Control method of display apparatus and display apparatus

Abstract

The control method of the display device (10) is a control method of a display device provided with a light control sheet (40) capable of switching between a transparent state and an opaque state, and in a case where an operation to turn on the display device (10) is obtained ("Yes" in S101), a PWM waveform based on a direct-current voltage generating an alternating-current voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% is output (S102), an alternating-current voltage is generated from the direct-current voltage based on the output PWM waveform (S103), and the generated alternating-current voltage is output to the light control sheet (40) (S104).

Description

Technical Field

[0001] This invention relates to a control method for a display device and a display device. Background Technology

[0002] Previously, dimming sheets containing a liquid crystal layer sandwiched between a pair of transparent electrode substrates were known (see Patent Document 1). Such dimming sheets are configured to switch between a transparent state and an opaque state (e.g., a cloudy state) by switching an alternating voltage applied between the transparent electrodes on and off.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-229946 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The AC voltage applied to the dimming disc is supplied, for example, from an industrial power source. In this case, since the phase of the AC voltage at the start of the dimming disc's operation cannot be controlled, an inrush current corresponding to the phase of the AC voltage is generated when the dimming disc starts operating, and this inrush current flows through the dimming disc. If such inrush currents are repeatedly generated, the electrodes of the dimming disc may be damaged, and the display state switching will no longer be able to be performed normally.

[0008] Therefore, the object of the present invention is to provide a control method for a display device capable of suppressing inrush current in a dimming disc, and a display device thereof.

[0009] Methods used to solve problems

[0010] To achieve the above objectives, a control method for a display device according to one technical solution of the present invention is a control method for a display device equipped with a dimming disc capable of switching between a transparent state and an opaque state. When a first operation of turning on the display device is achieved, a PWM waveform of an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% is generated based on a DC voltage. Based on the output PWM waveform, the AC voltage is generated from the DC voltage, and the generated AC voltage is output to the dimming disc.

[0011] To achieve the above objectives, one aspect of the present invention provides a display device equipped with a dimming disc capable of switching between a transparent state and an opaque state. The device comprises: a microcomputer that, upon receiving an operation to turn on the display device, outputs a PWM waveform of an AC voltage generated based on a DC voltage at a phase of 0 degrees or 180 degrees and a load factor of 50%; and a drive circuit that generates the AC voltage from the DC voltage based on the output PWM waveform and outputs the generated AC voltage to the dimming disc.

[0012] Invention Effects

[0013] According to a control method for a display device based on a technical solution of the present invention, inrush current in a dimming disc can be suppressed. Attached Figure Description

[0014] Figure 1 This is a diagram showing the cross-sectional structure of the dimmer in the comparative example.

[0015] Figure 2 This is a diagram showing the situation where gaps were generated in the dimmer sheet of the comparative example.

[0016] Figure 3 This is a perspective view showing the appearance of the display device according to the embodiment.

[0017] Figure 4 This is a perspective view showing the structure of the display device according to the embodiment.

[0018] Figure 5 This is a block diagram illustrating the functional structure of the display device in the implementation method.

[0019] Figure 6 This is a diagram showing the electrode structure of the dimming disc in the embodiment.

[0020] Figure 7 This is a graph showing the relationship between the electrode width and current density of the dimming disc in the embodiment.

[0021] Figure 8 This is a circuit diagram showing the second power supply circuit in the implementation method.

[0022] Figure 9 It is a diagram showing the waveform of the AC voltage supplied to the dimming disc in the embodiment.

[0023] Figure 10 This is a flowchart illustrating the actions of turning on the display device in the implementation method.

[0024] Figure 11 This is a flowchart illustrating the actions taken when the display device of the implementation method is turned off. Detailed Implementation

[0025] (The process of achieving this invention)

[0026] Before describing the embodiments of the present invention, the understanding that forms the basis of the present invention will be explained. Figure 1 This is a diagram showing the cross-sectional structure of the dimmer plate 140 of the comparative example. Additionally, in Figure 1 The shading in the illustration is omitted.

[0027] like Figure 1 As shown, the dimming plate 140 has substrates 41 and 43, and ITO (Indium Tin Oxide) films 44 and 45 disposed on opposite surfaces of substrates 41 and 43. Figure 1 ITO in the film), and light adjustment layer 42 disposed inside the ITO films 44 and 45. Figure 1 The dimming disc 140 is an SPD (Suspended Particle Device) in the diagram. It controls the transmittance of incident light. Since the dimming disc 140 only needs to control the transmittance of incident light, it can also be called a light-blocking shutter, a transmission shutter, or a light attenuation device. Furthermore, the dimming disc 140 can be used, for example, overlaid with a light-transmitting display. A light-transmitting display is, for example, a transparent OLED (Organic Light Emitting Diode) panel. Hereinafter, the description assumes that a transparent display is overlaid on the substrate 41 side of the dimming disc 140, but the arrangement of the dimming disc 140 and the transparent display is not limited to this.

[0028] Substrates 41 and 43 are made of a light-transmitting material. Substrates 41 and 43 are, for example, PET (Polyethlene Terephthalate) films, but can also be glass substrates or acrylic substrates, etc.

[0029] The light-adjusting layer 42 is formed by dispersing a light-adjusting suspension in the resin. The light-adjusting suspension contains light-adjusting particles that respond to an electric field. The dimming plate 140 adjusts the light transmittance by utilizing the polarization orientation of the light-adjusting particles, as detailed later.

[0030] ITO films 44 and 45 form the capacitors of the dimming sheet 140. ITO films 44 and 45 are made of a transparent electrode material, such as a metal oxide like ITO. ITO films 44 and 45 are electrically connected to an industrial power supply. In the comparative example dimming sheet 140, a conductive strip (e.g., a Cu foil strip) used to supply AC voltage to the dimming sheet 140 and the ITO film 45 are bonded together with a conductive paste 46 (e.g., silver paste). The portion where the ITO film 45 and the conductive strip are bonded together via the conductive paste 46, and its periphery, are also referred to as the electrode portion. The electrode portion is the portion of the dimming sheet 140 that is not used for display. Furthermore, in Figure 1The conductive band in the middle is omitted from the diagram (see reference). Figure 6 (The conductive band is 90). Furthermore, conductive paste 46 is an example of an electrode.

[0031] ITO films 44 and 45 are examples of transparent electrodes. However, transparent electrodes are not limited to ITO films 44 and 45; any conductive layer that is transparent is not particularly limited.

[0032] The sealing tape 47 is a protective tape that covers the electrode portion of the dimming disc 140. The sealing tape 47 is installed, for example, in a manner that covers a portion of the substrate 41 and the electrode portion.

[0033] Next, the two display states of the dimming disc 140—an opaque state and a transparent state—will be described. Furthermore, examples of transitions between the two display states will be described below with respect to the dimming disc 140, but this is not a limitation. For example, it is also possible for at least one of the opaque and transparent states to have multiple states with different transmittances.

[0034] In the dimming disc 140, if an electric field is generated in the light adjustment layer 42 by applying a voltage between the ITO films 44 and 45, the light adjustment particles become polarized and align in a direction parallel to the electric field, so incident light is transmitted through the light adjustment layer 42. That is, the dimming disc 140 becomes transparent when a voltage is applied, allowing incident light to pass through. It can also be said that the dimming disc 140 becomes a high-transmittance state with high transmittance. In this state, if one side of the dimming disc 140 (e.g., the substrate 41 side) is viewed from the other side of the dimming disc 140 (e.g., the substrate 43 side), an object (e.g., a display item) disposed on the other side of the dimming disc 140 can be seen.

[0035] Furthermore, when no voltage is applied between the ITO films 44 and 45, and thus no electric field is generated in the light adjustment layer 42, the incident light is blocked by the light adjustment layer 42 because the light adjustment particles dispersed in the light adjustment suspension absorb, scatter, or reflect light through Brownian motion. In other words, if no voltage is applied, the dimming sheet 140 becomes opaque, making it difficult for incident light to pass through compared to a transparent state. Alternatively, the dimming sheet 140 can be described as a low-transmittance state, with a lower transmittance than a high-transmittance state. In this state, even when viewing the other side (e.g., the substrate 43 side) of the dimming sheet 140 from one side (e.g., the substrate 41 side), objects disposed on the other side of the dimming sheet 140 cannot be seen. In this state, by displaying the image on a transparent display, the user can view the image on the transparent display.

[0036] In addition, the opaque state can be any state where the transmittance is lower than that of the transparent state.

[0037] The dimming strip 140 described above is transparent when supplied with AC voltage and opaque when not supplied with AC voltage from the industrial power source. However, when switching between the presence and absence of AC voltage from the industrial power source, since the phase of the AC voltage supply cannot be controlled, a large current may be generated, resulting in a current exceeding the allowable current value of the dimming strip 140. For example, since the ITO films 44 and 45 constituting the dimming strip 140 form capacitors, if they are turned on at a phase of 90 degrees or 270 degrees (at maximum voltage), the inrush current flowing through the capacitors increases. As a result, the drive circuit or electrode material of the dimming strip 140 deteriorates, leading to decreased reliability and potential malfunctions. Figure 2 This diagram shows the situation where gap B was generated in the dimmer 140 of the comparative example.

[0038] like Figure 2 As shown, a void B is generated between the ITO film 45 and the conductive paste 46. It is presumed that void B is generated by the heat produced by the surge current. Furthermore, under the action of this heat, void B sparks, resulting in spark damage and destruction of the electrode portion.

[0039] Therefore, regarding display devices equipped with a dimming disc, the inventors of this invention have carefully studied control methods for display devices that can suppress inrush currents in the dimming disc when switching between the presence and absence of power supply to the dimming disc, and have devised the control method for the display device described below.

[0040] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the embodiments described below are general or specific examples. The numerical values, shapes, materials, constituent elements, arrangement and connection methods of constituent elements, steps, and order of steps shown in the following embodiments are examples and are not intended to limit the present invention. In addition, any constituent elements in the following embodiments that are not described in the independent claims will be described as arbitrary constituent elements.

[0041] Furthermore, the figures are schematic diagrams and not necessarily strictly representational. Also, in the figures, substantially identical structures are assigned the same labels, and there are instances where repeated explanations have been omitted or simplified.

[0042] Furthermore, in this specification, terms such as "equal" and numerical values ​​that indicate the relationship between elements do not merely represent a strict meaning, but rather imply that they represent substantially the same range, for example, including differences of a few percentage points.

[0043] (Implementation Method)

[0044] The following is for reference Figures 3 to 11The display device 10 of this embodiment will be described.

[0045] [1. Structure of the display device]

[0046] First, refer to Figures 3-9 The structure of the display device 10 in this embodiment will be described.

[0047] Figure 3 This is a perspective view showing the appearance of the display device 10 according to this embodiment. Figure 4 This is a perspective view showing the structure of the display device 10 according to this embodiment. Figure 4 It is Figure 3 The figure shown is an enlarged representation of the dashed area R with the box 50 omitted. Figure 5 This is a block diagram illustrating the functional structure of the display device 10 in this embodiment.

[0048] like Figures 3-5 As shown, the display device 10 includes a reinforcing plate 20, a display panel 30, a dimming disc 40, a frame 50, an operation acquisition unit 60, a first power supply circuit 70, and a second power supply circuit 80. The display device 10 is constructed by sequentially bonding the reinforcing plate 20, the display panel 30, and the dimming disc 40 together. The reinforcing plate 20 side is the front side, allowing the user to view the display device 10 from, for example, the reinforcing plate 20 side. Furthermore, the display panel 30 side is the back side, allowing the user to see an object (e.g., a display item) placed on the back of the display panel 30 when the dimming disc 40 is transparent. Additionally, the bonding of each structure is achieved, for example, using a highly transparent adhesive component such as OCA (Optical Clear Adhesive).

[0049] The reinforcing plate 20 is disposed on the front side of the display panel 30 and serves as a cover component that covers the display panel 30 and the like. The reinforcing plate 20 is made of a light-transmitting material, such as reinforced glass. Furthermore, the reinforcing plate 20 is not a necessary structure; for example, it can be a structure that is bent and supports the display panel 30 and the like through its tension.

[0050] The display panel 30 is a light-transmitting display, such as a transparent OLED panel. The display panel 30 operates by receiving a voltage supply from the first power supply circuit 70. The display panel 30 displays information when the dimming disc 40 is in an opaque state.

[0051] The dimming disc 40 is disposed on the back side of the display panel 30 and is a disc component capable of switching between a transparent state and an opaque state. For example, the dimming disc 40 becomes transparent when an AC voltage is supplied and becomes opaque when no AC voltage is supplied. The structure of the dimming disc 40 can be the same as that of the dimming disc 140 in the comparative example, and the description is omitted.

[0052] Furthermore, while the above description illustrates an example of a dimmer sheet 40 that adjusts light transmittance using an SPD method, it is not limited to this. The dimmer sheet 40 can be light-transmitting and configured to adjust its transmittance by the presence or absence of an applied alternating voltage (e.g., the presence or absence of an electric field). The dimmer sheet 40 can also be a dimmer sheet that adjusts light transmittance using an EC (Electro Chromic) method or a dimmer sheet that adjusts light transmittance using a PDLC (Polymer Dispersed Liquid Crystal) method.

[0053] Furthermore, the dimming plate 40 in this embodiment does not receive AC voltage directly from the industrial power supply P1, as will be described in detail later.

[0054] Here, refer to Figure 6 and Figure 7 The structure of the electrode section of the dimming plate 40 will be explained. Figure 6 This is a diagram showing the structure of the electrode portion of the dimming disc 40 in this embodiment.

[0055] like Figure 6 As shown, an ITO film 45 is formed on the surface of the substrate 43, and a conductive paste 46 is coated on the ITO film 45. The conductive paste 46 is, for example, silver paste, applied by printing or the like. A conductive strip 90 for electrically connecting the ITO film 45 to the second power supply circuit 80 is connected to the conductive paste 46.

[0056] One of the two conductive pastes 46 is electrically connected to the ITO film 45, and the other of the two conductive pastes 46 is electrically connected to the ITO film 44 of the substrate 41. Thus, the dimming disc 40 constitutes a capacitor. Alternatively, the other of the two conductive pastes 46 may be formed on the substrate 41.

[0057] Here, refer to Figure 7 The width of conductive paste 46 ( Figure 6 The electrode width W in the figure is explained. Figure 7 This is a graph showing the relationship between the electrode width W of the dimming plate 40 in this embodiment and the current density.

[0058] like Figure 7 As shown, the current density in the conductive paste 46 is preferably 500 mA / mm². 2 The following (refer to) Figure 7 (The design target area). That is, the maximum current density of the impact current is preferably 500 mA / mm². 2 The following is an example of setting the current density to 500 mA / mm². 2 Therefore, even when an inrush current of 200mA flows, damage to the electrode portion of the dimming disc 40 can be suppressed.

[0059] The current density is 1333 mA / mm when the impulse current is 200 mA and the electrode width W is 150 mm. 2 Furthermore, the current density is 434 mA / mm when the impulse current is 200 mA and the electrode width W is 460 mm. 2 The inrush current becomes 500mA / mm. 2 The electrode width W is 400 mm. In other words, the electrode width W is preferably 400 mm or more. The electrode width W can be 460 mm.

[0060] Furthermore, the electrode width W is not limited to 400 mm or more. The electrode width W can be any width that ensures the reliable connection between the ITO film 45 and the conductive paste 46, for example, it can also be 150 mm.

[0061] Refer again Figure 3 The frame portion 50 is a frame that surrounds the sides of the display device 10. That is, the frame portion 50 surrounds the display device 10 except for the front and back sides. As a result, when the dimming disc 40 is in a transparent state, the display device 10 allows the user to see objects (e.g., displays) arranged on the back side of the display device 10.

[0062] Refer again Figure 5 The operation acquisition unit 60 acquires user operations on the display device 10. The operation acquisition unit 60 can, for example, acquire signals corresponding to the user's operation from a portable terminal such as a smartphone or a dedicated remote control via communication. In this case, the operation acquisition unit 60 is configured to include a communication circuit. Alternatively, the operation acquisition unit 60 can be a button or the like provided on the display device 10. Furthermore, the operation acquisition unit 60 can acquire user operations based on voice or gesture. In this case, the operation acquisition unit 60 can be configured to include a communication circuit, or it can include a microphone or a camera. Hereinafter, we will assume that the operation acquisition unit 60 acquires user operations via communication.

[0063] The first power supply circuit 70 supplies power to the display panel 30 for operation. The first power supply circuit 70 is connected to the industrial power supply P1 and the display panel 30, converting the AC voltage from the industrial power supply P1 into a desired DC voltage and supplying it to the display panel 30. Alternatively, the first power supply circuit 70 can be described as supplying power to the display panel 30 based on the power from the industrial power supply P1. The first power supply circuit 70 begins supplying DC voltage to the display panel 30 when the operation acquisition unit 60 receives a signal to start the display of the display device 10, and stops supplying DC voltage to the display panel 30 when the operation acquisition unit 60 receives a signal to stop the display of the display device 10.

[0064] Furthermore, the first power supply circuit 70 does not supply power to the dimming disc 40. Thus, the display device 10 has a structure that does not directly supply power from the industrial power supply P1 to the dimming disc 40.

[0065] The first power supply circuit 70 is configured to include an A / D converter that converts AC voltage into a desired DC voltage and a control device that controls the operation of the A / D converter.

[0066] The second power supply circuit 80 supplies power to the dimming disc 40 for operation. The second power supply circuit 80 is connected to the dimming disc 40 and converts DC voltage into a desired AC voltage, supplying it to the dimming disc 40. The second power supply circuit 80 can also be described as supplying power to the dimming disc 40 from a power source different from the industrial power supply P1. The second power supply circuit 80 begins supplying AC voltage to the dimming disc 40 when the operation acquisition unit 60 receives a signal to start the display of the display device 10, and stops supplying AC power to the dimming disc 40 when the operation acquisition unit 60 receives a signal to stop the display of the display device 10.

[0067] Here, further reference Figure 8 The second power supply circuit 80 will be described. Figure 8 This is a circuit diagram showing the second power supply circuit 80 of this embodiment. Additionally, Figure 8 The circuit diagram shown is an example and is not limited to this.

[0068] like Figure 8 As shown, the second power supply circuit 80 includes a microcomputer 81, a drive circuit 82, a DC power supply P2, transistors Q1 to Q4, and a low-pass filter (e.g., an inductor L and a capacitor C).

[0069] The microcomputer 81 controls the output of the AC voltage to the dimming disc 40. When the operation acquisition unit 60 obtains a signal to start the display of the display device 10, the microcomputer 81 outputs a PWM waveform to the drive circuit 82 to generate an AC waveform with a phase of 0 degrees or 180 degrees and a duty rate of 50% based on the DC voltage supplied from the DC power supply P2. The voltage value of the AC voltage generated based on this PWM waveform at a phase of 0 degrees or 180 degrees is zero volts (0V). Furthermore, zero volts includes not only completely zero volts but also voltages that can be substantially considered zero volts. Zero volts, for example, includes a voltage of less than 5% of the maximum AC voltage supplied to the dimming disc 40. Furthermore, a phase of 0 degrees or 180 degrees includes not only completely 0 degrees or 180 degrees but also voltages that can be substantially considered 0 degrees or 180 degrees. For example, it includes a phase deviation corresponding to a voltage of less than 5% of the maximum AC voltage supplied to the dimming disc 40.

[0070] In this embodiment, the PWM waveform is generated by a microcomputer 81 with a built-in timer circuit. For the microcomputer 81, the input is a digital signal obtained by converting an analog waveform (e.g., a sine wave) of the AC voltage to be used as the target voltage using an A / D converter. The timer circuit generates the PWM signal based on this digital signal. The PWM signal is, for example, pre-generated and stored in a storage unit (not shown). The microcomputer 81 is an example of a digital circuit. Furthermore, the digital circuit is an example of a PWM waveform output unit.

[0071] By generating the PWM waveform using digital circuitry, the phase (0 degrees or 180 degrees) of the AC voltage supplied to the dimming disc 40 when it is turned on can be controlled with greater precision compared to generating the PWM waveform using analog circuitry. Furthermore, the digital circuitry is not limited to the microcomputer 81; it can also be implemented, for example, by an FPGA (Field Programmable Gate Array) with built-in timer circuitry. The FPGA can be programmed after LSI manufacturing.

[0072] The drive circuit 82 controls the on / off state of transistors Q1 to Q4 based on the PWM waveform from the microcomputer 81. During the positive half-cycle of the PWM waveform from the microcomputer 81, the drive circuit 82 simultaneously turns on transistors Q1 and Q4, causing the DC voltage (hereinafter also denoted as DC voltage E) of the DC power supply P2 to be output. Furthermore, during the negative half-cycle of the PWM waveform from the microcomputer 81, the drive circuit 82 simultaneously turns on transistors Q2 and Q3, causing the DC voltage -E to be output. The output voltage Vout1 becomes a pulse train composed of the DC voltages E and -E.

[0073] The driving circuit 82 is implemented, for example, by the following circuits: a logic circuit based on a PWM waveform, outputting one of a first signal for simultaneously turning on transistors Q1 and Q4 and a second signal for simultaneously turning on transistors Q2 and Q3; a first driving circuit that turns on transistors Q1 and Q4 when the first signal is output; and a second driving circuit that turns on transistors Q2 and Q3 when the second signal is output.

[0074] DC power supply P2 is used to supply AC voltage to the dimmer 40. The DC voltage E of DC power supply P2 is, for example, 350V, but it is not limited to this, as long as it is a voltage that can switch the dimmer 40 on and off.

[0075] The second power supply circuit 80 has a DC power supply P2, which enables the supply of an AC voltage of any value to the dimming switch 40. The AC voltage supplied to the dimming switch 40 varies depending on the specifications of the dimming switch 40. Therefore, since the second power supply circuit 80 has a DC power supply P2, it can supply an AC voltage corresponding to the specifications of the dimming switch 40 regardless of its specifications. Furthermore, the DC power supply P2 is, for example, a power supply independent of the industrial power supply P1. That is, the DC power supply P2 is not electrically connected to the industrial power supply P1, for example.

[0076] In this way, the dimming sheet 40 can be controlled to one or more intermediate states between a transparent state and an opaque state. The dimming sheet 40 can also be said to be able to switch between one or more intermediate states between a transparent state and an opaque state. An intermediate state is a state of transmittance between the transmittance of the dimming sheet 40 when it is in the transparent state and the transmittance when it is in the opaque state. For example, the dimming sheet 40 can be controlled to any transmittance by receiving an AC voltage of any value from the second power supply circuit 80.

[0077] In addition, the display panel 30 displays an image when there is one or more intermediate states, but it is not limited to this. It is also possible not to display an image when there is at least one intermediate state among the one or more intermediate states.

[0078] Alternatively, the industrial power supply P1 (AC) can be converted to DC voltage, and an AC voltage supplied to the dimming disc 40 can be generated from the converted DC voltage using a PWM waveform. However, in this case, since the DC voltage value depends on the voltage value of the industrial power supply P1, a transformer or the like is required to set a voltage value corresponding to the specifications of the dimming disc 40, resulting in a larger display device. In this embodiment, by using a DC power supply P2, the larger size of the display device 10 can be prevented, and the desired AC voltage can be supplied to the dimming disc 40.

[0079] The DC power supply P2 may be built into the display device 10, or it may be configured externally to the display device 10.

[0080] In addition, power from DC power supply P2 is not supplied to display panel 30, for example.

[0081] Transistors Q1 through Q4 are switching transistors that are controlled to be turned on or off by the drive circuit 82. Any known transistors can be used for Q1 through Q4.

[0082] A low-pass filter is provided to output a sinusoidal AC voltage with minimal distortion. In this embodiment, it is composed of an inductor L and a capacitor C. The second power supply circuit 80 obtains an output voltage Vout2 (AC voltage) with minimal distortion by passing the output voltage Vout1 through the low-pass filter. The output voltage Vout2 is then supplied to the dimming disc 40. Furthermore, the low-pass filter is not limited to being composed of an inductor L and a capacitor C; any known low-pass filter can be used as long as it reduces the distortion of the output voltage Vout2.

[0083] Thus, in this embodiment, the dimming disc 40 is not directly supplied with AC voltage from the industrial power supply P1. Instead, the dimming disc 40 is supplied with AC voltage whose phase is controlled when switching between the presence and absence of AC voltage supply.

[0084] in addition, Figure 8 The circuit structure shown is an example; any known circuit structure can be used as long as it can generate an AC voltage based on the PWM waveform output from the microcomputer 81 and the DC voltage from the DC power supply P2. Furthermore, in the second power supply circuit 80, an example of outputting the PWM waveform via a digital circuit is illustrated, but it is not limited to this. The PWM waveform can also be output via an analog circuit. For example, the PWM waveform can be the output of a comparator (voltage comparator) obtained by inputting an analog waveform (e.g., a sine wave) of the target AC voltage and a modulation wave (e.g., a sawtooth wave) into the comparator. An analog circuit is an example of a PWM waveform output section.

[0085] Here, refer to Figure 9 The output voltage Vout2 from the second power supply circuit 80 to the dimming plate 40 will be explained. Figure 9 This is a diagram showing the waveform (drive waveform) of the AC voltage supplied to the dimming disc 40 in this embodiment. Figure 9 The diagram shows the driving waveform input to the dimming disc 40 and the on / off timing of the display panel 30. Furthermore, assuming that at time t1, the operation acquisition unit 60 acquires an operation to turn on the display device 10, and at time t4, the operation acquisition unit 60 acquires an operation to turn off the display device 10. Additionally, Figure 9 The horizontal axis represents time, and the vertical axis represents voltage. Additionally, in... Figure 9 In this circuit, the drive waveform input to the dimming plate 40 is represented by a standardized voltage. Voltage "1" represents the maximum voltage on the positive side, and voltage "0" represents the maximum voltage on the negative side.

[0086] like Figure 9As shown, at time t1, when the operation acquisition unit 60 acquires the operation of turning on the display device 10, a DC voltage is supplied from the first power supply circuit 70 to the display panel 30. As a result, the display panel 30 can display images.

[0087] Next, at time t2, the supply of AC voltage from the second power supply circuit 80 to the dimming disc 40 begins, corresponding to the operation of turning on the display device 10 at time t1. As a result, the state of the dimming disc 40 changes from a transparent state to an opaque state.

[0088] Thus, the timing of the start of the voltage supply from the first power supply circuit 70 and the second power supply circuit 80 corresponding to the operation of turning on the display device 10 can be different. For example, the timing of the start of the AC voltage supply from the second power supply circuit 80 to the dimming disc 40 can be later than the timing of the start of the DC voltage supply from the first power supply circuit 70 to the display panel 30. In other words, the AC voltage supply to the dimming disc 40 can begin after the DC voltage supply to the display panel 30 has started corresponding to the operation of turning on the display device 10.

[0089] Furthermore, the interval between times t1 and t2 is, for example, approximately 0 to 20 ms, but is not limited to this. Additionally, times t2 to t3 represent one cycle of the drive waveform input to the dimming disc 40. One cycle is generated, for example, based on 1024 voltage data points (output voltage Vout1). Furthermore, times t2 and t3 are the moments when the phase of the drive waveform reaches 0 degrees. Moreover, the exact midpoint between times t2 and t3 is the moment when the phase of the drive waveform reaches 180 degrees. Figure 9 In this context, time t2 starts from phase 0 degrees, but it is not limited to this; it can also start from phase 180 degrees.

[0090] Here, at time t2, regarding the drive waveform input to the dimming strip 40, the drive waveform starts with a voltage of "0.5". This is an example of an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50%. Furthermore, a voltage of "0.5", i.e., a load rate of 50%, is zero volts. Thus, since the drive waveform starts from zero volts, the inrush current generated when the dimming strip 40 is turned on can be suppressed. When the PWM waveform is generated by the microcomputer 81, since the phase can be controlled with good precision at 0 degrees or 180 degrees, the inrush current can be further suppressed.

[0091] Next, at time t4, when the operation acquisition unit 60 obtains the operation to turn off the display device 10, the supply of DC voltage from the first power supply circuit 70 to the display panel 30 is stopped. As a result, the display panel 30 is turned off.

[0092] Next, at time t5, the supply of AC voltage from the second power circuit 80 to the dimming disc 40, corresponding to the operation of turning off the display device 10 obtained at time t4, is stopped. Thus, the timing of the cessation of the voltage supply from the first power circuit 70 and the second power circuit 80, corresponding to the operation of turning off the display device 10, can be different. For example, the timing of the cessation of the AC voltage supply from the second power circuit 80 to the dimming disc 40 can be later than the timing of the cessation of the DC voltage supply from the first power circuit 70 to the display panel 30. In other words, the supply of AC voltage to the dimming disc 40 can stop after the cessation of the DC voltage supply to the display panel 30 corresponding to the operation of turning off the display device 10.

[0093] The second power supply circuit 80, after time t4, stops supplying power to the dimming plate 40 when the driving waveform reaches zero volts. For example, the second power supply circuit 80 stops supplying power when the driving waveform initially reaches zero volts after time t4. Figure 9 At time t5, the power supply to the dimming strip 40 is stopped. This stops the power supply when the drive waveform is at zero volts, thus suppressing the discharge current generated when the dimming strip 40 is turned off. Since the PWM waveform is generated by the microcomputer 81, the phase can be controlled with good precision at 0 degrees or 180 degrees, further suppressing the discharge current. By suppressing the discharge current, the deterioration of the reliability of the dimming strip 40 can be further suppressed.

[0094] By supplying the AC voltage as described above each time the dimming switch 40 is turned on, the magnitude of the inrush current generated each time the dimming switch 40 is turned on can be kept approximately constant. On the other hand, if the AC voltage is supplied directly to the dimming switch 40 from the industrial power supply P1, phase control cannot be performed, so the magnitude of the inrush current generated each time the dimming switch 40 is turned on varies. For example, if the AC voltage is supplied to the dimming switch 40 at a phase of 90 degrees or 270 degrees (when the voltage is at its maximum), a larger inrush current is generated. Furthermore, for example, if the AC voltage is supplied to the dimming switch 40 at a phase of 0 degrees or 180 degrees (when the voltage is at its minimum), a smaller inrush current is generated. Thus, when the AC voltage is supplied directly to the dimming switch 40 from the industrial power supply P1, the magnitude of the inrush current generated each time the dimming switch 40 is turned on varies. Therefore, the timing of electrode damage varies depending on each display device.

[0095] In addition, Figure 9 In the process, the supply stops at 180 degrees phase at time t5, but it is not limited to this; it can also stop at 0 degrees phase.

[0096] Furthermore, it is not necessary for the dimming switch 40 to be turned off at a phase of 0 degrees or 180 degrees (i.e., at zero volts). The second power supply circuit 80 can, for example, stop supplying AC voltage to the dimming switch 40 at time t4.

[0097] [2. Operation of the display device]

[0098] Next, refer to Figure 10 and Figure 11 The operation of the display device 10 in this embodiment will be explained. First, refer to... Figure 10 The operation of turning on the display device 10 will be explained. Figure 10 This is a flowchart illustrating the operation when the display device 10 of this embodiment is turned on. Specifically, Figure 10 This is a flowchart showing the action when the dimming filter 40 is turned on.

[0099] like Figure 10 As shown, when the operation acquisition unit 60 acquires the operation of turning on the display device 10 ("Yes" in S101), the microcomputer 81 of the second power supply circuit 80 outputs a PWM waveform with a phase of 0 degrees and 180 degrees of AC voltage at a load rate of 50% (S102). That is, the microcomputer 81 outputs a PWM waveform that makes the load rate 50% when the phase of AC voltage is 0 degrees and 180 degrees. The microcomputer 81 can also be said to output a PWM waveform that makes the voltage at the phase of AC voltage 0 degrees and 180 degrees zero volts. The microcomputer 81 outputs the PWM waveform by reading the program generated in order to output such a PWM waveform from the storage unit (not shown). For example, the microcomputer 81 can start reading from the position of the PWM waveform stored in the storage unit where the phase of AC voltage supplied by the second power supply circuit 80 to the dimming plate 40 is 0 degrees and 180 degrees at a load rate of 50%. In this embodiment, the microcomputer 81 intentionally sets the position at which the PWM waveform reading begins to be set as described above.

[0100] Next, the drive circuit 82 controls the on / off state of transistors Q1 to Q4 to generate an AC voltage with phases of 0 degrees and 180 degrees, corresponding to a load factor of 50%, from the DC voltage E of the DC power supply P2 based on the PWM waveform from the microcomputer 81 (S103). This generates... Figure 9 The output voltage Vout1 is shown.

[0101] Next, the output voltage Vout1 generated in step S103 passes through the low-pass filter, thereby generating an output voltage Vout2 as an AC waveform with minimal distortion. This output voltage Vout2 is output as an AC voltage to the dimming plate 40 (S104). Thus, Figure 9The supply of AC voltage as shown to the dimming disc 40 begins.

[0102] In addition, the supply of DC voltage from the first power supply circuit 70 to the display panel 30 is performed, for example, between steps S101 and S103.

[0103] Furthermore, the microcomputer 81 of the second power supply circuit 80 does not output a PWM waveform when the operation acquisition unit 60 does not acquire the operation to turn on the display device 10 ("No" in S101). Therefore, the drive circuit 82 does not output a signal to turn on transistors Q1 to Q4, so transistors Q1 to Q4 are all in the off state. That is, AC voltage is not supplied from the second power supply circuit 80 to the dimming disc 40, so the dimming disc 40 remains in a transparent state.

[0104] Next, refer to Figure 11 The operation of turning off the display device 10 will be explained. Figure 11 This is a flowchart illustrating the operation when the display device 10 of this embodiment is turned off. Specifically, Figure 11 This is a flowchart showing the action when dimming switch 40 is turned off.

[0105] like Figure 11 As shown, when the operation acquisition unit 60 obtains the operation of turning off the display device 10 ("Yes" in S201), the microcomputer 81 of the second power supply circuit 80 determines whether the phase of the AC voltage at the current time point is 0 degrees or 180 degrees (S202). For example, the microcomputer 81 can perform the determination in step S202 based on the waveform of the PWM signal output at the current time point.

[0106] The microcomputer 81 stops the output of the PWM waveform when the phase of the AC voltage is 0 degrees or 180 degrees ("Yes" in S202) (S203). Thus, as... Figure 9 As shown, the supply of AC voltage to the dimming plate 40 stops when the phase of the AC voltage is 0 degrees or 180 degrees. Additionally, the cessation of the supply of DC voltage from the first power supply circuit 70 to the display panel 30 is performed, for example, between steps S201 and S203.

[0107] Furthermore, if the phase of the AC voltage is not 0 degrees or 180 degrees ("No" in S202), the microcomputer 81 continues to output the PWM waveform (S204). That is, the microcomputer 81 continues to output the PWM waveform until the phase of the AC voltage becomes 0 degrees or 180 degrees. Alternatively, the microcomputer 81 can be said to continue outputting the PWM waveform from the time point in step S201 until the time point when the AC voltage becomes zero volts. Thus, even if the operation acquisition unit 60 acquires the operation to turn off the display device 10, the microcomputer 81 will not stop the output of the PWM waveform until the phase of the AC voltage becomes 0 degrees or 180 degrees, that is, until the AC voltage becomes zero volts.

[0108] Furthermore, if the operation acquisition unit 60 does not obtain the operation to turn off the display device 10 ("No" in S201), the microcomputer 81 of the second power supply circuit 80 returns to step S201 and continues to output the PWM waveform until the operation to turn off the display device 10 is obtained. As a result, AC voltage is continuously supplied from the second power supply circuit 80 to the dimming disc 40, so the dimming disc 40 remains opaque.

[0109] In addition, the display device 10 is capable of performing Figure 10 and Figure 11 At least of the actions shown Figure 10 The actions shown are sufficient.

[0110] [3. Effects, etc.]

[0111] As described above, the control method of the display device 10 in this embodiment is a control method of the display device 10 equipped with a dimming disc 40 capable of switching between a transparent state and an opaque state. When the operation of turning on the display device 10 is obtained ("Yes" in S101), a PWM waveform of an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% is generated based on the DC voltage (S102). Based on the output PWM waveform, an AC voltage is generated from the DC voltage (S103), and the generated AC voltage is output to the dimming disc 40 (S104).

[0112] Therefore, an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% is supplied to the dimming disc 40. By supplying the AC voltage to the dimming disc 40 starting from the phase of 0 degrees or 180 degrees, the peak current of the inrush current when the AC current supply to the dimming disc 40 begins can be suppressed. Thus, the inrush current in the dimming disc 40 can be suppressed. Furthermore, suppressing the inrush current refers, for example, to suppressing the peak current of the inrush current, but it can also mean reducing the number of times the inrush current occurs.

[0113] In addition, the display device 10 includes a microcomputer 81 that controls the AC voltage supplied to the dimming disc 40 and outputs a PWM waveform from the microcomputer 81.

[0114] Therefore, compared to using analog circuits to generate PWM waveforms, it is possible to control the AC voltage at 0 degrees or 180 degrees with good precision. This further suppresses the inrush current to the dimming disc 40.

[0115] Furthermore, the display device 10 includes a light-transmitting display panel 30 disposed overlapping with the dimming disc 40. In the control method of the display device 10, after the supply of a DC voltage to the display panel 30 corresponding to the operation of turning on the display device 10 begins, the supply of an AC voltage to the dimming disc 40 corresponding to that operation also begins.

[0116] This allows for more precise control over the phase (0 degrees or 180 degrees) of the AC voltage when the dimming disc 40 is turned on. Consequently, it further suppresses the inrush current to the dimming disc 40.

[0117] Furthermore, when the operation of turning off the display device 10 is achieved ("Yes" in S201), after the supply of DC voltage to the display panel 30 is stopped in response to the operation, the supply of AC voltage to the dimming disc 40 is stopped in response to the operation.

[0118] Therefore, compared to the case where the AC voltage supply is stopped at the timing of stopping the DC voltage supply to the display panel 30, the phase of the AC voltage when the dimming disc 40 is turned off can be controlled to 0 degrees or 180 degrees (e.g., a zero-volt phase). This allows for the suppression of discharge current from the dimming disc 40.

[0119] Furthermore, the AC voltage supply is stopped when the phase of the AC voltage is 0 degrees or 180 degrees. Additionally, stopping the output of the PWM waveform (S203) is another example of stopping the AC voltage supply.

[0120] This further suppresses the discharge current generated when the dimming disc 40 is turned off. In other words, it further suppresses damage to the electrodes of the dimming disc 40 due to the discharge current. Therefore, a display device 10 with further improved reliability can be achieved.

[0121] In addition, the dimming disc 40 can switch to one or more intermediate states between transparent and opaque states.

[0122] As a result, the display device 10 can control the transmittance of the dimming disc 40 in finer increments, thus suppressing the degradation of the aesthetics of the images displayed on the display panel 30 and the background of the display device 10 (e.g., objects or scenery behind the display device 10).

[0123] Furthermore, the higher the illuminance of the environment in which the display device 10 is configured, the more the dimming disc 40 is controlled to be in a state with lower transmittance among more than one intermediate state.

[0124] Therefore, the display device 10 can suppress the decrease in the aesthetics of the image displayed on the display panel 30 and the background of the display device 10 due to increased ambient illuminance. For example, when the display device 10 is installed outdoors or mounted in a moving vehicle such as a car or tram, the decrease in aesthetics can be effectively suppressed.

[0125] Furthermore, the higher the illuminance of the object viewed by the viewer through the display device 10, the more the dimming plate 40 is controlled to a state with lower transmittance among more than one intermediate state.

[0126] Therefore, the display device 10 can suppress the decrease in the aesthetics of the image displayed on the display panel 30 due to the increase in ambient illuminance.

[0127] Furthermore, regardless of whether the transition is from a transparent state, an opaque state, or one or more intermediate states, a PWM waveform based on a DC voltage generated at an AC voltage phase of 0 degrees or 180 degrees with a load factor of 50% can be output. This PWM waveform is output, for example, by a microcomputer 81.

[0128] Therefore, regardless of how the dimming disc 40 switches its state, that is, even if various AC voltages are supplied to the dimming disc 40, the generation of inrush current can be suppressed.

[0129] Furthermore, the DC voltage for one of the more than one intermediate state may be below a specified voltage, and an arbitrary PWM waveform may be output when switching to that intermediate state. This PWM waveform may be output by a microcomputer 81, for example.

[0130] Therefore, it can suppress the generation of large inrush currents, and thus effectively suppress inrush currents.

[0131] Furthermore, as described above, the display device 10 of this embodiment is a display device 10 equipped with a dimming disc 40 capable of switching between a transparent state and an opaque state. It includes: a microcomputer 81 (an example of a PWM waveform output unit) that, when the operation of turning on the display device 10 is obtained, outputs a PWM waveform that generates an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% based on a DC voltage; and a drive circuit 82 that generates an AC voltage from the DC voltage based on the output PWM waveform and outputs the generated AC voltage to the dimming disc 40.

[0132] Therefore, it achieves the same effect as the control method of the display device 10 described above.

[0133] Furthermore, the dimming disc 40 has a conductive paste 46 that accepts an AC voltage supply. The conductive paste 46 also has a current density of 500 mA / mm². 2 The following sizes.

[0134] Therefore, the current density becomes 500 mA / mm. 2 Therefore, localized heating caused by gap B is reduced. For example, even when an inrush current of about 200mA is generated, this localized heating can be reduced. As a result, damage to the electrodes of the dimming plate 40 can be further suppressed.

[0135] Furthermore, for example, in the comparative example display device where the electrode width W of the dimming disc 140 is 150 mm and the industrial power supply P1 is directly supplied to the dimming disc 140, an inrush current of approximately 200 mA flows. As a result, if the comparative example display device is turned on / off approximately 500 times, the electrode of the dimming disc 140 is damaged.

[0136] On the other hand, in the display device 10 of this embodiment, the electrode width W of the dimming disc 40 is 460 mm, and when the phases of the AC voltage are set to 0 degrees and 180 degrees with a load rate of 50%, and the dimming disc 40 is turned on and off at phases of 0 degrees and 180 degrees respectively, the inrush current can be suppressed to about 30 mA. As a result, the display device 10 of this embodiment can be turned on / off approximately 400,000 times. Thus, according to the display device 10 of this embodiment, the lifespan of the dimming disc 40 can be significantly improved.

[0137] (Other implementation methods)

[0138] The control method and display device of the display device of the embodiments and modifications (hereinafter also referred to as embodiments, etc.) have been described above, but the present invention is not limited to these embodiments, etc.

[0139] Therefore, the constituent elements described in the accompanying drawings and specific embodiments include not only those necessary for solving the problem, but also those not necessary for solving the problem, which are used to illustrate the above-described technology. Therefore, the mere presence of these non-essential constituent elements in the accompanying drawings and specific embodiments should not be used to directly determine that these non-essential constituent elements are essential.

[0140] For example, in the above embodiments, examples were described where the dimming sheet is transparent when an AC voltage is supplied and opaque when no AC voltage is supplied, but this is not a limitation. The dimming sheet may also be configured to be opaque when an AC voltage is supplied and transparent when no AC voltage is supplied.

[0141] Furthermore, the switching between the transparent or opaque state and intermediate states of the dimming disc in the above embodiments, as well as the switching between one intermediate state and other intermediate states among more than one intermediate state, can be controlled, for example, based on the ambient illuminance of the display device or a signal (image signal) input to the display device. In this case, the display device may include a control unit (not shown) that controls the DC power supply P2 to output a voltage value corresponding to the ambient illuminance of the display device or the image signal input to the display device. For example, the control unit can control the voltage value of the DC power supply P2 to set the transmittance of the dimming disc to one of three or more predetermined transmittances.

[0142] Alternatively, the control unit can be communicatively connected to the illuminance sensor, controlling the DC power supply P2 based on the illuminance obtained from the illuminance sensor. For example, if the illuminance around the display device is the same as the illuminance of the environment in which the display device is located, the control unit controls the voltage value of the DC power supply P2 such that the higher the illuminance, the lower the transmittance of the dimming disc. Alternatively, the control unit can be configured to maintain a state where the higher the illuminance, the lower the transmittance among one or more intermediate states.

[0143] Furthermore, for example, if the illuminance around the display device is the same as the illuminance of an object viewed through the display device by a viewer (e.g., an object positioned behind the display device), the control unit controls the voltage value of the DC power supply P2 so that the higher the illuminance, the lower the transmittance of the dimming disc. Alternatively, the control unit could be configured to control the transmittance to be lower in one or more intermediate states as the illuminance increases.

[0144] Additionally, the illuminance sensor may be included in the display device, for example. Furthermore, the illuminance sensor is configured to measure the illuminance of the environment or the illuminance of an object.

[0145] Furthermore, the control unit can also be configured to acquire the image signal input to the display device and control the DC power supply P2 based on the input image signal. For example, the control unit can also control the voltage value of the DC power supply P2 to achieve a value where the higher the average brightness of the image generated based on the image signal input to the display device, the lower the transmittance of the dimming disc. Alternatively, the control unit can be configured to control the transmittance to be lower in one or more intermediate states as the average brightness increases.

[0146] In addition, the control unit can also determine whether to proceed based on whether the DC voltage of the DC power supply P2 is below the specified voltage. Figure 10 and Figure 11 The operation is as shown. When the power supply to the dimming switch is turned on, the inrush current flowing through the dimming switch tends to increase with the applied voltage. Furthermore, when the power supply to the dimming switch is turned off, the discharge current flowing through the dimming switch tends to increase with the applied voltage just before the switch is turned off. In other words, when the voltage supplied to the dimming switch is lower, the inrush current and discharge current are smaller. Therefore, the control unit can determine that no operation is required when the DC voltage of the DC power supply P2 is below a specified voltage. Figure 10 and Figure 11 The microcomputer can also control the phase of the AC voltage based on the determination results of the control unit.

[0147] The microcomputer can, for example, output any PWM waveform when the DC voltage for one of the more than one intermediate state is below a specified voltage and when switching to that intermediate state. For example, the dimming disc may receive power from the industrial power supply P1 only when the DC voltage for one of the above intermediate states is below a specified voltage and when switching to that intermediate state. In this case, the dimming disc and the industrial power supply may be connected, for example, via a switch. The specified voltage is preset.

[0148] Furthermore, the microcomputer can perform control to suppress inrush current regardless of the DC voltage value of the DC power supply P2. For example, regardless of whether the transition is from a transparent state, an opaque state, or one or more intermediate states, the microcomputer outputs a PWM waveform of AC voltage with a phase of 0 degrees or 180 degrees and a load factor of 50% based on the DC voltage.

[0149] Alternatively, it could be, Figure 5 or Figure 8 One or more of the constituent elements shown (such as microcomputers) have the functions of the control unit described above.

[0150] Furthermore, the reinforcing plate in the higher-level embodiment may function as an operation acquisition unit that receives operations from the user. The reinforcing plate may, for example, be a touch panel.

[0151] Furthermore, an example in the above embodiment where the frame surrounds the front and back sides has been described, but it can also be configured to surround only the front side.

[0152] Furthermore, in the above embodiments, an example of not supplying DC power to the display unit was described, but it is not limited to this, and power may also be supplied to the display unit.

[0153] Furthermore, the use of the display device described in the above embodiments is not particularly limited; it can also be implemented as a television device or as a display window.

[0154] Furthermore, the order of the multiple processes described in the above embodiment is just one example. The order of the multiple processes can also be changed, or the multiple processes can be executed in parallel. Additionally, it is also possible to omit a portion of the multiple processes.

[0155] Furthermore, the constituent elements described in the above embodiments can also be implemented as software, typically as integrated circuits, i.e., LSIs. They can be implemented on a single chip, or partially or entirely on a single chip. Here, it is referred to as an LSI, but depending on the degree of integration, it may also be called an IC, system LSI, super LSI, or very large-scale LSI. In addition, the method of integrated circuit implementation is not limited to LSIs; it can also be implemented by dedicated circuits or general-purpose processors. FPGAs that can be programmed after LSI manufacturing, or reconfigurable processors that can reconfigure the connections or settings of the circuit units inside the LSI, can also be used. Furthermore, if an integrated circuit implementation technology that replaces LSIs emerges due to advancements in semiconductor technology or other derived technologies, this technology can of course be used to integrate the constituent elements.

[0156] Furthermore, the segmentation of functional blocks in the block diagram is one example. Multiple functional blocks can also be implemented as a single functional block, or a single functional block can be divided into multiple functional blocks, or some functionality can be transferred to other functional blocks. Additionally, the functions of multiple functional blocks with similar capabilities can be processed in parallel or in a time-sharing manner by a single piece of hardware or software.

[0157] Furthermore, in the implementation, each component may be constructed using dedicated hardware, or implemented by executing software programs suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing software programs recorded on a recording medium such as a hard disk or semiconductor memory.

[0158] In addition, the present invention also includes forms obtained by applying various modifications to the embodiments and variations that can be conceived by those skilled in the art, or forms achieved by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present invention.

[0159] Industrial availability

[0160] This invention is effective for display devices equipped with a dimming disc.

[0161] Label Explanation

[0162] 10 Display devices

[0163] 20 Reinforcing Plate

[0164] 30 Display Panel

[0165] 40 and 140 dimming films

[0166] 41, 43 substrate

[0167] 42 Light Adjustment Layer

[0168] 44, 45 ITO film

[0169] 46 Conductive paste

[0170] 47 Sealing tape

[0171] 50 Frame

[0172] 60 Operation Acquisition Department

[0173] 70 Power Supply Circuit No. 1

[0174] 80 Second power supply circuit

[0175] 81 Microcomputer

[0176] 82 drive circuit

[0177] 90 Conductivity band

[0178] B gap

[0179] C capacitor

[0180] E DC voltage

[0181] L Inductor

[0182] P1 Industrial Power Supply

[0183] P2 DC power supply

[0184] Transistors Q1, Q2, Q3, and Q4

[0185] Vout1 output voltage

[0186] Vout2 Output voltage (AC voltage)

[0187] W electrode width

Claims

1. A control method for a display device, comprising a dimming disc capable of switching between a transparent state and an opaque state, characterized in that, Upon achieving the first operation of turning on the aforementioned display device, a PWM waveform of an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% is generated based on the DC voltage. Based on the output PWM waveform, the AC voltage is generated from the DC voltage. The generated AC voltage is output to the dimming plate. The aforementioned dimming plate can switch to one or more intermediate states between the aforementioned transparent state and the aforementioned opaque state. When the DC voltage used for one of the above-mentioned intermediate states is below a specified voltage and the system switches to that intermediate state, an arbitrary PWM waveform is output.

2. The control method for the display device as described in claim 1, characterized in that, The aforementioned display device includes a microcomputer for controlling the AC voltage supplied to the aforementioned dimming disc; The aforementioned PWM waveform is output from the aforementioned microcomputer.

3. The control method for the display device as described in claim 1 or 2, characterized in that, The aforementioned display device includes a light-transmitting display panel disposed overlapping the aforementioned dimming sheet; After the voltage supply to the display panel is started in accordance with the first operation described above, the AC voltage supply to the dimming disc is started in accordance with the first operation.

4. The control method for the display device as described in claim 3, characterized in that, In the event of the second operation of turning off the display device, after stopping the voltage supply to the display panel in response to the second operation, the AC voltage supply to the dimming disc is stopped in response to the second operation.

5. The control method for the display device as described in claim 4, characterized in that, The supply of AC voltage is stopped when the phase of the AC voltage is 0 degrees or 180 degrees.

6. The control method for the display device as described in claim 1, characterized in that, The higher the illuminance of the environment in which the above-mentioned display device is configured, the lower the transmittance of the dimming sheet will be among the above-mentioned intermediate states.

7. The control method for the display device as described in claim 1, characterized in that, The higher the illuminance of the object viewed by the viewer through the display device, the lower the transmittance of the dimming disc will be among the above-mentioned intermediate states.

8. The control method for the display device as described in claim 1, characterized in that, Regardless of whether the switch occurs from the transparent state, the opaque state, or one or more intermediate states to other states, the output is the PWM waveform of the AC voltage generated based on the DC voltage at a phase of 0 degrees or 180 degrees with a load rate of 50%.

9. A display device comprising a dimming disc capable of switching between a transparent state and an opaque state, characterized in that, have: When the microcomputer achieves the operation of turning on the aforementioned display device, it outputs a PWM waveform of an AC voltage with a phase of 0 degrees or 180 degrees and a load rate of 50% based on the DC voltage. as well as The driving circuit is used to generate the AC voltage from the DC voltage based on the output PWM waveform, and output the generated AC voltage to the dimming disc. The aforementioned dimming plate can switch to one or more intermediate states between the aforementioned transparent state and the aforementioned opaque state. When the DC voltage used for one of the above-mentioned intermediate states is below a specified voltage and the system switches to that intermediate state, the microcomputer outputs an arbitrary PWM waveform.

10. The display device as claimed in claim 9, characterized in that, The aforementioned dimming disc has electrodes that receive the aforementioned AC voltage supply; The aforementioned electrodes have a current density of 500 mA / mm². 2 The following sizes.

Images