JP2017203920A - Image projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projector which can adjust a projection position of a projected image formed on a projection target surface without displacing the focus.SOLUTION: The present invention relates to an image projector for projecting a picture signal and forming a projected image on a projection target surface, the image projector including: shifting means for shifting the projection position of the projected image; focusing means for adjusting the focus position of the projected image; state acquisition means for acquiring the state of the projected surface; and control means for controlling the focus position by the focusing means based on the amount of shift and the acquired state acquired by the state acquisition means when the shifting is performed by the shifting means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection apparatus.

  The image projection apparatus displays a projection image by projecting light modulated by a light modulation element (also referred to as an image forming element) such as a liquid crystal panel onto a projection surface such as a screen by a projection optical system. In order for the user to display a projected image in a desired area on the projection surface, the projection conditions such as the orientation and tilt of the image projection device are adjusted, and the projection optical system is adjusted to adjust the projection size and position. It is necessary to do.

  Patent Document 1 discloses a lens shift mechanism that includes a mechanism that translates a condenser lens and a projection lens in the height direction of an image display surface of a display panel. Further, Patent Document 2 discloses a projection display device that corrects image distortion in accordance with the amount of lens shift in order to suppress screen distortion that occurs when tilt projection is performed.

JP 05-027324 A JP 2003-195416 A

  If the method of patent document 1 is used, it is possible to adjust a projection position, without changing the direction and position of an image projection apparatus. If the method of Patent Document 2 is used, it is possible to continue correcting image distortion correctly even if lens shift is performed in a state where image distortion generated when tilt projection is performed.

  However, the methods of Patent Document 1 and Patent Document 2 do not consider the case where readjustment of the focus position is necessary after adjusting the projection position. Therefore, when the projection position is adjusted, the focus shifts to a position unintended by the operator. May end up.

  An object of the present invention is to provide an image projection apparatus that can adjust the projection position of a projection image formed on a projection surface without shifting the focus.

In order to achieve the above object, an image projection apparatus according to an aspect of the present invention includes:
An image projection apparatus that projects a video signal and forms a projection image on a projection surface, a shift unit that shifts a projection position of the projection image, a focus unit that adjusts a focus position of the projection image, and the target A focus position is controlled by the focus unit based on a state acquisition unit that acquires a state of the projection surface, and a shift amount and a state acquired by the state acquisition unit when a shift is performed by the shift unit. And a control means.

  According to another aspect of the present invention, an image projection apparatus is the image projection apparatus according to claim 1, wherein the control unit sets a focus position so that a specific position of the projection image is focused on the projection surface. It is characterized by adjusting.

  According to another aspect of the present invention, an image projection apparatus is the image projection apparatus according to claim 2, wherein the image projection apparatus includes a position setting unit for setting the specific position.

  According to another aspect of the present invention, there is provided the image projection device according to any one of claims 1 to 3, wherein the control unit is configured such that the focus position substantially matches an average projection depth of the projection image. It controls to do.

  According to another aspect of the present invention, an image projection apparatus according to any one of claims 1 to 4, further comprising a correction unit that corrects geometric distortion, wherein the state acquisition unit includes: The tilt state of the projection surface is obtained based on the correction amount of the correction means.

  ADVANTAGE OF THE INVENTION According to this invention, the image projection apparatus which can adjust the projection position of the projection image formed on the to-be-projected surface without shifting a focus can be provided.

1 is a block diagram showing a configuration of a projector that is an embodiment of the invention Flowchart of processing in the embodiment of the present invention The figure which shows the situation where the projector is projecting the picture The figure which shows the situation where the projector adjusted the projection position Explanatory drawing of the focus correction performed by the projector 100 in the embodiment of the present invention

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[Example]
First, with reference to FIG. 3 and FIG. 4, it will be described that “the focus shifts when the projection position is adjusted”, which is a problem to be solved in the present embodiment.

  FIG. 3 is a diagram showing a state before adjusting the projection position of the projector.

  In FIG. 3, the projector 100 projects an image without facing the screen S. The projector 100 does not adjust the projection position, the center of the projection image coincides with the optical axis (broken line), and the focus is set so that the center of the projection image is in focus at a point o formed on the screen S. Has been adjusted. That is, the focus is set so as to focus on the distance z between the projector 100 and the point o, and the plane F indicated by the double chain line is the in-focus plane.

  Next, FIG. 4 is a diagram showing a state after the projection position is adjusted (shifted to the left side in FIG. 3) from FIG.

  Since the projection position is shifted to the left with respect to FIG. 3, the center of the projection image changes from the optical axis (broken line) to a dotted line inclined to the left, and the center of the projection image is the point o ′ on the screen S. Is formed. On the other hand, even if the projection position is adjusted, the focus position does not change, so the focused surface remains the surface F.

  For this reason, when focusing on the center of the projected image, it seems that the focus is shifted from the center of the screen when the projection position is adjusted. As described above, the function for adjusting the projection position is generally based on the premise that the projector and the screen are facing each other. Therefore, if the projected surface is not facing the projector or is not a flat surface, the focus is operated. May shift to a position unintended by the person.

  Next, with reference to FIG. 1, a schematic configuration of a projector 100 that is an image projection apparatus in the present embodiment will be described.

  The video processing unit 10 is provided with a terminal for inputting a video signal such as a composite terminal or an HDMI (registered trademark) terminal, and a receiver IC for receiving a video signal input through these terminals. . The video processing unit 10 generates a video signal obtained by performing image processing such as brightness correction, contrast correction, gamma conversion, color conversion, resolution conversion, sharpening processing, and IP conversion on the input video signal.

  The OSD superimposing unit 20 superimposes the OSD image on the video signal output from the video processing unit 10. The OSD image can be generated not only based on image data such as a bitmap prepared in advance, but also based on a drawing instruction in a straight line, a rectangle, or a pixel unit. The geometric distortion correcting unit 40 performs a deformation process on the video signal output from the OSD superimposing unit 20 so as to correct the geometric distortion generated in the projected image. If the geometric distortion correction unit 40 performs appropriate conversion, distortion of the projected image caused by tilt projection or the like can be suppressed.

  The liquid crystal driving unit 50 is connected to the geometric distortion correcting unit 40, converts the image signal corrected by the geometric distortion correcting unit 40 into a liquid crystal driving signal, and drives the liquid crystal display element 66 of the optical system 60. The optical system 60 includes a lamp 62, an illumination optical system 64, a liquid crystal display element 66, and a projection optical system 68. The light emitted from the lamp 62 passes through the illumination optical system 64, is modulated by the liquid crystal display element 66, and then is projected onto the screen as a projection image through the projection optical system (projection lens) 68. The liquid crystal display element 66 is connected to the liquid crystal driving unit 50 and modulates an incident light beam based on a liquid crystal driving signal from the liquid crystal driving unit 50. Also, the projection optical system 68 can adjust the optical zoom (enlargement and reduction of the projected image), the optical shift (movement of the projection position), and the focus position by moving the lens and unit with a motor. .

  The operation unit 70 includes a button for a user to input an operation and an infrared light receiving unit for receiving infrared light from a remote controller, and converts the input operation into an electrical signal. The types of operation include determination, cancellation, menu call for various settings, up / down / left / right direction instructions, power control, and the like.

  The CPU unit 30 is connected to the video processing unit 10, the OSD superimposing unit 20, the geometric distortion correction unit 40, the operation unit 70, and the projection optical system 68. The CPU unit 30 is a microcomputer (processing unit) that controls the power supply and state of each unit of the liquid crystal projector 100. In addition, it receives user operation input from the operation unit 70 and performs control according to the operation. For example, the OSD superimposing unit 20 is controlled to display a menu screen, the image processing unit 10, the geometric distortion correction unit 40, the projection optical system 68 are controlled, the state and function of each unit, the state acquisition, etc. Or do. Further, in response to the projection image shift instruction received from the operation unit 70, the CPU unit 30 corrects the focus position in conjunction with the shift and sets the projection position in the projection optical system 68.

  FIG. 2 is a flowchart for explaining the operation of correcting the focus position by the projection optical system 68, which is controlled by the CPU unit 30 of the present embodiment. This process is executed by the CPU 30 in accordance with a computer program (control program). Here, it is assumed that the flow shown in FIG. 2 is started every certain time (for example, 1 millisecond).

  When the process is started, in step S <b> 10, the CPU unit 30 determines whether or not shift operation information (including the direction and the shift amount) of the projection image is input to the operation unit 70. If an operation has been input, the process proceeds to step S20. Otherwise, this flow ends.

  In step S <b> 20, the CPU unit 30 acquires the current correction setting from the geometric distortion correction unit 40. If the correction is valid, the process proceeds to step S30. If the correction is invalid, the process proceeds to step S40.

  In step S30, the CPU unit 30 obtains a focus position correction amount based on the shift operation information input from the operation unit 70, and sets the corrected focus position in the projection optical system 68 (performs motor control or the like). .

  In step S <b> 40, the CPU unit 30 sets an optical shift for the projection optical system 68. The setting performed here is performed based on the shift operation information input from the operation unit 70. Then, after the setting of the optical shift for the projection optical system 68 is finished, this flow is finished.

  Hereinafter, the correction performed in step S30 will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a state in which the focus is corrected with respect to FIG. 4 in which the focus is shifted by adjusting the projection position of the projector.

  In FIG. 5, the focus is corrected so that the center of the projection image o ′ after adjusting the projection position and the intersection of the screen S are in focus. That is, the correction performed here refers to the distance z ′ from the projector with respect to the intersection o ″ between the optical axis and the focused surface F ′ after the focus correction, and the projection distance from z to z ′. This means that the focus position is readjusted to follow the change. Assuming that the center of the projected image is inclined to the left by the angle α by adjusting the projection position (that is, the angle formed by the point o, the projector 100, and the point o ′ is α), z ′ is obtained by the following equation [Formula 1]. Can do.

  Here, θ and α are larger than 0 ° and smaller than 45 °. As for θ, the correction amount and angle set in the geometric distortion correction unit 40 correspond (for example, +1 of the set value corresponds to 0.5 °), and can be obtained by acquiring the correction amount. Is possible.

  Note that even if the geometric distortion correction function is a function that designates, for example, the four corner points of the projected image and performs projective transformation of the projected image to that shape, it assumes that the projected image forms a rectangle on the screen. If considered, it is possible to obtain the angle from the information on the positions of the four corners, the angle of view, and the projection position.

  As described above, in this embodiment, even if the projection position is adjusted by the correction in step S30, the focus position is corrected so that the in-focus plane F matches the intersection point of the adjusted projection image center o ′ and the screen S. Is done. For this reason, when the operator adjusts the projection position, it is possible to prevent the focus from being unintentionally shifted.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  In the above-described embodiment, the example in which the center position of the projection image is corrected to be in focus has been described. However, the focus position may be other than the center position of the projection image, and may be corrected so that the focus is set to a specific position set by the operator, or may be the center of the projection image after geometric distortion correction. . Moreover, you may correct | amend so that it may focus on not only the specific position on a screen but the average depth of a projection surface.

  In the above-described embodiment, the flow for adjusting the projection position after focus correction has been described. However, the timing for performing the focus correction may be other than this, and may be performed in parallel with the adjustment of the projection position, or may be performed after the adjustment of the projection position. Moreover, it is good also as a structure which starts correction | amendment operation | movement for the first time when any position on a projection surface stops focusing.

  In the above-described embodiment, the case where the shape of the projection surface is a plane has been described. However, the shape of the projected surface may be other than this, and may be a curved surface, an uneven surface, a refracting surface, or a combination of them. In the above-described embodiment, the case where the state of the projection surface is determined from the correction amount of the geometric distortion correction has been described. However, the state of the projection surface may be determined from other information, or the user may input spatial information and make a determination based on the information.

  In the above-described embodiment, the case where the projection position is adjusted based on the operation input to the operation unit 70 has been described. However, the condition for adjusting the projection position may be other than this, and correction may be performed for a pre-programmed shift operation. Further, in the above-described embodiment, the case where the shift is performed by the projection optical system 68 has been described. However, the shift may be performed by other means, such as movement of the liquid crystal display element 66 itself, movement of a position where an image is drawn on the liquid crystal display element 66 by the liquid crystal driving unit 50, or a combination thereof. good.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

10 video processing unit, 20 OSD superimposing unit, 30 CPU unit, 40 geometric distortion correcting unit,
50 liquid crystal drive unit, 60 optical system, 62 lamp, 64 illumination optical system,
66 liquid crystal display elements, 68 projection optical systems, 100 liquid crystal projectors

Claims (5)

An image projection apparatus that projects a video signal and forms a projection image on a projection surface,
Shift means for shifting the projection position of the projection image;
Focus means for adjusting the focus position of the projected image;
State acquisition means for acquiring the state of the projection surface;
Control means for controlling the focus position by the focus means based on the shift amount and the state acquired by the state acquisition means when a shift is performed by the shift means;
An image projection apparatus comprising: The image projection apparatus according to claim 1, wherein the control unit adjusts a focus position so that a focus at a specific position of the projection image is matched with the projection surface. The image projection apparatus according to claim 2, further comprising a position setting unit for setting the specific position. 4. The image projection apparatus according to claim 1, wherein the control unit controls the focus position to coincide with an average projection depth of the projection image. 5. 5. The apparatus according to claim 1, further comprising a correction unit configured to correct geometric distortion, wherein the state acquisition unit obtains an inclination state of the projection surface based on a correction amount of the correction unit. The image projection apparatus according to item.