JP5919678B2 - Optical scanning device, image forming apparatus, and vehicle equipped with image forming apparatus - Google Patents

Description

  The present invention relates to an optical scanning device that scans a light beam emitted from a light source element to form a two-dimensional image, an image forming apparatus using the optical scanning device, and a vehicle equipped with the image forming apparatus.

  2. Description of the Related Art In recent years, there have been widely proposed optical scanning devices that obtain a color two-dimensional image by causing multi-color light beams to enter a two-dimensional scanning mirror. In particular, in an optical scanning device using a semiconductor laser as a light source, high light utilization efficiency is obtained due to the high directivity of the light beam emitted from the semiconductor laser. In addition, an optical scanning device using a semiconductor laser can emit strong light in a device without providing a huge radiator such as a xenon lamp, and in a small optical system because of its high directivity. Can also form bright images.

  An optical scanning device using a semiconductor laser may be incorporated in, for example, a passenger car and used as a head-up display. In consideration of incorporating the optical scanning device into a passenger car or the like, downsizing is inevitably required.

  However, when the miniaturization of the optical scanning device is pursued, there arises a problem that image quality and brightness are sacrificed.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical scanning device capable of realizing downsizing while ensuring the brightness and image quality of an image.

The optical scanning device includes a plurality of light source elements, a coupling lens into which light beams emitted from the plurality of light source elements respectively enter, and a combining unit that combines the light beams emitted from the plurality of coupling lenses; An incident optical system including a lens on which the light beams synthesized by the synthesizing unit are incident in common, an optical deflector that deflects the light beam emitted from the incident optical system two-dimensionally, and deflected by the optical deflector A scanning optical system comprising: a concave mirror on which the luminous flux is incident; and a scanned surface having transparency through which the luminous flux reflected by the concave mirror is incident to form a two-dimensional image, The sign of the declination due to the reflecting surface of the optical deflector and the sign of the declination due to the concave mirror are opposite to each other, and the concave mirror and the scanned surface are optical axes of light beams emitted from the incident optical system. Deviation from above It is arranged at a position, wherein the concave mirror is a requirement to be placed on the light source device side from the emission point of the light emitted from the incident optical system.

  According to the disclosed technology, it is possible to provide an optical scanning device that can be downsized while ensuring the brightness and image quality of an image.

FIG. 3 is a diagram (part 1) illustrating an optical path of the optical scanning device according to the first embodiment; FIG. 6 is a second diagram illustrating an optical path of the optical scanning device according to the first embodiment; It is a figure for demonstrating the lens. It is a figure for demonstrating arrangement | positioning of the optical deflector 16 and the concave mirror 17. FIG. It is a figure which illustrates the optical path of the optical scanning device concerning modification 1 of a 1st embodiment. It is a figure which shows the example of the image forming apparatus carrying the optical scanning device which concerns on 1st Embodiment. It is a figure which shows the other example of the image forming apparatus carrying the optical scanning device which concerns on 1st Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<First Embodiment>
FIG. 1 is a diagram (part 1) illustrating an optical path of the optical scanning device according to the first embodiment. FIG. 2 is a diagram (part 2) illustrating an optical path of the optical scanning device according to the first embodiment. 1 and 2 are views of the optical scanning device 10 viewed from different directions. However, in FIG. 2, the optical deflector 16, the concave mirror 17, and the scanned surface 18 shown in FIG. In FIGS. 1 and 2, the optical axis direction of the light source elements 11R and B is the X direction, the optical axis direction of the light source element 11G is the Z direction, and the X direction and the direction perpendicular to the Z direction are the Y direction.

  Referring to FIG. 1 and FIG. 2, the optical scanning device 10 is roughly composed of light source elements 11R, 11G, and 11B, coupling lenses 12R, 12G, and 12B, and apertures 13R, 13G, and 13B. It has an element 14, a lens 15, an optical deflector 16, a concave mirror 17, and a scanned surface 18.

  The light source elements 11R, 11G, and 11B, the coupling lenses 12R, 12G, and 12B, the apertures 13R, 13G, and 13B, the combining element 14, and the lens 15 may be collectively referred to as an incident optical system. is there. Further, the optical deflector 16, the concave mirror 17, and the scanned surface 18 may be referred to as a scanning optical system.

  In the optical scanning device 10, the light source elements 11R, 11G, and 11B can emit light beams having different wavelengths λR, λG, and λB, respectively. The wavelengths λR, λG, and λB can be set to, for example, 640 nm, 530 nm, and 445 nm, respectively. As the light source elements 11R, 11G, and 11B, for example, a laser, an LED (Light Emitting Diode), an SHG (Second Harmonic Generation) element, or the like can be used.

  From the viewpoint of realizing miniaturization while ensuring brightness and high image quality, it is preferable to use semiconductor lasers as the light source elements 11R, 11G, and 11B, respectively. The light source elements 11R, 11G, and 11B are controlled in emission power, emission timing, and the like by a control means (not shown). Note that the control means (not shown) may be provided inside the optical scanning device 10 or may be provided outside.

  Each light beam (diverging light) emitted from the light source elements 11R, 11G, and 11B according to the content of the image signal is converted into substantially parallel light or convergent light by the coupling lenses 12R, 12G, and 12B, respectively, and the aperture 13R. , 13G, and 13B. As the coupling lenses 12R, 12G, and 12B, for example, convex glass lenses, plastic lenses, and the like can be used.

  The apertures 13R, 13G, and 13B have a function of shaping a light beam incident thereon. The apertures 13R, 13G, and 13B can have various shapes such as a circle, an ellipse, a rectangle, and a square according to the divergence angle of the incident light beam.

  In addition, it is good also as a structure which provides one common coupling lens and one common aperture with respect to the light source elements 11R, 11G, and 11B. However, by providing coupling lenses 12R, 12G, and 12B and apertures 13R, 13G, and 13B to the light source elements 11R, 11G, and 11B, respectively, each of the light source elements 11R, 11G, and 11B is provided. Regardless of the difference in divergence angle, there is an advantage that the beam spot diameter on the scanned surface 18 can be adjusted to a desired value while ensuring the light use efficiency.

  The light beams shaped by the apertures 13R, 13G, and 13B are incident on the combining element 14 and are optically combined. The synthesizing element 14 is, for example, a plate-like or prism-like dichroic mirror, and has a function of reflecting or transmitting each light beam according to the wavelength and synthesizing it into one optical path.

  Each light beam combined in the optical path by the combining element 14 is guided by the lens 15 toward the reflecting surface of the optical deflector 16. As the lens 15, for example, a single meniscus lens arranged with the concave surface facing the optical deflector 16 can be used. Here, the lens 15 will be described in more detail with reference to FIG.

  FIG. 3 is a diagram for explaining the lens 15. In FIG. 3, 15 </ b> R and 15 </ b> B indicate two light beams having different wavelengths incident on the lens 15. It is preferable that the light beams 15 </ b> R and 15 </ b> B emitted from the second surface 15 b of the lens 15 are emitted in a size that fits on the reflection surface of the optical deflector 16. Since the lens 15 needs to send the light beams 15R and 15B captured by the apertures 13R and 13B as small as possible to the optical deflector 16, the first surface 15a of the lens 15 focuses the respective light beam diameters of the light beams 15R and 15B. Therefore, it is preferable that the surface is convex.

  Here, if the light beam 15R is a long wavelength light beam and the light beam 15B is a short wavelength light beam, the condensing state on the first surface 15a is different (dispersed) between the light beam 15R and the light beam 15B as shown in FIG. . If the lens 15 has another form (such as a biconvex lens or a plano-convex lens) other than the meniscus lens, the divergence angles of the emitted light beams 15R and 15B vary depending on the wavelength.

  By using a meniscus lens having the second surface 15b as a concave surface as the lens 15, the light beams 15R and 15B dispersed on the first surface 15a are refracted in the direction in which the degree of divergence is returned again on the second surface 15b. As a result, in the lens 15 into which the light beams 15R and 15B having different wavelengths are incident, the variation in the divergence degree of the emitted light beams 15R and 15B can be converged and sent to the optical deflector 16. It is possible to improve the luminance of the image without loss of image quality.

  1 and 2, the light beam emitted from the incident optical system and guided to the reflection surface of the optical deflector 16 is deflected two-dimensionally by the optical deflector 16. As the optical deflector 16, for example, one minute mirror that swings with respect to two orthogonal axes, two minute mirrors that swing or rotate with respect to one axis, and the like can be used. The optical deflector 16 can be, for example, a MEMS manufactured by a semiconductor process or the like. The optical deflector 16 can be driven by, for example, an actuator that uses the deformation force of the piezoelectric element as a driving force.

  The light beam deflected two-dimensionally by the optical deflector 16 enters the concave mirror 17 and is folded by the concave mirror 17 to draw a two-dimensional image on the scanned surface 18. It is preferable that the light beam incident on the scanned surface 18 has a close angle to the traveling direction of the light beam incident on the optical deflector 16. With such an arrangement, the distortion of the two-dimensional image on the scanned surface 18 can be reduced. Further, since the light beam enters the surface to be scanned 18 in a state of being nearly perpendicular, the transmission efficiency can be increased over a wide area in the two-dimensional image.

  By using the concave mirror 17 in the optical scanning device 10, the following effects can be obtained. First, since the concave mirror 17 does not have wavelength dispersion, color misregistration of the image on the scanned surface 18 can be reduced. Second, since the concave mirror 17 reduces the scanning angle of the light beam, the color shift of the image on the scanned surface 18 can be reduced. Third, the incident angle of the scanned surface 18 can be reduced at all scanning angles, and the luminance of the scanned surface 18 can be increased. Here, the color misregistration refers to the misregistration of a plurality of spots formed on the scanned surface 18 by the light source elements 11R, 11G, and 11B having different wavelengths. Fourth, the optical scanning device 10 can be miniaturized by turning back the optical path with the concave mirror 17.

  The concave mirror 17 has a non-arc surface shape in at least one direction, so that the speed characteristic on the scanned surface 18 can be corrected. That is, the light beam deflected by the optical deflector 16 can be given constant velocity, and the pixel pitch on the scanned surface 18 can be made uniform.

  Although a Fresnel lens or a refractive lens can be provided immediately before the scanned surface 18 instead of the concave mirror 17, when a Fresnel lens is provided, a shadow is generated in the sawtooth-shaped backcut portion of the Fresnel lens, and the amount of light is reduced. It is not preferable in that a loss occurs. In addition, when a refractive lens is provided, dispersion occurs in a plurality of light fluxes, and the plurality of light fluxes are shifted according to the wavelength, which is not preferable in terms of color shift.

  The scanned surface 18 is a surface having transparency that allows a light beam reflected by the concave mirror 17 to enter and form a two-dimensional image. As the scanned surface 18, for example, a diffusion plate can be used. The diffuser plate has a function of diffusing incident light toward the traveling direction. Although a microlens array can be used in place of the diffuser plate, the microlens array is not preferable in that a shadow is generated between the lenses, resulting in a large light loss and a reduction in light utilization efficiency.

  On the other hand, the diffusion plate is preferable in that it can select the diffusion angle of the transmitted light by the design of the surface shape, and therefore can reduce the light amount loss of the light beam sent to the subsequent optical system. For example, by forming random minute irregularities on the surface of the diffusion plate or forming line-shaped irregularities, it becomes possible to diffuse light only in the necessary range while maintaining high transmittance. It is possible to reduce the light amount loss of the light beam sent to the optical system.

  Here, the arrangement of the optical deflector 16 and the concave mirror 17 will be described in more detail with reference to FIG. FIG. 4 is a diagram for explaining the arrangement of the optical deflector 16 and the concave mirror 17. Referring to FIG. 4, the optical deflector 16 and the concave mirror 17 are arranged so that the signs of the declination angles (angles formed by the incident light beam and the outgoing light beam) are opposite to each other with respect to the total light beam. When the optical deflector 16 and the concave mirror 17 are viewed from a direction perpendicular to the YZ plane (X direction), the optical path of the light beam incident on the optical deflector 16, deflected by the optical deflector 16, and reflected by the concave mirror 17 is “Z”. "Draw the letter.

  In the YZ plane of FIG. 4, if the counterclockwise angle counted from the traveling direction of the incident light beam is defined as a positive deflection angle, the deflection angle 16 d is positive in the optical deflector 16, and the deflection angle 17 d in the concave mirror 17 is Is negative. Thus, the optical deflector 16 and the concave mirror 17 are arranged so that the signs of their declination are opposite to each other. By adopting such an arrangement, the optical path difference between the light beams reaching the upper end and the lower end of the scanned surface 18 is reduced, so that trapezoidal distortion and bending of the image on the scanned surface 18 can be reduced.

  In addition, when trapezoidal distortion or bending occurs in an image without adopting such an arrangement, it is possible to electrically correct the image, but there is a problem that an image becomes dark because invalid pixels are generated. In this embodiment mode, trapezoidal distortion and curvature of an image can be reduced without electrical correction, so that brightness and high image quality can be ensured.

  As described above, in the first embodiment, optical scanning that forms a multicolor image on the scanning surface 18 by two-dimensionally scanning the light beams having different wavelengths emitted from the light source elements 11R, 11G, and 11B. In the apparatus 10, the optical deflector 16 and the concave mirror 17 are arranged in the optical path so that the signs of their declination are opposite to each other. Thereby, the following effects are produced.

  That is, by using the concave mirror 17, the color shift of the image on the scanned surface 18 can be reduced.

  Further, by using the concave mirror 17, the incident angle of the scanned surface 18 can be reduced in all scanning angles, and the luminance of the scanned surface 18 can be increased.

  Further, by arranging the optical deflector 16 and the concave mirror 17 so that the signs of their declination are opposite to each other, the optical path difference of the light beam reaching the upper end and the lower end of the scanned surface 18 is reduced. The trapezoidal distortion and bending of the image on the surface 18 can be reduced.

  Further, by using the concave mirror 17, the optical scanning device 10 can be miniaturized.

  That is, it is possible to reduce the size of the optical scanning device 10 while ensuring the brightness and image quality of the image.

<Variation 1 of the first embodiment>
The first modification of the first embodiment shows an example of an optical scanning device in which the arrangement of optical elements is different from that of the first embodiment. In the first modification of the first embodiment, the description of the same components as those of the already described embodiment is omitted.

  FIG. 5 is a diagram illustrating an optical path of the optical scanning device according to the first modification of the first embodiment. FIG. 5 is a view of the optical scanning device 20 viewed from the same direction as in FIG. However, in FIG. 5, the optical deflector 16, the concave mirror 17, and the surface to be scanned 18 are not shown in the same manner as in FIG. In the optical scanning device 20, the arrangement of the optical deflector 16, the concave mirror 17, and the scanned surface 18 is the same as that of the optical scanning device 10.

  Referring to FIG. 5, in the optical scanning device 20, the light source element 11R, the coupling lens 12R, and the aperture 13R, the light source element 11G, the coupling lens 12G, and the aperture 13G, the light source element 11B, the coupling lens 12B, And the aperture 13B are juxtaposed so that the traveling directions of the respective light beams are substantially parallel.

  The points where the light beams shaped by the apertures 13R, 13G, and 13B are incident on the combining element 14 to be optically combined and the optical system after the combining element 14 are the same as those of the optical scanning device 10.

  As described above, the arrangement of the light source element, the coupling lens, the aperture, the synthesis element, and the like can be determined as appropriate.

<Second Embodiment>
In the second embodiment, an example of an image forming apparatus using the optical scanning device 10 according to the first embodiment will be described. In the second embodiment, the description of the same components as those of the already described embodiments is omitted.

  FIG. 6 is a diagram illustrating an example of an image forming apparatus equipped with the optical scanning device according to the first embodiment. Referring to FIG. 6, the image forming apparatus 50 generally includes the optical scanning device 10 according to the first embodiment, a concave mirror 51, and a semi-transmissive mirror 52. However, as will be described later, the semi-transmissive mirror 52 is not an essential component of the image forming apparatus 50.

  In the image forming apparatus 50, each light beam transmitted through the scanned surface 18 of the optical scanning device 10 is folded (reflected) by the concave mirror 51 and enters the semi-transmissive mirror 52. The semi-transmissive mirror 52 is a mirror whose transmittance in the visible region is not 0% or 100%. For example, a dielectric multilayer film or a wire grid is formed on the side on which the light beam reflected by the concave mirror 51 is incident. Has a reflective surface. The reflecting surface of the semi-transmissive mirror 52 can selectively reflect the wavelength band of the light beam emitted from the light source element. That is, it can have a reflection peak or reflection band including wavelengths λR, λG, and λB, or can be formed so as to increase the reflectance with respect to a specific deflection direction.

  That is, the semi-transmissive mirror 52 selectively reflects the wavelength band of the light beam emitted from the light source elements 11R, 11G, and 11B of the optical scanning device 10. Therefore, it is possible to increase the brightness due to the plurality of image lights having specific wavelengths emitted from the optical scanning device 10.

  The reflecting surface of the concave mirror 51 can be anamorphic. That is, the reflecting surface of the concave mirror 51 can be a reflecting surface having a curvature in a predetermined direction and a curvature in a direction orthogonal thereto. By making the reflecting surface of the concave mirror 51 anamorphic, the curved surface shape of the reflecting surface can be adjusted, and the aberration correction performance can be improved.

  In the image forming apparatus 50, an example in which the concave mirror 51 and the semi-transmission mirror 52 having a flat reflection surface are used has been described. However, instead of the concave mirror 51, a plane mirror is used, and the reflection surface of the semi-transmission mirror 52 is a concave surface. Also good. That is, it is sufficient that at least one optical surface of the mirror that folds each light beam transmitted through the scanning surface 18 of the optical scanning device 10 and the semi-transmissive mirror 52 is concave. Further, depending on the layout of the optical scanning device 10 or the like, two or more concave or flat mirrors may be provided.

  The image forming apparatus 50 can be mounted on a vehicle such as a passenger car. At that time, the semi-transmissive mirror 52 may be integrated with a front window of the vehicle. By disposing the image forming apparatus 50 in front of the driver in a vehicle such as a passenger car, the light beam reflected by the reflecting surface of the semi-transmissive mirror 52 (which may be integrated with the front window or the like) The two-dimensional image of the surface to be scanned 18 enters a predetermined position ahead of the reflecting surface of the translucent mirror 52 (which may be integrated with the front window or the like). It is visually recognized as an enlarged virtual image 59.

  That is, a so-called head-up display can be realized by the image forming apparatus 50. In this case, examples of the two-dimensional image of the scanned surface 18 include vehicle instrument information and map information. Since the virtual image 59 is at a predetermined position in front of the reflecting surface of the transflective mirror 52 (which may be integrated with the front window or the like), the driver focuses on the foreground while driving. The vehicle instrument information, map information, etc. can be viewed without moving greatly.

  As described above, in the image forming apparatus 50, it is possible to obtain the enlarged virtual image 59 of the two-dimensional image formed on the scanned surface 18 of the optical scanning device 10 by the concave mirror 51 and the semi-transmissive mirror 52. A so-called head-up display can be realized.

  Further, in the image forming apparatus 50, the single concave mirror 51 is disposed between the optical scanning device 10 and the semi-transmissive mirror 52, and since there is no refraction system, the occurrence of chromatic aberration can be prevented.

  As is clear from the above description, there are cases where the translucent mirror 52 is included as a component of the image forming apparatus 50 and where the translucent mirror 52 is not included. When the semi-transmissive mirror 52 is not included as a component of the image forming apparatus 50, the function of the semi-transmissive mirror 52 can be provided to the front window of the vehicle.

<Modification of Second Embodiment>
In the modified example of the second embodiment, an example of an image forming apparatus different from the second embodiment is shown. In the modification of the second embodiment, the description of the same components as those of the already described embodiment is omitted.

  FIG. 7 is a diagram illustrating another example of the image forming apparatus equipped with the optical scanning device according to the first embodiment. Referring to FIG. 7, the image forming apparatus 60 is different in that the arrangement of the optical scanning device 10 is different, the concave mirror 51 is deleted, and the semitransparent mirror 52 is replaced with a semitransparent mirror 62. 50 (see FIG. 6). However, as with the image forming apparatus 50, the semi-transmissive mirror 62 is not an essential component of the image forming apparatus 60.

  In the image forming apparatus 60, each light beam emitted from the scanned surface 18 of the optical scanning device 10 is directly incident on the semi-transmissive mirror 62. Similar to the semi-transmissive mirror 52, the semi-transmissive mirror 62 is a mirror that does not have a transmittance in the visible range of 0% or 100%. For example, a dielectric multilayer is formed on the side where the light beam emitted from the scanned surface 18 is incident. It has a reflective surface on which a film or a wire grid is formed. The reflection surface of the semi-transmission mirror 62 has a reflection peak or reflection band that includes the wavelengths λR, λG, and λB, as in the case of the semi-transmission mirror 52, or enhances the reflectance with respect to a specific deflection direction. It can be formed.

  That is, like the semi-transmissive mirror 52, the semi-transmissive mirror 62 selectively reflects the wavelength band of the light beam emitted by the light source elements 11R, 11G, and 11B of the optical scanning device 10. Therefore, it is possible to increase the brightness due to the plurality of image lights having specific wavelengths emitted from the optical scanning device 10. However, unlike the reflective surface (plane) of the semi-transmissive mirror 52, the reflective surface of the semi-transmissive mirror 62 is a concave surface.

  The reflective surface (concave surface) of the semi-transmissive mirror 62 can be anamorphic. By making the reflecting surface of the semi-transmissive mirror 62 anamorphic, the curved surface shape of the reflecting surface can be adjusted, and the aberration correction performance can be improved.

  As described above, in the image forming apparatus 60, it is possible to obtain an enlarged virtual image 59 of the two-dimensional image formed on the scanned surface 18 of the optical scanning device 10 by the semi-transmissive mirror 62 having a curved surface (concave surface). Thus, a so-called head-up display can be realized.

  Further, since the image forming apparatus 60 does not have the concave mirror 51, it can be made smaller than the image forming apparatus 50.

  Similar to the image forming apparatus 50, the component of the image forming apparatus 60 may include the semi-transmissive mirror 62 or may not include the semi-transmissive mirror 62. When the semi-transmissive mirror 62 is not included as a component of the image forming apparatus 60, the function of the semi-transmissive mirror 62 can be provided to the front window of the vehicle. When the transflective mirror 62 is not included as a component of the image forming apparatus 60, the optical scanning device 10 itself functions as the image forming apparatus 60.

  The preferred embodiment and its modification have been described in detail above, but the present invention is not limited to the above-described embodiment and its modification, and the above-described implementation is performed without departing from the scope described in the claims. Various modifications and substitutions can be added to the embodiment and its modifications.

  For example, in each of the embodiments and modifications thereof, an example in which the three light source elements 11R, 11G, and 11B are used in the optical scanning device 10 has been described. However, a single color image is formed using a single light source element. It is good also as a structure. In this case, the synthesis element 14 can be omitted.

  In the image forming apparatuses 50 and 60, the optical scanning device 20 may be mounted instead of the optical scanning device 10.

  Moreover, although the passenger car was mentioned as an example of a vehicle, this invention is applicable also to other vehicles, such as an aircraft and a train.

10, 20 Optical scanning device 11R, 11G, 11B Light source element 12R, 12G, 12B Coupling lens 13R, 13G, 13B Aperture 14 Composite element 15 Lens 15a First surface 15 of lens 15b Second surface 15B, 15R of lens 15 16 Optical deflector 16d, 17d Deflection angle 17 Concave mirror 18 Scanned surface 50, 60 Image forming device 51 Concave mirror 52, 62 Semi-transparent mirror 58 Driver's eyeball 59 Virtual image

JP 2010-145745 A JP 2010-145746 A

Claims (12)

A plurality of light source elements, a coupling lens into which light beams emitted from the plurality of light source elements respectively enter, a combining unit that combines the light beams emitted from the plurality of coupling lenses, and a combining unit. An incident optical system including a lens on which the incident light flux is incident in common ,
An optical deflector for two-dimensionally deflecting a light beam emitted from the incident optical system;
A scanning optical system comprising: a concave mirror on which a light beam deflected by the optical deflector is incident; and a scanned surface having transparency to which a light beam reflected by the concave mirror is incident to form a two-dimensional image; Have
The sign of the declination by the reflecting surface of the optical deflector and the sign of the declination by the concave mirror are opposite to each other,
The concave mirror and the surface to be scanned are arranged at positions shifted from the optical axis of the light beam emitted from the incident optical system ,
The concave mirror is an optical scanning device arranged on the light source element side with respect to an emission point of light emitted from the incident optical system .   The optical scanning device according to claim 1, wherein the plurality of light source elements have different wavelengths. In the incident optical system, the coupling lens is provided for each of the plurality of light source elements,
The optical scanning device according to claim 2, wherein an aperture is provided for each light beam emitted from the coupling lens. The lens is a single meniscus lens that is arranged with the concave surface facing the optical deflector, and converges the respective light beam diameters of incident light beams having different wavelengths,
The meniscus lens is designed to be refracted in the direction in which the variation in the divergence degree converges when the light beams having different wavelengths incident and dispersed on the first surface which is a convex surface are emitted from the second surface which is a concave surface. The optical scanning device according to any one of claims 1 to 3 . The concave mirror, an optical scanning apparatus according to any one of claims 1 to 4 having a non-arcuate sectional shape in at least one direction. An optical scanning device according to any one of claims 1 to 5 ,
A mirror that folds the light beam emitted from the optical scanning device toward a semi-transparent mirror provided outside,
An image forming apparatus in which at least one optical surface of the mirror and the semi-transmissive mirror is a concave surface. An optical scanning device according to any one of claims 1 to 5 ,
A mirror that folds the light beam emitted from the optical scanning device;
A semi-transparent mirror on which the light flux reflected by the mirror enters,
An image forming apparatus in which at least one optical surface of the mirror and the semi-transmissive mirror is a concave surface. The mirror image forming apparatus according to claim 6 or 7, wherein a single concave mirror. An optical scanning device according to any one of claims 1 to 5 ,
An image forming apparatus comprising: a semi-transmissive mirror having a concave surface on which a light beam emitted from the optical scanning device is incident. It said semitransparent mirror, the image forming apparatus of any one of claims 6-9 wherein the light source element selectively reflects the wavelength band of the light flux emitted. The image forming apparatus according to any one of claims 6 to 10 wherein the concave surface is an anamorphic. An image forming apparatus according to any one of claims 6 to 11 is mounted,
The semi-transparent mirror is integrated with the front window,
A vehicle in which a driver can visually recognize an enlarged virtual image of the two-dimensional image at a predetermined position ahead of the reflecting surface of the semi-transmissive mirror.

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