Patent Description:
The invention relates to an optical device, particularly to a projection device.

The light source device required by a three-color-combined light projector that uses a light valve system of a digital light processor (DLP) or Liquid Crystal on Silicon (LCoS) has a complex optical system, which results in its huge volume. The advantage of using a three-chip micro-LED display panel with a light-combining system is that the size of the projection device may be reduced.

However, the greatest problem of using the three-chip micro-LED display panel with the light-combining system is the large light-emitting angle of the micro-LED. The method of reducing this angle is to add a reflective cover and to use a micro-LED array (that is, a micro-optical array), but the light-emitting half-angle can only be reduced by <NUM> degrees (under the condition of a pixel size of less than <NUM>). Moreover, as the light-emitting angle to be reduced is restricted, due to the large light-emitting half-angle and the total reflection inside the light-combining system (light greater than the effective light angle is only totally reflected inside the light-combining module), ineffective light is therefore introduced into the projection lens, leaving stray light appearing on the projected image, which affects the contrast of the projected image.

<CIT> describes a projection display which includes an illumination module, an optical modulator for modulating light incident from the illumination module in response to image data, and a projection optical system for projecting light emitted from the optical modulator on an enlarged scale. The illumination module includes at least one light source, and a light recycling unit which causes light emitted from the light source having an emission angle beyond a predetermined range in which light can be effectively projected by the projection optical system to travel within the predetermined range. <CIT> describes a controllable light angle selecting device. It comprises a fixed light selecting means adapted to transmit light incident thereon within a limited acceptance angle, optically connected to at least one light redirecting means capable of obtaining a variable angular difference between light entering said light redirecting means and light exiting said light redirecting means. <CIT> describes an illumination part which comprises luminous element arrays, side optical source sections, indicate panel parts and a color combination part. The third luminous element array generates the light of the different wavelength to score the first. The third side optical source section changes to the surface light source. The third indicate panel part changes into the third optical signal to score the light of the third side optical source section according to the presentation image. <CIT> describes a projector which includes: the illuminating device; an electro-optical modulator on which an illuminating luminous flux emitted from the illuminating device is made incident on and which modulates it according to image information; and a projecting lens. The projector includes as the illuminating device: a light source device that emits an illuminating luminous flux to an area to be illuminated; and a rectangular prism which transmits the illuminating luminous flux and rotates so that a light emission area and a light non-emission area are alternately scrolled on the electro-optical modulator in succession in synchronization with the screen writing frequency of the electro-optical modulator. <CIT> describes a composite optical element. The composite optical element includes a plurality of optical elements, in which at least one of the optical elements is formed of an element modifying an optical path and the other optical elements are bonded to an incident surface and/or exit surface of the element modifying the optical path with a low refractive index material layer in between. 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.

It is an object of the invention to provide a projection device capable of effectively reducing stray light from transmitting out of the projection device through a light-combining module, and increasing the contrast of the projected image.

An embodiment of the present invention provides a projection device, which includes a first display, a second display, a third display, a light-combining module, a first angle selector, a second angle selector, a third angle selector, and a projection lens. The first display, the second display, and the third display are respectively adapted to provide a first image beam, a second image beam, and a third image beam. The light-combining module has a first light-incident surface, a second light-incident surface, a third light-incident surface, and a light-outgoing surface. The first angle selector is configured between the first display and the light-combining module. The second angle selector is configured between the second display and the light-combining module. The third angle selector is configured between the third display and the light-combining module. The projection lens is configured on one side of the light-outgoing surface of the light-combining module, and is adapted to project the first image beam, the second image beam, and the third image beam out of the projection device. The first image beam, the second image beam, and the third image beam respectively pass through the first angle selector, the second angle selector, and the third angle selector, and are then transmitted to the projection lens by the light-combining module.

In one or more embodiments, the first light-incident surface may be opposite to the third light-incident surface.

The second light-incident surface may be opposite to the light-outgoing surface.

The second light-incident surface may be connected between the first light-incident surface and the third light-incident surface.

In one or more embodiments, the first angle selector may be a red-light wavelength filter.

In one or more embodiments, the first angle selector may allow the first image beam having an incident angle of less than <NUM> degrees to pass, and reflects the first image beam having an incident angle of <NUM> degrees or more.

In one or more embodiments, the second angle selector may be a green-light wavelength filter.

In one or more embodiments, the second angle selector may allow the second image beam having an incident angle of less than <NUM> degrees to pass, and reflects the second image beam having an incident angle of <NUM> degrees or more.

In one or more embodiments, the third angle selector may be a blue-light wavelength filter.

In one or more embodiments, the third angle selector may allow the third image beam having an incident angle of less than <NUM> degrees to pass, and reflects the third image beam having an incident angle of <NUM> degrees or more.

In one or more embodiments, the projection device further comprises a first anti-reflection layer, a second anti-reflection layer, and a third anti-reflection layer.

In one or more embodiments, the first anti-reflection layer, the second anti-reflection layer, and the third anti-reflection layer are respectively disposed on the first light-incident surface, the second light-incident surface, and the third light-incident surface.

In one or more embodiments, the light-combining module may reflect the first image beam to the projection lens, may allow the second image beam to pass and be transmitted to the projection lens, and may reflect the third image beam to the projection lens.

In one or more embodiments, the projection device may further comprise a fourth anti-reflection layer.

In one or more embodiments, the fourth anti-reflection layer may be disposed on the light-outgoing surface of the light-combining module.

In one or more embodiments, the light-combining module may be a light-combining prism.

In one or more embodiments, the first display, the second display, and the third display may be micro-light-emitting-diode display panels.

Based on the above, in an embodiment of the present invention, since the projection device is provided with the first angle selector, the second angle selector, and the third angle selector, stray light of the projection device may be reduced effectively, so that the projected image has higher contrast.

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 present invention. In <FIG>, an embodiment of the present invention provides a projection device <NUM>, including a first display <NUM>, a second display <NUM>, a third display <NUM>, a light-combining module <NUM>, a first angle selector <NUM>, a second angle selector <NUM>, a third angle selector <NUM>, and a projection lens <NUM>.

In this embodiment, the first display <NUM>, the second display <NUM>, and the third display <NUM> may be a liquid crystal display panel, a LED display panel, a mini LED display panel, or a micro-LED display panel, but the present invention is not limited thereto.

In this embodiment, the light-combining module <NUM> is, for example, a light-combining prism (X-Cube) formed by bonding four prisms, and the refractive index of the bonding agent is preferably the same as that of the prisms, but the manufacturing method described above is not limited to the manufacturing method of the light-combining module <NUM>. In the above configuration, every two adjacent prism surfaces may be provided with an optical film (for example, provide the film by coating), so that the beam with a specific wavelength in the image beam that is transmitted to the prism surface is reflected, whereas the image beams in the rest of the wavelength ranges pass through the prism surface.

In this embodiment, the first angle selector <NUM>, the second angle selector <NUM>, and the third angle selector <NUM> may be optical films formed by stacking high and low refractive indexes.

In this embodiment, the projection lens <NUM> includes, for example, a combination of one or more optical lenses with diopter. Optical lenses include various combinations of non-planar lenses, such as biconcave lenses, biconvex lenses, meniscus lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. The present invention does not limit the form and type of the projection lens <NUM>.

Specifically, the first display <NUM>, the second display <NUM>, and the third display <NUM> of this embodiment are adapted to provide a first image beam R, a second image beam G, and a third image beam B, respectively. The first image beam R is, for example, a red light image beam; the second image beam G is, for example, a green light image beam; and the third image beam B is, for example, a blue light image beam. However, the invention is not limited thereto.

In this embodiment, the light-combining module <NUM> has a first light-incident surface <NUM>, a second light-incident surface <NUM>, a third light-incident surface <NUM>, and a light-outgoing surface <NUM>. The first light-incident surface <NUM> is opposite to the third light-incident surface <NUM>, the second light-incident surface <NUM> is opposite to the light-outgoing surface <NUM>, and the second light-incident surface <NUM> is connected between the first light-incident surface <NUM> and the third light-incident surface <NUM>. The first angle selector <NUM> is disposed between the first display <NUM> and the light-combining module <NUM>. The second angle selector <NUM> is disposed between the second display <NUM> and the light-combining module <NUM>. The third angle selector <NUM> is disposed between the third display <NUM> and the light-combining module <NUM>. The first angle selector <NUM>, the second angle selector <NUM>, and the third angle selector <NUM> are respectively disposed on one side of the first light-incident surface <NUM>, the second light-incident surface <NUM>, and the third light-incident surface <NUM> of the light-combining module <NUM>.

In this embodiment, the first image beam R, the second image beam G, and the third image beam B respectively pass through the first angle selector <NUM>, the second angle selector <NUM>, and the third angle selector <NUM>, and then are transmitted to the projection lens <NUM> as light combined by the light-combining module <NUM>. The projection lens <NUM> is disposed on one side of the light-outgoing surface <NUM> of the light-combining module <NUM> and is adapted to project the first image beam R, the second image beam G, and the third image beam B out of the projection device <NUM>. The first image beam R is reflected to the projection lens <NUM> by the optical film of the light-combining module <NUM> that has the function of reflecting the red-light waveband, the second image beam G passes through the light-combining module <NUM> and transmits to the projection lens <NUM>, and the third image beam B is reflected to the projection lens <NUM> by the optical film of the light-combining module <NUM> that has the function of reflecting the blue-light waveband. The two optical films above are configured in X-type.

In this embodiment, the first angle selector <NUM> is a filter (band pass filter), such as a red-light wavelength filter. For example, when light is incident perpendicularly to the first angle selector <NUM>, the light of a wavelength falling within the range of <NUM> to <NUM> is transmitted to pass through it whereas the light of the rest of the wavelengths is reflected. Moreover, the first angle selector <NUM> transmits light whose incident angle is less than <NUM> degrees (<<NUM>°) to pass through it and reflects light whose incident angle is <NUM> degrees or more (≧ <NUM><NUM>).

In this embodiment, the second angle selector <NUM> is a filter, such as a green-light wavelength filter. For example, when light is incident perpendicularly to the second angle selector <NUM>, the light of a wavelength falling within the range of <NUM> to <NUM> is transmitted to pass through it and the light of the rest of the wavelengths is reflected. Moreover, the second angle selector <NUM> transmits light whose incident angle is less than <NUM> degrees (<<NUM>°) to pass through it and reflects light whose incident angle is <NUM> degrees or more (≧ <NUM><NUM>).

In this embodiment, the third angle selector <NUM> is a filter, such as a blue-light wavelength filter. For example, when light is incident perpendicularly to the third angle selector <NUM>, the light of a wavelength falling within the range of <NUM> to <NUM> is transmitted to pass through it and the light of the rest of the wavelengths is reflected, or, for example, the light whose wavelength is less than or equal to <NUM> is transmitted to pass through it and the light of the rest of the wavelengths is reflected. Moreover, the third angle selector <NUM> transmits light whose incident angle is less than <NUM> degrees (<<NUM>°) to pass through it and reflects light whose incident angle is <NUM> degrees or more (≧ <NUM><NUM>).

In this embodiment, the projection device <NUM> further includes a first anti-reflection layer <NUM>, a second anti-reflection layer <NUM>, and a third anti-reflection layer <NUM>. The first anti-reflection layer <NUM>, the second anti-reflection layer <NUM>, and the third anti-reflection layer <NUM> are respectively disposed on the first light-incident surface <NUM>, the second light-incident surface <NUM>, and the third light-incident surface <NUM>.

In this embodiment, the projection device <NUM> further includes a fourth anti-reflection layer <NUM>, and the fourth anti-reflection layer <NUM> is disposed on the light-outgoing surface <NUM>. Since the projection device <NUM> is provided with the first anti-reflection layer <NUM>, the second anti-reflection layer <NUM>, the third anti-reflection layer <NUM>, and the fourth anti-reflection layer <NUM>, the light-outgoing efficiency of the projection device <NUM> of the embodiment of the present invention is improved effectively.

<FIG> is a schematic diagram of stray light in a projected image of a projection device provided with a third angle selector according to an embodiment of the present invention. In <FIG>, the left image shows the stray light formed at the light-outgoing surface of the light-combining module <NUM>, and the right image shows the stray light formed by the light emerging from the projection lens <NUM>. In <FIG>, in the effective projected image, the stray light is reduced by <NUM>%, and the stray light outside the effective projected image is only about <NUM>%.

Based on the above, in an embodiment of the present invention, since the projection device <NUM> is provided with: the first angle selector <NUM> located between the first display <NUM> and the light-combining module <NUM>, the second angle selector <NUM> located between the second display <NUM> and the light-combining module <NUM>, and the third angle selector <NUM> located between the third display <NUM> and the light-combining module <NUM>, thus large-angle image light that is more likely to have total internal reflection in the light-combining module <NUM> is reflected by the first angle selector <NUM>, the second angle selector <NUM>, and the third angle selector <NUM> and does not enter the light-combining module <NUM>. As the incident angle of the image beam incident to the light-combining module <NUM> is restricted effectively, the stray light of the projection device <NUM> is reduced, thereby improving the contrast of the projected image.

<FIG> is a schematic diagram of a projection device according to another embodiment of the present invention. In <FIG>, the projection device <NUM>' of <FIG> is similar to the projection device <NUM> of <FIG>, and their main differences are that: in the projection device <NUM>' of <FIG>, a first angle selector <NUM>, a second angle selector <NUM>, and a third angle selector <NUM> are respectively (and directly) configured on a first light-incident surface <NUM>, a second light-incident surface <NUM>, and a third light-incident surface <NUM>, and therefore, the overall volume of the projection device <NUM>' is reduced. A light-outgoing surface <NUM> of a light-combining module <NUM> of the projection device <NUM>' has a fourth anti-reflection layer <NUM>, so that the light-outgoing efficiency of the projection device <NUM>' of the embodiment of the present invention is improved effectively.

In summary, in an embodiment of the present invention, since the projection device is provided with a first angle selector located between the first display and the light-combining module, a second angle selector located between the second display and the light-combining module, and a third angle selector located between the third display and the light-combining module, the stray light of the projection device is reduced effectively, and the contrast of the projected image is higher.

Claim 1:
A projection device (<NUM>), comprising a first display (<NUM>), a second display (<NUM>), a third display (<NUM>), a light-combining module (<NUM>), a first angle selector (<NUM>), a second angle selector (<NUM>), a third angle selector (<NUM>), and a projection lens (<NUM>), wherein:
the first display (<NUM>), the second display (<NUM>), and the third display (<NUM>) are respectively adapted to provide a first image beam (R), a second image beam (G), and a third image beam (B);
the light-combining module (<NUM>) comprises a first light-incident surface (<NUM>), a second light-incident surface (<NUM>), a third light-incident surface (<NUM>), and a light-outgoing surface (<NUM>);
the first angle selector (<NUM>) is provided between the first display (<NUM>) and the light-combining module (<NUM>), the second angle selector (<NUM>) is provided between the second display (<NUM>) and the light-combining module (<NUM>), and the third angle selector (<NUM>) is provided between the third display (<NUM>) and the light-combining module (<NUM>); and
the projection lens (<NUM>) is provided on one side of the light-outgoing surface (<NUM>) of the light-combining module (<NUM>), and the projection lens (<NUM>) is adapted to project the first image beam (R), the second image beam (G), and the third image beam (B) out of the projection device (<NUM>), wherein:
after the first image beam (R), the second image beam (G), and the third image beam (B) have passed through the first angle selector (<NUM>), the second angle selector (<NUM>), and the third angle selector (<NUM>) respectively, the first image beam (R), the second image beam (G), and the third image beam (B) are transmitted to the projection lens (<NUM>) by the light-combining module (<NUM>),
the projection device (<NUM>) further comprises a first anti-reflection layer (<NUM>), a second anti-reflection layer (<NUM>), and a third anti-reflection layer (<NUM>), wherein the first anti-reflection layer (<NUM>), the second anti-reflection layer (<NUM>), and the third anti-reflection layer (<NUM>) are respectively disposed on the first light-incident surface (<NUM>), the second light-incident surface (<NUM>), and the third light-incident surface (<NUM>) of the light-combining module (<NUM>).