WO2013102358A1

WO2013102358A1 - Light-emitting device and projection apparatus

Info

Publication number: WO2013102358A1
Application number: PCT/CN2012/080737
Authority: WO
Inventors: 杨毅
Original assignee: 深圳市光峰光电技术有限公司
Priority date: 2012-01-07
Filing date: 2012-08-29
Publication date: 2013-07-11
Also published as: CN102854723A; CN102854723B

Abstract

A light-emitting device (500) comprises an exciting light source used for emitting exciting light (501), a wavelength conversion device (502) used for receiving the exciting light (501) and emitting excited light. The wavelength conversion device (502) comprises at least a red light section (503a). The light-emitting device (500) also comprises a driving device (504) used for driving the wavelength conversion device (502) to periodically move relative to the exciting light (501), a light filtering device (507) moving synchronously with the wavelength conversion device (502), and a light collection device. And the light filtering device (507) comprises at least a red light filtering section (507a) corresponding to the red light section (503a), the red light filtering section (507a) filters the light emitted from the red light section (503a) into red light. The light collecting device is used for collecting and converging the light emitted from the wavelength conversion device (502) and enabling the incident angle of the light entering the light filtering device(507), to be larger than or equal to 25 degrees and smaller than or equal to 45 degrees. The present invention is also related to a projection apparatus comprising the light emitting device (500).

Description

Description illuminating device and projection device

The present invention relates to the field of optical technology, and in particular to a light emitting device and a projection device. Branch

At present, projection display has attracted more and more attention. At present, the mainstream projection display technology uses a digital micromirror device (Di gi ta l Mi cromi rror Dev ice, leg D) as a light valve to modulate a time-series monochromatic light sequence, by timing with the monochromatic light sequence. Simultaneously obtaining a time-series monochromatic light image on the screen, and finally relying on the visual residual effect of the human eye to superimpose each monochromatic light image to form a color image.

In the projection display technology, the formation of time-series monochromatic light sequences is a key technology. One method is to use a white light source to focus and illuminate on a filter disc. The filter disc is distributed with a plurality of color filters along the circumferential direction, and the filters are sequentially rotated by the white light source according to the periodic rotation of the filter disc. Focusing on the spot, which in turn forms a periodic sequence of colors.

Another possible method is disclosed in U.S. Patent No. 7,547,114, which uses an excitation source to illuminate a fluorescent pink wheel having a plurality of phosphor segments distributed in the circumferential direction, and the phosphors are sequentially 3⁄4^ with the rotation of the color wheel. In turn, a periodic sequence of colors is achieved. At present, this kind of program has become a hot spot of research.

However, the problem with the read scheme is that the efficiency of the red phosphor is too low and the lifetime is too short, which in turn makes red light a bottleneck in the efficiency and lifetime of the entire light source system.

In order to solve the problem of generating red light, it has been proposed to use a high-efficiency and stable yellow or green phosphor to filter out the green light component in the emission spectrum through a filter to generate red light. The emission of the most commonly used yellow and green phosphors is shown as 101 in Figure 1. It is generally defined that the portion of the light borrowed above 590 为 is red, which is represented as spectral region 102 in FIG. Of course, since the color of light varies continuously with wavelength, the boundary of the 590 leg here is only an example for convenience.

In practical applications, the filter is mounted on a filter wheel that rotates in synchronization with the fluorescent pink wheel, so that each filter on the filter wheel and the fluorescent color of a certain color on the fluorescent pink wheel The powder segment corresponds.

Since yellow and green phosphors have been shown to have very good stability, this method can well solve the problem of red light life bottlenecks. However, the introduction of filters has created new problems.

The transmittance curve of a typical filter is shown in Figure 2, where 201 is the transmittance curve when the incident angle of the incident light is 0 degrees, and 202, 203, 204, and 205 are the incident rays respectively. The angle is the transmittance curve at 20 degrees, 40 degrees, 60 degrees, and 80 degrees. It can be seen that the transmittance curve of the filter drifts to the short wavelength direction as the incident angle increases. Shift, that is, the filter has different responses to light of different incident angles.

Considering that the yellow or green light emitted by the fluorescent pink wheel is incident on the read filter, there must be an angular range, that is, a light cone is formed, so the response of the read filter to the incident yellow or green light should be Reading is the combined effect of the response to light at different angles. After the experiment, the comprehensive transmittance curve of the filter can be obtained for the incident light of different angle ranges, as shown in Fig. 3a, where 302 is the comprehensive transmission of the filter for the cone with an incident half angle of 20 degrees. The rate curves, 303, 304, and 305 are the comprehensive transmittance curves of the filters for the light cones whose incident half angles are 40 degrees, 60 degrees, and 80 degrees, respectively. It can be understood that when the incident light of the same spectrum is incident on the filter at a light cone forming a different incident angle, the color and luminous flux of the filtered outgoing light are different.

In order to obtain a specific red color coordinate, the integrated transmittance curve can be shifted by designing a filter. For example, when the color of the outgoing light that is desired to be filtered is more reddish, the integrated transmittance curve can be shifted to a long wavelength.

Through experiments, the inventors discovered such a rule: Under the premise of filtering the yellow light spectrum shown in 101 of Fig. 1 to the same red light color coordinate, the larger the angular range of the incident light cone, the filtered The lower the luminous flux of red light, as shown in Figure 3b. In the figure, the abscissa is the half angle of the incident light cone, and the ordinate is the relative luminous flux of the filtered red light; in this experiment, the color coordinates of the red light filtered by each cone are (0.664, 0. 33 ).

It can be seen that in order to achieve the maximum red light flux output, the angle of the light cone incident on the filter is as small as possible. However, according to the law of conservation of optical spread, the smaller angle of the light cone means that the size of the spot is increased, and the increase in the size of the spot further causes the spoke light on the filter wheel where the filter is located (spoke l ight) increase. When the seams of two adjacent filters are rotated onto the spot formed by the light cone, the two filters simultaneously act on the spot to form a crosstalk, and the filtered light at this time is called a spoke. Light. The presence of spoke light reduces the contrast and effect of the image display. It is conceivable that the smaller the angle of the light cone half angle, the larger the size of the spot, and the larger the spoke light, the lower the image display quality.

In summary, the current red light flux and the display quality of the image form a contradiction. Summary of the invention

The main technical problem solved by the present invention is to solve the contradiction between the above-mentioned red light flux and the display quality of the image. The present invention provides a light-emitting device comprising an excitation light source for emitting excitation light, and a wavelength conversion device for receiving excitation light and emitting a laser light, the wavelength conversion device comprising at least two color segments, wherein at least one red light is included The color segment, the red color segment includes yellow or green wavelength conversion material. Also included is a driving device for driving the wavelength conversion device to periodically move relative to the excitation light and to periodically illuminate at least two color segments of the wavelength conversion device with the sequentially excited light. The light emitting device further includes a filter device disposed in synchronization with the wavelength conversion device disposed at a rear end of the optical path of the wavelength conversion device, the filter device including at least two filter segments corresponding to at least two color segments of the wavelength conversion device, The at least two filter segments include at least a red filter segment corresponding to the red color segment, and the read red filter segment filters the light emitted by the red color segment into red light; further comprising being disposed in the wavelength conversion device and A light collecting device between the optical paths of the filter device, the read light collecting device is configured to collect and converge the light emitted by the wavelength converting device so that the incident angle incident on the filter device is greater than or equal to 25 degrees and less than or equal to 45 degrees. The present invention also provides a projection apparatus comprising the above-described illumination apparatus.

In the illuminating device and the projection device of the present invention, the optimization and control of the incident angle range of the light incident on the filter device, taking into account the red light flux and the image display quality, achieving a compromise between the two and optimization of the overall performance. . DRAWINGS

Figure 1 is an illuminating spectrum of a conventional yellow phosphor;

2 is a transmittance curve of a conventional filter for filtering red light for different incident angle rays;

Figure 3a is a view of the filter of Figure 2 for light cones of different angles of incidence;

Figure 3b is a graph showing the relationship between the filtered red light flux and the half angle of the incident light cone of the spectrum shown in Figure 1 on the premise of achieving the same red color coordinates;

Figure 4 is a graph showing the relationship between the red light flux and the size of the incident light spot after filtering the spectrum shown in Figure 1 on the premise of achieving the same red light color coordinates;

5a, 5b and 5c are schematic views of a first embodiment of the present invention;

Figure 6 is a schematic view of a second embodiment of the present invention;

Figure 7 is a schematic view of a third embodiment of the present invention. detailed description

The inventors obtained the relationship between the red light flux filtered by the yellow light spectrum shown in Fig. 1 and the spot size of the incident light under the premise of achieving the same red light color coordinate, as shown in Fig. 4. Wherein, 401 refers to a relative spot size and a red light relative brightness when the half angle of the incident light cone incident on the filter is 10 degrees, and 402 to 409 respectively refer to the incident light cones incident on the filter. The half angle is the relative spot size and the relative brightness of red light at 20 degrees, 25 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, and 70 degrees. It can be seen from the figure that when the half angle of the incident light cone is between 10 and 25 degrees, the relative spot size is large and the relative brightness of the red light is not significantly improved, while the incident light cone has a half angle of 45 degrees and 70 degrees. When the degree is between the degrees, the relative brightness of the red light is too low. When the half angle of the incident light cone is greater than or equal to 25 degrees and less than or equal to 45 degrees, the relative spot size and the relative brightness of the red light can be achieved, achieving the best compromise between the two and the overall performance. optimization. Wherein, a more preferred half angle of the incident light cone is 25 degrees or more and 35 degrees or less, because the red light has a relatively large relative brightness, and the angle range is relatively matched with the incident light angle of the leg D at the rear end, which is convenient for optics. design.

The structure of the first embodiment of the present invention is as shown in Fig. 5a, in which the light-emitting device 500 includes a light source (not shown) for emitting 3⁄4^ light 510, and for receiving 3⁄4^ light 5 01 And transmitting a laser wavelength conversion device 502. Figure 5b is a front elevational view of the read wavelength conversion device 502, and the read wavelength conversion device 502 includes a wavelength conversion layer 503. In the present embodiment, both the wavelength conversion device 502 and the wavelength conversion layer 503 are processed into a circular shape, and the wavelength conversion layer 503 includes two color segments 530a and 530b arranged in the circumferential direction. The color segment 5 03a is a red color segment, and the red color segment includes a yellow wavelength conversion. Material, the excited light of the yellow wavelength conversion material is shown in Figure 1; the color segment 503b is a green color segment. In the present embodiment, the wavelength conversion device 502 further includes a substrate 511, and the wavelength conversion layer 503 is attached to one surface of the substrate 511, and the surface has a reflective property. There are various methods for forming the wavelength conversion layer 503 on the surface of the substrate 511. For example, the wavelength conversion material is mixed with a binder and applied to the surface of the substrate 511 to form a wavelength conversion layer after curing, for example, a wavelength conversion material and A liquid transparent material such as glass or epoxy resin is mixed and cast to form a sheet, and the sheet is fixed to the surface of the substrate 511 to form a wavelength conversion layer.

The illumination device 500 further includes a drive device 504 for driving the wavelength conversion device 502 to periodically move relative to the excitation light 501 and to periodically illuminate the two color segments 503a and 503b of the wavelength conversion device 502 by the excitation light 501. In the present embodiment, the driving device 504 is a motor that drives the wavelength conversion device 502 to rotate at a constant speed around its center, and the color segments 503a and 503b are sequentially illuminated by the excitation light 501 to generate laser yellow light and green light, and the laser light is divided into two. The portion is directly emitted outside the wavelength conversion device 502, and the other portion is incident on the surface of the substrate 511, and is finally emitted outside the wavelength conversion device 502. Also emitted at the same time may also include excitation light that is directly reflected from the surface of the wavelength conversion device 502, which together constitute the outgoing light 510 of the wavelength conversion device 502.

The illuminating device 500 further includes a filtering device 507 disposed in synchronization with the wavelength converting device 502 at the rear end of the optical path of the wavelength converting device 502, and a front view of the reading filter device 507 is as shown in Fig. 5c. The filter device 507 also has a circular outer shape comprising two filter segments 507a and 507b corresponding to the two color segments of the wavelength conversion device 502, wherein the filter segment 507a corresponds to the color segment 503a, and the filter segment 507b corresponds to the color segment 503b. Corresponding here means: when a certain color segment of the wavelength conversion device 502 moves to the illumination range of the excitation light and emits the laser light, the corresponding filter segment also moves to the rear optical path of the color segment and Filter the light from the color section.

In the present embodiment, the filter section 507a is a red filter section corresponding to the red color section 503a. The read red filter segment is an interference filter that transmits red light and reflects green light, and transmits the light emitted by the red light color band 503a into red light in a transmissive manner.

The light emitting device 500 further includes a light collecting device disposed between the wavelength paths of the wavelength converting device 502 and the filter device 507. The light collecting means is for collecting and condensing the light emitted from the wavelength converting means 502 so that the incident angle incident on the filtering means 507 is 25 degrees or more and 45 degrees or less. In the present embodiment, the light collecting means includes a curved reflector 506 and a tapered integrating rod 505.

A through hole 506a is present in the curved reflector 506, and a reflective layer is formed on the inner surface of the curved reflector 506. The tapered integrator rod 505 includes a light entrance port 505a and a light exit port 505b. The light is incident on the tapered integrator rod 505 from the light entrance port 505a and is reflected from the light exit port 505b after being internally reflected multiple times. According to the principle of conservation of optical spread, the optical spread of the light at the light entrance 505a and the light exit 505b of the tapered integrator 505 remains unchanged, as shown in the formula (1):

3⁄4 in = Ω out ( 1 )

Where _λ and the areas of the light entrance 505a and the light exit 505b, respectively, Ω _λ and Ω _ψ are respectively incident on the light cone The entrance aperture 505a and the solid angle exiting the exit aperture 505b, and the solid angle of the cone of light is generally proportional to the square of the sine of its half angle. According to FIG. 4 and the above discussion, in the present invention, it is desirable that the half angle of the light cone emitted to the light exit opening 505b is greater than or equal to 25 degrees and less than or equal to 45 degrees, and in the present embodiment, the light cone half angle incident on the light entrance opening 505a. It is 90 degrees, so the area ratio of the light entrance 505a and the light exit 505b in this embodiment can be obtained:

0.179 < ^ < 0.5 ( 2 ) Preferably, the half angle of the light cone emerging from the light exit opening 505b is 25 degrees or more and 35 degrees or less, so that the area ratio of the preferred light entrance port 505a to the light exit port 505b can be obtained:

0.179 < ^ < 0.329 { 3 ) In the present embodiment, the curved reflector 506 has a hemispherical inner surface, and the position of the wavelength conversion device 502 by the itt and the position of the light entrance 505a of the tapered integrator rod 505 are related to the hemisphere. The shaped spheres are placed symmetrically. The excitation light 501 is incident on the surface of the wavelength conversion device 502 from the through hole 506a of the read arc reflector 506, while most of the energy in the outgoing light 510 of the wavelength conversion device 502 is incident on the reflective layer of the inner surface of the curved reflector 506. And the light incident port 505a of the ii taper integrator rod 505, the remaining small amount of energy leaks from the through hole 506a to form a loss. Since the size of the general through hole 506a is small, the partial loss is negligible.

The light beam emitted from the light exit port 505b of the tapered integrator rod 505 is incident on the filter device 507, and finally the filtered exit light 509 is obtained. Since the half angle of the light cone incident on the filter unit 507 is 25 degrees or more and 45 degrees or less, the brightness of the red light and the spot size in the outgoing light 509 are taken into consideration, and the overall performance of the system is optimized.

In the present embodiment, by using the tapered integrator rod 505 and the principle of conservation of optical spread, the compression of the half angle of the light cone can be achieved, thereby satisfying the angle requirement of the light cone incident on the filter unit 507. In fact, a tapered integrator is not a perfect optical expansion conservation device, and a composite parabol i c concentra tor can be used instead of the conical integrator. The CPC also has an entrance port and a light exit port, and the area ratio of the entrance port to the light exit port also needs to satisfy the formula (2) or (3) according to the principle of conservation of optical expansion. CPC is a better performing optical expansion conservation device, but its disadvantage is higher processing cost. This is prior art and will not be described here.

The tapered integrator rod can also be replaced by a lens, as discussed in the third embodiment below.

In this embodiment, the red wavelength segment 503a includes a yellow wavelength conversion material, and the excited light spectrum of the read yellow wavelength conversion material is as shown in FIG. 1; in fact, the red wavelength segment 503a may also be a green wavelength conversion material. As long as it is exposed to red light in the laser spectrum.

In the present embodiment, the color segment 503b is a green color segment including a yellow or green wavelength conversion material. Of course, the color segment can also be a color segment of other colors, which has no effect on the optimization of the red color segment of the present invention. Red color segment 503a and The green color segment 503b can even use the same wavelength converting material, for example, using a yellow wavelength converting material. When the red color segment is rotated to the irradiation position of the excitation light, the red filter segment corresponding to the red color segment is filtered yellow. The yellow light emitted by the wavelength conversion material is red light; when the green color segment is rotated to the irradiation position of the excitation light, the green light filter segment corresponding to the green light color segment filters the yellow light emitted by the yellow wavelength conversion material to be green light. .

It can be understood that the wavelength conversion device in the present invention may further include two or more color segments, and the filter device includes corresponding two or more filter segments. A commonly used structure is that the wavelength conversion device includes three color segments of a red color segment, a green color segment, and a blue color segment, wherein the red color segment includes a yellow or green wavelength conversion material, and the green color segment includes yellow or green. For wavelength conversion materials, the blue color segments have different choices depending on the wavelength of the light. When the 3⁄4 ^ light is blue light, the blue color segment may not include any wavelength conversion material, and the excitation light is directly used as the monochromatic light output, and the corresponding blue light filter segment may be the transparent glass coated with the antireflection film; When the excitation light is blue light, the blue color segment may also include a small amount of blue-green wavelength conversion material or green wavelength conversion material or yellow wavelength conversion material, and the output blue light is the laser of the wavelength conversion material and the remaining excitation light. Mixing; and when the excitation light is violet or ultraviolet, the blue color segment may include a blue wavelength conversion material. Another common structure is to add a yellow or white color segment based on the above three color segments, and a yellow wavelength conversion material for enhancing the brightness of white light.

In this embodiment, the curved reflector 506 having a hemispherical inner surface functions to collect the light-emitting device and emit it into the light-in port of the light collecting device 505. In fact, other methods can be used to achieve this. purpose. For example, a planar reflector, or a curved reflector having a parabolic inner surface, or a reflector having a stepped surface, as long as the collection wavelength conversion device can be illuminated and concentrated on the light entrance of the tapered integrator rod Just fine. This is an existing technology and will not be described here.

In the present invention, the filter device moves in synchronization with the wavelength conversion device; in the present embodiment, another drive device 508 is used to drive the filter device 507 to move, and the drive device 508 is synchronized with the drive device 504. A convenient way to maintain synchronization is to securely connect the drive unit 504 to the drive unit 508 to become an integral drive unit while driving the filter unit and the wavelength conversion unit. Of course this does not limit the use of circuit control to achieve synchronization between the two drives 504 and 508.

The mechanism in the second embodiment of the present invention is as shown in Fig. 6. Unlike the above embodiment, in the present embodiment, the filter unit 607 includes an angle of 45 degrees with respect to the optical axis of the incident light incident thereon. The filter surface 6071 has a function of filtering light by reflection. The filter surface includes at least two filter segments, wherein at least one red filter segment is included, the red filter segment reflects red light and transmits green light, and then reflects red light on the wavelength conversion device The light emitted by the color segment is filtered into red light.

The structure of the third embodiment of the present invention is as shown in Fig. 7, which has a different optical structure from the above two embodiments. Wherein, the wavelength conversion device 702 is excited by the excitation light 701 to generate a laser beam, which is collected by the light collection device 705 and Converging on the filter device 707 and filtering through the filter device 707 to form the outgoing light 709. The wavelength conversion device 702 is driven by the driving device 704 to move relative to the excitation light 701 while the filter device 707 is synchronized with the wavelength conversion device 702. The structures of the wavelength conversion device 702 and the filter device 707 are the same as those of the above embodiment, and will not be repeated here.

In this embodiment, preferably, the wavelength conversion device 702 further includes a spectral filter (not shown) disposed on a side of the wavelength conversion material that receives the excitation light, and the spectral filter transmits the excitation light while being reflected. laser.

In this embodiment, the light collecting device 705 includes a lens or a lens group, and the wavelength converting device and the filtering device are respectively located on the conjugate planes on both sides of the lens or the lens group optical path, which ensures that the light spot on the wavelength conversion device passes. The light collecting device 705 then forms an image of the spot on the filter device. Through optical design, the lens or lens group 705 also satisfies the principle of conservation of optical spread, as shown in equation (4):

^Ω^^Ω, ( 4 )

Wherein S and the area of the spot on the wavelength conversion device 702 and the filter device 707, respectively, and 0 ₂ are the solid angles of the light cone of the outgoing light collected by the light collecting device 705 on the wavelength conversion device 702, respectively, and incident on the filter. The solid angle of the light cone of the light device 707, wherein the corresponding half angle is approximately between 60 and 80 degrees. It can be seen that by design, the spot on the wavelength conversion device can be enlarged by the lens or lens group 705 on the filter device, that is, 0 ₂ can be made smaller at this time. Therefore, by adjusting the magnification of the imaging of the lens or lens group 705, the half angle of the light cone incident on the filter device can be made 25 degrees or more and 45 degrees or less.

The present invention also provides a projection apparatus comprising the above-described illumination apparatus.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the specification and the drawings of the present invention may be directly or indirectly applied to other related technologies. The scope of the invention is included in the scope of patent protection of the present invention.

Claims

Claim

A lighting device, comprising:

An excitation light source for emitting excitation light;

a wavelength conversion device for receiving excitation light and emitting a laser, the read wavelength conversion device comprising at least two color segments; for driving the wavelength conversion device to periodically move relative to the excitation light and to at least read the wavelength conversion device a driving device in which two color segments are periodically illuminated by the excitation light;

The at least two color segments of the wavelength conversion device include at least one red color segment, and the red light color segment includes a yellow or green wavelength conversion material;

Also includes:

a filter device disposed in synchronization with the wavelength conversion device at a rear end of the optical path of the wavelength conversion device, the filter device comprising at least two filter segments corresponding to at least two color segments of the wavelength conversion device, for at least The two filter segments include at least a red filter segment corresponding to the red color segment, and the read red filter segment filters the light emitted by the red segment into red light;

a light collecting device disposed between the wavelength conversion device and the optical path of the filter device, the light collecting device configured to collect and condense light emitted by the wavelength conversion device to be incident on the filter device It is 25 degrees or more and 45 degrees or less.

2. The light emitting device according to claim 1, wherein the red filter segment of the filter device transmits red light and reflects green light, and filters the light emitted by the red light color segment into a transparent manner. Red light.

3. The light emitting device according to claim 1, wherein the red filter segment of the filter device reflects red light and transmits green light, and reflects the light emitted by the red color segment into a reflective manner. Red light.

4. The light emitting device according to claim 1, wherein the light collecting device comprises a tapered integrator rod or a compound parabolic laser, and the tapered integrator rod or compound parabolic concentrator comprises an entrance port and an exit port. 5。 The ratio of the area of the light entrance to the light exit is greater than or equal to 0. 179 and less than or equal to ϋ. 5.

The light-emitting device according to claim 4, wherein an area ratio of the light entrance of the tapered integrator rod or the compound parabolic concentrator to the light exit port is greater than or equal to ϋ.179 and less than or equal to ϋ.329.

The light emitting device according to claim 1, wherein the light collecting device comprises a lens or a lens group, and the wavelength converting device and the filtering device are respectively located on a conjugate surface of the lens or the lens group optical path The lens or lens group is an enlarged image of the object on the side of the wavelength conversion device.

7. The light-emitting device according to claim 1, wherein an incident angle of light emitted from the wavelength conversion device incident on the filter device is 25 degrees or more and 35 degrees or less.

8. The illumination device of claim 1, wherein at least one of the at least two color segments of the wavelength conversion device comprises a green color segment, and the read green color segment comprises a yellow or green wavelength conversion material.

9. The illumination device of claim 1 or 8, wherein the wavelength conversion device comprises at least a red color segment, The green color segment and the blue color segment have three color segments, wherein the red color segment includes a yellow or green wavelength conversion material, the green color segment includes a yellow or green wavelength conversion material, and the blue color segment includes a blue wavelength conversion material or a blue-green light. A wavelength converting material or a green wavelength converting material or a yellow wavelength converting material or not including any wavelength converting material.

A projection apparatus comprising the light-emitting device according to any one of claims 1 to 9.