TWI581246B - Method for driving electrochromic device and method for determining bleaching voltage - Google Patents

Description

Driving method of electrochromic element and method for determining fading voltage

The present invention relates to a method of driving an electronic component driven by a voltage, and more particularly to a method of driving an electrochromic element and a method of determining a fading voltage of the electrochromic element.

Electrochromic devices (ECDs) have low drive voltage and bistable characteristics. Under the action of the applied voltage, the electrochromic element undergoes a stable and reversible color change phenomenon. In addition, different electrochromic materials, electrochromic electrolytes, or a combination of the two may be used depending on different environmental requirements to cause the electrochromic elements to produce different color changes. A variety of electrochromic components have been used in automotive sunroofs and anti-glare rearview mirrors, aircraft viewing windows, energy-saving smart windows and architectural glass in architectural technology to achieve changes in ambient light intensity through the mechanism of color change of electrochromic components. The purpose of artificial illumination modulation and/or anti-theft is to provide a light intelligent modulation solution to provide situational light source, improve visual presentation and solve environmental light pollution.

The electrochromic element can be slowly discolored without being applied with a voltage after being driven by a suitable driving voltage. In the prior art, the process of fading can be accelerated by applying a fade voltage applied to the electrochromic element in opposition to the drive voltage. However, the prior art does not address solutions for how to determine and apply the correct reverse fade voltage.

The present application provides a method of driving an electrochromic element and a method of determining a fading voltage.

An embodiment of the present application provides a driving method of an electrochromic element, comprising the steps of: applying a sensing voltage that varies within a voltage interval to an electrochromic element to sense that the electrochromic element begins to change color. a threshold voltage corresponding to the time, and the threshold voltage value falls within the voltage interval; a fade voltage is determined according to the threshold voltage value; after the threshold voltage value is sensed, a driving voltage is applied to the electrochromic An element to discolor the electrochromic element; and a fading voltage applied to the electrochromic element to accelerate fading of the electrochromic element.

Another embodiment of the present application provides a method for determining a fade voltage suitable for determining a fade voltage of a discolored electrochromic element, the method comprising: applying a sense voltage that varies within a voltage interval to electricity The color-changing element senses a threshold voltage corresponding to the start of discoloration of the electrochromic element, and the threshold voltage value falls within the voltage range; and the fade voltage is determined according to the threshold voltage value.

Based on the above, the above embodiment of the present application senses the threshold voltage value corresponding to when the electrochromic element starts to change color by applying a sensing voltage that varies within a specific voltage interval to the electrochromic element, and According to the threshold voltage value, an appropriate fading voltage is determined, thereby accelerating the fading of the electrochromic element.

The above described features and advantages of the invention will be apparent from the following description.

1A to 1C are respectively schematic cross-sectional views of the electrochromic element in an embodiment of the present application after being driven to change color, after being driven to change color, and after applying a fading voltage. As shown in FIGS. 1A to 1C, the electrochromic element 100 of the present embodiment includes a first electrode layer 130, a second electrode layer 140, an electrolyte layer 150, and an electrochromic material 160, wherein the electrolyte layer 150 and electrochromic The material 160 is located between the first electrode layer 130 and the second electrode layer 140. In the present embodiment, the electrochromic element 100 may further include a first substrate 110 and a second substrate 120, wherein the first electrode layer 130 is located between the first substrate 110 and the electrochromic material 160, and The second electrode layer 140 is located between the second substrate 120 and the electrochromic material 160. In other words, the first substrate 110 and the second substrate 120 are used to carry the first electrode layer 130, the second electrode layer 140, and the electrolyte layer 150 and the electrochromic material 160 between the first electrode layer 130 and the second electrode layer 140. . In this embodiment, the first substrate 110 and the second substrate 120 may be rigid substrates or flexible substrates, and the first substrate 110 and the second substrate 120 are, for example, glass substrates or plastic substrates. However, the embodiment is not limited thereto.

The first electrode layer 130 and the second electrode layer 140 in the electrochromic element 100 may adopt different designs depending on the field of application of the electrochromic element 100 and its type. In one embodiment, the first electrode layer 130 and the second electrode layer 140 are transparent conductive layers, and the materials of the first electrode layer 130 and the second electrode layer 140 are, for example, indium tin oxide (ITO), indium zinc oxide. (IZO) or aluminum zinc oxide (AZO), etc., but the application is not limited thereto. In another embodiment, one of the first electrode layer 130 and the second electrode layer 140 is a transparent conductive layer, and the other of the first electrode layer 130 and the second electrode layer 140 is an opaque conductive layer. For example, the first electrode layer 130 may be a transparent conductive layer, and the second electrode layer 140 may be an opaque conductive layer (eg, a reflective electrode); or the first electrode layer 130 may be an opaque conductive layer (eg, a reflective electrode), The second electrode layer 140 can be a transparent conductive layer. As shown in FIGS. 1A to 1C, the driving of the electrochromic element 100 can be achieved by a voltage V applied between the first electrode layer 130 and the second electrode layer 140.

The electrolyte layer 150 is usually composed of a conductive ion material such as lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ) or a solid electrolyte, and the present application is not limited thereto. The electrochromic material 160 includes an inorganic material or an organic material. The inorganic material is, for example, a material such as tungsten trioxide (WO ₃ ) or a covalent metal complex Prussian Blue (Fe ₄ [Fe(CN) ₆ ] ₃ ), and the organic material is, for example, Viologen or poly Materials such as polyethylenedioxythiophene (PEDOT), but the application is not limited thereto.

Referring to FIG. 1A and FIG. 1B, when the electrochromic element 100 of the present embodiment is not driven, its state is as shown in FIG. 1A. When the electrochromic element 100 is driven to start operation, a driving voltage is applied between the first electrode layer 130 and the second electrode layer 140 to cause the electrochromic material 160 to undergo redox under the applied driving voltage. The reaction, in turn, causes a change in the color of the electrochromic material 160.

The electrolyte layer 150 may also be made of a second electrochromic material that is electrically opposite to the electrochromic material 160 such that the color of the electrolyte layer 150 changes simultaneously as the electrochromic material 160 undergoes a color change, such that A color addition or complementation is achieved between the electrolyte layer 150 and the electrochromic material 160. For example, if the electrochromic material 160 is an oxidized color changing material, the electrolyte layer 150 may be used as a second electrochromic material using a reduced color changing material. When a driving voltage is applied to the electrochromic material 160 and the electrolyte layer 150 through the first electrode 130 and the second electrode 140, the electrochromic material 160 is discolored by oxidation, and the electrolyte layer 150 is discolored by reduction. The driving method proposed in the application is not limited to this.

Continuing to refer to FIG. 1A and FIG. 1B, after the electrochromic element 100 is driven to change color, if the application of voltage to the discolored electrochromic element 100 is stopped, the electrochromic element 100 will slowly fade to form as depicted in FIG. 1A. State of the show. After the electrochromic element 100 is driven to be discolored, if the fading voltage opposite to the driving voltage is applied to the discolored electroluminescent element 100, the electroluminescent element 100 can be accelerated to fade.

Referring to FIG. 1C, after the electrochromic element 100 is driven to change color, if an excessive reverse voltage is applied to the discolored electroluminescent element 100, the electroluminescent element 100 is further changed during the fading process. colour. Specifically, the driving voltage applied to the electrochromic element 100 causes the electrochromic material 160 to be reacted into a colored compound adjacent to the second electrode layer 140 (as shown in FIG. 1B); if a reverse voltage is applied (i.e., fading voltage) causes the electrochromic element 100 to begin to fade, and during the fading of the electroluminescent element 100, if the aforementioned applied fading voltage is excessive, the electrochromic material 160 will be adjacent to the first electrode layer. At 130, it is reacted into a colored compound, which in turn causes the electroluminescent element 100 to further change color during the fading process, resulting in a decrease in the fading speed of the electroluminescent element 100.

2 is a graph showing the transmittance of an electrochromic element as a function of time in an embodiment of the present application. Referring to FIG. 2, after the electrochromic element 100 is driven to change color (for example, the light transmittance is lowered), if the fading voltage is not applied to the electrochromic element 100, the transmittance of the electrochromic element 100 changes as curve 210. As shown, after the electrochromic element 100 is driven to change color, if a suitable fading voltage is applied to the electrochromic element 100, the transmittance of the electrochromic element 100 changes as shown by curve 220; and in electrochromism After the element 100 is driven to change color, if the fading voltage is applied to the electrochromic element 100, the transmittance of the electrochromic element 100 changes as shown by the curve 230. As can be seen from Fig. 2, after the electrochromic element 100 is driven to change color, the fading speed (i.e., curve 220) is superior to other conditions when a suitable fading voltage is applied to the electrochromic element 100. It is worth noting that after the electrochromic element 100 is driven to change color, if the fading voltage is applied to the electrochromic element 100, its fading speed (i.e., curve 230) is the slowest.

3 is a graph showing the voltage applied to an electrochromic element and the transmittance of the electrochromic element as a function of time in one embodiment of the present application. Referring to FIG. 3, the voltage applied to the electrochromic element 100 and the transmittance of the electrochromic element 100 may change with time. As shown in FIG. 3, the driving process of the electrochromic element 100 may be divided into a first interval P1 between a time point t1 and a second time point t2, a second interval P2 between the second time point t2 and the third time point t3, and a third time point t3 and a fourth time point t4 The third interval between P3.

As shown in FIG. 3, in the first interval P1, the second interval P2, and the third interval P3, the voltage applied to the electrochromic element 100 changes as shown by the voltage curve 320, and when the applied voltage is different, The electrochromic element 100 exhibits different light transmittances, such as a light transmittance curve 310, in the first interval P1, the second interval P2, and the third interval P3, respectively. The voltage applied in the first interval P1 is the sensing voltage of the electrochromic element 100, and the voltage polarity thereof is opposite to the driving voltage applied in the second interval P2 and is in an increment/decrease state (see the second interval P2). Depending on the polarity of the applied voltage). The voltage applied in the second interval P2 is the driving voltage of the electrochromic element 100 for driving the electrochromic element 100 to change color, thereby causing the transmittance curve 310 of the electrochromic element 100 to decrease in the second interval P2. . The fading voltage applied in the third interval P3 is opposite to the driving voltage for discoloring the electrochromic element 100, thereby causing the transmittance curve 310 of the electrochromic element 100 in the third interval P3 to gradually increase ( Restore light transmittance). It is worth noting that the application time of the fade voltage may be shorter than or equal to the third interval P3.

In an embodiment of the present application, a sensing voltage that is opposite to the driving voltage is applied to the electrochromic element 100 in the first interval P1 before the second interval P2. This sense voltage, which is opposite to the drive voltage, is, for example, incremented or decremented with time from 0 until the corresponding light transmittance curve 310 of the electrochromic element 100 begins to drop. That is, when the driving voltage is a negative value, the sensing voltage starts to increase with time from 0, and when the driving voltage is positive, the sensing voltage starts to decrease with time from 0. In other words, the aforementioned sensing voltage fluctuates within a voltage range, and the voltage range is a maximum voltage value applied from 0V to P2, and the variation of the sensing voltage can be represented by a waveform, which is used to represent the sensing voltage change. The waveform is, for example, a triangular waveform or a staircase waveform having a specific slope, but the present application is not limited thereto. For example, the voltage value obtained at the second time point t2 can be defined as a threshold voltage value, and the fade voltage applied to the electrochromic element 100 in the third interval P3 is determined by the threshold voltage value. It should be noted that the foregoing threshold voltage value is not limited to the voltage value corresponding to the second time point t2, and the foregoing threshold voltage value may be the corresponding voltage value at a specific time in the first interval P1. The corresponding conditions will vary depending on the electrochromic material and the electrolyte material system.

In addition to detecting the light transmittance of the electrochromic element 100, the sensing method of the threshold voltage value can also be determined by the change in current or voltage of the electrochromic element 100. In other words, the aforementioned sensing method of the threshold voltage value can be determined by a change in one of the light transmittance, current, and voltage of the electrochromic element 100. On the other hand, in the first interval P1, the electrochromic element 100 starts to change color depending on the decrease in transmittance thereof, and those skilled in the art can preset a relative decrease in the relative light transmittance to judge the electrochromic element. Whether 100 starts to change color. For example, the discoloration depends on the aforementioned decrease in the relative light transmittance, for example, setting the original light transmittance to 100%, and when the light transmittance is reduced to 90% of the original light transmittance or other threshold value, Can be considered to start discoloration.

In an embodiment of the present application, the threshold voltage value is a negative value, and the corresponding sensing voltage and the fading voltage are negative voltages, and the driving voltage is a positive voltage. In another embodiment of the present application, the threshold voltage value is a positive value, the corresponding sensing voltage and the fading voltage are positive voltages, and the driving voltage is a negative voltage. In other words, the sensing voltage applied to the electrochromic element 100 is the same as the polarity of the fading voltage, and the sensing voltage applied to the electrochromic element 100 is opposite to the polarity of the driving voltage.

In this embodiment, the threshold voltage value is determined by the change of at least one of the light transmittance, the current, and the voltage of the electrochromic element 100. After determining the threshold voltage value, the threshold voltage value may be further determined. The fade voltage to be applied to the electrochromic element 100 in the third interval P3. In other words, there is a specific relationship between the fade voltage and the threshold voltage value. In one embodiment of the present application, the fade voltage is a threshold voltage value multiplied by a positive number less than or equal to one. For example, the aforementioned positive number is, for example, 0.8.

The correspondence between the threshold voltage value and the fade voltage applied to the electrochromic element 100 can be recorded in the control circuit of the electrochromic element 100 in a manner of a look-up table (LUT). For example, the aforementioned lookup table can be stored in the memory of the electrochromic element 100 in a firmware manner. Further, the correspondence between the threshold voltage value and the fade voltage applied to the electrochromic element 100 can be updated at any time depending on the aging of the electrochromic element 100 itself. Accordingly, the present embodiment can quickly determine the correct fade voltage of the electrochromic element 100, and the fade voltage can be appropriately adjusted and updated as the electrochromic element 100 itself ages.

In an embodiment of the present application, the electrochromic element 100 is continuously driven by the driving voltage a plurality of times, and the sensing voltage can be applied before each application of the driving voltage (second interval P2) (first interval) P1) is in the electrochromic element 100. In other words, there is a first interval P1 before each second interval P2 as shown in FIG. 6A. In other embodiments of the present application, the electrochromic element 100 is continuously driven by the driving voltage a plurality of times, and the application frequency of the sensing voltage (ie, the frequency of occurrence of the first interval P1) may be lower than the application frequency of the driving voltage. (that is, the frequency of occurrence of the second interval P2), thereby achieving the effect of saving power. In other words, there are a plurality of second intervals P2 between every two first intervals P1 as shown in FIG. 6B.

4A and 4B are schematic views showing an electrochromic element applied to a display panel in an embodiment of the present application. As shown in FIG. 4A, the electrochromic panel 400 includes a plurality of pixel structures 410, a plurality of sensing elements 420, a gate driving circuit 430, a source driving circuit 440, a driving electrode TX, and a sensing electrode RX. In FIG. 4A, each pixel structure 410 includes an electrochromic material and a pair of electrodes for driving the electrochromic material, and each of the sensing elements 420 corresponds to one of the pixel structures 410 for measurement. The light transmittance of the pixel structure 410. In addition, each pixel structure 410 is electrically connected to the gate driving circuit 430 and the source driving circuit 440 through corresponding scanning lines and data lines, and each sensing element 420 and the corresponding driving electrode TX and sense The measuring electrode RX is electrically connected. In other words, each pixel structure 410 will correspond to one sensing element 420, but the embodiment is not limited thereto. For example, not all of the pixel structure 410 transmittance must be measured by the sensing element 420. In other feasible embodiments, the number of sensing elements 420 may be less than the number of pixel structures 410. As shown in Figure 4B. In other words, the sensing element 420 performs a measurement of transmittance for only a portion of the pixel structure 410.

FIG. 5 is a flow chart showing the steps of a method for driving an electrochromic element according to an embodiment of the present application. Referring to FIG. 1A, FIG. 4A, FIG. 4B and FIG. 5, the electrochromic element driving method (shown in FIG. 5) of the present embodiment is applicable to at least the electrochromic element in FIG. 1A, FIG. 4A and FIG. 4B. 100. Electrochromic panel 400. Taking the electrochromic element 100 of FIG. 1A as an example, in step S500, the sensing voltage V _{1 that} varies within the voltage interval is applied to the electrochromic element 100. In step S510, a change in at least one of the light transmittance, the current, and the voltage of the electrochromic element 100 is measured to determine whether or not to start discoloration. In step S510, if the electrochromic device 100 does not begin to turn, perform step S520, the increment or decrement the sensing voltage V ₁ is with time. In step S510, if the electrochromic element 100 starts to change color, step S530 is performed to sense the threshold voltage value corresponding to the electrochromic element 100 starting to change color, and the threshold voltage value falls within the voltage range. And the threshold voltage value is multiplied by a positive number less than or equal to 1 to obtain a fade voltage V ₃ . In step S540, the driving voltage V _{2 is} applied to the electrochromic element 100 to discolor the electrochromic element. In step S550, the voltage V ₃ is applied to the bleaching of the electrochromic element 100 to accelerate the electrochromic element of electrochromic fading. In step S560, a change in at least one of the light transmittance, the current, and the voltage of the electrochromic element 100 is measured to determine whether the electrochromic element 100 has completed fading. In step S560, if the electrochromic element 100 has not completed fading, step S550 is repeatedly performed as described above. In step S560, if the electrochromic element 100 has been completed faded, step S570, stops the application of voltage fade V _3. It should be noted that, in other feasible embodiments, step S570 may also perform step S570 before the electrochromic element 100 has not completed fading, in other words, the application of the fading voltage V may be stopped before the electrochromic element 100 has completed fading. ₃ . In view of the above, regardless of the length of application of the fading voltage V ₃ , the effect of accelerating the fading of the electrochromic element can be achieved.

In summary, the above embodiment of the present application can determine the fading voltage required for the electrochromic element by sensing the voltage application, thereby reducing the time required for the electrochromic element to fade.

Although the present application has been disclosed in the above embodiments, it is not intended to limit the present application, and those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this application is subject to the definition of the scope of the patent application attached.

100‧‧‧Electrochromic components
400‧‧‧Electrochromic panel
110‧‧‧First substrate
120‧‧‧Second substrate
130‧‧‧First electrode layer
140‧‧‧Second electrode layer
150‧‧‧ electrolyte layer
160‧‧‧Electrochromic materials
210, 220, 230‧‧‧ curves
310‧‧‧Transmission curve
320‧‧‧ voltage curve
410‧‧‧ pixel structure
420‧‧‧Sensor components
430‧‧ ‧ gate drive circuit
440‧‧‧Source drive circuit
V‧‧‧ voltage
P1‧‧‧ first cycle
P2‧‧‧ second cycle
P3‧‧‧ third cycle
T1, t2, t3, t4‧‧‧ time
TX‧‧‧ drive electrode
RX‧‧‧Induction electrode

1A to 1C are respectively schematic cross-sectional views of the electrochromic element in an embodiment of the present application after being driven to change color, after being driven to change color, and after applying a fading voltage. 2 is a graph showing the transmittance of an electrochromic element as a function of time in one embodiment of the present application. Figure 3 is a graph showing the voltage applied to an electrochromic element and the transmittance of the electrochromic element as a function of time in one embodiment of the present application. 4A and 4B are schematic views of an electrochromic element applied to a display panel in an embodiment of the present application. FIG. 5 is a schematic flow chart of a driving method in an embodiment of the present application. 6A and 6B are schematic views respectively showing driving methods in different embodiments of the present application.

310‧‧‧Transmission curve

320‧‧‧ voltage curve

P1‧‧‧ first interval

P2‧‧‧Second interval

P3‧‧‧ third interval

T1‧‧‧ first time

T2‧‧‧ second time

T3‧‧‧ third time

T4‧‧‧fourth time

Claims (18)

A driving method for driving an electrochromic element, the electrochromic element driving method comprising: applying a sensing voltage that varies within a voltage interval to the electrochromic element to sense the electrochromic element a threshold voltage corresponding to the start of color change, and the threshold voltage value falls within the voltage range; determining a fade voltage according to the threshold voltage value; after sensing the threshold voltage value, applying a Driving a voltage to the electrochromic element to discolor the electrochromic element; and applying the fade voltage to the electrochromic element to accelerate fading of the electrochromic element. The driving method of claim 1, wherein the electrochromic element comprises a bipolar electrochromic element. The driving method of claim 1, wherein the electrochromic element comprises: a first electrode layer; a second electrode layer; an electrochromic material; and an electrolyte layer, wherein the electrochromic material And the electrolyte layer is located between the first electrode layer and the second electrode layer. The driving method of claim 3, wherein the electrolyte layer comprises an electrochromic electrolyte. The driving method of claim 1, wherein the sensing voltage is the same as the polarity of the fading voltage, and the sensing voltage is opposite to the polarity of the driving voltage. The driving method of claim 5, wherein the threshold voltage is a negative value, and the sensing voltage and the fading voltage are negative voltages, and the driving voltage is a positive voltage. The driving method of claim 5, wherein the threshold voltage is a positive value, and the sensing voltage and the fading voltage are positive voltages, and the driving voltage is a negative voltage. The driving method of claim 1, wherein the sensing method of the threshold voltage value comprises: measuring a change in at least one of a light transmittance, a current, and a voltage of the electrochromic element, Determine the threshold voltage value. The driving method of claim 1, wherein the sensing voltage is increased or decreased with time. The driving method of claim 1, wherein the sensing voltage is applied at a frequency lower than or equal to the driving voltage application frequency. The driving method of claim 1, wherein the method for determining the fade voltage according to the threshold voltage value comprises: multiplying the threshold voltage value by a positive number less than or equal to 1 to obtain the fade voltage . A method for determining a fade voltage suitable for determining a fade voltage of a discolored electrochromic element, the method comprising: applying a sense voltage that varies within a voltage interval to the electrochromic element to sense a threshold voltage value corresponding to the electrochromic element starting to change color, and the threshold voltage value falls within the voltage interval; and determining the fade voltage according to the threshold voltage value. The method of claim 12, wherein the sensing voltage is the same as the polarity of the fading voltage. The method of claim 13, wherein the threshold voltage is a negative value, and the sensing voltage and the fade voltage are negative voltages. The method of claim 13, wherein the threshold voltage is a positive value, and the sensing voltage and the fade voltage are positive voltages. The method of claim 12, wherein the sensing method of the threshold voltage value comprises: measuring a change in at least one of a light transmittance, a current, and a voltage of the electrochromic element to determine The threshold voltage value is obtained. The method of claim 12, wherein the sensing voltage is increasing or decreasing with time. The method of claim 12, wherein the method for determining the fade voltage according to the threshold voltage value comprises: multiplying the threshold voltage value by a positive number less than or equal to 1 to obtain the fade voltage .