A computer monitor is a specialized display device that has been designed and manufactured specifically for displaying sharp images (including especially text) at the sort of distance a PC user is likely to sit in front of the display. An LCD HDTV can be used as a monitor however, there are a number of factors which make it a less optimal solution than a monitor.

Pixel Pitch

A small pixel pitch (space between pixels) is how PC monitors are able to display a high resolution image which can be viewed comfortably from a short distance – less than a desk width away. Pixel pitches for monitors are smaller than for HDTVs and can go down to 0.18 mm or even lower. For HDTVs you might find that a 32 inch model has a pixel pitch around 0.36 mm and a 55 inch might be as high as 0.5 mm. The larger the pixel pitch, the further away a comfortable viewing distance is (no graininess due to pixel structure being distinguishable. For a desktop monitor it’s not a good idea to go over a pixel pitch of 0.28 mm.

If a larger HDTV is used as a monitor for a PC functioning primarily as a media server, a larger viewing distance may not be an issue.

Resolution

The primary reason that HDTVs can now be considered as PC monitors was the advent of progressive displays (eg. 720p, 1080p). Progressive displays show all lines of an image in a single frame rather than splitting alternate lines between successive frames which is interlacing (eg. 720i). As text displays poorly on interlaced displays, progressive is the only viable format.

A display will always render the best image when the source video resolution matches the native resolution of the display. If they don’t match then the video processor must scale the video frames to match the native resolution and although scaling is done very well by most HDTVs, there will always be some element of noise introduced.

Life wasn’t meant to be simple and unfortunately the lack of common native resolutions between computer monitors and HDTVs is another shining example. Complicating the situation is the mismatch between the widescreen HDTV aspect ratio (ratio of number of horizontal pixels to vertical pixels) of 16:9 and the most common 16:10 aspect ratio for PC monitors. Despite these problems, similar PC resolutions can be displayed natively (no scaling) on a HDTV with the use of black borders (letterboxing).

HDTV manufacturers publish the PC resolutions they support in their user manuals (generally available online and referenced in our reviews if so) and you will need to pick one closest to but smaller than the native resolution of your HDTV. There are a couple of technologies which can make finding a good match easier. First, some of the latest PC video cards make it possible to set your desktop to just about any resolution you desire. Second, there are software packages like Powerstrip for Windows or DisplayConfigX for Macs which provide the flexibility to set custom resolutions.

Overscan

Unfortunately resolution is not the only issue to address. Unlike PC monitors, all TV’s are subject to some overscan, with at least a few percent being shaved off frame edges. Overscan is not noticeable on a HDTV as television producers avoid placing any significant content at the frame margins.

It is a different story with a PC however, where functionally significant elements are commonly placed on the extremities and losing them to overscan needs to be avoided. Fortunately, overscan can be removed by accessing a HDTV’s settings menu and calling up a 1:1 pixel mapping mode. As an example, Samsung have a Screen Fit setting which “displays the full image without any cut-off”.

PC – HDTV Connections

A digital connection is preferable with the best PC and HDTV option being a single HDMI cable which will carry both video and audio signals. The second option is a DVI to HDMI one using a HDMI to DVI Adapter Cable for video and the digital audio out for audio. Manufacturers provide PC – HDTV connection options in their user manuals. User manuals are available online and are linked to in our reviews.

Backlight Uniformity

Uniform backlighting is essential when sitting close to a monitor or HDTV/monitor. It is easier for a manufacturer to achieve with a smaller display size.

Pixel Response Time

A smaller pixel response time is better delivering sharper, crisper images with no fast motion ghosting. Gamers would view a quick response time as essential. Pixel response time is measured in milliseconds (ms) and is the time it takes for a pixel to change from black to white and back to black again.

Fortunately, finding an LCD with a suitably fast response time of 8 ms is a fairly easy ask. Some higher end LCD HDTVs are available with response times of 2 ms.

HDTV as a PC Monitor – Conclusion

As mentioned initially, HDTVs, unlike PC monitors, are not specifically designed for a personal computer display usage scenario. However, it is possible to use a HDTV successfully if the issues we have noted are considered in selecting a suitable HDTV. Additionally, the HDTV’s user manual needs to followed closely with regard to details such as; acceptable input resolutions, connections and PC settings.

Resources

Common LCD monitor dot pitches