Enter: Cyclops

As most readers of The Avengers know, the group's resident synthezoid, the Vision, receives his solar power from a jewel in his forehead. But over time, this jewel has had its function tinkered with so that it now doubles as an emitter of a powerful solar energy force beam. In essence, it went from this:

to this:

Which seems almost redundant where the Vision is concerned, since he has other offensive capabilities which are more visually interesting than just picking off your foe(s) from a distance with another ray-beaming device. Even his "thermo-optic" heat rays which discharge from emitters in his eyes add more to the story, since they seem to be in the form of concentrated heat as opposed to his jewel's force ray. Look at the difference in effect between the two in an attack on Wonder Man:

The Vision could have just belted Wonder Man through that wall, for all the good his solar beam did--but a searing heat blast in the face is nothing to sneeze at.  I'll take a "GAA-AA!" over an "UFFF!" any day.

Although, honestly, artist Jack Kirby can make even the most ineffective attack look interesting:

But in the beginning, the Vision's jewel had a basic function: to absorb solar energy in order to supply him with power. I don't have the Vision's schematics on me, but from a design viewpoint it would seem to be optimally suited for that single purpose. I can't imagine the thing being large enough to have emitters that discharge anything more than a momentary flare-up--certainly nothing on the scale of a battering force beam. I'm reasonably sure his builder had the good sense not to have his primary power source double as something that would act to deplete the very energy he'd built up. And it seems too fragile to function as a weapon:

Though maybe Henry Pym and Tony Stark should compare notes, because they obviously have different approaches as far as how much energy the Vision can be given at a time:

Yet while it arguably wasn't meant to emit solar energy as a force beam, the jewel could still act as a conduit to allow the Vision's energy to be drained--that is, when the plot dictates:

If I'm remembering correctly, it wasn't until writer Steve Englehart began writing The Avengers that the Vision began using his solar jewel as a weapon (though it's entirely possible that artist Bob Brown got that ball rolling, and Englehart just picked it up and ran with it):

(Join the club if you, too, raised an eyebrow at the Swordsman's preposterous statement that the Vision's jewel beam is his "only trick" in a fight. Of course, I never expected the Vision to be beaten by a sword, no matter how "gimmicked" it is, so what do I know.)

But once the cat was out of this particular bag, it seemed that this dual feature of the Vision's absorption jewel was now the reality as far as future stories were concerned. And other artists, such as veteran Avengers penciller George Perez, were on board with it:

I'll have to take a look sometime at my solar-powered calculator, since this theoretically opens up a few doors as to its weaponry potential.

What.