REQUEST FOR PROPOSAL (RFP) FABRICATION OF METAL ORIGAMI … · origami optics, we extend the scope towards the development of a broadband RGB imaging camera using reflective 4-fold

REQUEST FOR PROPOSAL (RFP)

FABRICATION OF METAL ORIGAMI OPTICS

March 2019

SPACE APPLICATIONS CENTRE

INDIAN SPACE RESEARCH ORGANIZATION (ISRO)

AHMEDABAD – 380015

SAC-ISRO Page 1 of 35

Specifications for fabrication and testing of Origami Optics

The optical design of the multi-fold optics presented in this RFP is the proprietary work of Space Applications Center (ISRO) and shall not be used for any other

purpose except for preparation of the offer for fabrication.

CONTENTS

Section I Introduction 2

Section II Optical/mechanical/thermal requirements 5

Section III Specifications of primary and secondary mirror of

Origami optics

8

Section IV Final specifications of Origami optics 13

Section V Quality provisions 15

Section VI Test requirements 18

Section VII Documents required 21

Section VIII Deliverables and packaging 22

ANNEXUREs

ANNEXURE 1 Design / Sag Specifications 24

ANNEXURE 2 Coating / Black Paint On Optics - Specifications 25

ANNEXURE 3 Tolerance Specifications 27

ANNEXURE 4 Compliance Matrix for RFP 28

ANNEXURE 5 Mechanical Drawings 33





SECTION I

INTRODUCTION

This document gives the procurement specifications for fabrication and testing of

origami mirrors.

1.1 Scope

After successful implementation of proof-of-concept models of 8-fold and 4-fold

origami optics, we extend the scope towards the development of a broadband RGB

imaging camera using reflective 4-fold origami optics. In this document, the

procurement specifications for fabrication and testing of four-fold reflective Origami

mirrors for development of compact camera system are given. This document specifies

the details necessary for the design and testing of the optics.

The scope of the work includes:

Study of the specifications provided by SAC.

Procurement of RSA Aluminium blanks required for fabricating Origami mirrors.

Fabrication of primary and secondary reflective four-fold mirrors as per the

specifications given in this document

Demonstration of the performance of integrated assembly as per RFP specifications

Provide test data to SAC for dispatch clearance.

Packaging in a suitable container and shipment to SAC.

This document covers:

- A general description of reflective 4-fold Origami concept

- Optical specifications of the primary and secondary mirrors

- Tolerance specifications

- Qualification and optical testing requirements

- Deliverables

- Schedule

1.2 General description of Reflective Origami optics

Light enters through an annular aperture and with the help of concentric zone reflectors

and is focused at the image plane. Folding the light helps to achieve the desired focal

length without increasing the total optical track. To achieve desired performance,

aspheric surfaces are used which help to minimize aberrations and improve the design

tolerances with increase in depth of focus.





We have already implemented 4-fold metal origami based visible compact camera in

INS-1C mission. The proposed design has been configured on the same concept,

however the opto-mechanical design has been improved upon to minimize alignment

criticalities and the realization challenges that were faced in the previous design. This

four-fold camera design has better sensitivity and broader DOF than the previously

developed camera. The origami optics based camera system would be used for airborne

applications.

An air-spaced metal origami design with dovel-pin architecture has been proposed to

meet the desired specifications. The optics is designed with 4-fold bi-aspheric surfaces

having 138.85 mm focal length with an overall clear aperture diameter of 65 mm and

physical diameter of around 100mm. This obscured system has an effective aperture of

36.2 mm and f-number of 3.83 which covers ±3.6 degree field of view. Figure 1 shows

a typical optical schematic of the optics.

Figure 1: Typical 2-D (Representative) Optical Schematic of 4-fold metal origami

Detailed description for the development of the 4-fold reflective origami is given in the

following sections.





1.3 Applicable Documents

The latest revision of the following documents (including but not limited to) form a part

of specifications.

MIL-0-13830 - General specification covering the manufacture,

assembly and inspection of

MIL-M-13508C - Mirrors, glass, front surfaces aluminized for optical

elements

MIL-0-16898B - Optical elements packaging

MIL-I-45208 - Inspection requirements

1.4 Test Sequence

The test sequence as given in this document shall be adhered to. No other additions,

deletions and/or alterations to the test sequence and/or test specifications shall be done

without formal approval from SAC (ISRO).

1.5 Conditions and methods of test

The test conditions shall be in accordance with the specifications given in this

document. The test methods and the measurement procedures shall be worked out by

the supplier and submitted to SAC (ISRO) for approval. In any case, the supplier has

no right to implement any changes in the conditions or methods of the test without

formal approval from SAC (ISRO).

1.6 Supplier’s responsibility

The supplier shall be responsible for fabrication and testing of the 4-fold optics as per

the relevant specifications within the performance limits in the scheduled timeline. The

supplier shall also be responsible for delivering the product safely to the SAC. Any

lapse on the part of this would be the responsibility of the supplier.

1.7 Inspection rights

SAC / ISRO personnel shall participate/ monitor any of the tests and inspections

covered in this document. The supplier shall submit a schedule of activities including

the major milestones like fabrication, coating, testing of mirrors etc. If any test /

qualification is to be carried out at a place other them the manufacturer’s place, the

supplier shall make appropriate arrangements for participation of SAC / ISRO

personnel(s).





SECTION II

OPTICAL/MECHANICAL/THERMAL REQUIREMENTS

Total 02 sets of Origami mirrors (primary and secondary) are to be fabricated by the

vendor. Coating qualification shall be carried out at vendor’s premises. Based on SAC’s

feedback of coating qualification, supplier has to take up coating of optics.

2.1 The following are the optical, mechanical and thermal requirements to be met

for realization of the multi-fold Origami optics.

High quality RSA Aluminum shall be used for fabrication of primary and

secondary mirrors. The physical/ mechanical/ thermal properties of the material

batch to be used shall be sent to SAC.

Proper stress relieving shall be carried out on the blanks. This is to ensure that

there is no stress on the optics during diamond turning and testing.

The manufacturer shall ensure that holding of the components does not induce

any stresses and result in surface figure changes on removal of the component

from the fabrication/test fixtures. The manufacturer shall device suitable test

methods to demonstrate this aspect.

2.2 Optical Requirements

The material to be used for the fabrication of mirror should be as per the specifications

laid down in Section 3. The mirror shall meet the optical specifications with the

accuracies mentioned in Section 3. The optical surface of the mirror shall be free from

appearance of any cosmetic defects such as digs, scratches, pits, sleeks etc. as per MIL-

0-13830B. The permissible tolerance for such defects shall be as mentioned in RFP.

2.3 Mechanical Requirements

The mirror shall retain the surface profile after integration on its interface and after

mounting/ dismounting operations. When mounted, the mirror shall be perfectly

balanced. If required, mass of the mirror shall be reduced to a minimum through

scooping the material from the rear surface. Proper stress relieving methods shall be

followed during various stages of fabrication in order to minimize residual strain in the

mirror.

2.4 Scope of Work

Fabrication and testing of origami optics involves -

1. Study of optical design provided by SAC

2. Design of reflective coatings and providing response curves to SAC

3. Qualification of coating by vendor as per details specified in RFP





4. Fabrication of the primary and secondary mirrors

5. Coating of mirrors as per detailed specified in RFP

6. Black painting of blocking zones as per the details specified in RFP

7. Testing to ensure compliance to the specifications provided

8. Preparing test reports and providing to SAC for review and approval

9. Dispatch of optics to SAC

Fabrication and testing should be carried out to the best of engineering practices.

2.5 Sequence of Activities

1. The supplier shall study the optical design provided by SAC. Supplier shall prepare

the work plan for fabrication, coating and testing of the optics. The work plan shall

be submitted to SAC for approval.

2. SAC shall have the right to carry out minor modifications in the optical design

before the fabrication starts at no extra cost.

3. Procurement of RSA blanks, thermal paint etc. shall be initiated immediately on

receipt of purchase order.

All materials shall be procured in ONE lot and from the same batch.

4. Response plots (in excel sheet) for coating design is to be provided to SAC for

approval.

5. Coating trial runs to be made and testing to be carried out to ensure compliance to

appropriate MIL standards. Results of the coating runs to be provided to SAC along

with the coating witness samples.

6. Fabrication of optical components to be carried out (including black painting as

required).

7. Dimensions of all fabricated parts to be provided to SAC for approval. All

dimensions should be measured very accurately, preferably, in 3D CMM.

8. Measured data (Radius of curvature, SAG, conic constant etc.) of individual zones

to be provided to SAC for approval.

9. Optical testing to be carried out by vendor as per details provided in RFP (sections

IV & VI)

10. Review of all measured data by SAC and compliance to the specifications.

11. Prepare proper packaging before dispatching the optics to SAC in suitable

containers.

2.6 Coating

The supplier is responsible for the design and development of reflective coating.

Coating qualification shall be carried out by vendor following relevant MIL / ISO

standards. After coating qualification, deposition of coatings is to be carried out by





vendor as per the specifications provided in RFP. These coatings should maximize the

surface reflection in the spectral range of 350 - 900 nm. Average reflection should be

more than 88% for all surfaces over the spectral range.

2.7 Black Painting

The optics are to be black painted to reduce stray light. The paint to be used should be

vacuum compatible. Black painting details are provided in annexure 2.

Two of the available products are:

Supplier 1 MAP, Z.I Rue Ciement Ader, 09100 Pamiers, France

Items: PU1 black paint (1 kg pack) + PU1 thinner (1 litre pack) + Phosmap 11

primer (1 litre pack) + Phosmap 11 thinner (1 litre pack) + middle

plywood box.

Supplier 2 Lord Corporation, Chemical products, 2000 West Grandview Blvd,

P.O. Box 10038, Erie, PA 16514, United States.

Items Aero glaze Z306 Quart + Aero glaze 995824a quart.

The black paint should be applied according to the instructions of the selected

manufacturer.

5 samples of 75mm x 75mm x 3 mm thickness should be provided to SAC before

painting of mirrors. After getting clearance from SAC, painting of mirrors should be

started.





SECTION III

SPECIFICATIONS OF PRIMARY AND SECONDARY

MIRRORS OF ORIGAMI OPTICS

3.1 The specifications for the mirrors are given in Table 3.1 and 3.2 below.

Compliance to these specifications shall be demonstrated by the vendor. Test

method and setup to demonstrate this performance shall be realized by the

manufacturer. The chosen test configuration shall be mutually agreed upon.

It is to be ensured by the vendor that the specifications of the fabricated mirrors

shall meet the specifications mentioned in tables below within the specified

tolerance values. In case, the numbers do not match within the given tolerances,

the fabricator will have to re-fabricate the mirrors to meet the desired

specifications (in consultation with SAC). The final opto-mechanical

specifications shall be provided at the time of placement of the order.

TABLE 3.1

Please refer to Annexure 5 for drawing of these multi-fold optics

SPECIFICATIONS OF PRIMARY MIRROR

Please refer to Section 5 for drawing of primary mirror

S.No. PARAMETER SPECIFICATION

1. Material RSA-6061 T6 Aluminum

2. Surface profile As per the Surface Sag specifications / ZEMAX®

design given in Annexure-1 and drawing in Annexure

– 5

3. Shape of the Optics Circular

4. Physical Diameter 100 mm (refer annexure 5 for details)

5. Central Hole

Diameter

21 mm

6. Center thickness

Edge Thickness

5 mm (Open Tolerance) (TBD)

Actual Value to be supplied by fabricator

7. Clear Aperture > 67.00mm (Refer Annexure – 1, 2 and 5 for details)

8. Surface Profile Aspheric (Front)

Flat (Rear) (Refer Annexure 5)

9. Circularity at Edges Within 5 micron





10. Chamfering Sharp edges of the optics shall be chamfered to

around 0.3mm

11. Surface Figure

(Over the Full

Active Area)

Better than /8 Peak-to-Valley,

/40 RMS, → 632.8 nm (He-Ne)

12. Scratch/Dig 40/20 or better

13. Surface Roughness Less than 5 nm (< 3 nm shall be goal)

14. Coating Enhanced Al Coating / Silver Coating (mutually

agreed upon) with an additional Protective Overcoat

over the entire active area

15. Reflectance

(At 0 and 45 deg

Angles of Incidence)

Average ≥ 88%

(0.35 – 0.9 microns)

16. Coating Pinholes There should be no pinholes visible in the coating

when it is illuminated by a bright source of light /

backlit (As per relevant MIL standard)

17. Coated Area Refer Annexure 2 for details

18. Tolerance On

Coated Area (For

S.No.14.)

±50 microns

19. Coating Thickness

Uniformity

Better than 1 percent (desirable)

20. Rear Central Portion

For Light Exit

Refer Annexure 2 for details

21. Black Painted Area

Qualified black paint shall be used. Refer Annexure 2

and section 2.7 for details

22. Decenter vs.

mechanical center < ±3 microns

23. Collinearity of

optical and

mechanical axis

< 15 arc-sec

24. Rear Surface Please see Note 1 *

25. Mounting Pads Mounting pads shall be polished to optical flatness.

Rear surface of the pads should be parallel to the

front surface within ±20 µrad. The coplanarity of the

pads should be within ±10 µm. (Refer drawing)

(TBD*)

26. Weight of Mirror < 200 g

TBD*: Final specifications to be provided at the time of order placement. The

specifications may change by around 3-5% w.r.t the specified values.





* Note-1:

The primary mirror rear surface shall be diamond turned to 2 waves or better. Final

details of rear surface to be provided at time of order placement.

Figure 2. Rear surface of Primary Mirror

Suitable alignment references (two perpendicular lines of 100μ thickness or smaller)

shall be drawn on the rear surface (over the un-scooped areas) to define the transverse

axes (x & y axes) of the mirror. The apparent intersection of these two lines defines the

mechanical center. The length of the line shall be about 10 - 15 mm as shown in figure

above.

Note - 2: The fabricated optics shall withstand a storage temperature range from 10° C

to 50°C.

The mirror bonding location shall be as per Annexure 5.

TABLE 3.2

Please refer to Annexure 5 for drawing of these multi-fold optics

SPECIFICATIONS OF SECONDARY MIRROR

Please refer to Section 5 for drawing of primary mirror



2. Surface profile As per the Surface Sag specifications / ZEMAX®

design given in Annexure-1 and drawing in Annexure

– 5

3. Shape of the Optics Circular





4. Physical Diameter 100 mm mm (refer annexure 5 for details)

5. Central Hole

Diameter

None

6. Center thickness

Edge Thickness

5 -7 mm (Open Tolerance) (TBD)

Actual Value to be supplied by fabricator

7. Clear Aperture 65.00mm (Refer Annexure – 1, 2 and 5 for details)



9. Circularity at Edges Within 5 micron

10. Chamfering Sharp edges of the optics shall be chamfered to

around 0.5mm

11. Surface Figure

(Over the Full

Active Area)


/40 RMS, → 632.8 nm (He-Ne)


13. Surface Roughness Less than 5 nm (< 3 nm shall be goal)

14. Coating Enhanced Al Coating / Silver Coating (mutually

agreed upon) with an additional Protective Overcoat

over the entire active area

15. Reflectance

(At 0 and 45 deg

Angles of Incidence)

Average ≥ 88%

(0.35 – 0.9 microns)

16. Coating Pinholes There should be no pinholes visible in the coating

when it is illuminated by a bright source of light /

backlit (As per relevant MIL standard)

17. Coated Area Please refer Annexure 2

18. Tolerance On

Coated Area (For

S.No.14.)

±50 microns


Uniformity


20. Annular Aperture

For Light Input

Please refer Annexure 2

21. Black Painted Area

Qualified black paint shall be used. Please refer

Annexure 2 and section 2.7 for details

22. Decenter vs.


23. Collinearity of

optical and

mechanical axis

< 15 arc-sec






25. Mounting Pads Mounting pads shall be polished to optical flatness.

Rear surface of the pads should be parallel to the

front surface within ±20 µrad. The coplanarity of the

pads should be within ±10 µm. (Refer drawing)

(TBD*)


TBD*: Final specifications to be provided at the time of order placement. The

specifications may change by around 3-5% w.r.t the specified values.

* Note-3:

The secondary mirror rear surface shall be polished to 2 waves or better.

Figure 3. Rear surface of Secondary Mirror

Suitable alignment references (two perpendicular lines of 100μ thickness or smaller)

shall be drawn on the rear surface (over the un-scooped areas) to define the transverse

axes (x & y axes) of the mirror. The apparent intersection of these two lines defines the

mechanical center. The length of the line shall be about 10 - 15 mm as shown in figure

above.

The mirror bonding location shall be as per Annexure 5.





SECTION IV

FINAL SPECIFICATIONS OF ORIGAMI OPTICS

4.1 This section gives the optical specifications of Origami optics as integrated

assembly level after the completion of fabrication of primary and secondary mirrors

through diamond turning process, coating and black paint. These parameters will be

tested by the fabricator and/or at SAC. It is to be ensured that the specifications of the

completed optics (after optics turning, coating and black painting) meet the

specifications mentioned in table 3.1 within the specified tolerance values (Annexure

3).

In case, the numbers do not match within the given tolerances, the fabricator will have

to re-fabricate the optics to meet the desired specifications (in consultation with SAC).

The final specifications of the optics would be provided at the time of placement of the

purchase order.

The specifications are given in table 4.1 below. The ZEMAX listing is provided in

Annexure 1 for both the optics as mentioned in the RFP Document.

The mirrors have to be fabricated using single-point diamond turning machine on RSA

Aluminium material as per the specifications given in Section III, meeting the quality

and performance specifications as laid down in the RFP.

TABLE 4.1: SPECIFICATIONS FOR ORIGAMI OPTICS:

PERFORMANCE PARAMETERS


1. Effective Focal Length 138.85 mm ± 1 mm

2. F/Number (Effective) 3.83

3. Field Of View ± 3.6°

4. Image format (diagonal) 17.5 mm

5. Primary to secondary mirror separation (mm)

(at edge of mirrors, 35mm semi-diametrically)

19.804 + 0.005

6. Secondary mirror (vertex) to image plane separation

(excluding detector window and band pass filter)

39.2478 ± 0.1

7. Design MTF, 45 lp/mm & 91 lp/mm 0.47 & 0.19

8. MTF (Realized, post fabrication)

%MTF at 45 1p/mm & 91 lp/mm 0.33 & 0.10

9.

Spectral range

(a) Central wavelength (nm) 550

(b) Half Power Band Width (nm) 300

10. Average transmission (%) (integrated assembly level) > 60%





Note: All the parameters during and/or after environmental test shall be measured at

a fixed distance from the flange chosen for initial measurement.

MTF measurement shall carried out in sagittal and tangential directions for all field

points as per following table

MTF measurement at various along and across track field angles

Across track field 3.60 1.80 0 -1.80 -3.60





SECTION V

QUALITY PROVISIONS

5. 1 Quality Assurance Requirements

Quality assurance requirements consist of

Space qualified material selection and qualification.

Ensuring that the optical components withstand a thermal environment from

−20°C to +60°C without affecting the performance when brought to ambient

The process qualification and control.

Qualification and acceptance test requirements.

Contamination control.

Vendor shall carry out qualification testing on witness samples for coating

qualification, described in the successive sub-sections of this documents. The

supplier/vendor should provide the reflection data for reflective coating on witness

samples in the form of EXCEL files after the design is completed, but before the actual

coating starts.

5.1.1 Material

The material used for fabrication of the optics shall be of space/military grade. The

substrate material used for fabrication of the optics shall be free from strain, internal

stresses and internal defects. The material from the same batch shall be used for

fabrication of all the components including witness samples.

Materials, which are nutrients for fungus, shall not be used. Materials used shall be of

low out gassing type with TML <1 %(preferably< 0.1%), and CVCM < 0.1 %

(preferably < 0.01 %) when subjected to 125 °C and less than 5x10-5 torr pressure for a

duration of 24 hrs (following ASTM E-595).

5.1.2 Processes The coating process involved in fabrication shall be qualified. In case the processes

have not already undergone the process qualification exercise, the same should be

qualified by the supplier before the start of actual components fabrication.

The witness samples for coating shall be fabricated from each production batch and

witness samples for coating shall be tested to confirm the suitability of the process

/materials used under the specified conditions.

5.1.3 Surface Quality

The optical surfaces shall have of cosmetic defects such as digs, scratches, pits, pin

holes and sleeks as per MIL-PRF-13830B. The permissible tolerance for scratches and

digs shall be 40-20.





5.1.4 In-process Quality Control Requirements

The manufacturer shall ensure the quality control for realizing a high quality product.

Manufacturer shall provide fabrication flow chart with Key Inspection Points (KIP).

The quality control shall also include, but not limited to, the following process

qualification details of coating, diamond turning etc.

A detailed quality control document shall cover:

- List of proposed materials with outgassing details and material vendors.

- Configuration control.

- Traceability includes batch number, fabrication lot number and component

identification.

- Cleanliness control.

- Process qualification details of coating.

- Non-conformance plan.

Non-conformance at any stage, which affects the quality and reliability of the product,

should be immediately reported to SAC and the required clearance shall be taken from

SAC. This data should be recorded and made available as and when required.

5. 2 Qualification Tests Requirements

Only qualified processes shall be adopted while fabricating the optics. The qualification

test level & test matrix for coating qualification is given in Table 5.1 & Table-5.2.

Minimum size of Witness Samples (WS) would be 1 inch. The methods and procedures

for measurement of parameters along with the test equipment, their calibration and

individual parameter limits should be communicated prior to qualification exercise.

Table 5.1: Test Matrix for qualification of coating on witness samples

Sr.

No. WS 1 WS 2 WS 3 WS 4

1 VI,SR VI,SR VI,SR VI,SR

2 Cold

Storage Humidity

Thermal

Cycle Thermal Shock

3 Hot Storage VI,SR VI,SR VI,SR

4 VI,SR Abrasion Adhesion -

5 - VI VI -





Table 5.2: Test Levels

Tests For Coating Qualification on

Witness

(AR & Reflective Coating)

For Origami Optics acceptance

Cold Storage Temp: - 20º ± 1º C;

Duration: 24 hrs.

Temp: - 20º ± 1º C;

Duration: 24 hrs.

Hot Storage Temp: 60º ± 1º C;

Duration: 24 hrs.

Temp: 60º ± 1º C;

Duration: 24 hrs.

Humidity R.H. 95%

Temp: + 50º C

Time: 24 hrs

-

Thermal Cycling Temp: - 20º to + 60º ± 1º C;

Dwell time: 2hrs ± 5 min

Transition rate: 3°C /min

No. of Cycles :10

Temp: 0º to + 50º ± 1º C;

Dwell time: 2hrs ± 5 min

Transition rate: 3°C /min

No. of Cycles :3

Thermal Shock Temp: - 20º to + 60º ± 1º C;

Dwell time: 5 min

No. of Cycles :200

-

Adhesion As per MIL 13830/ MIL-C-675 -

Abrasion As per MIL 13830/ MIL-C-675 -





SECTION VI

TEST REQUIREMENTS The test conditions shall be in conformance with the requirements of the specifications

given in this document. The test methods and measurement procedures shall be worked

out by the manufacturer and submitted to ISRO for approval. In no case shall the

manufacturer will have the right to implement any conditions or methods of the test

without the formal approval of SAC (ISRO).

Tests shall be conducted to verify the fabrication, workmanship and performance of the

mirrors. The manufacturer shall be responsible for the fabrication, performance of tests

and inspections as per the specifications.

SAC (ISRO) reserves the right to participate /monitor any of the tests and inspections

scheduled in this document. The manufacturer shall submit a schedule of activities to

SAC (ISRO). Prior to the commencement of tests, the manufacturer shall submit and

get approval from SAC (ISRO) about:

a) Method & procedure for conducting each test.

b) Accuracy and calibration status of the test equipment’s used.

c) Accept/Reject criteria in accordance with specification requirements.

Following tests shall be conducted on the mirrors post fabrication and coating:

1. Visual Inspection

2. Dimensional Stability

3. Surface profile including radius of curvature & eccentricity / conic constant

4. Physical and Clear Aperture dimensions

5. Circularity at edges of mirror

6. Thickness (Centre and Edge)

7. Mass of Mirror

8. Surface figure (Peak to Valley, RMS)

9. Reflectance

10. Surface quality (Scratch/dig)

11. All other parameters as mentioned in the document

The supplier shall submit the methods and procedures of all the tests for measurement

of parameters to meet the specifications. All the results at fabrication level and at post-

fabrication test level shall be provided to SAC in both hard and soft copies. The final

performance parameters with tolerances after achieving the required performance shall

be measured and provided.



The optical design of the multi-fold optics presented in this RFP is the proprietary work of Space Applications Center (ISRO) and shall not be used for any other purpose except for preparation of the offer for fabrication.

After fabrication of Origami Optics following environmental tests shall be carried out for acceptance of the Origami Optics.

Test levels are as per Table-2.

Table 6.2: Test Plan & Test Matrix

SR.

No Test

VI

(Note 1)

All

parameters of

tables 4.1

(Note – 2)

T MTF

(Note 3) COLL Remarks

1 Initial Bench Test at Ambient X X X X X

2 Storage Test

Post Cold

Post Hot

X

X

X

X

X

X

Note – 3

3 Post Thermal Cycling Test /

Final Bench Test at Ambient X X X X X Note – 3

Notes

Note 1 Visual inspection for holes, digs, bubbles, breakage, deformation, scratches, stresses, peeling of coatings, etc.

Note 2 For testing the parameters of the optics, optical equivalent of detector window, shall be placed near focal plane. The parameters that

shall be measured are: EFL, image format, spectral characteristic, transmission, MTF, mechanical parameters and weight.

Note 3 Parameters of optics shall be measured at ambient conditions after completion of the test.





ABBREVIATIONS:

VI = Visual Inspection

EFL = Equivalent Focal Length

T = Transmission

MTF = Modulation Transfer Function

COLL = Collinearity

6.1. Test Results

Properties of the materials (physical, chemical, optical and mechanical) used for

component fabrication and compliance certificates shall be supplied to SAC. The

supplier should provide details of the measurement set-ups as well as the measurement

conditions along with the appropriate data and digital data in Excel format of the

qualified/accepted component level measurements along with results of witness

samples (before & after each qualification test).

6.2. Rework criteria

If the supplier observes deviations from the specifications at any stage, the rework

criteria required to meet the specification, shall be provided by the supplier with proper

justification and analysis for approval of SAC.

6.3. Shelf life

The mirrors should meet the performance parameters in the standard lab conditions

without any severe degradation of performance. The manufacturer shall also specify

the storage conditions necessary to ensure the shelf life. Procedures to be adopted for

cleaning shall be specified.

6.4. Acceptance / Rejection Criteria

The components shall retain their environmental durability & mechanical integrity and

shall not visually show any sign of chipping, cracking of coating etc. The acceptance

of final product is based upon its compliance with all the specifications/requirements

laid down in the previous sections.





SECTION VII

DOCUMENTS REQUIRED

7.1 Document details

The documents shall include the following:

A. List of materials, their properties and processes used in the fabrication of the mirror

B. Test and Evaluation plan giving the test specifications and procedures, test facilities

and instruments proposed to be used during qualification and acceptance tests.

C. Fabrication plan, particularly addressing the procedure and method of realization

including processes to be used for coating annular zones

D. Procedure to measure Surface Sag on Aspheric Surfaces.

E. Detailed Test Procedure: The manufacturer shall suggest the detailed test procedure

and it shall be mutually agreed upon. It shall contain the following:

- Procedural steps right from the start to finish of the tests including handling,

inspection, pre- and post-functional tests along with the time schedule.

- Description of the test procedures, tests facilities, environmental conditions,

calibration and operational details.

- Expected test results with parameter-wise tolerances.

- Failure criteria, test termination criteria, etc.

F. Failure Analysis Reports (if any): The various failures, malfunctions and deviations,

observed during the tests along with analysis and corrective actions taken and their

effects etc. shall be clearly brought out in these reports.

G. Final Test Reports: A final report indicating the functional performance of optics

before and after the tests. The deviations observed during the tests and reports on

visual inspections giving consolidated data shall be made available.

H. Contamination Control: Detailed contamination control plan and monitoring details

with frequency shall be clearly brought out.

I. Handling and Storage Instructions: This shall contain the details for handling,

storage and details of coated surface protection, etc.

7.2 Non – Conformance Report

This shall contain any non-conformance to the specifications of components and

optics. These are to be immediately reported as soon as they are observed.





SECTION VIII

DELIVERABLES AND PACKAGING

8.1 Deliverables

Total Deliverables Two (02) sets of Primary and Secondary

Mirrors meeting the RFP specifications

(Total 4 nos. of mirrors)

Coating qualification samples 04 no of coating samples (untested) on

RSA Al material as per the RFP

Witness samples 04 pieces of 1” diameter with each

coating batch (with actual mirrors)

A single supplier has to provide all the components given in the sections above.

All documents required as per details given in section VII.

8.2 Packaging

Each mirror shall be packed in separate containers to protect against mechanical,

electrical and environmental damages. Each individual container shall have moisture

absorbing (desiccant) material inside. The category of parts, i.e., mirrors, witness

samples, test samples etc. shall be enclosed in the shipping package. Packaging and

handling should be as per the appropriate MIL standard. As the mirrors are coated,

surface shall be appropriately protected. Packaging shall be resistant to mechanical

shocks, humidity and dust. Contamination control protection shall be employed.

8.3 Delivery Schedule

The schedule for the supply of the origami optics shall be as follows

1. Contract Finalization Date T0

2. Delivery of coating samples T1 (T0 + 45) days

3. Delivery of Primary and Secondary T1 + 75 days

Mirrors (2 sets each) + witness samples

*To will be date of Order Placement and receipt of order by the vendor

*T1 will be date of go ahead after performance verification from SAC (Typically around 30days from date of receipt of coating samples / test optics)





8.4 Warranty: One Year Standard Warranty for optics

General Instructions

General Instructions, terms and conditions

1. The offer including discount if any, should be valid for at least 120 days from the

date of opening / due date of the tender.

Vendor should fill up compliance against each of the requirements mentioned in

Annexure 4 and all sections of RFP and submit along with the proposal. Providing

incomplete / no details on any point shall be treated as non-compliance.




ANNEXURE – 1

Design / Sag Specifications Zemax Listing

Entrance Pupil Diameter 138.85 mm (83% Obscured) Temperature 20°C Max. Radial Field ±3.6 degrees Wavelength (Primary) 550 nm

# Comment Type Radius Thickness Glass Diameter Conic Aspheric A4 Aspheric A6 Aspheric A8 Aspheric A10 Aspheric A12

OBJ STANDARD Infinity Infinity 0 0 - - - - -

STO STANDARD Infinity 0 65 0 - - - - -

2 Input Ap. STANDARD Infinity 24.00 65 0 - - - - -

3 Zone 1 EVENASPH -157.37 -21.93 MIRROR 67.5298 0.420 -3.337784E-07 9.297392E-11 2.549486E-13 -2.705333E-16 7.961655E-20

4 Zone 2 EVENASPH -225.37 21.90 MIRROR 50.3766 -3.000 -1.717485E-06 1.538563E-09 -8.155552E-13 -1.502545E-15 1.325639E-18

5 Zone 3 EVENASPH -238.62 -22.75 MIRROR 48.9174 -3.000 -2.287289E-06 1.639590E-09 -3.084376E-12 3.077681E-15 -1.204854E-18

6 Zone 4 EVENASPH -164.49 22.63 MIRROR 28.2545 -3.000 -4.585583E-06 -1.049624E-09 -1.489321E-11 4.003039E-14 -4.778912E-17

7 EVENASPH Infinity 0 21.0387 0 - - - - -

8 Back Working Margin STANDARD Infinity 10.867 21.0387 0 - - - - -

9 Filter 1.75 N-BK7 17.6934 0 - - - - -

10 2 17.3438 0 - - - - -

11 Detector Window STANDARD Infinity 0.55 D263TECO 16.7281

12 STANDARD Infinity 1.05 16.6190

IMA Image STANDARD Infinity 16.3105 0 - - - - -

**The final design specifications shall be provided at the time of order placement.





ANNEXURE – 2

COATING / BLACK PAINT ON MIRRORS: SPECIFICATIONS

Primary Mirror Surface:

The specifications for the primary mirror are given below:

Figure A.1: Coating details for Primary Mirror

Specifications for Primary Mirror

Table A.1: Specifications for Coating and Black-Paint for Primary Mirror

S.No. Start (Radial,

mm)

End (Radial,

mm)

Specifications

1. 0 11 Mirror opening

(Output from Optics)

2. 11 24.7 Coated Region

3. 24.7 25.5 Black Painted region

4. 25.5 34 Coated Region

5. 34 Edge of mirror Black Painted Region

* Final details shall be provided at the time of order placement





Secondary Mirror:

The specifications are given below for secondary mirror:

Figure A.2: Schematic showing the metal-coating and black-paint details for

secondary mirror surfaces

Specifications for Secondary Mirror

Table A.2: Specifications for Coating and Black-paint for secondary

mirror

S.No. Start (Radial,

mm)

End (Radial,

mm)

Specifications

1. 0 3.3 Black-Painted Region

2. 3.3 14.6 Coated Region

3. 14.6 16.5 Black-Painted Region

4. 16.5 25.5 Coated Region

5. 25.5 27 Black-Painted Region

6. 27 32.5 Input Aperture

(opening)

7. 32.5 Edge of mirror Black-Painted Region

* Final details shall be provided at the time of order placement





ANNEXURE – 3

TOLERANCE SPECIFICATIONS

FRONT AND REAR SURFACE:

S.NO. Parameter Specification

1. Thickness ± 3 µm

2. Radius of Curvature (Zones) ± 0.02 %

3. Decenter (Zones) ± 1 µm

4. Decenter (Rear w.r.t. Front Surface) ± 3 µm

5. Tilt (Zones) ± 0.2 arc-min

6. Tilt (Rear w.r.t. Front Surface) ± 0.2 arc-min

7. Tilt between optical and mechanical

axis

± 0.3 arc-min

8. Irregularity 0.5 fringe (→632 nm)





ANNEXURE – 4

Compliance matrix for RFP (To be filled by vendor with necessary remarks as applicable)

Section Details Compliance by

vendor with remarks

1 Introduction

1.1 Scope

1.2 General description of Reflective Origami Optics

1.3 Applicable documents

1.4 Test Sequence

1.5 Conditions and methods of tests

1.6 Supplier responsibility

1.7 Inspection rights

2 Optical / mechanical / thermal requirements

2.2 Optical requirements

2.3 Mechanical requirements

2.4 Scope of Work

2.5 Sequence of Activities

2.6 Coating

2.7 Black Painting

3 Specifications of primary and secondary mirrors of

origami optics

3.1 Table 3.1 – Specifications of Primary mirror

3.1 Table 3.2 – Specifications of Secondary mirror

4 Final Specifications of Origami Optics

4.1 Table 4.1 – Specifications for Origami Optics:

Performance parameters

5 Quality provisions

5.1 Quality Assurance requirements

5.2 Qualification tests requirements

6 Test Requirements

6.1 Test results

6.2 Rework criteria

6.3 Shelf life

6.4 Acceptance/ Rejection criteria

7.1 Documents required

7.2 Non-conformance report

8.1 Deliverables

8.2 Packaging





8.3 Delivery Schedule

8.4 Warranty

Table 3.1 – Specifications of primary mirror

S.No. PARAMETER SPECIFICATION Compliance

with

remarks


2. Surface profile As per the Surface Sag specifications /

ZEMAX® design given in Annexure-1

and drawing in Annexure – 5

3. Shape of the

Optics

Circular

4. Physical Diameter 100 mm (refer annexure 5 for details)

5. Central Hole

Diameter

21 mm

6. Center thickness

Edge Thickness

5 mm (Open Tolerance) (TBD)

Actual Value to be supplied by

fabricator

7. Clear Aperture > 67.00mm (Refer Annexure – 1, 2 and

5 for details)



9. Circularity at

Edges

Within 5 micron

10. Chamfering Sharp edges of the optics shall be

chamfered to around 0.3mm

11. Surface Figure

(Over the Full

Active Area)


/40 RMS, → 632.8 nm (He-Ne)


13. Surface

Roughness

Less than 5 nm (< 3 nm shall be goal)

14. Coating Enhanced Al Coating / Silver Coating

(mutually agreed upon) with an

additional Protective Overcoat over the

entire active area

15. Reflectance

(At 0 and 45 deg

Angles of

Incidence)

Average ≥ 88%

(0.35 – 0.9 microns)





16. Coating Pinholes There should be no pinholes visible in

the coating when it is illuminated by a

bright source of light / backlit (As per

relevant MIL standard)

17. Coated Area Refer Annexure 2 for details

18. Tolerance On

Coated Area (For

S.No.14.)

±50 microns


Uniformity


20. Rear Central

Portion For Light

Exit

Refer Annexure 2 for details

21. Black Painted

Area

Qualified black paint shall be used.

Refer Annexure 2 and section 2.7 for

details

22. Decenter vs.


23. Collinearity of

optical and

mechanical axis

< 15 arc-sec


25. Mounting Pads Mounting pads shall be polished to

optical flatness. Rear surface of the

pads should be parallel to the front

surface within ±20 µrad. The

coplanarity of the pads should be

within ±10 µm. (Refer drawing)

(TBD*)


TABLE 3.2: Specifications of secondary mirror


with

remarks


2. Surface profile As per the Surface Sag specifications /

ZEMAX® design given in Annexure-1

and drawing in Annexure – 5

3. Shape of the

Optics

Circular





4. Physical Diameter 100 mm mm (refer annexure 5 for

details)

5. Central Hole

Diameter

None

6. Center thickness

Edge Thickness

5 -7 mm (Open Tolerance) (TBD)

Actual Value to be supplied by

fabricator

7. Clear Aperture 65.00mm (Refer Annexure – 1, 2 and 5

for details)



9. Circularity at

Edges

Within 5 micron

10. Chamfering Sharp edges of the optics shall be

chamfered to around 0.5mm

11. Surface Figure

(Over the Full

Active Area)


/40 RMS, → 632.8 nm (He-Ne)


13. Surface

Roughness

Less than 5 nm (< 3 nm shall be goal)

14. Coating Enhanced Al Coating / Silver Coating

(mutually agreed upon) with an

additional Protective Overcoat over the

entire active area

15. Reflectance

(At 0 and 45 deg

Angles of

Incidence)

Average ≥ 88%

(0.35 – 0.9 microns)

16. Coating Pinholes There should be no pinholes visible in

the coating when it is illuminated by a

bright source of light / backlit (As per

relevant MIL standard)

17. Coated Area Please refer Annexure 2

18. Tolerance On

Coated Area (For

S.No.14.)

±50 microns


Uniformity


20. Annular Aperture

For Light Input

Please refer Annexure 2





21. Black Painted

Area

Qualified black paint shall be used.

Please refer Annexure 2 and section 2.7

for details

22. Decenter vs.


23. Collinearity of

optical and

mechanical axis

< 15 arc-sec


25. Mounting Pads Mounting pads shall be polished to

optical flatness. Rear surface of the

pads should be parallel to the front

surface within ±20 µrad. The

coplanarity of the pads should be

within ±10 µm. (Refer drawing)

(TBD*)


TABLE 4.1: Specifications For Origami Optics: Performance Parameters


with remarks

1. Effective Focal Length 138.85 mm ± 1 mm

2. F/Number (Effective) 3.83

3. Field Of View ± 3.6°

4. Image format (diagonal) 17.5 mm

5.

Primary to secondary mirror

separation (mm)

(at edge of mirrors, 35mm semi-

diametrically)

19.804 + 0.005

6. Secondary mirror (vertex) to image

plane separation (excluding detector

window and band pass filter)

39.2478 ± 0.1

7. Design MTF, 45 lp/mm & 91 lp/mm 0.47 & 0.19

8. MTF (Realized, post fabrication)

%MTF at 45 1p/mm & 91 lp/mm 0.33 & 0.10

9. Spectral range

(c) Central wavelength (nm) 550

(d) Half Power Band Width (nm) 300

10. Average transmission (%)

(integrated assembly level) > 60%




ANNEXURE – 5

Mechanical Drawings





