What is Contrast Ratio?

Contrast Ratio is the difference between the whitest white and the darkest black colors that the display can show. Generally speaking, the greater the contrast the better the screen and the subtlety of colors it can display.

Contrast ratio is often used when describing TVs. A high contrast ratio, such as 4000:1, signifies a better color representation (bright images will appear better against a darker background) than a lower contrast ratio, such as 2500:1. A 3000:1 contrast means 3000 times brighter than black. Typically, you want to purchase a projector or flat-panel TV with a high contrast ratio. Below are examples of different contrast ratio's.

Low Contrast When contrast is low, images appear washed out. Parts of the image may become difficult to see clearly. Projectors with contrast ratios of less than 500:1 typically provide low contrast. 

Simulated image of low contrast 

Medium Contrast When a projector provides good contrast, images are clear and attractive. Projectors with contrast ratios ranging from 500:1 to 1200:1 typically provide medium contrast. 
 
Simulated image of medium contrast 

High Contrast With high contrast, images are ultra crisp with vibrant colors. 
Projectors with contrast ratios exceeding 1200:1 typically provide high contrast. DLP TM (DDR) technology projectors currently offer these high contrast ratios. Additionally, some LCD projectors are able to offer high contrast ratios as well.
 
Simulated image of high contrast

 

Maintenance

How often should I clean the air filters?
Air filter cleaning varies with every location. Even clean residential or boardroom locations can collect enough dust in a very short time. Monitor the air filter in shorter periods (i.e. weekly) until a definite pattern is established. Make sure all the air intake vents are also cleaned by vacuuming the dust out.

How do I clean the air filters?

There are different types of air filters used in projectors. 

  1. Porous type (similar to a car filter) can be vacuumed to remove the debris, and should be replaced when necessary.
  2. Non-porous type – typically are made of plastic materials including foam materials are best cleaned by washing with mild detergent and dried before re-installed.

All intake and exhaust ports must also be vacuumed to remove debris accumulation. Never blow on air filters while in projector, or air intake ports. Debris will get blown to the LCD and polarizer surfaces.

 

 

 


Lamp Care

projectorlamps

 

Projector Lamps

How many hours will I get from my projector lamp?
Projector lamps have an expected operating life span. It can last up to 3000 hours, depending on model. However performance and life expectancy is not guaranteed due to the various conditions the projector has been operated, and maintenance performed.

Is the specified lamp hours standard in the projector industry?
There is no standardized lamp life measurement in the projector industry. There are two wide used types of lamp life determinations. Some manufacturers use brightness levels, i.e. the time it takes from 100% brightness (new) until it reach the 50% or 30% brightness level. Typically this method is called “maintenance”. And some use the “survival” method where a number of bulbs are operated simultaneously and time is measured until 15 – 40% of the lamp fail. Because of these variations between manufacturers, lamp hour’s statement should only be taken as a reference within the same manufacturer.

How can I prolong lamp life?

a. To maintain life of lamp, once you turn projector on, wait at least 5 minutes before turning it off.

b. Allow at least 3-5 minutes for the projector to cool down before re-starting. This is required to stabilize the lamp to its normal state. Igniting the lamp at high pressure will cause the bulb to explode.

c. Turn-off the projector ONLY by the top panel ON/OFF button or by remote control, never by interrupting the AC supply i.e. unplugging the AC cord. The projector requires AC power to operate the fan to cool down the optical components after the unit is turned-off.

d. Never re-start the projector immediately if the AC plugged has been disconnected accidentally. Wait at least 3-5 minutes before turning it on again.

e. Clean air filers regularly. Projector requires a constant flow of air to cool down the optical block and the most importantly the lamp. Note that bulbs operate at approximately 950º C. Any air restrictions such as dirt accumulation of the air filter will significantly further increase of the bulbs operating temperature, thus shortening the bulb life or cause premature failure.

f. Operating the projector in high ambient temperature (above 35ºC) also contributes to short life or premature failure.

g. Whenever possible use the eco-mode feature (lower brightness) when full brightness is not required.

Because of these user variables, projector lamps in the industry including SANYO have limited warranty of 1 year or 500 hours whichever comes first.

What happen when the yellow light illuminates? Will the projector shutdown?
Unlike many other companies in which the projector is forced to shut down when the lamp hours is reached, SANYO projectors will continue to function until the lamp is exhausted. However after this point, start-up may not be reliable. Suggest replacement immediately for critical applications (i.e. boardroom or classroom), or purchase a standby bulb for use on non-critical applications (i.e. home theater).

Toronto Office

91 Rylander Blvd,
Ste 7-148
Toronto, ON, M1B 5M5
Tel 416-460-2759
Fax 866-417-7542
Al McQueen al@epgi.ca

Hamilton Office

Tel 905-679-5885
Cell 905-577-3945
Bruce McQueen bruce@epgi.ca