Golf rangefinder teardown
Anatomy of a golf laser rangefinder
A golf rangefinder is the four subsystems the other ranging products carry - the emitter, the detector, the optics between them and the electronics that time the round trip - plus a fifth one they do not have: the tilt sensor and the display that turn a distance into a number the player can hit. Pick a part from the bill of materials and drop it on the unit; every parameter comes with the catalogue parts that carry it.
- 1Choisissez une pièce dans la nomenclature.
- 2Déposez-la sur le module, ou cliquez simplement la carte.
- 3Lisez son rôle, ses paramètres et les références qui les portent.
Nomenclature
Chaque pièce, un seul budget optique. Glissez une carte sur la photo, ou cliquez dessus : le panneau voisin se remplit avec les paramètres de cette pièce.
Glissez une pièce ici ou cliquez une carte dans la nomenclature
A handheld golf rangefinder, three-quarter view. The two apertures at the front left are the transmit and receive windows, the ocular is at the right, and the control ridge runs along the top.
Les positions des composants sont un schéma pédagogique, pas un plan de montage : le placement et la vue éclatée sont indicatifs. Les valeurs des paramètres sont celles de la spécification liée.
Chaque pièce, paramètre par paramètre
Les mêmes chiffres que la vue interactive, dans des tableaux que vous pouvez lire, rechercher et citer.
905 nm laser diode Transmitter
Emits the ranging pulse. On a golf unit peak power, pulse width and divergence are chosen for a few hundred metres and for thousands of measurements on one battery, so the compact end of the family is where the design starts - not the highest peak power on the list.
| Peak wavelength | 905 nm (895 - 915 nm) |
|---|---|
| Peak output power | 15 - 600 W |
| Pulse energy @ 100 ns | 1.5 - 30 uJ |
| Beam divergence, FWHM | 9 x 25 deg bare | 9 x 6 deg FAC |
| Pulse width | 1 - 100 ns (max 100 ns) |
| Duty cycle, max | 0.1 % |
| Repetition rate | up to 10 kHz |
| Package | TO56 | bare die | VCSEL array |
| Est. range, retro-reflective (40 W) | 755 m |
| Est. range, diffuse target (40 W) | 250 m |
Avalanche photodiode Receiver
Sets how weak a return the product can still trust. On a short-range unit the small-area packages are the right choice: less dark current and less capacitance than a large area, which is what keeps the timing edge sharp.
| Response spectrum | 400 - 1100 nm |
|---|---|
| Wavelength | 905 nm |
| Active area | 230 um TO-46 | 500 um LCC ceramic |
| Responsivity | 80 A/W @ M=100 |
| Response time | 0.5 ns |
| Dark current | 0.4 nA @ M=100 |
| Total capacitance | 1.0 pF @ M=100 |
| Optimum gain | 100 |
| Reverse breakdown voltage | 100 - 200 V |
| Optical filter | 905 nm spike filter |
| Package | TO-46 | LCC1 / LCC2 ceramic |
Emit / receive optics Optical path
Splits the light: the transmit aperture has to get the pulse out inside the receive aperture's field of view, and the receive aperture has to collect enough of the return without also collecting the transmitter's own glare.
| Optical channels | 2 ranging (transmit + receive) + observation path |
|---|---|
| Windows on the front face | 2 |
| Transmit beam, bare | 25 deg |
| Transmit beam, FAC | 6 deg |
| Receive aperture / focal length | Set by your optical design Fixé par votre conception |
| Transmission | To be confirmed against the drawing and a test band Fixé par votre conception |
| Receive filtering | 905 nm spike filter at the detector |
Drive and timing Electronics
Turns a stored capacitor into a nanosecond current pulse and turns the detector's edge back into a number. On a golf unit it also has to hold calibration across temperature, because the whole product is judged on repeatability.
| Peak pulse current | 70 A |
|---|---|
| Pulse width | 50 ns - 1 us adjustable |
| Repetition rate | 1 kHz - 30 kHz adjustable |
| Rise time | 7.5 ns typical |
| Fall time | 12 ns typical |
| Supply voltage | 12 V DC |
| Laser drive voltage | 1 - 50 V DC |
| Control interface | Internal trigger / external TTL |
| Factory default | 100 ns @ 3 kHz, internal trigger |
| Detector bias | 100 - 200 V reverse, temperature compensated Fixé par votre conception |
Tilt and display Interface
Adds the two things a plain rangefinder does not have - an angle, and a readable number. Which of the straight-line distance, the angle and a compensated distance the unit shows is a product decision, and a regulated one in some competitions.
| Tilt measurement range | To be confirmed: product specification Fixé par votre conception |
|---|---|
| Angle accuracy / resolution | To be confirmed: specification and calibration conditions Fixé par votre conception |
| Slope compensation | To be confirmed: whether this model supports it and how it is switched Fixé par votre conception |
| Display type / readout | To be confirmed: LCD, OLED or a projected reticle Fixé par votre conception |
| Buttons and modes | To be confirmed: product definition Fixé par votre conception |
| Indicator channel | Optional visible laser - see the parts below |
Chaque valeur de paramètre sur cette page est tirée de la fiche catalogue qui génère la page produit liée : les deux ne peuvent pas se contredire.
Pièces derrière ces paramètres
Chaque valeur ci-dessous provient de la même fiche catalogue que celle qui génère la page produit. Rien ici n'est retapé.
Handheld 905 nm transmit chain
A flag is a cooperative target a few hundred metres away, so the design starts at the bottom of the power range and spends the budget on repetition rate and battery life instead.
What the emitter is built from
Two ways to build the transmit source for a sealed handheld: take the bare stacked die and package it yourself, or take a VCSEL array that is already low-profile and rugged.
Receive chain
Short range means a small active area is not a compromise - it is the better choice: less dark current, less capacitance, a sharper timing edge.
Drive and timing
One board with the pulse generator and the driver on it, at a repetition rate a golf unit can actually use.
Indicator and aiming optics
For a unit that adds a visible aiming dot or an illuminated indicator next to the invisible ranging path.
This unit is the 905 nm / pulsed / short-range scenario
Run the selector with application = rangefinder, wavelength = 905 nm and output = pulsed, then keep the peak power low: a flag is a cooperative target a few hundred metres away, so the transmit chain below is taken from the compact end of the family. The catalogue carries the same four subsystems up to 1.6 km and 2.1 km if the product has to grow, and an eye-safe 1535 nm chain if it has to.
Tell us the range, the target and the size limit
A golf rangefinder is the tightest package in the ranging family: one battery, a few hundred metres and a number on a screen. Send us the range you need and the space you have, and we come back with the transmit chain, the receiver and the optics between them.
