JP3754392B2 - Lens shift mechanism and projection-type image display device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a lens shift mechanism and a projection display apparatus.
[0002]
[Prior art]
FIG. 4 is a diagram illustrating an optical system of a three-plate color liquid crystal projector. The light emitting part 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 irradiated light is emitted as parallel light by a parabolic reflector and guided to the integrator lens 102.
[0003]
The integrator lens 102 is composed of a pair of lens groups, and each pair of lenses guides light emitted from the light source 101 to the entire surface of the liquid crystal light valves 111, 112, 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 that has passed through the first dichroic mirror 103 is reflected by the total reflection mirror 104 to change the optical path. The red light reflected by the total reflection mirror 104 is light-modulated by passing through the condenser lens 108 and the transmissive liquid crystal light valve 111 for red light. On the other hand, the 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 through the condenser lens 109 to the transmissive liquid crystal light valve 112 for green light, and is modulated by being transmitted therethrough. Further, the light in the blue wavelength band that has passed through the second dichroic mirror 105 is guided to the blue-light transmissive liquid crystal light valve 113 through the total reflection mirrors 106 and 107 and the condenser lens 110 and is transmitted therethrough. Is modulated by light.
[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 (pixel electrodes and alignment films are formed), an outgoing-side polarizing plate, Comprising. The modulated light (each color video light) modulated by passing through the liquid crystal light valves 111, 112, 113 is synthesized by the dichroic prism 114 to become color video light. The color image light is enlarged and projected by the projection lens unit 115 and projected and displayed on the screen.
[0007]
FIG. 5 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, it is possible to move the projected image up and down without changing the liquid crystal projector main body, and to reduce the projection image from becoming trapezoidal.
[0008]
Sliding bearings 121 a are provided at the four corners of the moving base 121 to which the projection lens unit 115 is fixed. Is done. A plate member 121 b is fixed to the side portion of the moving base 121. A screw hole is formed in the plate member 121b, and the male screw portion 123a of the elevating shaft 123 is screwed into the screw hole. The screw shaft 123 is only allowed to rotate, and the upper and lower portions are supported by bearings 124 so as not to move up and down. 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 portion of the screw shaft 123, and a worm screw 126 fixed to the rotating shaft of the motor 127 is screwed to the worm gear 125. As the rotation shaft of the motor 127 rotates, the screw shaft 123 rotates and the plate member 121b moves 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, in order to smoothly move the moving base 121 up and down, the guide shaft 122 is made of a metal such as stainless steel and is smoothly ground, and the bearing 121a is polyacetal (POM) or the like. Resin and oilless bearings are used. However, in order to reduce the shaft runout when the moving base 121 moves up and down, it is necessary to reduce the gap between the guide shaft 122 and the bearing 121a, and the dimension from the reference surface of the moving base 121 to the four bearings 121a. High accuracy is required for the parallelism, and the dimension and parallelism from the reference surface of the fixed base 129 to the guide shaft 122. If these tolerances are reduced, they move due to component variations and cumulative errors. The base 121 may not be lifted and lowered smoothly.
[0010]
If the conventional lens shift mechanism is used to move the projection lens unit 115 up and down and left and right, the components such as the moving base 121, the guide shaft 122, the sliding bearing 121a, and the screw shaft 123 are moved up and down. Two sets for shifting are required, which causes problems such as an increase in the number of parts, an increase in weight, and a decrease in assembly workability.
[0011]
In view of the above circumstances, the present invention is provided with 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 can be easily operated, and the lens shift mechanism. Another object of the present invention is to provide a projection display apparatus.
[0012]
[Means for Solving the Problems]
The lens shift mechanism of the present invention is a lens shift mechanism that shifts a projection lens unit that performs image projection in a direction orthogonal to the optical axis thereof, and a lens mounting member to which the projection lens unit is fixed; and the lens mounting member A contact surface portion that comes into contact with, a pressing means that presses the lens mounting member toward the contact surface portion, a rotating member that is provided with a lever on one side and an operating piece on the other side, and an operating piece Is engaged with the lens mounting member, and a lever is connected to a lever driving screw mechanism, and the lever is rotated by the lever driving screw mechanism to move the position of the projection lens unit. It is characterized by that.
[0013]
In the above configuration, since the guide shaft, the sliding bearing, the screw shaft, etc. in the lens shift mechanism of the conventional configuration are unnecessary, the structure is hardly complicated even when the projection lens unit is shifted up and down and left and right. Further, since the projection lens unit can be shifted by the lever driving screw mechanism, the shifting operation is easy.
[0014]
Further, in the above configuration, the lever driving screw mechanism may be configured to be operated by a user. The lever driving screw mechanism may be configured to be driven by an actuator.
[0015]
According to another aspect of the present invention, there is provided a projection type image display apparatus in which the light emitted from the light source is modulated by a light valve and projected by a projection lens unit. It is characterized by having.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A lens shift mechanism and a projection display apparatus according to the present invention will be described below with reference to FIGS. Note that the projection display apparatus according to the embodiment shown below is a liquid crystal projector using three transmissive liquid crystal display panels, and the liquid crystal projector shown in FIG. Therefore, the description of the optical system is omitted, and the lens shift mechanism will be mainly described.
[0017]
(Embodiment 1)
FIG. 1 is a view showing a lens shift mechanism of a type that directly moves the projection lens unit 115, where FIG. 1 (a) is a cross-sectional view and FIG. 1 (b) is a front view. The projection lens unit 115 is mounted on the mounting surface of the lens mounting plate 2, and a plurality (for example, four) of sliding contact bosses 2 a are formed on the surface opposite to the mounting surface. The sliding contact boss 2a is not limited to integral molding, and may be a separate body. In this case, the sliding contact boss 2a is made of polyacetal (POM), polyamide (PA), It is desirable to form using tetrafluoroethylene (PTFE) or the like. The rear lens 115 a is fixed by the lens mounting plate 2, but is not limited thereto, and may be fixed by the projection lens unit 115.
[0018]
A flat box-shaped sliding base 3 is fixed to the housing 1 of the projection display apparatus. The sliding base 3 accommodates the lens mounting plate 2 and the rear end portion of the projection lens unit 115, and the sliding contact boss 2 a of the lens mounting plate 2 is in contact with the inner bottom surface of the sliding base 3. . A cover member 4 is attached to the open end side of the sliding base 3 with screws 5.
[0019]
A plurality (for example, four) of spring supporting bosses 4 a are formed on the back surface side of the cover member 4. A coil spring 6 is fitted on each spring supporting boss 4a. At the tip of the spring supporting boss 4a, there is provided a seat portion 8 for receiving and biasing the coil spring 6 to support and bias the sliding contact body 7. The shaft portion of the seat portion 8 is movably fitted in a support hole formed on the tip side of the boss 4a. When the cover member 4 is attached to the sliding base 3 with the screw 5, the coil spring 6 is in a contracted state, and the sliding contact body 7 is pressed against the lens mounting plate 2, whereby the lens mounting plate 2 is brought into contact with the sliding base 3. Pressed. That is, the lens mounting plate 2 is sandwiched between the sliding base 3 and the sliding contact body 7 and is elastically supported and pressed against the sliding base 3. The pressing force at this time is set so that the lens mounting plate 2 (projection lens unit 115) can be held and moved. That is, if the user applies a moving force to the projection lens unit 115, the projection lens unit 115 moves. If the user stops applying the force, the pressing force is applied so that the position of the projection lens unit 115 is maintained at that position. Is set.
[0020]
A cylindrical protruding portion 4 b having a cylindrical shape is formed at the center of the front surface side of the cover member 4 so as to surround the projection lens unit 115. A gap corresponding to the shift width of the projection lens unit 115 is secured between the inner surface of the cylindrical protrusion 4 b and the projection lens unit 115.
[0021]
In the above lens shift mechanism, the projection lens unit 115 can be shifted to desired positions in the vertical and horizontal directions by placing a finger on the cylindrical protrusion 4b and the projection lens unit 115. Further, since the projection lens unit 115 can be moved by placing a finger on the cylindrical protrusion 4b in this way, the projection display apparatus itself does not move.
[0022]
(Embodiment 2)
FIG. 2 is a cross-sectional view showing a lever driving type lens shift mechanism using a screw mechanism. The screw mechanism 16 is rotatably provided on the cylindrical protrusion 4b 'and is configured not to move in the axial direction thereof. The screw mechanism 16 includes a knob portion 16a positioned outside the cylindrical protrusion 4b 'and a shaft portion 16b which is locked to the cylindrical protrusion 4b' and has a screw portion at the tip. The tip screw portion of the shaft portion 16b is located in the cylindrical protrusion 4b 'and is screwed into a screw hole formed in the lever 11C. The rotating shaft 12C has a length corresponding to the height of the cylindrical protruding portion 4b ', and one end and the other end of the rotating shaft 12C are fitted and supported in holes formed in the cylindrical protruding portion 4b'. Move. The rotating shaft 12C is formed with an operating piece 13C protruding perpendicular to the axial direction. The operating piece 13C is engaged with a recess formed in the lens mounting plate 2C. By turning the knob portion 16a of the screw mechanism 16, the lever 11C is driven, and the position of the lens mounting plate 2C (projection lens unit 115) is moved. Further, since the lever 11C is screwed to the screw mechanism 16, the lever 11C naturally has a function of fixing the lever 11C at an arbitrary position.
[0023]
In the above example, the screw mechanism 16 is configured to be operated by a user. However, the screw mechanism 16 may be configured to be driven by an actuator such as a motor.
[0024]
(Embodiment 3)
3A and 3B are diagrams showing a lens shift mechanism of a type that directly moves the projection lens unit 115. FIG. 3A is a cross-sectional view, and FIG. 3B is a front view. The structure is the same as the lens shift mechanism shown in FIG. 1, but the cylindrical protrusion 41 is not fixed to the cover member 4 but is screwed to the cover member 4. By screwing the cylindrical protruding portion 41, the lens mounting plate 2 is pressed against the sliding base 3 by the cylindrical protruding portion 41, and the lens mounting plate 2 becomes immovable. That is, in the type in which the projection lens unit 115 is directly moved, the cylindrical protrusion 41 is provided with a stopper mechanism. Here, the inner end of the cylindrical projecting portion 41 may be directly pressed against the lens mounting plate 2, but in the structure of FIG. 3, between the inner end of the cylindrical projecting portion 41 and the lens mounting plate 2. A plate member 17 is interposed therebetween.
[0025]
In the embodiment described above, the coil spring 8 is shown as means for urging the lens mounting plate 2 toward the sliding base 3, but other springs such as a leaf spring are used instead of the coil spring 8. You may use, or you may use elastic bodies, such as not only a spring but rubber. Further, the cover member 4 is provided with the spring supporting boss 4a, the coil spring 6, the sliding contact body 7 and the like. However, these are provided on the lens mounting plate 2 side, and the back surface of the cover member 4 is the sliding contact surface. Is also good. In addition, the image generation optical system using three transmissive liquid crystal display panels is shown. However, the image generation optical system is not limited to such an image generation optical system, and may be applied to the case of using another image generation optical system. it can.
[0026]
【The invention's effect】
As described above, according to the present invention, since the guide shaft, the sliding bearing, the screw shaft, etc. in the lens shift mechanism of the conventional configuration are unnecessary, the structure of the structure can be achieved even when the projection lens unit is shifted up and down and left and right. Complexity is unlikely to occur. In addition, since the projection lens unit can be shifted by the lever driving screw mechanism, the shift operation can be easily performed.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a lens shift mechanism of a projection lens unit direct shift type according to the present invention, in which FIG. 1A is a cross-sectional view and FIG. 1B is a front view.
FIG. 2 is a longitudinal sectional view showing a screw mechanism lever operation type lens shift mechanism of the present invention;
FIGS. 3A and 3B are diagrams showing a lens shift mechanism with a stopper function of the projection lens unit direct shift type of the present invention, in which FIG. 3A is a cross-sectional view, and FIG. 3B is a front view. is there.
FIG. 4 is an explanatory diagram showing an optical system of a general liquid crystal projector.
FIG. 5 is a perspective view showing a conventional lens shift mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 Lens mounting plate 3 Sliding base 4 Cover member 4a Spring support boss | hub 4b, 4b 'Cylindrical protrusion part 6 Coil spring 7 Sliding contact body 8 Seat part 11C Lever 12C Rotating shaft 13C Actuation piece 16 Screw mechanism 115 Projection lens unit

Claims (4)

In a lens shift mechanism that shifts a projection lens unit that performs image projection in a direction orthogonal to the optical axis thereof, a lens mounting member to which the projection lens unit is fixed, a contact surface portion in contact with the lens mounting member, A pressing means for pressing the lens mounting member toward the contact surface, a rotating member having a lever on one side and an operating piece on the other side, and engaging the operating piece with the lens mounting member A lens shift mechanism, wherein the lever is coupled to a lever driving screw mechanism, and the lever is rotated by the lever driving screw mechanism to move the position of the projection lens unit. .   2. The lens shift mechanism according to claim 1, wherein the lever driving screw mechanism is configured to be operated by a user.   The lens shift mechanism according to claim 1, wherein the lever driving screw mechanism is configured to be driven by an actuator.   4. A projection type image display apparatus that modulates light emitted from a light source with a light valve and projects an image with a projection lens unit, comprising the lens shift mechanism according to any one of claims 1 to 3. A projection-type image display device characterized by that.