Hitachi DX07
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The Hitachi DX07 is a 2.9 inch (73 mm) liquid crystal display screen which went into mass production in December 2006:
- 62mm x 37mm
- 800x480 pixels
- 1.677 million colours
- 400:1 contrast ratio
- 250cd/m2
- IPS TFT (in-plane switching)
Each pixel is therefore 78µm x 77µm (1µm = 1/1000mm).
Note: It's also safe to assume that this is an 8-bit per channel display (a 6-bit per channel display can only dither 1.62 million colours)
Optical Properties of the DX07[]
The DX07 has a number of interesting properties related to its small size and high resolution. The following are true for someone with "normal" vision using this screen as a hand held device:
- Smallest pixel size to comfortably view a hand held device without loss of detail
- Smallest hand held screen without loss of detail for NTSC DVB content (720x480 pixels)
- Smallest hand held screen without loss of detail for NTSC DVD content (720x480 pixels)
Notes:
- "Normal" vision is when someone can distinguish detail at 1/60 of a degree (an arcminute)
- The closest a hand held screen can comfortably be viewed is 250mm (approx. 10 inches)
Smallest Visible Pixel Size for a Hand Held Device[]
The smallest visible pixel size (p) for a hand held device can be calculated assuming the screen is held at a comfortable distance (250mm) for someone with "normal" vision (able to see detail at a 1/60 degree angle):
It can therefore be concluded that the pixel size for the Hitachi DX07 screen is only 5% greater than the smallest possible for practical use.
Note: Smaller pixel sizes would dither in much the same way as printed dots (72.7µm is approximately 350dpi)
Other Hand Held Screen Sizes[]
If other hand held devices were manufactured for the latest high-definition video screen, then their smallest sizes without loss of detail (i.e. 72.7µm pixels) would be as follows:
Format | Pixels | Screen Size | Diagonal |
---|---|---|---|
DV NTSC | 480x720 | 35mm x 52mm | 63mm (2.5 inches) |
PAL | 576x720 | 42mm x 52mm | 67mm (2.6 inches) |
720p | 720x1280 | 52mm x 93mm | 107mm (4.2 inches) |
1080p | 1080x1920 | 79mm x 140mm | 160mm (6.3 inches) |
External links[]
- Hitachi products
- Liquid crystal displays
- Display devices