JP2020074015A - Method for manufacturing projection optical system and method for manufacturing image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a projection optical system having a bending optical system and a mirror optical system and having a function of correcting out-of-focus of the entire projected image on a display screen. SOLUTION: A method of combining a part of a lens group in a refractory optical system while maintaining a distance between a lens surface on the side of the conjugate surface on the most object side of the refraction optical system and a surface on the side of the conjugate surface on the object side. The distance between the first focus adjustment unit, which moves in the linear direction to correct different focus adjustment amounts on the top and bottom of the display screen, and the lens surface on the most object-side conjugate surface side of the refraction optical system and the object-side conjugate surface. It has a second focus adjustment unit that maintains a predetermined distance, and the second focus adjustment unit moves the lens of the refraction optical system to the lens surface on the conjugate surface side of the most object side of the refraction optical system. After adjusting the focus to adjust the focus of the entire display screen by changing the distance to the conjugate surface on the object side, the lens surface on the conjugate surface side of the most object side of the refraction optical system and the conjugate surface on the object side are predetermined. It is characterized by fixing the distance of. [Selection diagram] FIG. 8

Description

  The present invention relates to a method for manufacturing a projection optical system and a method for manufacturing an image display device.

  A general configuration and function of a projection type image display device using a reflection type light valve will be described with reference to FIG.

  FIG. 1 is an explanatory diagram showing an optical arrangement of a general “projector device” as a projection type image display device.

  In the figure, reference numeral LB indicates a light valve, reference numeral LS indicates a lamp light source, reference numeral IR indicates an integrator rod, reference numeral LN indicates an illumination lens, reference numeral M indicates a mirror, reference numeral CM indicates a curved mirror, and reference numeral POS indicates a projection optical system. There is.

The light valve LB is an image display element and is a reflection type.
The lamp light source LS has a lamp LP and a reflector RF, and emits illumination light for illuminating the light valve LB.

  The integrator rod IR, the illumination lens LN, the mirror M, and the curved mirror CM configure an illumination optical system that guides the illumination light emitted from the lamp light source LS to the light valve LB.

  The integrator rod IR is a light pipe in which four mirrors are combined in a tunnel shape, and guides light incident from the entrance portion to the exit portion while being reflected by the mirror surface.

  The projection optical system POS projects the reflected light from the light valve LB toward a projection surface such as a screen, and enlarges and forms the “image displayed on the light valve LB” on the projection surface.

  The light valve LB is a "DMD (digital micromirror device)" in this example, and is composed of minute mirrors arranged in an array. The normal directions of the individual micromirrors can be changed independently of each other, for example, within a range of ± 12 degrees.

  The light emitted from the lamp LP is reflected by the reflector RF and focused on the entrance of the integrator rod IR. The light incident from the entrance portion is guided while being repeatedly reflected in the integrator rod IR, and exits from the exit portion as light having a uniform illuminance “uniformed in illuminance”.

  The light emitted from the integrator rod IR illuminates the light valve LB through the illumination optical system including the illumination lens LN, the mirror M, and the curved mirror CM.

  The illumination lens LN, the mirror M, and the curved mirror CM of the illumination optical system make the emitted light at the exit of the integrator rod IR "a surface light source of uniform illuminance with uneven light quantity", and generate an image of this surface light source. It is formed on the light valve LB. That is, the light valve LB is illuminated with illumination light having a uniform illuminance.

  The tilt angle of the minute mirror in the light valve LB is set so that the reflected light from the minute mirror enters the projection optical system POS when it is −12 degrees and does not enter the projection optical system POS when it is +12 degrees, for example. The positional relationship between the light valve LB and the projection optical system POS is determined, and the “direction of incidence of light emitted from the curved mirror CM on the light valve LB” is set.

  An image can be displayed on the light valve LB by adjusting the tilt of each micro mirror according to the pixel of the image to be projected and imaged on the projection surface. The image displayed in this way is called a "display image".

  By displaying an image on the light valve LB and irradiating the light valve LB with illumination light in this way, the reflected light of each micromirror entering the projection optical system POS is converted into an imaging light flux by the projection optical system POS and projected. The image is projected and formed as an enlarged image of the above image on the surface. The image formed on the projection surface in this manner is called a "projection image".

  Since the light valve LB is illuminated with “light having a uniform illuminance distribution”, the projection image on the projection surface, which is an enlarged image of the displayed image, also has a uniform illuminance distribution. In this way, a "digital image" can be displayed on the projection surface.

  The above is a description of image display by a general projector device.

  As described above, the function of the projection optical system POS is to “image the projection image, which is the real image of the display image displayed on the light valve LB, on the projection surface such as a screen”. The size of the projected image to be displayed and the distance from the projector device to the projection surface vary depending on the specific usage of the projector device.

“Focusing” is required to form a projection image on the projection surface.
In the “normal projector device” shown in FIG. 2A, the projection optical system POS1 has “coaxial rotational symmetry”, and the projection image on the screen SC, which is the projection surface, is focused by the entire projection optical system POS1. A "whole extension method" for moving the subject to focus and a focusing method for moving a focus group in which one or more lenses in the lens system are set are common. In each of FIG. 2 and the subsequent figures, the optical axis of the lens system portion of the projection optical system which is coaxially rotationally symmetric is represented by the symbol “AX”.

  As shown in FIG. 2B, "a refractive optical system POSL1 composed of a plurality of lenses and a mirror optical system POSM1 composed of a non-coaxial reflecting surface that does not share an optical axis with the refractive optical system POSL1 (see FIG. In the above example, a projector device using a projection optical system constituted by one concave mirror is known and is becoming widespread.

  In such a projector device, a projector device capable of projecting at a closer distance (ultra-shorter distance) than ever has been proposed and is being implemented.

When "projecting an image at a close range or an ultra close range" on the screen SC, it is usually necessary to set the projection position of the projected image to "above the projector device" so that the projected image is easy to see.
Therefore, generally, as shown in FIG. 2, the center of the image display element LB (DMD in this case) is deviated from the optical axis AX of the projection optical system and arranged eccentrically.
Then, the image quality is maintained by using a wide-angle lens as the projection optical system in order to "take a wide range of performance guarantee of the projection optical system".
However, there is a limit to the widening of the projection optical system by the coaxial rotationally symmetric lens system, and in order to project the projection image from the "super close position closer to the screen SC", the mirror optical system "makes an optical path". There is a need.

  There is also a "diagonal projection" method in which the optical path of the projection optical system by the lens system is folded back by a plane mirror and the optical axis of the projection optical system is tilted with respect to the screen to project at a short distance, but short-distance projection However, there is a problem of “trapezoidal distortion” in which the display screen is distorted into a trapezoidal shape.

In the projection method shown in FIG. 2B, the "trapezoidal distortion" of the projected image can be effectively corrected by setting the mirror surface shape of the concave mirror which constitutes the mirror optical system POSM1 to "free curved surface".
Non-Patent Document 1 has a detailed description of such “correction of trapezoidal distortion by a mirror having a free-form surface”.

  In the projector device as shown in FIG. 2B, in which the refraction optical system POSL1 and the mirror optical system POSM1 are used, and the trapezoidal distortion is corrected by using the “free-form curved mirror” in the mirror optical system POSM1, A "floating focus method" is conceivable as a focusing method suitable for "focusing".

  In this case, the "floating focus method" fixes the "one or more lenses" closest to the light valve LB (DMD) and moves the other two or more lenses, lens groups, and mirrors in the optical axis direction to focus. This is a focusing method that combines the two.

  In particular, focusing at very close and ultra close distances is called "floating focus" because it "moves multiple lens groups like floating trees to focus", especially "interchangeable lenses for single-lens reflex cameras". Widely used in.

  In focusing by the whole extension method or “single lens or lens group”, the trapezoidal distortion tends to be insufficient when the projection image is projected on the screen SC from a close range, and the curvature of field is corrected. Also becomes insufficient, and there is a problem that the center and the periphery of the display screen are out of focus.

  In the floating focus method, image distortion that occurs when a projected image is projected from a close distance to the screen SC is mainly corrected by a “non-coaxial curved mirror”, so that trapezoidal distortion correction and It is also possible to excellently correct the field curvature.

This will be described more specifically.
FIG. 3A shows a “diagonal projection” projector device. For simplicity of illustration, the plane mirror that folds the optical path is omitted in the figure.

  The projection image is projected and displayed on the screen SC by the projection optical system POS0.

  The light valve LB is a “DMD”, and its image display surface is a “horizontally long rectangular shape” in which the vertical direction (Y direction) of the screen SC is short as shown in the upper diagram of FIG. The projected image projected on top is "trapezoidal" as shown in the lower diagram of FIG.

  FIG. 4A shows a projection-type projector device having a projection optical system configured by a refractive optical system POSL1 and a mirror optical system POSM1. The mirror optical system POSM1 is a concave mirror.

  In this projector device, the image display surface of the light valve LB (DMD) has a rectangular shape as shown in the upper diagram of FIG. 4B, and the dioptric system POSL1 converts the real image of the image display surface into the intermediate image Im0. As an image, an image is formed between the refractive optical system POSL1 and the mirror optical system POSM1, and the mirror optical system POSM1 forms and projects a projection image having the intermediate image Im0 as an object image on the screen SC.

  The intermediate image Im0 formed by the refraction optical system POSL1 has a “trapezoid shape with a narrow upper portion” as shown in the middle diagram of FIG. 4B, and is imaged with such distortion. Then, this distortion aberration is corrected by the mirror optical system POSM1 to form a "rectangularly corrected projection image" on the screen SC as shown in the lower diagram of FIG. 4 (b).

  In the projector device of FIG. 4, in order to display a “smaller projection image” on the screen SC, as shown in FIG. 5A, the screen SC is moved in the Z direction (from the position of FIG. 4A). Consider a case where the lens is moved to the right side and the focusing is performed by the "whole extension in the Z direction" of the refractive optical system POSL1 which is a coaxial system.

  In this case, since the distortion of the intermediate image Im0 hardly changes before and after the entire extension of the refractive optical system POSL1, the shape of the intermediate image Im0 is as shown in the middle diagram of FIG. As in the case of the lower diagram of FIG. 5, “the trapezoidal distortion in which the upper side is shortened” occurs in the projected image on the screen SC as shown in the lower diagram of FIG.

This phenomenon will be described in more detail with reference to FIGS.
FIG. 6A shows a state of FIG. 4A viewed from above, that is, an XZ cross section of FIG. 4A.

  As shown in FIG. 6A, in the projection optical system using the concave mirror POSM1, the angles of light traveling upward in the Y direction and downward in the Y direction on the display screen on the screen SC are different in the XZ section.

  FIG. 6C shows the shape of a projected image when proper projection is performed, as shown in FIG. 6A, and has a rectangular shape.

  When the screen SC is moved as shown in FIG. 5A, the position in the X direction reaching the screen SC is different between the upper and lower parts of the display screen as shown in FIG. 6B showing the XZ cross section in this state. As shown in FIG. 6D, "trapezoidal distortion with a short upper side" is generated.

  When the distance between the light valve and the refracting optical system (distance in the light valve normal direction) is appropriate, the "floating focus method" is very effective for correcting trapezoidal distortion and the above-mentioned field curvature correction. is there.

  In focusing by the floating focus method, field curvature correction has a strong effect, and therefore, for example, as shown in FIG. 7, the screen SC is set at the screen position SC (1) (the state of FIG. 4A). To the screen position SC (2) (the state of FIG. 5 (a)), as in the case of approaching the curved mirror POSM1, “when the focus adjustment amount is significantly different between the top and bottom of the display screen”. It is valid.

  However, if "the amount of focus adjustment you want to adjust is the same" on the entire display screen, the focus adjustment by the floating focus method does not work effectively. In such a case, "the focus adjustment by the whole extension method or the front group extension method" is performed. Is valid.

  Conventionally, various methods are widely known for focusing the projector device (for example, Patent Documents 1 to 3).

  Focusing by the floating focus method mainly has the function of correcting the "focus deviation between the center and the periphery" of the display screen, but "variation in the distance between the refractive optical system and the light valve" and "variation in the focal length of the refractive optical system" Is not suitable for correcting the case where the focus of the entire projected image is “blurred”.

  The present invention has been made in view of the above-described circumstances, and has a refraction optical system and a mirror optical system, and has a function of correcting "a different focus adjustment amount between upper and lower sides" of a display screen, and "a whole projection image. It is an object of the present invention to provide a method for manufacturing a projection optical system having a function of correcting "out of focus".

  The method for manufacturing a projection optical system of the present invention includes, in order from the object side, a refracting optical system including a plurality of lens groups, and a mirror optical system having a curved mirror. While maintaining the distance between the conjugate surface on the conjugate surface side and the conjugate surface on the object side, a part of the lens group in the refractive optical system is moved in the normal direction of the conjugate surface on the object side to display the display screen. A first focus adjustment unit that corrects different focus adjustment amounts between upper and lower sides, and a distance between a lens surface on the most object-side conjugate surface side of the refractive optical system and the object-side conjugate surface is maintained at a predetermined distance. And a second focus adjusting section for producing a projection optical system for enlarging and projecting an image of an object, wherein the second focus adjusting section moves a lens of the refracting optical system. Conjugate of the refraction optical system closest to the object side After performing focus adjustment to adjust the focus of the entire display screen by changing the distance between the lens surface on the side and the conjugate surface on the object side, with the lens surface on the conjugate surface side of the most object side of the refractive optical system. It is characterized in that the predetermined distance from the conjugate plane on the object side is fixed.

  As described above, the projection optical system manufactured by the manufacturing method of the present invention has two focus adjusting units, which are the first and second focus adjusting units, which are separate from each other, and the first focus adjusting unit is When the real image of the image display device is projected on the projection surface for focusing, floating focus type focusing is possible.

In addition, the second focus adjustment unit changes the distance between the most object-side conjugate surface-side lens surface of the refraction optical system and the object-side conjugate surface, so as to "disperse the distance between the refraction optical system and the light valve". It is possible to effectively correct "out-of-focus blur of the entire projected image" caused by "variation of focal length of refraction optical system" and adjust the focus of the entire projected image.

  The focus adjustment of the projection optical system is performed by the second focus adjustment unit, and the second focus adjustment unit is fixed after this focus adjustment. Therefore, the second focus adjustment unit is fixed during the operation of the first focus adjustment unit. ing.

It is a figure for explaining a general projector device as an image display device. It is a figure for demonstrating the focus adjustment of a projection image. It is a figure for explaining trapezoidal distortion of a projection image. It is a figure for demonstrating correction of a trapezoidal distortion. FIG. 7 is a diagram for explaining a case where the trapezoidal distortion is not sufficiently corrected in the image projection apparatus using the mirror optical system. FIG. 7 is a diagram for explaining a case where the trapezoidal distortion is not sufficiently corrected in the image projection apparatus using the mirror optical system. FIG. 6 is a diagram for explaining a case where the screen position changes in an image projection device using a mirror optical system. It is a figure which shows the principal part of the reference example 1. FIG. 9 is a diagram for explaining Reference Example 2. It is a figure for explaining an embodiment. It is a figure for demonstrating the concrete example of the refractive optical system used in the reference examples 1 and 2 and embodiment. It is a figure which shows an example of a concrete structure of a refraction optical system. FIG. 6 is a diagram showing data of the refractive optical system portion of the projection optical system of Example 1. FIG. 3 is a diagram showing data of Example 1. 5 is a diagram showing data on the mirror surface shape of the concave mirror in Example 1. FIG. It is a figure for explaining the projector device which loaded the exterior OC on the projection optical system. It is a figure for explaining the projector device which loaded the exterior OC on the projection optical system.

  Hereinafter, embodiments and specific examples of the projection optical system and the image display device manufactured by the manufacturing method of the present invention will be described.

  In the following description, “DMD” is exemplified as the light valve which is the image display element, but the image display element in the image display device manufactured by the manufacturing method of the present invention is not limited to the DMD, of course.

  That is, in the image display device manufactured by the manufacturing method of the present invention, it is possible to use various known light valves other than the DMD, such as LD panels and LCOS panels.

  Further, in order to avoid complexity of the drawings, in the drawings used to describe the following embodiments, a lamp light source that is a light source and an illumination optical system that guides and illuminates illumination light from the lamp light source to a light valve are shown. Omit it.

  Actually, the integrator rod IR, the illumination lens LN, the mirror M, and the curved mirror CM are illumination optical systems with curved mirrors as shown in FIG. 1, and the light valve LB (DMD ) Is assumed to be illuminated.

  Of course, the types and configurations of the light source and the illumination light source are not limited to this case, and it goes without saying that appropriate types are used according to the type and form of the image display element.

"Embodiment 1"
FIG. 8 shows a main part of the first embodiment of the projection optical system manufactured by the manufacturing method of the present invention.

  The light valve LB is a DMD and is held by the optical housing HS.

A lens barrel CL is connected to the optical housing HS via an intermediate member InA, and a plurality of lenses forming a “refractive optical system” of a projection optical system are arranged in the lens barrel CL.
In the first embodiment, the “refractive optical system” includes four lens groups, that is, a first lens group LI, a second lens group LII, a third lens group LIII, and a fourth lens group LIV arranged from the light valve LB side. It is configured.

  Reference numeral RM indicates a "folding mirror" and reference numeral CNM indicates a concave mirror forming a "mirror optical system".

  When illumination light from a light source (not shown) is applied to the image display surface of the DMD that is the light valve LB by an illumination optical system (not shown), the reflected light from the image display surface is intensity-modulated by the display image displayed on the DMD. And enters the “refractive optical system” of the projection optical system.

  The light beam emitted from the refracting optical system is reflected by the folding mirror RM, and when it is reflected by the concave mirror CNM, it becomes an image-forming light beam, which is directed to a projection surface (screen) not shown and a display image is displayed on the projection surface. An image of the enlarged projection image is formed.

  The folding mirror RM is attached to the holder HL via the intermediate member InB.

  In such an "optical system passing through the folding mirror RM", "a real image of a display image is provided on the optical path between the refractive optical system and the concave mirror RM so that the degree of diffusion of the light reflected by the folding mirror RM can be reduced. It is preferable to focus the light flux once by forming “” as an intermediate image.

Focusing by focusing will be described.
Although not shown in FIG. 8, when the screen position is brought close to the screen position SC (1) in FIG. 7 from the screen position SC (2), the difference between “up and down of the screen” of the projected image is different. In order to correct the focus adjustment amount, the focus is adjusted by the floating focus method.
In the form 1, the second lens unit LII and the third lens unit LIII out of the four lens units constituting the refracting optical system are moved in the optical axis direction to perform focusing.

  Although the structure of the lens barrel CL is not shown in detail in FIG. 8, in order to move the second lens unit LII and the third lens unit LIII, for example, a cam groove is formed in the lens barrel CL and the second lens unit LII is moved. By attaching a pin that fits the cam groove to each of the LII and the third lens group LIII, fitting the pin into the cam groove, and rotating the lens barrel CL, the second lens group LII and the third lens group LIII are different from each other. Can be moved in any direction.

  Here, the lens barrel CL is treated as one component for simplification of the description, but in reality, it is general to adopt a “more complicated configuration” with a plurality of components.

  This cam mechanism is referred to as a "first focus adjustment section".

By the way, if a plurality of optical housings HS are manufactured, "dimensional variation" naturally occurs in the product.
Therefore, when the lens barrel CL is directly assembled to the optical housing HS, the distance between the light valve LB and the first lens group LI in FIG. 8 varies according to “dimensional variation”.
Further, in the first embodiment, when a plurality of lenses of the refractive optical system configured by the first to fourth lens groups LI to LIV and a plurality of concave mirrors CNM are manufactured, there are “shape variations”, and in particular, “ The “focal length of the refractive optical system” varies, and the “optimal distance” between the light valve LB and the first lens group LI varies.

  The "intermediate member InA" is arranged so that the distance between the light valve LB and the first lens group LI can be optimized even if these two types of "variation" occur.

  As the intermediate member InA, for example, a plurality of thin plates having a thickness of about 0.1 mm is used, and the total number of the intermediate members InA is changed by changing the number of thin plates interposed between the optical housing HS and the lens barrel CL. Can be adjusted. By doing so, the distance between the light valve LB and the first lens group LI can be adjusted in units of 0.1 mm.

  Alternatively, as another method, a plurality of plate members made of aluminum or the like having different thicknesses in units of 0.1 mm are prepared as the intermediate member InA, and an “aluminum plate having an optimum thickness is provided for each combination of the optical housing HS and the refractive optical system. By selecting “” and inserting it, the distance between the light valve LB and the first lens group LI can be adjusted in units of 0.1 mm.

After the positional relationship between the optical housing HS and the lens barrel CL is adjusted by the intermediate member InA, it is preferable to “fix them to each other” with each other in order to fix these positional relationships.

  As described above, when the positional relationship between the light valve LB and the first lens group LI is optimized by the intermediate member InA, the positional relationship between the fourth lens group LIV and the concave mirror CNM is “initially assembled” by the optimizing operation. Relationship. ”

  To correct this, the intermediate member InB interposed between the folding mirror RM and the holder HL is used to adjust the optical path length between the fourth lens group LIV and the concave mirror CNM.

  Similarly to the intermediate member InA, if the intermediate member InB is made of a plurality of thin plates or aluminum plates having different thicknesses, the optical path length can be easily adjusted with high accuracy.

  Further, when thin plates are used as the intermediate members InA and InB, if a plurality of position fixing points (for example, screws fixing points) are formed between the intermediate member InA and the optical housing HS, or between the intermediate member InB and the holder HL, each position can be formed. By changing the number of thin plates to be inserted at the fixed points, it is possible to correct the "tilt error between the light valve LB and the refracting optical system" or the "tilt error between the curved mirror CNM and the refracting optical system".

  The intermediate members InA and InB described above form a “second focus adjustment unit”.

  Since the intermediate member InA can be adjusted only by sandwiching the intermediate member InA between the lens barrel CL and the optical housing HS, no special structure is required, and the optical housing HS and the lens barrel CL, which have heat near the light valve LB, are in direct contact with each other. By not doing so, it becomes difficult for heat to transfer to the lens barrel CL, and focus shift due to thermal expansion of the lens does not occur.

That is, the image display device of mode 1 has the first and second focus adjustment units as described above.
In the first focus adjusting unit, when the distance between the projection surface and the concave mirror CNM is changed, the second lens unit LII and the third lens unit LIII in the refracting optical system are “displaced by different movement amounts”. Focusing is performed with the floating focus method.

  On the other hand, in the second focus adjustment unit, in the process of assembling the optical system of the image display device, by adjusting the positional relationship of the light valve, the refraction optical system, and the concave mirror (mirror optical system) appropriately, Make sure the projected image is in focus. Then, after adjusting the positional relationship, the second focus adjustment unit is fixed.

"Second Embodiment"
The second embodiment will be described with reference to FIG.

  The form 2 is a modification of the form 1 described above, and is the intermediate member in the form 1 in which the “structure for adjusting the distance between the light valve LB and the first lens group LI” of the second focus adjustment unit is used. In this example, InA is replaced with a “screw structure (indicated by a symbol“ BS ”in the drawing)”.

  The screw structure BS adjusts the distance between the light valve LB and the first lens group LI. Since the screw structure BS forms a “second focus adjustment section” together with the intermediate member InB, the interval adjustment by the screw structure BS is performed in the optical system assembling step, and after the adjustment, the screw structure BS is fixed. Make it difficult for users to make adjustments.

  The second focus adjusting section is not limited to the intermediate members InA and InB and the screw structure BS, but may have any structure as long as it can achieve the same function as described above.

"Reference example"
A reference example will be described with reference to FIG. In addition, in order to avoid complication, the reference numerals of the respective parts are made common to those which are not considered to be confused.

  In the embodiment having the configuration shown in FIG. 10, the refractive optical system is composed of the first lens unit LI to the fourth lens unit LIV.

  In the reference example, “focusing by the floating focus method by moving the second lens unit LII and the third lens unit LIII” is performed. At this time, the fourth lens unit LIV is fixed. That is, the second lens unit LII, the third lens unit LIII, and the mechanism for displacing them constitute the “first focus structure”.

  On the other hand, the "second focus structure" is composed of the fourth lens unit LIV and a structure for moving the fourth lens unit LIV in the optical axis direction.

By moving the fourth lens unit LIV in the optical axis direction, substantially the same effect as the above-described “focusing by the entire extension” of the first and second embodiments can be obtained.
The movement of the fourth lens group LIV is performed by a cam structure different from the cam structure for performing the second and third lens groups LII and LIII, and is performed in the optical system assembling process. Do not allow easy operation.

  During the projection of the projected image, the first focus structure is used to displace the second and third lens groups LII and LIII for focusing. Since the first focus structure and the second focus structure are separate cam mechanisms from each other, the lens unit that is moved for focusing is small, and the influence of errors such as tilt that occurs during adjustment can be minimized. There are some aspects that are preferable to the total payout.

  However, when the fourth lens group LIV is moved in the direction away from the light valve LB as shown in FIG. 10, in the “optical structure using the folding mirror RM” as shown in FIGS. 8 and 9, the reflection is reflected by the folding mirror RM. It is necessary to prevent the generated light from being blocked by the fourth lens group IV on the way to the concave mirror CNM.

  A specific example of the refractive optical system used in the above-described modes 1 and 2 and the reference example will be described with reference to FIG.

  In FIGS. 11A and 11B, reference numerals 2 to 5 are “illumination optical system components”, reference numeral 1 is a “lamp light source” that is a light source, reference numeral 2 is an “integrator rod”, and reference numeral 3 is an “illumination lens”. , Reference numeral 4 indicates a “mirror”, and reference numeral 5 indicates a “curved surface mirror”. The curved mirror 5 is a “concave mirror having a spherical reflecting surface”.

  Reference numerals 6 to 10 are "projection optical system components", reference numeral 6 is a dustproof cover glass of the light valve, reference numeral 7 is the light valve main body, and reference numeral 8 is a "projection optical system".

  Reference numeral 8-1 in FIG. 11B indicates a "refractive optical system", reference numeral 9 indicates a dustproof glass for protecting "a concave mirror which is a free-form surface (concave mirror CNM in the above description)", and reference numeral 10 indicates the The "lens barrel" holding the 1st-4th lens groups is shown.

  The lens barrel 10 is engraved with three different cam grooves so that three of the four lens groups can be "moved separately". Note that "the cam groove closest to the light valve 7" has no movement amount and is irrelevant to focusing.

FIG. 12 shows a specific configuration of the refracting optical system 8-1.
The refracting optical system 8-1 has a “four-group, eleven-element” configuration as shown in FIG.
"Example 1"
One specific example of the refractive optical system having the configuration shown in FIG. 12 is designated as Example 1, and the data thereof are shown in FIGS. 13 to 15.
FIG. 13 shows the radius of curvature of each surface and the surface interval in “mm unit”, and shows the refractive index and Abbe number of the material. The aperture radius indicates the aperture radius. Further, the radius of curvature: 0.000 represents a large radius of curvature: ∞, that is, a plane.
The “eccentricity Y” is the shift amount of the optical axis of the refractive optical system POSL to the “minus side (the lower side in FIG. 5A) in the Y direction (vertical direction shown in FIG. 5A)” in “mm. Indicated in units.

  “Eccentricity α” indicates the shift amount in units of “mm” with respect to the concave mirror CNM of the projection optical system and the dustproof glass G with respect to the plane including the optical axis (Z direction) and the lateral direction of the light valve LB.

  In addition, the surface marked with "black circle" in the column of aspherical surfaces is an aspherical surface.

  In the field of surface number, “LB (0)” is the image display surface of the light valve LB (DMD), and surface numbers “1, 2” are both surfaces of the cover glass CG. The surface numbers “4, 5” are the lens surfaces on the incident side and the exit side of the lens closest to the image display surface of the refractive optical system, and these are aspherical surfaces.

In the curvature radius column, “1.0E + 18” means “1 × 10 ¹⁸ ”, and a surface having these curvature radii is a “substantially flat surface”. The value of the radius of curvature is the "paraxial radius of curvature" for aspherical surfaces.

FIG. 14A shows aspherical surface data.
The aspherical surface has paraxial curvature (reciprocal of paraxial radius of curvature): C, elliptic constant (conic constant): K, high-order aspherical coefficient: E _2j (j = 2, 3, 4, 5, 6, 7). , 8), the coordinate in the direction orthogonal to the optical axis: H, and the depth in the optical axis direction: D, a well-known equation,
^{D = CH 2 / [1 +} √ {1- (1 + K) C 2 H 2}]
+ ΣE _2j H ^2j (j = 1 to 8)
It is expressed by.

  In each of the aspherical surfaces used in the refractive optical system of Example 1, the elliptic constant: K is 0.

  FIG. 14B shows the first mirror, the second mirror (concave mirror CNM), the first and second dust-proof glass, which are based on the “vertex of the lens surface closest to the first mirror (folding mirror)”. This is data of the position of the surface, the screen distance 1 (the screen position SC (1)), and the screen distance 2 (the screen distance (2)) in the X, Y, and Z directions.

  FIG. 14C shows specific movement amount data of each lens group in “mm unit” when the screen distance is the screen distances 1 and 2.

  FIG. 15 is “mirror surface shape data” of the concave mirror CNM.

  The mirror surface shape of the concave mirror CNM is a “free curved surface”, and the paraxial radius of curvature on the optical axis is c, the conic constant is k, the higher-order coefficient is Cj (j = 2 to 72), and the distance in the direction orthogonal to the optical axis. : R, “sag amount of surface: z” parallel to the optical axis, X-direction coordinate: x, Y-direction coordinate: y in FIG.

^{z = cr 2 / [1 +} √ {1- (1 + k) c 2 r 2}]
+ ΣC _j · x ^m y ⁿ (j = 2 to 72)
In Figure 15, for example, "x ** 4 * y ** 7" to coefficient C40 represents ^{"x 4} × ^{y 7".}

The first lens group LI, which is composed of six lenses, is fixed during focusing while the image display device is in use, and the focus of the floating focus system is adjusted by the “displacement in which the interval changes” of the second to third lens groups LII to LIII. Done.
As shown in the concrete data of the projection optical system shown in FIGS. 12 to 15, the projection optical system of Example 1 is “non-telecentric on the object side”.

16 and 17 show a projector device in which the exterior OC is loaded on the projection optical system.
The light valve LB, the refraction optical system POSL, the mirror optical systems RM, CNM are incorporated in the exterior OC, and an imaging light flux is emitted through the cover glass CG to form an image on the screen SC.

  A “lens barrel mechanical structure” is set so that the “operation unit (focus lever)” of the first focus adjustment unit that performs the focus of the floating focus system is exposed to the outside of the exterior OC, and, for example, in FIG. When the screen SC is moved in the up-down (Y) direction, the focus lever of the first focus adjustment unit is moved to perform the floating focus type focusing, whereby “a suitable resolution feeling is obtained for the entire projection screen”. Can be obtained.

  The “second focus adjustment unit” is housed and fixed inside the exterior OC and is not exposed to the outside so that the user cannot easily operate the second focus adjustment unit.

  The second focus adjustment unit may be an “entire feeding mechanism that moves the entire refracting optical system in the normal direction of the light valve” when the folding mirror is not used.

  The entire feeding mechanism can be performed by screw rotation of a screw structure provided on the lens barrel that holds the refractive optical system.

  The entire extension mechanism is configured as one or more intermediate members provided between a lens barrel holding a refracting optical system and an optical housing holding a light valve, and the lens barrel and the optical housing are assembled via the intermediate member. Can be found.

  In the case of the reference example, the second focus structure is a front group focus mechanism that moves the lens group farthest from the light valve among the lens groups inside the refractive optical system in the normal direction of the light valve.

  The image display device, when projecting and displaying a projection image on a projection surface, causes light emitted from a light valve to enter a mirror optical system through a refracting optical system, and is reflected by the mirror optical system, and then reflected on the projection surface. A refracting optical system and a mirror optical system are arranged to face each other, and the projection optical system has a folding mirror for bending the optical path between the refracting optical system and the mirror optical system, and the folding mirror can adjust the installation position. Can be held by various structures.

The structure for adjusting the installation position of the folding mirror can be composed of a holding component for holding the folding mirror and one or more intermediate members arranged between the folding mirrors.
It is preferable that the curved mirror of the mirror optical system is a concave mirror, and the real image of the image display element is formed as an intermediate image on the optical path between the refractive optical system and the mirror optical system by the refractive bending optical system.
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described specific embodiments, and unless otherwise specified in the above description, the invention described in the claims. Various modifications and changes can be made within the scope of the above.
The effects described in the embodiments of the present invention are merely enumeration of the suitable effects resulting from the invention, and the effects according to the invention are not limited to "the effects described in the embodiments".

LB light valve
LI first lens system
LII Second lens system
LIII Third lens system
LIV theme 4 lens system
RM folding mirror
CNM curved mirror
InA intermediate member
InB intermediate member
SC screen

JP, 2009-251457, A JP 2009-229738 A JP 2008-165187 A

Optical Technology Contact Vol. 39, No. 9 (2001)

The method for manufacturing a projection optical system of the present invention includes, in order from the object side, a refracting optical system including a plurality of lens groups, and a mirror optical system having a curved mirror. While maintaining a distance between the conjugate surface side conjugate surface and the object side conjugate surface, a part of the lens group in the refracting optical system is moved in the optical axis direction of the refracting optical system to display the top and bottom of the display screen. A first focus adjustment unit that corrects different focus adjustment amounts, and a first focus adjustment unit that maintains a distance between the object-side conjugate surface-side lens surface of the dioptric system and the object-side conjugate surface at a predetermined distance. A method of manufacturing a projection optical system, comprising: a second focus adjusting unit; and enlarging and projecting an image of an object, wherein the second focus adjusting unit moves a lens of the refractive optical system. The conjugate surface side of the refraction optical system closest to the object side After performing focus adjustment for adjusting the focus of the entire display screen by changing the distance between the lens surface and the conjugate surface on the object side, the lens surface on the conjugate surface side of the most object side of the refractive optical system and the object It is characterized in that the predetermined distance from the side conjugate surface is fixed.

Claims (9)

In order from the object side, a refracting optical system including a plurality of lens groups and a mirror optical system having a curved mirror are arranged, and a lens surface on the conjugate surface side of the refraction optical system closest to the object side and the object side. A part of the lens group in the refracting optical system is moved in the normal direction of the conjugate plane on the object side while maintaining the distance from the conjugate plane to correct different focus adjustment amounts on the upper and lower sides of the display screen. And a second focus adjusting unit for maintaining a distance between a lens surface on the conjugate surface side closest to the object side of the refracting optical system and the conjugate surface on the object side at a predetermined distance. A method for manufacturing a projection optical system for enlarging and projecting an image of an object, comprising:
The second focus adjustment unit moves the lens of the refracting optical system to change and display the distance between the lens surface on the object-side conjugate surface side of the refracting optical system and the object-side conjugate surface. After performing focus adjustment for adjusting the focus of the entire screen, the predetermined distance between the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refractive optical system is fixed. Method of manufacturing projection optical system. The method for manufacturing a projection optical system according to claim 1,
A method of manufacturing a projection optical system, characterized in that a focus structure is fixed by a second focus adjusting section so that the predetermined distance does not change. The method for manufacturing a projection optical system according to claim 1,
The said 2nd focus adjustment part is a manufacturing method of the projection optical system characterized by moving the whole refractive optical system to the normal direction of the conjugate plane by the side of an object. The method for manufacturing a projection optical system according to claim 3,
The method for manufacturing a projection optical system, wherein the second focus adjustment unit has a screw structure provided on a lens barrel that holds a refractive optical system. The method for manufacturing a projection optical system according to any one of claims 1 to 4,
A method of manufacturing a projection optical system, comprising: a folding mirror for folding an optical path between a refracting optical system and a mirror optical system, the folding mirror being held by a structure whose installation position can be adjusted. The method for manufacturing a projection optical system according to claim 5,
The method for manufacturing a projection optical system, wherein the structure for adjusting the installation position of the folding mirror is composed of a holding component for holding the folding mirror and one or more intermediate members arranged between the folding mirrors. The method for manufacturing a projection optical system according to claim 1, wherein
The curved mirror of the mirror optical system is a concave mirror, and a real image of an object is formed as an intermediate image on the optical path between the refractive optical system and the mirror optical system by the refractive optical system, which is a method for manufacturing a projection optical system. A refracting optical system including a plurality of lens groups and a mirror optical system having a curved mirror are arranged in order from the object side, and a distance between a lens surface closest to the image display element of the refracting optical system and the image display element. A first focus adjustment unit that moves a part of the lens group in the refractive optical system in the normal direction of the image display element while maintaining the above, to correct different focus adjustment amounts on the upper and lower sides of the display screen, A second focus adjusting unit for maintaining a distance between the object-side conjugate surface-side lens surface of the refraction optical system closest to the object-side conjugate surface, and displaying on the image display device. A method for manufacturing an image display device having a projection optical system for enlarging and projecting the formed image,
The second focus adjustment unit moves the lens of the refracting optical system to change and display the distance between the lens surface on the object-side conjugate surface side of the refracting optical system and the object-side conjugate surface. After performing focus adjustment for adjusting the focus of the entire screen, the predetermined distance between the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refractive optical system is fixed. Image display device manufacturing method. The method for manufacturing an image display device according to claim 8,
The second focus adjustment unit is at least one intermediate member provided between a lens barrel holding the refraction optical system and an optical housing holding the image display element. Production method.

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