Patent Description:
At present, most light source devices use laser light to excite fluorescent powder to generate a white light source, which has high stability and low cost. However, the excitation efficiency of the fluorescent powder is related to power and power density of the exciting light and the temperature of the fluorescent powder. Thus, when the exciting light is converged on a surface of the fluorescent powder, the fluorescent powder has low excitation efficiency due to the relatively high energy density of the exciting light, while most of light energy that is not converted by the fluorescent powder propagates in a form of heat, so that the temperature of the fluorescent powder in a region irradiated by a light spot of the exciting light is increased, thereby further reducing the excitation efficiency of the fluorescent powder.

Conventional light source devices are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

In view of the above, it is urgent to provide a light source device and a projection system with high efficiency.

An exemplary light source device includes an exciting light source for generating exciting light, a light condensing device, and a fluorescent cavity. The fluorescent cavity comprises a chamber and a fluorescent layer, wherein the chamber has a light window allowing light to enter and exit and a bottom wall opposite to the light window, and the fluorescent layer is provided on a surface of the bottom wall and on a path of light converged by the light condensing device. The exciting light is converged by the light condensing device, then incident to a surface of the fluorescent layer from the light window to form a light spot and excite the fluorescent layer to generate excited light, wherein an area of the light window is smaller than an area of the light spot, and the excited light is emitted from the light window.

A projection system includes the light source device described above.

The light source device provided by the present disclosure includes the chamber with the light window. During the exciting light being incident to the fluorescent cavity, the energy of the exciting light does not change, and the area of the light spot of the fluorescent layer is increased with respect to the area of the light window of the fluorescent cavity. In this way, when the fluorescent layer is excited by the exciting light to generate excited light, the power density of the exciting light is decreased, and the excitation efficiency is increased.

The technical solutions in the embodiments of the present disclosure will be clearly and thoroughly described below with reference to the drawings in the embodiments of the present disclosure. It should be understood that, the described embodiments are only a part of, but not all of the embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present disclosure.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this present disclosure belongs. The term "or/and" as used herein includes any one of and all combinations of the associated listed items.

The light source device of the present disclosure can be applied to products such as projectors, laser televisions, and cinema projectors.

<FIG> is a structural schematic diagram of a light source device according to an Embodiment <NUM> of the present disclosure. Referring to <FIG>, the light source device <NUM> includes an exciting light source <NUM>, a light homogenizing element <NUM>, a light splitting element <NUM>, a light condensing device <NUM>, and a fluorescent cavity <NUM>. The exciting light source <NUM> is configured to generate exciting light. The exciting light is incident to the fluorescent cavity <NUM> after sequentially passing through the light homogenizing element <NUM>, the light splitting element <NUM>, and the light condensing device <NUM>. Fluorescent substance in the fluorescent cavity <NUM> is excited by the exciting light to generate excited light. The excited light is emitted from the fluorescent cavity <NUM>, passes through the light condensing device <NUM>, and is finally transmitted from the light splitting element <NUM>.

The exciting light source <NUM> configured to emit exciting light may be a semiconductor diode or a semiconductor diode array, such as a laser diode (LD) or a light emitting diode (LED). The exciting light may be blue light, purple light, or ultraviolet light, but it is not limited to the above. In the present embodiment, the exciting light generated by the exciting light source <NUM> is blue exciting light of <NUM>.

The light homogenizing element <NUM> is located on an optical path of the exciting light generated by the exciting light source <NUM>, and configured to perform light homogenizing treatment on the exciting light, in order to provide the homogenized exciting light to be processed and used by the subsequent light splitting element <NUM>, light condensing device <NUM>, and the like.

The light splitting element <NUM> is located on an optical path of the exciting light emitted from the light homogenizing element <NUM>, and it is capable of reflecting at least a part of the exciting light that reaches a surface of the light splitting element <NUM>. In the present embodiment, the light splitting element <NUM> is a blue light splitting lens. The blue light splitting lens can reflect the blue exciting light.

The light condensing device <NUM> is located on an optical path of the exciting light reflected by the light splitting element <NUM>. The light condensing device <NUM> is configured to converge the exciting light reflected by the light splitting element <NUM>, and the exciting light converged by the light condensing device <NUM> is incident to the fluorescent cavity <NUM>. Preferably, the light condensing device <NUM> can focus the exciting light irradiated thereon and form a focus. The light condensing device <NUM> is assembled by a plurality of lenses. In the present embodiment, the light condensing device <NUM> is composed of three lenses. Without doubt, in other embodiments, the number of lenses in the light condensing device <NUM> may be others, which is not limited in the present disclosure.

The fluorescent cavity <NUM> includes a casing <NUM>, a chamber <NUM>, and a fluorescent layer <NUM>. The chamber <NUM> is formed inside the casing <NUM>. The fluorescent layer <NUM> is disposed in the chamber <NUM>.

The chamber <NUM> has a light window <NUM>, a bottom wall <NUM>, and side walls <NUM>. The light window <NUM> is arranged opposite to the bottom wall <NUM>. The side walls <NUM> are disposed between the light window <NUM> and the bottom wall <NUM> and connects the light window <NUM> with the bottom wall <NUM>. In the present embodiment, the bottom wall <NUM> has a larger area than the light window <NUM>, and a shape of the chamber <NUM> is substantially a cone shape. Referring to <FIG> in combination, in other alternative embodiments, the chamber <NUM> may also have a pyramid shape, a spherical shape, an ellipsoid shape, a cylindrical shape, or a prism shape, which is not limited in the present disclosure.

The light window <NUM> is located on top of the casing <NUM>. Without doubt, the light window <NUM> is also located on the top of the chamber <NUM>. The light window <NUM> serves as an entrance and exit through which the light enters and exits from the chamber <NUM>. In the present embodiment, the light window <NUM> has a circular shape. Without doubt, in an alternative embodiment, the light window <NUM> may also be square, rectangular, or oval, which is not limited in the present disclosure.

Specifically, the exciting light is incident into the chamber <NUM> through the light window <NUM> after being converged by the light condensing device. All the excited light is emitted from the chamber <NUM> through the light window <NUM>. In the present embodiment, a plane where the light window <NUM> is located is perpendicular to the direction of the exciting light reflected by the light splitting element <NUM>. The light window <NUM> is near the focus of the exciting light converged by the light condensing device <NUM>. In the present embodiment, the focus is located in the light window <NUM>. Further, the focus is exactly located at a center of the light window <NUM>.

The bottom wall <NUM> is located at a bottom of the chamber <NUM>. The bottom wall <NUM> is arranged opposite to the light window <NUM>. In the present embodiment, the area of the bottom wall <NUM> is obviously larger than the area of the light window <NUM>.

The side wall <NUM> includes a reflective layer (not shown). The reflective layer is disposed on a surface of the side wall <NUM>. The reflective layer is configured to reflect the excited light, such that the excited light can be emitted from the light window <NUM>; or, it is configured to reflect the excited light one or more times, such that the light can reach the fluorescent layer <NUM> again and excite the fluorescent layer <NUM> again to generate excited light.

The fluorescent layer <NUM> is disposed on a surface of the bottom wall <NUM>. The fluorescent layer <NUM> is excited by the exciting light irradiated to the surface thereof and generates the excited light. The fluorescent layer <NUM> is also arranged opposite to the light window <NUM>. The exciting light enters the chamber through the light window <NUM> and is directly irradiated to the surface of the fluorescent layer <NUM> to excite the fluorescent layer <NUM> and generate excited light. It can be understood that the area of the fluorescent layer <NUM> may be the same as that of the bottom wall <NUM> or smaller than that of the bottom wall <NUM>. The excited light reaches the fluorescent layer <NUM> and generates a light spot after passing through the light window <NUM>. It can be understood that the area of the light spot is much larger than the area of the focus. In addition, the light spot is located in a range of the fluorescent layer <NUM>. Preferably, the area of the fluorescent layer <NUM> is the same as the area of the bottom wall <NUM>.

In order to explain a light emitting principle of the light source device <NUM>, a light emitting process of the light source device <NUM> is generally described below.

At first, the exciting light is generated by the exciting light source <NUM>. The exciting light sequentially passes through the light homogenizing element <NUM>, the light splitting element <NUM>, and the light condensing device <NUM> and is finally incident to the chamber <NUM>.

The exciting light passes through the light condensing device <NUM> and is converged and focused to form the focus. The focus may be located near the light window <NUM> or located just in the light window <NUM>. In other words, the light window <NUM> may be located near above or below the focus, so that the exciting light is incident to the chamber <NUM> as much as possible.

It can be understood that as the light travels in a straight line, the exciting light may diffuse when passing through the light window <NUM> and incident on the fluorescent layer <NUM>, and thus the light spot formed on the fluorescent layer <NUM> may be larger than a cross section of the exciting light incident in the light window. The area of the fluorescent layer <NUM> is larger than the area of the light spot, and thus the light spot is completely located within the range of the fluorescent layer <NUM>. In other words, the light window <NUM> is relatively close to the focus, and the fluorescent layer <NUM> is relatively far from the focus, such that the area of the light spot formed on the fluorescent layer <NUM> is larger than the cross-sectional area of the exciting light incident at the light window <NUM>.

After the exciting light is irradiated to the fluorescent layer <NUM>, the fluorescent layer <NUM> generates excited light, and the excited light is reflected in a form of Lambertian light. In the chamber <NUM>, the excited light in small-angle is directly emitted from the light window <NUM> of the chamber <NUM> at a small angle; the excited light in large-angle is reflected by the side walls <NUM> and the bottom wall <NUM> one or more times and is finally emitted from the light window <NUM> at a small angle. In other words, all the excited light is emitted from the light window <NUM> at a small angle, thereby increasing a collection efficiency of the light condensing device <NUM>. In other words, the fluorescent cavity <NUM> has a structure of the chamber <NUM> in which the light window <NUM> is smaller than the bottom wall <NUM>, such that the bottom wall <NUM> has a greater optical extend than the light window <NUM>, thereby increasing the collection efficiency.

After the excited light is emitted from the light window <NUM>, it passes through the light condensing device <NUM> again. It can be understood that, at this time, the light condensing device <NUM> has a divergent effect on the excited light, and the excited light diverged by the light condensing device <NUM> finally reaches the light splitting element <NUM> and is transmitted through the light splitting element <NUM>.

<FIG> is a structural schematic diagram of a light source device according to an Embodiment <NUM> of the present disclosure is illustrated. Referring to <FIG>, the light source device <NUM> includes an exciting light source <NUM>, a light homogenizing element <NUM>, a light splitting element <NUM>, a light condensing device <NUM>, a pattern plate <NUM>, a first driving device <NUM>, and a fluorescent cavity <NUM>.

Similar to parts of the structure of the Embodiment <NUM>, in the present embodiment, exciting light is also generated by the exciting light source <NUM>. The exciting light sequentially passes through the light homogenizing element <NUM>, the light splitting element <NUM>, and the light condensing device <NUM>. The present embodiment differs from the Embodiment <NUM> in that, after the exciting light passes through the light condensing device <NUM>, it first passes through the pattern plate <NUM> and then is incident to the fluorescent cavity <NUM>. The first driving device <NUM> is connected to the pattern plate <NUM> and drives the pattern plate <NUM> to move.

The structures of the exciting light source <NUM>, the light homogenizing element <NUM>, the light splitting element <NUM>, the light condensing device <NUM>, and the fluorescent cavity <NUM> in the present embodiment are respectively the same as the structures of the exciting light source <NUM>, the light homogenizing element <NUM>, the light splitting element <NUM>, the light condensing device <NUM>, and the fluorescent cavity <NUM> in the Embodiment <NUM>, which are not described in detail herein again.

Referring to <FIG> in combination, the pattern plate <NUM> is disposed between the light condensing device <NUM> and the fluorescent cavity <NUM> and located on an optical path of the exciting light emitted from the light condensing device <NUM>. Through the pattern plate <NUM>, the emitted excited light have a shape of a pattern of the pattern plate. The pattern plate <NUM> includes a first region <NUM> and a second region <NUM>. The second region <NUM> is disposed around the first region <NUM>.

The first region <NUM> is a central pattern region, and a pattern of the first region <NUM> can be designed according to specific requirements. In the present embodiment, the first region <NUM> is in a pentagonal star pattern. In other embodiments, the first region <NUM> may also have other shapes, for example, a circular, square, or rectangular pattern, which is not limited in the present disclosure.

In addition, a surface of the first region <NUM> facing towards the light condensing device <NUM> is provided with an anti-reflection film, and the anti-reflection film is configured to transmit the exciting light and reduce reflection of the exciting light.

The second region <NUM> is disposed around the first region <NUM>. The second region <NUM> is a non-pattern region. A surface of the second region <NUM> facing towards the light condensing device <NUM> is provided with a filter film, and the filter film is configured to reflect the exciting light and transmit the excited light. In the present embodiment, the filter film is configured to transmit blue exciting light.

The driving device <NUM> is connected to the pattern plate <NUM> and can drive the pattern plate <NUM> to rotate.

Similarly, the fluorescent cavity <NUM> is similar in structure to the fluorescent cavity <NUM> in the Embodiment <NUM>. The fluorescent cavity <NUM> in the present embodiment also includes a casing <NUM>, a chamber <NUM>, and a fluorescent layer <NUM>. Similarly, the exciting light, after incident into the chamber <NUM>, excites the fluorescent layer <NUM> to generate excited light. In addition, the chamber <NUM> also has a light window <NUM>, a bottom wall <NUM>, and side walls <NUM>. The chamber <NUM> has the same structure as the chamber <NUM> in the Embodiment <NUM>, which is not described in detail herein. Without doubt, the chamber <NUM> may also be in the shape of a pyramid shape, a spherical shape, an ellipsoid shape, a cylindrical shape, or a prism shape, which is not limited in the present disclosure.

In addition, the light window <NUM> has a larger area than the first region <NUM>. In the present embodiment, the first region <NUM> is located within a range of the projection of the light window <NUM> on a surface of the pattern plate <NUM>.

The present embodiment differs from the Embodiment <NUM> in that after the exciting light passes through the light condensing device <NUM>, it reaches a top surface of the pattern plate <NUM>, then further passes through the pattern plate <NUM>, and is incident to the chamber <NUM> from the light window <NUM>. Specifically, the exciting light converged by the light condensing device <NUM> is incident to the chamber <NUM> from the first region <NUM> of the pattern plate <NUM>.

The exciting light irradiates the fluorescent layer <NUM> and then excites the fluorescent layer <NUM> to generate excited light which is reflected in the form of Lambertian light. In the chamber <NUM>, the excited light in small-angle is directly emitted from the light window <NUM> of the chamber <NUM> at a small angle, and if it is irradiated to the first region <NUM> of the pattern plate <NUM>, a part of the excited light is emitted after passing through the first region <NUM>, then passes through the light condensing device <NUM> and is finally transmitted from the light splitting element <NUM>; the other part of the excited light is irradiated to the second region <NUM> of the pattern plate <NUM>, and the excited light is reflected by the second region <NUM> and then return to the chamber <NUM>, so that it can be continuously reflected, it is finally emitted from the first region <NUM> after being reflected by the side wall <NUM> and the bottom wall <NUM> for one or more times.

<FIG> is a structural schematic diagram of a light source device according to an Embodiment <NUM> of the present disclosure. Referring to <FIG>, the light source device <NUM> includes an exciting light source <NUM>, a light homogenizing element <NUM>, a light splitting element <NUM>, a light condensing device <NUM>, a pattern plate <NUM>, a first driving device <NUM>, a control device <NUM>, and a fluorescent cavity <NUM>. Similar to the structure in the Embodiment <NUM>, in the present embodiment, exciting light is also generated by the exciting light source <NUM>. The exciting light sequentially passes through the light homogenizing element <NUM>, the light splitting element <NUM>, the light condensing device <NUM>, and the pattern plate <NUM>, and then it is incident to the fluorescent cavity <NUM> and generates excited light in the fluorescent cavity <NUM>. The first driving device <NUM> drives the pattern plate <NUM> to move. The present embodiment differs from the Embodiment <NUM> in that the light source device <NUM> in the present disclosure further includes a control device <NUM>, and the control device <NUM> is respectively electrically connected to the exciting light source <NUM> and the first driving device <NUM>.

Similarly, the structure of the fluorescent cavity <NUM> is similar to that of the fluorescent cavity <NUM> in the Embodiment <NUM> The fluorescent cavity <NUM> in the present embodiment also includes a casing <NUM>, a chamber <NUM>, and a fluorescent layer <NUM>. Similarly, the exciting light is incident to the chamber <NUM> and then excites the fluorescent layer <NUM> to generate excited light. In addition, the chamber <NUM> also has a light window <NUM>, a bottom wall <NUM>, and a side wall <NUM>. The exciting light is incident into the chamber <NUM> through the light window <NUM>, and the structure of the chamber <NUM> is the same as the basic structure of the chamber <NUM> in the Embodiment <NUM>, which is not described in detail herein.

In the present embodiment, since the excited light emitted from the light window <NUM> of the fluorescent cavity <NUM> is reflected in the second region and incident to the fluorescent cavity <NUM> again to be used, until it is emitted from the first region of the pattern plate <NUM>. Therefore, when the first region of the pattern plate <NUM> adopts different patterns and thus has different areas, illuminance formed by the exciting light emitted from the fluorescent cavity <NUM> in the first region is also different, which will result in inconsistence of the brightness of the projection image. The illuminance=luminous flux/illumination area. Therefore, it is required that the ratio of the luminous flux of the illumination light to the illumination area is constant to achieve the consistency of the illuminance.

In the present embodiment, the control device <NUM> is disposed between the exciting light source <NUM> and the first driving device <NUM>. The control device <NUM> is respectively electrically connected to the exciting light source <NUM> and the first driving device <NUM>. Specifically, the control device <NUM> can monitor and receive status information from the first driving device <NUM> and accordingly adjusts power of the exciting light source <NUM> based on the received status information. In other words, the control device <NUM> controls the power of the exciting light by controlling the driving current of the exciting light source <NUM> and further controls, in such a manner, the luminous flux generated by the fluorescent cavity <NUM>. For example, the ratio of areas of the patterns <NUM>, <NUM>, and <NUM> in the first region of the pattern plate <NUM> is <NUM>: <NUM>: <NUM>. The pattern plate <NUM> is rotated by the first driving device <NUM> until the light window <NUM> of the fluorescent cavity <NUM> is aligned with the patterns <NUM>, <NUM>, and <NUM>, respectively, the control device <NUM> controls the ratio of the power of the exciting light of the exciting light source <NUM> to be <NUM>: <NUM>: <NUM>, so as to achieve the consistency of the illuminance.

<FIG> is a structural schematic diagram of a light source device according to an Embodiment <NUM> of the present disclosure. As shown in <FIG>, the light source device <NUM> includes an exciting light source <NUM>, a light homogenizing element <NUM>, a light splitting element <NUM>, a quarter wave-plate <NUM>, a light condensing device <NUM>, a light splitting lens <NUM>, and a fluorescent cavity <NUM>. The exciting light source <NUM> generates exciting light. The exciting light sequentially passes through the light homogenizing element <NUM>, the light splitting element <NUM>, the quarter wave-plate <NUM>, the light condensing device <NUM>, and the light splitting lens <NUM>, and then it is incident into the fluorescent cavity <NUM>. The fluorescent substance in the fluorescent cavity <NUM> is excited by the exciting light to generate excited light which is emitted from the fluorescent cavity <NUM> and finally transmitted out from the light splitting element <NUM> after passing through the light splitting lens <NUM>, the light condensing device <NUM>, the quarter wave-plate <NUM>, and the light splitting element <NUM>.

In the present embodiment, the exciting light source <NUM> is a laser of s-polarized blue light, and configured to generate s-polarized blue exciting light.

The structure of the light homogenizing element <NUM> is basically the same as that of the light homogenizing element <NUM> in the Embodiment <NUM>, which is not described in detail herein.

The light splitting element <NUM> is located on the optical path of the exciting light emitted from the light homogenizing element <NUM>. A polarizing film (not shown) is disposed on a surface of the light splitting lens <NUM> facing towards the light homogenizing element <NUM>. The polarizing film is a polarizing film corresponding to a blue light band, and it can reflect the s-polarized blue exciting light and transmit p-polarized blue exciting light. Therefore, the light splitting element <NUM> can reflect the s-polarized blue exciting light passing through the light homogenizing element <NUM>.

The quarter wave-plate <NUM> is located on the optical path of the light reflected by the light splitting element <NUM>. In the present embodiment, the quarter wave-plate <NUM> is disposed between the light splitting element <NUM> and the light condensing device <NUM> and close to a top surface of the light condensing device <NUM>. The quarter wave-plate <NUM> is located on the optical path of the exciting light reflected by the light splitting element <NUM> and receives the exciting light reflected by the light splitting element <NUM>, and it is perpendicular to the direction of the exciting light reflected by the light splitting element <NUM>. In other words, the exciting light emitted by the light splitting lens <NUM> is perpendicularly incident to the quarter wave-plate <NUM>. The quarter wave-plate <NUM> is configured to change the polarization state of the exciting light. In the present embodiment, the quarter wave-plate is configured to change the s-polarized blue exciting light into the p-polarized blue exciting light.

The light condensing device <NUM> is on the optical path of the exciting light emitted from the quarter wave-plate <NUM> and converges the exciting light passing through the light condensing device <NUM>. The structure of the light condensing device <NUM> is basically the same as that of the light condensing device <NUM> in the Embodiment <NUM>, which is not described in detail herein.

The structure of the fluorescent cavity <NUM> is also similar to that of the fluorescent cavity <NUM> in the Embodiment <NUM>. The fluorescent cavity <NUM> in the present embodiment also includes a casing <NUM>, a chamber <NUM>, and a fluorescent layer <NUM>. The chamber <NUM> has a light window <NUM>, a bottom wall <NUM>, and side walls <NUM>. The structure and the principle for generating exciting light of the chamber <NUM> are the same as those of the chamber <NUM> in the Embodiment <NUM>, which is not described in detail herein.

The light splitting lens <NUM> is located on the optical path of the exciting light emitted from the light condensing device <NUM>. Specifically, the light splitting lens <NUM> is disposed between the light condensing device <NUM> and the fluorescent cavity <NUM> and close to the top of the fluorescent cavity <NUM>. Further, the light splitting lens <NUM> is disposed on and covers top of the light window <NUM>. The light splitting lens <NUM> is configured to reflect a part of the exciting light and transmit the remaining part of the exciting light. In the present embodiment, the light splitting lens <NUM> can reflect <NUM>% of the exciting light irradiated onto the surface thereof and transmit the remaining <NUM>% of the exciting light, and the transmitted exciting light is incident to the fluorescent cavity <NUM> through the light window <NUM>. In this case, the excited light is generated after the exciting light is incident to the fluorescent cavity <NUM>, as in the Embodiment <NUM>, which is not limited in the present disclosure.

The excited light is emitted from the light window <NUM> and is first transmitted through the light splitting lens <NUM>. The excited light transmitted through the light splitting lens <NUM> and the exciting light reflected by the light splitting lens <NUM> are mixed to form white light. The white light passes through the light condensing device <NUM> and the quarter wave-plate <NUM>, sequentially. In this case, the exciting light reflected by the light splitting lens <NUM> has passed through the quarter wave-plate <NUM> twice, and thus the exciting light is transformed to the p-polarization state from the s-polarization state, and is finally emitted through the light splitting element <NUM>.

<FIG> is a structural schematic diagram of a light source device according to an Embodiment <NUM> of the present disclosure. As shown in <FIG>, the light source device <NUM> includes an exciting light source <NUM>, a light homogenizing element <NUM>, a light splitting element <NUM>, a quarter wave-plate <NUM>, a light condensing device <NUM>, a filter wheel <NUM>, a first driving device <NUM>, and a fluorescent cavity <NUM>.

The exciting light source <NUM> generates exciting light. The exciting light is incident into the fluorescent cavity <NUM> after passing through the light homogenizing element <NUM>, the light splitting element <NUM>, the quarter wave-plate <NUM>, the light condensing device <NUM>, and the filter wheel <NUM>, sequentially. The fluorescent substance in the fluorescent cavity <NUM> is excited by the exciting light to generate excited light, and the excited light is emitted from the fluorescent cavity <NUM>, and is finally emitted from the light splitting element <NUM> after sequentially passing through the filter wheel <NUM>, the light condensing device <NUM>, the quarter wave-plate <NUM>, and the light splitting element <NUM>. The first driving device <NUM> is connected to the filter wheel <NUM> and drives the filter wheel <NUM> to rotate.

The structures of the exciting light source <NUM>, the light homogenizing element <NUM>, the light splitting element <NUM>, the quarter wave-plate <NUM>, and the light condensing device <NUM> in the present embodiment are respectively the same as the corresponding structures of the exciting light source <NUM>, the light homogenizing element <NUM>, the light splitting element <NUM>, the quarter wave-plate <NUM> and the light condensing device <NUM> in the Embodiment <NUM>, which is not described in detail herein.

The filter wheel <NUM> includes a plurality of regions, and each of the regions is provided with one of filter sheets <NUM> having different transmittances for the exciting light. For example, multiple filter sheets <NUM> are provided. Since the exciting light source <NUM> in the present embodiment is a laser of s-polarized blue light and configured to generate s-polarized blue exciting light, the regions on the filter wheel <NUM> are provided with filter sheets <NUM> having different transmittances for the blue exciting light, respectively.

In the light source device <NUM> of the present embodiment, the filter wheel <NUM> and the first driving device <NUM> replace the light splitting lens of the Embodiment <NUM> together, so as to achieve adjustment of a dynamic color temperature. Specifically, as shown in <FIG> is a structural schematic diagram of a filter wheel of the light source device <NUM> shown in <FIG>.

The fluorescent cavity <NUM> also has a similar structure as the fluorescent cavity <NUM> in the Embodiment <NUM>. The fluorescent cavity <NUM> in the present embodiment also includes a casing <NUM>, a chamber <NUM>, and a fluorescent layer <NUM>. The chamber <NUM> has a light window <NUM>, a bottom wall <NUM>, and side walls <NUM>. The structure and the principle for generating exciting light of the chamber <NUM> are the same as those of the chamber <NUM> in the Embodiment <NUM>, which is not described in detail herein.

The filter wheel <NUM> is disposed at the light window <NUM> of the fluorescent cavity <NUM> and driven to rotate by the first driving device <NUM>. When the filter wheel <NUM> rotates to a position where the filter sheet <NUM> with a high transmittance to the blue exciting light directly faces the light window <NUM>, the blue exciting light used for exciting the fluorescent layer <NUM> in the fluorescent cavity <NUM> is relatively more, and the blue exciting light that is reflected is relatively less. That is, the blue exciting light is relatively less in the spectrum of the emitted illumination light, and thus the illumination system has a relatively low color temperature.

When the filter wheel <NUM> rotates to a position where the filter sheet <NUM> with a low transmittance to the blue exciting light directly faces the light window <NUM>, the blue exciting light used for exciting the fluorescent layer <NUM> in the fluorescent cavity <NUM> is relatively less, and the blue exciting light that is reflected is relatively more. That is, the blue exciting light is relatively more in the spectrum of the emitted illumination light, and thus the illumination system has a relatively high color temperature. In this way, through controlling the rotation of the filter wheel <NUM> by the first driving device <NUM>, the dynamic color temperature of the light source device <NUM> can be adjusted.

The present disclosure also provides a projection system (not shown), and the projection system includes a light source device, which may be the light source device described in any of the above embodiments.

In view of the above, on the one hand, since the area of the light window of the fluorescent cavity is smaller than the area of the fluorescent layer, energy of the exciting light does not change during the process of being incident into the fluorescent cavity. In this case, the size of the light spot on the fluorescent layer is significantly larger than the size of the light window. It can be understood that the distance between the light window and the focus is much shorter than the distance between the fluorescent layer and the focus. In this case, as the size of the light spot on the fluorescent layer is significantly larger than the size of the light window, the power density of the exciting light decreases and the excitation efficiency increases during the excitation of the fluorescent layer by the exciting light. In addition, the area of the fluorescent layer is relatively larger, and thus a heat dissipation region on a back surface of the fluorescent layer is greatly increased, such that a relatively large heat exchange area reduces a thermal saturation effect of the fluorescent substance, thereby further improving the excitation efficiency of the fluorescent substance.

On the other hand, the excited light is reflected in the form of Lambertian light. In the fluorescent cavity, the excited light in small-angle is directly emitted from the light window of the fluorescent cavity, and the excited light in large-angle is repeatedly reflected by the inner side walls and the bottom wall, finally emitted from the light window at a small angle. That is, all the excited light emitted from the light window of the fluorescent cavity is emitted at a small angle, which improves the collection efficiency of the light condensing device. That is, since the fluorescent cavity has a structure in which the light window is smaller than the bottom wall, the optical extend of bottom wall is greater than that of the light window, thereby increasing the collection efficiency.

Claim 1:
A light source device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), comprising:
an exciting light source (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for generating exciting light;
a light condensing device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
a fluorescent cavity (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
wherein the fluorescent cavity comprises a chamber (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and a fluorescent layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the chamber (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a light window (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) allowing light to enter and exit and a bottom wall (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) opposite to the light window (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and the fluorescent layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) being provided on a surface of the bottom wall (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
wherein the exciting light is converged by the light condensing device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), then incident to a surface of the fluorescent layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) from the light window (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to form a light spot which excites the fluorescent layer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to generate excited light, wherein an area of the light window (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is smaller than an area of the light spot, and the excited light is emitted from the light window (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
characterized in that light source device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) further comprises:
a light homogenizing element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the exciting light emitted from the exciting light source (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is homogenized by the light homogenizing element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and
a light splitting element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the light splitting element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) receives the exciting light homogenized by the light homogenizing element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and is configured to reflect a part of the exciting light and transmit the excited light,
wherein the exciting light source (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and the chamber (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) are disposed in a same side of the light splitting element (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>).