I have a five year old son and no tv at home. Recently we were on holiday, just the two of us, and sometimes in the afternoons I was rather tired of being my son's pay pal, and allowed him to watch tv in the hotel room, so I could relax. After watching for half an hour or an hour of tv, when, with his consent, we turned the tv off and attempted to go out again or whatever, he was strangely aggressive and "high". To me that was a clear indication of what tv does to a child and why I have no tv at home.
Psychological research has shown a clear correlation between the amount of media consumption (tv, computer, video games) and the "excitation level" of the child, of his ability to concentrate, his aggression etc. Developmental psychologists recommend that children below the age of three should not watch television at all. They should learn about the world and experience it, before they experience virtuality. Let them lick their toys, eat sand, scrape their knees, learn to walk, feel the rain, AND EXPERIENCE OTHER HUMAN BEINGS, before they get nailed to the sofa and watch tv with vacant eyes.
Children at 14 months do not have an attention span longer that a few minutes. Children at five years can focus on one thing for as much as fifteen minutes. You see? Three years in the future, and fifteen minutes is normal development. You should adapt your expectations to your child's age. Go and get some good book on developmental psychology (e.g. Berk: Child Development, you can find it in any library I would guess, it is expensive) and learn what a child at 14 months can or cannot do. And get him away from tv. Don't give in to his tantrums, just do what YOU think is right for him. He does not know.
If you lack ideas of what to do WITH your child, stop thinking in that way. You are not brought into this world to be your child's entertainer. Take your child places where he can explore the world safely on his own. Go where there are other children. Children are not made to grow up alone at home. Take him out, create a group with other parents, etc. Think about what you would want at his age, and take him there. Make it fun for you and put him in that environment, and he will learn to make it fun for himself.
Avoid not only the "tv trap", as Dave Clarke put it, but also the boring plethora of toys trap. Children loose interest in their toys quicker, the more toys they have. One toy is a treasure, three toys are fun, but hundreds of toys devalue each other and make each other meaningless: it would not matter, if one toy were lost or broken, so none of the many toys matter. They matter as a whole, but not individually. Children with too many toys tend to start to break them on purpose. They are interested in having toys and getting new ones (shiny new bike), but they lose interest in each individual toy quickly, because a toy is not something to play with but something to get and to have and then to get more.
Clean up your child's toys. With his help, sort out anything that he does not play with (and take out some of the things he forgot about without showing them to him). Then stop getting new stuff for a few months.
Put him in a sling while you take walks. Go swimming with him. Read to him. Put him in a crib for a half the morning. Put him into life.