Thermo-Radiant Viewing Ocular

LUMITRONICS

THERMO-RADIANT VIEWING OCULAR

-Mode one: Temperature-correlated coloration of hot, glowing objects.

-Mode two: Monochromatic, isothermal, contour structure.

-Real-time analog. Not a camera/display. No pixel structure.

-Broad band visible 400 - 660 nm, over 20 deg FOV.

-For cameras, eyes & processing systems.

-Reveals thermal properties of hot, glowing objects

Head mounted binocular application

with two TRVOs.

Another option is attachment to a camera.

		Images from photographing through the TRVO.

	Left: The ocular creates color-coding for a range of effective black-body temperatures in hot glowing object. Right> Adding a narrow band filter and further adjustment promotes imaging of isothermal contours.

THERMO-RADIANT VIEWING OCULAR (TRVO) PROTOTYPE

WHAT IT IS: The TRVO is a small, analog, electro-optic, broad-band ocular for thermal viewing of hot, glowing objects with or without external illumination. It is not a camera/display unit, containing no resolution-limiting pixel structure. In real-time it relays attenuated image light directly from glowing objects but transmits the broad visual spectrum of hottest regions differently than less hot regions. One mode emulates a temperature-dependent color filter, resembling a pseudo-color image. Nearby objects below the temperature threshold have no filtering difference among them. A second mode uses a narrow band filter and other adjustments; it cycles between transmittance and attenuation multiple times across thermal gradients. The result is an isothermal contour map. Photosensitivity of the internal Photosensitive Optical Modulator (POM) is from 660 to > 760 nm. The internal, electrically powered POM can be made to reduce transmittance at high intensities, yet it is patently different from the SGRO. Since the POM is nonlinear to deep red intensity, there is a temperature/radiance modulation threshold.

Aside from being wholly analog and not a digital camera/display system, the TRVO is less sensitive than thermal imaging cameras, but better at temperature indication of extremely hot objects while simultaneously displaying the visible wavelength surroundings (equivalent to sensor fusion). Photographs shown are actually for a 120 V, 120 W spot lamp with a filament color temperature of approximately 2800 deg K, but has less intense deep red emission from the surface. Coloration for an object like molten steel or the inside of a furnace (everywhere emitting directly) indicates a real temperature.

The TRVO can be attached to a helmet or held to the eye (or camera). When adjusted for moderate color/fringe distribution, gentle movement of the head/ocular unit will cause little or no streak or flashing due to POM latency. For high sensitivity and dense fringing, movements should be slow to reduce latency. Two TRVOs can be used in a binocular arrangement, of course, but also a non-stereographic configuration seen with both eyes can be used with only one TRVO.

DISCUSSING APPLICATIONS: Applications exist in industry, materials arts, photography; any activities with hot, glowing objects. You are invited to inquire or discuss applications, markets and required volume with us. Influence specification development so your application is covered.

TENTATIVE PROTOTYPE SPECIFICATIONS⁽¹⁾

Transmittance of low level light (T_low):	14% (goal 20%, 40% for two POMs)
Visual band	400 - 660 nm
Photosensitive band (PSB)	670 to >760 nm
Sensitivity⁽²⁾ for PSB at 1kHz:	<190mW/cm².⁽³⁾ from 0.012 sterad source
Temperature range (bb equivalent)	1310 - 2100 deg K⁽⁴⁾ much higher with filters
Temperature resolution (bb equivalent)	132 deg K⁽⁴⁾ avg for 5 to 6 intra-color intervals
FOV:	25 deg
f/stop #	4.2
Temporal attenuation response:	10 ms to 50 ms sum of risetime and decay.⁽⁵⁾
Image Resolution, center field:	87 lp/deg monchrom, 31 lp/deg widbnd color
POM modulation resolution	36lp/deg
Size/weight	6.4 cm x 9 cm x 10.2 cm, 0.34 kg (12 oz.)
Power Required:	3 - 8 V for 100Hz - 2kHz ac square wave <0.17 mA (^@ 1kHz)

1) Values for prototype are not limits for more fully developed TRVO. Exact values not assured; may change.

2) Incident PSB Intensity for 90% max.color at 1 kHz power.

3) Far less intensity required for lower voltage (® 3v) and/or lower pwr frequencies, but response time increases.

4) From preliminary meas. 1kHz, 4.5 V power. Lower T, DT obtained with lower f or V; higher with filter over input.

5) Fastest response time for high voltages, lowest at lower voltages. Rise ~ 10% to 90%, decay 90% to 10%. Sum of rise and fall is the best response indicator. Specific parameter adjustments determine whether rise or fall time is greater.