Custom 24V LED Ladder Backlight Curtain for Light Boxes
Wallis LED ladder backlight is a modular direct-lit illumination system designed for SEG fabric light boxes, advertising displays, retail signage, menu boards, exhibition graphics, translucent wall panels and other large-format backlit structures.
Multiple rigid LED bars are connected by cables or compatible connectors to form a ladder-shaped or curtain-style lighting array. This pre-arranged structure reduces on-site wiring work and helps maintain consistent spacing across the complete light box.
The standard A-M21DD-980 LED bar is 980mm long and uses SMD2835 LEDs with wide-angle PMMA optical lenses. The currently listed configuration provides 5W power, 500lm nominal luminous flux, 24V input, 6500K cool-white light and a 170° beam angle.
Wallis supports custom LED-bar length, ladder width, bar spacing, color temperature, cable direction, connector type, dimming, PCB branding and complete lighting layouts according to the finished light-box dimensions and brightness requirements.
A-M21DD-980 LED Ladder Backlight Specifications
| Product Type | LED Ladder Backlight / LED Curtain / Direct-Lit Light Box Backlight |
| Model | A-M21DD-980 |
| Standard Bar Length | 980mm |
| Rated Power | 5W per listed 980mm bar |
| Nominal Input Voltage | DC24V |
| Listed Voltage Range | The feature description states DC24–30V; confirm the tested operating range before using a voltage above 24V |
| Nominal Luminous Flux | 500lm |
| Derived Nominal Efficacy | Approximately 100lm/W based on 500lm ÷ 5W |
| Standard Color Temperature | 6500K cool white |
| Custom Color Temperatures | Current page lists 3000K / 4000K / 4500K / 6000K; confirm LED bin and CCT tolerance |
| LED Type | SMD2835 |
| Optical Lens | Wide-angle PMMA lens |
| Beam Angle | 170° |
| Circuit Design | Constant-current design; current page states conversion efficiency above 95%, subject to test-method confirmation |
| Connection Options | Soldered Cable / Plastic Connector / Customized Wiring Harness |
| Cutting | Every 3 LEDs at marked positions; minimum listed cut section approximately 170mm |
| Reference Minimum Light Box Depth | Approximately 40mm for the currently described arrangement |
| Reference LED-Bar Spacing | Approximately 80mm for the currently described 40mm-depth configuration |
| Dimming | Available with a compatible driver or controller; control method must be confirmed |
| Recommended Environment | Indoor light boxes unless a verified waterproof configuration is ordered |
| Listed Warranty | 2 years; request the complete warranty terms for the ordered model |
| Listed Compliance | Current page states CE, RoHS and UL; request valid reports or certificates applicable to A-M21DD-980 |
Important: Lumens, power, color temperature and beam angle describe the LED bar, not the finished light-box surface. Final lux, cd/m² and uniformity depend on the ladder layout, box depth, graphic material, reflector, interior color and measurement method.
![LED ladder backlight bars connected as a curtain for a light box]( "LED Ladder Backlight Curtain")
Connected as an LED Backlight Curtain
![Connectors cables and related accessories for LED ladder backlighting]( "LED Ladder Backlight Accessories")
Cables, Connectors and Related Accessories
What Is an LED Ladder Backlight?
An LED ladder backlight is a pre-connected array of linear LED bars positioned behind a translucent graphic or diffuser. Vertical cables or wiring harnesses connect the horizontal bars, creating a structure that visually resembles a ladder or lighting curtain.
Unlike edge-lit LGP panels, a ladder backlight is a direct-lit system. The LEDs face toward the graphic, and each PMMA lens spreads light over a wide area before it reaches the fabric, acrylic diffuser or backlit film.
Pre-Spaced Modular Structure
The bars can be manufactured with predetermined spacing and wiring, reducing the need to position and connect individual LED modules inside the light box.
Wide-Angle Optical Lenses
Each LED is paired with a wide-angle lens that distributes light laterally. The listed 170° beam helps adjacent light patterns overlap, reducing obvious bright points and dark gaps.
Direct Backlighting
The system illuminates a graphic from behind without requiring a laser-dotted acrylic light guide panel. It is particularly suitable for medium-depth and large-format light boxes.
LED Ladder Backlight vs Edge-Lit LGP Panel
| Comparison | LED Ladder Backlight | Edge-Lit LGP Panel |
| Lighting Method | Direct LEDs installed behind the graphic | LEDs inject light through acrylic panel edges |
| Main Optical Component | Wide-angle lens | Laser-dotted PMMA light guide panel |
| Typical Box Depth | Approximately 40mm or more for the current Wallis arrangement | Can support thinner profiles depending on the optical design |
| Large-Format Scalability | Easily expanded by adding bars and ladder sections | Limited by LGP size, light-travel distance and panel handling |
| Custom Shapes | Flexible for rectangular and selected irregular housings | LGP can be CNC processed but requires custom optical patterning |
| Installation | Ladder can be unrolled, fixed and connected inside the box | Requires precise alignment of the LEDs with the LGP edges |
| Typical Applications | SEG fabric boxes, exhibition graphics and large advertising displays | Slim poster frames, menu boards and compact illuminated panels |
Key Advantages of the Wallis LED Ladder System
Wide 170° Light Distribution
Wide-angle PMMA lenses spread light across a larger surface than an uncovered LED. Overlapping beam patterns can improve uniformity and permit wider spacing than narrow-beam modules, subject to the light-box depth and graphic material.
Nominal 100lm/W Performance
Based on the currently listed 500lm and 5W values, the standard model has a nominal calculated efficacy of approximately 100lm/W. Contractual performance should be based on an approved test report and defined measurement conditions.
Faster Large-Format Installation
Pre-connected ladder sections help installers maintain consistent spacing and reduce repetitive cable assembly inside large advertising boxes.
Flexible Cutting and Connection
The current product can be cut at designated positions every three LEDs, with a listed minimum section of approximately 170mm. Sections can be connected by cables or approved connectors.
Constant-Current Lighting Design
Constant-current control helps stabilize LED operating current and reduce brightness differences caused by normal voltage variation. The permitted series length and driver capacity must still be calculated for each installation.
Custom Ladder Dimensions
The number of bars, bar length, cable length, horizontal spacing and overall curtain width can be adjusted to match the light-box dimensions.
Dimming Support
Dimming can be provided when the LEDs, driver and controller are electrically compatible. Buyers should specify the required control method before production.
How Light Box Depth and Bar Spacing Affect Uniformity
The distance between the LED lenses and the illuminated graphic determines how much space is available for individual beam patterns to overlap. If the box is too shallow or the bars are spaced too widely, bright lines and dark bands may remain visible.
Current 40mm / 80mm Reference Configuration
The current Wallis page describes approximately 40mm as the thinnest suitable profile and approximately 80mm as the LED-bar spacing. Treat these figures as a starting reference for the shown lens and graphic system, not as universal installation limits.
Shallower Light Boxes
A shallow enclosure generally requires closer bar spacing, stronger diffusion or a different optical lens to prevent individual LED lines from appearing through the graphic.
Deeper Light Boxes
Increasing the distance between LEDs and the graphic gives light more space to spread. This may permit wider spacing, but the final result must still meet the required brightness and uniformity.
Graphic Transmission and Diffusion
Highly translucent graphics transmit more light but may reveal LED patterns. More diffusing graphics hide hotspots more effectively but can reduce total surface brightness.
Reflective Interior Surface
A clean white or purpose-designed reflective back surface redirects stray light toward the graphic and can improve efficiency. Dark or absorbent interiors reduce usable light.
Recommended Prototype Testing
For new light-box sizes or appearance-sensitive projects, the ladder layout should be tested with the actual frame depth, graphic material, reflective backing, power supply and ambient lighting conditions.
| Test Parameter | Recommended Buyer Requirement |
| Surface Luminance | Define the required average value in cd/m² and the measurement grid. |
| Minimum Brightness | Define the minimum acceptable reading at corners or between bars. |
| Lighting Uniformity | Specify whether uniformity is calculated as minimum/average or minimum/maximum. |
| Visible Hotspots | Evaluate the box from the normal viewing distance using the actual printed graphic. |
| Power Consumption | Measure the complete ladder and power supply rather than multiplying nominal bar wattage only. |
| Color Temperature | Define target CCT and allowable variation between bars and production batches. |
| Color Rendering Index | Specify CRI where accurate display of brand colors, food, cosmetics or artwork matters. |
| Thermal Test | Measure LED, PCB, cable and driver temperatures after the intended operating period. |
| Aging Test | Verify stable illumination, connectors, wiring and driver operation before shipment. |
Cutting and Connecting the LED Bars
Cut Only at Marked Positions
The current design can be cut every three LEDs, with a minimum listed section of approximately 170mm. Cutting outside the designated location may interrupt the circuit or damage the constant-current arrangement.
Cable Connection
Soldered cables provide a compact customized wiring solution. Cable gauge, insulation, polarity, length and current capacity must be suitable for the complete lighting array.
Plastic Connector Assembly
Compatible connectors can simplify replacement and installation by reducing on-site soldering. Connector current rating and locking reliability should be confirmed for the final quantity of bars.
Maintain Correct Polarity
Mark and verify positive and negative wiring before energizing the system. Reverse polarity or incorrect series/parallel wiring can prevent operation or damage components.
![LED ladder backlight installed behind an illuminated display surface]( "LED Ladder Backlight Application")
LED Ladder Backlighting Application
![Dimming controller for LED ladder backlight lighting system]( "LED Ladder Backlight Dimming")
Compatible Dimming Control
Power Supply and Wiring Design
Use a Regulated 24V Power Supply
The standard model table specifies 24V. Use a regulated power supply whose output matches the confirmed LED-bar voltage and whose wattage exceeds the calculated connected load by an appropriate design margin.
Calculate the Total Connected Power
Multiply the confirmed wattage per bar by the number of bars and sections connected to each power circuit. Include losses, dimming equipment and the power-supply reserve in the final calculation.
Control Voltage Drop
Long cables and high current can cause voltage drop and visible brightness differences. Large light boxes may require multiple feed points or divided power circuits.
Provide Access to the Driver
Install the power supply in a ventilated and serviceable location. Avoid sealing it permanently behind the display without maintenance access.
Confirm Electrical Certification
The LED bars, connectors and external driver may have different compliance documents. Buyers should specify the destination market and required certifications for the complete supplied system.
Color Temperature and Dimming Options
3000K Warm White
Warm-white lighting creates a softer visual effect for hospitality, interior decoration, premium retail and selected menu displays.
4000K to 4500K Neutral White
Neutral-white options provide a balanced appearance for offices, exhibitions, general retail and informational signs.
6000K to 6500K Cool White
The standard A-M21DD-980 table lists 6500K, while the customization text lists 6000K. Confirm the exact target CCT, LED bin and allowable tolerance before production.
Dimmable Lighting
Dimming is possible with a compatible constant-voltage or constant-current control system selected for the final LED arrangement. Specify PWM, 0–10V, DALI or another control method where required.
Applications of LED Ladder Backlighting
SEG Fabric Light Boxes
Ladder arrays can illuminate silicone-edge fabric graphics in retail stores, exhibitions, showrooms and commercial interiors. Layout testing should use the actual SEG textile and printed ink density.
Advertising and Poster Light Boxes
Direct LED backlighting provides strong illumination for translucent advertising films, cinema graphics, promotional posters and large indoor information displays.
Retail Display Walls
Large ladder sections can be installed behind illuminated brand walls, product graphics and seasonal campaign displays.
Menu Boards
Cool-white or neutral-white configurations can illuminate menu graphics in restaurants, food courts and service counters.
Exhibition and Trade Show Displays
Lightweight pre-connected LED curtains can reduce installation time for temporary exhibition graphics and modular display frames.
Translucent Decorative Walls
Ladder lighting can be installed behind stretch ceilings, translucent decorative materials and selected architectural surfaces where a direct-lit structure is appropriate.
Large Display Backlighting
The system can provide general backlighting for display-style assemblies. Precision LCD backlight units require additional optical films, thermal design and display-specific engineering and should not be treated as a direct plug-in replacement.
Indoor and Outdoor Installation
The standard model is described as an indoor high-brightness LED bar. The current product page does not provide a verified IP rating for A-M21DD-980.
Outdoor light boxes require a purpose-designed waterproof LED version, sealed connectors, drainage, protected cable entries, a suitable outdoor driver and a verified IP rating for the complete installation.
Do not assume that CE, RoHS or UL-related documents establish waterproof performance. IP protection and electrical compliance are separate requirements.
Quality Control and Compliance Verification
PCB length, width and cutting-position inspection
LED quantity and SMD2835 placement inspection
PMMA lens alignment and adhesion inspection
Input-voltage and operating-current test
Power-consumption measurement
Luminous-flux or efficacy verification where required
Color-temperature and color-consistency inspection
Cable polarity and connector test
Open-circuit and short-circuit inspection
Dimming compatibility test where applicable
Lighting-uniformity prototype evaluation
Thermal and aging test
Packaging and transport-protection inspection
Verification of applicable CE, RoHS, UL or other destination-market documents
Certification Scope
The current page states CE, RoHS and UL certification. Before using these claims in tender documents, packaging or marketplace listings, request certificate numbers and verify that the model, PCB, LED, voltage and manufacturing entity match the ordered product.
Warranty Scope
The current page lists a two-year warranty. Buyers should confirm whether the warranty covers LED failure, lumen depreciation, color shift, lenses, connectors, cables and external drivers.
Custom LED Ladder Backlight Services
Wallis supports project-based LED ladder manufacturing for light-box producers, signage companies, retail-fixture factories, exhibition contractors and lighting distributors.
Custom LED-bar length
Custom ladder width and overall dimensions
Custom vertical spacing between LED bars
Custom cable length and wiring direction
Cable or connector assembly
3000K, 4000K, 4500K and cool-white configurations
Custom brightness or power requirements
Dimming-compatible configurations
PCB logo and private-label printing
Custom driver and accessory matching
Lighting-layout recommendation
Prototype and sample testing
Custom carton, label and export packaging
OEM / ODM volume production
Information Needed for an Accurate Quote
Finished light-box width and height
Internal light-box depth
Single-sided or double-sided graphic
Graphic or diffuser material
Required average luminance or illuminance
Required lighting uniformity
Required LED-bar length
Preferred bar spacing
Color-temperature requirement
Required CRI
Total order quantity
Cable or connector preference
Cable exit and power-supply location
Dimming or control requirements
Indoor or outdoor environment
Required IP rating
Required compliance documents
PCB logo or private-label requirement
Packaging requirements
Light-box drawing, photograph or installation diagram
Frequently Asked Questions About LED Ladder Backlights
What is an LED ladder backlight?
It is a pre-connected array of linear LED bars used for direct backlighting. The bars are arranged like ladder rungs and connected by cables or wiring harnesses to illuminate a translucent graphic from behind.
What is the standard model?
The standard model shown on this page is A-M21DD-980, with a listed length of 980mm, power of 5W, nominal luminous flux of 500lm and 170° beam angle.
Does the LED bar use 24V or 24–30V?
The standard model table specifies 24V, while the feature description mentions a DC24–30V range. Use 24V as the nominal value unless Wallis supplies a test report confirming the wider operating range.
What is the nominal luminous efficacy?
Based on the currently listed 500lm and 5W values, the calculated nominal efficacy is approximately 100lm/W. Request a test report if efficacy is a contractual purchasing requirement.
Can the LED ladder bar be cut?
Yes. The current design can be cut every three LEDs at marked positions. The listed minimum cutting section is approximately 170mm.
Can the bars be reconnected after cutting?
Sections can be connected using correctly rated cables or compatible connectors. Polarity, current capacity and circuit configuration must be maintained.
What is the thinnest suitable light box?
The current page recommends approximately 40mm as the thinnest suitable profile for the shown configuration. Uniformity generally improves with more optical mixing distance, although every design should be tested.
What spacing should be used between the LED bars?
The current page uses approximately 80mm as a reference. The correct spacing depends on box depth, lens, graphic transmission, reflector and brightness target.
Will 80mm spacing work in every light box?
No. A shallower box, more transparent graphic or higher uniformity requirement may need closer spacing. A prototype should be tested using the final enclosure and graphic material.
How many LED bars are needed for one light box?
The quantity depends on the internal width or height, selected spacing, light-box depth and required brightness. Wallis can prepare a layout after receiving the complete dimensions.
What color temperature is standard?
The A-M21DD-980 table lists 6500K. The current page also lists 3000K, 4000K, 4500K and 6000K as customization options.
Can the LED ladder backlight be dimmed?
Yes, when the LEDs, power supply and dimming controller are compatible. Specify the required control method before production.
What is the CRI?
The current page does not publish a CRI value. Buyers should specify the required CRI for food, cosmetic, fashion, artwork or brand-color applications.
Can the system be used in an SEG fabric light box?
Yes. SEG fabric light boxes are a primary application. The bar layout should be tested with the actual fabric, print density and frame depth.
Can it illuminate a double-sided light box?
A double-sided system can be designed, but it may require LEDs facing both graphics or a special bidirectional optical arrangement. Provide the complete cross-section for evaluation.
Is the standard product waterproof?
The current A-M21DD-980 page does not publish a verified IP rating. Treat it as an indoor product unless a waterproof version and supporting test documentation are confirmed.
Does the product have CE, RoHS and UL certification?
The current product text states CE, RoHS and UL. Request current certificates or reports and confirm that they specifically cover the ordered model, voltage and manufacturing entity.
What warranty is available?
The current page lists a two-year warranty. Confirm the operating conditions, excluded components and replacement procedure before placing the order.
Can Wallis print our logo on the PCB?
Yes. Custom PCB branding can be discussed after the artwork, printing position, color and order quantity are confirmed.
What is the MOQ?
The current page states that standard products without logo printing usually start from 10 pieces, while logo-printed orders usually start from 100 pieces. Confirm the current MOQ for the required configuration.
Can samples be supplied before bulk production?
Yes. Sample and prototype testing are recommended before bulk production, especially for custom spacing, strict brightness targets or unusual light-box depths.
Which shipping ports are available?
The current page identifies Shanghai as the nearest sea port and states that Ningbo or Shenzhen may also be used depending on the shipping arrangement.
What information should I provide for a quotation?
Provide the light-box dimensions, internal depth, graphic material, brightness target, color temperature, bar spacing, quantity, connection method, driver location, dimming requirement, environment and required certifications.
Request Custom LED Ladder Backlight Samples and Pricing
Looking for a custom LED ladder backlight manufacturer for SEG fabric light boxes, advertising displays, retail walls, exhibitions or translucent signage? Wallis provides SMD2835 LED bars, wide-angle PMMA lenses, custom ladder layouts, connectors, dimming options and PCB branding.
Send your light-box width, height, depth, graphic material, required brightness and order quantity to receive a suitable LED layout, prototype recommendation and factory quotation.
