KR900006884B1 - Electro-optic welding lens assembly - Google Patents

Abstract

The optical filter has its transmission controlled electrically in response to signals from an opto-electronic sensor and control. The filter's transmission is reduced as the received light intensity increases. The sensor and control include a transmission control loop whose setting member is formed by at least one filtering element. At least one sensor for transmission control is located in the radiation path of the filter's field of view and sited behind at least one transmission-controlled filtering element. A second opto-electronic sensor may be present to provide the supply current for transmission control. This powersupply sensor may lie behind a UV filter- transparent to IR.

Description

Electro-optical welding lens assembly

1 is a schematic diagram of a first embodiment.

2 is a schematic diagram of a second embodiment.

3 is a schematic diagram schematically showing a third embodiment;

4 is a side view of the lens assembly in the first embodiment

5 is a side view of the lens assembly in the second embodiment;

* Explanation of symbols for main parts of the drawings

FA: Filter Device Q: Power Supply

W: opto-electric converter element ST: stabilizer circuit

WR: oscillator S: photosensitive device

V1: Differential Amplifier TR: Trigger Circuit

SA: analog switch circuit P: potentiometer

V ₂ : power amplifier UV: UV filter element

IR: infrared filter element D ₁ and D ₂ : light shutter element

P ₁ , P ₂ : polarizer

The present invention relates to an electro-optic welding lens assembly that can be usefully used in a welder's helmet or protective goggles to protect the welder's eyes from the glare of a welding arc or a welding flame.

It is known that very bright ultraviolet and infrared rays are generated by gas welding as well as electric arc welding. Long exposure of the welder's eyes to these rays is very harmful. Therefore, the welder generally uses a helmet with a protective filter disposed in front of his eye, or a protective shield that includes a protective filter and works hand-held between the welder's eye and the welding arc or flame.

The fundamental problem with these protective measures is that the visible light is greatly reduced, making it difficult to see the working surface when the welder starts or after the end of the welding process.

US Patent No. 3,878, 804 describes a welder's helmet using a liquid crystal beam shutter assembly as a protective filter. One polarization filter element is in front of the shutter element and one polarization filter element is coupled to the two polarization filter elements at the back of the shutter element and the liquid crystal ray shutter, which passes through the filter assembly by applying an electric field across the liquid crystal material of the ray shutter. Can change the light transmission ratio. A more detailed description is described in US Pat. No. 3,878,804.

Better filtering can be achieved by the lens assembly as described in US Pat. No. 4,039,254. This patent describes a protective lens assembly that combines two or more liquid crystal light shutters and a liquid crystal shutter for a welding helmet in which at least three polarizers are selectively used in series to achieve a maximum light transmission of about 0.01% while the lens assembly is operating. Is being provided.

Although many similar protective lens assemblies are known, for example as described in US Pat. It has a common disadvantage. Therefore, these devices are not reliable because the batteries or accumulators are both consumed during the welding operation, and as a result the required protection effect is almost lost. In some cases, limited battery life may be a disadvantage because the lens assembly becomes maximally transparent when the batteries are exhausted and cannot guarantee the protective effect of the helmet or goggles. If the power supply does not operate, the lens assembly is in maximum light transmission, so the welder must remove the helmet or goggles before and after the welding operation.

Another disadvantage of known lens assemblies is the fact that these lens assemblies can only be switched between the maximum light transmission state and the minimum light transmission state, and cannot be switched in the intermediate state.

It is therefore an object of the present invention to solve the shortcomings described above and to provide an electro-optical welding lens assembly for use in a welder's helmet or goggles capable of operating independently of a battery or similar power supply means. . It is another object of the present invention to provide an electro-optical welding lens assembly that automatically adapts to existing ambient lighting by continuously changing the light transmission ratio between the minimum transmission state and the maximum transmission state of the ray. Another object of the present invention is to provide an electro-optic welding lens assembly having a longer service life and requiring only minor repairs in prolonged welding operations.

According to the present invention, there is provided at least one liquid crystal light shutter suitable for rotating the polarized light by 90 DEG, a first polarizer and a second polarizer disposed in front of the light shutter and behind the light shutter to be polarized in the same direction, and There is provided an electro-optic welding lens assembly for a welder's helmet or goggles including control means for generating an electrical signal connected to the beam shutter and for coupling the sensing means responsive to the ambient light condition. It changes in response to the amount of ambient light received by said sensing means to change the light transmission ratio through. The control means also includes opto-electric converter means coupled with at least one transducer member exposed to ambient light conditions and acting as a power supply for operating the control means.

Advantageously, said sensing means comprises at least one detector configured by the opto-electric converter member of the power supply. Preferably, the control means comprises an adjustment loop 1oop for controlling the light transmission ratio through the lens assembly, which is coupled to at least one adjustment member constituted by at least a portion of the lens assembly.

These and other features of the electro-optical welding lens assembly are described in more detail in the appended claims.

The above and other objects and features of the present invention will now be described in detail with reference to the accompanying drawings.

As can be seen in FIG. 1, a first embodiment of an electro-optical welding lens assembly includes a known filter apparatus FA as described in US Pat. No. 4,039,254. The transmission of light rays through this filter device is influenced by the control unit described below in detail. The power supply Q is connected to the filter device and the control device for supplying power.

The opto-electric lens assembly also includes an opto-electric converter element W exposed to the ambient light condition indicated by the arrow in the figure, a safety device circuit ST and an oscillator WR connected in series with the converter element W. ). The control device is combined with the sensing means and the control means to influence the transfer ratio of the filter apparatus comprising the photosensitive element S as a detector. (-) differential amplifier (V ₁₎ is positive (+) input terminal of it operates as a comparator circuit, an amplifier (V _l) is part of and connected to said sensing element (S), the amplifier (V ₁₎ input of the potentiometer It is connected to a taper and supplies a predetermined adjustable voltage to the negative input. The power supply terminal of the amplifier V ₁ is connected via a stabilizer circuit ST to a converter element W that transfers electrical energy in response to ambient light encountered on the converter element. The output terminal of the amplifier V ₁ is connected to the trigger circuit TR connected to the control terminal of the analog switch circuit SA. The switched terminal of the analog switch circuit SA is connected in series with a power supply circuit Q which provides a control signal to the liquid crystal light shutter element in the filter unit FA. As just described, the lens assembly is independent of a separate power supply means such as a battery and operates very reliably so that it can be precisely adjusted in relation to the switch limits.

In the second embodiment shown in FIG. 2, the sensing element S is arranged behind the filter device FA in the direction of the incoming light beam (arrow). Therefore, the adjustment loop for controlling the transmission ratio of the filter apparatus is realized, and the adjusting member becomes the filter apparatus FA. The differential amplifier V _l is connected as a comparator similar to the embodiment shown in FIG. 1, whereby the potentiometer P sets the negative input of the amplifier V _l to a selectable predetermined value. The output of the amplifier V ₁ is connected to a power amplifier V ₂ which drives the oscillator WR.

The remaining circuit configuration corresponds to the embodiment shown in FIG.

The embodiment according to FIG. 2 provides a lens assembly having a control device which makes the amount of light transmitted by the filter apparatus FA almost constant within a predetermined limit. Such lens assemblies can be used in a welder's helmet or protective goggles and allow the amount or intensity of light reaching the user's eye to remain fairly constant, regardless of the ambient light conditions, which can convert the intensity within wide limits. .

In Fig. 3 there is shown another embodiment which is capable of continuously controlling the light transmission through the filter apparatus which makes the intensity of the object illumination constant, the structure is simple, and requires only a few control circuit components. In this case, the converter element W disposed behind the filter apparatus FA when the light beam is transmitted acts as an opto-electric converter for supplying power to the control circuit while simultaneously adjusting the transmission ratio of the filter apparatus FA. It acts as a sensing member. The oscillator WR is directly connected to the transducer element W. If the converter element W operates at very good light intensity while the filter device FA is in a dark state and exhibits high internal resistance, a shunt potentiometer P is provided for adjusting the control circuit, Combine with high impedance input.

4 is a cross-sectional view of a filter apparatus FA having a transducer element W connected in parallel and a sensing element S connected in series. The drawing shown in FIG. For the sake of wide spread, the filter elements are actually arranged closely together. It can be seen from FIG. 4 that the transducer element W is arranged behind the ultraviolet filter element UV. This allows the transducer element W to operate at maximum efficiency, taking into account the sensitivity spectrum. On the other end of the ray path shown by the arrow in FIG. 4, an infrared filter element for blocking heat for the user of the lens assembly IR) is provided. An infrared filter element IR is provided as shown in dashed lines in FIG. As shown by the dotted line in FIG. 4, the infrared filter element IR may be disposed immediately after the ultraviolet filter element UV, that is, in front of the filter device FA. In a known method, the filter apparatus combines three light polarizers P ₁ earth P ₂ as well as two light shutter elements D ₁ , D ₃ , in which one light shutter element is behind the other shutter element.

Further, the embodiment according to FIG. 5 combines with two light shutter elements D ₁ , D ₂ , as shown in FIG. 4. However, the transducer element W operating simultaneously as the sensing element for the control circuit and the opto-electric power supply transducer is arranged behind one ray shutter element D _l . As a result, this operates with higher reliability since the lens assembly is exposed to greater light intensity when in the dark.

Claims (9)

A filtering device for welding arc protection, comprising: a beam filter (FA) having an electrically variable light transmission and an illumination corresponding to the illumination intensity by detecting an illumination intensity of an incident beam transmitted through at least a portion of the beam filter; Ray detection means (S, W) disposed in at least one portion of the ray filter in relation to the incident direction of the incident ray to generate an intensity signal, and receiving the illumination intensity signal from the ray detection means to Control means (ST, V1, TR, WR, P, V2) suitable for outputting an electrical signal opposite to the illumination intensity signal to the light beam filter to control the light transmission, and controlling the operating power supply Means and an electrical source (W) suitable for supplying the light filter. 2. The filtering device according to claim 1, wherein the electrical source comprises an opto-electric converter. 3. A filtering device according to claim 2, wherein said ray detection means comprises an opto-electric converter. In the second or claim 3, wherein the light filter has the first light beam shutter (D _l) adapted to convert the light transmission characteristic corresponding to the electric signal from the control means, associated with the incoming direction of the second The first polarizer P ₁ disposed in front of the one-ray shutter, the second polarizer D ₂ disposed behind the first light shutter in relation to the incident direction, and the second polarizer in relation to the incident direction. A second light shutter D ₂ arranged behind and adapted to change light transmission characteristics in response to the electrical signal from the control means, and a third disposed behind the second light shutter in relation to the direction of incidence Filtering apparatus comprising a polarizer (P ₃ ). The method of claim 4, wherein the light filter delivers ultraviolet light. And an infrared filter (IR) disposed in front of the first polarizer in relation to the incident direction, and an ultraviolet filter (UN) that transmits infrared rays and is disposed in front of the infrared filter in relation to the incident direction. Filtering device 5. The ultraviolet filter of claim 4, wherein the light beam filter transmits infrared rays and is disposed in front of the first polarizer in relation to the direction of incidence, and behind the third polarizer in relation to the direction of incidence. Filtering device comprising an infrared filter is disposed 7. The filtering apparatus according to claim 5 or 6, wherein the photo-electric converter is disposed behind the ultraviolet filter in relation to the direction of incidence. The filtering device according to claim 5 or 6, wherein the light detecting means is arranged behind the second polarizer in relation to the incident direction. 2. The filtering device according to claim 1, further comprising an adjusting circuit for adjusting the light transmission characteristics of the first and second light shutters, wherein the control means constitutes a part of the adjusting circuit.

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