JP7067572B2 - Manufacturing method of projection optical system and manufacturing method of image display device - Google Patents

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 bulb will be described with reference to FIG.

FIG. 1 shows an explanatory diagram of an optical arrangement of a “projector device” that is generally used 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 bulb 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 bulb LB.

The integrator rod IR, the illumination lens LN, the mirror M, and the curved mirror CM constitute 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 inlet portion to the outlet portion while being reflected by the mirror surface.

The projection optical system POS projects the reflected light from the light bulb LB toward the projected surface such as a screen, and magnifies and forms an image of the “image displayed on the light bulb LB” on the projected surface.

The light bulb LB is a "DMD (Digital Micromirror Device)" in this example, and is formed by arranging minute mirrors in an array. Each micromirror can change its normal direction independently of each other, for example, in the "± 12 degree range".

The light emitted from the lamp LP is reflected by the reflector RF and focused on the inlet of the integrator rod IR. The light incident from the inlet portion is guided while being repeatedly reflected in the integrator rod IR, and is emitted from the outlet portion as light having a uniform illuminance "equalized uneven illuminance".

The light emitted from the integrator rod IR irradiates the light valve LB via an illumination optical system including an illumination lens LN, a mirror M, and a curved mirror CM.

The illumination lens LN, the mirror M, and the curved mirror CM of the illumination optical system use the emitted light at the outlet of the integrator rod IR as a "surface light source having uniform illuminance with uneven light intensity", and image of this surface light source. Formed on the light valve LB. That is, the light bulb LB is irradiated with illumination light having a uniform illuminance.

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

An image can be displayed on the light bulb LB by adjusting the inclination of each minute mirror according to the pixels of the image to be projected and imaged on the projected surface. The image displayed in this way is called a "display image".

When an image is displayed on the light valve LB and the light valve LB is irradiated with the illumination light in this way, the reflected light for each minute mirror incident on the projection optical system POS is converted into an imaged light beam by the projection optical system POS and projected. It is projected onto the surface as an enlarged image of the above image to form an image. The image formed on the projected surface in this way is called a "projected image".

Since the light bulb LB is irradiated with "light having a uniform illuminance distribution", the projected image on the projected surface, which is an enlarged image of the displayed display image, also has a uniform illuminance distribution. In this way, a "digital image" can be displayed on the projected surface.

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

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

"Focusing" is necessary to form a projected image on the projected surface.
In the "normal projector device" shown in FIG. 2A, the projection optical system POS1 is "coaxial rotational symmetry", and the focusing of the projected image on the screen SC which is the projected surface is the entire projection optical system POS1. The "whole extension method" that focuses by moving the lens and the focusing method that moves the focus group with one or more lenses in the lens system are common. In each of the figures below FIG. 2, the optical axis of the lens system portion that is coaxially axially rotationally symmetric of the projection optical system is represented by the reference numeral “AX”.

"The refraction optical system POSL1 composed of a plurality of lenses and the mirror optical system POSM1 composed of non-coaxial reflecting surfaces that do not share an optical axis with the refraction optical system POSL1" shown in FIG. 2B (FIG. 2). In the example of the above, a projector device using a projection optical system composed of a single concave mirror) is known and is becoming widespread.

Such a projector device has been proposed and is being implemented that enables projection at a closer distance (ultra-closest distance) than before.

When "projecting an image at a close distance or a very close distance" to 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, in general, as shown in FIG. 2, the center of the image display element LB (DMD in this case) is displaced from the optical axis AX of the projection optical system and arranged eccentrically.
Then, in order to "widen the performance guarantee range of the projection optical system", the image quality is maintained by using a wide-angle lens for the projection optical system.
However, there is a limit to widening the angle of the projection optical system by the co-axis rotationally symmetric lens system, and in order to project the projected image from the "super close position closer to the screen SC", the mirror optical system "gains the optical path". There is a need.

Projection by lens system There is also a "diagonal projection" method in which the optical path of the optical system is folded back by a plane mirror, the optical axis of the projection optical system is tilted diagonally with respect to the screen, and projection is performed at a short distance. 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 constituting the mirror optical system POSM1 to a "free curved surface".
Non-Patent Document 1 describes in detail such "correction of trapezoidal distortion by a mirror having a free curved surface".

In a projector device as shown in FIG. 2B, which uses a refraction optical system POSL1 and a mirror optical system POSM1 and uses a "free curved mirror" for the mirror optical system POSM1 to correct trapezoidal distortion, the above-mentioned " A "floating focus method" can be considered as a focusing method suitable for performing "focusing".

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

In particular, focusing at close range or ultra close range is called the floating focus method because it "moves multiple lens groups like a floating tree to focus", and in particular, "interchangeable lens for single-lens reflex cameras". Widely used in.

Focusing using the full extension method or "single lens or lens group" tends to lack correction of trapezoidal distortion when a projected image is projected from a close distance to the screen SC, and correction of curvature of field tends to be insufficient. However, there is a problem that the center and the periphery of the display screen are out of focus.

In the floating focus method, the distortion of the image generated when the projected image is projected from a close distance to the screen SC is mainly corrected by the "non-coaxial curved mirror", so that the trapezoidal distortion can be corrected. It is also possible to satisfactorily correct the curvature of field.

A more specific explanation will be given.
FIG. 3A shows a projector device for “oblique projection”. For the sake of simplicity in the illustration, the plane mirror that folds back the optical path is not shown.

The projected 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 figure of FIG. 3 (b). The projected image projected above has a "trapezoidal shape" as shown in the lower figure of FIG. 3 (b).

FIG. 4A shows a projection type projector device using a projection optical system composed of a refraction 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 figure of FIG. 4 (b), and the real image of this image display surface is converted into an intermediate image Im0 by the refraction optical system POSL1. As a result, an image is formed between the refraction optical system POSL1 and the mirror optical system POSM1, and a projection image with the intermediate image Im0 as an object image is image-projected on the screen SC by the mirror optical system POSM1.

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

In the projector device of FIG. 4, in order to display a "smaller projected image" on the screen SC, the screen SC is oriented in the Z direction (from the position of FIG. 4A) as shown in FIG. 5A. Consider a case where the image is moved to the right side and the focus is adjusted by "total extension in the Z direction" of the refractive optics 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 optics system POSL1, the shape of the intermediate image Im0 is as shown in the middle diagram of FIG. 5 (b) in FIG. 4 (b). Similar to the case of the lower figure, the projected image on the screen SC causes "trapezoidal distortion in which the upper side is shortened" as shown in the lower figure of FIG. 5 (b).

This phenomenon will be described in more detail with reference to FIGS. 6 and below.
FIG. 6A shows a state in which FIG. 4A is 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 the light directed upward in the Y direction and downward in the Y direction of the display screen on the screen SC are different in the XZ cross section.

FIG. 6 (c) is the shape of the projected image when proper projection is performed as shown in FIG. 6 (a), and is a rectangular shape.

When the screen SC is moved as shown in FIG. 5A, the positions in the X direction to reach the screen SC differ between the top and bottom 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” occurs.

When the distance between the light valve and the bending optics (distance in the normal direction of the light valve) is appropriate, the "floating focus method" is very effective for correcting trapezoidal distortion and correcting curvature of field as described above. be.

In focusing by the floating focus method, the curvature of field correction acts strongly. Therefore, for example, as shown in FIG. 7, the screen SC is set to the screen position SC (1) (the state of (a) in FIG. 4). From the screen position SC (2) (the state shown in FIG. 5A) to "when the focus adjustment amount is significantly different between the top and bottom of the display screen" as when approaching the curved mirror POSM1. It is valid.

However, focusing by the floating focus method does not work effectively when "the amount of focus adjustment to be adjusted is the same" on the entire display screen. In such a case, "focusing by the whole extension method or the front group extension method" Is valid.

Various methods have been widely known for focusing on a projector device (for example, Patent Documents 1 to 3).

Focusing by the floating focus method mainly has the function of correcting the "focus shift between the center and the periphery" of the display screen, but "variation in the distance between the refraction optical system and the light valve" and "variation in the focal length of the refraction optical system". It is not suitable for correcting the case where the focus of the entire projected image is "out of focus" due to "".

The present invention has been made in view of the above-mentioned circumstances, and has a refraction optical system and a mirror optical system, and has a function of correcting "a different focus adjustment amount between the top and bottom" of the display screen and "the entire projected image". The subject is to provide a method for manufacturing a projection optical system having a function of correcting "out-of-focus".

In the method for manufacturing a projection optical system of the present invention, a refractive 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 the most of the object side of the refractive optical system. While maintaining the distance between the lens surface on the conjugate surface side and the conjugate surface on the object side, some lens groups in the refraction optical system are moved in the optical axis direction of the refraction optical system to move the lens group to the top and bottom of the display screen. The distance between the first focus adjustment unit that corrects different focus adjustment amounts, the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refraction optical system , and the lens surface and the curved surface. It is a method of manufacturing a projection optical system having a second focus adjusting unit that maintains a distance from a mirror at a predetermined distance and magnifying and projecting an image of an object by the second focus adjusting unit. Adjust the focus of the entire display screen by changing the distance between the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refraction optical system , and the distance between the lens surface and the curved mirror. After performing the focus adjustment, 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 refraction optical system is fixed.

As described above, the projection optical system manufactured by the manufacturing method of the present invention has two focus adjusting units that are separate from each other, that is, a first focus adjusting unit and a second focus adjusting unit. When the real image of the image display element is projected onto the projected surface to perform focusing, the floating focus method can be used for focusing.

In addition, the second focus adjustment unit changes the distance between 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, and "variation in the distance between the refraction optical system and the light valve". And "out-of-focus of the entire projected image" caused by "variation in the focal distance of the refraction optical system" can be effectively corrected, and the focus of the entire projected image can be adjusted.

Since 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, the second focus adjustment unit is fixed when the first focus adjustment unit is operated. ing.

It is a figure for demonstrating a general projector apparatus as an image display apparatus. It is a figure for demonstrating the focusing of a projected image. It is a figure for demonstrating the trapezoidal distortion of a projected image. It is a figure for demonstrating the correction of trapezoidal distortion. It is a figure for demonstrating the case where the correction of trapezoidal distortion is insufficient in an image projection apparatus using a mirror optical system. It is a figure for demonstrating the case where the correction of trapezoidal distortion is insufficient in an image projection apparatus using a mirror optical system. It is a figure for demonstrating the case where a screen position changes in an image projection apparatus using a mirror optical system. It is a figure for demonstrating one example of embodiment. It is a figure for demonstrating another example of embodiment. It is a figure for demonstrating a reference example . It is a figure for demonstrating a specific example of the refraction optical system used in embodiment . It is a figure which shows an example of the specific structure of a refraction optical system. It is a figure which shows the data of the refraction optical system part of the projection optical system of Example 1. FIG. It is a figure which shows the data of Example 1. FIG. It is a figure which shows the data of the mirror surface shape of the concave mirror in Example 1. FIG. It is a figure for demonstrating the projector apparatus which loaded the exterior OC in the projection optical system. It is a figure for demonstrating the projector apparatus which loaded the exterior OC in 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 a light bulb which is an image display element, but the image display element in the image display device manufactured by the manufacturing method of the present invention is, of course, not limited to DMD.

That is, in the image display device manufactured by the manufacturing method of the present invention, light bulbs other than DMD, for example, various known light bulbs such as LD panel and LCOS panel can be used.

Further, in order to avoid complication of the drawing, in the drawings used for the explanation of the following examples, the lamp light source which is a light source and the illumination optical system which guides the illumination light from the lamp light source to the light valve and irradiates the light valve are shown. Omit.

Actually, the illumination light from the lamp light source LS as shown in FIG. 1, the integrator rod IR, the illumination lens LN, the mirror M, and the curved mirror CM are illumination optical systems using curved mirrors, and the light valve LB (DMD). ) Is expected 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 ones are used depending on 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 bulb LB is a DMD and is held in 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 the “refractive optical system” of the projection optical system are arranged in the lens barrel CL.
In the first embodiment, the "refractive optical system" has four lens groups, that is, the first lens group LI, the second lens group LII, the third lens group LIII, and the fourth lens group LIV from the light bulb LB side. It is configured.

Further, the reference numeral RM indicates a “folded mirror”, and the reference numeral CNM indicates a concave mirror forming a “mirror optical system”.

When the illumination light from a light source (not shown) is applied to the image display surface of the DMD which is a light valve LB by an illumination optical system (not shown), the reflected light by the image display surface is intensity-modulated by the display image displayed on the DMD. Then, it is incident on the "reflecting optical system" of the projection optical system.

The luminous flux emitted from the refraction optical system is reflected by the folded mirror RM, and when reflected by the concave mirror CNM, it becomes an imaged luminous flux, heads toward a projected surface (screen) (not shown), and displays an image on the projected surface. An enlarged projection image is imaged.

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

In such an "optical system via the folded mirror RM", the "optical path between the refracting optical system and the concave mirror CNM " is displayed on the "display image" so that the degree of diffusion of the light reflected by the folded mirror RM can be reduced. It is preferable to reduce the light beam once by forming an image of the "real image" as an intermediate image.

Focusing by focusing will be explained.
Although not shown in FIG. 8, when the position of the screen is brought closer from the screen position SC (1) in FIG. 7 as in the screen position SC (2), it differs between the “top and bottom” of the projected image. In order to correct the amount of focus adjustment, focus is performed using the floating focus method.
In the first embodiment, of the four lens groups constituting the refractive optical system, the second lens group LII and the third lens group LIII are moved in the optical axis direction to perform focusing.

Although FIG. 8 does not show the structure of the lens barrel CL in detail, in order to move the second lens group LII and the third lens group LIII, for example, a cam groove is formed in the lens barrel CL and the second lens group is formed. The second lens group LII and the third lens group LIII are different from each other by attaching a pin matching 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. It can be moved in the direction.

Here, the lens barrel CL is treated as if it were a single component to simplify the explanation, but in reality, it is common to adopt a "more complicated configuration" consisting of a plurality of components.

This cam mechanism is referred to as a "first focus adjusting unit".

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 bulb LB of FIG. 8 and the first lens group LI varies according to the “dimensional variation”.
Further, in the first form, if a plurality of lenses of the refraction optical system composed of the first to fourth lens groups LI to LIVE and a plurality of concave mirror CNMs are manufactured, there is "shape variation" in each, and in particular, " The "focal length of the refraction optical system" varies, and the "optimal distance" between the light valve LB and the first lens group LI varies.

Even if there are these two types of "variation", the "intermediate member InA" is arranged so that the distance between the light bulb LB and the first lens group LI can be optimized.

As the intermediate member InA, for example, a plurality of thin plates having a thickness of about 0.1 mm are used, and the total thickness of the intermediate member InA is changed by changing the number of thin plates interposed between the optical housing HS and the lens barrel CL. Can be adjusted. In this way, the distance between the light bulb 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 such as aluminum having different thicknesses in units of 0.1 mm are prepared as intermediate members InA, and "aluminum plate having an optimum thickness" is prepared for each combination of the optical housing HS and the refractive optics system. If you select and insert the light valve LB, the distance between the light valve LB and the first lens group LI can be adjusted in units of 0.1 mm.

After adjusting the positional relationship between the optical housing HS and the lens barrel CL with the intermediate member InA, it is preferable to "fix each other with screws or the like" in order to fix these positional relationships.

As described above, when the positional relationship between the light bulb LB and the first lens group LI is optimized in the intermediate member InA, the positional relationship between the fourth lens group LIV and the concave mirror CNM is "initially assembled" by this optimization operation. It deviates from the "relationship of".

In order to correct this, the optical path length between the fourth lens group LIV and the concave mirror CNM is adjusted by using the intermediate member InB interposed between the folded mirror RM and the holder HL.

As for the intermediate member InB, if a plurality of thin plates or aluminum plates having different thicknesses are used as in the intermediate member InA, the optical path length can be easily adjusted with high accuracy.

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

The intermediate members InA and InB described above form a "second focus adjusting unit".

Since it can be adjusted by simply inserting 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 are close to the light valve LB and have heat, are in direct contact with each other. By not doing so, heat is less likely to be transferred 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 the first embodiment has the first and second focus adjusting units as described above.
In the first focus adjustment unit, when the distance between the projected surface and the concave mirror CNM is changed, the second lens group LII and the third lens group LIII in the refraction optical system are "displaced by different movement amounts". Focusing is performed using 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, the positional relationship between the light valve, the refraction optical system, and the concave mirror (mirror optical system) is made appropriate in the reference state. Make sure that the projected image is in focus. Then, after adjusting the positional relationship, the second focus adjusting unit is fixed.

"Embodiment 2"
The second embodiment will be described with reference to FIG.

The second form is a modification of the first form described above, and the intermediate member in the first form is the "structure for adjusting the distance between the light bulb LB and the first lens group LI" in the second focus adjusting part. This is an example in which "screw structure (indicated by the symbol" BS "in the figure)" is used instead of InA.

The distance between the light bulb LB and the first lens group LI is adjusted by the screw structure BS. Since the screw structure BS forms a "second focus adjustment unit" together with the intermediate member InB, the spacing adjustment by the screw structure BS is performed in the optical system assembly process, and after the adjustment, the screw structure BS is fixed. Make adjustments by the user not easy.

The second focus adjusting unit is not limited to the intermediate members InA and InB, the screw structure BS, and the like, and may have any structure as long as the same functions as described above can be achieved.

"Reference example"
A reference example will be described with reference to FIG. In addition, in order to avoid congestion, the codes of each part will be shared for those that are not considered to be confused.

In the form of the reference example shown in FIG. 10, the refraction optical system is composed of the first lens group LI to the fourth lens group LIVE.

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

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

By moving the fourth lens group LIV in the optical axis direction, substantially the same effect as the "focusing by total extension" of the above-mentioned first and second forms can be obtained.
The movement of the 4th lens group LIV is performed by a cam structure different from the cam structure in which the 2nd and 3rd lens groups LII and LIII are performed, and is carried out in the process of assembling the optical system. Make it difficult to operate.

During the projection of the projected image, the second and third lens groups LII and LIII are displaced and focused by the first focus structure. Since the first focus structure and the second focus structure have cam mechanisms that are separate from each other, the lens unit to be moved for focusing is small, and the influence of errors such as tilt generated by adjustment can be suppressed to a small extent. There is a more preferable aspect than the whole feeding.

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

Specific examples of the refractive optics system used in the above-described first and second forms and the reference example will be described with reference to FIGS. 11 and 11 and below.

In FIGS. 11 (a) and 11 (b), reference numerals 2 to 5 are “parts of the illumination optical system”, reference numeral 1 is a “lamp light source” which is a light source, reference numeral 2 is an “integrator rod”, and reference numeral 3 is an “illuminating 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 “parts of the projection optical system”, reference numeral 6 is a dustproof cover glass of the light bulb, reference numeral 7 is a light bulb 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 dust-proof glass that protects a “concave mirror having a free curved surface (concave mirror CNM in the above description)”, and reference numeral 10 indicates a first. The "lens barrel" holding the 1st to 4th lens groups is shown.

The lens barrel 10 is carved with three different cam grooves so that three of the four lens groups can "move separately". Since the amount of movement of the "cam groove closest to the light valve 7" is 0, it is irrelevant to the focus.

A specific configuration of the refractive optics system 8-1 is shown in FIG.
As shown in FIG. 12, the refractive optics system 8-1 has a “4 group 11 elements” configuration.
"Example 1"
An example of a specific example of the refractive optics system shown in FIG. 12 is taken as Example 1, and the data thereof are shown in FIGS. 13 to 15.
FIG. 13 shows the radius of curvature and the surface spacing of each surface in "mm units", and shows the refractive index and Abbe number of the material. For the aperture stop, the opening radius is shown. Further, the radius of curvature: 0.000 represents a large radius of curvature: ∞, that is, a plane.
"Eccentricity Y" is the amount of shift of the optical axis of the refractive optics system POSL to the "minus side (lower side of FIG. 5A)" in the "Y direction (vertical direction shown in FIG. 5A)" by "mm". Shown in units.

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

In addition, the surface with a "black circle" in the aspherical surface column is an aspherical surface.

In the surface number column, "LB (0)" is an image display surface of the light bulb LB (DMD), and surface numbers "1, 2" are both sides of the cover glass CG. The surface numbers "4, 5" are lens surfaces on the incident side and the ejection side of the lens on the most image display surface side of the refractive optical system, and both of them are aspherical surfaces.

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

FIG. 14A is aspherical data.
The aspherical surface has a near-axis curvature (inverse number of the near-axis curvature radius): C, an elliptical constant (conic constant): K, and a higher-order aspherical coefficient: E _2j (j = 2, 3, 4, 5, 6, 7). , 8), Coordinates in the direction orthogonal to the optical axis: H, Depth in the optical axis direction: D, a well-known formula,
D = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
+ ΣE _2j H ^2j (j = 1-8)
It is expressed by.

In the aspherical surface used in the refractive optics system of Example 1, the elliptic constant: K is 0.

FIG. 14B shows the first mirror, the second mirror (concave mirror CNM), and the first and second dustproof glasses based on the “plane apex of the lens surface closest to the first mirror (folded mirror)”. It is the data of the positions in the X, Y, and Z directions of the surface, the screen distance 1 (the screen position SC (1)), and the screen distance 2 (the screen distance (2)).

FIG. 14C shows specific movement amount data of each lens group in "mm units" 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", the near-axis radius of curvature on the optical axis: c, the conic constant: k, the higher-order coefficient: Cj (j = 2-72), and the distance in the direction perpendicular to the optical axis. : R, "Sag amount of surface: z" parallel to the optical axis, coordinates in the X direction: x, coordinates in the Y direction: y in FIG. 5 are given by the following equations.

z = cr ² / [1 + √ {1- (1 + k) c ² r ² }]
＋ ΣC _j・ xmy ⁿ (j = ^2-72 )
In FIG. 15, for example, “x ** 4 * y ** 7” having C40 as a coefficient represents “x ⁴ × y ⁷ ”.

The 6-lens first lens group LI is fixed at the time of focusing while the image display device is in use, and the floating focus method focusing is performed by the "displacement in which the interval changes" of the second to third lens groups LII to LIII. It will be done.
As shown in the specific data of the projection optical system shown in FIGS. 12 to 15, the projection optical system of the first embodiment is “non-telecentric on the object side”.

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

The "lens barrel mechanical structure" is set so that the "operation unit (focus lever)" of the first focus adjustment unit that performs focusing by the floating focus method is exposed to the outside of the exterior OC. For example, in FIG. When the screen SC is moved up and down (Y), if the focus of the floating focus method is performed by moving the focus lever of the first focus adjustment unit, "a suitable resolution for the entire projection screen". Can be obtained.

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

The second focus adjusting unit can be a "whole extension mechanism for moving the entire refractive optics system in the normal direction of the light bulb" when the folded mirror is not used.

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

The entire feeding mechanism is configured as one or more intermediate members provided between the lens barrel holding the refraction optical system and the optical housing holding the light bulb, 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 bulb among the lens groups inside the refractive optical system in the normal direction of the light bulb.

When the image display device projects and displays a projected image on the projected surface, the light emitted from the light valve enters the mirror optical system via the bending optical system, is reflected by the mirror optical system, and then is reflected on the projected surface. Folded optics and mirror optics are arranged so as to face each other, and the projection optics have a fold-back mirror for optical path bending between the fold-back optics and the mirror optics, and the fold-back mirror can adjust the installation position. Can be held in a similar structure.

The structure for adjusting the installation position of the folded mirror can be composed of a holding component for holding the folded mirror and one or more intermediate members arranged between the folded mirrors.
The curved mirror of the mirror optical system is a concave mirror, and it is preferable that the real image of the image display element is formed as an intermediate image in the optical path between the refraction optical system and the mirror optical system by the refraction bending optical system.
Although the preferred embodiment of the invention has been described above, the present invention is not limited to the above-mentioned specific embodiment, and the invention described in the claims is not particularly limited in the above description. Various modifications and changes are possible within the scope of the above.
The effects described in the embodiments of the present invention merely list suitable effects arising from the invention, and the effects according to the invention are not limited to those described in the embodiments.

LB light bulb
LI 1st lens system
LII 2nd lens system
LIII 3rd lens system
LIV Theme 4 Lens system
RM folded mirror
CNM curved mirror
InA intermediate member
InB intermediate member
SC screen

JP-A-2009-251457 JP-A-2009-229738 Japanese Patent Application Laid-Open No. 2008-165187

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

Claims (8)

A refraction 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 the lens surface on the conjugate surface side of the object side and the lens surface on the object side of the refraction optical system are arranged. First, a part of the lens group in the refraction optical system is moved in the optical axis direction of the refraction optical system while maintaining a distance from the conjugate surface to correct different focus adjustment amounts on the upper and lower sides of the display screen. The distance between the focus adjusting unit and the lens surface on the conjugate surface side of the object side of the refraction optical system and the conjugate surface on the object side, and the distance between the lens surface and the curved mirror are maintained at predetermined distances. It is a method of manufacturing a projection optical system having a second focus adjustment unit and magnifying and projecting an image of an object.
The second focus adjusting unit changes the distance between the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refraction optical system, and the distance between the lens surface and the curved mirror. After performing focus adjustment to adjust the focus of the entire display 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 refraction optical system is fixed. A characteristic method for manufacturing a projection optical system. In the method for manufacturing a projection optical system according to claim 1,
A method for manufacturing a projection optical system, which comprises fixing a focus structure by a second focus adjusting unit so that the predetermined distance does not change. In the method for manufacturing a projection optical system according to claim 1 or 2.
The second focus adjusting unit is a structure that moves the entire bending optical system in the normal direction of the conjugate surface on the object side, and a folding back for optical path bending provided between the bending optical system and the curved mirror. It has a mirror and a structure in which the installation position of the folded mirror can be adjusted, and the entire refractive optics system is moved in the normal direction of the conjugate surface on the object side, and the installed position of the folded mirror is adjusted. , The projection optical system characterized in that the distance between the lens surface on the conjugate surface side of the object side and the conjugate surface on the object side of the refraction optical system and the distance between the lens surface and the curved mirror are changed. Manufacturing method. In the method for manufacturing a projection optical system according to claim 3.
The structure for moving the entire refraction optical system of the second focus adjustment unit in the normal direction of the conjugate surface on the object side is characterized by a screw structure provided on the lens barrel holding the refraction optical system. A method for manufacturing a projection optical system. In the method for manufacturing a projection optical system according to claim 3 or 4 .
The structure for adjusting the installation position of the folded mirror of the second focus adjusting unit is composed of a holding component for holding the folded mirror and one or more intermediate members arranged between the folded mirrors. A method for manufacturing a projection optical system. In the method for manufacturing a projection optical system according to any one of claims 1 to 5 .
The curved mirror of the mirror optical system is a concave mirror, and the projection optical system is characterized in that a real image of an object is formed as an intermediate image in an optical path between the refractive optics system and the mirror optical system by the refractive optics system. Manufacturing method. In order from the object side, a refraction optical system including a plurality of lens groups and mirror optics having a curved mirror.
The system is arranged, and the lens surface on the most image display element side of the refraction optical system and the image display element
A part of the lens group in the dioptric optical system is moved in the optical axis direction of the dioptric optical system while maintaining the distance of.
The distance between the first focus adjustment unit, which is moved to correct different focus adjustment amounts on the top and bottom of the display screen, and the lens surface on the conjugate surface side of the object side of the refraction optical system and the conjugate surface on the object side. , And a second focus adjusting unit that maintains the distance between the lens surface and the curved mirror at a predetermined distance, and has a projection optical system that magnifies and projects an image displayed on the image display element. It is a method of manufacturing an image display device.
By the second focus adjustment unit, the refraction optical system is located on the conjugate surface side of the object side.
The distance between the lens surface and the conjugate surface on the object side, and the distance between the lens surface and the curved mirror.
After performing focus adjustment to change and adjust the focus of the entire display screen, the refraction optical system
A method for manufacturing an image display device, which comprises fixing the predetermined distance between the lens surface on the conjugate surface side of the object and the conjugate surface on the object side . In the method for manufacturing an image display device according to claim 7 ,
The second focus adjusting unit has a folding mirror for bending an optical path provided between the bending optical system and the curved mirror, and has a lens barrel that holds the bending optical system and the image display element. At least one intermediate member provided between the optical housings to be held changes the distance between the lens surface on the conjugate surface side of the most object side of the refractive optics system and the conjugate surface on the object side, and the installation position of the folded mirror. A method of manufacturing an image display device, which comprises changing the image display device by at least one other intermediate member .

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