amazon.com, Inc. v. barnesandnoble.com, Inc. And barnesandnoble.com, LLC

This is a patent infringement suit brought by Amazon.com, Inc. (“Amazon”) against barnesandnoble.com, inc., and bar-nesandnoble.com 11c (together, “BN”). Amazon moved for a preliminary injunction to prohibit BN’s use of a feature of its web site called “Express Lane.” BN resist *1347 ed the preliminary injunction on several grounds, including that its Express Lane feature did not infringe the claims of Amazon’s patent, and that substantial questions exist as to the validity of Amazon’s patent. The United States District Court for the Western District of Washington rejected BN’s contentions. Instead, the district court held that Amazon had presented a case showing a likelihood of infringement by BN, and that BN’s challenges to the validity of the patent in suit lacked sufficient merit to avoid awarding extraordinary preliminary injunctive relief to Amazon. The district court granted Amazon’s motion, and now BN brings its timely appeal from the order entering the preliminary injunction. We have jurisdiction to review the district court’s order under 28 U.S.C. § 1292(c)(1) (1994).

After careful review of the district court’s opinion, the record, and the arguments advanced by the parties, we conclude that BN has mounted a substantial challenge to the validity of the patent in suit. Because Amazon is not entitled to preliminary injunctive relief under these circumstances, we vacate the order of the district court that set the preliminary injunction in place and remand the case for further proceedings.

I

This case involves United States Patent No. 5,960,411 (“the '411 patent”), which issued on September 28, 1999, and is assigned to Amazon. On October 21, 1999, Amazon brought suit against BN alleging infringement of the patent and seeking a preliminary injunction.

Amazon’s patent is directed to a method and system for “single action” ordering of items in a client/server environment such as the Internet. In the context of the '411 patent, a client/server environment describes the relationship between two computer systems in which a program executing on a client computer system makes a service request from another program executing on a server computer system, which fulfills the request. See col. 1, 11. 10-31; col. 3,11. 31-33; col. 5,1. 56 to col. 6, 1. 21; Fig. 2. Typically, the client computer system and the server computer system are located remotely from each other and communicate via a data communication network.

The '411 patent describes a method and system in which a consumer can complete a purchase order for an item via an electronic network using only a “single action,” such as the click of a computer mouse button on the client computer system. Amazon developed the patent to cope with what it considered to be frustrations presented by what is known as the “shopping cart model” purchase system for electronic commerce purchasing events. In previous incarnations of the shopping cart model, a purchaser using a client computer system (such as a personal computer executing a web browser program) could select an item from an electronic catalog, typically by clicking on an “Add to Shopping Cart” icon, thereby placing the item in the “virtual” shopping cart. Other items from the catalog could be added to the shopping cart in the same manner. When the shopper completed the selecting process, the electronic commercial event would move to the check-out counter, so to speak. Then, information regarding the purchaser’s identity, billing and shipping addresses, and credit payment method would be inserted into the transactional information base by the soon-to-be purchaser. Finally, the purchaser would “click” on a button displayed on the screen or somehow issue a command to execute the completed order, and the server computer system would verify and store the information concerning the transaction.

As is evident from the foregoing, an electronic commerce purchaser using the shopping cart model is required to perform *1348 several actions before achieving the ultimate goal of the placed order. The '411 patent sought to reduce the number of actions required from a consumer to effect a placed order. In the words of the written description of the '411 patent:

The present invention provides a method and system for single-action ordering of items in a client/server environment. The single-action ordering system of the present invention reduces the number of purchaser interactions needed to place an order and reduces the amount of sensitive information that is transmitted between a client system and a server system.

Col. 3,11. 31-37. How, one may ask, is the number of purchaser interactions reduced? The answer is that the number of purchaser interactions is reduced because the purchaser has previously visited the seller’s web site and has previously entered into the database of the seller all of the required billing and shipping information that is needed to effect a sales transaction. Thereafter, when the purchaser visits the seller’s web site and wishes to purchase a product from that site, the patent specifies that only a single action is necessary to place the order for the item. In the words of the written description, “once the description of an item is displayed, the purchaser need only take a single action to place the order to purchase that item.” Col. 3,11. 64-66.

II

The '411 patent has 26 claims, 4 of which are independent. Independent claims 1 and 11 are method claims directed to placing an order for an item, while independent claim 6 is an apparatus claim directed to a client system for ordering an item, and independent claim 9 is an apparatus claim directed to a server system for generating an order. Amazon asserted claims 1-3, 5-12, 14-17, and 21-24 against BN. Although there are significant differences among the various independent and dependent claims in issue, for purposes of this appeal we may initially direct our primary focus on the “single action” limitation that is included in each claim. This focus is appropriate because BN’s appeal attacks the injunction on the grounds that either its accused method does not infringe the “single action” limitation present in all of the claims, that the “single action” feature of the patent is invalid, or both.

We set forth below the text of the claims pertinent to our deliberations (i.e., claims 1, 2, 6, 9, and 11), with emphasis added to highlight the disputed claim terms:

1. A method of placing an order for an item comprising:

under control of a client system,

displaying information identifying the item; and in response to only a single action being perfomed, sending a request to order the item along with an identifier of a purchaser of the item to a server system; under control of a single-action ordering component of the server system, receiving the request; retrieving additional information previously stored for the purchaser identified by the identifier in the received request; and generating an order to purchase the requested item for the purchaser identified by the identifier in the received request using the retrieved additional information; and fulfilling the generated order to complete purchase of the item whereby the item is ordered without using a shopping cart ordering model.

2. The method of claim 1 wherein the displaying of information includes displaying information indicating the single action.

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6. A client system for ordering an item comprising: an identifier that *1349 identifies a customer; a display component for displaying information identifying the item;

a single-action ordering component that in response to performance of only a single action, sends a request to a server system to order the identified item, the request including the identifier so that the server system can locate additional information needed to complete the order and so that the server system can fulfill the generated order to complete purchase of the item; and

a shopping cart ordering component that in response to performance of an add-to-shopping-cart action, sends a request to the server system to add the item to a shopping cart.

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9. A server system for generating an order comprising:

a shopping cart ordering component; and

a single-action ordering component including:

a data storage medium storing information for a plurality of users;

a receiving component for receiving requests to order an item, a request including an indication of one of the plurality of users, the request being sent in response to only a single action being performed; and

an order placement component that retrieves from the data storage medium information for the indicated user and that uses the retrieved information to place an order for the indicated user for the item; and an order fulfillment component that completes a purchase of the item in accordance with the order placed by the single-action ordering component.

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11. A method for ordering an item using a client system, the method comprising:

displaying information identifying the item and displaying an indication of a single action that is to be perfoimed to order the identified item; and

in response to only the indicated single action being performed, sending to a server system a request to order the identified item

whereby the item is ordered independently of a shopping cart model and the order is fulfilled to complete a purchase of the item.

The district court interpreted the key “single action” claim limitation, which appears in each of the pertinent claims, to mean:

The term “single action” is not defined by the patent specification.... As a result, the term “single action” as used in the '411 patent appears to refer to one action (such as clicking a mouse button) that a user takes to purchase an item once the following information is displayed to the user: (1) a description of the item; and (2) a description of the single action the user must take to complete a purchase order for that item.

With this interpretation of the key claim limitation in hand, the district court turned to BN’s accused ordering system. BN’s short-cut ordering system, called “Express Lane,” like the system contemplated by the patent, contains previously entered billing and shipping information for the customer. In one implementation, after a person is presented with BN’s initial web page (referred to as the “menu page” or “home page”), the person can click on an icon on the menu page to get to what is called the “product page.” BN’s product page displays an image and a description of the selected product, and also presents the person with a description of a single action that can be taken to complete a purchase order for the item. If the single action described is taken, for example by a mouse click, the person will have effected a *1350 purchase order using BN’s Express Lane feature.

BN’s Express Lane thus presents a product page that contains the description of the item to be purchased and a “description” of the single action to be taken to effect placement of the order. Because only a single action need be taken to complete the purchase order once the product page is displayed, the district court concluded that Amazon had made a. showing of likelihood of success on its allegation of patent infringement.

In response to BN’s contention that substantial questions exist as to the validity of the '411 patent, the district court reviewed the prior art references upon which BN’s validity challenge rested. The district court concluded that none of the prior art references anticipated the claims of the '411 patent under 35 U.S.C. § 102 (1994) or rendered the claimed invention obvious under 35 U.S.C. § 103 (1994).

Ill

The grant or denial of a preliminary injunction under 35 U.S.C. § 283 (1994) is within the sound discretion of the district court. Novo Nordisk of N. Am., Inc. v. Genentech, Inc., 77 F.3d 1364, 1367, 37 USPQ2d 1773, 1775 (Fed.Cir.1996). “An abuse of discretion may be established by showing that the court made a clear error of judgment in weighing relevant factors or exercised its discretion based upon an error of law or clearly erroneous factual findings.” Id.

As the moving party, Amazon is entitled to a preliminary injunction if it can succeed in showing: (1) a reasonable likelihood of success on the merits; (2) irreparable harm if an injunction is not granted; (3)a balance of hardships tipping in its favor; and (4) the injunction’s favorable impact on the public interest. Reebok Int’l Ltd. v. J. Baker, Inc., 32 F.3d 1552, 1555, 31 USPQ2d 1781, 1783 (Fed.Cir.1994). “These factors, taken individually, are not dispositive; rather, the district court must weigh and measure each factor against the other factors and against the form and magnitude of the relief requested.” Hybritech, Inc. v. Abbott Labs., 849 F.2d 1446, 1451, 7 USPQ2d 1191, 1195 (Fed.Cir.1988).

Irreparable harm is presumed when a clear showing of patent validity and infringement has been made. Bell & Howell Document Mgmt. Prods. Co. v. Altek Sys., 132 F.3d 701, 708, 45 USPQ2d 1033, 1039-40 (Fed.Cir.1997) (citing H.H. Robertson v. United Steel Deck, Inc., 820 F.2d 384, 390, 2 USPQ2d 1926, 1929-30 (Fed.Cir.1987)). “This presumption derives in part from the finite term of the patent grant, for patent expiration is not suspended during litigation, and the passage of time can work irremediable harm.” Id.

Our case law and logic both require that a movant cannot be granted a preliminary injunction unless it establishes both of the first two factors, ie., likelihood of success on the merits and irreparable harm. Vehicular Techs. Corp. v. Titan Wheel Int’l, Inc., 141 F.3d 1084, 1088, 46 USPQ2d 1257, 1259-60 (Fed.Cir.1998) (citing Reebok Int’l, 32 F.3d at 1555, 31 USPQ2d at 1783).

In order to demonstrate a likelihood of success on the merits, Amazon must show that, in light of the presumptions and burdens that will inhere at trial on the merits, (1) Amazon will likely prove that BN infringes the '411 patent, and (2) Amazon’s infringement claim will likely withstand BN’s challenges to the validity and enforceability of the '411 patent. Genentech, Inc. v. Novo Nordisk, A/S, 108 F.3d 1361, 1364, 42 USPQ2d 1001, 1003 (Fed.Cir.1997). If BN raises a substantial question concerning either infringement or validity, ie., asserts an infringement or invalidity defense that the patentee cannot *1351 prove “lacks substantial merit,” the preliminary injunction should not issue. Id.

Of course, whether performed at the preliminary injunction stage or at some later stage in the course of a particular case, infringement and validity analyses must be performed on a claim-by-claim basis. See, e.g., Bayer AG v. Elan Pharm. Research Corp., 212 F.3d 1241, 1247, 54 USPQ2d 1711, 1715 (Fed.Cir.2000) (“Literal infringement requires the patentee to prove that the accused device contains each limitation of the asserted claim(s).” (citations omitted)); Ortho Pharm. Corp. v. Smith, 959 F.2d 936, 942, 22 USPQ2d 1119, 1124 (Fed.Cir.1992) (concluding that all grounds of invalidity must be evaluated against individual claims, as required by the plain language of 35 U.S.C. § 282 (1994)). Therefore, in cases involving multiple patent claims, to demonstrate a likelihood of success on the merits, the patentee must demonstrate that it will likely prove infringement of one or more claims of the patents-in-suit, and that at least one of those same allegedly infringed claims will also likely withstand the validity challenges presented by the accused infringer.

Both infringement and validity are at issue in this appeal. It is well settled that an infringement analysis involves two steps: the claim scope is first determined, and then the properly construed claim is compared with the accused device to determine whether all of the claim limitations are present either literally or by a substantial equivalent. See, e.g., Young Dental Mfg. Co. v. Q3 Special Prods., Inc., 112 F.3d 1137, 1141, 42 USPQ2d 1589, 1592 (Fed.Cir.1997). Conceptually, the first step of an invalidity analysis based on anticipation and/or obviousness in view of prior art references is no different from that of an infringement analysis. “It is elementary in patent law that, in determining whether a patent is valid and, if valid, infringed, the first step is to determine the meaning and scope of each claim in suit.” Lemelson v. Gen. Mills, Inc., 968 F.2d 1202, 1206, 23 USPQ2d 1284, 1287 (Fed. Cir.1992). “A claim must be construed before determining its validity just as it is first construed before deciding infringement.” Markman v. Westview Instruments, Inc., 52 F.3d 967, 996 n. 7, 34 USPQ2d 1321, 1344 n. 7 (Fed.Cir.1995) (Mayer, J., concurring), aff'd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996).

Only when a claim is properly understood can a determination be made whether the claim “reads on” an accused device or method, or whether the prior art anticipates and/or renders obvious the claimed invention. See id. Because the claims of a patent measure the invention at issue, the claims must be interpreted and given the same meaning for purposes of both validity and infringement analyses. See SmithKline Diagnostics, Inc. v. Helena Labs. Corp., 859 F.2d 878, 882, 8 USPQ2d 1468, 1471 (Fed.Cir.1988). “A patent may not, like a ‘nose of wax,’ be twisted one way to avoid anticipation and another to find infringement.” Sterner Lighting, Inc. v. Allied Elec. Supply, Inc., 431 F.2d 539, 544 (5th Cir.1970) (citing White v. Dunbar, 119 U.S. 47, 51, 7 S.Ct. 72, 30 L.Ed. 303 (1886)). The court must properly interpret the claims, because an improper claim construction may distort the infringement and validity analyses. See Bausch & Lomb, Inc. v. Barnes-Hind/Hydrocurve, Inc., 796 F.2d 443, 450, 230 USPQ 416, 421 (Fed.Cir.1986).

IV

BN contends on appeal that the district court committed legal errors that undermine the legitimacy of the preliminary injunction. In particular, BN asserts that the district court construed key claim limitations one way for purposes of its infringement analysis, and another way when considering BN’s validity challenges. *1352 BN asserts that under a consistent claim interpretation, its Express Lane feature either does not infringe the '411 patent, or that if the patent is interpreted so as to support the charge of infringement, then the claims of the patent are subject to a severe validity challenge. When the key claim limitations are properly interpreted, BN thus asserts, it will be clear that Amazon is not likely to succeed on the merits of its infringement claim, or that BN has succeeded in calling the validity of the '411 patent into serious question. In addition, BN asserts that the district court misunderstood the teaching of the prior art references, thereby committing clear error in the factual predicates it established for comprehension of the prior art references.

Amazon understandably aligns itself with the district court, asserting that no error of claim interpretation and no clear error in fact-finding has occurred that would undermine the grant of the preliminary injunction. We thus turn to the legal gist of this appeal.

V

It is clear from the district court’s opinion that the meaning it ascribed to the “single action” limitation includes a temporal consideration. The “single action” to be taken to complete the purchase order, according to the district court, only occurs after other events have transpired. These preliminary events required pursuant to the district court’s claim interpretation are the presentation of a description of the item to be purchased and the presentation of the single action the user must take to complete the purchase order for the item.

Amazon defends this temporal interpretation based on statements made by the applicant during prosecution of the patent. These statements, set forth below, are significant, because they were made at the point in the file history where the claims were amended to include the single action limitation.

In remarks accompanying an amendment dated February 26, 1999, Amazon provided the following comments (not limited to specific claims) to explain proposed amendments to the claims and to “clarify that the claimed single-action ordering technology is different from the shopping cart metaphor”:

Applicants’ single action ordering technology facilitates electronic ordering of items by reducing the number of purchaser interactions needed to place an order and reducing the amount of sensitive information that is transmitted between a client computer and a server computer when placing an order. To order an item using single-action ordering technology, the purchaser first locates the item by browsing through a catalog of items, by searching for the item, by selecting a link to the item, or by using any other means for locating the item. Once the item is located, the purchaser need only perform a single action to generate an order for the item and to fulfill that generated order. The single action may be, for example, the selecting of a button that is displayed on the web page or the speaking of a command. Because information (e.g., billing and shipping) about the purchaser has been saved (e.g., from a previous purchase), that information can be combined with the identification of the located item to generate and fulfill an order when the single action is performed.

On its face, this passage from the file history establishes that once a purchaser has located an item by any means, only a single action is required to generate an order for the item. Amazon, however, would put a special reading on the concept of a purchaser locating an item by any means. In Amazon’s view of the file history, a purchaser has not located the item, for the purpose of counting the number of steps thereafter to generate the order, until the purchaser has made the decision to *1353 purchase the item. As applied to the present case, Amazon argues that display of information about an item on BN’s menu page does not indicate an item located with an intent to place the order; only after one moves from BN’s menu page to its product page has one “located” the item for purposes of placing the order by a single action. Since it only takes a single action on BN’s product page to place the order, Amazon contends that BN likely infringes the '411 patent.

Amazon’s reading of the key passage from the file history injects subjective notions into the infringement analysis. For example, if a would-be purchaser has made the decision to purchase an item before coming to BN’s menu page, and there the purchaser sees the item displayed, Anazon would have to concede that no single action taken after the item display would achieve placement of the order. Instead, the purchaser would need to take a first action to advance from the menu page to the product page, and then a second action to place the order. We are not prepared to assign a meaning to a patent claim that depends on the state of mind of the accused infringer. We thus reject Amazon’s special meaning for the location of an item to be purchased.

However, as we now discuss in detail, we ultimately agree with Amazon and construe all four independent claims (ie., claims 1, 6, 9, and 11) to call for the single action to be performed immediately after a display of information about an item and without any intervening action, but not necessarily immediately after the first display or every display.

Our analysis begins with the plain language of the claims themselves. The term “single action” appears in the independent claims of the '411 patent in the following forms: “in response to only a single action being performed” (claims 1 and 9), “single-action ordering component” (claims 1, 6, and 9), “in response to performance of only a single action” (claim 6), “in response to only the indicated single action being performed” (claim 11), and “displaying an indication of a single action that is to be performed to order the identified item” (claim 11).

In claims 1, 6, and 11, the context of the claim makes it clear that the single action is performed after some information about the item is displayed. Claim 1 provides for “displaying information identifying the item,” and then immediately recites that “in response to only a single action being performed,” a request to purchase the item is sent to a server system. Claim 6 provides for “a display component for displaying information identifying the item,” and then immediately recites “the single action ordering component that in response to performance of only a single action” sends a request to purchase the item to a server system. Claim 11 provides for “displaying information identifying the item and displaying an indication of the single action,” and then immediately recites that “in response to only the indicated single action being performed” a request to purchase the item is sent to a server system. The context also indicates that the single action is performed, or is capable of being performed, after information about the item is displayed, without any intervening action. Nothing suggests, however, that the single action must be performed after every display or even immediately after the first display of information. Claim 9 does not explicitly provide for displaying information. It merely recites that a request to order an item is “sent in response to only a single action being performed.” However, although claim 9 does not recite “displaying,” the written description defines the claim 9 language of “single action being performed” to require that information has been displayed.

The ordinary meaning of “single action” as used in the various claims is straightfor *1354 ward, but the phrase alone does not indicate when to start counting actions. Therefore, we must look first to the written description of the '411 patent for further guidance.

The written description supports a construction that after information is “displayed,” single-action ordering is an option available to the user, and the counting falls within the scope of the claim when single-action ordering is actually selected by the user. To the extent that the claims are considered ambiguous on this point, the written description defines “single action” to require as much. In the Summary of the Invention, the written description describes an embodiment that “displays information that identifies the item and displays an indication of an action ... [and][i]n response to the indicated action being performed” orders the item. Col. 2, 11. 54-59. Similarly, in the Detailed Description of the Invention, the written description states that “[o]nce the description of an item is displayed, the purchaser need only take a single action.” Col. 3,11. 65-66. This is consistent for all of the disclosed embodiments.

Therefore, neither the written description nor the plain meaning of the claims require that single action ordering be possible after each and every display of information (or even immediately after the first display of information). The plain language of the claims and the written description require only that single action ordering be possible after some display of information. Indeed, the written description allows for and suggests the possibility that previous displays of information will have occurred before the display immediately preceding an order.

The Detailed Description of the Invention describes the first figure (Fig.lA) by stating that “this example Web page [containing a summary description of the item] was sent ... when the purchaser requested to review detailed information about the item.” Col. 4, 11. 7-9 (emphasis added). Given that the written description earlier described on-line purchasing as involving “browsing” (col.l, 1.55), it is reasonable to conclude that some less detailed information about the item has already been displayed.

This passage also allows for the possibility that the purchaser sees a display of the less detailed information on an item, decides to browse elsewhere, then ultimately returns to obtain more detañed information on the item and to finally order it. Thus, there could be intermittent displays of information on an item, in addition to successive displays of information on an item, and each and every display need not have single action ordering eapabüity.

The above passages indicate that the written description is not concerned with what happens on every display of information, or even immediately after the first display, but only that there be some display from which single action ordering can be performed.

The prosecution history of the '411 patent also supports the above claim construction. In response to an office action, in the passage from the prosecution history cited earlier in this opinion, the patentee stated “a purchaser first locates the item [1] by browsing through a catalog of items, [2] by searching for the item, [3] by selecting a link to the item, or [4] by using any other means for locating the item. Once the item is located, the purchaser need only perform a single action to generate an order” (enumeration added). This enumeration of the various ways an item may be located allows for information on the item to be displayed prior to single action ordering being enabled. This is seen most clearly in the third enumerated method, “selecting a link to the item.” If it is to serve as “a link to the item” (emphasis added), then there must be some display of *1355 information on the item either in the link or around the link. Thus, information on the item may sometimes be displayed before “locating” the item (and, hence, before single action ordering is enabled).

Likewise, the first enumerated method (browsing) is explained in the written description to entail requesting “detailed information” about an item before single action ordering is enabled. This presumes that “un-detailed” or general information was previously displayed. Similarly, the second enumerated method (searching) commonly entails first displaying information on various items that match a search string, such as a list of all books written by a particular author or dealing with a particular subject. The purchaser than typically selects one of these items to receive more detailed information, at which point the selected item is presumably “located” and single action ordering is enabled.

VI

A

When the correct meaning of the single action limitation is read on the accused BN system, it becomes apparent that the limitations of claim 1 are likely met by the accused system. The evidence on the record concerning the operation of BN’s “Express Lane” feature is not in dispute. At the time that the '411 patent was issued, BN offered customers two purchasing options. One was called “Shopping Cart,” and the other was called “Express Lane.” The Shopping Cart option involved the steps of adding items to a “virtual” shopping cart and then “checking out” to complete the purchase. In contrast, the Express Lane option allowed customers who had registered for the feature to purchase items simply by “clicking” on the “Express Lane” button provided on the “detail page” or “product page” describing and identifying the book or other item to be purchased. The text beneath the Express Lane button invited users to “Buy it now with just 1 click!”

BN’s allegedly infringing web site thus may be characterized as having “page 1,” (the “menu” page) which displays a catalog-listing several items but which does not contain an “order” icon, and “page 2,” (the “product” or “detail” page) which includes information on one item and also shows an order icon. Someone shopping at this web site would look at the catalog on page 1 and perform a first click to go to page 2. Once at page 2, a second click on the ordering icon would cause the order request to be sent. Under the claim construction set forth herein, BN likely infringes claim 1 because on page 2, the item is there displayed (meeting step 1 of the claim) and only a single action thereafter causes the order request to be transmitted (meeting step 2). The method implemented on page 1 of the BN web site does not infringe, but the method on page 2 does. This has nothing to do with the state of mind of the purchaser, but simply reflects the ordinary meaning of the words of the claim in the context of the written description and in light of the prosecution history.

We recognize that under this construction, claim 1 would appear to read on the prior art shopping cart model (because the final page of a shopping cart model both displays the item to be purchased in a list of selected products and sends the order request signal in response to the single next action of clicking on the “confirm purchase” icon). However, the shopping cart model is expressly excluded from claim 1 by the whereby clause at the end of the claim.

We note that the district court concluded that “[b]arnesandnoble.com infringes claims 1, 2, 3, 5, 11, 12, 12, 14, 15, 16, 17, 21, 22, 23, [and] 24,” and “also infringes claims 6-10 of the '411 patent.” However, the relevant determination at *1356 the preliminary injunction stage is substantial likelihood of success by Amazon of its infringement claims, not a legal conclusion as to the ultimate issue of infringement. We therefore interpret the district court’s conclusions as determining that Amazon had demonstrated a substantial likelihood of establishing literal infringement of the enumerated claims.

B

According to the plain language of claim 2, the point of reference from which to start “counting clicks” does not begin until “information indicating the single action” to be performed is displayed (ie., when the “EXPRESS LANE” or “BUY NOW” button is displayed). Amazon is thus correct in its assertion that only a single action is required after that point to send a request to order an item using BN’s Express Lane feature. For this reason, we cannot say that BN raised a substantial question of noninfringement of claim 2 in the '411 patent with respect to the “single action” limitation at this stage in the litigation.

We point out that BN mounted an additional noninfringement argument with respect to claims 1, 2, and 11 based on the term “shopping cart model” in the “whereby” clause of those claims. Claims 1 and 2 require that the item be ordered “without using a shopping cart model.” Similarly, claim 11 requires that the item be ordered “independently of a shopping cart model.” Thus, according to BN, even if an ordering system accused of infringement used the claimed “single action” technology, it would still not infringe claims 1, 2, or 11 so long as the single action technology was used within the paradigm of a “shopping cart model.”

Accordingly, BN argues that, even if its Express Lane feature is said to use single action technology within the scope of the claims in the '411 patent, the Express Lane feature is nevertheless a “shopping cart model” because, according to the written description, “shopping cart model” should be construed to include models in which checkout happens automatically when an item is selected for purchase. In fact, the written description of the '411 patent does mention alternative prior art shopping cart models having the feature that “when a purchaser selects any one item, then that item is ‘checked out’ by automatically prompting the user for the billing and shipment information.” Col. 2, 11. 24-27. Thus, BN argues that its Express Lane system does not infringe because it is an embodiment of such an alternative shopping cart model admitted to be prior art in the written description of the '411 patent.

The district court construed “shopping cart model” to mean “a method for on-line ordering in which a user selects and accumulates items to be purchased while browsing a merchant’s site and then must proceed to one or more checkout or confirmation steps in order to complete the purchase.” BN argues that this interpretation contradicts the written description of the '411 patent because it allegedly excludes the alternative shopping cart models mentioned in the written description. However, we discern no error with the district court’s interpretation of “shopping cart model,” because it is consistent ■with the written description and with the comments made by Amazon discussing the term during prosecution of the '411 patent, as discussed earlier with reference to the “single action” limitation. The district court’s interpretation does not improperly exclude the alternative shopping cart models mentioned by BN, because although an item may be checked out automatically when using these alternative shopping cart models, the written description states that the user must still provide billing and shipping information (unless the information is “pre-filled” with information that was provided by the user when placing a previous *1357 order). Additionally, regardless of whether the “purchaser-specific order information” is pre-filled or not, the user must still perform at least one confirmation step once the purchaser is presented with the order web page to complete the purchase. See col. 2, 11. 24-36. It follows, then, that BN’s noninfringement argument based on characterizing its Express Lane feature as a “shopping cart model” fails because once a purchaser clicks on the “Express Lane” ordering button, no additional checkout or confirmation steps are required before a request to order the item is sent to the server system.

Having considered and rejected BN’s alternative noninfringement arguments, we find that Amazon has carried its merits burden with respect to likely infringement of Claim 2. We note there is some redundancy between claims 1 and 2 under the claim interpretation set forth herein. However, the two claims are not identical in scope. For example, claim 2 would not read on a method where the first page of a web site includes a textual message such as “click directly on the picture of any item displayed on any of the following pages to place an order.” Under such a method, there would never be a page where both the item and the single action to be taken to order the item would be displayed. Claim 2 would not be infringed by such a system, but claim 1 would.

C

We note further that Amazon has also made out its likelihood of success case with respect to infringement of claim 11. Claim 11 is similar to claim 2 because it also includes the limitation requiring “displaying an indication of a single action that is to be performed.” For the reasons noted above with respect to claim 2, the district court was correct in concluding that BN had not raised a substantial question of noninfringement regarding claim 11.

D

In view of our interpretation of “single action,” we find that the district court correctly concluded that BN had not raised a substantial question of noninfringement regarding claims 6 and 9 with respect to the “single action” limitation.

However, we note that BN also mounted an additional noninfringement argument with respect to claims 6 and 9 based on the terms “fulfill” and “fulfillment” in those claims. Claim 6 requires that the server system have the capability to “fulfill the generated order to complete purchase of the item.” Similarly, claim 9 requires that the single action ordering component of the server system must include “an order fulfillment component that completes a purchase of the item.” BN argues that “fulfill” and “fulfillment” refer to all of the steps required to pick the product from a warehouse shelf, pack it for shipment, and ship it to the customer. Presumably,