HQ 957510: Photosensors; Safety Light Curtains; Optical Coupled Sensors; Explanatory Notes 85.41(B) and (C); HQ 088341; Chapter 85, Note 5; 8536.50.80

Native CBP ruling rendition. Applicability is fact-specific; modification/revocation relationships and original publisher date are retained. Publisher sentinel year0001 means unknown date, not a historical legal adoption.

                            HQ 957510
                          March 21, 1995


CLA-2 CO:R:C:M 957510 DWS

CATEGORY: Classification

TARIFF NO.: 8541.40.80

Ms. Sandy M. Rickert
E. Besler & Company
P.O. Box 66361
Chicago, IL 60666-0361

RE: Photosensors; Safety Light Curtains; Optical Coupled Sensors;
    Explanatory Notes 85.41(B) and (C); HQ 088341; Chapter 85,
    Note 5; 8536.50.80

Dear Mr. Rickert:

     This is in response to your letter of August 26, 1994, on behalf of Micro Switch, to the Area
Director of Customs, New York Seaport, concerning the classification of photoelectric sensors
and safety light curtains under the Harmonized Tariff Schedule of the United States (HTSUS). 
We have also considered information provided in a letter dated November 4, 1994, from Micro
Switch, in preparing this ruling.

FACTS:

     The merchandise consists of photoelectric sensors and safety light curtains.  It is our
understanding that both items operate in a similar manner.  Each consists of a light emitting diode
(LED) and a photo darlington transistor.  Both of these components are mounted so that the light
emitted by the LED is directed at the surface of the photo darlington transistor.  This
configuration allows a target to be detected when the LED light path is interrupted.  The
photosensor will respond to a target's presence or absence using either digital or analog
intelligence to perform such functions as positioning, switching, measuring, and/or diagnostics. 
The safety light curtain will react to the interruption of the LED light path by shutting down a
power driven machine in which it is contained to protect the machine's operator.

     The subheadings under consideration are as follows:

     8536.50.80: [e]lectrical apparatus for switching or 
                 protecting electrical circuits, or for
                 making connections to or in electrical
                 circuits (for example, switches, relays, fuses,
                 surge suppressors, plugs, sockets, lamp-
                 holders, junction boxes), for a voltage not
                 exceeding 1,000 V: [o]ther switches: [o]ther.

     The general, column one rate of duty for goods classifiable
     under this provision is 4.8 percent ad valorem.

     8541.40.80: . . . : [p]hotosensitive semiconductor devices,
                 including photovoltaic cells whether or not 
                 assembled in modules or made up into panels;
                 light-emitting diodes: [o]ther: [o]ptical 
                 coupled isolators.

     Goods classifiable under this provision receive duty-free
     treatment.

ISSUE:

     Whether the photoelectric sensors and the safety light curtains are classifiable under
subheading 8536.50.80, HTSUS, as other electrical apparatus for switching electrical circuits, or
under subheading 8541.40.80, HTSUS, as optical coupled isolators.

LAW AND ANALYSIS:

     Classification of merchandise under the HTSUS is in accordance with the General Rules of
Interpretation (GRI's).  
GRI 1 provides that classification is determined according to the terms of the headings and any
relative section or chapter notes.

     In understanding the language of the HTSUS, the Harmonized Commodity Description and
Coding System Explanatory Notes may be utilized.  The Explanatory Notes, although not
dispositive or legally binding, provide a commentary on the scope of each heading of the HTSUS,
and are generally indicative of the proper interpretation of these headings.  See T.D. 89-80, 54
Fed. Reg. 35127, 35128 (August 23, 1989).  In part, Explanatory Notes 85.41(B) and (C) (pp.
1398 - 1399) states that:

             (B) PHOTOSENSITIVE SEMICONDUCTOR DEVICES

     This group comprises photosensitive semiconductor devices in 
     which the action of visible rays, infra-red rays or ultra-
     violet rays causes variations in resistivity or generates
     an electromotive force, by the internal photoelectric 
     effect. . . 

     The main types of photosensitive semiconductor devices are:

     (1) xxx

     (2) Photovoltaic cells, which convert light directly into 
         electrical energy without the need for an external 
         source of current.  Photovoltaic cells based on 
         selenium are used mainly in luxmeters and exposure
         meters.  Those based on silicon have a higher output
         and are used, in particular, in control and regulating
         equipment, for detecting light impulses, in 
         communication systems using fibre optics, etc.

         Special categories of photovoltaic cells are:

         (i) xxx

        (ii) Photodiodes (germanium, silicon, etc.), 
             characterised by a variation in resistivity when
             light rays strike their p n junction.  They are 
             used in automatic data processing (reading of 
             punched cards and tapes, data storage), as
             photocathodes in certain electronic tubes, in
             radiation pyrometers, etc.  Phototransistors and
             photothyristors belong to this category of 
             photoelectric receivers. . . 

       (iii) Photocouples and photorelays consisting of 
             electroluminescent diodes combined with 
             photodiodes, phototransistors or photothyristors.

     Photosensitive semiconductor devices fall in this heading
     whether presented mounted (i.e., with their terminals or
     leads), packaged or unmounted.

                    (C) LIGHT EMITTING DIODES

     Light emitting diodes, or electroluminescent diodes, 
     (based, inter alia, on gallium arsenide or gallium 
     phosphide) are devices which convert electric energy into
     visible, infra-red or ultra-violet rays.  They are used,
     e.g., for displaying or transmitting data in control 
     systems.

     In HQ 088341, dated February 26, 1991, we held that  photosensors, similar to the subject
merchandise, were classifiable under subheading 8541.40.80, HTSUS.  In that ruling, we stated
that:

     [t]he photosensor at issue consists of a LED and photo-
     transistor combined together as one unit.  An LED is 
     described with electroluminescent diodes as devices which
     convert electric energy into visible, infra-red or ultra-
     violet rays.  EN 85.41(C).  A phototransistor is described
     as a type of photoelectric receiver characterized by a 
     variation in resistivity when light rays strike its p n 
     junction.  EN 85.41(B)(2)(ii).  The phototransistor at issue
     operates by receiving rays from the LED which create a 
     variation in resistivity.  When these rays are interrupted,
     by a shaft or key in some cases, this variation in 
     resistivity ceases.  Accordingly, the photosensor satisfies
     the description of a photosensitive semiconductor device
     consisting of an electroluminescent diode combined with a
     phototransistor.

     Subheading 8541.40.80, HTSUS, provides for optical coupled
     isolators.  These are described as very small four-terminal
     electronic circuit elements that include in an integral
     package a light emitter and light detector.  McGraw-Hill
     Encyclopedia of Science and Technology (MH) (6th ed.), 
     vol. 12, p. 419 (1987).  The optical emitters most commonly
     used in an isolator are LEDs.  MH at 419.  As stated 
     previously, the photosensor contains a LED.  A type of light
     detector used in isolators are light-sensitive devices that
     modify a voltage or current such as phototransistors.  MH at
     419.  As stated previously, the subject photosensor contains
     a phototransistor.  Furthermore, a LED-silicon detector
     combination is cited as a type of optical coupled isolator.
     MH at 419.  A photo-darlington sensor is cited as a type of
     light detector used in a LED-silicon detector.  MH at 420.         Accordingly, the photosensor
satisfies the description of an       optical coupled isolator.

     It is our position that, as with the photosensors in HQ 088341, the subject photoelectric
sensors and the safety light curtains are classifiable under subheading 8541.40.80, HTSUS, as
optical coupled isolators.  In an optical isolator, the emitting and detecting devices are so
positioned that the majority of the emission from the emitter is optically coupled to the light-sensitive area of the detector.  This configuration uses an electronic input signal to cause an
electronic input signal without any electronic connection between the input (LED) and the output
(phototransistor) terminals.  The subject merchandise satisfies this description.  It is our
understanding that both the photoelectric sensors and the safety light curtains are configured in
such a way that the light emitted by the LED is optically coupled to the light-sensitive area of the
photo darlingtion transistor.  When the rays emitted by the LED are broken by a target, the
isolator is no longer coupled and does not produce an output signal.  In addition, no electrical
connection exists between the LED and photo darlington transistor within the merchandise. 
Therefore, based upon the information you have submitted, the merchandise satisfies the
descriptions of how an optical coupled isolator functions.

     Consideration was given to classification of the merchandise under subheading 8536.50.80,
HTSUS, as other electrical apparatus for switching electrical circuits.  However, as we stated in
HQ 088341, the merchandise does not meet any of the technical descriptions of switches, nor is
the merchandise similar to any of the exemplars listed under Explanatory Note 85.36.

     In part, chapter 85, note 5, HTSUS, states that:

     [f]or the classification of the articles defined in this 
     note, headings 8541 and 8542 shall take precedence over any
     other heading in the tariff schedule which might cover them 
     by reference to, in particular function, their function.

     Even if the photoelectric sensors and the safety light curtains were described under heading
8536, HTSUS, based upon chapter 85, note 5, HTSUS, classification of the merchandise under
heading 8541, HTSUS, would take precedence over classification under heading 8536, HTSUS.

     Therefore, the merchandise is classifiable under subheading 8541.40.80, HTSUS, as optical
coupled sensors.

HOLDING:

     The photoelectric sensors and the safety light curtains are classifiable under subheading
8541.40.80, HTSUS, as optical coupled sensors.

                            Sincerely,



                            John Durant, Director
                            Commercial Rulings Division