There are two main patterns we can use to construct controller functions in Angular. The classic way is to use $scope to link controllers to views as such:

// View: <div ng-controller='LabController'></div>
app.controller('LabController', function ($scope) {
  $scope.labEquipment = {
    labEquipmentProperty: 'Some value'
  };
});

Since Angular version 1.2.0, we could use the this and Controller as syntax:

// View: <div ng-controller='LabController as lab'></div>
app.controller('LabController', function () {
  this.labEquipment = {
    labEquipmentProperty: 'Some value'
  };
});

These two paradigms are generally interchangeable. However, binding properties to the view using $scope is an expensive operation, so the use of this can be advantageous for keeping $scope uncluttered. But when using this, make sure to check that it is bound the the proper scope!

Whichever paradigm you choose, remember that the use of one pattern over another should remain consistent within an application, and $scope does need to be injected into the controller to use $scope functions such as $watch and $digest.

Check out the resources below for a more in-depth exploration of $scope and this syntax.

Resources

1. Digging into Angular's "Controller as" syntax by Todd Motto
2. Rethinking AngularJS Controllers by Todd Motto
3. Do You Like Your Angular Controllers with or without Sugar? by John Papa