<PAGE>
                                                                     EXHIBIT 4.1

         COMMON STOCK                                           COMMON STOCK
INCORPORATED UNDER THE LAWS OF                                 SEE REVERSE FOR
   THE STATE OF CALIFORNIA                                   CERTAIN DEFINITIONS
                                                              CUSIP 269151 10 6


                                   [ESS LOGO]

THIS CERTIFIES THAT

                                    SPECIMEN

IS THE RECORD HOLDER OF

   FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, WITHOUT PAR VALUE, OF

                              ESS TECHNOLOGY, INC.

transferable on the books of the Corporation by the holder hereof in person or
by duly authorized attorney upon surrender of this Certificate properly
endorsed.

This Certificate is not valid unless countersigned and registered by the
Transfer Agent and Registrar.

WITNESS the facsimile seal of the Corporation and the facsimile signatures of
its duly authorized officers.

Dated:

                                     [SEAL]

            /s/ Peter Cohn                               /s/ Robert L. Blair
               SPECIMEN                                        SPECIMEN
               SECRETARY                                    PRESIDENT AND
                                                        CHIEF EXECUTIVE OFFICER


                                                   COUNTERSIGNED AND REGISTERED:
                                         CHASEMELLON SHAREHOLDER SERVICES L.L.C.
                                                    TRANSFER AGENT AND REGISTRAR

<PAGE>
        The Corporation is authorized to issue Common Stock and Preferred
Stock. The Board of Directors of the Corporation has authority to determine the
authorized number of shares of each series of Preferred Stock and to determine
or alter the rights, preferences, privileges and restrictions granted to or
imposed upon any wholly unissued series of Preferred Stock, and to increase or
decrease (but not below the number of shares of such series then outstanding)
the number of shares of any series subsequent to the issue of shares of that
series.

        A statement of the rights, preferences, privileges and restrictions
granted to or imposed upon the respective classes or series of shares of stock
of the Corporation, and upon the holders thereof as established by the Articles
of Incorporation or by any certificate of determination of preferences, and the
number of shares constituting each series or class and the designations
thereof, may be obtained by any shareholder of the Corporation upon request and
without charge from the Secretary of the Corporation at the principal office of
the Corporation.

        The following abbreviations, when used in the inscription on the face
of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<Table>
        <S>                                            <C>
        TEN COM   --  as tenants in common              UNIF GIFT MIN ACT -- ...................Custodian...............
        TEN ENT   --  as tenants by the entireties                                 (Cust)                    (Minor)
        JT TEN    --  as joint tenants with right of                         under Uniform Gifts to Minors
                      survivorship and not as tenants                        Act........................................
                      in common                                                                 (State)
                                                        UNIF TRF MIN ACT  -- .............Custodian (until age.........)
                                                                                 (Cust)
                                                                             ....................under Uniform Transfers
                                                                                    (Minor)
                                                                             to Minors Act..............................
                                                                                                   (State)
</Table>


    Additional abbreviations may also be used though not in the above list.


        FOR VALUE RECEIVED,___________________________hereby sell, assign and
transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
--------------------------------------

--------------------------------------


_______________________________________________________________________________
 (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

_______________________________________________________________________________

_______________________________________________________________________________

________________________________________________________________________ Shares
of the common stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint

______________________________________________________________________ Attorney
to transfer the said stock on the books of the within named Corporation
with full power of substitution in the premises.

Dated________________________


                                X_______________________________________________

                                X_______________________________________________
                                 THE SIGNATURE(S) TO THIS ASSIGNMENT MUST
                                 CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE
                       NOTICE:   FACE OF THE CERTIFICATE IN EVERY PARTICULAR,
                                 WITHOUT ALTERATION OR ENLARGEMENT OR ANY
                                 CHANGE WHATEVER.

Signature(s) Guaranteed




By___________________________________
THE SIGNATURE(S) SHOULD BE GUARANTEED
BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND
LOAN ASSOCIATIONS AND CREDIT UNIONS
WITH MEMBERSHIP IN AN APPROVED
SIGNATURE GUARANTEE MEDALLION PROGRAM),
PURSUANT TO S.E.C. RULE 17Ad-15.