Stage lighting fixture

1. A stage lighting fixture comprising:

a casing extending along a longitudinal axis the casing a closed end and an open end opposite to the closed end along the longitudinal axis;

a light source arranged inside the casing for emitting a light beam along an optical axis;

a reflector coupled to the light source;

at least one dichroic filter for selectively intercepting the light beam; and

at least one heat-shield assembly located between the light source and the dichroic filter; the heat-shield assembly comprising a heat-shield filter having a first portion with first beam filtering properties, and a second portion with second beam filtering properties differing from the first beam filtering properties; and the first portion and the second portion being substantially planarly contiguous, wherein the heat-shield assembly further comprises a plate for supporting the heat-shield filter.

2. A lighting fixture as claimed in claim 1 , wherein the first portion is located at the centre of the heat-shield filter, and the second portion surrounds the first portion.

3. A lighting fixture as claimed in claim 1 , wherein the first portion is circular and located at the centre of the heat-shield filter; and the second portion is annular and surrounds the first portion.

4. A lighting fixture as claimed in claim 3 , wherein the light source comprises a bulb which has a centre portion housing two electrodes, and two substantially tubular lateral portions; the first portion being sized on the basis of the size of the lateral portion next to the heat-shield assembly.

5. A. lighting fixture as claimed in claim 1 , wherein the heat-shield filter is defined by a number of coupled members.

6. A lighting fixture as claimed in claim 5 , wherein the heat-shield filter is defined by a first member and a second member, each of which comprises half of the first portion and half of the second portion.

7. A lighting fixture as claimed in claim 5 , wherein the heat-shield filter is defined by a first member and second member coupled to define the second portion; a third member defining the first portion; and a fourth member, fifth member, and sixth member for supporting the third member.

8. A lighting fixture as claimed in claim 1 , wherein the second portion is designed to filter hot light in the invisible range, and the first portion is designed to filter hot light in the visible range.

9. A lighting fixture as claimed in claim 1 , wherein the first portion has a transmittance of roughly 0.1 to 0.5% for wavelengths of roughly 400 to 650 nm.

10. A lighting fixture as claimed in claim 1 , wherein the first portion has a transmittance of over 20% for wavelengths of roughly 650 to 1000 nm.

11. A lighting fixture as claimed in claim 1 , wherein the second portion has a transmittance of over 90% for wavelengths of roughly 425 to 680 nm.

12. A lighting fixture as claimed in claim 1 , wherein the second portion has a transmittance of least than 3% for wavelengths of roughly 800 to 1150 nm.

13. A stage lighting fixture comprising

a light source for emitting a light beam along an optical axis;

a reflector coupled to the light source;

at least one dichroic filter for selectively intercepting the light beam;

at least one heat-shield assembly located between the light source and the dichroic filter;

the heat-shield assembly comprising a heat-shield filter having a first portion with first beam filtering properties, with a second portion with second beam filtering properties differing from the first beam filtering properties; and the first portion and the second portion being substantially planarly contiguous; and

a frame having a central hole to let the light beam through, and designed to support the heat-shield filter over the central hole.

14. A stage lighting fixture comprising

a casing extending, along a longitudinal axis, the casing having a closed end and an open end opposite to the closed end along the longitudinal axis;

a light source arranged inside the casing for emitting a light beam along an optical axis;

a reflector coupled to the light source;

at least one dichroic filter for selectively intercepting the light beam; and

least one heat-shield assembly located between the light source and the dichroic filter, the heat-shield assembly comprising a heat-shield filter having a first portion with first beam filtering properties, and a second portion with second beam filtering properties differing from the first beam filtering properties, wherein the first portion and the second portion are substantially planarly contiguous and the second portion is designed to filter hot light in an invisible range, and the first portion is designed to filter hot light in a visible range; wherein the heat-shield assembly comprises a frame for supporting the heat-shield filter.

15. A stage lighting fixture comprising:

a casing extending along a longitudinal axis, the casing having a closed end and an open end opposite to the closed end along axis;

a light source for emitting as light beam along an optical axis: the light source being housed inside the casing;

a reflector coupled to the light source;

at least one dichroic filter for selectively intercepting the light beam;

at least one heat-shield assembly located between the light source and the dichroic filter; the heat-shield assembly comprising a heat-shield filter having a first portion with first beam filtering properties, and a second portion with second beam filtering properties differing from the first beam filtering properties; and the first portion and the second portion being substantially planarly contiguous; and

a plate which is fitted to the casing, has a central hole to let the light beam through, and is designed to support the heat-shield filter over the central hole.