<PAGE>

                        COMMON STOCK PURCHASE AGREEMENT

                                    between

                                 PIXTECH, INC.

                                      and

                         UNITED MICROELECTRONICS CORP.


                         dated as of February 14, 1997
<PAGE>

                               TABLE OF CONTENTS
<TABLE>
<CAPTION>

<C>          <S>                                                           <C>
SECTION 1.   Authorization of Sale of the Shares........................   1
             -----------------------------------

SECTION 2.   Sale of the Shares.........................................   1
             ------------------

SECTION 3.   Delivery of the Shares at the Closing......................   1
             -------------------------------------

SECTION 4.   Representations, Warranties and Covenants
             -----------------------------------------
             of PixTech.................................................   2
             ----------
    4.1      Organization and Qualification.............................   2
             ------------------------------
    4.2      Authorized Capital Stock...................................   2
             ------------------------
    4.3      Consents; Due Execution; Delivery and Performance
             -------------------------------------------------
             of the Agreement...........................................   2
             ----------------
    4.4      Issuance, Sale and.........................................   2
             ------------------
             Delivery of the Shares......................
             ----------------------
    4.5      Exempt Transaction.........................................   2
             ------------------
    4.6      Compliance with Rule 144...................................   2
             ------------------------
    4.7      Disclosure.................................................   3
             ----------
    4.8      Additional Information.....................................   3
             ----------------------
    4.9      No Material Changes........................................   3
             -------------------

SECTION 5.   Representations, Warranties and Covenants
             -----------------------------------------
             of UMC.....................................................   3
             ------
    5.1      Investment Considerations..................................   3
             -------------------------
    5.2      Due Execution, Delivery and Performance of the
             ----------------------------------------------
             Agreement..................................................   4
             ---------

SECTION 6.   Conditions to the Obligations of the
             ------------------------------------
             Purchasers.................................................   5
             ----------
    6.1      Accuracy of Representations and Warranties.................   5
             ------------------------------------------
    6.2      Performance................................................   5
             -----------
    6.3      Opinion of Counsel.........................................   5
             ------------------
    6.4      Closing of European Offering...............................   5
             ----------------------------
    6.5      Certificates and Documents.................................   5
             --------------------------
    6.6      Other Matters..............................................   5
             -------------

SECTION 7.   Conditions to the Obligations of PixTech...................   6
             ----------------------------------------
    7.1      Accuracy of Representations and
             -------------------------------
             Warranties.................................................   6
             ----------
    7.2      Performance................................................   6
             -----------

SECTION 8.   Survival of Representations, Warranties and
             -------------------------------------------
             Agreements; Assignability of Rights........................   6
             -----------------------------------

SECTION 9.   Registration Rights........................................   6
             -------------------
    9.1      Registration of Shares.....................................   6
             ----------------------
    9.2      Indemnification............................................   7
             ---------------
    9.3      "Stand-Off" Agreement......................................   8
             ---------------------
    9.4      Termination................................................   9
             -----------

SECTION 10.  Miscellaneous..............................................   9
             -------------
   10.1      Notices....................................................   9
             -------
</TABLE>
<PAGE>

<TABLE>
    <S>     <C>                                                          <C>
    10.2    Entire Agreement..........................................    9
            ----------------
    10.3    Assignment................................................   10
            ----------
    10.4    Amendments and Waivers....................................   10
            ----------------------
    10.5    Headings..................................................   10
            --------
    10.6    Severability..............................................   10
            ------------
    10.7    Governing Law.............................................   10
            -------------
    10.8    Counterparts..............................................   10
            ------------
    10.9    Expenses..................................................   10
            --------
    10.10   Publicity.................................................   10
            ---------
    10.11   Confidentiality...........................................   11
            ---------------
</TABLE>
<PAGE>

                        COMMON STOCK PURCHASE AGREEMENT


     THIS COMMON STOCK PURCHASE AGREEMENT dated as of February 14, 1997 (the
"Agreement") is made between PIXTECH, INC., a corporation organized under the
laws of the State of Delaware having its principal offices at Avenue Olivier
Perroy, Zone Industrielle de Rousset, 13790 Rousset France, ("PixTech"), and
United Microelectronics Corp., a corporation organized under the laws of the
Republic of China (Taiwan) having its principal offices at 2F, No. 76 Sec. 2,
Tunhwa S. Rd., Taipei, Taiwan, R.O.C. ("UMC").

                                 R E C I T A L

     PixTech desires to sell to UMC, and UMC desires to purchase from PixTech,
shares of PixTech's common stock on the terms described herein.

     NOW THEREFORE, in consideration of the premises and of the covenants herein
contained, the parties hereto mutually agree as follows:

     SECTION 1.  Authorization of Sale of the Shares.  Subject to the terms and
                 -----------------------------------
conditions of this Agreement, PixTech has authorized the sale to UMC of that
number of shares of the Common Stock, par value $0.01 per share (the "Common
Stock"), of PixTech equal to the quotient obtained by dividing $5,000,000 by the
per share price of the shares of Common Stock sold by PixTech in its European
offering (the "European Offering") pursuant to PixTech's Preliminary Prospectus
dated November 28, 1996, and any amendments or supplements thereto (the
"Prospectus").  Collectively, the shares of Common Stock which may be purchased
pursuant to this Section 1 are referred to herein as the "Shares."

     SECTION 2.  Sale of the Shares.  PixTech shall sell to UMC, and UMC shall
                 ------------------
purchase from PixTech, upon the terms and conditions hereinafter set forth, the
Shares, at a price per share equal to the price per share of the shares of
Common Stock sold by PixTech in its European Offering (as so determined, the
"Per Share Price").  The aggregate purchase price for the Shares (the "Aggregate
Purchase Price") shall be $5,000,000.

     SECTION 3.  Delivery of the Shares at the Closing.  The closing of the
                 -------------------------------------
purchase and sale of the Shares (the "Closing") shall occur on the date of the
closing of the European Offering or at such other time and date and at a place
to be agreed upon by PixTech and UMC (the "Closing Date").  Subject to the terms
and conditions of this Agreement, at the Closing, UMC shall pay to PixTech an
amount in cash or by wire transfer equal to the Aggregate Purchase Price and
PixTech shall deliver to UMC one or more stock certificates registered in the
name of UMC, or in such nominee name(s) as designated by UMC, representing the
number of Shares being purchased.


     SECTION 4.  Representations, Warranties and Covenants of PixTech.  PixTech
                 ----------------------------------------------------
hereby represents and warrants to, and covenants with, UMC as follows:
<PAGE>

          4.1  Organization and Qualification.  PixTech is a corporation duly
               ------------------------------
organized, validly existing and in good standing under the laws of the State of
Delaware and has all requisite corporate power and authority to conduct its
business as currently conducted.

          4.2  Authorized Capital Stock.  As of the date hereof, the authorized
               ------------------------
capital stock of PixTech consists of (a) 30,000,000 shares of common stock,
$0.01 par value per share, of which on January 27, 1996, 8,146,696 shares were
validly issued and outstanding, fully paid and non-assessable, and (b) 1,000,000
shares of undesignated preferred stock, $0.01 par value per share, none of which
are issued and outstanding.

          4.3  Consents; Due Execution; Delivery and Performance of the
               --------------------------------------------------------
Agreement.  PixTech's execution, delivery and performance of this Agreement (a)
---------
has been duly authorized under Delaware law by all requisite corporate action by
PixTech, (b) will not violate any law or the Restated Certificate of
Incorporation or Restated By-laws of PixTech or any other corporation of which
PixTech owns at least 50% of the outstanding voting stock (a "PixTech
Subsidiary") or any provision of any material indenture, mortgage, agreement,
contract or other material instrument to which PixTech or any PixTech Subsidiary
is a party or by which any of their respective properties or assets is bound as
of the date hereof or (c) require any consent by any person under, constitute or
result (upon notice or lapse of time or both) in a breach of any term, condition
or provision of, or constitute a default or give rise to any right of
termination or acceleration under any such indenture, mortgage, agreement,
contract or other material instrument or result in the creation or imposition of
any lien, security interest, mortgage, pledge, charge or other encumbrance, of
any material nature whatsoever, upon any properties or assets of PixTech or any
PixTech Subsidiary.  Upon its execution and delivery, and assuming the valid
execution thereof by UMC, the Agreement will constitute a valid and binding
obligation of PixTech, enforceable against PixTech in accordance with its terms,
except as enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or similar laws affecting creditors' and contracting
parties' rights generally and except as enforceability may be subject to general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law).

          4.4  Issuance, Sale and Delivery of the Shares.  When issued and paid
               -----------------------------------------
for, the Shares to be sold hereunder by PixTech will be validly issued and
outstanding, fully paid and non-assessable.

          4.5  Exempt Transaction.  Subject to the accuracy of UMC's
               ------------------
representations in Section 5.1 of this Agreement, the issuance of the Shares
will constitute a transaction exempt from the registration requirements of
Section 5 of the Securities Act of 1933, as amended (the "Securities Act") in
reliance upon Section 4(2) of the Securities Act and the regulations promulgated
pursuant thereto.

          4.6  Compliance with Rule 144.  At the written request of UMC at any
               ------------------------
time and from time to time, PixTech shall furnish to UMC, within three days
after receipt of such request, a written statement confirming PixTech's
compliance with the filing requirements of the Securities and Exchange
Commission (the "SEC") set forth in SEC Rule 144 as amended from time to time.
<PAGE>

          4.7  Disclosure.  Neither this Agreement, nor any other items prepared
               ----------
or supplied to UMC by or on behalf of PixTech with respect to the transactions
contemplated hereby contain any untrue statement of a material fact or omit a
material fact necessary to make each statement contained herein or therein not
misleading.  There is no fact which PixTech has not disclosed to UMC in writing
and of which any of its directors or executive officers is aware (other than
general economic conditions) and which has had or would reasonably be expected
to have a material adverse effect upon the financial condition, operating
results, assets, customer or supplier relations, employee relations or business
prospects of PixTech or PixTech Subsidiaries taken as a whole.

          4.8  Additional Information; Eligibility for Use of Form S-3.  All
               -------------------------------------------------------
reports filed by PixTech with the SEC pursuant to the reporting requirements of
the Securities Exchange Act of 1934, as amended (the "Exchange Act"), when
filed, did not contain any untrue statement of a material fact or omit to state
any material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances in which they were made, not
misleading.  PixTech has made all filings with the SEC which it is required to
make, and PixTech has not received any request from the SEC to file any
amendment or supplement to any such reports.  PixTech meets the eligibility
requirements set forth in paragraph I of the General Instructions to Form S-3
for the use of such Form for the registration of securities in a transaction
involving secondary offerings, as described in such General Instructions.

          4.9  No Material Changes.  As of the date hereof, there has been no
               -------------------
material adverse change in the financial condition or results of operations of
PixTech since the filing date of PixTech's last report with the Securities and
Exchange Commission pursuant to the reporting requirements of the Exchange Act.

     SECTION 5.  Representations, Warranties and Covenants of UMC.
                 ------------------------------------------------

          5.1  Investment Considerations.  UMC represents and warrants to, and
               -------------------------
covenants with, PixTech that:

               (a) UMC is knowledgeable, sophisticated and experienced in
          making, and is qualified to make, decisions with respect to
          investments in shares presenting an investment decision like that
          involved in the purchase of the Shares, including investments in
          securities issued by companies comparable to PixTech, and has
          requested, received, reviewed and considered all information it deems
          relevant in making an informed decision to purchase the Shares;

               (b) UMC is acquiring the Shares in the ordinary course of its
          business and for its own account for investment only and with no
          present intention of distributing any of such Shares or any
          arrangement or understanding with any other persons regarding the
          distribution of such Shares;

               (c) UMC understands that the Shares are "restricted securities"
          under the federal securities laws inasmuch as they are being acquired
          from PixTech in a transaction not involving a public offering and that
          under such
<PAGE>

          laws and applicable regulations such securities may be resold without
          registration under the Securities Act only in certain limited
          circumstances.  In this connection UMC represents that it is familiar
          with SEC Rule 144, as presently in effect, and understands the resale
          limitations imposed thereby and by the Securities Act;

               (d) UMC will not, directly or indirectly, offer, sell, pledge,
          transfer or otherwise dispose of (or solicit any offers to buy,
          purchase or otherwise acquire or take a pledge of) any of the Shares
          except in compliance with the Securities Act, and the rules and
          regulations promulgated thereunder.

               (e) UMC qualifies as an "accredited investor" within the meaning
          of Rule 501(a)(3) of Regulation D promulgated under the Securities Act
          and is not a resident of any of the United States of America; and

               (f) It is understood that the certificates evidencing the Shares
          shall bear the following legend unless and until the resale of the
          Shares pursuant to an effective Registration Statement or until the
          Shares may be sold under Rule 144 without restrictions:

     THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933.
     THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE
     ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE
     SECURITIES UNDER SUCH ACT OR, IF REQUESTED BY PIXTECH, AN OPINION OF
     COUNSEL REASONABLY SATISFACTORY TO PIXTECH AND ITS COUNSEL, THAT SUCH
     REGISTRATION IS NOT REQUIRED UNDER SUCH ACT.

          5.2  Due Execution, Delivery and Performance of the Agreement.  UMC
               --------------------------------------------------------
further represents and warrants to, and covenants with, PixTech that (a) UMC is
a corporation duly organized, validly existing and in good standing under the
laws of the Republic of China (Taiwan) and has full right, power, authority and
capacity to enter into this Agreement and to consummate the transactions
contemplated hereby and has taken all necessary action to authorize the
execution, delivery and performance of this Agreement, (b) the execution,
delivery and performance of this Agreement will not violate any law or the
charter documents of UMC or any other corporation of which UMC owns at least 50%
of the outstanding voting stock (a "UMC Subsidiary") or any provision of any
material indenture, mortgage, agreement, contract or other material instrument
to which UMC or any UMC Subsidiary is a party or by which UMC, any UMC
Subsidiary, or any of their respective properties or assets is bound as of the
date hereof, or result in a breach of or constitute (upon notice or lapse of
time or both) a default under any such indenture, mortgage, agreement, contract
or other material instrument or result in the creation or imposition of any
lien, security interest, mortgage, pledge, charge or encumbrance, of any
material nature whatsoever, upon any assets of UMC or any UMC Subsidiary, and
(c) upon the execution and delivery of this Agreement, and assuming the valid
execution thereof by PixTech, this Agreement shall constitute a valid and
binding obligation of UMC enforceable in accordance with its terms, except as
enforceability may be limited by applicable
<PAGE>

bankruptcy, insolvency, reorganization, moratorium or similar laws affecting
creditors' and contracting parties' rights generally and except as
enforceability may be subject to general principles of equity (regardless of
whether such enforceability is considered in a proceeding in equity or at law).

     SECTION 6.  Conditions to the Obligations of the Purchasers.
                 -----------------------------------------------

          The obligations of UMC under this Agreement are subject to the
fulfillment, or the waiver by UMC, of the conditions set forth in this Section 6
on or before the Closing Date.

          6.1  Accuracy of Representations and Warranties.  Each representation
               ------------------------------------------
and warranty of PixTech contained in this Agreement shall be true on and as of
the Closing Date with the same effect as though such representation and warranty
had been made on and as of that date.

          6.2  Performance.  PixTech shall have performed and complied with all
               -----------
agreements and conditions contained in this Agreement required to be performed
or complied with by PixTech prior to or at the Closing.

          6.3  Opinion of Counsel.  UMC shall have received an opinion from
               ------------------
Palmer & Dodge LLP, counsel to PixTech, dated as of the Closing Date, addressed
to UMC, and substantially in the form attached hereto as Exhibit A.
                                                         ---------

          6.4  Closing of European Offering.  The European Offering shall have
               ----------------------------
closed.

          6.5  Certificates and Documents.  PixTech shall have delivered to
               --------------------------
counsel to UMC:

          (a)  a certificate of the Secretary or Assistant Secretary of PixTech
dated as of the Closing Date, certifying as to (i) the incumbency of officers of
PixTech executing this Agreement and all other documents executed and delivered
in connection herewith, (ii) a copy of the By-Laws of PixTech, as in effect on
and as of the Closing Date, and (iii) a copy of the resolutions of the Board of
Directors of PixTech authorizing and approving PixTech's execution, delivery and
performance of this Agreement, all matters in connection with this Agreement,
and the transactions contemplated thereby.

          (b)  a certificate, executed by the President of PixTech as of the
Closing Date, certifying to the fulfillment of all of the conditions to UMC's
obligations under this Agreement, as set forth in this Section 6.

          6.6  Other Matters.  All corporate and other proceedings in connection
               -------------
with the transactions contemplated at the Closing by this Agreement, and all
documents and instruments incident to such transactions, shall be reasonably
satisfactory in substance and form to UMC and its counsel, and UMC and its
counsel shall have received all such counterpart originals or certified or other
copies of such documents as they may reasonably request.
<PAGE>

     SECTION 7.  Conditions to the Obligations of PixTech.
                 ----------------------------------------

          The obligations of PixTech under this Agreement are subject to the
fulfillment, or the waiver by PixTech, of the conditions set forth in this
Section 7 on or before the Closing Date.

          7.1  Accuracy of Representations and Warranties.  Each representation
               ------------------------------------------
and warranty of UMC contained in this Agreement shall be true on and as of the
Closing Date with the same effect as though such representations and warranties
had been made on and as of that date.

          7.2  Performance.  UMC shall have performed and complied with all
               -----------
agreements and conditions contained in this Agreement required to be performed
or complied with by UMC prior to or at the Closing.

     SECTION 8.  Survival of Representations, Warranties and Agreements;
                 -------------------------------------------------------
Assignability of Rights.  Notwithstanding any investigation made by any party to
-----------------------
this Agreement, all covenants, agreements, representations and warranties made
by PixTech and UMC herein, except as otherwise provided herein, shall survive
the execution of this Agreement, the delivery to UMC of the Shares being
purchased and the payment therefor.  Except as otherwise provided herein, (i)
the covenants, agreements, representations and warranties of the Company made
herein shall bind the Company's successors and assigns and shall insure to the
benefit of UMC's successors and assigns and (ii) the covenants, agreements,
representations and warranties of UMC made herein shall bind UMC's successors
and assigns and shall insure to the benefit of PixTech's successors and assigns.

     SECTION 9.  Registration Rights.
                 -------------------

          9.1  Registration of Shares.  PixTech covenants and agrees that it
               ----------------------
will:

               (a) promptly following the Closing, prepare and file a
          registration statement on one or more Forms S-3 covering the resale of
          the Shares by UMC (or, if PixTech is not then eligible to use such
          Form, on any other form of registration statement promulgated by the
          SEC which would cover the resale of the Shares), and use its best
          efforts to cause such registration statement to become effective in
          order that UMC may sell its Shares in accordance with the proposed
          plan of distribution;

               (b) prepare and file with the Securities and Exchange Commission
          such amendments and supplements to such registration statement(s) and
          the prospectus used in connection therewith as may be necessary to
          keep such registration statement effective and to comply with the
          provisions of the Securities Act with respect to the resale of the
          Shares covered by such registration statement(s) until such time as
          UMC no longer holds any of the Shares;

               (c) furnish UMC such number of copies of such prospectus as it
          may reasonably request in order to facilitate the resale of the
          Shares;
<PAGE>

               (d) file documents required of PixTech for blue sky clearance in
          states specified in writing by UMC; provided, however, that PixTech
          shall not be required to qualify to do business or consent to service
          of process in any jurisdiction in which it is now not so qualified or
          has not so consented; and

               (e) bear all expenses in connection with the procedures set forth
          in paragraphs (a) through (d) of this Section 9 and the registration
          of the Shares pursuant to the registration statement, other than fees
          and expenses, if any, of counsel or other advisors to UMC.

          9.2  Indemnification.  For the purpose of this Section 9.2,
               ---------------

               (a) the term "Selling Stockholder" shall mean UMC and any
          officer, director, employee, agent, affiliate or person deemed to be
          in control of UMC within the meaning of Section 15 of the Securities
          Act or Section 20 of the Exchange Act;

               (b) the term "Registration Statement" shall mean any final
          prospectus, exhibit, supplement or amendment included in or relating
          to the registration statement referred to in Section 9.1; and

               (c) the term "untrue statement" shall mean any untrue statement
          or alleged untrue statement of, or any omission or alleged omission to
          state, in the Registration Statement a material fact required to be
          stated therein or necessary to make the statements therein, in the
          light of the circumstances under which they were made, not misleading.

     PixTech agrees to indemnify and hold harmless each Selling Stockholder from
and against any losses, claims, damages or liabilities to which such Selling
Stockholder may become subject (under the Securities Act or otherwise) insofar
as such losses, claims, damages or liabilities (or actions or proceedings in
respect thereof) arise out of, or are based upon, any untrue statement of a
material fact contained in the Registration Statement on the effective date
thereof, or arise out of any failure by PixTech to fulfill any undertaking
included in the Registration Statement and PixTech will reimburse such Selling
Stockholder for any reasonable legal or other expenses reasonably incurred in
investigating, defending or preparing to defend any such action, proceeding or
claim; provided, however, that PixTech shall not be liable in any such case to
       --------  -------
the extent that such loss, claim, damage or liability arises out of, or is based
upon, an untrue statement made in such Registration Statement in reliance upon
and in conformity with written information furnished to PixTech by or on behalf
of such Selling Stockholder specifically for use in preparation of the
Registration Statement, or any statement or omission in any Prospectus that is
corrected in any subsequent Prospectus that was delivered to UMC prior to the
pertinent sale or sales by UMC.

     UMC agrees to indemnify and hold harmless PixTech (and each person, if any,
who controls PixTech within the meaning of Section 15 of the Securities Act,
each officer of PixTech who signs the Registration Statement and each director
of PixTech) from and against any losses, claims, damages or liabilities to which
PixTech (or any such officer, director or controlling person) may become subject
(under the Securities Act or otherwise), insofar as
<PAGE>

such losses, claims, damages or liabilities (or actions or proceedings in
respect thereof) arise out of, or are based upon, any untrue statement of a
material fact contained in the Registration Statement on the effective date
thereof if such untrue statement was made in reliance upon and in conformity
with written information furnished by or on behalf of UMC specifically for use
in preparation of the Registration Statement, and UMC will reimburse PixTech (or
such officer, director or controlling person, as the case may be), for any legal
or other expenses reasonably incurred in investigating, defending, or preparing
to defend any such action, proceeding or claim; provided, however, that UMC
                                                --------  -------
shall not be liable for any statement or omission in any Prospectus that is
corrected in any subsequent Prospectus that was delivered to UMC prior to the
pertinent sale or sales by UMC.

     Promptly after receipt by any indemnified person of a notice of a claim or
the commencement of any action in respect of which indemnity is to be sought
against an indemnifying person pursuant to this Section 9.2, such indemnified
person shall notify the indemnifying person in writing of such claim or of the
commencement of such action, and, subject to the provisions hereinafter stated,
in case any such action shall be brought against an indemnified person and such
indemnifying person shall have been notified thereof, such indemnifying person
shall be entitled to participate therein, and, to the extent it shall wish, to
assume the defense thereof, with counsel reasonably satisfactory to such
indemnified person; provided, however, that the indemnifying person shall not
                    --------  -------
agree to a settlement of any such action without the consent of the indemnified
person, which consent shall not be unreasonably withheld.  After notice from the
indemnifying person to such indemnified persons of its election to assume the
defense thereof, such indemnifying person shall not be liable to such
indemnified person for any legal expenses subsequently incurred by such
indemnified person in connection with the defense thereof; provided, however,
                                                           --------  -------
that if there exists or shall exist a conflict of interest that would make it
inappropriate, in the opinion of counsel to the indemnified person, for the same
counsel to represent both the indemnified person and such indemnifying person or
any officer, director, employee, agent, affiliate or person deemed to be in
control of such indemnifying person within the meaning of either Section 15 of
the Securities Act or Section 20 of the Exchange Act, the indemnified person
shall be entitled to retain its own counsel at the expense of such indemnifying
person.  It is understood, however, that PixTech shall, in connection with any
one such action, suit or proceeding or separate but substantially similar or
related actions, suits, or proceedings in the same jurisdiction arising out of
the same general allegations or circumstances, be liable for the reasonable fees
and expenses of only one separate firm of attorneys (in addition to any local
counsel) at any time for all such indemnified parties not having actual or
potential differing interests with PixTech or among themselves.

          9.3  "Stand-Off" Agreement.  If UMC holds any Shares at such time as
               ---------------------
PixTech proposes, at any time after the Closing Date, to offer shares of its
Common Stock or other securities for sale in a registered underwritten public
offering, then UMC agrees not to sell or otherwise transfer or dispose of any
such Shares or other securities of PixTech held by it during the period
commencing 10 days prior to, and expiring 180 days after, such registered public
offering has become effective, provided, that all executive officers and
directors of PixTech enter into similar agreements.  PixTech may impose stop
transfer instructions with respect to the Shares or other securities subject to
the foregoing restriction until the end of any stand-off period.
<PAGE>

          9.4  Termination.  UMC's registration rights hereunder shall terminate
               -----------
as to any Shares upon the earlier of (i) three years after the Closing Date or
(ii) such time as no such Shares are held by UMC.

     SECTION 10.  Miscellaneous.
                  -------------

          10.1 Notices.  Any consent, notice or report required or permitted to
               -------
be given or made under this Agreement by one of the parties hereto to the other
shall be in writing, delivered personally or by facsimile (and promptly
confirmed by telephone, personal delivery or courier) or courier, postage
prepaid (where applicable), addressed to such other party at its address
indicated below, or to such other address as the addressee shall have last
furnished in writing to the addressor and shall be effective upon receipt by the
addressee.

     If to PixTech:  PixTech, Inc.
                     Avenue Olivier Perroy
                     Zone Industrielle de Rousset
                     13790 Rousset France
                     Telephone:  011 334 4229 1000
                     Telecopy:   011 334 4229 0509

     with a copy to: Palmer & Dodge LLP
                     One Beacon Street
                     Boston, Massachusetts 02108
                     Attention:  Michael Lytton, Esq.
                     Telephone:  (617) 573-0100
                     Telecopy:  (617) 227-4420
<PAGE>

     If to UMC:     United Microelectronic Corp.
                    2F, No. 76 Sec 2, Tunhwa S. Rd.
                    Taipei, Taiwan, R.O.C.
                    Attn:  Stan Hung
                    Telephone:  886-2-7006999, ext. 6966.6911
                    Telecopy:   886-2-7033839

    with a copy to: Peter J. Courture, Esq.
                    Law +
                    993 Highland Circle
                    Los Altos, California  94024
                    Telephone: (415) 968-8855
                    Telecopy:  (415) 968-8885

          10.2 Entire Agreement.  This Agreement contains the entire
               ----------------
understanding of the parties with respect to the subject matter hereof and
supersedes the Letter of Intent dated January 9, 1997 addressed to PixTech by
UMC.  All express or implied agreements and understandings, either oral or
written, heretofore made are expressly merged in and made a part of this
Agreement.

          10.3 Assignment.  Neither this Agreement nor any of the rights and
               ----------
obligations contained herein may be assigned or otherwise transferred by either
party without the consent of the other party; provided, however, that either
PixTech or UMC may, without such consent, assign its rights and obligations
under this Agreement (i) to any Affiliate, all or substantially all of the
equity interest of which is owned and controlled by such party or its direct or
indirect parent corporation, or (ii) in connection with a merger, consolidation
or sale of substantially all of such party's assets to an unrelated third party;
provided, however, that such party's rights and obligations under this Agreement
shall be assumed by its successor in interest in any such transaction and shall
not be transferred separate from all or substantially all of its other business
assets, including those business assets.  Any purported assignment in violation
of the preceding sentence shall be void.  Any permitted assignee shall assume
all obligations of its assignor under this Agreement.

          10.4 Amendments and Waivers.  This Agreement may not be modified or
               ----------------------
amended except pursuant to an instrument in writing signed by PixTech and UMC.
The waiver by either party hereto of any right hereunder or the failure to
perform or of a breach by the other party shall not be deemed a waiver of any
other right hereunder or of any other breach or failure by said other party
whether of a similar nature or otherwise.

          10.5 Headings.  The headings of the various sections of this Agreement
               --------
have been inserted for convenience of reference only and shall not be deemed to
be part of this Agreement.

          10.6 Severability.  In case any provision contained in this Agreement
               ------------
should be invalid, illegal or unenforceable in any respect, the validity,
legality and enforceability of the remaining provisions contained herein shall
not in any way be affected or impaired thereby.
<PAGE>

          10.7   Governing Law.  This Agreement shall be governed by and
                 -------------
construed in accordance with the laws of the State of Delaware (without giving
effect to the choice of law provisions thereof) and the federal law of the
United States of America.

          10.8   Counterparts.  This Agreement may be executed in two or more
                 ------------
counterparts, each of which shall constitute an original, but all of which, when
taken together, shall constitute but one instrument, and shall become effective
when one or more counterparts have been signed by each party hereto and
delivered to the other parties.

          10.9   Expenses.  Except as otherwise specifically provided herein,
                 --------
each party shall bear its own expenses in connection with this Agreement.

          10.10  Publicity.  Neither party hereto shall issue any press releases
                 ---------
or otherwise make any public statement with respect to the transactions
contemplated by this Agreement without the prior written consent of the other
party, except as may be required by applicable law or regulation.

          10.11  Confidentiality.  UMC acknowledges and agrees that any
                 ---------------
information or data it has acquired from PixTech, not otherwise properly in the
public domain, was and will be treated pursuant to the confidentiality
provisions of the Memorandum of Understanding between Unipac Optoelectronics
Corp. and PixTech.



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<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Common Stock
Purchase Agreement to be executed by their duly authorized representatives as of
the day and year first above written.


PIXTECH, INC.



By:   /s/ Jean-Luc Grand-Clement
     -------------------------------
     Jean-Luc Grand-Clement
     President and Chief Executive Officer


UNITED MICROELECTRONIC CORP.



By:  /s/ Robert Tsao
   ------------------------------------------

Title:   Chairman
      ---------------------------------------