EVERYTHING YOU WANTED TO KNOW ABOUT HID:
High Intensity Discharge (HID) Bulbs:
How can an HID bulb work without a filament?
Its better to compare an automotive HID lamp with the well known fluoresent tube. Very simplistic, light is produced by sending current through metal vapor.
Why put the Metal rod down and the REFLECTIVE STRIP HORIZONTAL?
Yellow/orange sector. In a sector straight down from arc of the bulb, yellow/orange is higly visible. The direction will not change, even if bulb is rotated. In a OEM HID headlight, usage of this light sector is either totally blocked off, toned down and/or spread evenly into the rest of the beam so that headlamp output only have very minor or non yellow hotspots. How much this sector straight down from arc is utilized will directly affect the color that headlight emits.
Above: diagram of white versus yellow sectors.
Return wire shadow will always be present. However, if it faces down, it is within a toned down sector anyway (see regarding yellow sector above), so this should never be seen in the output from an OEM HID headlamp.
img]pic2[/img]
On all OEM HID headlamps that has been taken apart so far, return wire have been facing down. When it comes to aftermarked HID kits, return wire can face up, others down. Other directions than straigth up and straight down has not been spotted.
How even is the color and intensity across the arc (the light source)?
The ends of the arc has almost double the intensity and bluest color. Which means that optical engineers can make headlamp output bluer (or more yellow) than the bulb output color is, without using color filters (like they do in photograpy).
For HID retrofitting in halogen headlamps, this a feature that cannot be utilized. Its pretty obvious that a chromed reflector cannot be reshaped in any way. So a unlucky retrofitter CAN end up with color spectrum from brown to bright white - in different places of the beam.
What is color shift?
The labled light color on an HID bulb is an average that it will maintain over 2-3000 hours. After passing around 100-500 hours the phenonmen "color shift" will take place. Color will change slightly from a yellowish tone to a crisper bluer tone. The magnitude of color shift will vary depending on brand, model and rated color. It is a very gradual change and unless paid close attention to, a customer might not notice. OEM 4100K Bulbs manufactured by Philips has been reported to have a more noticeable color shift than OEM 4100K Osram. OEM 4100K Bulbs manufactured by Philips has a colorshift of approx 250K after 500 hours, which will bring it to up to 4350K.
Asian manufactured bulbs has been reported to have little or no color shift. Most of them come with output stealing blue filters, which may be part of the cause.
Why does a replacement bulb look yellow?
Its very rare that a high quality (Osram, Philips, GE) HID bulb break, but if it does happen it would be a normal thing purchase same brand and model. It is a normal thing that a replacement bulb of same brand and model will look more yellow. Up until now, dealers have told custmers that there is not much to do about it, unless both bulbs are
To be in front of the marked, Philips introduced the "Plus" range of HID bulbs, to have a product that will not look yellow in a situation like this.
How do I measure what color (in Kelvin) my bulbs are?
Many HID bulb resellers claim a certain color or Kelvin rating. Many times these bulbs is not the Kelvin rating they are supposed to have. The manufacturer know that the customer will never be able to measure this anyway. You can stare at the coating or salt micture for decades, but it will still end up being homebrew guestimates. It would require advanced measuring equipment worth several thousand dollars. Many customers buys HID kits second hand and needs spare bulbs. Unless part number listed on bulb, you are more or less traceing back a dead end. Resellers of HID kits comes and goes and manufacturers are changing specs faster than you change underwear.
Both Osram and Philips have P/N listed on bulbs, detailed specs are released on the web, and they stand behind their claim of lifetime.
Does HID bulbs need to be color matched?
Yes. Always get a matched pair. This means they must have the same:
manufacturer
part number
use time (if bought second hand)
Exceptions from this will show smaller or bigger differences in color, output and size of hotspot.
Why can HID lamps be dangerous?
A blast from a crushed 100 bar hot HID bulb will send glass pieces into your skin and eyes and potentially fill wounds with mercury, which is very poisiness. Room will be filled with toxic fumes. Very high startup voltages can give you electric shock if closer than 1.5 inches or 4 cm. A headlight assembly will protect you from all this included UV rays.
Why is HID lights totally blue for a few seconds after startup? THIS IS WHY I SUGGESTED SILICONE AROUND THE SEAM!
Due to the extreme complexity, this question has been condensed in to a MS Word document contributed by Ekooke, JustHitADeerWithHID, H1HID, and Mr.108
HID Phenomenon Document
What does D2R and D2S mean?
It may sound like some non meaningful letter combination, but there is actually a meaning to the madness:
D2S: Discharge second generation shielded
D2R: Discharge second generation reflection
What is the difference between D2R and D2S?
The main difference is the U-shaped masking on the D2R that blocks out unpredictable light in certain directions. Also, the base has different notches. Name of base is P32-d2 for D2S and P32-d3 for D2R. D2R was developed so that Mercedes could still use their reflector based headlights in the mid 1990s. They did not want use projectors like BMW. A glare box inside the headlight could have been used to accomplish a straight line, but a mask painted on the bulb was cheaper to make and had better precision. Other (near) luxury cars (Lexus, Infinity and Acura) followed Mercedes and equipped their cars with D2R bulbs in reflector based headlamps. Using a D2R in anything else than a OEM HID headlight designed for the D2R bulb makes no sense. BUSA HAS D2R HEADLIGHT ASSEMBLY SPECS FOR THE MOST PART.
It will only reduce output. Some HID kits comes with D2R bulbs. Some amateur kit designers will even claim that D2R genrally reduces glare in a retrofit. This is nonsense. The D2R bulb masking is around 3-4 a'clock and 8-9 o'clock when bulb is in right position. Those are not the (only) sectors that creates glare.
As an example, here is the data on Philips 2 versions:
D2S: 3200lm, 4250K, 91lm/W, 35W
D2R: 2800lm, 4150K, 80lm/W, 35W
PAGE 1 of 3
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High Intensity Discharge (HID) Bulbs:
How can an HID bulb work without a filament?
Its better to compare an automotive HID lamp with the well known fluoresent tube. Very simplistic, light is produced by sending current through metal vapor.
Why put the Metal rod down and the REFLECTIVE STRIP HORIZONTAL?
Yellow/orange sector. In a sector straight down from arc of the bulb, yellow/orange is higly visible. The direction will not change, even if bulb is rotated. In a OEM HID headlight, usage of this light sector is either totally blocked off, toned down and/or spread evenly into the rest of the beam so that headlamp output only have very minor or non yellow hotspots. How much this sector straight down from arc is utilized will directly affect the color that headlight emits.
Above: diagram of white versus yellow sectors.
Return wire shadow will always be present. However, if it faces down, it is within a toned down sector anyway (see regarding yellow sector above), so this should never be seen in the output from an OEM HID headlamp.
img]pic2[/img]
On all OEM HID headlamps that has been taken apart so far, return wire have been facing down. When it comes to aftermarked HID kits, return wire can face up, others down. Other directions than straigth up and straight down has not been spotted.
How even is the color and intensity across the arc (the light source)?
The ends of the arc has almost double the intensity and bluest color. Which means that optical engineers can make headlamp output bluer (or more yellow) than the bulb output color is, without using color filters (like they do in photograpy).
For HID retrofitting in halogen headlamps, this a feature that cannot be utilized. Its pretty obvious that a chromed reflector cannot be reshaped in any way. So a unlucky retrofitter CAN end up with color spectrum from brown to bright white - in different places of the beam.
What is color shift?
The labled light color on an HID bulb is an average that it will maintain over 2-3000 hours. After passing around 100-500 hours the phenonmen "color shift" will take place. Color will change slightly from a yellowish tone to a crisper bluer tone. The magnitude of color shift will vary depending on brand, model and rated color. It is a very gradual change and unless paid close attention to, a customer might not notice. OEM 4100K Bulbs manufactured by Philips has been reported to have a more noticeable color shift than OEM 4100K Osram. OEM 4100K Bulbs manufactured by Philips has a colorshift of approx 250K after 500 hours, which will bring it to up to 4350K.
Asian manufactured bulbs has been reported to have little or no color shift. Most of them come with output stealing blue filters, which may be part of the cause.
Why does a replacement bulb look yellow?
Its very rare that a high quality (Osram, Philips, GE) HID bulb break, but if it does happen it would be a normal thing purchase same brand and model. It is a normal thing that a replacement bulb of same brand and model will look more yellow. Up until now, dealers have told custmers that there is not much to do about it, unless both bulbs are
To be in front of the marked, Philips introduced the "Plus" range of HID bulbs, to have a product that will not look yellow in a situation like this.
How do I measure what color (in Kelvin) my bulbs are?
Many HID bulb resellers claim a certain color or Kelvin rating. Many times these bulbs is not the Kelvin rating they are supposed to have. The manufacturer know that the customer will never be able to measure this anyway. You can stare at the coating or salt micture for decades, but it will still end up being homebrew guestimates. It would require advanced measuring equipment worth several thousand dollars. Many customers buys HID kits second hand and needs spare bulbs. Unless part number listed on bulb, you are more or less traceing back a dead end. Resellers of HID kits comes and goes and manufacturers are changing specs faster than you change underwear.
Both Osram and Philips have P/N listed on bulbs, detailed specs are released on the web, and they stand behind their claim of lifetime.
Does HID bulbs need to be color matched?
Yes. Always get a matched pair. This means they must have the same:
manufacturer
part number
use time (if bought second hand)
Exceptions from this will show smaller or bigger differences in color, output and size of hotspot.
Why can HID lamps be dangerous?
A blast from a crushed 100 bar hot HID bulb will send glass pieces into your skin and eyes and potentially fill wounds with mercury, which is very poisiness. Room will be filled with toxic fumes. Very high startup voltages can give you electric shock if closer than 1.5 inches or 4 cm. A headlight assembly will protect you from all this included UV rays.
Why is HID lights totally blue for a few seconds after startup? THIS IS WHY I SUGGESTED SILICONE AROUND THE SEAM!
Due to the extreme complexity, this question has been condensed in to a MS Word document contributed by Ekooke, JustHitADeerWithHID, H1HID, and Mr.108
HID Phenomenon Document
What does D2R and D2S mean?
It may sound like some non meaningful letter combination, but there is actually a meaning to the madness:
D2S: Discharge second generation shielded
D2R: Discharge second generation reflection
What is the difference between D2R and D2S?
The main difference is the U-shaped masking on the D2R that blocks out unpredictable light in certain directions. Also, the base has different notches. Name of base is P32-d2 for D2S and P32-d3 for D2R. D2R was developed so that Mercedes could still use their reflector based headlights in the mid 1990s. They did not want use projectors like BMW. A glare box inside the headlight could have been used to accomplish a straight line, but a mask painted on the bulb was cheaper to make and had better precision. Other (near) luxury cars (Lexus, Infinity and Acura) followed Mercedes and equipped their cars with D2R bulbs in reflector based headlamps. Using a D2R in anything else than a OEM HID headlight designed for the D2R bulb makes no sense. BUSA HAS D2R HEADLIGHT ASSEMBLY SPECS FOR THE MOST PART.
It will only reduce output. Some HID kits comes with D2R bulbs. Some amateur kit designers will even claim that D2R genrally reduces glare in a retrofit. This is nonsense. The D2R bulb masking is around 3-4 a'clock and 8-9 o'clock when bulb is in right position. Those are not the (only) sectors that creates glare.
As an example, here is the data on Philips 2 versions:
D2S: 3200lm, 4250K, 91lm/W, 35W
D2R: 2800lm, 4150K, 80lm/W, 35W
PAGE 1 of 3
<!--EDIT|ICEMANN
Reason for Edit: None given...|1104813844 -->
