TWI872929B - Projection display device and optical shielding element thereof - Google Patents

Abstract

An optical shielding element is disclosed and designed for use in a projection display device. The projection display device includes a light-emitting unit and a digital micromirror device. The light-emitting unit projects incident light onto the digital micromirror device, causing the digital micromirror device to reflect the incident light and project an image. The optical shielding component includes a frame and a coating layer. The frame includes a body and a hollow portion. The body surrounds and forms the hollow portion. The body includes an inner surface and a notch. The inner surface is arranged corresponding to the hollow portion. The frame is attached on the digital micromirror device. The notch is recessed from the inner surface in a direction away from the hollow portion. The coating layer is disposed on the body of the frame. The roughness of the coating layer is less than 500 nanometers, the reflectance of the coating layer for incident light is less than 5%, and the transmittance of the coating layer for incident light is less than 1%.

Description

Projection display device and optical shielding member thereof

The present invention relates to a projection display device, and more particularly to a projection display device having an optical shielding member.

Currently, digital light processing (DLP) imaging technology has been widely used in projection display devices. Generally speaking, in digital light processing projection display devices, images are generated by reflecting light from a digital micromirror device (DMD).

A conventional digital micromirror device includes a substrate and a plurality of micro-reflective mirrors, wherein the plurality of micro-reflective mirrors are arranged in an array on the substrate and are structured to form a first region of the digital micromirror device. Each micro-reflective mirror controls a pixel in the projected image. The second region of the digital micromirror device is formed on the portion of the substrate where the micro-reflective mirrors are not arranged. When incident light is irradiated on the digital micromirror device, the micro-reflective mirrors in the first region of the digital micromirror device reflect the light and project it into an image. However, the incident light also irradiates the second region of the digital micromirror device at the same time, causing the second region to reflect the light and form stray light, which will cause interference and result in poor projection imaging quality.

In view of this, it is necessary to develop a projection display device and an optical shielding member thereof to solve the problems faced by the prior art.

The purpose of this case is to provide a projection display device and an optical shielding member thereof, which can reduce the generation of stray light to improve the projection imaging quality.

To achieve the aforementioned purpose, one general implementation of the present case is to provide an optical shielding member suitable for a projection display device, wherein the projection display device includes a light-emitting unit and a digital micromirror device. The light-emitting unit projects an incident light onto the digital micromirror device, causing the digital micromirror device to reflect the incident light and project an image. The optical shielding member includes a frame and a coating layer. The frame includes a main body and a hollow portion. The main body surrounds the hollow portion. The main body includes a first surface, a second surface, an inner surface and a notch. The first surface and the second surface are two opposite surfaces of the main body. The inner surface is connected to the first surface and is arranged corresponding to the hollow portion. The second surface of the main body is attached to the digital micromirror device. The notch is formed by the inner surface being recessed in a direction away from the hollow portion. The coating layer is disposed on the first surface of the main body. The roughness of the coating layer is less than 500 nanometers, the reflectivity of the coating layer to the incident light is less than 5%, and the transmittance of the coating layer to the incident light is less than 1%.

To achieve the above-mentioned purpose, another general implementation of the present case is to provide a projection display device, including a digital micromirror device, a light-emitting unit and an optical shielding member. The digital micromirror device includes a substrate and a plurality of micro-reflective mirrors. The plurality of micro-reflective mirrors are arranged in an array on the substrate to form a first area of the digital micromirror device. The second area of the digital micromirror device is formed in a portion of the substrate where the micro-reflective mirrors are not arranged. The light-emitting unit is configured to project incident light onto the digital micromirror device, so that the plurality of micro-reflective mirrors in the first area of the digital micromirror device reflect the incident light to project an image. The optical shielding member is arranged in the digital micromirror device and includes a frame and a coating layer, wherein the frame includes a body and a hollow portion, and the body surrounds the hollow portion. The main body includes a first surface, a second surface, an inner surface and a notch. The first surface and the second surface are two opposite surfaces of the main body. The inner surface is connected to the first surface and is arranged corresponding to the hollow portion. The second surface of the main body is attached to the digital microscope device. The notch is formed by the inner surface being concave in a direction away from the hollow portion. The coating layer is arranged on the first surface of the main body. The roughness of the coating layer is less than 500 nanometers, the reflectivity of the coating layer to the incident light is less than 5%, and the transmittance of the coating layer to the incident light is less than 1%.

Some typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different aspects without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially for illustrative purposes rather than for limiting the present invention.

FIG. 1 is a schematic diagram of the structure of a projection display device of an embodiment of the present invention, and FIG. 2 is a partially enlarged cross-sectional schematic diagram of the digital micromirror device and the optical shield of the projection display device shown in FIG. As shown in FIG. 1 and FIG. 2, the projection display device 100 of the present embodiment includes a digital micromirror device 1, a light-emitting unit 2, and an optical shield 3. The digital micromirror device 1 includes a substrate 11 and a plurality of micro-reflective mirrors 12. The plurality of micro-reflective mirrors 12 are arranged in an array on the substrate 11 to form a first region A of the digital micromirror device 1. The second region B of the digital micromirror device 1 is formed on the portion of the substrate 11 where the micro-reflective mirrors 12 are not arranged. The light-emitting unit 2 is configured to project the incident light onto the digital micro-mirror device 1, so that the plurality of micro-reflective lenses 12 in the first area A of the digital micro-mirror device 1 reflect the incident light and project the incident light onto a projection screen (not shown) through a lens (not shown) to form an image. In this embodiment, the projection display device 100 further includes a lens set 4, wherein the lens set 4 is configured to converge the incident light and project the light onto the digital micro-mirror device 1.

FIG. 3 is a schematic diagram of the structure of the optical shielding member of the projection display device shown in FIG. 1, and FIG. 4 is a schematic diagram of the structure of the optical shielding member of the projection display device shown in FIG. 1 at another viewing angle. As shown in FIG. 1 to FIG. 4, the optical shielding member 3 of this embodiment is disposed on the digital microscope device 1, and includes a frame 31 and a coating layer 32. The frame 31 includes a body 311 and a hollow portion 312. The body 311 of the frame 31 surrounds the hollow portion 312. The body 311 of the frame 31 includes a first surface 311a, a second surface 311b, an inner surface 311c and a notch 311d. The first surface 311a and the second surface 311b are two opposite surfaces of the body 311. The inner surface 311c is connected to the first surface 311a and is disposed corresponding to the hollow portion 312 of the frame 31. The second surface 311b of the body 311 is attached to the digital microscope device 1 and is disposed corresponding to the second area B. The hollow portion 312 of the frame 31 is disposed corresponding to the first area A. The notch 311d is formed by the inner surface 311c being recessed in a direction away from the hollow portion 312. By providing the notch 311d, the area of the inner surface 311c of the body 311 is reduced, thereby reducing stray light generated by reflection of the inner surface 311c of the body 311 when the incident light projected onto the digital microscope device 1 is reflected by the inner surface 311c of the body 311, so as to improve the projection imaging quality.

As shown in FIGS. 1 to 4 , the coating layer 32 of this embodiment is disposed on the first surface 311a of the body 311 of the frame 31. In this embodiment, the roughness of the coating layer 32 is less than 500 nanometers (nm), preferably between 1 nanometer (nm) and 500 nanometers (nm), but not limited thereto. Since the roughness of the coating layer 32 is less than 500 nanometers (nm), the coating layer 32 forms a surface close to a mirror surface, so that the light reflected by the coating layer 32 is evenly reflected in the same direction, reducing the generation of stray light, so as to improve the projection imaging quality. In addition, the coating layer 32 of this embodiment is a thin film structure with an extremely small thickness, which can reduce the stray light reflected by the thickness of the coating layer 32 and improve the quality of projection imaging. Compared with other surface treatment methods, such as matte spray paint, the coating layer 32 of this embodiment has low roughness and low thickness, and can form a surface close to a mirror surface, which has a better effect of suppressing stray light and better projection imaging quality. For the convenience of understanding and explanation, the coating layer 32 shown in Figures 2 and 4 is drawn with a clearly visible thickness, but this does not limit the coating layer 32 of this case to have a thickness visible to the naked eye. In fact, in this embodiment, the thickness of the coating layer 32 is extremely small and difficult to be directly seen with the naked eye.

In this embodiment, the reflectivity of the coating layer 32 to the incident light is less than 5%, preferably between 0.1% and 5%, but not limited thereto. Since the reflectivity of the coating layer 32 to the incident light is less than 5%, the incident light irradiated on the coating layer 32 is mostly absorbed, reducing the generation of stray light to improve the projection imaging quality. In one embodiment, the coating layer 32 of the optical shielding member 3 is a black coating layer to reduce the reflectivity, but not limited thereto.

In this embodiment, the transmittance of the coating layer 32 to the incident light is less than 1%, preferably between 0.01% and 1%, but not limited thereto. Since the transmittance of the coating layer 32 to the incident light is less than 1%, the incident light can be reduced from penetrating the coating layer 32 and projecting onto the portion of the substrate 11 corresponding to the second region B, thereby reducing the generation of stray light and improving the projection imaging quality.

As shown in FIG. 3 and FIG. 4, in this embodiment, the frame 31 of the optical shielding member 3 is, for example but not limited to, a rectangular frame. The body 311 of the frame 31 includes a first side plate 311e, a second side plate 311f, a third side plate 311g, and a fourth side plate 311h. The first side plate 311e is disposed opposite to the second side plate 311f, and the third side plate 311g is disposed opposite to the fourth side plate 311h. The two ends of the third side plate 311g are respectively connected to the first side plate 311e and the second side plate 311f. The two ends of the fourth side plate 311h are respectively connected to the first side plate 311e and the second side plate 311f. The first side plate 311e, the second side plate 311f, the third side plate 311g and the fourth side plate 311h surround to form a hollow portion 312. The frame 31 of this embodiment is a rectangular frame, which has a simple structure and is easy to manufacture, and has a high structural strength.

In one embodiment, the area of the hollow portion 312 of the optical shielding member 3 is larger than the area of the first area A of the digital microscope device 1, so as to prevent the optical shielding member 3 from shielding the micro reflective lens 12 in the first area A, thereby improving the imaging quality. In one embodiment, the area of the hollow portion 312 of the optical shielding member 3 is equal to the area of the first area A of the digital microscope device 1. In other words, the hollow portion 312 of the optical shielding member 3 and the first area A of the digital microscope device 1 are aligned and their contours match each other, thereby reducing the gap between the optical shielding member 3 and the first area A of the digital microscope device 1, thereby improving the projection imaging quality. In one embodiment, the area of the frame 31 of the optical shielding member 3 is equal to the area of the second region B of the digital microscope device 1, but the present invention is not limited thereto.

In some embodiments, the body 311 of the frame 31 is a light-proof plate and is made of a metal material, wherein the metal material is, for example but not limited to, aluminum, aluminum alloy or other metal alloys. In one embodiment, the body 311 of the frame 31 can be made of a glass material.

FIG. 5 is a partially enlarged cross-sectional structural diagram of the optical shielding member of the projection display device shown in FIG. 4 at section C-C, wherein section C-C is respectively perpendicular to the first surface 311a and the inner surface 311c of the body 311. In this embodiment, as shown in FIG. 3 to FIG. 5, the notch 311d of the body 311 of the frame 31 is, for example but not limited to, a rectangular cross-sectional notch (indicated by a dotted line filled portion), which is easy to manufacture and has a low cost.

FIG. 6 is a partially enlarged cross-sectional structural schematic diagram of an optical shielding member of a variation of the present invention. The frame 31a shown in FIG. 6 is similar in structure to the frame 31 shown in FIG. 5, wherein the same symbols represent the same components and functions, and therefore no further description is given here. Unlike the frame 31 shown in FIG. 5, the notch 311d of the body 311 of the frame 31a of this variation is a fan-shaped cross-sectional notch (indicated by the dotted line filled portion). Since the inner wall of the body 311 corresponding to the notch 311d is a continuous curved surface, it can prevent the light from being reflected multiple times by multiple surfaces, thereby reducing the generation of stray light.

FIG. 7 is a partially enlarged cross-sectional structural schematic diagram of an optical shielding member of another variation of the present invention. The frame 31b shown in FIG. 7 is similar in structure to the frame 31 shown in FIG. 5, wherein the same symbols represent the same components and functions, and therefore will not be described in detail here. Unlike the frame 31 shown in FIG. 5, the notch 311d of the body 311 of the frame 31b of this variation is, for example but not limited to, a triangular cross-sectional notch (indicated by a dotted line filled portion). Since the inner wall of the body 311 corresponding to the notch 311d is a continuous plane, it is possible to avoid multiple reflections of light by multiple surfaces to reduce the generation of stray light. In addition, a triangular cross-sectional notch is easy to manufacture and has a lower cost. In some embodiments, the notch 311d of the body 311 may be a polygonal cross-sectional notch or an irregular cross-sectional notch, but is not limited thereto.

In summary, the present invention provides a projection display device and an optical shielding member thereof, wherein the optical shielding member includes a frame and a coating layer. The notch of the main body of the frame is formed by the inner surface of the main body being recessed in a direction away from the hollow portion, so that the area of the inner surface of the main body is reduced, so as to reduce the stray light generated by the incident light projected onto the digital micromirror device being reflected by the inner surface of the main body, so as to improve the projection imaging quality. In addition, the roughness of the coating layer of the optical shielding member is less than 500 nanometers, so that the coating layer forms a surface close to a mirror surface, so that the light reflected by the coating layer is evenly reflected in the same direction, reducing the generation of stray light, so as to improve the projection imaging quality. Furthermore, the reflectivity of the coating layer to the incident light is less than 5%, so that the incident light irradiated on the coating layer is mostly absorbed, reducing the generation of stray light, so as to improve the quality of projection imaging. Moreover, the transmittance of the coating layer to the incident light is less than 1%, which can reduce the incident light penetrating the coating layer and being reflected by the substrate portion corresponding to the second area, so as to reduce the generation of stray light, so as to improve the quality of projection imaging.

This case can be modified in various ways by a person familiar with this technology, but all of them will not deviate from the scope of protection sought by the attached patent application.

100: projection display device 1: digital micromirror device 11: substrate 12: micro reflective lens 2: light-emitting unit 3: optical shielding member 31, 31a, 31b: frame 311: body 311a: first surface 311b: second surface 311c: inner surface 311d: notch 311e: first side plate 311f: second side plate 311g: third side plate 311h: fourth side plate 312: hollow part 32: coating layer 4: lens group A: first region B: second region C-C: cross section

FIG. 1 is a schematic diagram of the structure of a projection display device of an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional structural diagram of a digital micro-mirror device and an optical shield of the projection display device shown in FIG. FIG. 3 is a schematic diagram of the structure of the optical shield of the projection display device shown in FIG. FIG. 4 is a schematic diagram of the structure of the optical shield of the projection display device shown in FIG. 1 at another viewing angle. FIG. 5 is a schematic diagram of the partially enlarged cross-sectional structure of the optical shield of the projection display device shown in FIG. 4 at section C-C, wherein section C-C is perpendicular to the first surface and the inner surface of the body, respectively. FIG. 6 is a schematic diagram of the partially enlarged cross-sectional structure of an optical shield of a variation of the present invention. FIG. 7 is a schematic diagram of the partially enlarged cross-sectional structure of an optical shield of another variation of the present invention.

1: Digital microscope device

11: Substrate

12: Micro reflective lens

3: Optical shielding parts

31:Frame

311:Entity

311a: first surface

311b: Second surface

311c: Inner surface

311d: Gap

312: Hollow part

32: coating layer

A: The first area

B: Second area

Claims (10)

An optical shielding member is applicable to a projection display device, wherein the projection display device comprises a light-emitting unit and a digital micromirror device, wherein the light-emitting unit projects an incident light onto the digital micromirror device, so that the digital micromirror device reflects the incident light and projects an image, wherein the optical shielding member comprises: a frame, comprising a body and a hollow portion, wherein the body surrounds the hollow portion, wherein the body comprises a first surface, a second surface, an inner surface and a notch, wherein the first surface and the second surface are two opposite surfaces of the body, wherein the inner surface is connected to the first surface and is arranged corresponding to the hollow portion, wherein the second surface of the body is attached to the digital micromirror device, wherein the notch is formed by the inner surface being recessed in a direction away from the hollow portion; and A coating layer is disposed on the first surface of the body, wherein the roughness of the coating layer is less than 500 nanometers, the reflectivity of the coating layer to the incident light is less than 5%, and the transmittance of the coating layer to the incident light is less than 1%. An optical shield as described in claim 1, wherein the coating layer is a black coating layer. An optical shielding member as described in claim 1, wherein the main body of the frame is an opaque plate and is made of a metal material, wherein the metal material is aluminum or an aluminum alloy. An optical shield as described in claim 1, wherein the notch is a fan-shaped cross-sectional notch, a triangular cross-sectional notch, a rectangular cross-sectional notch, a polygonal cross-sectional notch or an irregular cross-sectional notch. An optical shielding member as described in claim 1, wherein the frame is a rectangular frame, and the main body of the frame includes a first side panel, a second side panel, a third side panel and a fourth side panel, wherein the first side panel is arranged opposite to the second side panel, the third side panel is arranged opposite to the fourth side panel, two ends of the third side panel are respectively connected to the first side panel and the second side panel, and two ends of the fourth side panel are respectively connected to the first side panel and the second side panel, wherein the first side panel, the second side panel, the third side panel and the fourth side panel surround to form the hollow portion. A projection display device comprises: A digital micro-mirror device comprising a substrate and a plurality of micro-reflective mirrors, wherein the plurality of micro-reflective mirrors are arranged in an array on the substrate to form a first area, wherein a second area is formed on a portion of the substrate where the micro-reflective mirrors are not arranged; A light-emitting unit is configured to project an incident light onto the digital micro-mirror device so that the plurality of micro-reflective mirrors in the first area of the digital micro-mirror device reflect the incident light to project an image; and An optical shielding member is disposed on the digital micromirror device and includes a frame and a coating layer, wherein the frame includes a body and a hollow portion, the body surrounds the hollow portion, wherein the body includes a first surface, a second surface, an inner surface and a notch, wherein the first surface and the second surface are two opposite surfaces of the body, the inner surface is connected to the first surface and corresponds to the hollow portion. The hollow portion is provided, wherein the second surface of the main body is attached to the digital microscope device, wherein the notch is formed by the inner surface being recessed in a direction away from the hollow portion, wherein the coating layer is provided on the first surface of the main body, wherein the roughness of the coating layer is less than 500 nanometers, the reflectivity of the coating layer to the incident light is less than 5%, and the transmittance of the coating layer to the incident light is less than 1%. A projection display device as described in claim 6, wherein the coating layer of the optical shielding element is a black coating layer. A projection display device as described in claim 6, wherein the main body is arranged corresponding to the second area of the digital microscope device, the hollow portion is arranged corresponding to the first area of the digital microscope device, and the area of the hollow portion of the optical shielding member is greater than or equal to the area of the first area of the digital microscope device. A projection display device as described in claim 6, wherein the main body of the frame is an opaque plate made of a metal material, wherein the metal material is aluminum or an aluminum alloy. A projection display device as described in claim 6, wherein the notch is a fan-shaped cross-sectional notch, a triangular cross-sectional notch, a rectangular cross-sectional notch, a polygonal cross-sectional notch or an irregular cross-sectional notch.

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