JP2021021825A - Image projection device - Google Patents

Abstract

To provide an image projection device that does not limit the shift range of a projector lens more than necessary while ensuring the image quality.SOLUTION: An image projection device (10) includes: lens shift means (109) that shifts a projector lens (201) with respect to the optical axis; derivation means (102) that derives an image display area out of the image forming area of an image display element (104); acquisition means (1071) that acquires the effective image display area of the projector lens; and control means (1072) to control the lens shift means based on the image display area and the effective image display area.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image projection device that controls the shift of a projection lens.

In Patent Document 1, the shift range of the projection lens is limited by the panel size and the effective image display area of the projection lens, and distortion, chromatic aberration, image loss, etc. that occur when image light passes through an optical system such as a projection lens An image projection device that suppresses deterioration of the image quality of the lens is disclosed.

Japanese Patent No. 5744566

However, in the image projection device disclosed in Patent Document 1, the actual display image may not match the panel size, so that the shift range of the projection lens may be limited more than necessary.

Therefore, an object of the present invention is to provide an image projection device that does not unnecessarily limit the shift range of the projection lens while suppressing deterioration of image quality.

The image projection device as one aspect of the present invention includes a lens shifting means for shifting the projection lens with respect to the optical axis, a derivation means for deriving an image display region in the image forming region of the image display element, and the projection lens. It has an acquisition means for acquiring an effective image display area, and a control means for controlling the lens shift means based on the image display area and the effective image display area.

Other objects and features of the present invention will be described in the following examples.

According to the present invention, it is possible to provide an image projection device that does not unnecessarily limit the shift range of the projection lens while suppressing deterioration of image quality.

It is a block diagram of the image projection apparatus in Example 1. It is a schematic diagram which shows the relationship between the effective image display area and the image display area in Example 1. FIG. It is a flowchart which shows the acquisition method of the image display area and the effective image display area in Example 1. FIG. It is a flowchart which shows the control method of the lens shift in Example 1. FIG. It is a block diagram of the image projection apparatus in Example 2. It is a flowchart which shows the control method of the lens shift in Example 2. FIG.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

First, the image projection device (projector) according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of the image projection device 10 in this embodiment. The image projection device 10 includes a main body 100 and a lens unit 200 that can be attached to and detached from the main body 100. In this embodiment, the image projection device 10 is an interchangeable lens type projector, but the present invention is not limited thereto.

The image signal input unit 101 includes an interface connector for image signal input, and an image signal is input from an external device such as a PC. The image signal input to the image signal input unit 101 is output to the image signal processing unit 102. The image signal processing unit 102 performs various image signal processing such as keystone correction, aspect ratio conversion, scaling, brightness correction, contrast correction, and color correction. The image signal processed by the image signal processing unit 102 is output to the liquid crystal panel driving unit 103. Further, the image signal processing unit 102 functions as a derivation means for deriving the image display area displayed on the liquid crystal panel (image display element) 104, and provides a black band area for adjusting the aspect ratio and a black display area generated during keystone correction. Exclude the net image display area. The image display area derived by the image signal processing unit 102 is output to the MPU 107.

The liquid crystal panel driving unit 103 drives the liquid crystal panel 104 based on the input image signal. The liquid crystal panel 104 may be either a transmissive liquid crystal panel or a reflective liquid crystal panel. Further, an image display element such as a Digital Mirror Device (DMD) other than the liquid crystal panel may be used.

The light emitted from the light source 105 is photomodulated by the liquid crystal panel 104 and projected onto a projected surface such as a screen by the projection lens 201 of the lens unit 200. The MPU 107 outputs a light source control command to the light source driving unit 108. The light source driving unit 108 drives the light source such as turning on / off the light source 105 and dimming the light source 105 based on the light source control command from the MPU 107.

The lens unit 200 has an effective image display area storage unit (storage means) 202. The effective image display area storage unit 202 stores the effective image display area. The MPU 107 has an acquisition unit 1071 for acquiring an effective image display area, and acquires an effective image display area from the effective image display area storage unit 202. In this embodiment, the effective image display area storage unit 202 is provided in the lens unit 200. For example, in the case of an image projection device having a fixed lens type instead of an interchangeable lens type, the effective image display area also has a fixed value. Therefore, it may be provided in the main body 100. Further, the lens unit 200 may store information (lens information) that can identify the lens unit such as an ID, and may store an effective image display area corresponding to the identification information in the main body 100.

The effective image display area (image circle) is an area that is light-modulated by the liquid crystal panel 104 and allows the image light (reflected light or transmitted light) to pass through the projection lens 201 without being eclipsed. The light that has passed through the effective image display area forms a projected image with a guaranteed quality. The effective image display area corresponds to (or is similar to) the image circle of the projection lens 201, and its shape can project (display) a projection image (projection image) having an evaluation value higher than a predetermined evaluation value. Area (size, coordinates). Here, the predetermined evaluation value is a value obtained by evaluating, for example, distortion of the projected image, chromatic aberration, chipping of the image, brightness of the projected image, and the like. When the image quality of the projected image is high when the evaluation value is high, and the image quality of the projected image is low when the evaluation value is low, it is the minimum acceptable evaluation value.

The lens shift mechanism (lens shift means) 109 moves the projection position by moving (shifting) the lens unit 200 (that is, the projection lens 201) in the direction perpendicular to the optical axis. The shift direction is not limited to the direction perpendicular to the optical axis, and may be an oblique direction as long as it has a component perpendicular to the optical axis.

The lens shift mechanism 109 includes a lens shift drive unit 110 and a lens shift amount detection unit 111. The lens shift drive unit 110 includes an actuator such as a motor for shifting the lens unit 200 in directions orthogonal to its optical axis (vertical direction and horizontal direction). In this embodiment, a motor (DC motor, stepping motor, vibration type motor, etc.) is used as the actuator, but the actuator is not limited thereto. The lens shift drive unit 110 is controlled by a command from the MPU 107. The lens shift amount detecting unit 111 functions as a center position acquisition means, and acquires the current center position by detecting the movement amount of the lens unit 200. Here, the center position is the center position of the liquid crystal panel 104 (image display area) with respect to the effective image display area (image circle). When the lens unit 200 is not moved, the center position of the effective image display area corresponds to the center position of the liquid crystal panel 104. The center position acquired by the lens shift amount detection unit 111 is output to the MPU 107. The MPU 107 controls the lens shift mechanism 109 based on the center position.

The MPU 107 has a control means 1072 and controls the shift of the projection lens 201 by outputting a drive signal to the lens shift drive unit 110. As will be described later, the control means 1072 of this embodiment controls the lens shift mechanism 109 based on the image display area (image forming area on the light modulation element) and the effective image display area. The operation unit 113 includes switches, dials, buttons, a remote control light receiving unit, and the like (not shown) that accept various operations including a lens shift operation from the user. The operation unit 113 functions as an input means capable of inputting the direction (shift direction) to be shifted by the lens shift mechanism 109 and the shift amount by the user. As a method of inputting the shift amount, for example, a method such as a time when the direction button of the remote controller is pressed (the shift is continued while being pressed), a method of transmitting the shift amount by a user command from a PC (not shown) can be used. It is not limited to these. The control means 1072 controls the lens shift mechanism 109 based on the shift direction and the shift amount.

Next, the relationship between the effective image display area 301 and the image display area 304 in this embodiment will be described with reference to FIG. Here, the effective image display area is an area corresponding to an image circle. The image display area is an image forming area of the light modulation element (that is, the entire area of the liquid crystal panel 104), and the image display area is an area for actually displaying an image on the liquid crystal panel 104. 2 (a) to 2 (c) are schematic views showing the relationship between the effective image display area 301 and the image display area 304. The planes of FIGS. 2A to 2C are planes perpendicular to the optical axis at arbitrary positions on the optical axis of the projection lens 201. This position is, but is not limited to, the position of the injection surface of the projection lens 201 in this embodiment.

FIG. 2A shows a case where the image forming region (entire region) of the light modulation element (liquid crystal panel 104) and the image display region 304 coincide with each other. FIG. 2B shows a case where black display areas (black band areas) 305 exist on the left and right sides of the image forming region of the light modulation element. As an example, when the aspect ratio of the image forming region on the optical modulation element is 16: 9 and the aspect ratio of the input image is 4: 3, the aspect ratio of the input image is 4: 3 by adding black band areas on the left and right. Is maintained and displayed.

FIG. 2C shows the image display area 304 when the keystone correction is performed. The liquid crystal panel region 302 at 0% shift shown by the solid line is a region in which the center of the liquid crystal panel 104 coincides with the optical axis of the projection lens 201 and the light from the liquid crystal panel 104 passes through. The shifted liquid crystal panel region 303 shown by the dotted line is a region through which the light from the shifted liquid crystal panel 104 passes. The shift of the projection lens 201 (lens shift) can be realized by changing the positional relationship between the liquid crystal panel 104 and the projection lens 201 (lens unit 200).

In FIGS. 2B and 2C, the image display area 304 represents a net image display area excluding the black band area for adjusting the aspect ratio and the black display area 305 generated during keystone correction. The black display area 305 represents a black band area for adjusting the aspect ratio and a black display area generated during keystone correction.

If a part of the image display area 304 after shifting goes out of the effective image display area (effective image circle) 301, the projected image is not projected correctly, and distortion, chromatic aberration, image chipping, etc. beyond the permissible level occur. Therefore, it is necessary to move the image display area 304 within the effective image display area. On the other hand, even if a part of the black display area 305 after the shift goes out of the effective image display area 301, black is displayed, so that it is unlikely to be a problem in actual use. That is, the shift movement amount can be increased accordingly. Although the effective image display area 301 of this embodiment is an ellipse, it may have another shape such as a circle or a polygon.

Next, a method of acquiring the image display area and the effective image display area in this embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a method of acquiring an image display area and an effective image display area. Each step of FIG. 3 is mainly executed by the image signal processing unit 102 or the MPU 107.

First, in step S101, the MPU 107 determines whether or not the aspect ratio setting change or the keystone correction change (geometric correction change) is executed by operating the operation unit 113 by the user. When the aspect ratio setting change or the keystone correction change is executed, the process proceeds to step S102. On the other hand, if neither the aspect ratio setting change nor the keystone correction change is executed, the process proceeds to step S103. In step S102, the image signal processing unit 102 derives a net image display area excluding the black band area for adjusting the aspect ratio and the black display area generated during keystone correction. Subsequently, in step S103, the MPU 107 determines whether or not the lens unit 200 (projection lens 201) has been replaced by the user. When the lens unit 200 is replaced, the process proceeds to step S104. On the other hand, if the lens unit 200 has not been replaced, this flow ends. In step S104, the MPU 107 acquires the effective image display area from the effective image display area storage unit 202, and ends this flow.

As described above, in this embodiment, the operation unit (setting means) 113 can set the aspect ratio of the image displayed on the image display element by the user. Then, the image signal processing unit 102 derives an image display area based on the aspect ratio. Further, in this embodiment, the image signal processing unit (correction means) 102 performs geometric correction (keystone correction) of the image by image processing. Then, the image signal processing unit (deriving means) 102 derives the image display area based on the geometrically corrected image.

Next, the lens shift control method in this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a lens shift control method. Each step of FIG. 4 is mainly performed by the MPU 107 or the lens shift mechanism 109.

First, in step S201, when the user performs a lens shift operation by the operation unit 113, the MPU 107 acquires the direction to be shifted (shift direction) and the shift amount from the operation unit 113. The MPU 107 of this embodiment detects the direction in which the liquid crystal panel area 302 in the effective image display area is to be moved by shifting with the center of the liquid crystal panel area 302 (origin in FIG. 2) as a reference position at 0% shift. However, the reference position need only be associated with the liquid crystal panel area 302, and is not necessarily limited to the center position.

Subsequently, in step S202, the MPU 107 derives a target shift position based on the shift direction and shift amount acquired in step S201. Then, the MPU 107 determines whether or not the entire area of the image display area 304 is inside (within the range) of the effective image display area 301 based on the acquired shift direction and shift amount (that is, the target shift position). When the entire area of the image display area 304 is inside the effective image display area 301, the process proceeds to step S204. On the other hand, if at least a part of the image display area 304 is not inside the effective image display area 301, the process proceeds to step S203.

In step S203, the MPU 107 determines whether or not the acquired shift amount can be reduced. Step S203 is particularly effective when the shift amount is directly input by a user command. That is, the MPU 107 determines whether or not the entire area of the image display area 304 after the shift falls within the range of the effective image display area 301 based on the shift amount smaller than the shift amount input by the user via the operation unit 113. To judge. If the MPU 107 determines that the entire area of the image display area 304 after shifting falls within the range of the effective image display area 301 if the shift amount is smaller than the shift amount input to the operation unit 113, the process proceeds to step S204. To do. On the other hand, if it is determined that at least a part of the image display area 304 after the shift does not fall within the range of the effective image display area 301, the lens shift cannot be performed even with the shift amount. Therefore, the MPU 107 ends this flow without performing a lens shift.

In step S204, the MPU 107 controls the lens shift mechanism 109, shifts the lens unit 200 to a position where the entire area of the image display area 304 does not go out of the range of the effective image display area 301, and ends this flow. When the MPU 107 shifts from step S204 to step S205, the MPU 107 controls the lens shift mechanism 109 based on a shift amount smaller than the shift amount input via the operation unit 113.

In this embodiment, whether or not the center of the liquid crystal panel area (image display area) approaches the center of the effective image display area 301 by performing the lens shift to the target shift position between steps S201 and S202. You may insert a step to determine. Further, by shifting the lens unit 200, a step of determining whether or not shift drive is possible may be inserted. When passing through the effective image display area (center of the image passing area) is in a direction approaching the center of the effective image display area 301, the process proceeds to step S204. On the other hand, when the center of the image passing region is away from the center of the effective image display area 301, the process proceeds to step S202.

Next, the image projection apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the image projection device 10a in this embodiment. The image projection device 10a of the present embodiment is different from the image projection device 10 of the first embodiment in that the main body 100a having the MPU 107a is provided instead of the MPU 107. The MPU 107a has a switching means 1073 in addition to the acquisition means 1071 and the control means 1072. In this embodiment, the same reference numerals are given to the same configurations as those in the first embodiment, and the description thereof will be omitted.

The switching means 1073 of the MPU 107a switches the control of the lens shift mechanism 109. Specifically, the switching means 1073 controls the lens shift mechanism 109 so that the entire area of the image display area after shifting falls within the range of the effective image display area, or controls the lens shift mechanism 109 regardless of the control. Switch whether to do it. That is, the switching means 1073 switches between the first control and the second control. The first control is a control that controls the lens shift mechanism 109 so that the entire image display area falls within the range of the effective image display area. The second control is a control that controls the lens shift mechanism 109 without considering whether or not the entire image display area falls within the range of the effective image display area. The switching by the switching means 1073 is changed according to the input from the operation unit 113, and the user can switch the control by operating the operation unit 113.

Next, the lens shift control method in this embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing a lens shift control method. Each step of FIG. 6 is mainly performed by the MPU 107a or the lens shift mechanism 109. Note that FIG. 6 is different from FIG. 4 described in the first embodiment in that step S301 is added. Since the other steps in FIG. 6 are the same as those in FIG. 4, their description will be omitted.

First, in step S301, the MPU 107a (switching means 1073) determines whether or not the effective image area is set to be ignored. The setting for ignoring the effective image area is a setting for controlling the lens shift mechanism 109 regardless of whether or not the entire area of the image display area after shifting falls within the range of the effective image display area. On the other hand, the setting that does not ignore the effective image area is a setting that controls the lens shift mechanism 109 so that the entire area of the image display area after shifting is within the range of the effective image display area. In the case of setting to ignore the effective image area, the process proceeds to step S204. On the other hand, if the setting does not ignore the effective image area, the process proceeds to step S201.

According to each embodiment, it is possible to provide an image projection device that does not unnecessarily limit the shift range of the projection lens while suppressing deterioration of image quality.

Although preferable examples of the present invention have been described above, the present invention is not limited to these examples, and various modifications and modifications can be made within the scope of the gist thereof.

10 Image projection device 102 Image signal processing unit (deriving means)
109 Lens shift mechanism (lens shift means)
200 Lens unit 1071 Acquisition means 1072 Control means

Claims (10)

A lens shifting means that shifts the projection lens with respect to the optical axis,
Derivation means for deriving the image display area in the image forming area of the image display element,
An acquisition means for acquiring an effective image display area of the projection lens, and
An image projection device comprising: a control means for controlling the lens shift means based on the image display area and the effective image display area. Further having an input means capable of inputting the shift direction and shift amount of the projection lens by the user.
The image projection device according to claim 1, wherein the control means controls the lens shift means based on the shift direction and the shift amount. When a part of the image display area does not fit within the range of the effective image display area, the control means sets the input means so that the entire image display area falls within the range of the effective image display area. The image projection apparatus according to claim 2, wherein the lens shift means is controlled based on a shift amount smaller than the shift amount input via the screen. The lens shift means has a center position acquisition means for acquiring the center position of the image display area with respect to the effective image display area.
The image projection device according to any one of claims 1 to 3, wherein the control means controls the lens shift means based on the center position. The control means according to any one of claims 1 to 4, wherein the control means controls the lens shift means so that the entire image display area falls within the range of the effective image display area. Image projection device. Further having a setting means capable of setting the aspect ratio of the image displayed on the image display element by the user.
The image projection device according to any one of claims 1 to 5, wherein the derivation means derives the image display area based on the aspect ratio. It also has a correction means that corrects the geometry of the image by image processing.
The image projection device according to any one of claims 1 to 6, wherein the derivation means derives the image display region based on the geometrically corrected image. The image projection device according to any one of claims 1 to 7, wherein the acquisition means acquires the effective image display area of the projection lens from the storage means. The image projection apparatus according to any one of claims 1 to 8, wherein the effective image display area corresponds to an image circle of the projection lens. Further having a switching means for switching the control of the lens shifting means,
The switching means includes a first control for controlling the lens shift means so that all of the image display area falls within the range of the effective image display area, and all of the image display area of the effective image display area. The image projection apparatus according to any one of claims 1 to 9, wherein the second control for controlling the lens shift means is switched without considering whether or not the lens shift means is within the range.