High Near-Infrared Sensitivity

The IMX585 is a Sony Starvis II processor that enables high sensitivity and high dynamic range (HDR). It also improves sensitivity in the near-infrared range by approximately 1.7 times* compared to the IMX485. The new camera miniCAM8 has a maximum quantum efficiency of 60% in the near-infrared band and 92% in the visible wavelength band.

*This data is officially provided by Sony: https://www.sony-semicon.com/cn/news/2021/2021062901.html

 

BSI

One benefit of the back-illuminated CMOS structure is improved full-well capacity. This is particularly helpful for sensors with small pixels. In a typical front-illuminated sensor, photons from the target entering the photosensitive layer of the sensor must first pass through the metal wiring that is embedded just above the photosensitive layer. The wiring structure reflects some of the photons and reduces the efficiency of the sensor.

In the back-illuminated sensor, the light is allowed to enter the photosensitive surface from the reverse side. In this case, the sensor’s embedded wiring structure is below the photosensitive layer. As a result, more incoming photons strike the photosensitive layer, and more electrons are generated and captured in the pixel well. This ratio of photon to electron production is called quantum efficiency. The higher the quantum efficiency, the more efficient the sensor is at converting photons to electrons, and hence the more sensitive the sensor is to capturing an image of something dim.

 

Zero Amplify Glow

miniCAM8 is also a zero amplifer glow camera.

 

Anti-Dew Technology

Based on almost 20-year cooled camera design experience, the QHY cooled camera has implemented the fully dew control solutions. The optic window has a built-in dew heater, and the chamber is protected from internal humidity condensation. An electric heating board for the chamber window can prevent the formation of dew, and the sensor itself is kept dry with our silicon gel tube socket design for control of humidity within the sensor chamber.

 

Cooling

In addition to dual-stage TE cooling, QHYCCD implements proprietary technology in hardware to control the dark current noise.

 

 

The native ADC of the IMX585 sensor is 12-bit. Compared to 16-bit, the 12-bit depth offers fewer bits, resulting in a relatively narrower dynamic range, which may lead to issues such as insufficient color gradation and potential information loss. During the product development of miniCAM8, QHYCCD merged high and low gain to extend the data to 16-bit. However, since this 16-bit depth is not native, a sudden shift in linearity might occur, affecting the smooth transition in images. To address this, QHYCCD developed the "Linearity HDR” mode, which uses an algorithm-based approach to correct image linearity through software, ensuring smoother transitions and richer color representation.

In the "Linearity HDR” mode, the full well is 46 ke-, while the read noise is only 1.0e-; the dynamic range reaches up to 46,300:1, equivalent to 93 dB or 15.5 stops.

 

miniCAM8 Deep sky filters: 

The astronomical filters included with the miniCAM8 deepsky combos are custom-designed to match the specific characteristics of the cameras. The size is 19 mm * 12 mm * 1.1 mm. The LRGB and SHO narrowband filters for the miniCAM8M deepsky combo are customized by XiMei Filters. The LRGB filters have an optical density (OD) value of 3, while the narrowband filters have an OD value of 5.

The OD value, as a physical measure of the degree of light attenuation after passing through a filter, directly affects the filter’s ability to suppress unwanted light during imaging. A higher OD value indicates stronger suppression of stray light, effectively blocking most unnecessary light sources and thereby enhancing image contrast and detail clarity. 

The filters provided with the miniCAM8C deepsky combo are customized by Optolong Optics. These include a light pollution filter, a heavy light pollution filter, a four-channel enhancement filter, and a UV/IR cut filter.

 

miniCAM8M Planetary filters: 

7 filters: LRGB broadband filters, 20nm Methane filter, 40nm UV filter, 10nm Na filter (589nm)

 

 

miniCAM8M Sloan Photometric filters: UGRIZ

 

The peak quantum efficiency of the miniCAM8M reaches 91.2% in the OIII band, 80.9% in the Ha band, 78.7% in the SII band, and 40.1% in the methane band.

The peak quantum efficiency of the miniCAM8C: R channel: 82%; G channel: 87%; B channel: 75%.