WO2025044968A1

WO2025044968A1 - Auto-darkening filter and auto-darkening system and welding mask comprising the same

Info

Publication number: WO2025044968A1
Application number: PCT/CN2024/114469
Authority: WO
Inventors: Peng Hu
Original assignee: Tecmen Electronics Co Ltd
Current assignee: Tecmen Electronics Co Ltd
Priority date: 2023-08-25
Filing date: 2024-08-26
Publication date: 2025-03-06
Anticipated expiration: 2026-02-25
Also published as: CN220323681U

Abstract

An auto-darkening filter, comprising a liquid crystal cell assembly for controlling the shading and a liquid crystal cell assembly for adjusting the hue, wherein the liquid crystal cell assembly for controlling the shading comprises at least one positive liquid crystal cell assembly which is in a bright state when a voltage is not applied and is in a dark state when a voltage is applied; the liquid crystal cell assembly for adjusting the hue is secured to one side of the liquid crystal cell assembly for controlling the shading, the liquid crystal cell assembly for adjusting the hue comprises a polarizer proximate to the one side of the liquid crystal cell assembly for controlling the shading, an analyzer distal to the one side of the liquid crystal cell assembly for controlling the shading, and an electrically controlled birefringent liquid crystal cell which is located between the polarizer and the analyzer and capable of adjusting the hue based on a driving voltage, wherein directions of polarization axes of the polarizer and the analyzer are not parallel to each other and the electrically controlled birefringent liquid crystal cell has a liquid crystal twisted angle of greater than 90 degrees. The present application further an auto-darkening system and a welding mask comprising the auto-darkening filter which enable simultaneous control of the shading and adjustment of the hue during a welding operation.

Description

Auto-darkening Filter and Auto-darkening System and Welding Mask Comprising the Same

Field

The present disclosure relates to the technical field of safety equipment for welding and cutting operations, in particular to an auto-darkening filter (ADF) used in auto-darkening welding helmets or masks, the present disclosure further relates to an auto-darkening system and a welding mask comprising the auto-darkening filter.

Background

A typical auto-darkening filter controls the transmissivity, i.e., the shading, of light with the aid of an assembly of UV/IR filters, polaroids, and a liquid crystal cell to achieve filtration of harmful wavelengths generated in operations such as welding etc., or shading control of the passage of a powerful light source, wherein the liquid crystal cell is set up to meet the Morgan (J. A. Morgan) condition such that a rotation of the polarization plane that occurs when a light passes through the liquid crystal layer is independent of a wavelength of the light. In other words, when the Morgan condition is met, after incident light with different wavelengths pass through the liquid crystal layer, respective polarization surface produces the same rotation angle, the specific rotation is almost invariable in a range of visible light, and the rotatory dispersion is substantially eliminated, in other words the concomitant dispersion of this shading control of the liquid crystal assembly cannot achieve a definite hue control, then in general, the hue of the auto-darkening filter is substantially the same as that of the light source, which filter can be regarded as a monochromatic filter.

In actual use, in view of different visual preferences, thus welding operators wish to be able to set up different hues such as warm-hued or cool-hued. For example, some operators wish the hue of the auto-darkening filter to be yellowish, while others wish the hue to be bluish, such that their vision may reach to a comfortable state during a welding process. In addition, as some welding operators are insensitive to certain hues for personal reasons, it is necessary to provide an assembly with its function of making the hue of the auto-darkening filter to be settable, such that the auto-darkening filter can meet the above requirements by providing a definite hue control in addition to a shading control.

It should be noted that the "Background" section only aids to appreciate the contents of the present disclosure, and therefore the contents disclosed in the "Background" section may include prior art that is not known to persons skilled in the art. The contents disclosed in the "Background" section does not mean that the contents or the problems to be solved by one or more embodiments of the present disclosure have been known or recognized by the persons skilled in the art prior to the filing of the application.

Summary

An object of the present disclosure is to overcome the defects in the above mentioned prior art, and to provide an auto-darkening filter with adjustable hue, a control system for controlling the same, and a welding mask comprising the above mentioned auto-darkening filter and the control system, which is capable of selectively adjusting between different hues according to the visual preference of the welding operators, thereby obtaining a more comfortable operation experience during the welding process, as compared with the existing products in the market.

In order to achieve the above object, the present disclosure provides an auto-darkening filter comprising a liquid crystal cell assembly for controlling the shading and a liquid crystal cell assembly for adjusting the hue, wherein the liquid crystal cell assembly for controlling the shading comprises at least one positive liquid crystal cell assembly which is in a bright state when a voltage is not applied and is in a dark state when a voltage is applied; the liquid crystal cell assembly for adjusting the hue is secured to one side of the liquid crystal cell assembly for controlling the shading, wherein the liquid crystal cell assembly for adjusting the hue comprises a polarizer (i.e., polarizing sheet) proximate to the one side of the liquid crystal cell assembly for controlling the shading, an analyzer (i.e., analyzing sheet) distal to the one side of the liquid crystal cell assembly for controlling the shading, and an electrically controlled birefringent liquid crystal cell which is located between the polarizer and the analyzer and capable of adjusting the hue based on a driving voltage, wherein directions of polarization axes of the polarizer and the analyzer are not parallel to each other and the electrically controlled birefringent liquid crystal cell has a liquid crystal twisted angle of greater than 90 degrees.

Preferably, the at least one positive liquid crystal cell assembly comprises two or more positive liquid crystal cell assemblies secured together and stacked on each other.

Preferably, an included angle between the polarization axes of the polarizer and the analyzer is in a range of greater than 15 degrees to 90 degrees.

Preferably, a filter for filtering ultraviolet and/or infrared light is further provided on the other side of the liquid crystal cell assembly for controlling the shading which is distal to the liquid crystal cell assembly for adjusting the hue.

Preferably, each of the at least one positive liquid crystal cell assembly comprises a positive liquid crystal cell and polaroids located on two sides of the positive liquid crystal cell in a traveling direction of the light.

Preferably, the liquid crystal cell assembly for adjusting the hue has a hue adjustable range between 380 and 780 nm, the electrically controlled birefringent liquid crystal cell has a delay of greater than 600 nm, and the driving voltage for the electrically controlled birefringent liquid crystal cell is between 0 and 4 V.

Preferably, liquid crystal molecules in the electrically controlled birefringent liquid crystal cell are arranged in any one of a DAP mode, an along-plane arrangement mode and a HAN mode.

According to another aspect of the present disclosure, there is provided an auto-darkening system for a welding mask, which system comprising an auto-darkening filter according to the above specification and a control system for controlling the same, the control system comprising: a micro control unit; a photoelectric sensor detection unit for detecting an operation of welding arcing; an operational parameter setting unit capable of pre-setting and inputting operational parameters in a standby state of the control system and transmitting the operational parameters to the micro control unit; and a liquid crystal driving circuit capable of transmitting driving voltages to the liquid crystal cell assembly for controlling the shading and to the liquid crystal cell assembly for adjusting the hue respectively, the micro control unit is communicatively coupled to the photoelectric sensor detection unit, the operational parameter setting unit and the liquid crystal driving circuit respectively in such a way that the micro control unit is capable of receiving a detected welding arcing signal from the photoelectric sensor detecting unit, receiving the operational parameters from the operational parameter setting unit, and transmitting driving signals to the liquid crystal driving circuit so as to adjust the shading and hue of the auto-darkening filter.

Preferably, the operational parameter setting unit comprises buttons, a knob or a touch screen for pre-setting and inputting the operational parameters; and/or the auto-darkening system further comprises an LED indicator light for indicating a warm or cool hue in current configuration.

According to another aspect of the present disclosure, there is provided a welding mask comprising a mask body and an auto-darkening system according to the above specification, wherein the auto-darkening filter in the auto-darkening system is mounted at a front opening of the mask body in such a manner that the liquid crystal cell assembly for controlling the shading faces outwardly and the liquid crystal cell assembly for adjusting the hue faces inwardly, and wherein the control system in the auto-darkening system is integrally mounted to the mask body.

Brief description of drawings

The foregoing and other aspects of the present disclosure will be more thoroughly understood and recognized below in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of the structure of an auto-darkening filter according to a preferred embodiment of the present disclosure;

FIG. 2 is a schematic block diagram of an auto-darkening system according to the present disclosure; FIG. 3 is a general schematic diagram of a welding mask according to the present disclosure.

Embodiments

In order to make the technical problem to be solved, the technical solution and the beneficial technical effect of the present disclosure clearer and more understandable, the present disclosure will be further described in detail hereinafter in conjunction with the accompanying drawings and exemplary embodiments. It should be understood that the specific embodiments described herein are only for explaining the present disclosure, and are not intended to limit the protection scope of the present disclosure. Unless expressly stated in the accompanying drawings, otherwise the dimensions, positions, etc., of various components, features, elements, etc., as well as any distances between them, are not necessarily drawn to scale, and may be disproportionate and/or exaggerated for the sake of clarity.

The terms used herein are only for the purpose of describing specific exemplary embodiments and are not intended to be limiting. As used herein, the singular forms "one, " "a, " and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be appreciated that the terms "comprising" , "including" and/or "composed of" when used in this specification, designate the presence of the described feature, integer, step, operation, element, and/or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components and/or combinations thereof. Unless otherwise indicated, when a range of values is enumerated, the upper and lower limits of the range, and any sub-ranges therebetween, are included. Unless otherwise indicated, terms such as "first" , "second" , and the like are used only to distinguish one element from another. For example, one element may be referred to a "first element" and similarly, another element may be referred to a "second element" and vice versa. Paragraph headings used herein are for organizational purposes only and should not be interpreted as limiting the subject matter described.

As used herein, "outer side" and "inner side" are defined relative to a distance from the operator's eyes. Wherein, the outer side refers to the side of the auto-darkening filter that is distal to the operator's eyes (i.e., the side of the welding mask that is incident with ambient light during operation) , and the inner side refers to the side of the auto-darkening filter that is proximate to the operator's eyes. Accordingly, "outward" or "toward the outer side" refers to a direction from the inner side to the outer side of the auto-darkening filter, while "inward" or "toward the inner side" refers to a direction from the outer side to the inner side of the auto-darkening filter.

Unless expressly indicated otherwise, the terms "about" , "approximately" , "substantially" and the like imply that quantities, dimensions, formulations, parameters, and other quantities and characteristics are not precise and necessary to be precise, but may be approximate and/or larger or smaller as desired.

Unless expressly indicated otherwise, all connections and all operative connections may be direct or indirect. Similarly, unless expressly indicated otherwise, all connections and all operative connections may be rigid or non-rigid.

Similar reference signs refer to similar elements throughout the specification. Thus, the same or similar reference signs may be described with reference to the other accompanying drawings, even if they are neither mentioned nor described in the corresponding accompanying drawings. Moreover, even elements that are not labeled with the reference signs may be described with reference to the other accompanying drawings.

FIG. 1 is a schematic diagram of a structure of an auto-darkening filter according to the present disclosure, in which the relationship of relative positions of various liquid crystal assemblies are clearly shown. It should be noted that the dotted lines in the figure are only for the purpose of more clearly showing each liquid crystal assembly respectively and do not indicate that they are not interconnected with each other. As shown in this figure, an auto-darkening filter 10 comprises a liquid crystal cell assembly 101 for controlling the shading and a liquid crystal cell assembly 102 for adjusting the hue, wherein the liquid crystal cell assembly 101 for controlling the shading includes at least one positive liquid crystal cell assembly, shown in this embodiment as being secured together by two positive liquid crystal cell assemblies 101a, 101b stacked on each other, wherein the positive liquid crystal cell assembly 101a includes a positive liquid crystal cell LCD1 and polaroids 1011a, 1012a provided on two sides thereof in a traveling direction of the light; and the positive liquid crystal cell assembly 101b includes a positive liquid crystal cell LCD2 and polaroids 1011b, 1012b provided on two sides thereof in a traveling direction of the light. Further, the liquid crystal cell assembly 102 for adjusting the hue is an electrically controlled birefringent liquid crystal cell assembly, which comprising a polarizer 1021 and an analyzer 1022 disposed opposite to each other, and an electrically controlled birefringent liquid crystal cell LCD3 located between the polarizer 1021 and the analyzer 1022, wherein directions of the polarization axes of the polarizer 1021 and of the analyzer 1022 are non-parallel to each other, and wherein the electrically controlled birefringent liquid crystal cell has a liquid crystal twisted angle of greater than 90 degrees. In this application, "non-parallel" means that the polarization axes of the polarizer 1021 and the analyzer 1022 have a significant included angle between each other, which angle is in a range of greater than 15 degrees to 90 degrees. More preferably, the polarization axes of the polarizer and of the analyzer are approximately perpendicular to each other, i.e., the included angle between the polarization axes is in a range of 75 degrees to 90 degrees. It should be noted that the included angle between the polarization axes recited herein refers to an included angle which is projected onto a polarization plane by respective polarization axis as viewing in the traveling direction of the light. In conjunction with FIG. 1, the electrically controlled birefringent liquid crystal cell LCD3 is provided on one side (in practice, the side proximate to the operator's eyes, i.e., the inner side) of the above mentioned positive liquid crystal cell assemblies rather than being sandwiched between the positive liquid crystal cell assemblies 101a and 101b. Further, the auto-darkening filter 10 may be provided with a filter 103 for filtering ultraviolet and/or infrared (UV/IR) light on one side (in practice, the side that is incident by ambient light, i.e., the outer side) of the positive liquid crystal cell assembly that is distal to the electrically-controlled birefringent liquid crystal cell assembly. As is readily appreciated by persons skilled in the art, the filter 103 may be embodied as an interference filter which reflects infrared light radiation and absorbs the ultraviolet component of the welding light, or it may be embodied by using a combination of filters that separately reflect and/or absorb the ultraviolet or infrared light, the purpose of the filter is to remove the component of invisible light from the high-intensity welding light that is harmful to the human eyes. In addition, each of the liquid crystal cell assemblies shown in the drawings can be driven respectively by different liquid crystal driving circuits (as described below) at specific driving voltages via electrical connectors (not shown) , such that when the auto-darkening filter 10 is in a standby state, both positive liquid crystal cells LCD1, LCD2 are not energized and in a bright state under standby, while the electrically-controlled birefringent liquid crystal cell LCD3 is in an initial default hue when being not energized; and when in a welding operation, both positive liquid crystal cells LCD1, LCD2 are energized to be in a dark state at operation, while the electrically controlled birefringent liquid crystal cell LCD3 is energized to be in a desired hue.

Further, FIG. 2 illustrates a schematic block diagram of an auto-darkening system according to the present disclosure. As shown, the auto-darkening system comprises an auto-darkening filter 10 as shown in FIG. 1 (each of liquid crystal cells LCD1, LCD2, and LCD3 is symbolically shown in the block diagram for simplicity) , and an ADF control system 20 for controlling the shading and hue of the auto-darkening filter 10. Wherein the ADF control system 20 comprises a micro control unit MCU, a photoelectric sensor detection unit 201 for detecting an operation of welding arcing, and a liquid crystal driving circuit 202, wherein the micro control unit MCU is communicatively coupled to the photoelectric sensor detection unit 201 and the liquid crystal driving circuit 202 respectively, such that the micro control unit MCU is capable of receiving a detected welding arcing signal from the photoelectric sensor detection unit 201 and transmitting a driving signal to the liquid crystal driving circuit 20; and the liquid crystal driving circuit 202, upon receiving the driving signal from the micro control unit MCU, is capable of transmitting corresponding driving voltages to the positive liquid crystal cells LCD1 and LCD2 in the liquid crystal cell assembly 101 for controlling the shading, and to the electrically controlled birefringent liquid crystal cell LCD3 in the liquid crystal cell assembly 102 for adjusting the hue as shown in FIG. 1 respectively, in order to achieve a dual adjustment of the shading and the hue of the auto-darkening filter. In addition, the ADF control system of the present application further comprises an operational parameter setting unit 203, the micro control unit MCU is capable of receiving operational parameters from the operational parameter setting unit 203 those are pre-set or input in a standby state. When a welding arcing occurs, the photoelectric sensor in the photoelectric sensor detection unit 201 detects a change in the ambient light, and after processing by an operational amplifier, the photoelectric sensor detection unit 201 transmits a detected welding arcing signal to the micro control unit MCU. The micro control unit MCU may set the shading and hue of the auto-darkening filter accordingly based on an intensity of the detected welding arcing, or based on the operator's own settings or inputs. The micro control unit MCU may contain a mono-chip computer, and during operation, the mono-chip computer reads the operational parameters those are pre-set or input by the user and outputs corresponding control signals to the liquid crystal driving circuit 202 to respectively control the positive liquid crystal cells LCD1, LCD2 to adjust the darkness presented by the welding arcing passing through the liquid crystals, and to control the electrically controlled birefringent liquid crystal cell LCD3 to adjust the hue presented by the welding arcing passing through the liquid crystal cell, thereby protecting the operator's eyes from being hurt and at the same time retaining the whole operating environment in a hue which is preferred by the operator.

FIG. 3 illustrates a general schematic diagram of a welding mask according to the present disclosure, the welding mask comprises a mask body 30 and an auto-darkening system as previously described in the specification, wherein the mask body 30 is used to be coupled to a headgear (not shown in the figure) to be worn on an operator's head. Further as shown, the auto-darkening filter 10 is mounted at a front opening of the mask body 30, being oriented such that the liquid crystal cell assembly for controlling the shading faces outwardly and the liquid crystal cell assembly for adjusting the hue faces inwardly, and wherein the ADF control system 20 is integrally mounted to the mask body 30.

In practice, the ADF control system 20 is firstly activated to enter a standby state, and in the standby state operational parameters are pre-set or input by means of the operational parameter setting unit 203, and the operational parameters are transmitted to the micro control unit MCU. Wherein the pre-set or input operational parameters include, but not limited to, welding parameters, ADF operating modes, ADF hue-adjustable color settings, as well as input and display modes of adjusting the hue, etc. Further, the welding parameters include, but not limited to, shading control parameters, sensitivity control parameters, delay control parameters, etc., and the ADF operating modes include, but not limited to, grinding, welding, cutting, etc. In the present application, the electrically controlled birefringent liquid crystal cell LCD3 is set at the factory with a high liquid crystal twisted angle (greater than 90°) and a high delay (greater than 600 nm) , and a preferred initial standby hue is shown as yellow of warm-hued by means of appropriate deflection settings of the polarizer 1021 and the analyzer 1022, and the driving voltage for the electrically controlled birefringent liquid crystal cell LCD3 is in a range of 0 to 4 V. In the case of being energized, it is achieved that the color changes to blue due to a reduction of the high delay under action of voltage. As for the input and display mode of the hue adjustment, the operational parameter setting unit 203 may include buttons 2031, and the hue to be adjusted is preferably input by a setting-up way of selecting the buttons, and the persons skilled in the art may also conceive of using a knob, a resistive or capacitive touch screen, etc., for adjusting a hue which is displayed via the auto-darkening filter; furthermore, the above mentioned ADF control system 20 preferably further includes a display device such as an LED indicator light 204. During operation, the micro control unit MCU transmits a driving signal to the LED indicator light 204 for displaying the current setting type of the hue preset, for example, as warm- hued or cool-hued, and the persons skilled in the art may likewise conceive of displaying the current setting type of the hue preset by means of LED, LCD display screens, etc.

Next, the welding arcing is detected by the photoelectric sensor in the photoelectric sensor detection unit 201. When the photoelectric sensor fails to detect an operation of welding arcing (for example, during a confirmation made by the operator to a welding workpiece or a welding site before welding, or in case of the operator terminating the operation of welding arcing after welding is completed) , there is no any welding arcing (working) signal generated and transmitted to the micro control unit MCU, at which time the ADF control system 20 is retained in the initial standby state, the positive liquid crystal cells LCD1 and LCD2 for controlling the shading are both in the state of not being energized, and at this time, the liquid crystal is in a bright state under standby, that is to say, the operator is able to clearly observe the working environment and its surrounding conditions through the auto-darkening filter. At the same time, the micro control unit MCU outputs a default hue setting signal to a corresponding liquid crystal driving circuit that drives the electrically controlled birefringent liquid crystal cell LCD3, at which time an electrically controlled voltage output by the liquid crystal driving circuit is 0 V. Accordingly, the electrically controlled birefringent liquid crystal cell LCD3 displays the initial standby hue of the above mentioned warmer (yellow) color, and the hue LED indicator light displays a hue indication which is preset in the standby state.

On the other hand, when the operator starts welding and performs an operation of welding arcing, the photoelectric sensor in the photoelectric sensor detection unit 201 detects the welding arcing and further transmits a detected welding arcing signal to the micro control unit MCU, the micro control unit MCU outputs control signals to corresponding liquid crystal driving circuit 202 that drives the positive liquid crystal cells LCD1, LCD2, and then the corresponding liquid crystal driving circuit 202 applies a certain voltage to the positive liquid crystal cells LCD1, LCD2, respectively, and the liquid crystal molecular arrangement state inside the LCD1, LCD2 is changed, at which time a polarization direction of the incident linearly polarized light will be perpendicular to a direction of the light-transmitting axis of the emergent polaroid and be blocked, and thus be in a dark state, wherein the shading is determined on the basis of shading control parameters which are pre-set or input through the operational parameter setting unit 203 in a standby state. At the same time, the micro control unit MCU also outputs the hue setting signal to a liquid crystal driving circuit that drives the electrically controlled birefringent liquid crystal cell LCD3, and the liquid crystal driving circuit outputs a corresponding electrically controlled voltage to the electrically controlled birefringent liquid crystal cell LCD3 in order to set the electrically controlled birefringent liquid crystal cell LCD3 to a preset working hue. When the preset working hue is warm (yellow) , the electrically controlled voltage of the electrically controlled birefringent liquid crystal cell LCD3 output from the liquid crystal driving circuit 202 is preferably set to 0 V; and when the preset working hue is cool (blue) , the electrically controlled voltage of the electrically controlled birefringent liquid crystal cell LCD3 output from the liquid crystal driving circuit 202 is preferably set to 3 V. In the present application, the electrically controlled voltage of the liquid crystal driving circuit 202 driving the electrically controlled birefringent liquid crystal cell LED3 is set in a range of 0 to 4 V, such that a hue adjustable range of the auto-darkening filter is between 380 and 780 nm, i.e., a maximum hue coverage range may be from red to purple, and the setting of the specific color can be achieved according to the adjustment of the electrically controlled voltage of the above-mentioned liquid crystal driving circuit 202.

To sum up, with the technical solution of the present disclosure, it is possible to further selectively adjust between different hues according to the visual preference of the welding operator on the basis of a traditional auto-darkening filter that controls the shading, thereby obtaining a more comfortable operating experience during the welding process.

It should be noted that the above specification explains and illustrates the principles of the present disclosure only by way of the preferred embodiment. However, the present disclosure is not limited to the specific structure in the above preferred embodiment, and various modifications can be made.

For example, in the above mentioned preferred embodiment, the liquid crystal cell assembly 101 for controlling the shading is explained in terms of two positive liquid crystal cells LCD1, LCD2. However, it is contemplated for persons skilled in the art to provide at least one positive liquid crystal cell. In the case where the auto-darkening filter is only provided with one positive liquid crystal cell for controlling the shading, the liquid crystal driving circuit can operate in a high-voltage and low-frequency state to achieve a low cost of a single liquid crystal sheet as well as to obtain a relatively good view field when the light transmissivity is high. And when the auto-darkening filter is provided with two or more positive liquid crystal cells, the corresponding liquid crystal driving circuit can operate in a low-voltage and high-frequency state, at which time the auto-darkening filter of multiple liquid crystal cells can adjust the light transmissivity in the dark state by partially altering the twisted state of the liquid crystal molecules.

Further, in the preferred embodiment as shown in FIG. 1, each positive liquid crystal cell 101a, 101b is provided with polaroids 1011a, 1012a and 1011b, 1012b on both sides along a traveling direction of the light, respectively, and the polaroids are secured to both sides of the positive liquid crystal cells with the aid of a pressure-sensitive adhesive and have a substantially perpendicular polarization direction. The corresponding liquid crystal driving circuit applies a perpendicular electric field to control the rotation of liquid crystal molecules within the liquid crystal layer to change the transmissivity of incident external light. In this case, each positive liquid crystal cell together with the polaroids on both sides thereof can be fabricated as a whole in a modular manner. In other words, in terms of the positive liquid crystal cells LCD1, LCD2 in the preferred embodiment, they can be fabricated as a modular part together with the polaroids on both sides thereof, and then a plurality of the modular parts can be arranged in a stacked manner to produce the liquid crystal cell assembly 101 for controlling the shading. Alternatively, common polaroids can be provided between a plurality of positive liquid crystal cells, that is to say, a polaroid between any two adjacent positive liquid crystal cells functions both as a polaroid for an emergent light side of the positive liquid crystal cell located on a relative outer side, and at the same time functions as a polaroid for an incident light side of the positive liquid crystal cell located on a relative inner side. In this case, a more uniform shading in the dark state can be obtained by shifting the polarization directions of the two polaroids located at the outermost and innermost sides of the positive liquid crystal cell assembly relative to a normal direction of the polarization direction of the polaroid located between the positive liquid crystal cells, thereby assisting the operator with detailed observations of the processed object.

In addition, the electrically controlled birefringent liquid crystal cell of the present application does not limit the arrangement of the liquid crystal molecules therein, a DAP mode (the long axis of the liquid crystal molecules is aligned perpendicularly with respect to the substrate surfaces between which the liquid crystal molecules are clamped) , an along-plane arrangement mode (the long axis of the liquid crystal molecules is aligned parallel with respect to the substrate surfaces between which the liquid crystal molecules are clamped) , and a HAN mode (the long axis of the liquid crystal molecules is aligned perpendicularly with respect to a substrate surface on one side and parallel with respect to the substrate surface on the other side) can be employed as needed.

The foregoing describes in details, with the aid of the accompanying drawings, feasible but non-limiting embodiments of the auto-darkening filter according to the present disclosure. For persons skilled in the art, modifications and additions to the technology and structure as well as re-combinations of features in respective embodiments should be considered to be included in the scope of the present disclosure without deviating from the scope and substance of the present disclosure as set forth in the following claims. Accordingly, such modifications and additions which are contemplated under the teachings of the present disclosure should be considered as part of the present disclosure. The scope of the present disclosure is limited by the following appended claims, and includes equivalents known at the time of the filing date of the present disclosure and equivalents not yet foreseen.

Claims

An auto-darkening filter (10) , characterized in that, comprising a liquid crystal cell assembly (101) for controlling the shading and a liquid crystal cell assembly (102) for adjusting the hue,

wherein the liquid crystal cell assembly (101) for controlling the shading comprises at least one positive liquid crystal cell assembly which is in a bright state when a voltage is not applied and is in a dark state when a voltage is applied;

the liquid crystal cell assembly (102) for adjusting the hue is secured to one side of the liquid crystal cell assembly (101) for controlling the shading, wherein the liquid crystal cell assembly for adjusting the hue (102) comprises a polarizer (1021) proximate to the one side of the liquid crystal cell assembly (101) for controlling the shading, an analyzer (1022) distal to the one side of the liquid crystal cell assembly (101) for controlling the shading, and an electrically controlled birefringent liquid crystal cell (LCD3) which is located between the polarizer (1021) and the analyzer (1022) and capable of adjusting the hue based on a driving voltage, wherein directions of polarization axes of the polarizer (1021) and the analyzer (1022) are not parallel to each other and the electrically controlled birefringent liquid crystal cell (LCD3) has a liquid crystal twisted angle of greater than 90 degrees.
The auto-darkening filter (10) as recited in claim 1, characterized in that, the at least one positive liquid crystal cell assembly comprises two or more positive liquid crystal cell assemblies (101a, 101b) secured together and stacked on each other.
The auto-darkening filter (10) as recited in claim 1, characterized in that, an included angle between the polarization axes of the polarizer (1021) and the analyzer (1022) is in a range of greater than 15 degrees to 90 degrees.
The auto-darkening filter (10) as recited in any one of claims 1-3, characterized in that, a filter (103) for filtering ultraviolet and/or infrared light is further provided on the other side of the liquid crystal cell assembly (101) for controlling the shading which is distal to the liquid crystal cell assembly (102) for adjusting the hue.
The auto-darkening filter (10) as recited in any one of claims 1-3, characterized in that, each of the at least one positive liquid crystal cell assembly comprises a positive liquid crystal cell and polaroids located on two sides of the positive liquid crystal cell in a traveling direction of the light.
The auto-darkening filter (10) as recited in any one of claims 1-3, characterized in that, the liquid crystal cell assembly (102) for adjusting the hue has a hue adjustable range between 380 and 780 nm, the electrically controlled birefringent liquid crystal cell (LCD3) has a delay of greater than 600 nm, and the driving voltage for the electrically controlled birefringent liquid crystal cell (LCD3) is between 0 and 4 V.
The auto-darkening filter (10) as recited in any one of claims 1-3, characterized in that, liquid crystal molecules in the electrically controlled birefringent liquid crystal cell (LCD3) are arranged in any one of a DAP mode, an along-plane arrangement mode, and a HAN mode.
An auto-darkening system for a welding mask, characterized in that, the auto-darkening system comprising an auto-darkening filter (10) as recited in any one of claims 1-7 and a control system (20) for controlling the same, the control system (20) comprising:

a micro control unit (MCU) ;

a photoelectric sensor detection unit (201) for detecting an operation of welding arcing;

an operational parameter setting unit (203) capable of pre-setting and inputting operational parameters in a standby state of the control system (20) and transmitting the operational parameters to the micro control unit (MCU) ; and

a liquid crystal driving circuit (202) capable of transmitting driving voltages to the liquid crystal cell assembly (101) for controlling the shading and to the liquid crystal cell assembly (102) for adjusting the hue respectively,

the micro control unit (MCU) is communicatively coupled to the photoelectric sensor detection unit (201) , the operational parameter setting unit (203) and the liquid crystal driving circuit (202) respectively in such a way that the micro control unit is capable of receiving a detected welding arcing signal from the photoelectric sensor detecting unit (201) , receiving the operational parameters from the operational parameter setting unit (203) , and transmitting driving signals to the liquid crystal driving circuit (202) so as to adjust the shading and hue of the auto-darkening filter (10) .
The auto-darkening system as recited in claim 8, characterized in that, the operational parameter setting unit (203) comprises buttons (2031) , a knob or a touch screen for pre-setting and inputting the operational parameters; and/or the auto-darkening system further comprises an LED indicator light (204) for indicating a warm or cool hue in current configuration.
A welding mask, characterized in that, comprising: a mask body (30) and an auto-darkening system as recited in claim 8 or 9, wherein the auto-darkening filter (10) in the auto-darkening system is mounted at a front opening of the mask body (30) in such a manner that the liquid crystal cell assembly (101) for controlling the shading faces outwardly and the liquid crystal cell assembly (102) for adjusting the hue faces inwardly, and wherein the control system (20) in the auto-darkening system is integrally mounted to the mask body (30) .