Most of the entertainment gadgets or devices that we use has display or screen as a primary device. Some of the primary examples are televisions, computer monitors and smartphones. What makes a display to have more quality? Is the display size alone matters. NO! We have two main technical properties of display, Resolution Vs Pixel Density which decides its cost and quality. The term quality refers to the sharpness of the content on the display. We will see the basic overview of the technical terms and get into how to choose between displays with different resolution and pixel density. I will be using the terms “display” and “screen” which refers to any display(either a television display or computer monitor or even smartphone displays).
It is the smallest element that can be displayed on a screen. To be more simple, it is just a single dot on a display or a screen.
Usually displays are measured in size(in centimeters and inches). Here we only measure the diagonal size and not the horizontal or vertical size of the screen. There is also another important property of display which is the resolution. Resolution refers to size of the display in terms of pixels. E.g. Resolution of 800×600 pixels means that the there are 800 pixels horizontally and 600 pixels vertically. So therefore there are a total of 480000 pixel in the display.
Resolution is just the number of pixels on the display and this property alone does not measure the quality of display.
Many of us are not aware of the importance of Pixel Density in displays. It is the thing which describes the sharpness and clarity. Pixel Density is usually measured in PPI (Pixels Per Inch) which refers to number of pixels present per inch on the display. Higher the pixel density higher is the sharpness of the content. Pixel Density is calculated based on the resolution and size of the display.
Pixel Density= Root((Horizontal Number of Pixel^2) + (Vertical Number of Pixel^2))/Screen Size
Consider the above image. The alphabet “A” on the left is displayed on screen(32 inch display) with lower resolution. The alphabet “A” on the right is displayed on the screen(32 inch) with higher resolution which delivers better sharpness.
Which is important?”
Consider we have a Full-HD TV with size 32 inches and resolution of 1080p (1920×1080 pixels). For the given specification, the pixel density comes to around 68.84 ppi.
E.g. Pixel Density = Root((1920^2)+(1080^2))/32=68.84 ppi
Consider we have a Nexus 5 smartphone which has a 4.95 inch Full-HD display. For this smartphone, the pixel density comes to 445 ppi.
Nexus 5 has better pixel density(more than 6 times of 32 inch TV). Does this mean that Nexus has better quality display. Yes, the smartphone do have better Pixel Density.But we cannot actually compare display of the smartphones with big 32 inch TV because the applications and usage are completely different.
Televisions are gadgets which we see from a certain display, say 7 or 8 feet. When we are seeing a 32inch Full-HD display in a distance of 7 to 8 feet, we will feel great sharpness and clarity. If we go near the display, may be one feet near the display, we may find degradation in the quality of the image. TV displays are designed in such a way to see it with certain distance. i.e. we can see the content on the display pixellated. The human eye cannot see the individual pixels if the human is viewing the display from 3 to 4 feet distance.
Consider in the case of smartphones, they are designed to use in just 1 to 2 feet distance. So we can feel greater sharpness only if the display has higher pixel density. So it is mandatory to manufacture smartphones with higher pixel density compared to televisions.