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                                                                  EXHIBIT 10.23

                      FOURTH AMENDMENT TO LICENSE AGREEMENT
                      -------------------------------------

         THIS FOURTH AMENDMENT TO LICENSE AGREEMENT (the "Fourth Amendment") is
made and entered into as of the 14th day of September, 1998, by and between
IRVINE SENSORS CORPORATION, a Delaware corporation (the "Company"), and ADVANCED
TECHNOLOGY PRODUCTS, LLC, a California limited liability company ("ATP"), with
reference to the following facts:

         A.       The Company and ATP have previously executed a License
                  Agreement dated July 30, 1997 (the "License Agreement") and
                  First, Second and Third Amendments to the Agreement.

         B.       Pursuant to the Third Amendment to the Agreement investors in
                  ATP were offered the opportunity, through their election of
                  Royalty Program "C," to receive a prepayment of their royalty
                  interest in the E-Film product in the form of shares of common
                  stock of Imagek, Inc., a Delaware corporation and subsidiary
                  of the Company ("IMAGEK"), at the exchange rate of 8,500
                  shares of the common stock of IMAGEK, for every $10,000
                  invested in ATP. Pursuant to this exchange offer, ATP, has now
                  received elections representing $1,435,000 of the $1,635,000
                  invested in ATP, entitling these investors to the receipt of
                  1,221,875 shares of common stock of IMAGEK. One investor,
                  representing $200,000 of invested capital in ATP, has elected
                  to remain as a Royalty Program "B" investor and will continue
                  to receive royalty payments for the E-FILM and VIP 20 products
                  as provided for in Section 4.1b of the amended License
                  Agreement. All other investors' rights to receive royalty
                  payments from E-Film sales is hereby terminated as of the
                  closing date of the exchange of their E-Film royalty rights
                  for shares of common stock of IMAGEK.

         C.       The Company and IMAGEK have entered into an Assignment
                  Agreement of even date herewith (the "Assignment Agreement"),
                  wherein the Company has agreed to cause ATP to assign to
                  IMAGEK, all rights, title, and interest in and to the ATPL
                  Technology (as defined in the Assignment Agreement), and ATP
                  has agreed to grant said assignment.

         D.       Upon ATP's execution of an agreement entitled "Assignment of
                  ATPL Technology," IMAGEK will issue 1,221,875 restricted
                  shares of authorized IMAGEK Common Stock to ATP and shall pay
                  to ATP a reduced royalty as provided in this Fourth Amendment.
                  The IMAGEK stock and royalty payments shall be redistributed
                  to investors in ATP in accordance with the provisions of this
                  Fourth Amendment and the Assignment of ATPL Technology.

         E.       The Company and ATP have mutually consented to the termination
                  of the License Agreement and all amendments thereto upon ATP's
                  execution of the Assignment of ATPL Technology.

         NOW, THEREFORE, for the good and valuable consideration, the receipt
         and adequacy of which are hereby acknowledged, the parties hereto do
         hereby agree as follows:

         1.       Section 4.1 of the License Agreement is amended as follows:

                  a. Section 4.1a (Royalty Program "A") is hereby deleted in its
         entirety.

                  b. Section 4.1b (Royalty Program "B") shall remain as stated
         in the Third Amendment to the License Agreement. The parties
         acknowledge that for purposes of calculating royalties due under this
         section that the amount of capital invested by ATP in the Company is
         deemed to be $200,000.

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                  c. Section 4.1c (Royalty Program "C") shall remain as stated
         in the Third Amendment to the License Agreement. The parties
         acknowledge that all investors in this classification have elected to
         have their E-Film royalty rights converted to shares of common stock of
         IMAGEK, but shall continue to be entitled to receive royalty payments
         for VIP 20 sales as stated in the Third Amendment to the License
         Agreement.

         2. Section 5.2 of the Agreement, regarding the right of ATP investors
         to elect to have the Company redeem their interest in ATP with shares
         of restricted common stock of the Company, is amended to provide that
         those Royalty Program "A" investors who have elected Royalty Program
         "C" shall retain 50% of their share redemption rights as granted in
         Section 5.2 of the Licensing Agreement.

         3. ATP agrees to assign all right, title, and interest in and to the
         ATPL Technology to IMAGEK in an agreement which is in substantially the
         same form as the agreement attached as Exhibit "A" to the Assignment
         Agreement (the "Assignment of ATPL Technology").

         4. The company and ATP agree that the License Agreement and all
         amendments thereto shall terminate upon ATP's execution of the
         Assignment of ATPL Technology.

         IN WITNESS WHEREOF, the parties hereto have caused this Fourth
Amendment to the Agreement to be signed as of the date first above written.

                                        IRIVINE SENSORS CORPORATION
                                        a Delaware corporation

         Dated:  9/14/98                By:    /S/ JAMES D. EVERT
               ---------                     -----------------------
                                             James D. Evert, President

                                         ADVANCED TECHNOLOGY PRODUCTS, LLC
                                         a California limited liability company

         Dated:   9-14-98                By:  /S/  JOHN C. CARSON
               ----------                    -----------------------
                                            John C. Carson, Managing Member

                                       2<PAGE>
                                                                  EXHIBIT 10.24

                                     IMAGEK
                         "Going Digital is a Snap"(TM)

                                                                  March 26, 1999

Mr. Itzhak Sapir
19 Hickory
Irvine, California 92614

         This letter will confirm our discussions about an adjustment in your
royalty payments and stock option compensation at Imagek. Imagek will continue
its obligations under the License Agreement between you and Irvine Sensors
Corporation, effective October 7, 1997, with the adjustment that the royalty
payments will comprise 1.5% of all e-film sales, and that Imagek will grant you
options to purchase 275,000 shares of Imagek stock, exercisable immediately, at
a price of $1.00 per share. This agreement will be memorialized in an amendment
to the License Agreement to be signed by you and the company.

         You will continue to serve as the Senior Engineer - Mechanical at the
company. In recognition of your continuing service to the company, Imagek will
grant you options to purchase an additional 25,000 shares of Common Stock, at an
exercise price of $1.00 per share. These options shall vest and be exercisable
on September 30, 1999. In addition, as an employee of the company you will be
eligible to receive additional options at the board's discretion, and
participate in bonus plans, if any.

         Until a separate supplemental compensation package is established by
Imagek, you will continue to receive the standard package of Irvine Sensors
Corporation employee benefits, which includes paid group medical, dental, and
life insurance, as outlined in your employment offer letter of September 23,
1998.

         Itzhak, we are very pleased to have you part of the Imagek team and
believe that this will be a mutually rewarding and beneficial relationship.

                                             Best regards,

                                             /s/ Robert Webber

                                             Robert Webber
                                             President & CEO

AGREED:

/s/ I. Sapir
-----------------------------
Itzhak Sapir<PAGE>

                                                                  EXHIBIT 10.25

                         EQUIPMENT SUBLEASE AGREEMENT #1
                         -------------------------------

         This Equipment Sublease Agreement (the "Agreement") is made and entered
into as of the Effective Date, by and between Quest Manufacturing, Inc.
("Quest") and Silicon Film, Inc. ("SF"). Quest and SF are sometimes referred to
singularly as a "Party" or collectively as the "Parties."

                                    RECITALS
                                    --------

         WHEREAS, Quest desires to sublease certain equipment, as described in
the attached EXHIBIT A, to SF;

         WHEREAS, SF will compensate Quest according to the terms and conditions
set forth in this Agreement.

                              TERMS AND CONDITIONS
                              --------------------

         NOW, THEREFORE, in consideration of the mutual obligations and promises
and additional consideration set forth herein, the Parties agree as follows:

1. AGREEMENT TO LEASE. Quest hereby leases to SF, and SF leases and rents from
Quest, the computer hardware, peripherals and software more fully described on
the attached EXHIBIT A (the "Equipment"). The Equipment shall include all
replacement parts, repairs, upgrades, additions, modifications and accessories.

2. TERM. Subject to the conditions provided for below, this Agreement, and the
lease of the Equipment, shall be for a term of 20 months, the first scheduled
payment, after any payments done at the signing of this agreement, will commence
on March 1, 2004, with a last payment due on October 1, 2005.

3. LEASE PAYMENT. At the signing of this Agreement SF agrees to pay Quest
document fees in the amount of $0. At the signing of this Agreement SF agrees to
pay Quest first and last payments in the amount of $0. During the Term of this
Agreement, SF agrees to pay on the 1st day of each calendar month, a lease
payment for the Equipment in the amount of $346.90 (the "Rental Payment).

4. TERMINATION. This Agreement shall terminate upon any one of the following
Events of Termination:

                  (a) EXPIRATION. This Agreement may terminate on account of
expiration of the Term.

                  (b) FAILURE TO PAY. If SF remains more than sixty (60) days
behind payment for any monthly Rental Payment, Quest may terminate the Agreement
immediately and without further notice or opportunity to cure. In such event, SF
agrees to deliver the Equipment in good condition to Quest and agrees to pay any
accrued and unpaid Rental Payments due under the full term of the lease,
Interest, and Late Fees, etc. charged to Quest by the financial institution to
which Quest has signed the primary lease for the equipment.

                                  Page 1 of 4
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                  (c) BANKRUPTCY. Either Party may terminate this Agreement
immediately upon notice to the other if the other Party becomes insolvent or
bankrupt, assigns all or a substantial part of its business or assets for the
benefit of creditors, permits the appointment of a receiver for its business or
assets, becomes subject to any legal proceeding relating to insolvency,
reorganization or the protection of creditors' rights or otherwise ceases to
conduct business in the normal course.

5. TITLE TO THE EQUIPMENT. Quest shall at all times retain title to the
Equipment. All documents of title and evidence of delivery shall be retained by
Quest. SF agrees not to remove any lettering or insignia on the Equipment which
may denote title in Quest. Quest may cause this Agreement to be filed and
recorded, or cause financing statements to be filed as permitted by law. SF
shall protect and defend Quest's title, at all times keeping the Equipment free
from any legal process and/or encumbrances whatsoever, including, but not
limited to, liens, attachments, levies and executions, and shall give Quest
written notice as soon as practicable of any such lien. SF agrees to indemnify
Quest for any loss caused by the failure of SF to take action as provided
herein.

6. INSTALLATION. Quest agrees to install the Equipment at its own expense upon
SF's premises by itself or a third-party. Quest shall not be responsible for any
loss, damage or injury arising out of such installation or use of the Equipment.

7. MAINTENANCE. SF agrees that it will, at its own cost and expense, maintain
the Equipment in good operating condition, and protect the same from
deterioration, normal wear and tear excepted. SF covenants to use the Equipment
only in furtherance of its business operations and will not modify or alter the
Equipment without the written consent of Quest, which shall not be unreasonably
withheld.

8. INSURANCE. Quest agrees to name SF as an additional insured under its
policies of insurance covering property damage to the Equipment. Quest agrees to
give SF at least thirty (30) days' notice prior to cancellation of any such
insurance policies.

9. DISCLAIMER OF REPRESENTATIONS AND WARRANTIES. SF agrees and acknowledges that
Quest makes no warranty of any nature whatsoever, whether express or implied, as
to the suitability of the Equipment for SF's business use. QUEST HEREBY
DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR PARTICULAR
PURPOSE AND SF ACKNOWLEDGES THE REASONABLENESS OF THIS DISCLAIMER.

10. DECLARATION OF INSOLVENCY. Upon any event of termination set forth in
Section 4(c), Quest shall have the right to enter the premises of SF (or
anywhere the Equipment may be found) and take possession of the same and remove
the same, upon which all rights of SF will terminate absolutely. Quest's right
to possession under this Section 10 shall inure to its benefit without demand or
legal process and without being guilty of trespass or conversion.

11. DELIVERY UPON TERMINATION. Upon termination or expiration of this Agreement,
SF shall deliver with all expenses prepaid to Quest the Equipment to an address
designated by Quest complete and in good condition, normal wear and tear
excepted.

                                  Page 2 of 4
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12. MISCELLANEOUS.

                  (a) GOVERNING LAW. This Agreement will be governed by the
internal law of the State of Illinois, without regard to choice of law rules.
Exclusive venue for any dispute arising out of this Agreement, or the Parties'
performance under this Agreement, shall lie in the Circuit Court of DuPage
County, Illinois, and each Party acknowledges that this is a reasonable choice
of forum.

                  (b) AMENDMENTS AND WAIVER. The provisions of this Agreement
may be amended or waived only with the prior written consent of an authorized
representative of each Party.

                  (c) COMPLETE AGREEMENT. This Agreement embodies the complete
agreement and understanding among the Parties and supersedes and preempts any
prior understandings, agreements or representations by or among the Parties,
written or oral, which may have related to the subject matter hereof in any way.

                  (d) COUNTERPARTS. This Agreement may be executed in several
counterparts, all of which taken together shall constitute one single agreement
between the Parties.

                  (e) SUCCESSORS AND ASSIGNS. This Agreement is intended to bind
and inure to the benefit of and be enforceable by the Parties and their
respective representatives, contractors, successors and assigns.

                  (f) FURTHER ASSURANCES. The Parties agree to cooperate fully
and to execute any and all supplementary documents and to take all additional
actions that may be necessary or appropriate to give full force and effect to
the terms and intent of this Agreement.

                  (g) ATTORNEYS' FEES. In any action or dispute arising out of
this Agreement, the prevailing Party shall be entitled to recover from the other
Party its reasonable attorneys' fees, costs and expert witness fees, in addition
to any other rights and remedies available to it at law or in equity.

                  (h) EFFECTIVE DATE. The effective date of this Agreement shall
be February 18, 2004 (the "Effective Date").

                                  Page 3 of 4
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         IN WITNESS WHEREOF, the Parties have executed the foregoing Agreement
on and as of the Effective Date.

Quest Manufacturing, Inc.                      Silicon Film Technologies, Inc.

By:   /S/ JOHN A. LICHTER                      By:   /S/ SEBASTIEN C. DUFORT
    ----------------------------                   ----------------------------

Name: John A. Lichter                          Name: Sebastien C. DuFort

Its:  President & CEO                          Its:  President

Date:   3/18/04                                Date:   3/18/04
      -----------                                    -----------

Reference Quest Dell Lease 001-5998055-002

                                  Page 4 of 4

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                                   EXHIBIT A
                                   ---------

                   Lease Agreement dated as of October 3, 2002
                      between Quest Manufacturing and Dell
                             Financial Services L.P.

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