JP2014182322A - Projection display device and control method of projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a reduction effect of speckle noise without affecting an image to be displayed on a projection surface.SOLUTION: A projector 1 comprises: a laser light source 11 emitting a laser beam; a display panel 20 modulating the laser beam according to an image signal to emit image light; a projector lens 41 projecting the image light emitted by the display panel 20 onto a screen S (projection surface); projector lens movement means moving the projector lens 41 in a direction intersecting an optical axis; and optical path change means changing an optical path of the image light so as not to change a position of the image displayed on the screen S when the projector lens movement means moves the projector lens 41.

Description

  The present invention relates to a technique for reducing speckle noise.

  Since laser light is light with high coherence, for example, in a projector using a laser light source, speckle noise (also referred to as a speckle pattern) in which bright spots and dark spots are randomly distributed in an image that is enlarged and projected on a projection surface. ) May occur. Speckle noise is generated when light emitted from each point of the projection optical system interferes with an irregular phase relationship, and causes the viewer to flicker. Patent Documents 1 to 3 disclose an invention for reducing speckle noise.

JP 2002-90881 A JP 2009-151221 A JP 2009-198637 A

The invention described in Patent Document 1 moves the optical component so that the optical path difference distribution fluctuates with time. However, since it can be moved only within a range that does not affect the image displayed on the screen, The noise reduction effect may be limited. If the amount of movement of the optical component is increased, a change in the position of the projected image is visually recognized by the observer, and the image is blurred and recognized. In the inventions described in Patent Documents 2 and 3, laser light (image light) is selectively switched to p-polarized light or s-polarized light, but the effect of reducing speckle noise can be obtained only within this switching range.
The present invention has been made in view of the above-described circumstances, and one of its purposes is to improve the speckle noise reduction effect without affecting the image displayed on the projection surface.

To achieve the above object, a projection display device according to the present invention includes a laser light source that emits laser light, a display panel that emits image light by modulating the laser light according to an image signal, When a projection lens that projects image light emitted from the display panel onto a projection surface, a projection lens moving unit that moves the projection lens in a direction that intersects the optical axis, and the projection lens moving unit moves the projection lens And an optical path changing means for changing the optical path of the image light so that the position of the image displayed on the projection surface does not change.
According to the present invention, since the optical path of the image light is changed so as to cancel the change in the position of the image on the projection surface caused by the movement of the projection lens, the image displayed on the projection surface is not affected. The effect of reducing speckle noise can be improved.

In the projection display device according to the present invention, the optical path changing means may move the display panel in a direction intersecting the optical axis.
According to the present invention, speckle noise can be reduced without affecting the image displayed on the projection surface by moving the display panel in a direction intersecting the optical axis of the projection lens.

The projection display device according to the present invention includes a parallel-plate-shaped translucent member provided on the optical path of the image light, and the optical path changing unit changes an incident angle of the image light with respect to the translucent member. As such, the translucent member may be moved.
According to the present invention, speckle noise can be reduced without affecting the image displayed on the projection surface by changing the incident angle of the image light with respect to the translucent member.

In the projection type display device according to the present invention, the incident image light is converted into a specified polarization direction and emitted, and the image is provided on the optical path of the image light emitted by the polarization means. A birefringent member having a different refractive index depending on the polarization direction of the light, and the optical path changing means may switch the polarization direction converted by the polarization means.
According to the present invention, the speckle can be changed without affecting the image displayed on the projection surface by changing the polarization direction of the image light incident on the birefringent member without moving any optical component other than the projection lens. Noise can be reduced.

In the projection display device according to the present invention, the optical path changing means may change the position of an image formed on the display panel in accordance with the image signal.
According to the present invention, speckle noise is reduced without affecting the image displayed on the projection surface by changing the position of the image formed on the display panel without moving any optical component other than the projection lens. Can be made.

In the projection display device according to the present invention, the projection lens may include a plurality of lenses, and the projection lens moving unit may move at least one of the plurality of lenses.
According to the present invention, speckle noise can be reduced without affecting the image displayed on the projection surface by moving only a part of the plurality of lenses constituting the projection lens.

  The present invention can be conceived as a method for controlling a projection display device in addition to a projection display device.

FIG. 2 is a plan view showing the configuration of the projector according to the first embodiment of the invention. FIG. 2 is a block diagram showing a configuration of the projector. Explanatory drawing of the mode of a movement of the optical component in the projector. Explanatory drawing of the relationship between the position of the optical component, and the optical path of image light. FIG. 6 is a plan view showing a configuration of a projector according to a second embodiment of the invention. FIG. 2 is a block diagram showing a configuration of the projector. Explanatory drawing of the mode of a movement of the optical component in the projector. Explanatory drawing of the other example of the optical component in the projector. FIG. 6 is a plan view showing a configuration of a projector according to a third embodiment of the invention. FIG. 2 is a block diagram showing a configuration of the projector. The block diagram which shows the structure of the projector which concerns on 4th Embodiment of this invention. Explanatory drawing of the relationship between the position of the optical component in the projector and the optical path of image light.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 is a plan view showing the configuration of the projector according to the first embodiment of the invention. Here, the projector 1 is a liquid crystal projector, and is a projection display device that projects image light onto a reflective screen S. As illustrated in FIG. 1, the projector 1 includes light source units 10R, 10G, and 10B, display panels 20R, 20G, and 20B, a dichroic prism 30, and a projection unit 40. Regarding the components of the projector 1, the suffix “R” attached to the last symbol corresponds to the red (R) color component, and the suffix “G” corresponds to the green (G) color component. The structure with “B” corresponds to the blue (B) color component. The light source units 10R, 10G, and 10B have the same configuration except for the color of the light source. The display panels 20R, 20G, and 20B have the same configuration except that the colors of images to be formed are different.
In the following description, when it is not necessary to distinguish the components of each color component, the description will be made by omitting the alphabet (R, G or B) at the end of the reference numerals.

  The light source unit 10R is a red light source unit that emits R-color laser light. The light source unit 10G is a green light source unit that emits G-color laser light. The light source unit 10B is a blue light source unit that emits B-color laser light. The light source unit 10 includes a laser light source 11, a diffractive optical element 12, and an angle adjusting optical element 13. Here, the laser light source 11 is a semiconductor laser and emits laser light. The diffractive optical element 12 diffracts the laser light emitted from the laser light source 11. The angle adjusting optical element 13 adjusts the emission angle of the laser light diffracted by the diffractive optical element 12.

The display panel 20 is a transmissive liquid crystal light valve, and is a light modulation device that modulates laser light incident from the light source unit 10 according to an image signal and emits image light. The display panel 20R forms an R color component image and emits R light. The display panel 20G forms an image of a G color component and emits G color light. The display panel 20B forms an image of a B color component and emits B color light. The image light emitted from the display panels 20R, 20G, and 20B enters the dichroic prism 30 from three directions. In the dichroic prism 30, the R and B color image lights are refracted by 90 degrees, while the G color image light travels straight. The dichroic prism 30 combines the image light of each color modulated by the display panels 20R, 20G, and 20B, and emits the combined image light toward the projection unit 40.
As shown by being surrounded by a broken line in FIG. 1, the display panels 20R, 20G, and 20B are formed integrally with the dichroic prism 30 by a so-called POP (Panel On Prism) structure.

  The projection unit 40 includes a projection lens 41 including a plurality of lenses (for example, a convex lens and a concave lens), and the projection lens 41 enlarges and projects the image light synthesized by the dichroic prism 30 on the screen S. However, the shape, size, arrangement interval, number of lenses, telecentricity, magnification and other lens characteristics of the lens included in the projection lens 41 can be set as appropriate according to required characteristics.

FIG. 2 is a block diagram showing the configuration of the projector 1. As shown in FIG. 2, the projector 1 includes a control unit 100, a display control unit 110, a first drive unit 120, and a second drive unit 130 in addition to the configuration described with reference to FIG. 1.
The control unit 100 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM), and controls each unit of the projector 1. For example, the control unit 100 controls the light source units 10R, 10B, and 10G to emit laser light. The display control unit 110 controls the image display on the projector 1. For example, the display control unit 110 performs control to form an image on the display panel 20 in accordance with an image signal input from an interface (not shown). The first driving unit 120 is a driving unit such as an actuator, and moves the projection unit 40 (that is, the projection lens 41) (projection lens moving unit). The second driving unit 130 is a driving unit such as an actuator, and moves the display panel 20 and the dichroic prism 30 integrated by the POP structure (optical path changing unit).

  The first drive unit 120 moves the projection unit 40 under the control unit 100 in order to reduce speckle noise. The second drive unit 130 moves the display panel 20 and the dichroic prism 30 so that the position of the projection image on the screen S caused by the movement of the projection unit 40 does not change under the control unit 100. When the second drive unit 130 moves the display panel 20 and the dichroic prism 30, the optical path of the image light emitted from the display panel 20 is changed with this movement.

FIG. 3 is a diagram for explaining the movement of the projection lens 41, the display panel 20, and the dichroic prism 30 in the projector 1. FIG. 3 shows a state in which the projector 1 that projects image light onto the screen S is viewed obliquely from above. A one-dot chain line shown in FIG. 3 means the optical axis of the projection lens 41.
As indicated by an arrow A1, the control unit 100 controls the first drive unit 120 to reciprocate the projection unit 40 in a direction that intersects the optical axis of the projection lens 41. Here, the control unit 100 moves the projection unit 40 in the vertical direction (that is, the vertical direction). The frequency of this reciprocation is, for example, 10 Hz, but it is preferable to set the frequency so that speckle noise generated on the screen S is not visually recognized by the observer.

  As indicated by an arrow A2, the control unit 100 controls the second driving unit 130 to reciprocate the display panel 20 and the dichroic prism 30 in a direction intersecting the optical axis of the projection lens 41. The control unit 100 moves the display panel 20 and the dichroic prism 30 in the vertical direction at the same frequency as the movement of the projection unit 40 so as to synchronize with the movement of the projection unit 40. Specifically, when the projection unit 40 is moved upward, the control unit 100 moves the display panel 20 and the dichroic prism 30 downward (in the direction of solid arrows of arrows A1 and A2). When the control unit 100 moves the projection unit 40 downward, the control unit 100 moves the display panel 20 and the dichroic prism 30 upward (in the direction of broken arrows indicated by arrows A1 and A2). Regarding the movement amount, the control unit 100 has a size that can cancel out the change in the position of the projection image on the screen S due to the movement of the projection unit 40. The optimum amount of movement is considered to change depending on the distance between the projection unit 40 and the screen S, but may be set in advance in consideration of the distance between the projection unit 40 and the screen S when the projector 1 is used.

  FIG. 4 is a diagram for explaining the relationship between the positions of the display panel 20 and the dichroic prism 30 and the optical path of the image light emitted from the display panel 20. Since the relationship between the position of the dichroic prism 30 and the change of the optical path of the image light is not taken into consideration, illustration and description thereof are omitted. Here, a case where the projection unit 40 is moved upward (arrow A1 direction) and the display panel 20 is moved downward (arrow A2 direction) will be described. In FIG. 4, the projection lens 41 is represented by one convex lens for the sake of simplicity. Each of the squares constituting the display panel 20 corresponds to one pixel of the display panel 20.

As shown in FIG. 4, the image light emitted from the pixel p1 travels along the optical path L1. Specifically, the image light emitted from the pixel p1 enters the projection lens 41, refracts according to the refractive index of the projection lens 41, and reaches the position Ps on the screen S. Next, the case where the projection lens 41 is moved in the direction of the arrow A1 (upward) and the display panel 20 is moved by one pixel in the direction of the arrow A2 (downward) will be described. In this case, the pixel p1 moves to the position of the pixel p2 one pixel below. Here, the image light emitted from the pixel p2 travels along the optical path L2. Specifically, the image light is incident on the projection lens 41, refracted according to the refractive index of the projection lens 41, and reaches the position Ps on the screen S. The movement amounts of the projection unit 40 and the display panel 20 are set so that the optical paths L1 and L2 both reach the position Ps on the screen S. In this way, the control unit 100 moves the display panel 20 and the projection unit 40 (that is, the projection lens 41) in a direction that intersects the optical axis of the projection lens 41, and in the opposite direction, thereby moving the screen S. The position of the upper projected image is not changed.
When the movement amount of the projection unit 40 is further increased, the change in the position of the projected image due to the movement of the projection unit 40 can be offset by increasing the movement amount of the display panel 20 by that amount. Here, a case has been described in which the control unit 100 moves the projection unit 40 upward and moves the display panel 20 downward. However, the control unit 100 moves the projection unit 40 downward and moves the display panel 20 upward. The same can be said for the case of moving to.

  In the first embodiment described above, when the projector 1 moves the projection unit 40 to reduce speckle noise, the projector 1 moves the display panel 20 in synchronization with this movement to change the optical path of the image light. As a result, in the projector 1, the position of the projected image on the screen S can be prevented from changing due to the movement of the projection unit 40. As described above, even when the movement amount of the projection unit 40 is increased, the change in the position of the projection image can be offset by the movement of the display panel 20, so that the projector 1 affects the projection image. The effect of reducing speckle noise can be improved without giving an effect.

Second Embodiment
Next, a second embodiment of the present invention will be described.
Also in this embodiment, the projector 1 moves the projection unit 40 to reduce speckle noise, and moves the optical component in synchronization with this movement, so that the position of the projection image does not change. The difference from the configuration of the first embodiment described above is that the projector 1 of this embodiment moves optical components other than the display panel 20. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 5 is a plan view showing the configuration of the projector 1 according to the second embodiment. The configuration of the portion not shown in FIG. 5 is the same as that of the first embodiment described above. However, the display panel 20 and the dichroic prism 30 may not be integrated by the POP structure in this embodiment.
As shown in FIG. 5, in the projector 1 of this embodiment, a translucent member 50 is provided between the dichroic prism 30 and the projection unit 40 on the optical path of the image light emitted from the dichroic prism 30. . The translucent member 50 is a parallel plate-shaped translucent member formed of a material having translucency such as glass. 5 represents the optical axis of the projection lens 41. In the state shown in FIG. 5, the incident surface and the exit surface of the image light of the translucent member 50 are orthogonal to the optical axis of the projection lens 41.

  FIG. 6 is a block diagram showing the configuration of the projector 1. As shown in FIG. 6, in the projector 1 of this embodiment, the second driving unit 130 moves the light transmissive member 50. The second drive unit 130 is, for example, an actuator, and moves the translucent member 50 so as to change the optical path of the image light emitted from the dichroic prism 30 (optical path changing unit). Here, the control unit 100 moves the translucent member 50 so that the position of the projection image on the screen S does not change due to the movement of the projection unit 40. The description of other components in the projector 1 is omitted.

  FIG. 7 is a diagram illustrating the relationship between the posture of the translucent member 50 and the optical path of the image light. FIG. 7 is a plan view showing a state when the translucent member 50 is viewed from the same direction (upward direction) as FIG. In the state shown in FIG. 7A, the optical axis of the projection lens 41 and the incident surface of the translucent member 50 are orthogonal to each other. For this reason, the image light incident on the translucent member 50 at an incident angle of approximately 0 degrees goes straight as it is and travels on the optical path L3. FIG. 7B is a diagram illustrating a state in which the second driving unit 130 is rotated by a predetermined angle in the direction of the arrow A3 with the axis passing through the center of gravity of the translucent member 50 as a rotation axis. In the state shown in FIG. 7B, the incident angle of the image light with respect to the translucent member 50 becomes larger than in the state shown in FIG. Therefore, the image light is refracted according to the refractive index of the translucent member 50 and travels along the optical path L4. For this reason, when the translucent member 50 is in the state shown in FIG. 7A (optical path L3) and in the state shown in FIG. 7B (optical path L4), on the rear side of the translucent member 50, The image light has an optical path shifted by a distance d1 in the left-right direction (horizontal direction).

  Therefore, in synchronization with the movement of the projection unit 40, the control unit 100 moves the translucent member 50 to change the optical path of the image light so as not to change the position of the projection image. Specifically, the control unit 100 alternates the posture of the translucent member 50 between the state shown in FIG. 7A and the state shown in FIG. 7B at the same cycle as the reciprocating movement of the projection unit 40. Switch. When the control unit 100 moves the projection unit 40 in the right direction in the figure, the incident angle with respect to the translucent member 50 is reduced so that the image light travels in the optical path L3, and the projection unit 40 is moved in the left direction in the figure. In such a case, the incident angle with respect to the translucent member 50 is increased so that the image light travels along the optical path L4. Here, the movement conditions such as the material, the angle, and the rotation angle of the translucent member 50 may be set according to the movement direction and the movement amount of the projection unit 40 so that the position of the projection image does not change.

  According to the second embodiment described above, the projector 1 moves the light transmitting member 50 in synchronization with the movement of the projection unit 40 when the projection unit 40 is moved to reduce speckle noise. It is possible to prevent the position of the projected image from changing. In general, since the light transmissive member 50 is lighter than the display panel 20 and the dichroic prism 30, according to the projector 1 of this embodiment, it is possible to suppress the generation of noise due to the movement of the optical components.

  By the way, the structure which moves a parallel plate-shaped translucent member is not limited to the structure demonstrated using FIG. As shown in FIG. 8, the translucent member may be a disc-shaped translucent member 50a, and the first drive unit 120 may rotate the translucent member 50a. 8A and 8C show a state in which the second driving unit 130 and the translucent member 50a are viewed in the same direction as FIG. FIG. 8B illustrates a state in which the second driving unit 130 and the translucent member 50a are viewed obliquely from below. In this example, the 2nd drive part 130 is a drive means for giving rotational force to the translucent member 50a, for example, is a motor. The motor shaft of the second drive unit 130 and the center of the circular translucent member 50a are connected so that the translucent member 50a can rotate. Here, the axial direction of the motor shaft and the surface of the translucent member 50a are not orthogonal to each other, and the translucent member 50a is connected to the motor shaft in a posture inclined with respect to the optical axis.

In the state shown in FIG. 8A, after the image light is incident on the light transmitting member 50a, it is refracted in the left direction in the figure and is emitted from the light transmitting member 50a. When the light transmitting member 50a is rotated 180 degrees in the direction of arrow A4 from the state of FIG. 8A, the light transmitting member 50a is in the state shown in FIG. In the state shown in FIG. 8C, after the image light is incident on the light transmitting member 50a, the image light is refracted in the right direction in the figure and is emitted from the light transmitting member 50a. As can be seen from FIG. 8A and FIG. 8C, the incident angle of the image light changes according to the attitude of the translucent member 50a. Thereby, in the period when the translucent member 50a rotates, the optical path of the image light is changed as in the case of the configuration shown in FIG. The movement conditions such as the material and rotation speed (angular velocity) of the translucent member 50a may be set in advance so that the position of the projection image does not change due to the movement of the projection unit 40.
According to the second embodiment described above, the projector 1 only needs to rotate the translucent member 50a by the driving force of the motor, which is preferable in terms of simplifying the configuration of the second driving unit 130.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
Also in this embodiment, the projector 1 moves the projection unit 40 to reduce speckle noise, and changes the optical path of the image light so that the position of the projection image does not change. The difference from the first and second embodiments described above is that the projector 1 of this embodiment changes the optical path of the image light without moving the optical component. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 9 is a plan view showing the configuration of the projector 1 according to the third embodiment. The configuration of the portion not shown in FIG. 9 is the same as that of the first embodiment described above. However, the display panel 20 and the dichroic prism 30 may not be integrated by the POP structure in this embodiment.
As shown in FIG. 9, in the projector 1 of this embodiment, the polarizing element 60 and the birefringent member 70 are provided between the display panel 20 and the dichroic prism 30. The polarizing element 60 and the birefringent member 70 are respectively positioned on the optical path of the image light emitted from the display panel 20. The polarizing element 60 is, for example, a liquid crystal panel or a wave plate using a liquid crystal element, and is a polarizing means provided so that both surfaces of the translucent member 50 are orthogonal to the optical axis. Here, the polarizing element 60 converts the polarization direction of the image light incident from the display panel 20 into one of p-polarized light and s-polarized light and emits it. Whether the polarizing element 60 converts to p-polarized light or s-polarized light can be specified by voltage application from the outside.

  The birefringent member 70 is formed in, for example, a parallel plate shape using quartz, and image light whose polarization direction is changed by the polarizing element 60 is incident thereon. The birefringent member 70 is configured such that the optical axis is parallel to the linearly polarized light of the incident image light. Further, the birefringent member 70 is disposed in a state inclined with respect to the optical axis of the projection lens 41. Under this configuration, the birefringent member 70 functions as a prism having a different refractive index depending on the polarization direction of the incident image light. That is, the birefringent member 70 emits image light refracted at different refractive indexes when p-polarized image light is incident and when s-polarized image light is incident.

  FIG. 10 is a block diagram illustrating a configuration of the projector 1. As shown in FIG. 10, the projector 1 of this embodiment is different from the configuration of the first embodiment described above in that a voltage control unit 140 is provided instead of the second drive unit 130. The voltage control unit 140 controls the voltage applied to the polarizing element 60 and designates the polarization direction to be converted into the polarizing element 60. The voltage control unit 140 controls the voltage applied to the polarizing element 60 so that the position of the image on the screen S does not change due to the movement of the projection unit 40 under the control unit 100, and the optical path of the image light Is changed (optical path changing means). The description of other components in the projector 1 is omitted.

  When the voltage control unit 140 converts the polarizing element 60 into p-polarized light, the image light incident on the birefringent member 70 becomes an ordinary ray, so that the image light travels in an optical path L5 having a small refractive index and almost straight. . Next, when the voltage control unit 140 converts the polarizing element 60 to s-polarized light, since the polarization direction of the s-polarized light is orthogonal to the optical axis of the birefringent member 70, the image light incident on the birefringent member 70 is abnormal. The light beam is refracted with a large refractive index, and the image light travels in the optical path L6. For this reason, as shown in FIG. 9, in the case where the polarizing element 60 converts to s-polarized light and to convert to p-polarized light, the rear side of the birefringent member 70 is shifted by a distance d2 in the vertical direction in the figure. It becomes an optical path.

  Therefore, the control unit 100 switches the polarization direction to be converted to the polarization element 60 in synchronization with the movement of the projection unit 40 and changes the optical path of the image light, so that the position of the projection image is moved by the movement of the projection unit 40. Do not change. This switching cycle may be the same as the cycle of the reciprocating movement of the projection unit 40.

  According to the third embodiment described above, the projector 1 can move the projection unit 40 to reduce speckle noise and prevent the position of the projection image from changing. Furthermore, in this projector 1, since the optical path of the image light is changed without moving any optical component other than the projection unit 40, it is also preferable in terms of suppressing noise generated by the movement of the optical component such as a driving sound of a motor.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described.
Also in this embodiment, the projector 1 moves the projection unit 40 to reduce speckle noise and changes the optical path of the image light so that the position of the projection image does not change. The difference from the first to third embodiments described above is that the projector 1 of this embodiment changes the optical path of the image light by changing the position of the image formed on the display panel 20. The configuration of the projector 1 of this embodiment may be the configuration shown in FIG. However, the display panel 20 and the dichroic prism 30 may not be integrated by the POP structure. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 11 is a block diagram illustrating a configuration of the projector 1. As shown in FIG. 11, the projector 1 of each embodiment is different from the configuration of the first embodiment described above in that the projector 1 does not have to have a configuration corresponding to the second drive unit 130. In this embodiment, the display control unit 110 changes the position of the image to be written on the display panel 20 so as to cancel the change in the position of the projection image due to the movement of the projection unit 40 (optical path changing unit). The description of other components in the projector 1 is omitted.

FIG. 12 is a diagram for explaining the relationship between the pixel position of the display panel 20 and the optical path of the image light emitted from the display panel 20. In FIG. 12, the projection lens 41 is represented by a single convex lens in order to simplify the illustration. Each of the squares constituting the display panel 20 corresponds to one pixel of the display panel 20.
In the projector 1 according to the first embodiment described above, the optical path of the image light is changed by moving the display panel 20. It is the projector 1 of this embodiment that realizes this optical path change by changing the position of the image written on the display panel 20.

  As shown in FIG. 12, the image light emitted from the pixel p1 travels along the optical path L7. Specifically, the image light is incident on the projection lens 41, refracted according to the refractive index of the projection lens 41, and reaches the position Ps on the screen S. Next, consider a case where the projection unit 40 (projection lens 41) is moved in the direction of arrow A5 (upward). In this case, the image light emitted from the pixel p2 travels along the optical path L8. Specifically, the image light is incident on the projection lens 41, refracted according to the refractive index of the projection lens 41, and reaches the position Ps on the screen S. Therefore, the display control unit 110 writes the image signal to be written in the pixel p1 to the pixel p2 that is moved by one pixel in the direction of arrow A6 (downward), and changes the optical path of the image light. The position of the projected image due to movement can be prevented from changing. Here, the control unit 100 reciprocates the position of the image formed on the display panel 20 at the same frequency as the reciprocation of the projection unit 40 so as to synchronize with the movement of the projection unit 40.

  Even when the movement amount of the projection unit 40 is further increased, the display control unit 110 may increase the number of pixels that change the position of the image formed on the display panel 20 by that amount. Although the case where the projection unit 40 is moved upward has been described here, the position of the image to be written on the display panel 20 is the opposite regardless of which direction the projection unit 40 is moved up, down, left, or right. By changing to the direction, it is possible to prevent the position of the projected image from changing.

  According to the fourth embodiment described above, the projector 1 can move the projection unit 40 to reduce speckle noise and prevent the position of the projection image from changing. Further, in the projector 1, it is not necessary to move optical components other than the projection unit 40, which is preferable in terms of suppressing noise generated by the movement of the optical components.

<Modification>
The present invention can be implemented in a form different from the above-described embodiment. Further, the following modifications may be combined as appropriate.
In each embodiment mentioned above, the projector 1 moved the whole projection part 40, ie, the whole projection part 40 was moved. Instead of this, the projector 1 may move only the projection lens 41 without moving the housing or the like of the projection unit 40. In this case, when the projection lens 41 includes a plurality of lenses, the projector 1 may move at least one of the plurality of lenses of the projection lens 41.

  Further, when the projector 1 includes an optical component (lens) provided between the projection lens 41 and the screen S, the position of the projection image can also be obtained by moving the optical component in synchronization with the projection lens 41. The change of can be suppressed. That is, the projector 1 may move any optical component provided between the display panel 20 and the screen S as long as the optical path of the image light can be changed.

In the first embodiment described above, the projector 1 moves the display panel 20 and the dichroic prism 30 integrated by the POP structure. When the projector 1 can move the display panel 20 independently of the dichroic prism 30, the display panel 20 may be moved without moving the dichroic prism 30.
In the third embodiment described above, the polarizing element 60 and the birefringent member 70 are provided between the display panel 20 and the dichroic prism 30, but for example, between the dichroic prism 30 and the projection unit 40. It may be provided in the position.

  The projector 1 is not limited to one having a plurality of light valves corresponding to each color component. The projector 1 may have a single light valve. In this case, a color corresponding to each pixel is set using an optical filter or the like. The light valve is not limited to one using a transmissive liquid crystal panel, and may be one using a reflective liquid crystal panel. Further, the projector 1 is not limited to a liquid crystal projector, and may be a projector using DMD (Digital Mirror Device), LCOS (Liquid Crystal On Silicon), or the like.

DESCRIPTION OF SYMBOLS 1 ... Projector 10, 10R, 10G, 10B ... Light source part, 11, 11R, 11G, 11B ... Laser light source, 20, 20R, 20G, 20B ... Display panel, 30 ... Dichroic prism, 40 ... Projection part, 41 ... Projection Lens, 50, 50a ... Translucent member, 60 ... Polarizing element, 70 ... Birefringent member, 100 ... Control unit, 110 ... Display control unit, 120 ... First drive unit, 130 ... Second drive unit, 140 ... Voltage control Department.

Claims (7)

A laser light source for emitting laser light;
A display panel that emits image light by modulating the laser light according to an image signal;
A projection lens that projects image light emitted from the display panel onto a projection surface;
A projection lens moving means for moving the projection lens in a direction intersecting the optical axis;
A projection type display device comprising: an optical path changing unit that changes an optical path of the image light so that a position of an image displayed on the projection surface does not change when the projection lens moving unit moves the projection lens. . The optical path changing means is
The projection display device according to claim 1, wherein the display panel is moved in a direction intersecting the optical axis. A parallel plate-shaped translucent member provided on the optical path of the image light;
The optical path changing means is
The projection display device according to claim 1, wherein the light transmissive member is moved so as to change an incident angle of the image light with respect to the light transmissive member. Polarization means for converting the incident image light into a designated polarization direction and emitting the light; and
A birefringent member provided on the optical path of the image light emitted by the polarizing means, and having a different refractive index depending on the polarization direction of the image light,
The optical path changing means is
The projection display device according to claim 1, wherein the polarization direction converted by the polarization unit is switched. The optical path changing means is
The projection display device according to claim 1, wherein a position of an image formed on the display panel is changed according to the image signal. The projection lens includes a plurality of lenses,
The projection lens moving means includes
The projection type display device according to claim 1, wherein at least one of the plurality of lenses is moved. A laser light source for emitting laser light;
A display panel that emits image light by modulating the laser light according to an image signal;
And a projection lens for projecting image light emitted from the display panel onto a projection surface.
Moving the projection lens in a direction intersecting the optical axis;
A method for controlling a projection display apparatus, wherein the optical path of the image light is changed so that the position of an image displayed on the projection surface does not change when the projection lens is moved.

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