[0025] The technical solution of the present invention will be further described below in conjunction with the drawings and embodiments.
[0026] Such as figure 1 with figure 2 As shown, the infrared-visible light image up-conversion device based on semiconductor quantum dots and liquid crystals of the present invention includes an upper substrate 11, a visible light shielding layer 10, an infrared transparent electrode 9, a semiconductor quantum dot photoelectric active layer 8, and visible light from top to bottom. The light-reflecting layer 7, the upper liquid crystal alignment layer 6, the liquid crystal layer 5, the lower liquid crystal alignment layer 4, the visible light transparent electrode 3, the lower substrate 2 and the polarizing plate 1. Among them, 1 to 6 constitute visible light image display component 13, which is a visible light image display part based on liquid crystal; 6 to 11 constitute infrared image detection component 12, which is an infrared image detection part based on semiconductor quantum dots. The infrared transparent electrode 9 and the visible light transparent electrode 33 are respectively connected to two electrodes of the AC driving power source.
[0027] Infrared image detection component 12, infrared light is incident on the semiconductor quantum dot active layer 8 from top to bottom, and the infrared photon signal is converted into a charge signal and stored in the liquid crystal lower alignment layer 6; visible light image display component 13, irradiated light enters from bottom to top The visible light image display component 13 converts the charge signal stored in the lower alignment layer 6 of the liquid crystal into a visible light intensity signal.
[0028] The upper substrate 11 is made of a material that absorbs less infrared photons, and is an infrared transparent glass substrate or a flexible plastic substrate. The visible light shielding layer 10 needs to be able to transmit infrared photons, but must block visible photons to prevent visible light from interfering with infrared images. The semiconductor quantum dot active photoelectric layer 8 is quantum dots such as Pbs, PbSe, and HgTe, and its band gap is less than 1.55eV (800nm infrared photon energy). These semiconductor quantum dots can absorb infrared photons and generate electron-hole pairs through the photoelectric effect. . The visible light reflection layer 7 can completely reflect the irradiated visible light transmitted from below, so as to prevent the visible light from affecting the upper quantum dot photoelectric conversion layer. The visible light image display component 13 is essentially a reflective liquid crystal display device, and the electric field applied on the liquid crystal layer is regulated by the accumulation of electric charges generated by the infrared image detection component 12. The transparent electrode is a transparent indium tin oxide (ITO) electrode or a fluorine-doped tin oxide (FTO) electrode.
[0029] Such as figure 1 with figure 2 As shown, the method for preparing an infrared-visible image up-conversion device based on semiconductor quantum dots and liquid crystals of the present invention includes:
[0030] (1) The visible light shielding layer 10 is prepared by sputtering on the upper substrate 11, the infrared transparent electrode 9 is prepared by evaporation or sputtering on the visible light shielding layer 10, and the semiconductor quantum dot photoelectric is prepared by spin coating on the infrared transparent electrode 9 The active layer 8 is further evaporated on the semiconductor quantum dot photoelectric active layer 8 to prepare a visible light reflective layer 7, further spin-coated on the visible light reflective layer 7 to prepare a liquid crystal alignment layer, and further align the liquid crystal alignment layer by rubbing or light-controlled alignment. Obtain the upper alignment layer 6 of the liquid crystal;
[0031] (2) Sputtering the upper surface of the lower substrate 2 to prepare a visible light transparent electrode 3, such as ITO and FTO, and then spin coating on the visible light transparent electrode 3 to prepare a liquid crystal alignment layer, and further align the liquid crystal alignment layer by rubbing or light-controlled alignment methods , Obtain the liquid crystal lower alignment layer 4;
[0032] (3) Combine the upper substrate 11 and the lower substrate 2 to form a liquid crystal cell, and use a conventional crystal filling method to infuse liquid crystal to form the liquid crystal layer 5;
[0033] (4) The polarizer 1 is assembled on the lower surface of the lower substrate 2 to form an infrared-visible image upconversion device.
[0034] The invention is based on the imaging method of semiconductor quantum dots and liquid crystal infrared-visible image up-conversion devices. When infrared light is irradiated to the infrared image detection component 12 from top to bottom, the semiconductor quantum dots are photoelectrically activated according to the different intensities of infrared light in different regions. The layer 8 generates different photo-generated currents in the corresponding areas. The photo-generated current aligns the layer 6 on the liquid crystal to form a charge distribution corresponding to the infrared image; the charge distribution generated by the infrared image forms a corresponding spatial electric field distribution in the visible light display part, and further The electro-optical performance of the liquid crystal layer is regulated. After the visible light passes through the regulated liquid crystal layer, it is reflected by the reflective layer to form a visible light image display, which realizes the up-conversion of infrared images to visible light images.
[0035] Such as image 3 with Figure 4 As shown, the physical process of the infrared-visible image up-conversion device based on semiconductor quantum dots and liquid crystals of the present invention is that when infrared photons are incident on the photoelectric active layer 8 of the semiconductor quantum dots, photo-generated electrons are generated due to the photoelectric effect of the quantum dot infrared photoelectric conversion layer Hole pair. Assuming that the potential applied to the infrared transparent electrode 9 is positive at this time, the voltage applied to the visible light transparent electrode 3 is negative, the photo-generated electron-hole pair is under the bias electric field, the photo-generated electron drifts to the infrared transparent electrode 9, and the photo-generated hole The visible light transparent electrode 3 drifts. The visible light reflective layer 7 and the upper alignment layer 6 of the liquid crystal are dielectric layers, and the light-generated holes are blocked by the dielectric layer during the drift process to generate charge accumulation. The amount of charge accumulated on the dielectric layer corresponds to the intensity of incident infrared photons. These accumulated charges can also control the electric field distribution of the liquid crystal layer 5, further adjust the alignment of the liquid crystal molecules, and control the intensity of visible light emitted by the polarizer 1 to reduce infrared The image is converted to a visible light image.
[0036] In order to avoid damage to the liquid crystal molecules caused by long-term charge accumulation, an alternating power supply is applied so that the polarity of the electric field between the infrared transparent electrode 9 and the visible light transparent electrode 3 is periodically reversed over time. When the potential of the infrared transparent electrode 9 is negative and the potential of the visible light transparent electrode 3 is positive, after the photoelectric active layer 8 of the semiconductor quantum dot absorbs infrared photons, the photo-generated holes drift upward, and the photo-generated electrons drift downward. The photo-generated electrons are accumulated on the dielectric layer, and the aforementioned liquid crystal electro-optical characteristics control is also produced through the charge accumulation.
[0037] The invention uses colloidal semiconductor quantum dots as a photoelectric conversion material to absorb infrared photon signals to generate photogenerated electron/hole pairs; using the characteristics of the preparation of the colloidal semiconductor quantum dot detector solution method, the semiconductor quantum dot photoelectric active layer and reflective liquid crystal display Partial integration, through the accumulation of photo-generated carriers, realizes the regulation of the electro-optical characteristics of the liquid crystal layer, and finally obtains the visible light image corresponding to the infrared image. The up-conversion device structure does not require pixel patterning preparation, and does not require a special detection signal readout circuit and display signal drive circuit, the device structure is compact, the preparation process is simple, and the preparation cost is low.
