UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 6)*

RAE Systems Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

75061P 10 2

(CUSIP Number)


Robert I. Chen		Robert T. Ishii
c/o RAE Systems, Inc.		Wilson Sonsini Goodrich & Rosati,
3775 North First Street		Professional Corporation
San Jose, California 95134		One Market Street, Spear Tower Suite 3300
		San Francisco, California 94105
(408) 952-8200		(650) 947-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

May 25, 2011

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).


1		NAMES OF REPORTING PERSONS: Robert I. Chen
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: United States of America


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 15,834,942
		9 SOLE DISPOSITIVE POWER: 270,833
		10 SHARED DISPOSITIVE POWER: 15,564,109


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 15,834,942*
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 26.6%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO

*	Includes options to purchase 270,833 shares of common stock of issuer exercisable within 60 days.


1		NAMES OF REPORTING PERSONS: Lien Q. Chen
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: United States of America


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 15,564,109
		9 SOLE DISPOSITIVE POWER: 0
		10 SHARED DISPOSITIVE POWER: 15,564,109


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 15,564,109
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 26.2%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO


1		NAMES OF REPORTING PERSONS: Chen Revocable Trust DTD 5/8/2001
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: California


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 15,382,849
		9 SOLE DISPOSITIVE POWER: 0
		10 SHARED DISPOSITIVE POWER: 15,382,849


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 25.8%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO


1		NAMES OF REPORTING PERSONS: Chen Family Foundation
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: California


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 181,260
		9 SOLE DISPOSITIVE POWER: 0
		10 SHARED DISPOSITIVE POWER: 181,260


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 181,260
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 0.3%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO


1		NAMES OF REPORTING PERSONS: Peter Hsi
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: United States of America


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 2,757,998
		9 SOLE DISPOSITIVE POWER: 66,666
		10 SHARED DISPOSITIVE POWER: 2,691,332


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 2,757,998*
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 4.6%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO

*	Includes options to purchase 66,666 shares of common stock of issuer exercisable within 60 days.


1		NAMES OF REPORTING PERSONS: Sandy Hsi
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: United States of America


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 2,691,332
		9 SOLE DISPOSITIVE POWER: 0
		10 SHARED DISPOSITIVE POWER: 2,691,332


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 2,691,332
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 4.5%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO


1		NAMES OF REPORTING PERSONS: Hsi Family Trust
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS): (a) ¨ (b) x
3		SEC USE ONLY:
4		SOURCE OF FUNDS (SEE INSTRUCTIONS): OO
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e): ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION: California


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7 SOLE VOTING POWER: 0
		8 SHARED VOTING POWER: 2,691,332
		9 SOLE DISPOSITIVE POWER: 0
		10 SHARED DISPOSITIVE POWER: 2,691,332


11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 2,691,332
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS): x (See Item 6)
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 4.5%
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS): OO

This Amendment No. 6 (this “Amendment No. 6”) to the statement on Schedule 13D, filed with the Securities and Exchange Commission on behalf of the Reporting Persons relating to the Common Stock of RAE Systems, Inc., a Delaware corporation (“RAE”), on September 29, 2010, as amended and restated (the “Schedule 13D”) is being filed pursuant to Rule 13d-2 of the Securities Exchange Act, as amended, on behalf of the Reporting Persons to amend certain information set forth below to the items indicated. Unless otherwise stated herein, all capitalized terms used in this Amendment No. 6 shall have the same meaning as those set forth in the Schedule 13D.

Item 4.

Purpose of Transaction.

Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following:

On May 25, 2011, Purchaser, Merger Sub and RAE entered into Amendment No. 4 to the Merger Agreement (“Amendment No. 4 to the Merger Agreement”), pursuant to which, among other things, the Merger Consideration was increased to $2.25 per share, payable in cash, without interest. Purchaser and Merger Sub are each affiliates of Vector Capital IV, L.P., Vector Entrepreneur Fund III, L.P. and Vector Capital III, L.P. (together, “Vector”)

Concurrently with the execution of Amendment No. 4 to the Merger Agreement, the Chen Revocable Trust DTD 5/8/2001 (the “RLC Trust”) entered into an Amendment No. 2 to its Rollover Agreement (“Amendment No. 2 to the RLC Rollover Agreement”) which provides that the number of shares to be contributed by the RLC Trust for no consideration would increase to approximately 1.98 million shares, which have a value of approximately $4.45 million at $2.25 per share, which increase resulted from both the deal price increase and the price point beyond which upside is sacrificed moving from $1.75 per share down to $1.30 per share.

References to, and descriptions of Amendment No. 2 to the RLC Rollover Agreement throughout this statement are qualified in their entirety by reference to Amendment No. 2 to the RLC Rollover Agreement included as Exhibit 6 hereto and which is incorporated herein by reference.

Item 7.

Materials to be Filed as Exhibits.

Item 7 of the Schedule 13D is hereby amended to add the following exhibit:


6		Amendment No. 2, dated as of May 25, 2011, to Rollover Agreement, dated as of January 18, 2011, as amended, by and between RAE and RLC Trust

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.


Dated: May 25, 2011

CHEN REVOCABLE TRUST DTD 5/8/2001		CHEN FAMILY FOUNDATION

By:	/S/ ROBERT I. CHEN	By:	/S/ ROBERT I. CHEN
	Robert I. Chen		Robert I. Chen
	Trustee

By:	/S/ LIEN Q. CHEN	By:	/S/ LIEN Q. CHEN
	Lien Q. Chen		Lien Q. Chen
	Trustee

ROBERT I. CHEN		LIEN Q. CHEN

By:	/S/ ROBERT I. CHEN	By:	/S/ LIEN Q. CHEN

HSI FAMILY TRUST		PETER HSI

By:	/S/ PETER HSI	By:	/S/ PETER HSI
	Peter Hsi
	Trustee

		SANDY HSI

By:	/S/ SANDY HSI	By:	/S/ SANDY HSI
	Sandy Hsi
	Trustee

EXHIBIT INDEX


Exhibit No.		Title

6		Amendment No. 2, dated as of May 25, 2011, to Rollover Agreement, dated as of January 18, 2011, as amended, by and between RAE and RLC Trust

RAE SYSTEMS INC SC 13D/A