KR-102959963-B1 - PDLC in the form of electronic blinds

Abstract

The present invention discloses an electronic blind type PDLC. The present invention is configured such that, in an electronic blind type PDLC in which a plurality of domains are individually driven, a scattering state voltage for preventing afterimages is applied when a specific domain is changed from a transmission mode to a scattering mode. Accordingly, the liquid crystals of other domains are moved to an On state or an intermediate state for a short period of time before moving from the On (transmission mode) state to the initial Off (scattering mode) liquid crystal array state, thereby allowing the liquid crystal arrays of all domains to maintain the same scattering state. Through this, afterimages caused by haze differences between the individually driven plurality of domains can be effectively improved. In other words, by creating operating conditions similar to the environment in which the liquid crystal returns to its initial alignment state after the On state (transmission mode), it becomes possible to provide uniform image quality with improved afterimage across the entire window area in the Off state (scattering mode).

Inventors

• 김경진
• 김봉희
• 도효정

Assignees

• 주식회사 리비콘

Dates

Publication Date

20260508

Application Date

20250114

Claims (6)

1. delete
2. In configuring an electronic blind type PDLC having multiple domains that are electrically divided and individually driven by a control unit, When switching from transparent mode to scattering state, apply an off voltage as a voltage greater than or equal to the threshold voltage, specifically as a scattering state voltage for preventing afterimages exceeding 0V, wherein An electronic blind type PDLC that, when switching to scattering mode after applying voltage to a specific domain rather than the entire domain in transparent mode, applies an AC voltage (1~4V) greater than the threshold voltage of the liquid crystal as a scattering state voltage for preventing afterimages to a domain immediately adjacent to the specific domain or to all domains other than the specific domain.
3. In configuring an electronic blind type PDLC having multiple domains that are electrically divided and individually driven by a control unit, When switching from transparent mode to scattering state, apply an off voltage as a voltage greater than or equal to the threshold voltage, specifically as a scattering state voltage for preventing afterimages exceeding 0V, wherein An electronic blind type PDLC characterized by applying an AC voltage (5V~110V) greater than the threshold voltage of the liquid crystal within the range of 16.7 ms~120 ms to a domain immediately adjacent to the specific domain or all domains other than the specific domain when switching to a scattering mode after applying a voltage in a transparent mode to a specific domain rather than the entire domain.
4. In Article 2 or Article 3, An electronic blind type PDLC characterized by a liquid crystal transparency point of 110°C or higher constituting the above PDLC.
5. In Article 2 or Article 3, An electronically blind type PDLC in which the droplet size of the liquid crystal constituting the PDLC is 3㎛ or less and the liquid crystal/polymer thickness is 30㎛ or less.
6. A window of a vehicle, building, or conference room to which the electronic blind-type PDLC of either claim 2 or claim 3 is applied.

Description

Electronic blind type PDLC {PDLC in the form of electronic blinds} The present invention relates to a polymer dispersed liquid crystal display (hereinafter referred to as 'PDLC'), and more specifically, to an electron blind type PDLC that can reduce afterimages caused by the haze difference with surrounding domains when a specific domain changes from a transmission mode to a scattering mode in an electron blind type PDLC through laser etching. Generally, a polymer-dispersed liquid crystal display (PDLCD), as described in Registered Patent Publication No. 10-0269203, consists of liquid crystals dispersed within a polymer system. By applying a potential difference to the film, the liquid crystal molecules are aligned in the same direction as the light, allowing the incident light to pass through without scattering and appear transparent. The general manufacturing of PDLC films adopts a roll-to-roll method, in which a coating solution is applied to a lower ITO film, an upper ITO film is laminated, and then UV or thermal curing is performed to complete the PDLC film. If the ITO film is etched with a laser or the like during the manufacturing stage, a desired electron-blind type PDLC can be produced. This technology is well described in Registered Patent Publication No. 10-1618754. Meanwhile, the electronic blind type PDLC described above can individually drive multiple domains (D1, D2) as shown in the attached Fig. 1. However, when a specific domain (D2) that is individually driven is changed from a transmission mode to a scattering mode, it takes a long time (e.g., at least 1 hour) for the liquid crystal array to return to its previous initial state, so there is a problem in that afterimage (T1) occurs due to the haze difference between the scattering mode and another domain (D1). Therefore, it is necessary to improve the afterimage (T1) as described above, but current electronic blind type PDLCs have not attempted to improve the afterimage as described above. FIG. 1 is a configuration diagram showing a state in which a specific domain of the transmission mode in a conventional electronic blind type PDLC exhibits an afterimage when the same scattering mode as the neighboring domain is individually driven. FIG. 2 is a configuration diagram showing an improved afterimage state when a specific domain of the transmission mode in an electronic blind type PDLC is individually driven with the same scattering mode as an adjacent domain, as an embodiment of the present invention. FIG. 3 is a diagram showing the process of a liquid crystal responding to an electric field in an electronic blind type PDLC as an embodiment of the present invention. FIG. 4(a) is a waveform of a conventional driving voltage, and FIG. 4(b) is a voltage waveform in scattering and transmission modes for improving the afterimage of individually driven domains in an electronic blind type PDLC as an embodiment of the present invention. FIG. 5(a) is a photographic drawing of a PDLC showing a conventional state where afterimage is not improved, and FIG. 5(b) is a photographic drawing of a PDLC in which afterimage is improved by applying a scattering state voltage for afterimage prevention to individually driven domains in an electronic blind type PDLC. Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. FIG. 2 is a configuration diagram showing an improved afterimage state when a specific domain of the transmission mode in an electronic blind type PDLC is individually driven with the same scattering mode as an adjacent domain, as an embodiment of the present invention, and FIG. 3 is a diagram showing the reaction of a liquid crystal to an electric field in an electronic blind type PDLC as an embodiment of the present invention. Referring to the attached FIG. 2 and FIG. 3, the electronic blind type PDLC according to an embodiment of the present invention is an electronic blind type PDLC (10) having a first domain (D1) and a second domain (D2) that are electrically divided and individually driven by a control unit (20). In this state, the first domain (D1) is individually driven in a scattering mode, and the second domain (D2) is individually driven in a transmission mode by applying a driving voltage (e.g., 48V). In the prior art, the scattering mode voltage was 0V, but in the embodiment of the present invention, by applying a scattering state voltage for preventing afterimages that exceeds 0V as a voltage greater than or equal to the threshold voltage, the effect of preventing afterimages that occurs when switching from a transmission mode to a scattering mode, which is the objective of the present invention, can be achieved. Here, although not specifically illustrated, the electronic blind type PDLC (10) includes a first transparent conductive film layer, a liquid crystal/polymer layer laminated on the first transparent conductive film layer and controlling the liquid crystal (11) in a transm