Display substrate having a filter conversion layer

A display substrate includes a base substrate and a filter conversion layer disposed on the base substrate. The filter conversion layer includes a light conversion material capable of absorbing light with a wavelength less than a preset wavelength range, and converting the absorbed light into light with a wavelength in the preset wavelength range. The filter conversion layer is configured to allow the light with the wavelength in the preset wavelength range to pass through.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201810832092.8, filed with the Chinese Patent Office on Jul. 25, 2018, titled “COLOR FILM SUBSTRATE AND WOLED DISPLAY APPARATUS”, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of display technologies, and in particular, to a display substrate and a display apparatus.

BACKGROUND

In recent years, the silicon-based organic light-emitting diode (OLED) microdisplay has been widely used in the field of virtual reality (VR) and augmented reality (AR) technologies as a near-eye display.

SUMMARY

In one aspect, a display substrate is provided, including a base substrate and a filter conversion layer disposed on the base substrate. The filter conversion layer includes a light conversion material capable of absorbing light with a wavelength less than a preset wavelength range and converting the absorbed light into light with a wavelength in the preset wavelength range. The filter conversion layer is configured to allow the light with the wavelength in the preset wavelength range to pass through.

In some embodiments, stokes shift of the light conversion material is less than or equal to 20 nm.

In some embodiments, the light conversion material includes a perovskite quantum dot material.

In some embodiments, a general formula of the perovskite quantum dot material is APbX3. A is Cs or CH3NH3, and X3is selected from a group consisting of Br3, BrNI3-Nand BrNCl3-N. N is greater than or equal to 0 and less than 3.

In some embodiments, a particle diameter of the perovskite quantum dot material is in a range from 2.5 nm to 5 nm.

In some embodiments, the filter conversion layer further includes an optical filter material configured to allow light with a wavelength in a preset color wavelength range to pass through. The light conversion material is mixed in the optical filter material.

In some embodiments, a mass ratio of the light conversion material to the optical filter material is in a range from approximately 2% to approximately 5%.

In some embodiments, the optical conversion layer includes red filter conversion films, green filter conversion films and blue filter conversion films. The preset wavelength range includes a red preset wavelength range, a green preset wavelength range, and a blue preset wavelength range. The light conversion material includes a first light conversion material distributed in red filter conversion films, a second light conversion material distributed in the green filter conversion films, and a third light conversion material distributed in the blue filter conversion films. The first light conversion material is configured to absorb light with a wavelength less than the red preset wavelength range and convert the absorbed light into light with a wavelength in the red preset wavelength range. The second light conversion material is configured to absorb light with a wavelength less than the green preset wavelength range and convert the absorbed light into light with a wavelength in the green preset wavelength range. The third light conversion material is configured to absorb light with a wavelength less than the blue preset wavelength range and convert the absorbed light into light with a wavelength in the blue preset wavelength range.

In some embodiments, the red preset wavelength range is from 620 nm to 640 nm, the green preset wavelength range is from 520 nm to 540 nm, and the blue preset wavelength range is from 450 nm to 470 nm.

In some embodiments, the first light conversion material includes a CsPbBrNI3-Nperovskite quantum dot material and/or a CH3NH3PbBrNI3-Nperovskite quantum dot material. The second light conversion material includes a CsPbBr3perovskite quantum dot material and/or a CH3NH3PbBr3perovskite quantum dot material. The third light conversion material includes a CsPbBrNCl3-Nperovskite quantum dot material and/or a CH3NH3PbBrNCl3-Nperovskite quantum dot material. N is greater than or equal to 0 and less than 3.

In some embodiments, a molar mass ratio of Br and I in the first light conversion material is inversely related to a wavelength of converted light of the first light conversion material. A particle diameter of the second light conversion material is positively related to a wavelength of converted light of the second light conversion material. A molar mass ratio of Br and Cl in the third light conversion material is positively related to a wavelength of converted light of the third light conversion material.

In some embodiments, the filter conversion layer includes an optical filter film configured to allow light with a wavelength in a preset color wavelength range to pass through, and a light conversion film disposed on a side of the optical filter film proximate to or away from the base substrate. Material for manufacturing the light conversion film is the light conversion material.

In some embodiments, a thickness of the light conversion film is in a range from 0.5 μm to 2 μm.

In some embodiments, the optical filter film includes red filter sub-films, green filter sub-films and blue filter sub-films. The preset wavelength range includes a red preset wavelength range, a green preset wavelength range, and a blue preset wavelength range. The light conversion film includes red light conversion sub-films, green light conversion sub-films and blue light conversion sub-films. Each red light conversion sub-film is disposed on a side of a corresponding red filter sub-film proximate to or away from the base substrate, and material for manufacturing the red light conversion sub-films is a first light conversion material, which is configured to absorb light with a wavelength less than the red preset wavelength range and convert the absorbed light into light with a wavelength in the red preset wavelength range. Each green light conversion sub-film is disposed on a side of a corresponding green filter sub-film proximate to or away from the base substrate, and material for manufacturing the green light conversion sub-films is a second light conversion material, which is configured to absorb light with a wavelength less than the green preset wavelength range and convert the absorbed light into light with a wavelength in the green preset wavelength range. Each blue light conversion sub-film is disposed on a side of a corresponding blue filter sub-film proximate to or away from the base substrate, and material for manufacturing the blue light conversion sub-films is a third light conversion material, which is configured to absorb light with a wavelength less than the blue preset wavelength range and convert the absorbed light into light with a wavelength in the blue preset wavelength range.

In some embodiments, the red preset wavelength range is from 620 nm to 640 nm, the green preset wavelength range is from 520 nm to 540 nm, and the blue preset wavelength range is from 450 nm to 470 nm.

In some embodiments, the first light conversion material includes a CsPbBrNI3-Nperovskite quantum dot material and/or a CH3NH3PbBrNI3-Nperovskite quantum dot material. The second light conversion material includes a CsPbBr3perovskite quantum dot material and/or a CH3NH3PbBr3perovskite quantum dot material. The third light conversion material includes a CsPbBrNCl3-Nperovskite quantum dot material and/or a CH3NH3PbBrNCl3-Nperovskite quantum dot material. N is greater than or equal to 0 and less than 3.

In some embodiments, a molar mass ratio of Br and I in the first light conversion material is inversely related to a wavelength of converted light of the first light conversion material. A particle diameter of the second light conversion material is positively related to a wavelength of converted light of the second light conversion material. A molar mass ratio of Br and Cl in the third light conversion material is positively related to a wavelength of converted light of the third light conversion material.

In some embodiments, the display substrate further includes white organic light emitting diode (WOLED) devices disposed between the base substrate and the filter conversion layer. Each WOLED device includes an anode, a microcavity adjustment layer, an organic light emitting layer and a cathode.

In another aspect, a display apparatus is provided, including the display substrates described above.

DETAILED DESCRIPTION

The silicon-based OLED microdisplay can be used in a wide range of temperature, and with the maturity of the complementary metal oxide semiconductor (CMOS) technology, the silicon-based OLED microdisplay can achieve ultra-high pixel display.

However, at present, low brightness of the silicon-based OLED microdisplay limits its application in VR, AR and mixed reality (MR) technologies, so the development of a high-brightness silicon-based OLED microdisplay is one of the main tendencies.

In the related art, the brightness of the silicon-based OLED microdisplay is enhanced by using the strong microcavity effect, that is, light is reinforced in the microcavity due to interference. However, this causes a blue shift in the position of the emission peak of the light. Then, after the light passes through the optical filter film, the blue shift of the wavelength of the light due to the strong microcavity effect is directly translated into a deviation in a chromaticity coordinate, which leads to a more serious visual color cast problem, affecting the display effect of the OLED microdisplay seriously.

Referring toFIG. 1andFIG. 2, some embodiments of the present disclosure provide a display substrate1, and the display substrate1includes a base substrate20and a filter conversion layer10disposed on the base substrate20. The filter conversion layer10includes a light conversion material11, and the light conversion material11is capable of absorbing light with a wavelength less than a preset wavelength range and converting the absorbed light into light with a wavelength in the preset wavelength range. The filter conversion layer10is configured to allow light with the wavelength in the preset wavelength range to pass through.

The light conversion material11is a material which, after being irradiated by light with a wavelength, emits light with a new wavelength. Here, the specific type of the light conversion material11is not limited, as long as the light conversion material11can absorb light with a wavelength less than the preset wavelength range and convert the absorbed light into light with a wavelength in the preset wavelength range.

Regarding the preset wavelength range, those skilled in the art may set it according to the wavelength of the light to be obtained after conversion, and then a suitable light conversion material11may be selected according to the wavelength of the light to be absorbed and the preset wavelength range.

Since the light conversion material11in the filter conversion layer10may absorb light with a wavelength less than the preset wavelength range and convert the absorbed light into light with a wavelength in the preset wavelength range, the emission spectrum, which moves toward the short wavelength with the increase of the viewing angle, may be corrected to the position of the emission peak corresponding to the front viewing angle as much as possible. In this way, the visual color cast due to strong microcavity effect may be reduced and the display effect of the display substrate is improved.

In some examples, the base substrate20is a silicon-based base substrate. In some other examples, the base substrate20is a base substrate made of other materials, such as a glass base substrate. In addition, the base substrate20may include driving circuit structures, and each driving circuit structure is configured to drive a corresponding light emitting device (such as a white OLED (WOLED) device30, as shown inFIG. 3) in the display substrate1to emit light.

Referring toFIG. 3andFIG. 4, the display substrate1further includes WOLED devices30disposed between the base substrate20and the filter conversion layer10. Each WOLED device30includes an anode31and a microcavity adjustment layer32, an organic light-emitting layer33and a cathode34.

As shown inFIG. 4, thicknesses of three microcavity adjustment layers32corresponding to three sub-pixels of R, G, and B are different, and thus the microcavity resonance periods of the three microcavity adjustment layers32are different. The strong microcavity effect can be utilized to enhance the luminous intensity of the three sub-pixels of R, G and B, and the luminous intensities of the three sub-pixels of R, G and B may achieve their respective required luminous intensities.

If the display substrate1does not include the filter conversion layer10, this microcavity structure may make the visual color cast problem more serious. For example, taking red light as an example, a wavelength of the red light is in a range from 620 nm to 640 nm. Due to the strong microcavity effect, as the viewing angle increases, the position of the emission peak of the red light will be blue-shifted, that is, red light with a wavelength in a range from 600 nm to 620 nm will be generated.FIG. 5shows the spectra of red light at different viewing angles. Each curve in the figure corresponds to a different viewing angle. Light corresponding to the short-wavelength spectra marked by the dotted circle is stray light, which can be filtered by the red filter film, and thus the stray light will not have a big influence on the visual color cast of the display substrate. However, the wavelengths of the luminosity curve on the right of the dotted circle are basically located in the permeable range of the red filter film. After light with these wavelengths passes through the filter film, the blue shift of the wavelength due to the strong microcavity effect may be directly translated into the deviation in the chromaticity coordinates.

However, in the embodiments of the present disclosure, the red light with a wavelength in the wavelength range from 600 nm to 620 nm is absorbed by the light conversion material11in the filter conversion layer10, and the absorbed light is converted into red light with a wavelength in the wavelength range from 620 nm to 640 nm. Therefore, the blue shift of the spectrum due to the strong microcavity effect may be corrected. Moreover, since the light with short-wavelengths far from the emission peak may be directly filtered by the optical filter film, the light conversion material11is not required to absorb the light with short-wavelengths. In this case, the light conversion material11only needs to absorb and convert the short-wavelength light proximate to the emission peak. Therefore, in some embodiments, the light conversion material11having stokes shift less than or equal to 20 nm is selected to meet the requirements of light conversion.

In some embodiments, the light conversion material11includes a perovskite quantum dot material. For example, the general formula of the perovskite quantum dot material is APbX3. Pb is plumbum, A is caesium (Cs) or CH3NH3, and X3is selected from a group consisting of Bra, BrNI3-Nand BrNCl3-N. N is greater than or equal to 0 and less than 3. In this way, the light conversion material11is allowed to have a conversion effect from high energy to low energy.

As shown inFIG. 6, taking light of four colors A, B, C, and D as an example, the upper portion of the figure shows the absorption spectra of the light conversion material11, and the lower portion shows the emission spectra of the light conversion material11. As can be seen fromFIG. 6, the light conversion material11has a conversion effect from high energy to low energy, that is, the light conversion material11may absorb light with short-wavelengths and convert the light into light with long-wavelengths. In addition, disordered light waves may be converted into neat light waves, so that it is not easy to cause chromatic aberration after the light of four colors A, B, C, and D are converted. Therefore, the emission spectrum, which moves toward the short wavelength with the increase of the viewing angle, may be corrected to the position of the emission peak of the front viewing angle as much as possible. In this way, the visual color cast due to the strong microcavity effect is reduced and the display effect of the display substrate is improved.

There are a plurality of ways to provide the filter conversion layer10including the light conversion material11, including but not limited to the embodiments shown below.

In some embodiments, referring toFIG. 1, the filter conversion layer10includes an optical filter material15and the light conversion material11. The optical filter material15is configured to allow light with a wavelength in a preset color wavelength range to pass through, and the light conversion material11is mixed in the optical filter material15.

The optical filter material15is not limited herein, which can be selected by those skilled in the art from existing filter materials according to the needed wavelengths.

In addition, a mass ratio of the light conversion material11to the optical filter material15is not limited, which can be set by those skilled in the art according to actual conditions. In some embodiments, the mass ratio of the light conversion material11to the optical filter material15is in a range from approximately 2% to approximately 5%, which may better meet the requirements of light conversion.

In some embodiments, referring again toFIG. 1, the filter conversion layer10includes red filter conversion films101, green filter conversion films102, and blue filter conversion films103. Each red filter conversion film101allows red light to pass through, each green filter conversion film102allows green light to pass through, and each blue filter conversion film103allows blue light to pass through.

The preset wavelength range includes a red preset wavelength range, a green preset wavelength range, and a blue preset wavelength range. The light conversion material11includes a first light conversion material111, a second light conversion material112, and a third light conversion material113.

The first light conversion material111is distributed in the red filter conversion films101, and is configured to absorb light with a wavelength less than the red preset wavelength range, and convert the absorbed light into light with a wavelength in the red preset wavelength range.

In some embodiments, the first light conversion material111distributed in the red filter conversion films101includes a CsPbBrNI3-Nperovskite quantum dot material. In some other embodiments, the first light conversion material111distributed in the red filter conversion films101includes a CH3NH3PbBrNI3-Nperovskite quantum dot material. In some other embodiments, the first light conversion material111distributed in the red filter conversion films101includes the CsPbBrNI3-Nperovskite quantum dot material and the CH3NH3PbBrNI3-Nperovskite quantum dot material.

The red preset wavelength range is from 620 nm to 640 nm, that is, the emission peak of the first light conversion material111is between 620 nm and 640 nm, and the first light conversion material111can absorb light with a wavelength less than 620 nm and convert the absorbed light into light with a wavelength in a range from 620 nm to 640 nm.

In some embodiments, a molar mass ratio of Br and I in the first light conversion material111is inversely related to a wavelength of the converted light. Therefore, the wavelength of the light emitted from the first light conversion material111can be adjusted by adjusting the molar mass ratio of Br and I. For example, the molar mass ratio of Br and I is decreased to increase the wavelength of the light emitted from the light conversion material11. For another example, the molar mass ratio of Br and I is increased to reduce the wavelength of the light emitted from the light conversion material11. For example, in a case where the first light conversion material111is the CH3NH3PbBrNI3-Nperovskite quantum dot material, and N=0.8, that is, in a case where the first light conversion material111is CH3NH3PbBr0.8I2.2, the wavelength of the converted light emitted from the first light conversion material111is 628 nm.

The second light conversion material112is distributed in the green filter conversion films102, and the second light conversion material112is configured to absorb light with a wavelength less than the green preset wavelength range, and convert the absorbed light into light with a wavelength in the green preset wavelength range.

In some embodiments, the second light conversion material112distributed in the green filter conversion films102includes a CsPbBr3perovskite quantum dot material. In some other embodiments, the second light conversion material112distributed in the green filter conversion films102includes a CH3NH3PbBr3perovskite quantum dot material. In some other embodiments, the second light conversion material112distributed in the green filter conversion films102includes the CsPbBr3perovskite quantum dot material and the CH3NH3PbBr3perovskite quantum dot material.

In some embodiments, the green preset wavelength range is from 520 nm to 540 nm. That is, the emission peak of the second light conversion material112is between 520 nm and 540 nm, and the second light conversion material112can absorb light with a wavelength less than 520 nm and convert the absorbed light into light with a wavelength in the range from 520 nm to 540 nm.

In some embodiments, a particle diameter of the second light conversion material112is positively related to a wavelength of the converted light. Therefore, the wavelength of the light emitted from the second light conversion material112can be adjusted by adjusting the particle diameter of the quantum dot material. For example, the particle diameter of the perovskite quantum dot material is increased to increase the wavelength of the converted light emitted from the second light conversion material112. For another example, the particle diameter of the perovskite quantum dot material is decreased to reduce the wavelength of the converted light emitted from the second light conversion material112. For example, in a case where the second light conversion material112is the CH3NH3PbBr3perovskite quantum dot material and the particle diameter is 4 nm, the wavelength of the converted light emitted from the second light conversion material112is 525 nm.

In some embodiments, the third light conversion material113is distributed in the blue filter conversion films103, and the third light conversion material113is configured to absorb light with a wavelength less than the blue preset wavelength range, and convert the absorbed light into light with a wavelength in the blue preset wavelength range.

In some embodiments, the third light conversion material113distributed in the blue filter conversion films103includes a CsPbBrNCl3-Nperovskite quantum dot material. In some other embodiments, the third light conversion material113distributed in the blue filter conversion films103includes a CH3NH3PbBrNCl3-Nperovskite quantum dot material. In some other embodiments, the third light conversion material113distributed in the blue filter conversion films103includes the CsPbBrNCl3-Nperovskite quantum dot material and the CH3NH3PbBrNCl3-Nperovskite quantum dot material.

In some embodiments, the blue preset wavelength range is from 450 nm to 470 nm. That is, the emission peak of the third light conversion material113is between 450 nm and 470 nm, and the third light conversion material113can absorb light with a wavelength less than 450 nm and convert the absorbed light into light with a wavelength in a range from 450 nm to 470 nm.

In some embodiments, a molar mass ratio of Br and Cl in the third light conversion material is positively related to a wavelength of the converted light. That is, the emission wavelength of the third light conversion material113can be adjusted by adjusting the molar mass ratio of Br and Cl. For example, the molar mass ratio of Br and Cl is increased to increase the wavelength of the converted light emitted from the third light conversion material113. For another example, the molar mass ratio of Br and Cl is decreased to reduce the wavelength of the converted light emitted from the third light conversion material113. For example, In a case where the third light conversion material113is the CH3NH3PbBrNCl3-Nperovskite quantum dot material, and N=2.4, that is, in a case where the third light conversion material113is a CH3NH3PbBr2.4Cl0.6perovskite quantum dot material, the wavelength of the converted light emitted from the third light conversion material113is 465 nm.

In the above embodiments, N is greater than or equal to 0 and less than 3.

In some examples, a particle diameter of the above perovskite quantum dot material is in a range from 2.5 nm to 5 nm.

In some other embodiments, referring toFIG. 2, the filter conversion layer10includes an optical filter film12and a light conversion film13. The optical filter film12is configured to allow light with a wavelength in the preset color wavelength range to pass through, and the light conversion film13is disposed on a side of the optical filter film12proximate to or away from the base substrate20(FIG. 2shows a case where the light conversion film13is disposed on a side of the optical filter film12proximate to the base substrate20). The light conversion film13is made of the light conversion material11.

Here, a thickness of the light conversion film13is not limited, which can be set by those skilled in the art according to actual conditions. In some embodiments, the thickness of the light conversion film13is in a range from 0.5 μm to 2 μm, which may better meet the requirements of light conversion.

For example, as shown inFIG. 2, the optical filter film12includes red filter sub-films121, green filter sub-films122, and blue filter sub-films123. Each red filter sub-film121allows red light to pass through, each green filter sub-film122allows green light to pass through, and each blue filter sub-film123allows blue light to pass through.

The preset wavelength range includes the red preset wavelength range, the green preset wavelength range, and the blue preset wavelength range. The light conversion film13includes red light conversion sub-films131, green light conversion sub-films132, and blue light conversion sub-films133.

Each red light conversion sub-films131is disposed on a side of a corresponding second red filter sub-film121proximate to or away from the base substrate20(FIG. 2shows a case where the red light conversion sub-film131is disposed on a side of the second red filter sub-film121proximate to the base substrate20). Material for manufacturing the red light conversion sub-films131is the first light conversion material111, and the first light conversion material111is configured to absorb light with a wavelength less than the red preset wavelength range, and convert the absorbed light into light with a wavelength in the red preset wavelength range.

In some embodiments, as shown inFIG. 2, each red light conversion sub-film131is disposed on a light incident side of a corresponding second red filter sub-film121, that is, each red light conversion sub-film131is disposed on a side of a corresponding red filter film121proximate to the base substrate20. In this way, after light is converted by the red light conversion sub-film131, the second red filter sub-film121may filter the converted light, so that when a conversion error occurs and variegated light is generated, the variegated light may be effectively filtered.

In some embodiments, the material of the red light conversion sub-films131(i.e., the first light conversion material111) includes a CsPbBrNI3-Nperovskite quantum dot material. In some other embodiments, the material of the red light conversion sub-films131(i.e., the first light conversion material111) includes a CH3NH3PbBrNI3-Nperovskite quantum dot material. In some embodiments, the material of the red light conversion sub-films131(i.e., the first light conversion material111) includes the CsPbBrNI3-Nperovskite quantum dot material and the CH3NH3PbBrNI3-Nperovskite quantum dot material.

The red preset wavelength range is from 620 nm to 640 nm, that is, the emission peak of the first light conversion material111is between 620 nm and 640 nm, and the first light conversion material111can absorb light with a wavelength less than 620 nm and convert the absorbed light to light with a wavelength in a range of 620 nm to 640 nm.

In some embodiments, the molar mass ratio of Br and I in the first light conversion material111is inversely related to a wavelength of the converted light. Therefore, the wavelength of the light emitted from the first light conversion material111can be adjusted by adjusting the molar mass ratio of Br and I. For example, the molar mass ratio of Br and I is decreased to increase the wavelength of light emitted from the first light conversion material111. For another example, the molar mass ratio of Br and I is increased to reduce the wavelength of light emitted from the first light conversion material111. For example, in a case where the first light conversion material111is a CH3NH3PbBrNI3-Nperovskite quantum dot material, and N=0.8, that is, in a case where the first light conversion material111is CH3NH3PbBr0.8I22, the wavelength of the converted light of the first light conversion material111is 628 nm.

Each green light conversion sub-films132is disposed on a side of a corresponding second green filter sub-films122proximate to or away from the base substrate20(FIG. 2shows a case where the green light conversion sub-film132is disposed on a side of the second green filter sub-films122proximate to the base substrate20). Material for manufacturing the green light conversion sub-films132is the second light conversion material112, and the second light conversion material112is configured to absorb light with a wavelength less than the green preset wavelength range, and convert the absorbed light into light with a wavelength in the green preset wavelength range.

In some embodiments, as shown inFIG. 2, each green light conversion sub-film132is disposed on a light incident side of a corresponding second green filter sub-film122, that is, each green light conversion sub-films132is disposed on a side of a corresponding green filter film122proximate to the base substrate20. In this way, after light is converted by the green light conversion sub-film132, the second green filter sub-film122may filter the converted light, so that when a conversion error occurs and variegated light is generated, the variegated light may be effectively filtered.

In some embodiments, the material of the green light conversion sub-films132(i.e., the second light conversion material112) includes a CsPbBr3perovskite quantum dot material. In some other embodiments, the material of the green light conversion sub-films132(i.e., the second light conversion material112) includes a CH3NH3PbBr3perovskite quantum dot material. In some other embodiments, the material of the plurality of green light conversion sub-films132(i.e., the second light conversion material112) includes a CsPbBr3perovskite quantum dot material and a CH3NH3PbBr3perovskite quantum dot material.

In some embodiments, the green preset wavelength range is from 520 nm to 540 nm, that is, the emission peak of the second light conversion material112is between 520 nm and 540 nm, and the second light conversion material112may absorb light with a wavelength less than 520 nm and convert the absorbed light into light with a wavelength in a range from 520 nm to 540 nm.

In some embodiments, a particle diameter of the second light conversion material112is positively related to a wavelength of the converted light. Therefore, the wavelength of the light emitted from the second light conversion material112can be adjusted by adjusting the particle diameter of the quantum dot material. For example, the particle diameter of the perovskite quantum dot material is increased to increase the wavelength of the converted light of the second light conversion material112. For another example, the particle diameter of the perovskite quantum dot material is decreased to reduce the wavelength of the converted light of the second light conversion material112. For example, in a case where the second light conversion material112is a CH3NH3PbBr3perovskite quantum dot material and the particle diameter is 4 nm, the wavelength of the converted light of the second light conversion material112is 525 nm.

Each blue light conversion sub-films133is disposed on a side of a corresponding second blue filter sub-film123proximate to or away from the base substrate20(FIG. 2shows a case where the blue light conversion sub-film133is disposed on a side of the second blue filter sub-film123proximate to the base substrate20). Material for manufacturing the blue light conversion sub-films133is the third light conversion material113, and the third light conversion material113is configured to absorb light with a wavelength less than the blue preset wavelength range, and convert the absorbed light into light with a wavelength in the blue preset wavelength range.

In some embodiments, as shown inFIG. 2, each blue light conversion sub-film133is disposed on a light incident side of a corresponding second blue filter sub-film123, that is, each blue light conversion sub-films133is disposed on a side of a corresponding blue filter film123proximate to the base substrate20. In this way, after light is converted by the blue light conversion sub-film133, the second blue filter sub-film123may filter the converted light, so that when a conversion error occurs and variegated light is generated, the variegated light may be effectively filtered.

In some embodiments, the material of the blue light conversion sub-films133(i.e., the third light conversion material113) includes a CsPbBrNCl3-Nperovskite quantum dot material. In some other embodiments, the material of the blue light conversion sub-films133(i.e., the third light conversion material113) includes a CH3NH3PbBrNCl3-Nperovskite quantum dot material. In some other embodiments, the material of the blue light conversion sub-films133(i.e., the third light conversion material113) includes the CsPbBrNCl3-Nperovskite quantum dot material and the CH3NH3PbBrNCl3-Nperovskite quantum dot material.

In some embodiments, the blue preset wavelength range is from 450 nm to 470 nm, that is, the emission peak of the third light conversion material113is between 450 nm and 470 nm, and the third light conversion material113can absorb light with a wavelength less than 450 nm and convert the absorbed light into light with a wavelength in a range from 450 nm to 470 nm.

In some embodiments, a molar mass ratio of Br and Cl in the third light conversion material is positively related to the wavelength of the converted light. That is, the emission wavelength of the third light conversion material113can be adjusted by adjusting the molar mass ratio of Br and Cl. For example, the molar mass ratio of Br and Cl is increased to increase the wavelength of the converted light of the third light conversion material113. For another example, the molar mass ratio of Br and Cl is decreased to reduce the wavelength of the converted light of the third light conversion material113. For example, in a case where the third light conversion material113is a CH3NH3PbBrNCl3-Nperovskite quantum dot material, and N=2.4, that is, in a case where the third light conversion material113is a CH3NH3PbBr24Cl06perovskite quantum dot material, the wavelength of the converted light of the third light conversion material113is 465 nm.

In the above embodiments, N is greater than or equal to 0 and less than 3.

In some examples, a particle diameter of the perovskite quantum dot material is in a range from 2.5 nm to 5 nm.

In some embodiments, referring toFIGS. 1-3, the display substrate1further includes a black matrix14disposed on the base substrate20. By setting the black matrix14, the cross color may be prevented from producing between the adjacent two optical filter films, which improves the display effect.

Referring toFIG. 7, some embodiments of the present disclosure provide a display apparatus2including the display substrate1in any one of the above embodiments.

In some embodiments, the display apparatus further includes an encapsulation layer40disposed on a side of the filter conversion layer10away from the base substrate20, to prevent water oxygen from eroding the filter conversion layer10and the WOLED devices30.

In the above display substrate1, since the filter conversion layer10includes the light conversion material11, which has a conversion effect from high energy to low energy, the filter conversion layer10can absorb light with short wavelengths, and convert it into light with long wavelengths. Therefore, the emission spectrum, which moves toward the short wavelength with the increase of the viewing angle, may be corrected to the position of the emission peak of the front viewing angle as much as possible. In this way, the visual color cast due to the strong microcavity effect is reduced and the display effect of the display substrate is improved.

For example, the display apparatus2includes, but is not limited to, a silicon-based display apparatus, such as a silicon-based top emission display apparatus.