JP2011232474A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector which can correct an out-of-focus image over an entire screen when the image is displayed from an oblique direction with respect to the screen.SOLUTION: The projector comprises a posture adjustment device 16 which holds a projector lens 15 which projects an image displayed on a LCD to a screen so that the posture of the projection lens 15 can be changed. The posture adjustment device 16 comprises a holding frame 31 which is formed in a U-shape and holds the projector lens 15 rotatably around an X-axis 42 that is orthogonal to an optical axis 41, a first driven gear 32 which is held by the holding frame 31 and rotates around the X-axis 42, a first driving gear 34 which is rotated by a first motor 33, a rotation support panel 37 to which the holding frame 31 and the first motor 33 are fixed, at one end of which a second driven gear 35 is formed, and which is rotatably mounted on a casing with a shaft 36 whose center is a Y-axis 43 that is orthogonal to the optical axis 41 and the X-axis 42, and a second motor 39 which is provided with a second driving gear 38 engaged with the second driven gear 35 and which is fixed to the casing.

Description

  The present invention relates to focus adjustment of an image projected obliquely on a screen, and more particularly to a projector that corrects blurring of an entire image including four corners.

  2. Description of the Related Art There is known a projector that projects light having an image added thereto by a light modulation device such as an LCD or DMD onto a screen and displays the image on the screen. In the projector, the light (illumination light) emitted from the light source device is given an image according to the image signal (image information) by the light modulation device (image forming device), and is emitted from the projection lens as image light. Is projected on the screen. If the optical axis of the projection lens is perpendicular to the screen, the image displayed on the light modulation device is enlarged as it is and projected onto the screen. Usually, however, the screen is often placed above the projector. For this reason, the optical axis of the projection lens is inclined obliquely upward with respect to the screen, and the projected image is projected into a trapezoid on the screen.

  When the projector is placed facing the screen and an image is projected obliquely upward, the rectangular image becomes an isosceles trapezoid. In Patent Document 1 below, a distortion amount of a trapezoidal distortion is measured from a trapezoidal image projected on a screen, an image on the liquid crystal panel is corrected based on a correction amount corresponding to the measured distortion amount, and the correction rate ( A projector is shown that enlarges at an enlargement ratio corresponding to (reduction ratio), corrects the long side to be a rectangular image having the same size as the original trapezoid image, and projects the image onto a screen. Further, a projector that detects a projection angle by an installation angle detector and performs keystone correction is described in Patent Document 2 below. Patent Document 3 below describes a projector that can switch between a mode for automatically correcting with respect to the upper side of the projected trapezoid and a mode for manually correcting with respect to the lower side of the projected trapezoid.

JP 2001-249401 A JP 2001-339671 A JP 2005-114906 A

  However, even if the trapezoidal image is corrected so that it appears as a rectangle on the screen, the distance from the projection lens to the screen differs at the four corners of the image. When projected upward, the focus position is different between the upper side and the lower side, so if one is focused, the other will be out of focus.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention can correct out-of-focus when projecting an image from an oblique direction with respect to a screen with a simple operation or without using a dedicated device or a complicated device. Propose.

  A projector according to the present invention is a projector including a projection lens that projects light with an image onto a screen to display the image, and an image forming apparatus having an image forming surface on which the image is formed, The projection lens is rotatably held around two axes perpendicular to the optical axis and orthogonal to each other, and an attitude adjusting device for rotating the held projection lens is provided. The posture adjusting device may be configured to rotate the projection lens in accordance with an operation of a tilt operation member provided in the housing.

  Five specific images displayed at the center and four corners of the image forming surface, an imaging device that captures the specific image displayed on the screen, and a contrast of the specific image captured by the imaging device are detected. It is preferable to include a contrast detection circuit and a control circuit that drives the posture adjustment device so that the contrast values of the five specific images obtained by the contrast detection circuit are substantially the same. A light source device that emits infrared light may be provided, and the specific image may be projected onto the screen by the infrared light.

  An image correction circuit that receives an operation signal from a screen shape correcting member provided in a housing and expands or contracts a display size of an image formed on the image forming surface of the image forming apparatus with respect to a rotation direction of the projection lens; You may make it prepare. The projector may be mounted on a mobile phone, and the infrared communication light source of the mobile phone may also be used as a light source device that irradiates the specific image.

  The projector device according to the present invention can easily focus on the entire image captured on the screen, so that an image that is not out of focus can be seen even if it is projected obliquely on the screen.

It is a figure which shows the structure of the projector by this invention. It is explanatory drawing projected on a screen. It is a schematic diagram of a light source device. It is a block diagram explaining the structure of a projector. It is a perspective view of the attitude | position adjustment apparatus which attached the projection lens. It is a figure explaining rotation of a projection lens. It is a figure which shows a rectangular image. It is a figure which shows a trapezoid image. It is a block diagram which shows the structure of another embodiment. It is a schematic diagram of another light source device. It is a perspective view of the attitude | position adjustment apparatus which attached LCD. It is a schematic diagram which shows the structure in the case of using a projection lens also as an imaging lens. It is a schematic diagram which shows the structure in case the infrared communication LED of a mobile telephone is combined for chart display.

  As shown in FIG. 1, an ultra-compact and portable projector 10 according to the present invention includes a light source device 13, a liquid crystal display device (image forming device) (hereinafter simply referred to as an LCD) 14, a housing 11 having a substantially rectangular parallelepiped shape, A projection lens 15, an attitude adjustment device 16 and a control device 17 are accommodated. On the top surface of the housing 11, a zoom dial 21, a light amount adjustment dial 22, a focus dial 23, an up / down pin tone dial (tilting operation member) 24, a left / right pin. An adjustment dial (tilting operation member) 25 and a screen correction dial (screen shape correction member) 26 are provided. The light emitted from the light source device 13 is provided with an image on the image forming surface 18, emitted from the projection lens 15, and projected onto the screen 20 (see FIG. 2).

  As shown in FIG. 3, the light source device 13 includes LEDs 51 that emit light of three colors of RGB. The light emitted from the R (red) LED 51 is reflected by the dichroic mirror 52, and the light emitted from the G (green) LED 51 is reflected by the dichroic mirror 53 and passes through the dichroic mirror 52. The light emitted from the B (blue) LED 51 passes through the dichroic mirrors 52 and 53, and the light of the three colors RGB is emitted on the same optical axis.

  As shown in FIG. 4, the control device 17 includes a CPU 63, a RAM 68, a focus circuit 65, a motor drive circuit 66, and an image correction circuit 67. The CPU 63 sequentially displays RGB three-color images on the image forming surface 18 of the LCD 14, and emits the respective lights from the three-color LEDs 51 in synchronization with the three-color images. In addition, the size of an image projected on the screen 20 upon receipt of an operation signal from the zoom dial 21 is adjusted, or the brightness of the image projected onto the screen 20 is adjusted upon receipt of an operation signal from the light amount adjustment dial 22. To do. The focus circuit 65 operates a focus adjustment mechanism (not shown) of the projection lens 15 in accordance with the operation of the focus dial 23 to adjust the focus of the center portion of the image projected on the screen 20. Since these are well-known techniques, detailed description is omitted.

  As shown in FIG. 5, the attitude adjustment device 16 includes a U-shaped holding frame 31 that holds the projection lens 15 rotatably around an X axis 42 that is orthogonal to the optical axis 41, and an X axis that is supported by the holding frame 31. The first driven gear 32 that rotates about 42, the first drive gear 34 that is rotated by the first motor 33, the holding frame 31 and the first motor 33 are fixed, and the second driven gear 35 is provided at one end side. A rotation support plate 37 formed and rotatably attached to the housing 11 by a shaft 36 centered on a Y axis 43 orthogonal to the optical axis 41 and the X axis 42, and a second driven gear 35 meshes with the second driven gear 35. A drive gear 38 is attached to the rotary shaft, and the second motor 39 is fixed to the casing 11.

  The first motor 33 is rotated by the operation of the up / down pin tone dial 24, and the projection lens 15 is rotated around the X axis 42 so that the vertical inclination of the optical axis 41 is adjusted. The second motor 39 is rotated by the left / right pin tone dial 25 to rotate the projection lens 15 around the Y axis 43. The rotation direction and the rotation angle of the projection lens 15 by the first motor 33 and the second motor 39 are recorded in the RAM 68, respectively. The LCD 14 in the embodiment may be a DMD or another image forming apparatus.

  The image correction circuit 67 changes the display size of the image formed on the image forming surface 18 of the LCD 14 in accordance with the operation of the screen correction dial 26 provided on the housing. For example, when the RAM 68 records that the projection lens 15 is rotated downward about the X axis 42 by the first motor 33, it is displayed on the image forming surface 18 when the screen correction dial 26 is turned. The lower side of the image is shrunk, and the upper side of the image projected on the screen 20 is shrunk and displayed. Further, when the RAM 68 records that the projection lens 15 is rotated leftward about the Y axis 43, the left side of the image displayed on the image forming surface 18 is contracted when the screen correction dial 26 is turned. The right side of the image projected on the screen 20 is shrunk and displayed.

  Next, the operation of the present invention will be described. As shown in FIG. 2, the projector 10 placed on the desk 47 so as to face the screen 20 is often located above the projector 10. Is done. A rectangular image 44 (see FIG. 7) displayed on the image forming surface 18 of the LCD 14 is projected onto the screen 20 by the projection lens 15, and the image light projected from the projection lens 15 is irradiated obliquely onto the screen 20. Therefore, the rectangular image 44 is a trapezoidal image 45 (see FIG. 8), with the upper side farther from the lower side being longer than the lower side. When the focus dial 23 is turned, the focus adjustment mechanism is activated to move the projection lens 15 in the direction of the optical axis 41, and the focus adjustment of the center portion of the image projected on the screen 20 is performed.

  As shown in FIG. 6, while operating the up / down pin tone dial 24 while viewing the image on the screen 20, the projection lens 15 is rotated in the up / down direction. When the out-of-focus state at the four corners of the image shown on the screen 20 is improved, the operation of the up / down pin tone dial 24 is stopped. Further, when the image is projected obliquely from either the left or right direction with respect to the screen 20, a trapezoidal image with a long left or right side is formed, so the left and right pin tone dial 25 is operated to move the projection lens 15 in either the left or right direction. Rotate to Further, a resolution chart (specific image) 55 to 59 for focus adjustment is displayed on the image forming surface 18, and the focus dial 23, the vertical pin tone dial 24, etc. are operated while viewing the resolution charts 55 to 59 on the screen. Then, focusing at the center of the screen or focusing on the entire screen may be performed.

  As shown in FIG. 9, when the entire screen is focused, the screen correction dial 26 is operated to correct the image projected on the screen 20. For example, when the RAM 68 records that the projection lens 15 is rotated downward about the X axis 42 by the first motor 33, it is displayed on the image forming surface 18 when the screen correction dial 26 is turned. The image size is continuously reduced as it approaches the lower side with respect to the upper side of the image forming surface 18. Accordingly, the image size on the screen 20 is gradually reduced toward the upper side with respect to the lower side, so that the image size of the entire screen becomes substantially the same by adjusting the screen correction dial 26. Can be arranged.

  In the above example, when changing the image size on the image forming surface 18, it is possible to enlarge the upper side with reference to the lower side, or to reduce the lower side in parallel with the enlargement of the upper side. is there. When the projection lens 15 is rotated leftward about the Y axis 43, the image size on the image forming surface 18 is gradually reduced toward the left side with reference to the right side in conjunction with the operation of the screen correction dial 26. Then, the image size in the left-right direction on the screen 20 can be adjusted.

  Next, although another embodiment is described, the same components as those of the above embodiment are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 10, the projector 50 includes a housing 11 in which a light source device 71, an LCD 14, a projection lens 15, an attitude adjustment device 16 and a control device 70 are housed. (See FIG. 1). As shown in FIG. 11, the light source device 71 includes an LED 51 that emits light of three RGB colors and an LED 72 that emits infrared light (IR). Light emitted from the LED 51 of R (red), G (green), and B (blue) is reflected by the dichroic mirrors 52, 53, and 54, respectively, and infrared light (IR) emitted from the LED 72 is reflected from the dichroic mirrors 52, 53. , 54 and emitted on the same optical axis.

  When the power supply of the projector 50 is turned on, infrared light is emitted from the LED 72, and a rectangular image 44 displayed on the image forming surface 18 of the LCD 14 is projected on the screen 20. As shown in FIG. 7, resolution charts (specific images) 55 to 59 are displayed in the rectangular image 44 at five locations in the center and four corners. The rectangular image 44 appears on the screen 20 like a trapezoidal image 45 shown in FIG. 8 (although it is invisible because it is infrared light). The projector 50 includes a camera (imaging device) 60 (see FIG. 10) that captures an image projected on the screen 20. The resolution charts 55 to 59 projected on the screen 20 by the photographing lens 61 of the camera 60 are stored in the CCD 62. Make an image.

  As illustrated in FIG. 10, the control device 70 includes a contrast detection circuit 64 that detects the contrast of the resolution charts 55 to 59 from the image captured by the camera 60. The CPU 73 transmits the value of the resolution chart 55 detected by the contrast detection circuit 64 to the focus circuit 65, and the focus circuit 65 drives the projection lens 15 along the direction of the optical axis 41 to project the image projected on the screen 20. Adjust the focus of the center of the. The CPU 73 instructs the motor drive circuit 66 while monitoring the contrast values of the resolution charts 56 to 59, rotates the first motor 33 and the second motor 39 to drive the attitude adjustment device 16, and the resolution chart 56. The attitude of the projection lens 15 is adjusted so that the contrast value of .about.59 is the best. After focusing on the entire screen, the screen correction dial 26 is operated to adjust the display image size on the image forming surface 18 to adjust the size of the image projected on the screen 20 in the same manner as in the previous embodiment. It ’s fine.

  As shown in FIG. 12, a half mirror 75 may be disposed between the LCD 14 and the projection lens 15 so that the projection lens 15 is also used as a photographing lens of the camera 60. The light source device 13 is provided with an LED 72 that emits infrared light, and projection of the resolution charts 55 to 59 is performed with infrared light, so that the trapezoid correction of the image can be performed without any particular attention of the image observer. However, the resolution charts 55 to 59 may be projected by the color LED 51 for image display without providing the LED 72. In that case, the camera 60 need not also be for infrared.

  Further, the projector according to the present invention may be mounted on a mobile phone. In that case, as shown in FIG. 13, an infrared LED 77 used for the power source for infrared communication may be used for projecting the resolution charts 55 to 59. When the infrared light emitted from the infrared LED 77 incorporated in the light source device 80 is used for projection of the resolution charts 55 to 59, the LCD 14 is irradiated with the movable mirror 82 in the retracted position, and used as an infrared communication power source. When used, it is preferable that the movable mirror 82 is moved to the reflection position to reflect infrared light, and further reflected by the mirror 83 to be emitted from the mobile phone. A half mirror may be used instead of the movable mirror 82.

10, 50 Projector 11 Housing 13, 71, 80 Light source device 14 LCD (liquid crystal display device, image forming device)
DESCRIPTION OF SYMBOLS 15 Projection lens 16 Posture adjustment apparatus 17,70 Control apparatus 18 Image formation surface 20 Screen 21 Zoom dial 22 Light quantity adjustment dial 23 Focus dial 24 Vertical pin tone dial (tilting operation member)
25 Left and right pin-tone dial (tilting operation member)
26 Screen correction dial (screen shape correction member)
31 Holding frame 32 First driven gear 33 First motor 34 First drive gear 35 Second driven gear 36 Axis 37 Rotation support plate 38 Second drive gear 39 Second motor 41 Optical axis 42 X axis 43 Y axis 44 Rectangular image 45 Trapezoidal image 51 LED (LED that emits one of RGB light)
52 Dichroic mirror (reflects R light)
53 Dichroic mirror (reflects G light)
54 Dichroic mirror (reflects B light)
55-59 Resolution chart (specific image)
60 Camera (imaging device)
61 Shooting lens 62 CCD
63 CPU
64 Contrast detection circuit 65 Focus circuit 66 Motor drive circuit 67 Image correction circuit 68 RAM
72 LEDs (LEDs that emit infrared light (IR))
73 CPU (control circuit)
75 Half mirror 77 Infrared LED (Infrared LED used for power source for mobile phone infrared communication)
82 Movable mirror 83 Mirror

Claims (6)

In a projector including a projection lens that projects light with an image onto a screen to display the image, and an image forming apparatus having an image forming surface on which the image is formed.
A projector comprising: an attitude adjusting device that holds the projection lens rotatably about two axes that are perpendicular to the optical axis and perpendicular to each other, and that rotates the projection lens held.   The projector according to claim 1, wherein the posture adjusting device rotates the projection lens in accordance with an operation of a tilt operation member provided in a housing. Five specific images displayed at the center and four corners of the image forming surface;
An imaging device that captures the specific image displayed on the screen;
A contrast detection circuit for detecting a contrast of the specific image captured by the imaging device;
A control circuit that drives the posture adjustment device so that the contrast values of the five specific images obtained by the contrast detection circuit are substantially the same;
The projector according to claim 1, further comprising:   The projector according to claim 3, further comprising: a light source device that emits infrared light, wherein the specific image is projected onto the screen by infrared light emitted from the light source device.   5. The projector according to claim 4, wherein the projector is mounted on a mobile phone, and the light source for infrared communication of the mobile phone is also used as the light source device.   An image correction circuit that expands or contracts a display size of an image formed on the image forming surface with respect to a rotation direction of the projection lens in accordance with an operation of a screen shape correcting member provided in a housing. The projector according to claim 1.

Images