A conventional system or device for displaying an image, such as a display, projector, or other imaging system, is frequently used to display a still or video image. Viewers evaluate display systems based on many criteria such as image size, contrast ratio, color purity, brightness, pixel color accuracy, and resolution. Image brightness, pixel color accuracy, and resolution are particularly important metrics in many display markets because the available brightness, pixel color accuracy, and resolution can limit the size of a displayed image and control how well the image can be seen in venues having high levels of ambient light.
A conventional display system produces a displayed image by addressing an array of pixels arranged in horizontal rows and vertical columns. Because pixels have a rectangular shape, it can be difficult to represent a diagonal or curved edge of an object in an image that is to be displayed without giving that edge a stair-stepped or jagged appearance. Furthermore, if one or more of the pixels of the display system is defective, the displayed image will be affected by the defect. For example, if a pixel of the display system exhibits only an “off” position, the pixel may produce a solid black square in the displayed image. The undesirable results of pixel geometry and pixel inaccuracy are accentuated when the displayed image is projected onto a large viewing surface in color.
A projection assembly including a light modulator assembly that includes a dichroic beam splitter, including first and second dichroic surfaces, the dichroic surfaces being crossed relative to one another, and first, second, and third light modulator panels in optical communication with the dichroic beam splitter, and a wobbling polarized plate at an optical pupil of said light modulator assembly in optical communication with the light modulator assembly.
The accompanying drawings illustrate various embodiments of the present apparatus and method and are a part of the specification. The illustrated embodiments are merely examples of the present apparatus and method and do not limit the scope of the disclosure.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
A projection assembly is provided herein for use with projection assemblies and display systems such as televisions, projectors, etc. According to an exemplary embodiment, the projection assembly includes a wobbling directing member that directs multi-component light from crossed dichroic surfaces. The crossed dichroic surfaces are configured to split multi-component light into several components and direct each component to a corresponding light modulator panel. Each light modulator panel modulates the component light to form a sub-image. The sub-images are then directed back through the dichroic beam splitter and to the wobbling directing member. The wobbling directing member selectively shifts the path of sub-images between the wobbling device and display optics to form images of relatively higher resolution than the native resolution of the modulator.
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present method and apparatus. It will be apparent, however, to one skilled in the art, that the present method and apparatus may be practiced without these specific details. Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearance of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
Display System
While one image is illustrated and described as being processed by the image processing unit (110), it will be understood by one skilled in the art that a plurality or series of images may be processed by the image processing unit (110). The image processing unit (110) performs various functions including controlling the operation of a wobbling plate (120) and controlling a spatial light modulator (SLM) assembly (130).
The display system (100) also includes a light source module (140). The light source module (140) generates multi-component light and directs the multi-component light through the wobbling plate (120) and to the SLM assembly (130). The terms “SLM” and “modulator” will be used interchangeably herein to refer to a spatial light modulator assembly. The incident light is split into individual components, such as red, green, and blue components. These components are then directed to corresponding modulator panels. The incident light may be modulated in its color, frequency, phase, intensity, polarization, or direction by the modulator panels. The SLM assembly (130) includes a plurality of individual light modulator panels that are in optical communication with a dichroic beam splitter.
For example, according to one exemplary embodiment, the SLM assembly (130) includes crossed dichroic surfaces that split the white light directed to the SLM assembly (130) from the light source module (140) into component beams, and then direct the component beams, such as a red beam, a blue beam, and a green beam, to corresponding light modulator panels. Further, according to an exemplary embodiment discussed below, the crossed dichroic surfaces may be formed on a dichroic cube or a dichroic cube. The modulated light is then directed from the dichroic cube or cube back to the wobbling plate (120).
The wobbling plate (120) then spatially shifts the path of the modulated light between the wobbling plate (120) and the display optics (150). By selectively shifting the path of the modulated light with the wobbling plate (120), the display system is able to produce images of relatively high resolution compared to images produced by systems without a wobbling plate (120). The spatially shifting modulated light is then focused on a display surface by the display optics (150) to form a displayed image.
The display optics (150) may include any device configured to display or project an image. For example, the display optics (150) may be, but are not limited to, a lens configured to project and focus an image onto a viewing surface. The viewing surface may be, but is not limited to, a screen, television such as a rear projection type television, wall, liquid crystal display (LCD), or computer monitor. An exemplary method of modulating light in a spatial light modulator will now be discussed.
Light Modulator Assembly Having a Dichroic Cube
Accordingly, the present exemplary light modulator assembly (200) is a three-panel type light modulator assembly. As will be discussed in more detail below, the dichroic cube (205) splits light into its component colors and directs each component color to an associated modulator.
The dichroic cube (205) includes a first dichroic surface (225) and a second dichroic surface (230). In particular, according to the present exemplary embodiment, the first dichroic surface (225) and second dichroic surface (230) are formed on first, second, third, and fourth prisms (235-1, 235-2, 235-3, 2354). The resulting first and second dichroic surfaces (225, 230) form a cross.
The first dichroic surface (225), according to the first exemplary embodiment, is configured to transmit green and blue light and to reflect red light. In particular, the first dichroic surface (225) may include a dichroic layer formed on glass or other suitable transparent or semi-transparent material as is well known in the art.
The second dichroic surface (230) is configured to transmit red and green light and to reflect blue light. In particular, the second dichroic surface (230) may include a dichroic layer formed on glass or other suitable transparent or semi-transparent material.
White light (245) is directed to the light modulator assembly (200) from a light source module (140;
The blue/green beam (250) is directed through the second prism (235-2) until it is incident on the second dichroic surface (230). As introduced, the second dichroic surface (230) is configured to transmit green and red light and to reflect blue light. Consequently, the second dichroic surface (230) splits the blue/green beam (250) into a blue beam (260), which is reflected, and a green beam (265), which is passed into the third prism (235-3).
The reflected blue beam (260) is directed to the blue modulator panel (210), while the transmitted green beam (265) is directed to the green modulator panel (215). According to the present exemplary embodiment, an optional blue filter (270-1) is placed between the dichroic cube (205) and the blue modulator panel (210), and an optional green filter (270-2) is placed between the dichroic cube (205) and the green modulator panel (215). The filters (270-1, 270-2) reduce the amount of stray light directed to each modulator panel. Accordingly, the blue and green portions of white light (245) incident on the first dichroic surface (225) are split and directed to the blue and green modulator panels (210, 215) respectively.
The red portion (248) of white light (245) incident on the first dichroic surface (225) of the first prism (235-1) is reflected away therefrom. In particular, the reflected red beam (248) is directed through the first prism (235-1) to the second dichroic surface (230). The second dichroic surface (230) transmits the red beam (248) and directs it to the red modulator panel (220). According to the present exemplary embodiment, an optional red filter (270-3) is placed between the dichroic cube (205) and the red modulator panel (220). The red filter (270-3) minimizes stray or non-red light that reaches the red modulator panel (220).
The second dichroic surface (230) is also configured to split white light (245) that is incident thereon in the first prism (235-1). In particular, when white light (245) is directed to the second dichroic surface (230) of the first prism (235-1) a red/green beam (275) is transmitted to the fourth prism (235-4) while a blue beam (260) is reflected.
The reflected blue beam (260) is directed across the first prism (235-1) to the first dichroic surface (225). The first dichroic surface (225) transmits the blue beam (260) through the second prism (235-2) to the blue modulator panel (210).
The red/green beam (275) from the first prism (235-1) is directed to the first dichroic surface (225) in the fourth prism (235-4). This red/green beam (275) is then split into two beams. One beam includes a reflected red beam (248), which is directed through the red filter (270-3) to the red modulator panel (220). The second beam includes a transmitted green beam (265), which is directed through the third prism (235-3) and the green filter (270-2) to the green modulator panel (215).
The light directed to red, green, and blue modulator panels (210, 215, 220) is then modulated to form individual sub-images. An exemplary projection assembly that includes a wobbling polarized plate (300;
On-Axis Projection Assembly
As seen in
Thereafter, according to the present exemplary embodiment, as the polarized white light (345) is directed toward the light modulator assembly (200), it passes through the ¼ wave plate (320) and the coupling lens assembly (330). The ¼ wave plate changes the polarization of the linearly polarized light to circularly polarized.
After the polarized white light (345) is passed initially through the ¼ wave plate (320), the polarized white light (345) is directed to the coupling lens assembly (330). The coupling lens assembly (330) focuses it onto the light modulator assembly (200). The light modulator assembly splits the polarized white light (345) and directs the component beams onto the red, green, and blue modulator panels (210, 215, 220).
The modulated component beams are then returned along substantially the same paths as taken to the modulator panels. This modulated light exits the light modulator assembly (200) and is directed to the coupling lens assembly (330). The coupling lens assembly (330) collimates and combines the output of each of the modulator panels (210, 215, 220) exiting the light modulator assembly (200) into a modulated light beam (350) and directs the modulated light beam (350) to the ¼ wave plate (320).
As the modulated light (350) passes through the ¼ wave plate (320), the polarization of modulated light is again rotated, such that the modulated light (350) has a polarization that is orthogonal to that of the linearly polarized white light (345).
This orthogonal polarized modulated light is then directed to the wobbling polarized plate (310). As previously discussed, the wobbling polarized plate (310) is configured to reflect light having the polarization and orientation of the light initially directed thereto. In addition, the wobbling polarized plate (310) is configured to transmit light having an orthogonal orientation. As discussed, the ¼ wave plate (320) rotates the polarization of the modulated light, such that it is orthogonal that of the entering polarized white light (345).
Accordingly, in addition to transmitting light from a light source module to the light modulator assembly, the wobbling polarized plate (310) reflects the modulated light to the display optics assembly (340). The display optics assembly (340) directs the modulated light onto a display surface to form a full-color image thereon. In addition, the location of the wobbling polarized plate (310) at or near the optical pupil of the projection assembly (200) allows the wobbling polarized plate also to selectively shift the path of modulated light to thereby increase the resolution of the projected image relative to the native resolution of the light modulator assembly (200).
More specifically, as introduced, the wobbling polarized plate (310) also has wobulator control coupled thereto. Wobulator control, or wobulation, refers to a process of shifting the position of a light path relative to the wobbling polarized plate (310). In other words, the imaging processing unit (110;
In one embodiment, as illustrated in
As illustrated in
Thus, by generating a first and second sub-frame (400, 500) and displaying the two sub-frames in the spatially offset manner as illustrated in
In addition, the display system (100;
Thus, as shown by the examples in
In addition, by overlapping pixels of image sub-frames, the display system (100;
In conclusion, a projection assembly has been discussed herein for use with projection assemblies and display systems such as televisions, projectors, etc. According to an exemplary embodiment, the projection assembly includes a wobbling directing member that directs multi-component light to crossed dichroic surfaces. The crossed dichroic surfaces are configured to split multi-component light into several components and direct each component to a corresponding light modulator panel. Each light modulator panel modulates the component light to form a sub-image. The sub-images are then directed back through the dichroic beam splitter and to the wobbling directing member. The wobbling directing member selectively shifts the path of sub-images between the wobbling device and display optics to form images of relatively high resolution.
The preceding description has been presented only to illustrate and describe the present method and apparatus. It is not intended to be exhaustive or to limit the disclosure to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the disclosure be defined by the following claims.