Patent Publication Number: US-2017371126-A1

Title: Optical projection device and projector

Description:
TECHNICAL FIELD 
     The present invention relates to an optical projection device and a projector which includes the optical projection device. 
     BACKGROUND ART 
     In the related art, a projector is known that modulates light (emission light), which is emitted from a light source, in an optical modulator according to image information, and enlarges and projects the modulated light by an optical projection device. In addition, there is a projector which performs projection on a projection surface of a screen or the like from a short distance at a wide angle of view. In the projector, a short focus optical projection device is used as an optical projection device which is capable of performing projection from the short distance at the wide angle of view. Meanwhile, in recent years, a refracting optical system and a refracting and reflecting compound optical system are used as the optical projection system which performs projection from the short distance at the wide angle of view. 
     PTL 1 discloses an optical projection image forming system which is configured to effectively prevent vignetting of an image forming light flux due to a lens barrel while reducing inclination with respect to an optical axis of oblique light flux in oblique projection performed in an optical system using a fixed lens portion, a moving lens portion, and a concave mirror. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP-A-2011-85922 
     SUMMARY OF INVENTION 
     Technical Problem 
     In an optical projection system in a case where projection (short distance projection) is performed from a short distance at a wide image angle, a distance from an optical projection device to a screen is extremely close, and thus variation in aberration due to focus is large compared to a general optical projection device. In addition, the optical projection system is configured to use a plurality of spherical lenses and non-spherical lenses which are highly sensitive, and thus irregularities in installation positions of the respective lenses significantly have a considerable influence on the variation in aberration, compared to the general optical projection device. Therefore, deterioration in contrast or the like is easily generated on an image, which is projected on a screen, due to the curvature of field and the variation in aberration, and thus there is a problem in that image quality is considerably deteriorated. Therefore, in a case where lens groups are assembled, it is necessary to suppress the irregularities in installation positions of the respective lenses as far as possible, to perform optical adjustment after the assembling, and the like. 
     Therefore, it is desired to provide an optical projection device, which effectively suppresses a variation in aberration due to the irregularities in installation positions of lens groups which form the optical projection system, and a projector which includes the optical projection device. 
     Solution to Problem 
     The present invention is made to solve at least a part of the above-described problems, and can be realized as forms and application examples below. 
     Application Example 1 
     An optical projection device according to the present application example includes: a plurality of lens groups; and a plurality of lens frames that accommodate the lens groups, in which the optical projection device projects incident image light, in which a lens group, which has a diaphragm, in the plurality of lens groups, has a lens frame which is divided between the diaphragm and a lens which is adjacent to the diaphragm, and in which one lens frame, which is acquired through the division, includes an adjustment portion, which maintains a position of an optical axis to be adjusted, with respect to the other lens frame which is acquired through the division. 
     According to the optical projection device, in the lens group which has the diaphragm, the lens frame is divided between the diaphragm and the lens which is adjacent to the diaphragm. Meanwhile, the diaphragm (opening diaphragm) is a place where light flux, which is incident from an image side, is most spread, and, in addition, highly-sensitive lenses are provided in front and rear of the diaphragm. Therefore, in a case where the lens frame is divided between the diaphragm and the lens which is adjacent to the diaphragm, the front and rear lenses of the diaphragm are separated. In a case where a position of the optical axis is adjusted using the adjustment portion (hereinafter, referred to as optical axis adjustment), the diaphragm becomes a most efficient place for controlling the light flux. As described above, in a case where the optical axis adjustment is performed by dividing the lens frame between the diaphragm and the lens which is adjacent to the diaphragm, high definition adjustment is performed, and thus it is possible to correct the aberration due to irregularities and deviation. In addition, it is possible to prevent lens sensitivity from being deteriorated. In a case where it is possible to prevent defects, such as deterioration in contrast and blur, it is possible to improve qualities of a projected image. 
     Accordingly, it is possible to realize the optical projection device which effectively suppresses variation in aberration due to irregularities in installation positions of the lenses. 
     Application Example 2 
     An optical projection device according to the present application example includes: a plurality of lens groups; and a plurality of lens frames that accommodate the lens groups, in which the optical projection device projects incident image light, in which a lens group, which is fixed, in the plurality of lens groups, has a lens frame which is divided at a specified position, and in which one lens frame, which is acquired through the division, includes an adjustment portion, which maintains a position of an optical axis to be adjusted, with respect to the other lens frame which is acquired through the division. 
     According to the optical projection device, in a case where a lens frame of the fixed lens group is divided at the specified position and the optical axis adjustment is performed using the adjustment portion, it is possible to adjust the highly-sensitive lens with high definition, it is possible to prevent the deterioration in the lens sensitivity due to the irregularities in the installation positions of lenses, and it is possible to effectively suppress variation in aberrations. Furthermore, in a case where the fixed lens group, which is not influenced by eccentricity and inclination of the lens due to movement, is adjusted, it is possible to perform higher definition adjustment. 
     Application Example 3 
     An optical projection device according to the present application example includes: a plurality of lens groups; and a plurality of lens frames that accommodate the lens groups, in which the optical projection device projects incident image light, in which a lens group, which is disposed in a most incident side of the light, in the plurality of lens groups, has a lens frame which is divided at a specified position, and in which one lens frame, which is acquired through the division, includes an adjustment portion, which maintains a position of an optical axis to be adjusted, with respect to the other lens frame which is acquired through the division. 
     According to the optical projection device, in a case where the lens frame of the lens group, which is disposed on the most incident side of the incident image light, is divided at the specified position and the optical axis adjustment is performed using the adjustment portion, it is possible to prevent the deterioration in the lens sensitivity due to the irregularities in the installation positions of lenses and it is possible to effectively suppress the variation in aberrations. Furthermore, since the lens group, on the most incident side in which spread of the light flux is small and which has high sensitivity of the installation position of each lens in the optical projection device, is generally adjusted, it is possible to perform higher definition adjustment. 
     Application Example 4 
     In the optical projection device according to the application examples, it is preferable that the adjustment portion includes a plurality of adjusting hole portions and/or adjusting notch portions on an outer circumferential surface of the one lens frame in a radial direction around the optical axis, and the other lens frame is installed on an inner circumferential side of the one lens frame with a gap in the radial direction, and has an exposed outer circumferential surface which faces the adjusting hole portions and/or the adjusting notch portions. 
     According to the optical projection device, for example, adjusting jigs are inserted into the plurality of adjusting hole portions and/or the adjusting notch portions which exist on the outer circumferential surface of the one lens frame, and are in contact with an exposed outer circumferential surface of the other lens frame. Furthermore, in a case where the jigs are moved, the other lens frame is moved with respect to the one lens frame. Therefore, it is possible to perform adjustment which causes the optical axis of the one lens frame to coincide with the optical axis of the other lens frame. Accordingly, it is possible to effectively suppress the variation in aberrations due to the irregularities in the installation positions of the lenses. 
     Application Example 5 
     In the optical projection device according to the application example, it is preferable that the plurality of adjusting hole portions and/or the adjusting notch portions are formed in positions facing each other across the optical axis. 
     According to the optical projection device, the adjusting hole portions and/or the adjusting notch portions are formed in the positions facing each other across the optical axis. Therefore, in a case where the optical axis adjustment is performed, it is possible to maintain the other lens frame in a balanced manner using the jigs, and it is possible to stably move (adjust) the other lens frame. 
     Application Example 6 
     It is preferable that the optical projection device according to the application example further includes a fixing portion that fixes the other lens frame to the one lens frame, in which the fixing portion includes the plurality of fixing hole portions and/or the fixing notch portions, which expose the outer circumferential surface of the other lens frame, on the outer circumferential surface of the one lens frame in the radial direction around the optical axis. 
     According to the optical projection device, after the optical axis adjustment is performed on the lens frames acquired through the division, it is possible to fix the other lens frame to the one lens frame by injecting an adhesive or the like into the exposed outer circumferential surface of the other lens frame from the plurality of fixing hole portions and/or the fixing notch portions which are included in the fixing portion. 
     Application Example 7 
     In the optical projection device according to the application example, it is preferable that the plurality of the fixing hole portions and/or the fixing notch portions are formed at approximately regular intervals. 
     According to the optical projection device, the plurality of fixing hole portions and/or the fixing notch portions are formed approximately at regular intervals, and thus it is possible to perform balanced efficient fixing. Therefore, it is possible to improve qualities with respect to fall and vibration. 
     Application Example 8 
     In the optical projection device according to the application example, it is preferable that the other lens frame includes groove portions which face the fixing hole portions and/or the fixing notch portions. 
     According to the optical projection device, in a case where an adhesive or the like is injected from the fixing hole portions and/or the fixing notch portions, the adhesive is accumulated in the groove portions included in the other lens frame, and thus it is possible to improve adhesive strength in such a way that an adhesive area is enlarged, and the adhesive, which is cured in the groove portions, performs a function as a wedge, or the like. 
     Application Example 9 
     It is preferable that the optical projection device according to the application example further includes a reflecting mirror that reflects light emitted from the lens group. 
     According to the optical projection device, even in a case where the reflecting optical system, which includes the reflecting mirror, is added to the refracting optical system, it is possible to acquire the above-described effects. 
     Application Example 10 
     In the optical projection device according to the application example, it is preferable that the plurality of lens groups are formed to adjust focus. 
     According to the optical projection device, in a case where short distance projection is performed, it is possible to suppress variation in aberration due to the focus adjustment to be small. 
     Application Example 11 
     A projector according to the present application example includes: one of the optical projection devices described above; a light source device that emits light; and an optical modulator that adjusts the light according to image information. 
     According to the projector, the optical projection device which effectively suppresses variation in aberration is included, and thus it is possible to improve quality of a projection image. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective diagram illustrating a use form of a projector according to an embodiment. 
         FIG. 2  is a diagram schematically illustrating an optical unit of a projector. 
         FIG. 3  is a perspective diagram illustrating an optical projection device. 
         FIG. 4  is a schematic sectional diagram illustrating the optical projection device. 
         FIG. 5  is an exploded perspective diagram illustrating the optical projection device. 
         FIG. 6  is an exploded perspective diagram illustrating the optical projection device. 
         FIG. 7  is a perspective diagram illustrating a fourth lens group and a fourth lens frame. 
         FIG. 8  is a sectional diagram illustrating the fourth lens group and the fourth lens frame viewed from an optical axis direction. 
         FIG. 9  is a sectional diagram illustrating the fourth lens group and the fourth lens frame viewed from a direction which is orthogonal to the optical axis direction. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, an embodiment will be described with reference to the accompanying drawings. 
     Embodiment 
     [Use Form and Operation of Projector  1 ] 
       FIG. 1  is a perspective diagram illustrating a use form of a projector  1  according to the embodiment. Meanwhile, the projector  1  includes an optical projection device  5  according to the embodiment. 
     As illustrated in  FIG. 1 , the projector  1  according to the embodiment is installed to be supported by a support device SD that is installed on a wall surface W such that a bottom surface  1 A becomes an upper side. In addition, the screen SC as a projection surface is installed in a position which is a lower side of the wall surface W, on which the projector  1  is installed, and is close to the projector  1 . 
     The projector  1  is a device that modulates emission light, which is emitted from a light source device  31 , in liquid crystal panels  351  as optical modulators according to image information, and enlarges and projects the modulated light as image light through the optical projection device  5  (see  FIG. 2  for all elements). Meanwhile, the projector  1  projects the image light (projection light), which is reflected in a reflecting mirror  71  of the optical projection device  5  (see from  FIG. 2 ), to the screen SC from an opposite side of the bottom surface  1 A. The projector  1  according to the embodiment is formed as a so-called short focus-type projector which performs projection on a large screen (wide angle of view) with respect to the screen SC from a short distance. 
     [Configuration and Operation of Optical Unit  3  of Projector  1 ] 
       FIG. 2  is a diagram schematically illustrating an optical unit  3  of the projector  1 . The optical unit  3  operates under the control of a control portion (not shown in the drawing), and forms the image light according to the image information. As illustrated in  FIG. 2 , the optical unit  3  includes a light source device  31  which includes a light source lamp  311  and a reflector  312 , and an illumination optical device  32  which includes lens arrays  321  and  322 , a polarization conversion element  323 , a superimposition lens  324 , and a collimating lens  325 . In addition, the optical unit  3  includes a color separation optical device  33 , which includes dichroic mirrors  331  and  332  and a reflecting mirror  333 , and a relay optical device  34  which includes an incident-side lens  341 , a relay lens  343 , and reflecting mirrors  342  and  344 . 
     In addition, the optical unit  3  includes an electro-optic device  35  which includes three liquid crystal panels  351  (it is assumed that a red light (R light) liquid crystal panel is  351 R, a green light (G light) liquid crystal panel is  351 G, and a blue light (B light) liquid crystal panel is  351 B) as optical modulators, three incident-side polarizing plates  352 , three emission-side polarizing plates  353 , and a cross dichroic prism  354  as a color composite optical device. In addition, the optical unit  3  includes the optical projection device  5 , and an optical component housing  36  which accommodates the respective optical devices  31  to  35 . 
     With the above-described configuration, the optical unit  3  separates light, which is emitted from the light source device  31  and passes through the illumination optical device  32 , into three color light, that is, R light, G light, and B light in the color separation optical device  33 . In addition, each separated color light is modulated in each of the liquid crystal panels  351  according to the image information, and is formed as modulated light for each color light. The modulated light for each color light is incident into the cross dichroic prism  354 , is composed as the image light, and is enlarged and projected on the screen SC ( FIG. 1 ) or the like through the optical projection device  5 . Meanwhile, since the above-described respective optical devices  31  to  35  are used as an optical system of various general projectors, the detailed description thereof is omitted. 
     [Outline of Optical Projection Device  5 ] 
       FIG. 3  is a perspective diagram illustrating the optical projection device  5 .  FIG. 4  is a schematic sectional diagram illustrating the optical projection device  5 .  FIGS. 5 and 6  are exploded perspective diagrams illustrating the optical projection device  5 . Meanwhile,  FIG. 5  mainly illustrates a first lens frame  61  to a guide barrel  65 .  FIG. 6  mainly illustrates a first adjusting barrel  67  to a cam barrel  66  subsequent to the guide barrel  65 . Meanwhile, one of overlapping members in  FIGS. 5 and 6  is illustrated by being simplified. In addition, a second optical system  7 , an optical projection housing  51  (a housing main body  51 A and a cover  51 B), and a light transmission plate  53  are not illustrated in  FIGS. 5 and 6 . Meanwhile, a unit, which is assembled without the members, is called an optical projection unit  50  and is appropriately used hereinafter. The optical projection device  5 , which includes configurations and operations of the respective members included in the optical projection device  5 , will be described with reference to  FIGS. 3 to 6 . 
     Subsequent to  FIG. 3 , for convenience of explanation, an incident side, to which the image light is incident, is referred to as a rear side and an emission side, in which the image light is emitted from a first optical system  6 , is referred to as a front side, in the first optical system  6  of the optical projection device  5 . In addition, in a drawing of  FIG. 3 , it is assumed that an upper direction on the paper is an upper side and a down direction is a lower side. In addition, left and right directions acquired in a case where the emission side, in which the image light is emitted, is viewed from the first optical system  6  are appropriately used as a left side and a right side. Accordingly, in  FIG. 1 , the optical projection device  5  is installed in a state in which up and down and left and right directions are reversed. As a result, the projector  1  is in a state in which up and down and left and right are reversed. 
     As illustrated in  FIGS. 3 and 4 , the optical projection device  5  includes, as an optical projection system, an optical system in which the first optical system  6  (refracting optical system) is combined with the second optical system  7  (reflecting optical system). The optical projection device  5  according to the embodiment refracts the image light, which is emitted from the cross dichroic prism  354 , in the first optical system  6 , reflects the image light in the second optical system  7  which includes the reflecting mirror  71 , and projects the image light on the screen SC. The optical projection device  5  includes, as the first optical system  6 , a plurality of lens groups in which one or more lenses are set for one lens group, and the lens groups are arranged along an optical axis C. Meanwhile, the optical projection device  5  according to the embodiment is formed as a short focus optical projection device, and the first optical system  6  has a function of performing focus adjustment on incident image light. 
     The optical projection device  5  schematically includes the optical projection housing  51  which is a base of the device, the first optical system  6  and the second optical system  7  which are accommodated in the optical projection housing  51 , and the light transmission plate  53  through which reflection light (projection light) reflected in the reflecting mirror  71  passes. In addition, the optical projection housing  51  includes the housing main body  51 A which accommodates the first optical system  6  and the second optical system  7 , and the cover  51 B which covers an upper portion of the housing main body  51 A and maintains the light transmission plate  53 . 
     The first optical system  6  includes the guide barrel  65 , the cam barrel  66 , first to fourth lens groups L 1  to L 4  which are sequentially arranged along the optical axis C from the front side, and first to fourth lens frames  61  to  64  which respectively maintain the relevant lens groups L 1  to L 4 . In addition, the second optical system  7  includes a non-spherical reflecting mirror  71 . 
     The optical projection device  5  optically processes the image light which is incident from the fourth lens group L 4  in the first optical system  6 , emits the image light from the first lens group L 1  to the reflecting mirror  71  of the second optical system  7 , and reflects the emitted image light in the reflecting mirror  71  and emits the image light as the projection light to an upper direction of the first lens group L 1 . 
     The housing main body  51 A of the optical projection housing  51  includes a flange  511  which is disposed at an incident-side end, a first accommodation portion  512  which extends from the flange  511  to the front side, and a second accommodation portion  513  which extends toward the first accommodation portion  512  and is widening toward the front side. The flange  511  is formed in a rectangular shape in a plan view, and the electro-optic device  35  is fixed to a rear end surface thereof. In addition, the flange  511  includes an insertion hole  5111  at a center, and a rear side of a fourth lens frame  64  which maintains the fourth lens group L 4  is inserted thereinto. 
     The first accommodation portion  512  has a substantially cylindrical shape, is formed in a generally half-cylindrical shape in which an upper side is cut based on a central axis, and accommodates the first optical system  6  therein. In addition, a fixing portion  5121 , which is used to fix the optical projection device  5  to a fixing member (not shown in the drawing) inside the projector  1 , is formed to extend in the left and right directions on the front side and the rear side of an upper end of the first accommodation portion  512 . 
     The second accommodation portion  513  has a cylindrical shape which is widening toward the front side, and is formed in a generally half-cylindrical shape (semicircular truncated cone shape) in which an upper side is cut based on the central axis. A front-side end  5131  of the second accommodation portion  513  is open, and the reflecting mirror  71  is installed on an inner surface which is close to the front-side end  5131 . 
     As illustrated in  FIG. 4 , the cover  51 B of the optical projection housing  51  is provided at an upper portion of the housing main body  51 A to cover from the front-side end  5131  of the second accommodation portion  513  to the extent of the front side of the first accommodation portion  512 . The cover  51 B generally includes a light transmission plate maintenance portion  521  which maintains the rectangular-shaped transparent light transmission plate  53  that passes the projection light reflected in the reflecting mirror  71  at an angle approximately orthogonal to a projection optical axis corresponding to a line binding a center of projection light flux, and a slope  522  which is formed at an angle that does not block the projection light passing through the light transmission plate  53 . Meanwhile, the cover  51 B is fixed to an upper end of the housing main body  51 A by screws. Meanwhile, in a case where the cover  51 B is fixed to housing main body  51 A, it is possible to prevent leakage of light or the like, which is emitted from the first optical system  6 , to the outside. 
     As illustrated in  FIGS. 3 to 6 , the guide barrel  65  includes a front-side cylinder portion  651  and a rear-side cylinder portion  652 . A straight groove  6521 , which is notched along a direction of the optical axis C from the front side to the rear side, is formed to pass through a side surface of the rear-side cylinder portion  652 . Meanwhile, three straight grooves  6521  are formed on a side surface of the rear-side cylinder portion  652  in a circumferential direction around the optical axis C at regular intervals of an angle of 120°. Four fixing portions  6522 , which have screw holes (not shown in the drawing) for fixing the first adjusting barrel  67  that will be described later, are formed at a rear end of the rear-side cylinder portion  652 . In addition, one fixing portion  6523 , which has screw holes (not shown in the drawing) for fixing an adjusting and fixing member  70  which will be described later, is formed to project in a concentric circle shape in the vicinity of a rear-side end of the rear-side cylinder portion  652 . 
     In the front-side cylinder portion  651 , a notch portion  6511 , which has an upper portion that is notched, is formed in accordance with the slope  522  of the cover  51 B that is formed to not interfere in the projection light from the reflecting mirror  71 . The front-side cylinder portion  651  covers outer circumferential sides of the first lens frame  61  and the second lens frame  62  which have forms projecting from the rear-side cylinder portion  652  toward the front side. Meanwhile, the guide barrel  65  is fixed to the inside of the housing main body  51 A by screws. 
     The cam barrel  66  is formed in a cylindrical shape, has an inner side to which the rear-side cylinder portion  652  of the guide barrel  65  is inserted, and is capable of rotating around the optical axis C with respect to the guide barrel  65 . The cam barrel  66  includes the maintenance portion  661  which is formed in a cylindrical shape. A guide groove  662 , which is notched along the direction of the optical axis C from the front-side end to the rear side, and cam grooves  663 ,  664 , and  665 , which are formed on specified paths and prescribe movement operations of the first to third lens groups L 1  to L 3 , are formed on an inner circumferential surface of the maintenance portion  661 . Meanwhile, the guide groove  662  and the three cam grooves  663 ,  664 , and  665  are formed in a circumferential direction of the maintenance portion  661  around the optical axis C at regular intervals of an angle of 120°. 
     A fixing portion  666 , which fixes a lever member that is not shown in the drawing, is formed on an outer circumferential surface of the cam barrel  66 . In a case where the focus adjustment is performed, it is possible to rotationally move and adjust the cam barrel  66  with respect to the guide barrel  65  by rotationally moving the lever member. 
     As illustrated in  FIG. 4 , the first lens group L 1 , the second lens group L 2 , and the third lens group L 3  are formed to be respectively maintained in the first lens frame  61 , the second lens frame  62 , and the third lens frame  63 , to be inserted into the guide barrel  65 , and to be able to move along the optical axis C. Cam pins  61 P,  62 P, and  63 P are formed in the respective lens frames  61 ,  62 , and  63 , and the cam pins  61 P,  62 P, and  63 P are engaged with the straight grooves  6521  of the guide barrel  65  and the cam grooves  663 ,  664 , and  665  of the cam barrel  66 . 
     Furthermore, the respective lens frames  61 ,  62 , and  63  move along the direction of the optical axis C in such a way that the cam pins  61 P,  62 P, and  63 P are guided to intersection points of the straight grooves  6521  and the cam grooves  663 ,  664 , and  665  due to the rotational movement of the cam barrel  66 . 
     As illustrated in  FIG. 4 , the fourth lens group L 4  is maintained in the fourth lens frame  64 . Furthermore, the fourth lens frame  64  is inserted into the guide barrel  65  through the first adjusting barrel  67 , a second adjusting barrel  68 , and an adjusting ring  69 . The optical projection device  5  performs focus adjustment on the image light in a case where the lens groups L 1 , L 2 , and L 3  move. 
     Hereinafter, configurations and assembling of the respective members which are included in the optical projection unit  50  will be described. 
     [Configurations of First Lens Group L 1  and First Lens Frame  61 ] 
     The first lens group L 1  includes one non-spherical lens (referred to as a first lens L 11 ), and is cut to be horizontal to the optical axis C in a specified position on an upper side of the optical axis C. In addition, the left and right directions of the first lens L 11  are cut to be orthogonal to the specified position. The first lens frame  61  includes a maintenance portion  611 , which maintains the first lens group L 1 , and the cam pins  61 P. The maintenance portion  611  is generally formed in a cylindrical shape. Meanwhile, a slope  613  is formed on an upper portion of the outer circumferential surface on the front side of the maintenance portion  611 , together with the slope  522  of the cover  51 B. An accommodation portion  614 , which accommodates the first lens L 11 , is formed on a front-side end surface of the maintenance portion  611 . 
     Meanwhile, the cam pins  61 P are formed to project to the outside in a direction which crosses the optical axis C from the outer circumferential surface in the vicinity of the rear-side end of the maintenance portion  611 . Three cam pins  61 P are provided in the circumferential direction around the optical axis C at regular intervals of an angle of 120°. The cam pins  61 P are formed in a tapered shape which is a cylindrical shape whose tip portion becomes thin. 
     [Configurations of Second Lens Group L 2  and Second Lens Frame  62 ] 
     The second lens group L 2  includes a cemented lens in which the second lens L 21  and the third lens L 22  are cemented, and is cut to be horizontal to the optical axis C from a specified distance on the upper side of the optical axis C. Similarly to the first lens frame  61 , the second lens frame  62  includes a maintenance portion  621 , which maintains the second lens group L 2 , and three cam pins  62 P. A step portion  623  is formed in accordance with the slope  522  of the cover  51 B on an upper portion of the outer circumferential surface of the maintenance portion  621  on the front side. Meanwhile, the second lens group L 2  is maintained through thermal caulking on a front-side end inner circumferential surface, on which the step portion  623  of the maintenance portion  621  is formed. 
     [Configuration of Third Lens Group L 3  and Third Lens Frame  63 ] 
     The third lens group L 3  includes three lenses, that is, a fourth lens L 31 , a fifth lens L 32 , and a sixth lens L 33 , and the fourth lens L 31  and the fifth lens L 32  are the cemented lenses which are cemented. Similarly to the first lens frame  61 , the third lens frame  63  includes a maintenance portion  631 , which maintains the third lens group L 3 , and three cam pins  63 P. The third lens group L 3  is maintained through thermal caulking in a specified position on an inner circumferential surface of a front side of the maintenance portion  631 . 
     [Configuration of Fourth Lens Group L 4  and Fourth Lens Frame  64 ] 
     As illustrated in  FIGS. 4 and 6 , the fourth lens group L 4  includes nine lenses, that is, seventh to fifteenth lenses L 41  to L 49 . The fourth lens frame  64  includes a first division frame  641  and a second division frame  642 . The first division frame  641  maintains the seventh lens L 41  and the eighth lens L 42 , and the second division frame  642  maintains ninth to fifteenth lenses L 43  to L 49 . The fourth lens frame  64  includes a flange  6421  which is formed to project in a direction that crosses the optical axis C on an outer circumferential surface in the middle of the second division frame  642 . The first division frame  641  and the second division frame  642  perform optical axis adjustment (alignment) after fixing lenses to the respective barrels. Thereafter, the first division frame  641  and the second division frame  642  are integrated by being fixed using an adhesive. Meanwhile, the fourth lens frame  64  will be described in detail later. 
     [Assembling of Guide Barrel  65 , Third Lens Frame  63 , Second Lens Frame  62 , and First Lens Frame  61 ] 
     As illustrated in  FIGS. 4 to 6 , the cam pins  63 P of the third lens frame  63  are engaged with the straight grooves  6521  of the guide barrel  65  from the front side, and the third lens frame  63  is inserted into an inner surface of the rear-side cylinder portion  652 . Subsequently, similarly to the third lens frame  63 , the cam pins  62 P are engaged with the straight grooves  6521  of the second lens frame  62  from the front side, and the second lens frame  62  is inserted into the inner surface of the rear-side cylinder portion  652 . Therefore, as illustrated in  FIG. 4 , an area of the maintenance portion  631  (a front-side area of the maintenance portion  631 ), which maintains the third lens group L 3  of the third lens frame  63 , is in a state of being inserted into an inner circumferential surface of a rear side of the maintenance portion  621  of the second lens frame  62 . 
     Subsequently, as illustrated in  FIG. 4 , similarly to the second lens frame  62 , the cam pins  61 P of the first lens frame  61  are engaged with the straight grooves  6521  from the front side, and the first lens frame  61  is inserted into the inner surface of the rear-side cylinder portion  652 . Therefore, an area of the maintenance portion  621  (a front-side area of the maintenance portion  621 ), which maintains the second lens group L 2  of the second lens frame  62 , is in a state of being inserted into an inner circumferential surface of the maintenance portion  611  of the first lens frame  61 . 
     Therefore, the first lens frame  61 , the second lens frame  62 , and the third lens frame  63  are in a state in which the cam pins  61 P,  62 P, and  63 P are maintained by being engaged with the guide barrel  65 . In addition, the tip portions of the cam pins  61 P,  62 P, and  63 P are in a state of projecting from the straight grooves  6521  of the guide barrel  65 . 
     [Assembling of Guide Barrel  65  and Cam Barrel  66 ] 
     The cam barrel  66  guides the tip portions of the projecting cam pins  61 P,  62 P, and  63 P of the first lens frame  61 , the second lens frame  62 , and the third lens frame  63 , which are maintained by being engaged with the guide barrel  65 , to the guide groove  662 , and thus the guide barrel  65  is inserted from the front side of the cam barrel  66 . Therefore, the rear-side cylinder portion  652  of the guide barrel  65  is inserted into the cam barrel  66 . The cam barrel  66  is capable of rotationally moving around the optical axis C with respect to the guide barrel  65 . 
     [Adjustment of Fourth Lens Frame  64  in Optical Projection Device  5 ] 
     Although the fourth lens frame  64  (fourth lens group L 4 ) is a lens group which is fixed in the first optical system  6 , it is possible to adjust (perform back-focus adjustment) a position for the movable first lens frame  61  to the third lens frame  63  (first to third lens groups L 1  to L 3 ) by rotationally moving the fourth lens frame  64  with respect to the guide barrel  65 . Meanwhile, a member, which causes the fourth lens frame  64  to rotationally move, includes the first adjusting barrel  67 , the second adjusting barrel  68 , and the adjusting ring  69 , and a member, which fixes the fourth lens frame  64  to the guide barrel  65  in an adjustment position after the adjustment, includes the adjusting and fixing member  70 . 
     Meanwhile, in the embodiment, it is possible to solely perform position adjustment (optical axis adjustment) by the fourth lens frame  64  according to the invention. The configuration and the adjustment will be described later. 
     [Configuration of First Adjusting Barrel  67 ] 
     As illustrated in  FIGS. 5 and 6 , the first adjusting barrel  67  includes a cylindrical maintenance portion  671 , and a flange  672  which has a rectangular shape on an outer circumferential surface of the maintenance portion  671  in planar view. A screw groove  6711  is formed on an inner surface of the maintenance portion  671 . Hole portions  6721  are formed at respective four corner portions of the flange  672 . The first adjusting barrel  67  is fixed by inserting a front side of the maintenance portion  671  from a rear end side of the rear-side cylinder portion  652  of the guide barrel  65 , causing the flange  672  to be in contact with the rear end of the rear-side cylinder portion  652 , and screwing screws SC 1 , which are inserted into the hole portions  6721  of the flange  672 , into screw holes (not shown in the drawing) of a fixing portion  6522  included in the rear end of the rear-side cylinder portion  652 . 
     [Configuration of Second Adjusting Barrel  68 ] 
     As illustrated in  FIG. 6 , the second adjusting barrel  68  includes a cylindrical maintenance portion  681 , a convex portion  682  which is formed at the rear end of an outer circumferential surface of the maintenance portion  681 , fixing projections  683  which are formed on a front side of the convex portion  682  on the outer circumferential surface, and a concave portion  684  which is formed at the rear end of an inner circumferential surface of the maintenance portion  681 . The fixing projections  683  are parallel to the optical axis C, are formed to project in a direction crossing the optical axis C, and are provided in a circumferential direction around the optical axis C at regular intervals. In addition, a screw groove  6821  is formed on an outer circumferential surface of the convex portion  682 , and a screw portion  6811  is formed on a front-side outer circumferential surface of the maintenance portion  681 . 
     [Configuration of Adjusting Ring  69 ] 
     As illustrated in  FIG. 6 , the adjusting ring  69  includes a ring-shaped maintenance portion  691 , and a fixing portion  692  which extends to face the optical axis C from the rear end of the maintenance portion  691  and includes an opening  6921 . In addition, a screw portion  6911  is formed on an inner circumferential surface of the maintenance portion  691 . 
     [Configuration of Adjusting and Fixing Member  70 ] 
     As illustrated in  FIGS. 5 and 6 , the adjusting and fixing member  70  is generally formed in a rectangular shape in a plan view, and includes a fixing main body  701  which is formed at a curvature along an outer circumferential surface of the fixing portion  6523  of the guide barrel  65 , and a fixing piece  702  which extends on a rear side from a center of the rear end of the fixing main body  701  and is formed to be lower on a side of the optical axis C. A slit-shaped hole portion  7011  is formed in the fixing main body  701  along a radial direction. At a rear-side end of the fixing piece  702 , a notch portion  7021 , which is notched to clamp the fixing projections  683  of the second adjusting barrel  68  in a rotational movement direction, is formed. 
     [Assembling of Fourth Lens Frame  64  with Guide Barrel  65 ] 
     Initially, the fourth lens frame  64 , on which the optical axis adjustment ends, is inserted from the rear side of the second adjusting barrel  68 , and the flange  6421  of the fourth lens frame  64  is positioned in the concave portion  684  of the second adjusting barrel  68 . Subsequently, the adjusting ring  69  (opening  6921 ) is inserted from the rear side of the fourth lens frame  64 , and the screw portion  6911  of the adjusting ring  69  is screwed to the screw groove  6821  of the second adjusting barrel  68 . Therefore, the fourth lens frame  64  is fixed by being interposed between the second adjusting barrel  68  and the adjusting ring  69 . 
     Subsequently, the fourth lens frame  64 , which is interposed between the second adjusting barrel  68  and the adjusting ring  69 , is inserted into the maintenance portion  671  of the first adjusting barrel  67 , which is fixed to a rear-side end of the guide barrel  65 , from the front side. Furthermore, in a case where the screw portion  6811  of the second adjusting barrel  68  is screwed to the screw groove  6711  of the first adjusting barrel  67 , the fourth lens frame  64  is fixed to the guide barrel  65 . 
     With the above-described assembling, the optical projection unit  50  is assembled. Meanwhile, in order to perform back-focus adjustment which will be described later, the optical projection unit  50  is fixed to the optical projection housing  51  (housing main body  51 A), and, thereafter, the back-focus adjustment is performed. 
     [Back-Focus Adjustment of Fourth Lens Frame  64 ] 
     As described above, it is possible to rotationally move the fourth lens frame  64  (fourth lens group L 4 ) with respect to the guide barrel  65  (first adjusting barrel  67 ). In the embodiment, in a case where the fourth lens frame  64  is rotationally moved, it is possible to perform the back-focus adjustment of the optical projection device  5 . In the back-focus adjustment, light (image light), which is incident from an image side, is projected through the optical projection device  5 , and the fourth lens frame  64  is rotationally moved while the projected projection image is visually recognized. 
     Meanwhile, in a case where the fourth lens frame  64  is rotationally moved, the fourth lens frame  64  is rotationally moved while the maintenance portion  691  of the adjusting ring  69  is grasped. In a case where the adjusting ring  69  is rotationally moved, the second adjusting barrel  68  (screw portion  6811 ) varies a screwing state with respect to the first adjusting barrel  67  (screw groove  6711 ). As a result, the second adjusting barrel  68 , the adjusting ring  69 , and the fourth lens frame  64  are rotationally moved with respect to the first adjusting barrel  67  (guide barrel  65 ). 
     [Fixing of Fourth Lens Frame  64 ] 
     In a case where the back-focus adjustment performed by the fourth lens frame  64  ends, subsequently, the fourth lens frame  64  is fixed to the guide barrel  65  by the adjusting and fixing member  70 . Specifically, the fixing main body  701  of the adjusting and fixing member  70  is installed in a specified place of the fixing portion  6523  of the guide barrel  65 . At this time, a state, in which the notch portion  7021  clamps any one of the fixing projections  683  of the second adjusting barrel  68 , is made. Meanwhile, in the embodiment, in a case where the fourth lens frame  64  is rotationally moved, a rotational movement pitch is not arbitrarily and is set to a pitch of the fixing projections  683  (a pitch of 30°). 
     Subsequently, in a state in which the notch portion  7021  of the adjusting and fixing member  70  clamps the fixing projection  683  of the second adjusting barrel  68 , a screw SC 2  is inserted into the hole portion  7011 , and is screwed to the screw hole included in the fixing portion  6523  of the guide barrel  65 . Therefore, it is possible to fix the fourth lens frame  64  to the guide barrel  65 . 
       FIG. 7  is a perspective diagram illustrating the fourth lens group L 4  and the fourth lens frame  64 . Meanwhile,  FIG. 7 ( a )  is a perspective diagram viewed from the front side, and  FIG. 7( b )  is a perspective diagram illustrating a state, in which the fourth lens frame  64  is divided into the first division frame  641  and the second division frame  642 , viewed from the front side.  FIG. 8  is a sectional diagram illustrating the fourth lens group L 4  and the fourth lens frame  64  in the direction of the optical axis C. Meanwhile,  FIG. 8( a )  illustrates a section of the adjustment portion  646  which includes an adjusting barrel  6413  and an adjusting maintenance barrel  6422 , and  FIG. 8( b )  illustrates a section of a fixing portion  647  which includes the adjusting barrel  6413  and the adjusting maintenance barrel  6422 .  FIG. 9  is a sectional diagram illustrating the fourth lens group L 4  and the fourth lens frame  64  in the direction which is orthogonal to the optical axis C. Meanwhile,  FIG. 9  illustrates a section which is orthogonal to the optical axis C based on the adjustment portion  646  and the fixing portion  647 . The fourth lens group L 4  and the fourth lens frame  64  will be described in detail with reference to  FIGS. 4 to 9 . 
     [Configuration of Fourth Lens Group L 4 ] 
     The fourth lens group L 4  includes nine lenses from the seventh lens L 41  to the fifteenth lens L 49 . Specifically, the fourth lens group L 4  includes the seventh lens L 41 , which is formed of a non-spherical lens, and the eighth lens L 42 . In addition, the fourth lens group L 4  includes the ninth lens L 43 , the tenth lens L 44  which is formed of a non-spherical lens, the eleventh lens L 45  and the twelfth lens L 46  which are formed of a cemented lens, the thirteenth lens L 47  which is similarly formed of a cemented lens, the fourteenth lens L 48 , and the fifteenth lens L 49 . 
     [Configuration of Fourth Lens Frame  64 ] 
     The fourth lens frame  64  is formed by being divided into two frames, that is, the first division frame  641  and the second division frame  642  on the front side and the rear side. In the embodiment, the fourth lens frame  64  is divided into two frames, that is, the first division frame  641  and the second division frame  642  between a diaphragm  648 , which will be described later, and the eighth lens L 42  which is adjacent to the diaphragm  648 . 
     The first division frame  641  is a lens frame which is formed in a cylindrical shape on a front side of the diaphragm  648 . The first division frame  641  is formed with a seventh lens accommodation portion  6411  which accommodates the seventh lens L 41  on a front-side inner circumferential side, an adjusting barrel  6413  which is formed in a cylindrical shape that has a larger appearance on a rear side of the seventh lens accommodation portion  6411 , and an eighth lens accommodation portion  6412  which accommodates the eighth lens L 42  inside of the adjusting barrel  6413 . Meanwhile, the seventh lens L 41  is inserted into the seventh lens accommodation portion  6411  from the front side, and is fixed through the thermal caulking. The eighth lens L 42  is inserted into the eighth lens accommodation portion  6412  from the rear side, and is fixed through the thermal caulking. 
     The second division frame  642  is a lens frame which is formed in the cylindrical shape on the rear side that includes the diaphragm  648 . The second division frame  642  is formed with the adjusting maintenance barrel  6422  which is provided to insert the adjusting barrel  6413  of the first division frame  641  into the front side, a diaphragm fixing portion  6428  which fixes the diaphragm  648  inside of the adjusting maintenance barrel  6422 , and a ninth lens accommodation portion  6423  which accommodates the ninth lens L 43  on a rear side of the diaphragm fixing portion  6428 . Meanwhile, before the diaphragm  648  is fixed to the diaphragm fixing portion  6428 , the ninth lens L 43  is inserted into the ninth lens accommodation portion  6423  from the front side, and is fixed through the thermal caulking. 
     The diaphragm  648  is formed in a disk shape, and includes a circular opening  6481  which is formed with a specified diameter from a center. In the embodiment, the diaphragm  648  is formed by a metal plate. The diaphragm  648  is a member which is placed between the eighth lens L 42  and the ninth lens L 43  in the first optical system  6 . Furthermore, the diaphragm  648  is fixed to be in contact with the diaphragm fixing portion  6428  from the front side. Meanwhile, the diaphragm  648  causes effective light to pass through the opening  6481  with respect to light, which is emitted after being optically processed by the ninth to fifteenth lenses L 43  to L 49 , and shades unnecessary light in areas other than the opening  6481 . 
     In addition, the second division frame  642  is formed with a tenth lens accommodation portion  6424  which is formed on a rear side of the ninth lens accommodation portion  6423  in a cylindrical shape and which accommodates the tenth lens L 44 , and an eleventh/twelfth lens accommodation portion  6425  which is formed on the rear side of the tenth lens accommodation portion  6424  in a cylindrical shape that has a larger diameter than that of the tenth lens accommodation portion  6424  and which accommodates the cemented lens of the eleventh lens L 45  and the twelfth lens L 46 . Meanwhile, the tenth lens L 44  is inserted into the tenth lens accommodation portion  6424  from the rear side. In the state, the cemented lens (the eleventh lens L 45  and the twelfth lens L 46 ) is inserted into the eleventh/twelfth lens accommodation portion  6425  from the rear side, and both lenses are fixed in such way that the cemented lens is in contact with the tenth lens L 44  and presses the tenth lens L 44  through the thermal caulking. 
     In addition, in the second division frame  642 , a thirteenth/fourteenth lens accommodation portion  6426 , which accommodates the cemented lens of the thirteenth lens L 47  and the fourteenth lens L 48 , is formed on the rear side of the eleventh/twelfth lens accommodation portion  6425  in a cylindrical shape which has a larger diameter than that of the eleventh/twelfth lens accommodation portion  6425 . Meanwhile, the cemented lens of the thirteenth lens L 47  and the fourteenth lens L 48  is inserted into the thirteenth/fourteenth lens accommodation portion  6426  from the rear side and is fixed through the thermal caulking. 
     In addition, in the second division frame  642 , a fifteenth lens accommodation portion  6427 , which accommodates the fifteenth lens L 49 , is formed in the most rear side on the rear side of the thirteenth/fourteenth lens accommodation portion  6426  in a cylindrical shape which has a larger diameter than that of the thirteenth/fourteenth lens accommodation portion  6426 . Meanwhile, the fifteenth lens L 49  is inserted into the fifteenth lens accommodation portion  6427  from the rear side, and is fixed through the thermal caulking. Meanwhile, the flange  6421  is formed at the boundary between the thirteenth/fourteenth lens accommodation portion  6426  and the fifteenth lens accommodation portion  6427  as described above. 
     [Configurations of Adjusting Barrel  6413  and Adjusting Maintenance Barrel  6422 ] 
     In the adjusting maintenance barrel  6422  of the second division frame  642 , pierced adjusting hole portions  643 , which are used to adjust the first division frame  641 , are formed in the direction crossing the optical axis C from the outer circumferential surface. The adjusting hole portions  643  is included in the adjustment portion  646  which performs the optical axis adjustment (adjustment for coincidence of the optical axis) of the first division frame  641  (the seventh lens L 41  and the eighth lens L 42 ) with respect to the second division frame  642  (the ninth to fifteenth lens L 43  to L 49 ) of the fourth lens frame  64  (fourth lens group L 4 ). Meanwhile, the adjustment portion  646  is a portion which maintains the first division frame  641  (adjusting barrel  6413 ) and the second division frame  642  (adjusting maintenance barrel  6422 ) such that the position of the optical axis C can be adjusted. 
     As illustrated in  FIG. 7 , the adjusting hole portions  643  are formed in approximately rectangular shapes in planar view. In addition, as illustrated in  FIG. 9 , four adjusting hole portions  643  are formed in a circumferential direction (radial direction) around the optical axis C at regular intervals of an angle of 90°. The four adjusting hole portions  643  include adjusting hole portions  6431 ,  6432 ,  6433 , and  6434  in a clockwise direction in  FIG. 9 . 
     In addition, the adjusting hole portions  643  are respectively formed in positions facing each other across the optical axis C. Specifically, the adjusting hole portions  6431  and  6433  are formed in positions facing each other across the optical axis C, and the adjusting hole portions  6432  and  6434  are formed in positions facing each other across the optical axis C. 
     Meanwhile, in a case where the adjusting hole portions  643  are formed through the direction crossing the optical axis C from the outer circumferential surface, areas of an outer circumferential surface of the adjusting barrel  6413 , which face the adjusting hole portions  643  and are positioned on an inner circumferential surface side of the adjusting maintenance barrel  6422 , are in a state of being exposed through the adjusting hole portions  643 . 
     The second division frame  642  is molded through injection molding, and molding of the adjusting hole portions  643  has a mold structure which is taken out in three directions using slide core. Therefore, as illustrated in  FIG. 9 , sectional shapes of the adjusting hole portions  643  become inclined shapes without being parallel sections across the optical axis C. 
     Meanwhile, as requirements for the adjusting hole portions  643 , areas, which are necessary for insertion, and pressing force, which causes directions of pressed pressure due to the facing jigs to face the optical axis C, are necessary in a case where adjusting jigs are inserted into the adjusting hole portions  643  which are facing each other. Therefore, there is no problem if the requirements are satisfied even in a case where the sectional shapes are inclined. 
     In addition, as illustrated in  FIGS. 7 and 8 , a projected surface  6422 A, which projects toward the side of the optical axis C and has a smaller diameter than that of the inner circumferential surface, is formed on an inner circumferential surface of the adjusting maintenance barrel  6422 . The outer circumferential surface of the adjusting barrel  6413  is formed to have a diameter which is smaller than the diameter of the projected surface  6422 A by a radius D. 
     Fixing hole portions  644 , which pass in the direction of the optical axis C from the outer circumferential surface, are formed on the adjusting maintenance barrel  6422  of the second division frame  642 . The fixing hole portions  644  are included in the fixing portion  647  which fixes the first division frame  641  and the second division frame  642  in which the adjustment ends. 
     As illustrated in  FIG. 7 , the fixing hole portions  644  are formed in approximately rectangular shapes in planar view. In addition, as illustrate in  FIG. 9 , three fixing hole portions  644  are formed in the circumferential direction (radial direction) around the optical axis C at regular intervals of an angle of 120°. The three fixing hole portions  644  include fixing hole portions  6441 ,  6442 , and  6443  in the clockwise direction in  FIG. 9 . 
     Meanwhile, fixing groove portions  645 , which face the fixing hole portions  644 , are formed on the outer circumferential surface of the adjusting barrel  6413 . Meanwhile, the fixing groove portions  645  are included in the fixing portion  647 . As illustrated in  FIG. 7 , the fixing groove portions  645  are formed in approximately rectangular shapes in planar view. Meanwhile, in  FIG. 9 , the fixing groove portions  645  include fixing groove portions  6451 ,  6452 , and  6453  corresponding to the fixing hole portions  6441 ,  6442 , and  6443 . 
     [Adjusting Barrel  6413  and Adjusting Maintenance Barrel  6422  Adjusting Method] 
     The fourth lens frame  64  performs the optical axis adjustment using the two frames, that is, the first division frame  641  and the second division frame  642  acquired through the division. Specifically, the fourth lens frame  64  performs adjustment which causes the optical axis C of the second division frame  642 , in which the diaphragm  648  and the ninth to fifteenth lenses L 43  to L 49  are installed, to coincide with the optical axis C of the first division frame  641  in which the seventh lens L 41  and the eighth lens L 42  are installed. 
     Initially, fixing jigs (not shown in the drawing) are installed such that the front side of the second division frame  642  becomes an upper direction. Subsequently, the adjusting barrel  6413  of the first division frame  641  is inserted into an inner surface side of the adjusting maintenance barrel  6422  of the second division frame  642  from the upper direction. In a case of the insertion, the installation projections  6413 A, which are formed at the front-side end of the adjusting barrel  6413 , are inserted into installation reception grooves  6422 B which are formed at the front-side end of the adjusting maintenance barrel  6422 . 
     In the embodiment, a comatic aberration measurement machine is used as an adjusting measurement machine. In addition, in the embodiment, a jig, which includes a probe (not shown in the drawing) that includes a compression coil spring to be inserted into one side hole portion (for example, the adjusting hole portion  6431 ) of the adjusting hole portions  643  facing each other, and a probe (not shown in the drawing) that does not include a compression coil spring to be inserted into another side hole portion (for example, the adjusting hole portion  6433 ), is used as the adjusting jig. Similarly, a jig, which includes a probe (not shown in the drawing) that includes a compression coil spring to be inserted into one side hole portion (for example, the adjusting hole portion  6432 ) of the adjusting hole portions  643  facing each other, and a probe (not shown in the drawing) that does not include a compression coil spring to be inserted into another side hole portion (for example, the adjusting hole portion  6434 ), is used. 
     Furthermore, a state is made in which probes are respectively inserted into the adjusting hole portions  643  and respectively face and press the exposed outer circumferential surface of the adjusting barrel  6413 . Furthermore, in a case where a pressing amount (movement amount) of the probe that does not include the compression coil spring is varied, adjustment is performed such that the optical axes C coincide with each other by moving the position of the first division frame  641  with respect to the second division frame  642 . 
     [Adjusting Barrel  6413  and Adjusting Maintenance Barrel  6422  Fixing Method] 
     In a case where the optical axis adjustment ends, the first division frame  641  and the second division frame  642  are fixed in a state in which the optical axis is adjusted. In the embodiment, fixing is performed using an ultraviolet ray-curing type adhesive. Specifically, a tip portion of a dispenser filled with the adhesive is inserted into three fixing hole portions  644  ( 6441 ,  6442 , and  6443 ) of the second division frame  642  with respect to the fourth lens frame  64  in which the optical axis adjustment ends, and the adhesive is injected into the respective fixing groove portions  645  ( 6451 ,  6452 , and  6453 ), which are formed to face the fixing hole portions  644 , of the first division frame  641 . 
     Therefore, in a case where the adhesive is injected into the fixing groove portions  645  and peripheral gaps thereof, the adhesive is coated in the fixing groove portions  645 , the projected surface  6422 A, the fixing hole portions  644 , and the like. Thereafter, in a case where ultraviolet rays are irradiated, the adhesive is cured. As described above, the first division frame  641  and the second division frame  642  are fixed using the adhesive, and the fourth lens frame  64  is integrated. 
     Meanwhile, the fourth lens frame  64 , which is integrated in such a way that the first division frame  641  and the second division frame  642  are fixed after the optical axis adjustment ends, is inserted into the second adjusting barrel  68 , and is fixed by being interposed between the second adjusting barrel  68  and the adjusting ring  69  in a subsequent process. In addition, the fourth lens frame  64  which is interposed between the second adjusting barrel  68  and the adjusting ring  69  is fixed to the guide barrel  65  through the first adjusting barrel  67 . 
     Meanwhile, the optical projection unit  50 , which is assembled while including the fourth lens frame  64 , is fixed to the housing main body  51 A, in which the reflecting mirror  71  is installed, by screws. Thereafter, in a case where the cover  51 B, on which the light transmission plate  53  is installed, is fixed on an upper portion of the housing main body  51 A by screws, assembling of the optical projection device  5  is completed. Meanwhile, thereafter, as described above, the back-focus adjustment is performed by rotationally moving the entire fourth lens frame  64 . In the end, although description is omitted, the aberration, such as the curvature of field of the projection image, is adjusted by adjusting the position of the first lens group L 1  (first lens L 11 ). Therefore, the assembling and adjustment of the optical projection device  5  end, and the optical projection device  5  is completed. 
     According to the above-described embodiment, advantages below are acquired. 
     According to the optical projection device  5  of the embodiment, in the fourth lens group L 4  which includes the diaphragm  648 , the fourth lens frame  64  is divided into the first division frame  641  and the second division frame  642  between the diaphragm  648  and the eighth lens L 42  which is adjacent to the diaphragm  648 . Meanwhile, the diaphragm  648  is a place where light flux, which is incident from the image side, is most spread, and, in addition, highly-sensitive lenses are provided in front and rear of the diaphragm  648 . Therefore, in a case where the fourth lens frame  64  is divided between the diaphragm  648  and the lens (in the embodiment, the eighth lens L 42 ) which is adjacent to the diaphragm  648 , the front and rear lenses of the diaphragm  648  are separated. In a case where the optical axis adjustment (so-called alignment) is performed using the adjustment portion  646 , the diaphragm becomes a most efficient place for controlling the light flux. As described above, in a case where the optical axis adjustment is performed by dividing the fourth lens frame  64  between the diaphragm  648  and the lens which is adjacent to the diaphragm  648 , high definition adjustment is performed, and thus it is possible to correct the aberration due to irregularities and deviation of the installation positions of the lenses. In addition, it is possible to prevent lens sensitivity from being deteriorated. In a case where it is possible to prevent defects, such as deterioration in contrast and blur, it is possible to improve qualities of a projected image. Accordingly, it is possible to realize the optical projection device  5  which effectively suppresses variation in aberration due to the irregularities in the installation positions of the lenses. With the optical projection device  5 , it is possible to project high definition projection image whose image quality is improved. 
     According to the optical projection device  5  of the embodiment, the adjusting jigs (probes) are inserted into the plurality of adjusting hole portions  643 , which exist in the outer circumferential surface of the second division frame  642  (adjusting maintenance barrel  6422 ), and are caused to be in contact with the exposed outer circumferential surface of the first division frame  641  (adjusting barrel  6413 ). Furthermore, the first division frame  641  is moved with respect to the second division frame  642  by moving the jigs. Therefore, it is possible to perform adjustment which makes the optical axis C of the second division frame  642  coincide with the optical axis C of the first division frame  641 . Accordingly, it is possible to effectively suppress the variation in aberrations due to the irregularities in installation positions of the lenses (the seventh lens L 41 , the eighth lens L 42 , and the ninth to fifteenth lenses L 43  to L 49 ). 
     According to the optical projection device  5  of the embodiment, the adjusting hole portions  643  are formed in positions facing each other across the optical axis C. Therefore, in a case where the optical axis adjustment is performed, it is possible to maintain the first division frame  641  in a balanced manner using the jigs (probes), and it is possible to stably move (adjust) the first division frame  641 . Therefore, it is possible to perform high definition adjustment. 
     According to the optical projection device  5  of the embodiment, the fixing portion  647 , which fixes the first division frame  641  and the second division frame  642 , is included. Therefore, in a case where the adhesive is injected from the fixing hole portions  644  of the second division frame  642 , the adhesive is accumulated in the fixing groove portions  645  included in the first division frame  641 , and thus it is possible to improve adhesive strength in such a way that an adhesive area is enlarged, and the adhesive, which is cured in the fixing groove portions  645 , performs a function as a wedge, or the like. 
     According to the optical projection device  5  of the embodiment, the plurality of fixing hole portions  644  are formed approximately at regular intervals, and thus it is possible to perform balanced efficient fixing. Therefore, it is possible to improve qualities with respect to fall and vibration. 
     According to the optical projection device  5  of the embodiment, even in a case where the second optical system  7  (reflecting optical system), which includes the reflecting mirror  71 , is included in the first optical system  6  (refracting optical system) as the optical projection system, it is possible to acquire the above-described effects. 
     According to the optical projection device  5  of the embodiment, in cases where the first optical system  6  and the second optical system  7  are provided as the optical projection system, the first to third lens group L 1  to L 3  are formed for the focus adjustment, and the short distance projection is performed, it is possible to suppress variation in aberration due to the focus adjustment to be small. 
     The projector  1  according to the embodiment includes the optical projection device  5 , the light source device  31  which emits light, and the optical modulators (liquid crystal panels  351 ) which modulate light according to the image information. Since it is possible to effectively suppress the variation in aberrations by the optical projection device  5 , it is possible to improve the quality of the projection image and project high definition projection image. 
     Meanwhile, the invention is not limited to the above-described embodiment, and can be realized by adding various modifications, improvements, and the like in a scope without departing from the gist of the invention. Modification examples will be described below. 
     In the optical projection device  5  according to the embodiment, the fourth lens frame  64 , which accommodates the fourth lens group L 4 , is divided into the first division frame  641  and the second division frame  642  between the diaphragm  648  and the eighth lens L 42  which is adjacent to the diaphragm  648 . However, division may be performed between the diaphragm  648  and the lens which is adjacent to the diaphragm  648 , and thus division may be performed between the diaphragm  648  and, for example, the ninth lens L 43  (however, in a case of being established in optical design) which is adjacent to the diaphragm  648 . 
     In the optical projection device  5  according to the embodiment, the fourth lens frame  64  which accommodates the fourth lens group L 4  is divided into the first division frame  641  and the second division frame  642  between the diaphragm  648  and the eighth lens L 42  which is adjacent to the diaphragm  648 . However, the lens frame is divided in a specified position with respect to a fixed lens group in the plurality of lens group, one lens frame which is acquired through the division may include an adjustment portion which performs the optical axis adjustment with the other lens frame which is acquired through the division. Furthermore, in a case where the optical axis adjustment is performed using the adjustment portion, it is possible to adjust the highly-sensitive lens with high definition, it is possible to prevent the deterioration in the lens sensitivity due to irregularities in installation positions of the lenses, and it is possible to effectively suppress the variation in aberrations. Furthermore, since a fixed lens group, which is not influenced by eccentricity and inclination of the lens due to movement, is adjusted, it is possible to perform higher definition adjustment. 
     In the optical projection device  5  according to the embodiment, the fourth lens frame  64 , which accommodates the fourth lens group L 4 , is divided into the first division frame  641  and the second division frame  642  between the diaphragm  648  and the eighth lens L 42  which is adjacent to the diaphragm  648 . However, the lens frame is divided in a specified position with respect to a lens group which is disposed on the most incident side of the image light in the plurality of lens groups, one lens frame, which is acquired through the division, may include an adjustment portion which performs the optical axis adjustment with the other lens frame which is acquired through the division. Furthermore, in a case where the optical axis adjustment is performed using the adjustment portion, it is possible to adjust the highly-sensitive lens with high definition, with the result that the deterioration in the lens sensitivity due to irregularities in installation positions of the lenses is suppressed, and thus it is possible to effectively suppress the variation in aberrations. Furthermore, since the lens group, on the most incident side in which spread of the light flux is small and which has high sensitivity of the installation position of each lens in the optical projection device, is generally adjusted, it is possible to perform higher definition adjustment. 
     In the optical projection device  5  according to the embodiment, the fourth lens frame  64  is divided into two frames, that is, the first division frame  641  and the second division frame  642 . However, the fourth lens frame  64  may be divided into three or more frames. 
     In the optical projection device  5  according to the embodiment, the diaphragm  648  is formed as a separate body from the second division frame  642 . However, the diaphragm  648  may be formed to be integrated with the second division frame  642 . In other words, the diaphragm  648  may be formed such that a part of the second division frame  642  functions as the diaphragm  648 . 
     In the optical projection device  5  according to the embodiment, in the fourth lens frame  64 , two adjusting hole portions (the adjusting hole portions  6431  and the adjusting hole portions  6433 , and the adjusting hole portions  6432  and the adjusting hole portions  6434 ) are formed to interpose the optical axis C and face each other in the second division frame  642  as adjusting hole portions  643 . However, three adjusting hole portions may be formed around the optical axis C at regular intervals. 
     In the optical projection device  5  according to the embodiment, in the fourth lens frame  64 , four adjusting hole portions  6431  to  6434  are formed in the second division frame  642 . However, more adjusting hole portions may be formed. 
     In the optical projection device  5  according to the embodiment, in the fourth lens frame  64 , the position of the first division frame  641  is adjusted with respect to the second division frame  642 . However, the second division frame  642  may be adjusted with respect to the first division frame  641 . In this case, modifications may be performed in such a way that the adjusting hole portions  643  and the fixing hole portions  644 , which are formed in the second division frame  642 , are formed in the first division frame  641 , the appearance of the adjusting barrel  6413  of the first division frame  641  is formed to be larger than the appearance of the adjusting maintenance barrel  6422  of the second division frame  642 , and the adjusting maintenance barrel  6422  is inserted into the inner surface side of the adjusting barrel  6413 . 
     In the optical projection device  5  according to the embodiment, the adjusting hole portions  643 , which become holes, are formed as the adjustment portion  646  included in the adjusting maintenance barrel  6422  of the second division frame  642  (fourth lens frame  64 ). However, the adjustment portion  646  is not limited to the hole, and may be formed as the adjusting notch portion which becomes the notch. This is similar to the fixing hole portions  644  as the fixing portion  647 . The fixing portion  647  is not limited to the hole and may be formed as fixing notch portions. 
     In the optical projection device  5  according to the embodiment, the three fixing hole portions  644  are formed at regular intervals (in the circumferential direction (radial direction) around the optical axis C at an angle of 120°). However, the three fixing hole portions  644  may be provided in positions in which it is possible to effectively acquire adhesive strength which can tolerate shocks such as fall and vibration. In addition, two or more hole portions may be provided. 
     In the optical projection device  5  according to the embodiment, the adjusting barrel  6413  of the first division frame  641  (fourth lens frame  64 ) includes the groove portions (fixing groove portions  645 ) which face the fixing hole portions  644 . However, the invention is not limited thereto, and the adhesive may directly coat the areas, which are exposed to face the fixing hole portions  644 , on the outer circumferential surface of the adjusting barrel  6413  without providing the groove portions. 
     Although the optical projection device  5  according to the embodiment includes the second optical system  7  (reflecting mirror  71 ), the optical projection device  5  may not include the second optical system  7 . In addition, although the optical projection device  5  according to the embodiment includes the focus adjusting optical system, it is possible to apply the optical projection device  5  to an optical system which includes zoom adjustment. 
     As illustrated in  FIG. 1 , the projector  1  according to the embodiment is installed on the wall surface W through the support device SD such that the bottom surface  1 A becomes the upper side, and projects the projection image on the screen SC which is installed on the lower side of the projector  1 . However, a way of installing the projector  1  is not limited. The projector  1  may be installed on a ceiling surface, a floor surface, a desk surface or the like, and may project the projection image to the screen SC installed on the wall surface W. In addition, the projector  1  may be installed on a desk surface, and may project the projection image on the same desk surface. 
     In the projector  1  according to the embodiment, the electro-optic device  35  uses a so-called three-plate method in which three optical modulators corresponding to R light, G light, and B light are used. However, the invention is not limited thereto, and an optical modulator using a single plate method may be used. In addition, an optical modulator for improving contrast may be additionally used. 
     In the projector  1  according to the embodiment, the electro-optic device  35  uses transmission-type optical modulators (transmission-type liquid crystal panels  351 ). However, the invention is not limited thereto, and reflection-type optical modulators may be used. 
     In the projector  1  according to the embodiment, the electro-optic device  35  uses the liquid crystal panels  351  as the optical modulators. However, the invention is not limited thereto, and, generally, any one which can modulate incident light flux based on an image signal may be used. For example, it is possible to use another type of optical modulator such as a micromirror-type optical modulator. Meanwhile, it is possible to use, for example, a Digital Micromirror Device (DMD) as the micromirror-type optical modulator. 
     In the projector  1  according to the embodiment, the optical unit  3  uses the lens integrator optical system, which includes the lens arrays  321  and  322 , as the illumination optical device  32  which uniformizes illumination of the light flux emitted from the light source device  31 . However, the invention is not limited thereto, and it is possible to use a rod integrator optical system which includes a light guiding rod. 
     In the optical unit  3  of the projector  1  according to the embodiment, a discharge type lamp, such as an ultra-high pressure mercury lamp is used as the light source lamp  311  of the light source device  31 . However, various solid light emitting elements, such as a laser diode, a Light Emitting Diode (LED), an Electro Luminescence (EL) element, and a silicon light emitting element, may be used. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  projector 
               3  optical unit 
               5  optical projection device 
               6  first optical system 
               7  second optical system 
               31  light source device 
               50  optical projection unit 
               51  optical projection housing 
               51 A housing main body 
               51 B cover 
               53  light transmission plate 
               61  first lens frame 
               62  second lens frame 
               63  third lens frame 
               64  fourth lens frame 
               61 P,  62 P,  63 P cam pin 
               65  guide barrel 
               66  cam barrel 
               67  first adjusting barrel 
               68  second adjusting barrel 
               69  adjusting ring 
               70  adjusting and fixing member 
               71  reflecting mirror 
               351  liquid crystal panel (optical modulator) 
               641  first division frame (the other lens frame) 
               642  second division frame (one lens frame) 
               643  adjusting hole 
               644  fixing hole portion 
               645  fixing groove portion 
               646  adjustment portion 
               647  fixing portion 
               648  diaphragm 
               663 ,  664 ,  665  cam groove 
               6413  adjusting barrel 
               6422  adjusting maintenance barrel 
               6521  straight groove 
             C optical axis 
             D radius 
             L 1  first lens group 
             L 2  second lens group 
             L 3  fourth lens group 
             L 4  fourth lens group 
             L 42  eighth lens (lens which is adjacent to diaphragm)