CN113805417A

CN113805417A - Projection display system

Info

Publication number: CN113805417A
Application number: CN202010535362.6A
Authority: CN
Inventors: 余新; 郭祖强; 胡飞; 陈晨; 龚晨晟; 鲁宁
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2020-06-12
Filing date: 2020-06-12
Publication date: 2021-12-17
Also published as: WO2021249511A1

Abstract

The application discloses a projection display system, which comprises a light source component, a wavelength adjusting component and a modulating component, wherein the light source component is used for emitting projection light; the wavelength adjusting component is used for receiving the projection light and adjusting the spectrum of the projection light so as to improve the luminous efficiency of the projection light; the modulation component is arranged on the emergent light path of the wavelength adjusting component and is used for carrying out image modulation on the light emergent from the wavelength adjusting component to obtain corresponding image light so as to form a projection image. Through the mode, the luminous efficacy of the projection light can be improved, and therefore the display brightness is improved.

Description

Projection display system

Technical Field

The application relates to the technical field of display, in particular to a projection display system.

Background

In the existing projection system, in order to improve the light energy utilization rate of a light source, a common design logic is to reduce light loss in the light splitting and combining process and use the fluorescence excited by laser as much as possible, the spectrum of the fluorescence obtained in this way is generally wider, so that the light visibility of the projection system is lower, and the brightness of a white field which can be displayed is lower under the condition of a certain thermal load of a spatial light modulator.

Disclosure of Invention

The application provides a projection display system, can improve the luminous efficacy of projection light to improve and show luminance.

In order to solve the technical problem, the technical scheme adopted by the application is as follows: there is provided a projection display system comprising: the light source assembly is used for emitting projection light; the wavelength adjusting component is used for receiving the projection light and adjusting the spectrum of the projection light so as to improve the luminous efficiency of the projection light; the modulation component is arranged on the emergent light path of the wavelength adjusting component and is used for carrying out image modulation on the light emergent from the wavelength adjusting component to obtain corresponding image light so as to form a projection image.

Through above-mentioned scheme, this application's beneficial effect does: the wavelength adjusting component with wavelength selection characteristics is added in the projection display system, the wavelength adjusting component is positioned in a light path in front of the modulation component for regulating and controlling the projection light, the wavelength adjusting component can adjust the spectral characteristics of light beams incident on the modulation component so as to improve the luminous efficacy of the projection light, the effect of improving the brightness of the emergent flow under the condition that the thermal load of the modulation component is not obviously changed is realized, and the display brightness can be improved under the condition that the thermal load of the modulation component is not increased.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:

FIG. 1 is a graph illustrating spectral luminous efficiency curves under photopic vision;

FIG. 2 is a schematic diagram of the tristimulus value curve of CIE1931XYZ standard;

FIG. 3 is a schematic view of an area illuminated by incident light on a DMD;

FIG. 4 is a schematic structural diagram of a projection display system according to a first embodiment of the present disclosure;

FIG. 5 is a Rec.709 standard color gamut map;

FIG. 6 is a schematic diagram of the color coordinates of the adjusted green primary light in the embodiment shown in FIG. 4;

FIG. 7 is a schematic diagram of the projection display system of the embodiment shown in FIG. 4;

FIG. 8 is a schematic diagram of another embodiment of the projection display system shown in FIG. 4;

FIG. 9 is a schematic diagram of another embodiment of the projection display system shown in FIG. 4;

FIG. 10 is a schematic diagram of a second embodiment of a projection display system according to the present application;

FIG. 11 is a graph showing a normalized spectrum of green fluorescence in the example shown in FIG. 10;

FIG. 12 is a schematic diagram of a projection display system according to a third embodiment of the present application;

FIG. 13 is a schematic diagram of a projection display system according to a fourth embodiment of the present application;

FIG. 14 is a schematic diagram of a fifth embodiment of a projection display system according to the present application;

FIG. 15(a) is a schematic diagram of the laser fluorescence spectrum in the embodiment shown in FIG. 14;

FIG. 15(b) is a schematic diagram of the laser fluorescence spectrum of FIG. 15(a) after being adjusted using a filter;

FIG. 16 is a schematic diagram illustrating a projection display system according to a sixth embodiment of the present application;

fig. 17 is a schematic structural diagram of a projection display system according to a seventh embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The degree of perception of human eyes caused by light with different wavelengths is different, and the brightness degree of human eyes is also different for monochromatic light with the same power but different wavelengths; through a large number of experimental measurements, under bright environment (the brightness is more than 3 cd/m)²) The sensitivity of the human eye to light reaches a maximum at a wavelength of 555nm, and decreases rapidly away from this wavelength; if P is in the unit wavelength_λThe radiant energy flux of the tiles is equivalent to phi_λLuminous flux of lumens, then the ratio K_λ＝Ф_λ/P_λCan represent the lumen number corresponding to the radiant energy flux of 1 watt; this value K corresponds to yellow light of 555nm wavelength₅₅₅And a maximum of about 683 lm/W. K for monochromatic light of any other wavelength_λAnd K₅₅₅The ratio characterizes the relative sensitivity of the human eye to this monochromatic light, called spectral luminous efficiency (spectral luminous efficiency) or visibility function (visibility function), available as V_λIs represented by, i.e. V_λ＝K_λ/K₅₅₅The spectral luminous efficiency curve under photopic vision adopted by the International Commission on illumination (CIE) is shown in fig. 1.

In contrast to a light source, the luminous efficacy of which is the ratio of luminous flux emitted by the light source to luminous power, in lm/W, also referred to as the radiant luminous efficiency of the light source, is as follows for a broad-spectrum light source:

wherein phi_e(λ) is the radiant energy flux of a light source of wavelength λ.

For two different spectral power distributions P₁(lambda) and P₂(λ) if they generate tristimulus values X, Y and Z respectively equal, i.e.:

the two light sources appear to be the same color,

and

is the tristimulus value of the CIE1931XYZ standard, as shown in fig. 2.

The heat load of a Digital Micromirror Device (DMD) is mainly caused by the heat loss of incident light on the DMD, fig. 3 is a schematic diagram of an illuminated area of incident light on the DMD, and an incident light spot can be divided into 3 areas: the light spot exceeds the part (window area) of the reflector array, the edge part (boundary area) of the reflector array and the effective area (array area) of the reflector array, and the area ratio and the absorptivity of the window area in the set area are respectively x₁And alpha₁(ii) a The area ratio and the absorptivity of the boundary area in the set area are respectively x₂And alpha₂(ii) a The area ratio and the absorptivity of the array area in the set area are respectively x₃And alpha₃(ii) a If the total luminous flux displayed on the screen is phi, the optical viewing efficiencyK, the efficiency of light incident on the DMD to reach the screen is η₁The thermal load on the DMD is then:

wherein Q is_electricalThe thermal power generated to drive the DMD circuit is usually much smaller than the thermal loss of the incident light on the DMD, so that it can be concluded that the improvement of the optical viewing performance can effectively reduce the thermal load of the DMD, i.e. the total luminous flux displayed on the screen can be effectively increased by improving the optical viewing performance when the thermal load that the DMD can bear is not changed.

It can be seen that, in a projection display system, the heat resistance of the spatial light modulator is one of the important factors limiting the display brightness, and the heat load of the spatial light modulator is proportional to the incident light power; when the spatial light modulator has limited thermal endurance, the light power incident on the spatial light modulator is also limited, and for a specific light power, the higher the light viewing efficiency, the higher the brightness of the display of the projection display system.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a projection display system 10 according to a first embodiment of the present disclosure, including: a light source assembly 11, a wavelength tuning assembly 12, and a modulating assembly 13.

The light source assembly 11 is used for emitting projection light and emitting the projection light to the wavelength adjusting assembly 12, and the light source assembly 11 can be a light source assembly or a tricolor light source assembly for exciting fluorescence by laser.

The wavelength adjusting component 12 is used for receiving the projection light and adjusting the spectrum of the projection light so as to improve the luminous efficacy of the projection light, and the color coordinate of the adjusted projection light meets the preset color coordinate condition; the wavelength adjusting component 12 may be a reflective device or a transmissive device with wavelength selectivity, including but not limited to a long-pass filter, a short-pass filter, a band-pass filter, a notch filter, a dichroic mirror, or a polarization dichroic mirror.

The modulation component 13 is disposed on an exit light path of the wavelength adjustment component 12, and is configured to perform image modulation on light exiting from the wavelength adjustment component 12 to obtain corresponding image light, so as to form a projection image; the modulation component 13 includes a spatial light modulator, and the spatial light modulator can modulate the modulated projection light output by the wavelength adjustment component 12 and emit the modulated light.

According to the above formula (2), when the thermal load that the spatial light modulator can bear is not changed, the improvement of the luminous efficiency of light incident to the spatial light modulator can effectively improve the total luminous flux displayed on the projection screen, that is, the improvement of the display brightness. From the formula (1), the luminous efficacy of the light source is related to the spectral range thereof. Therefore, the light visibility of the light source can be improved by adjusting the spectrum of the light source, and the display brightness can be improved when the thermal load of the spatial light modulator is not changed.

Furthermore, as can be seen from the principle of three-primary-color display, almost all colors can be formed by mixing RGB three primary colors according to a certain specific ratio, and RGB three-color light combinations are generally used in display systems to display various colors, so that various color standards are proposed in the display industry, including the rec.709 standard and the DCI/P3 standard, etc., taking the rec.709 standard as an example, a color gamut is a triangular region surrounded by three points of R (0.64, 0.33), G (0.30, 0.60), B (0.15, 0.06) as color coordinates in the CIE1931 standard, and color coordinates of a recommended white field are (0.3127, 0.3290), as shown in fig. 5; if three lights with color coordinates respectively corresponding to the three vertex positions are used as three primary colors of the display system, a recommended white field with coordinates (0.3127, 0.3290) is generated by combination, and the ratio of the luminance of the three primary colors of light is calculated to be R: 21.3%, G: 71.5%, B: 7.2 percent. The luminous efficacy of the common RGB three-color light is about R: 220lm/W, G: 520lm/W, B: 80lm/W, and the power ratio of the tricolor light when the recommended white field is generated by mixing is calculated to be R: 29.8%, G: 42.4%, B: 27.8%, it can be found that when white light is synthesized, the ratio of the brightness to the power of the green primary light is much higher than that of the other two primary lights. Furthermore, the spectrum of green light is typically capable of covering the 555nm corresponding to the maximum luminous efficacy.

Therefore, in one embodiment, the wavelength adjustment component 12 can be used to adjust the spectrum of the green primary light, thereby improving the luminous efficacy of the green primary light. Furthermore, according to the mixing principle of the three primary colors and the requirements of white balance, saturation and the like after light combination, the color coordinate range of the green primary colors can be limited after the spectrum is adjusted, and then the spectrum of the green primary colors can be adjusted to meet the better display effect. In this embodiment, the color coordinates of the spectrally-adjusted green primary light satisfy the following preset color coordinate conditions, that is, the shadow area in fig. 6, where the preset color coordinate conditions are:

wherein, (x, y) is the color coordinate of the green primary light.

The light source module 11, the wavelength adjusting module 12 and the modulation module 13 may be configured in different specific structures according to actual requirements. The light source assembly 11 may be a light source combination for exciting fluorescence by laser, as shown in fig. 7, the light source assembly 11 includes a laser light source 111a and a wavelength conversion device 112a, the laser light source 111a is used for emitting exciting light, which may be a blue laser; the wavelength conversion device 112a is positioned in an emergent light path of the laser light source and is used for generating corresponding stimulated light based on at least part of the exciting light; specifically, the wavelength conversion device 112a is provided with at least one wavelength conversion region provided with a wavelength conversion material, and the excitation light is incident on the wavelength conversion region to excite the wavelength conversion material, so as to generate the stimulated light of the corresponding color, in this example, the projection light emitted by the light source component 11 is composed of a part of the excitation light and the stimulated light.

Alternatively, a combination of light sources that emit three primary colors of light respectively may be used, and as shown in fig. 8, the light source assembly 11 includes a blue light-emitting element 111b, a red light-emitting element 112b, a green light-emitting element 113b, and a light-combining element 114 b; the blue light emitting element 111b, the red light emitting element 112b, and the green light emitting element 113b are used to emit blue primary light, red primary light, and green primary light, respectively; the light combining element 114b is disposed in the light emitting paths of the blue light emitting element 111b, the red light emitting element 112b, and the green light emitting element 113b, and is configured to combine the blue primary light, the red primary light, and the green primary light to generate projection light, where the projection light is composed of the blue primary light, the red primary light, and the green primary light, and the projection light emitted by the light combining element 114b is incident to the wavelength adjusting assembly 12; the modulation component 13 may be a single modulator component, that is, the modulation component 13 is a single optical modulator, as shown in fig. 7 and 8, or may also be a multi-modulator component shown in fig. 9, in this embodiment, the modulation component 13 includes a first optical modulator 131, a second optical modulator 132, and a third optical modulator 133, and the first optical modulator 131, the second optical modulator 132, and the third optical modulator 133 may modulate blue light, red light, and green light, respectively, so as to obtain corresponding blue image light, red image light, and green image light.

Referring to fig. 10, fig. 10 is a schematic structural diagram of a second embodiment of a projection display system provided in the present application, in which the projection display system is a single-modulator projection display system, and the light source module is a light source module for exciting fluorescence by laser.

Further, the light source assembly of the present embodiment includes a laser light source 211 and a wavelength conversion device 212. The laser light source 211 emits excitation light to the wavelength conversion device 212 to excite the wavelength conversion material in the wavelength conversion device 212, thereby emitting excited fluorescence of a corresponding color. Taking the excitation light as blue light as an example, the wavelength conversion device 212 may at least include a red light region 2121, a green light region 2122, and a blue light region 2123. In this embodiment, the wavelength adjustment component may be a filter ring 22 disposed in association with the wavelength conversion device 212, that is, the filter ring 22 is disposed on the periphery of the wavelength conversion device 212 and has a concentric ring structure, it is understood that each region of the filter ring 22 corresponding to the wavelength conversion device 212 is at least provided with a red filter region 221, a green filter region 222, and a blue filter region 223; the red light filter area 221 may be configured to filter stray light included in the incident red fluorescent light, the green light filter area 222 may be configured to adjust a spectrum of the green fluorescent light, and the blue light filter area 223 may be configured to intercept a wavelength of the excitation light to obtain a primary blue light with a set wavelength. The wavelength conversion device 212 is configured with a driving device, which drives the wavelength conversion device 212 to periodically rotate, so that the red light region 2121, the green light region 2122, and the blue light region 2123 are periodically exposed to the optical path of the excitation light, the projection light emitted by the light source assembly is provided by the blue laser light and the green fluorescence and the red fluorescence excited by the excitation light, the red primary light is the red fluorescence generated by the excitation light exciting the red wavelength conversion material, and the green primary light is the green fluorescence generated by the excitation light exciting the green wavelength conversion material.

Specifically, as shown in fig. 10, the excitation light emitted from the laser light source 211 is incident on the wavelength conversion device 212 through the dichroic filter 24 coated in one area, wherein a part of the area (e.g., the central area) of the dichroic filter 24 is coated with a blue-transmitting anti-yellow layer, and the other area is coated with a reflective layer, and when the excitation light is incident on the red wavelength conversion region 2121 through the central area of the dichroic filter 24, the red wavelength conversion material on the red wavelength conversion region 2121 can be excited to generate red fluorescence; when the excitation light is incident to the green light region 2122 through the central region of the dichroic sheet 24, the green wavelength conversion material on the green wavelength conversion region 2122 may be excited to generate green fluorescence; when excitation light is incident to the blue light region 2123 through the central region of the dichroic sheet 24, it is scattered and reflected at the blue light region 2123; the generated red fluorescence, green fluorescence, and reflected blue light are again incident on the dichroic filter 24, at which time the red fluorescence and green fluorescence can be reflected by the dichroic filter 24 to the reflective element 25, and the blue light is reflected to the reflective element 25 at the area where the dichroic filter 24 is coated with the reflective film layer, it being understood that the reflective element 25 is disposed to correspond to the filter ring 22 as the wavelength adjustment member. Further, the red fluorescent light, the green fluorescent light, and the blue light are reflected to the corresponding filter regions of the filter ring 22, pass through the filter ring 22, and enter the modulation component 23. The modulation component 23 of the present embodiment is a single modulator component, and may include a TIR (Total Internal Reflection) prism 231 and a spatial light modulator 232, and the spatial light modulator 232 may be a DMD (Digital Micromirror Device), a transmissive liquid crystal light modulator, or a reflective liquid crystal light modulator, etc.

Further, the projection light is emitted from the filter ring 22 and enters the TIR prism 231, and is reflected to the spatial light modulator 232 at the internal reflection surface of the TIR prism 231 for image modulation, so as to obtain corresponding image light, and the image light further passes through the imaging optical system 26 (such as a projection lens) after being emitted through the TIR prism 231, and then is displayed on the projection screen.

In this embodiment, the green fluorescence passes through the dichroic filter 24 and the reflective element 25 and then enters the green filter of the green filter area 222, the normalized spectral power of the green fluorescence emitted from the wavelength conversion device 212 can be as shown in fig. 11, the green fluorescence has a wider spectrum, and it can be known that the luminous efficacy of the green fluorescence is limited by the spectral range and is smaller, and the spectrum of the green fluorescence can cover the 555nm wavelength with higher luminous efficacy, and the spectrum of the green fluorescence can be adjusted by selecting an appropriate green filter, so that the proportion of the wavelength band with lower spectral luminous efficacy is reduced, and the luminous efficacy of the green primary light is improved, thereby improving the whole luminous efficacy of the light source assembly, and realizing the improvement of the display brightness without increasing the thermal load of the modulation assembly 23.

In this embodiment, after the adopted modulation component 23 is determined, the thermal load of the modulation component 23 may be determined based on the corresponding spatial light modulator 232, that is, when the adopted spatial light modulator 232 is determined, the thermal load may be determined according to the device parameters, so as to obtain the corresponding total luminous flux displayed on the projection screen according to the display effect to be realized, and obtain a preset luminous efficacy according to the above formula (2), further, it is known that the luminous efficacy is related to the spectrum according to the formula (1) and the spectrum of the projection light may be adjusted by the wavelength adjustment component, so that the luminous efficacy of the projection light reaches the preset luminous efficacy. It can be understood that when the wavelength adjusting component is arranged, the corresponding spectral range is difficult to directly calculate by the formula of the luminous efficacy, so that the test can be performed by selecting elements with different wavelength selection characteristics until the obtained luminous efficacy reaches the preset luminous efficacy. Further, according to the above analysis, the optical viewing performance at the wavelength of 555nm is the largest, so the wavelength selection characteristic of the wavelength adjustment element can be adjusted based on 555nm as a reference value, that is, the wavelength selection characteristic of the wavelength adjustment element is at least that the spectrum near 555nm can pass through.

In one embodiment, the laser light source 211 selects 455nm blue laser, the blue laser incident on the red region 2121 and the green region 2122 of the wavelength conversion device 212 is excited to generate corresponding red fluorescence and green fluorescence, and the scattered blue light incident on the blue region 2123 is used as blue-based light. At this time, the color coordinates of the white field are (0.313, 0.329), the luminous efficacy and the color coordinates of the blue-base light are 32.8lm/W and (0.151, 0.023), respectively, and the luminous efficacy and the color coordinates of the red-base light are 220.0lm/W and (0.64, 0.33), respectively. If the technical solution of this embodiment is not adopted, the luminous efficacy and the color coordinates of the green primary color light are 510.1lm/W and (0.243, 0.672) respectively; the luminous efficacy of the white light is 290.0 lm/W; further, in the present embodiment, the spectrum of the green primary light is adjusted by selecting a suitable green light filter, specifically, the green light filter is a band pass filter, and the spectrum of the green primary light can be adjusted by using a filter with a passband of 525nm to 570nm, the luminous efficacy and the color coordinates of the adjusted green primary light are 644.0lm/W and (0.286, 0.699) respectively, and the luminous efficacy of the white light is 321.9 lm/W; if the maximum thermal load Q that the spatial light modulator 232 can bear is 40W, the thermal load Q may be 0.87 Φ/K (the commonly used device may refer to the DMD performance parameter of the texas instrument, it can be understood that the spatial light modulator 232 may be selected according to actual requirements, and the device performance parameters provided by different manufacturers may be different, which further causes different thermal loads of the spatial light modulator 232, and this embodiment does not limit this specific data), according to the commonly used spatial light modulator parameters and the subsequent parameters of the imaging optical system 26, the maximum white light luminance that the projection display system can display is 14800 lm.

In order to more clearly show the technical effect of the embodiment, the parameters of the projection system in the prior art are described, when the same spatial light modulator 232 is used, the maximum thermal load is the same, and the maximum white light luminance that can be displayed by the projection display system is 13333 lm. Comparing the maximum white light brightness of the projection display system, the maximum white light brightness of the projection display system of the embodiment is improved by about 11.0%.

Further, please refer to fig. 12 and 13, in which fig. 12 is a schematic structural diagram of a third embodiment of a projection display system provided in the present application, and fig. 13 is a schematic structural diagram of a fourth embodiment of the projection display system provided in the present application; as shown in fig. 12 and 13, the light source assembly may adopt a combination of light sources emitting lights of three primary colors, and in one embodiment, may adopt light emitting devices emitting lights of red, green and blue primary colors, respectively, and the wavelength adjustment assembly may be disposed in the light path of the green primary light or in the light path after the light of the three primary colors is combined; the modulating component may be the modulating component shown in fig. 10. The light emitting device may be a light emitting diode or a light emitting diode array.

Specifically, as shown in fig. 12, three sets of light emitting devices are a blue light emitting diode 311, a red light emitting diode 312, and a green light emitting diode 313, respectively, and a light combining component 32 is disposed in the light paths of the three sets of light emitting devices to combine the three primary colors of light. The present embodiment adopts the dichroic filter 321 and the dichroic filter 322 as the light combining component 32, and the dichroic filter 321 is disposed on the light paths of the blue light emitting diode 311 and the green light emitting diode 313, and can transmit blue light to reflect green light; the dichroic plate 322 is located on the optical path of the dichroic plate 321 and the red led 312, and can reflect red light and transmit light of other wavelength bands, so that the dichroic plate 321 and the dichroic plate 322 can be used to combine three primary colors of light. In this embodiment, the wavelength adjustment component 33 is disposed between the dichroic sheet 321 and the green led 313 for performing spectrum adjustment on the green primary light, and the specific principle is the same as that of the embodiment shown in fig. 10, and is not described herein again.

In the embodiment, the luminous energy efficiency and the color coordinates of the red primary color light are 192lm/W and (0.696, 0.303) respectively; the luminous efficiency of the white light is 252 lm/W; the luminous energy efficiency and color coordinates of the blue-base light are 58lm/W and (0.133, 0.075), respectively. The wavelength adjusting component 33 can be a band-pass filter, the pass band of the band-pass filter is 525 nm-570 nm, the luminous efficiency and the color coordinate of the green primary color light after spectrum adjustment are 640lm/W and (0.269,0.715) respectively, and the average luminous efficiency obtained when the projection display system is used for displaying an REC.709 standard white field is 252 lm/W.

To more clearly show the technical effect of the present embodiment, the parameters of the projection system in the prior art are described, when the same spatial light modulator 34 is used, the maximum thermal load is the same, and the luminous efficacy and the color coordinates of the green primary light are 519lm/W and (0.189,0.718) respectively when the spectrum of the green primary light is not adjusted, and when the projection display system is used to display the rec.709 standard white field, the obtained average luminous efficacy is 241 lm/W. Therefore, the maximum display brightness of the white field of the projection display system is improved by about 4.6% compared with the maximum display brightness of the white field of the projection display system in the prior art.

In another embodiment, as shown in fig. 13, three sets of light emitting devices are a blue light emitting diode 311, a red light emitting diode 312 and a green light emitting diode 313, respectively, and a light combining component 32 is disposed in the light paths of the three sets of light emitting devices to combine the three primary lights. The present embodiment adopts the dichroic filter 321 and the dichroic filter 322 as the light combining component 32, and the dichroic filter 321 is disposed on the light paths of the blue light emitting diode 311 and the green light emitting diode 313, and can transmit blue light to reflect green light; the dichroic plate 322 is located on the optical path of the dichroic plate 321 and the red led 312, and can reflect red light and transmit light of other wavelength bands, so that the dichroic plate 321 and the dichroic plate 322 can be used to combine three primary colors of light. In this embodiment, the wavelength adjusting component 33 is disposed on the light emitting path of the dichroic filter 322, and is used for performing spectrum adjustment on the green primary light in the combined light, and the specific principle is the same as that in the embodiment shown in fig. 10, and is not described herein again.

Further, the wavelength adjusting component 33 includes a notch filter 331 and a notch filter 332, and stop bands of the notch filter 331 and the notch filter 332 are 480nm to 525nm and 570nm to 600nm, respectively; preferably, the stop bands of the notch filter 331 and the notch filter 332 are 490nm to 525nm and 570nm to 600nm, respectively.

It is understood that the stop band of the notch filter 331 may also be between 480nm and 490nm, depending on the requirements of the particular application.

This embodiment provides a projection display system, projection display system includes the light source subassembly, wavelength adjustment subassembly 33 and modulation subassembly, before the projection light of light source subassembly output reachs the modulation subassembly, utilize wavelength adjustment subassembly 33 to adjust the projection light of light source subassembly outgoing for the light efficiency of the projection light after adjusting compares and adjusts before light efficiency and promotes, the light efficiency of the synthetic light that generates improves, thereby can improve under the unchangeable condition of the heat load of modulation subassembly and show luminance.

Further, referring to fig. 14, fig. 14 is a schematic structural diagram of a fifth embodiment of a projection display system provided in the present application, where the projection display system of the embodiment is a multi-modulator projection display system.

In this embodiment, the modulation assembly includes a first spatial light modulator 411, a second spatial light modulator 412, a third spatial light modulator 413, a TIR prism 414, and a Philips prism set 415. In fig. 14, a light source assembly is omitted, and it is understood that the light source assembly may be the light source assembly in any one of the embodiments of fig. 10 to 13, which is not described again in this embodiment. The wavelength adjustment component 42 is a filter disposed between the light source component and the modulation component, and specifically, the wavelength adjustment component 42 includes a first filter 421 and a second filter 422 disposed in sequence along the light path.

Projection light emitted by the light source component enters the first optical filter 421 and the second optical filter 422 for spectrum adjustment, the projection light after spectrum adjustment enters the Philips prism group 415 after being totally reflected by the TIR prism 414, the projection light is split by the Philips prism group 415 and then enters the first spatial light modulator 411, the second spatial light modulator 412 and the third spatial light modulator 413 respectively, wherein the first spatial light modulator 411, the second spatial light modulator 412 and the third spatial light modulator 413 respectively modulate blue laser, red primary light and green primary light to obtain corresponding blue image light, red image light and green image light. Further, the blue image light, the red image light, and the green image light are combined by the Philips prism assembly 415, and then incident on the imaging optical system 43, and image display is performed on the projection screen.

In this embodiment, the light source assembly for exciting fluorescence by laser shown in fig. 10 is taken as an example, the light source assembly includes a 465nm blue laser and a wavelength conversion device, the emitted projection light is composed of 465nm blue laser and excited fluorescence excited by excitation light, and the embodiment takes yellow fluorescence as an example.

The projection light sequentially passes through the first filter 421 and the second filter 422 before entering the TIR prism 414, so that the first filter 421 and the second filter 422 perform spectrum adjustment on the projection light; the first filter 421 and the second filter 422 may be notch filters, the stop band of the first filter 421 is 480nm to 525nm, and the stop band of the second filter 422 is 570nm to 600 nm.

The projection light is divided into three RGB colors by the TIR prism 414 and the Philips prism 415, and the three RGB colors are irradiated on the three spatial light modulators, and then reflected by the corresponding spatial light modulators and projected on the projection screen by the subsequent imaging optical system 43. In this way, the components of the green spectrum in the light beam incident on the spatial light modulator are limited to the range of 520nm to 570nm, where the luminous efficiency is high, that is, the wavelength of the green primary light after adjustment is 520nm to 570nm, so that the luminous efficiency of displaying the white field is improved, the corresponding laser fluorescence spectrum is as shown in fig. 15, fig. 15(a) is the laser fluorescence spectrum before adjustment, and fig. 15(b) is the laser fluorescence spectrum after adjustment using two filters (including the first filter 421 and the second filter 422).

Further, if the color separation wavelength of the green light and the blue light of the RGB light-splitting film of the Philips prism assembly 415 is 480nm, and the color separation wavelength of the green light and the red light is 590nm, that is, the Philips prism assembly 415 can transmit/reflect light with a wavelength greater than 480nm, and reflect/transmit light with a wavelength less than 480nm, so as to separate the blue light from the green light; the RGB light-splitting film may also transmit/reflect light having a wavelength greater than 590nm and reflect/transmit light having a wavelength less than 590nm, thereby separating green light from red light.

In a specific embodiment, the stop band of the first filter 421 is 480nm to 520nm, and the stop band of the second filter 422 is 580nm to 590nm, when the projection display system of this embodiment is used to display the rec.709 standard white field, the color coordinates of the white field are (0.313, 0.329), which can be calculated according to the color mixing rule and the calculation formula of the luminous efficacy: when the wavelength adjusting element 42 is not used to adjust the spectrum of the projection light, the luminous efficacy and the color coordinates of the green primary light are 577.0lm/W and (0.327, 0.639) respectively, the luminous efficacy and the color coordinates of the blue primary light are 50.5lm/W and (0.136, 0.040) respectively, the luminous efficacy and the color coordinates of the red primary light are 269.4lm/W and (0.649, 0.350) respectively, and the luminous efficacy of the synthesized white field is 324.4 lm/W. After the spectrum adjustment is performed by using the scheme of the embodiment, the luminous efficacy and the color coordinates of the green primary light are 633.6lm/W and (0.323, 0.664) respectively, the luminous efficacy and the color coordinates of the red primary light and the blue primary light are unchanged, and the luminous efficacy of the white light is 331.7 lm/W. Namely, the luminous efficacy of the green primary light is improved by using the technical scheme of the embodiment.

Further, describing the thermal load under multiple modulators, the thermal load of 3 spatial light modulators can be obtained according to the parameters of the common spatial light modulator and the parameters of the subsequent imaging optical system 43, which is about:

theoretically, if the maximum value of the total thermal load borne by the 3 spatial light modulators in the projection display system under the heat dissipation condition is 120W, the maximum luminance that can be displayed before spectral adjustment is about 44745lm, and the maximum luminance that can be displayed after the scheme of the present embodiment is used is 45752 lm. But actually, the maximum brightness that can be displayed by the projection display system is determined by the thermal load borne by the hottest spatial light modulator, the thermal load borne by the spatial light modulator corresponding to the green light is usually the highest, and if the maximum thermal load borne by the monolithic spatial light modulator is 40W, the lumen occupancy of the green primary light is 73.1% when the rec.709 standard white field is displayed before the spectrum adjustment, so the maximum white field brightness that can be displayed by the projection display system is limited by the spatial light modulator modulating the green light and is about 36291 lm; after the scheme of this embodiment is used, because the luminous efficiency of the green primary light is improved, the luminance of the green primary light is improved under the condition of adopting the same spatial light modulator, and the lumen duty ratio of the green primary light when the same white field is displayed is reduced to 71.8%, the maximum brightness of the white field which can be displayed by the projection display system is about 40572lm, and the luminance is improved by about 11.8%.

It should be understood that the positions of the first filter 421 and the second filter 422 can be exchanged, the first filter 421 and the second filter 422 can also be replaced by wavelength selection devices such as dichroic mirrors with the same operating band, the stop band of the first filter 421 can also be 520nm to 525nm, and the stop band of the second filter 422 can also be 570nm to 580nm or 590nm to 600 nm.

Further, referring to fig. 16, fig. 16 is a schematic structural diagram of a sixth embodiment of the projection display system provided in the present application, where the projection display system of the embodiment is a multi-modulator projection display system, and in addition, the projection display system of the present embodiment further includes a light combining component disposed in an exit light path of the modulation component, and the light combining component is configured to combine three primary color image lights emitted by the modulation component.

In this embodiment, the modulation component includes a first spatial light modulator 511, a second spatial light modulator 512, and a third spatial light modulator 513, where the first spatial light modulator 511, the second spatial light modulator 512, and the third spatial light modulator 513 modulate the blue laser, the red primary light, and the green primary light respectively to obtain corresponding blue image light, red image light, and green image light. The light source module is omitted in fig. 16, and it is understood that the light source module may be the light source module in any one of the embodiments of fig. 10 to 13, which is not described in detail herein. The wavelength adjusting member 52 is a filter disposed between the light source assembly and the modulating member, and specifically, the wavelength adjusting member 52 is a band pass filter disposed between the light source assembly and the third spatial light modulator 513.

As shown in fig. 16, the projection light passes through the focusing lens 53 and then enters the first dichroic mirror 541, the first dichroic mirror 541 is configured to transmit red light and reflect light of other wavelength bands, so that the projection light is divided into red-based light and mixed light of blue-based light and green-based light after passing through the first dichroic mirror 541; the red-based light is further reflected by the mirror 551 and then enters the second spatial light modulator 512. The mixed light of the primary color blue light and the primary color green light further enters the second dichroic mirror 542, the second dichroic mirror 542 is configured to reflect the green light and transmit light in other wavelength bands, so that the primary color green light is reflected and enters the third spatial light modulator 513, and the primary color blue light is transmitted and then further reflected by the reflecting mirror 552 and the reflecting mirror 553 to the first spatial light modulator 511.

If the three spatial light modulators are liquid crystal spatial light modulators, the absorptances of the three liquid crystal spatial light modulators are respectively A, and the efficiency of projecting the light incident to the liquid crystal spatial light modulators on the projection screen is eta₂Then when the projection screen displays the brightness of phi, the thermal load Q of the liquid crystal spatial light modulator is (phi multiplied by A)/(K multiplied by eta)₂)。

The color separation wavelength of the first dichroic mirror 541 is 580nm, and the color separation wavelength of the second dichroic mirror 542 is 490 nm. The light source component comprises a 465nm blue laser and a wavelength conversion device, the emitted projection light is composed of 465nm blue laser and excited fluorescence excited by excitation light, and yellow fluorescence is taken as an example in the embodiment.

The passband of the wavelength adjusting component 52 is 520nm to 570nm, before the spectrum of the green primary color light is adjusted, the luminous efficiency of the green primary color light is 579.6lm/W, and the luminous efficiency of the displayed white field is 317.3 lm/W; after the spectrum of the green primary light is adjusted, the luminous efficiency and the color coordinate of the green primary light are 635.8lm/W and (0.286, 0.698) respectively, the luminous efficiency of the white light is 323.5lm/W, compared with the luminous efficiency and the color coordinate before adjustment, the luminous efficiency and the color coordinate of the green primary light are improved by about 7.1%, and when the total heat load of the liquid crystal spatial light modulator is not increased and the efficiency of the projection display system is not changed, the maximum brightness of the display REC.709 standard white field is also improved by about 7.1%.

Further, please refer to fig. 17, fig. 17 is a schematic structural diagram of a seventh embodiment of the projection display system provided in the present application, the projection display system of the embodiment is a multi-modulator projection display system, in addition, the projection display system of the embodiment further includes a light combining component disposed in an exit light path of the modulation component, and the light combining component is configured to combine three primary color image lights emitted by the modulation component.

In this embodiment, the modulation component includes a first spatial light modulator 611, a second spatial light modulator 612, and a third spatial light modulator 613, where the first spatial light modulator 611, the second spatial light modulator 612, and the third spatial light modulator 613 modulate the blue laser, the red primary light, and the green primary light respectively to obtain the corresponding blue image light, the red image light, and the green image light. Fig. 17 omits a light source assembly, and it can be understood that the structure of the light source assembly may be similar to that of the light source assembly in any one of the embodiments of fig. 10 to 13, except that the projection light emitted by the light source assembly in this embodiment is polarized projection light, which is not described again in this application. The wavelength adjusting member 62 is a filter disposed between the light source assembly and the modulating assembly, and specifically, the wavelength adjusting member 62 is a band pass filter disposed between the light source assembly and the third spatial light modulator 613.

As shown in fig. 17, the polarized projection light enters the first dichroic mirror 641 after passing through the focusing lens 63, and the first dichroic mirror 641 is configured to reflect the blue light and transmit the light of other wavelength bands, so that the polarized projection light is divided into the blue-based light and the mixed light of the red-based light and the green-based light after passing through the first dichroic mirror 641; the blue-base light is further reflected by the mirror 65 and then enters the first spatial light modulator 611. The mixed light of the red primary light and the green primary light further enters the second dichroic mirror 642, the second dichroic mirror 642 is used for reflecting the green light and transmitting the light of other wavelength bands, the green primary light is further reflected and then enters the third spatial light modulator 613, and the red primary light is reflected to the second spatial light modulator 612 after being transmitted.

In this embodiment, the dichroic wavelengths of the first dichroic mirror 641 and the second dichroic mirror 642 may be the same as the dichroic mirror in fig. 16, and the passband of the bandpass filter is the same as the bandpass filter in fig. 16, so the specific analysis of this embodiment is the same as the embodiment shown in fig. 16, and will not be described again here.

According to the light path in front of the spatial light modulator in the projection display system, the reflection or transmission devices with the wavelength selection characteristic are added, the reflection or transmission devices with the wavelength selection characteristic can modify the spectral characteristics of green primary light incident on the spatial light modulator, the energy proportion of a lower wave band of spectral luminous visual efficiency is reduced, and therefore the luminous visual efficiency of the green primary light incident on the spatial light modulator is improved to more than 590lm/W, the whole luminous visual efficiency is improved when a white field is displayed, and finally the display brightness is improved under the condition that the heat load of the spatial light modulator is not increased.

The above embodiments are merely examples, and not intended to limit the scope of the present application, and all modifications, equivalents, and equivalent structures that may be made by using the contents of the specification and drawings or applied directly or indirectly to other related technical fields are intended to be included within the scope of the present application.

Claims

1. A projection display system, comprising:

a light source assembly for emitting projection light;

the wavelength adjusting component is used for receiving the projection light and adjusting the spectrum of the projection light so as to improve the luminous efficacy of the projection light;

and the modulation component is arranged on the emergent light path of the wavelength adjusting component and is used for carrying out image modulation on the light emitted by the wavelength adjusting component to obtain corresponding image light so as to form a projected image.

2. The projection display system of claim 1,

the wavelength adjusting component is used for adjusting the spectrum of green primary light in the projection light so as to improve the luminous efficacy of the green primary light.

3. The projection display system of claim 2 wherein the color coordinates of the spectrally modified green primary light satisfy a preset color coordinate condition:

4. the projection display system of claim 2,

the luminous efficacy of the spectrum-adjusted green primary light is greater than 590 lm/W.

5. The projection display system of claim 1,

the light source assembly comprises a laser light source and a wavelength conversion device, and at least one wavelength conversion region is arranged on the wavelength conversion device;

the laser light source is used for emitting exciting light;

the wavelength conversion device is positioned in an emergent light path of the laser light source and used for generating corresponding stimulated light based on at least part of the exciting light;

wherein the projected light is composed of a portion of the excitation light and the stimulated light.

6. The projection display system of claim 1,

the light source component comprises a blue light emitting element, a red light emitting element, a green light emitting element and a light combining element;

the blue light emitting element, the red light emitting element and the green light emitting element are respectively used for emitting blue primary light, red primary light and green primary light;

the light combination element is arranged in an emergent light path of the blue light emitting element, the red light emitting element and the green light emitting element and is used for combining the blue primary light, the red primary light and the green primary light;

wherein the projection light is composed of the blue primary light, the red primary light, and the green primary light.

7. The projection display system of claim 1,

the wavelength adjusting assembly comprises a first optical filter and a second optical filter which are sequentially arranged between the light source assembly and the modulating assembly.

8. The projection display system of claim 7,

the stopband of the first optical filter is 480 nm-525 nm, and the stopband of the second optical filter is 570 nm-600 nm.

9. The projection display system of claim 1,

the wavelength adjusting component is a band-pass filter arranged on a light path of green primary light in the projection light.

10. The projection display system of claim 9,

the passband of the band-pass filter is 520 nm-570 nm.