A look inside the Young Optics' Light Engine in LightCrafter

PedroGelabert

Other Parts Discussed in Thread: DLPC300, TPS63020

LightCrafter-aficionados,

Young Optics has done a great job in creating a compact light engine for LightCrafter. To explain the light engine, I have disassembled one of our units. I removed the cover on the top and bottom of the light engine. I also removed the Red LED heat sink and the Green and Blue LED heat sink. Note that any disassembly of the light engine voids the warranty on the LightCrafter system.

The following photo shows the top side of the light engine. The flex cables supply power to the LEDs. The DLP3000 DMD lies vertically on the top left hand side in front of the projection and focus lenses. The LEDs lie between the heat sink and light engine.

Each LED has an optical collimator to collect the wide beam of light from the LED and produce a narrower beam. This narrow beam of light passes through a set of dichroic mirrors that reflect a specific color of light while letting other colors of light pass through it. The dichroic mirrors recombine the different colors of light into one co-linear beam. The recombined light passes through a fly-eye and condenser lens that provides uniform light intensity. This uniform light intensity beam is directed towards the DLP3000 DMD.

Here are the paths of the red, green, and blue light:

When the DLP3000 pixels are in the on-position, light is reflected through the projection lens. When the DLP3000 pixels are in the off-position light is directed towards a light absorber barrier.

Here is a view of the dichroic mirrors in operation, see how only green and blue light are reflected from ambient light.

A final photo of the light engine with the LEDs removed. Copper sheets are used to dissipated the heat of the LEDs into the heat sinks. The top and smaller flex cable has a photo sensor next to the condenser and fly-eye lenses. This photo sensor is connected to DLPC300. The Green LED has a thermistor to measure the temperature. This thermistor is connected to a MSP430 ADC channel.

over 12 years ago

TieXue over 10 years ago

Intellectual 495 points

does this engine case made by plastic or iron?

Thanks

Adam Kunzman over 10 years ago in reply to TieXue

Intellectual 750 points

TiuXue,

The case is a hard plastic.

TieXue over 10 years ago in reply to Adam Kunzman

Intellectual 495 points

Thanks Adam :)

Michael Ciuffo over 10 years ago

Prodigy 20 points

I'm curious about the specific angles involved in the mirror that reflects the light towards the DMD. From the images you've posted, it looks like the mirror sits between the DMD and the output optics blocking light from leaving the projector. Can you provide another image that demonstrates how the light moves around the mirror?

PedroGelabert over 10 years ago in reply to Michael Ciuffo

TI__Expert 6995 points

Michael,

The mirror is not on the path of the light exiting the DMD and entering the projection optics. This image might help.

Michael Ciuffo over 10 years ago in reply to PedroGelabert

Prodigy 20 points

Thank you!

Sam Van der Jeught over 10 years ago in reply to Michael Ciuffo

Prodigy 120 points

Dear Pedro,

If I wanted to replace one of the R,G,B LED's with a white one, how should I go about this? Are there LED models you would suggests for this operation?

Thanks!

Sam

Sanjeev over 10 years ago in reply to Sam Van der Jeught

TI__Mastermind 30875 points

Hi Sam,

Refer to the LED discussion here http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/850/t/220035.aspx

Regards,

Sanjeev

ZULFIQAR ALI over 9 years ago in reply to Sanjeev

Prodigy 60 points

Hi Sanjeev,

I am curious to know the projection optics when the light is coming from DMD. How many lenses have been used in the projection optics and what are the types of those lenses?

Also it will be better if i can know the distances between DMD and these projection lenses.

I hope this pics will explain what i want

ELD over 9 years ago in reply to ZULFIQAR ALI

TI__Intellectual 2175 points

Hello Zulfiqar,

We do not have the precise measurement information and lens composition you requested. Young Optics owns that information. Are you needing a reference design for the DLP3000 or are you wanting the specific design used by Young Optics?

Regards,

Eric

ZULFIQAR ALI over 9 years ago in reply to ELD

Prodigy 60 points

Hello Eric,
Thanks a lot for your feedback.
I want specific information regarding the the projected lens that have been used for the projection of the image coming out from DMD ,most importantly how many lens have been used . And if i can know the dimensions than it will be very good because i am modeling the process and i want that distances from DMD to the Projected lens and than from projected lens to Screen where i am projecting it. I have measured the distance upto orifice of the DLP but can not go further .

ZULFIQAR ALI over 9 years ago in reply to ZULFIQAR ALI

Prodigy 60 points

Dear TI team,
I am still waiting for the answers regarding my query.

Thanks

Regards

Zulfiqar

ELD over 9 years ago in reply to ZULFIQAR ALI

TI__Intellectual 2175 points

Hello Zulfiqar,

Thank you for following up on my question. Unfortunately, we do not have the information you are requesting.

Regards,

Eric

PedroGelabert over 9 years ago

TI__Expert 6995 points

The LightCrafter LED Driver is a modified version of the LED driver shown in section 3 of this application note: Different methods to Drive LEDs Using TPS630xx Buck-Boost Converters

Our modification adds PWM control to the feedback path of the DC-DC converter. A rough circuit is shown by this figure:

This circuit involves controlling several factors to optimize the operation of the LED at a given voltage. Note that in LightCrafter,

the LED_PWM voltage (Vpwm) swings up to 3.3V and has a range of 1024 steps.
Bias = 16V.
Vfb = 0.5V for TPS63020

With this is mind, the Vadj voltage can be calculated as:

Vadj = Vfb + [(Vpwm * PWM /1024) - Vfb] * R2pwm / (R1pwm + R2pwm)

Current through R3pwm, I3 is given by:

I3 = (Vadj - Vfb) / R2pwm + (Vbias - Vfb ) / Rbias - Vfb / R2 + (Vout - Vfb) / R1

Then the LED current, Iled is given by:

Iled =(Vfb - I3 * R3pwm) / Rilim - I3

With these equations, you can set a max, nom, and min options and explore the range of current though the LED assuming a min PWM value of 1024 and a max PWM value of 1.

user3899930 over 9 years ago

Prodigy 10 points

Hi,Pedro
The Young is eProtech?One company?
An other question,Would you recommen a company who can provide precision optical engine?I want to build a project of Vision measurement.

Keeyoung Han over 8 years ago

Prodigy 70 points

Hi PedroGelabert,

I'd like to reduce throw ratio to about 0.6 for wide angle projection.

I know LightCrafter SR1(http://ekb.co.il/pages/products/e4500sr1.php), but this is more expensive than LightCrafter...

Could I do this?

Thanks.

Paul Goedeke over 8 years ago in reply to Keeyoung Han

TI__Mastermind 30600 points

Keeyoung Han,

TI does not provide any guidance on how to modify the Lightcrafter optics to achieve specific specifications. If you would like to modify the optics, please do but be aware that your warranty will be voided.

It is unlikely that the current housing on the Lightcrafter will support much modification but if you have the optics expertise to make the correct changes and get it work with the current set-up, then by all means go ahead.

Otherwise, please consult with our design partners: e2e.ti.com/.../3404.design-network-partners

Thanks,
Paul

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A look inside the Young Optics' Light Engine in LightCrafter