Patent Description:
In general, the image projected by a projector is a landscape image that has a horizontal width greater than a vertical height. However, for some applications (for example, elevator door projection), a portrait image with a vertical height greater than the horizontal width may also be required. One conventional technique is to set the part, which corresponds to the predetermined projected image region, in the effective region of the digital micro-mirror device (DMD) to the on-state and set the other parts, which correspond to the non-predetermined projected image region, in the effective region to the off-state. For example, when the effective region of the digital micro-mirror device is all set to the on-state, the projector can project a landscape image. When the projector is applied to elevator door projection, the part, which corresponds to the region of the elevator door, in the effective region may be set to the on-state and the other parts, which correspond to two sides of the elevator door, in the effective region may be set to the off-state. Thereby, the projector can project an image only to the region of the elevator door and not project an image to the regions at two sides of the elevator door.

However, in the above technique, the parts, which correspond to the regions at two sides of the elevator door, in the effective region may occupy a relatively large proportion of the effective region, and in general, all the effective region of the digital micro-mirror device is exposed to the incident light. Therefore, if the parts, which correspond to the non-predetermined projection region, in the effective region are set to the off-state, it will significantly reduce the utilization rate of the effective region, which will result in loss of brightness and resolution.

The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.

<CIT> presents a projection apparatus capable of projecting an image on a screen including a light valve and a projection lens. The light valve is capable of generating an image beam. The projection lens is disposed in a transmission path of the image beam and disposed between the light valve and the screen to project the image beam to form the image on the screen. The projection lens has an optical axis. The light valve deviates an offset of X % from the optical axis in a first direction, and the image deviates an offset of Y % from the optical axis in a second direction. The first direction is opposite to the second direction. The projection lens includes a lens group and an anamorphic device. The anamorphic device is disposed in a transmission path of the image beam and disposed between the lens group and the screen to make X %<Y %.

<CIT> presents a laser projection device comprising a laser light source, a light valve, a projection camera lens, and a mobile lens; the mobile lens is arranged between the light valve and the projection camera lens; the light valve is further used for projecting the image beam formed after modulation to the mobile lens; and the mobile lens vibrates at a preset frequency so as to enable image beams corresponding to adjacent two frames of projected images passing through the mobile lens to be superposed in a staggered manner.

<CIT> presents a projection lens for projecting an image beam. The image beam is converted by a light valve from an illumination beam irradiating the light valve. The projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is disposed on a transmission path of the image beam, and has a first optical axis. The second lens group is disposed on both a transmission path of the illumination beam and the transmission path of the image beam, and between the light valve and the first lens group. The second lens group has a second optical axis. The second optical axis is inclined with respect to the first optical axis. The third lens group is disposed on the transmission path of the image beam, and between the first lens group and the second lens group. A projection apparatus is also provided.

<CIT> presents a projection type display device comprising: a light source; a modulating device for modulating an outgoing light beam from the light source corresponding to an image signal; and a projection device for causing a light beam modulated by the modulating device to be magnified and projected on the projection surface. The device includes a first lens plate and a second lens plate that are disposed on an optical path between the light source and the modulation device, and a plurality of lenses are arranged in a matrix on the first and second lens plates. The mounting position of at least one of the first and second lens plates may be adjusted in a direction intersecting the optical axis.

<CIT> presents a projection display unit that includes a body and an invisible light application unit. The body includes a projection optical system and a detection optical system. The projection optical system projects an image onto a projection surface. The detection optical system acquires an imaging signal based on invisible light. The invisible light application unit applies the invisible light along a surface in vicinity of the projection surface while being placed on a surface that is an extension of the projection surface. The body is movable with respect to an output opening of the invisible light application unit, and a position of the body is adjustable with respect to the projection surface.

The invention provides a projection device that provides a portrait image with favorable display quality.

Other objectives and advantages of the invention will be further understood from the technical features disclosed herein.

In order to achieve one or part or all of the above or other objectives, an embodiment of the invention provides a projection device including an illumination system, a light valve, and a projection lens. The illumination system is configured to provide an illumination beam. The light valve is disposed on a transmission path of the illumination beam to modulate the illumination beam into an image beam. The projection lens is disposed on a transmission path of the image beam to project the image beam out of the projection device to form a portrait image. A center of the light valve has a first offset with respect to a reference plane in a long side direction of the light valve, wherein the reference plane includes a central axis of the projection lens, and the reference plane is perpendicular to the long side direction of the light valve. A center of the portrait image has a second offset with respect to the reference plane in a long side direction of the portrait image.

The long side direction of the light valve is parallel to the long side direction of the portrait image.

The reference plane is parallel to a short side direction of the light valve.

Preferably, the reference plane may be located between an effective region of the light valve and the portrait image.

Preferably, in the long side direction of the light valve, an effective region of the light valve may have a first length, and the effective region of the light valve may be spaced from the reference plane by a first distance; and in the long side direction of the portrait image, the portrait image may have a second length, and the portrait image may be spaced from the reference plane by a second distance.

Preferably, a ratio of the first distance to the first length may be equal to a ratio of the second distance to the second length.

Preferably, the projection device may further comprise a housing configured to accommodate the illumination system, the light valve, and the projection lens.

Preferably, the housing may have a surface parallel to the portrait image, and a width direction of the surface may be parallel to a short side direction of the portrait image.

Preferably, the projection device may further comprise a light path turning element.

Preferably, the light path turning element may be configured to reflect the image beam from the projection lens to an imaging plane to form the portrait image.

Preferably, the housing comprises a light-transmissive cover plate.

Preferably, the light-transmissive cover plate may be disposed on the light path turning element and disposed on the transmission path of the image beam projected by the projection lens.

Preferably, a line connecting the center of the portrait image and any point on the light path turning element, the central axis of the projection lens, and an extension line of the center of the portrait image in the long side direction of the portrait image may be connected to form a triangle.

Preferably, a ratio of the portrait image to an effective projection region, to which an effective region of the light valve corresponds, may be greater than or equal to <NUM>%.

The aspect ratio of the portrait image is the same as an aspect ratio of an effective region of the light valve.

The difference between an aspect ratio of the portrait image and an aspect ratio of an effective region of the light valve is greater than <NUM>% and less than or equal to <NUM>%.

Based on the above, in the projection device of the embodiment of the invention, the center of the light valve is offset with respect to a reference plane that includes the central axis of the projection lens in the long side direction of the light valve instead of being offset with respect to the reference plane in the short side direction of the light valve. Therefore, the image beam projected out of the projection device can directly form a portrait image. Thus, when an application requires a portrait image, the projection device of the embodiment of the invention can be used without sacrificing brightness and resolution and therefore provide a portrait image with favorable display quality.

Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as "top," "bottom," "front," "back," etc., is used with reference to the orientation of the Figure(s) being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Unless limited otherwise, the terms "connected," "coupled," and "mounted" and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms "facing," "faces" and variations thereof herein are used broadly and encompass direct and indirect facing, and "adjacent to" and variations thereof herein are used broadly and encompass directly and indirectly "adjacent to". Therefore, the description of "A" component facing "B" component herein may contain the situations that "A" component directly faces "B" component or one or more additional components are between "A" component and "B" component. Also, the description of "A" component "adjacent to" "B" component herein may contain the situations that "A" component is directly "adjacent to" "B" component or one or more additional components are between "A" component and "B" component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

<FIG> is a schematic diagram of a projection device according to an embodiment of the invention. <FIG> is a perspective view of a projection device according to an embodiment of the invention. <FIG> is a side view showing the internal structure of the projection device of <FIG>. <FIG> is an enlarged view of the projection device of <FIG>. <FIG> is a top view showing the interior of the projection device of <FIG>. For clarity, some of the components are omitted from <FIG>.

First, referring to <FIG>, a projection device <NUM> of the present embodiment includes an illumination system <NUM>, a light valve <NUM>, and a projection lens <NUM>. The illumination system <NUM> is configured to provide an illumination beam IB. The light valve <NUM> is disposed on the transmission path of the illumination beam IB to modulate the illumination beam IB into an image beam IMB. The projection lens <NUM> is disposed on the transmission path of the image beam IMB and is configured to project the image beam IMB to an imaging plane IP (as shown in <FIG> and is, for example, a surface for presenting an image, such as a screen or a wall) to form an image. After illumination beams IB of different colors are incident on the light valve <NUM>, the light valve <NUM> converts the illumination beams IB of different colors into the image beam IMB according to the timings and transmits the image beam IMB to the projection lens <NUM>. Therefore, the image beam IMB converted by the light valve <NUM> can be projected out of the projection device <NUM> by the projection lens <NUM> to form a colored image.

In the embodiment, the illumination system <NUM> includes, for example, a light source, a wavelength conversion element, and a filter element. The light source is configured to emit a beam, the wavelength conversion element is configured to convert the beam emitted by the light source into different colored lights, and the filter element is configured to enhance the color purity of the colored light so as to form the illumination beam IB. However, in other embodiments, the illumination system <NUM> may include a plurality of different light sources to respectively emit illumination beams IB of different colors. The disclosure is not intended to limit the illumination system <NUM> to certain forms or types.

In the embodiment, the light valve <NUM> is, for example, a reflective optical modulator such as a digital micro-mirror device (DMD) and a liquid-crystal-on-silicon panel (LCOS panel). However, in other embodiments, the light valve <NUM> may be a transmissive optical modulator such as a transparent liquid crystal panel, an electro-optical modulator, a maganeto-optic modulator, and an acousto-optic modulator (AOM). The disclosure is not intended to limit the light valve <NUM> to certain forms or types.

In the embodiment, the projection lens <NUM> is, for example, one or a combination of multiple optical lenses having diopter (as shown in <FIG>). The optical lenses include, for example, non-planar lenses such as biconcave lenses, lenticular lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses, or various combinations thereof. The disclosure is not intended to limit the projection lens <NUM> to certain forms or types.

Then, referring to <FIG> and <FIG>, in the embodiment, the imaging plane IP is, for example, a screen or a wall, and the projection device <NUM> is, for example, mounted on the floor or the desktop, wherein the image beam IMB is projected upward to the imaging plane IP. However, in other embodiments, the projection lens <NUM> may be mounted at a higher position such as the ceiling, wherein the image beam IMB is projected downward to the imaging plane IP. For ease of description, <FIG> and the subsequent drawings are marked with coordinate axes, wherein the XZ plane is, for example, parallel to the floor, the desktop, or the ceiling, and the YZ plane is, for example, parallel to the screen or the wall. Therefore, the X direction and the Z direction may be regarded as the horizontal directions, and the Y direction may be regarded as the vertical direction.

As shown in <FIG>, the projection lens <NUM> projects the image beam IMB out of the projection device <NUM> and forms a portrait image <NUM> on the imaging plane IP, wherein the portrait image <NUM> refers to an image with a vertical height greater than the horizontal width. That is, the length of the image <NUM> in the Y direction is greater than the length in the Z direction, and the forming method thereof will be further described in the following paragraphs.

First, referring to <FIG>, in the long side direction of the light valve <NUM> (for example, the Y direction in the drawing), the center C1 of the light valve <NUM> has a first offset S1 with respect to a reference plane RE (for example, being parallel to the XZ plane in the drawing), wherein the reference plane RE (for example, being parallel to the XZ plane in the drawing) includes the central axis CA of the projection lens <NUM>, and the reference plane RE (for example, being parallel to the XZ plane in the drawing) is perpendicular to the long side direction (for example, the Y direction in the drawing) of the light valve <NUM>. Here, since an effective region <NUM> of the light valve <NUM> is rectangular, the long side direction of the light valve <NUM> refers to a direction parallel to the long side of the effective region <NUM> (for example, the Y direction in the drawing), and likewise the short side direction of the light valve <NUM> refers to a direction parallel to the short side of the effective region <NUM>. The short side direction of the light valve <NUM> of the embodiment is, for example, parallel to the X direction in the drawing. However, in other embodiments, the short side direction of the light valve <NUM> may be inclined with respect to the X direction in the drawing and parallel to the XZ direction in the drawing. In addition, the effective region <NUM> of the light valve <NUM> refers to an actual optical operation region that can convert the illumination beam IB into the image beam IMB and transmit the image beam IMB to the projection lens <NUM>. For example, if the light valve <NUM> is, for example, a digital micro-mirror device (DMD), the effective region <NUM> is, for example, a region on the digital micro-mirror device (DMD) for disposing a digital micro-mirror.

Further, referring to <FIG>, in the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing), the center C2 of the portrait image <NUM> has a second offset S2 with respect to the reference plane RE (for example, being parallel to the XZ plane in the drawing). Here, the long side direction of the portrait image <NUM> refers to a direction parallel to the long side of the portrait image <NUM> (for example, the Y direction in the drawing), and likewise the short side direction of the portrait image <NUM> refers to a direction parallel to the short side of the portrait image <NUM> (for example, the Z direction in the drawing).

Specifically, the center C1 of the light valve <NUM> is offset with respect to the reference plane RE (for example, being parallel to the XZ plane in the drawing) that includes the central axis CA of the projection lens <NUM> in the long side direction of the light valve <NUM> (for example, the Y direction in the drawing) instead of being offset with respect to the reference plane RE (for example, being parallel to the XZ plane in the drawing) in the short side direction of the light valve <NUM> (for example, the X direction in the drawing). Furthermore, the long side direction of the light valve <NUM> (for example, the Y direction in the drawing) is parallel to the vertical direction (for example, the Y direction in the drawing). Therefore, the image beam IMB projected out of the projection device <NUM> can directly form the portrait image <NUM> on the imaging plane IP. Thus, when an application requires a portrait image (for example, elevator door projection), the projection device <NUM> of the embodiment of the invention can be used without sacrificing brightness and resolution and therefore provide the portrait image <NUM> with favorable display quality.

It should be noted that since the image projected by the projection device <NUM> is a portrait image, even if the portrait image <NUM> needs to be limited to a predetermined portrait projection region (for example, the area of an elevator door or an advertising lightbox), the utilization rate of the effective region <NUM> of the light valve <NUM> is still relatively high. In the case where the light valve is a digital micro-mirror device (DMD), the digital micro-mirror on the effective region <NUM> can transmit the corresponding image beam IMB to the projection lens <NUM> when it is in the on-state, and guide the corresponding beam outside the projection lens <NUM> when it is in the off-state. That is to say, only a small part of the effective region <NUM> may be set to the off-state. In some embodiments, the ratio of the portrait image <NUM> to the effective projection region to which the effective region <NUM> of the light valve <NUM> corresponds may at least be greater than or equal to <NUM>%, for example. In some embodiments, the ratio of the portrait image <NUM> to the effective projection region to which the effective region <NUM> of the light valve <NUM> corresponds may at least be greater than or equal to <NUM>%, for example. Here, the effective projection region to which the effective region <NUM> of the light valve <NUM> corresponds refers to the region where the image beam IMB can form an image on the imaging plane IP when the effective region <NUM> of the light valve <NUM> is all set to the on-state.

In some embodiments, the difference between the aspect ratio of the portrait image <NUM> and the aspect ratio of the effective region <NUM> of the light valve <NUM> is greater than <NUM>% and less than or equal to <NUM>%, for example. Alternatively, in some embodiments, the aspect ratio of the portrait image <NUM> and the aspect ratio of the effective region <NUM> of the light valve <NUM> are substantially the same. That is to say, in some embodiments, the effective region <NUM> of the light valve <NUM> may all be set to the on-state, and it is not required to set a part of the effective region <NUM> to the off-state, so as to achieve better light utilization rate.

Referring to <FIG> and <FIG>, the long side direction of the light valve <NUM> (for example, the Y direction in the drawing) is parallel to the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing) and perpendicular to the short side direction of the portrait image <NUM> (for example, the Z direction in the drawing). The short side direction of the light valve <NUM> (for example, the X direction in the drawing) is perpendicular to the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing) and perpendicular to the short side direction of the portrait image <NUM> (for example, the Z direction in the drawing). The central axis CA of the projection lens <NUM> is perpendicular to the long side direction of the light valve <NUM> (for example, the Y direction in the drawing) and parallel to the short side direction of the light valve <NUM> (for example, the X direction in the drawing). The reference plane RE (for example, being parallel to the XZ plane in the drawing) is perpendicular to the long side direction of the light valve <NUM> (for example, the Y direction in the drawing) and parallel to the short side direction of the light valve <NUM> (for example, the X direction in the drawing). It should be noted that, in other embodiments, the short side direction of the light valve <NUM> may be parallel to the XZ direction in the drawing but inclined with respect to the X direction in the drawing. Then, the short side direction of the light valve <NUM> may not be perpendicular to the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing) nor perpendicular to the short side direction of the portrait image <NUM> (for example, the Z direction in the drawing), and the central axis CA of the projection lens <NUM> is not parallel to the short side direction of the light valve <NUM>.

In the embodiment, the reference plane RE (for example, being parallel to the XZ plane in the drawing) is located between the effective region <NUM> of the light valve <NUM> and the portrait image <NUM>. In the long side direction of the light valve <NUM> (for example, the Y direction in the drawing), the effective region <NUM> of the light valve <NUM> has a first length L1, and the effective region <NUM> of the light valve <NUM> is spaced from the reference plane RE (for example, being parallel to the XZ plane in the drawing) by a first distance D1. That is, the short side of the effective region <NUM> of the light valve <NUM>, which is closest to the reference plane RE, is spaced from the reference plane RE by the first distance D1. In the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing), the portrait image <NUM> has a second length L2, and the portrait image <NUM> is spaced from the reference plane RE (for example, being parallel to the XZ plane in the drawing) by a second distance D2. That is, the short side of the portrait image <NUM>, which is closest to the reference plane RE, is spaced from the reference plane RE by the second distance D2, wherein the ratio of the first distance D1 to the first length L1 is substantially equal to the ratio of the second distance D2 to the second length L2.

In addition, the projection device <NUM> further includes a housing <NUM> for accommodating the illumination system <NUM> (not shown), the light valve <NUM>, and the projection lens <NUM>. The housing <NUM> has a surface 230a and/or a surface 230b parallel to the portrait image <NUM>. The surface 230a of the housing <NUM> faces the portrait image <NUM>, and the surface 230b of the housing <NUM> faces away from the portrait image <NUM> and is opposite to the surface 230a. The width direction of the surface 230a and/or the surface 230b (referring to <FIG>; for example, the Z direction in the drawing) is parallel to the short side direction of the portrait image <NUM> (for example, the Z direction in the drawing). In the embodiment, the surface 230a and/or the surface 230b of the housing <NUM> is, for example, rectangular, and the horizontal width of the surface 230a and/or the surface 230b is greater than the vertical height thereof. Therefore, the width direction of the surface 230a and/or the surface 230b refers to the long side direction of the surface 230a and/or the surface 230b, that is, a direction parallel to the long side of the surface 230a and/or the surface 230b (for example, the Z direction in the drawing). However, in other embodiments, the horizontal width of the surface 230a and/or the surface 230b of the housing <NUM> may be, for example, less than the vertical height thereof. Therefore, the width direction of the surface 230a and/or the surface 230b refers to the short side direction of the surface 230a and/or the surface 230b, that is, a direction parallel to the short side of the surface 230a and/or the surface 230b. Nevertheless, in other embodiments, the horizontal width of the surface 230a and/or the surface 230b of the housing <NUM> may be equal to the vertical height thereof, for example, but the invention is not limited thereto.

As shown in <FIG>, the projection device <NUM> further includes a light path turning element <NUM> for reflecting the image beam IMB from the projection lens <NUM> to the imaging plane IP so as to form the aforementioned portrait image <NUM>. The light path turning element <NUM> is, for example, a concave mirror. As shown in <FIG>, a line connecting the center C2 of the portrait image <NUM> and any point on the light path turning element <NUM>, the central axis CA of the projection lens <NUM>, and an extension line of the center C2 of the portrait image <NUM> in the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing) are connected to form a triangle. Here, the extension line of the center C2 of the portrait image <NUM> in the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing) is, for example, a line connecting the center C2 of the portrait image <NUM> and the central axis CA of the projection lens <NUM> in the long side direction of the portrait image <NUM> (for example, the Y direction in the drawing). That is to say, the central axis CA of the projection lens <NUM> and the center C2 of the portrait image <NUM> are located on the same vertical plane (for example, the XY plane in the drawing).

In addition, as shown in <FIG> and <FIG>, the housing <NUM> of the projection device <NUM> may include a light-transmissive cover plate <NUM> that is disposed on the light path turning element <NUM> and disposed on the transmission path of the image beam IMB projected by the projection lens <NUM>. The light-transmissive cover plate <NUM> prevents dust from adhering to the light path turning element <NUM> to avoid influence on the optical efficiency of the projection device <NUM>.

Moreover, in some embodiments, the projection device <NUM> may optionally include an optical element having a function of light concentration, refraction, or reflection for guiding the illumination beam IB from the illumination system <NUM> to the light valve <NUM> and/or for guiding the image beam IMB from the light valve <NUM> to the projection lens <NUM>. For example, as shown in <FIG>, the projection device <NUM> further includes an optical mirror group <NUM>. The optical mirror group <NUM> is disposed on the transmission path of the illumination beam IB from the illumination system <NUM> to guide the illumination beam IB to the light valve <NUM> and guide the image beam IMB from the light valve <NUM> to the projection lens <NUM>. It should be noted that, in order to clearly show the position of the light valve <NUM>, the optical mirror group <NUM> is omitted from <FIG> and <FIG>. In addition, the position of the illumination system <NUM> shown in <FIG> is merely an example and is not intended to limit the actual position of the illumination system <NUM>. For example, a part of the illumination system <NUM> may be disposed above or under the optical mirror group <NUM> in the Y direction in the drawing. Nevertheless, the invention is not limited thereto.

In conclusion, in the projection device of the embodiment of the invention, the center of the light valve is offset with respect to the reference plane that includes the central axis of the projection lens in the long side direction of the light valve instead of being offset with respect to the reference plane in the short side direction of the light valve. Furthermore, the long side direction of the light valve is parallel to the vertical direction. Therefore, the image beam projected out of the projection device directly forms a portrait image on the imaging plane. As a result, when used for an application that requires a portrait image (for example, elevator door projection or portrait billboard projection), the projection device of the embodiment of the invention can be used without sacrificing brightness and resolution and therefore provide a portrait image with favorable display quality.

Claim 1:
A projection device (<NUM>), comprising:
an illumination system (<NUM>) providing an illumination beam (IB);
a light valve (<NUM>) disposed on a transmission path of the illumination beam (IB) to modulate the illumination beam (IB) into an image beam (IMB); and
a projection lens (<NUM>) disposed on a transmission path of the image beam (IMB) to project the image beam (IMB) out of the projection device (<NUM>) to form a portrait image (<NUM>), wherein a short side direction of the light valve (<NUM>) is parallel to a short side direction of an effective region (<NUM>) of the light valve (<NUM>), the central axis (CA) of the projection lens (<NUM>) is perpendicular to a long side direction of the light valve (<NUM>) and is parallel to the short side direction of the light valve (<NUM>), wherein an aspect ratio of the portrait image (<NUM>) is the same as an aspect ratio of an effective region (<NUM>) of the light valve (<NUM>) or a difference between an aspect ratio of the portrait image (<NUM>) and an aspect ratio of the effective region (<NUM>) of the light valve (<NUM>) is greater than <NUM>% and less than or equal to <NUM>%;
wherein a center (C1) of the light valve (<NUM>) has a first offset (S1) with respect to a reference plane (RE) in the long side direction of the light valve (<NUM>), wherein the reference plane (RE) comprises the central axis (CA) of the projection lens (<NUM>), and the reference plane (RE) is perpendicular to the long side direction of the light valve (<NUM>); and
wherein a center (C2) of the portrait image (<NUM>) has a second offset (S2) with respect to the reference plane (RE) in a long side direction of the portrait image (<NUM>).