JP2004085910A - Lens shift mechanism and projection type video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens shift mechanism in which no additional complexity is generated for the structure even though a projection lens unit is shifted along up and down and left and right directions and shift operations are easily conducted. <P>SOLUTION: In the lens shift mechanism, the lens unit mounted on a lens holder 3 is shifted along the direction orthogonal to the optical axis of the unit. The holder 3 is pressed to a second fixed side plate member 2 by a pressing means disposed on the back surface of a first fixed side plate member 1 and the pressing force is set to hold and/or move the position of the holder 3 (a lens unit). A plurality of dials 43 and 43 are arranged to move the unit in the up and down and the left and right shift directions. Having received the operating force of the dials 43 and 43, a plurality of driving mechanisms 4A and 4B move the holder 3 along the direction specified by the dial operations. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a lens shift mechanism and a projection type video display.
[0002]
[Prior art]
FIG. 8 is a diagram illustrating an optical system of a three-panel color liquid crystal projector. The light-emitting portion of the light source 101 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like, and the irradiation light is emitted as parallel light by a parabolic reflector and guided to an integrator lens 102.
[0003]
The integrator lens 102 is composed of a pair of lens groups, and each lens pair guides light emitted from the light source 101 to the entire surface of the liquid crystal light valves 111, 112, and 113. The light that has passed through the integrator lens 102 is guided to the first dichroic mirror 103.
[0004]
The first dichroic mirror 103 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band transmitted through the first dichroic mirror 103 is reflected by the total reflection mirror 104 and the optical path is changed. The red light reflected by the total reflection mirror 104 passes through a condenser lens 108 and passes through a transmissive liquid crystal light valve 111 for red light to be light-modulated. On the other hand, light in the cyan wavelength band reflected by the first dichroic mirror 103 is guided to the second dichroic mirror 105.
[0005]
The second dichroic mirror 105 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 105 is guided to the transmission type liquid crystal light valve 112 for green light via the condenser lens 109, and is transmitted therethrough to be modulated. Further, the light in the blue wavelength band transmitted through the second dichroic mirror 105 is guided to the transmission type liquid crystal light valve 113 for blue light through the total reflection mirrors 106 and 107 and the condenser lens 110, and transmitted therethrough. The light is modulated.
[0006]
Each of the liquid crystal light valves 111, 112, and 113 includes an incident-side polarizing plate, a panel portion in which liquid crystal is sealed between a pair of glass substrates (on which a pixel electrode and an alignment film are formed), and an output-side polarizing plate. It comprises. The modulated light (image light of each color) modulated by passing through the liquid crystal light valves 111, 112, and 113 is combined by the dichroic prism 114 to become color image light. The color image light is enlarged and projected by the projection lens unit 115, and is projected and displayed on a screen.
[0007]
FIG. 9 is a perspective view showing a lens shift mechanism for moving the projection lens unit 115 in the vertical direction. With this lens shift mechanism, the projected image can be moved up and down without changing the liquid crystal projector main body, and the trapezoidal shape of the projected image can be reduced.
[0008]
Sliding bearings 121a are provided at four corners of the moving base 121 to which the projection lens unit 115 is fixed, and a guide shaft 122 is inserted through these sliding bearings 121a. The moving base 121 is guided vertically along the guide shaft 122. Is done. A plate member 121b is fixed to a side portion of the movable base 121. A screw hole is formed in the plate member 121b, and a male screw portion 123a of the elevating shaft 123 is screwed into the screw hole. The screw shaft 123 is allowed to rotate only, and its upper and lower parts are supported by bearings 124 so that vertical movement does not occur. The bearing 124 and the guide shaft 122 are fixed to a fixed base 129. A worm gear 125 is fixed to the lower end of the screw shaft 123, and a worm screw 126 fixed to the rotation shaft of the motor 127 is screwed to the worm gear 125. When the rotation shaft of the motor 127 rotates, the screw shaft 123 rotates to move the plate member 121b up and down, and the moving base 121 connected to the plate member 121b moves up and down.
[0009]
[Problems to be solved by the invention]
In the lens shift mechanism, the guide shaft 122 is made of a metal such as stainless steel and smoothly ground, and the bearing 121a is made of polyacetal (POM) or the like in order to smoothly move the moving base 121 up and down. Resin and oilless bearings. However, it is necessary to reduce the gap between the guide shaft 122 and the bearing 121a in order to reduce the shaft runout when the moving base 121 is moved up and down. And the degree of parallelism and the dimension and parallelism from the reference surface of the fixed base 129 to the guide shaft 122 are required to be high. If these tolerances are reduced, the parts may move due to variation and accumulated error. The elevation of the base 121 may not be performed smoothly.
[0010]
If the vertical and horizontal movement of the projection lens unit 115 is to be realized by the above-described conventional lens shift mechanism, the components such as the moving base 121, the guide shaft 122, the slide bearing 121a, the screw shaft 123, etc. Two sets for shifting are required, which causes problems such as an increase in the number of parts, an increase in weight, and a reduction in assembly workability.
[0011]
In view of the above circumstances, the present invention includes a lens shift mechanism and a lens shift mechanism that does not easily complicate the structure even when the projection lens unit is shifted up, down, left, and right, and that is easy to shift. To provide a projection type video display device.
[0012]
[Means for Solving the Problems]
According to another aspect of the present invention, there is provided a lens shift mechanism for shifting a projection lens unit for projecting an image in a direction orthogonal to an optical axis of the projection lens unit, wherein the projection lens unit is fixed. The mounting member, the contact surface portion with which the lens mounting member is in contact, and the lens mounting member are pressed toward the contact surface portion, and the pressing force enables the position holding and the position movement of the projection lens unit. A set pressing means, a dial operated in a direction corresponding to the shift direction, and a drive mechanism for receiving the operation force of the dial and moving the lens mounting member in the dial operation direction. And
[0013]
In the above configuration, since the guide shaft, the slide bearing, and the like in the conventional lens shift mechanism are not required, the structure is not likely to be complicated even when the projection lens unit is shifted up, down, left, and right. Moreover, a dial operated in the direction corresponding to the shift direction and a driving mechanism for moving the lens mounting member in the dial operation direction by receiving the operation force of the dial are provided, so that the projection lens unit is shifted rightward. If you want to shift the projection lens unit upward, you just need to apply an upward operation force to the dial. The lens shift operation can be performed without a feeling of strangeness.
[0014]
The drive mechanism includes a rotation member having a rotation center parallel to the optical axis, and the rotation member is provided with a protrusion at an eccentric position from the rotation center. The part may be engaged with the lens mounting member. Further, a screw portion may be provided on the dial, a moving member may be screwed into the screw portion, and the rotating member may be configured to rotate by moving the moving member.
[0015]
It is preferable to provide two of the driving mechanisms so that the projection lens unit moves vertically and horizontally. A first guide body for guiding the projection lens unit in the up-down direction and a second guide body for guiding the projection lens unit in the left-right direction, and a guide projection in each guide body is a guide hole formed in the lens mounting member. The first guide has an axis in the up-down direction and is provided to be swingable in the left-right direction, and the second guide body has an axis in the left-right direction, and is swingable in the up-down direction. It is good to adopt the structure provided in the.
[0016]
According to a projection type video display device of the present invention, in the projection type video display device in which light emitted from a light source is light-modulated by a light valve and an image is projected by a projection lens unit, any one of the above-described lens shift mechanisms is provided. It is characterized by having.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a lens shift mechanism and a projection type video display device of the present invention will be described with reference to FIGS. The projection type image display device of the embodiment described below is a liquid crystal projector using three transmission type liquid crystal display panels, and the image generation optical system is the same as the liquid crystal projector shown in FIG. Therefore, the description of the optical system will be omitted, and the lens shift mechanism will be mainly described.
[0018]
FIG. 1 is a perspective view showing a lens shift mechanism of this embodiment. The lens shift mechanism includes a first fixed side plate 1, a second fixed side plate 2, a lens holder 3, drive mechanisms 4A and 4B, and guide members 5A and 5B. The second fixed side plate 2 is fixed to a chassis of the liquid crystal projector. A lens unit (not shown) is fixed to the lens holder 3.
[0019]
2A and 2B show the first fixed side plate 1, wherein FIG. 2A is a plan view and FIG. 2B is a side view. The central circular through hole portion is a through hole 1a for a lens unit (not shown), and the right rectangular through hole 1b and the lower rectangular through hole 1c communicating with the through hole 1a are used for the guide members 5A and 5B. Mounting holes. In the standing portion 1d, two round holes 1e are formed in a direction perpendicular to the paper surface of FIG. 3A (parallel to the optical axis direction of the lens unit), and a round hole is formed in each of the round holes 1e. The moving member 41 is rotatably inserted. Further, holes 1f are formed on the lower surface of the first fixed side plate member 1, and the sliding contact body 11 is inserted into each hole 1f. The sliding body 11 is formed using, for example, polyacetal (POM), polyamide (PA), polytetrafluoroethylene (PTFE), or the like. A coil spring 12 is provided in each hole 1f, and the sliding member 11 presses the lens holder 3 toward the second fixed side plate 2 by the coil spring 12. The pressing force at this time is set so that the position of the lens holder 3 (lens unit) can be held and moved. That is, if a force for movement is applied to the lens holder 3, the lens holder 3 moves, and if the force is stopped, the pressing force is set so that the position of the lens holder 3 is held at that position.
[0020]
3A and 3B are views showing the second fixed side plate member 2, wherein FIG. 3A is a plan view thereof, and FIG. 3B is a side view thereof. Standing portions 2a are formed at two edge sides of the second fixed side plate member 2. The first fixed side plate 1 is placed on the upright portion 2a and is screwed to fix the first fixed side plate 1 and the second fixed side plate 2 and a space therebetween. Is formed so that the lens holder 3 can be located in this space. Further, the second fixed side plate 2 is formed with sliding contact protrusions 2b, and the lens holder 3 is mounted on the sliding contact protrusions 2b.
[0021]
4A and 4B are views showing the lens holder 3, wherein FIG. 4A is a plan view thereof, and FIG. 4B is a side view thereof. The central through hole 3a is a light introducing hole for a lens unit (not shown). 5A, a concave groove 3b long in the left-right direction is a hole in which a projection 41a (see FIGS. 5 and 6) of a rotating member 41 for moving the lens holder 3 in the vertical direction in the figure is engaged. The concave groove 3c which is long in the vertical direction in the figure is a hole in which the projection 41a of the rotating member 41 for moving the lens holder 3 in the horizontal direction in the figure is engaged. In addition, it is preferable to provide a member for reducing friction in the concave grooves 3b and 3c. The cut portions 3d, 3d and the cut portions 3e, 3e are provided with L-shaped fittings (not shown) to form concave grooves, and the guide protrusions 51 of the guide members 5A, 5B are engaged with the cut grooves. ing.
[0022]
FIG. 5 is a perspective view showing an engagement state between the protrusion 41a of the rotating member 41 and the concave groove 3c in the drive mechanism 4A, and FIG. 6 is a side view of the rotating member 41. A projecting portion 41b projecting laterally is formed at a lower portion of the rotating member 41, and the projecting portion 41a is formed on the lower surface of the distal end of the projecting portion 41b. That is, the projection 41 a is eccentric with respect to the center of rotation of the rotating member 41. In addition, a projecting portion 41c that projects laterally is formed on an upper portion of the rotating member 41. The projecting direction of the projecting portion 41c is shifted from the projecting direction of the projecting portion 41b by 90 °. A projection 41d is formed on the top surface of the tip of the projection 41c. That is, the protrusion 41d is also eccentric with respect to the rotation center of the rotation member 41. The protrusion 41d is engaged with a hole formed on the lower surface of the moving member 42.
[0023]
The moving member 42 is screwed into a screw portion 44 fixed to the dial 43. The dial 43 and the screw portion 44 are provided such that only rotation is allowed and movement in the axial direction is restricted. In FIG. 5, when the dial 43 is operated in the direction A, the moving member 42 moves in the direction B. When the moving member 42 moves in the B direction, the turning member 41 turns in the C direction. The projection 41a pushes the lens holder 3 in the direction D by the rotation of the rotation member 41 in the direction C. That is, when the dial 43 is turned in the direction A, the lens holder 3 (lens unit) moves in the direction D which is the same direction as the direction A. The drive mechanism 4B has the same mechanism as the drive mechanism 4A, as shown in FIG. 7A, but the arrangement is shifted by 90 ° with respect to the drive mechanism 4A. I have.
[0024]
As shown in FIG. 7 (b), the guide member 5A has guide protrusions 51 at the lower portions at both ends in the longitudinal direction. The guide member 5 </ b> A has a shaft 52 on the upper side of both ends in the longitudinal direction, and the axial direction coincides with the shift direction (up-down direction) of the lens holder 3. Further, the guide member 5B has guide protrusions 51 at lower portions at both ends in the longitudinal direction, and a shaft 52 at upper ends on both ends in the longitudinal direction, and the axial direction matches the shift direction (left-right direction) of the lens holder 3. Let me.
[0025]
The guide member 5A secures the movement linearity when the lens holder 3 moves by operating the dial 43 of the drive mechanism 4A, and when the lens holder 3 moves by operating the dial 43 of the drive mechanism 4B. Then, by swinging about the shaft 52, the lens holder 3 follows the lens holder 3 and maintains the engagement state with the lens holder 3. In addition, the guide member 5B secures linear movement when the lens holder 3 moves by operating the dial 43 of the drive mechanism 4B, and moves the lens holder 3 by operating the dial 43 of the drive mechanism 4A. At this time, by swinging about the shaft 52, the lens holder 3 follows the lens holder 3 and maintains the engagement state with the lens holder 3.
[0026]
In the above-described embodiment, the coil spring 12 is used as a means for pressing the lens holder 3 against the second fixed side plate member 2. However, another spring such as a plate spring may be used instead of the coil spring 12. Alternatively, the present invention is not limited to a spring, and an elastic body such as rubber may be used. Further, the present invention is not limited to pressing the lens holder 3 against the second fixed side plate 2, and it is also possible to press the lens holder 3 against the first fixed side plate 1. In addition, a gear may be fixed to the upper end of the rotating member 41 instead of the moving member 42, and a worm gear mechanism configuration may be employed. Further, the image generation optical system using three transmission type liquid crystal display panels has been described. However, the present invention is not limited to such an image generation optical system, and may be applied to a case where another image generation optical system is used. it can.
[0027]
【The invention's effect】
As described above, according to the present invention, since the guide shaft and the slide bearing in the conventional lens shift mechanism are not required, the structure becomes complicated even when the projection lens unit is shifted up, down, left and right. It is unlikely to occur. Moreover, if you want to shift the projection lens unit to the right, you only need to apply a right operating force to the dial.If you want to shift the projection lens unit upward, you need to apply an upward operating force to the dial. This is an effect that the user can perform the lens shift operation without feeling uncomfortable.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a lens shift mechanism of the present invention.
FIGS. 2A and 2B are views showing a first fixed side plate member, wherein FIG. 2A is a plan view thereof and FIG. 2B is a side view thereof.
3A and 3B are diagrams showing a second fixed side plate member, wherein FIG. 3A is a plan view and FIG. 3B is a side view.
4A and 4B are views showing a lens holder, wherein FIG. 4A is a plan view thereof, and FIG. 4B is a side view thereof.
FIG. 5 is a perspective view showing an engagement state between a protrusion of a rotation member and a concave groove in the drive mechanism.
FIG. 6 is a side view of the rotating member.
FIG. 7A is a plan view of a lens shift mechanism, and FIG. 7B is a side view thereof.
FIG. 8 is an explanatory diagram showing an optical system of a general liquid crystal projector.
FIG. 9 is a perspective view showing a conventional lens shift mechanism.
[Explanation of symbols]
Reference Signs List 1 First fixed side plate 2 Second fixed side plate 3 Lens holder 4A Drive mechanism 4B Drive mechanism 5A Guide member 5B Guide member 41 Rotating member 42 Moving member 43 Dial 44 Screw part 115 Projection lens unit

Claims (6)

In a lens shift mechanism that shifts a projection lens unit that performs image projection in a direction orthogonal to the optical axis, a lens mounting member to which the projection lens unit is fixed, a contact surface portion with which the lens mounting member contacts, Pressing means for pressing the lens mounting member toward the contact surface portion, the pressing force being set to enable the position holding and the position movement of the projection lens unit, and operation in a direction corresponding to the shift direction And a driving mechanism for receiving the operating force of the dial and moving the lens mounting member in the dial operating direction. 2. The lens shift mechanism according to claim 1, wherein the driving mechanism has a rotation member having a rotation center parallel to the optical axis, and the rotation member has a position eccentric from the rotation center. A lens shift mechanism, wherein a projection is provided on the lens mounting member. 3. The lens shift mechanism according to claim 2, wherein a screw portion is provided on the dial, a moving member is screwed to the screw portion, and the rotating member is rotated by the movement of the moving member. A lens shift mechanism comprising: 4. The lens shift mechanism according to claim 1, further comprising two drive mechanisms for moving the projection lens unit up and down and right and left. 5. The lens shift mechanism according to claim 4, further comprising a first guide body for guiding the projection lens unit in a vertical direction and a second guide body for guiding the projection lens unit in a left-right direction. The first guide is engaged with a guide hole formed in the lens mounting member, the first guide has a vertical axis, and is provided to be swingable in the horizontal direction, and the second guide body has a horizontal axis. A lens shift mechanism, which is provided so as to be swingable in a vertical direction. A projection-type image display device for modulating light emitted from a light source with a light valve and projecting an image with a projection lens unit, comprising the lens shift mechanism according to any one of claims 1 to 5. Characteristic projection type video display device.

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