WO2011029294A1 - Laser display light source and laser display system - Google Patents

Abstract

A laser display light source and a laser display system are provided by the present invention. Said laser display light source includes a pump source for emitting pump light; a laser crystal and a group of periodically-poled crystals both in a resonator. Said group of periodically-poled crystals includes at least one periodically-poled crystal; said laser crystal receives the pump light emitted from the pump source and emits laser; said group of periodically-poled crystals receives the laser emitted by the laser crystal as the fundamental frequency light, and emits high-order harmonic light; the periodically-poled duty cycle and the crystal length of said poled crystals are determined according to the light intensity of the high-order harmonic light; the poled period of the periodically-poled crystals is determined according to the wavelength of the high-order harmonic light. Said laser display system includes said laser display light source, an optical engine and an imaging unit. The present invention provides the laser display light source and the laser display system, which are compact and energy saving, thus convenient for industrilization.

Description

 A laser display light source and a laser display system The present application claims priority to Chinese Patent Application No. 200910170877.4, entitled "A Laser Display Light Source and Laser Display System", filed on September 11, 2009, by the Chinese Patent Office. The entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The present invention relates to the field of laser display, and more particularly to a laser display light source and a laser display system. BACKGROUND OF THE INVENTION Laser display technology has the characteristics of large color gamut and low energy consumption, and is considered to be the next generation mainstream display technology. In order to promote laser display technology, the development of compact laser sources is particularly important. The laser light source for laser display needs to provide three primary color light output. At present, the red light in the three primary colors is formed by the semiconductor laser output light beam, and the green light and blue light are filtered by the infrared semiconductor laser to the solid laser crystal through nonlinear optics. The crystal is multiplied. The laser light source module of such a structure is composed of separate three-primary color modules, which is large in volume and high in energy consumption, and is inconvenient for display system design, and limits the application of laser display technology in many fields. In order to solve the above problems, different principles and methods are applied to enable a laser module to output two-color or multi-color light. For example, an output of a three-color light is disclosed in the Chinese Patent Application Publication No. CN101232149, the disclosure of which is incorporated herein by reference. s installation. The three primary colors in the device are generated in three separate resonant units, and the structure is still not compact enough. A solid state laser is disclosed in U.S. Patent No. 6,671,305 B2, issued on Dec. 30, 2003, entitled "Solid State Laser", which utilizes frequency doubling, sum frequency and optical parametric processes. The mixing produces a three primary color light output. However, there are many steps in the variation of the optical frequency in the laser, and the internal structure of the laser is too complicated.

Summary of the invention In view of this, an object of the present invention is to provide a laser display light source and a laser display system, which can effectively save the volume of the laser light source module and reduce energy consumption.

 To achieve the above object, the present invention provides a laser display light source, comprising: a pump source for outputting pump light, and a laser crystal located in the resonant cavity and combined with a periodically polarized crystal, the periodic polarization The crystal combination includes at least one periodically polarized crystal for receiving pump light output by the pump source and outputting a laser, the periodically polarized crystal combination for receiving laser light output from the laser crystal As the fundamental light, and outputting multi-order frequency doubling light, the periodic polarization duty ratio and the crystal length of the periodically polarized crystal are determined according to the light intensity of the multi-order frequency doubling light, the periodicity The polarization period of the polarized crystal is determined according to the wavelength of the multi-order frequency doubling light.

 Preferably, the multi-order frequency doubling light comprises any combination of first order frequency doubling light, second order frequency doubling light and third order frequency doubling light.

 Preferably, the plurality of periodically polarized crystals are fixed together without being spaced apart from each other in the direction of light propagation. This can further reduce the volume of the light source module.

 Preferably, a filter for filtering out unwanted multiplier light is provided outside the laser output end of the cavity of the laser display source. This will filter out unwanted multiplier light.

 Preferably, the periodically polarized crystal is a periodically poled lithium niobate crystal or periodically poled potassium titanyl phosphate.

 Preferably, the pumping source uses a laser diode having an output light wavelength of 808 nm.

 Preferably, the laser crystal is a Nb:YV04, Nb:YAG or Nb:GaV04 crystal.

 Preferably, the resonant cavity is a straight cavity, an L-shaped cavity, a Z-shaped cavity or an annular cavity.

 Preferably, the form of the periodically polarized crystal is a block structure or a waveguide structure.

 Further, the present invention provides a laser display system comprising the above laser display light source, an optical engine and an imaging unit.

Preferably, the pumping source in the laser display source uses a laser diode having an output light wavelength of 808 nm, and the laser crystal is a Nb:YV04, Nb:YAG or Nb:GaV04 crystal. The laser display light source provided in this embodiment only needs to utilize a single periodically polarized crystal device. Compared with the prior art, the entire light source module has a compact structure, can effectively save the volume of the light source module, and reduce energy consumption, so that the laser display light source is more favorable for industrialization. At the same time, the volume and power consumption of the laser display system using the light source module are also reduced accordingly. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, in the following description The drawings are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work. 1 is a schematic diagram of a laser display light source according to a first embodiment of the present invention; FIG. 2 is a schematic diagram of a laser display light source using an L-shaped resonant cavity according to Embodiment 1 of the present invention; FIG. 4 is a schematic diagram of a laser display light source according to Embodiment 3 of the present invention; and FIG. 5 is a schematic diagram of a laser display system according to Embodiment 5 of the present invention. The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. The embodiments are a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without departing from the inventive scope are the scope of the present invention. Embodiment 1 FIG. 1 is a schematic view showing a laser display light source according to Embodiment 1 of the present invention. As shown in FIG. 1, the laser display light source includes a pump source 1 and a resonance defined by the mirrors 4 and 5 together. a cavity 7, a laser crystal and a periodic polarization crystal comprising at least one periodically polarized crystal are disposed in the cavity 7 Body combination 3.

 Among them, the pump light generated by the pump source 1 is input to the laser crystal 4 as an excitation, and the laser crystal 4 outputs a laser light under the excitation of the pump light. In Fig. 1, in particular, the pump light generated by the pump source 1 is incident on the laser crystal 2 from the cavity mirror 4. It will be understood by those skilled in the art that the laser crystal 4 can be pumped with a medium and small power end face pump. Pu or high power side pumping, for example, in Fig. 1, in particular, end pumping is taken as an example. The pump source 1 can be either a laser diode (LD) or another type of pump source. A laser diode having an output light wavelength of 808 nm is preferably used in this embodiment. In order to enable the pump light output from the pump source 1 to be sufficiently incident into the laser crystal 2, preferably, a focusing assembly 6 is provided between the pump source 1 and the laser crystal 2 for focusing the pump light. Then input it into the laser crystal 2. Focusing assembly 6 can be a common combination of lenses.

 The laser output from the laser crystal 2 is input to a periodically polarized crystal combination 3 of at least one periodically polarized crystal, and all of the periodically polarized crystals are arranged in series in the direction of light propagation. In the periodic polarization crystal combination 3, the output laser of the laser crystal 2 is used as the fundamental light, and the laser is subjected to a nonlinear effect in the periodically polarized crystal to realize quasi-phase matching and generate multi-order frequency doubled light. Specifically, when the output laser of the laser crystal 2 sequentially passes through each of the periodically polarized crystals in the periodically polarized crystal combination 3 along the light propagation direction, a multi-order multiple corresponding to the periodically polarized crystal is generated. Frequency light, and the wavelength of each order multiplied light generated by each periodically polarized crystal is related to the polarization period Λ of the periodically polarized crystal (or can be expressed as: when the fundamental wavelength of the light is known, The polarization period of the periodically polarized crystal determines the wavelength of each order frequency doubling light, and the intensity of each order multiplied light generated by each periodically polarized crystal and the periodic pole of the periodically polarized crystal The duty cycle ξ is related to the crystal length. The laser crystal 2 may preferably be a solid laser crystal such as Nb:YV04, Nb:YAG or Nb:GaV04 crystal. The periodically polarized crystal is preferably a PPLN (periodicly poled lithium niobate) crystal or a PPKTP (periodic polar potassium titanyl phosphate) crystal.

The following explains in detail how the polarization period Λ and the periodic polarization duty ratio 周期性 of the periodically polarized crystal affect the wavelength and intensity of the output octave light. When the wavelengths of the two fundamental lasers input to the periodically polarized crystal are respectively λ ₂ , from the week M-th frequency wavelength of polarized light output from the crystal satisfies the following equation [lambda] between the fundamental frequency of the laser ₂₃ and the wavelength λ:

(Gezi 1)

When the wavelengths of the two fundamental lights are the same (both λ), the above formula 1 can be rewritten as:

 n 2n, m

t = ⁺ (Formula ²⁾ where is the refractive index of the light of the wavelength in the periodically polarized crystal, n ₂ is the refractive index of the light of the wavelength λ ₂ in the periodically polarized crystal, and η ₃ is the wavelength The refractive index of λ ₃ in periodically polarized crystals, and it should be understood by those skilled in the art in conjunction with common general knowledge that since the refractive index is a function of wavelength (which can be derived by the dispersion relationship of periodically polarized crystalline materials), Given the material of the periodically polarized crystal and the period of polarization, the wavelength of each order of frequency doubling light can be uniquely determined according to Equation 1. Unlike birefringence phase matching, the quasi-phase matching technique of periodically polarized crystals does not have to be one-half the wavelength of the fundamental light, which can extend the choice of crystal and optical wavelengths. Achieve full wavelength coverage.

For example, when the laser crystal 2 in FIG. 1 is a Nb:YV04 crystal, and the pump source 1 is a laser diode having an output light wavelength of 808 nm, the laser output from the laser crystal 2 is an infrared having a wavelength of 1064 nm or 1342 nm. laser. Thus, the fundamental frequency light of each periodically polarized crystal in the periodically polarized crystal combination 3 is an infrared laser having a wavelength of 1064 nm or 1342 nm. For example, when a periodically polarized crystal is a PPLN (periodicly polarized tantalum 4) crystal, if the output laser wavelength of the laser crystal 2 is 1064 nm, the fundamental wavelength of the PPLN crystal is 1064 nm, and the fundamental light is After passing through a PPLN crystal having a polarization period of 4.277 μm, the wavelength of the first-order frequency doubling light is 525 nm, the wavelength of the second-order frequency doubling light is 495 nm, and the wavelength of the third-order frequency doubling light is 470 nm. If the laser wavelength of the laser crystal 2 is 1342 nm, a PPLN crystal with a polarization period of 2.137 μm is used. When the crystal is periodically polarized, the first-order frequency-doubled light has a wavelength of 610 nm, the second-order frequency-doubled light has a wavelength of 525 nm, and the third-order frequency-doubled light has a wavelength of 470 nm. Of course, it is also possible to have the laser crystal 2 simultaneously output two wavelengths of laser light as two fundamental frequency lights, but not every laser input of a wavelength to a periodically polarized crystal having any one polarization period can achieve quasi-phase matching. Because, for a periodically polarized crystal with a specific polarization period value, only a very narrow wavelength range of fundamental light can achieve quasi-phase matching in the periodically polarized crystal, and output each order of frequency doubling light. For example, in a PPLN crystal with a polarization period of 4.277 μm, only the fundamental light having a wavelength in the vicinity of 1064 nm can be input to the crystal to output a frequency-doubled light; and for a PPLN crystal having a polarization period of 2.137 μm, only The fundamental frequency light having a wavelength in the vicinity of 1342 nm is input to the crystal, and the frequency doubled light can be output. In summary, the wavelength of each order frequency doubling light can be selected by selecting the material of the periodically polarized crystal and the polarization period ,. In practice, the periodic polarization used can be determined according to the wavelength of each order light required. The material, number and period of polarization of the crystal. For example, in an actual laser display device, it is necessary to provide a light source device capable of outputting output light of three primary colors. Therefore, when the wavelength of the fundamental light is 1342 nm, first-order frequency doubling light, second-order frequency doubling light, and third order can be generally used. The frequency doubled light is output as three primary colors. On the other hand, the periodic polarization duty cycle 周期性 of the periodically polarized crystal determines the intensity of each order multiplied light output from the periodically polarized crystal. The intensity of each order octave light is proportional to the square of the respective electrical vector magnitude, and the magnitude of the electrical vector is proportional to the quasi-phase matching (QPM) effective nonlinear coefficient D. The expression of the QPM effective coefficient of each order of frequency doubling light is as follows:

(Expression 3)

In equation 3, m is the frequency multiplication order, ξ is the periodic polarization duty cycle, and d _{eff is} the effective nonlinear coefficient determined by the crystal characteristics. For each periodically polarized crystal, d _eff is constant. It can be seen that the intensity of each order frequency doubling light and the periodic polarization duty ratio of the periodically polarized crystal are known under the premise that the periodically polarized crystal material and the polarization period Λ are known. related. For example, for a PPLN crystal with a polarization period of 4.277 μm, if the periodic polarization duty is 50%, the intensity of the second-order frequency doubling light with a wavelength of 495 nm is 0, and the output wavelength is 525 nm. The light intensity ratio of the frequency doubling light to the third order frequency doubling light having a wavelength of 470 nm is 9:1. For a PPLN crystal with a polarization period of 2.137 μm, if the periodic polarization duty ratio is 25%, the intensity ratio of the first-order frequency doubling light with a wavelength of 61 Onm and the second-order frequency doubling light with a wavelength of 525 nm is output. For 2: 1.

 In summary, when the material of the periodically polarized crystal and the polarization period Λ are known, the selection of the intensity of the output of the multiplied light can be achieved by selecting different periodic polarization duty cycles ξ.

 In addition, the output light intensity of each order doubled light is also proportional to the square of the length of the periodically polarized crystal. When there are a plurality of periodically polarized crystals in the periodically polarized crystal combination 3, all of the periodically polarized crystals may be arranged along the optical path at a certain distance from each other, and of course, may be spaced apart from each other in the direction along the optical path. Fixed together. In this embodiment, it is preferable to fix a plurality of periodically polarized crystals without spaces, which can further improve the compactness of the entire light source module and further reduce the volume.

 In order to prevent part of the fundamental frequency light generated by the laser crystal from being output from the resonant cavity, the output light performance of the subsequent light source is excessively affected. In practice, the two cavity mirrors that limit the resonant cavity can be designed as a pair in the present embodiment. The frequency light is all reversed or high reversed, so that not only the external leakage of the fundamental light can be reduced, but also the fundamental frequency light can be fully oscillated in the resonant cavity, and the output intensity of the frequency-doubled light of the entire light source is improved.

In the present embodiment, it is preferable to provide a filter for filtering out unnecessary frequency-doubled light in an optical path outside the laser output end of the resonant cavity 7 (the output end of the cavity mirror 5 side in Fig. 1). For example, by setting a corresponding filter, the multiplier light whose wavelength does not fall within the wavelength range of red, green, and blue is filtered out. In addition, it should be noted that the wavelengths of the red, green and blue light of the three primary light sources generally take the following preferred ranges: red light wavelength is 605 ± 5 nm, green light wavelength is 530 ± 10 nm, and blue light wavelength is preferably 470 ± 10 nm. Under the constraints of the above range, although the wavelength of some light is divided into one of the three colors of light from the spectral angle, the wavelength does not fall within the above range. For example, the fundamental frequency of 1064 nm is incident on the polarization period of 4.277 μm. After the PPLN crystal, the second-order frequency doubling light with a wavelength of 495 nm is green light from the perspective of the spectrum, but since the wavelength is not in the range of 530 ± 10 nm, it is usually not used as a green light source for the three primary color light sources. Therefore, in practice, it is necessary to design the periodic polarization duty cycle of the PPLN crystal or A filter capable of filtering out the light of the wavelength is provided to make the output of the frequency doubled light having a wavelength of 495 nm zero. However, in a light source having a wider color gamut of four primary colors or even five primary colors, the above-mentioned 495 nm green light can still be retained.

In addition, the shape of the cavity shown in FIG. 1 is a straight cavity, and in fact, the shape of the cavity may be an L-shaped cavity, a Z-shaped cavity or an annular cavity. For example, an L-shaped resonant cavity as shown in FIG. 3 is employed. The pump source is not shown in Fig. 3. The laser light source using the L-shaped resonator shows that the light source is no longer a straight line, and a mirror for changing the direction of the light path is added between the laser crystal 2 and the periodically polarized crystal 3. 8. Compared to the straight cavity shown in Figure 1, the L-shaped cavity and other forms of cavity facilitate the optimization of the beam size of the laser crystal and the beam size of the frequency doubling crystal. In practice, the form of the periodically polarized crystal may be a block structure or a waveguide structure. Since the laser display source provided by the embodiment only needs to use a single periodically polarized crystal device to output multi-order frequency doubling light, for example, a red, green, and blue color laser, and of course, a laser of more primary colors. And by selecting the periodic polarization duty cycle of the periodically polarized crystal, the selection of the output light intensity of each order of frequency doubling light can be achieved. Compared with the prior art, the entire light source module has a compact structure, can effectively save the volume of the light source module, and reduce energy consumption, so that the laser display light source is more favorable for industrialization. In the laser display, in order to achieve the desired white balance, there is a specific requirement for the light intensity ratio of the red, green and blue color output light of the light source, for example, the light intensity ratio of the red, green and blue light is 1:6:3. When the desired intensity ratio of red, green and blue light is known, the material of the periodically polarized crystal can be flexibly selected, the number, the period of polarization, and the periodic polarization duty cycle ξ, so that the output is red. The light intensity ratio of green and blue light meets the required requirements. The required white balance is different, and the setting of the laser display light source is also adjusted accordingly. The following is exemplified by several specific embodiments. Embodiment 2 In this embodiment, the required white balance requires that the light intensity ratio of the red, green and blue light is 3:6:1. As shown in FIG. 3, the pump source 1 in the laser display light source in this embodiment uses a laser diode having an output light wavelength of 808 nm, and the laser crystal 2 is a Nb:YV04 crystal, and the periodically polarized crystal combination 3 includes Two periodically polarized crystals, each using a PPLN crystal, have polarization periods of 4.277 micrometers and 2.137 micrometers, respectively. During the operation of the laser display source, the laser crystal 2 generates infrared lasers having wavelengths of 1064 nm and 1342 nm, respectively. In the process of the two wavelengths of infrared laser passing through the periodically polarized crystal combination 3, the infrared laser having a wavelength of 1064 nm passes through. Quasi-phase matching is achieved when the PPLN crystal with a polarization period of 4.277 μm is generated, the first-order frequency doubling light wavelength is 525 nm, the second-order frequency doubling light wavelength is 495 nm, the third-order frequency doubling light wavelength is 470 nm, and the wavelength is 1342 nm. The infrared laser achieves quasi-matching matching when passing through a PPLN crystal with a polarization period of 2.137 microns. The first-order frequency doubling light has a wavelength of 610 nm, the second-order frequency doubling light has a wavelength of 525 nm, and the third-order frequency doubled light has a wavelength of 470. As described above, in the present embodiment, the polarization periods of the two PPLN crystals constituting the periodic polarization crystal combination are different, but the duty ratio of the periodic polarization is 50%. Theoretical calculation can be made: When a 1064 nm infrared laser is input to a PPLN crystal having a polarization period of 4.277 μm and a periodic polarization duty ratio of 50%, the first-order frequency doubling light (wavelength is 525 nm, belonging to the green light range) and second-order magnification are generated. The ratio of light intensity between light (wavelength 495 nm, belonging to the green range) and third-order frequency doubling (wavelength 470 nm, belonging to the blue range) is 9:0:1, so that the period from the polarization period is 4.277 μm. The ratio of the intensity of green light to blue light output from a PPLN crystal with a 50% duty cycle is 9:1. In practice, since the preferred wavelength of green light in the three primary color light source is 530 ± 10 nm, the wavelength of the second-order frequency doubled light is in the green light range from the perspective of the spectrum, but is not normally used as a three primary color light source in practice. The green light source is used, so in this embodiment, by selecting the periodic polarization duty ratio of the specific PPLN crystal, the output light intensity of the wavelength of the wavelength is zero. However, in a light source having a wider color gamut of four primary colors or even five primary colors, the above-mentioned 495 nm green light can still be retained. When an infrared laser with a wavelength of 1342 nm is input to a PPLN crystal having a polarization period of 2.137 μm and a periodic polarization duty ratio of 50%, a first-order frequency doubling light (wavelength of 610 nm, belonging to the red light range) is generated. The ratio of the light intensity between the order frequency doubling light (wavelength is 525 nm, which belongs to the green light range) and the third-order frequency doubling light (wavelength of 470 nm, belonging to the blue light range) is 9:0:1, so that the polarization period is 2.137. Micro The ratio of the intensity of red and blue light output from a PPLN crystal with a periodic polarization duty cycle of 50% is 9:1. Since the intensity of the output frequency doubling light is proportional to the square of the length of the periodically polarized crystal, when the intensity of the two fundamental lights (i.e., infrared lasers having wavelengths of 1064 nm and 1342 nm, respectively) is the same, only the above polarization needs to be made. The ratio of the length of the PPLN crystal with a period of 4.277 μm and a periodic polarization duty ratio of 50% to the length of the PPLN crystal with a polarization period of 2.137 μm and a periodic polarization duty ratio of 50% is equal to 7Ϊ, which is the final The light intensity ratio between red, green, and blue light output from the laser display source is 3:6:1.

Embodiment 3 In the present embodiment, the required white balance still requires that the light intensity ratio of the red, green and blue light is 3:6:1. FIG. 4 shows a schematic diagram of the laser display light source provided by the embodiment. The difference between this embodiment and the second embodiment is that the periodic polarization duty ratios of the two PPLN crystals constituting the periodically polarized crystal combination 3 are different. The polarization periods of the two PPLN crystals used in this embodiment are still 2.137 microns and 4.277 microns, but the periodic polarization duty cycles are 22% and 46%, respectively. Theoretical calculations can be made: When the infrared laser with a wavelength of 1342 nm is input to a PPLN crystal with a polarization period of 2.137 μm and a periodic polarization duty ratio of 22%, the first-order frequency doubling light (wavelength is 610 nm, The ratio of the light intensity between the second-order frequency doubling light (wavelength of 525 nm, belonging to the green light range) and the third-order frequency doubling light (wavelength of 470 nm, belonging to the blue light range) is 5:3:1. Thus, the ratio of the intensity of red, green, and blue light output from a PPLN crystal having a polarization period of 2.137 μm and a periodic polarization duty ratio of 22% is 5:3:1. When an infrared laser with a wavelength of 1064 nm is input to a PPLN crystal having a polarization period of 4.277 μm and a periodic polarization duty ratio of 46%, a first-order frequency doubling light (wavelength of 525 nm, belonging to the green light range) is generated. The ratio of the light intensity between the order frequency doubling light (wavelength 495 nm, belonging to the green light range) and the third-order frequency doubling light (wavelength 470 nm, belonging to the blue light range) is 10:0.2:1, so that the polarization period is The P277 crystal output of a 4.277 micron, periodic polarization duty cycle of 46% has a ratio of green to blue light as a three primary color source of 10:1. It should be noted that the preferred wavelength of green light in the three primary color light source is 530 ± 10 nm, so the wavelength of the above-mentioned second-order frequency doubling light belongs to the green light range from the perspective of the spectrum, but it is not normally used as the green light source of the three primary color light source, so that 0.2 of the output from the PPLN crystal is used. The proportion of the second-order frequency doubling light needs to be filtered out, and can be achieved by setting a filter capable of filtering out light of 495 nm wavelength. However, in a light source having a wider color gamut of four primary colors or even five primary colors, the above-mentioned 495 nm green light can still be retained. Since the intensity of the output frequency doubling light is proportional to the square of the length of the periodically polarized crystal, when the intensity of the two fundamental lights (i.e., infrared lasers having wavelengths of 1064 nm and 1342 nm, respectively) is the same, only the above polarization needs to be made. The ratio of the length of the PPLN crystal with a period of 2.137 μm and a periodic polarization duty ratio of 22% to the length of the PPLN crystal with a polarization period of 4.277 μm and a periodic polarization duty ratio of 46% is equal to VT? The final laser display shows a light intensity ratio of 3:6:1 between red, green and blue light.

 Embodiment 4 In this embodiment, the required white balance requires that the light intensity ratio of the red, green and blue light is still 3:6:1. The laser display light source provided by this embodiment differs from the third embodiment in that: the laser crystal outputs only one fundamental frequency light, that is, an infrared laser having a wavelength of 1342 nm, and the periodically polarized crystal combination 3 includes two periodically polarized crystals. They are PPLN crystals with a polarization period of 2.137 μm, a periodic polarization duty cycle of 19%, and a polarization period of 0.953 μm and a periodic polarization duty cycle of 50%.

 Through theoretical calculations, it can be concluded that when the infrared laser with a wavelength of 1342 nm is input to a PPLN crystal with a polarization period of 2.137 μm and a periodic polarization duty cycle of 19%, respectively, the first-order frequency doubling light (wavelength is 610 nm) is generated. The ratio of the light intensity between the second-order frequency doubling light (wavelength of 525 nm, belonging to the green light range) and the third-order frequency doubling light (wavelength of 470 nm, belonging to the blue light range) is 3:2:1 Thus, the ratio of the intensity of red, green, and blue light output from a PPLN crystal having a polarization period of 2.137 μm and a periodic polarization duty ratio of 19%, respectively, is 3:2:1.

When an infrared laser with a wavelength of 1342 nm is input to a PPLN crystal having a polarization period of 0.953 μm and a periodic polarization duty ratio of 50%, the first-order frequency doubling light is generated at a wavelength of 525 nm, belonging to the green light range, second order. The intensity of the frequency-doubled light is zero, and the wavelength of the third-order frequency doubled light is already outside the visible light. Thus, the red output of the PPLN crystal with a polarization period of 0.953 μm and a periodic polarization duty ratio of 50% The ratio of the light intensity of green and blue light is 1:0:0. Since the intensity of the output frequency doubling light is proportional to the square of the length of the periodically polarized crystal, it is only necessary to make the PPLN crystal with a polarization period of 2.137 μm and a periodic polarization duty ratio of 19% and a polarization period of 0.953. The ratio of the length of the PPLN crystal with a micron, periodic polarization duty cycle of 50% is equal to 2.5, so that the light intensity ratio between red, green and blue light output from the final laser display source is 3:6:1.

 Embodiment 5 This embodiment provides a laser display system. As shown in FIG. 5, the laser display system includes: a laser display source 21, an optical engine 22, and an imaging unit 23. The laser display light source 21 adopts any one of the above-mentioned first embodiment to the fourth embodiment, and details are not described herein again. The laser display source 21 is configured to output multi-order frequency-doubled light; the optical engine 22 is configured to receive the multi-order frequency-doubled light output by the laser display source 21, and modulate the multi-order frequency-doubled light according to the input image coded signal, and output The modulated optical signal; the imaging unit 23 is configured to receive the modulated optical signal output by the optical engine 22 and perform imaging display. Specifically, the laser display source 21 outputs a multi-primary laser (eg, three primary colors) that meets predetermined requirements into the optical engine 22, and the optical engine 22 may include a device that combines the multiple primary lasers, a shimming device, and an input according to The image coding signal is a light modulation device that modulates the multi-primary laser light, and the imaging unit 23 is configured to image-display the laser light output from the optical engine 22.

 Since the light source module of the laser display system in the embodiment has a compact structure, the volume of the light source module can be effectively saved, energy consumption is reduced, and the volume and energy consumption of the entire display system are correspondingly reduced.

 The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

Rights request

 What is claimed is: 1. A laser display light source, comprising: a pump source for outputting pump light, and a combination of a laser crystal and a periodically polarized crystal located in a resonant cavity, the periodically polarized crystal combination comprising At least one periodically polarized crystal for receiving pump light output by the pump source and outputting laser light, the periodically polarized crystal combination for receiving laser light output from the laser crystal as a fundamental frequency Light, and outputting multi-order frequency doubling light, wherein a periodic polarization duty ratio and a crystal length of the periodically polarized crystal are determined according to a light intensity of the multi-order frequency doubling light, the periodically polarized crystal The polarization period is determined based on the wavelength of the multi-order frequency doubling light.

 The laser display light source according to claim 1, wherein the plurality of periodically polarized crystals are fixed together without being spaced apart from each other in a light propagation direction.

 3. A laser display source according to claim 1, wherein a filter is provided outside the laser output end of the cavity of the laser display source, the filter for filtering out unwanted multiplier light.

 The laser display light source according to claim 1, wherein the periodically polarized crystal is a periodically poled lithium niobate crystal or a periodically poled potassium titanyl phosphate crystal.

 The laser display light source according to any one of claims 1 to 4, wherein the pump light source is a laser diode having an output light wavelength of 808 nm.

 The laser display light source according to claim 5, wherein the laser crystal is Nb: YV04, Nb: YAG or Nb: GaV04 crystal.

 The laser display light source according to any one of claims 1 to 4, wherein the resonant cavity is a straight cavity, an L-shaped cavity, a Z-shaped cavity or an annular cavity.

 The laser display light source according to any one of claims 1 to 4, wherein the form of the periodically polarized crystal is a block structure or a waveguide structure.

A laser display system, comprising: the laser display light source according to any one of claims 1 to 4, an optical engine and an imaging unit, wherein the laser display light source is for outputting multi-order frequency-doubled light; The optical engine is configured to receive multi-order frequency-doubled light output by the laser display light source, and modulate the multi-order frequency-doubled light according to the input image encoded signal, and output the modulated optical signal; The imaging unit is configured to receive the modulated optical signal output by the optical engine and perform imaging display.

The laser display system according to claim 9, wherein the pump light source in the laser display source uses a laser diode having an output light wavelength of 808 nm, and the laser crystal is Nb: YV04, Nb: YAG. Or Nb: GaV04 crystal.