JP4401499B2 - Projection lens support device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection lens support device used in a projector that magnifies and projects an image.
[0002]
[Prior art]
As a projection lens support device used for a liquid crystal projector, a method of changing a magnification by exchanging a lens group is known as a device that is generally used. By using this interchangeable projection lens support device, it is possible to select a lens group having an appropriate magnification according to the size of the screen and the distance to the screen.
[0003]
On the other hand, some liquid crystal projectors include a lens moving device that adjusts the lens group by moving the lens group up and down while adjusting the position of the image projected on the screen in the vertical direction.
[0004]
It is desirable to be able to adjust the magnification and the vertical projection position of the liquid crystal projector by combining this lens moving device and the above-described exchange-type projection lens support device.
[0005]
[Problems to be solved by the invention]
However, when the exchange method is adopted, the effective diameter varies depending on the type of lens, so if the moving range of the lens moving device is fixed to a setting that matches the lens with a large effective diameter, a lens with a small effective diameter is used. If the upper and lower limits are moved, the projection light does not reach the screen in the peripheral portion of the projection range, and only that portion becomes dark. Further, if the setting is fixed according to a lens having a small effective diameter, the moving range of the lens group having a large effective diameter is limited, and thus the lens characteristics cannot be utilized.
[0006]
The present invention has been made in consideration of the above circumstances, and provides a projection lens support device that adopts an exchange method and enables adjustment of the projection position in the vertical direction within a movement range that is adapted to each lens. With the goal.
[0007]
[Means for Solving the Problems]
To achieve the above object, in the projection lens support device of the present invention, in the projection lens support device that is provided in the image projector and supports the lens barrel in which the projection lens is incorporated, the lens barrel is detachable. Mount base to be mounted, signal reading means for reading the lens identification signal indicating the type of the projection lens from the signal part of the lens barrel mounted on the mount base, and the mount base moved in a plane perpendicular to the optical axis Mount base moving means to be moved, and movement range regulating means for regulating the movement range of the mount base by the mount base moving means based on the lens identification signal obtained from the signal reading means.
[0008]
The movement range regulating means includes a storage means that associates movement range data of the mount base for each of a plurality of types of lens identification signals, a position sensor that detects a movement position of the mount base, and a mount that is detected by the position sensor. It is preferable that the apparatus further comprises control means for controlling the operation of the mount base moving means by comparing the movement position of the base with movement range data read from the storage means.
[0009]
Further, it is preferable that the signal reading means is constituted by a reflection type photosensor, and the signal portion is a light reflection signal portion in which a reflection pattern is changed depending on the type of projection lens.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example in which the projection lens support device of the present invention is applied to a liquid crystal projector will be described with reference to the drawings. The liquid crystal projector 11 shown in FIG. 2 includes a box-shaped cabinet 21 and a lens barrel 23 attached to the cabinet 21. As the lens barrel 23, a plurality of types including different lens groups 44 are prepared, and one selected from these is a main body exposed from the opening 22 formed on the front surface of the cabinet 21. Attached to the side mount 34. Further, the cabinet 21 is provided with a power switch 24, an up switch 25, a down switch 26, and an image input terminal (not shown). As shown in FIG. 3, the liquid crystal projector 11 raises or lowers the position of the lens barrel 23 that projects an image on the screen 10 by pressing an up switch 25 or a down switch 26. The position of the image projected on the screen 10 is adjusted.
[0011]
FIG. 1 is an exploded perspective view showing the configuration of the projection lens support device of the present invention. The projection lens device 30 includes a lens barrel 23, a mount base member 31, a guide shaft 32, and a potentiometer 33. The
[0012]
The mount base member 31 is formed by integrally forming a substantially disc-shaped main body side mount portion 34 and an arm portion 35 protruding from the outer peripheral surface thereof. The main body side mount part 34 is provided with a bayonet groove 36, a lock pin 37, and sensor parts PH1 to PH3. A plurality of bayonet grooves 36 are provided in the circumferential direction centered on the optical axis L and separated by a predetermined distance. The lock pin 37 is movable between a protruding position protruding toward the screen 10 (see FIG. 3) along the direction of the optical axis L and a retracted position retracted inside the main body side mount portion 34. It is biased toward the protruding position by a spring (not shown) incorporated therein.
[0013]
A reflection type photosensor 38 is used for the sensor portions PH1 to PH3, and the type of the lens barrel 23 is discriminated by this. FIG. 4 shows a cross-sectional view of the main parts of the sensor parts PH1 to PH3. FIG. 4 shows a cross section in the circumferential direction about the optical axis L. The photo sensor 38 is a package of a light projecting unit and a light receiving unit. The light projecting unit 39 includes a light emitting diode 39a such as an IRED that emits infrared light and a light projecting lens 39b. The phototransistor 40a and the light-receiving lens 40b have the light-receiving sensitivity matched to the light emitted from the light-emitting diode 39a. A cylindrical mounting portion 34a is integrally formed on the inner wall of the main body side mounting portion 34, and the photosensor 38 is fixed to the mounting portion 34a with an adhesive. When the main body side mount portion 34 is a metal part, the photo sensor 38 may be fixed with screws using a holding plate or the like.
[0014]
The arm portion 35 is attached to a guide shaft 32 that is substantially perpendicular to the optical axis L. Thereby, the mount base member 31 is movable up and down along the guide shaft 32. The guide shaft 32 is fixed to the cabinet 21 via support plates 42 and 43 provided above and below the guide shaft 32.
[0015]
A protrusion 41 is formed on the arm portion 35 at a position that does not interfere with the guide shaft 32. The protrusion 41 is engaged with a long hole 43 a provided integrally with the support plate 43. A slider 33a constituting a potentiometer 33 is provided at the tip of the protrusion 41, and the slider 33a slides on a resistor 33b provided in the back of the long hole 43a. The potentiometer 33 configured in this manner functions as a variable resistor whose resistance value increases as the slider 33a goes upward and decreases as it goes downward. When a constant current is passed through the potentiometer 33, the voltage value applied to the potentiometer 33 changes in proportion to the displacement of the slider 33a. In this way, the potentiometer 33 functions as a position detector that detects the position of the mount base member 31 by replacing it with the voltage value.
[0016]
The lens barrel 23 includes a lens group holding unit 27 and a lens side mount unit 28. In the lens barrel 23 in which a plurality of types are prepared, the configuration of the lens side mount unit 28 is common to all types, but the configuration of the projection lens group 44 built in the lens group holding unit 27 is different for each type. Is different.
[0017]
The lens-side mount portion 28 is provided with a bayonet protrusion 45 and a lock hole 46. The same number of bayonet protrusions 45 as the bayonet grooves 36 are provided, and these bayonet protrusions 45 are fitted into the bayonet grooves 36. When the bayonet is connected to the lock hole 46, the lock pin 37 enters. In addition, the lens group holding unit 27 is provided with an unlock operation unit 47. The unlocking operation unit 47 includes a knob 47a and a release pin 47b that are integrally formed. The knob 47a protrudes from the outer periphery of the lens group holding unit 27 and can be operated from the outside. Further, the release pin 47 b is formed to extend toward the lock hole 46. The unlocking operation unit 47 allows the release pin 47b to enter the lock hole 46 and move the lock pin 37 to the retracted position, and allow the lock pin 37 to retract from the lock hole 46 and move to the protruding position. It is provided so as to be movable between the retracted position.
[0018]
In addition, a reflection sheet 48 is attached to the lens side mount portion 28 at a position facing the sensor portions PH1 to PH3. As shown in FIG. 4, the reflection sheet 48 is divided into three reflection surfaces 49 so as to correspond to the sensor portions PH1 to PH3. The reflective surface 49 is coated with white or black paint, respectively.
[0019]
When the lens barrel 23 is attached to the main body side mount portion 34, the reflection sheet 48 is read by the sensor portions PH1 to PH3. FIG. 5 is a circuit diagram showing a configuration of the sensor units PH1 to PH3. The sensor units PH1 to PH3 are driven by a movement control circuit 56 (see FIG. 6) described later. First, the power source is connected to the terminal 51 by the movement control circuit 56. Thereby, the light emitting diode 39a emits infrared rays toward the reflection surface 49, and the phototransistor 40a receives the reflected light reflected by the reflection surface 49. Then, a current corresponding to the amount of reflected light flows through the phototransistor 40a. When the reflective surface 49 is white, the amount of reflected light is high, and a high (H) level current flows through the phototransistor 40a. When the reflective surface 49 is black, the amount of reflected light is low and low (L ) Level current flows. In this way, the sensor units PH1 to PH3 read the reflection surface 49, convert it to a high (H) level or low (L) level signal, and send it to the movement control circuit 56 connected to the terminal 52. .
[0020]
FIG. 6 shows an outline of the electrical configuration of the liquid crystal projector 11. The liquid crystal projector 11 is roughly divided into a projection lens support device control unit 53 and a liquid crystal display unit 54.
[0021]
The movement control circuit 56 manages the electrical operation of the projection lens support device controller 53 as a whole, drives the motor driver 57 while pressing the raising switch 25 or the lowering switch 26, and mount base member When 31 is lifted or lowered along the guide shaft 32 and the pressing is released, the mount base member 31 is stopped. Further, the position of the mount base member 31 in the vertical direction is detected by the position detection potentiometer 33.
[0022]
Further, the movement control circuit 56 reads the reflection sheet 48 by the sensor units PH <b> 1 to PH <b> 1 to determine the type of the lens barrel 23. The movement control circuit 56 receives the signal sent from the sensor units PH1 to PH3 as a 3-bit determination code, and determines the type of the lens barrel 23. The determination code recognizes up to eight types of lens barrels 23 by setting each bit to “1” (“H level”) or “0” (“L level”). When the movement control circuit 56 receives the determination code, the movement control circuit 56 reads information on the lens barrel 23 corresponding to the determination code from the memory 58. This information is the upper limit and lower limit positions when the mount base member 31 moves. Since the lens barrel 23 has a built-in projection lens group 44 with different effective diameters depending on the magnification specifications, the range that can be projected differs depending on the type. For this reason, the upper limit and the lower limit are set so that the lens barrel 23 attached to the mount base member 31 moves within a projectable range.
[0023]
In the liquid crystal display unit 54, by connecting a video player, a microcomputer, or the like to the image input terminal 61, image data is input from those external input devices to the liquid crystal display control circuit 59, and the image data is based on the image data. Then, the liquid crystal display control circuit 59 drives the LCD driver 62 to display a moving image, computer graphics, or the like on the liquid crystal panel 63.
[0024]
Next, the operation of the above configuration will be described. When performing projection, the lens barrel 23 is opposed to the screen 10, and the liquid crystal projector 11 is installed at an appropriate distance from the screen 10. In order to project an image displayed on the liquid crystal panel 63, for example, a video player is connected to the image input terminal 61.
[0025]
Further, the power is turned on and the video player is played back. The light emitted from the projection light source 64 is directed to the liquid crystal panel 63 by the condenser lens 66 and illuminates the image displayed on the liquid crystal panel 63. The illumination light is directed to the projection lens group 44 built in the lens barrel 23, and an image is projected onto the screen 10.
[0026]
Thereafter, the projection magnification and the upper and lower projection positions are adjusted from the state of the image projected on the screen 10. First, in order to adjust the magnification, the lens barrel 23 is replaced and adjusted. Then, after selecting an appropriate lens barrel 23 and attaching it to the main body side mount portion 34, the vertical projection position is adjusted.
[0027]
When the lock pin 37 enters the lock hole 46 and the coupling between the lens barrel 23 and the main body side mount portion 34 is locked, the sensor portions PH1 to PH3 start reading the reflection sheet 48. When the reflection sheet 48 is read and the type of the lens barrel 23 is determined, upper limit and lower limit position data when the mount base member 31 moves are read from the memory 58. When the raising switch 25 or the lowering switch 26 is pressed, the motor driver 57 is driven, and the mount base member 31 to which the lens barrel 23 is attached starts to move up and down along the guide shaft 32.
[0028]
The position of the mount base member 31 is detected by the potentiometer 33 and sent to the movement control circuit 56. When the mount base member 31 reaches the same position as the upper limit or lower limit position data read from the memory 58, the movement control circuit 56 stops driving the motor driver 55 and stops the mount base member 31. .
[0029]
Thus, since the upper and lower limit positions when the lens barrel 23 moves are controlled according to the type of the lens barrel 23, the lens barrel 23 is set to the upper limit as shown in FIG. In the projection range 67 of the image projected on the screen 10 when it is located, or in the projection range 68 of the image projected on the screen 10 when it is located at the lower limit, the projection light reaches the peripheral part, and is always A clear image can be seen.
[0030]
In the above embodiment, three sensor units and three corresponding reflective surfaces are provided, but the number is not limited to this number. For example, it is desired to further increase the number of lens barrels to be discriminated. The case can be dealt with by increasing the number of sensor units and the number of reflecting surfaces corresponding thereto.
[0031]
Furthermore, in the above embodiment, the projection lens support device of the present invention is used for a liquid crystal projector. However, the present invention is not limited to this, and for example, a CRT projector may be used, or a reflection for projecting an image of a transparent document. It can also be used for projectors and overhead projectors.
[0032]
【The invention's effect】
As described above, in the projection lens support device of the present invention, the lens identification signal indicating the type of the projection lens is read from the signal portion of the lens barrel, the type of the lens barrel is determined, and the type of the lens barrel is determined. The movement range data of the mount base member is read from the storage means, and the movement range of the mount base member is limited based on the movement range data. The projection position can be adjusted within the moving range.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a projection lens support device of the present invention.
FIG. 2 is an external perspective view of a liquid crystal projector to which the present invention is applied.
FIG. 3 is an explanatory diagram showing a projection range on a screen of a liquid crystal projector.
FIG. 4 is a cross-sectional view of a main part showing the structure of a sensor unit and a reflection sheet.
FIG. 5 is a circuit diagram showing a configuration of a sensor unit.
6 is a block diagram showing an outline of an electrical configuration of the liquid crystal projector shown in FIG. 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Liquid crystal projector 21 Cabinet 22 Opening part 23 Lens barrel 24 Power switch 25 Up switch 26 Down switch 27 Lens group holding part 28 Lens side mount part 30 Projection lens support apparatus 31 Mount base member 32 Guide shaft 33 Potentiometer 34 Main body side Mount part 38 Photosensor 39 Light projecting part 39a Light emitting diode 40 Light receiving part 40a Phototransistor 48 Reflecting sheet 49 Reflecting surface

Claims (3)

In a projection lens support device that is provided in an image projector and supports a lens barrel in which a projection lens is incorporated,
A mount base to which the lens barrel is detachably mounted; signal reading means for reading a lens identification signal representing a type of projection lens from a signal portion of the lens barrel mounted on the mount base; and Mount base moving means for moving in a plane perpendicular to the axis, and movement range regulating means for regulating the movement range of the mount base by the mount base moving means based on the lens identification signal obtained from the signal reading means. A projection lens support device characterized by that. The movement range regulating means includes a storage means that associates the movement range data of the mount base for each of a plurality of types of lens identification signals, a position sensor that detects the movement position of the mount base, and a mount that is detected by the position sensor. 2. The projection lens support according to claim 1, further comprising a control unit that controls the operation of the mount base moving unit by comparing a moving range of the base with movement range data read from the storage unit. apparatus. 3. The projection lens support device according to claim 2, wherein the signal reading means is constituted by a reflection type photosensor, and the signal portion is a light reflection signal portion in which a reflection pattern is changed depending on the type of the projection lens.

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