JP2001083387A - Lens barrel and projection display device provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain lens barrel structure which is used in a projection lens and facilitates the adjustment of magnification, of focusing and of image quality and is inexpensive, accurate and excellent in performance. SOLUTION: In this lens barrel, a 1st group lens barrel 2 having a lens group for image quality adjustment is helicoid-coupled with the front part of a fixed lens barrel 3 holding a part of the lens group for image quality adjustment, a moving ring 4 is fitted to the inner periphery side of the lens barrel 3 and moves in the optical axis direction along the cam lift 3b of the barrel 3, and a 2nd group lens barrel 5, which can be adjustably fixed to the inside of the moving ring 4 by machine screws, is fixed after adjusting magnification through moving the barrel 5 in the optical axis direction by passing an eccentric tool or the like through the guide hole 4a of the ring 4 from the notched part 3d of the lens barrel 3 so that the magnification matches with designated picture size at a zoom end position. Then a 3rd group lens barrel 6 being a lens group for focusing fitted to the rear end of the lens barrel 3 is focused by turning an operation part 6b, and finally the lens barrel 2 is turned to adjust image quality and fixed at the best position by a machine screw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a liquid crystal projector and a projection display device thereof.

[0002]

2. Description of the Related Art Conventionally, a projection lens of a liquid crystal projector is roughly classified into a rear lens and a front lens. Conventionally, a rear projection lens is a single focus projection lens, and a lens barrel structure having only a focus mechanism has been generally used. The general configuration of the front projection lens is similar to that of a multi-group optical system zoom lens, in which the angle of view adjustment means and image quality adjustment are the same as those of a shooting lens determined by the precision of the components and the cam lift shape, and the zoom magnification is Adjustment is performed, and image quality is adjusted by focusing.

[0003]

However, in the conventional lens barrel structures of the rear projection lens and the front projection lens, the optical performance is determined by the design value, the general lens barrel configuration, and the component accuracy. As a result, focus adjustment by focus and magnification adjustment by zooming were performed, but each adjustment with high precision and a lens barrel structure with high image quality could not be performed.

An object of the present invention is to provide a highly accurate and optimal lens barrel structure having a magnification adjustment, a focus adjustment, and a high image quality adjustment mechanism in view of the above-mentioned problems of the conventional example.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention first adjusts the magnification by two groups of lens barrels.
Next, focus adjustment is performed by three groups, and finally image quality is adjusted by one group.

[0006]

According to the first aspect of the present invention, a lens barrel structure includes a first lens unit for adjusting a first image quality, a second lens barrel moving in the optical axis direction, and a second lens barrel. A zoom lens optical system composed of a third group including a group, a focus group for adjusting the second image quality, and a fixed lens barrel holding and engaging each group and having a flange. , A highly accurate screen size and the best image position can be obtained. According to the second aspect of the present invention, since the fixed lens barrel and the second lens unit have moving means for adjusting the magnification in the optical axis direction, the magnification can be easily and accurately adjusted. According to the third aspect of the present invention, the image quality can be easily and accurately adjusted by holding a part of the lenses of the first lens group in front of the fixed lens barrel.

According to a fourth aspect of the present invention, a guide groove for zooming and a transmission member for transmitting driving are rotatable at a fixed position on the outer periphery of the fixed lens barrel, and end detection means is provided.
The system can be reliably and appropriately controlled by the zoom signal. According to a fifth aspect of the present invention, the fixed barrel has a moving cam lift for zoom, and the moving cam lift for zoom has a moving amount of 0 mm in the optical axis direction at both ends of the zoom in consideration of absorption of a manufacturing error.
By having the flat lift and the end detecting means, an appropriate zoom operation can be performed. According to a sixth aspect of the present invention, there is provided a projection display device having the lens barrel according to any one of the first to fifth aspects, so that magnification adjustment and image quality adjustment can be performed even after the lens barrel is incorporated in the display device. Easy.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a zoom lens barrel of the present embodiment, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a configuration diagram of a liquid crystal projector using the zoom lens barrel. In FIG. 1, reference numeral 1 denotes a first-group lens barrel which holds a part of an image quality adjusting lens group L1 as a first-group lens. Form a female helicoid 1a. Reference numeral 3 denotes a fixed lens barrel, which is a male helicoid 3a formed on the outer periphery of the tip.
A female helicoid 1a of the group lens barrel 1 is helicoidally coupled, and a distal end thereof holds a lens which is a part of the image quality adjusting lens group L1, and a zoom moving cam lift 3b is formed at an inner diameter thereof. ing. Reference numeral 4 denotes a movable ring which is fitted on the inner diameter of the fixed lens barrel 3 and is movable in the optical axis direction along the zoom movable cam lift 3b. Further, the zoom moving cam lift 3b has a moving amount of 0 m in the optical axis direction at both ends of the zoom in consideration of manufacturing error absorption.
m with a flat lift.

Reference numeral 5 denotes a second group lens barrel which holds the second group lens L2, is fitted to the inner diameter of the moving ring 4, and is fixed to the moving ring 4 by a plurality of screws 13. Reference numeral 6 denotes a third-group barrel, which holds a third-group lens L3 as a focusing lens, and is fitted to the rear end inner diameter of the fixed barrel 3;
A plurality of cam leads 6a formed on the outer periphery are engaged with projections 3c provided on the inner diameter of the fixed lens barrel 3. 7
Is a zoom gear having a gear on its outer periphery, and the fixed barrel 3
And a guide groove 7a for moving the movable ring 4 in the optical axis direction. The guide groove 7a moves the movable ring 4 in the optical axis direction. 7b is provided. Numeral 8 denotes a zoom motor, which is fixed to a motor base plate 9 screwed to a flange at the rear end of the fixed lens barrel 3, and an output gear 8 a provided on an output shaft thereof meshes with the zoom gear 7.

Reference numeral 10 denotes an end switch which is fixed to the fixed lens barrel 3 so as to be in contact with the zoom gear 7 on the outer peripheral portion of the fixed lens barrel 3 so as to be positioned on the movement line of the concave portion 7b for end detection, and to be turned on / off. The signal is taken out. Reference numeral 11 denotes a zoom stopper, which is screwed to an end face of the zoom gear 7 to regulate the zoom end. In addition, 12 is an eccentric roller,
In order to finely adjust the movable ring 4, the movable ring 4 is attached to the outer diameter surface of the movable ring 4 through a guide groove 7 a of the zoom gear 7 and a cutout 3 d of the fixed lens barrel 3. The lens barrel unit 20 is configured by the above components.

Next, the operation and adjustment procedure of the lens barrel unit 20 composed of the above components will be described. First, for various adjustments, the second group lens barrel 5 in the movable ring 4 is set to the notch 3d of the fixed lens barrel 3 and the guide hole 4a of the movable ring 4 to the screen size designated at the zoom end position with high sensitivity. Is adjusted in the optical axis direction with an eccentric roller or an eccentric tool to adjust the magnification to a predetermined screen size.
The group lens barrel 5 is fixed with screws 13. Next, the operation unit 6b is rotated along the cam lead 6a on the outer periphery of the third lens barrel 6 to perform focusing. After that, the first lens barrel 1 that is helicoidally coupled to the outer periphery of the fixed lens barrel 3 is rotated to adjust the image quality to a better state, and is fixed at the best position by the set screw 14. Finally, the optical performance in each zoom range is checked, and if there is no problem, the lens can be used as a lens. Then, it is attached to a product body such as a liquid crystal display device to be described later, a final check of the screen size is performed, and fine adjustment can be performed by the eccentric roller 12.

FIG. 3 shows a liquid crystal display device using the lens barrel unit 20. A light beam from a light source 22 in a display device body 21 passes through an illumination optical system 23 and is a dichroic mirror (R, G, B). A) a liquid crystal display element
To the liquid crystal display element 2 by the lens barrel unit 20.
5 is applied to the total reflection mirror 26.
And is projected on the screen 27 after being reflected.

In the lens barrel structure of this embodiment, the movable ring 4
Are arranged on the inner peripheral side of the fixed lens barrel 3.
It is needless to say that a configuration may be adopted in which the outer peripheral side is disposed. In the present embodiment, the guide groove 7a is formed integrally with the zoom gear 7, but the guide groove may be formed as a separate component.

[0014]

As described above, according to the first aspect of the present invention, the lens barrel structure has a first image quality adjustment function.
A second group consisting of a group, a moving lens barrel in the optical axis direction, and a lens barrel, a zoom lens optical system consisting of a third group consisting of a focus group for adjusting the second image quality, and each group By being constituted by a fixed lens barrel that is held and engaged and has a flange, a highly accurate screen size and the best image quality position can be obtained. According to the second aspect of the present invention, since the fixed lens barrel and the second lens unit have moving means for adjusting the magnification in the optical axis direction, the magnification can be easily and accurately adjusted. According to the third aspect of the present invention, the image quality can be easily and accurately adjusted by holding a part of the lenses of the first lens group in front of the fixed lens barrel.

According to a fourth aspect of the present invention, a guide groove for zooming and a member for transmitting driving are rotatable at a fixed position on the outer periphery of the fixed lens barrel, and end detection means is provided. The system can be properly controlled by the signal. According to a fifth aspect of the present invention, the fixed barrel has a moving cam lift for zoom, and the moving cam lift for zoom is a flat lift having a moving amount of 0 mm in the optical axis direction at both ends of the zoom in consideration of absorption of a manufacturing error. By having edge detection means,
An appropriate zoom operation can be performed. According to a sixth aspect of the present invention, there is provided a projection display device having the lens barrel according to any one of the first to fifth aspects, so that magnification adjustment and image quality adjustment can be performed even after the lens barrel is incorporated in the display device. Easy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a zoom lens barrel according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a configuration diagram of a liquid crystal projector using the zoom lens barrel.

[Explanation of symbols]

1 ·· 1 group lens barrel, 2 ·· front hood protection hood, 3 ··· fixed lens barrel, 4 ··· movable ring, 5 ··· 2 group lens barrel, 6 ··· 3rd group lens barrel, 7 ··· Zoom gear, 8 motor, 9 motor base plate, 10 end switch, 11 zoom stopper,
12. Eccentric roller, 20. Barrel unit, 21. Liquid crystal display device, 22. Light source unit, 23. Illumination optical system, 2
4. dichroic mirror, 25 liquid crystal display element,
26 total reflection mirror, 27 screen.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (for reference) G03B 21/00 G02B 7/04 D

Claims (6)

[Claims] A first group for adjusting a first image quality, a second group including a movable lens barrel and a lens barrel in the optical axis direction, and a second group.
A lens mirror comprising: a zoom lens optical system including a third group including a focus group for adjusting image quality; and a fixed lens barrel holding and engaging each group and having a flange. Tube. 2. The lens barrel according to claim 1, wherein said fixed lens barrel and said second lens group have moving means for adjusting magnification in the optical axis direction. 3. The lens barrel according to claim 1, wherein a part of lenses of the first lens group is held in front of the fixed lens barrel. 4. A zoom lens according to claim 1, wherein a guide groove for zooming and a transmission member for transmitting driving are rotatable at a fixed position on the outer periphery of said fixed lens barrel, and end detection means is provided. The lens barrel described. 5. The fixed barrel has a moving cam lift for zoom, and the moving cam lift for zoom has a flat lift at both ends of the zoom with a movement amount of 0 mm in the optical axis direction in consideration of absorption of a manufacturing error. 5. The lens barrel according to claim 1, further comprising a detecting unit. 6. A projection display device comprising the lens barrel according to claim 1. Description: