Optical path structure of an LCOS projector using a laser fluorescent ceramic light source

Abstract

The present invention provides an optical path structure of an LCOS projector using a laser fluorescent ceramic light source, which is applied in the field of projection display technology. The key points of its technical solution are: a blue excitation light source array emits blue excitation light to excite static fluorescent ceramics to produce red and green mixed light; a blue laser light source emits blue laser to supplement the blue laser, and then high-brightness red light, green light and blue laser are incident on the LCOS through processing by a light combining element, a polarization processing optical element, a color control optical group, a polarization beam splitting element, etc., and then emitted from the projection lens after modulation by the LCOS; the technical effect is that the wavelength of the excitation light can be stably converted, the heat dissipation performance and the anti-laser damage threshold of the phosphor are improved, and the output luminous flux of the light source is increased; and the projection image of the projection machine has the characteristics of high brightness, and the projection machine can also form clear images in bright environments, thereby solving the problem of unclear images when the projection machine is used in bright environments.

Description

Technical Field

[0001] The present invention relates to the field of projection display technology, and in particular to an optical path structure of an LCOS projection optical machine using a laser fluorescent ceramic light source. Background Art

[0002] The projector optical engine refers to the core component that converts the input signal into an image, which includes components such as light source, lens group, optical engine and display element; its function is to convert the input signal into a projected image through optical technology; with the continuous development of optical projection technology, projector optical engines are becoming more and more an indispensable and important tool for people's work, study and life; among them, laser light source is a commonly used light source type for projector optical engines, which has the advantages of high brightness, wide color gamut and clear image; its disadvantage is that the highly coherent laser will produce speckle phenomenon when reflected on the projection surface, affecting the viewing experience; using short-wavelength laser to excite fluorescence and then combining fluorescence with three-color laser is a common technical means to supplement brightness and reduce laser speckle.

[0003] At present, the Chinese invention with publication number CN117850141A discloses a wavelength conversion device, a light source system and a projection device, including a driving device, a substrate, a wavelength conversion element and a diffusion element, wherein: the driving device is connected to the substrate in a transmission manner, and the driving device is configured to drive the substrate to rotate around its axis; the diffusion element is arranged on the substrate, and the diffusion element is in a circular ring shape; the wavelength conversion element is arranged on the substrate in a circular ring shape, and the wavelength conversion element is arranged on the inner side of the diffusion element, or the wavelength conversion element is arranged on the outer side of the diffusion element, and the center of the diffusion element, the center of the substrate and the center of the wavelength conversion element correspond to each other, and the wavelength conversion device converts the wavelength of the excitation light through the wavelength conversion element to obtain the converted light.

[0004] In existing projection equipment, a driving device drives the substrate and drives the wavelength conversion element to rotate. The rotating wavelength conversion element converts the wavelength of the excitation light. However, the rotating wavelength conversion element is unstable and easily interfered with by external factors. For example, in-vehicle projectors are mostly used while the vehicle is moving. The bumps of the vehicle will interfere with the rotation of the wavelength conversion element, thereby affecting the wavelength conversion element of the excitation light. Summary of the Invention

[0005] The purpose of the present invention is to provide an optical path structure of an LCOS projection optical machine using a laser fluorescent ceramic light source, which has the advantage of being able to stably convert the wavelength of the excitation light, increase the laser power resistance threshold of the phosphor, increase the output luminous flux of the optical machine, and have the characteristics of high brightness.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides the following technical solutions:

[0007] An optical path structure of an LCOS projection optical machine using a laser fluorescent ceramic light source, comprising

[0008] a blue excitation light source array, the blue excitation light source array being used to emit blue excitation light; a blue laser light source, the blue laser light source being used to emit blue laser light;

[0009] Static fluorescent ceramics, a focusing collimating lens group is provided between the blue excitation light source array and the static fluorescent ceramics, the focusing collimating lens group is used to focus the blue excitation light on the static fluorescent ceramics, and the blue excitation light is converted into red and green mixed light after passing through the static fluorescent ceramics and then emitted and collimated and expanded after passing through the focusing collimating lens group;

[0010] A light combining element, which is used to combine the blue laser light and the red and green mixed light into mixed light and then emit the mixed light;

[0011] a polarization processing optical element, the polarization processing optical element being used to convert the mixed light into polarized light;

[0012] A color control optical group is used to separate polarized light into red, green, and blue lasers, and then control the passage or cutoff of the red, green, and blue lasers respectively, and finally combine the red, green, and blue lasers into one output without changing their polarization state and polarization direction at the time of incidence;

[0013] a polarization beam splitter element configured to reflect red light, green light, and blue laser light in a vertical polarization direction and transmit red light, green light, and blue laser light in a horizontal polarization direction;

[0014] LCOS is used to modulate the polarization state of red light, green light, and blue laser light in the same polarization direction and then reflect them to the projection lens.

[0015] In one embodiment of the present invention, a collimating lens array for collimating blue excitation light and a first dichroic mirror for reflecting blue excitation light and transmitting red and green mixed light are further included. The collimating lens array is located between the blue excitation light source array and the focusing collimating lens group; the first dichroic mirror is located between the collimating lens array and the focusing collimating lens group and between the focusing collimating lens group and the light combining element.

[0016] In one embodiment of the present invention, the static fluorescent ceramic is a copper-based fluorescent ceramic.

[0017] In one embodiment of the present invention, a collimating and beam expanding lens group is further included for collimating and expanding the blue laser to a desired size. The collimating and beam expanding lens group is located between the blue laser light source and the light combining element.

[0018] In one embodiment of the present invention, the light combining element is a second dichroic mirror for transmitting blue laser light and reflecting red and green mixed light.

[0019] In one embodiment of the present invention, the polarization processing optical element is a linear polarizer.

[0020] In one embodiment of the present invention, the color control optical assembly includes a color separation X prism, a color combination X prism, a first reflector, a second reflector, a third reflector, a fourth reflector, and three liquid crystal light valves;

[0021] The color separation X prism is arranged opposite to the linear polarizer, and the color combining X prism is arranged opposite to the color separation X prism;

[0022] The first reflector and the second reflector are respectively arranged on both sides of the color separation X prism and tilted toward the color combination X prism;

[0023] The third reflector and the fourth reflector are arranged on both sides of the color combining X prism and are inclined toward the color separating X prism;

[0024] The first reflector and the fourth reflector, and the second reflector and the third reflector are arranged opposite to each other;

[0025] The three liquid crystal light valves are respectively arranged between the first reflecting mirror and the fourth reflecting mirror, the color separation X prism and the color combination X prism, and the second reflecting mirror and the third reflecting mirror.

[0026] In one embodiment of the present invention, a fifth reflector is further provided opposite to the color-combining X-prism. A microlens array and a relay lens group are provided between the fifth reflector and the polarization beam splitting element.

[0027] In one embodiment of the present invention, the polarization beam splitting element is a polarization beam splitting prism, and a compensation plate is disposed between the polarization beam splitting prism and the LCOS.

[0028] As described above, the optical path structure of an LCOS projector using a laser fluorescent ceramic light source of the present invention has the following beneficial effects:

[0029] Static fluorescent ceramics have higher stability than dynamic wavelength conversion elements in the prior art; wherein the static fluorescent ceramics are copper-based fluorescent ceramics, which have good laser resistance and heat dissipation performance, and can improve the utilization rate of blue excitation light converted into red and green mixed light; and because the copper-based fluorescent ceramics have good laser resistance and heat dissipation performance, the light energy of the blue excitation light can be increased by increasing the number of blue excitation light sources in the blue excitation light source array and increasing the energy of a single blue excitation light source, thereby enabling the copper-based fluorescent ceramics to convert high-energy red and green mixed light; the blue laser is supplemented by a blue laser light source, and then the blue laser and the red and green mixed light are combined into mixed light by the light combining element and then emitted; the polarization processing optical element converts the mixed light into polarized light, the color control optical group divides the polarized light into red light, green light, and blue laser and then emits them; the liquid crystal light valve controls the red light, green light, and blue light. The passage and cutoff of the laser are uniformized by the synergistic effect of the microlens array and the relay lens. The uniformized light spot reflects the red light, green light, and blue laser in the same direction through the polarization splitter, and the high-brightness red light, green light, and blue laser are incident on the LCOS in a time-sharing manner. The LCOS then modulates the polarization state of the light incident on each pixel thereon and reflects it out. The reflected light passes through the polarization splitter, which transmits light with a certain polarization direction opposite to that of the transmitted light and reflects light perpendicular to the polarization direction of the transmitted light, thereby controlling the intensity of the light emitted from each LCOS pixel point. The intensity of the light emitted from each pixel is different, thereby forming an image. Finally, the image is projected through the projection lens; thereby realizing the high brightness of the projection screen of the projection optical machine, and the projection optical machine can also form clear images in bright environments, thereby solving the problem of unclear images when the projection optical machine is used in bright environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall optical path structure of an embodiment of the present invention.

[0031] Figure numerals: 1. blue excitation light source array; 2. blue laser light source; 3. collimating lens array; 4. collimating and expanding lens group; 5. focusing collimating lens group; 6. static fluorescent ceramic; 7. first dichroic mirror; 8. light combining element; 9. polarization processing optical element; 10. color separation X prism; 11. color combining X prism; 12. first liquid crystal light valve; 13. second liquid crystal light valve; 14. third liquid crystal light valve; 15. first reflector; 16. second reflector; 17. third reflector; 18. fourth reflector; 19. fifth reflector; 20. microlens array; 21. relay lens group; 22. polarization splitting element; 23. compensation plate; 24. LCOS; 25. projection lens. DETAILED DESCRIPTION

[0032] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0033] See also Figure 1 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0034] See also Figure 1 The present invention provides an optical path structure of an LCOS projection optical machine using a laser fluorescent ceramic light source, comprising a blue excitation light source array 1, a blue laser light source 2, a static fluorescent ceramic 6, a focusing collimating lens group 5, a light combining element 8, a polarization processing optical element 9, a color control optical group, a polarization beam splitting element 22, an LCOS 24 (Liquid Crystal on Silicon), and a projection lens 25;

[0035] The blue excitation light source array 1 is used to emit blue excitation light, and the blue laser light source 2 is used to emit blue laser light. In this embodiment, the blue laser light source 2 is a blue laser diode or a blue laser diode array, and the blue excitation light source array 1 is a blue laser diode array composed of a plurality of blue laser diodes.

[0036] The blue excitation light source array 1 is oppositely provided with a collimating lens array 3, wherein each blue laser diode in the blue excitation light source array 1 corresponds to a collimating lens, and the blue excitation light source array 1 emits blue excitation light through the collimating lens array 3, and the collimating lens array 3 is used to collimate the blue excitation light;

[0037] A first dichroic mirror 7 is disposed opposite the collimating lens array 3 and is used to reflect blue excitation light and transmit red and green mixed light. The first dichroic mirror 7 is located between the collimating lens array 3 and the focusing collimating lens group 5, and between the focusing collimating lens group 5 and the light combining element 8. The blue excitation light collimated by the collimating lens array 3 is incident on the first dichroic mirror 7, which reflects the blue excitation light to the focusing collimating lens group 5. The blue excitation light passes through the focusing collimating lens group 5, which focuses the blue excitation light onto the static fluorescent ceramic 6.

[0038] Blue excitation light is irradiated onto static fluorescent ceramic 6 to stimulate the generation of radiated fluorescence, wherein the radiated fluorescence is a mixed red and green light. In this embodiment, static fluorescent ceramic 6 is a copper-based fluorescent ceramic, which has excellent laser resistance and heat dissipation performance, and can improve the utilization rate of converting blue excitation light into a mixed red and green light. The red and green mixed light reflected by the copper-based fluorescent ceramic passes through a focusing collimating lens group 5 and is then collimated and expanded. After being collimated and expanded by the focusing collimating lens group 5, the red and green mixed light passes through a first dichroic mirror 7 and is irradiated onto a light combining element 8.

[0039] A collimating and beam expanding lens group 4 is arranged opposite to the blue laser light source 2. The collimating and beam expanding lens group 4 is used to collimate and expand the blue laser to have the same beam width as the expanded red and green mixed light;

[0040] The blue laser light source 2 emits a blue laser, which is expanded by the collimating and expanding lens group 4 and then incident on the light combining element 8. The light combining element 8 in this embodiment is a second dichroic mirror for transmitting the blue laser and reflecting the red and green mixed light. The blue laser incident on the second dichroic mirror passes through the second dichroic mirror, and the red and green mixed light incident on the second dichroic mirror is reflected. Then, the second dichroic mirror combines the blue laser and the red and green mixed light into mixed light and emits it.

[0041] The polarization processing optical element 9 is arranged opposite to the light combining element 8; the polarization processing optical element 9 in this embodiment is a linear polarizer; since the mixed light contains blue laser and red and green mixed light excited by the static fluorescent ceramic 6, the blue laser is polarized light, and the red and green mixed light is natural light rather than polarized light, and has a 360° polarization direction; the polarization direction of the blue laser in this embodiment is parallel to the transmission direction of the linear polarizer, and the blue laser can pass directly through the linear polarizer; while the red and green mixed light passes through the linear polarizer, the linear polarizer can filter out the light in the red and green mixed light with a polarization direction different from its transmission direction, and only allows the red and green mixed light parallel to the transmission direction of the linear polarizer to pass, thereby converting the mixed light passing through the linear polarizer into polarized light with the same polarization direction.

[0042] The color control optical group is used to separate polarized light into red, green, and blue lasers and transmit them separately. The color control optical group includes a color separation X prism 10, a color combination X prism 11, a first reflector 15, a second reflector 16, a third reflector 17, a fourth reflector 18, and three liquid crystal light valves; the three liquid crystal light valves are a first liquid crystal light valve 12, a second liquid crystal light valve 13, and a third liquid crystal light valve 14;

[0043] The color separation X prism 10 is disposed opposite to the linear polarizer, and the color combining X prism 11 is disposed opposite to the color separation X prism 10;

[0044] The first reflecting mirror 15 and the second reflecting mirror 16 are respectively arranged on both sides of the color separation X prism 10 and tilted toward the color combination X prism 11;

[0045] The third reflecting mirror 17 and the fourth reflecting mirror 18 are arranged on both sides of the color combining X prism 11 and are tilted toward the color separating X prism 10;

[0046] The first reflector 15 and the fourth reflector 18, the second reflector 16 and the third reflector 17 are arranged opposite to each other;

[0047] The first liquid crystal light valve 12 is disposed between the first reflector 15 and the fourth reflector 18, the second liquid crystal light valve 13 is disposed between the color separation X prism 10 and the color combination X prism 11, and the third liquid crystal light valve 14 is disposed between the second reflector 16 and the third reflector 17.

[0048] For example, polarized light is incident on the beam-splitting X-prism and is split into red light, green light, and blue laser light. The blue laser light is reflected by the beam-splitting X-prism onto the second reflector 16, then reflected by the second reflector 16 and passed through the third liquid crystal light valve 14 to be incident on the third reflector 17. After being reflected by the third reflector 17, it enters the color-combining X-prism 11. The red light passes through the beam-splitting X-prism and the second liquid crystal light valve 13 to enter the color-combining X-prism 11. The green light is also reflected by the beam-splitting X-prism onto the first reflector 15, then reflected by the second reflector 16 and passed through the first liquid crystal light valve 12 to be incident on the fourth reflector 18. After being reflected by the fourth reflector 18, it enters the color-combining X-prism 11.

[0049] The first liquid crystal light valve 12 , the second liquid crystal light valve 13 and the third liquid crystal light valve 14 are used to control the presence or absence of red light, green light and blue laser light and adjust the amount of red light, green light and blue laser light passing therethrough respectively.

[0050] A fifth reflector 19 is disposed opposite the color-combining X-prism 11, and a microlens array 20 is disposed opposite the fifth reflector 19. The light beam passing through the color-combining X-prism 11 is reflected by the fifth reflector 19 to the microlens array 20. The microlens array 20 is used to uniformly distribute the light spot, thereby uniforming the brightness of the projection image projected by the projection lens 25.

[0051] A relay lens group 21 is disposed opposite the microlens array 20, and a polarization beam splitter element 22 is disposed opposite the relay lens group 21. In this embodiment, the polarization beam splitter element 22 is a polarization beam splitter prism. The polarization beam splitter prism is used to separate the horizontal polarization and vertical polarization of a beam of light (red light, green light, or blue laser light), that is, to separate the horizontally polarized P light and the vertically polarized S light. The polarization beam splitter prism can reflect the S light and transmit the P light.

[0052] A compensation plate 23 is disposed opposite the polarization beam splitter prism. In this embodiment, the compensation plate 23 may be an achromatic quarter-wave plate for compensating for the phase deviation caused by the pre-tilt angle of the liquid crystal molecules in the LCOS 24, thereby improving the contrast of the image output by the optical machine. The compensation plate 23 is disposed opposite the LCOS 24. A projection lens 25 is disposed on a side of the polarization beam splitter prism away from the compensation plate 23. The projection lens 25 is disposed opposite the polarization beam splitter prism. After being compensated by the compensation plate 23, the light beam (red light, green light, or blue laser) is incident on the LCOS 24. The LCOS 24 modulates the polarization state of the light incident on each pixel thereon and reflects it. The reflected light passes through the polarization beam splitter prism. Since the polarization beam splitter prism transmits P light and reflects S light, the intensity of the light emitted from each LCOS pixel can be controlled. The light emitted from each pixel has a different intensity, thereby forming an image. Finally, the image is projected through the projection lens 25.

[0053] In summary, the static fluorescent ceramic 6 in the present invention is a copper-based fluorescent ceramic. Since copper-based fluorescent ceramics have excellent laser resistance and heat dissipation performance, the light energy of the blue excitation light can be increased by increasing the number of blue laser diodes in the blue excitation light source array 1 and increasing the power of a single blue laser diode, thereby enabling the copper-based fluorescent ceramic to convert high-energy red and green mixed light. The blue laser is supplemented by the blue laser light source 2, and then converted and processed by the light combining element 8, the polarization processing optical element 9, the color control optical group, the polarization beam splitting element 22, etc., so that high-brightness red light, green light, and blue laser light can be incident on the LCOS. After being modulated by the LCOS, it is emitted from the projection lens 25, thereby making the projection image of the projection machine have the characteristics of high brightness, and the projection machine can also form clear images even in bright environments. In addition, all the components used in the present invention are static, avoiding the use of a rotating phosphor as a wavelength conversion component and a rotating color wheel as a color control component. Static components have higher structural reliability and are suitable for high-reliability scenarios such as vehicle-mounted and airborne applications where the use of rotating components is not allowed.

[0054] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. An optical path structure of an LCOS projector using a laser fluorescent ceramic light source, characterized by: include A blue excitation light source array (1), the blue excitation light source array (1) is used to emit blue excitation light; a blue laser light source (2), the blue laser light source (2) is used to emit blue laser light; A collimating lens array (3) for collimating blue excitation light; A collimating and beam expanding lens group (4) is used to collimate and expand the blue laser to a desired size; A static fluorescent ceramic (6) is provided with a focusing collimating lens group (5) between the blue excitation light source array (1) and the static fluorescent ceramic (6), wherein the focusing collimating lens group (5) is used to focus the blue excitation light on the static fluorescent ceramic (6); the blue excitation light is converted into red and green mixed light by the static fluorescent ceramic (6) and then emitted and collimated and expanded after passing through the focusing collimating lens group (5); a first dichroic mirror (7) for reflecting blue excitation light and transmitting red and green mixed light; The light combining element (8) is a second dichroic mirror for transmitting the blue laser and reflecting the red and green mixed light, and is used to combine the blue laser and the red and green mixed light into mixed light and then emit the mixed light; a polarization processing optical element (9), wherein the polarization processing optical element (9) is used to convert the mixed light into polarized light; A color control optical group is used to separate polarized light into red, green, and blue lasers, and then control the passage or cutoff of the red, green, and blue lasers respectively, and finally combine the red, green, and blue lasers into one output without changing their polarization state and polarization direction at the time of incidence; A polarization beam splitting element (22), the polarization beam splitting element (22) being used to reflect red light, green light, and blue laser light in a vertical polarization direction and transmit red light, green light, and blue laser light in a horizontal polarization direction; LCOS (24), wherein the LCOS (24) is used to modulate the polarization state of red light, green light, and blue laser light in the same polarization direction and then reflect the modulated light to the projection lens (25); The collimating lens array (3) is located between the blue excitation light source array (1) and the focusing collimating lens group (5); the first dichroic mirror (7) is located between the collimating lens array (3) and the focusing collimating lens group (5), and between the focusing collimating lens group (5) and the light combining element (8); the collimating beam expanding lens group (4) is located between the blue laser light source (2) and the light combining element (8); the static fluorescent ceramic (6) is a copper-based fluorescent ceramic; and the polarization processing optical element (9) is a linear polarizer.

2. The optical path structure of an LCOS projector using a laser fluorescent ceramic light source according to claim 1, characterized in that: The color control optical group includes a color separation X prism (10), a color combination X prism (11), a first reflector (15), a second reflector (16), a third reflector (17), a fourth reflector (18), and three liquid crystal light valves; The color separation X prism (10) is arranged opposite to the linear polarizer, and the color combining X prism (11) is arranged opposite to the color separation X prism (10); The first reflector (15) and the second reflector (16) are respectively arranged on both sides of the color separation X prism (10) and are inclined toward the color combination X prism (11); The third reflector (17) and the fourth reflector (18) are arranged on both sides of the color combining X prism (11) and are inclined toward one side of the color separating X prism (10); The first reflector (15) and the fourth reflector (18), the second reflector (16) and the third reflector (17) are arranged opposite to each other; The three liquid crystal light valves are respectively arranged between the first reflecting mirror (15) and the fourth reflecting mirror (18), the color separation X prism (10) and the color combination X prism (11), the second reflecting mirror (16) and the third reflecting mirror (17).

3. The optical path structure of an LCOS projector using a laser fluorescent ceramic light source according to claim 2, characterized in that: It also includes a fifth reflector (19) arranged opposite to the color-combining X-prism (11), and a microlens array (20) and a relay lens group (21) are arranged between the fifth reflector (19) and the polarization beam splitting element (22).

4. The optical path structure of an LCOS projector using a laser fluorescent ceramic light source according to claim 3, characterized in that: The polarization beam splitting element (22) is a polarization beam splitting prism, and a compensation plate (23) is provided between the polarization beam splitting prism and the LCOS (24).

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