JP2012155055A - Projection type image display device with focal position correction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a focal position shift for a focal position correction when the device is used with a fixed focal position, without requiring a user to change setup conditions.SOLUTION: The device automatically judges whether the device is used with a fixed focal position. If the device detects that the device is used with a fixed focal position, the device avoids a focal position shift for a focal position correction and pulse-signal detection error reset.

Description

  The present invention relates to a focus position correction algorithm for a projection type image display apparatus having a focus position correction mechanism.

  In a projection type image display apparatus such as a projector, light from a light source is converted into an image by an optical element such as a polarization conversion element, and the image is enlarged and projected by a lens unit to be focused on a projection surface such as a screen. While the light source is on, the optical element and the optical element holding member of the projection type image display apparatus such as the projector are always in a state of receiving light from the light source. Due to the influence of light, the optical element and the optical element holding member rise in temperature immediately after the start of projection. As the temperature rises, optical characteristics such as refractive index of the optical element change, and the optical element holding member expands and contracts due to linear expansion, and the distance between the optical elements changes. Due to the change in the optical characteristics and the change in the optical element spacing, the focal position of the projection surface such as the screen moves immediately after the start of projection. If the movement of the focal position is within the depth of the projected image, there is no problem, but if the depth is exceeded, the projected image deteriorates.

  In order to solve this problem, a technique for avoiding deterioration of a projected image by adjusting the focal position in accordance with the movement of the focal position is known. For example, in Patent Document 1, a temperature sensor is arranged in a projection-type image display device, and a focus position is adjusted based on a predetermined focus position adjustment algorithm and a detection result of the temperature sensor to avoid deterioration of a projected image. Is disclosed.

  In addition, when the power is turned off and then turned on again after adjusting the focal position, the temperature of the optical element and the optical element holding member may be different from the temperature when the power is turned off due to a change in environmental temperature or heat dissipation. Yes, if the focal position is left as it is when the power is turned off, the image deteriorates, which causes a problem. In addition, when the focus position is moved to the position where the focus position adjustment was started at the time of previous lighting at the time of re-lighting, the optical element and the optical element holding member start to adjust the focus position due to a change in environmental temperature or heat dissipation. The temperature may be different from that of the image, and the image is deteriorated. To solve this problem, the focus position correction amount is calculated from the difference between the detection result when the focus position correction is started when the temperature sensor is previously turned on and the detection result when the temperature sensor is turned on again, and the focus position is adjusted when the temperature sensor is turned on last time. There is a technique for avoiding the deterioration of the image by moving the focus position from the start position to a position to which the focus position correction amount is added.

  Further, when adjusting the focal position, an error is added to the movement of the focal position due to the measurement error of the temperature sensor and the backlash of the motor that moves the focal position. If the error is accumulated every time the focus position is adjusted, image deterioration occurs every time the light is turned on again, which becomes a problem. To solve this problem, there is a technique for detecting the absolute position of the focal position, and avoiding the accumulation of the error by adjusting the adjustment amount of the focal position to the absolute position instead of the movement amount.

JP 2000-19648 A

  When a projection type image display apparatus such as a projector is fixedly installed by using a ceiling or the like, the focal position is also fixed. For this reason, in the lens unit described in the background art, the focal position moves due to the correction of the focal position, which causes a problem when the focal position is fixed. In order to detect the absolute value of the focal position, a switch for detecting the reference point from the point of resolution, cost and space and a pulse plate on the output shaft of the motor for detecting the amount of movement from the reference point. An attachment pulse signal may be used. In this configuration, if the reference point is frequently detected and the detection error of the pulse signal is not reset, the error accumulates. Therefore, it is necessary to reset the detection error of the pulse signal by moving the focus position to the switch each time the lamp is turned on. . However, when the focus position is fixed and used, there is still a problem because the focus position moves each time the lamp is turned on.

  In order to achieve the above object, the present invention has a means for automatically determining that the focus position is fixed and used, and when determining that the focus position is fixed and used. Further, the focal position is not moved to correct the focal position correction and the detection error of the pulse signal.

  According to the present invention, even when a projection type image display apparatus such as a projector has a focal position correction, the focal position is fixed when the focal position is used without causing the user to switch the installation state. Thus, it is possible to provide a projection type image display apparatus such as a projector that does not move the focal position by the correction.

1 is an external view of a liquid crystal projector that is Embodiments 1 and 2 of the present invention. FIG. FIG. 3 is an exploded perspective view of the lens unit according to the first embodiment. FIG. 3 is an exploded perspective view of the motor unit according to the first embodiment. 2 is a flowchart of the first embodiment. 9 is a flowchart according to the second embodiment. 9 is a flowchart according to the third embodiment. 10 is a flowchart of Example 4. 10 is a flowchart of Example 5. 10 is a flowchart of Example 6. 10 is a flowchart of Example 7. 10 is a flowchart of Example 8. 10 is a flowchart of Embodiment 9. 10 is a flowchart of Example 10. 12 is a flowchart of Example 11. 20 is a flowchart of Example 12.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Example 1]
FIG. 1 shows an external appearance of a projector 300 including a lens unit 100 that is Embodiment 1 of the present invention.

  An image supply device such as a personal computer, a DVD player, or a TV tuner is connected to the liquid crystal driving circuit of the projector 300. Based on image (video) information input from the image supply device, the projection lens 100 enlarges and projects an image in focus on a projection surface such as a screen.

  The projector 300 has a mechanism for adjusting the focal position movement due to the temperature change of the optical element and the optical element holding member.

  FIG. 2 is an exploded perspective view of the lens unit 100 of the present embodiment.

  Reference numeral 101 denotes a first lens barrel that holds the first lens group. Reference numeral 102 denotes a second group barrel that holds the second lens group. Reference numeral 103 denotes a third lens barrel that holds the third lens group. Reference numeral 104 denotes a fourth lens barrel that holds the fourth lens group, and reference numeral 105 denotes a fifth lens barrel that holds the fifth lens group. Reference numeral 106 denotes a sixth lens barrel that holds the sixth lens group.

  Reference numeral 107 denotes a fixed cylinder as a lens barrel body. A mount portion (flange portion) 107B that is screwed to the optical box described above is formed at the position of the rear end portion in the optical axis direction of the fixed tube 107 (end portion on the sixth lens barrel side).

  Reference numeral 108 denotes a cam ring as a first rotating ring which is arranged in a region on the front side (first lens barrel side) of the inner periphery of the fixed cylinder 107 and rotates around the optical axis. Reference numeral 110 denotes a focus ring as a second rotary ring that is arranged in the region on the front side (first lens barrel side) of the outer periphery of the fixed cylinder 107 and rotates around the optical axis. Reference numeral 109 denotes a cam follower attached to the first to fifth lens barrels 101 to 105 with screws. The first lens barrel 101 to which the cam follower 109 is attached is fixed to the end portion (first lens barrel side) of the fixed tube 107 via the cam follower 109. The second lens barrel 102 to which the cam follower 109 is attached engages with a cam groove formed in the focus ring 110. The third to fifth lens barrels 103 to 105 to which the cam follower 109 is attached engage with cam grooves formed in the cam ring 108, respectively. A zoom ring 111 has a gear portion and is attached to the first lens barrel side of the cam ring 108.

  Reference numeral 112 denotes a motor unit as an actuator. The motor unit includes a motor body such as a stepping motor, a DC motor, and a vibration motor, a reduction gear box that decelerates and outputs the rotation of the motor body, a pulse plate for expressing the motor drive as a rotation angle, And a substrate holding a photo interrupter for outputting a rotation angle detection result as a pulse signal. The motor unit 112 is a focus drive source and a zoom drive source. Reference numeral 114 denotes a switch for detecting a reference of a focal position when the focus ring 110 rotates around the optical axis. A holding member 113 holds the motor 112 and the switch 114. The motor 112 and the switch 114 are fixed to the holding member 113 with screws. The holding member 113 is fixed to the fixed cylinder 107 with screws.

  The second lens barrel 102 is a focus lens. Here, the focus drive mechanism will be described. Cam followers 109 are attached to three locations on the outer periphery of the second lens barrel 102 every 120 ° in the circumferential direction. The cam follower 109 provided in the second lens barrel 102 engages with a rectilinear groove 107A formed in the fixed cylinder 107 so as to extend in the optical axis direction. Further, it engages with a cam groove formed in the focus ring 110.

  Further, the focus ring 110 is rotatable around the optical axis in a state where movement in the optical axis direction is prevented with respect to the fixed cylinder 107 by a bayonet coupling structure or the like.

  When the motor unit 112 engaged with the focus ring 110 is driven, the focus ring 110 is rotationally driven. When the focus ring 110 rotates, the second lens barrel 102 moves in the optical axis direction due to the engaging action between the cam groove portion and the cam follower 109. Thereby, electric focus drive is performed.

  The sixth lens barrel 106 holds a relay lens as a sixth lens group, and is fixed to the rear end portion of the fixed cylinder 107 with a screw (not shown) from the thrust direction.

  The second lens barrel 102, the third lens barrel 103, the fourth lens barrel 104, and the fifth lens barrel 105 each hold a variable power lens as the second to fifth lens groups. The second lens barrel 102, the third lens barrel 103, the fourth lens barrel 104, and the fifth lens barrel 105 move in the direction of the optical axis, whereby zooming is performed.

  Here, the zoom drive mechanism will be described. Cam followers 109 are attached to the outer periphery of the second lens barrel 102, the third lens barrel 103, the fourth lens barrel 104, and the fifth lens barrel 105 at three positions every 120 ° in the circumferential direction. The cam followers 109 provided in the lens barrels 102 to 104 engage with a rectilinear groove 107A formed in the fixed cylinder 107 so as to extend in the optical axis direction. Further, it engages with the second, third and fourth cam groove portions 108A, 108B and 108C formed in the cam ring 108.

  A zoom ring 111 is attached to the end of the cam ring 108 (on the first lens barrel side) so as to be rotatable integrally therewith. The cam ring 108 is rotatable around the optical axis in a state where movement in the optical axis direction is prevented with respect to the fixed cylinder 107 by a bayonet coupling structure or the like.

  When the motor unit 112 engaged with the zoom ring 111 is driven, the zoom ring 111 is rotationally driven. When the zoom ring 111 rotates, the cam ring 108 rotates in a fixed position around the optical axis with respect to the fixed cylinder 107 integrally therewith. When the cam ring 108 rotates, the second, third, and fourth lens barrels 102 to 104 move in the optical axis direction by the engaging action of the cam groove portions 108A, 108B, and 108C and the cam follower 109. Thereby, electric zoom drive is performed.

  Next, the motor unit 112 will be described with reference to FIG. The motor unit 112 detects a motor main body 112A, a reduction gear box 112B that decelerates and outputs the rotation of the motor main body, a pulse plate 112C for expressing the drive of the motor as a rotation angle, and the rotation angle as a pulse signal. A substrate 112D holding a photo interrupter is provided.

  The output gear of the motor main body 112A and the input gear of the reduction gear box 112B are meshed with each other. As a result, the output torque and rotation speed of the motor main body 112A are converted into the intended output torque and rotation speed in the reduction gear box 112B and transmitted to the output gear of the reduction gear box 112B engaged with the focus ring 110 and the zoom ring 111. The Further, a pulse plate 112C having a disc shape and having a notch for each constant phase in the circumferential direction is attached to the output shaft of the motor body 112A. When the motor body 112A is driven, the pulse plate 112C also rotates. For this reason, when one arbitrary point of the diameter having the notch of the pulse plate 112C is viewed, the rotation angle of the motor body 112A can be detected without the notch. The reduction gear box 112B is provided with a substrate 112D to which a photo interrupter is attached so that the presence or absence of the notch can be read. The substrate 112D to which the photo interrupter is attached outputs the presence or absence of the notch as a pulse signal.

  The lens unit 100 of this embodiment detects the relative value of the focal position from the output of the substrate 112D to which the photo interrupter is attached, and moves the focal position until the switch 114 is activated each time the lamp is turned on, thereby setting the reference of the focal position. To detect. The focal position can be detected as a substantially absolute value by combining the focal position reference and the relative value of the focal position. In addition, since the focus position reference is detected each time the lamp is turned on, and the focus position adjustment error such as backlash is reset, the focus position may be out of the depth even if the absolute value of the focus position is not sufficiently detected. Absent.

  FIG. 4 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, it is confirmed whether or not there is a history that the user has moved the focal position at the time of previous lighting. If there is the history, the focal position is moved to detect the focal position reference until the switch 114 is operated, and the movement of the focal position and the adjustment of the focal position are started to detect the focal position reference. When there is no history, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are not performed.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 2]
In the second embodiment of the present invention, the approximate absolute value of the focal position is obtained by combining the relative value of the focal position from the substrate 112D to which the photo interrupter described in the first embodiment is attached and the reference of the focal position from the switch 114. Instead of detecting, the absolute position of the focal position is detected.

  FIG. 5 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, it is confirmed whether or not there is a history that the user has moved the focal position at the time of previous lighting. If there is the history, adjustment of the focal position is started. When there is no history, the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 3]
The third embodiment of the present invention has the same configuration as that of the first embodiment.

  FIG. 6 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, the temperature difference at the start of lighting this time is checked from when it was previously turned off. When the temperature difference is 5 ° C. or more, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are started. When the temperature difference is less than 5 ° C., the movement of the focal position and the adjustment of the focal position are not performed to detect the reference of the focal position.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 4]
The fourth embodiment of the present invention has the same configuration as that of the second embodiment.

  FIG. 7 shows a flowchart of an algorithm for determining whether or not the focal position correction of this embodiment is performed.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, the temperature difference at the start of lighting this time is checked from when it was previously turned off. When the temperature difference is 5 ° C. or more, adjustment of the focal position is started. When the temperature difference is less than 5 ° C., the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 5]
The fifth embodiment of the present invention has the same configuration as the first embodiment.

  FIG. 8 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, the time from the previous turn-off to the current turn-on is confirmed. When the time is two weeks or more, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are started. When the time is less than two weeks, the focus position is not moved and the focus position is not adjusted to detect the focus position reference.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 6]
The sixth embodiment of the present invention has the same configuration as that of the second embodiment.

  FIG. 9 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, the time from the previous turn-off to the current turn-on is confirmed. When the time is two weeks or more, the adjustment of the focal position is started. If the time is less than 2 weeks, the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 7]
The seventh embodiment of the present invention has the same configuration as that of the first embodiment.

  FIG. 10 shows a flowchart of an algorithm for determining whether to perform focus position correction of this embodiment.

  An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, the presence / absence of a lens replacement history from the previous turn-off to the current turn-on is confirmed. If there is a history, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are started. When there is no history, the focus position is not moved and the focus position is not adjusted to detect the focus position reference.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 8]
The eighth embodiment of the present invention has the same configuration as that of the second embodiment.

  FIG. 11 shows a flowchart of an algorithm for determining whether or not to perform focus position correction of this embodiment.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, the presence / absence of a lens replacement history from the previous turn-off to the current turn-on is confirmed. If there is a history, adjustment of the focal position is started. When there is no history, the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 9]
The ninth embodiment of the present invention has the same configuration as that of the first embodiment.

  FIG. 12 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, the presence / absence of a lamp replacement history from the previous turn-off to the current turn-on is confirmed. If there is a history, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are started. When there is no history, the focus position is not moved and the focus position is not adjusted to detect the focus position reference.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 10]
The tenth embodiment of the present invention has the same configuration as the second embodiment.

  FIG. 13 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, the presence / absence of a lamp replacement history from the previous turn-off to the current turn-on is confirmed. If there is a history, adjustment of the focal position is started. When there is no history, the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 11]
The eleventh embodiment of the present invention has the same configuration as the first embodiment.

  FIG. 14 shows a flowchart of an algorithm for determining whether or not the focus position correction of this embodiment is performed.

An algorithm for determining whether to move the focus position and adjust the focus position for detecting the reference of the focus position starts simultaneously with the start of lighting of the projector 300. First, it is confirmed whether or not there is a history of operation of the main power source from the previous turn-off to the current turn-on. If there is a history, the movement of the focal position and the adjustment of the focal position for detecting the reference of the focal position are started. When there is no history, the focus position is not moved and the focus position is not adjusted to detect the focus position reference.
With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

[Example 12]
The twelfth embodiment of the present invention has the same configuration as the second embodiment.

  FIG. 15 shows a flowchart of an algorithm for determining whether to perform focus position correction of the present embodiment.

  The algorithm for determining whether to perform the focus position correction starts simultaneously with the start of lighting of the projector 300. First, it is confirmed whether or not there is a history of operation of the main power source from the previous turn-off to the current turn-on. If there is a history, adjustment of the focal position is started. When there is no history, the focus position is not adjusted.

  With the above configuration and algorithm, when the user adjusts the focal position, image deterioration does not occur even if the temperature of the optical element and the optical element holding member changes. Can provide a projector whose focal position does not move.

DESCRIPTION OF SYMBOLS 100 Projection lens 100a Optical axis of projection lens 101 to 106 1st-6th lens barrel 107 Fixed cylinder 107A Lens barrel guide groove 108 Cam ring 108A, 108B, 108C, 108D Cam groove 109 2, 3, 4, 5 groups Cam follower 110 Focus ring 111 Zoom ring 112 Motor 112A Motor body 112B Reduction gear box 112C Pulse plate 112D Substrate 113 with photo interrupter attached Motor base 114 Switch 300 Projector

Claims (13)

A lens unit capable of adjusting at least one of focus and zoom and projecting an image;
A light source;
In a projection image display apparatus having an illumination optical system and a color separation / synthesis system that converts light from the light source into an image and guides it to a lens unit,
Projection-type image display comprising means for switching whether or not to perform focus position variation correction accompanying temperature change of at least one optical element of the lens unit, the illumination optical system, and the color separation / synthesis system apparatus. 2. The projection type image display apparatus according to claim 1, further comprising means for storing a history of the focus operation. 3. The apparatus according to claim 1, further comprising means for switching whether or not to perform focus position variation correction at the time of re-lighting according to a history of the focus operation between the previous lighting and the turning-off. Projection-type image display device. 2. The projection type image display apparatus according to claim 1, further comprising means for storing a history of the temperature of the optical element. 5. The projection type image display device according to claim 1, further comprising means for switching whether or not to perform focus position variation correction depending on a temperature difference between optical elements when the light is turned off last time and when lighting is started this time. . 2. The projection type image display device according to claim 1, further comprising means for storing a time from turning off to relighting. 7. The projection type image display apparatus according to claim 1, further comprising means for switching whether or not the focus position variation correction is performed according to a time from the previous turn-off to the current turn-on. 2. The projection type image display device according to claim 1, further comprising means for storing a history of lens exchange. 9. The projection type image display apparatus according to claim 1, further comprising means for switching whether or not to perform focus position variation correction according to a history of lens exchange. 2. The projection type image display apparatus according to claim 1, further comprising means for storing a lamp replacement history. 11. The projection type image display device according to claim 1, further comprising means for switching whether or not the focal position variation correction is performed according to a history of lamp replacement. 2. The projection type image display device according to claim 1, further comprising means for storing a history of operation of the main power source. 13. The projection type image display apparatus according to claim 1, further comprising means for switching whether or not the focus position variation correction is performed according to a history of operation of the main power source.