JP2007093945A - Optical coupler and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical coupler in which the increase in the cost of components necessary for the optical coupler is suppressed as far as possible, upsizing is prevented and the influence of chromatic aberration is reduced, and to provide an image display apparatus. <P>SOLUTION: Used optical coupling collimator lenses 13, 13 and 13 have a same focal length, the distances d between the optical coupling collimator lenses 13, 13 and 13 and the emitting end positions of optical coupling optical fibers 8, 8 and 8 are set in such a way that the distance d1 related to R-luminous flux is equal to the focal length of the optical coupling collimator lens 13, and the distance d2 related to G-luminous flux is a prescribed distance longer than the distance d1, and the distance d3 related to B-luminous flux is a prescribed distance longer than the distance d2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical coupler that optically couples a plurality of light beams having different wavelengths to an optical transmission unit, and an image display device that displays an image by emitting the light beam combined by the optical coupler from the optical transmission unit. .

  R (red), G (green), and B (blue) light beams that are individually emitted from a light source are combined into an optical fiber by an optical coupler that incorporates the R light beam, the G light beam, and the B light beam. 2. Description of the Related Art An image display device that displays an image by scanning a light beam emitted from a horizontal direction and a vertical direction has been developed (see, for example, Patent Document 1).

  In the optical coupler of such an image display device, light of the corresponding wavelength is reflected on the optical paths of the R light beam, G light beam, and B light beam incident from the light source, but light of other wavelengths is transmitted. The dichroic mirror is arranged so that the optical path of the reflected light from each dichroic mirror is superimposed on one axis, and each reflected light from each dichroic mirror is superimposed on one axis, The light is condensed by a condensing lens and incidently coupled into the optical fiber.

JP 2005-84348 A

  However, in such a conventional optical coupler, since the superimposed light superimposed on one axis by each dichroic mirror is condensed by one condenser lens, the R light flux component constituting the superimposed light, There has been a problem that the influence of the chromatic aberration of the G beam component and the B beam component is large. On the other hand, although superimposed light can be condensed while reducing chromatic aberration using a plurality of lenses, there is a problem that the optical coupler is increased in size in addition to the increase in the component cost.

  The present invention has been made in view of such circumstances, and suppresses an increase in the component cost required for the optical coupler as much as possible, while avoiding an increase in size and reducing the influence of chromatic aberration. An optical coupler that can be used, and an image display device including the optical coupler are provided.

  According to the first aspect of the present invention, a plurality of collimating lenses into which light beams having different wavelengths are respectively incident from a plurality of predetermined emission positions and the light beams emitted from the collimating lenses are superimposed on one axis. In an optical coupler that includes an optical unit and a condensing unit that collects the superimposed light beam superimposed by the optical unit and causes the light beam to enter the optical transmission unit, and optically couples the light beam to the optical transmission unit. The condensing unit is configured by using one condensing lens, and among the components of the light beams constituting the superimposed light beam, each component incident on the light transmission unit has a required ratio. It is configured as described above.

  According to the second aspect of the present invention, the wavefront curvature of each component incident on the condenser lens is larger when the wavefront curvature is related to a relatively long wavelength component than when the wavefront curvature is related to a relatively short wavelength component. It is characterized by the above.

  According to a third aspect of the present invention, the focal lengths of the respective collimating lenses are substantially equal to each other, and the distance between each of the emission positions and the corresponding collimating lens relates to a light beam having a relatively long wavelength. It is characterized in that the case of a light beam having a shorter wavelength is shorter.

  In the present invention according to claim 4, the diameter of the light beam related to each of the components incident on the condenser lens is smaller in the diameter related to a relatively short wavelength than that related to a relatively long wavelength. It is characterized by that.

  In the present invention according to claim 5, the focal length of each collimating lens is shorter when a light beam with a relatively short wavelength is incident than when a light beam with a relatively long wavelength is incident, The distance between each emission position and each collimating lens is the focal length of the collimating lens.

  According to the sixth aspect of the present invention, the light diameter adjusting means for making the light diameter on the exit side smaller than the light diameter on the entrance side is disposed on the exit side optical path of the collimator lens on which a light beam having a relatively short wavelength is incident. It is characterized by being.

  The present invention according to claim 7 is characterized in that the light diameter adjusting means is configured to be adjustable to a plurality of different light diameters.

  The present invention according to claim 8 is characterized in that a light diffractive portion for reducing chromatic aberration of each component is provided in the condenser lens.

  The present invention according to claim 9 is characterized in that a ratio of each component incident in the optical transmission means is determined so that a ratio of a component having low visibility is increased.

  According to the tenth aspect of the present invention, at least three collimating lenses are arranged, and the ratio of each component incident in the optical transmission means is such that the ratio of the component related to the light beam having an intermediate wavelength is high. It is characterized by being defined.

  The present invention according to claim 11 is characterized in that the optical means includes one or a plurality of dichroic mirrors.

  The present invention according to claim 12 includes a plurality of light sources that respectively emit light beams having different wavelengths, a plurality of collimator lenses that receive light beams emitted from the light sources separately from a plurality of predetermined emission positions, Optical means for superimposing the light beams emitted from the collimator lens on one axis, an optical coupler for condensing the superimposed light beams superimposed by the optical means, and the condensing of the optical coupler And an optical transmission unit that optically couples the superposed light beam collected by the optical unit, and two-dimensionally scans the light beam emitted from the light transmission unit to display an image. It is comprised using the optical coupler of any one of Claim 1 to 11 as a coupler.

  The present invention according to claim 13 is characterized by comprising relay optical means for irradiating the retina with a two-dimensionally scanned light beam, and an image is displayed on the retina by this relay optical means.

  In the present invention according to claim 1, claim 11, claim 12 or claim 13, a plurality of collimating lenses into which light beams having different wavelengths respectively enter from a plurality of predetermined emission positions, and each collimating lens Optical means such as one or a plurality of dichroic mirrors that superimpose each light beam emitted from the optical axis, and a condensing unit that condenses the superimposed light beams superimposed by the optical means and enters the light transmission means. When the light beams are optically coupled to the light transmission means, the condensing unit is configured by using a single condensing lens, and the light among the components of the light beams constituting the superimposed light beam Since each component incident on the transmission means is configured to have a required ratio, an increase in the cost of components required for the optical coupler is suppressed as much as possible while avoiding an increase in size. , Color yield It is possible to reduce the impact.

  In the present invention of claim 2, claim 11, claim 12, or claim 13, the wavefront curvature of each of the components incident on the condenser lens is relatively more than that associated with a component having a relatively short wavelength. Since the long wavelength component is larger, the focal length of the relatively long wavelength component condenser lens and the focal length of the relatively short wavelength component condenser lens are approximately They can be the same, thereby reducing the effects of chromatic aberration.

  Here, the wavefront curvature is used in agreement with the wavefront curvature radius. That is, the parallel light has an infinite wavefront curvature (radius), and the convergent light whose degree of convergence is nearly parallel has a larger wavefront curvature (radius).

  In the present invention of claim 3, claim 11, claim 12, or claim 13, the focal lengths of the collimating lenses are substantially equal to each other, and the distance between each of the emission positions and the corresponding collimating lens is The wavefront curvature of each of the components incident on the condenser lens is relatively short because the case where the light beam has a relatively short wavelength is shorter than the case where the light beam has a relatively long wavelength. It is possible to increase the size of the component related to the wavelength component relatively longer than that related to the wavelength component, and to reduce the influence of chromatic aberration as before. Further, since it is only necessary to determine the distance between each emission position and the corresponding collimating lens as described above, it is possible to suppress the increase in the cost of components required for the optical coupler as much as possible, and to increase the size. Can be avoided.

  In the present invention according to claim 4, claim 11, claim 12, or claim 13, the diameter of the light flux related to each component incident on the condenser lens is relatively larger than that related to a relatively long wavelength. Since the wavelength related to the short wavelength is made smaller, the distance in the optical axis direction of the convergence region by the condensing lens of the component having a relatively short wavelength can be increased. It can enter into the means. Therefore, the influence of chromatic aberration can be reduced.

  In the present invention according to claim 5, claim 11, claim 12, or claim 13, each collimator lens has a focal length of a light beam having a shorter wavelength than a light beam having a relatively long wavelength incident thereon. The incident light is shorter, and the distance between each emission position and each collimating lens is the focal length of the collimating lens, so that the diameter of the light beam related to each component incident on the condenser lens. Can be made smaller for those with relatively short wavelengths than for those with relatively long wavelengths, thereby reducing the effects of chromatic aberration as before. Moreover, since it is only necessary to arrange collimating lenses having different focal lengths, an increase in the component cost required for the optical coupler can be suppressed as much as possible, and an increase in size can be avoided.

  In the present invention according to claim 6, claim 11, claim 12 or claim 13, on the exit side optical path of the collimating lens into which a light beam having a relatively short wavelength is incident, the exit side is closer to the exit side. Since the light diameter adjusting means for reducing the light diameter is provided, the diameter of the light beam related to each component incident on the condenser lens is related to a relatively short wavelength than that related to a relatively long wavelength. The fiber can be made smaller, and the difference in the NA of the optical fiber depending on the wavelength can be corrected. On the other hand, the light diameter adjusting means can be configured by, for example, penetrating a hole having a required diameter through a light-shielding thin plate material, thereby suppressing as much as possible the increase in the component cost required for the optical coupler. In addition to being able to do so, an increase in size can be avoided.

  In the present invention according to claim 7, claim 11, claim 12 or claim 13, the light diameter adjusting means is configured to be adjustable to a plurality of different light diameters, so that there are variations in products such as light sources. Even if it exists, by adjusting to the required light diameter by the light diameter adjusting means, it is possible to reduce as much as possible the influence that the NA of the optical fiber varies depending on the wavelength.

  In the present invention according to claim 8, claim 11, claim 12 or claim 13, since the light diffractive portion for reducing the chromatic aberration of each component is provided in the condenser lens, the enlargement is avoided. The influence of chromatic aberration can be reduced.

  In the present invention according to claim 9, claim 11, claim 12 or claim 13, the proportion of each component incident on the optical transmission means is determined such that the proportion of the component having low visibility is increased. Therefore, the color balance when visually recognized is improved, whereby the influence of chromatic aberration can be reduced. Moreover, since it is only necessary to adjust the ratio of each component, an increase in the cost of components required for the optical coupler can be suppressed as much as possible, and an increase in size can be avoided.

  In the present invention according to claim 10, claim 11, claim 12, or claim 13, at least three collimating lenses are arranged, and the proportion of each component incident in the optical transmission means is an intermediate wavelength. Since the ratio of the component related to the light flux of the light source is determined to be high, the component related to the light flux of the different wavelength can be balanced by the component related to the light flux of the intermediate wavelength, thereby reducing the influence of chromatic aberration. Can do. Moreover, since it is only necessary to adjust the ratio of each component, an increase in the cost of components required for the optical coupler can be suppressed as much as possible, and an increase in size can be avoided.

  The optical coupler according to the present invention superimposes a plurality of collimating lenses on which light beams having different wavelengths are respectively incident from a plurality of predetermined emission positions and the light beams emitted from the collimating lenses on one axis. In an optical coupler that includes an optical unit and a condensing unit that collects the superimposed light beam superimposed by the optical unit and causes the light beam to enter the optical transmission unit, and optically couples the light beam to the optical transmission unit. The condensing unit is configured by using one condensing lens, and among the components of the light beams constituting the superimposed light beam, each component incident on the light transmission unit has a required ratio. It is constituted as follows.

  The wavefront curvature of each of the components incident on the condensing lens described above is larger for the component related to the relatively long wavelength component than for the component related to the relatively short wavelength component.

  On the other hand, the focal lengths of the respective collimating lenses are substantially equal to each other, and the distance between each of the emission positions and the corresponding collimating lens is a light beam having a relatively short wavelength compared to the case of a light beam having a relatively long wavelength. The case where it concerns is shortened.

  In addition, the diameter of the light beam related to each of the components incident on the condenser lens is made smaller for a light beam having a relatively short wavelength than that for a light wave having a relatively long wavelength.

  Specifically, the focal length of each collimating lens is shorter when a relatively short wavelength light beam is incident than when a relatively long wavelength light beam is incident. The distance from each collimating lens is the focal length of the collimating lens.

  Further, a light diameter adjusting means for making the light diameter on the outgoing side smaller than the light diameter on the incoming side may be disposed on the outgoing optical path of the collimating lens on which a light beam having a relatively short wavelength is incident.

  The light diameter adjusting means may be configured to be adjustable to a plurality of different light diameters.

  On the other hand, the condensing lens is provided with a light diffractive portion for reducing the chromatic aberration of each component.

  By the way, the ratio of each component incident in the optical transmission means is determined so that the ratio of the component having low visibility is increased.

  In addition, at least three collimating lenses may be arranged, and the ratio of each component incident in the optical transmission unit may be determined so that the ratio of the component related to the light beam having an intermediate wavelength is high.

  Here, the optical means includes one or a plurality of dichroic mirrors.

  An image display device according to the present invention includes a plurality of light sources that emit light beams having different wavelengths, a plurality of collimator lenses that receive light beams emitted from the light sources separately from a plurality of predetermined emission positions, Optical means for superimposing the light beams emitted from the collimator lens on one axis, an optical coupler for condensing the superimposed light beams superimposed by the optical means, and the condensing of the optical coupler And an optical transmission unit that optically couples the superposed light beam collected by the optical unit, and two-dimensionally scans the light beam emitted from the light transmission unit to display an image. As a coupler, any one of the optical couplers described above is used.

In addition, a relay optical unit that irradiates the retina with a two-dimensionally scanned light beam is provided, and an image is displayed on the retina by the relay optical unit, thereby being applied as a retina scanning type image display device.
(Embodiment 1)

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration of a retinal operation type image display apparatus according to the present invention together with a block diagram. In FIG. 1, reference numeral 1 denotes a video signal supply for supplying required video signals to a plurality of drivers described later. Circuit.

  A video signal is supplied to the video signal supply circuit 1 from the outside, and the video signal supply circuit 1 performs wavefront curvature modulation, which will be described later, based on the supplied video signal so as to give a depth to an image to be displayed. A depth signal for controlling the operation of the driver 70, a horizontal synchronization signal for performing horizontal synchronization when performing two-dimensional scanning, and a vertical synchronization signal for performing vertical synchronization when performing two-dimensional scanning are generated. The depth signal is supplied to the wavefront curvature modulation driver 70, the horizontal synchronization signal is supplied to the horizontal scanning driver 71, and the vertical synchronization signal is supplied to the vertical scanning driver 74.

  Further, the video signal supply circuit 1 controls the R video signal, the G video signal, and the B video for adjusting the light amounts of the R (red) light beam, the G (green) light beam, and the B (blue) light beam based on the video signal. The R video signal, the G video signal, and the B video signal are separately supplied to the corresponding R laser driver 3, G laser driver 4, and B laser driver 2, respectively.

  Each of these laser drivers 3, 4, 2 controls the output of the corresponding R laser emitter 6, G laser emitter 7, and B laser emitter 5 according to the given video signal, and the light quantity of each emitted laser beam. Adjust. Each laser beam emitted from each of the laser emitters 6, 7, and 5 is transmitted to the optical coupler 10 through the three optical coupling optical fibers shown in FIG.

  In the optical coupler 10, three optical coupling collimating lenses 13, 13, 13 that emit incident light in parallel are arranged in a line, and each optical coupling optical fiber is connected to the optical coupler 10. The end portions are coupled so as to face the corresponding optical coupling collimating lenses 13, 13, 13. The laser beam emitted from the exit end of each optical coupling optical fiber is converted into parallel light while passing through the corresponding optical coupling collimator lenses 13, 13, 13. Inside the optical coupler 10, dichroic mirrors 21, 22, and 23 that reflect light of a predetermined wavelength and transmit light of other wavelengths are respectively connected to the optical coupling collimator lenses 13, 13, and 13 respectively. Are arranged on one axis so as to face each other, and each laser beam made into parallel light is dichroic mirrors 21, 22 and 23 corresponding to the B laser emitter 5, the R laser emitter 6 and the G laser emitter 7. They are turned in the uniaxial direction and are superposed (combined) with each other.

  A condensing lens 32 constituting a condensing unit is disposed on the one axis, and the optical coupler 10 faces the condensing lens 32 and is incident on an incident end of a scanning optical fiber (optical transmission means) 40. Are connected. Then, the superposed light beam superimposed as described above is condensed by the condensing lens 32 and is incidentally coupled into the scanning optical fiber 40.

  The light beam optically coupled to the scanning optical fiber 40 is transmitted to a predetermined position by the scanning optical fiber 40. A scanning collimator lens 50 is disposed opposite to the exit end of the scanning optical fiber 40, and the light beam emitted from the exit end of the scanning optical fiber 40 is again converted into parallel light by the scanning collimator lens 50. The light is incident on the beam splitter 61 of the wavefront modulation unit 60, where it is separated into transmitted light and reflected light reflected in a direction orthogonal to the transmitted light.

  The reflected light is converged on the movable mirror 63 by the convex lens 62 and reflected by the movable mirror 63 in the direction opposite to the incident direction. The movable mirror 63 is driven forward and backward by the wavefront curvature modulation driver 70 toward the convex lens 62 or away from the convex lens 62. The wavefront curvature modulation driver 70 is the video signal supply circuit 1 described above. The wavefront curvature of the reflected light is modulated by moving the movable mirror 63 back and forth in accordance with the depth signal given from.

  Reflected light from the movable mirror 63 passes through the convex lens 62 and the beam splitter 61 and is incident on the horizontal scanning mirror 72. The horizontal scanning mirror 72 is rotatably supported around a support shaft that supports the horizontal scanning mirror 72, and is controlled to rotate by a horizontal scanning driver 71. The horizontal scanning driver 71 is supplied with a horizontal synchronizing signal from the video signal supply circuit 1 described above, and the horizontal scanning driver 71 rotates the horizontal scanning mirror 72 according to the given horizontal synchronizing signal. Thus, the light beam whose wavefront curvature is modulated is horizontally scanned.

  The light beam horizontally scanned in this way is incident on the vertical scanning mirror 75 by the first relay optical means 73 provided with a plurality of lenses. The vertical scanning mirror 75 is rotatably supported around a support shaft that supports the vertical scanning mirror 75, and is controlled to rotate by a vertical scanning driver 74. The vertical scanning driver 74 is supplied with a vertical synchronizing signal from the video signal supply circuit 1 described above, and the vertical scanning driver 74 rotates the vertical scanning mirror 75 in accordance with the supplied vertical synchronizing signal. Thus, the horizontally scanned light beam is vertically scanned.

  The light beam that has been two-dimensionally scanned by the horizontal scanning mirror 72 and the vertical scanning mirror 75 in this way is projected into the eyeball I by the second relay optical means 76 having a plurality of lenses disposed on the internal retina. An image is displayed.

  FIG. 2 is a schematic enlarged sectional view showing the optical coupler 10 shown in FIG. In the figure, the same reference numerals are given to the portions corresponding to the portions shown in FIG. As shown in FIG. 2, the optical coupler 10 includes a casing 11 formed of a light-shielding member, for example, in the shape of a rectangular shell, and is the side surface of the casing 11 and the central axis of the casing 11. Three through-holes are opened at a predetermined distance from one end of the housing 11 on a line segment that is parallel to the line 11. On the side surface of the housing 11 and around each through hole, connecting portions 12, 12, and 12 formed in a cap shape with a light-shielding member are fixed, and external light into each through hole is fixed. Intrusion is prevented.

  The optical coupling collimating lenses 13, 13, 13 are arranged in each of the coupling parts 12, 12, 12 so that the optical axis thereof is parallel to the central axis of the coupling parts 12, 12, 12. The B light fluxes emitted from the B laser emitter 5, the R laser emitter 6 and the G laser emitter 7 described above are located at positions on the optical axis of the ceiling portions of the connecting portions 12, 12, and 12, respectively. The output side end portions of the optical coupling optical fibers 8, 8, 8 to which the light beam and the G light beam are separately incident are inserted into the connecting portions 12, 12, 12 by a predetermined size in the housing. They are connected in this order from one end of the body 11. The R light beam, the G light beam, and the B light beam transmitted by the optical coupling optical fibers 8, 8, 8 are collimated lenses 13, 13, 13 in the coupling portions 12, 12, 12 from the respective emission side ends. 13, passes through the optical coupling collimating lenses 13, 13, and 13 and enters the housing 11 through the through holes.

  The dichroic mirrors 21, 22, and 23 described above are arranged in a line on an axis parallel to the central axis of the housing 11 on the optical path of each incident light beam in the housing 11. The corresponding dichroic mirrors 21, 22, and 23 are reflected at right angles to one end side of the housing 11, and these reflected light beams are all superimposed (combined) between one end of the housing 11 and the dichroic mirror 21 facing the one end. Waves).

  An exit through-hole is formed at one end surface of the housing 11 and on the axis, and a cap-like shape is formed around the through-hole of the housing 11 with a light shielding member. The connecting portion 30 is fixed so as to prevent external light from entering the through hole. In this connecting portion 31, one condensing lens 32 is disposed with its optical axis coinciding with the axis, and the condensing portion 30 is constituted by the condensing lens 32 and the connecting portion 31. . The incident end portion of the scanning optical fiber 40 is connected to the position on the axis of the ceiling surface of the coupling portion 31 in such a manner that the end portion is inserted into the interior by a predetermined dimension, and the dichroic mirror is connected. The superposed light beam that has been superposed at 21, 22, and 23 and collected by the condensing lens 32 enters the scanning optical fiber 40 and is optically coupled to the inner core.

  In the optical coupler 10 according to the present embodiment, the influence of chromatic aberration is reduced as follows.

  FIG. 3 is a partially enlarged view of the optical coupling collimating lenses 13, 13, 13 and the optical coupling optical fibers 8, 8, 8 shown in FIG. 2, and adjusts the wavefront curvature of the incident light beam to the optical coupler. The configuration will be described. FIG. 4 is a schematic partial enlarged cross-sectional view of the condenser lens 32 and the scanning optical fiber 40 shown in FIG. 2. The R light beam, G light beam, and B light beam with adjusted wavefront curvature are scanned optical fibers. In FIG. In both figures, the solid line indicates the R light beam, the alternate long and short dash line indicates the G light beam, and the broken line indicates the B light beam. In both figures, the same reference numerals are given to the portions corresponding to the portions shown in FIG.

  As shown in FIG. 3, the optical coupling collimating lenses 13, 13, and 13 have the same focal length, and the optical coupling collimating lenses 13, 13, and 13 and the optical coupling optical fibers 8, 8, and 8 are used. The distance d to the emission position as the end of the light beam is the focal length of the collimating lens 13 for optical coupling for the distance d1 related to the R light beam, and the distance d1 for the distance d2 related to the G light beam. The predetermined distance is longer, and the distance d3 related to the B light flux is set to a predetermined distance longer than the distance d2.

  In this case, the R light beam is converted into parallel light by the corresponding optical coupling collimating lens 13, the wavefront curvature of the G light beam is made smaller than that of the parallel light, and the wavefront curvature of the B light beam is made smaller than the wavefront curvature of the G light beam. As a result, as shown in FIG. 4, the convergence position of the R light beam by the condenser lens 32, the convergence position of the G light beam, and the convergence position of the B light beam become substantially the same, and the influence of chromatic aberration by the condenser lens 32 is reduced. can do.

Further, since the distance between each optical coupling collimating lens 13, 13, 13 and the end of the optical coupling optical fiber 8, 8, 8 has only to be determined as described above, the component cost required for the optical coupler 10 is reduced. Increase of the optical coupler 10 can be suppressed as much as possible, and an increase in the size of the optical coupler 10 can be avoided.
(Embodiment 2)

  FIG. 5 is a schematic cross-sectional view showing a configuration of a main part of the optical coupler according to the second embodiment. By adjusting the diameters (light diameters) of the R light beam, the G light beam, and the B light beam, the optical fiber is changed depending on the wavelength. The effect of different NAs is reduced. 6 is a schematic partial enlarged cross-sectional view of the condensing lens 32 and the scanning optical fiber 40 shown in FIG. 2, and the R light beam, G light beam, and B light beam whose light diameters are adjusted are the scanning optical fiber. In FIG. In these figures, portions corresponding to those shown in FIG. 2 are given the same numbers, the solid line indicates the R light beam, the alternate long and short dash line indicates the G light beam, and the broken line indicates the B light beam. .

  As shown in FIG. 5, the focal length f of each of the optical coupling collimating lenses 13, 13, and 13 is longer in the focal length f2 related to the G light flux than the focal length f1 related to the B light flux, and the focal length related to the G light flux. The focal length f3 related to the R light flux is longer than f2. The emission position as the end of each optical coupling optical fiber 8, 8, 8 is the position of the focal length of the corresponding optical coupling collimator lens 13, 13, 13.

  In this case, as shown in FIG. 5, the luminous flux emitted from the optical coupling collimating lenses 13, 13, and 13 has a larger diameter of the G luminous flux than the diameter of the B luminous flux, and the diameter of the R luminous flux than the diameter of the G luminous flux. Big of. Accordingly, as shown in FIG. 6, each of the light beams incident on the condenser lens 32 is similarly larger in diameter of the G light beam than in the B light beam and larger in diameter of the R light beam than the diameter of the G light beam. .

  FIG. 16 is a schematic cross-sectional view showing the main part of a conventional optical coupler, in which the R, G, and B light beams having the same diameter are optically coupled to the scanning optical fiber 140 by the condensing lens 132. Indicates the state. As shown in FIG. 16, when the R, G, and B light beams having the same diameter are incident on the condenser lens 132, the converging lenses are arranged in the order of the B light beam, the G light beam, and the R light beam. Chromatic aberration occurred at a distance from the chromatic aberration. Accordingly, when the amount of coupling of the R beam is optically coupled to the scanning optical fiber 140 is maximized, the coupling amount of the G beam is lower than the coupling amount of the R beam, and the coupling amount of the B beam is G. It was lower than the combined amount of light beams.

  By the way, the convergence area where the luminous flux is converged as much as possible by the condenser lens has a distance in the axial length direction of the optical axis. The distance varies depending on the diameter of the light beam incident on the condenser lens, and the distance when the diameter of the light beam is small is longer than when the diameter of the light beam is large. In the present embodiment, as described above, each light beam incident on the condenser lens 32 has a smaller diameter of the G light beam than a diameter of the R light beam, and a smaller diameter of the B light beam than the diameter of the G light beam. Therefore, the convergence region of the B light beam, the convergence region of the G light beam, and the convergence region of the R light beam can be overlapped, thereby reducing the influence of the NA of the optical fiber depending on the wavelength as described above.

  Then, as shown in FIG. 6, the amount of optical coupling between each light beam and the scanning optical fiber 40 is increased by positioning the incident side end of the scanning optical fiber 40 in the overlapped convergence region. Can do.

Moreover, since it is only necessary to arrange the collimating lenses 13, 13, and 13 having different focal lengths at predetermined positions, an increase in the cost of components required for the optical coupler can be suppressed as much as possible, and the size is increased. Can be avoided.
(Embodiment 3)

  FIG. 7 is a schematic cross-sectional view showing the main configuration of the optical coupler according to Embodiment 3, in which the diameter of each light beam incident on the condenser lens 32 is adjusted. In the figure, parts corresponding to those shown in FIG.

  As shown in FIG. 7, between the collimating lenses 13, 13, 13 and the dichroic mirrors 21, 22, 23, for example, a hole having a diameter smaller than the diameter of the incident light beam is formed in the light shielding member, and the corresponding light beam. The light diameter adjusting units 25, 25, 25 for adjusting the diameter of the light beam are interposed, and each light beam emitted from the collimating lenses 13, 13, 13 is converted into an R light beam by the light diameter adjusting unit 25, 25, 25. The diameter of the G light beam is smaller than the diameter, and the diameter of the B light beam is made smaller than the diameter of the G light beam so as to be incident on the dichroic mirrors 21, 22, and 23.

  FIGS. 8 to 13 are schematic views showing a configuration example of the light diameter adjusting unit 25 shown in FIG. 7, and can be changed to a plurality of light diameters. That is, as shown in FIGS. 8 and 9, the light diameter adjusting unit 25a has a light-shielding disc with a plurality of through holes (four in both drawings) having different diameters in the circumferential direction. Opened at intervals, any through-hole can be rotatably supported so that it can be positioned on the optical path from the collimating lens 13 to the dichroic mirror 21 (22, 23) shown in FIG. .

  Further, as shown in FIGS. 10 and 11, the light diameter adjusting portion 25b is formed by arranging a plurality of through holes having different diameters (three in both drawings) on the light shielding rectangular plate at a constant interval in the longitudinal direction. It is also possible to configure such that any one of the through holes can be moved back and forth so that any of the through holes can be positioned on the optical path from the collimating lens 13 to the dichroic mirror 21 (22, 23) shown in FIG.

  Further, as shown in FIGS. 12 and 13, the light diameter adjusting unit 25c arranges a variable aperture or a liquid crystal (LCD) shutter on the optical path from the collimating lens 13 to the dichroic mirror 21 (22, 23), so that the light flux You may comprise so that the diameter of the permeation | transmission area | region can be changed on a concentric circle.

  As a result, each of the light beams incident on the condenser lens 32 can have a smaller diameter of the G light beam than a diameter of the R light beam and a smaller diameter of the B light beam than the diameter of the G light beam. The convergence region of the B light beam, the convergence region of the G light beam, and the convergence region of the R light beam can be overlapped, and the difference due to the wavelength can be reduced.

  Further, since the light diameter adjusting units 25, 25, 25 can be adjusted to different light diameters as described above, for example, the R laser emitter 6, the G laser emitter 7, and the B laser emitter shown in FIG. Even if there is a variation in 5, the variation can be reduced by changing the diameter of the through hole or the diameter of the transmission region of the corresponding light diameter adjusting unit 25.

  In addition, since the light diameter can be adjusted with a relatively simple configuration, an increase in the component cost required for the optical coupler 10 can be suppressed as much as possible.

In the present embodiment, the light diameter adjusting units 25, 25, 25 can be adjusted to different light diameters, but the present invention is not limited to this, and may be adjusted to one appropriate light diameter. Needless to say, it is good.
(Embodiment 4)

  FIG. 14 is a schematic cross-sectional view showing the main configuration of the optical coupler 10 according to Embodiment 4, in which chromatic aberration is reduced by light diffraction. In the figure, parts corresponding to those in FIG.

As shown in FIG. 14, a light diffractive portion 33 formed by engraving a light diffraction grating is formed on the exit side surface of the condensing lens 32a. The converging position of B and the converging position of the B light beam are substantially matched. Accordingly, chromatic aberration can be reduced while avoiding an increase in size, and the R light beam, the G light beam, and the B light beam can be incident on the scanning optical fiber 40 substantially evenly.
(Embodiment 5)

  FIG. 15 is a schematic cross-sectional view showing the configuration of the main part of the optical coupler 10 according to the fifth embodiment, in which the color balance when a human visually recognizes is adjusted. In the figure, parts corresponding to those shown in FIG. 4 are denoted by the same reference numerals and description thereof is omitted. The solid line indicates the R light beam, the alternate long and short dash line indicates the G light beam, and the broken line indicates the B light beam.

  As shown in FIG. 15, in the optical coupler 10 according to the present embodiment, the distance between the condensing lens 32 and the scanning optical fiber 40 is the B light flux indicated by the broken line from the condensing lens 32. Is the distance to the position where is converged. In this case, the amount of coupling of the R light beam, the G light beam, and the B light beam collected by the condensing lens 32 with the scanning optical fiber 40 is the largest for the B light beam, and is the smallest in the order of the G light beam and the R light beam. .

  By the way, the visual sensitivity indicating the degree to which a human can perceive light beams of various colors is the highest in the G light beam and the lowest in the B light beam among the R light beam, the G light beam, and the B light beam. . Therefore, as described above, the configuration is such that the coupling amount of the B light beam having a low visibility is increased and the coupling amount of the G light beam having a high visibility is decreased, thereby improving the color balance when visually recognized. Thus, the influence of chromatic aberration can be reduced.

  Further, since it is only necessary to set the distance between the condensing lens 32 and the scanning optical fiber 40 to a required dimension, an increase in the component cost required for the optical coupler 10 can be suppressed as much as possible. In addition, an increase in size can be avoided.

  In each of the above-described embodiments, the retinal scanning type image display device has been described. However, the present invention is not limited to this, and can be applied to, for example, an image display device that displays an image on a wall surface or the like at an event venue. Needless to say.

1 is a schematic diagram showing a configuration of a retina operation type image display device according to the present invention together with a block diagram. It is a typical expanded sectional view which shows the optical coupler shown in FIG. FIG. 3 is a partially enlarged view of the optical coupling collimator lens and the optical coupling optical fiber illustrated in FIG. 2. It is a typical partial expanded sectional view of the condensing lens and scanning optical fiber shown in FIG. FIG. 5 is a schematic cross-sectional view showing a main part configuration of an optical coupler according to Embodiment 2. It is a typical partial expanded sectional view of the condensing lens and scanning optical fiber shown in FIG. FIG. 5 is a schematic cross-sectional view showing a main part configuration of an optical coupler according to Embodiment 3. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. It is a schematic diagram which shows the structural example of the light diameter adjustment part shown in FIG. FIG. 6 is a schematic cross-sectional view showing a main part configuration of an optical coupler according to Embodiment 4. FIG. 9 is a schematic cross-sectional view showing a main part configuration of an optical coupler according to Embodiment 5. It is typical sectional drawing which shows the principal part of the conventional optical coupler.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 B laser driver 3 R laser driver 4 G laser driver 5 B laser emitter 6 R laser emitter 7 G laser emitter 8 Optical fiber for optical coupling 10 Optical coupler 11 Case 12 Connecting part 13 Optical coupling Collimating lens 21 Dichroic mirror 22 Dichroic mirror 23 Dichroic mirror 30 Condensing unit 31 Connecting unit 32 Condensing lens 32a Condensing lens 33 Optical diffracting unit 40 Scanning optical fiber 50 Scanning collimating lens 60 Wavefront modulation unit 61 Beam splitter 62 Convex lens 63 movable mirror 70 wavefront curvature modulation driver 71 horizontal scanning driver 72 horizontal scanning mirror 73 first relay optical means 74 vertical scanning driver 75 vertical scanning mirror 76 second relay optical means 132 condensing lens 140 scanning optical fiber Eyeball

Claims (13)

A plurality of collimating lenses each receiving a light beam having a different wavelength from a plurality of predetermined emission positions, an optical means for superimposing each light flux emitted from each collimating lens on one axis, and superimposing by this optical means A light condensing unit for condensing the incident superimposed light flux and entering the light transmission means, and an optical coupler for optically coupling each light flux to the light transmission means,
The condensing unit is configured using one condensing lens,
An optical coupler characterized in that, among the components of the light beams constituting the superimposed light beam, each component incident on the light transmission means has a required ratio.   2. The wavefront curvature of each of the components incident on the condensing lens is such that a component related to a relatively long wavelength component is larger than a component related to a relatively short wavelength component. Optical coupler.   The focal lengths of the respective collimating lenses are substantially equal to each other, and the distance between each of the emission positions and the corresponding collimating lens is a light beam having a relatively shorter wavelength than in the case of a light beam having a relatively long wavelength. 3. An optical coupler according to claim 2, wherein said case is shortened.   The optical coupler according to claim 1, wherein the diameter of the light flux related to each of the components incident on the condenser lens is smaller in the diameter related to the shorter wavelength than that related to the longer wavelength.   The focal length of each collimating lens is shorter when a light beam with a relatively short wavelength is incident than when a light beam with a relatively long wavelength is incident. The optical coupler according to claim 4, wherein the distance is a focal length of the collimating lens.   5. The light according to claim 4, wherein a light diameter adjusting means for making the light diameter on the exit side smaller than the light diameter on the entrance side is disposed on the exit side optical path of the collimating lens on which a light beam having a relatively short wavelength is incident. Combiner.   The optical coupler according to claim 6, wherein the light diameter adjusting means is configured to be adjustable to a plurality of different light diameters.   The optical coupler according to claim 1, wherein the condenser lens is provided with an optical diffractive portion for reducing chromatic aberration of each component.   9. The optical coupler according to claim 1, wherein a ratio of each component incident into the optical transmission unit is determined so that a ratio of a component having low visibility is increased.   9. At least three collimating lenses are arranged, and the proportion of each component incident in the optical transmission means is determined so that the proportion of the component related to the light beam having an intermediate wavelength is high. The optical coupler of any one of Claims.   The optical coupler according to claim 1, wherein the optical unit includes one or a plurality of dichroic mirrors. A plurality of light sources that emit light beams having different wavelengths, a plurality of collimating lenses that light beams emitted from the light sources respectively enter from a plurality of predetermined emission positions, and a light beam emitted from each collimating lens. An optical unit that superimposes on one axis, an optical coupler that includes a condensing unit that condenses the superimposed light beam superimposed by the optical unit, and a superimposed light beam that is collected by the condensing unit of the optical coupler In an image display device that includes an optically coupled optical transmission unit and displays an image by two-dimensionally scanning a light beam emitted from the optical transmission unit,
An image display device comprising the optical coupler according to claim 1 as the optical coupler.   13. The image display device according to claim 12, further comprising relay optical means for irradiating the retina with a two-dimensionally scanned light beam, wherein the relay optical means displays an image on the retina.

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