when the adhesive 4 is injected can be effectively eliminated.

  A flow rate adjusting mechanism 20 shown in FIG. 8 is used to control the flow rate of the adhesive 4 in the flow path from the gap 4v between the prisms 2 and 3 to the syringe 17a. The flow rate adjusting mechanism 20 is incorporated in the side sealing portion 15, and the flow rate of the adhesive 4 can be controlled from 0 to the maximum amount by moving the mounted shutter 15 b. In FIG. 8A, the flow rate of the adhesive 4 becomes the maximum amount when the shutter is fully opened, and in FIG. 8C, the flow rate of the adhesive 4 becomes 0 when the shutter is fully closed, and in FIG. The flow rate of the adhesive 4 can be adjusted.

  In the step of injecting the adhesive 4, the flow rate of the adhesive 4 can be controlled by controlling the flow rate of the adhesive 4 with the flow rate adjusting mechanism 20 as described above. Since the flow rate of the adhesive 4 is affected by the viscosity of the adhesive 4 to be used, for example, when the viscosity becomes high, the flow rate becomes slow. Therefore, the force that pulls the adhesive 4 generates the internal stress of the adhesive 4. Become. Therefore, by providing the flow rate adjusting mechanism 20 that controls the flow rate of the fluid (air 7, adhesive 4), the negative pressure state of the gap 4v between the prisms 2 and 3 can be changed. It is possible to set optimum conditions for factors that change the flow rate such as viscosity. In the step of sucking out the air 7, the flow rate adjustment mechanism 20 may control the flow rate of the air 7.

  As the opening / closing operations of the shutters 14b and 15b in the air 7 suction step and the adhesive 4 injection step, the following three types can be cited. In the first type of opening / closing operation, the shutter 14b is fully opened (FIG. 8A), the shutter 15b is fully opened (FIG. 8A), or the flow rate is adjusted (FIG. 8B). The adhesive 4 is injected while sucking. The flow rate adjustment state (FIG. 8B) is appropriately set according to the viscosity of the adhesive 4 (for example, the flow rate is constant). In order to increase the degree of vacuum of the gap 4v between the prisms 2 and 3 to suppress the generation of bubbles and more effectively remove the generated bubbles, or to improve the flow of the adhesive 4, It is preferable to perform the following second and third types of opening / closing operations.

  In the second type of opening / closing operation, the air 14 is sucked when the shutter 14b is fully opened (FIG. 8A) and the shutter 15b is fully closed (FIG. 8C). The adhesive 4 is injected by closing the shutter 15b (FIG. 8C) and fully opening the shutter 15b (FIG. 8A) or adjusting the flow rate (FIG. 8B). The flow rate adjustment state (FIG. 8B) is appropriately set according to the viscosity of the adhesive 4 (for example, the flow rate is constant).

  In the third type of opening / closing operation, the air 14 is sucked when the shutter 14b is fully opened (FIG. 8A) and the shutter 15b is fully closed (FIG. 8C). After the suction is completed, the shutter 14b is fully opened. In the state (FIG. 8A), the adhesive 4 is injected by setting the shutter 15b to the fully open state (FIG. 8A) or the flow rate adjustment state (FIG. 8B). The flow rate adjustment state (FIG. 8B) is appropriately set according to the viscosity of the adhesive 4 (for example, the flow rate is constant).

  For the side sealing portions 14 and 15 (FIG. 6C), a flow rate adjusting mechanism 21 shown in FIG. 9 may be used instead of the flow rate adjusting mechanism 20 (FIG. 8). The flow rate adjusting mechanism 20 adjusts the opening and closing of the flow path by moving the plate-like shutters 14b and 15b, whereas the flow rate adjusting mechanism 21 adjusts the opening and closing of the flow path by moving the rod-shaped valve 21a (arrow mv). Is to do. Although the flow rate adjusting mechanism 21 shown in FIG. 9 is mounted on the side sealing portion 15 and has a structure suitable for adjusting the flow rate of the adhesive 4, it is mounted on the side sealing portion 14 and air 7. It is also possible to adjust the flow rate.

  Even if the adhesive injection part 17 is configured to press the syringe 17a (FIG. 4A) and push out the adhesive 4 in order to enable proper injection according to the viscosity of the adhesive 4. Good. FIG. 10 schematically shows a schematic cross-sectional configuration of a prism bonding apparatus U2 equipped with a pressurizing system 17b made of a dispenser or the like for the pressurization. FIG. 10A shows the prism bonding device U2 from the front side, and FIG. 10B shows the prism bonding device U2 from the side surface side. In the prism bonding apparatus U <b> 1, since the flow rate is controlled only by the force for discharging the air 7, the upper limit of the flow rate is determined by the viscosity of the adhesive 4. On the other hand, the prism bonding apparatus U2 is equipped with a pressurizing system 17b for extruding the adhesive 4 by air pressure, so that the flow rate of the adhesive 4 is increased by pressurizing the adhesive 4 in the step of injecting the adhesive 4. At the same time, the internal stress of the adhesive 4 can be relaxed.

  In the gap 4v between the prisms 2 and 3, the hologram member 5 as an optical functional member is located. The hologram member 5 has a shape that becomes narrower as it approaches the end on the side sealing part 14 side (air suction side) and the side sealing part 15 side (adhesive injection side) (that is, as shown in FIG. The tip has a gently pointed shape. Therefore, the adhesive 4 flowing into the gap 4v smoothly flows from the injection-side opening 15h to the air suction-side opening 14h, and the flow does not stagnate. FIG. 11 schematically shows how the adhesive 4 injected between the prisms 2 and 3 flows and spreads.

  As shown in FIG. 11, the hologram member 5 has a central equal width portion 5a and narrow width portions 5b at both ends thereof, and the narrow width portions 5b become narrower as they approach the end portions. It has a shape. Therefore, even if the adhesive 4 flows into the gap 4v, the load applied to the hologram member 5 is small and the resistance received by the adhesive 4 is also small. Even if the injected adhesive 4 hits the end of the narrow portion 5b, it is smoothly separated in the width direction and flows along the narrow portion 5b. For this reason, it can reduce that the adhesives 4 collide violently in the vicinity of the narrow part 5b, and its circumference | surroundings, and the surrounding air 7 is included, As a result, generation | occurrence | production of the bubble 8 is suppressed. Moreover, since the adhesive 4 in the vicinity of the narrow width portion 5b flows along the narrow width portion 5b, even if the bubbles 8 are generated for some reason in the vicinity of the narrow width portion 5b, the bubbles 8 are formed as shown in FIG. It is carried downstream by the flow of the adhesive 4 and discharged together with the unnecessary adhesive 4. Therefore, the bubbles 8 do not stay in the gap 4v between the prisms 2 and 3, and the bubbles 8 can be reliably reduced. Even if dust is mixed in the gap 4v between the prisms 2 and 3, it can be discharged by the flow of the adhesive 4 as described above.

  After the injection of the adhesive 4 is completed, the side sealing portions 14 and 15 are separated from the prisms 2 and 3. Then, in the step of curing the adhesive 4, the adhesive 4 is cured and the prisms 2 and 3 are joined. The light source 18 is used to cure the adhesive 4 (FIGS. 4B and 10B), and light of a certain wavelength is applied to the adhesive 4 between the bonding optical surfaces 2e and 3e by the light source 18. Irradiate to cure. Here, since an ultraviolet curable adhesive is assumed as the adhesive 4, a UV light source that performs ultraviolet irradiation is used for the light source unit 18. After the curing of the adhesive 4 (UV curing) is completed, the upper sealing portion 12 and the lower sealing portion 13 are separated from the prisms 2 and 3, and the prisms 2 and 3 are detached from the prism mounting portion 11.

  FIG. 12 schematically shows a schematic cross-sectional configuration of the prism bonding apparatus U3 on which the UV light source moving system 18a is mounted. 12A shows the prism bonding apparatus U3 from the front side, and FIG. 12B shows the prism bonding apparatus U3 from the side surface side. This UV light source moving system 18 a is for controlling the curing direction of the adhesive 4. A light source unit 18 is disposed on a uniaxial slider 18b constituting the UV light source moving system 18a, and the light source unit 18 moves from the side sealing unit 14 side (air suction side) to the side sealing unit 15 side (adhesive). It can be moved to the injection side (arrow mu in FIG. 12A). That is, the light irradiation position for curing the adhesive 4 is moved from the position for sucking out the air 7 to the position for injecting the adhesive 4.

  When the photocurable adhesive 4 is cured by light irradiation, the volume of the adhesive 4 filled in the gap 4v between the prisms 2 and 3 decreases due to the shrinkage of the adhesive 4 during curing. It is necessary to supply the adhesive 4 anew by the reduced amount. However, the adhesive 4 is supplied from the side of the adhesive injection part 17 storing the adhesive 4 because of the internal force generated by pulling the adhesive 4. It is preferable for relaxing the stress. When the ultraviolet light irradiation is performed while the light source unit 18 moves from the side sealing unit 14 side to the side sealing unit 15 side, the adhesive 4 is also cured from the side sealing unit 14 side to the side sealing unit 15 side. Thus, the adhesive 4 proceeds with curing while compensating for the deficiency due to curing shrinkage. Accordingly, it is possible to appropriately supply the adhesive 4 from the adhesive injection portion 17 in accordance with the curing shrinkage of the adhesive 4, and to appropriately move the cured area of the adhesive 4 and relieve internal stress. It becomes possible.

  According to the manufacturing method described above, the gap 4v between the prisms 2 and 3 is sealed on the transmission optical surfaces 2a, 2b; 3a, 3b side and the side surfaces 2c, 2d; 3c, 3d side, and the air 7 in the gap 4v is sealed. In this case, the adhesive 4 is injected into the negative pressure state, and the adhesive 4 is injected. Therefore, when the cemented prism 1 is manufactured, the adhesive 4 does not overflow outside the joint optical surfaces 2e and 3e, and the joint prism 1 is used. It is possible to prevent the bubbles 8 from being present in the adhesive 4 between the optical surfaces 2e and 3e.

  By sealing the gap 4v, the adhesive 4 does not overflow the transmission optical surfaces 2a, 2b; 3a, 3b through which the reproduction video light L2 and the external light L3 are transmitted. There is no decline. Since the operation of removing the adhesive 4 overflowing the transmission optical surfaces 2a, 2b; 3a, 3b is not required, the transmission optical surfaces 2a, 2b; 3a, 3b are scratched in the operation of removing the adhesive 4. There is no end to it. Further, since the bubbles 8 can be prevented from being generated in the adhesive 4 during the operation of filling the adhesive 4, it is possible to suppress the deterioration of the see-through performance of the external image and the deterioration of the image due to the bubbles 8. In addition, there is no need to complicate the prism surface shape. Therefore, it is possible to manufacture the cemented prism 1 without optical characteristic deterioration.

1 Bonding prism (bonding optical element)
2 Prism (transparent material)
2a, 2b Transmission optical surface 2c, 2d Side surface 2e Bonding optical surface 3 Prism (transparent member)
3a, 3b Transmission optical surface 3c, 3d Side surface 3e Bonding optical surface 4 Adhesive 4v Gap 5 Hologram member (optical function member)
5a Equal width portion 5b Narrow width portion 7 Air 8 Bubble 9 Display element 10 Video display device 11 Prism mounting portion 12 Upper sealing portion 12a Upper sealing member 12b Spring 13 Lower sealing portion 13a Lower sealing member 13b Spring 14 Side seal Stop 14a Side seal member 14b Shutter 14h Open 15 Side seal 15a Side seal 15b Shutter 15h Open 16 Air suction part 16a Suction pump 16b Pressure gauge 17 Adhesive injection part 17a Syringe 17b Pressure system 18 Light source part 18a UV light source moving system 18b Slider 19 Prism position adjusting mechanism 19a Clamp 19b Micro head 20 Flow rate adjusting mechanism 21 Flow rate adjusting mechanism 21a Valve 22 Sheet member 22h Opening x1 to x3, y1 to y3 Positioning member X1 to X3, Y1 to Y3 Reference surface U1 ~ U3 pre Beam welding device L1 image light L2 reproduction image light L3 external light EY observer's eye

Claims (9)

An optical functional member that optically acts on the light guided by the transparent member is positioned between two transparent members each having a transmission optical surface through which light is transmitted, and the optical functional member is interposed therebetween. A method of manufacturing a bonded optical element having a structure in which the two transparent members are bonded with an adhesive,
A step of fixing the two transparent members at regular intervals so that the two transparent members face each other on the optical functional member side and the transmissive optical surfaces are continuously located on both sides; When,
Sealing the gap between the two transparent members on both sides of the transmission optical surface;
Sealing each of the gaps between the two transparent members on both sides of the side surface that is perpendicular to the transmission optical surface and on which the image light and external light are not incident; and
Sucking out the air in the gap between the two transparent members from the one sealing member sealing the side surface;
Injecting the adhesive into the gap between the two transparent members from the other sealing member sealing the side surface;
Curing the adhesive injected into the gap and joining the two transparent members;
The manufacturing method characterized by having.   The manufacturing method according to claim 1, wherein at least one of air flow rate control in the step of sucking out air and adhesive flow rate control in the step of injecting the adhesive is performed.   3. The manufacturing method according to claim 1, wherein the adhesive is pressurized in the step of injecting the adhesive.   The said adhesive agent is a photocurable adhesive agent, The irradiation position of the light which hardens the said adhesive agent is moved from the position which sucks out the said air to the position which inject | pours the said adhesive agent, The 1-3 characterized by the above-mentioned. The manufacturing method of any one of these.   5. The manufacturing method according to claim 1, wherein in the step of fixing the two transparent members, a relative position of the other transparent member with respect to the one transparent member is adjusted.   In the step of sealing the gaps between the two transparent members on both sides of the side surface with a sealing member, the connection between the two transparent members and the sealing member sealing the side surface is hot. The manufacturing method according to any one of claims 1 to 5, wherein a sheet member made of a melt adhesive is used.   In the step of sealing the gaps between the two transparent members on both sides of the side surfaces with a sealing member, silicone is used for connection between the two transparent members and the sealing member sealing the side surfaces. The manufacturing method according to claim 1, wherein a sheet member made of a system gel rubber material is used.   The manufacturing method according to claim 1, wherein the optical function member is a hologram member.   The manufacturing method according to any one of claims 1 to 8, wherein the optical function member has a shape in which a width is narrowed toward an end on each of the air suction side and the adhesive injection side. .

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