# US 9,040,851 B2 · Keycap assembly with an interactive spring mechanism

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- Number: US 9,040,851 B2
- Document ID: US9040851B2
- Status: Granted
- Kind: B2
- Application number: 13/802,955
- Filed: 2013-03-14
- Published: 2014-02-06
- Granted: 2015-05-26
- Earliest claimed: 2012-08-06
- Assignees: Synaptics Incorporated
- Applicants: Synaptics Incorporated
- Inventors: Douglas M. Krumpelman
- Web page: https://patentgrep.com/patent/US9040851B2

## CPC

- H01H 13/85: characterised by tactile feedback features
- H03K 17/962: {Capacitive touch switches}
- H03K 17/98: having a plurality of control members, e.g. keyboard
- H01H 2221/044: Elastic part on actuator or casing
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A touchsurface assembly comprises a base, a pressable touchsurface, and a deflectable spring. The pressable touchsurface is configured to move between an unpressed position and a pressed position relative to the base. The deflectable spring comprises a fixed portion and a contact portion. The contact portion is configured to contact a spring guiding profile. As the touchsurface moves from the unpressed position to the pressed position, the contact portion physically interacts with different sections of the spring guiding profile. This interaction causes different deflections of the deflectable spring and produces reaction forces that resist keycap motion toward the pressed position and bias the keycap toward the unpressed position.

## Claims

### Claim 1

A key assembly comprising:
a base;
a keycap configured to move between an unpressed position and a pressed position relative to the base, wherein the unpressed and pressed positions are separated in a press direction and in a first lateral direction orthogonal to the press direction; and
a deflectable spring comprising a fixed portion and a contact portion, the contact portion configured to contact a spring guiding profile, wherein the fixed portion and the spring guiding profile are fixed to different key assembly elements selected from group consisting of the base and the keycap,
wherein, as the keycap moves from the unpressed position to the pressed position, the contact portion physically interacts with different sections of the spring guiding profile, causing different deflections of the deflectable spring and producing reaction forces that resist keycap motion toward the pressed position and bias the keycap toward the unpressed position.

### Claim 2 (depends on 1)

The key assembly of claim 1, wherein the fixed portion is fixed to the base, and the spring guiding profile is fixed to the keycap.

### Claim 3 (depends on 1)

The key assembly of claim 1, wherein the fixed portion is fixed to the keycap, and the deflectable spring is fixed to the base.

### Claim 4 (depends on 1)

The key assembly of claim 1, wherein a same piece of material comprises the deflectable spring and the key assembly element to which the fixed portion of the deflectable spring is fixed.

### Claim 5 (depends on 1)

The key assembly of claim 1, wherein the deflectable spring and the key assembly element to which the fixed portion of the deflectable spring is fixed comprise different pieces of material, and wherein the deflectable spring comprises a metal.

### Claim 6 (depends on 1)

The key assembly of claim 1, wherein the reaction forces provide a tactile response comprising a first spatial rate of increasing resistance followed by a second spatial rate of increasing resistance, wherein the second spatial rate is lower than the first spatial rate.

### Claim 7 (depends on 1)

The key assembly of claim 1, wherein the spring guiding profile comprises a lateral extension extending in a second lateral direction orthogonal to the first lateral direction and the different deflections comprise components in a second lateral direction.

### Claim 8 (depends on 1)

The key assembly of claim 1, wherein the key guiding profile has a depth, and the key guiding profile varies in cross section along the depth.

### Claim 9 (depends on 1)

The key assembly of claim 1, wherein the spring guiding profile is located proximate to a first edge of the keycap, the key assembly further comprising:
a second deflectable spring comprising a second fixed portion and a second contact portion, the second contact portion configured to contact a second spring guiding profile located proximate to a second edge of the keycap opposite the first edge of the keycap, wherein the second deflectable spring is fixed to the key assembly element to which the first deflectable spring is affixed and the second spring guiding profile is fixed to the key assembly element to which the first spring guiding profile is affixed,
wherein, as the keycap moves from the unpressed position to the pressed position, the second contact portion interacts with different sections of the second spring guiding profile, causing second different deflections of the second deflectable spring and producing second reaction forces that resist keycap motion toward the pressed position and bias the keycap toward the unpressed position.

### Claim 10 (depends on 1)

The key assembly of claim 1, further comprising:
a capacitive sensor electrode configured to detect a pressed state of the keycap.

### Claim 11 (depends on 1)

The key assembly of claim 1, wherein initial reaction forces produced in response to an initial part of the keycap motion from the unpressed position to the pressed position provide an initial tactile response comprising an increasing resistance.

### Claim 12 (depends on 11)

The key assembly of claim 11, wherein subsequent reaction forces produced in response to a subsequent part of the keycap motion from the unpressed position to the pressed position provide a subsequent tactile response comprising a decreasing resistance.

### Claim 13 (depends on 1)

The key assembly of claim 1, wherein the deflectable spring comprises a locally deformable portion proximate to the contact portion, and wherein in response to an initial part of the keycap motion from the unpressed position to the pressed position, the locally deformable portion deforms and puts the deflectable spring in a release configuration.

### Claim 14 (depends on 13)

The key assembly of claim 13, wherein the locally deformable portion and the contact portion together comprise a hook-shaped section of the deflectable spring.

### Claim 15

A keyboard comprising:
a base;
a plurality of key assemblies, wherein each key assembly of the plurality of key assemblies comprises:
a keycap configured to move between an unpressed position and a pressed position relative to the base, wherein the unpressed and pressed positions are separated vertically and laterally;
a first deflectable spring comprising a first fixed portion and a first contact portion, the first contact portion configured to contact a first spring guiding profile located proximate to a first edge of the keycap, wherein the first fixed portion and the first spring guiding profile are fixed to different keyboard elements selected from group consisting of the base and the keycap; and
a second deflectable spring comprising a second fixed portion and a second contact portion, the second contact portion configured to contact a second spring guiding profile located proximate to a second edge of the keycap opposite the first edge of the keycap, wherein the second deflectable spring is fixed to the keyboard element to which the first deflectable spring is affixed and the second spring guiding profile is fixed to the keyboard element to which the first spring guiding profile is affixed,
wherein, as the keycap moves from the unpressed position to the pressed position, the first and second contact portions physically interact with first and second different sections of the first and second spring guiding profiles, causing first and second different deflections of the first and second deflectable springs and producing first and second reaction forces, respectively, wherein the first and second reaction forces resist keycap motion toward the pressed position and bias the keycap toward the unpressed position; and
a key sensor configured to detect pressed states of keycaps of the plurality of key assemblies.

### Claim 16 (depends on 15)

The keyboard of claim 15, wherein the first and second deflectable springs of a first key assembly of the plurality of key assemblies are fixed to the keycap of the first key assembly, and the first and second spring guiding profiles of the first key assembly are fixed to the base, and wherein the first and second deflectable springs of a second key assembly of the plurality of key assemblies are fixed to the keycap of the second key assembly, and the first and second spring guiding profiles of the second key assembly are fixed to the base.

### Claim 17 (depends on 15)

The keyboard of claim 15, wherein first and second initial reaction forces produced in response to an initial part of the keycap motion from the unpressed position to the pressed position provide an initial tactile response comprising an increasing resistance, and wherein first and second subsequent reaction forces produced in response to a subsequent part of the keycap motion from the unpressed position to the pressed position provide a subsequent tactile response comprising a decreasing resistance.

### Claim 18 (depends on 15)

The key assembly of claim 15, wherein the first and second reaction forces provide a tactile response comprising a first spatial rate of increasing resistance followed by a second spatial rate of increasing resistance, wherein the second spatial rate is lower than the first spatial rate.

### Claim 19 (depends on 15)

The keyboard of claim 15, wherein for a first key assembly of the plurality of key assemblies, the first and second spring guiding profiles comprise first and second extensions, respectively.

### Claim 20 (depends on 15)

The keyboard of claim 15, wherein for a first key assembly of the plurality of key assemblies, the first and second key guiding profiles each has a corresponding depth, and the first and second key guiding profile each varies in cross section along the corresponding depth.

### Claim 21 (depends on 15)

The keyboard of claim 15, wherein for a first key assembly of the plurality of key assemblies, the first and second deflectable springs comprise first and second locally deformable sections proximate to the first and second contact sections, respectively, and wherein in response to an initial part of the keycap motion from the unpressed position to the pressed position, the first and second locally deformable sections deform and put the first and second deflectable springs in first and second release configurations, respectively.

### Claim 22 (depends on 21)

The keyboard of claim 21, wherein for the first key assembly, the first locally deformable section and the first contact section comprise a first hook-shaped section of the first deflectable spring, and the second locally deformable section and the second contact section comprise a second hook-shaped section of the second deflectable spring.

### Claim 23

A method of affecting motion of a pressable touchsurface of a touchsurface assembly, wherein the pressable touchsurface is configured to move between an unpressed position and a pressed position relative to a base of the touchsurface assembly, wherein the unpressed and pressed positions are separated in a press direction and in a lateral direction orthogonal to the press direction, the method comprising:
in response to a press input to the pressable touchsurface, providing first reaction forces that resist pressable touchsurface motion from the unpressed position to the pressed position through physical interactions between different sections of a spring guiding profile and a contact portion that cause different deflections of a deflectable spring, the deflectable spring comprising a fixed portion, wherein the fixed portion and the spring guiding profile are fixed to different touchsurface assembly elements selected from group consisting of the base and the pressable touchsurface; and
in response to a removal of the press input, providing second reaction forces that bias the pressable touchsurface toward the unpressed position through second physical interactions between the spring guiding profile and the contact portion.

### Claim 24 (depends on 23)

The method of claim 23, wherein the providing the first reaction forces comprises:
providing forces for a snapover response as the pressable touchsurface moves from the unpressed position to the pressed position.

### Claim 25 (depends on 23)

The method of claim 23, wherein the providing the first reaction forces comprises:
providing forces through a deformation of a locally deformable section of the deflectable spring that puts the deflectable spring in a release configuration.