Projection apparatus and illumination system

An illumination system including a coherent light source device, a light delivery module, and a light wavelength conversion module is provided. The coherent light source device includes a light emitting source and a light collimating element. The light emitting source is adapted to emit at least one coherent light beam. The light collimating element is located on a transmission path of the at least one coherent light beam from the light emitting source and collimates the at least one coherent light beam. The light delivery module is located on a transmission path of at least one coherent light beam from the light collimating element and includes a first lens. The first lens has a lens array surface adapted to diverge any of the coherent light beam from the light collimating element. A projection apparatus is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 104128572, filed on Aug. 31, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

FIELD OF DISCLOSURE

The invention relates to an image apparatus and an optical system; more particularly, the invention relates to a projection apparatus and an illumination system.

DESCRIPTION OF RELATED ART

A laser projection apparatus generates a pure color light beam required for projection by utilizing a laser beam emitted by a laser diode to excite a fluorescent powder layer on a fluorescent wheel. To comply with the demands of the high-end market, the output brightness of the laser projection apparatus is repetitively required to be improved, and so is the laser power of the laser diode. However, given that the laser energy is enhanced and is overly concentrated on the fluorescent powder layer, the conversion efficiency of the fluorescent powder is reduced; thereby, the laser energy is left in form of heat on the fluorescent powder layer. As a result, the increase in the temperature of the fluorescent powder layer may lead to formation of burned marks on the fluorescent powder layer.

To resolve said issue, a diffusion film may be arranged on a transmission path of the laser beam to the fluorescent wheel according to the related art, so as to homogenize the energy through laser spot diffusion. However, the diffusion film itself may result in energy consumption. Besides, the diffusion direction of the diffusion film is isotropic. In the event that the long axis and the short axis of a light spot of the laser beam are both diffused by the diffusion film, the long axis of the laser spot generated on the fluorescent powder layer may be overly long, which causes the difficulty in optical coupling and the reduction of energy utilization efficiency.

SUMMARY

The invention provides a projection apparatus characterized by ideal output brightness and favorable energy utilization efficiency.

The invention is also directed to an illumination system capable of resolving issues resulting from the enhanced and overly concentrated coherent light beam energy.

Other objectives and advantages of the invention can be further illustrated by the technical features broadly embodied and described as follows.

In order to achieve at least one of the objects or other objects, an embodiment of the invention provides a projection apparatus that includes an illumination system, a light valve, and a projection lens. The illumination system includes a coherent light source device, a light delivery module, and a light wavelength conversion module is provided. The coherent light source device includes a light emitting source and a light collimating element. The light emitting source is adapted to emit at least one coherent light beam. The light collimating element is located on a transmission path of the at least one coherent light beam from the light emitting source and collimates the at least one coherent light beam. The light delivery module is located on a transmission path of the at least one coherent light beam from the light collimating element and includes a first lens. The first lens has a lens array surface. The lens array surface is adapted to diverge any of the at least one coherent light beam from the light collimating element. The light wavelength conversion module is arranged on the transmission path of the at least one coherent light beam from the light delivery module. The light wavelength conversion module is adapted to convert one portion of the at least one coherent light beam into a converted light beam. A wavelength of the converted light beam is different from a wavelength of the at least one coherent light beam, and the converted light beam and the other portion of the at least one coherent light beam constitute an illumination beam. The light valve is arranged on a transmission path of the illumination beam to convert the illumination beam into an image beam. The projection lens is located on a transmission path of the image beam.

In order to achieve at least one of the objects or other objects, an embodiment of the invention provides an illumination system that includes a coherent light source device, a light delivery module, and a light wavelength conversion module. The coherent light source device includes a light emitting source and a light collimating element. The light emitting source is adapted to emit at least one coherent light beam. The light collimating element is located on a transmission path of the at least one coherent light beam from the light emitting source and collimates the at least one coherent light beam. The light delivery module is located on a transmission path of the at least one coherent light beam from the light collimating element and includes a first lens. The first lens has a lens array surface. The lens array surface is adapted to diverge any of the at least one coherent light beam from the light collimating element. The light wavelength conversion module is arranged on the transmission path of the at least one coherent light beam from the light delivery module. The light wavelength conversion module is adapted to convert one portion of the at least one coherent light beam into a converted light beam. A wavelength of the converted light beam is different from a wavelength of the at least one coherent light beam.

In view of the above, the projection apparatus and the illumination system provided herein may achieve at least one of advantages or effects as listed below. The lens array surface of the first lens is able to diverge the coherent light beam and homogenize the energy; therefore, the illumination system provided herein may reduce the energy concentration of the coherent light beam on the light wavelength conversion module and further resolve the issue resulting from the enhanced and overly concentrated coherent light beam energy. Moreover, the illumination system provided herein does not require a diffusion film; accordingly, the conventional issues of energy loss, optical coupling difficulty, and reduction of energy utilization efficiency can be resolved, and the resultant projection apparatus may be characterized by ideal output brightness and favorable energy utilization efficiency.

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

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1Ais a schematic diagram illustrating a projection apparatus according to a first embodiment of the invention.FIG. 1Bis a schematic enlarged view illustrating the area A depicted inFIG. 1A.FIG. 1Cis a schematic enlarged view illustrating the first lens depicted inFIG. 1Aaccording to an embodiment of the invention.FIG. 1Dis a schematic front view illustrating a light wavelength conversion module depicted inFIG. 1A.FIG. 1Eis a schematic front view illustrating the coherent light source device depicted inFIG. 1A.FIG. 1Fis a schematic front view illustrating the lens array surface of the first lens depicted inFIG. 1A.

With reference toFIG. 1AtoFIG. 1F, a projection apparatus10includes an illumination system12, a light valve14, and a projection lens16. The illumination system12provides an illumination beam ILB. The light valve14is arranged on a transmission path of the illumination beam ILB to convert the illumination beam ILB into an image beam IMB. For instance, the light valve14may be a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel (LCOS panel), or any other appropriate spatial light modulator (SLM). The projection lens16is arranged on the transmission path of the image beam IMB and is capable of projecting the image beam IMB coming from the light valve14onto a screen, a wall, or any other object where images can be formed.

The illumination system12includes a coherent light source device100, a light delivery module200, and a light wavelength conversion module300. The coherent light source device100includes a light emitting source110and a light collimating element120. The light emitting source110is adapted to emit at least one coherent light beam B1. For instance, the light emitting source110may be a laser light emitting source, the coherent light beam B1may be a laser beam, and the color of the laser beam may be blue; however, the invention is not limited thereto. As shown inFIG. 1E, the light emitting source100provided in the embodiment may include a plurality of coherent light emitting elements112arranged in an array. The coherent light emitting elements112may be laser diodes, which should however not be construed as a limitation to the invention. Besides, the number of the coherent light emitting elements112may be adjusted according to the demand for the brightness of the projection apparatus10and should not be limited to that depicted inFIG. 1E.

The light collimating element120is located on a transmission path of the at least one coherent light beam B1from the light emitting source110and collimates the at least one coherent light beam B1coming from the coherent light emitting elements112. As shown inFIG. 1B, the coherent light beam B1emitted by each of the coherent light emitting elements112has a divergence angle θ1. For instance, the divergence angle θ1of a coherent light beam emitted by an exemplary laser diode may be approximately 20 degrees. The coherent light beam B1emitted by the coherent light emitting element112may be converged by the light collimating element120, such that the coherent light beam B1passing through the light collimating element120may be transmitted in a direction parallel to an optical axis O of the coherent light emitting element112. As a result, the coherent light beam B1may be collimated, and the issue of energy loss caused by the divergence of the coherent light beam B1may be resolved. As shown inFIG. 1E, the light collimating element120provided in the embodiment may include a plurality of collimating lenses122arranged in an array. In the embodiment, each collimating lens122corresponds to one coherent light emitting element112. Namely, the number of the coherent light emitting elements112is equal to the number of the collimating lenses122according to the embodiment.

The light delivery module200is located on a transmission path of the at least one coherent light beam B1from the light collimating element120and includes a first lens210. The first lens210has a lens array surface SLA. The lens array surface SLA is adapted to diverge any of the at least one coherent light beam B1from the light collimating element120. As shown inFIG. 1AandFIG. 1F, the lens array surface SLA includes a plurality of curved surfaces arranged in an array, for instance. Through the setting of parameters of the curved surfaces of the lens array surface SLA, e.g., the curvature of the curved surfaces, the value (positive or negative) of the curved surfaces, the number of the curved surfaces, the arrangement directions D1and D2of the curved surfaces, and the pitch of the curved surfaces in the arrangement directions D1and D2, the coherent light beam B1that passes any of the curved surface may have the divergence angle θ2greater than 0 degree but smaller than or equal to 4 degrees according to the embodiment. Moreover, in the embodiment, the arrangement directions D1and D2of the curved surfaces may be orthogonal to each other; however, the invention is not limited thereto.

In the embodiment, the coherent light beam B1is properly diverged; thereby, the conventional issues caused by the overly diverged coherent light beam B1(e.g., energy loss, optical coupling difficulty, and reduction of energy utilization efficiency) can be resolved, and energy can be homogenized. Besides, the setting of parameters of the curved surfaces of the lens array surface SLA may be adjusted according to the structure of the projection apparatus10in the embodiment, so as to optimize the energy and the shape of the light spot. The resultant projection apparatus10is thus characterized by ideal output brightness and favorable energy utilization efficiency.

According to the embodiment, the setting of parameters of the curved surfaces of the lens array surface SLA (e.g., the curvature of the curved surfaces, the value (positive or negative) of the curved surfaces, the number of the curved surfaces, the arrangement directions D1and D2of the curved surfaces, and the pitch of the curved surfaces in the arrangement directions D1and D2) may be adjusted in response to different demands. For instance, as shown inFIG. 1EandFIG. 1F, the arrangement directions D1and D2of the curved surfaces of the lens array surface SLA may be tilted at an angle θ3relative to the arrangement directions D3and D4of the coherent light emitting elements112(or the collimating lenses122). In the embodiment, the angle θ3ranges from 0 degree to 90 degrees. Practically, said tilted angle may be achieved by rotating the first lens210. In the embodiment, the arrangement directions D3and D4of the coherent light emitting elements112are orthogonal to each other; however, the invention is not limited thereto. As provided in the aforementioned design, the light spot of the coherent light beam B1formed on the light wavelength conversion module300may corresponds to the light homogenization element, which will be elaborated hereinafter.

In the embodiment, the curved surfaces of the lens array surface SLA and the collimating lenses122may not be correlated in a one-on-one manner. For instance, the number of the curved surfaces of the lens array surface SLA may be less than the number of the collimating lenses122, which should however not be construed as a limitation to the invention. In addition, the curved surfaces of the lens array surface SLA may be dented toward the inside of the first lens210, and the lens array surface SLA may be a surface of the first lens210facing the coherent light source device100; however, the invention is not limited thereto.

According to another embodiment, as shown inFIG. 2, the lens array surface SLA may also be a surface of the first lens210facing the light wavelength conversion module300(shown inFIG. 1A). Based on the design shown inFIG. 2, after the at least one coherent light beam B1passes through the first lens210, the coherent light beam B1is converged and then diverged. As such, energy homogenization may also be achieved.

The light wavelength conversion module300is arranged on the transmission path of the at least one coherent light beam B1from the light delivery module200. Besides, the light wavelength conversion module300is adapted to convert one portion of the coherent light beam B1into a converted light beam B2, and the other portion of the coherent light beam B1and the converted light beam B2may together constitute the illumination beam ILB. Here, the wavelength of the converted light beam B2is different from the wavelength of the coherent light beam B1. In the embodiment, the light wavelength conversion module300is a fluorescent wheel and may be a transmissive fluorescent wheel or a reflective fluorescent wheel, for instance; however, the invention is not limited thereto. The following descriptions are provided on the condition that the light wavelength conversion module300is the reflective fluorescent wheel.

As shown inFIG. 1D, in the embodiment, the light wavelength conversion module300may include a light transparent area R1and at least one wavelength conversion area R2; however, the invention is not limited thereto. With reference toFIG. 1AandFIG. 1D, in the embodiment, a fluorescent powder layer (not shown) may be arranged in the wavelength conversion area R2, so as to convert one portion of the coherent light beam B1into the converted light beam B2. For instance, a yellow fluorescent powder layer may be arranged in the wavelength conversion area R2, so as to convert the blue coherent light beam B1into the yellow converted light beam B2, which should not be construed as a limitation to the invention. In other embodiments, in order to increase the color variety of the illumination system12, other wavelength conversion areas may be further arranged in the light wavelength conversion module300, and different fluorescent powder layers in different colors may be arranged in different wavelength conversion areas, so as to form the converted light beam B2in multiple colors.

In the embodiment, the light wavelength conversion module300may further include a substrate plate (not shown) for holding the fluorescent powder layer. The substrate plate may be a light reflective plate or a light transmissive plate. In an embodiment of the invention, if the light wavelength conversion module300is equipped with the light reflective plate, the substrate plate may be made of metal, alloy, or a combination thereof, and the light transparent area R1may be formed by hollowing out the light reflective plate. In another embodiment of the invention, if the light wavelength conversion module300is equipped with the light transparent plate, the light wavelength conversion module300may further include a light reflective element (not shown) arranged on the wavelength conversion area R2, so as to reflect the converted light beam B2back to the light delivery module200. Here, the light reflective element is arranged between the fluorescent powder layer and the substrate plate.

According to the embodiment, when the light wavelength conversion module300rotates, the light transparent area R1and the wavelength conversion area R2may cut into the transmission path of the coherent light beam B1in turns. When the coherent light beam B1irradiates the light transparent area R1of the light wavelength conversion module300, the coherent light beam B1passes through the light transparent area R1. When the coherent light beam B1irradiates the wavelength conversion area R2, the wavelength conversion area R2converts the coherent light beam B1into a converted light beam B2. Before the coherent light beam B1is transmitted to the wavelength conversion area R2, the coherent light beam B1has passed through the lens array surface SLA, and the energy has been homogenized. Hence, the energy concentration of the coherent light beam B1on the light wavelength conversion module300can be reduced, and the aforesaid issues resulting from the enhanced and overly concentrated energy (such as the reduced conversion efficiency of the fluorescent powder layer, the increase in the temperature of the fluorescent powder layer, and the formation of burned marks) can be resolved.

In the embodiment, the light delivery module200may further include a light combination element220. As shown inFIG. 1A, in the embodiment, the light combination element220is arranged between the coherent light source device100and the light wavelength conversion module300, and the first lens210can be arranged between the coherent light source device100and the light combination element220, which should however not be construed as limitations to the invention. In another embodiment, the first lens210may also be arranged between the light combination element220and the light wavelength conversion module300(which will be elaborated hereinafter).

Besides, according to the embodiment, the light delivery module200may further include a second lens230, a third lens240, and a fourth lens250sequentially arranged from the coherent light source device100to the light wavelength conversion module300, wherein the first lens210is arranged between the second lens230and the third lens240, and the light combination element220is arranged between the first lens210and the third lens240. Refractive powers of the second lens230, the first lens210, the third lens240, and the fourth lens250are sequentially positive, negative, positive, and positive. From another perspective, in the embodiment, the second lens230has a convex surface facing the coherent light source device100, the first lens210is a biconcave lens with the lens array surface SLA, the third lens240has a convex surface facing the coherent light source device100, and the fourth lens250has a convex surface facing the coherent light source device100, for instance.

The coherent light beam B1coming from the coherent light source device100is transmitted to the light wavelength conversion module300sequentially through the light collimating element120, the second lens230, the first lens210, the light combination element220, the third lens240, and the fourth lens250. When the wavelength conversion area R2cuts into the transmission path of the coherent light beam B1, the wavelength conversion area R2converts the coherent light beam B1into the converted light beam B2and reflects the converted light beam B2, and the reflected converted light beam B2returns to the light combination element220sequentially through the fourth lens250and the third lens240. On the other hand, when the light transparent area R1of the light wavelength conversion module300cuts into the transmission path of the coherent light beam B1, the coherent light beam B1passes through the light transparent area R1, is sequentially reflected by reflective mirrors M1, M2, and M3in the illumination system12, and then is directed to the light combination element220. The light combination element220combines the coherent light beam B1coming from the reflective mirror M3with the converted light beam B2coming from the third lens240to generate the illumination beam ILB and transmits the illumination beam ILB toward the light valve14.

However, in response to different demands, the illumination system12may further include other elements. For instance, the illumination system12may further include a light homogenization element400. The light homogenization element400is arranged on the transmission path of the illumination beam ILB from the light combination element220, so as to further homogenize the illumination beam ILB. The light homogenization element400may be a light integration rod or a lens array. In order for the light spot of the coherent light beam B1formed on the light wavelength conversion module300to correspond to the light homogenization element400, as shown inFIG. 1A,FIG. 1E, andFIG. 1F, the arrangement directions D1and D2of the curved surfaces of the lens array surface SLA may be tilted at an angle θ3relative to arrangement directions D3and D4of the coherent light emitting elements112(or the collimating lenses122), so as to properly adjust the size of the light spot on the light wavelength conversion module300in response to the design demands of various laser spots. Moreover, the illumination system12may further include a plurality of light converging elements500,600,700, and800, e.g., light converging lenses. In the embodiment, the light converging elements500and600are arranged between the light combination element220and the light homogenization element400, so as to converge the illumination beam ILB coming from the light combination element220into the light homogenization element400. The light converging elements700and800are arranged between the light homogenization element400and the light valve14, so as to transmit the illumination beam ILB coming from the light homogenization element400to the light valve14.

FIG. 3andFIG. 6are schematic views illustrating a projection apparatus according to a second embodiment to a fifth embodiment of the invention. With reference toFIG. 3toFIG. 6, the projection apparatuses10A,10B,10C, and10D are similar to the projection apparatus10, and the same or similar elements are represented by the same or similar reference numbers. Therefore, no further descriptions are provided herein. The difference among the projection apparatuses10,10A,10B,10C, and10D lies in the design of the light delivery modules200,200A,200B,200C, and200D in the illumination systems12,12A,12B,12C, and12D.

To be specific, as shown inFIG. 3, in the light delivery module200A, the first lens21OA is arranged between the coherent light source device100and the second lens230A. The refractive powers of the first lens210A, the second lens230A, the third lens240A, and the fourth lens250A are sequentially positive, negative, positive, and positive. From another perspective, in the embodiment, the first lens210A has a convex surface facing the coherent light source device100and has the lens array surface SLA facing the light wavelength conversion module300, the second lens230A has a concave surface facing the light wavelength conversion module300, the third lens240A has a convex surface facing the coherent light source device100, and the fourth lens250A has a convex surface facing the coherent light source device100, for instance. Under such design, the coherent light beam B1coming from the coherent light source device100is transmitted to the light wavelength conversion module300sequentially through the light collimating element120, the first lens210A, the second lens230A, the light combination element220, the third lens240A, and the fourth lens250A. Besides, the converted light beam B2reflected by the light wavelength conversion module300returns to the light combination element220after sequentially passing through the fourth lens250A and the third lens240A. According to the embodiment as shown inFIG. 3, the lens array surface SLA may also be a surface of the first lens210A facing the light wavelength conversion module300, which should however not be construed as a limitation to the invention. According to another embodiment, the lens array surface SLA may be a surface of the first lens210A facing the coherent light source device100.

As shown inFIG. 4, in the light delivery module200B, the first lens210B is arranged between the third lens240B and the fourth lens250B. The refractive powers of the second lens230A, the third lens240B, the first lens210B, and the fourth lens250B are sequentially positive, negative, positive, and positive. From another perspective, in the embodiment, the second lens230B has a convex surface facing the coherent light source device100, the third lens240B has a concave surface facing the light wavelength conversion module300, the first lens210B has the lens array surface SLA facing the light wavelength conversion module300and a convex surface facing the coherent light source device100, and the fourth lens250B has a convex surface facing the coherent light source device100, for instance. Under such design, the coherent light beam B1coming from the coherent light source device100is transmitted to the light wavelength conversion module300sequentially through the collimating element120, the second lens230B, the third lens240B, the light combination element220, the first lens210B, and the fourth lens250B. Besides, the converted light beam B2reflected by the light wavelength conversion module300returns to the light combination element220after sequentially passing through the fourth lens250B and the first lens210B. According to the embodiment as shown inFIG. 4, the lens array surface SLA may be a surface of the first lens210B facing the light wavelength conversion module300, which should however not be construed as a limitation to the invention. According to another embodiment, the lens array surface SLA may be a surface of the first lens210B facing the coherent light source device100.

As shown inFIG. 5, in the light delivery module200C, the first lens210C is arranged between the fourth lens250C and the light wavelength conversion module300. The refractive powers of the second lens230C, the third lens240C, the fourth lens250C, and the first lens210C are sequentially positive, negative, positive, and positive. From another perspective, in the embodiment, the second lens230C has a convex surface facing the coherent light source device100, the third lens240C has a concave surface facing the light wavelength conversion module300, the fourth lens250C has a convex surface facing the coherent light source device100, and the first lens210C has the lens array surface SLA facing the light wavelength conversion module300and a convex surface facing the coherent light source device100, for instance. Under such design, the coherent light beam B1coming from the coherent light source device100is transmitted to the light wavelength conversion module300sequentially through the collimating element120, the second lens230C, the third lens240C, the light combination element220, the fourth lens250C, and the first lens210C. Besides, the converted light beam B2reflected by the light wavelength conversion module300returns to the light combination element220after sequentially passing through the first lens210C and the fourth lens250C. According to the embodiment as shown inFIG. 5, the lens array surface SLA may be a surface of the first lens210C facing the light wavelength conversion module300, which should however not be construed as a limitation to the invention. According to another embodiment, the lens array surface SLA may be a surface of the first lens210C facing the coherent light source device100.

As shown inFIG. 6, in the light delivery module200D, the light delivery module200D further includes a second lens230D, a third lens240D, a fourth lens250D, and a fifth lens260D sequentially arranged from the coherent light source device100to the light wavelength conversion module300. The refractive powers of the second lens230D, the third lens240D, the fourth lens250D, and the fifth lens260D are sequentially positive, negative, positive, and positive. From another perspective, in the embodiment, the second lens230D has a convex surface facing the coherent light source device100, the third lens240D has a concave surface facing the light wavelength conversion module300, the fourth lens250D has a convex surface facing the coherent light source device100, and the fifth lens260D has a convex surface facing the coherent light source device100, for instance. According to the embodiment as shown inFIG. 6, the lens array surface SLA may be a surface of the first lens210D facing the light wavelength conversion module300, which should however not be construed as a limitation to the invention. According to another embodiment, the lens array surface SLA may be a surface of the first lens210D facing the coherent light source device100. Additionally, according to the embodiment, the first lens210D is arranged between the third lens240D and the fourth lens250D and between the third lens240D and the light combination element220, which should however not be construed as limitations to the invention. In another embodiment, the first lens210D may also be arranged between the coherent light source device100and the second lens230D. In another embodiment, the first lens210D may also be arranged between the second lens230D and the third lens240D. In another embodiment, the first lens210D may also be arranged between the light combination element220and the fourth lens250D. In still another embodiment, the first lens210D may also be arranged between the fourth lens250D and the fifth lens260D. In another embodiment, the first lens210D may also be arranged between the fifth lens260D and the light wavelength conversion module300.

To sum up, the projection apparatus and the illumination system provided in several embodiments of the invention may achieve at least one of advantages or effects as listed below. The lens array surface of the first lens may diverge the coherent light beam and homogenize the energy; therefore, the illumination system provided herein may reduce the energy concentration of the coherent light beam on the light wavelength conversion module. Moreover, the illumination system provided herein does not require a diffusion film; accordingly, the conventional issues of energy loss, optical coupling difficulty, and reduction of energy utilization efficiency can be resolved, and the resultant projection apparatus may be characterized by ideal output brightness and favorable energy utilization efficiency.