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Bowmar R7H-122-9 Nine-Digit Calculator LED Display

• Features

These Nine-Digit Calculator Numeric Seven-Segment LED Displays known as Bowmar Optostic are intended for use under pulsed conditions by enabling the common cathode of each digit sequentially and enabling the desired Segment and Decimal Point anodes in phase with the character enabling pulse. The pulse rate is kept high enough so that light from each character appears to the eye to be constant.

The R7H-122-9 Nine-Digit display assembly uses Chip-on-Board (COB) technology with each character formed by bonding seven individual Segment LED chips and one Decimal Point LED chip directly to a printed circuit board (PCB) and protecting them with a one-piece flat protection lens.

The leftmost character misses one segment and its decimal point and is typically used to display the minus sign of negative numbers, any number entry or calculating overflow conditions, and with some calculator chips as Memory indicator.

• 0.12”/3.0 mm Characters
• Seven-Segment Digits with Right-Hand Decimals
• Continuous Uniform Segments
• Wide Viewing Angle
• Common-Cathode Configuration for Multiplex Applications
• 0.155”/3.9 mm Character Spacing
• Integrated Red Plastic Lens
• Optional Red Magnifying Lens

• Family Members and Applications

Type Products Digits Comments
R7H-122-9 Canon LE-81M, Heathkit IC-2009, Craig 4511, Kovac LE-808MR  
R7H-122-9M Interton PC 2008  No R7H-122 marking
R7H-122-9A Bowmar MX20, MX25  Magnifying Lens

 

• Genealogy

Type Products Relationship Comments
R7H-122-11 Canon LE-100 Relative 11 digits
DIS114   Relative Different PCB
DIS206A   Relative Different PCB and Character spacing

 

• Technical Specifications

Item Min Typ Max Unit Comments
Display
Width		   2.40
60.8		   inch
mm		   
Display
Height		   0.72
18.3		   inch
mm		   
Display
Depth		   0.15
3.8		   inch
mm		  Including Printed Circuit Board,
 without Pins
PCB
Thickness		   0.06
1.6		   inch
mm		  FR4 
Lens
Width		   1.70
43.2		   inch
mm		   
Lens
Height		   0.50
12.7		   inch
mm		   
Lens
Depth		   0.09
2.2		   inch
mm		  
Character
Height		   0.120
3.00		   inch
mm		  
Character
Width		   0.085
2.20		   inch
mm		  w/o Decimal Point
Character
Slant Angle		   10   degrees   
Character
Spacing		   0.155
3.94		   inch
mm		  

• Technology

The displays are formed by bonding seven individual GaAsP (Gallium Arsenide Phosphide) Segment LED chips and one GaAsP Decimal Point LED chip per character directly to a double-sided FR4 printed circuit board (PCB) and placing a one-piece red acrylic protecting lens on top of the assembly with four heat stakes.

The die size of the Segment LED chip is approximately 42 mils * 13 mils / 1.1 mm * 0.3 mm, the die size of the Decimal Point LED chip is approximately 21 mils * 21 mils / 0.5 mm * 0.5 mm.

• Packaging

The R7H-122-9 uses a 2.40" / 60.8 mm by 0.72” / 18.3 mm rectangular printed circuit board (PCB) with 19 solder tabs with a 0.1” / 2.54 mm pitch arranged on the bottom of the display module.

The 19 solder tabs are either from circular or tear-drop shape.

• Pin Configuration

Pin Pol. Function
1   n.c.
2   n.c.
3 C Digit 9 (Minus Sign)
4 A C Segments
5 C Digit 8 (MSD)
6 A Decimal Points
7 C Digit 7
8 A A Segments
9 C Digit 6
10 A E Segments
11 C Digit 5
12 A D Segments
13 C Digit 4
14 A G Segments
15 C Digit 3
16 A B Segments
17 C Digit 2
18 A F Segments
19 C Digit 1 (LSD)
The Anode of the Segments A-G and Right-Hand Decimals and the Cathode of the Digits 1-9 are connected to the display in the pictured way. 
horizontal rule

If you have additions to the above datasheet please email: joerg@datamath.org.

© Joerg Woerner, January 2, 2022. No reprints without written permission.