A projection display system

Abstract

This application discloses a projection display system, which includes a light source component, a wavelength adjustment component, a modulation component, and a light combining component. The modulation component includes multiple light modulators. The light source component emits projection light containing three primary colors. The wavelength adjustment component receives the projection light and adjusts its spectrum to achieve thermal load balance among the multiple light modulators when the spectrally adjusted projection light is incident on them. The multiple light modulators are respectively positioned in the optical path of the three primary colors emitted by the wavelength adjustment component to perform image modulation on the three primary colors, obtaining corresponding three primary color image light. The light combining component receives the three primary color image light and combines it to form a color projection image. Through the above method, this application can achieve thermal load balance among the multiple light modulators and improve display brightness without increasing the maximum thermal load of the multiple light modulators.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically to a projection display system. Background Technology

[0002] The display brightness of a projection display system is limited by many factors, the most important of which are the brightness of the light source and the heat resistance of the spatial light modulator. With the continuous development of light source technology, especially the advancement of laser light source and laser phosphor light source technology, the heat resistance of the spatial light modulator has gradually become a bottleneck limiting display brightness. Existing projection display systems include projection display systems using RGB pure laser as the light source and projection display systems using laser and phosphor as the light source. In these two schemes, the light power illuminating the spatial light modulator is seriously unbalanced, that is, the heat load on the spatial light modulator is unbalanced, and the maximum white light brightness that can be displayed is not high. Summary of the Invention

[0003] This application provides a projection display system that can balance the thermal load of multiple light modulators, thereby improving display brightness without increasing the maximum thermal load of the multiple light modulators.

[0004] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows: A projection display system is provided, comprising: a light source component, a wavelength adjustment component, a modulation component, and a light combining component. The modulation component includes multiple light modulators. The light source component emits projection light containing three primary colors. The wavelength adjustment component receives the projection light and adjusts its spectrum so that when the spectrally adjusted projection light is incident on the multiple light modulators, the thermal load of the multiple light modulators reaches a thermal load balance condition. The multiple light modulators are respectively disposed in the optical path of the three primary colors emitted by the wavelength adjustment component, and are used to perform image modulation on the three primary colors to obtain corresponding three primary color image light. The light combining component receives the three primary color image light and combines the three primary color image light to form a color projection image.

[0005] The beneficial effects of this application through the above scheme are as follows: using the light generated by the light source component and the wavelength conversion device as the light source, filtering the laser emitted by the wavelength conversion device, and selecting light with a suitable spectral distribution, so that the power of the light illuminating multiple light modulators is as balanced as possible, the heat load on the light modulator with the largest heat load is reduced, thereby improving the display brightness without increasing the maximum heat load of a single light modulator, and balancing the temperature rise of multiple light modulators, so that the thermal effects such as thermal expansion on the light path are more balanced, and reducing the display quality reduction caused by the relative thermal displacement between light modulators. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0007] Figure 1 It is the spectral luminous efficiency curve under photopic vision;

[0008] Figure 2 It is the Rec.709 standard color gamut diagram;

[0009] Figure 3 This is a schematic diagram of the area illuminated by incident light on the DMD;

[0010] Figure 4 This is a schematic diagram of the structure of the first embodiment of the projection display system provided in this application;

[0011] Figure 5 This is a schematic diagram of the structure of the second embodiment of the projection display system provided in this application;

[0012] Figure 6 This is a schematic diagram of the structure of the third embodiment of the projection display system provided in this application;

[0013] Figure 7 yes Figure 6 A schematic diagram of the normalized power spectrum of the three primary colors in the embodiment shown;

[0014] Figure 8 This is a schematic diagram of the structure of the fourth embodiment of the projection display system provided in this application;

[0015] Figure 9 This is a schematic diagram of the structure of the fifth embodiment of the projection display system provided in this application;

[0016] Figure 10 This is a schematic diagram of the structure of the sixth embodiment of the projection display system provided in this application;

[0017] Figure 11 This is a schematic diagram of the structure of the seventh embodiment of the projection display system provided in this application;

[0018] Figure 12 This is a schematic diagram of the structure of the eighth embodiment of the projection display system provided in this application;

[0019] Figure 13 yes Figure 12 A schematic diagram of the normalized power spectrum of the three primary colors in the embodiment shown;

[0020] Figure 14This is a schematic diagram of the structure of the ninth embodiment of the projection display system provided in this application;

[0021] Figure 15 yes Figure 14 The illustrated embodiment shows a schematic diagram of the normalized power spectrum of the three primary colors. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] Different wavelengths of light elicit different levels of perception from the human eye. Even for monochromatic light of the same power but different wavelengths, the perceived brightness varies. Extensive experimental measurements have shown that in bright environments (brightness greater than 3 cd / m²), the perceived brightness of light varies. 2 The human eye's sensitivity to light reaches its maximum at a wavelength of 555 nm, and decreases rapidly at wavelengths far from this point; if P... λ The radiative energy flux of a watt is equivalent to Ф λ The luminous flux of lumens, then its ratio K λ =Ф λ / P λ This can represent the number of lumens corresponding to 1 watt of radiant energy flux; the value K corresponding to yellow light with a wavelength of 555nm. 555 Maximum, approximately 683 lm / W. KL of any other wavelength of monochromatic light... λ With K 555 The ratio of spectral efficiency to visual sensitivity of the human eye to that monochromatic light is called spectral luminous efficiency or visibility function, and can be expressed as V. λ It means, i.e., V λ =K λ / K 555 The spectral luminous efficacy curve under photopic vision, adopted by the International Commission on Illumination (CIE), is as follows: Figure 1 As shown.

[0024] In contrast, the luminous efficacy of a light source is the ratio of its luminous flux to its luminous power, measured in lm / W, and is also known as the radiative luminous efficiency of the light source. For broadband light sources, the luminous efficacy is as follows:

[0025]

[0026] Where, Φ e (λ) is the radiant flux of a light source with wavelength λ.

[0027] For color displays using three primary colors, almost all colors can be created by mixing the RGB primary colors in a specific ratio. Display systems typically use RGB combinations to display various colors. To this end, the display industry has developed several color standards, including Rec.709 and DCI / P3. Taking Rec.709 as an example, its defined color gamut is a triangular area enclosed by the three points with color coordinates R(0.64, 0.33), G(0.30, 0.60), and B(0.15, 0.06) in the CIE 1931 standard. The recommended white point color coordinates are (0.3127, 0.3290). Figure 2 As shown; if the three colors of light corresponding to the three vertex positions of the color coordinates are used as the three primary colors of the display system, the recommended white field with coordinates (0.3127, 0.3290) can be generated when the brightness ratios of the three primary color lights are R: 21.3%, G: 71.5%, and B: 7.2%, respectively, according to the color mixing law.

[0028] In projection equipment, the heat load of the digital micromirror device (DMD) mainly comes from the heat loss of incident light on the DMD. Figure 3 The diagram shows the area illuminated by incident light on the DMD. The incident light spot can be divided into three regions: the portion of the light spot extending beyond the mirror array (window region), the edge portion of the mirror array (boundary region), and the effective region of the mirror array (array region). The area ratio and absorptivity of the window region within the defined region are x1 and α1, respectively; the area ratio and absorptivity of the boundary region within the defined region are x2 and α2, respectively; and the area ratio and absorptivity of the array region within the defined region are x3 and α3, respectively. If the total luminous flux displayed on the screen is Ф, the optical efficiency is K, and the efficiency of the light incident on the DMD reaching the screen is η1, then the heat load on the DMD is:

[0029]

[0030] Among them, Q electrical The heat power generated to drive the DMD circuit is usually much smaller than the heat loss of the incident light on the DMD. Therefore, it can be concluded that improving the optical performance can effectively reduce the thermal load of the DMD. That is, when the thermal load that the DMD can withstand remains unchanged, improving the optical performance can effectively increase the total luminous flux displayed on the screen.

[0031] For a projection system with multiple digital micromirror devices (spatial light modulators), the maximum white field brightness that the system can display is determined by the photothermal load that the hottest spatial light modulator can withstand. Taking a projection system with three spatial light modulators as an example, if the light source can produce sufficiently high brightness, let the upper limit of the thermal load of a single spatial light modulator be Q. M The photothermal loads of the three spatial light modulators during white field display are Q0 and Q1 respectively. R Q G And Q B The maximum white field brightness that the system can display is determined by the photothermal load Q that the hottest spatial light modulator can withstand. i Decision, i.e., Q i ≤Q M -Q electrical .

[0032] If the powers of the three primary colors of light illuminating the spatial light modulator are P R 、P G and P B The dimensionless coefficient of variation can be used to characterize the power dispersion of the three primary colors of light. It is defined as the ratio of the standard deviation to the mean of the data set, i.e.:

[0033]

[0034] in, This is the average value.

[0035] Similarly, the power dispersion of any two colors of light can be defined as:

[0036]

[0037] Where i, j = R, G, B, and i ≠ j.

[0038] The power dispersion of different colors of light can characterize the balance of power distribution when the three primary colors of light are incident on the corresponding spatial light modulators; the smaller the power dispersion, the more balanced the power distribution when the three primary colors of light are incident on the corresponding spatial light modulators.

[0039] The CIE LUV color space and the CIE 1931 XYZ color space are uniform color spaces based on different standards. The color space coordinates of these two color spaces can be used to represent and evaluate colors. The conversion relationship between CIE LUV color space coordinates and CIE 1931 XYZ color space coordinates is as follows:

[0040]

[0041] Where (x,y) are the coordinates in the CIE1931 XYZ color space, and (u',v') are the coordinates in the CIE LUV color space.

[0042] The color gamut coverage of a projection system characterizes the display device's ability to reproduce colors. If the color coordinates of the test center point of a projector displaying a pure RGB field in the CIE 1976 standard are (u'... r ,v' r ), (u' g ,v' g ) and (u' b ,v' b If ), then the color gamut area is defined as:

[0043]

[0044] The color gamut coverage is defined as:

[0045]

[0046] The SJ / T 11346-2015 standard requires a color gamut coverage of ≥32% for projectors, while the GB 32028-2015 standard requires a color gamut coverage of ≥33% for high color gamut projectors.

[0047] Currently, projection display systems with three spatial light modulators mainly utilize the three-primary-color display principle. Three spatial light modulators are used to modulate the RGB three primary colors of light respectively, and then a light combining element is used to combine the modulated three primary color patterns into a complete color pattern. Different projection display systems use different spectral characteristics of the three primary colors of light, so the color coordinates and light performance of the corresponding three primary colors of light are also different. According to the color mixing principle, when displaying a white field, the brightness and power ratio of the three primary colors of light illuminating the three spatial light modulators are different and vary greatly.

[0048] Assuming that the photothermal load on the spatial light modulator is proportional to the light power illuminating it, and that the power of the three primary colors is relatively balanced, that is, the thermal load of the three spatial light modulators is relatively balanced.

[0049] See Figure 4 , Figure 4 This is a schematic diagram of the structure of the first embodiment of the projection display system provided in this application. The projection display system includes: a light source component 11, a wavelength adjustment component 12, a modulation component 13, and a light combining component 14; in this embodiment, the modulation component 13 includes three light modulators: a first light modulator 131, a second light modulator 132, and a third light modulator 133.

[0050] The light source assembly 11 is used to emit projection light and to emit the projection light to the wavelength adjustment assembly 12. The light source assembly 11 can be a laser-excited fluorescence light source assembly or a three-primary-color light source assembly; wherein, the projection light includes red primary color light, blue primary color light and green primary color light.

[0051] The wavelength adjustment component 12 is used to receive the projection light and adjust the spectrum of the projection light to improve the optical performance of the projection light incident on the modulation component 13, and the power distribution of the adjusted projection light incident on the modulation component 13 is uniform. The wavelength adjustment component 12 can be a wavelength-selective reflective or transmissive device, including but not limited to long-pass filters, short-pass filters, band-pass filters, notch filters, dichroic mirrors, or polarizing dichroic mirrors. In addition, the wavelength adjustment component 12 may also include a supplementary light source, and the spectrum of the corresponding color light emitted by the light source component 11 is adjusted by selecting the wavelength of the supplementary light source.

[0052] The modulation component 13 is disposed on the output light path of the wavelength adjustment component 12. In this embodiment, the modulation component 13 includes three optical modulators, which are respectively disposed on the output light paths of red primary color light, blue primary color light and green primary color light. They are used to perform image modulation on the red primary color light, blue primary color light and green primary color light respectively to obtain corresponding red image light, blue image light and green image light.

[0053] The light combining component 14 is disposed on the output light path of the modulation component 13. It is used to receive the red image light, blue image light and green image light obtained after modulation by the modulation component 13. The red image light, blue image light and green image light are combined to obtain a color projection image. Furthermore, the color projection image can be projected onto the projection plane through a projection lens (not shown in the figure) disposed on the output light path of the light combining component 14.

[0054] According to the above formula (2), when the thermal load that the spatial light modulator can withstand remains unchanged, improving the light performance incident on the spatial light modulator can effectively increase the total luminous flux displayed on the screen, that is, increase the display brightness. For a projection system with three spatial light modulators, the maximum white field brightness that can be displayed is determined by the photothermal load that the hottest spatial light modulator can withstand. According to formula (1), the light performance of the light source is related to its spectral range. Therefore, by adjusting the spectrum of the projection light emitted from the light source assembly, the light performance of the light incident on each spatial light modulator can be adjusted, so that the thermal load of each spatial light modulator reaches the thermal load balance condition, and the thermal load of each spatial light modulator reaches various thermal load limits, thereby providing the brightness of the projection display system without increasing the maximum thermal load of a single spatial light modulator.

[0055] Furthermore, the thermal load balance of each spatial light modulator can be characterized by the power balance of the light incident on each spatial light modulator, and the power balance of the light incident on each spatial light modulator can be characterized by the power dispersion coefficient of the light incident on each spatial light modulator. Thus, the thermal load balance condition between each spatial light modulator can be achieved when the power dispersion coefficient of the light incident on each spatial light modulator is less than or equal to a preset power dispersion coefficient.

[0056] Furthermore, in this embodiment, the modulation component 13 includes three spatial light modulators. Therefore, the preset power dispersion coefficient may include a first preset power dispersion coefficient and a second preset power dispersion coefficient. Further, the condition for achieving thermal load balance among the thermal loads of each spatial light modulator can be that the power dispersion coefficient of the light incident on the three spatial light modulators is less than or equal to the first preset power dispersion coefficient, and that the power dispersion coefficient between the two light sources with higher power incident on the three spatial light modulators is less than or equal to the second preset power dispersion coefficient. In this embodiment, the first preset power dispersion coefficient may be 25%, and the second preset power dispersion coefficient may be 18%. It is understood that the specific values ​​of the first and second preset power dispersion coefficients can be modulated according to actual needs, and this embodiment does not impose specific limitations on this.

[0057] Furthermore, based on the color reproduction requirements of the projection display system, in this embodiment, after adjusting the spectrum of the projection light emitted from the light source component, the color gamut coverage of the projection display system is greater than or equal to the preset color gamut coverage. In this embodiment, the preset color gamut coverage is set according to GB32028-2015 standard and / or GB 32028-2015; specifically, the preset color gamut coverage can be 32% or 33%.

[0058] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of the second embodiment of the projection display system provided in this application. In this embodiment, the projection display system includes: a light source component 11, a wavelength adjustment component 12, a modulation component 13, and a light combining component 14; wherein, the modulation component includes three light modulators; the light source component 11 includes a first light source 111, a wavelength conversion device 112, and a second light source 113.

[0059] The first light source 111 is used to provide excitation light, which can be excitation light; the wavelength conversion device 112 is disposed in the optical path of the excitation light, which is used to receive the excitation light and generate corresponding laser light, and emit the generated laser light to the wavelength adjustment component 12; specifically, the laser light includes at least two of the three primary colors, and the wavelength conversion device 112 is provided with at least one wavelength conversion region.

[0060] The second light source 113 is used to emit primary color light of a preset wavelength band, and the primary color light of the preset wavelength band is different in color from the primary color light contained in the laser. Specifically, the second light source 113 can generate at least one laser, which can be a laser or a light-emitting diode, and can send the generated laser to the wavelength adjustment component 12 through the laser emission optical path. Taking a laser as an example, the laser emitted by the second light source 113 can include lasers of multiple colors, such as blue laser, red light or green light.

[0061] In a specific embodiment, the first light source 111 may be a blue light source. The blue laser emitted from the blue light source is incident on the wavelength conversion region of the wavelength conversion device 112 as excitation light. The wavelength conversion region contains a wavelength conversion material capable of wavelength conversion. The wavelength conversion material receives the blue laser and emits a laser with a wavelength different from the blue laser to the wavelength adjustment component 12. The wavelength conversion material may be a quantum dot or a fluorescent material, etc. Taking a fluorescent material as an example, fluorescent materials of different colors can emit fluorescence of the corresponding color under the excitation of excitation light. The fluorescent material may include yellow fluorescent material, red fluorescent material, or green fluorescent material, etc.

[0062] The wavelength adjustment component 12 is disposed in the optical path of the laser beam and is used to filter the laser beam to obtain filtered light with a preset wavelength band. Specifically, the wavelength adjustment component 13 includes at least one wavelength selection element, which can filter the incident laser beam and output corresponding filtered light with a wavelength of the preset wavelength band. For example, if the laser beam is yellow fluorescence, the wavelength selection element filters the yellow fluorescence to generate red fluorescence and / or green fluorescence.

[0063] The modulation component 13 is disposed on the output optical path of the wavelength adjustment component 12. In this embodiment, the modulation component 13 includes three optical modulators, which are respectively disposed on the output optical paths of red primary color light, blue primary color light and green primary color light. They are used to perform image modulation on the red primary color light, blue primary color light and green primary color light respectively to obtain corresponding red image light, blue image light and green image light; the thermal load of the three optical modulators meets the thermal load balance condition.

[0064] The light combining component 14 is disposed in the optical path of the image light (including red image light, blue image light and green image light), and is used to perform light combining processing on multiple image lights to output composite light to form a color projection image; specifically, the light combining component 14 can combine the image lights emitted from multiple light modulators to generate composite light, which is white light.

[0065] Further, please refer to Figure 6 , Figure 6This is a schematic diagram of the structure of the third embodiment of the projection display system provided in this application. In one embodiment, the first light source 111 is an excitation light source, and the emission wavelength of the excitation light source can be 455nm. The excitation light source can be a blue light source, that is, the excitation light is 455nm blue light. The excitation light is incident on the wavelength conversion device 112, and the wavelength conversion device 112 absorbs the excitation light and emits a corresponding laser. In this embodiment, the wavelength conversion device 112 includes a yellow light conversion region and a green light conversion region, and the corresponding laser includes yellow fluorescence and green fluorescence. The second light source 113 is a blue light source, which is used to generate blue primary color light, and the wavelength of the blue primary color light can be 465nm.

[0066] Furthermore, such as Figure 6 As shown, the wavelength adjustment component includes a first wavelength selection element 121 having a first cutoff wavelength and a second wavelength selection element 122 having a second cutoff wavelength; the first wavelength selection element 121 is used to obtain red primary color light corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device 112; the second wavelength selection element 122 is used to obtain green primary color light corresponding to the second cutoff wavelength from the green fluorescence emitted by the wavelength conversion device 112.

[0067] There are three optical modulators: the first optical modulator 131 is set in the optical path of the filtered light (i.e., red primary color light) output by the first wavelength selection element 121, the second optical modulator 132 is set in the optical path of the filtered light (i.e., green primary color light) output by the second wavelength selection element 122, and the third optical modulator 133 is set in the optical path of the blue primary color light.

[0068] In this embodiment, the first wavelength selection element 121 is a filter with a cutoff wavelength of 590nm, and the second wavelength selection element 122 is a filter that cuts off the wavelength range of 520nm to 575nm. Thus, the first wavelength selection element 121 can select red fluorescence with a wavelength greater than 590nm from yellow fluorescence and use the red fluorescence as the red primary color light. The second wavelength selection element 122 can select green fluorescence with a wavelength range of 520nm to 575nm from yellow fluorescence and use the green fluorescence as the green primary color light.

[0069] The normalized power spectrum of this embodiment is as follows: Figure 7As shown, the color coordinates and luminous efficacy of blue primary light are (0.136, 0.040) and 50.5 lm / W, respectively; the color coordinates and luminous efficacy of red primary light are (0.649, 0.350) and 269.4 lm / W, respectively; and the color coordinates and luminous efficacy of green primary light are (0.287, 0.695) and 629.2 lm / W, respectively. The color coordinates of the synthesized white light are (0.313, 0.329). The luminous flux proportions of red, green, and blue primary colors are 26.60%, 68.21%, and 5.19%, respectively, with corresponding power proportions of 31.86%, 34.98%, and 33.16%. The power dispersion coefficients of red, green, and blue primary colors are 4.7%, which is less than the first preset power dispersion coefficient. The power dispersion coefficient of the two primary colors with higher power (red and green primary colors) is 3.8%, which is less than the second preset power dispersion coefficient. Therefore, in this embodiment, the power of the three primary colors incident on the corresponding light modulators is relatively balanced, and the photothermal load of the corresponding light modulators 131-133 is also relatively balanced. The color gamut coverage of the projection display system is 39.3%, which meets the GB32028-2015 standard, and the maximum white light brightness that can be displayed is 922.4×Q / η2, which is a significant improvement compared to the prior art.

[0070] This embodiment uses the first wavelength selection element 121 and the second wavelength selection element 122 to filter the three primary color lights, adjust the spectral distribution of the three primary color lights, and thus adjust the color coordinates of the three primary color lights. This ensures that the color gamut coverage of the projection display system meets the preset coverage while the light power distribution of the three primary color lights meets the thermal load balance condition. This makes the thermal load on the first light modulator 131, the second light modulator 132, and the third light modulator 133 as balanced as possible. Since the thermal load is related to the display brightness, the display brightness of the projection display system is improved while meeting the color gamut requirements.

[0071] In another implementation, please refer to Figure 8 , Figure 8 This is a schematic diagram of the fourth embodiment of the projection display system provided in this application. The projection display system is a projection display system with three light modulators that uses laser-excited fluorescence as a light source.

[0072] In this embodiment, the modulation components include a first optical modulator 211, a second optical modulator 212, and a third optical modulator 213, and the light combining components include a TIR (Total Internal Reflection) prism 221 and a Philips prism group 222. Figure 8 The light source component is omitted from the text; however, it can be understood that the structure of the light source component can be the same as described above. Figures 4 to 6The light source components in any of the embodiments have similar structures, and will not be described again in this embodiment.

[0073] The wavelength adjustment component 23 is a wavelength selection element disposed between the light source component and the modulation component. Specifically, the wavelength adjustment component 23 includes a first wavelength selection element 231 and a second wavelength selection element 232 disposed sequentially along the optical path.

[0074] The projection light emitted from the light source assembly is incident on the first wavelength selection element 231 and the second wavelength selection element 232 for spectral adjustment. After spectral adjustment, the projection light undergoes total internal reflection through the TIR prism 221 and enters the Philips prism group 222. The Philips prism group 222 splits the projection light and then incident it on the first light modulator 211, the second light modulator 212, and the third light modulator 213, respectively. The first light modulator 211, the second light modulator 212, and the third light modulator 213 modulate the red primary color light, the green primary color light, and the blue primary color light, respectively, to obtain the corresponding red image light, green image light, and blue image light. Further, the blue image light, red image light, and green image light are combined by the Philips prism group 222 and then incident on the imaging optical system 24 to display the image on the projection screen.

[0075] In yet another implementation, please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of the fifth embodiment of the projection display system provided in this application. The projection display system of this embodiment is a multi-modulator projection display system.

[0076] In this embodiment, the modulation component includes a first optical modulator 311, a second optical modulator 312, and a third optical modulator 313. The first optical modulator 311, the second optical modulator 312, and the third optical modulator 313 modulate the blue primary color light, the red primary color light, and the green primary color light respectively to obtain the corresponding blue image light, red image light, and green image light. Figure 9 The light source component is omitted from the text; however, it can be understood that the structure of the light source component can be the same as described above. Figures 4 to 6 The light source components in any of the embodiments are similar in structure, and will not be described again in this application.

[0077] like Figure 9As shown, the projected light passes through the focusing lens 33 and then enters the first dichroic mirror 341. The first dichroic mirror 341 transmits red light and reflects light of other wavelengths, thus splitting the projected light into red primary color light and a mixture of blue and green primary color light after passing through the first dichroic mirror 341. The red primary color light is further reflected by the reflecting mirror 351 and then enters the second light modulator 312. The mixture of blue and green primary color light further enters the second dichroic mirror 342, which reflects green light and transmits light of other wavelengths, thus causing the green primary color light to be reflected and then enter the third light modulator 313. The blue primary color light is transmitted and then further reflected by the reflecting mirrors 352 and 353 back to the first light modulator 311.

[0078] The wavelength adjustment component includes a first wavelength selection element 321 and a second wavelength selection element 322. The first wavelength selection element 321 is disposed between the second dichroic mirror 342 and the third optical modulator 313, and the second wavelength selection element 322 is disposed between the reflector 351 and the second optical modulator 312.

[0079] This embodiment provides a display scheme using modulation components. For a projection display system with multiple light modulators, the maximum brightness that the projection display system can display is limited by the light modulator with the largest heat load. This embodiment adjusts the spectral characteristics of the light beam illuminating each light modulator. While ensuring that the color gamut coverage of the projection display system meets the preset coverage, it distributes the heat load as evenly as possible among the multiple light modulators. This reduces the heat load borne by the light modulator with the largest heat load, thereby increasing the display brightness without increasing the maximum heat load of a single light modulator. Moreover, it can balance the temperature rise of multiple light modulators, making the thermal effects such as thermal expansion on the optical path more uniform. This reduces the display quality degradation caused by the relative thermal displacement between light modulators, such as thermal defocusing, thermal drift, and color separation.

[0080] For further information, please refer to [link / reference]. Figure 10 , Figure 10 This is a schematic diagram of the structure of the sixth embodiment of the projection display system provided in this application. The projection display system of this embodiment is a multi-modulator projection display system.

[0081] In this embodiment, the modulation component includes a first optical modulator 411, a second optical modulator 412, and a third optical modulator 413. The first optical modulator 411, the second optical modulator 412, and the third optical modulator 413 modulate the blue primary color light, the red primary color light, and the green primary color light respectively to obtain the corresponding blue image light, red image light, and green image light. Figure 10 The light source component is omitted from the text; however, it can be understood that the structure of the light source component can be the same as described above. Figure 4-Figure 6The light source components in any of the embodiments are similar in structure, the difference being that the projection light emitted by the light source component in this embodiment is polarized projection light, which will not be described in detail here.

[0082] The wavelength adjustment component includes a first wavelength selection element 421 and a second wavelength selection element 422. The first wavelength selection element 421 is a filter disposed between the light source component and the third light modulator 413; the second wavelength selection element 422 is a filter disposed between the light source component and the second light modulator 412.

[0083] like Figure 10 As shown, the polarized projection light is incident on the first dichroic mirror 441 after passing through the focusing lens 43. The first dichroic mirror 441 is used to reflect blue light and transmit light of other wavelengths, so that the polarized projection light is split into blue primary color light and a mixture of red primary color light and green primary color light after passing through the first dichroic mirror 441. The blue primary color light is further reflected by the reflecting mirror 45 and then incident on the first light modulator 411. The mixture of red primary color light and green primary color light is further incident on the second dichroic mirror 442. The second dichroic mirror 442 is used to reflect green light and transmit light of other wavelengths, so that the green primary color light is reflected and then incident on the third light modulator 413, and the red primary color light is transmitted and then incident on the second light modulator 412.

[0084] Please see Figure 11 , Figure 11 This is a schematic diagram of the seventh embodiment of the projection display system provided in this application. This embodiment is... Figure 5 Based on the illustrated embodiment, the wavelength adjustment component 52 in this embodiment includes a wavelength selection element 521 and a supplementary light source 522.

[0085] The first light source 111 is an excitation source with an emission wavelength of 455nm. The excitation source can be a blue light source, meaning the excitation light is blue light with a wavelength of 455nm. The excitation light is incident on a wavelength conversion device 512, which absorbs the excitation light and emits a corresponding laser beam. In this embodiment, the wavelength conversion device 512 includes a yellow light conversion region, and the corresponding laser beam includes yellow fluorescence. The second light source is a blue light source 513, which generates blue primary color light with a wavelength of 465nm.

[0086] In one specific embodiment, such as Figure 12As shown, the wavelength selection element 521 includes a first wavelength selection element 521a having a first cutoff wavelength and a second wavelength selection element 521b having a second cutoff wavelength; the first wavelength selection element 521a is used to obtain red fluorescence corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device 512; the second wavelength selection element 521b is used to obtain green primary color light corresponding to the second cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device 512.

[0087] The supplementary light source includes a first supplementary light source 522a, which emits red light. The first laser and the second laser emitted by the wavelength conversion device 512 are green primary color light and red fluorescence, respectively. The red fluorescence and the red light emitted by the first supplementary light source 522a are combined to obtain red primary color light.

[0088] There are three optical modulators: the first optical modulator 531 is set in the optical path of the filtered light output by the first wavelength selection element 521a, the second optical modulator 532 is set in the optical path of the filtered light output by the second wavelength selection element 521b, and the third optical modulator 533 is set in the optical path of the blue primary color light.

[0089] In this embodiment, the wavelength of the red light is 638nm; the first wavelength selection element 521a is a filter that cuts out wavelengths greater than 588nm; specifically, the first wavelength selection element 521a is used to cut out the portion of the yellow fluorescence with wavelengths greater than 588nm as red fluorescence, and the red fluorescence and the red light with a wavelength of 638nm together form the red primary color light, and the ratio of the luminous flux of the red light to the red fluorescence is 4:1.

[0090] The second wavelength selection element 521b is a filter that cuts out wavelengths greater than 520nm and less than 573nm. That is, the second wavelength selection element 521b is used to cut out the portion of yellow fluorescence with wavelengths from 520nm to 573nm as green primary color light.

[0091] The normalized power spectrum of the three primary colors is as follows: Figure 13As shown, the color coordinates and luminous efficacy of red primary color light are (0.662, 0.338) and 228.3 lm / W, respectively, while the color coordinates and luminous efficacy of green primary color light are (0.297, 0.687) and 636.0 lm / W, respectively. The color coordinates of the synthesized white light are (0.32, 0.34). The luminous flux proportions of red, green, and blue primary colors are 24.08%, 71.16%, and 4.76%, respectively, with corresponding power proportions of 33.85%, 35.90%, and 30.25%. The power dispersion coefficients of red, green, and blue primary colors are 8.6%, while the power dispersion coefficients of the two primary colors with higher power (red and green) are 4.2%, which are less than the aforementioned second preset power dispersion coefficient. Therefore, in this embodiment, the power of the three primary colors incident on the corresponding light modulators is relatively balanced, and the photothermal load of the corresponding light modulators 531-533 is relatively balanced. The color gamut coverage of the projection display system is 41.3%, which meets the GB 32028-2015 standard, and the maximum white light brightness that can be displayed is 893.8×Q / η2, which is a significant improvement compared to the prior art.

[0092] In another specific embodiment, such as Figure 14 As shown, the wavelength adjustment component 52 includes a first wavelength selection element 521a having a first cutoff wavelength, a second wavelength selection element 521b having a second cutoff wavelength, and a supplementary light source, which includes a first supplementary light source 522a and a second supplementary light source 522b.

[0093] Furthermore, the laser emitted by the wavelength conversion device 512 includes green fluorescence and red fluorescence. The first wavelength selection element 521a is used to obtain red fluorescence corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device 512. The first supplementary light source 522a is used to emit red light, that is, the first supplementary light source 522a is a red laser. The combination of red fluorescence and red light obtains red primary color light. The second wavelength selection element 521b is used to obtain green fluorescence corresponding to the second cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device 512. The second supplementary light source 522b is used to emit green light, that is, the second supplementary light source 522b is a green laser. The combination of green fluorescence and green light obtains green primary color light.

[0094] In this embodiment, the wavelength of the red light is 638nm, and the first wavelength selection element 521a is a filter that cuts out wavelengths greater than 580nm. Specifically, the first wavelength selection element 521a is used to cut out the portion of the yellow fluorescence with wavelengths greater than 580nm as red fluorescence. The red fluorescence and the red light with a wavelength of 638nm together form the red primary color light, and the ratio of the luminous flux of the red light to the red fluorescence is 17:3.

[0095] The wavelength of green light is 525nm. The second wavelength selection element 521b is a filter that cuts off the wavelength range greater than 520nm and less than 580nm. Specifically, the second wavelength selection element 521b is used to cut off the portion of yellow fluorescence with wavelengths from 520nm to 580nm as green fluorescence. The green fluorescence and the green light with a wavelength of 525nm together form the green primary color light, and the ratio of the luminous flux of green light to green fluorescence is 9:1.

[0096] The normalized power spectrum of this embodiment is as follows: Figure 15 As shown, the color coordinates and luminous efficacy of red primary color light are (0.638, 0.361) and 266.5 lm / W, respectively, while the color coordinates and luminous efficacy of green primary color light are (0.282, 0.685) and 585.4 lm / W, respectively. The color coordinates of the synthesized white light are (0.313, 0.329). The luminous flux proportions of red, green, and blue primary colors are 28.59%, 66.30%, and 5.11%, respectively, with corresponding power proportions of 33.35%, 35.20%, and 31.45%. The power dispersion coefficients of red, green, and blue primary colors are 5.6%, while the power dispersion coefficients of the two primary colors with higher power (red and green) are 3.8%, which are less than the first preset power dispersion coefficient. The color gamut coverage of the projection display system is 37.0%, which is less than the second preset power dispersion coefficient. Therefore, in this embodiment, the power of the three primary colors incident on the corresponding light modulators is relatively balanced, and the photothermal load of the corresponding light modulators 531-533 is relatively balanced. The maximum white light brightness that can be displayed is 883.0×Q / η2, which is a significant improvement compared to the prior art.

[0097] In other embodiments, the thermal load of the three light modulators can be increased to a certain limit to improve the maximum brightness that the projection display system can display. This application addresses a projection display system using three light modulators. When displaying the white field, the thermal load can be evenly distributed across the three light modulators, and the thermal load of each light modulator can be maximized to its thermal load limit. This reduces the thermal load of the light modulator with the highest thermal load in traditional solutions, and also evenly increases the thermal load of the three light modulators, fully utilizing their heat dissipation capabilities. This improves display brightness without increasing the maximum thermal load of any single light modulator. Furthermore, because the photothermal load on the three light modulators is relatively balanced, the temperature rise of the three light modulators can be balanced, resulting in a more even distribution of thermal effects such as thermal expansion on the optical path, reducing the display quality degradation caused by relative thermal displacement between the light modulators.

[0098] The above are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A projection display system, characterized in that, It includes a light source component, a wavelength adjustment component, a modulation component, and a light combining component, wherein the modulation component includes multiple optical modulators; wherein, The light source assembly is used to emit projection light containing three primary colors; The wavelength adjustment component is used to receive the projection light and adjust the spectrum of the projection light so that when the spectrum-adjusted projection light is incident on the plurality of optical modulators, the thermal load among the plurality of optical modulators reaches a thermal load balance condition. The plurality of optical modulators are respectively disposed in the optical path of the three primary color light emitted from the wavelength adjustment component, and are used to perform image modulation on the three primary color light to obtain the corresponding three primary color image light; The light combining component is used to receive the three primary color image light and combine the three primary color image light to form a color projection image; The thermal load equalization condition includes that the power dispersion coefficient of the light incident on the plurality of optical modulators is less than or equal to a preset power dispersion coefficient. Among them, the powers of the three primary colors of light illuminating the spatial light modulator are P R 、P G and P B The dimensionless coefficient of variation is used to characterize the power dispersion of the three primary colors, and is defined as the ratio of the standard deviation to the mean of this set of data, i.e.: in, This is the average value; The power dispersion of any two colors of light can be defined as: Where i, j = R, G, B, and i ≠ j.

2. The projection display system according to claim 1, characterized in that, The preset power dispersion coefficient includes a first preset power dispersion coefficient and a second preset power dispersion coefficient; The power dispersion coefficient of the light incident on the plurality of optical modulators is less than or equal to a preset power dispersion coefficient, including: The power dispersion coefficient of the light incident on the plurality of optical modulators is less than or equal to the first preset power dispersion coefficient, and among the light incident on the plurality of optical modulators, the power dispersion coefficient between the two light sources with higher power is less than or equal to the second preset power dispersion coefficient.

3. The projection display system according to claim 2, characterized in that, The first preset power dispersion factor is 25%, and the second preset power dispersion factor is 18%.

4. The projection display system according to claim 1, characterized in that, The light source assembly includes a first light source, a second light source, and a wavelength conversion device, wherein the wavelength conversion device is provided with at least one wavelength conversion region; The first light source is used to provide excitation light; The wavelength conversion device is disposed in the optical path of the excitation light, and is used to receive the excitation light and generate a corresponding laser beam, wherein the laser beam contains at least two of the three primary colors of the primary colors. The second light source is used to emit primary color light of a preset wavelength band, the primary color light of the preset wavelength band being different in color from the primary color light contained in the laser beam.

5. The projection display system according to claim 4, characterized in that, The second light source is a blue light source, and the wavelength conversion device includes a yellow light conversion region and a green light conversion region; The wavelength adjustment component includes a first wavelength selection element having a first cutoff wavelength and a second wavelength selection element having a second cutoff wavelength; The first wavelength selection element is used to obtain red primary color light corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device; The second wavelength selection element is used to obtain green primary color light corresponding to the second cutoff wavelength from the green fluorescence emitted by the wavelength conversion device.

6. The projection display system according to claim 4, characterized in that, The second light source is a blue light source, and the wavelength conversion device includes a yellow light conversion region; The wavelength adjustment component includes a first wavelength selection element having a first cutoff wavelength, a second wavelength selection element having a second cutoff wavelength, and a first supplementary light source; The first wavelength selection element is used to obtain red fluorescence corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device, the first supplementary light source is used to emit red light, and the red fluorescence and the red light are combined to obtain red primary color light; The second wavelength selection element is used to obtain green primary color light corresponding to the second cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device.

7. The projection display system according to claim 4, characterized in that, The second light source is a blue light source, and the wavelength conversion device includes a yellow light conversion region; The wavelength adjustment component includes a first wavelength selection element having a first cutoff wavelength, a second wavelength selection element having a second cutoff wavelength, a first supplementary light source, and a second supplementary light source; The first wavelength selection element is used to obtain red fluorescence corresponding to the first cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device, the first supplementary light source is used to emit red light, and the red fluorescence and the red light are combined to obtain red primary color light; The second wavelength selection element is used to obtain green fluorescence corresponding to the second cutoff wavelength from the yellow fluorescence emitted by the wavelength conversion device, and the second supplementary light source is used to emit green light. The green fluorescence and the green light are combined to obtain green primary color light.

8. The projection display system according to claim 1, characterized in that, The color gamut coverage of the projection display system is greater than or equal to the preset color gamut coverage.

9. The projection display system according to claim 8, characterized in that, The preset color gamut coverage is 33%.

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