Q&A
LCD Module
Adjusting the contrast of a character LCD module.
There are two means of adjusting the contrast: Please refer to the following drawing:
Internal: J2 short, add the appropriate resister to R7 for contrast control.
External: J1 short, R7=0, By adding a VR
Lens and Lens Modules
Why does the image look obscure?
a. Improper adjustment of back focal length
b. Incompatible lenses specification with sensor type c. Stained lenses.
Why are not the lenses fixed properly?
The screws or other interfaces between holders and barrels are not coincident. The solutions are that we provide the barrels and holders or design the barrel complying with the holder.
How to protect the lenses?
Lenses are fragile components. Please handle with care and protect free of dust. We suggest using of dust proof covers to prevent the damage or contamination. For the plastic material, the physical limitations are listed as follows
How to calculate angle of view(field of view) ?
See the figure shown below, where w is angel of view, f indicates focal length and y stands for image size. In trigonometric function, tan(w/2)=(y’/2)/f, therefore, w=2tan-1(y’/2f).
Aberration-see terminology for explanations.
Aberrations are summarized as below, and you can find the terminology for details.
Definition of pixel number?
CIF-100,000 pixels, 640*480 VGA300,000 pixels, 800*600 SVGA480,000, 1024*768 XGA 780,000pixels, 1280*1024 SXGA 1,300,000 pixels, 1600*1200 UXGA 1,920,000 pixels.
Definition of image sensor size?
The size of an image sensor is called its format. The name of a format does not correspond to any dimension. Historically, a one-half inch format is the size of the sensing area of a Vidicon tube, which is one-half inch
Design trade off between performance and cost.
As we described previously, aberrations always exist in optical system. We can decrease the aberration only by using more lenses in product design. Besides, wider field of view, higher resolution, larger illumination or magnification
