JP2004354482A - Projection optical system, method of manufacturing projection optical system, and projector equipped with projection optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection optical system realizing the reduction of the cost of parts, a method of manufacturing the projection optical system, and a projector equipped with the projection optical system. <P>SOLUTION: The projection optical system 46 which is equipped with a lens holding barrel 100 inside which a specified optical path is set, and lenses 111 to 114 fixed in the holding barrel 100, is characterised in that a straight part opposed to the outer peripheral end faces of the lenses 111 to 114 and having no receiving surface to interrupt the luminous flux incident surfaces of the lenses 111 to 114 and an inclined part continuous to the straight part and expanded toward the one end side of the holding barrel 100 are formed on the inner surface of the holding barrel 100, and the lenses 111 to 114 are fixed in the holding barrel 100 at the outer peripheral end faces of the lenses with an adhesive injected into the inclined part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes a projection optical system including a lens holding cylinder having a predetermined optical path set therein, and a lens fixed in the lens holding cylinder, a method of manufacturing the projection optical system, and a projection optical system. Related to projectors.
[0002]
[Background Art]
Conventionally, a plurality of liquid crystal panels that modulate a plurality of color lights for each color light according to image information, a cross dichroic prism that synthesizes the color lights modulated by each liquid crystal panel, and an enlarged projection of the luminous flux synthesized by these prisms 2. Related Art A projector having a projection optical system for forming a projection image by using a projector is used.
[0003]
A projection optical system used in such a projector includes a lens holding tube having a predetermined optical path set therein, and a lens fixed to the lens holding tube. In order to suppress the occurrence of aberrations such as distortion, chromatic aberration, and the like, the composite lens is configured to include a converging lens and a diverging lens.
[0004]
Here, a lens receiving portion for holding each lens is formed on the inner peripheral surface of the lens holding cylinder. The lens receiving portion protrudes inside the lens holding cylinder and comes into contact with the light beam incident surface of the lens to regulate the movement of the lens in the illumination optical axis direction.
When fixing the lens, after contacting the lens with the lens receiving part, fix it by heat staking with the holding piece formed on the lens holding cylinder, or after contacting the lens receiving part, adhesive on the lens outer periphery Is applied and fixed (for example, Patent Documents 1 and 2).
[0005]
[Patent Document 1]
See JP-A-9-281374 (paragraph [0006], FIG. 1).
[Patent Document 2]
See JP-A-2001-183564 (paragraph [0053], FIG. 5)
[0006]
[Problems to be solved by the invention]
However, in the fixing method disclosed in the above-mentioned patent document, the lens receiving portion projecting from the inner surface of the holding cylinder covers a part of the light beam incident surface of the lens. Since the lens cannot be used as a region, the outer diameter of the lens becomes larger than the light beam transmitting region, and there is a problem that the cost of the lens increases accordingly.
[0007]
An object of the present invention is to provide a projection optical system in which the outer diameter of the lens does not become unnecessarily large and component costs can be reduced.
[0008]
[Means for Solving the Problems]
The projection optical system of the present invention is a projection optical system including a lens holding cylinder having a predetermined optical path set therein, and a lens fixed in the lens holding cylinder. A straight portion that faces the outer peripheral end surface of the lens, has no receiving surface that blocks the light incident surface of the lens, and an inclined portion that is continuous with the straight portion and that opens toward one end of the lens holding cylinder. Is formed, and the lens is fixed to the lens holding cylinder at an outer peripheral end surface of the lens by an adhesive injected into the inclined portion.
[0009]
Here, the injection of the adhesive into the inclined portion may be performed all around the lens outer periphery, but it is preferable to inject the adhesive at three or four positions around the lens outer periphery at substantially equal intervals.
According to the present invention, since the lens receiving surface is not formed in the straight portion, and the adhesive is injected into the inclined portion, the lens is fixed in the holding cylinder at the outer peripheral end surface of the lens, so that the light transmitting surface of the lens is blocked. There is nothing, and almost the entire lens can be used as a light beam transmission area. Therefore, the cost of parts can be reduced by using a lens having a smaller outer diameter than the conventional one.
[0010]
In the present invention, it is preferable that at least a portion having a thickness of 0.5 mm or more is inserted into the straight portion of the outer peripheral end surface of the lens.
According to the present invention, when the thickness of the outer peripheral end face of the lens is inserted into the straight portion by 0.5 mm or more, the position of the lens with respect to the lens holding cylinder in the direction perpendicular to the illumination optical axis is substantially determined. The optical axis of the lens does not largely deviate from the optical axis.
[0011]
In the present invention, it is preferable that a gap of 0.05 mm to 0.1 mm is formed between the outer peripheral end surface of the lens and the straight portion.
According to this invention, since the slight gap is formed, when the lens is advanced or retracted at the straight portion in the lens holding cylinder, the lens end is not caught in the holding cylinder and hinders the reciprocating operation. The forward / backward movement is easily performed, and the adjustment is easy.
In addition, since the position of the lens in the direction perpendicular to the illumination optical axis can be adjusted using a small gap, fine alignment can be performed, and the projection optical system can be made highly accurate.
Furthermore, the adhesive injected into the inclined portion flows into this gap portion by capillary action, and the lens can be fixed and fixed even in the straight portion, and the lens and the lens holding cylinder are arranged vertically and adhered from above. Even when the agent is injected, since there is only a small gap, it does not leak downward from the lens end surface.
[0012]
A method of manufacturing a projection optical system according to the present invention is a method of manufacturing a projection optical system including a lens holding cylinder having a predetermined optical path set therein and a lens supported and fixed in the lens holding cylinder. On the inner surface of the lens holding tube, a straight portion that faces the outer peripheral surface of the lens and has no receiving surface that blocks the light incident surface of the lens, and that is continuous with the straight portion and faces one end of the lens holding tube. A step of adjusting the position of the lens with respect to the lens holding tube by inserting the lens into the lens holding tube, moving the lens along the straight portion, and adjusting the position of the lens with respect to the lens holding tube. After adjusting the position, injecting an adhesive into the inclined portion and fixing the lens to the lens holding cylinder.
According to the present invention, in addition to the effects described in the above-mentioned projection optical system, by adjusting the position of the lens with respect to the lens holding cylinder and then fixing the lens with an adhesive, an appropriate illumination light in the holding cylinder can be obtained. Since the lens can be fixed at the axial position, an optically high-precision projection optical system can be manufactured.
[0013]
In the present invention, a gap of 0.05 mm to 0.1 mm is formed between the outer peripheral end surface of the lens and the straight portion, and after adjusting the position of the lens and before fixing, the lens is moved along the illumination optical axis of the optical path. It is preferable that the method further includes a step of performing centering by moving in the orthogonal direction.
According to the present invention, by including the step of moving the lens in the direction perpendicular to the illumination optical axis in the holding cylinder, the alignment of the lens with respect to the holding cylinder can be performed. Can be manufactured. Further, since optical accuracy can be ensured by this step, the shape accuracy of the lens and the lens holding cylinder can be compensated, and the cost of parts can be reduced. Since the alignment is performed with a small gap, the work of the alignment work is not required.
[0014]
A projector according to another aspect of the invention includes the above-described projection optical system or the projection optical system manufactured by the above-described projection optical system manufacturing method.
According to the present invention, as described above, the cost of the lens can be reduced, and the projection optical system can be made more precise, so that the manufacturing cost is reduced and the projector is made optically more precise. be able to.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[1. Configuration of projector)
FIG. 1 is a diagram schematically showing an optical unit 4 which is a component of a projector 1 including a projection optical system according to the present invention.
Although not shown, the projector 1 includes a projector main body and a resin outer case that houses the projector main body, and is configured in a substantially rectangular parallelepiped shape. The projector body includes a power supply unit, an optical unit 4, and a control board, and drives the optical unit 4 with the external power obtained by the power supply unit while controlling the control board to control the optical unit 4 in accordance with image information. The optical image formed by projection is enlarged and projected.
[0016]
As shown in FIG. 1, the optical unit 4 optically processes a light beam emitted from the light source lamp 416 included in the light source device 411 to form an optical image corresponding to image information, and enlarges the optical image. The unit includes an integrator illumination optical system 41, a color separation optical system 42, a relay optical system 43, an optical device 44, and a projection lens 46.
[0017]
The integrator illumination optical system 41 illuminates the image forming areas of the three liquid crystal panels 441 (the liquid crystal panels 441R, 441G, and 441B for each of red, green, and blue color lights) constituting the optical device 44 substantially uniformly. And a light source device 411, a first lens array 412, a second lens array 413, a polarization conversion element 414, and a superimposing lens 415.
[0018]
The light source device 411 includes a light source lamp 416 and a reflector 417. The light beam emitted from the light source lamp 416 is reflected by the reflector 417 into a parallel light beam, and the parallel light beam is emitted to the outside. A high-pressure mercury lamp is used as the light source lamp 416. In addition to the high-pressure mercury lamp, a metal halide lamp, a halogen lamp, or the like can be used. The reflector 417 employs a parabolic mirror. Instead of a parabolic mirror, a combination of a parallelizing concave lens and an elliptical mirror may be employed.
[0019]
The first lens array 412 has a configuration in which small lenses having a substantially rectangular outline when viewed from the optical axis direction are arranged in a matrix. Each small lens divides the light beam emitted from the light source lamp 416 into a plurality of partial light beams. The contour shape of each small lens is set to be substantially similar to the shape of the image forming area of the liquid crystal panel 441.
[0020]
The second lens array 413 has substantially the same configuration as the first lens array 412, and has a configuration in which small lenses are arranged in a matrix. The second lens array 413 has a function of forming an image of each small lens of the first lens array 412 on the liquid crystal panel 441 together with the superimposing lens 415.
[0021]
The polarization conversion element 414 is disposed between the second lens array 413 and the superimposing lens 415, and is unitized integrally with the second lens array 413. Such a polarization conversion element 414 converts the light from the second lens array 413 into one type of polarized light, thereby increasing the light use efficiency of the optical device 44.
[0022]
Specifically, each partial light converted into one type of polarized light by the polarization conversion element 414 is almost superimposed on the liquid crystal panel 441 of the optical device 44 finally by the superimposing lens 415. In the projector 1 using the liquid crystal panel 441 of the type that modulates polarized light, only one kind of polarized light can be used, so that substantially half of the light flux from the light source lamp 416 that emits another kind of randomly polarized light is not used. For this reason, by using the polarization conversion element 414, all the light beams emitted from the light source lamp 416 are converted into one type of polarized light, and the light use efficiency of the optical device 44 is increased. In addition, such a polarization conversion element 414 is introduced in, for example, Japanese Patent Application Laid-Open No. 8-304739.
[0023]
The color separation optical system 42 includes two dichroic mirrors 421 and 422 and a reflection mirror 423, and converts a plurality of partial light beams emitted from the integrator illumination optical system 41 by the dichroic mirrors 421 and 422 into red (R) and green. (G) and blue (B).
The relay optical system 43 includes an incident side lens 431, a relay lens 433, and reflection mirrors 432 and 434, and has a function of guiding red light, which is the color light separated by the color separation optical system 42, to the liquid crystal panel 441R. ing.
[0024]
At this time, in the dichroic mirror 421 of the color separation optical system 42, of the light flux emitted from the integrator illumination optical system 41, the red light component and the green light component are transmitted, and the blue light component is reflected. The blue light reflected by the dichroic mirror 421 is reflected by the reflection mirror 423, passes through the field lens 418, and reaches the blue liquid crystal panel 441B. The field lens 418 converts each partial light beam emitted from the second lens array 413 into a light beam parallel to its central axis (principal ray). The same applies to the field lens 418 provided on the light incident side of the other liquid crystal panels 441G and 441B.
[0025]
Further, of the red light and the green light transmitted through the dichroic mirror 421, the green light is reflected by the dichroic mirror 422, passes through the field lens 418, and reaches the liquid crystal panel 441G for green. On the other hand, the red light passes through the dichroic mirror 422, passes through the relay optical system 43, further passes through the field lens 418, and reaches the liquid crystal panel 441R for red light.
The relay optical system 43 is used for the red light because the length of the optical path of the red light is longer than the length of the optical path of the other color lights, so that a reduction in light use efficiency due to divergence of light is prevented. That's why. That is, this is for transmitting the partial light beam incident on the incident side lens 431 to the field lens 418 as it is.
[0026]
The optical device 44 modulates the incident light beam according to image information to form a color image. The optical device 44 includes three incident-side polarizing plates 442 on which the respective color lights separated by the color separation optical system 42 enter. A liquid crystal panel 441R, 441G, 441B disposed after each incident side polarizing plate 442, an emission side polarizing plate 443 disposed after each liquid crystal panel 441R, 441G, 441B, and a cross dichroic prism 444. .
[0027]
The liquid crystal panels 441R, 441G, and 441B use, for example, polysilicon TFTs as switching elements.
In the optical device 44, each color light separated by the color separation optical system 42 is modulated according to image information by these three liquid crystal panels 441R, 441G, 441B, the incident side polarizing plate 442, and the exit side polarizing plate 443. To form an optical image.
[0028]
The incident side polarizing plate 442 transmits only polarized light in a certain direction and absorbs other light fluxes of the respective color lights separated by the color separation optical system 42, and a polarizing film is attached to a substrate such as sapphire glass. It was done.
The emission-side polarizing plate 443 is also configured in substantially the same manner as the incidence-side polarizing plate 442, and transmits only polarized light in a predetermined direction among light beams emitted from the liquid crystal panel 441 (441R, 441G, 441B), and transmits other light beams. It absorbs.
The incident-side polarizing plate 442 and the exit-side polarizing plate 443 are set such that the directions of the polarization axes are orthogonal to each other.
[0029]
The cross dichroic prism 444 combines the optical images emitted from the emission-side polarizing plate 443 and modulated for each color light to form a color image.
The cross dichroic prism 444 is provided with a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light in a substantially X-shape along the interface of the four right-angle prisms. The three color lights are synthesized by the multilayer film.
The liquid crystal panel 441, the emission-side polarizing plate 443, and the cross dichroic prism 444 described above are configured as an optical device body 45 that is integrally unitized.
[0030]
These optical components 41 to 45 are housed in an optical component housing (not shown). A projection lens 46 as a projection optical system is attached to one end of the optical component casing, and is exposed from the front side of the outer case. Details will be described later.
[0031]
[2. Configuration of projection lens)
FIG. 2 is a vertical sectional view showing the projection lens 46.
As shown in FIG. 2, the projection lens 46 enlarges and projects the color image synthesized by the cross dichroic prism of the optical device.
The projection lens 46 includes a lens barrel 100 as a lens holding cylinder made of resin or the like in which a predetermined optical path is set, and a plurality of lenses housed inside the lens barrel 100 and sequentially arranged on the illumination optical axis A of the optical path. And a lens group 110 as the lens.
[0032]
The lens group 110 is configured as a group of a total of four lenses including a first group lens 111, a second group lens 112, a third group lens 113, and a fourth group lens 114 in order from the projection side. The image light emitted from the cross dichroic prism enters a fourth group lens 114, which is an aspherical lens, and is then corrected for chromatic aberration by a third group lens 113 in which two lenses are stuck. After being finely adjusted, the image is enlarged and projected to the outside while the distortion is corrected by the first group lens 111 which is an aspheric lens.
[0033]
The lens barrel 100 includes a lens barrel main body 101 fixed to one end portion of the optical component casing via a flange portion 101X, an adjusting cylinder 102 screwed to the light emitting side of the lens barrel main body 101, and a mirror. A rear cylinder 103 is detachably attached to the light beam incident side of the cylinder main body 101.
[0034]
The lens barrel main body 101 houses a second group lens 112 and a third group lens 113. The second lens group 112 and the third lens group 113 are held by lens holding portions 122 and 123 formed inside the lens barrel main body 101, respectively.
[0035]
A first group lens 111 is housed at the projection side end of the adjustment barrel 102, and the first group lens 111 is held by a lens holding unit 121 formed inside the adjustment barrel 102.
By rotating the adjustment barrel 102 with respect to the lens barrel main body 101, the first group lens 111 is advanced and retracted in the direction along the direction of the illumination optical axis A (the left-right direction in FIG. 2), thereby adjusting the focus of the projected image. Can be done. A motor may be provided in the projection lens 46 so that the focus can be adjusted by an automatic operation.
[0036]
A fourth lens group 114 is housed in the rear cylinder 103, and the fourth lens group 114 is held by a lens holding section 124 formed inside the rear frame. Further, the rear barrel 103 is fitted to the flange part 101X of the lens barrel main body 101.
[0037]
FIG. 3 is a longitudinal sectional view showing the lens holding unit.
Each of the lens holding portions 121 to 124 includes a straight portion 125 and an inclined portion 126 which is continuous with the straight portion 125 and which is expanded toward one end of the lens barrel 100.
In this example, the inclined portions 126 of the lens holding portions 121 and 122 both expand toward the projection side of the projection lens 46, and conversely, the inclined portions 126 of the lens holding portions 123 and 124 both On the opposite side of the projection.
The straight portion 125 is a flat cylindrical inner surface extending along the illumination optical axis A, and each of the lenses 111 to 114 is slidable along the illumination optical axis A.
[0038]
A gap S is formed between the straight part 125 and the inclined part 126 and the outer peripheral surface of each of the lenses 111 to 114, and the gap S is filled with an ultraviolet curable adhesive AD. The width of the gap S in the straight portion 125 is 0.05 mm to 0.1 mm, the length is 0.5 mm or more, and the width of the gap S in the inclined portion 126 is 0.5 mm or more. I have.
[0039]
Although not shown, the above-described projection lens 46 is a projection lens provided with a lens barrel holder provided on a mounting table and a lens holder which can be vertically and horizontally adjusted with respect to the lens barrel holder. It is manufactured by a manufacturing device.
The projection lens manufacturing apparatus includes a position adjustment mechanism that adjusts the position of the lens holder, and the position adjustment mechanism moves the lens up and down with respect to the lens barrel holder, that is, a vertical position adjustment mechanism that adjusts the position in the illumination optical axis direction. And a left and right position adjustment mechanism for adjusting the position of the lens to the left and right with respect to the lens barrel holder, that is, in the direction orthogonal to the illumination optical axis. Is to be understood.
[0040]
The procedure for manufacturing the projection lens 46 by such a manufacturing apparatus will be described below.
(1) The lens barrel main body 101 is set on the lens barrel holder with the third lens group 113 facing upward, and the third lens group 113 is mounted on the lens holder. The lens holder may be a suction member that is in close contact with the light beam incident surface of the lens.
(2) The third group lens 113 is inserted into the lens barrel main body 101 by operating the vertical position adjustment mechanism, and the position of the third lens group 113 with respect to the lens barrel main body 101 in the direction of the illumination optical axis A is adjusted. Specifically, while confirming the position of the third lens group 113 with respect to the lens barrel main body 101, the user operates the vertical position adjustment mechanism so that the end surface of the lens barrel main body 101 and the outer peripheral surface of the third lens group 113 are in relative positions in design. Adjust the position so that
(3) After the adjustment of the position of the third group lens 113 in the direction of the illumination optical axis is completed, the right and left position adjustment mechanism is operated to determine the position of the third group lens 113 in the direction orthogonal to the illumination optical axis A with respect to the lens barrel main body 101. Adjust while checking the position. For confirmation of the position, for example, an image of the inner circumference circular portion of the lens barrel main body 101 is taken with a CCD camera or the like, the center of the circle is obtained therefrom by image processing or the like. By determining the center of the outer circumference circle. Then, the position where the centers of both circles coincide with each other is determined as the optimum position, and the alignment is completed.
(4) After the alignment is completed, the adhesive AD is injected into the inclined portion 126 at three or four locations along the outer periphery of the lens, and the adhesive AD is cured by irradiating ultraviolet rays. The group lens 113 is fixed.
[0041]
(5) After the third group lens 113 is fixed to the lens barrel main body 101, two dummy lenses corresponding to the first lens group 111 and the fourth lens group 114 are arranged at design positions with respect to the lens barrel main body 101, and The group lens 112 is mounted on the lens holder and inserted from below the lens barrel main body 101.
(6) A pattern for adjustment is arranged at a designed back focus position by these lens groups, a pattern image is displayed on a screen by irradiating light source light, and an appropriate pattern image is projected. The position adjustment of the second group lens 112 with respect to the third group lens 113 and each of the above-described dummy lenses is performed. When the position adjustment is completed in the same procedure as described above, the second lens group 112 is attached to the lens barrel main body 101 with the adhesive AD. Fix it.
[0042]
(7) When the second lens group 112 and the third lens group 113 are fixed to the lens barrel main body 101, the dummy lens corresponding to the fourth lens group 114 is removed, and the rear barrel 103 is attached to the flange portion 101X of the lens barrel main body 101. In this state, the fourth group lens 114 is mounted on the lens holder, and the position of the fourth group lens 114 is adjusted with respect to the rear cylinder 103 while checking the pattern image. Is fixed to the fourth lens group 114.
(8) Finally, the dummy lens corresponding to the first group lens 111 is removed, and the adjustment cylinder 102 is attached to the lower side of the lens barrel main body 101. After performing the position adjustment of the first group lens 111, the first group lens 111 is adhesively fixed to the adjustment barrel 102.
[0043]
Therefore, according to the present embodiment, the following effects can be obtained.
Since the lens receiving surface is not formed on the straight portion 125 and the adhesive AD is injected into the inclined portion 126, the outer peripheral end surfaces of the lenses 111 to 114 are fixed in the lens barrel 100. There is nothing to block the transmission surface, and almost the entirety of the lenses 111 to 114 can be used as a light flux transmission area. Therefore, the cost of parts can be reduced by using the lenses 111 to 114 having smaller outer diameters than the conventional one.
In addition, when the thickness of the outer peripheral end surfaces of the lenses 111 to 114 is inserted into the straight portion 125 by 0.5 mm or more, the orthogonal position of the illumination optical axis A of the lenses 111 to 114 with respect to the lens barrel 100 is substantially determined. The optical axes of the lenses 111 to 114 do not largely deviate from the illumination optical axis A of the lens barrel 100.
[0044]
Further, since a gap S, which is a slight gap, is formed between the lenses 111 to 114 and the straight portion 125, when the lenses 111 to 114 are advanced and retracted by the straight portion 125 in the lens barrel 100, Since the ends 114 to 114 are not caught in the lens barrel 100 and hinder the forward / backward operation, the forward / backward operation is easily performed and the adjustment is easy.
Since the positions of the lenses 111 to 114 in the direction perpendicular to the illumination optical axis A can be adjusted by using the gap S, fine alignment can be performed, and the projection lens 46 can be made to have high accuracy. Can be.
Further, the adhesive AD injected into the inclined portion 126 flows into the gap S due to the capillary phenomenon, so that the lens can be fixed and fixed also in the straight portion 125, and the lenses 111 to 114 and the lens barrel 100 are arranged in the vertical direction. Even if the adhesive AD is injected from the upper side, there is only a slight gap, and there is no leakage from below.
[0045]
Further, by adopting a manufacturing method having the above-described steps and adjusting the positions of the lenses 111 to 114 with respect to the lens barrel 100, the lenses 111 to 114 are fixed with an adhesive AD, so that the appropriate Since the lenses 111 to 114 can be fixed at positions in the direction of the illumination optical axis A, an optically high-precision projection lens 46 can be manufactured.
Since the alignment is performed using the gap S described above when manufacturing the projection lens 46, the projection lens 46 can be manufactured with higher optical precision, and the lens barrel 100 and the lenses 111 to 114 can be manufactured. Since optical precision can be secured without processing with high precision, the cost of parts can be reduced.
Further, since the projector 1 includes the projection lens 46, the cost of the projection lens 46 can be reduced, and the manufacturing cost of the projector 1 can be reduced.
[0046]
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
For example, in the above-described embodiment, the adhesive for bonding the lenses 111 to 114 is an ultraviolet-curing adhesive AD, and the liquid is cured by irradiating ultraviolet rays. If the lenses 111 to 114 are bonded by heating and curing by heating or the like, batch processing is possible, and the production efficiency is high. Of course, an adhesive other than the ultraviolet curable type and the thermosetting type may be used.
Further, in the above-described embodiment, the ultraviolet curable adhesive AD is injected at three or four locations along the inner periphery of the inclined portion 126 at substantially equal intervals around the outer periphery of the lens. May be injected at any interval, not limited to equal intervals. Further, the injection may be performed over the entire circumference of the straight portion 125, the inclined portion 126, and the lenses 111 to 114.
[0047]
Regarding the manufacturing procedure of the projection lens 46, the holding means and the holding direction of the lens barrel main body 101 and the like are arbitrary, and the lenses such as the lens body 111 and the like are held in the horizontal direction instead of the vertical direction. May be adjusted and adhered and fixed.
Contrary to the above-described embodiment, the second lens group 112 and the third lens group 113 may be positioned while holding the second lens group 112 side of the lens barrel body 101 upward with a lens holder. After positioning one of the lens 112 and the third group lens 113, the lens barrel main body 101 may be held upside down again, and the other may be positioned.
Further, after the adhesive AD is filled, the alignment of the lenses 111 to 114 is performed, and then the adhesive AD may be cured.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an optical unit of a projector including a projection optical system according to an embodiment of the invention.
FIG. 2 is a longitudinal sectional view of a projection optical system according to the embodiment.
FIG. 3 is an enlarged sectional view of a projection optical system according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Projector, 46 ... Projection lens (projection optical system), 100 ... Barrel (lens holding cylinder), 111 ... 1 group lens, 112 ... 2 group lens, 113 ... 3 group lens, 114 ... 4 group lens, 125 ... Straight section, 126: inclined section, A: illumination optical axis, AD: adhesive.

Claims (6)

A projection optical system including a lens holding barrel having a predetermined optical path set therein and a lens fixed in the lens holding barrel,
On the inner surface of the lens holding tube, a straight portion that faces the outer peripheral end surface of the lens and has no receiving surface that blocks the light beam incident surface of the lens, and that is continuous with the straight portion and faces one end of the lens holding tube. And an inclined part that expands
The projection optical system, wherein the lens is fixed to the lens holding cylinder at an outer peripheral end surface of the lens by an adhesive injected into the inclined portion. The projection optical system according to claim 1,
The projection optical system according to claim 1, wherein the outer peripheral end surface of the lens has a thickness of at least 0.5 mm or more inserted into the straight portion. In the projection optical system according to claim 1 or 2,
A projection optical system, wherein a gap of 0.05 mm to 0.1 mm is formed between the outer peripheral end surface of the lens and the straight portion. A method for manufacturing a projection optical system including a lens holding cylinder having a predetermined optical path set therein and a lens supported and fixed in the lens holding cylinder,
On the inner surface of the lens holding tube, a straight portion that faces the outer peripheral surface of the lens and has no receiving surface that blocks the light incident surface of the lens, and that is continuous with the straight portion and faces one end of the lens holding tube. And an inclined part that expands
A step of inserting the lens into the lens holding tube, advancing and retracting the lens along the straight portion to adjust the position of the lens with respect to the lens holding tube, and after adjusting the position, applying an adhesive to the inclined portion. Injecting and fixing the lens with respect to the lens holding cylinder. The method for manufacturing a projection optical system according to claim 4,
A gap of 0.05 mm to 0.1 mm is formed between the outer peripheral end surface of the lens and the straight portion,
A method of manufacturing a projection optical system, comprising a step of moving the lens in a direction orthogonal to an illumination optical axis of the optical path and aligning the lens after adjusting the position of the lens and before fixing the lens. A projector that modulates a light beam emitted from a light source according to image information to form an optical image, and performs enlarged projection.
A projection optical system according to any one of claims 1 to 3, or a projection optical system manufactured by the method for manufacturing a projection optical system according to claim 4 or claim 5. Projector.

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